ERIC Educational Resources Information Center
Cerny, Joseph; Poskanzer, Arthur M.
1978-01-01
Among the light elements, nuclei with unequal numbers of protons and neutrons are highly unstable. Some survive just long enough to be detected and exhibit unusual regimes of radioactive decay. ( Autor/MA)
ERIC Educational Resources Information Center
Cerny, Joseph; Poskanzer, Arthur M.
1978-01-01
Among the light elements, nuclei with unequal numbers of protons and neutrons are highly unstable. Some survive just long enough to be detected and exhibit unusual regimes of radioactive decay. ( Autor/MA)
Quaglioni, S; Navratil, P; Roth, R
2009-12-15
The exact treatment of nuclei starting from the constituent nucleons and the fundamental interactions among them has been a long-standing goal in nuclear physics. Above all nuclear scattering and reactions, which require the solution of the many-body quantum-mechanical problem in the continuum, represent an extraordinary theoretical as well as computational challenge for ab initio approaches.We present a new ab initio many-body approach which derives from the combination of the ab initio no-core shell model with the resonating-group method [4]. By complementing a microscopic cluster technique with the use of realistic interactions, and a microscopic and consistent description of the nucleon clusters, this approach is capable of describing simultaneously both bound and scattering states in light nuclei. We will discuss applications to neutron and proton scattering on sand light p-shell nuclei using realistic nucleon-nucleon potentials, and outline the progress toward the treatment of more complex reactions.
A Multi-layered target for the Study of Neutron-Unbound Nuclei
NASA Astrophysics Data System (ADS)
Gueye, Paul; Frank, Nathan; Thoennessen, Michael
2013-04-01
The MoNA/LISA setup at the National Superconducting Cyclotron Laboratory at Michigan State University has provided an avenue to study the nuclear structure of unbound states/nuclei at and beyond the neutron drip line for the past decade using secondary beams from the Coupled Cyclotron Facility. A new multi-layered Si/Be active target is planned to be built to specifically study neutron unbound nuclei. In these experiments the decay energy is reconstructed from fragment-neutron coincidence measurements which are typically low in count rate. The multi-layered target will allow the use of thicker targets to increase the reaction rates, thus enabling to study currently out of reach nuclei such as 21C, 23C, and 24N. A description of the new setup and physics impact will be discussed.
A new plunger device to measure lifetimes of unbound states in tagged exotic nuclei
NASA Astrophysics Data System (ADS)
Taylor, M. J.; Cullen, D. M.; Procter, M. G.; Smith, A. J.; Twist, V.; Jones, P. M.; Nieminen, P.; Grahn, T.; Butler, P. A.; Scheck, M.
2012-09-01
A new plunger device has been designed and is being built at the University of Manchester to measure lifetimes of unbound states in exotic nuclei approaching the proton drip-line. The device is designed to work in both vacuum and gas environments and will be used in conjunction with the gas filled separator RITU and the vacuum-mode separator MARA at the University of Jyväskylä, Finland. This will enable the accurate measurement of excited state lifetimes identified via isomer and charged-particle tagging. The plunger will be used to address many key facets of nuclear structure physics with particular emphasis on the effect of deformation on proton emission rates.
Decay dynamics of the unbound 25O and 26O nuclei
NASA Astrophysics Data System (ADS)
Hagino, K.; Sagawa, H.
2016-03-01
We study the ground and excited resonance states of 26O with a three-body model of 24O+n +n taking into account the coupling to the continuum. To this end, we use the new experimental data for the invariant mass spectroscopy of the unbound 25O and 26O nuclei, and present an update of three-body model calculations for the two-neutron decay of the 26O nucleus. With the new model inputs determined with the ground-state decay of 26O, we discuss the dineutron correlations and a halo nature of this nucleus, as well as the structure of the excited states. For the energy of the 2+ state, we achieve an excellent agreement with the experimental data with this calculation. We show that the 2+ state consists predominantly of the (d3/2) 2 configuration, for which the pairing interaction between the valence neutrons slightly decreases its energy from the unperturbed one. We also discuss the structure of excited 0+ states of the 26O nucleus. In particular, we show the existence of an excited 0+ state at 3.38 MeV, which is mainly composed of the (f7/2) 2 configuration.
Properties of nuclei probed by laser light
NASA Astrophysics Data System (ADS)
Neugart, Rainer
2017-03-01
Viewing objects as small as atomic nuclei by visible light sounds quite unrealistic. However, nuclei usually appear as constituents of atoms whose excitations are indeed associated with the absorption and emission of light. Nuclei can thus interact with light via the atomic system as a whole.
Geant4 Simulation of A Multi-layered target for the Study of Neutron-Unbound Nuclei
NASA Astrophysics Data System (ADS)
Gueye, Paul; Freeman, Jessica; Frank, Nathan; Thoennessen, Michael; MONA Collaboration
2013-10-01
The MoNA/LISA setup at the National Superconducting Cyclotron Laboratory at Michigan State University has provided an avenue to study the nuclear structure of unbound states/nuclei at and beyond the neutron dripline for the past decade using secondary beams from the Coupled Cyclotron Facility. A new multi-layered Si/Be active target is being designed to specifically study neutron-unbound nuclei. In these experiments the decay energy is reconstructed from fragment-neutron coincidence measurements that are typically low in count rate. The multi-layered target will allow the use of thicker targets to increase the reaction rates, thus enabling to study currently out of reach nuclei such as 21C, 23C and 24N. The Geant4 Monte Carlo toolkit is currently used to model these physics processes within the multi-layered target and expected invariant mass distributions. A description of the experimental setup and simulation work will be discussed. This work is supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0000979.
Electromagnetic structure of light nuclei
Pastore, Saori
Here, the present understanding of nuclear electromagnetic properties including electromagnetic moments, form factors and transitions in nuclei with A ≤ 10 is reviewed. Emphasis is on calculations based on nuclear Hamiltonians that include two- and three-nucleon realistic potentials, along with one- and two-body electromagnetic currents derived from a chiral effective field theory with pions and nucleons.
Electromagnetic structure of light nuclei
Pastore, Saori
2016-03-25
Here, the present understanding of nuclear electromagnetic properties including electromagnetic moments, form factors and transitions in nuclei with A ≤ 10 is reviewed. Emphasis is on calculations based on nuclear Hamiltonians that include two- and three-nucleon realistic potentials, along with one- and two-body electromagnetic currents derived from a chiral effective field theory with pions and nucleons.
Unified studies of structure and reactions in light unstable nuclei
NASA Astrophysics Data System (ADS)
Ito, Makoto
2016-06-01
The generalized two-center cluster model (GTCM), which can treat covalent, ionic and atomic configurations in general systems with two inert cores plus valence nucleons, is formulated in the basis of the microscopic cluster model. In this model, the covalent configurations constructed by the molecular orbital (MO) method and the atomic (or ionic) configuration obtained by the valence bonding (VB) method can be described in a consistent manner. GTCM is applied to the light neutron-rich system, 10,12Be = α + α + XN (X = 2,4), and the unified studies of the structural changes and the reaction problem are performed. In the structure study, the calculated energy levels are characterized in terms of the chemical bonding like structures, such as the covalent MO or ionic VB structures. The chemical bonding structures changes from level to level within a small energy interval. In the unbound region, the structure problem with the total system of α + α + XN and the reaction problem, induced by the collision of an asymptotic VB state of α+6,8He, are combined by GTCM. The properties of unbound resonant states are discussed in a close connection to the reaction mechanism, and some enhancement factors originated from the properties of the intrinsic states are predicted in the reaction observables. The unified calculation of the structures and the reactions is applied to the Coulomb shift problem in the mirror system, such the 10Be and 10C nuclei. The Coulomb displacement energy of the mirror systems are discussed.
Geometric symmetries in light nuclei
NASA Astrophysics Data System (ADS)
Bijker, R.
2017-06-01
The algebraic cluster model is is applied to study cluster states in the nuclei12C and16O. The observed level sequences can be understood in terms of the underlying discrete symmetry that characterizes the geometrical configuration of the α-particles, i.e. an equilateral triangle for12C, and a regular tetrahedron for16O. The structure of rotational bands provides a fingerprint of the underlying geometrical configuration of α-particles.
The first unbound states of mirror 9Be and 9B nuclei
NASA Astrophysics Data System (ADS)
Odsuren, Myagmarjav; Kikuchi, Yuma; Myo, Takayuki; Aikawa, Masayuki; Katō, Kiyoshi
2017-09-01
The structures of the first excited states of mirror 9Be and 9B nuclei are studied by using the α + α + N three-body model and the complex scaling method. The resonance energy with a decay width of the 1/2+ state of 9B is calculated by taking into account the consistency with photodisintegration cross sections of 9Be into the 1/2+ state. We also compare the results with the measured data and other theories.
Effective Interactions for Light Nuclei
NASA Astrophysics Data System (ADS)
Caldwell, Bryan R.
The G-matrix technique in which one is able to easily calculate ground and excited states of many-body systems is used to calculate the ground state energies and some excited levels of ^3H and ^4He. Energy independent effective interactions are obtained for these nuclei using the technique of Suzuki and Lee which requires the G-matrix and its derivatives with respect to starting energy. It is found that accurate energy derivatives of the G-matrix are necessary to obtain energy independence and thus analytic expressions are presented for these derivatives in both center-of-mass/relative and shell model coordinate systems. Several rules of thumb are given pertaining to the convergence criteria in both coordinate systems. Further, since the G-matrix includes only intra -channel two-body correlations outside the active space, we explore the effect on the binding energies when the active space is enlarged to include several major shells. By enlarging the active space, we hope to include the most important many-body correlations explicitly. It is found that when the active space includes more than 2 major shells, the effective interaction is well approximated by the G-matrix. Our results essentially agree with exact Faddeev calculations for ^3 H but underbind by about.5 MeV in ^4 He as compared to exact Yabukovsky and Green function Monte Carlo calculations. A possible reason for this underbinding, the inclusion of unlinked diagrams in the energy expansion, is studied. The energy independent G-matrix technique is then applied to the p-shell (^5He, ^6Li and ^7Li) where the active space includes all excitations up to 2 hbaromega. Zero, one, two and three -body effective interactions are extracted and it is found that a schematic two-parameter three-body potential can be used to approximate the effective three-body potential that results from the truncation of the active space.
Light nuclei from chiral EFT interactions
NASA Astrophysics Data System (ADS)
Navrátil, P.; Gueorguiev, V. G.; Vary, J. P.; Ormand, W. E.; Nogga, A.; Quaglioni, S.
2008-12-01
Recent developments in nuclear theory allow us to make a connection between quantum chromodynamics (QCD) and low-energy nuclear physics. First, chiral effective field theory (χEFT) provides a natural hierarchy to define two-nucleon ( NN), three-nucleon ( NNN), and even four-nucleon interactions. Second, ab-initio methods have been developed capable to test these interactions for light nuclei. In this contribution, we discuss ab-initio no-core shell-model (NCSM) calculations for s-shell and p-shell nuclei with NN and NNN interactions derived within χEFT.
Precision lifetime measurements in light exotic nuclei
NASA Astrophysics Data System (ADS)
McCutchan, Elizabeth
2017-01-01
A new generation of ab-initio calculations, based on realistic two- and three-body forces have had a profound impact on our understanding of nuclei. They have shed light on topics such as the origin of effective forces (like spin-orbit and tensor interactions) and the mechanisms behind cluster and pairing correlations. New precise data are required to both better parameterize the three body forces and to improve numerical methods. A sensitive probe of the structure of light nuclei comes from their electromagnetic transition rates. A refined Doppler Shift Attenuation Method (DSAM) will be outlined which is used to precisely measure lifetimes in light nuclei and helps to reduce and quantity systematic uncertainties in the measurement. Using this careful DSAM, we have made a series of precise measurements of electromagnetic transition strengths in Li isotopes, A =10 nuclei, and the exotic halo nucleus, 12Be. Various phenomena, such as alpha clustering and meson-exchange currents, can be investigated in these seemingly simple systems, while the collection of data spanning stable to neutron-rich, allows us to probe the influence of additional valence neutrons. This talk will report on what has been learned, and the challenges that lie in the future, both in experiment and theory, as we push to describing and measuring even more exotic systems. Work supported by the Office of Nuclear Physics, Office of Science of the U.S. Department of Energy under contract No. DE-AC02-98CH10886.
Associated strangeness production on light nuclei
NASA Astrophysics Data System (ADS)
Ernst, J.; Kingler, J.; Lippert, C.
1991-04-01
The study of light hyper-nuclei via associated strangeness production in (p, K+) reactions is discussed. Though the process is characterized by a very large momentum transfer the presence of short range correlations is expected to rise the cross section up to the order of nb/sr. Two approved proposals for high resolution studies of this reaction are discussed and respective detection limits are presented. The first is scheduled for October 1990 at the SPES4 spectrometer at the SATURNE acclerator (LNS Saclay). The second deals with the planned upgrading of the BIG KARL magnetic spectrograph at the cooled beam facility COSY being bulit at Forschungsanlage Jülich.
Probing Chiral Interactions in Light Nuclei
Nogga, A; Barrett, B R; Meissner, U; Witala, H; Epelbaum, E; Kamada, H; Navratil, P; Glockle, W; Vary, J P
2004-01-08
Chiral two- and three-nucleon interactions are studied in a few-nucleon systems. We investigate the cut-off dependence and convergence with respect to the chiral expansion. It is pointed out that the spectra of light nuclei are sensitive to the three-nucleon force structure. As an example, we present calculations of the 1{sup +} and 3{sup +} states of {sup 6}Li using the no-core shell model approach. The results show contributions of the next-to-next-to-leading order terms to the spectra, which are not correlated to the three-nucleon binding energy prediction.
Collectivity in Light Nuclei and the GDR
NASA Astrophysics Data System (ADS)
Maj, A.; Styczeń, J.; Kmiecik, M.; Bednarczyk, P.; Brekiesz, M.; GrȨBOSZ, J.; Lach, M.; MȨCZYŃSKI, W.; ZiȨBLIŃSKI, M.; Zuber, K.; Bracco, A.; Camera, F.; Benzoni, G.; Leoni, S.; Million, B.; Wieland, O.
2005-03-01
The results are presented from the experiments using the EUROBALL and RFD/HECTOR arrays, concerning various aspects of collectivity in light nuclei. A superdeformed band in 42Ca was found. A comparison of the GDR line shape data with the predictions of the thermal shape fluctuation model, based on the most recent rotating liquid drop LSD calculations, shows evidence for a Jacobi shape transition in hot, rapidly rotating 46Ti and strong Coriolis effects in the GDR strength function. The preferential feeding of the SD band in 42Ca by the GDR low energy component was observed
Statistical (?) decay of light hot nuclei
NASA Astrophysics Data System (ADS)
Baiocco, G.; Bruno, M.; D'Agostino, M.; Morelli, L.
2012-07-01
The reaction 12C+12C at 95 MeV beam energy has been measured using the GARFIELD+RCo apparatuses at Laboratori Nazionali di Legnaro LNL - INFN, Italy, in the framework of an experimental campaign proposed by the NUCL-EX collaboration. The aim is to progress in the understanding of statistical properties of light nuclei at excitation energies above particle emission thresholds, by measuring exclusive fusion-evaporation data. A theoretical study of the system, performed with a newly developed Monte Carlo Hauser-Feshbach code, is shown, together with preliminary results of the data analysis.
Cluster-shell competition in light nuclei
Itagaki, N.; Aoyama, S.; Okabe, S.; Ikeda, K.
2004-11-01
We demonstrate whether the cluster structure dissolves or remains when the shell-model-like model space is introduced in addition to the cluster model space in light nuclei. Although the binding energies of {sup 8}Be, {sup 10}Be, and {sup 10}B become larger by about 1-2 MeV by adding shell-model-like basis states to the {alpha}+{alpha}+N+N+{center_dot}{center_dot}{center_dot} basis states, the {alpha}-{alpha} structure is a dominant configuration of the ground states. However, {alpha}-breaking wave functions strongly mix in {sup 12}C, and the decrease of the energy from the 3{alpha} configuration by about 6 MeV is a clue to resolving a long-standing problem of the binding energies of {sup 12}C and {sup 16}O. The improved version of antisymmetrized molecular dynamics (AMD), AMD superposition of selected snapshots (AMD triple-S), is used to show the cluster-shell competition of these nuclei.
Anisotropic multicluster model in light nuclei
NASA Astrophysics Data System (ADS)
Gijón, A.; Gálvez, F. J.; Arias de Saavedra, F.; Buendía, E.
2016-06-01
Multicluster models consider that the nucleons can be moving around different centers in the nuclei. These models have been widely used to describe light nuclei but always considering that the mean field is composed of isotropic harmonic oscillators with different centers. In this work, we propose an extension of these models by using anisotropic harmonic oscillators. The strengths of these oscillators, the distance among the different centers and the disposition of the nucleons inside every cluster are free parameters which have been fixed using the variational criterion. All the one-body and two-body matrix elements have been analytically calculated. Only a numerical integration on the Euler angles is needed to carry out the projection on the values of the total spin of the state and its third component. We have studied the ground state and the first excited states of 8Be, 12C and 10Be getting good results for the energies. The disposition of the nucleons in the different clusters have also been analyzed by using projection on the different Cartesian planes getting much more information than when the radial one-body density is used.
Clusters and Halos in Light Nuclei
Neff, Thomas; Feldmeier, Hans
2009-08-26
The structure of light nuclei in the p- and sd-shell features exotic phenomena like halos and clustering. In the Fermionic Molecular Dynamics (FMD) approach we aim at a consistent microscopic description of well bound nuclei and of loosely bound exotic systems. This is possible due to the flexibility of the single-particle basis states using Gaussian wave-packets localized in phase space. Many-body basis states are Slater determinants projected on parity, angular and total linear momentum.The structure of {sup 12}C is discussed. Here the ground state band can be well described within a shell model picture but excited states above the three-{alpha} threshold, including the famous Hoyle state, show a pronounced cluster structure. As another example we study the structure of the Neon isotopes {sup 17-22}Ne. In {sup 17}Ne we find a large s{sup 2} occupation related to a large charge radius. The charge radius decreases for {sup 18}Ne but gets again very large for {sup 19}Ne and {sup 20}Ne which is explained by significant admixtures of {sup 3}He and {sup 4}He cluster components into to the ground state wave functions.
Clusters and Halos in Light Nuclei
NASA Astrophysics Data System (ADS)
Neff, Thomas; Feldmeier, Hans
2009-08-01
The structure of light nuclei in the p- and sd-shell features exotic phenomena like halos and clustering. In the Fermionic Molecular Dynamics (FMD) approach we aim at a consistent microscopic description of well bound nuclei and of loosely bound exotic systems. This is possible due to the flexibility of the single-particle basis states using Gaussian wave-packets localized in phase space. Many-body basis states are Slater determinants projected on parity, angular and total linear momentum. The structure of 12C is discussed. Here the ground state band can be well described within a shell model picture but excited states above the three-α threshold, including the famous Hoyle state, show a pronounced cluster structure. As another example we study the structure of the Neon isotopes 17-22Ne. In 17Ne we find a large s2 occupation related to a large charge radius. The charge radius decreases for 18Ne but gets again very large for 19Ne and 20Ne which is explained by significant admixtures of 3He and 4He cluster components into to the ground state wave functions.
Clusters in neutron-rich light nuclei
NASA Astrophysics Data System (ADS)
Jelavić Malenica, D.; Milin, M.; Di Pietro, A.; Figuera, P.; Lattuada, M.; Miljanić, D.; Musumarra, A.; Pellegriti, M. G.; Prepolec, L.; Scuderi, V.; Skukan, N.; Soić, N.; Torresi, D.; Uroić, M.
2016-05-01
Due to their high selectivity, transfer and sequential decay reactions are powerful tools for studies of both single particle (nucleon) and cluster states in light nuclei. Their use is particularly simple for investigations of α-particle clustering (because α-particle has Jπ=0+, which simplifies spin and parity assignments to observed cluster states), but they are also easily applicable to other types of clustering. Recent results on clustering in neutron-rich isotopes of beryllium, boron and carbon obtained measuring the 10B+10B reactions (at 50 and 72 MeV) are presented. The highly efficient and segmented detector systems used, built from 4 Double Sided Silicon Strip Detectors (DSSSD) allowed detection of double and multiple coincidences and, in that way, studies of states populated in transfer reactions, as well as their sequential decay.
Direct observation of light focusing by single photoreceptor cell nuclei.
Błaszczak, Zuzanna; Kreysing, Moritz; Guck, Jochen
2014-05-05
The vertebrate retina is inverted with respect to its optical function, which requires light to pass through the entire tissue prior to detection. The last significant barrier for photons to overcome is the outer nuclear layer formed by photoreceptor cell (PRC) nuclei. Here we experimentally characterise the optical properties of PRC nuclei using bright-field defocusing microscopy to capture near-field intensity distributions behind individual nuclei. We find that some nuclei efficiently focus incident light confirming earlier predictions based on comparative studies of chromatin organisation in nocturnal and diurnal mammals. The emergence of light focusing during the development of mouse nuclei highlights the acquired nature of the observed lens-like behaviour. Optical characterisation of these nuclei is an important first step towards an improved understanding of how light transmission through the retina is influenced by its constituents.
Quantum Monte Carlo calculations for light nuclei
Wiringa, R.B.
1997-10-01
Quantum Monte Carlo calculations of ground and low-lying excited states for nuclei with A {le} 8 have been made using a realistic Hamiltonian that fits NN scattering data. Results for more than two dozen different (J{sup {pi}}, T) p-shell states, not counting isobaric analogs, have been obtained. The known excitation spectra of all the nuclei are reproduced reasonably well. Density and momentum distributions and various electromagnetic moments and form factors have also been computed. These are the first microscopic calculations that directly produce nuclear shell structure from realistic NN interactions.
Exotic clusters in an unbound region of light neutron-rich systems
NASA Astrophysics Data System (ADS)
Ito, Makoto
2009-10-01
In light neutron-rich systems, many kinds of molecular structures are discussed from the view point of the clustering phenomena.In particular, much attention has been concentrated on Be isotopes. The molecular orbital (MO), such as &-circ; and &+circ; associated with the covalent binding of atomic molecules, have been shown to give a good description for the low-lying states of these isotopes. In their highly-excited states, furthermore, recent experiments revealed the existence of the interesting resonant states which dominantly decay to the ^6,8He fragments. In this report, we show the unified study of the exotic structures of ^12Be=α+α+4N in an unbound region and the α+^6,8He resonant scattering. We applied the generalized two-center cluster model in which the covalent MO and the atomic orbital (AO) configurations with ^xHe+^yHe could be described in a unified manner. First, we calculated the energy spectra below an α decay-threshold. The (π32^-)^2 (σ12^+)^2 configuration corresponding to ν(0p)^4(sd)^2 becomes the ground state, while (π3 2^-)^2(π12^-)^2 having a large overlap with ν(0p)^6 appears as the first excited state. The rotational band of the ground state reaches to the maximum spin of J^π = 8^+. This result means that the magicity of N=8 is broken in ^12Be due to the formation of (π3 2^-)^2(σ12^+)^2. Next, we solved the scattering problem of α+^8He and identified the several resonance poles. In the continuum region, we found the rotational bands having the AO configurations of α+^8He, ^6He+^6He, and ^5He+^7 He. Furthermore, a much more exotic band appears in the same energy region. In this band, two valence neutrons are localized at individual α-cores (the ^5He+^5He cluster), while the other two neutrons form the covalent &+circ;- bonding between two ^5He clusters; hence, it has a ``hybrid structure'' between the MO configuration and the AO one. In the J^π=0^+ state, it is strongly excited by the two-neutron transfer reaction, α+^8He
Form Factors and Radii of Light Nuclei
Sick, Ingo
2015-09-15
We discuss the determination of electromagnetic form factors from the world data on electron–nucleus scattering for nuclei Z ≤ 3, with particular emphasis on the derivation of the moments required for comparison with measurements from electronic/muonic atoms and isotope shifts.
AMS with light nuclei at small accelerators
NASA Astrophysics Data System (ADS)
Stan-Sion, C.; Enachescu, M.
2017-06-01
AMS applications with lighter nuclei are presented. It will be shown how Carbon-14, Boron-10, Beryllium-10, and Tritium-3 can be used to provide valuable information in forensic science, environmental physics, nuclear pollution, in material science and for diagnose of the plasma confinement in fusion reactors. Small accelerators are reliable, efficient and possess the highest ion beam transmissions that confer high precision in measurements.
Green's function calculations of light nuclei
NASA Astrophysics Data System (ADS)
Sun, ZhongHao; Wu, Qiang; Xu, FuRong
2016-09-01
The influence of short-range correlations in nuclei was investigated with realistic nuclear force. The nucleon-nucleon interaction was renormalized with V lowk technique and applied to the Green's function calculations. The Dyson equation was reformulated with algebraic diagrammatic constructions. We also analyzed the binding energy of 4He, calculated with chiral potential and CD-Bonn potential. The properties of Green's function with realistic nuclear forces are also discussed.
New measurements of the EMC effect in light nuclei
A. Daniel
2009-12-01
Modifications of structure functions in nuclei (EMC effect) suggest that the nuclear quark distribution function is not just the incoherent sum of the proton and neutron distributions, and made clear the importance of nuclear effects even in high energy measurements. Jefferson Lab experiment E03-103 made precise measurements of the EMC effect in few-body and heavy nuclei with emphasis on the large x region. Data from the light nuclei suggests that the nuclear dependence of the high x quark distribution may depend on the nucleon's local environment, rather than being a purely bulk effect.
Quantum Monte Carlo calculations for light nuclei.
Wiringa, R. B.
1998-10-23
Quantum Monte Carlo calculations of ground and low-lying excited states for nuclei with A {le} 8 are made using a realistic Hamiltonian that fits NN scattering data. Results for more than 40 different (J{pi}, T) states, plus isobaric analogs, are obtained and the known excitation spectra are reproduced reasonably well. Various density and momentum distributions and electromagnetic form factors and moments have also been computed. These are the first microscopic calculations that directly produce nuclear shell structure from realistic NN interactions.
Quantum Monte Carlo calculations for light nuclei
Wiringa, R.B.
1998-08-01
Quantum Monte Carlo calculations of ground and low-lying excited states for nuclei with A {le} 8 are made using a realistic Hamiltonian that fits NN scattering data. Results for more than 30 different (j{sup {prime}}, T) states, plus isobaric analogs, are obtained and the known excitation spectra are reproduced reasonably well. Various density and momentum distributions and electromagnetic form factors and moments have also been computed. These are the first microscopic calculations that directly produce nuclear shell structure from realistic NN interactions.
Transverse momentum dependent quark and gluon distributions of light nuclei
NASA Astrophysics Data System (ADS)
Nematollahi, H.; Yazdanpanah, M. M.
2017-07-01
We investigate the unpolarized transverse momentum dependent (TMD) structure of light nuclei in the modified chiral quark exchange model (QEM), for the first time. To this end, we calculate the TMD quark and gluon distributions inside the bound state nucleons of the light nuclei based on the modified chiral quark model (χ {{QM}}) in which the TMD bare quark distributions of the bounded nucleons are needed. In order to compute these bare distributions, we first obtain the bare quark momentum densities using the QEM and then calculate the TMD bare distributions applying a theoretical method in which the light-cone variables are used. Finally, considering the nucleon structure of helium, tritium and deuteron nuclei, we obtain their TMD quark and gluon densities at low Q 2 scale. It is shown that our results have appropriate properties that are expected for the TMD distribution functions.
Light element production by low energy nuclei from massive stars
NASA Technical Reports Server (NTRS)
Vangioni-Flam, E.; Casse, M.; Ramaty, R.
1997-01-01
The Orion complex is a source of gamma rays attributed to the de-excitation of fast carbon and oxygen nuclei excited through interactions with ambient hydrogen and helium. This has consequences for the production and evolution of light isotopes in the Galaxy, as massive stars appear as prolific sources of C-O rich low energy nuclei. The different stages of massive star evolution are considered in relation to the acceleration of nuclei to moderate energies. It is concluded that the low energy nuclear component originating from massive stars plays a larger role than the usual Galactic cosmic rays in shaping the evolution of Li-6, Be-9, B-10 and B-11, especially in the early Galactic evolution. The enhancement of the B-11/B-10 ratio observed in meteorites and in the interstellar medium is attributed to the interaction of low energy carbon nuclei with ambient H and to a lesser degree, to neutrino spallation.
Light element production by low energy nuclei from massive stars
NASA Technical Reports Server (NTRS)
Vangioni-Flam, E.; Casse, M.; Ramaty, R.
1997-01-01
The Orion complex is a source of gamma rays attributed to the de-excitation of fast carbon and oxygen nuclei excited through interactions with ambient hydrogen and helium. This has consequences for the production and evolution of light isotopes in the Galaxy, as massive stars appear as prolific sources of C-O rich low energy nuclei. The different stages of massive star evolution are considered in relation to the acceleration of nuclei to moderate energies. It is concluded that the low energy nuclear component originating from massive stars plays a larger role than the usual Galactic cosmic rays in shaping the evolution of Li-6, Be-9, B-10 and B-11, especially in the early Galactic evolution. The enhancement of the B-11/B-10 ratio observed in meteorites and in the interstellar medium is attributed to the interaction of low energy carbon nuclei with ambient H and to a lesser degree, to neutrino spallation.
Photodisintegration of Light Nuclei with CLAS
Ilieva, Yordanka Yordanova; Zachariou, Nicholas
2013-08-01
We report preliminary results of photodisintegration of deuteron and {sup 3}He measured with CLAS at Jefferson Lab. We have extracted the beam-spin asymmetry for the {vector {gamma}}d {yields} pn reaction at photon energies from 1.1 GeV to 2.3 GeV and proton center-of-mass (c.m.) angles between 35{degrees} and 135{degrees} . Our data show interesting evolution of the angular dependence of the observable as the photon energy increases. The energy dependence of the beam-spin asymmetry at 90 shows a change of slope at photon energy of 1.6 GeV. A comparison of our data with model calculations suggests that a fully non-perturbative treatment of the underlying dynamics may be able to describe the data better than a model based on hard scattering. We have observed onset of dimensional scaling in the cross section of two-body photodisintegration of {sup 3}He at remarkably low energy and momentum transfer, which suggests that partonic degrees of freedom may be relevant for the description of nuclei at energies lower than previously considered.
Dilute Excited States in Light Nuclei
NASA Astrophysics Data System (ADS)
Demyanova, A. S.; Ogloblin, A. A.; Danilov, A. N.; Goncharov, S. A.; Belyaeva, T. L.; Trzaska, W. H.
2015-11-01
A review of measurements of the radii of 11B, 12C and 13C nuclei in some excited states, whose structure recently attracted a lot of attention, is presented. The differential cross-sections of the inelastic α-scattering were measured. The radii values were extracted from the date using the Modified Diffraction Model (MDM). The evidence that the famous Hoyle state (0+, 7.65 MeV) in 12C has the enhanced dimensions and is the head of a new rotational band (besides the known band based on the 12C ground state) was obtained. The radius of the second 2+ member state (E* = 9.8 or 9.6 MeV) was seen to be similar to that of the Hoyle state (~3.0 fm). A 4+ state was identified at E* = 13.75 MeV. The radii of the 8.86 MeV, 1/2- state in 13C and 8.56 MeV, 3/2- state in 11B are found to be close to that of the Hoyle state and these states can be considered as analogues of the latter. Comparison of the data with the predictions of some theoretical models, e.g., alpha condensation, has been made. The obtained results show that one may speak only about rudimentary manifestation of the condensate effects.
From light nuclei to nuclear matter the role of relativity?
Coester, F.; Physics
2003-11-10
The success of non-relativistic quantum dynamics in accounting for the binding energies and spectra of light nuclei with masses up to A=10 raises the question whether the same dynamics applied to infinite nuclear matter agrees with the empirical saturation properties of large nuclei. The simple unambiguous relation between few-nucleon and many-nucleon Hamiltonians is directly related to the Galilean covariance of nonrelativistic dynamics. Relations between the irreducible unitary representations of the Galilei and Poincare groups indicate that the 'nonrelativistic' nuclear Hamiltonians may provide sufficiently accurate approximations to Poincare invariant mass operators. In relativistic nuclear dynamics based on suitable Lagrangeans the intrinsic nucleon parity is an explicit, dynamically relevant, degree of freedom and the emphasis is on properties of nuclear matter. The success of this approach suggests the question how it might account for the spectral properties of light nuclei.
Thermal-neutron capture in light nuclei
Raman, S.; Jurney, E.T.; Lynn, J.E.
1996-10-01
We have made considerable progress toward the goal of carrying out thermal-neutron capture {gamma}-ray measurements on all stable isotopes below A=60. Information processed till now has significantly augmented the existing knowledge on the detailed nuclear level structure of many light nuclides. Most of this knowledge comes from our {gamma}-ray energies, level placements, and branching ratios of secondary transitions between low-lying states. Spectroscopic information is also contained in the cross sections of the primary transitions originating from the capturing state. This is deduced from the success of ``direct`` theories of neutron capture for many nuclides, especially those of light and near closed-shell character. 23 refs, 1 tab, 3 figs.
Electric dipole moments of light nuclei from {chi}EFT
Higa, Renato
2013-03-25
I present recent calculations of EDMs of light nuclei using chiral effective field theory techniques. At leading-order, we argue that they can be expressed in terms of six CP-violating low-energy constants. With our expressions, eventual non-zero measurements of EDMs of deuteron, helion, and triton can be combined to disentangle the different sources of CP-violation.
Enumeration of islets by nuclei counting and light microscopic analysis
Pisania, Anna; Papas, Klearchos K.; Powers, Daryl E.; Rappel, Michael J.; Omer, Abdulkadir; Bonner-Weir, Susan; Weir, Gordon C.; Colton, Clark K.
2010-01-01
Islet enumeration in impure preparations by conventional dithizone staining and visual counting is inaccurate and operator dependent. We examined nuclei counting for measuring the total number of cells in islet preparations, and we combined it with morphological analysis by light microscopy (LM) for estimating the volume fraction of islets in impure preparations. Cells and islets were disrupted with lysis solution and shear, and accuracy of counting successively diluted nuclei suspensions was verified with: (1) visual counting in a hemacytometer after staining with crystal violet, and automatic counting by (2) aperture electrical resistance measurement and (3) flow cytometer measurement after staining with 7-aminoactinomycin-D. DNA content averaged 6.5 and 6.9 pg DNA/cell for rat and human islets, respectively, in agreement with literature estimates. With pure rat islet preparations, precision improved with increasing counts, and samples with about 160 or more islets provided a coefficient of variation of about 6%. Aliquots of human islet preparations were processed for LM analysis by stereological point counting. Total nuclei counts and islet volume fraction from LM analysis were combined to obtain the number of islet equivalents (IE). Total number of IE by the standard method of dithizone staining/manual counting was overestimated by about 90% compared to LM/nuclei counting for 12 freshly isolated human islet research preparations. Nuclei counting combined with islet volume fraction measurements from light microscopy is a novel method for achieving accurate islet enumeration. PMID:20697375
Electric dipole moments of light nuclei
NASA Astrophysics Data System (ADS)
Mereghetti, Emanuele
2017-01-01
Electric dipole moments (EDMs) are extremely sensitive probes of physics beyond the Standard Model (SM). A vibrant experimental program is in place, with the goal to improve the existing neutron EDM bound by one/two orders of magnitude, and to test new ideas for the measurement of EDMs of light ions, such as deuteron and helium, at a comparable level. The success of this program, and its implications for physics beyond the SM, relies on the precise calculation of the EDMs in terms of the couplings of CP-violating operators. In light of the non-perturbative nature both of QCD at low energy and of the nuclear interactions, these calculations have proven difficult, and are affected by large theoretical uncertainties. In this talk I will review the progress that in recent years has been achieved on different aspects of the calculation of hadronic and nuclear EDMs. In particular, I will discuss how the interplay between lattice QCD and Chiral Effective Field Theory (EFT) has allowed to reduce a set of hadronic uncertainties. Finally, I will discuss how the measurements of th EDMs of one, two and three nucleon systems can be used to discriminate between various possible mechanisms of time-reversal violation at high energy.
Vaporization of comet nuclei - Light curves and life times
NASA Technical Reports Server (NTRS)
Cowan, J. J.; Ahearn, M. F.
1979-01-01
The effects of vaporization from the nucleus of a comet are examined and it is shown that a latitude dependence of vaporization can explain the asymmetries in cometary light curves. An attempt is made to explain the observed variation in molecular production rates with heliocentric distance when employing CO2 and clathrate hydrate ice as cometary nuclei substances. The energy balance equation and the vapor pressure equations of water and CO2 are used in calculating the vaporization from a surface. Calculations were carried out from both dry-ice and water-ice nuclei, using a variety of different effective visual albedos, but primarily for a thermal infrared of 0 (emission). Attention is given to cometary lifetimes and light curves and it was determined that the asymmetry in light curves occurs (occasionally) as a 'seasonal' effect due to a variation in the angle between the comet's rotation axis and the sun-comet line.
Proton-decaying, light nuclei accessed via the invariant-mass method
NASA Astrophysics Data System (ADS)
Brown, Kyle
2017-01-01
Two-nucleon decay is the most recently discovered nuclear decay mode. For proton-rich nuclei, the majority of multi-proton decays occur via sequential steps of one-proton emission. Direct two-proton (2p) decay was believed to occur only in even-Z nuclei beyond the proton drip line where one-proton decay is energy forbidden. This has been observed for the ground states of around a dozen nuclei including 6Be, the lightest case, and 54Zn, the heaviest case. Direct 2p decay has also recently been observed for isobaric analog states where all possible 1p intermediates are either isospin allowed and energy forbidden, or energy-allowed and isospin forbidden. For light proton emitters, the lifetimes are short enough that the invariant-mass technique is ideal for measuring the decay energy, intrinsic width and, for multi-proton decays, the momentum correlations between the fragments. I will describe recent measurements of proton emitters using the invariant-mass technique with the High Resolution Array (HiRA). I will present a new, high-statistics measurement on the sequential 2p decay of excited states in 17Ne. Measuring the momentum correlations between the decay fragments allow us to determine the 1p intermediate state through which the decay proceeds. I will present data on the isobaric-analog pair 8C and 8BIAS, which highlight the two known types of direct 2p decay. I will also present the first observation of 17Na, which is unbound with respect to three-proton emission. Finally I will present a new measurement on the width of the first-excited state of 9C and compare to recent theoretical calculations.
Comparison of Muon Capture in Light and in Heavy Nuclei
Measday, David F.; Stocki, Trevor J.
2007-10-26
We have recently completed an experimental study at TRIUMF of muon capture in the following elements, N, Al, Si, Ca, Fe, Ni, I, Au, and Bi. We detected the nuclear gamma rays emitted by the product nuclei after muon capture. The energy of the gamma ray identifies the source nuclide, and thus the reaction which has occurred. Our data are of better quality, and more comprehensive than any other data set in the literature. The ({mu}{sup -},{nu}n) reaction is always dominant. In light nuclei, reactions such as ({mu}{sup -},{nu}p) and ({mu}{sup -},{nu}pn) can occur, but not for heavy nuclei. However the reverse is true for reactions such as ({mu}{sup -},{nu}3n) and ({mu}{sup -},{nu}4n), which are very rare in light nuclei, but easily detected in heavy elements. We shall discuss how such information can be useful in calculations of neutrino-nucleus interactions, and of electron-capture in supernovae.
Precision measurement of the mass difference between light nuclei and anti-nuclei
Adam, J.
2015-08-17
The measurement of the mass differences for systems bound by the strong force has reached a very high precision with protons and anti-protons. The extension of such measurement from (anti-)baryons to (anti-)nuclei allows one to probe any difference in the interactions between nucleons and anti-nucleons encoded in the (anti-)nuclei masses. Also, this force is a remnant of the underlying strong interaction among quarks and gluons and can be described by effective theories, but cannot yet be directly derived from quantum chromodynamics. Here we report a measurement of the difference between the ratios of the mass and charge of deuterons (d) and anti-deuterons (more » $$-\\atop{d}$$), and 3He and 3$$-\\atop{He}$$nuclei carried out with the ALICE (A Large Ion Collider Experiment) detector in Pb–Pb collisions at a centre-of-mass energy per nucleon pair of 2.76 TeV. Our direct measurement of the mass-over-charge differences confirms CPT invariance to an unprecedented precision in the sector of light nuclei. This fundamental symmetry of nature, which exchanges particles with anti-particles, implies that all physics laws are the same under the simultaneous reversal of charge(s) (charge conjugation C), reflection of spatial coordinates (parity transformation P) and time inversion (T).« less
Precision measurement of the mass difference between light nuclei and anti-nuclei
NASA Astrophysics Data System (ADS)
Alice Collaboration; Adam, J.; Adamová, D.; Aggarwal, M. M.; Aglieri Rinella, G.; Agnello, M.; Agrawal, N.; Ahammed, Z.; Ahmed, I.; Ahn, S. U.; Aimo, I.; Aiola, S.; Ajaz, M.; Akindinov, A.; Alam, S. N.; Aleksandrov, D.; Alessandro, B.; Alexandre, D.; Alfaro Molina, R.; Alici, A.; Alkin, A.; Alme, J.; Alt, T.; Altinpinar, S.; Altsybeev, I.; Alves Garcia Prado, C.; Andrei, C.; Andronic, A.; Anguelov, V.; Anielski, J.; Antičić, T.; Antinori, F.; Antonioli, P.; Aphecetche, L.; Appelshäuser, H.; Arcelli, S.; Armesto, N.; Arnaldi, R.; Aronsson, T.; Arsene, I. C.; Arslandok, M.; Augustinus, A.; Averbeck, R.; Azmi, M. D.; Bach, M.; Badalà, A.; Baek, Y. W.; Bagnasco, S.; Bailhache, R.; Bala, R.; Baldisseri, A.; Ball, M.; Baltasar Dos Santos Pedrosa, F.; Baral, R. C.; Barbano, A. M.; Barbera, R.; Barile, F.; Barnaföldi, G. G.; Barnby, L. S.; Barret, V.; Bartalini, P.; Bartke, J.; Bartsch, E.; Basile, M.; Bastid, N.; Basu, S.; Bathen, B.; Batigne, G.; Batista Camejo, A.; Batyunya, B.; Batzing, P. C.; Bearden, I. G.; Beck, H.; Bedda, C.; Behera, N. K.; Belikov, I.; Bellini, F.; Bello Martinez, H.; Bellwied, R.; Belmont, R.; Belmont-Moreno, E.; Belyaev, V.; Bencedi, G.; Beole, S.; Berceanu, I.; Bercuci, A.; Berdnikov, Y.; Berenyi, D.; Bertens, R. A.; Berzano, D.; Betev, L.; Bhasin, A.; Bhat, I. R.; Bhati, A. K.; Bhattacharjee, B.; Bhom, J.; Bianchi, L.; Bianchi, N.; Bianchin, C.; Bielčík, J.; Bielčíková, J.; Bilandzic, A.; Biswas, S.; Bjelogrlic, S.; Blanco, F.; Blau, D.; Blume, C.; Bock, F.; Bogdanov, A.; Bøggild, H.; Boldizsár, L.; Bombara, M.; Book, J.; Borel, H.; Borissov, A.; Borri, M.; Bossú, F.; Botje, M.; Botta, E.; Böttger, S.; Braun-Munzinger, P.; Bregant, M.; Breitner, T.; Broker, T. A.; Browning, T. A.; Broz, M.; Brucken, E. J.; Bruna, E.; Bruno, G. E.; Budnikov, D.; Buesching, H.; Bufalino, S.; Buncic, P.; Busch, O.; Buthelezi, Z.; Buxton, J. T.; Caffarri, D.; Cai, X.; Caines, H.; Calero Diaz, L.; Caliva, A.; Calvo Villar, E.; Camerini, P.; Carena, F.; Carena, W.; Castillo Castellanos, J.; Castro, A. J.; Casula, E. A. R.; Cavicchioli, C.; Ceballos Sanchez, C.; Cepila, J.; Cerello, P.; Chang, B.; Chapeland, S.; Chartier, M.; Charvet, J. L.; Chattopadhyay, Subhasis; Chattopadhyay, Sukalyan; Chelnokov, V.; Cherney, M.; Cheshkov, C.; Cheynis, B.; Chibante Barroso, V.; Chinellato, D. D.; Chochula, P.; Choi, K.; Chojnacki, M.; Choudhury, S.; Christakoglou, P.; Christensen, C. H.; Christiansen, P.; Chujo, T.; Chung, S. U.; Cicalo, C.; Cifarelli, L.; Cindolo, F.; Cleymans, J.; Colamaria, F.; Colella, D.; Collu, A.; Colocci, M.; Conesa Balbastre, G.; Conesa Del Valle, Z.; Connors, M. E.; Contreras, J. G.; Cormier, T. M.; Corrales Morales, Y.; Cortés Maldonado, I.; Cortese, P.; Cosentino, M. R.; Costa, F.; Crochet, P.; Cruz Albino, R.; Cuautle, E.; Cunqueiro, L.; Dahms, T.; Dainese, A.; Danu, A.; Das, D.; Das, I.; Das, S.; Dash, A.; Dash, S.; de, S.; de Caro, A.; de Cataldo, G.; de Cuveland, J.; de Falco, A.; de Gruttola, D.; De Marco, N.; de Pasquale, S.; Deisting, A.; Deloff, A.; Dénes, E.; D'Erasmo, G.; di Bari, D.; di Mauro, A.; di Nezza, P.; Diaz Corchero, M. A.; Dietel, T.; Dillenseger, P.; Divià, R.; Djuvsland, Ø.; Dobrin, A.; Dobrowolski, T.; Domenicis Gimenez, D.; Dönigus, B.; Dordic, O.; Dubey, A. K.; Dubla, A.; Ducroux, L.; Dupieux, P.; Ehlers, R. J.; Elia, D.; Engel, H.; Erazmus, B.; Erhardt, F.; Eschweiler, D.; Espagnon, B.; Estienne, M.; Esumi, S.; Evans, D.; Evdokimov, S.; Eyyubova, G.; Fabbietti, L.; Fabris, D.; Faivre, J.; Fantoni, A.; Fasel, M.; Feldkamp, L.; Felea, D.; Feliciello, A.; Feofilov, G.; Ferencei, J.; Fernández Téllez, A.; Ferreiro, E. G.; Ferretti, A.; Festanti, A.; Figiel, J.; Figueredo, M. A. S.; Filchagin, S.; Finogeev, D.; Fionda, F. M.; Fiore, E. M.; Fleck, M. G.; Floris, M.; Foertsch, S.; Foka, P.; Fokin, S.; Fragiacomo, E.; Francescon, A.; Frankenfeld, U.; Fuchs, U.; Furget, C.; Furs, A.; Fusco Girard, M.; Gaardhøje, J. J.; Gagliardi, M.; Gago, A. M.; Gallio, M.; Gangadharan, D. R.; Ganoti, P.; Gao, C.; Garabatos, C.; Garcia-Solis, E.; Gargiulo, C.; Gasik, P.; Germain, M.; Gheata, A.; Gheata, M.; Ghosh, P.; Ghosh, S. K.; Gianotti, P.; Giubellino, P.; Giubilato, P.; Gladysz-Dziadus, E.; Glässel, P.; Goméz Coral, D. M.; Gomez Ramirez, A.; González-Zamora, P.; Gorbunov, S.; Görlich, L.; Gotovac, S.; Grabski, V.; Graczykowski, L. K.; Grelli, A.; Grigoras, A.; Grigoras, C.; Grigoriev, V.; Grigoryan, A.; Grigoryan, S.; Grinyov, B.; Grion, N.; Grosse-Oetringhaus, J. F.; Grossiord, J.-Y.; Grosso, R.; Guber, F.; Guernane, R.; Guerzoni, B.; Gulbrandsen, K.; Gulkanyan, H.; Gunji, T.; Gupta, A.; Gupta, R.; Haake, R.; Haaland, Ø.; Hadjidakis, C.; Haiduc, M.; Hamagaki, H.; Hamar, G.; Hanratty, L. D.; Hansen, A.; Harris, J. W.; Hartmann, H.; Harton, A.; Hatzifotiadou, D.; Hayashi, S.; Heckel, S. T.; Heide, M.; Helstrup, H.; Herghelegiu, A.; Herrera Corral, G.; Hess, B. A.; Hetland, K. F.; Hilden, T. E.; Hillemanns, H.; Hippolyte, B.; Hristov, P.; Huang, M.; Humanic, T. J.; Hussain, N.; Hussain, T.; Hutter, D.; Hwang, D. S.; Ilkaev, R.; Ilkiv, I.; Inaba, M.; Ionita, C.; Ippolitov, M.; Irfan, M.; Ivanov, M.; Ivanov, V.; Izucheev, V.; Jacobs, P. M.; Jahnke, C.; Jang, H. J.; Janik, M. A.; Jayarathna, P. H. S. Y.; Jena, C.; Jena, S.; Jimenez Bustamante, R. T.; Jones, P. G.; Jung, H.; Jusko, A.; Kalinak, P.; Kalweit, A.; Kamin, J.; Kang, J. H.; Kaplin, V.; Kar, S.; Karasu Uysal, A.; Karavichev, O.; Karavicheva, T.; Karpechev, E.; Kebschull, U.; Keidel, R.; Keijdener, D. L. D.; Keil, M.; Khan, K. H.; Khan, M. Mohisin; Khan, P.; Khan, S. A.; Khanzadeev, A.; Kharlov, Y.; Kileng, B.; Kim, B.; Kim, D. W.; Kim, D. J.; Kim, H.; Kim, J. S.; Kim, Mimae.; Kim, Minwoo; Kim, S.; Kim, T.; Kirsch, S.; Kisel, I.; Kiselev, S.; Kisiel, A.; Kiss, G.; Klay, J. L.; Klein, C.; Klein, J.; Klein-Bösing, C.; Kluge, A.; Knichel, M. L.; Knospe, A. G.; Kobayashi, T.; Kobdaj, C.; Kofarago, M.; Köhler, M. K.; Kollegger, T.; Kolojvari, A.; Kondratiev, V.; Kondratyeva, N.; Kondratyuk, E.; Konevskikh, A.; Kour, M.; Kouzinopoulos, C.; Kovalenko, V.; Kowalski, M.; Kox, S.; Koyithatta Meethaleveedu, G.; Kral, J.; Králik, I.; Kravčáková, A.; Krelina, M.; Kretz, M.; Krivda, M.; Krizek, F.; Kryshen, E.; Krzewicki, M.; Kubera, A. M.; Kučera, V.; Kucheriaev, Y.; Kugathasan, T.; Kuhn, C.; Kuijer, P. G.; Kulakov, I.; Kumar, A.; Kumar, J.; Kumar, L.; Kurashvili, P.; Kurepin, A.; Kurepin, A. B.; Kuryakin, A.; Kushpil, S.; Kweon, M. J.; Kwon, Y.; La Pointe, S. L.; La Rocca, P.; Lagana Fernandes, C.; Lakomov, I.; Langoy, R.; Lara, C.; Lardeux, A.; Lattuca, A.; Laudi, E.; Lea, R.; Leardini, L.; Lee, G. R.; Lee, S.; Legrand, I.; Lehnert, J.; Lemmon, R. C.; Lenti, V.; Leogrande, E.; León Monzón, I.; Leoncino, M.; Lévai, P.; Li, S.; Li, X.; Lien, J.; Lietava, R.; Lindal, S.; Lindenstruth, V.; Lippmann, C.; Lisa, M. A.; Ljunggren, H. M.; Lodato, D. F.; Loenne, P. I.; Loggins, V. R.; Loginov, V.; Loizides, C.; Lopez, X.; López Torres, E.; Lowe, A.; Lu, X.-G.; Luettig, P.; Lunardon, M.; Luparello, G.; Maevskaya, A.; Mager, M.; Mahajan, S.; Mahmood, S. M.; Maire, A.; Majka, R. D.; Malaev, M.; Maldonado Cervantes, I.; Malinina, L.; Mal'Kevich, D.; Malzacher, P.; Mamonov, A.; Manceau, L.; Manko, V.; Manso, F.; Manzari, V.; Marchisone, M.; Mareš, J.; Margagliotti, G. V.; Margotti, A.; Margutti, J.; Marín, A.; Markert, C.; Marquard, M.; Martashvili, I.; Martin, N. A.; Martin Blanco, J.; Martinengo, P.; Martínez, M. I.; Martínez García, G.; Martinez Pedreira, M.; Martynov, Y.; Mas, A.; Masciocchi, S.; Masera, M.; Masoni, A.; Massacrier, L.; Mastroserio, A.; Matyja, A.; Mayer, C.; Mazer, J.; Mazzoni, M. A.; McDonald, D.; Meddi, F.; Menchaca-Rocha, A.; Meninno, E.; Mercado Pérez, J.; Meres, M.; Miake, Y.; Mieskolainen, M. M.; Mikhaylov, K.; Milano, L.; Milosevic, J.; Minervini, L. M.; Mischke, A.; Mishra, A. N.; Miśkowiec, D.; Mitra, J.; Mitu, C. M.; Mohammadi, N.; Mohanty, B.; Molnar, L.; Montaño Zetina, L.; Montes, E.; Morando, M.; Moreira de Godoy, D. A.; Moreno, L. A. P.; Moretto, S.; Morreale, A.; Morsch, A.; Muccifora, V.; Mudnic, E.; Mühlheim, D.; Muhuri, S.; Mukherjee, M.; Müller, H.; Mulligan, J. D.; Munhoz, M. G.; Murray, S.; Musa, L.; Musinsky, J.; Nandi, B. K.; Nania, R.; Nappi, E.; Naru, M. U.; Nattrass, C.; Nayak, K.; Nayak, T. K.; Nazarenko, S.; Nedosekin, A.; Nellen, L.; Ng, F.; Nicassio, M.; Niculescu, M.; Niedziela, J.; Nielsen, B. S.; Nikolaev, S.; Nikulin, S.; Nikulin, V.; Noferini, F.; Nomokonov, P.; Nooren, G.; Norman, J.; Nyanin, A.; Nystrand, J.; Oeschler, H.; Oh, S.; Oh, S. K.; Ohlson, A.; Okatan, A.; Okubo, T.; Olah, L.; Oleniacz, J.; Oliveira da Silva, A. C.; Oliver, M. H.; Onderwaater, J.; Oppedisano, C.; Ortiz Velasquez, A.; Oskarsson, A.; Otwinowski, J.; Oyama, K.; Ozdemir, M.; Pachmayer, Y.; Pagano, P.; Paić, G.; Pajares, C.; Pal, S. K.; Pan, J.; Pandey, A. K.; Pant, D.; Papikyan, V.; Pappalardo, G. S.; Pareek, P.; Park, W. J.; Parmar, S.; Passfeld, A.; Paticchio, V.; Paul, B.; Pawlak, T.; Peitzmann, T.; Pereira da Costa, H.; Pereira de Oliveira Filho, E.; Peresunko, D.; Pérez Lara, C. E.; Peskov, V.; Pestov, Y.; Petráček, V.; Petrov, V.; Petrovici, M.; Petta, C.; Piano, S.; Pikna, M.; Pillot, P.; Pinazza, O.; Pinsky, L.; Piyarathna, D. B.; Płoskoń, M.; Planinic, M.; Pluta, J.; Pochybova, S.; Podesta-Lerma, P. L. M.; Poghosyan, M. G.; Polichtchouk, B.; Poljak, N.; Poonsawat, W.; Pop, A.; Porteboeuf-Houssais, S.; Porter, J.; Pospisil, J.; Prasad, S. K.; Preghenella, R.; Prino, F.; Pruneau, C. A.; Pshenichnov, I.; Puccio, M.; Puddu, G.; Pujahari, P.; Punin, V.; Putschke, J.; Qvigstad, H.; Rachevski, A.; Raha, S.; Rajput, S.; Rak, J.; Rakotozafindrabe, A.; Ramello, L.; Raniwala, R.; Raniwala, S.; Räsänen, S. S.; Rascanu, B. T.; Rathee, D.; Razazi, V.; Read, K. F.; Real, J. S.; Redlich, K.; Reed, R. J.; Rehman, A.; Reichelt, P.; Reicher, M.; Reidt, F.; Ren, X.; Renfordt, R.; Reolon, A. R.; Reshetin, A.; Rettig, F.; Revol, J.-P.; Reygers, K.; Riabov, V.; Ricci, R. A.; Richert, T.; Richter, M.; Riedler, P.; Riegler, W.; Riggi, F.; Ristea, C.; Rivetti, A.; Rocco, E.; Rodríguez Cahuantzi, M.; Rodriguez Manso, A.; Røed, K.; Rogochaya, E.; Rohr, D.; Röhrich, D.; Romita, R.; Ronchetti, F.; Ronflette, L.; Rosnet, P.; Rossi, A.; Roukoutakis, F.; Roy, A.; Roy, C.; Roy, P.; Rubio Montero, A. J.; Rui, R.; Russo, R.; Ryabinkin, E.; Ryabov, Y.; Rybicki, A.; Sadovsky, S.; Šafařík, K.; Sahlmuller, B.; Sahoo, P.; Sahoo, R.; Sahoo, S.; Sahu, P. K.; Saini, J.; Sakai, S.; Saleh, M. A.; Salgado, C. A.; Salzwedel, J.; Sambyal, S.; Samsonov, V.; Sanchez Castro, X.; Šándor, L.; Sandoval, A.; Sano, M.; Santagati, G.; Sarkar, D.; Scapparone, E.; Scarlassara, F.; Scharenberg, R. P.; Schiaua, C.; Schicker, R.; Schmidt, C.; Schmidt, H. R.; Schuchmann, S.; Schukraft, J.; Schulc, M.; Schuster, T.; Schutz, Y.; Schwarz, K.; Schweda, K.; Scioli, G.; Scomparin, E.; Scott, R.; Seeder, K. S.; Seger, J. E.; Sekiguchi, Y.; Selyuzhenkov, I.; Senosi, K.; Seo, J.; Serradilla, E.; Sevcenco, A.; Shabanov, A.; Shabetai, A.; Shadura, O.; Shahoyan, R.; Shangaraev, A.; Sharma, A.; Sharma, M.; Sharma, N.; Shigaki, K.; Shtejer, K.; Sibiriak, Y.; Siddhanta, S.; Sielewicz, K. M.; Siemiarczuk, T.; Silvermyr, D.; Silvestre, C.; Simatovic, G.; Simonetti, G.; Singaraju, R.; Singh, R.; Singha, S.; Singhal, V.; Sinha, B. C.; Sinha, T.; Sitar, B.; Sitta, M.; Skaali, T. B.; Slupecki, M.; Smirnov, N.; Snellings, R. J. M.; Snellman, T. W.; Søgaard, C.; Soltz, R.; Song, J.; Song, M.; Song, Z.; Soramel, F.; Sorensen, S.; Spacek, M.; Spiriti, E.; Sputowska, I.; Spyropoulou-Stassinaki, M.; Srivastava, B. K.; Stachel, J.; Stan, I.; Stefanek, G.; Steinpreis, M.; Stenlund, E.; Steyn, G.; Stiller, J. H.; Stocco, D.; Strmen, P.; Suaide, A. A. P.; Sugitate, T.; Suire, C.; Suleymanov, M.; Sultanov, R.; Šumbera, M.; Symons, T. J. M.; Szabo, A.; Szanto de Toledo, A.; Szarka, I.; Szczepankiewicz, A.; Szymanski, M.; Takahashi, J.; Tanaka, N.; Tangaro, M. A.; Tapia Takaki, J. D.; Tarantola Peloni, A.; Tariq, M.; Tarzila, M. G.; Tauro, A.; Tejeda Muñoz, G.; Telesca, A.; Terasaki, K.; Terrevoli, C.; Teyssier, B.; Thäder, J.; Thomas, D.; Tieulent, R.; Timmins, A. R.; Toia, A.; Trogolo, S.; Trubnikov, V.; Trzaska, W. H.; Tsuji, T.; Tumkin, A.; Turrisi, R.; Tveter, T. S.; Ullaland, K.; Uras, A.; Usai, G. L.; Utrobicic, A.; Vajzer, M.; Vala, M.; Valencia Palomo, L.; Vallero, S.; van der Maarel, J.; van Hoorne, J. W.; van Leeuwen, M.; Vanat, T.; Vande Vyvre, P.; Varga, D.; Vargas, A.; Vargyas, M.; Varma, R.; Vasileiou, M.; Vasiliev, A.; Vauthier, A.; Vechernin, V.; Veen, A. M.; Veldhoen, M.; Velure, A.; Venaruzzo, M.; Vercellin, E.; Vergara Limón, S.; Vernet, R.; Verweij, M.; Vickovic, L.; Viesti, G.; Viinikainen, J.; Vilakazi, Z.; Villalobos Baillie, O.; Villatoro Tello, A.; Vinogradov, A.; Vinogradov, L.; Vinogradov, Y.; Virgili, T.; Vislavicius, V.; Viyogi, Y. P.; Vodopyanov, A.; Völkl, M. A.; Voloshin, K.; Voloshin, S. A.; Volpe, G.; von Haller, B.; Vorobyev, I.; Vranic, D.; Vrláková, J.; Vulpescu, B.; Vyushin, A.; Wagner, B.; Wagner, J.; Wang, H.; Wang, M.; Wang, Y.; Watanabe, D.; Weber, M.; Weber, S. G.; Wessels, J. P.; Westerhoff, U.; Wiechula, J.; Wikne, J.; Wilde, M.; Wilk, G.; Wilkinson, J.; Williams, M. C. S.; Windelband, B.; Winn, M.; Yaldo, C. G.; Yamaguchi, Y.; Yang, H.; Yang, P.; Yano, S.; Yasnopolskiy, S.; Yin, Z.; Yokoyama, H.; Yoo, I.-K.; Yurchenko, V.; Yushmanov, I.; Zaborowska, A.; Zaccolo, V.; Zaman, A.; Zampolli, C.; Zanoli, H. J. C.; Zaporozhets, S.; Zarochentsev, A.; Závada, P.; Zaviyalov, N.; Zbroszczyk, H.; Zgura, I. S.; Zhalov, M.; Zhang, H.; Zhang, X.; Zhang, Y.; Zhao, C.; Zhigareva, N.; Zhou, D.; Zhou, Y.; Zhou, Z.; Zhu, H.; Zhu, J.; Zhu, X.; Zichichi, A.; Zimmermann, A.; Zimmermann, M. B.; Zinovjev, G.; Zyzak, M.
2015-10-01
The measurement of the mass differences for systems bound by the strong force has reached a very high precision with protons and anti-protons. The extension of such measurement from (anti-)baryons to (anti-)nuclei allows one to probe any difference in the interactions between nucleons and anti-nucleons encoded in the (anti-)nuclei masses. This force is a remnant of the underlying strong interaction among quarks and gluons and can be described by effective theories, but cannot yet be directly derived from quantum chromodynamics. Here we report a measurement of the difference between the ratios of the mass and charge of deuterons (d) and anti-deuterons (), and 3He and nuclei carried out with the ALICE (A Large Ion Collider Experiment) detector in Pb-Pb collisions at a centre-of-mass energy per nucleon pair of 2.76 TeV. Our direct measurement of the mass-over-charge differences confirms CPT invariance to an unprecedented precision in the sector of light nuclei. This fundamental symmetry of nature, which exchanges particles with anti-particles, implies that all physics laws are the same under the simultaneous reversal of charge(s) (charge conjugation C), reflection of spatial coordinates (parity transformation P) and time inversion (T).
Precision measurement of the mass difference between light nuclei and anti-nuclei
Adam, J.
2015-08-17
The measurement of the mass differences for systems bound by the strong force has reached a very high precision with protons and anti-protons. The extension of such measurement from (anti-)baryons to (anti-)nuclei allows one to probe any difference in the interactions between nucleons and anti-nucleons encoded in the (anti-)nuclei masses. Also, this force is a remnant of the underlying strong interaction among quarks and gluons and can be described by effective theories, but cannot yet be directly derived from quantum chromodynamics. Here we report a measurement of the difference between the ratios of the mass and charge of deuterons (d) and anti-deuterons ($-\\atop{d}$), and ^{3}He and ^{3}$-\\atop{He}$nuclei carried out with the ALICE (A Large Ion Collider Experiment) detector in Pb–Pb collisions at a centre-of-mass energy per nucleon pair of 2.76 TeV. Our direct measurement of the mass-over-charge differences confirms CPT invariance to an unprecedented precision in the sector of light nuclei. This fundamental symmetry of nature, which exchanges particles with anti-particles, implies that all physics laws are the same under the simultaneous reversal of charge(s) (charge conjugation C), reflection of spatial coordinates (parity transformation P) and time inversion (T).
Backbending phenomena in light nuclei at A{approx}60
El-Kameesy, S. U.; Alharbi, H. H.; Alhendi, H. A.
2006-04-26
Recent studies of the backbending phenomenon in medium light weight nuclei near A{approx} 60 expanded greatly our interest about how the single particle orbits are nonlinearly affected by the collective motion. As a consequence we have applied a modified version of the exponential model in mass region at A {approx} 60. A firm conclusion is obtained concerning the successful validity of the proposed modified model in describing the backbending phenomenon in this region. Comparison with different theoretical descriptions is discussed.
Momentum distributions in light halo nuclei and structure constraints
NASA Astrophysics Data System (ADS)
Souza, L. A.; Bellotti, F. F.; Frederico, T.; Yamashita, M. T.; Tomio, Lauro
2016-03-01
The core recoil momentum distribution of neutron-rich isotopes of light exotic nuclei is studied within a three-body model, where the nuclei are described by a core and two neutrons, with interactions dominated by the s-wave channel. In our framework, the two-body subsystems should have large scattering lengths in comparison with the interaction range allowing to use a three-body model with a zero-range force. The ground-state halo wave functions in momentum space are obtained by using as inputs the two-neutron separation energy and the energies of the singlet neutron-neutron and neutron-core virtual states. Within our model, we obtain the momentum probability densities for the Borromean exotic nuclei 11Li and 22C. In the case of the core recoil momentum distribution of 11Li, a fair reproduction of the experimental data was obtained, without free parameters, considering only the two-body low-energies. By analysing the obtained core momentum distribution in face of recent experimental data, we verify that such data are constraining the 22C two-neutron separation energy to a value between 100 and 400 keV.
Light radioactive nuclei capture reactions with phenomenological potential models
Guimaraes, V.; Bertulani, C. A.
2010-05-21
Light radioactive nuclei play an important role in many astrophysical environments. Due to very low cross sections of some neutron and proton capture reactions by these radioactive nuclei at energies of astrophysical interest, direct laboratory measurements are very difficult. For radioactive nuclei such as {sup 8}Li and {sup 8}B, the direct measurement of neutron capture reactions is impossible. Indirect methods have been applied to overcome these difficulties. In this work we will report on the results and discussion of phenomenological potential models used to determine some proton and neutron capture reactions. As a test we show the results for the {sup 16}O(p,gamma){sup 17}F{sub gs}(5/2{sup +}) and {sup 16}O(p,gamma){sup 17}F{sub ex}(1/2{sup +}) capture reactions. We also computed the nucleosynthesis cross sections for the {sup 7}Li(n,gamma){sup 8}Li{sub gs}, {sup 8}Li(n,gamma){sup 9}Li{sub gs} and {sup 8}B(p,gamma){sup 9}C{sub gs} capture reactions.
Collective modes in light nuclei from first principles.
Dytrych, T; Launey, K D; Draayer, J P; Maris, P; Vary, J P; Saule, E; Catalyurek, U; Sosonkina, M; Langr, D; Caprio, M A
2013-12-20
Results for ab initio no-core shell model calculations in a symmetry-adapted SU(3)-based coupling scheme demonstrate that collective modes in light nuclei emerge from first principles. The low-lying states of 6Li, 8Be, and 6He are shown to exhibit orderly patterns that favor spatial configurations with strong quadrupole deformation and complementary low intrinsic spin values, a picture that is consistent with the nuclear symplectic model. The results also suggest a pragmatic path forward to accommodate deformation-driven collective features in ab initio analyses when they dominate the nuclear landscape.
Strictly finite-range potential for light and heavy nuclei
NASA Astrophysics Data System (ADS)
Salamon, P.; Lovas, R. G.; Betan, R. M. Id; Vertse, T.; Balkay, L.
2014-05-01
Strictly finite-range (SFR) potentials are exactly zero beyond their finite range. Single-particle energies and densities, as well as S-matrix pole trajectories, are studied in a few SFR potentials suited for the description of neutrons interacting with light and heavy nuclei. The SFR potentials considered are the standard cutoff Woods-Saxon (CWS) potentials and two potentials approaching zero smoothly: the SV potential introduced by Salamon and Vertse [Phys. Rev. C 77, 037302 (2008), 10.1103/PhysRevC.77.037302] and the SS potential of Sahu and Sahu [Int. J. Mod. Phys. E 21, 1250067 (2012), 10.1142/S021830131250067X]. The parameters of these latter potentials were set so that the potentials may be similar to the CWS shape. The range of the SV and SS potentials scales with the cube root of the mass number of the core like the nuclear radius itself. For light nuclei a single term of the SV potential (with a single parameter) is enough for a good description of the neutron-nucleus interaction. The trajectories are compared with a benchmark for which the starting points (belonging to potential depth zero) can be determined independently. Even the CWS potential is found to conform to this benchmark if the range is identified with the cutoff radius. For the CWS potentials some trajectories show irregular shapes, while for the SV and SS potentials all trajectories behave regularly.
One- and two neutron decay of light neutron-rich nuclei
NASA Astrophysics Data System (ADS)
Thoennessen, Michael
2014-09-01
Direct reactions with radioactive beams have been used very successfully to populate and measure nuclei beyond the neutron dripline and neutron unbound excited states of nuclei close to the neutron dripline. The use of different reactions (for example neutron removal and proton removal) to populate the same final nucleus can be used to selectively populate different states. Recent results from the MoNA-LISA setup at the NSCL, including 10He, 10,11Li, and 12,13Be will be presented. Direct reactions with radioactive beams have been used very successfully to populate and measure nuclei beyond the neutron dripline and neutron unbound excited states of nuclei close to the neutron dripline. The use of different reactions (for example neutron removal and proton removal) to populate the same final nucleus can be used to selectively populate different states. Recent results from the MoNA-LISA setup at the NSCL, including 10He, 10,11Li, and 12,13Be will be presented. This work was supported in part by the NSF, Grant PHY-11-02511.
Ab initio calculations of reactions of light nuclei
NASA Astrophysics Data System (ADS)
Hupin, Guillaume; Quaglioni, Sofia; Navrátil, Petr
2017-09-01
An ab initio (i.e., from first principles) theoretical framework capable of providing a unified description of the structure and low-energy reaction properties of light nuclei is desirable as a support tool for accurate evaluations of crucial reaction data for nuclear astrophysics, fusion-energy research, and other applications. We present an efficient many-body approach to nuclear bound and scattering states alike, known as the ab initio no-core shell model with continuum. In this approach, square-integrable energy eigenstates of the A-nucleon system are coupled to (A-A)+A target-plus-projectile wave functions in the spirit of the resonating group method to obtain an efficient description of the many-body nuclear dynamics both at short and medium distances and at long ranges. We show that predictive results for nucleon and deuterium scattering on 4He nuclei can be obtained from the direct solution of the Schröedinger equation with modern nuclear potentials.
Ab initio theories for light nuclei and neutron stars
NASA Astrophysics Data System (ADS)
Gezerlis, Alexandros
2016-09-01
In this talk I will touch upon several features of modern ab initio low-energy nuclear theory. I will start by discussing what ``ab initio'' means in this context. Specifically, I will spend some time going over nucleon-nucleon and three-nucleon interactions and their connections with the underlying theory of Quantum Chromodynamics. I will then show how these interactions are used to describe light nuclei using essentially exact few-body methods. I will then discuss heavier systems, especially those of astrophysical relevance, as well as the methods used to tackle them. This work was supported by the Natural Sciences and Engineering Research Council (NSERC) of Canada and the Canada Foundation for Innovation (CFI).
Mukha, I.; Suemmerer, K.; Chatillon, A.; Geissel, H.; Hofmann, J.; Kurz, N.; Nociforo, C.; Ott, W.; Roeckl, E.; Weick, H.; Acosta, L.; Garcia-Ramos, J. E.; Martel, I.; Alvarez, M. A. G.; Espino, J. M.; Gomez-Camacho, J.; Casarejos, E.; Cortina-Gil, D.; Egorova, I. A.; Fomichev, A.
2010-11-15
A powerful method of investigating proton-unbound nuclear states by tracking their decay products in flight is discussed in detail. To verify the method, four known levels in {sup 15}F, {sup 16}Ne, and {sup 19}Na were investigated by measuring the angular correlations between protons and the respective heavy-ion fragments stemming from the precursor decays in flight. The parent nuclei of interest were produced in nuclear reactions of one-neutron removal from {sup 17}Ne and {sup 20}Mg projectiles at energies of 410-450 A MeV. The trajectories of the respective decay products, {sup 14}O + p + p and {sup 18}Ne + p + p, were measured by applying a tracking technique with microstrip detectors. These data were used to reconstruct the angular correlations of the fragments, which provided information on energies and widths of the parent states. In addition for reproducing properties of known states, evidence for hitherto unknown excited states in {sup 15}F and {sup 16}Ne was found. This tracking technique has an advantage in studies of exotic nuclei beyond the proton drip line measuring the resonance energies and widths with a high precision although by using low-intensity beams and very thick targets.
Systematics of light nuclei in a relativistic model
Price, C.E.
1988-01-01
The results of relativistic mean field calculations for non-spherical nuclei are presented and discussed. The need for non-linear scalar meson self-couplings in order to describe the properties of s-d shell nuclei is emphasized along with the importance of self-consistency in calculations of magnetic moments of odd-mass nuclei. 16 refs., 3 figs., 2 tabs.
A new non-microscopic study of cluster structures in light alpha-conjugate nuclei
NASA Astrophysics Data System (ADS)
Zoghi-Foumani, Niloufar; Shojaei, Mohammad Reza; Rajabi, Ali Akbar
2017-01-01
In this paper, the alpha-cluster state in light alpha-conjugate nuclei is studied and a new suitable local potential model for the α-cluster phase of these nuclei is suggested. Using the generalized Nikiforov-Uvarov (NU) method, the clusterization energy for 8Be, 12C, 16O and 20Ne nuclei is calculated. Based on the obtained results, the clustering phenomenon is more probable at energies among excited levels and it happens neither at ground state nor at excited states of light alpha-conjugate nuclei. It is found that the presented formulation for clustering phenomenon reproduces the results of previous experimental and theoretical attempts for the mentioned nuclei. The consistency of the obtained results with the previous experimental and theoretical predictions indicates the reliability of this formulation for various types of alpha-conjugate, nuclei.
MCNP6 Simulation of Light and Medium Nuclei Fragmentation at Intermediate Energies
Mashnik, Stepan Georgievich; Kerby, Leslie Marie
2015-08-24
Fragmentation reactions induced on light and medium nuclei by protons and light nuclei of energies around 1 GeV/nucleon and below are studied with the Los Alamos transport code MCNP6 and with its CEM03.03 and LAQGSM03.03 event generators. CEM and LAQGSM assume that intermediate-energy fragmentation reactions on light nuclei occur generally in two stages. The first stage is the intranuclear cascade (INC), followed by the second, Fermi breakup disintegration of light excited residual nuclei produced after the INC. CEM and LAQGSM account also for coalescence of light fragments (complex particles) up to sup>4He from energetic nucleons emitted during INC. We investigate the validity and performance of MCNP6, CEM, and LAQGSM in simulating fragmentation reactions at intermediate energies and discuss possible ways of further improving these codes.
Systematics of proton and diproton separation energies for light nuclei
Cole, B.J.
1997-10-01
A simple method to estimate proton and two-proton separation energies of proton-rich nuclei is presented that is sufficiently accurate to allow the prediction of suitable candidates for observable diproton decay. The method is based on the systematics of measured particle separation energies. Predictions for proton-rich nuclei with Z=18{minus}24 are compared with the results of previous calculations. {copyright} {ital 1997} {ital The American Physical Society}
Structure and reactions of light neutron rich nuclei
Esbensen, H.
1993-01-01
Radioactive beam experiments have made it possible to study the structure of nuclei at the neutron drip line. Pair correlations play a crucial role in such nuclei and characteristic features include an extended neutron halo density and a large dipole strength near threshold. The most detailed studies have been performed for [sup 11]Li. I will present a 3-body model that explains the main features of the data obtained for this nucleus.
Structure and reactions of light neutron rich nuclei
Esbensen, H.
1993-04-01
Radioactive beam experiments have made it possible to study the structure of nuclei at the neutron drip line. Pair correlations play a crucial role in such nuclei and characteristic features include an extended neutron halo density and a large dipole strength near threshold. The most detailed studies have been performed for {sup 11}Li. I will present a 3-body model that explains the main features of the data obtained for this nucleus.
Magnetic structure of light nuclei from lattice QCD
Chang, Emmanuel; Detmold, William; Orginos, Kostas; Parreño, Assumpta; Savage, Martin J.; Tiburzi, Brian C.; Beane, Silas R.
2015-12-09
Lattice QCD with background magnetic fields is used to calculate the magnetic moments and magnetic polarizabilities of the nucleons and of light nuclei with $A\\le4$, along with the cross-section for the $M1$ transition $np\\rightarrow d\\gamma$, at the flavor SU(3)-symmetric point where the pion mass is $m_\\pi\\sim 806$ MeV. These magnetic properties are extracted from nucleon and nuclear energies in six uniform magnetic fields of varying strengths. The magnetic moments are presented in a recent Letter. For the charged states, the extraction of the polarizability requires careful treatment of Landau levels, which enter non-trivially in the method that is employed. The nucleon polarizabilities are found to be of similar magnitude to their physical values, with $\\beta_p=5.22(+0.66/-0.45)(0.23) \\times 10^{-4}$ fm$^3$ and $\\beta_n=1.253(+0.056/-0.067)(0.055) \\times 10^{-4}$ fm$^3$, exhibiting a significant isovector component. The dineutron is bound at these heavy quark masses and its magnetic polarizability, $\\beta_{nn}=1.872(+0.121/-0.113)(0.082) \\times 10^{-4}$ fm$^3$ differs significantly from twice that of the neutron. A linear combination of deuteron scalar and tensor polarizabilities is determined by the energies of the $j_z=\\pm 1$ deuteron states, and is found to be $\\beta_{d,\\pm 1}=4.4(+1.6/-1.5)(0.2) \\times 10^{-4}$ fm$^3$. The magnetic polarizabilities of the three-nucleon and four-nucleon systems are found to be positive and similar in size to those of the proton, $\\beta_{^{3}\\rm He}=5.4(+2.2/-2.1)(0.2) \\times 10^{-4}$ fm$^3$, $\\beta_{^{3}\\rm H}=2.6(1.7)(0.1) \\times 10^{-4}$ fm$^3$, $\\beta_{^{4}\\rm He}=3.4(+2.0/-1.9)(0.2) \\times 10^{-4}$ fm$^3$. Mixing between the $j_z=0$ deuteron state and the spin-singlet $np$ state induced by the background magnetic field is used to extract the short-distance two-nucleon counterterm, ${\\bar L}_1$, of the pionless effective theory for $NN$ systems (equivalent to the meson-exchange current
Magnetic structure of light nuclei from lattice QCD
Chang, Emmanuel; Detmold, William; Orginos, Kostas; ...
2015-12-09
Lattice QCD with background magnetic fields is used to calculate the magnetic moments and magnetic polarizabilities of the nucleons and of light nuclei withmore » $$A\\le4$$, along with the cross-section for the $M1$ transition $$np\\rightarrow d\\gamma$$, at the flavor SU(3)-symmetric point where the pion mass is $$m_\\pi\\sim 806$$ MeV. These magnetic properties are extracted from nucleon and nuclear energies in six uniform magnetic fields of varying strengths. The magnetic moments are presented in a recent Letter. For the charged states, the extraction of the polarizability requires careful treatment of Landau levels, which enter non-trivially in the method that is employed. The nucleon polarizabilities are found to be of similar magnitude to their physical values, with $$\\beta_p=5.22(+0.66/-0.45)(0.23) \\times 10^{-4}$$ fm$^3$ and $$\\beta_n=1.253(+0.056/-0.067)(0.055) \\times 10^{-4}$$ fm$^3$, exhibiting a significant isovector component. The dineutron is bound at these heavy quark masses and its magnetic polarizability, $$\\beta_{nn}=1.872(+0.121/-0.113)(0.082) \\times 10^{-4}$$ fm$^3$ differs significantly from twice that of the neutron. A linear combination of deuteron scalar and tensor polarizabilities is determined by the energies of the $$j_z=\\pm 1$$ deuteron states, and is found to be $$\\beta_{d,\\pm 1}=4.4(+1.6/-1.5)(0.2) \\times 10^{-4}$$ fm$^3$. The magnetic polarizabilities of the three-nucleon and four-nucleon systems are found to be positive and similar in size to those of the proton, $$\\beta_{^{3}\\rm He}=5.4(+2.2/-2.1)(0.2) \\times 10^{-4}$$ fm$^3$, $$\\beta_{^{3}\\rm H}=2.6(1.7)(0.1) \\times 10^{-4}$$ fm$^3$, $$\\beta_{^{4}\\rm He}=3.4(+2.0/-1.9)(0.2) \\times 10^{-4}$$ fm$^3$. Mixing between the $$j_z=0$$ deuteron state and the spin-singlet $np$ state induced by the background magnetic field is used to extract the short-distance two-nucleon counterterm, $${\\bar L}_1$$, of the pionless effective theory for $NN$ systems (equivalent to the
N3LO NN interaction adjusted to light nuclei in ab exitu approach
Shirokov, A. M.; Shin, I. J.; Kim, Y.; ...
2016-08-09
Here, we use phase-equivalent transformations to adjust off-shell properties of similarity renormalization group evolved chiral effective field theory NN interaction (Idaho N3LO) to fit selected binding energies and spectra of light nuclei in an ab exitu approach. Then, we test the transformed interaction on a set of additional observables in light nuclei to verify that it provides reasonable descriptions of these observables with an apparent reduced need for three- and many-nucleon interactions.
Unstable nuclei in dissociation of light stable and radioactive nuclei in nuclear track emulsion
NASA Astrophysics Data System (ADS)
Artemenkov, D. A.; Zaitsev, A. A.; Zarubin, P. I.
2017-01-01
A role of the unstable nuclei 6Be, 8Be and 9B in the dissociation of relativistic nuclei 7,9Be, 10B and 10,11C is under study on the basis of nuclear track emulsion exposed to secondary beams of the JINR Nuclotron. Contribution of the configuration 6Be + n to the 7Be nucleus structure is 8 ± 1% which is near the value for the configuration 6Li + p. Distributions over the opening angle of α-particle pairs indicate to a simultaneous presence of virtual 8Beg.s. and 8Be2+ states in the ground states of the 9Be and 10C nuclei. The core 9B is manifested in the 10C nucleus with a probability of 30 ± 4%. Selection of the 10C "white" stars accompanied by 8Beg.s. (9B) leads to appearance in the excitation energy distribution of 2α2 p "quartets" of the distinct peak with a maximum at 4.1 ± 0.3 MeV. 8Beg.s. decays are presented in 24 ± 7% of 2He + 2H events of the 11C coherent dissociation and 27 ± 11% of the 3He ones. The channel 9B + H amounts 14 ± 3%. The 8Bg.s. nucleus is manifested in the coherent dissociation 10B → 2He + H with a probability of 25 ± 5% including 13 ± 3% of 9B decays. A probability ratio of the mirror channels 9B + n and 9Be + p is estimated to be 10 ± 1.
Magnetic moments of light nuclei from lattice quantum chromodynamics
Beane, S. R.; Chang, E.; Cohen, S.; ...
2014-12-16
We present the results of lattice QCD calculations of the magnetic moments of the lightest nuclei, the deuteron, the triton and 3He, along with those of the neutron and proton. These calculations, performed at quark masses corresponding to mπ ~ 800 MeV, reveal that the structure of these nuclei at unphysically heavy quark masses closely resembles that at the physical quark masses. We find that the magnetic moment of 3He differs only slightly from that of a free neutron, as is the case in nature, indicating that the shell-model configuration of two spin-paired protons and a valence neutron captures itsmore » dominant structure. Similarly a shell-model-like moment is found for the triton, μ3H ~ μp. The deuteron magnetic moment is found to be equal to the nucleon isoscalar moment within the uncertainties of the calculations.« less
The study of initial conditions in collisions of light, intermediate and heavy nuclei
NASA Astrophysics Data System (ADS)
Loctionov, A. A.; Arginova, A. Kh.; Gaitinov, A. Sh.; Kvochkina, T. N.
2017-06-01
The system size dependence for multiparticle processes has been recognized in both cosmic ray ("Stratosphere" collaboration) and at accelerator ("EMU" collaboration) experiments. The strong enhancement in multiplicity fluctuations for the most central light-light - (C, O, Ne) + (C/N/O) - collisions has been revealed at JINR-AGS-SPS energies. The sharp difference of light nuclear interactions are interpreted as the sign of intrinsic alpha-clustering in light nuclei.
Fu, Jinling; Fang, Wei; Zou, Jian; Sun, Ming; Lathrop, Kira; Su, Guanfang; Wei, Xiangyun
2013-03-01
To simultaneously visualize individual cell nuclei and tissue morphologies of the zebrafish retina under bright field light microscopy, it is necessary to establish a procedure that specifically and sensitively stains the cell nuclei in thin tissue sections. This necessity arises from the high nuclear density of the retina and the highly decondensed chromatin of the cone photoreceptors, which significantly reduces their nuclear signals and makes nuclei difficult to distinguish from possible high cytoplasmic background staining. Here we optimized a procedure that integrates JB4 plastic embedding and Feulgen reaction for visualizing zebrafish retinal cell nuclei under bright field light microscopy. This method produced highly specific nuclear staining with minimal cytoplasmic background, allowing us to distinguish individual retinal nuclei despite their tight packaging. The nuclear staining is also sensitive enough to distinguish the euchromatin from heterochromatin in the zebrafish cone nuclei. In addition, this method could be combined with in situ hybridization to simultaneously visualize the cell nuclei and mRNA expression patterns. With its superb specificity and sensitivity, this method may be extended to quantify cell density and analyze global chromatin organization throughout the retina or other tissues.
Fu, Jinling; Fang, Wei; Zou, Jian; Sun, Ming; Lathrop, Kira; Su, Guanfang
2013-01-01
To simultaneously visualize individual cell nuclei and tissue morphologies of the zebrafish retina under bright field light microscopy, it is necessary to establish a procedure that specifically and sensitively stains the cell nuclei in thin tissue sections. This necessity arises from the high nuclear density of the retina and the highly decondensed chromatin of the cone photoreceptors, which significantly reduces their nuclear signals and makes nuclei difficult to distinguish from possible high cytoplasmic background staining. Here we optimized a procedure that integrates JB4 plastic embedding and Feulgen reaction for visualizing zebrafish retinal cell nuclei under bright field light microscopy. This method produced highly specific nuclear staining with minimal cytoplasmic background, allowing us to distinguish individual retinal nuclei despite their tight packaging. The nuclear staining is also sensitive enough to distinguish the euchromatin from heterochromatin in the zebrafish cone nuclei. In addition, this method could be combined with in situ hybridization to simultaneously visualize the cell nuclei and mRNA expression patterns. With its superb specificity and sensitivity, this method may be extended to quantify cell density and analyze global chromatin organization throughout the retina or other tissues. PMID:23204114
Fragmentation of light nuclei by intermediate energy photons
NASA Astrophysics Data System (ADS)
Turinge, A. A.; Lapik, A. M.; Mushkarenkov, A. N.; Nedorezov, V. G.; Rudnev, N. V.
2017-01-01
New data on the fragmentation of carbon nuclei by photons with energies from 800 to 1500 MeV, obtained in the collaboration GRAAL, are presented. These data include the yields of heavier fragments than nucleons. Comparison of new results with literature data, obtained with real and virtual photons in reactions with electrons and relativistic ions (Coulomb dissociation) is done using a general approach in frame of the Weizsäcker-Williams model. Possible reasons for the observed differences between them are discussed.
Effects of Distortion on the Intercluster Motion in Light Nuclei
Pizzone, R. G.; Spitaleri, C.; Cherubini, S.; La Cognata, M.; Lamia, L.; Romano, S.; Bertulani, C.; Mukhamedzhanov, A.; Blokhintsev, L.; Irgaziev, B.; Miljanic, D.; Tumino, A.
2009-08-26
Deuteron induced quasi-free scattering and reactions have been extensively investigated in the past few decades as well as {sup 6}Li, {sup 3}He and {sup 9}Be induced ones. This was done not only for nuclear structure and processes study but also for the important astrophysical implication (Trojan Horse Method, THM). In particular the width of the spectator momentum distribution in {sup 6}Li and deuterium, which have widely been used as a Trojan Horse nuclei, will be studied as a function of the transferred momentum. Trojan horse method applications will also be discussed in these cases.
Structure of Light Neutron-rich Nuclei Studied with Transfer Reactions
Wuosmaa, A. H.
2015-01-01
Transfer reactions have been used for many years to understand the shell structure of nuclei. Recent studies with rare-isotope beams extend this work and make it possible to probe the evolution of shell structure far beyond the valley of stability, requiring measurements in inverse kinematics. We present a novel technical approach to measurements in inverse kinematics, and apply this method to different transfer reactions, each of which probes different properties of light, neutron-rich nuclei.
Light exotic nuclei with extreme neutron excess and 2 ≤ Z ≤ 8
NASA Astrophysics Data System (ADS)
Tarasov, V. N.; Gridnev, K. A.; Schramm, S.; Kuprikov, V. I.; Gridnev, D. K.; Tarasov, D. V.; Godbey, K. S.; Viñas, X.; Greiner, Walter
2015-07-01
Using HF + BCS method we study light nuclei with nuclear charge in the range 2 ≤ Z ≤ 8 and lying near the neutron drip line. The HF method uses effective Skyrme forces and allows for axial deformations. We find that the neutron drip line forms stability peninsulas at 18He and 40C. These isotopes are found to be stable against one neutron emission and possess the highest known neutron to proton ratio in stable nuclei.
Magnetic moments of light nuclei from lattice quantum chromodynamics
Beane, S. R.; Chang, E.; Cohen, S.; Detmold, W.; Lin, H. W.; Orginos, K.; Parreño, A.; Savage, M. J.; Tiburzi, B. C.
2014-12-16
We present the results of lattice QCD calculations of the magnetic moments of the lightest nuclei, the deuteron, the triton and ^{3}He, along with those of the neutron and proton. These calculations, performed at quark masses corresponding to m_{π} ~ 800 MeV, reveal that the structure of these nuclei at unphysically heavy quark masses closely resembles that at the physical quark masses. We find that the magnetic moment of ^{3}He differs only slightly from that of a free neutron, as is the case in nature, indicating that the shell-model configuration of two spin-paired protons and a valence neutron captures its dominant structure. Similarly a shell-model-like moment is found for the triton, μ_{3H} ~ μ_{p}. The deuteron magnetic moment is found to be equal to the nucleon isoscalar moment within the uncertainties of the calculations.
Statistical theory of light nucleus reactions with 1p-shell light nuclei
NASA Astrophysics Data System (ADS)
Xiaojun, Sun; Jingshang, Zhang
2017-09-01
The 1p-shell light elements (Li, Be, B, C, N, and O) had long been selected as the most important materials for improving neutron economy in thermal and fast fission reactors and in the design of accelerator-driven spallation neutron sources. A statistical theory of light nucleus reactions (STLN) is proposed to describe the double-differential cross sections for both neutron and light charged particle induced nuclear reactions with 1p-shell light nuclei. The dynamics of STLN is described by the unified Hauser-Feshbach and exciton model, in which the angular momentum and parity conservations are strictly considered in equilibrium and pre-equilibrium processes. The Coulomb barriers of the incoming and outgoing charged particles, which significantly influence the open channels of the reaction, can be reasonably considered in incident channel and different outgoing channels. In kinematics, the recoiling effects in various emission processes are strictly taken into account. The analytical energy and angular spectra of the reaction products in sequential and simultaneous emission processes are obtained in terms of the new integral formula proposed in our recent paper. Taking 12C(n, xn), 9Be(n, xn), 16O(n, xn), and 9Be(p,xn) reactions as examples, we had calculated the double-differential cross sections of outgoing neutrons and compared with the experimental data. In addition, we had also calculated the partition and total kerma coefficients for 12C(n, xn) and 16O(n, xn) reactions, respectively. The existing experimental data can be remarkably well reproduced by STLN, which had been used to set up file-6 in CENDL database.
Study of multi-nucleon transfer reactions with light nuclei
Benzoni, G.; Montanari, D.; Bracco, A.; Blasi, N.; Camera, F.; Crespi, F. C. L.; Corsi, A.; Leoni, S.; Million, B.; Nicolini, R.; Wieland, O.; Zalite, A.; Zocca, F.; Azaiez, F.; Franchoo, S.; Stefan, I.; Ibrahim, F.; Verney, D.; Battacharyya, S.; De France, G.
2008-05-12
Multi-nucleon transfer reactions are useful tools to populate exotic nuclei, particularly the neutron-rich ones. In this view, two different experiments have been performed employing a stable ({sup 22}Ne) and a radioactive ({sup 24}Ne) beam, both impinging on a {sup 208}Pb target. The first reaction has been studied using the CLARA-PRISMA-DANTE set-up at Laboratori Nazionali di Legnaro (Legnaro-Italy), while the second reaction was performed at Ganil (Caen-France) employing a SPIRAL radioactive beam of {sup 24}Ne. In this case recoils and coincident {gamma} rays were detected with the VAMOS-EXOGAM set-up.The data show that MNT reactions can selectively populate states of different nature and, therefore, are a good tool to study nuclear structure further away from stability.
Amplitudes and overlaps in ab initio calculations of light nuclei
NASA Astrophysics Data System (ADS)
Nollett, Kenneth
2016-09-01
Some clustering properties of nuclei are usefully interpreted in terms of overlap functions. These functions are projections of an A-body nucleus onto an (A - 1) -body core and an additional nucleon, or an (A - 4) -body core and an additional alpha particle, at varying separation. Long-range limits of overlaps are given by asymptotic normalization constants (ANCs), which suffice to model some reaction processes; their shorter-range parts are also needed to interpret some types of experiments. Naively, one computes overlaps from wave functions using their definition. However, there is an integral relation that allows more accurate calculations from approximate wave functions, using exact terms from the nucleon-nucleon potential. I will describe calculations by this method of overlap functions and ANCs for both nucleon and alpha emission from ab initio variational Monte Carlo wave functions. I will also describe the use of overlaps to probe small components of wave functions like those arising from hadronic parity violation.
Deformed Brueckner-Hartree-Fock calculation for light nuclei
NASA Technical Reports Server (NTRS)
Braley, R. C.; Ford, W. F.; Becker, R. L.; Patterson, M. R.
1971-01-01
For the first time the Brueckner-Hartree-Fock (BHF) method was applied to nuclei whose intrinsic structure is nonspherical. One aim was to investigate whether the energy dependent reaction matrix calculated from a realistic nucleon-nucleon interaction leads to deformations similar to, or different from, those obtained from energy independent interactions in Hartree-Fock (HF) calculations. Reaction matrix elements were calculated as a function of starting energy for the Hamada-Johnston interaction, using a Pauli operator appropriate to O-16 and a shifted oscillator spectrum for virtual excited states. Binding energies, single-particle energies, radii, and shape deformations of the intrinsic state in unrenormalized as well as renormalized BHF are discussed and compared with previous HF studies. Results are presented for C-12, O-16, and Ne-20.
Axial-Current Matrix Elements in Light Nuclei from Lattice QCD
Savage, Martin; Shanahan, Phiala E.; Tiburzi, Brian C.; Wagman, Michael L.; Winter, Frank T.; Beane, Silas; Chang, Emmanuel; Davoudi, Zohreh; Detmold, William; Orginos, Konstantinos
2016-12-01
I present results from the first lattice QCD calculations of axial-current matrix elements in light nuclei, performed by the NPLQCD collaboration. Precision calculations of these matrix elements, and the subsequent extraction of multi-nucleon axial-current operators, are essential in refining theoretical predictions of the proton-proton fusion cross section, neutrino-nucleus cross sections and $\\beta\\beta$-decay rates of nuclei. In addition, they are expected to shed light on the phenomenological quenching of $g_A$ that is required in nuclear many-body calculations.
NASA Astrophysics Data System (ADS)
Röpke, G.
2011-10-01
Correlations and the formation of bound states (nuclei) are essential for the properties of nuclear matter in equilibrium as well as in nonequilibrium. In a quantum statistical approach, quasiparticle energies are obtained for the light elements that reflect the influence of the medium. We present analytical fits for the quasiparticle energy shifts of light nuclei that can be used in various applications. This is a prerequisite for the investigation of warm and dense matter that reproduces the nuclear statistical equilibrium and virial expansions in the low-density limit as well as relativistic mean field and Brueckner Hartree-Fock approaches near saturation density.
Iwabuchi, Kosei; Takagi, Shingo
2010-08-01
The plant organelles, chloroplast and nucleus, change their position in response to light. In Arabidopsis thaliana leaf cells, chloroplasts and nuclei are distributed along the inner periclinal wall in darkness. In strong blue light, they become positioned along the anticlinal wall, while in weak blue light, only chloroplasts are accumulated along the inner and outer periclinal walls. Blue-light dependent positioning of both organelles is mediated by the blue-light receptor phototropin and controlled by the actin cytoskeleton. Interestingly, however, it seems that chloroplast movement requires short, fine actin filaments organized at the chloroplast edge, whereas nuclear movement does cytoplasmic, thick actin bundles intimately associated with the nucleus. Although there are many similarities between photo-relocation movements of chloroplasts and nuclei, plant cells appear to have evolved distinct mechanisms to regulate actin organization required for driving the movements of these organelles.
Quantum Monte Carlo studies of relativistic effects in light nuclei
NASA Astrophysics Data System (ADS)
Forest, J. L.; Pandharipande, V. R.; Arriaga, A.
1999-07-01
Relativistic Hamiltonians are defined as the sum of relativistic one-body kinetic energy, two- and three-body potentials, and their boost corrections. In this work we use the variational Monte Carlo method to study two kinds of relativistic effects in 3H and 4He, using relativistic Hamiltonians. The first is due to the nonlocalities in the relativistic kinetic energy and relativistic one-pion exchange potential (OPEP), and the second is from boost interaction. The OPEP contribution is reduced by ~15% by the relativistic nonlocality, which may also have significant effects on pion exchange currents. However, almost all of this reduction is canceled by changes in the kinetic energy and other interaction terms, and the total effect of the nonlocalities on the binding energy is very small. The boost interactions, on the other hand, give repulsive contributions of ~0.4 (1.9) MeV in 3H (4He) and account for ~37% of the phenomenological part of the three-nucleon interaction needed in the nonrelativistic Hamiltonians. The wave functions of nuclei are not significantly changed by these effects.
Medium Modification of the Light Vector Mesons in Nuclei
Nasseripour, R.; Djalali, C.; Wood, M.; Weygand, D.
2008-10-13
Theoretical calculations predict the modification of properties of vector mesons, such as a shift in their masses and/or broadening of their widths in dense nuclear matter. These effects can be related to partial restoration of chiral symmetry at high density or temperature. Photoproduction of vector mesons off nuclei were performed at Jefferson Lab using the CEBAF Large Acceptance Spectrometer (CLAS). The data were taken with a beam of tagged photons with energies up to 4 GeV on various nuclear targets. The properties of the {rho} vector mesons were investigated via their rare leptonic decay to e+e{sup -}. This decay channel is preferred over hadronic modes in order to eliminate final state interactions in the nuclear matter. The combinatorial background in the mass spectrum was removed by a self-normalizing mixed-event technique. The {rho} meson mass distributions were extracted for each of the targets. Statistically significant results regarding medium modification of the rho meson in the nuclear medium rule out large medium effects. Transparency studies of the {omega} and {phi} vector mesons allows a determination of their widths in the medium.
Insulin-related signaling pathways elicited by light in photoreceptor nuclei from bovine retina.
Natalini, Paola M; Mateos, Melina V; Ilincheta de Boschero, Mónica G; Giusto, Norma M
2016-04-01
Retina light stimulation triggers phototransduction events as well as different signaling mechanisms in outer segments (sensorial portion) of photoreceptor cells. We have recently reported a novel light-dependent activation of diacylglycerol kinase (DAGK) and protein kinase C (PKC) at the nuclear level of photoreceptor cells. The aim of the present study was to analyze whether ex-vivo light exposure of bovine retinas also modulates insulin-related signaling pathways in nuclei from photoreceptor cells. To this end, a nuclear fraction enriched in small nuclei from photoreceptor cells (PNF) was obtained using a modified nuclear isolation protocol. In PNF obtained from bovine retinas exposed to light or darkness, the presence of insulin receptor (IR) and phosphorylated insulin receptor (pIR), the activation of Akt, p38 and extracellular signal-regulated kinase (ERK1/2) and the local action of insulin on lipid kinases were studied. Immunofluorescence (IF) and Western blot (WB) studies revealed the presence of IR in photoreceptor nuclei. In PNF a light-dependent increase in IR total content was observed. The presence of activated IR (pIR) was also observed in PNF by WB, being its content higher in PNF from light than in to darkness. Light exposure also produced a significant increase in the content of p-Akt (3 fold) and p-p38 (60%) without changes in total Akt and p38. In addition, an increase in the content of total ERK1/2 (2 fold) was found without changes in p-ERK/total ERK ratio, indicating that light induces translocation of p-ERK to the nucleus. Polyphosphoinositide kinase and diacylglycerol kinase (DAGK) activities were measured in isolated nuclei from light-activated or darkness-adapted retinas through the formation of polyphosphoinositides (PPIs) and phosphatidic acid (PA) using nuclear lipid substrates and [γ-(32)P]ATP as radioactive substrate. A light-dependent increase in PPIs and PA formation was detected when isolated nuclei were exposed to 0.8
(Multi-)strange hadron and light (anti-)nuclei production with ALICE at the LHC
Lea, Ramona
2016-01-22
Thanks to its excellent tracking performance and particle identification capabilities, the ALICE detector allows for the identification of light (anti-)(hyper)nuclei and for the measurement of (multi-)strange particles over a wide range of transverse momentum. Deuterons, {sup 3}He and {sup 4}He and their corresponding anti-nuclei are identified via their specific energy loss in the Time Projection Chamber and the velocity measurement provided by the Time-Of-Flight detector. Strange and multi-strange baryons and mesons as well as (anti-)hypertritons are reconstructed via their topological decays. Detailed measurements of (multi-)strange hadron production in pp, p–Pb and Pb–Pb collision and of light (anti-)nuclei and (anti-)hypertritons in Pb–Pb collisions with ALICE at the LHC are presented. The experimental results will be compared with the predictions of both statistical hadronization and coalescence models.
Light Nuclei and HyperNuclei from Quantum Chromodynamics in the Limit of SU(3) Flavor Symmetry
Beane, S R; Cohen, S D; Detmold, W; Lin, H W; Luu, T C; Orginos, K; Parreno, A; Savage, M J; Walker-Loud, A
2013-02-01
The binding energies of a range of nuclei and hypernuclei with atomic number A <= 4 and strangeness |s| <= 2, including the deuteron, di-neutron, H-dibaryon, {sup 3}He, {sub {Lambda}}{sup 3}He, {sub {Lambda}}{sup 4}He, and {sub {Lambda}{Lambda}}{sup 4}He, are calculated in the limit of flavor-SU(3) symmetry at the physical strange quark mass with quantum chromodynamics (without electromagnetic interactions). The nuclear states are extracted from Lattice QCD calculations performed with n{sub f}=3 dynamical light quarks using an isotropic clover discretization of the quark-action in three lattice volumes of spatial extent L ~ 3.4 fm, 4.5 fm and 6.7 fm, and with a single lattice spacing b ~ 0.145 fm.
NASA Technical Reports Server (NTRS)
George, M. C.
1972-01-01
Gamma-ray production cross section by the inelastic scattering of neutrons from light nuclei are considered. The applicability of optical model potential is discussed. Based on experimental data, a cascade approach is developed to calculate the inelastic gamma production cross sections. In the case of O-16 using computer code LINGAP in conjunction with ABACUS-2; results are compared with reported values.
Benchmark calculation of no-core Monte Carlo shell model in light nuclei
Abe, T.; Shimizu, N.; Maris, P.; Vary, J. P.; Otsuka, T.; Utsuno, Y.
2011-05-06
The Monte Carlo shell model is firstly applied to the calculation of the no-core shell model in light nuclei. The results are compared with those of the full configuration interaction. The agreements between them are within a few % at most.
NASA Astrophysics Data System (ADS)
Furusawa, S.; Nagakura, H.; Sumiyoshi, K.; Yamada, S.
2016-01-01
We perform numerical experiments to investigate the influence of inelastic neutrino reactions with light nuclei on the standing accretion shock instability. The time evolutions of shock waves are calculated with a simple light-bulb approximation for the neutrino transport and a multi-nuclei equation of state. The neutrino absorptions and inelastic interactions with deuterons, tritons, helions and alpha particles are taken into account in the hydrodynamical simulations in addition to the ordinary charged-current interactions with nucleons. Axial symmetry is assumed but no equatorial symmetry is imposed. We show that the heating rates of deuterons reach as high as ∼ 10% of those of nucleons around the bottom of the gain region. On the other hands, alpha particles heat the matter near the shock wave, which is important when the shock wave expands and density and temperature of matter become low. It is also found that the models with heating by light nuclei have different evolutions from those without it in non-linear evolution phase. The matter in the gain region has various densities and temperatures and there appear regions that are locally rich in deuterons and alpha particles. These results indicate that the inelastic reactions of light nuclei, especially deuterons, should be incorporated in the simulations of core-collapse supernovae.
Frequency of light-flashes induced by Cerenkov radiation from heavy cosmic-ray nuclei
NASA Technical Reports Server (NTRS)
Madey, R.; Mcnulty, P. J.
1972-01-01
The expected frequency was calculated for light flashes induced in the dark-adapted eye by Cerenkov radiation from the flux of heavy nuclei that exists in space beyond the geomagnetic field. The expected frequency of light flashes depends on the threshold number of photons that must be absorbed in a rod cluster. The results of the calculation are presented as a curve of the mean frequency of light flashes versus the threshold number of absorbed photons. The results are not sensitive to variations in the path length from 5 to 15 grams per square centimeter of water-equivalent before the nucleus reaches the retina. Calculations were based on the fluxes and energy spectra of galactic cosmic ray nuclei of helium to iron, measured at a time of minimum solar modulation. The expected light flash frequencies induced by Cerenkov radiation are consistent with the frequencies reported by the astronauts on Apollo missions 11 through 14.
NASA Astrophysics Data System (ADS)
Arifler, Dizem; MacAulay, Calum; Follen, Michele; Guillaud, Martial
2014-03-01
Dysplastic progression in epithelial tissues is linked to changes in morphology and internal structure of cell nuclei. These changes lead to alterations in nuclear light scattering profiles that can potentially be monitored for diagnostic purposes. Numerical tools allow for simulation of complex nuclear models and are particularly useful for quantifying the optical response of cell nuclei as dysplasia progresses. In this study, we first analyze a set of quantitative histopathology images from twenty cervical biopsy sections stained with Feulgen-thionin. Since Feulgen-thionin is stoichiometric for DNA, the images enable us to obtain detailed information on size, shape, and chromatin content of all the segmented nuclei. We use this extensive data set to construct realistic three-dimensional computational models of cervical cell nuclei that are representative of four diagnostic categories, namely normal or negative for dysplasia, mild dysplasia, moderate dysplasia, and severe dysplasia or carcinoma in situ (CIS). We then carry out finite-difference time-domain simulations to compute the light scattering response of the constructed models as a function of the polar scattering angle and the azimuthal scattering angle. The results show that these two-dimensional scattering patterns exhibit characteristic intensity ridges that change form with progression of dysplasia; pattern processing reveals that Haralick features can be used to distinguish moderately and severely dysplastic or CIS nuclei from normal and mildly dysplastic nuclei. Our numerical study also suggests that different angular ranges need to be considered separately to fully exploit the diagnostic potential of two-dimensional light scattering measurements.
Data Covariances from R-Matrix Analyses of Light Nuclei
Hale, G.M. Paris, M.W.
2015-01-15
After first reviewing the parametric description of light-element reactions in multichannel systems using R-matrix theory and features of the general LANL R-matrix analysis code EDA, we describe how its chi-square minimization procedure gives parameter covariances. This information is used, together with analytically calculated sensitivity derivatives, to obtain cross section covariances for all reactions included in the analysis by first-order error propagation. Examples are given of the covariances obtained for systems with few resonances ({sup 5}He) and with many resonances ({sup 13}C ). We discuss the prevalent problem of this method leading to cross section uncertainty estimates that are unreasonably small for large data sets. The answer to this problem appears to be using parameter confidence intervals in place of standard errors.
Measuring the Fusion Cross-Section of Light Nuclei with Low-Intensity Beams
NASA Astrophysics Data System (ADS)
Steinbach, Tracy; Brown, Kyle; Hudan, Sylvie; Desouza, Romualdo
2014-03-01
Reactions between neutron-rich light nuclei have been proposed as a heat source in the crust of an accreting neutron star that triggers an X-ray superburst. To explore the probability of such fusion events as well as better understand the fusion dynamics between neutron-rich nuclei, an experimental program to measure the dependence of the fusion cross-section on neutron number has been initiated. Key to these measurements is developing an approach to measure the total fusion cross-section for beams of low-intensity light nuclei (<105 ions/s) on light targets. Fusion residues resulting from the fusion of oxygen nuclei with 12C at energies near and below the Coulomb barrier are directly measured and distinguished from unreacted beam particles on the basis of their energy and time-of-flight (TOF). The TOF is measured between a microchannel plate (MCP) detector and a segmented Si detector. Two initial problems were charge trapping in the Si detector and slit scattering in the MCP detector. These problems have both been minimized by implementing a gridless MCP detector and a new Si design making the measurement feasible. Supported by the US DOE under Grant No. DEFG02-88ER-40404
From nucleons to nuclei to fusion reactions
NASA Astrophysics Data System (ADS)
Quaglioni, S.; Navrátil, P.; Roth, R.; Horiuchi, W.
2012-12-01
Nuclei are prototypes of many-body open quantum systems. Complex aggregates of protons and neutrons that interact through forces arising from quantum chromo-dynamics, nuclei exhibit both bound and unbound states, which can be strongly coupled. In this respect, one of the major challenges for computational nuclear physics, is to provide a unified description of structural and reaction properties of nuclei that is based on the fundamental underlying physics: the constituent nucleons and the realistic interactions among them. This requires a combination of innovative theoretical approaches and high-performance computing. In this contribution, we present one of such promising techniques, the ab initio no-core shell model/resonating-group method, and discuss applications to light nuclei scattering and fusion reactions that power stars and Earth-base fusion facilities.
From Nucleons To Nuclei To Fusion Reactions
Quaglioni, S; Navratil, P; Roth, R; Horiuchi, W
2012-02-15
Nuclei are prototypes of many-body open quantum systems. Complex aggregates of protons and neutrons that interact through forces arising from quantum chromo-dynamics, nuclei exhibit both bound and unbound states, which can be strongly coupled. In this respect, one of the major challenges for computational nuclear physics, is to provide a unified description of structural and reaction properties of nuclei that is based on the fundamental underlying physics: the constituent nucleons and the realistic interactions among them. This requires a combination of innovative theoretical approaches and high-performance computing. In this contribution, we present one of such promising techniques, the ab initio no-core shell model/resonating-group method, and discuss applications to light nuclei scattering and fusion reactions that power stars and Earth-base fusion facilities.
Pair counting, pion-exchange forces and the structure of light nuclei
Wiringa, R.B.
2006-03-15
A simple but useful guide for understanding the structure of light nuclei is presented. It is based on counting the number of interacting pairs in different spin-isospin (S,T) states for a given spatial symmetry and estimating the overall binding according to the sum of {sigma}{sub i}{center_dot}{sigma}{sub j}{tau}{sub i}{center_dot}{tau}{sub j} expectation values, as suggested by one-pion exchange. Applied to s- and p-shell nuclei, this simple picture accounts for the relative stability of nuclei as A increases and as T changes across isobars, the saturation of nuclear binding in the p shell, and the tendency to form d,t, or {alpha} subclusters there. With allowance for pairwise tensor and spin-orbit forces, which are also generated or boosted by pion exchange, the model explains why mixing of different spatial symmetries in ground states increases as T increases across isobars and why, for states of the same spatial symmetry, the ones with greater S are lower in the spectrum. The ordering of some sd-shell intruder levels can also be understood. The success of this simple model supports the idea that one-pion exchange is the dominant force controlling the structure of light nuclei.
The Structure of Light Nuclei and Its Effect on Precise Atomic Measurements
NASA Astrophysics Data System (ADS)
Friar, James L.
This review consists of three parts: (a) what every atomic physicist needs to know about the physics of light nuclei; (b) what nuclear physicists can do for atomic physics; (c) what atomic physicists can do for nuclear physics. A brief qualitative overview of the nuclear force and calculational techniques for light nuclei will be presented, with an emphasis on debunking myths and on recent progress in the field. Nuclear quantities that affect precise atomic measurements will be discussed, together with their current theoretical and experimental status. The final topic will be a discussion of those atomic measurements that would be useful to nuclear physics, and nuclear calculations that would improve our understanding of existing atomic data.
Toroidal high-spin isomers in light nuclei with N ≠ Z
NASA Astrophysics Data System (ADS)
Staszczak, A.; Wong, Cheuk-Yin
2015-11-01
The combined considerations of both the bulk liquid-drop-type behavior and the quantized aligned rotation with cranked Skyrme-Hartree-Fock approach revealed previously (Staszczak and Wong 2014 Phys. Lett. B 738 401) that even-even, N = Z, toroidal high-spin isomeric states have general occurrences for light nuclei with 28≤slant A≤slant 52. We find that in this mass region there are in addition N\
Ab initio no core calculations of light nuclei and preludes to Hamiltonian quantum field theory
Vary, J. P.; Maris, P.; Honkanen, H.; Li, J.; Shirokov, A. M.; Brodsky, S. J.; Harindranath, A.
2009-12-17
Recent advances in ab initio quantum many-body methods and growth in computer power now enable highly precise calculations of nuclear structure. The precision has attained a level sufficient to make clear statements on the nature of 3-body forces in nuclear physics. Total binding energies, spin-dependent structure effects, and electroweak properties of light nuclei play major roles in pinpointing properties of the underlying strong interaction. Eventually, we anticipate a theory bridge with immense predictive power from QCD through nuclear forces to nuclear structure and nuclear reactions. Light front Hamiltonian quantum field theory offers an attractive pathway and we outline key elements.
Ab initio no core calculations of light nuclei and preludes to Hamiltonian quantum field theory
Vary, J.P.; Maris, P.; Shirokov, A.M.; Honkanen, H.; li, J.; Brodsky, S.J.; Harindranath, A.; Teramond, G.F.de; /Costa Rica U.
2009-08-03
Recent advances in ab initio quantum many-body methods and growth in computer power now enable highly precise calculations of nuclear structure. The precision has attained a level sufficient to make clear statements on the nature of 3-body forces in nuclear physics. Total binding energies, spin-dependent structure effects, and electroweak properties of light nuclei play major roles in pinpointing properties of the underlying strong interaction. Eventually,we anticipate a theory bridge with immense predictive power from QCD through nuclear forces to nuclear structure and nuclear reactions. Light front Hamiltonian quantum field theory offers an attractive pathway and we outline key elements.
The influence of s states near threshold on the structure of light nuclei
NASA Astrophysics Data System (ADS)
Hoffman, Calem
2015-10-01
A recent work identified the role of neutron s states, and their proximity to the neutron separation threshold, on the ordering of the 1s1 / 2 and 0d5 / 2 single-particle levels in light nuclei. A simple Woods-Saxon potential was used to reproduce the systematic data available for these two levels with great success by accounting for the s state binding energy. This talk will explore other noticeable trends in light nuclei involving neutron s states and utilizing simple potential models determine the role binding energy plays. The trends and calculations will aim to provide descriptions of data and predictions of yet to be found two-particle two-hole excited states in N = 8 and 10 nuclei ranging from Z = 4-9, as well as the energies of mirror states in neutron deficient Al and Na isotopes. Results will be compared with state-of-the-art calculations. Possible future measurements capable of probing these predictions will be discussed as well. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, under Contract Number DE-AC02-06CH11357.
Thermonuclear breakup reactions of light nuclei. I - Processes and effects. [in astrophysic plasmas
NASA Technical Reports Server (NTRS)
Guessoum, Nidhal; Gould, Robert J.
1989-01-01
Temperature and density conditions are considered for the occurrence of breakup reactions of light nuclei in astrophysical plasmas. The proton-induced endothermic process is shown to be the principal mechanism for nuclear breakdown in a plasma. The phenomenon occurs at a temperature of about 1 MeV, which is a fraction of the typical binding energy per nucleon in nuclei. The temperature for breakup of He-4 is about twice as large, because of the higher binding energy. Depending on the temperature attained in the plasma, the initial concentration of elements heavier than hydrogen can be depleted. However, if it attains a temperature of about 1 MeV, breaking up the metals (C, N, O, Ne, Mg) but not He-4, an increase in the He-4 abundance by as much as 10 percent can result, since these elements essentially break down to alpha particles.
RNA metabolism in isolated nuclei: processing and transport of immunoglobulin light chain sequences.
Otegui, C; Patterson, R J
1981-01-01
Transport of prelabeled RNA from isolated myeloma nuclei is studied using conditions that permit RNA synthesis. Cytosol and spermidine are not required to maintain nuclear stability and inhibited RNA release. Omission of ATP or GTP decreased release 25 to 40%. The stimulatory effect of ATP or GTP is not due to hydrolysis of the triphosphates by the nuclear envelope NTPase, since addition of quercetin (an inhibitor of this NTPase) has no effect on the quantity of RNA released. The size distribution and percentage of poly A-containing species released from nuclei incubated with or without ATP or the other rNTPs are identical. Hybridization analysis of nuclear RNA before the transport assay revealed mature and precursor k light chain mRNA sequences. Following the transport assay, a significant fraction of k mRNA precursors is chased into mature k mRNA which is found both in nuclear-retained and released RNA. PMID:6795596
NASA Astrophysics Data System (ADS)
Galanina, L. I.; Zelenskaya, N. S.
2012-03-01
The procedure for evaluating the second-order corrections to the matrix elements of the reaction A( x, y) B, which are obtained using the method of distorted waves with a finite radius of intercluster interaction (DWBAFR), is developed. It is based on the assumption of a virtual cluster structure of light nuclei and uses integral equations for a four-body problem in the Alt-Grassberger-Sandhas formalism. These corrections are related with the mechanisms of sequential particles transfer. The latter are represented by the quadrangle diagrams. Their matrix elements are summed up coherently with those given by the pole and triangle diagrams which were calculated by using DWBAFR. The computer code QUADRO is written for the numerical implementation of the method proposed. The statistical tensors of nucleus B formed in the reaction A( x, y) B at incident particle energies of about 10 MeV/nucleon in the center of mass frame are determined. Specific calculations allowed for description of both the experimental cross sections (0-rank statistical tensors) of various reactions (including those where nucleus B has some excess neutrons) and polarized characteristics of nucleus B* (in the case of the latter produced in the exited state). A two-neutron periphery of nuclei 6He, 10Be, 12B (both in dineutron and cigarlike configurations) is restored by analyzing the differential cross sections of elastic alpha-6He-scattering and 9Be( d, p)10Be and 10B( t, p)12B reactions. It is shown that the structure of neutron peripheries is fundamentally different for these nuclei and its feature depends on the way those neutron-excess nuclei are formed: in 6He both configurations contribute to a two-neutron halo, while in 10Be there is a barely noticeable one-neutron halo, and in 12B there is a "dineutron skin". Orientation characteristics of nuclei B* are calculated. Their comparison with experimental data made it possible to draw important conclusions about a contribution to the statistical
Evidence for survival of the α cluster structure in light nuclei through the fusion process
NASA Astrophysics Data System (ADS)
Vadas, J.; Steinbach, T. K.; Schmidt, J.; Singh, Varinderjit; Haycraft, C.; Hudan, S.; deSouza, R. T.; Baby, L. T.; Kuvin, S. A.; Wiedenhöver, I.
2015-12-01
Background: Despite the importance of light-ion fusion in nucleosynthesis, a limited amount of data exist regarding the de-excitation following fusion for such systems. Purpose: To explore the characteristics of α emission associated with the decay of light fused systems at low excitation energy. Method: α particles were detected in coincidence with evaporation residues (ER) formed by the fusion of 18O and 12C nuclei. Both α particles and ERs were identified on the basis of their energy and time-of-flight. ERs were characterized by their energy spectra and angular distributions while the α particles were characterized by their energy spectra, angular distributions, and cross sections. Results: While the energy spectra and angular distributions for the α particles are relatively well reproduced by the statistical model codes, evapor and pace4 the measured cross section is substantially underpredicted by the models. Examination of the relative α emission probability for similar systems reveals that this underprediction is a more general feature of such light-ion reactions. Conclusion: Comparison of the measured relative α cross section at low Ec .m . for 18O+12C ,16O+12C , and 16O+13C indicates that the α cluster structure of the initial projectile and target nuclei influences the α emission following fusion. The underprediction of the relative α emission by the statistical model codes emphasizes that the failure of these models to account for α cluster structure is significant.
A new measurement of the flux of the light cosmic-ray nuclei at high energies
NASA Technical Reports Server (NTRS)
Buckley, J.; Dwyer, J.; Mueller, D.; Swordy, S.; Tang, K. K.
1994-01-01
A new cosmic-ray detector utilizing a ring-imaging Cerenkov counter to determine the energy of light cosmic-ray nuclei was flown on high-altitude balloon from Fort Sumner, NM, in 1991 September. We describe the design and performance of this instrument and discuss the data analysis procedures. The measurement provides a new determination of the absolute flux and differential energy spectrum of the primary cosmic-ray species helium between 40 and 320 GeV/nucleon. The experiment also yields the spectra of carbon and oxygen and some information on the intensities of the secondary nuclei Li, Be, and B. A comparison between our results and previous measurements of heavier nuclei (Z greater than or equal to 4) from HEAO 3 and Spacelab 2 indicates good consistency between these measurements. The data set is compared with the results of a leaky box propagation model. We find good agreement with this model if the abundance of helium relative to oxygen at the source is taken to be 25 +/- 6 and if the source spectrum is given by a power law in energy proportional to E(exp -2.15).
A new measurement of the flux of the light cosmic-ray nuclei at high energies
NASA Technical Reports Server (NTRS)
Buckley, J.; Dwyer, J.; Mueller, D.; Swordy, S.; Tang, K. K.
1994-01-01
A new cosmic-ray detector utilizing a ring-imaging Cerenkov counter to determine the energy of light cosmic-ray nuclei was flown on high-altitude balloon from Fort Sumner, NM, in 1991 September. We describe the design and performance of this instrument and discuss the data analysis procedures. The measurement provides a new determination of the absolute flux and differential energy spectrum of the primary cosmic-ray species helium between 40 and 320 GeV/nucleon. The experiment also yields the spectra of carbon and oxygen and some information on the intensities of the secondary nuclei Li, Be, and B. A comparison between our results and previous measurements of heavier nuclei (Z greater than or equal to 4) from HEAO 3 and Spacelab 2 indicates good consistency between these measurements. The data set is compared with the results of a leaky box propagation model. We find good agreement with this model if the abundance of helium relative to oxygen at the source is taken to be 25 +/- 6 and if the source spectrum is given by a power law in energy proportional to E(exp -2.15).
Light and circadian rhythmicity regulate MAP kinase activation in the suprachiasmatic nuclei.
Obrietan, K; Impey, S; Storm, D R
1998-12-01
Although the circadian time-keeping properties of the suprachiasmatic nuclei (SCN) require gene expression, little is known about the signal transduction pathways that initiate transcription. Here we report that a brief exposure to light during the subjective night, but not during the subjective day, activates the p44/42 mitogen-activated protein kinase (MAPK) signaling cascade in the SCN. In addition, MAPK stimulation activates CREB (cAMP response element binding protein), indicating that potential downstream transcription factors are stimulated by the MAPK pathway in the SCN. We also observed striking circadian variations in MAPK activity within the SCN, suggesting that the MAPK cascade is involved in clock rhythmicity.
Effective Field Theory and Time-Reversal Violation in Light Nuclei
NASA Astrophysics Data System (ADS)
Mereghetti, E.; van Kolck, U.
2015-10-01
Thanks to the unnaturally small value of the QCD vacuum angle [Formula: see text], time-reversal violation ([Formula: see text]) offers a window into physics beyond the Standard Model (SM) of particle physics. We review the effective field theory framework that establishes a clean connection between (a) [Formula: see text] mechanisms, which can be represented by higher-dimensional operators involving SM fields and symmetries, and (b) hadronic interactions, which allow for controlled calculations of low-energy observables involving strong interactions. The chiral properties of [Formula: see text] mechanisms lead to a pattern that should be identifiable in measurements of the electric dipole moments of the nucleon and light nuclei.
Random phase approximation for light nuclei based on fully relativistic Hartree-Fock calculations
Blunden, P.G.; McCorquodale, P.
1988-10-01
The particle-hole spectra of light nuclei are examined in the self-consistent random phase approximation based on fully relativistic Hartree and Hartree-Fock models for the nuclear ground state. The particle-hole interaction is completely prescribed by the ground-state calculation. It includes sigma, ..omega.., rho, and ..pi.. meson exchanges, with sigma and ..omega.. parameters adjusted to fit the bulk properties of nuclear matter. Differences between Hartree (no exchange) and Hartree-Fock (with exchange) predictions for the spectra are discussed.
The absorption of ultraviolet light by cell nuclei. A technique for identifying neoplastic change
Baisden, C.R.; Booker, D.; Wright, R.D. )
1989-11-01
A technique for measuring the absorption of 260-nm ultraviolet light by cell nuclei is described. The results of such measurements of normal thyroid epithelial cells and benign and malignant thyroid neoplastic cells demonstrate a progressive increase in absorbance that correlates with the histologic appearance of neoplasia. The possible theoretic basis for this phenomenon is explored. The increased nuclear absorbance observed in neoplastic cells is hypothesized to result from the disruption of hydrogen bonds between the DNA base pairs, which allows unwinding of the double helix and loss of the normal control of mitosis.
A nonemissive iridium(III) complex that specifically lights-up the nuclei of living cells.
Li, Chunyan; Yu, Mengxiao; Sun, Yun; Wu, Yongquan; Huang, Chunhui; Li, Fuyou
2011-07-27
A nonemissive cyclometalated iridium(III) solvent complex, without conjugation with a cell-penetrating molecular transporter, [Ir(ppy)(2)(DMSO)(2)](+)PF(6)(-) (LIr1), has been developed as a first reaction-based fluorescence-turn-on agent for the nuclei of living cells. LIr1 can rapidly and selectively light-up the nuclei of living cells over fixed cells, giving rise to a significant luminescence enhancement (200-fold), and shows very low cytotoxicity at the imaging concentration (incubation time <10 min, LIr1 concentration 10 μM). More importantly, in contrast to the reported nuclear stains that are based on luminescence enhancement through interaction with nucleic acids, complex LIr1 as a nuclear stain has a reaction-based mode of action, which relies on its rapid reaction with histidine/histidine-containing proteins. Cellular uptake of LIr1 has been investigated in detail under different conditions, such as at various temperatures, with hypertonic treatment, and in the presence of metabolic and endocytic inhibitors. The results have indicated that LIr1 permeates the outer and nuclear membranes of living cells through an energy-dependent entry pathway within a few minutes. As determined by an inductively coupled plasma atomic emission spectroscopy (ICP-AEC), LIr1 is accumulated in the nuclei of living cells and converted into an intensely emissive adduct. Such novel reaction-based nuclear staining for visualizing exclusively the nuclei of living cells with a significant luminescence enhancement may extend the arsenal of currently available fluorescent stains for specific staining of cellular compartments.
Plano, Santiago A; Golombek, Diego A; Chiesa, Juan J
2010-03-01
The ability to synchronize to light-dark (LD) cycles is an essential property of the circadian clock, located in mammals within the hypothalamic suprachiasmatic nuclei (SCN). Single light pulses activate nitric oxide (NO) intracellular signaling, leading to circadian phase-shifts required for synchronization. In addition, extracellular NO has a role in the SCN paracrine communication of photic phase advances. In this work, the extracellular nitrergic transmission was assessed in steady-state synchronization to LD cycles of locomotor rhythms in the golden hamster (Mesocricetus auratus). Extracellular NO levels were pharmacologically decreased in vivo with the specific scavenger, 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide (PTIO). Hamsters were subjected to LD cycles different from normal 24 h (LD 14 : 10) cycles (i.e. T-cycles), with a single 30-min light pulse presented either every 23 h (T23 cycles), or every 25 h (T25 cycles), thus allowing synchronization by advances or delays, respectively. Acute PTIO intracerebroventricular microinjections, delivered 30 min previous to the light pulse, inhibited synchronization by phase advances to T23 cycles, but did not alter phase delays under T25 cycles. In addition, NO scavenging inhibited light-induced expression of PERIOD1 protein at circadian time 18 (i.e. the time for light-induced phase advances). These findings demonstrate the role of extracellular NO communication within the SCN in the steady-state synchronization to LD cycles.
RELATIVE COMPOSITION AND ENERGY SPECTRA OF LIGHT NUCLEI IN COSMIC RAYS: RESULTS FROM AMS-01
Aguilar, M.; Alcaraz, J.; Berdugo, J.; Allaby, J.; Alpat, B.; Ambrosi, G.; Azzarello, P.; Battiston, R.; Anderhub, H.; Ao, L.; Arefiev, A.; Arruda, L.; Barao, F.; Barreira, G.; Basile, M.; Bellagamba, L.; Bartoloni, A.; Becker, R.; Becker, U.; Bene, P.
2010-11-20
Measurement of the chemical and isotopic composition of cosmic rays is essential for the precise understanding of their propagation in the galaxy. While the model parameters are mainly determined using the B/C ratio, the study of extended sets of ratios can provide stronger constraints on the propagation models. In this paper, the relative abundances of light-nuclei lithium, beryllium, boron, and carbon are presented. The secondary-to-primary ratios Li/C, Be/C, and B/C have been measured in the kinetic energy range 0.35-45 GeV nucleon{sup -1}. The isotopic ratio {sup 7}Li/{sup 6}Li is also determined in the magnetic rigidity interval 2.5-6.3 GV. The secondary-to-secondary ratios Li/Be, Li/B, and Be/B are also reported. These measurements are based on the data collected by the Alpha Magnetic Spectrometer AMS-01 during the STS-91 space shuttle flight in 1998 June. Our experimental results are in substantial agreement with other measurements, where they exist. We describe our light-nuclei data with a diffusive-reacceleration model. A 10%-15% overproduction of Be is found in the model predictions and can be attributed to uncertainties in the production cross-section data.
Relative Composition and Energy Spectra of Light Nuclei in Cosmic Rays: Results from AMS-01
NASA Astrophysics Data System (ADS)
Aguilar, M.; Alcaraz, J.; Allaby, J.; Alpat, B.; Ambrosi, G.; Anderhub, H.; Ao, L.; Arefiev, A.; Arruda, L.; Azzarello, P.; Basile, M.; Barao, F.; Barreira, G.; Bartoloni, A.; Battiston, R.; Becker, R.; Becker, U.; Bellagamba, L.; Béné, P.; Berdugo, J.; Berges, P.; Bertucci, B.; Biland, A.; Bindi, V.; Boella, G.; Boschini, M.; Bourquin, M.; Bruni, G.; Buénerd, M.; Burger, J. D.; Burger, W. J.; Cai, X. D.; Cannarsa, P.; Capell, M.; Casadei, D.; Casaus, J.; Castellini, G.; Cernuda, I.; Chang, Y. H.; Chen, H. F.; Chen, H. S.; Chen, Z. G.; Chernoplekov, N. A.; Chiueh, T. H.; Choi, Y. Y.; Cindolo, F.; Commichau, V.; Contin, A.; Cortina-Gil, E.; Crespo, D.; Cristinziani, M.; Dai, T. S.; dela Guia, C.; Delgado, C.; Di Falco, S.; Djambazov, L.; D'Antone, I.; Dong, Z. R.; Duranti, M.; Engelberg, J.; Eppling, F. J.; Eronen, T.; Extermann, P.; Favier, J.; Fiandrini, E.; Fisher, P. H.; Flügge, G.; Fouque, N.; Galaktionov, Y.; Gervasi, M.; Giovacchini, F.; Giusti, P.; Grandi, D.; Grimm, O.; Gu, W. Q.; Haino, S.; Hangarter, K.; Hasan, A.; Hermel, V.; Hofer, H.; Hungerford, W.; Ionica, M.; Jongmanns, M.; Karlamaa, K.; Karpinski, W.; Kenney, G.; Kim, D. H.; Kim, G. N.; Kim, K. S.; Kirn, T.; Klimentov, A.; Kossakowski, R.; Kounine, A.; Koutsenko, V.; Kraeber, M.; Laborie, G.; Laitinen, T.; Lamanna, G.; Laurenti, G.; Lebedev, A.; Lechanoine-Leluc, C.; Lee, M. W.; Lee, S. C.; Levi, G.; Lin, C. H.; Liu, H. T.; Lu, G.; Lu, Y. S.; Lübelsmeyer, K.; Luckey, D.; Lustermann, W.; Maña, C.; Margotti, A.; Mayet, F.; McNeil, R. R.; Menichelli, M.; Mihul, A.; Mujunen, A.; Oliva, A.; Palmonari, F.; Park, H. B.; Park, W. H.; Pauluzzi, M.; Pauss, F.; Pereira, R.; Perrin, E.; Pevsner, A.; Pilo, F.; Pimenta, M.; Plyaskin, V.; Pojidaev, V.; Pohl, M.; Produit, N.; Quadrani, L.; Rancoita, P. G.; Rapin, D.; Ren, D.; Ren, Z.; Ribordy, M.; Richeux, J. P.; Riihonen, E.; Ritakari, J.; Ro, S.; Roeser, U.; Sagdeev, R.; Santos, D.; Sartorelli, G.; Sbarra, C.; Schael, S.; Schultz von Dratzig, A.; Schwering, G.; Seo, E. S.; Shin, J. W.; Shoumilov, E.; Shoutko, V.; Siedenburg, T.; Siedling, R.; Son, D.; Song, T.; Spada, F. R.; Spinella, F.; Steuer, M.; Sun, G. S.; Suter, H.; Tang, X. W.; Ting, Samuel C. C.; Ting, S. M.; Tomassetti, N.; Tornikoski, M.; Torsti, J.; Trümper, J.; Ulbricht, J.; Urpo, S.; Valtonen, E.; Vandenhirtz, J.; Velikhov, E.; Verlaat, B.; Vetlitsky, I.; Vezzu, F.; Vialle, J. P.; Viertel, G.; Vité, D.; Von Gunten, H.; Waldmeier Wicki, S.; Wallraff, W.; Wang, J. Z.; Wiik, K.; Williams, C.; Wu, S. X.; Xia, P. C.; Xu, S.; Xu, Z. Z.; Yan, J. L.; Yan, L. G.; Yang, C. G.; Yang, J.; Yang, M.; Ye, S. W.; Zhang, H. Y.; Zhang, Z. P.; Zhao, D. X.; Zhou, F.; Zhou, Y.; Zhu, G. Y.; Zhu, W. Z.; Zhuang, H. L.; Zichichi, A.; Zimmermann, B.; Zuccon, P.
2010-11-01
Measurement of the chemical and isotopic composition of cosmic rays is essential for the precise understanding of their propagation in the galaxy. While the model parameters are mainly determined using the B/C ratio, the study of extended sets of ratios can provide stronger constraints on the propagation models. In this paper, the relative abundances of light-nuclei lithium, beryllium, boron, and carbon are presented. The secondary-to-primary ratios Li/C, Be/C, and B/C have been measured in the kinetic energy range 0.35-45 GeV nucleon-1. The isotopic ratio 7Li/6Li is also determined in the magnetic rigidity interval 2.5-6.3 GV. The secondary-to-secondary ratios Li/Be, Li/B, and Be/B are also reported. These measurements are based on the data collected by the Alpha Magnetic Spectrometer AMS-01 during the STS-91 space shuttle flight in 1998 June. Our experimental results are in substantial agreement with other measurements, where they exist. We describe our light-nuclei data with a diffusive-reacceleration model. A 10%-15% overproduction of Be is found in the model predictions and can be attributed to uncertainties in the production cross-section data.
MCNP6 Simulation of Light and Medium Nuclei Fragmentation at Intermediate Energies
Mashnik, Stepan Georgievich; Kerby, Leslie Marie
2015-05-22
MCNP6, the latest and most advanced LANL Monte Carlo transport code, representing a merger of MCNP5 and MCNPX, is actually much more than the sum of those two computer codes; MCNP6 is available to the public via RSICC at Oak Ridge, TN, USA. In the present work, MCNP6 was validated and verified (V&V) against different experimental data on intermediate-energy fragmentation reactions, and results by several other codes, using mainly the latest modifications of the Cascade-Exciton Model (CEM) and of the Los Alamos version of the Quark-Gluon String Model (LAQGSM) event generators CEM03.03 and LAQGSM03.03. It was found that MCNP6 using CEM03.03 and LAQGSM03.03 describes well fragmentation reactions induced on light and medium target nuclei by protons and light nuclei of energies around 1 GeV/nucleon and below, and can serve as a reliable simulation tool for different applications, like cosmic-ray-induced single event upsets (SEU’s), radiation protection, and cancer therapy with proton and ion beams, to name just a few. Future improvements of the predicting capabilities of MCNP6 for such reactions are possible, and are discussed in this work.
NASA Technical Reports Server (NTRS)
Chen, Y. R.; Roux, S. J.
1986-01-01
A nucleoside triphosphatase (NTPase) present in highly purified preparations of pea nuclei was partially characterized. The activity of this enzyme was stimulated by divalent cations (Mg2+ = Mn2+ > Ca2+), but was not affected by the monovalent cations, Na+ and K+. The Mg(2+)-dependent activity was further stimulated by concentrations of Ca2+ in the low micromolar range. It could catalyze the hydrolysis of ATP, GTP, UTP, and CTP, all with a pH optimum of 7.5. The nuclear NTPase activity was not inhibited by vanadate, oligomycin, or nitrate, but was inhibited by relatively low concentrations of quercetin and the calmodulin inhibitor, compound 48/80. The NTPase was stimulated more than 50% by red light, and this effect was reversed by subsequent irradiation with far-red light. The photoreversibility of the stimulation indicated that the photoreceptor for this response was phytochrome, an important regulator of photomorphogenesis and gene expression in plants.
NASA Technical Reports Server (NTRS)
Chen, Y. R.; Roux, S. J.
1986-01-01
A nucleoside triphosphatase (NTPase) present in highly purified preparations of pea nuclei was partially characterized. The activity of this enzyme was stimulated by divalent cations (Mg2+ = Mn2+ > Ca2+), but was not affected by the monovalent cations, Na+ and K+. The Mg(2+)-dependent activity was further stimulated by concentrations of Ca2+ in the low micromolar range. It could catalyze the hydrolysis of ATP, GTP, UTP, and CTP, all with a pH optimum of 7.5. The nuclear NTPase activity was not inhibited by vanadate, oligomycin, or nitrate, but was inhibited by relatively low concentrations of quercetin and the calmodulin inhibitor, compound 48/80. The NTPase was stimulated more than 50% by red light, and this effect was reversed by subsequent irradiation with far-red light. The photoreversibility of the stimulation indicated that the photoreceptor for this response was phytochrome, an important regulator of photomorphogenesis and gene expression in plants.
Signatures of α clustering in light nuclei from relativistic nuclear collisions.
Broniowski, Wojciech; Ruiz Arriola, Enrique
2014-03-21
We argue that relativistic nuclear collisions may provide experimental evidence of α clustering in light nuclei. A light α-clustered nucleus has a large intrinsic deformation. When collided against a heavy nucleus at very high energies, this deformation transforms into the deformation of the fireball in the transverse plane. The subsequent collective evolution of the fireball leads to harmonic flow reflecting the deformation of the initial shape, which can be measured with standard methods of relativistic heavy-ion collisions. We illustrate the feasibility of the idea by modeling the (12)C-(208)Pb collisions and point out that very significant quantitative and qualitative differences between the α-clustered and uniform (12)C nucleus occur in such quantities as the triangular flow, its event-by-event fluctuations, or the correlations of the elliptic and triangular flows. The proposal offers a possibility of studying low-energy nuclear structure phenomena with "snapshots" made with relativistic heavy-ion collisions.
Furusawa, Shun; Nagakura, Hiroki; Yamada, Shoichi; Sumiyoshi, Kohsuke
2013-09-01
We perform numerical experiments to investigate the influence of inelastic neutrino reactions with light nuclei on the standing accretion shock instability (SASI). The time evolution of shock waves is calculated with a simple light-bulb approximation for the neutrino transport and a multi-nuclei equation of state. The neutrino absorptions and inelastic interactions with deuterons, tritons, helions, and alpha particles are taken into account in the hydrodynamical simulations. In addition, the effects of ordinary charged-current interactions with nucleons is addressed in the simulations. Axial symmetry is assumed but no equatorial symmetry is imposed. We show that the heating rates of deuterons reach as high as {approx}10% of those of nucleons around the bottom of the gain region. On the other hand, alpha particles are heated near the shock wave, which is important when the shock wave expands and the density and temperature of matter become low. It is also found that the models with heating by light nuclei evolve differently in the non-linear phase of SASI than do models that lack heating by light nuclei. This result is because matter in the gain region has a varying density and temperature and therefore sub-regions appear that are locally rich in deuterons and alpha particles. Although the light nuclei are never dominant heating sources and they work favorably for shock revival in some cases and unfavorably in other cases, they are non-negligible and warrant further investigation.
NASA Astrophysics Data System (ADS)
Furusawa, Shun; Nagakura, Hiroki; Sumiyoshi, Kohsuke; Yamada, Shoichi
2013-09-01
We perform numerical experiments to investigate the influence of inelastic neutrino reactions with light nuclei on the standing accretion shock instability (SASI). The time evolution of shock waves is calculated with a simple light-bulb approximation for the neutrino transport and a multi-nuclei equation of state. The neutrino absorptions and inelastic interactions with deuterons, tritons, helions, and alpha particles are taken into account in the hydrodynamical simulations. In addition, the effects of ordinary charged-current interactions with nucleons is addressed in the simulations. Axial symmetry is assumed but no equatorial symmetry is imposed. We show that the heating rates of deuterons reach as high as ~10% of those of nucleons around the bottom of the gain region. On the other hand, alpha particles are heated near the shock wave, which is important when the shock wave expands and the density and temperature of matter become low. It is also found that the models with heating by light nuclei evolve differently in the non-linear phase of SASI than do models that lack heating by light nuclei. This result is because matter in the gain region has a varying density and temperature and therefore sub-regions appear that are locally rich in deuterons and alpha particles. Although the light nuclei are never dominant heating sources and they work favorably for shock revival in some cases and unfavorably in other cases, they are non-negligible and warrant further investigation.
Lifetime Measurements of Tagged Exotic- and Unbound Nuclear States
Cullen, D. M.
2011-11-30
A new Differential Plunger device for measuring pico-second lifetimes of Unbound Nuclear States (DPUNS) is being built at The University of Manchester. DPUNS has been designed to work with alpha-, beta- and isomer-tagging methods using the existing JUROGAM II--RITU--GREAT infrastructure at the University of Jyvaskyla, Finland. The importance of proton emission from nuclei is that it provides valuable nuclear-structure information as direct input to nuclear models beyond the drip line. New experimental data beyond the drip line can provide new extensions to these models especially with the possible coupling of weakly bound and unbound states to the continuum. The results of the first experiments to measure lifetimes of unbound nuclear states with this method was discussed along with possible future experiments which can be addressed with DPUNS using proton-, isomer- and alpha-tagging.
Exotic Behavior at Ultrahigh Spin Values in Light Rare-Earth N~90 Nuclei
NASA Astrophysics Data System (ADS)
Riley, M. A.; Wang, X.; Simpson, J.; Paul, E. S.; Janssens, R. V. F.; Nolan, P. J.; Ayangeakaa, A. D.; Boston, H. C.; Carpenter, M. P.; Chiara, C. J.; Garg, U.; Hampson, P.; Hartley, D. J.; Hoffman, C. R.; Judson, D. S.; Kondev, F. G.; Lauritsen, T.; Lumley, N. M.; Matta, J.; Miller, S.; Ollier, J.; Petri, M.; Radford, D. C.; Rees, J. M.; Revill, J. P.; Riedinger, L. L.; Rigby, S. V.; Unsworth, C.; Zhu, S.; Ragnarsson, I.
2014-09-01
The light rare-earth nuclei near N = 90, e.g. 158Er, are textbook examples of the evolution of nuclear structure with excitation energy and angular momentum. They display a variety of different phenomena, such as, multiple backbends, dramatic shape changes and band termination. However, after several decades of trying, it is only in the last few years that we have been able to observe structures beyond band termination. A spectacular return to collectivity has been found to take place extending discrete gamma-ray spectroscopy into the so-called "ultrahigh-spin regime" (I = 50-70). These sequences, observed in 157,158Er, were initially interpreted as being associated with a particularly stable and energetically favored strongly deformed triaxial shape minimum. However recent quadrupole moment measurements appear to be inconsistent with this early suggestion and have generated a good deal of theoretical discussion. This surprising observation is discussed along with news on similar structures in other neighboring nuclei.
Variation after parity projection calculation with the Skyrme interaction for light nuclei
Ohta, H.; Yabana, K.; Nakatsukasa, T.
2004-07-01
A self-consistent calculation with variation after parity projection is proposed to study both ground and excited states of light nuclei. This procedure provides description of the ground state incorporating some correlation effects, and self-consistent solutions for the excited states of negative parity. For flexible description of nuclear shapes, single particle orbitals are represented on a uniform grid in the three-dimensional Cartesian coordinates. The angular momentum projection is performed after variation to calculate rotational spectra. To demonstrate the usefulness of the method, results are shown for two N=Z nuclei, {sup 20}Ne and {sup 12}C, for which clustering correlations are known to be important. In the {sup 20}Ne nucleus, both cluster-like and shell-model-like states are described simultaneously in the present framework. For {sup 12}C nucleus, the appearance of three-alpha clustering correlation in the ground state is investigated in relation to the strength of the two-body spin-orbit interaction.
Gamma ray astronomy and the origin of the light nuclei. [cosmic ray and interstellar gas reactions
NASA Technical Reports Server (NTRS)
Reeves, H.
1978-01-01
Nuclear reactions induced by the collisions of the protons and alphas of the galactic cosmic ray with heavy nuclei of the interstellar gas are responsible for the continuous production of the light elements lithium, beryllium, and boron in the galaxy. To better than one order of magnitude, the observed ratios of these abundances to hydrogen abundance and the nuclidic abundance ratios between themselves are accounted for by simply considering the effect of fast protons and alphas with a flux and an energy spectrum as observed in galactic cosmic rays, for a period comparable with the life of our galaxy. The role of gamma ray astronomy in solving problems that occur when accurate agreement is sought with increasingly accurate data is discussed.
Finite nuclei in relativistic models with a light chiral scalar meson
Furnstahl, R.J. ); Serot, B.D. )
1993-05-01
Relativistic chiral models with a light scalar meson appear to provide an economical marriage of successful relativistic mean-field theories and chiral symmetry. The scalar meson serves as both the chiral partner of the pion and the mediator of the intermediate-range nucleon-nucleon ([ital NN]) attraction. However, while some of these models can reproduce the empirical nuclear matter saturation point, they fail to reproduce observed properties of finite nuclei, such as spin-orbit splittings, shell structure, charge densities, and surface energetics. These deficiencies imply that this realization of chiral symmetry is incorrect. An alternative scenario, which features a heavy chiral scalar and dynamical generation of the [ital NN] attraction, is discussed.
Finite nuclei in relativistic models with a light chiral scalar meson
Serot, B.D.; Furnstahl, R.J.
1993-10-01
Relativistic chiral models with a light scalar, meson appear to provide an economical marriage of successful relativistic mean-field theories and chiral symmetry. In these models, the scalar meson serves as both the chiral partner of the pion and the mediator of the intermediate-range nucleon-nucleon (NN) attraction. However, while some of these models can reproduce the empirical nuclear matter saturation point, they fail to reproduce observed properties of finite nuclei, such as spin-orbit splittings, shell structure, charge densities, and surface energetics. There deficiencies imply that this realization of chiral symmetry is incorrect. An alternative scenario for chiral hadronic models, which features a heavy chiral scalar and dynamical generation of the NN attraction, is discussed.
Experimental results on multi-nucleonic K- absorptions in light nuclei
NASA Astrophysics Data System (ADS)
Vázquez Doce, O.; Cargnelli, M.; Curceanu, C.; Del Grande, R.; Fabbietti, L.; Marton, J.; Piscicchia, K.; Scordo, A.; Sirghi, D.; Tucakovic, I.; Wycech, S.; Zmeskal, J.; Anastasi, A.; Curciarello, F.; Czerwinski, E.; Krzemien, W.; Mandaglio, G.; Martini, M.; Moskal, P.; Patera, V.; Perez del Rio, E.; Silarski, M.
2017-03-01
The AMADEUS collaboration studied the K- absorptions at low momentum in light nuclei leading to Σ0p final state. Those events were recorded by the KLOE detector, used as an active target, installed in the the DAΦNE collider. The results show that it is possible to isolate the process where the K- is absorbed by two nucleons and the decay products are emitted without any further final state interactions among other contributions involving more than two nucleons. Further, the possible contribution of a ppK- bound state was investigated. The best fit gives space to a yield of ppK-/Kstop- = (0.044 ± 0.009 stat-0.005+0.004) × 10-2 corresponding to a binding energy and a width of 45 and 30 MeV/c2, respectively. A statistical analysis of this result shows although that its significance is only at the level of 1σ.
Chiral Three-Nucleon Interactions in Light Nuclei, Neutron-α Scattering, and Neutron Matter
NASA Astrophysics Data System (ADS)
Lynn, J. E.; Tews, I.; Carlson, J.; Gandolfi, S.; Gezerlis, A.; Schmidt, K. E.; Schwenk, A.
2016-02-01
We present quantum Monte Carlo calculations of light nuclei, neutron-α scattering, and neutron matter using local two- and three-nucleon (3 N ) interactions derived from chiral effective field theory up to next-to-next-to-leading order (N2LO ). The two undetermined 3 N low-energy couplings are fit to the 4He binding energy and, for the first time, to the spin-orbit splitting in the neutron-α P -wave phase shifts. Furthermore, we investigate different choices of local 3 N -operator structures and find that chiral interactions at N2LO are able to simultaneously reproduce the properties of A =3 ,4 ,5 systems and of neutron matter, in contrast to commonly used phenomenological 3 N interactions.
Chiral Three-Nucleon Interactions in Light Nuclei, Neutron-α Scattering, and Neutron Matter.
Lynn, J E; Tews, I; Carlson, J; Gandolfi, S; Gezerlis, A; Schmidt, K E; Schwenk, A
2016-02-12
We present quantum Monte Carlo calculations of light nuclei, neutron-α scattering, and neutron matter using local two- and three-nucleon (3N) interactions derived from chiral effective field theory up to next-to-next-to-leading order (N(2)LO). The two undetermined 3N low-energy couplings are fit to the (4)He binding energy and, for the first time, to the spin-orbit splitting in the neutron-α P-wave phase shifts. Furthermore, we investigate different choices of local 3N-operator structures and find that chiral interactions at N(2)LO are able to simultaneously reproduce the properties of A=3,4,5 systems and of neutron matter, in contrast to commonly used phenomenological 3N interactions.
Chiral Three-Nucleon Interactions in Light Nuclei, Neutron-α Scattering, and Neutron Matter
Lynn, J. E.; Tews, I.; Carlson, Joseph Allen; Gandolfi, Stefano; Gezerlis, A.; Schmidt, K. E.; Schwenk, A.
2016-02-09
Here we present quantum Monte Carlo calculations of light nuclei, neutron- scattering, and neutron matter using local two- and three-nucleon (3N) interactions derived from chiral e effective fi eld theory up to next-to-next-to-leading order (N^{2}LO). The two undetermined 3N low-energy couplings are fi t to the ^{4}He binding energy and, for the first time, to the spin-orbit splitting in the neutron- P-wave phase shifts. Furthermore, we investigate different choices of local 3N-operator structures and find that chiral interactions at N^{2}LO are able to simultaneously reproduce the properties of A = 3; 4; 5 systems and of neutron matter, in contrast to commonly used phenomenological 3N interactions.
Chiral Three-Nucleon Interactions in Light Nuclei, Neutron-α Scattering, and Neutron Matter
Lynn, J. E.; Tews, I.; Carlson, Joseph Allen; ...
2016-02-09
Here we present quantum Monte Carlo calculations of light nuclei, neutron- scattering, and neutron matter using local two- and three-nucleon (3N) interactions derived from chiral e effective fi eld theory up to next-to-next-to-leading order (N2LO). The two undetermined 3N low-energy couplings are fi t to the 4He binding energy and, for the first time, to the spin-orbit splitting in the neutron- P-wave phase shifts. Furthermore, we investigate different choices of local 3N-operator structures and find that chiral interactions at N2LO are able to simultaneously reproduce the properties of A = 3; 4; 5 systems and of neutron matter, in contrastmore » to commonly used phenomenological 3N interactions.« less
Clustering effects in fusion evaporation reactions with light even-even N=Z nuclei
NASA Astrophysics Data System (ADS)
Morelli, L.; D'Agostino, M.; Bruno, M.; Frosin, C.; Gulminelli, F.; Gramegna, F.; Cinausero, M.; Marchi, T.; Fabris, D.; Degerlier, M.; Casini, G.; Barlini, S.; Bini, M.; Pasquali, G.; Olmi, A.; Piantelli, S.; Valdré, S.; Pastore, G.; Gelli, N.; Vardaci, E.
2017-06-01
In the recent years, cluster structures have been evidenced in many ground and excited states of light nuclei [1, 2]. In the currently experimental campaign, the NUCL-EX collaboration has measured the12C+12C and14N+10B reactions at 95 MeV and 80 MeV respectively. The experimental data corresponding to complete fusion of target and projectile into an excited24Mg nucleus was compared to the results of a pure statistical model [3, 4]. In addition, data from12C+12C have been analyzed to investigate the decay of the Hoyle state of12C* [12] obtained as an intermediate step in the 6α decay channel of the24Mg* formed in central events.
Ab-Initio Hamiltonian Approach to Light Nuclei And to Quantum Field Theory
Vary, J.P.; Honkanen, H.; Li, Jun; Maris, P.; Shirokov, A.M.; Brodsky, S.J.; Harindranath, A.; de Teramond, G.F.; Ng, E.G.; Yang, C.; Sosonkina, M.; /Ames Lab
2012-06-22
Nuclear structure physics is on the threshold of confronting several long-standing problems such as the origin of shell structure from basic nucleon-nucleon and three-nucleon interactions. At the same time those interactions are being developed with increasing contact to QCD, the underlying theory of the strong interactions, using effective field theory. The motivation is clear - QCD offers the promise of great predictive power spanning phenomena on multiple scales from quarks and gluons to nuclear structure. However, new tools that involve non-perturbative methods are required to build bridges from one scale to the next. We present an overview of recent theoretical and computational progress with a Hamiltonian approach to build these bridges and provide illustrative results for the nuclear structure of light nuclei and quantum field theory.
Correlation Analysis of Optical and Radio Light Curves for a Large Sample of Active Galactic Nuclei
NASA Astrophysics Data System (ADS)
Clements, S. D.; Smith, A. G.; Aller, H. D.; Aller, M. F.
1995-08-01
The Rosemary Hill Observatory has accumulated internally consistent light curves extending over as much as 26 years for a large sample of active galactic nuclei. Forty-six of these optical records have been compared with similar radio records from the University of Michigan Radio Astronomy Observatory and the Algonquin Radio Observatory. For 18 objects, pairs of records were sufficiently long and unconfused to allow reliable application of the Discrete Correlation Function analysis; this group included 8 BL Lacertids, 8 quasars, and 2 Seyfert galaxies. Nine of the 18 sources showed positive radio-optical correlations, with the radio events lagging the optical by intervals ranging from 0 to 14 months. Consistent with the relativistic beaming model of the BL Lacertids, the group displaying correlations was dominated by this type of object.
PRODUCTION OF LIGHT-ELEMENT PRIMARY PROCESS NUCLEI IN NEUTRINO-DRIVEN WINDS
Arcones, A.; Montes, F.
2011-04-10
We present first comparisons between light-element primary process (LEPP) abundances observed in some ultra metal-poor (UMP) stars and nucleosynthesis calculations based on long-time hydrodynamical simulations of core-collapse supernovae and their neutrino-driven wind. UMP star observations indicate that Z {>=} 38 elements include the contributions of at least two nucleosynthesis components: r-process nuclei that are synthesized by rapid neutron capture in a yet unknown site and LEPP elements (mainly Sr, Y, and Zr). We show that neutrino-driven wind simulations can explain the observed LEPP pattern. We explore in detail the sensitivity of the calculated abundances to the electron fraction, which is a key nucleosynthesis parameter but poorly known due to uncertainties in neutrino interactions and transport. Our results show that the observed LEPP pattern can be reproduced in proton- and neutron-rich winds.
AMS results on the fluxes of light nuclei in cosmic rays
NASA Astrophysics Data System (ADS)
Bertucci, Bruna; AMS Collaboration
2017-01-01
AMS-02 is a wide acceptance high-energy physics experiment installed on the International Space Station in May 2011 and it has been operating continuously since then. AMS-02 is able to separate cosmic rays light nuclei species (1 <= Z <= 8) with contaminations less than 10-3 thanks to the redundant measurement of the particle charge in eight silicon tracker layers, four scintillator planes and the Ring Imaging Cherenkov detector. The accurate measure of their spectrum in the GeV-TeV range is performed by the magnetic spectrometer with a maximum detectable rigidity of 2-3 TV. Precise measurements from AMS will be presented, including proton, helium, boron to carbon flux ratio, and highlights of ongoing analyses discussed. On behalf of the AMS Collaboration.
Furusawa, Shun; Yamada, Shoichi; Nagakura, Hiroki; Sumiyoshi, Kohsuke; Suzuki, Hideyuki
2014-05-02
We perform numerical experiments to investigate the influence of inelastic neutrino reactions with light nuclei on the standing accretion shock instability. The time evolutions of shock waves are calculated with a simple light-bulb approximation for the neutrino transport and a multi-nuclei equation of state. The neutrino absorptions and inelastic interactions with deuterons, tritons, helions and alpha particles are taken into account in the hydrodynamical simulations in addition to the ordinary charged-current interactions with nucleons. Axial symmetry is assumed but no equatorial symmetry is imposed. We show that the heating rates of deuterons reach as high as ∼ 10% of those of nucleons around the bottom of the gain region. On the other hands, alpha particles heat the matter near the shock wave, which is important when the shock wave expands and density and temperature of matter become low. It is also found that the models with heating by light nuclei have different evolutions from those without it in non-linear evolution phase. The matter in the gain region has various densities and temperatures and there appear regions that are locally rich in deuterons and alpha particles. These results indicate that the inelastic reactions of light nuclei, especially deuterons, should be incorporated in the simulations of core-collapse supernovae.
NASA Astrophysics Data System (ADS)
Furusawa, Shun; Nagakura, Hiroki; Sumiyoshi, Kohsuke; Yamada, Shoichi; Suzuki, Hideyuki
2014-05-01
We perform numerical experiments to investigate the influence of inelastic neutrino reactions with light nuclei on the standing accretion shock instability. The time evolutions of shock waves are calculated with a simple light-bulb approximation for the neutrino transport and a multi-nuclei equation of state. The neutrino absorptions and inelastic interactions with deuterons, tritons, helions and alpha particles are taken into account in the hydrodynamical simulations in addition to the ordinary charged-current interactions with nucleons. Axial symmetry is assumed but no equatorial symmetry is imposed. We show that the heating rates of deuterons reach as high as ˜ 10% of those of nucleons around the bottom of the gain region. On the other hands, alpha particles heat the matter near the shock wave, which is important when the shock wave expands and density and temperature of matter become low. It is also found that the models with heating by light nuclei have different evolutions from those without it in non-linear evolution phase. The matter in the gain region has various densities and temperatures and there appear regions that are locally rich in deuterons and alpha particles. These results indicate that the inelastic reactions of light nuclei, especially deuterons, should be incorporated in the simulations of core-collapse supernovae.
Calculation of primordial abundances of light nuclei including a heavy sterile neutrino
Mosquera, M.E.; Civitarese, O. E-mail: osvaldo.civitarese@fisica.unlp.edu.ar
2015-08-01
We include the coupling of a heavy sterile neutrino with active neutrinos in the calculation of primordial abundances of light-nuclei. We calculate neutrino distribution functions and primordial abundances, as functions depending on a renormalization of the sterile neutrino distribution function (a), the sterile neutrino mass (m{sub s}) and the mixing angle (φ). Using the observable data, we set constrains on these parameters, which have the values 0a < 0.4, sin{sup 2} φ ≈ 0.12−0.39 and 0m{sub s} < 7 keV at 1σ level, for a fixed value of the baryon to photon ratio. When the baryon to photon ratio is allowed to vary, its extracted value is in agreement with the values constrained by Planck observations and by the Wilkinson Microwave Anisotropy Probe (WMAP). It is found that the anomaly in the abundance of {sup 7}Li persists, in spite of the inclusion of a heavy sterile neutrino.
Folding Model Analysis of Elastic Scattering of 11B from Light, Medium, and Heavy Nuclei
NASA Astrophysics Data System (ADS)
Aygun, M.
2016-11-01
The elastic scattering angular distributions of 11B projectile on light, medium, and heavy target nuclei including 7Li, 9Be, 12C, 16O, 24,25,26Mg, 27Al, 28Si, 40Ca, 58Ni, 59Co, 60Ni, 197Au, 208Pb, and 209Bi have been analyzed at various incident energies. The theoretical results have been obtained by using two different nuclear potentials within the framework of the optical model (OM). Firstly, the double folding potential for real part and the Wood—Saxon (WS) potential for imaginary part have been applied. Secondly, the calculations with double folding potential for both real and imaginary part have been performed and compared with the experimental data. It has been seen that the results are in very good agreement with the experimental data. Also, the volume integrals and cross-sections for each reaction have been obtained. Finally, a new and simple formula for the imaginary potential depth has been derived to clarify the nuclear interactions of 11B nucleus at low energy reactions.
Investigation of the low energy kaons hadronic interactions in light nuclei by AMADEUS
NASA Astrophysics Data System (ADS)
Piscicchia, K.; Bazzi, M.; Berucci, C.; Bosnar, D.; Bragadireanu, A. M.; Cargnelli, M.; Clozza, A.; Curceanu, C.; Grande, R. Del; D'uffizi, A.; Fabbietti, L.; Fiorini, C.; Ghio, F.; Guaraldo, C.; Iliescu, M.; Sandri, P. Levi; Marton, J.; Moskal, P.; Pietreanu, D.; Lener, M. Poli; Quaglia, R.; Romero Vidal, A.; Sbardella, E.; Scordo, A.; Shi, H.; Skurzok, M.; Silarski, M.; Sirghi, D.; Sirghi, F.; Tucakovic, I.; Doce, O. Vazquez; Widmann, E.; Zmeskal, J.
2015-08-01
The AMADEUS experiment aims to provide unique quality data for K - interaction with nucleons and light nuclei, both at-rest and in-flight (for K - momenta of about 100 MeV). The goal is to solve longstanding open issues in the non-perturbative QCD in the strangeness sector, like the nature of the Λ(1405) state, the resonant versus non-resonant yield in nuclear K - capture and the properties of kaonic nuclear clusters which are strongly related to the multi-nucleon absorption processes. We can take advantage of the DA ΦNE collider representing a unique source of monochromatic low-momentum kaons, whose nuclear interaction with the materials of the KLOE detector (used as an active target) furnish us excellent acceptance and resolution data for K - capture on H, 4He, 9Be and 12C, both at-rest and in-flight. AMADEUS step 0 consisted in the analysis of the 2004-2005 KLOE data. A second step consisted in the implementation in the central region of the KLOE detector of a pure graphite target, providing a high statistic sample of K - 12 C nuclear captures at rest. For the future, new setups for various dedicated targets are under preparation.
Fermi-LAT high-z active galactic nuclei and the extragalactic background light
NASA Astrophysics Data System (ADS)
Armstrong, Thomas; Brown, Anthony M.; Chadwick, Paula M.
2017-10-01
Observations of distant gamma-ray sources are hindered by the presence of the extragalactic background light (EBL). In order to understand the physical processes that result in the observed spectrum of sources, it is imperative that a good understanding of the EBL is included. In this work, an investigation into the imprint of the EBL on the observed spectra of high-redshift Fermi-LAT active galactic nuclei is presented. By fitting the spectrum below ˜10 GeV, an estimation of the unabsorbed intrinsic source spectrum is obtained; by applying this spectrum to data up to 300 GeV, it is then possible to derive a scaling factor for different EBL models. A second approach uses five sources (PKS 0426-380, 4C +55.17, Ton 116, PG 1246+586 and RBS 1432) that were found to exhibit very high energy (VHE) emission (Eγ > 100 GeV). Through Monte Carlo simulations, it is shown that the observation of VHE photons, despite the large distances of these objects, is consistent with current EBL models. Many of these sources would be observable with the upcoming ground-based observatory, the Cherenkov Telescope Array, leading to a better understanding of the EBL.
Thermal properties of light nuclei from 12C + 12C fusion-evaporation reactions
NASA Astrophysics Data System (ADS)
Morelli, L.; Baiocco, G.; D'Agostino, M.; Gulminelli, F.; Bruno, M.; Abbondanno, U.; Appannababu, S.; Barlini, S.; Bini, M.; Casini, G.; Cinausero, M.; Degerlier, M.; Fabris, D.; Gelli, N.; Gramegna, F.; Kravchuk, V. L.; Marchi, T.; Olmi, A.; Pasquali, G.; Piantelli, S.; Valdré, S.; Raduta, Ad R.
2014-07-01
The 12C + 12C reaction at 95 MeV has been studied through the complete charge identification of its products by means of the GARFIELD+RCo experimental set-up at INFN Laboratori Nazionali di Legnaro (LNL). In this paper, the first of a series of two, a comparison to a dedicated Hauser-Feshbach calculation allows selecting a set of dissipative events which corresponds, to a large extent, to the statistical evaporation of highly excited 24Mg. Information on the isotopic distribution of the evaporation residues in coincidence with their complete evaporation chain is also extracted. The set of data puts strong constraints on the behaviour of the level density (LD) of light nuclei above the threshold for particle emission. In particular, a fast increase of the LD parameter with excitation energy is supported by the data. Residual deviations from a statistical behaviour are seen in two specific channels, and tentatively associated with a contamination from direct reactions and/or α-clustering effects. These channels are studied in further details in the second paper of the series.
NASA Astrophysics Data System (ADS)
Sutter, Kiplangat
This thesis illustrates the utilization of Density functional theory (DFT) in calculations of gas and solution phase Nuclear Magnetic Resonance (NMR) properties of light and heavy nuclei. Computing NMR properties is still a challenge and there are many unknown factors that are still being explored. For instance, influence of hydrogen-bonding; thermal motion; vibration; rotation and solvent effects. In one of the theoretical studies of 195Pt NMR chemical shift in cisplatin and its derivatives illustrated in Chapter 2 and 3 of this thesis. The importance of representing explicit solvent molecules explicitly around the Pt center in cisplatin complexes was outlined. In the same complexes, solvent effect contributed about half of the J(Pt-N) coupling constant. Indicating the significance of considering the surrounding solvent molecules in elucidating the NMR measurements of cisplatin binding to DNA. In chapter 4, we explore the Spin-Orbit (SO) effects on the 29Si and 13C chemical shifts induced by surrounding metal and ligands. The unusual Ni, Pd, Pt trends in SO effects to the 29Si in metallasilatrane complexes X-Si-(mu-mt)4-M-Y was interpreted based on electronic and relativistic effects rather than by structural differences between the complexes. In addition, we develop a non-linear model for predicting NMR SO effects in a series of organics bonded to heavy nuclei halides. In chapter 5, we extend the idea of "Chemist's orbitals" LMO analysis to the quantum chemical proton NMR computation of systems with internal resonance-assisted hydrogen bonds. Consequently, we explicitly link the relationship between the NMR parameters related to H-bonded systems and intuitive picture of a chemical bond from quantum calculations. The analysis shows how NMR signatures characteristic of H-bond can be explained by local bonding and electron delocalization concepts. One shortcoming of some of the anti-cancer agents like cisplatin is that they are toxic and researchers are looking for
Sugiyama, Yuka; Kadota, Akeo
2011-03-01
Chloroplasts change their positions in the cell depending on the light conditions. In the dark, chloroplasts in fern prothallia locate along the anticlinal wall (dark position). However, chloroplasts become relocated to the periclinal wall (light position) when the light shines perpendicularly to the prothallia. Red light is effective in inducing this relocation in Adiantum capillus-veneris, and neochrome1 (neo1) has been identified as the red light receptor regulating this movement. Nevertheless, we found here that chloroplasts in neo1 mutants still become relocated from the dark position to the light position under red light. We tested four neo1 mutant alleles (neo1-1, neo1-2, neo1-3, and neo1-4), and all of them showed the red-light-induced chloroplast relocation. Furthermore, chloroplast light positioning under red light occurred also in Pteris vittata, another fern species naturally lacking the neo1-dependent phenomenon. The light positioning of chloroplasts occurred independently of the direction of red light, a response different to that of the neo1-dependent movement. Photosynthesis inhibitors 3-(3,4 dichlorophenyl)-1,1-dimethylurea or 2,5-dibromo-3-isopropyl-6-methyl-p-benzoquinone blocked this movement. Addition of sucrose (Suc) or glucose to the culture medium induced migration of the chloroplasts to the periclinal wall in darkness. Furthermore, Suc could override the effects of 3-(3,4 dichlorophenyl)-1,1-dimethylurea. Interestingly, the same light positioning was evident for nuclei under red light in the neo1 mutant. The nuclear light positioning was also induced in darkness with the addition of Suc or glucose. These results indicate that photosynthesis-dependent nondirectional movement contributes to the light positioning of these organelles in addition to the neo1-dependent directional movement toward light.
Womble, Phillip C.; Barzilov, Alexander; Novikov, Ivan; Howard, Joseph; Musser, Jason
2009-03-10
Neutron-induced gamma-ray reactions are extensively used in the nondestructive analysis of materials and other areas where the information about the chemical composition of a substance is crucial. The common technique to find the intensity of the gamma ray is to fit gamma-ray line shape with an analytical function, for example, a Gaussian. However, the Gaussian fitting may fail if the gamma-ray peak is Doppler-broadened since this leads to the miscalculation of the area of the peak and, therefore, to misidentification of the material. Due to momentum considerations, Doppler-broadening occurs primarily with gamma rays from neutron-induced inelastic scattering reactions with light nuclei. The recoiling nucleus of interest must have excited states whose lifetimes are much smaller than the time of flight in the material. We have examined various light nuclei bombarded by 14 MeV neutrons to predict when the peak shape of a neutron-induced gamma ray emitted from these nuclei will be Doppler-broadened. We have found that nearly all the gamma rays from neutron-induced gamma-ray reactions on light elements (A<20) are Doppler-broadened with only a few exceptions. This means that utilization of resolution curves derived from isotopic sources or thermal neutron capture reactions have little value in the analysis.
New Measurements of the EMC Effect in Light Nuclei and at Large x
Gaskell, D.
2008-10-13
The modification of structure functions in nuclei (the EMC effect) has been the focus of intense experimental and theoretical study since the original observation in 1983. The EMC effect unequivocally demonstrates that quark distributions in nuclei are not simply the incoherent sum of the nucleon quark distributions. However, progress in understanding the root cause of these modifications has been hampered by the complexity of nuclear structure, making it difficult to disentangle the ''conventional'' nuclear effects of Fermi motion and binding from true medium modifications to nucleon structure. Experiment E03--103 at Jefferson Lab made measurements of nuclear structure function ratios from few--body nuclei ({sup 3}He and {sup 4}He) to deuterium, where the nuclear structure is well known, and for a range of nuclei, A = 3 to 197, at large x, where effects from Fermi motion and binding dominate.
Interactions of heavy nuclei, Kr, Xe and Ho, in light targets
NASA Technical Reports Server (NTRS)
Kertzman, M. P.; Klarmann, J.; Newport, B. J.; Stone, E. C.; Waddington, C. J.; Binns, W. R.; Garrard, T. L.; Israel, M. H.
1985-01-01
Over the past few years, the HEAO-3 measurements of the abundance of ultra-heavy cosmic ray nuclei (Z 26) at Earth were analyzed. In order to interpret these abundances in terms of a source composition, allowances must be made for the propagation of the nuclei in the interstellar medium. Vital to any calculation of the propagation is a knowlege of the total and partial interaction cross sections for these heavy nuclei on hydrogen. Until recently, data on such reactions have been scarce. The semi-empirical formalism of Silberberg and Tsao were relied upon to predict the partial cross sections. However, now that relativistic heavy ion beams are available at the LBL Bevalac, some of the cross sections of interest can be measured at energies close to those of the cosmic ray nuclei being observed.
NASA Technical Reports Server (NTRS)
Cucinotta, Francis A.; Wilson, John W.
1996-01-01
The angular momentum independent statistical decay model is often applied using a Monte-Carlo simulation to describe the decay of prefragment nuclei in heavy ion reactions. This paper presents an analytical approach to the decay problem of nuclei with mass number less than 60, which is important for galactic cosmic ray (GCR) studies. This decay problem of nuclei with mass number less than 60 incorporates well-known levels of the lightest nuclei (A less than 11) to improve convergence and accuracy. A sensitivity study of the model level density function is used to determine the impact on mass and charge distributions in nuclear fragmentation. This angular momentum independent statistical decay model also describes the momentum and energy distribution of emitted particles (n, p, d, t, h, and a) from a prefragment nucleus.
Alkhazov, G. D.; Vorobyov, A. A.; Dobrovolsky, A. V. Inglessi, A. G.; Korolev, G. A.; Khanzadeev, A. V.
2015-05-15
In order to study the spatial structure of exotic nuclei, it was proposed at the Petersburg Nuclear Physics Institute (PNPI) to measure the differential cross section for small-angle proton elastic scattering in inverse kinematics. Several experiments in beams of 0.7-GeV/nucleon exotic nuclei were performed at the heavy-ion accelerator facility of GSI (Gesellschaft für Schwerionenforschung, Darmstadt, Germany) by using the IKAR ionization spectrometer developed at PNPI. The IKAR ionization chamber filled with hydrogen at a pressure of 10 bar served simultaneously as a target and as a recoil-proton detector, which measured the recoil-proton energy. The beam-particle scattering angle was also measured. The results obtained for the cross sections in question were analyzed on the basis of the Glauber-Sitenko theory using phenomenological nuclear-density distributions with two free parameters. Nuclear-matter distributions and root-mean-square radii were found for the nuclei under investigation. The size of the halo in the {sup 6}He, {sup 8}He, {sup 11}Li, and {sup 14}Be nuclei was determined among other things. Information about neutron distributions in nuclei was deduced by combining the data obtained here with the known values of the radii of proton distributions. A sizable neutron skin was revealed in the {sup 8}Li, {sup 9}Li, and {sup 12}Be nuclei.
Interactions of heavy nuclei, Kr, Xe and Ho, in light targets
NASA Technical Reports Server (NTRS)
Kertzman, M. P.; Klarmann, J.; Newport, B. J.; Stone, E. C.; Waddington, C. J.; Binns, W. R.; Garrard, T. L.; Israel, M. H.
1985-01-01
Over the past few years, the HEAO-3 measurements of the abundances of ultra-heavy cosmic ray nuclei (Z 26) at earth have been analyzed. In order to interpret these abundances in terms of a source composition, allowance must be made for the propagation of the nuclei in the interstellar medium. Vital to any calculation of the propagation is a knowlege of the total and partial interaction cross sections for these heavy nuclei on hydrogen. Until recently, data on such reactions have been scarce. However, now that relativistic heavy ion beams are available at the LBL Bevalac, some of the cross sections of interest can be measured at energies close to those of the cosmic ray nuclei being observed. During a recent calibration at the Bevalac of an array similar to the HEAO-C3 UH-nuclei detector, targets of raphite (C), polyethylene (CH2), and aluminum were exposed to five heavy ion beams ranging in charge (Z) from 36 to 92. Total and partial charge changing cross sections for the various beam nuclei on hydrogen can be determined from the measured cross sections on C and CH2, and will be applied to the propagation problem. The cross sections on Al can be used to correct the abundances of UH cosmic rays observed in the HEAO C-3 detector for interactions in the detector itself.
NASA Astrophysics Data System (ADS)
Alkhazov, G. D.; Vorobyov, A. A.; Dobrovolsky, A. V.; Inglessi, A. G.; Korolev, G. A.; Khanzadeev, A. V.
2015-05-01
In order to study the spatial structure of exotic nuclei, it was proposed at the Petersburg Nuclear Physics Institute (PNPI) to measure the differential cross section for small-angle proton elastic scattering in inverse kinematics. Several experiments in beams of 0.7-GeV/nucleon exotic nuclei were performed at the heavy-ion accelerator facility of GSI (Gesellschaft für Schwerionenforschung, Darmstadt, Germany) by using the IKAR ionization spectrometer developed at PNPI. The IKAR ionization chamber filled with hydrogen at a pressure of 10 bar served simultaneously as a target and as a recoil-proton detector, which measured the recoil-proton energy. The beam-particle scattering angle was also measured. The results obtained for the cross sections in question were analyzed on the basis of the Glauber-Sitenko theory using phenomenological nuclear-density distributions with two free parameters. Nuclear-matter distributions and root-mean-square radii were found for the nuclei under investigation. The size of the halo in the 6He, 8He, 11Li, and 14Be nuclei was determined among other things. Information about neutron distributions in nuclei was deduced by combining the data obtained here with the known values of the radii of proton distributions. A sizable neutron skin was revealed in the 8Li, 9Li, and 12Be nuclei.
Dominant Modes in Light Nuclei - Ab Initio View of Emergent Symmetries
NASA Astrophysics Data System (ADS)
Draayer, J. P.; Dytrych, T.; Launey, K. D.; Dreyfuss, A. C.; Langr, D.
2015-01-01
An innovative symmetry-guided concept is discussed with a focus on emergent symmetry patterns in complex nuclei. In particular, the ab initio symmetry-adapted no-core shell model (SA-NCSM), which capitalizes on exact as well as partial symmetries that underpin the structure of nuclei, provides remarkable insight into how simple symmetry patterns emerge in the many-body nuclear dynamics from first principles. This ab initio view is complemented by a fully microscopic no-core symplectic shell-model framework (NCSpM), which, in turn, informs key features of the primary physics responsible for the emergent phenomena of large deformation and alpha-cluster substructures in studies of the challenging Hoyle state in Carbon-12 and enhanced collectivity in intermediate-mass nuclei. Furthermore, by recognizing that deformed configurations often dominate the low-energy regime, the SA-NCSM provides a strategy for determining the nature of bound states of nuclei in terms of a relatively small subspace of the symmetry-reorganized complete model space, which opens new domains of nuclei for ab initio investigations, namely, the intermediate-mass region, including isotopes of Ne, Mg, and Si.
Interactions of 200 GeV gold nuclei in light elements
NASA Technical Reports Server (NTRS)
Brewster, N. R.; Fickle, R. K.; Waddington, C. J.; Binns, W. R.; Israel, M. H.; Jones, M. D.; Klarmann, J.; Garrard, T. L.; Newport, B. J.; Stone, E. C.
1983-01-01
Total charge-changing cross sections and partial cross-sections for interactions of 200 GeV Au-197 nuclei incident on carbon and polyethylene (CH2) targets have been measured during a calibration of the HEAO-3 Heavy Nuclei Experiment. From these, the total and partial cross-sections for Au-197 incident on hydrogen are inferred. The effects of using these cross-sections in one model of cosmic ray propagation are illustrated. Comparisons to predictions using semi-empirical formulas are shown.
Self-adjointness of deformed unbounded operators
Much, Albert
2015-09-15
We consider deformations of unbounded operators by using the novel construction tool of warped convolutions. By using the Kato-Rellich theorem, we show that unbounded self-adjoint deformed operators are self-adjoint if they satisfy a certain condition. This condition proves itself to be necessary for the oscillatory integral to be well-defined. Moreover, different proofs are given for self-adjointness of deformed unbounded operators in the context of quantum mechanics and quantum field theory.
Lister, C.J.; McCutchan, E.A.
2014-06-15
A new generation of ab-initio calculations, based on realistic two- and three-body forces, is having a profound impact on our view of how nuclei work. To improve the numerical methods, and the parameterization of 3-body forces, new precise data are needed. Electromagnetic transitions are very sensitive to the dynamics which drive mixing between configurations. We have made a series of precise (< 3%) measurements of electromagnetic transitions in the A=10 nuclei {sup 10}C and {sup 10}Be by using the Doppler Shift Attenuation method carefully. Many interesting features can be reproduced including the strong α clustering. New measurements on {sup 8}Be and {sup 12}Be highlight the interplay between the alpha clusters and their valence neutrons.
Losa, C.; Doessing, T.; Pastore, A.; Vigezzi, E.; Broglia, R. A.
2010-06-15
We present a calculation of the properties of vibrational states in deformed, axially-symmetric even-even nuclei, within the framework of a fully self-consistent quasiparticle random phase approximation (QRPA). The same Skyrme energy density and density-dependent pairing functionals are used to calculate the mean field and the residual interaction in the particle-hole and particle-particle channels. We have tested our software in the case of spherical nuclei against fully self-consistent calculations published in the literature, finding excellent agreement. We investigate the consequences of neglecting the spin-orbit and Coulomb residual interactions in QRPA. Furthermore we discuss the improvement obtained in the QRPA result associated with the removal of spurious modes. Isoscalar and isovector responses in the deformed {sup 24-26}Mg, {sup 34}Mg isotopes are presented and compared to experimental findings.
Stark, Julian; Rothe, Thomas; Kieß, Steffen; Simon, Sven; Kienle, Alwin
2016-04-07
Single cell nuclei were investigated using two-dimensional angularly and spectrally resolved scattering microscopy. We show that even for a qualitative comparison of experimental and theoretical data, the standard Mie model of a homogeneous sphere proves to be insufficient. Hence, an accelerated finite-difference time-domain method using a graphics processor unit and domain decomposition was implemented to analyze the experimental scattering patterns. The measured cell nuclei were modeled as single spheres with randomly distributed spherical inclusions of different size and refractive index representing the nucleoli and clumps of chromatin. Taking into account the nuclear heterogeneity of a large number of inclusions yields a qualitative agreement between experimental and theoretical spectra and illustrates the impact of the nuclear micro- and nanostructure on the scattering patterns.
NASA Astrophysics Data System (ADS)
Caprio, Mark A.; Maris, Pieter; Vary, James P.
2014-03-01
The emergence of rotational bands has recently been observed in no-core configuration interaction (NCCI) calculations for p-shell nuclei, as evidenced by rotational patterns for excitation energies, electromagnetic moments, and electromagnetic transitions. Yrast and low-lying excited bands are found. The results demonstrate the possibility of well-developed rotational structure in NCCI calculations, using realistic nucleon-nucleon interactions, and within finite, computationally-accessible configuration spaces. This talk will focus on results for rotation in both the even-mass and odd-mass Be isotopes (7 <= A <= 12). Supported by US DOE (DE-FG02-95ER-40934, DESC0008485 SciDAC/NUCLEI, DE-FG02-87ER40371), US NSF (0904782), and Research Corporation for Science Advancement (Cottrell Scholar Award). Computational resources provided by NERSC (US DOE DE-AC02-05CH11231).
NASA Astrophysics Data System (ADS)
Stark, Julian; Rothe, Thomas; Kieß, Steffen; Simon, Sven; Kienle, Alwin
2016-04-01
Single cell nuclei were investigated using two-dimensional angularly and spectrally resolved scattering microscopy. We show that even for a qualitative comparison of experimental and theoretical data, the standard Mie model of a homogeneous sphere proves to be insufficient. Hence, an accelerated finite-difference time-domain method using a graphics processor unit and domain decomposition was implemented to analyze the experimental scattering patterns. The measured cell nuclei were modeled as single spheres with randomly distributed spherical inclusions of different size and refractive index representing the nucleoli and clumps of chromatin. Taking into account the nuclear heterogeneity of a large number of inclusions yields a qualitative agreement between experimental and theoretical spectra and illustrates the impact of the nuclear micro- and nanostructure on the scattering patterns.
Exploring Light Neutron Rich Nuclei via the ({sup 7}Li,{sup 7}Be) Reaction
Cavallaro, M.; Cappuzzello, F.; Cunsolo, A.; Foti, A.; Orrigo, S. E. A.; Rodrigues, M. R. D.; Borello-Lewin, T.; Lenske, H.; Petrascu, H.; Winfield, J. S.
2008-11-11
A systematic study of the nuclei that can be described as an integer number of {alpha} particles plus three neutrons via the ({sup 7}Li,{sup 7}Be) reaction at about 8 MeV/u has shown the presence of Bound States Embedded in the Continuum in the energy spectra. These are experimental signatures of the dynamical correlations of an easily polarizable core with a single-particle state of the valence neutron.
No-core shell-model calculations in light nuclei with three-nucleon forces
NASA Astrophysics Data System (ADS)
Barrett, B. R.; Navrátil, P.; Nogga, A.; Ormand, W. E.; Vary, J. P.
2004-12-01
The ab initio No-Core Shell Model (NCSM) has recently been expanded to include nucleon-nucleon (NN) and three-nucleon (3N) interactions at the three-body cluster level. Here it is used to predict binding energies and spectra of p-shell nuclei based on realistic NN and 3N interactions. First results show that NN plus 3N interactions based on chiral perturbation theory lead to a realistic description of 6Li.
Particle decay of proton-unbound levels in N12
Chipps, K. A.; Pain, S. D.; Greife, U.; ...
2017-04-24
Transfer reactions are a useful tool for studying nuclear structure, particularly in the regime of low level densities and strong single-particle strengths. Additionally, transfer reactions can populate levels above particle decay thresholds, allowing for the possibility of studying the subsequent decays and furthering our understanding of the nuclei being probed. In particular, the decay of loosely bound nuclei such as 12 N can help inform and improve structure models.The purpose of this paper is to learn about the decay of excited states in 12 N , to more generally inform nuclear structure models, particularly in the case of particle-unbound levelsmore » in low-mass systems which are within the reach of state-of-the-art ab initio calculations.« less
No-Core Shell Model Calculations in Light Nuclei with Three-Nucleon Forces
Barrett, B R; Vary, J P; Nogga, A; Navratil, P; Ormand, W E
2004-01-08
The ab initio No-Core Shell Model (NCSM) has recently been expanded to include nucleon-nucleon (NN) and three-nucleon (3N) interactions at the three-body cluster level. Here it is used to predict binding energies and spectra of p-shell nuclei based on realistic NN and 3N interactions. It is shown that 3N force (3NF) properties can be studied in these nuclear systems. First results show that interactions based on chiral perturbation theory lead to a realistic description of {sup 6}Li.
Three-Body Potentials in {\\varvec{α }}-Particle Model of Light Nuclei
NASA Astrophysics Data System (ADS)
Ishikawa, Souichi
2017-03-01
In three-body model calculations of atomic nuclei, e.g., the {}^{12}C nucleus as α -α -α system and the {}9Be nucleus as α -α - n system, the Hamiltonians of the systems consisting of two- and three-body potentials are important inputs. However, our knowledge of three-body potentials is quite restricted. In this paper, I will examine a relation between α -α -α and α -α - n three-body potentials that is obtained in a simple cluster model picture, which gives a phenomenological constraint condition on the three-body potential models to be used.
ERIC Educational Resources Information Center
Ebersbach, Mirjam; Luwel, Koen; Verschaffel, Lieven
2015-01-01
Children's estimation skills on a bounded and unbounded number line task were assessed in the light of their familiarity with numbers. Kindergartners, first graders, and second graders (N = 120) estimated the position of numbers on a 1--100 number line, marked with either two reference points (i.e., 1 and 10: unbounded condition) or three…
ERIC Educational Resources Information Center
Ebersbach, Mirjam; Luwel, Koen; Verschaffel, Lieven
2015-01-01
Children's estimation skills on a bounded and unbounded number line task were assessed in the light of their familiarity with numbers. Kindergartners, first graders, and second graders (N = 120) estimated the position of numbers on a 1--100 number line, marked with either two reference points (i.e., 1 and 10: unbounded condition) or three…
Particle-Gamma Studies of Transitional Gd Nuclei Via Light-Ion Reactions
NASA Astrophysics Data System (ADS)
Hughes, R. O.; Ross, T. J.; Beausang, C. W.; Allmond, J. M.; Burke, J. T.; Phair, L.; Angell, C. T.; Basunia, M. S.; Bleuel, D. L.; Casperson, R. J.; Fallon, P.; Hatarik, R.; Munson, J.; Paschalis, S.; Petri, M.; Ressler, J. J.; Scielzo, N. D.
2010-11-01
Gd nuclei with N ˜ 90 are of great interest due to a rapid change from vibrational to rotational character. Numerous experiments that have studied these nuclei were limited to either pure γ-ray or pure charged-particle studies. Recently, a series of experiments have been carried out at the 88-Inch cyclotron at LBNL, which combine relatively high-efficiency γ-ray and charged-particle spectroscopy in the same experiment. A beam of 25 MeV protons was incident on enriched ^154Gd, ^155Gd, ^156Gd and ^158Gd targets. Charged particles from the (p,p'), (p,d), and (p,t) reaction channels were detected using a Si-telescope array (STARS) and the coincident gamma-rays (in ^152-158Gd) were detected using the Liberace HPGe clover array. The relatively high particle-gamma efficiency, precise energy resolution (via the γ rays), and particle-γ angular information provides a precision tool for spectroscopic studies. Preliminary results will be presented. This work was supported in part by the DOE under grant Nos. DE-FG02-05 ER41379 & DE-FG52-06 NA26206 (UR), DE-AC52 07NA27344 (LLNL), DE-AC02 05CH11231 (LBNL).
Itoh, S; Yamakawa, T; Onishi, S; Isobe, K; Manabe, M; Sasaki, K
1986-01-01
Unbound bilirubin is oxidized to nearly colourless substances in the presence of H2O2 or ethyl hydroperoxide and horseradish peroxidase. To predict the risk of kernicterus (degenerated yellow pigmentation of nerve cells), this principle has been widely utilized for estimating the concentration of unbound bilirubin in hyperbilirubinaemic serum. However, the serum contains polar geometric photoisomers of bilirubin. Therefore, to clarify the effect of bilirubin photoisomer concentrations on unbound-bilirubin concentration, the concentration of bilirubin and its photoisomer and of unbound bilirubin in samples obtained from experiments in vivo and in vitro were simultaneously and individually estimated by h.p.l.c. and the peroxidase method. During photoirradiation, both in vivo and in vitro, the serum polar (ZE)-bilirubin IX alpha concentration increased remarkably, but unbound-bilirubin values were not affected at all. However, during experiments in vitro, unbound bilirubin concentrations increased only when concentrations of the rather polar (EZ)- and (EE)-cyclobilirubin IX alpha increased considerably in a human serum albumin-bilirubin solution irradiated with blue light. Thus it is concluded that unbound-bilirubin concentrations, and consequently the initial rate of the peroxidase reaction, is not accelerated by the increase in either (ZE)-bilirubin or (EZ)-cyclobilirubin concentration within the clinically observed range. PMID:3545181
Investigation of the low-energy kaons hadronic interactions in light nuclei by AMADEUS
NASA Astrophysics Data System (ADS)
Scordo, A.; Cargnelli, M.; Curceanu, C.; Fabbietti, L.; Marton, J.; Piscicchia, K.; Sirghi, D.; Tucakovic, I.; Vazquez Doce, O.; Wycech, S.; Zmeskal, J.; Mandaglio, G.; Martini, M.; Moskal, P.
2016-11-01
The AMADEUS experiment deals with the investigation of the low-energy kaon-nuclei hadronic interaction at the DAΦNE collider at LNF-INFN. This study is fundamental to solve longstanding questions concerning interactions of strange quarks in the non-perturbative QCD. AMADEUS step 0 consisted in the reanalysis of the 2004/2005 KLOE data, exploiting K- absorptions in H, 4He, 9Be and 12C, leading to the first invariant mass spectroscopy study with very low momentum (100 MeV/c) in-flight K- captures. In this paper, we present an overview of the analysis strategy, with particular emphasis on the results obtained in the analyses of the events with correlated Σ0 and p.
NASA Astrophysics Data System (ADS)
Lensky, Vadim; Birse, Michael C.; Walet, Niels R.
2016-09-01
We construct a coordinate-space potential based on pionless effective field theory (EFT) with a Gaussian regulator. Charge-symmetry breaking is included through the Coulomb potential and through two- and three-body contact interactions. Starting with the effective field theory potential, we apply the stochastic variational method to determine the ground states of nuclei with mass number A ≤4 . At next-to-next-to-leading order, two out of three independent three-body parameters can be fitted to the three-body binding energies. To fix the remaining one, we look for a simultaneous description of the binding energy of 4He and the charge radii of 3He and 4He. We show that at the order considered we can find an acceptable solution, within the uncertainty of the expansion. We find that the EFT expansion shows good agreement with empirical data within the estimated uncertainty, even for a system as dense as 4He.
Three-body model of light nuclei with microscopic nonlocal interactions
Theeten, M.; Baye, D.; Matsumura, H.; Orabi, M.; Descouvemont, P.; Fujiwara, Y.; Suzuki, Y.
2007-11-15
A three-body cluster model involving microscopic nonlocal interactions is developed and compared with a fully microscopic cluster model. The energy-independent nonlocal interactions are obtained from a renormalization of the energy-dependent kernels of the resonating-group method. Such interactions are derived for the {alpha}{alpha} and {alpha}n systems. The role and importance of nonlocality are discussed. These interactions are employed in three-body studies of the {alpha}nn,{alpha}{alpha}n, and 3{alpha} descriptions of the {sup 6}He, {sup 9}Be, and {sup 12}C nuclei. A comparison with fully microscopic calculations provides a measure of the importance of three-cluster exchanges in those states. The differences between both cluster-model calculations are in general small, except in the densities at short distances.
A statistical model for simulating the emission of light particles from excited nuclei
NASA Astrophysics Data System (ADS)
Sannikov, A. V.; Savitskaya, E. N.
2016-05-01
The algorithms and basic equations of a novel evaporation model that have been implemented in the program package EVAP15 are detailed. The level density of an excited nucleus is described by the composite Gilbert-Cameron formula with parameter values as suggested by the IAEA working group RIPL-3. Special attention is paid to the cross sections of inverse reactions and, in particular, to those for the interactions of low-energy neutrons with nuclei and for crossing of the Coulomb barrier by low-energy charged particles. The model predictions are compared with a large volume of experimental data on the spectra of particles emitted in the reactions ( n, xn), ( n, xp), and ( n, xα) induced by neutrons with energy near 14 MeV and on the four spectra for the reaction ( p, xp) induced by 62-MeV protons.
Kabir, Al Amin
2015-12-01
Analysis of high-energy electron scattering has been used to determine the charge radii of nuclei for several decades. Recent analysis of the Lamb shift in muonic hydrogen found an r.m.s. radius significantly different than the electron scattering result. To understand this puzzle we have analyzed the "LEDEX" data for the (e, e'p) reaction. This experiment includes measurements on several light nuclei, hydrogen, deuterium, lithium, boron, and carbon. To test our ability to measure absolute cross sections, as well as our ability to extract the charge radius, we tested our technique against the extremely well-measured carbon case and found excellent agreement using the Fourier-Bessel parametrization. We then extended the procedure to boron and lithium, which show nice agreement with the latest theoretical calculations. For hydrogen, we see clearly the limits of this technique and therefore, the charge radius is determined from the traditional extrapolation to q^{2} = 0. We will show that there is a model dependence in extracting the charge radius of hydrogen and its unambiguous determination is very difficult with available electron-scattering measurements.
Enhancement of fusion at near-barrier energies for neutron-rich light nuclei: 19O +12 C
NASA Astrophysics Data System (ADS)
Singh, Varinderjit; Vadas, J.; Steinbach, T. K.; Wiggins, B. B.; Hudan, S.; Desouza, R. T.; Baby, L. T.; Kuvin, S. A.; Tripathi, Vandana; Wiedenhover, I.; Umar, A. S.
2017-01-01
Measuring the fusion excitation function for an isotopic chain of projectile nuclei provides a sensitive test of a microscopic description of fusion. To investigate the theoretically predicted fusion enhancement for neutron-rich light nuclei, an experiment was performed to measure the fusion excitation functions for 19 O +12 C and 18 O +12 C . Using the 18O(d,p) reaction and the RESOLUT mass spectrometer at Florida State University, a beam of 19O was produced with an intensity of 2-4 x 103 p/s. This beam bombarded a 100 μg/cm2 carbon target. Using an approach optimized for the measurement of fusion with a low-intensity beam, evaporation residues (ERs) resulting from the de-excitation of the fusion product were measured. The ERs were identified by measuring their energy and time-of-flight. At near-barrier energies, an enhancement of fusion by a factor of three has been observed for 19 O +12 C in comparison to 18 O +12 C . Comparison of the experimental results with the predictions of a density constrained time-dependent Hartree-Fock (DC-TDHF) model provide evidence for the importance of pairing in the fusion process. Supported by the US DOE under Grant No. DEFG02-88ER-40404.
Unbound particles in dark matter halos
Behroozi, Peter S.; Loeb, Abraham; Wechsler, Risa H.
2013-06-13
We investigate unbound dark matter particles in halos by tracing particle trajectories in a simulation run to the far future (a = 100). We find that the traditional sum of kinetic and potential energies is a very poor predictor of which dark matter particles will eventually become unbound from halos. We also study the mass fraction of unbound particles, which increases strongly towards the edges of halos, and decreases significantly at higher redshifts. We discuss implications for dark matter detection experiments, precision calibrations of the halo mass function, the use of baryon fractions to constrain dark energy, and searches for intergalactic supernovae.
NASA Astrophysics Data System (ADS)
Seabury, E. H.; Blackburn, B. W.; Chichester, D. L.; Wharton, C. J.; Caffrey, A. J.
2007-08-01
Prompt Gamma Ray Neutron activation analysis can offer significant cost and safety advantages in the identification of explosives and toxic chemicals. As an example, the US military examined over a thousand suspect chemical munitions with Idaho National Laboratory's PINS Chemical Assay System last year. PGNAA requires, of course, a neutron source to excite the atomic nuclei of the item under test via neutron capture and inelastic neutron scattering reactions and the choice of neutron source can drastically affect PGNAA system performance. We have carried out Monte Carlo and laboratory experiments comparing DD, DT and Cf-252 neutrons incident on light and medium mass chemical elements, toward optimizing the design of future neutron-generator-based PGNAA systems for field use. We report the excitation of (n, γ) and (n, n‧) gamma rays from these elements by each type of neutron source.
Borowska, L.; Terenetsky, K.; Verbitsky, V.; Fritzsche, S.
2009-04-15
An analytical expression for the dynamic polarization potential is derived for the elastic scattering of light halo nuclei in the Coulomb field of heavy targets. The derivation is based on the adiabatic motion of the projectile below and close to the Coulomb barrier together with a uniform approximation for the Coulomb functions. Detailed computations have been carried out for the elastic scattering of d+{sup 208}Pb and {sup 6}He+{sup 208}Pb at collision energies of 8 and 17.8 MeV and are compared with measurements as far as available. The obtained expression for the dynamic polarization potential is simple and can be applied for any arbitrary system with a dineutron configuration.
NASA Astrophysics Data System (ADS)
Maj, A.; Kmiecik, M.; Brekiesz, M.; Grebosz, J.; Meczyński, W.; Styczeń, J.; Ziebliński, M.; Zuber, K.; Bracco, A.; Camera, F.; Benzoni, G.; Million, B.; Blasi, N.; Brambilla, S.; Leoni, S.; Pignanelli, M.; Wieland, O.; Airoldi, A.; Herskind, B.; Bednarczyk, P.; Curien, D.; Farnea, E.; de Angelis, G.; Napoli, D. R.; Nyberg, J.; Kicińska-Habior, M.; Petrache, C. M.; Petrache, D.; Dubray, N.; Dudek, J.; Pomorski, K.
2004-02-01
The high-energy and discrete γ-ray spectra, as well as the charged particle angular distribution have been measured in the reaction 105 MeV 18O+28Si using the EUROBALL IV, HECTOR and EUCLIDES arrays in order to investigate the predicted Jacobi shape transition in light nuclei. A comparison of the GDR line shape data with the predictions of the thermal shape fluctuation model, based on the most recent rotating liquid drop LSD calculations, shows evidence for such Jacobi shape transition in hot, rapidly rotating 46Ti. The found narrow low-energy component in the GDR line shape is interpreted as the consequence both of the elongated shape and of the Coriolis effect.
Maj, A.; Kmiecik, M.; Brekiesz, M.; Grebosz, J.; Meczynski, W.; Styczen, J.; Zieblinski, M.; Zuber, K.; Bracco, A.; Camera, F.; Benzoni, G.; Million, B.; Blasi, N.; Brambilla, S.; Leoni, S.; Pignanelli, M.; Wieland, O.; Airoldi, A.; Herskind, B.; Bednarczyk, P.
2004-02-27
The high-energy and discrete {gamma}-ray spectra, as well as the charged particle angular distribution have been measured in the reaction 105 MeV 18O+28Si using the EUROBALL IV, HECTOR and EUCLIDES arrays in order to investigate the predicted Jacobi shape transition in light nuclei. A comparison of the GDR line shape data with the predictions of the thermal shape fluctuation model, based on the most recent rotating liquid drop LSD calculations, shows evidence for such Jacobi shape transition in hot, rapidly rotating 46Ti. The found narrow low-energy component in the GDR line shape is interpreted as the consequence both of the elongated shape and of the Coriolis effect.
Local chiral potentials with Δ-intermediate states and the structure of light nuclei
NASA Astrophysics Data System (ADS)
Piarulli, Maria
2017-01-01
We present a fully local nucleon-nucleon potential in chiral effective field theory (χEFT) retaining pions, nucleons and Δ-isobars as explicit degrees of freedom, and use it in hypersperical-harmonics and quantum Monte Carlo calculations of ground and excited states of 3H, 3He, 4He, 6He, and 6Li nuclei. The calculation of the potential is carried out by including one- and two-pion-exchange contributions up to next-to-next-to-leading order (N2LO) and contact interactions up to next-to-next-to-next-to-leading order (N3LO). The low-energy constants multiplying these contact interactions are fitted to the 2013 Granada database in two different ranges of laboratory energies, either 0-125 MeV or 0-200 MeV, and to the deuteron binding energy and nn singlet scattering length. Fits to these data are performed for three models characterized by long- and short-range cutoffs, RL and RS respectively, ranging from (RL ,RS) =(1 . 2 , 0 . 8) fm down to (0 . 8 , 0 . 6) fm. The long-range (short-range) cutoff regularizes the one- and two-pion exchange (contact) part of the potential.
Local chiral potentials with Δ -intermediate states and the structure of light nuclei
NASA Astrophysics Data System (ADS)
Piarulli, M.; Girlanda, L.; Schiavilla, R.; Kievsky, A.; Lovato, A.; Marcucci, L. E.; Pieper, Steven C.; Viviani, M.; Wiringa, R. B.
2016-11-01
We present fully local versions of the minimally nonlocal nucleon-nucleon potentials constructed in a previous paper [Piarulli et al., Phys. Rev. C 91, 024003 (2015)], 10.1103/PhysRevC.91.024003, and use them in hypersperical harmonics and quantum Monte Carlo calculations of ground and excited states of 3H, 3He, 4He, 6He, and 6Li nuclei. The long-range part of these local potentials includes one- and two-pion exchange contributions without and with Δ isobars in the intermediate states up to order Q3 (Q denotes generically the low momentum scale) in the chiral expansion, while the short-range part consists of contact interactions up to order Q4. The low-energy constants multiplying these contact interactions are fitted to the 2013 Granada database in two different ranges of laboratory energies, either 0-125 MeV or 0-200 MeV, and to the deuteron binding energy and n n singlet scattering length. Fits to these data are performed for three models characterized by long- and short-range cutoffs, RL and RS, respectively, ranging from (RL,RS) =(1.2 ,0.8 ) fm down to (0.8 ,0.6 ) fm. The long-range (short-range) cutoff regularizes the one- and two-pion exchange (contact) part of the potential.
Heavy ion physics in the intermediate energy range with light nuclei
NASA Astrophysics Data System (ADS)
Larochelle, Yves
1997-04-01
Projectile fragmentation can be studied in a wide range of excitation energy despite the fact that the projectile cannot undergo violent collisions to avoid losing its identity. The quality of the source determination allows precise analysis of the decay modes of those hot nuclei formed mainly in peripheral collisions. Results from projectile fragmentation of various system will be presented. Binary processes are dominant in the most peripheral collisions. That dominance persists even for the whole domain of impact parameter and at increasing bombarding energies (Y. Larochelle et al., Phys. Lett. B 352 (1995) 8 and ref. therein). In such a study on the 35Cl - 12C system, for the first time (L. Beaulieu et al., Phys. Rev. Let. 77 (1996) 462) a careful selection of the binary events allowed a direct measurement of the total dissipated energy. Besides that strong binary character, experimental evidence has been presented for the formation of a neck-like structure responsible in part for IMF emission in the Fermi energy domain (Y. Larochelle et al., preprint TASCC-P-96-30, submitted to Phys. Rev. C), from reactions of the 35Cl projectile on two targets: 12C and 197Au. Various dynamical approaches will be discussed in that analysis (X. Qian et al., accepted in Nucl. Phys. A), leading to hypotheses to explain the origin of the neck-like structure.
Asymptotic unbounded root loci - Formulas and computation
NASA Technical Reports Server (NTRS)
Sastry, S. S.; Desoer, C. A.
1983-01-01
A new geometric way of computing the asymptotic behavior of unbounded root loci of a strictly proper linear time-invariant control system as loop gain goes to infinity is presented. Properties of certain restricted linear maps and nested restrictions of linear maps are developed, and formulas are obtained for the leading coefficient of the asymptotic values of the unbounded multivariable root loci are obtained in terms of eigenvalues of those maps. Published results and a certain simple null structure assumption are used to relate these asymptotic values to the structure at infinity of the Smith-McMillan form of the open loop transfer function. Explicit matrix formulas for the more abstract derived formulas are given and additional geometric insights are developed with orthogonal projections and singular value decomposition. Formulas for the pivots of the unbounded root loci are calculated and shown to have the same form as the coefficients of the unbounded asymptotic root loci.
Martian Unbound Water Inventories: Changes with Time
NASA Astrophysics Data System (ADS)
Carr, M. H.; Head, J. W.
2014-07-01
We estimate that approximately 34 m GEL of unbound water is within 100 m of the martian surface today and 60-70 m are estimated for the end of the Hesperian. These estimates are reconciled with the geology.
Asymptotic unbounded root loci - Formulas and computation
NASA Technical Reports Server (NTRS)
Sastry, S. S.; Desoer, C. A.
1983-01-01
A new geometric way of computing the asymptotic behavior of unbounded root loci of a strictly proper linear time-invariant control system as loop gain goes to infinity is presented. Properties of certain restricted linear maps and nested restrictions of linear maps are developed, and formulas are obtained for the leading coefficient of the asymptotic values of the unbounded multivariable root loci are obtained in terms of eigenvalues of those maps. Published results and a certain simple null structure assumption are used to relate these asymptotic values to the structure at infinity of the Smith-McMillan form of the open loop transfer function. Explicit matrix formulas for the more abstract derived formulas are given and additional geometric insights are developed with orthogonal projections and singular value decomposition. Formulas for the pivots of the unbounded root loci are calculated and shown to have the same form as the coefficients of the unbounded asymptotic root loci.
Direct Reactions with Exotic Nuclei
Baur, G.; Typel, S.
2005-10-14
We discuss recent work on Coulomb dissociation and an effective-range theory of low-lying electromagnetic strength of halo nuclei. We propose to study Coulomb dissociation of a halo nucleus bound by a zero-range potential as a homework problem. We study the transition from stripping to bound and unbound states and point out in this context that the Trojan-Horse method is a suitable tool to investigate subthreshold resonances.
Lee, Hyekyung; Baek, Tae Hwa; Park, Meeja; Lee, Seung Yun; Son, Hyun Jin; Kang, Dong Wook; Kim, Joo Heon; Kim, Soo Young
2016-01-01
Background There is subjective disagreement regarding nuclear clearing in papillary thyroid carcinoma. In this study, using digital instruments, we were able to quantify many ambiguous pathologic features and use numeric data to express our findings. Methods We examined 30 papillary thyroid carcinomas. For each case, we selected representative cancer cells showing clear nuclei and surrounding non-neoplastic follicular epithelial cells and evaluated objective values of green light intensity (GLI) for quantitative analysis of nuclear clearing in papillary thyroid carcinoma. Results From 16,274 GLI values from 600 cancer cell nuclei and 13,752 GLI values from 596 non-neoplastic follicular epithelial nuclei, we found a high correlation of 94.9% between GLI and clear nuclei. GLI between the cancer group showing clear nuclei and non-neoplastic follicular epithelia was statistically significant. The overall average level of GLI in the cancer group was over two times higher than the non-neoplastic group despite a wide range of GLI. On a polygonal line graph, there was a fluctuating unique difference between both the cancer and non-neoplastic groups in each patient, which was comparable to the microscopic findings. Conclusions Nuclear GLI could be a useful factor for discriminating between carcinoma cells showing clear nuclei and non-neoplastic follicular epithelia in papillary thyroid carcinoma. PMID:27550048
Lee, Hyekyung; Baek, Tae Hwa; Park, Meeja; Lee, Seung Yun; Son, Hyun Jin; Kang, Dong Wook; Kim, Joo Heon; Kim, Soo Young
2016-09-01
There is subjective disagreement regarding nuclear clearing in papillary thyroid carcinoma. In this study, using digital instruments, we were able to quantify many ambiguous pathologic features and use numeric data to express our findings. We examined 30 papillary thyroid carcinomas. For each case, we selected representative cancer cells showing clear nuclei and surrounding non-neoplastic follicular epithelial cells and evaluated objective values of green light intensity (GLI) for quantitative analysis of nuclear clearing in papillary thyroid carcinoma. From 16,274 GLI values from 600 cancer cell nuclei and 13,752 GLI values from 596 non-neoplastic follicular epithelial nuclei, we found a high correlation of 94.9% between GLI and clear nuclei. GLI between the cancer group showing clear nuclei and non-neoplastic follicular epithelia was statistically significant. The overall average level of GLI in the cancer group was over two times higher than the non-neoplastic group despite a wide range of GLI. On a polygonal line graph, there was a fluctuating unique difference between both the cancer and non-neoplastic groups in each patient, which was comparable to the microscopic findings. Nuclear GLI could be a useful factor for discriminating between carcinoma cells showing clear nuclei and non-neoplastic follicular epithelia in papillary thyroid carcinoma.
Study of resonances produced in light nuclei through two and multi particle correlations
NASA Astrophysics Data System (ADS)
Quattrocchi, L.; Acosta, L.; Amorini, F.; Anzalone, A.; Auditore, L.; Berceanu, I.; Cardella, G.; Chbihi, A.; De Filippo, E.; De Luca, S.; Dell' Aquila, D.; Francalanza, L.; Gnoffo, B.; Grzeszczuk, A.; Lanzalone, G.; Lombardo, I.; Martel, I.; Martorana, N. S.; Minniti, T.; Norella, S.; Pagano, A.; Pagano, E. V.; Papa, M.; Pirrone, S.; Politi, G.; Porto, F.; Rizzo, F.; Rosato, E.; Russotto, P.; Trifirò, A.; Trimarchi, M.; Verde, G.; Veselsky, M.; Vigilante, M.
2017-06-01
CORRELATION experiment has been performed at INFN-LNS of Catania, using the 4π multi-detector CHIMERA, with the aim of exploring correlations between two and multi light particle produced in 12C+24Mg collisions at 35 AMeV. Particular attention has been paid to the decay mechanisms of Hoyle state, an excited resonant state of 12C produced via the triple-α process and characterized by a pronounced molecular like structure with three α particles. The study of the Hoyle state is essential for nucleosynthesis, but it also represents a clearly isolated state that can be studied as a three-α cluster system.
NASA Astrophysics Data System (ADS)
Bystritsky, V. M.; Bystritsky, Vit. M.; Dudkin, G. N.; Nechaev, B. A.; Padalko, V. N.
2017-07-01
The factors defining the constraints on the current characteristics of the magnetically insulated ion diode (IDM) are considered. The specific current parameters close to the maximum possible ones are obtained for the particular IDM-40 design assigned for acceleration of light ions and investigation of nuclear reactions with small cross sections in the astrophysical energy range (2-40 keV) in the entrance channel. It is experimentally demonstrated that the chosen optimal operation conditions for IDM-40 units provide high stability of the parameters (energy distribution and composition of accelerated particle beams, degree of neutralization) of the accelerated particle flux, which increases during the working pulse.
Measurement of light charged particles in the decay channels of medium-mass excited compound nuclei
NASA Astrophysics Data System (ADS)
Valdré, S.; Barlini, S.; Casini, G.; Pasquali, G.; Piantelli, S.; Carboni, S.; Cinausero, M.; Gramegna, F.; Marchi, T.; Baiocco, G.; Bardelli, L.; Benzoni, G.; Bini, M.; Blasi, N.; Bracco, A.; Brambilla, S.; Bruno, M.; Camera, F.; Corsi, A.; Crespi, F.; D'Agostino, M.; Degerlier, M.; Kravchuk, V. L.; Leoni, S.; Million, B.; Montanari, D.; Morelli, L.; Nannini, A.; Nicolini, R.; Poggi, G.; Vannini, G.; Wieland, O.; Bednarczyk, P.; Ciemała, M.; Dudek, J.; Fornal, B.; Kmiecik, M.; Maj, A.; Matejska-Minda, M.; Mazurek, K.; Męczyński, W. M.; Myalski, S.; Styczeń, J.; Ziębliński, M.
2014-03-01
The 48Ti on 40Ca reactions have been studied at 300 and 600 MeV focusing on the fusion-evaporation (FE) and fusion-fission (FF) exit channels. Energy spectra and multiplicities of the emitted light charged particles have been compared to Monte Carlo simulations based on the statistical model. Indeed, in this mass region (A ~ 100) models predict that shape transitions can occur at high spin values and relatively scarce data exist in the literature about coincidence measurements between evaporation residues and light charged particles. Signals of shape transitions can be found in the variations of the lineshape of high energy gamma rays emitted from the de-excitation of GDR states gated on different region of angular momenta. For this purpose it is important to keep under control the FE and FF processes, to regulate the statistical model parameters and to control the onset of possible pre-equilibrium emissions from 300 to 600 MeV bombarding energy.
Reverberation mapping the torus in 12 Active Galactic Nuclei using Spitzer and optical light curves
NASA Astrophysics Data System (ADS)
Robinson, A.
2015-09-01
We present results from a ~2.5 year monitoring campaign using the Spitzer Space Telescope during its "warm" mission. 12 low-redshift broad-line AGN were observed at 3.6 and 4.5 microns, with a 3 day cadence during the first 17 months and a 30 day cadence for the remaining 12 months. Contemporaneous optical observations were also obtained from several ground-based telescopes. Significant IR variability was observed in 11 of the 12 objects, with typical timescales ~100 days and relative amplitudes ranging from ~10% to ~100%. We present cross-correlation analyses of the IR and optical light curves for the sample as a whole and discuss in detail the case of NGC6418, which exhibits the largest variability amplitude. In this object, the IR-optical lag implies that the dust emitting at 3.6 and 4.5 microns is located at a distance 1 light-month from the source of the AGN UV--optical continuum. This is consistent with the inferred lower limit to the sublimation radius for pure graphite grains at 1800 K, but smaller by a factor of ~2 than the corresponding lower limit for a "standard" ISM dust composition.
Zhang, S.; Zu, Z.; Chen, J.H., Ma, Y.G., Cai, X-Z, Ma, G.L., Zhong, C.
2011-08-01
High-energy heavy-ion collisions produce abundant hyperons and nucleons. A dynamical coalescence model coupled with the ART model is employed to study the production probabilities of light clusters, deuteron (d), triton (t), helion ({sup 3}He), and hypertriton ({sub {Lambda}}{sup 3}H) at subthreshold energy of Aproduction ({approx} 1 GeV per nucleon). We study the dependence on the reaction system size of the coalescence penalty factor per additional nucleon and entropy per nucleon. The Strangeness Population Factor (S{sub 3} = {sup 3}{sub {Lambda}}H/({sup 3}He x {Lambda}/p)) shows an extra suppression of hypertriton comparing to light clusters of the same mass number. This model predicts a hypertriton production cross-section of a few {mu}b in {sup 36}Ar+{sup 36}Ar, {sup 40}Ca+{sup 40}Ca and {sup 56}Ni+{sup 56}Ni in 1 A GeV reactions. The production rate is as high as a few hypertritons per million collisions, which shows that the fixed-target heavy-ion collisions at CSR (Lanzhou/China) at {Lambda} subthreshold energy are suitable for breaking new ground in hypernuclear physics.
Particle decay of proton-unbound levels in 12N
NASA Astrophysics Data System (ADS)
Chipps, K. A.; Pain, S. D.; Greife, U.; Kozub, R. L.; Nesaraja, C. D.; Smith, M. S.; Bardayan, D. W.; Kontos, A.; Linhardt, L. E.; Matos, M.; Pittman, S. T.; Thompson, P.; Jensa Collaboration
2017-04-01
Background: Transfer reactions are a useful tool for studying nuclear structure, particularly in the regime of low level densities and strong single-particle strengths. In addition, transfer reactions can populate levels above particle decay thresholds, allowing for the possibility of studying the subsequent decays and furthering our understanding of the nuclei being probed. In particular, the decay of loosely bound nuclei such as 12N can help inform and improve structure models. Purpose: To learn about the decay of excited states in 12N, to more generally inform nuclear structure models, particularly in the case of particle-unbound levels in low-mass systems which are within the reach of state-of-the-art ab initio calculations. Method: In this follow-up analysis of previously published data [Chipps et al. (JENSA Collaboration), Phys. Rev. C 92, 034325 (2015)], 10.1103/PhysRevC.92.034325, decay particles from excited states populated in 12N have been detected in coincidence with tritons from the 14N(p ,t )12N transfer reaction. Specifically, decay protons from proton-unbound levels above ˜2 MeV excitation energy were observed by utilizing the Jet Experiments in Nuclear Structure and Astrophysics (JENSA) gas jet target. Results: Isotropic proton branching ratios for the p 0 and p 1 decay channels are calculated and decay particle spectra for the populated levels from p 0 , p 1 , and p 2 decay are given. Conclusions: The current data from 14N(p ,t )12N will help provide nuclear structure and decay information input to models in this mass region.
Investigation of the low-energy kaons hadronic interactions in light nuclei by AMADEUS
NASA Astrophysics Data System (ADS)
Piscicchia, K.; Cargnelli, M.; Curceanu, C.; Del Grande, R.; Fabbietti, L.; Marton, J.; Scordo, A.; Sirghi, D.; Tucakovic, I.; Vazquez Doce, O.; Wycech, S.; Zmeskal, J.; Mandaglio, G.; Martini, M.; Moskal, P.
2017-03-01
The AMADEUS experiment aims to provide unique quality data of K- hadronic interactions with light nuclear targets, in order to solve fundamental open questions in the non-perturbative strangeness QCD sector, like the controversial nature of the Λ(1405) state, the yield of hyperon formation below threshold, the yield and shape of multi-nucleon K- absorption, processes which are intimately connected to the possible existence of exotic antikaon multi-nucleon clusters. AMADEUS takes advantage of the DAΦNE collider, which provides a unique source of monochromatic low-momentum kaons and exploits the KLOE detector as an active target, in order to obtain excellent acceptance and resolution data for K- nuclear capture on H, 4He, 9Be and 12C, both at-rest and in-flight.
Two-proton decay from Isobaric Analog States of light nuclei
NASA Astrophysics Data System (ADS)
Brown, Kyle
2014-03-01
Recent experiments at the National Superconducting Cyclotron Laboratory at Michigan State University using the charged-particle array HiRA and the gamma-ray array CAESAR have shed light on a new class of two-proton emitters associated with Isobaric Analog States (IAS). The two-proton decay is to the Isobaric Analog state of the daughter, which then gamma decays. These isospin-allowed transitions occur when one-proton decays are forbidden by either energy or isospin conservation, and when two-proton decay to the ground state is isospin forbidden. Three possible examples of this decay path will be discussed (8BIAS, 12NIAS, and 16FIAS) . The known IAS of 8C in 8B was confirmed to decay by two-proton emission to the 3.56 MeV IAS in 6Li. While the IAS in 8B was previously known, it was measured in this experiment with unbiased statistics and in coincidence with the 3.56 MeV gamma-ray. The IAS in 16F was investigated for the first time in this experiment and is still under investigation. Previous work on the IAS of 12O in 12N at the Cyclotron Institute at Texas A&M will also be presented.
Generalized Categorial Grammar for Unbounded Dependencies Recovery
ERIC Educational Resources Information Center
Nguyen, Luan Viet
2014-01-01
Accurate recovery of predicate-argument dependencies is vital for interpretation tasks like information extraction and question answering, and unbounded dependencies may account for a significant portion of the dependencies in any given text. This thesis describes a Generalized Categorial Grammar (GCG) which, like other categorial grammars,…
Generalized Categorial Grammar for Unbounded Dependencies Recovery
ERIC Educational Resources Information Center
Nguyen, Luan Viet
2014-01-01
Accurate recovery of predicate-argument dependencies is vital for interpretation tasks like information extraction and question answering, and unbounded dependencies may account for a significant portion of the dependencies in any given text. This thesis describes a Generalized Categorial Grammar (GCG) which, like other categorial grammars,…
Unbounded orbits of a swinging Atwood's machine
NASA Astrophysics Data System (ADS)
Tufillaro, N.; Nunes, A.; Casasayas, J.
1988-12-01
The motion of a swinging Atwood's machine is examined when the orbits are unbounded. Expressions for the asymptotic behavior of the orbits are derived that exhibit either an infinite number of oscillations or no oscillations, depending only on a critical value of the mass ratio.
Coupled-cluster computations of atomic nuclei.
Hagen, G; Papenbrock, T; Hjorth-Jensen, M; Dean, D J
2014-09-01
In the past decade, coupled-cluster theory has seen a renaissance in nuclear physics, with computations of neutron-rich and medium-mass nuclei. The method is efficient for nuclei with product-state references, and it describes many aspects of weakly bound and unbound nuclei. This report reviews the technical and conceptual developments of this method in nuclear physics, and the results of coupled-cluster calculations for nucleonic matter, and for exotic isotopes of helium, oxygen, calcium, and some of their neighbors.
Adam, J.; Adamová, D.; Aggarwal, M. M.; ...
2016-02-29
The production of (anti-)deuteron and (anti-) 3He nuclei in Pb-Pb collisions at √sNN = 2.76 TeV has been studied using the ALICE detector at the LHC. The spectra exhibit a significant hardening with increasing centrality. Combined blast-wave fits of several particles support the interpretation that this behavior is caused by an increase of radial flow. The integrated particle yields are discussed in the context of coalescence and thermal-statistical model expectations. The particle ratios, 3He /d and 3He /p, in Pb-Pb collisions are found to be in agreement with a common chemical freeze-out temperature of Tchem ≈ 156 MeV. These ratiosmore » do not vary with centrality which is in agreement with the thermal-statistical model. In a coalescence approach, it excludes models in which nucleus production is proportional to the particle multiplicity and favors those in which it is proportional to the particle density instead. In addition, the observation of 31 anti-tritons in Pb-Pb collisions is reported. For comparison, the deuteron spectrum in pp collisions at √s = 7 TeV is also presented. While the p/π ratio is similar in pp and Pb-Pb collisions, the d/p ratio in pp collisions is found to be lower by a factor of 2.2 than in Pb-Pb collisions.« less
NASA Astrophysics Data System (ADS)
Adam, J.; Adamová, D.; Aggarwal, M. M.; Aglieri Rinella, G.; Agnello, M.; Agrawal, N.; Ahammed, Z.; Ahmed, I.; Ahn, S. U.; Aimo, I.; Aiola, S.; Ajaz, M.; Akindinov, A.; Alam, S. N.; Aleksandrov, D.; Alessandro, B.; Alexandre, D.; Alfaro Molina, R.; Alici, A.; Alkin, A.; Alme, J.; Alt, T.; Altinpinar, S.; Altsybeev, I.; Alves Garcia Prado, C.; Andrei, C.; Andronic, A.; Anguelov, V.; Anielski, J.; Antičić, T.; Antinori, F.; Antonioli, P.; Aphecetche, L.; Appelshäuser, H.; Arcelli, S.; Armesto, N.; Arnaldi, R.; Aronsson, T.; Arsene, I. C.; Arslandok, M.; Augustinus, A.; Averbeck, R.; Azmi, M. D.; Bach, M.; Badalà, A.; Baek, Y. W.; Bagnasco, S.; Bailhache, R.; Bala, R.; Baldisseri, A.; Ball, M.; Baltasar Dos Santos Pedrosa, F.; Baral, R. C.; Barbano, A. M.; Barbera, R.; Barile, F.; Barnaföldi, G. G.; Barnby, L. S.; Barret, V.; Bartalini, P.; Bartke, J.; Bartsch, E.; Basile, M.; Bastid, N.; Basu, S.; Bathen, B.; Batigne, G.; Batista Camejo, A.; Batyunya, B.; Batzing, P. C.; Bearden, I. G.; Beck, H.; Bedda, C.; Behera, N. K.; Belikov, I.; Bellini, F.; Bello Martinez, H.; Bellwied, R.; Belmont, R.; Belmont-Moreno, E.; Belyaev, V.; Bencedi, G.; Beole, S.; Berceanu, I.; Bercuci, A.; Berdnikov, Y.; Berenyi, D.; Bertens, R. A.; Berzano, D.; Betev, L.; Bhasin, A.; Bhat, I. R.; Bhati, A. K.; Bhattacharjee, B.; Bhom, J.; Bianchi, L.; Bianchi, N.; Bianchin, C.; Bielčík, J.; Bielčíková, J.; Bilandzic, A.; Biswas, S.; Bjelogrlic, S.; Blanco, F.; Blau, D.; Blume, C.; Bock, F.; Bogdanov, A.; Bøggild, H.; Boldizsár, L.; Bombara, M.; Book, J.; Borel, H.; Borissov, A.; Borri, M.; Bossú, F.; Botje, M.; Botta, E.; Böttger, S.; Braun-Munzinger, P.; Bregant, M.; Breitner, T.; Broker, T. A.; Browning, T. A.; Broz, M.; Brucken, E. J.; Bruna, E.; Bruno, G. E.; Budnikov, D.; Buesching, H.; Bufalino, S.; Buncic, P.; Busch, O.; Buthelezi, Z.; Buxton, J. T.; Caffarri, D.; Cai, X.; Caines, H.; Calero Diaz, L.; Caliva, A.; Calvo Villar, E.; Camerini, P.; Carena, F.; Carena, W.; Castillo Castellanos, J.; Castro, A. J.; Casula, E. A. R.; Cavicchioli, C.; Ceballos Sanchez, C.; Cepila, J.; Cerello, P.; Chang, B.; Chapeland, S.; Chartier, M.; Charvet, J. L.; Chattopadhyay, S.; Chattopadhyay, S.; Chelnokov, V.; Cherney, M.; Cheshkov, C.; Cheynis, B.; Chibante Barroso, V.; Chinellato, D. D.; Chochula, P.; Choi, K.; Chojnacki, M.; Choudhury, S.; Christakoglou, P.; Christensen, C. H.; Christiansen, P.; Chujo, T.; Chung, S. U.; Cicalo, C.; Cifarelli, L.; Cindolo, F.; Cleymans, J.; Colamaria, F.; Colella, D.; Collu, A.; Colocci, M.; Conesa Balbastre, G.; Conesa Del Valle, Z.; Connors, M. E.; Contreras, J. G.; Cormier, T. M.; Corrales Morales, Y.; Cortés Maldonado, I.; Cortese, P.; Cosentino, M. R.; Costa, F.; Crochet, P.; Cruz Albino, R.; Cuautle, E.; Cunqueiro, L.; Dahms, T.; Dainese, A.; Danu, A.; Das, D.; Das, I.; Das, S.; Dash, A.; Dash, S.; de, S.; de Caro, A.; de Cataldo, G.; de Cuveland, J.; de Falco, A.; de Gruttola, D.; De Marco, N.; de Pasquale, S.; Deisting, A.; Deloff, A.; Dénes, E.; D'Erasmo, G.; di Bari, D.; di Mauro, A.; di Nezza, P.; Diaz Corchero, M. A.; Dietel, T.; Dillenseger, P.; Divià, R.; Djuvsland, Ø.; Dobrin, A.; Dobrowolski, T.; Domenicis Gimenez, D.; Dönigus, B.; Dordic, O.; Dubey, A. K.; Dubla, A.; Ducroux, L.; Dupieux, P.; Ehlers, R. J.; Elia, D.; Engel, H.; Erazmus, B.; Erhardt, F.; Eschweiler, D.; Espagnon, B.; Estienne, M.; Esumi, S.; Eum, J.; Evans, D.; Evdokimov, S.; Eyyubova, G.; Fabbietti, L.; Fabris, D.; Faivre, J.; Fantoni, A.; Fasel, M.; Feldkamp, L.; Felea, D.; Feliciello, A.; Feofilov, G.; Ferencei, J.; Fernández Téllez, A.; Ferreiro, E. G.; Ferretti, A.; Festanti, A.; Figiel, J.; Figueredo, M. A. S.; Filchagin, S.; Finogeev, D.; Fionda, F. M.; Fiore, E. M.; Fleck, M. G.; Floris, M.; Foertsch, S.; Foka, P.; Fokin, S.; Fragiacomo, E.; Francescon, A.; Frankenfeld, U.; Fuchs, U.; Furget, C.; Furs, A.; Fusco Girard, M.; Gaardhøje, J. J.; Gagliardi, M.; Gago, A. M.; Gallio, M.; Gangadharan, D. R.; Ganoti, P.; Gao, C.; Garabatos, C.; Garcia-Solis, E.; Gargiulo, C.; Gasik, P.; Germain, M.; Gheata, A.; Gheata, M.; Ghosh, P.; Ghosh, S. K.; Gianotti, P.; Giubellino, P.; Giubilato, P.; Gladysz-Dziadus, E.; Glässel, P.; Goméz Coral, D. M.; Gomez Ramirez, A.; González-Zamora, P.; Gorbunov, S.; Görlich, L.; Gotovac, S.; Grabski, V.; Graczykowski, L. K.; Grelli, A.; Grigoras, A.; Grigoras, C.; Grigoriev, V.; Grigoryan, A.; Grigoryan, S.; Grinyov, B.; Grion, N.; Grosse-Oetringhaus, J. F.; Grossiord, J.-Y.; Grosso, R.; Guber, F.; Guernane, R.; Guerzoni, B.; Gulbrandsen, K.; Gulkanyan, H.; Gunji, T.; Gupta, A.; Gupta, R.; Haake, R.; Haaland, Ø.; Hadjidakis, C.; Haiduc, M.; Hamagaki, H.; Hamar, G.; Hanratty, L. D.; Hansen, A.; Harris, J. W.; Hartmann, H.; Harton, A.; Hatzifotiadou, D.; Hayashi, S.; Heckel, S. T.; Heide, M.; Helstrup, H.; Herghelegiu, A.; Herrera Corral, G.; Hess, B. A.; Hetland, K. F.; Hilden, T. E.; Hillemanns, H.; Hippolyte, B.; Hristov, P.; Huang, M.; Humanic, T. J.; Hussain, N.; Hussain, T.; Hutter, D.; Hwang, D. S.; Ilkaev, R.; Ilkiv, I.; Inaba, M.; Ionita, C.; Ippolitov, M.; Irfan, M.; Ivanov, M.; Ivanov, V.; Izucheev, V.; Jacobs, P. M.; Jahnke, C.; Jang, H. J.; Janik, M. A.; Jayarathna, P. H. S. Y.; Jena, C.; Jena, S.; Jimenez Bustamante, R. T.; Jones, P. G.; Jung, H.; Jusko, A.; Kalinak, P.; Kalweit, A.; Kamin, J.; Kang, J. H.; Kaplin, V.; Kar, S.; Karasu Uysal, A.; Karavichev, O.; Karavicheva, T.; Karpechev, E.; Kebschull, U.; Keidel, R.; Keijdener, D. L. D.; Keil, M.; Khan, K. H.; Mohisin Khan, M.; Khan, P.; Khan, S. A.; Khanzadeev, A.; Kharlov, Y.; Kileng, B.; Kim, B.; Kim, D. W.; Kim, D. J.; Kim, H.; Kim, J. S.; Kim, M.; Kim, M.; Kim, S.; Kim, T.; Kirsch, S.; Kisel, I.; Kiselev, S.; Kisiel, A.; Kiss, G.; Klay, J. L.; Klein, C.; Klein, J.; Klein-Bösing, C.; Kluge, A.; Knichel, M. L.; Knospe, A. G.; Kobayashi, T.; Kobdaj, C.; Kofarago, M.; Köhler, M. K.; Kollegger, T.; Kolojvari, A.; Kondratiev, V.; Kondratyeva, N.; Kondratyuk, E.; Konevskikh, A.; Kour, M.; Kouzinopoulos, C.; Kovalenko, O.; Kovalenko, V.; Kowalski, M.; Kox, S.; Koyithatta Meethaleveedu, G.; Kral, J.; Králik, I.; Kravčáková, A.; Krelina, M.; Kretz, M.; Krivda, M.; Krizek, F.; Kryshen, E.; Krzewicki, M.; Kubera, A. M.; Kučera, V.; Kucheriaev, Y.; Kugathasan, T.; Kuhn, C.; Kuijer, P. G.; Kulakov, I.; Kumar, A.; Kumar, J.; Kumar, L.; Kurashvili, P.; Kurepin, A.; Kurepin, A. B.; Kuryakin, A.; Kushpil, S.; Kweon, M. J.; Kwon, Y.; La Pointe, S. L.; La Rocca, P.; Lagana Fernandes, C.; Lakomov, I.; Langoy, R.; Lara, C.; Lardeux, A.; Lattuca, A.; Laudi, E.; Lea, R.; Leardini, L.; Lee, G. R.; Lee, S.; Legrand, I.; Lehnert, J.; Lemmon, R. C.; Lenti, V.; Leogrande, E.; León Monzón, I.; Leoncino, M.; Lévai, P.; Li, S.; Li, X.; Lien, J.; Lietava, R.; Lindal, S.; Lindenstruth, V.; Lippmann, C.; Lisa, M. A.; Ljunggren, H. M.; Lodato, D. F.; Loenne, P. I.; Loggins, V. R.; Loginov, V.; Loizides, C.; Lopez, X.; López Torres, E.; Lowe, A.; Lu, X.-G.; Luettig, P.; Lunardon, M.; Luparello, G.; Maevskaya, A.; Mager, M.; Mahajan, S.; Mahmood, S. M.; Maire, A.; Majka, R. D.; Malaev, M.; Maldonado Cervantes, I.; Malinina, L.; Mal'Kevich, D.; Malzacher, P.; Mamonov, A.; Manceau, L.; Manko, V.; Manso, F.; Manzari, V.; Marchisone, M.; Mareš, J.; Margagliotti, G. V.; Margotti, A.; Margutti, J.; Marín, A.; Markert, C.; Marquard, M.; Martin, N. A.; Martin Blanco, J.; Martinengo, P.; Martínez, M. I.; Martínez García, G.; Martinez Pedreira, M.; Martynov, Y.; Mas, A.; Masciocchi, S.; Masera, M.; Masoni, A.; Massacrier, L.; Mastroserio, A.; Masui, H.; Matyja, A.; Mayer, C.; Mazer, J.; Mazzoni, M. A.; McDonald, D.; Meddi, F.; Menchaca-Rocha, A.; Meninno, E.; Mercado Pérez, J.; Meres, M.; Miake, Y.; Mieskolainen, M. M.; Mikhaylov, K.; Milano, L.; Milosevic, J.; Minervini, L. M.; Mischke, A.; Mishra, A. N.; Miśkowiec, D.; Mitra, J.; Mitu, C. M.; Mohammadi, N.; Mohanty, B.; Molnar, L.; Montaño Zetina, L.; Montes, E.; Morando, M.; Moreira de Godoy, D. A.; Moreno, L. A. P.; Moretto, S.; Morreale, A.; Morsch, A.; Muccifora, V.; Mudnic, E.; Mühlheim, D.; Muhuri, S.; Mukherjee, M.; Müller, H.; Mulligan, J. D.; Munhoz, M. G.; Murray, S.; Musa, L.; Musinsky, J.; Nandi, B. K.; Nania, R.; Nappi, E.; Naru, M. U.; Nattrass, C.; Nayak, K.; Nayak, T. K.; Nazarenko, S.; Nedosekin, A.; Nellen, L.; Ng, F.; Nicassio, M.; Niculescu, M.; Niedziela, J.; Nielsen, B. S.; Nikolaev, S.; Nikulin, S.; Nikulin, V.; Noferini, F.; Nomokonov, P.; Nooren, G.; Norman, J.; Nyanin, A.; Nystrand, J.; Oeschler, H.; Oh, S.; Oh, S. K.; Ohlson, A.; Okatan, A.; Okubo, T.; Olah, L.; Oleniacz, J.; Oliveira da Silva, A. C.; Oliver, M. H.; Onderwaater, J.; Oppedisano, C.; Ortiz Velasquez, A.; Oskarsson, A.; Otwinowski, J.; Oyama, K.; Ozdemir, M.; Pachmayer, Y.; Pagano, P.; Paić, G.; Pajares, C.; Pal, S. K.; Pan, J.; Pandey, A. K.; Pant, D.; Papikyan, V.; Pappalardo, G. S.; Pareek, P.; Park, W. J.; Parmar, S.; Passfeld, A.; Paticchio, V.; Paul, B.; Pawlak, T.; Peitzmann, T.; Pereira da Costa, H.; Pereira de Oliveira Filho, E.; Peresunko, D.; Pérez Lara, C. E.; Peskov, V.; Pestov, Y.; Petráček, V.; Petrov, V.; Petrovici, M.; Petta, C.; Piano, S.; Pikna, M.; Pillot, P.; Pinazza, O.; Pinsky, L.; Piyarathna, D. B.; Płoskoń, M.; Planinic, M.; Pluta, J.; Pochybova, S.; Podesta-Lerma, P. L. M.; Poghosyan, M. G.; Polichtchouk, B.; Poljak, N.; Poonsawat, W.; Pop, A.; Porteboeuf-Houssais, S.; Porter, J.; Pospisil, J.; Prasad, S. K.; Preghenella, R.; Prino, F.; Pruneau, C. A.; Pshenichnov, I.; Puccio, M.; Puddu, G.; Pujahari, P.; Punin, V.; Putschke, J.; Qvigstad, H.; Rachevski, A.; Raha, S.; Rajput, S.; Rak, J.; Rakotozafindrabe, A.; Ramello, L.; Raniwala, R.; Raniwala, S.; Räsänen, S. S.; Rascanu, B. T.; Rathee, D.; Read, K. F.; Real, J. S.; Redlich, K.; Reed, R. J.; Rehman, A.; Reichelt, P.; Reicher, M.; Reidt, F.; Ren, X.; Renfordt, R.; Reolon, A. R.; Reshetin, A.; Rettig, F.; Revol, J.-P.; Reygers, K.; Riabov, V.; Ricci, R. A.; Richert, T.; Richter, M.; Riedler, P.; Riegler, W.; Riggi, F.; Ristea, C.; Rivetti, A.; Rocco, E.; Rodríguez Cahuantzi, M.; Rodriguez Manso, A.; Røed, K.; Rogochaya, E.; Rohr, D.; Röhrich, D.; Romita, R.; Ronchetti, F.; Ronflette, L.; Rosnet, P.; Rossi, A.; Roukoutakis, F.; Roy, A.; Roy, C.; Roy, P.; Rubio Montero, A. J.; Rui, R.; Russo, R.; Ryabinkin, E.; Ryabov, Y.; Rybicki, A.; Sadovsky, S.; Šafařík, K.; Sahlmuller, B.; Sahoo, P.; Sahoo, R.; Sahoo, S.; Sahu, P. K.; Saini, J.; Sakai, S.; Saleh, M. A.; Salgado, C. A.; Salzwedel, J.; Sambyal, S.; Samsonov, V.; Sanchez Castro, X.; Šándor, L.; Sandoval, A.; Sano, M.; Santagati, G.; Sarkar, D.; Scapparone, E.; Scarlassara, F.; Scharenberg, R. P.; Schiaua, C.; Schicker, R.; Schmidt, C.; Schmidt, H. R.; Schuchmann, S.; Schukraft, J.; Schulc, M.; Schuster, T.; Schutz, Y.; Schwarz, K.; Schweda, K.; Scioli, G.; Scomparin, E.; Scott, R.; Seeder, K. S.; Seger, J. E.; Sekiguchi, Y.; Selyuzhenkov, I.; Senosi, K.; Seo, J.; Serradilla, E.; Sevcenco, A.; Shabanov, A.; Shabetai, A.; Shadura, O.; Shahoyan, R.; Shangaraev, A.; Sharma, A.; Sharma, M.; Sharma, N.; Shigaki, K.; Shtejer, K.; Sibiriak, Y.; Siddhanta, S.; Sielewicz, K. M.; Siemiarczuk, T.; Silvermyr, D.; Silvestre, C.; Simatovic, G.; Simonetti, G.; Singaraju, R.; Singh, R.; Singha, S.; Singhal, V.; Sinha, B. C.; Sinha, T.; Sitar, B.; Sitta, M.; Skaali, T. B.; Slupecki, M.; Smirnov, N.; Snellings, R. J. M.; Snellman, T. W.; Søgaard, C.; Soltz, R.; Song, J.; Song, M.; Song, Z.; Soramel, F.; Sorensen, S.; Spacek, M.; Spiriti, E.; Sputowska, I.; Spyropoulou-Stassinaki, M.; Srivastava, B. K.; Stachel, J.; Stan, I.; Stefanek, G.; Steinpreis, M.; Stenlund, E.; Steyn, G.; Stiller, J. H.; Stocco, D.; Strmen, P.; Suaide, A. A. P.; Sugitate, T.; Suire, C.; Suleymanov, M.; Sultanov, R.; Šumbera, M.; Symons, T. J. M.; Szabo, A.; Szanto de Toledo, A.; Szarka, I.; Szczepankiewicz, A.; Szymanski, M.; Takahashi, J.; Tanaka, N.; Tangaro, M. A.; Tapia Takaki, J. D.; Tarantola Peloni, A.; Tariq, M.; Tarzila, M. G.; Tauro, A.; Tejeda Muñoz, G.; Telesca, A.; Terasaki, K.; Terrevoli, C.; Teyssier, B.; Thäder, J.; Thomas, D.; Tieulent, R.; Timmins, A. R.; Toia, A.; Trogolo, S.; Trubnikov, V.; Trzaska, W. H.; Tsuji, T.; Tumkin, A.; Turrisi, R.; Tveter, T. S.; Ullaland, K.; Uras, A.; Usai, G. L.; Utrobicic, A.; Vajzer, M.; Vala, M.; Valencia Palomo, L.; Vallero, S.; van der Maarel, J.; van Hoorne, J. W.; van Leeuwen, M.; Vanat, T.; Vande Vyvre, P.; Varga, D.; Vargas, A.; Vargyas, M.; Varma, R.; Vasileiou, M.; Vasiliev, A.; Vauthier, A.; Vechernin, V.; Veen, A. M.; Veldhoen, M.; Velure, A.; Venaruzzo, M.; Vercellin, E.; Vergara Limón, S.; Vernet, R.; Verweij, M.; Vickovic, L.; Viesti, G.; Viinikainen, J.; Vilakazi, Z.; Villalobos Baillie, O.; Villatoro Tello, A.; Vinogradov, A.; Vinogradov, L.; Vinogradov, Y.; Virgili, T.; Vislavicius, V.; Viyogi, Y. P.; Vodopyanov, A.; Völkl, M. A.; Voloshin, K.; Voloshin, S. A.; Volpe, G.; von Haller, B.; Vorobyev, I.; Vranic, D.; Vrláková, J.; Vulpescu, B.; Vyushin, A.; Wagner, B.; Wagner, J.; Wang, H.; Wang, M.; Wang, Y.; Watanabe, D.; Weber, M.; Weber, S. G.; Wessels, J. P.; Westerhoff, U.; Wiechula, J.; Wikne, J.; Wilde, M.; Wilk, G.; Wilkinson, J.; Williams, M. C. S.; Windelband, B.; Winn, M.; Yaldo, C. G.; Yamaguchi, Y.; Yang, H.; Yang, P.; Yano, S.; Yasnopolskiy, S.; Yin, Z.; Yokoyama, H.; Yoo, I.-K.; Yurchenko, V.; Yushmanov, I.; Zaborowska, A.; Zaccolo, V.; Zaman, A.; Zampolli, C.; Zanoli, H. J. C.; Zaporozhets, S.; Zarochentsev, A.; Závada, P.; Zaviyalov, N.; Zbroszczyk, H.; Zgura, I. S.; Zhalov, M.; Zhang, H.; Zhang, X.; Zhang, Y.; Zhao, C.; Zhigareva, N.; Zhou, D.; Zhou, Y.; Zhou, Z.; Zhu, H.; Zhu, J.; Zhu, X.; Zichichi, A.; Zimmermann, A.; Zimmermann, M. B.; Zinovjev, G.; Zyzak, M.; Alice Collaboration
2016-02-01
The production of (anti-)deuteron and (anti-)3He nuclei in Pb-Pb collisions at √{sNN}=2.76 TeV has been studied using the ALICE detector at the LHC. The spectra exhibit a significant hardening with increasing centrality. Combined blast-wave fits of several particles support the interpretation that this behavior is caused by an increase of radial flow. The integrated particle yields are discussed in the context of coalescence and thermal-statistical model expectations. The particle ratios, 3He/d and 3He/p, in Pb-Pb collisions are found to be in agreement with a common chemical freeze-out temperature of Tchem≈156 MeV. These ratios do not vary with centrality which is in agreement with the thermal-statistical model. In a coalescence approach, it excludes models in which nucleus production is proportional to the particle multiplicity and favors those in which it is proportional to the particle density instead. In addition, the observation of 31 anti-tritons in Pb-Pb collisions is reported. For comparison, the deuteron spectrum in p p collisions at √{s }=7 TeV is also presented. While the p /π ratio is similar in p p and Pb-Pb collisions, the d /p ratio in p p collisions is found to be lower by a factor of 2.2 than in Pb-Pb collisions.
Two-term formula for ground band energy symmetry in low-lying levels of light Mg-Zr nuclei
NASA Astrophysics Data System (ADS)
Devi, Vidya
2015-12-01
In this paper, two parameter single-term energy formula EJ = aJb is used to study the energy spin relationship within the ground bands of even-even Mg-Zr nuclei. The formula works better for the γ-soft nuclei as well as vibrational nuclei. We also compared it with other two-parameter formulas: Ejiri, ab, pq and soft rotor formula (SRF). We also study the symmetry of the nuclei in the framework of interacting boson model (IBM-1). The IBM-1 was employed to determine the most appropriate Hamiltonian, the Hamiltonian of the IBM-1 and O(6) symmetry calculation, for the study of these isotopes. We have also calculated energy levels and B(E2) values for number of transitions in these 76-78Se and 76-78Kr isotopes and there is a good agreement between the presented results and the previous experimental data.
Abramov, B. M.; Borodin, Yu. A.; Bulychjov, S. A.; Dukhovskoy, I. A.; Krutenkova, A. P.; Kulikov, V. V. Martemianov, M. A.; Matsuk, M. A.; Tarasov, V. E.; Turdakina, E. N.; Khanov, A. I.
2007-07-15
Quasielastic deuteron and triton knockout from {sup 12}C and {sup 16}O nuclei has been studied infull kinematics using a 0.72-GeV/c pion beam. The momentum distributions of the intranuclear quasideuteron motion, excitation-energy spectra of the residual nuclei, and the effective numbers N{sub d}{sup eff} of quasideuterons are determined. The parameters of the quasideuteron intranuclear motion are in reasonable agreement with the results obtained in other beams. The N{sub d}{sup eff} in the nuclei from {sup 6}Li to {sup 16}O measured in full kinematics are virtually independent of the atomic number in contrast to the analogous values in the inclusive deuteron-knockout reaction induced by protons. The phenomenon of triton knockout from these nuclei is observed, which makes possible estimation of the cross section of backward pion-triton elastic scattering in yet unexplored regions of energy and momentum transfer.
Unbounded random operators and Feynman formulae
NASA Astrophysics Data System (ADS)
Orlov, Yu. N.; Sakbaev, V. Zh.; Smolyanov, O. G.
2016-12-01
We introduce and study probabilistic interpolations of various quantization methods. To do this, we develop a method for finding the expectations of unbounded random operators on a Hilbert space by averaging (with the help of Feynman formulae) the random one-parameter semigroups generated by these operators (the usual method for finding the expectations of bounded random operators is generally inapplicable to unbounded ones). Although the averaging of families of semigroups generates a function that need not possess the semigroup property, the Chernoff iterates of this function approximate a certain semigroup, whose generator is taken for the expectation of the original random operator. In the case of bounded random operators, this expectation coincides with the ordinary one.
Vuillez, P; Jacob, N; Teclemariam-Mesbah, R; Van Rossum, A; Vivien-Roels, B; Pévet, P
1998-09-01
In mammals, circadian rhythms generated by the suprachiasmatic nuclei (SCN) are daily synchronized by a light-dark cycle. Photic information is transmitted to the SCN mainly through the direct retinohypothalamic tract, the neurotransmitters involved being excitatory amino acids. It is also commonly accepted that photoperiodic information coming from the retina via the SCN is transduced by the pineal into a nocturnal signal, i.e. melatonin production. Light exposure at night induces (1) an inhibition of melatonin synthesis and (2) an expression of c-fos in numerous cells of SCN. To determine the role of the NMDA receptor in these effects, we treated Syrian hamsters with ip injections of MK-801, a noncompetitive NMDA receptor antagonist. Several subpopulations of light-sensitive cells in the SCN are affected by MK-801. According to previous studies, MK-801 inhibits light-induced Fos immunoreactivity mainly in the most ventral part of the SCN. However, we observed that numerous other cells are still activated by light. When light is applied in the middle of the night, MK-801 pretreatment does not reduce Fos-ir in the dorsal SCN. At the beginning of the night, labeled cells in this part of the nucleus appear even more numerous after MK-801. We also found that MK-801 fails to reduce the light-induced inhibition of melatonin synthesis. Moreover, in control animals, which received no light stimulation, ip injection of MK-801 induces by itself a dose-dependent inhibition of melatonin production.
NASA Astrophysics Data System (ADS)
Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Alekseev, I.; Aparin, A.; Arkhipkin, D.; Aschenauer, E. C.; Attri, A.; Averichev, G. S.; Bai, X.; Bairathi, V.; Bellwied, R.; Bhasin, A.; Bhati, A. K.; Bhattarai, P.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Bordyuzhin, I. G.; Bouchet, J.; Brandenburg, J. D.; Brandin, A. V.; Bunzarov, I.; Butterworth, J.; Caines, H.; Calderón de la Barca Sánchez, M.; Campbell, J. M.; Cebra, D.; Chakaberia, I.; Chaloupka, P.; Chang, Z.; Chatterjee, A.; Chattopadhyay, S.; Chen, J. H.; Chen, X.; Cheng, J.; Cherney, M.; Christie, W.; Contin, G.; Crawford, H. J.; Das, S.; De Silva, L. C.; Debbe, R. R.; Dedovich, T. G.; Deng, J.; Derevschikov, A. A.; di Ruzza, B.; Didenko, L.; Dilks, C.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Du, C. M.; Dunkelberger, L. E.; Dunlop, J. C.; Efimov, L. G.; Engelage, J.; Eppley, G.; Esha, R.; Evdokimov, O.; Eyser, O.; Fatemi, R.; Fazio, S.; Federic, P.; Fedorisin, J.; Feng, Z.; Filip, P.; Fisyak, Y.; Flores, C. E.; Fulek, L.; Gagliardi, C. A.; Garand, D.; Geurts, F.; Gibson, A.; Girard, M.; Greiner, L.; Grosnick, D.; Gunarathne, D. S.; Guo, Y.; Gupta, S.; Gupta, A.; Guryn, W.; Hamad, A. I.; Hamed, A.; Haque, R.; Harris, J. W.; He, L.; Heppelmann, S.; Heppelmann, S.; Hirsch, A.; Hoffmann, G. W.; Horvat, S.; Huang, T.; Huang, X.; Huang, B.; Huang, H. Z.; Huck, P.; Humanic, T. J.; Igo, G.; Jacobs, W. W.; Jang, H.; Jentsch, A.; Jia, J.; Jiang, K.; Judd, E. G.; Kabana, S.; Kalinkin, D.; Kang, K.; Kauder, K.; Ke, H. W.; Keane, D.; Kechechyan, A.; Khan, Z. H.; Kikoła, D. P.; Kisel, I.; Kisiel, A.; Kochenda, L.; Koetke, D. D.; Kosarzewski, L. K.; Kraishan, A. F.; Kravtsov, P.; Krueger, K.; Kumar, L.; Lamont, M. A. C.; Landgraf, J. M.; Landry, K. D.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, J. H.; Li, X.; Li, C.; Li, X.; Li, Y.; Li, W.; Lin, T.; Lisa, M. A.; Liu, F.; Ljubicic, T.; Llope, W. J.; Lomnitz, M.; Longacre, R. S.; Luo, X.; Ma, R.; Ma, G. L.; Ma, Y. G.; Ma, L.; Magdy, N.; Majka, R.; Manion, A.; Margetis, S.; Markert, C.; Matis, H. S.; McDonald, D.; McKinzie, S.; Meehan, K.; Mei, J. C.; Minaev, N. G.; Mioduszewski, S.; Mishra, D.; Mohanty, B.; Mondal, M. M.; Morozov, D. A.; Mustafa, M. K.; Nandi, B. K.; Nasim, Md.; Nayak, T. K.; Nigmatkulov, G.; Niida, T.; Nogach, L. V.; Noh, S. Y.; Novak, J.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Oh, K.; Okorokov, V. A.; Olvitt, D.; Page, B. S.; Pak, R.; Pan, Y. X.; Pandit, Y.; Panebratsev, Y.; Pawlik, B.; Pei, H.; Perkins, C.; Pile, P.; Pluta, J.; Poniatowska, K.; Porter, J.; Posik, M.; Poskanzer, A. M.; Pruthi, N. K.; Putschke, J.; Qiu, H.; Quintero, A.; Ramachandran, S.; Raniwala, R.; Raniwala, S.; Ray, R. L.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Ruan, L.; Rusnak, J.; Rusnakova, O.; Sahoo, N. R.; Sahu, P. K.; Sakrejda, I.; Salur, S.; Sandweiss, J.; Sarkar, A.; Schambach, J.; Scharenberg, R. P.; Schmah, A. M.; Schmidke, W. B.; Schmitz, N.; Seger, J.; Seyboth, P.; Shah, N.; Shahaliev, E.; Shanmuganathan, P. V.; Shao, M.; Sharma, M. K.; Sharma, B.; Shen, W. Q.; Shi, Z.; Shi, S. S.; Shou, Q. Y.; Sichtermann, E. P.; Sikora, R.; Simko, M.; Singha, S.; Skoby, M. J.; Smirnov, N.; Smirnov, D.; Solyst, W.; Song, L.; Sorensen, P.; Spinka, H. M.; Srivastava, B.; Stanislaus, T. D. S.; Stepanov, M.; Stock, R.; Strikhanov, M.; Stringfellow, B.; Sumbera, M.; Summa, B.; Sun, X. M.; Sun, Z.; Sun, Y.; Surrow, B.; Svirida, D. N.; Tang, Z.; Tang, A. H.; Tarnowsky, T.; Tawfik, A.; Thäder, J.; Thomas, J. H.; Timmins, A. R.; Tlusty, D.; Todoroki, T.; Tokarev, M.; Trentalange, S.; Tribble, R. E.; Tribedy, P.; Tripathy, S. K.; Tsai, O. D.; Ullrich, T.; Underwood, D. G.; Upsal, I.; Van Buren, G.; van Nieuwenhuizen, G.; Vandenbroucke, M.; Varma, R.; Vasiliev, A. N.; Vertesi, R.; Videbæk, F.; Vokal, S.; Voloshin, S. A.; Vossen, A.; Wang, Y.; Wang, G.; Wang, J. S.; Wang, H.; Wang, Y.; Wang, F.; Webb, G.; Webb, J. C.; Wen, L.; Westfall, G. D.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, Y.; Xiao, Z. G.; Xie, W.; Xie, G.; Xin, K.; Xu, H.; Xu, Z.; Xu, J.; Xu, Y. F.; Xu, Q. H.; Xu, N.; Yang, Y.; Yang, S.; Yang, C.; Yang, Y.; Yang, Y.; Yang, Q.; Ye, Z.; Ye, Z.; Yepes, P.; Yi, L.; Yip, K.; Yoo, I.-K.; Yu, N.; Zbroszczyk, H.; Zha, W.; Zhang, J.; Zhang, Y.; Zhang, X. P.; Zhang, Z.; Zhang, J. B.; Zhang, S.; Zhang, S.; Zhang, J.; Zhao, J.; Zhong, C.; Zhou, L.; Zhu, X.; Zoulkarneeva, Y.; Zyzak, M.; STAR Collaboration
2016-09-01
We present measurements of second-order azimuthal anisotropy (v2) at midrapidity (|y |<1.0 ) for light nuclei d ,t ,3He (for √{sN N}=200 , 62.4, 39, 27, 19.6, 11.5, and 7.7 GeV) and antinuclei d ¯ (√{sN N}=200 , 62.4, 39, 27, and 19.6 GeV) and ¯3He (√{sN N}=200 GeV) in the STAR (Solenoidal Tracker at RHIC) experiment. The v2 for these light nuclei produced in heavy-ion collisions is compared with those for p and p ¯. We observe mass ordering in nuclei v2(pT) at low transverse momenta (pT<2.0 GeV/c ). We also find a centrality dependence of v2 for d and d ¯. The magnitude of v2 for t and 3He agree within statistical errors. Light-nuclei v2 are compared with predictions from a blast-wave model. Atomic mass number (A ) scaling of light-nuclei v2(pT) seems to hold for pT/A <1.5 GeV /c . Results on light-nuclei v2 from a transport-plus-coalescence model are consistent with the experimental measurements.
Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; ...
2016-09-23
Here we present measurements of second-order azimuthal anisotropy ( v2 ) at midrapidity ( |y| < 1.0 ) for light nuclei d , t , 3He (formore » $$\\sqrt{s}$$$_{NN}$$ = 200 , 62.4, 39, 27, 19.6, 11.5, and 7.7 GeV) and antinuclei$$\\bar{d}$$ ( $$\\sqrt{s}$$$_{NN}$$ = 200 , 62.4, 39, 27, and 19.6 GeV) and 3 ¯¯¯¯¯ He ( $$\\sqrt{s}$$$_{NN}$$ = 200 GeV) in the STAR (Solenoidal Tracker at RHIC) experiment. The v2 for these light nuclei produced in heavy-ion collisions is compared with those for p and $$\\bar{p}$$. We observe mass ordering in nuclei v2 ( pT) at low transverse momenta ( pT < 2.0 GeV/c). We also find a centrality dependence of v2 for d and $$\\bar{d}$$ . The magnitude of v2 for t and 3He agree within statistical errors. Light-nuclei v2 are compared with predictions from a blast-wave model. Atomic mass number ( A ) scaling of light-nuclei v2 (pT) seems to hold for pT / A < 1.5 GeV/c . Results on light-nuclei v2 from a transport-plus-coalescence model are consistent with the experimental measurements.« less
Samsonenko, N.V.; Samgin, A.L.; Katkhat, C.L.
1988-02-01
We study the influence of meson-exchange currents of the second kind on the e-..nu.. angular correlation, on the coefficients of charge asymmetry, and on the degree of longitudinal polarization of electrons (positrons) in the ..beta../sup +- / decay of mirror light nuclei. The expressions for these characteristics obtained within the framework of the Kubodera-Delorme-Rho model are compared with the results of the impulse approximation. The mutual influence of the currents of the second kind and the neutrino mass is considered. The expected effects due to the influence of the Kubodera-Delorme-Rho parameters zeta and lambda are estimated.
Alt, E.O.; Irgaziev, B.F.; Muminov, A.T.
1995-11-01
The quasielastic breakup of light nuclei into two charged fragments in the Coulomb field of a heavy multiply charged ion are studied. For fragments diverging with extremely low energies an asymptotic estimate is obtained for the ratio of the differential cross section in which three-body Coulomb effects are taken into account to that in which these effects are disregarded. It is shown that effects due to the acceleration of breakup fragments in the field of the heavy ion are significant. 13 refs., 2 figs.
Ordering of the 0 d5 /2 and 1 s1 /2 proton levels in light nuclei
NASA Astrophysics Data System (ADS)
Hoffman, C. R.; Kay, B. P.; Schiffer, J. P.
2016-08-01
A survey of the available single-proton data in A ≤17 nuclei was completed. These data, along with calculations using a Woods-Saxon potential, show that the ordering of the 0 d5 /2 and 1 s1 /2 proton orbitals are determined primarily by the proximity of the s -state proton energy to the Coulomb barrier. This is analogous to the dependence of the corresponding neutron orbitals in proximity to the neutron threshold, which was previously discussed.
Fractal Dimension of Certain Continuous Functions of Unbounded Variation
NASA Astrophysics Data System (ADS)
Liang, Y. S.; Su, W. Y.
Continuous functions on closed intervals are composed of bounded variation functions and unbounded variation functions. Fractal dimension of continuous functions with bounded variation must be one-dimensional (1D). While fractal dimension of continuous functions with unbounded variation may be 1 or not. Certain continuous functions of unbounded variation whose fractal dimensions are 1 have been mainly investigated in the paper. A continuous function on a closed interval with finite unbounded variation points has been proved to be 1D. Furthermore, we deal with continuous functions which have infinite unbounded variation points and part of them have been proved to be 1D. Certain examples of 1D continuous functions which have uncountable unbounded variation points have been given in the present paper.
Analysis of unbounded operators and random motion
Jorgensen, Palle E. T.
2009-11-15
We study infinite weighted graphs with view to 'limits at infinity' or boundaries at infinity. Examples of such weighted graphs arise in infinite (in practice, that means 'very' large) networks of resistors or in statistical mechanics models for classical or quantum systems. However, more generally, our analysis includes reproducing kernel Hilbert spaces and associated operators on them. If X is some infinite set of vertices or nodes, in applications the essential ingredient going into the definition is a reproducing kernel Hilbert space; it measures the differences of functions on X evaluated on pairs of points in X. Moreover, the Hilbert norm-squared in H(X) will represent a suitable measure of energy. Associated unbounded operators will define a notion or dissipation, it can be a graph Laplacian or a more abstract unbounded Hermitian operator defined from the reproducing kernel Hilbert space under study. We prove that there are two closed subspaces in reproducing kernel Hilbert space H(X) that measure quantitative notions of limits at infinity in X: one generalizes finite-energy harmonic functions in H(X) and the other a deficiency index of a natural operator in H(X) associated directly with the diffusion. We establish these results in the abstract, and we offer examples and applications. Our results are related to, but different from, potential theoretic notions of 'boundaries' in more standard random walk models. Comparisons are made.
Morelli, L. D’Agostino, M.; Bruno, M.; Baiocco, G.; Gulminelli, F.; Cinausero, M.; Gramegna, F.; Marchi, T.; Degerlier, M.; Fabris, D.; Barlini, S.; Bini, M.; Casini, G.; Gelli, N.; Olmi, A.; Pasquali, G.; Piantelli, S.
2015-10-15
In the recent years, cluster structures have been evidenced in many ground and excited states of light nuclei [1, 2]. Within the currently ongoing experimental campaign by the NUCL-EX collaboration we have measured the {sup 12}C+{sup 12}C and {sup 14}N+{sup 10}B reactions at 95 MeV and 80 MeV respectively, and compared experimental data corresponding to complete fusion of target and projectile into an excited {sup 24}Mg nucleus to the results of a pure statistical model[3, 4]. We found clear deviations from the statstical model in the decay pattern: emission channels involving multiple α particles are more probable than expected from a purely statistical behavior. To continue the investigation on light systems, we have recentely measured the {sup 16}O+{sup 12}C reaction at three different beam energies, namely E{sub beam} = 90, 110 and 130 MeV.
Arifler, Dizem; MacAulay, Calum; Follen, Michele; Guillaud, Martial
2014-01-01
We use an extensive set of quantitative histopathology data to construct realistic three-dimensional models of normal and dysplastic cervical cell nuclei at different epithelial depths. We then employ the finite-difference time-domain method to numerically simulate the light scattering response of these representative models as a function of the polar and azimuthal scattering angles. The results indicate that intensity and shape metrics computed from two-dimensional scattering patterns can be used to distinguish between different diagnostic categories. Our numerical study also suggests that different epithelial layers and angular ranges need to be considered separately to fully exploit the diagnostic potential of two-dimensional light scattering measurements. PMID:24575343
Isospin Mixing and the Continuum Coupling in Weakly Bound Nuclei
Michel, N.; Nazarewicz, Witold; Ploszajczak, M.
2010-01-01
We investigate the near-threshold behavior of one-nucleon spectroscopic factors in mirror nuclei using the Gamow Shell Model, which simultaneously takes into account many-body correlations and continuum effects. We demonstrate that for weakly bound or unbound systems, the mirror symmetry-breaking effects are appreciable, and they manifest in large differences of spectroscopic factors in a mirror pair.
NASA Astrophysics Data System (ADS)
Nakamura, T.; Kondo, Y.
2016-06-01
Large acceptance spectrometers at in-flight RI separators have played significant roles in investigating the structure of exotic nuclei. Such spectrometers are in particular useful for probing unbound states of exotic nuclei, using invariant mass spectroscopy with reactions at intermediate and high energies. We discuss here the key characteristic features of such spectrometers, by introducing the recently commissioned SAMURAI facility at the RIBF, RIKEN. We also investigate the issue of cross talk in the detection of multiple neutrons, which has become crucial for exploring further unbound states and nuclei beyond the neutron drip line. Finally we discuss future perspectives for large acceptance spectrometers at the new-generation RI-beam facilities.
Emergent properties of nuclei from ab initio coupled-cluster calculations
Hagen, G.; Hjorth-Jensen, M.; Jansen, G. R.; Papenbrock, T.
2016-05-17
Emergent properties such as nuclear saturation and deformation, and the effects on shell structure due to the proximity of the scattering continuum and particle decay channels are fascinating phenomena in atomic nuclei. In recent years, ab initio approaches to nuclei have taken the first steps towards tackling the computational challenge of describing these phenomena from Hamiltonians with microscopic degrees of freedom. Our endeavor is now possible due to ideas from effective field theories, novel optimization strategies for nuclear interactions, ab initio methods exhibiting a soft scaling with mass number, and ever-increasing computational power. We review some of the recent accomplishments. We also present new results. The recently optimized chiral interaction NNLO${}_{{\\rm{sat}}}$ is shown to provide an accurate description of both charge radii and binding energies in selected light- and medium-mass nuclei up to 56Ni. We derive an efficient scheme for including continuum effects in coupled-cluster computations of nuclei based on chiral nucleon–nucleon and three-nucleon forces, and present new results for unbound states in the neutron-rich isotopes of oxygen and calcium. Finally, the coupling to the continuum impacts the energies of the ${J}^{\\pi }=1/{2}^{-},3/{2}^{-},7/{2}^{-},3/{2}^{+}$ states in ${}^{\\mathrm{17,23,25}}$O, and—contrary to naive shell-model expectations—the level ordering of the ${J}^{\\pi }=3/{2}^{+},5/{2}^{+},9/{2}^{+}$ states in ${}^{\\mathrm{53,55,61}}$Ca.
Emergent properties of nuclei from ab initio coupled-cluster calculations
Hagen, G.; Hjorth-Jensen, M.; Jansen, G. R.; Papenbrock, T.
2016-05-17
Emergent properties such as nuclear saturation and deformation, and the effects on shell structure due to the proximity of the scattering continuum and particle decay channels are fascinating phenomena in atomic nuclei. In recent years, ab initio approaches to nuclei have taken the first steps towards tackling the computational challenge of describing these phenomena from Hamiltonians with microscopic degrees of freedom. Our endeavor is now possible due to ideas from effective field theories, novel optimization strategies for nuclear interactions, ab initio methods exhibiting a soft scaling with mass number, and ever-increasing computational power. We review some of the recent accomplishments. We also present new results. The recently optimized chiral interaction NNLO${}_{{\\rm{sat}}}$ is shown to provide an accurate description of both charge radii and binding energies in selected light- and medium-mass nuclei up to 56Ni. We derive an efficient scheme for including continuum effects in coupled-cluster computations of nuclei based on chiral nucleon–nucleon and three-nucleon forces, and present new results for unbound states in the neutron-rich isotopes of oxygen and calcium. Finally, the coupling to the continuum impacts the energies of the ${J}^{\\pi }=1/{2}^{-},3/{2}^{-},7/{2}^{-},3/{2}^{+}$ states in ${}^{\\mathrm{17,23,25}}$O, and—contrary to naive shell-model expectations—the level ordering of the ${J}^{\\pi }=3/{2}^{+},5/{2}^{+},9/{2}^{+}$ states in ${}^{\\mathrm{53,55,61}}$Ca.
Emergent properties of nuclei from ab initio coupled-cluster calculations
NASA Astrophysics Data System (ADS)
Hagen, G.; Hjorth-Jensen, M.; Jansen, G. R.; Papenbrock, T.
2016-06-01
Emergent properties such as nuclear saturation and deformation, and the effects on shell structure due to the proximity of the scattering continuum and particle decay channels are fascinating phenomena in atomic nuclei. In recent years, ab initio approaches to nuclei have taken the first steps towards tackling the computational challenge of describing these phenomena from Hamiltonians with microscopic degrees of freedom. This endeavor is now possible due to ideas from effective field theories, novel optimization strategies for nuclear interactions, ab initio methods exhibiting a soft scaling with mass number, and ever-increasing computational power. This paper reviews some of the recent accomplishments. We also present new results. The recently optimized chiral interaction NNLO{}{{sat}} is shown to provide an accurate description of both charge radii and binding energies in selected light- and medium-mass nuclei up to 56Ni. We derive an efficient scheme for including continuum effects in coupled-cluster computations of nuclei based on chiral nucleon-nucleon and three-nucleon forces, and present new results for unbound states in the neutron-rich isotopes of oxygen and calcium. The coupling to the continuum impacts the energies of the {J}π =1/{2}-,3/{2}-,7/{2}-,3/{2}+ states in {}{17,23,25}O, and—contrary to naive shell-model expectations—the level ordering of the {J}π =3/{2}+,5/{2}+,9/{2}+ states in {}{53,55,61}Ca. ).
Bound and unbound nuclear systems at the drip lines: a one-dimensional model
NASA Astrophysics Data System (ADS)
Moschini, L.; Pérez-Bernal, F.; Vitturi, A.
2016-08-01
We construct a one-dimensional toy model to describe the main features of Borromean nuclei at the continuum threshold. The model consists of a core and two valence neutrons, unbound in the mean potential, that are bound by a residual point contact density-dependent interaction. Different discretization procedures are used (harmonic oscillator and transformed harmonic oscillator bases, or use of large rigid wall box). Resulting energies and wave functions, as well as inelastic transition intensities, are compared within the different discretization techniques, as well as with the exact results in the case of one particle and with the results of the di-neutron cluster model in the two particles case. Despite its simplicity, this model includes the main physical features of the structure of Borromean nuclei in an intuitive and computationally affordable framework, and will be extended to direct reaction calculations.
Spectroscopic studies of neutron-deficient light nuclei: decay properties of 21Mg, 25Si and 26P
NASA Astrophysics Data System (ADS)
Thomas, J.-C.; Achouri, L.; ńystö, J.; Béraud, R.; Blank, B.; Canchel, G.; Czajkowski, S.; Dendooven, P.; Ensallem, A.; Giovinazzo, J.; Guillet, N.; Honkanen, J.; Jokinen, A.; Laird, A.; Lewitowicz, M.; Longour, C.; de Oliveira Santos, F.; Stanoiu, M.
2003-09-01
Neutron-deficient nuclei with Tz equals to -3/2 and -2 have been produced at the GANIL/LISE3 facility in fragmentation reactions of a 95 MeV/u 36Ar primary beam in a 12C target. For the first time, β-delayed proton and β-γ emission has been simultaneously observed in the decay of 21Mg, 25Si and 26P. The decay scheme of the latter is proposed and the Gamow-Teller strength distribution in its β decay is compared to shell-model calculations based on the USD interaction. The B(GT) values derived from the absolute measurement of the β-branching ratios are in agreement with the quenching factor of about 60% obtained for allowed Gamow-Teller transitions in this mass region. A precise half-life of 43.7 (6) ms was determined for 26P, the β-2p emission of which was studied. The expected contribution of spectroscopic studies of neutron-rich nuclei is discussed with respect to the mirror asymmetry phenomenon occuring in analogous β decays.
Halo nuclei, stepping stones across the drip-lines
NASA Astrophysics Data System (ADS)
Simon, H.
2013-01-01
The availability of intense secondary beams in conjunction with modern efficient detection setups allows for the production and detailed study of the most extreme nuclear systems, in terms of asymmetry of proton and neutron number, in the continuum. Nuclei close to the drip-lines, exhibiting exotic properties themselves, can be used as a basis in order to populate these even more exotic nuclear systems, e.g. in transfer and knockout reactions. The latter challenge nuclear structure theory by being open quantum systems far from the valley of beta stability as well as reaction aiming at a description of their production mechanisms. Experiments provide data on momentum distributions, while relative energy spectra, and spin alignment during the reaction can be extracted and lead to the observation of energy and angular correlations as well as to dependent quantities such as, e.g., the profile function denoting a momentum width as a function of relative energy. They are determined from reaction products and gamma radiation emerging from the reaction zone. The link to intrinsic properties of these unbound systems has to be explored by gathering precise knowledge of the properties of the seed nuclei and compare them to structures observed in the continuum. In this paper, examples of the above-mentioned methods are presented. The current knowledge about light systems such as 5,7H, 7-10He, 10-13Li and the most neutron-rich oxygen systems is reviewed.
Rough differential equations with unbounded drift term
NASA Astrophysics Data System (ADS)
Riedel, S.; Scheutzow, M.
2017-01-01
We study controlled differential equations driven by a rough path (in the sense of T. Lyons) with an additional, possibly unbounded drift term. We show that the equation induces a solution flow if the drift grows at most linearly. Furthermore, we show that the semiflow exists assuming only appropriate one-sided growth conditions. We provide bounds for both the flow and the semiflow. Applied to stochastic analysis, our results imply strong completeness and the existence of a stochastic (semi)flow for a large class of stochastic differential equations. If the driving process is Gaussian, we can further deduce (essentially) sharp tail estimates for the (semi)flow and a Freidlin-Wentzell-type large deviation result.
A meshless method for unbounded acoustic problems.
Shojaei, Arman; Boroomand, Bijan; Soleimanifar, Ehsan
2016-05-01
In this paper an effective meshless method is proposed to solve time-harmonic acoustic problems defined on unbounded domains. To this end, the near field is discretized by a set of nodes and the far field effect is taken into account by considering radiative boundary conditions. The approximation within the near field is performed using a set of local residual-free basis functions defined on a series of finite clouds. For considering the far field effect, a series of infinite clouds are defined on which another set of residual-free bases, satisfying the radiation conditions, are considered for the approximation. Validation of the results is performed through solving some acoustic problems.
Evidence for Symplectic Symmetry in AbInitio No-Core Shell Model Results for Light Nuclei
NASA Astrophysics Data System (ADS)
Dytrych, Tomáš; Sviratcheva, Kristina D.; Bahri, Chairul; Draayer, Jerry P.; Vary, James P.
2007-04-01
Clear evidence for symplectic symmetry in low-lying states of C12 and O16 is reported. Eigenstates of C12 and O16, determined within the framework of the no-core shell model using the J-matrix inverse scattering potential with A≤16 (JISP16) nucleon-nucleon (NN) realistic interaction, typically project at the 85% 90% level onto a few of the most deformed symplectic basis states that span only a small fraction of the full model space. The results are nearly independent of whether the bare or renormalized effective interactions are used in the analysis. The outcome confirms Elliott’s SU(3) model which underpins the symplectic scheme, and above all, points to the relevance of a symplectic no-core shell model that can reproduce experimental B(E2) values without effective charges as well as deformed spatial modes associated with clustering phenomena in nuclei.
NASA Astrophysics Data System (ADS)
Erlykin, A. D.; Wolfendale, A. W.
2016-10-01
Evidence for a local ‘single source’ of cosmic rays is amassing by way of the recent precise measurements of various cosmic ray energy spectra from the AMS-02 instrument. To observations of individual cosmic ray nuclei, electrons, positrons and antiprotons must now be added the determination of the boron-to-carbon ratio and the energy spectrum of lithium to 2000 GV with high precision. Our analysis leads us to claim that, with certain assumptions about propagation in the Galaxy, the results confirm our arguments regarding the presence of a local single source, perhaps, a supernova remnant (SNR). An attempt is made to determine some of the properties of this SNR and its progenitor star.
Unbound free fatty acid profiles in human plasma and the unexpected absence of unbound palmitoleate.
Huber, Andrew H; Kleinfeld, Alan M
2017-03-01
We determined for the first time the profiles of the nine most abundant unbound FFAs (FFAus) in human plasma. Profiles were determined for a standard reference plasma of pooled healthy adults for which the Lipid MAPSMAPS Consortium had determined the total FFA profiles. Measurements were performed by using 20 different acrylodan-labeled fatty acid binding protein mutants (probes), which have complementary specificities for the nine FFAs that comprise more than 96% of long-chain plasma FFA. The acrylodan fluorescence emission for each probe changes upon binding a FFAu. The plasma concentrations of each of the nine FFAus were determined by combining the measured fluorescence ratios of the 20 probes. The total molar FFAu concentration accounted for <10(-5) of the total FFA concentration, and the mole fractions of the FFAu profiles were substantially different than the total FFA profiles. Myristic acid, for example, comprises 22% of the unbound versus 2.8% of the total. The most surprising difference is our finding of zero unbound cis-9-palmitoleic acid (POA), whereas the total POA was 7.2%. An unidentified plasma component appears to specifically prevent the release of POA. FFAus are the physiologically active FFAs, and plasma FFAu profiles may provide novel information about human health. Copyright © 2017 by the American Society for Biochemistry and Molecular Biology, Inc.
Borowska, L.; Terenetsky, K.; Verbitsky, V.; Fritzsche, S.
2007-09-15
The elastic scattering of light halo nuclei in the field of heavy targets has been studied for collision energies below the Coulomb barrier. Based on the assumption that the neutron halo follows the projectile adiabatically along its classical trajectory, a dynamic polarization potential is derived which describes both the (electrical) polarization as well as the breakup of the projectile in the field of the target. Detailed computations have been carried out for the elastic scattering of {sup 6}He+{sup 209}Bi at energies between 14.7 MeV and 19.1 MeV near to the Coulomb barrier. It is demonstrated that the polarization of the halo nucleus leads to a clear decrease of the (elastic) scattering cross section in excellent agreement with a recent measurement by Aguilera et al. [Phys. Rev. Lett. 84, 5058 (2000)].
G4MoNA - A Geant4 Simulation for unbound nuclides detected with MoNA/LISA
NASA Astrophysics Data System (ADS)
Gueye, Paul; Freeman, Jessica; Frank, Nathan; MoNA Collaboration
2017-01-01
The MoNA Collaboration has conducted a plethora of experiments to study unbound nuclei near the neutron dripline using the invariant mass technique since 2005. These experiments used a variety of secondary beams from the Coupled Cyclotron Facility of the National Superconducting Cyclotron Laboratory. The experimental setup consists of a large gap superconducting Sweeper magnet for charged fragments separation and the MoNA/LISA neutron detector arrays for neutron detection. Recently, a multi-layered Si/Be segmented target consisting of three 700 mg/cm2 thick 9Be slabs and four 140 μ m Si detectors were added to the setup. This target improves the resolution of the reconstructed decay energy spectra of the unbound nuclides. The Geant4 Monte Carlo simulation toolkit was used to develop a complete realistic model of the setup including a new class to treat the decay of unbound nuclei, the Si/Be segmented target, the MoNA/LISA and the charged fragments detector systems. Comparison between simulated and experimental data will be presented. DoENNSA - DE-NA0000979.
Dobb, Rachel; Martial, Franck; Elijah, Daniel; Storchi, Riccardo; Brown, Timothy M; Lucas, Robert J
2017-09-05
Electrophysiological responses of SCN neurons to light steps are well established, but responses to more natural modulations in irradiance have been much less studied. We address this deficit first by showing that variations in irradiance for human subjects are biased towards low temporal frequencies and small magnitudes. Using extracellular recordings we show that neurons in the mouse SCN are responsive to stimuli with these characteristics, tracking sinusoidal modulations in irradiance best at lower temporal frequencies and responding to abrupt changes in irradiance over a range of commonly encountered contrasts. The spectral sensitivity of these light adapted responses indicates that they are driven primarily by cones, but with melanopsin (and/or rods) contributing under more gradual changes. Higher frequency modulations in irradiance increased time averaged firing of SCN neurons (typically considered to encode background light intensity) modestly over that encountered during steady exposure, but did not have a detectable effect on the circadian phase resetting efficiency of light. Our findings highlight the SCN's ability to encode naturalistic temporal modulations in irradiance, while revealing that the circadian system can effectively integrate such signals over time such that phase-resetting responses remain proportional to the mean light exposure.
NASA Astrophysics Data System (ADS)
Ciemała, M.; Kmiecik, M.; Maj, A.; Mazurek, K.; Bracco, A.; Kravchuk, V. L.; Casini, G.; Barlini, S.; Baiocco, G.; Bardelli, L.; Bednarczyk, P.; Benzoni, G.; Bini, M.; Blasi, N.; Brambilla, S.; Bruno, M.; Camera, F.; Carboni, S.; Cinausero, M.; Chbihi, A.; Chiari, M.; Corsi, A.; Crespi, F. C. L.; D'Agostino, M.; Degerlier, M.; Fornal, B.; Giaz, A.; Gramegna, F.; Krzysiek, M.; Leoni, S.; Marchi, T.; Matejska-Minda, M.; Mazumdar, I.; Meczyński, W.; Million, B.; Montanari, D.; Morelli, L.; Myalski, S.; Nannini, A.; Nicolini, R.; Pasquali, G.; Piantelli, S.; Prete, G.; Roberts, O. J.; Schmitt, Ch.; Styczeń, J.; Szpak, B.; Valdré, S.; Wasilewska, B.; Wieland, O.; Wieleczko, J. P.; Ziebliński, M.; Dudek, J.; Dinh Dang, N.
2015-05-01
High-energy giant dipole resonance (GDR) γ rays were measured following the decay of the hot, rotating compound nucleus of 88Mo, produced at excitation energies of 124 and 261 MeV. The reaction 48Ti + 40Ca at 300 and 600 MeV bombarding energies has been used. The data were analyzed using the statistical model Monte Carlo code gemini++. It allowed extracting the giant dipole resonance parameters by fitting the high-energy γ -ray spectra. The extracted GDR widths were compared with the available data at lower excitation energy and with theoretical predictions based on (i) The Lublin-Strasbourg drop macroscopic model, supplemented with thermal shape fluctuations analysis, and (ii) The phonon damping model. The theoretical predictions were convoluted with the population matrices of evaporated nuclei from the statistical model gemini++. Also a comparison with the results of a phenomenological expression based on the existing systematics, mainly for lower temperature data, is presented and discussed. A possible onset of a saturation of the GDR width was observed around T =3 MeV.
Sundaralingam, Nakamuthu
1993-06-08
We study multiple muon events (muon bundles) recorded underground at a depth of 2090 mwe. To penetrate to this depth, the muons must have energies above 0.8 TeV at the Earth`s surface; the primary cosmic ray nuclei which give rise to the observed muon bundles have energies at incidence upon the upper atmosphere of 10 to 10^{5}TeV. The events are detected using the Soudan 2 experiment`s fine grained tracking calorimeter which is surrounded by a 14 m x 10 m x 31 m proportional tube array (the ``active shield``). Muon bundles which have at least one muon traversing the calorimeter, are reconstructed using tracks in the calorimeter together with hit patterns in the proportional tube shield. All ionization pulses are required to be coincident within 3 microseconds. A goal of this study is to investigate the relative nuclear abundances in the primary cosmic radiation around the ``knee`` region (10^{3} - 10^{4} TeV) of the incident energy spectrum. Four models for the nuclear composition of cosmic rays are considered: The Linsley model, the Constant Mass Composition model (CMC), the Maryland model and the Proton-poor model. A Monte Carlo which incorporates one model at a time is used to simulate events which are then reconstructed using the same computer algorithms that are used for the data. Identical cuts and selections are applied to the data and to the simulated events.
Litvinova, E. V.; Afanasjev, A. V.
2011-07-15
The impact of particle-vibration coupling and polarization effects due to deformation and time-odd mean fields on single-particle spectra is studied systematically in doubly magic nuclei from low-mass {sup 56}Ni up to superheavy ones. Particle-vibration coupling is treated fully self-consistently within the framework of the relativistic particle-vibration coupling model. Polarization effects due to deformation and time-odd mean field induced by odd particle are computed within covariant density functional theory. It has been found that among these contributions the coupling to vibrations makes a major impact on the single-particle structure. The impact of particle-vibration coupling and polarization effects on calculated single-particle spectra, the size of the shell gaps, the spin-orbit splittings and the energy splittings in pseudospin doublets is discussed in detail; these physical observables are compared with experiment. Particle-vibration coupling has to be taken into account when model calculations are compared with experiment since this coupling is responsible for observed fragmentation of experimental levels; experimental spectroscopic factors are reasonably well described in model calculations.
NASA Astrophysics Data System (ADS)
Bertsch, G. F.
Gerry Brown initiated some early studies on the coexistence of different nuclear shapes. The subject has continued to be of interest and is crucial for understanding nuclear fission. We now have a very good picture of the potential energy surface with respect to shape degrees of freedom in heavy nuclei, but the dynamics remain problematic. In contrast, the early studies on light nuclei were quite successful in describing the mixing between shapes. Perhaps a new approach in the spirit of the old calculations could better elucidate the character of the fission dynamics and explain phenomena that current theory does not model well.
NASA Astrophysics Data System (ADS)
Holt, Roy J.
2016-03-01
Electron scattering at very high Bjorken x from hadrons provides an excellent test of models, has an important role in high energy physics, and from nuclei, provides a window into short range correlations. Light nuclei have a key role because of the relatively well-known nuclear structure. The development of a novel tritium target for Jefferson Lab has led to renewed interest in the mass three system. For example, deep inelastic scattering experiments in the light nuclei provide a powerful means to determine the neutron structure function. The isospin dependence of electron scattering from mass-3 nuclei provide information on short range correlations in nuclei. The program using the new tritium target will be presented along with a summary of other experiments aimed at revealing the large-x structure of the nucleon.
Spectral similarity of unbound asteroid pairs
NASA Astrophysics Data System (ADS)
Wolters, Stephen D.; Weissman, Paul R.; Christou, Apostolis; Duddy, Samuel R.; Lowry, Stephen C.
2014-04-01
Infrared (IR) spectroscopy between 0.8 and 2.5 μ has been obtained for both components of three unbound asteroid pairs, using the NASA Infrared Telescope Facility with the SpeX instrument. Pair primary (2110) Moore-Sitterly is classified as an S-type following the Bus-DeMeo taxonomy; the classification for secondary (44612) 1999 RP27 is ambiguous: S/Sq/Q/K/L-type. Primary (10484) Hecht and secondary (44645) 1999 RC118 are classified as V-types. IR spectra for Moore-Sitterly and Hecht are each linked with available visual photometry. The classifications for primary (88604) 2001 QH293 and (60546) 2000 EE85 are ambiguous: S/Sq/Q/K/L-type. Subtle spectral differences between them suggest that the primary may have more weathered material on its surface. Dynamical integrations have constrained the ages of formation: 2110-44612 > 782 kyr; 10484-44645 = 348 (+823,-225) kyr; 88604-60546 = 925 (+842,-754) kyr. The spectral similarity of seven complete pairs is ranked in comparison with nearby background asteroids. Two pairs, 17198-229056 and 19289-278067, have significantly different spectra between the components, compared to the similarity of spectra in the background population. The other pairs are closer than typical, supporting an interpretation of each pair's formation from a common parent body.
Tong, C G; Reichler, S; Blumenthal, S; Balk, J; Hsieh, H L; Roux, S J
1997-01-01
A cDNA encoding a nucleolar protein was selected from a pea (Pisum sativum) plumule library, cloned, and sequenced. The translated sequence of the cDNA has significant percent identity to Xenopus laevis nucleolin (31%), the alfalfa (Medicago sativa) nucleolin homolog (66%), and the yeast (Saccharomyces cerevisiae) nucleolin homolog (NSR1) (28%). It also has sequence patterns in its primary structure that are characteristic of all nucleolins, including an N-terminal acidic motif, RNA recognition motifs, and a C-terminal Gly- and Arg-rich domain. By immunoblot analysis, the polyclonal antibodies used to select the cDNA bind selectively to a 90-kD protein in purified pea nuclei and nucleoli and to an 88-kD protein in extracts of Escherichia coli expressing the cDNA. In immunolocalization assays of pea plumule cells, the antibodies stained primarily a region surrounding the fibrillar center of nucleoli, where animal nucleolins are typically found. Southern analysis indicated that the pea nucleolin-like protein is encoded by a single gene, and northern analysis showed that the labeled cDNA binds to a single band of RNA, approximately the same size and the cDNA. After irradiation of etiolated pea seedlings by red light, the mRNA level in plumules decreased during the 1st hour and then increased to a peak of six times the 0-h level at 12 h. Far-red light reversed this effect of red light, and the mRNA accumulation from red/far-red light irradiation was equal to that found in the dark control. This indicates that phytochrome may regulate the expression of this gene. PMID:9193096
Extension of the Liège intranuclear-cascade model to reactions induced by light nuclei
NASA Astrophysics Data System (ADS)
Mancusi, Davide; Boudard, Alain; Cugnon, Joseph; David, Jean-Christophe; Kaitaniemi, Pekka; Leray, Sylvie
2014-11-01
The purpose of this paper is twofold. First, we present the extension of the Liège intranuclear-cascade model to reactions induced by light ions. We describe here the ideas upon which we built our treatment of nucleus-nucleus reactions and we compare the model predictions against a vast set of heterogeneous experimental data. In spite of the discussed limitations of the intranuclear-cascade scheme, we find that our model yields valid predictions for a number of observables and positions itself as one of the most attractive alternatives available to geant4 users for the simulation of light-ion-induced reactions. Second, we describe the c++ version of the code, which is physicswise equivalent to the legacy version, is available in geant4, and will serve as the basis for all future development of the model.
Mente, Scot; Doran, Angela; Wager, Travis T
2012-06-14
The objective of this work was to establish that unbound maximum concentrations may be reasonably predicted from a combination of computed molecular properties assuming subcutaneous (SQ) dosing. Additionally, we show that the maximum unbound plasma and brain concentrations may be projected from a mixture of in vitro absorption, distribution, metabolism, excretion experimental parameters in combination with computed properties (volume of distribution, fraction unbound in microsomes). Finally, we demonstrate the utility of the underlying equations by showing that the maximum total plasma concentrations can be projected from the experimental parameters for a set of compounds with data collected from clinical research.
Gagarskii, A. M.; Guseva, I. S.; Goennenwein, F.; Kopach, Yu. N.; Mutterer, M.; Kuz'mina, T. E.; Petrov, G. A.; Tyurin, G.; Nesvizhevsky, V.
2011-12-15
The new physical effects of T-odd asymmetry of the emission of light charged particles (LCPs) during the ternary fission of some heavy nuclei by cold polarized neutrons have been experimentally studied. The coefficients of triple scalar and vector correlation of the pulses of light particles and fission fragments (TRI effect) and the fivefold correlation of the same vectors (ROT effect) have been measured. These effects are believed to be caused by the rotation of polarized fissioning system around its polarization direction. The treatment of the experimental data for LCPs in the framework of this hypothesis leads to a good agreement between the calculation results and experimental data. The calculated value of the angle of rotation of the fission axis in the ternary fission of the polarized fissioning {sup 236}U* compound nucleus was used to process the results of measuring the ROT effect for {gamma} photons from binary-fission fragments of the same nucleus. A satisfactory description of these experimental data is obtained which serves a convincing confirmation of the rotation hypothesis.
Janssens, R.V.F.; Khoo, Teng Lek.
1991-01-01
This paper reviews the most recent advances in the understanding of the physics of superdeformed nuclei from the point of view of the experimentalists. It covers among other subjects the following topics: (1) the discovery of a new region of superdeformed nuclei near A=190, (2) the surprising result of the occurrence of bands with identical transition energies in neighboring superdeformed nuclei near A=150 and A=190, (3) the importance of octupole degrees of freedom at large deformation and (4) the properties associated with the feeding and the decay of superdeformed bands. The text presented hereafter will appear as a contribution to the Annual Review of Nuclear and Particle Science, Volume 41. 88 refs., 11 figs.
Akram, W.; Schönbächler, M.; Sprung, P.; Vogel, N.
2013-11-10
Recent work based on analyses of meteorite and terrestrial whole-rock samples showed that the r- and s- process isotopes of Hf were homogeneously distributed throughout the inner solar system. We report new Hf isotope data for Calcium-Aluminum-rich inclusions (CAIs) of the CV3 carbonaceous chondrite Allende, and novel high-precision Zr isotope data for these CAIs and three carbonaceous chondrites (CM, CO, CK). Our Zr data reveal enrichments in the neutron-rich isotope {sup 96}Zr (≤1ε in {sup 96}Zr/{sup 90}Zr) for bulk chondrites and CAIs (∼2ε). Potential isotope effects due to incomplete sample dissolution, galactic and cosmic ray spallation, and the nuclear field shift are assessed and excluded, leading to the conclusion that the {sup 96}Zr isotope variations are of nucleosynthetic origin. The {sup 96}Zr enrichments are coupled with {sup 50}Ti excesses suggesting that both nuclides were produced in the same astrophysical environment. The same CAIs also exhibit deficits in r-process Hf isotopes, which provides strong evidence for a decoupling between the nucleosynthetic processes that produce the light (A ≤ 130) and heavy (A > 130) neutron-rich isotopes. We propose that the light neutron-capture isotopes largely formed in Type II supernovae (SNeII) with higher mass progenitors than the supernovae that produced the heavy r-process isotopes. In the context of our model, the light isotopes (e.g. {sup 96}Zr) are predominantly synthesized via charged-particle reactions in a high entropy wind environment, in which Hf isotopes are not produced. Collectively, our data indicates that CAIs sampled an excess of materials produced in a normal mass (12-25 M{sub ☉}) SNII.
NASA Astrophysics Data System (ADS)
Elshoukrofy, A. Sh. M.; Postnikov, E. B.; Korosteleva, E. E.; Sveshnikova, L. G.; Motaweh, H. A.
2017-06-01
In this paper we propose a `knee-like' approximation of the lateral distribution of the Cherenkov light from extensive air showers in the energy range 30-3000 TeV and study a possibility of its practical application in high energy ground-based gamma-ray astronomy experiments (in particular, in TAIGA-HiSCORE). The approximation has a very good accuracy for individual showers and can be easily simplified for practical application in the HiSCORE wide angle timing array in the condition of a limited number of triggered stations.
Unbound (bioavailable) IGF1 enhances somatic growth
Elis, Sebastien; Wu, Yingjie; Courtland, Hayden-William; Cannata, Dara; Sun, Hui; Beth-On, Mordechay; Liu, Chengyu; Jasper, Hector; Domené, Horacio; Karabatas, Liliana; Guida, Clara; Basta-Pljakic, Jelena; Cardoso, Luis; Rosen, Clifford J.; Frystyk, Jan; Yakar, Shoshana
2011-01-01
SUMMARY Understanding insulin-like growth factor-1 (IGF1) biology is of particular importance because, apart from its role in mediating growth, it plays key roles in cellular transformation, organ regeneration, immune function, development of the musculoskeletal system and aging. IGF1 bioactivity is modulated by its binding to IGF-binding proteins (IGFBPs) and the acid labile subunit (ALS), which are present in serum and tissues. To determine whether IGF1 binding to IGFBPs is necessary to facilitate normal growth and development, we used a gene-targeting approach and generated two novel knock-in mouse models of mutated IGF1, in which the native Igf1 gene was replaced by Des-Igf1 (KID mice) or R3-Igf1 (KIR mice). The KID and KIR mutant proteins have reduced affinity for the IGFBPs, and therefore present as unbound IGF1, or ‘free IGF1’. We found that both KID and KIR mice have reduced serum IGF1 levels and a concomitant increase in serum growth hormone levels. Ternary complex formation of IGF1 with the IGFBPs and the ALS was markedly reduced in sera from KID and KIR mice compared with wild type. Both mutant mice showed increased body weight, body and bone lengths, and relative lean mass. We found selective organomegaly of the spleen, kidneys and uterus, enhanced mammary gland complexity, and increased skeletal acquisition. The KID and KIR models show unequivocally that IGF1-complex formation with the IGFBPs is fundamental for establishing normal body and organ size, and that uncontrolled IGF bioactivity could lead to pathological conditions. PMID:21628395
NASA Technical Reports Server (NTRS)
Raisbeck, G. M.
1986-01-01
Cosmogenic nuclei, nuclides formed by nuclear interactions of galactic and solar cosmic rays with extraterrestrial or terrestrial matter are discussed. Long lived radioactive cosmogenic isotopes are focused upon. Their uses in dating, as tracers of the interactions of cosmic rays with matter, and in obtaining information on the variation of primary cosmic ray flux in the past are discussed.
NASA Astrophysics Data System (ADS)
Goyal, Arti; Mhaskey, Mukul; Gopal-Krishna; Wiita, Paul J.; Stalin, C. S.; Sagar, Ram
2013-09-01
It is important to quantify the underestimation of rms photometric errors returned by the commonly used APPHOT algorithm in the IRAF software, in the context of differential photometry of point-like AGN, because of the crucial role it plays in evaluating their variability properties. Published values of the underestimation factor, η, using several different telescopes, lie in the range 1.3-1.75. The present study aims to revisit this question by employing an exceptionally large data set of 262 differential light curves (DLCs) derived from 262 pairs of non-varying stars monitored under our ARIES AGN monitoring program for characterizing the intra-night optical variability (INOV) of prominent AGN classes. The bulk of these data were taken with the 1-m Sampurnanad Telescope (ST). We find η = 1.54±0.05 which is close to our recently reported value of η = 1.5. Moreover, this consistency holds at least up to a brightness mismatch of 1.5 mag between the paired stars. From this we infer that a magnitude difference of at least up to 1.5 mag between a point-like AGN and comparison star(s) monitored simultaneously is within the same CCD chip acceptable, as it should not lead to spurious claims of INOV.
Sub-Barrier Fusion with Exotic Nuclei
NASA Astrophysics Data System (ADS)
Alamanos, N.; Auger, F.; Keeley, N.; Lapoux, V.; Rusek, K.; Pakou, A.
2005-09-01
Interest in the mechanism of near- and sub-barrier fusion has been renewed, with the advent of radioactive beam facilities, due to the specific properties of unbound and weakly bound beams, such as extended neutron densities, low-lying continuum, and very low energy break-up thresholds. It is expected that these properties will appreciably affect fusion, as well as other reaction channels like breakup. We discuss the role played by these properties in barrier and sub-barrier fusion of weakly bound and unstable nuclei. The data are compared to calculations performed within the coupled channels and continuum discretized coupled channels schemes.
NASA Astrophysics Data System (ADS)
Vesna, V. A.; Gledenov, Yu. M.; Nesvizhevsky, V. V.; Petukhov, A. K.; Sedyshev, P. V.; Soldner, T.; Shulgina, E. V.
2009-08-01
We present two measurements of parity-violating secondary particle emission asymmetry in the reactions of polarized cold neutrons and light nuclei. We aim at studies of the neutral weak currents in nucleon-nucleon interaction. First, we describe the triton emission asymmetry in the Li6(n,α)H3 reaction. It is equal to αP-odd6=-(8.8±2.1)ṡ10. Second, we present the γ-rays emission asymmetry in the nuclear reaction B10(n,α)Li∗7→γ→Li7(g.s.). The result is αP-odd10=+(0.8±3.9)ṡ10. Using these values, we constrain the weak neutral current constant in framework of the cluster model fπ6⩽1.1ṡ10 and fπ10⩽2.4ṡ10 (at 90% c.i.). Both these constrains contradict to “the best” DDH value of fπDDH=4.6ṡ10.
NASA Astrophysics Data System (ADS)
Kunieda, Satoshi
2017-09-01
We report the status of the R-matrix code AMUR toward consistent cross-section evaluation and covariance analysis for the light-mass nuclei. The applicable limit of the code is extended by including computational capability for the charged-particle elastic scattering cross-sections and the neutron capture cross-sections as example results are shown in the main texts. A simultaneous analysis is performed on the 17O compound system including the 16O(n,tot) and 13C(α,n)16O reactions together with the 16O(n,n) and 13C(α,α) scattering cross-sections. It is found that a large theoretical background is required for each reaction process to obtain a simultaneous fit with all the experimental cross-sections we analyzed. Also, the hard-sphere radii should be assumed to be different from the channel radii. Although these are technical approaches, we could learn roles and sources of the theoretical background in the standard R-matrix.
Babut, Richard; Bouland, Olivier; Fort, Eric
2005-10-15
Evaluated data are adjusted on experimental measurements using nuclear reaction models. Among these data, those concerning alpha-particle interactions on light nuclei are not well known, although crucial for neutron emission problems via ({alpha},n) processes in nuclear fuels (oxide, carbide, nitride). Examples of applications are reprocessing, packaging and storage of radioactive waste, and intrinsic neutron source term evaluation in critical and subcritical reactors (accelerator-driven systems). The goal is the modeling of ({alpha},n) reactions on oxygen isotopes to extract the resonance parameters. The SAMMY code, which relies on the Reich-Moore approximation of the R-matrix theory, is used. In the most recent version, the SAMMY code allows the study of the in- and outgoing charged-particle channels. An important validation of this new feature has been made. In addition, a manifest lack of experimental data for this type of reaction has been underlined. Finally, the impact of the new pointwise description of the ({alpha},n) reaction cross section on the energy distribution calculation of the intrinsic neutron source of an irradiated mixed-oxide fuel pin is shown and compared to the standard calculation, which uses average cross sections.
Pantic, Igor; Pantic, Senka; Basta-Jovanovic, Gordana
2012-06-01
In our study we investigated the relationship between conventional morphometric indicators of nuclear size and shape (area and circularity) and the parameters of gray level co-occurrence matrix texture analysis (entropy, homogeneity, and angular second moment) in cells committed to apoptosis. A total of 432 lymphocyte nuclei images from the spleen germinal center light zones (cells in early stages of apoptosis) were obtained from eight healthy male guinea pigs previously immunized with sheep red blood cells (antigen). For each nucleus, area, circularity, entropy, homogeneity, and angular second moment were determined. All measured parameters of gray level co-occurrence matrix (GLCM) were significantly correlated with morphometric indicators of nuclear size and shape. The strongest correlation was observed between GLCM homogeneity and nuclear area (p < 0.0001, r(s) = 0.61). Angular second moment values were also highly significantly correlated with nuclear area (r(s)= 0.39, p < 0.0001). These results indicate that the GLCM method may be a powerful tool in evaluation of ultrastructural nuclear changes during early stages of the apoptotic process.
NASA Astrophysics Data System (ADS)
Khoa, Dao Tien; Egelhof, Peter; Gales, Sydney; Giai, Nguyen Van; Motobayashi, Tohru
2008-04-01
. -- Thermal pairing in nuclei / N. D. Dang -- Molecular-orbital and di-nuclei states in Ne and F isotopes / M. Kimura -- Low-momentum interactions for nuclei / A. Schwenk -- Nonrelativistic nuclear energy functionals including the tensor force / G. Colo et al. -- New aspects on dynamics in nuclei described by covariant density functional theory / P. Ring, D. Pena -- Theoretical studies on ground-state properties of superheavy nuclei / Z. Z. Ren et al. -- New results in the study of superfluid nuclei: many-body effects, spectroscopic factors / P. F. Bortignon et al. -- New Effective nucleon-nucleon interaction for the mean-field approximation / V. K. Au et al. -- Linear response calculations with the time-dependent Skyrme density functional / T. Nakatsukasa et al. -- Dissipative dynamics with exotic beams / M. Di Toro et al. -- Exploring the symmetry energy of asymmetric nuclear matter with heavy ion reactions / M. B. Tsang -- Invariant mass spectroscopy of halo nuclei / T. Nakamura et al. -- Core [symbol] structures in [symbol]C, [symbol]C and [symbol]C up to high excitation energies / H. G. Bohlen et al. -- Light neutron-rich nuclei studied by alpha-induced reactions / S. Shimoura -- Fusion and direct reactions around the Coulomb barrier for the system [symbol]He + [symbol]Zn / V. Scuderi et al. -- Analyzing power measurement for proton elastic scattering on [symbol]He / S. Sakaguchi et al. -- Knockout reaction spectroscopy of exotic nuclei / J. A. Tostevin -- Exotic nuclei, quantum phase transitions, and the evolution of structure / R. F. Casten -- Structure of exotic nuclei in the medium mass region / T. Otsuka -- Pairing correlations in halo nuclei / H. Sagawa, K. Hagino -- Experimental approach to high-temperature Stellar reactions with low-energy RI beams / S. Kubono et al. -- Transition to quark matter in neutron stars / G. X. Peng et al. -- Research at VATLY: main themes and recent results / P. N. Diep et al. -- Study of the astrophysical reaction [symbol
MMT HYPERVELOCITY STAR SURVEY. II. FIVE NEW UNBOUND STARS
Brown, Warren R.; Geller, Margaret J.; Kenyon, Scott J. E-mail: mgeller@cfa.harvard.edu
2012-05-20
We present the discovery of five new unbound hypervelocity stars (HVSs) in the outer Milky Way halo. Using a conservative estimate of Galactic escape velocity, our targeted spectroscopic survey has now identified 16 unbound HVSs as well as a comparable number of HVSs ejected on bound trajectories. A Galactic center origin for the HVSs is supported by their unbound velocities, the observed number of unbound stars, their stellar nature, their ejection time distribution, and their Galactic latitude and longitude distribution. Other proposed origins for the unbound HVSs, such as runaway ejections from the disk or dwarf galaxy tidal debris, cannot be reconciled with the observations. An intriguing result is the spatial anisotropy of HVSs on the sky, which possibly reflects an anisotropic potential in the central 10-100 pc region of the Galaxy. Further progress requires measurement of the spatial distribution of HVSs over the southern sky. Our survey also identifies seven B supergiants associated with known star-forming galaxies; the absence of B supergiants elsewhere in the survey implies there are no new star-forming galaxies in our survey footprint to a depth of 1-2 Mpc.
Galindo-Uribarri, Alfredo {nmn}
2010-01-01
Current experimental developments on the study of exotic nuclei far from the valley of stability are discussed. I start with general aspects related to the production of radioactive beams followed by the description of some of the experimental tools and specialized techniques for studies in reaction spectroscopy, nuclear structure research and nuclear applications with examples from selected topical areas with which I have been involved. I discuss some of the common challenges faced in Accelerator Mass Spectrometry (AMS) and Radioactive Ion Beam (RIB) science.
Stochastic homogenization of a front propagation problem with unbounded velocity
NASA Astrophysics Data System (ADS)
Hajej, A.
2017-04-01
We study the homogenization of Hamilton-Jacobi equations which arise in front propagation problems in stationary ergodic media. Our results are obtained for fronts moving with possible unbounded velocity. We show, by an example, that the homogenized Hamiltonian, which always exists, may be unbounded. In this context, we show convergence results if we start with a compact initial front. On the other hand, if the media satisfies a finite range of dependence condition, we prove that the effective Hamiltonian is bounded and obtain classical homogenization in this context.
Verifying Multi-Agent Systems via Unbounded Model Checking
NASA Technical Reports Server (NTRS)
Kacprzak, M.; Lomuscio, A.; Lasica, T.; Penczek, W.; Szreter, M.
2004-01-01
We present an approach to the problem of verification of epistemic properties in multi-agent systems by means of symbolic model checking. In particular, it is shown how to extend the technique of unbounded model checking from a purely temporal setting to a temporal-epistemic one. In order to achieve this, we base our discussion on interpreted systems semantics, a popular semantics used in multi-agent systems literature. We give details of the technique and show how it can be applied to the well known train, gate and controller problem. Keywords: model checking, unbounded model checking, multi-agent systems
NASA Astrophysics Data System (ADS)
Subramanian, R.; Kok, G. L.; Baumgardner, D.; Twohy, C.
2008-12-01
The single particle soot photometer (SP2) measures strongly-light absorbing (black) carbon (LAC) using laser incandescence. During the Ice in Clouds Experiment (ICE-L) conducted over Colorado and Wyoming in November/December 2007, the SP2 was operated downstream of a counterflow virtual impactor (CVI) onboard the NCAR C-130 aircraft, when the plane passed through a cloud. The CVI collects cloud droplets and ice crystals larger than 8 μm and evaporates the water content, so that residual nuclei are sampled. The CVI also concentrates the incoming air-stream by as much as a factor of 30 or more. The combination enables measurements of LAC much lower than 1 ng/m3. Results indicate that compared to aerosol in the surrounding air mass, LAC concentrations (per unit volume air) were generally lower in cloud. On November 16, two wave clouds were sampled near Riverton and Wheatland, WY at altitudes between 6-8 km above sea level. LAC mass concentrations upwind of the clouds averaged 5.6 and 4 ng/m3, while in- cloud averages were 0.6 and 0.3 ng/m3 respectively. Average number scavenging ratios of LAC- containing particles measured by the SP2 were 17% and 14% for the two mixed liquid/ice cloud events. In- cloud LAC mass normalized to cloud water content (CWC) was 19 ng/g-CWC in the Riverton cloud, and lower over Wheaton. Multiple passes at different altitudes through the cloud nearer Wheaton did not show a dependence of LAC/CWC on altitude. In a wave cloud over the Wind River Range on November 29, ice-only portions showed LAC/CWC about a factor-of-4 lower than smaller mixed-phase regions of the cloud. Data on LAC measurements in upslope conditions will also be presented.
Neutron properties from light nuclei
NASA Astrophysics Data System (ADS)
Epelbaum, Evgeny; Hammer, Hans-Werner; Meißner, Ulf-G.
2017-01-01
We review the achievements of the project B.6. Topics addressed include pion photoproduction of three-nucleon systems, electromagnetic and axial currents in chiral nuclear EFT, aspects of EFTs with spin-3/2 fields, nuclear structure and dynamics from the pionless EFT, the development and applications of high-precision two-nucleon forces and pion production in nucleon-nucleon collisions.
Nuclei and Fundamental Symmetries
NASA Astrophysics Data System (ADS)
Haxton, Wick
2016-09-01
Nuclei provide marvelous laboratories for testing fundamental interactions, often enhancing weak processes through accidental degeneracies among states, and providing selection rules that can be exploited to isolate selected interactions. I will give an overview of current work, including the use of parity violation to probe unknown aspects of the hadronic weak interaction; nuclear electric dipole moment searches that may shed light on new sources of CP violation; and tests of lepton number violation made possible by the fact that many nuclei can only decay by rare second-order weak interactions. I will point to opportunities in both theory and experiment to advance the field. Based upon work supported in part by the US Department of Energy, Office of Science, Office of Nuclear Physics and SciDAC under Awards DE-SC00046548 (Berkeley), DE-AC02-05CH11231 (LBNL), and KB0301052 (LBNL).
Emergent properties of nuclei from ab initio coupled-cluster calculations
Hagen, G.; Hjorth-Jensen, M.; Jansen, G. R.; ...
2016-05-17
Emergent properties such as nuclear saturation and deformation, and the effects on shell structure due to the proximity of the scattering continuum and particle decay channels are fascinating phenomena in atomic nuclei. In recent years, ab initio approaches to nuclei have taken the first steps towards tackling the computational challenge of describing these phenomena from Hamiltonians with microscopic degrees of freedom. Our endeavor is now possible due to ideas from effective field theories, novel optimization strategies for nuclear interactions, ab initio methods exhibiting a soft scaling with mass number, and ever-increasing computational power. We review some of the recent accomplishments. We also present new results. The recently optimized chiral interaction NNLOmore » $${}_{{\\rm{sat}}}$$ is shown to provide an accurate description of both charge radii and binding energies in selected light- and medium-mass nuclei up to 56Ni. We derive an efficient scheme for including continuum effects in coupled-cluster computations of nuclei based on chiral nucleon–nucleon and three-nucleon forces, and present new results for unbound states in the neutron-rich isotopes of oxygen and calcium. Finally, the coupling to the continuum impacts the energies of the $${J}^{\\pi }=1/{2}^{-},3/{2}^{-},7/{2}^{-},3/{2}^{+}$$ states in $${}^{\\mathrm{17,23,25}}$$O, and—contrary to naive shell-model expectations—the level ordering of the $${J}^{\\pi }=3/{2}^{+},5/{2}^{+},9/{2}^{+}$$ states in $${}^{\\mathrm{53,55,61}}$$Ca.« less
2015-01-01
Background Characterizing the interface residues will help shed light on protein-protein interactions, which are involved in many important biological processes. Many studies focus on characterizing sequence or structure features of protein interfaces, but there are few studies characterizing the dynamics of interfaces. Therefore, we would like to know whether there is any specific dynamics pattern in the protein-protein interaction interfaces. Thermal fluctuation is an important dynamical property for a residue, and could be quickly estimated by local packing density without large computation since studies have showen closely relationship between these two properties. Therefore, we divided surface of an unbound subunit (free protein subunits before they are involved in forming the protein complexes) into several separate regions, and compared their average thermal fluctuations of different regions in order to characterize the dynamics pattern in unbound protein-protein interaction interfaces. Results We used weighted contact numbers (WCN), a parameter-free method to quantify packing density, to estimate the thermal fluctuations of residues in the interfaces. By analyzing the WCN distributions of interfaces in unbound subunits from 1394 non-homologous protein complexes, we show that the residues in the central regions of interfaces have higher packing density (i.e. more rigid); on the other hand, residues surrounding the central regions have smaller packing density (i.e. more flexible). The distinct distributions of packing density, suggesting distinct thermal fluctuation, reveals specific dynamics pattern in the interface of unbound protein subunits. Conclusions We found general trend that the unbound protein-protein interaction interfaces consist of rigid residues in the central regions, which are surrounded by flexible residues. This finding suggests that the dynamics might be one of the important features for the formation of protein complexes. PMID:25708145
Yang, Xuezhi; Wang, Qi; Qu, Xiaolei; Jiang, Wei
2017-02-12
Natural organic matter influences the carbon nanotube transport in aqueous environments. The role of bound humic acid (HA) on carbon nanotubes and unbound HA in bulk solution in the aggregation and deposition of carboxylated multi-walled carbon nanotubes (C-MWNTs) was examined in NaCl and CaCl2 electrolyte solution. Time-resolved dynamic light scattering and quartz crystal microbalance with dissipation monitoring were employed to investigate the C-MWNT aggregation and deposition kinetics, respectively. The critical coagulation concentration (CCC) of C-MWNTs is 30mM in NaCl and 3mM in CaCl2. The bound HA results in CCCs of 32mM in NaCl and 2.9mM in CaCl2. However, the existing unbound HA causes much slower aggregation in both NaCl and CaCl2 electrolytes and results in CCCs of 86mM in NaCl and 5.8mM in CaCl2. The HA adsorption experiment confirms the additional adsorption of unbound HA in the presence of cations, which can increase the steric effect between C-MWNTs. The more negative charge of C-MWNTs in the presence of unbound HA also stabilizes the suspension. In contrast, the bound HA on C-MWNTs has a more remarkable effect on the deposition rate on the SiO2 surface than the unbound HA. Bound HA changes the C-MWNT surface functional groups, leading to differences in the interaction between C-MWNTs and the SiO2 surface. Hence, the C-MWNTs dispersed by their covalently bonded oxygen-containing groups on the carbon framework and dispersed by the bound HA show nearly the same aggregation rates but quite different deposition rates. The additional unbound HA adsorption does not change the surface functional groups or the changing trend of the CNT deposition rate. Distinguishing the role of bound and unbound HA in the aggregation and deposition of carbon nanomaterials is important to predict their transport in various natural waters.
A Unified Framework for Bounded and Unbounded Numerical Estimation
ERIC Educational Resources Information Center
Kim, Dan; Opfer, John E.
2017-01-01
Representations of numerical value have been assessed by using bounded (e.g., 0-1,000) and unbounded (e.g., 0-?) number-line tasks, with considerable debate regarding whether 1 or both tasks elicit unique cognitive strategies (e.g., addition or subtraction) and require unique cognitive models. To test this, we examined how well a mixed log-linear…
Strong stabilisation and decay estimate for unbounded bilinear systems
NASA Astrophysics Data System (ADS)
El Ayadi, R.; Ouzahra, M.; Boutoulout, A.
2012-10-01
In this article, we deal with distributed bilinear systems, where the operator of control is supposed to be unbounded in the sense that it is bounded from the state space into some extension. Then we give sufficient conditions for strong stabilisation. Also the rate of convergence of the state is estimated. An illustrating example is given.
Automated Circulation of Unbound Periodicals: A Survey of Practices.
ERIC Educational Resources Information Center
Tracy, Joan
1983-01-01
Presents results of survey of procedures to handle the circulation of unbound periodicals in 232 public and academic libraries using four major turnkey automated circulation systems. Methods used are described (use of machine-readable symbol attached to issue) and procedures developed at the Eastern Washington University Library are explained in…
"University Unbound" Rebounds: Can MOOCs "Educate" as Well as Train?
ERIC Educational Resources Information Center
McCully, George
2012-01-01
In the days since NEBHE convened hundreds of educators and opinion leaders in Boston for the "University Unbound" conference, people have received a surge of reactions including the one from George McCully, founder of the "Catalogue for Philanthropy." NEBHE has begun focusing the attention of New England institutions on the…
Electroproduction of Strange Nuclei
E.V. Hungerford
2002-06-01
The advent of high-energy, CW-beams of electrons now allows electro-production and precision studies of nuclei containing hyperons. Previously, the injection of strangeness into a nucleus was accomplished using secondary beams of mesons, where beam quality and target thickness limited the missing mass resolution. We review here the theoretical description of the (e, e'K+) reaction mechanism, and discuss the first experiment demonstrating that this reaction can be used to precisely study the spectra of light hypernuclei. Future experiments based on similar techniques, are expected to attain even better resolutions and rates.
Towards the exact calculation of medium nuclei
Gandolfi, Stefano; Carlson, Joseph Allen; Lonardoni, Diego; Wang, Xiaobao
2016-12-19
The prediction of the structure of light and medium nuclei is crucial to test our knowledge of nuclear interactions. The calculation of the nuclei from two- and three-nucleon interactions obtained from rst principle is, however, one of the most challenging problems for many-body nuclear physics.
International Symposium on Exotic Nuclei
NASA Astrophysics Data System (ADS)
Penionzhkevich, Yu. E.; Cherepanov, E. A.
Methods of production of light exotic nuclei and study of their ptoperties -- Superheavy elements. Syhnthesis and properties -- Nuclear fission -- Nuclear reactions -- rare processes, decay and nuclear structure -- Experimental set-ups and future projects -- Radioactive beams. Production and research programmes -- Public relations.
Chiral electroweak currents in nuclei
Riska, D. O.; Schiavilla, R.
2017-01-10
Here, the development of the chiral dynamics based description of nuclear electroweak currents is reviewed. Gerald E. (Gerry) Brown’s role in basing theoretical nuclear physics on chiral Lagrangians is emphasized. Illustrative examples of the successful description of electroweak observables of light nuclei obtained from chiral effective field theory are presented.
Octupole correlation effects in nuclei
Chasman, R.R.
1992-01-01
Octupole correlation effects in nuclei are discussed from the point of view of many-body wavefunctions as well as mean-field methods. The light actinides, where octupole effects are largest, are considered in detail. Comparisons of theory and experiment are made for energy splittings of parity doublets; E1 transition matrix elements and one-nucleon transfer reactions.
Octupole correlation effects in nuclei
Chasman, R.R.
1992-08-01
Octupole correlation effects in nuclei are discussed from the point of view of many-body wavefunctions as well as mean-field methods. The light actinides, where octupole effects are largest, are considered in detail. Comparisons of theory and experiment are made for energy splittings of parity doublets; E1 transition matrix elements and one-nucleon transfer reactions.
The Fastest Unbound Stars in the Universe
NASA Astrophysics Data System (ADS)
Guillochon, James; Loeb, Abraham
2015-06-01
The discovery of hypervelocity stars (HVSs) leaving our galaxy with speeds of nearly 103 km s-1 has provided strong evidence of the existence of a massive compact object at the galaxy’s center. HVSs ejected via the disruption of stellar binaries can occasionally yield a star with {{v}∞ } ≲ {{10}4} km s-1 here we show that this mechanism can be extended to massive black hole (MBH) mergers, where the secondary star is replaced by a MBH with mass {{M}2}≳ {{10}5}{{M}⊙ }. We find that stars that are originally bound to the secondary MBH are frequently ejected with {{v}∞ }\\gt {{10}4} km s-1, and occasionally with velocities ˜105 km s-1 (one third the speed of light). For this reason we refer to stars ejected from these systems as “semi-relativistic” hypervelocity stars (SHSs). Bound to no galaxy, the velocities of these stars are so great that they can cross a significant fraction of the observable universe in the time since their ejection (several Gpc). We demonstrate that if a significant fraction of MBH mergers undergoes a phase in which their orbital eccentricity is ≳0.5 and their periapse distance is tens of the primary’s Schwarzschild radius, the space density of fast-moving ({{v}∞ }\\gt {{10}4} km s-1) SHSs may be as large as 103 Mpc-3. Hundreds of SHSs will be giant stars that can be detected by future all-sky infrared surveys such as WFIRST or Euclid and proper motion surveys such as LSST, with spectroscopic follow-up being possible with the James Webb Space Telescope.
When Is It Important to Measure Unbound Drug in Evaluating Nanomedicine Pharmacokinetics?
Stern, Stephan T; Martinez, Marilyn N; Stevens, David M
2016-12-01
Nanoformulations have become important tools for modifying drug disposition, be it from the perspective of enabling prolonged drug release, protecting the drug molecule from metabolism, or achieving targeted delivery. When examining the in vivo pharmacokinetic properties of these formulations, most investigations either focus on systemic concentrations of total (encapsulated plus unencapsulated) drug, or concentrations of encapsulated and unencapsulated drug. However, it is rare to find studies that differentiate between protein-bound and unbound (free) forms of the unencapsulated drug. In light of the unique attributes of these formulations, we cannot simply assume it appropriate to rely upon the protein-binding properties of the traditionally formulated or legacy drug when trying to define the pharmacokinetic or pharmacokinetic/pharmacodynamic characteristics of these nanoformulations. Therefore, this commentary explores reasons why it is important to consider not only unencapsulated drug, but also the portion of unencapsulated drug that is not bound to plasma proteins. Specifically, we highlight those situations when it may be necessary to include measurement of unencapsulated, unbound drug concentrations as part of the nanoformulation pharmacokinetic evaluation.
Spinor fields with zero mass in unbounded isotropic media
Hillion, P.
1988-01-01
The Dirac equation for massless fields in unbounded media has solutions similar to the focus wave mode solutions of Maxwell's equations leading to infinite dynamical invariants. We define the splash wave mode solutions as a weighted superposition of the focus wave modes, and discuss the conditions to be fulfilled by the weight functions to make the dynamical invariants bounded. We leave open the physical interpretation of these solutions.
Unbound States of the Drip-Line Nucleus 24O
NASA Astrophysics Data System (ADS)
Lapoux, V.; Boissinot, S.; Pollacco, E. C.; Flavigny, F.; Louchart, C.; Nalpas, L.; Obertelli, A.; Otsu, H.; Baba, H.; Chen, R. J.; Fukuda, N.; Inabe, N.; Kameda, D.; Matsushita, M.; Motobayashi, T.; Onishi, T.; Nikolskii, E. Y.; Nishimura, M.; Sakurai, H.; Takechi, M.; Takeuchi, S.; Togano, Y.; Yoneda, K.; Yoshida, A.; Yoshida, K.; Matta, A.; Blumenfeld, Y.; Franchoo, S.; Hammache, F.; Rosier, Ph.; Rindel, E.; Gangnant, P.; Houarner, Ch.; Libin, J. F.; Saillant, F.
2013-09-01
The characteristics of the new N = 16 shell gap at the neutron drip-line can be deduced from the neutron excitations of 24O. An experiment was carried out to investigate the unbound excited states of 24O using the proton elastic and inelastic proton scattering. It was performed in the BigRIPS line and combines the unique intensities of the RIBF 24O beam with the state-of-the-art particle detector array MUST2. The method is explained.
Asymptotic stability of nonlinear systems with unbounded delays
NASA Astrophysics Data System (ADS)
Tan, Man-Chun
2008-01-01
Some asymptotic stability criteria are derived for systems of nonlinear functional differential equations with unbounded delays. The criteria are described as matrix equations or matrix inequalities, which are computationally flexible and efficient. The theories are then applied to the stabilization of time-delay systems via standard feedback control (SFC) or time-delayed feedback control (DFC). Several examples are given to illustrate the results.
Stabilization of linear distributed control systems with unbounded delay
NASA Astrophysics Data System (ADS)
Henríquez, Hernán R.; Hernández M., Eduardo
2005-07-01
In this paper we study the asymptotic stabilization of linear distributed parameter control systems with unbounded delay. Assuming that the semigroup of operators associated with the uncontrolled and nondelayed equation is compact and that the phase space is a uniform fading memory space, we characterize those systems that can be stabilized using a feedback control. As consequence we conclude that every system of this type is stabilizable with an appropriated finite dimensional control.
Unbounded dynamics in dissipative flows: Rössler model.
Barrio, Roberto; Blesa, Fernando; Serrano, Sergio
2014-06-01
Transient chaos and unbounded dynamics are two outstanding phenomena that dominate in chaotic systems with large regions of positive and negative divergences. Here, we investigate the mechanism that leads the unbounded dynamics to be the dominant behavior in a dissipative flow. We describe in detail the particular case of boundary crisis related to the generation of unbounded dynamics. The mechanism of the creation of this crisis in flows is related to the existence of an unstable focus-node (or a saddle-focus) equilibrium point and the crossing of a chaotic invariant set of the system with the weak-(un)stable manifold of the equilibrium point. This behavior is illustrated in the well-known Rössler model. The numerical analysis of the system combines different techniques as chaos indicators, the numerical computation of the bounded regions, and bifurcation analysis. For large values of the parameters, the system is studied by means of Fenichel's theory, providing formulas for computing the slow manifold which influences the evolution of the first stages of the orbit.
Unbounded dynamics in dissipative flows: Rössler model
Barrio, Roberto Serrano, Sergio; Blesa, Fernando
2014-06-15
Transient chaos and unbounded dynamics are two outstanding phenomena that dominate in chaotic systems with large regions of positive and negative divergences. Here, we investigate the mechanism that leads the unbounded dynamics to be the dominant behavior in a dissipative flow. We describe in detail the particular case of boundary crisis related to the generation of unbounded dynamics. The mechanism of the creation of this crisis in flows is related to the existence of an unstable focus-node (or a saddle-focus) equilibrium point and the crossing of a chaotic invariant set of the system with the weak-(un)stable manifold of the equilibrium point. This behavior is illustrated in the well-known Rössler model. The numerical analysis of the system combines different techniques as chaos indicators, the numerical computation of the bounded regions, and bifurcation analysis. For large values of the parameters, the system is studied by means of Fenichel's theory, providing formulas for computing the slow manifold which influences the evolution of the first stages of the orbit.
Unbounded dynamics in dissipative flows: Rössler model
Barrio, Roberto Serrano, Sergio; Blesa, Fernando
2014-06-15
Transient chaos and unbounded dynamics are two outstanding phenomena that dominate in chaotic systems with large regions of positive and negative divergences. Here, we investigate the mechanism that leads the unbounded dynamics to be the dominant behavior in a dissipative flow. We describe in detail the particular case of boundary crisis related to the generation of unbounded dynamics. The mechanism of the creation of this crisis in flows is related to the existence of an unstable focus-node (or a saddle-focus) equilibrium point and the crossing of a chaotic invariant set of the system with the weak-(un)stable manifold of the equilibrium point. This behavior is illustrated in the well-known Rössler model. The numerical analysis of the system combines different techniques as chaos indicators, the numerical computation of the bounded regions, and bifurcation analysis. For large values of the parameters, the system is studied by means of Fenichel's theory, providing formulas for computing the slow manifold which influences the evolution of the first stages of the orbit.
Zonal structure of unbounded external-flow and aerodynamics
NASA Astrophysics Data System (ADS)
Liu, L. Q.; Kang, L. L.; Wu, J. Z.
2017-08-01
This paper starts from the far-field behaviors of velocity field in externally unbounded flow. We find that the well-known algebraic decay of disturbance velocity as derived kinematically is too conservative. Once the kinetics are taken into account by working on the fundamental solutions of far-field linearized Navier-Stokes equations, it is proven that the furthest far-field zone adjacent to the uniform fluid at infinity must be unsteady, viscous and compressible, where all disturbances degenerate to sound waves that decay exponentially. But this optimal rate does not exist in some commonly used simplified flow models, such as steady flow, incompressible flow and inviscid flow, because they actually work in true subspaces of the unbounded free space, which are surrounded by further far fields of different nature. This finding naturally leads to a zonal structure of externally unbounded flow field. The significance of the zonal structure is demonstrated by its close relevance to existing theories of aerodynamic force and moment in external flows, including the removal of the difficulties or paradoxes inherent in the simplified models.
Stochastic Homogenization of Nonconvex Unbounded Integral Functionals with Convex Growth
NASA Astrophysics Data System (ADS)
Duerinckx, Mitia; Gloria, Antoine
2016-09-01
We consider the well-trodden ground of the problem of the homogenization of random integral functionals. When the integrand has standard growth conditions, the qualitative theory is well-understood. When it comes to unbounded functionals, that is, when the domain of the integrand is not the whole space and may depend on the space-variable, there is no satisfactory theory. In this contribution we develop a complete qualitative stochastic homogenization theory for nonconvex unbounded functionals with convex growth. We first prove that if the integrand is convex and has p-growth from below (with p > d, the dimension), then it admits homogenization regardless of growth conditions from above. This result, that crucially relies on the existence and sublinearity at infinity of correctors, is also new in the periodic case. In the case of nonconvex integrands, we prove that a similar homogenization result holds provided that the nonconvex integrand admits a two-sided estimate by a convex integrand (the domain of which may depend on the space variable) that itself admits homogenization. This result is of interest to the rigorous derivation of rubber elasticity from polymer physics, which involves the stochastic homogenization of such unbounded functionals.
Kurisaki, Ikuo; Takayanagi, Masayoshi; Nagaoka, Masataka
2015-03-05
We shed light on important roles of unbound Na(+) molecules in enzymatic activation of thrombin. Molecular mechanism of Na(+)-activation of thrombin has been discussed in the context of allostery. However, the recent challenge to redesign K(+)-activated thrombin revealed that the allosteric interaction is insufficient to explain the mechanism. Under these circumstances, we have examined the roles of unbound Na(+) molecule in maximization of thrombin-substrate association reaction rate. We performed all-atomic molecular dynamics (MD) simulations of thrombin in the presence of three different cations; Li(+), Na(+), and Cs(+). Although these cations are commonly observed in the vicinity of the S1-pocket of thrombin, smaller cations are distributed more densely and extensively than larger ones. This suggests the two observation rules: (i) thrombin surrounded by Na(+) is at an advantage in the initial step of association reaction, namely, the formation of an encounter complex ensemble, and (ii) the presence of Na(+) molecules does not necessarily have an advantage in the final step of association reaction, namely, the formation of the stereospecific complex. In conclusion, we propose a conjecture that unbound Na(+) molecules also affect the maximization of rate constant of thrombin-substrate association reaction through optimally forming an encounter complex ensemble.
Coexistence of Covalent Superdeformation and Molecular Resonances in an Unbound Region of {sup 12}Be
Ito, M.; Sakurai, H.; Ikeda, K.; Itagaki, N.
2008-05-09
The generalized two-center cluster model, which can treat static structures and dynamical reactions in excited states, is applied to the light neutron-rich system, {sup 12}Be={alpha}+{alpha}+4N. We discuss the change of the neutrons' configuration around two {alpha} cores from the covalent structure to the ionic one. We show that, in the unbound region above particle-decay thresholds, the ionic configurations appear as the molecular resonances of {alpha}+{sup 8}He, {sup 6}He+{sup 6}He, and {sup 5}He+{sup 7}He. A new type of superdeformation is possible, and we find here a covalent superdeformation with a hybrid configuration of both the covalent and ionic structures. The excitation of these exotic structures through the two-neutron transfer reaction is also discussed.
Second 0+ state of unbound 12O: Scaling of mirror asymmetry
NASA Astrophysics Data System (ADS)
Suzuki, D.; Iwasaki, H.; Beaumel, D.; Assié, M.; Baba, H.; Blumenfeld, Y.; de Oliveira Santos, F.; de Séréville, N.; Drouart, A.; Franchoo, S.; Gibelin, J.; Gillibert, A.; Giron, S.; Grévy, S.; Guillot, J.; Hackstein, M.; Hammache, F.; Keeley, N.; Lapoux, V.; Maréchal, F.; Matta, A.; Michimasa, S.; Nalpas, L.; Naqvi, F.; Okamura, H.; Otsu, H.; Pancin, J.; Pang, D. Y.; Perrot, L.; Petrache, C. M.; Pollacco, E.; Ramus, A.; Rother, W.; Roussel-Chomaz, P.; Sakurai, H.; Scarpaci, J.-A.; Sorlin, O.; Srivastava, P. C.; Stefan, I.; Stodel, C.; Tanimura, Y.; Terashima, S.
2016-02-01
The unbound 12O nucleus was studied via the two-neutron transfer (p ,t ) reaction in inverse kinematics using a radioactive 14O beam at 51 MeV/u. Excitation energy spectra and differential cross sections were deduced by the missing mass method using MUST2 telescopes. We achieved much higher statistics compared to the previous experiments of 12O, which allowed accurate determination of resonance energy and unambiguous spin and parity assignment. The 12O resonance previously reported using the same reaction was confirmed at an excitation energy of 1.62 ±0.03 (stat . )±0.10 (syst . ) . MeV and assigned spin and parity of 0+ from a distorted-wave Born approximation analysis of the differential cross sections. Mirror symmetry of 12O with respect to its neutron-rich partner 12Be is discussed from the energy difference of the second 0+ states. In addition, from systematics of known 0+ states, a distinct correlation is revealed between the mirror energy difference and the binding energy after carrying out a scaling with the mass and the charge. We show that the mirror energy difference of the observed 0+ state of 12O is highly deviated from the systematic trend of deeply bound nuclei and in line with the scaling relation found for weakly bound nuclei with a substantial 2 s1 /2 component. The importance of the scaling of mirror asymmetry is discussed in the context of ab initio calculations near the drip lines and universality of few-body quantum systems.
Cavitation inception from bubble nuclei.
Mørch, K A
2015-10-06
The tensile strength of ordinary water such as tap water or seawater is typically well below 1 bar. It is governed by cavitation nuclei in the water, not by the tensile strength of the water itself, which is extremely high. Different models of the nuclei have been suggested over the years, and experimental investigations of bubbles and cavitation inception have been presented. These results suggest that cavitation nuclei in equilibrium are gaseous voids in the water, stabilized by a skin which allows diffusion balance between gas inside the void and gas in solution in the surrounding liquid. The cavitation nuclei may be free gas bubbles in the bulk of water, or interfacial gaseous voids located on the surface of particles in the water, or on bounding walls. The tensile strength of these nuclei depends not only on the water quality but also on the pressure-time history of the water. A recent model and associated experiments throw new light on the effects of transient pressures on the tensile strength of water, which may be notably reduced or increased by such pressure changes.
Cavitation inception from bubble nuclei
Mørch, K. A.
2015-01-01
The tensile strength of ordinary water such as tap water or seawater is typically well below 1 bar. It is governed by cavitation nuclei in the water, not by the tensile strength of the water itself, which is extremely high. Different models of the nuclei have been suggested over the years, and experimental investigations of bubbles and cavitation inception have been presented. These results suggest that cavitation nuclei in equilibrium are gaseous voids in the water, stabilized by a skin which allows diffusion balance between gas inside the void and gas in solution in the surrounding liquid. The cavitation nuclei may be free gas bubbles in the bulk of water, or interfacial gaseous voids located on the surface of particles in the water, or on bounding walls. The tensile strength of these nuclei depends not only on the water quality but also on the pressure–time history of the water. A recent model and associated experiments throw new light on the effects of transient pressures on the tensile strength of water, which may be notably reduced or increased by such pressure changes. PMID:26442138
NASA Astrophysics Data System (ADS)
Tain, J. L.; Guadilla, V.; Valencia, E.; Algora, A.; Zakari-Issoufou, A.-A.; Rice, S.; Meur, L. Le; Agramunt, J.; Äystö, J.; Batist, L.; Bowry, M.; Briz, J. A.; Bui, V. M.; Caballero-Folch, R.; Cano-Ott, D.; Cucoanes, A.; Elomaa, V.-V.; Eronen, T.; Estevez, E.; Estienne, M.; Fallot, M.; Farrelly, G. F.; Fraile, L. M.; Ganioglu, E.; Garcia, A. R.; Gelletly, W.; Gómez-Hornillos, B.; Gorelov, D.; Gorlychev, V.; Hakala, J.; Jokinen, A.; Jordan, M. D.; Kankainen, A.; Kolhinen, V. S.; Kondev, F. G.; Koponen, J.; Lebois, M.; Martínez, T.; Mason, P.; Mendoza, E.; Monserrate, M.; Montaner-Pizá, A.; Moore, I.; Nacher, E.; Orrigo, S. E. A.; Penttilä, H.; Podolyák, Zs.; Pohjalainen, I.; Porta, A.; Regan, P. H.; Reinikainen, J.; Reponen, M.; Rinta-Antila, S.; Rissanen, J.; Rubio, B.; Rytkönen, K.; Shiba, T.; Sonnenschein, V.; Sonzogni, A. A.; Vedia, V.; Voss, A.; Wilson, J. N.
2017-09-01
Total absorption gamma-ray spectroscopy is used to measure accurately the intensity of γ emission from neutron-unbound states populated in the β-decay of delayed-neutron emitters. From the comparison of this intensity with the intensity of neutron emission one can deduce information on the (n,γ) cross section for unstable neutron-rich nuclei of interest in r process abundance calculations. A surprisingly large γ branching was observed for a number of isotopes. The results are compared with Hauser-Feshbach calculations and discussed.
Tain, J. L.; Guadilla, V.; Valencia, E.; ...
2017-09-13
Total absorption gamma-ray spectroscopy is used to measure accurately the intensity of γ emission from neutron-unbound states populated in the β-decay of delayed-neutron emitters. From the comparison of this intensity with the intensity of neutron emission one can deduce information on the (n,γ) cross section for unstable neutron-rich nuclei of interest in r process abundance calculations. A surprisingly large γ branching was observed for a number of isotopes. Here, the results are compared with Hauser-Feshbach calculations and discussed.
Approximate Model Checking of PCTL Involving Unbounded Path Properties
NASA Astrophysics Data System (ADS)
Basu, Samik; Ghosh, Arka P.; He, Ru
We study the problem of applying statistical methods for approximate model checking of probabilistic systems against properties encoded as
NASA Technical Reports Server (NTRS)
Tan, L. C.
1985-01-01
The interstellar antiproton calculations were reexamined in view of the recent progress in measurements of interstellar electrons and He(3) nuclei. It was found that the divergence between the predicted antiproton flux and the existing datum at very low energies is increased. The proposed nonuniform galactic disk (NUGD) model qualitatively explains the unexpectedly large flux of interstellar antiprotons. Some ambiguities existed in the prototype of the model. It was unclear what fraction of observed antiprotons is of local origin. Previously the value of cosmic ray escape pathlength was suggested with quite a large arbitrariness.
The Ordering of the 0{ital d}{sub 5/2} and 1{ital s}{sub 1/2} Proton Levels in Light Nuclei
Hoffman, C. R.; Kay, B. P.; Schiffer, J. P.
2016-08-22
A survey of the available single-proton data in A ≤ 17 nuclei was completed. These data, along with calculations using a Woods-Saxon potential, show that the ordering of the 0d5/2 and 1s1/2 proton orbitals are determined primarily by the proximity of the s-state proton energy to the Coulomb barrier. This is analogous to the dependence of the corresponding neutron orbitals in proximity to the neutron threshold, that was previously discussed.
Selective population of unbound states in 10Li
NASA Astrophysics Data System (ADS)
Smith, J. K.; Baumann, T.; Brown, J.; DeYoung, P. A.; Frank, N.; Hinnefeld, J.; Kohley, Z.; Luther, B.; Marks, B.; Spyrou, A.; Stephenson, S. L.; Thoennessen, M.; Williams, S. J.
2015-08-01
Unbound positive-parity states in 10Li have been populated with a two-proton removal reaction from a 71 MeV/u 12B beam. The 9Li fragments and emitted neutrons were measured with the MoNA-LISA-Sweeper setup. The measured decay energy spectrum was best fit with three states at 110 ± 40, 500 ± 100, and 1100 ± 100 keV decay energy. This is the second observation of a resonance below 200 keV. The lower two states likely belong to the expected 1+, 2+ doublet.
Localized basis sets for unbound electrons in nanoelectronics.
Soriano, D; Jacob, D; Palacios, J J
2008-02-21
It is shown how unbound electron wave functions can be expanded in a suitably chosen localized basis sets for any desired range of energies. In particular, we focus on the use of Gaussian basis sets, commonly used in first-principles codes. The possible usefulness of these basis sets in a first-principles description of field emission or scanning tunneling microscopy at large bias is illustrated by studying a simpler related phenomenon: The lifetime of an electron in a H atom subjected to a strong electric field.
Erosive Hit-and-Run Impact Events: Debris Unbound
NASA Astrophysics Data System (ADS)
Sarid, Gal; Stewart, Sarah T.; Leinhardt, Zoë M.
2016-01-01
Erosive collisions among planetary embryos in the inner solar system can lead to multiple remnant bodies, varied in mass, composition and residual velocity. Some of the smaller, unbound debris may become available to seed the main asteroid belt. The makeup of these collisionally produced bodies is different from the canonical chondritic composition, in terms of rock/iron ratio and may contain further shock-processed material. Having some of the material in the asteroid belt owe its origin from collisions of larger planetary bodies may help in explaining some of the diversity and oddities in composition of different asteroid groups.
Dynamics of an unbounded interface between ordered phases.
Krapivsky, P L; Redner, S; Tailleur, J
2004-02-01
We investigate the evolution of a single unbounded interface between ordered phases in two-dimensional Ising ferromagnets that are endowed with single-spin-flip zero-temperature Glauber dynamics. We examine specifically the cases where the interface initially has either one or two corners. In both examples, the interface evolves to a limiting self-similar form. We apply the continuum time-dependent Ginzburg-Landau equation and a microscopic approach to calculate the interface shape. For the single corner system, we also discuss a correspondence between the interface and the Young diagram that represents the partition of the integers.
Solution of the stochastic control problem in unbounded domains.
NASA Technical Reports Server (NTRS)
Robinson, P.; Moore, J.
1973-01-01
Bellman's dynamic programming equation for the optimal index and control law for stochastic control problems is a parabolic or elliptic partial differential equation frequently defined in an unbounded domain. Existing methods of solution require bounded domain approximations, the application of singular perturbation techniques or Monte Carlo simulation procedures. In this paper, using the fact that Poisson impulse noise tends to a Gaussian process under certain limiting conditions, a method which achieves an arbitrarily good approximate solution to the stochastic control problem is given. The method uses the two iterative techniques of successive approximation and quasi-linearization and is inherently more efficient than existing methods of solution.
Dimension Analysis of Continuous Functions with Unbounded Variation
NASA Astrophysics Data System (ADS)
Wang, Jun; Yao, Kui
In this paper, we mainly discuss fractal dimensions of continuous functions with unbounded variation. First, we prove that Hausdorff dimension, Packing dimension and Modified Box-counting dimension of continuous functions containing one UV point are 1. The above conclusion still holds for continuous functions containing finite UV points. More generally, we show the result that Hausdorff dimension of continuous functions containing countable UV points is 1 also. Finally, Box dimension of continuous functions containing countable UV points has been proved to be 1 when f(x) is self-similar.
Unbounded Periodic Solutions to Serrin's Overdetermined Boundary Value Problem
NASA Astrophysics Data System (ADS)
Fall, Mouhamed Moustapha; Minlend, Ignace Aristide; Weth, Tobias
2017-02-01
We study the existence of nontrivial unbounded domains {Ω} in RN such that the overdetermined problem {-Δ u = 1 quad in Ω}, quad u = 0, quad partial_{ν} u = const quad on partial Ω admits a solution u. By this, we complement Serrin's classification result from 1971, which yields that every bounded domain admitting a solution of the above problem is a ball in RN. The domains we construct are periodic in some variables and radial in the other variables, and they bifurcate from a straight (generalized) cylinder or slab. We also show that these domains are uniquely self Cheeger relative to a period cell for the problem.
United States. Bonneville Power Administration.
1992-09-01
Since lighting accounts for about one-third of the energy used in commercial buildings, there is opportunity to conserve. There are two ways to reduce lighting energy use: modify lighting systems so that they used less electricity and/or reduce the number of hours the lights are used. This booklet presents a number of ways to do both. Topics covered include: reassessing lighting levels, reducing lighting levels, increasing bulb & fixture efficiency, using controls to regulate lighting, and taking advantage of daylight.
Statistical Verification of Probabilistic Properties with Unbounded Until
NASA Astrophysics Data System (ADS)
Younes, Håkan L. S.; Clarke, Edmund M.; Zuliani, Paolo
We consider statistical (sampling-based) solution methods for verifying probabilistic properties with unbounded until. Statistical solution methods for probabilistic verification use sample execution trajectories for a system to verify properties with some level of confidence. The main challenge with properties that are expressed using unbounded until is to ensure termination in the face of potentially infinite sample execution trajectories. We describe two alternative solution methods, each one with its own merits. The first method relies on reachability analysis, and is suitable primarily for large Markov chains where reachability analysis can be performed efficiently using symbolic data structures, but for which numerical probability computations are expensive. The second method employs a termination probability and weighted sampling. This method does not rely on any specific structure of the model, but error control is more challenging. We show how the choice of termination probability - when applied to Markov chains - is tied to the subdominant eigenvalue of the transition probability matrix, which relates it to iterative numerical solution techniques for the same problem.
Unbound or distant planetary mass population detected by gravitational microlensing.
2011-05-19
Since 1995, more than 500 exoplanets have been detected using different techniques, of which 12 were detected with gravitational microlensing. Most of these are gravitationally bound to their host stars. There is some evidence of free-floating planetary-mass objects in young star-forming regions, but these objects are limited to massive objects of 3 to 15 Jupiter masses with large uncertainties in photometric mass estimates and their abundance. Here, we report the discovery of a population of unbound or distant Jupiter-mass objects, which are almost twice (1.8(+1.7)(-0.8)) as common as main-sequence stars, based on two years of gravitational microlensing survey observations towards the Galactic Bulge. These planetary-mass objects have no host stars that can be detected within about ten astronomical units by gravitational microlensing. However, a comparison with constraints from direct imaging suggests that most of these planetary-mass objects are not bound to any host star. An abrupt change in the mass function at about one Jupiter mass favours the idea that their formation process is different from that of stars and brown dwarfs. They may have formed in proto-planetary disks and subsequently scattered into unbound or very distant orbits.
Description of weakly bound or unbound nuclear states
Kruppa, A.T.; Nazarewicz, W.
2004-09-13
A major theoretical challenge when dealing with weakly bound nuclei is to obtain a consistent microscopic description of bound states, resonances, and the non-resonant continuum. In this talk, resonances in deformed nuclei are described within the coupled-channel approach employing the Gamow state formalism. The coupled-channel method is compared with the expansion schemes employing the harmonic oscillator basis and the Berggren ensemble.
Winter, Thomas G.
2004-04-01
Cross sections have been determined for direct excitation, ionization, and electron transfer in collisions between H, He, Li, and Be nuclei and C{sup 5+}(1s) target ions at nuclear energies 1-24 MeV/nucleon, extending earlier work [Phys. Rev. A 56, 2903 (1997)] to higher energies. Coupled Sturmian pseudostates of principal quantum number at least up to 30 have been included for each angular momentum s, p, d, and f centered on the C nucleus, as well as a 1s state centered on the projectile. Detailed basis-convergence studies have been carried out. Cross sections have been compared with the corresponding Born results, and scaling rules have also been examined.
Ensemble-based characterization of unbound and bound states on protein energy landscape
Ruvinsky, Anatoly M; Kirys, Tatsiana; Tuzikov, Alexander V; Vakser, Ilya A
2013-01-01
Physicochemical description of numerous cell processes is fundamentally based on the energy landscapes of protein molecules involved. Although the whole energy landscape is difficult to reconstruct, increased attention to particular targets has provided enough structures for mapping functionally important subspaces associated with the unbound and bound protein structures. The subspace mapping produces a discrete representation of the landscape, further called energy spectrum. We compiled and characterized ensembles of bound and unbound conformations of six small proteins and explored their spectra in implicit solvent. First, the analysis of the unbound-to-bound changes points to conformational selection as the binding mechanism for four proteins. Second, results show that bound and unbound spectra often significantly overlap. Moreover, the larger the overlap the smaller the root mean square deviation (RMSD) between the bound and unbound conformational ensembles. Third, the center of the unbound spectrum has a higher energy than the center of the corresponding bound spectrum of the dimeric and multimeric states for most of the proteins. This suggests that the unbound states often have larger entropy than the bound states. Fourth, the exhaustively long minimization, making small intrarotamer adjustments (all-atom RMSD ≤ 0.7 Å), dramatically reduces the distance between the centers of the bound and unbound spectra as well as the spectra extent. It condenses unbound and bound energy levels into a thin layer at the bottom of the energy landscape with the energy spacing that varies between 0.8–4.6 and 3.5–10.5 kcal/mol for the unbound and bound states correspondingly. Finally, the analysis of protein energy fluctuations showed that protein vibrations itself can excite the interstate transitions, including the unbound-to-bound ones. PMID:23526684
Hegyi, Thomas; Kathiravan, Suganya; Stahl, Gary E; Huber, Andrew H; Kleinfeld, Alan
2013-01-01
Extremely low birth weight (ELBW; <1,000 g) infants have poor outcomes, often compromised by bilirubin neurotoxicity. We measured unbound bilirubin (Bf) and unbound free fatty acid (FFAu) levels in 5 ELBW infants in a trial examining the effects of pharmacologic ductal closure on infants treated with Intralipid infusion (3 g/kg/day). The levels for all infants (mean ± SD) were: total serum bilirubin (TSB) 4.6 ± 1.7 mg/dl, FFAu 376 ± 496 nM, and Bf 42 ± 30 nM. Of the 3 infants who died, 2 had TSB <5.9 mg/dl but FFAu >580 nM and Bf >75 nM. Multiple regression revealed a major effect on Bf levels due to FFAu, indicating that Intralipid elevated levels of FFAu and Bf. Indomethacin or ibuprofen reduced Bf levels, most likely by reducing FFAu levels through lipase inhibition. Because displacement of Bf by FFAu decouples Bf from TSB, phototherapy may not reduce the risk of bilirubin or FFAu toxicity in Intralipid-treated ELBW infants.
NASA Astrophysics Data System (ADS)
Penionzhkevich, Yu. E.
2012-07-01
Recently the academic community has marked several anniversaries connected with discoveries that played a significant role in the development of astrophysical investigations. The year 2009 was proclaimed by the United Nations the International Year of Astronomy. This was associated with the 400th anniversary of Galileo Galilei's discovery of the optical telescope, which marked the beginning of regular research in the field of astronomy. An important contribution to not only the development of physics of the microcosm, but also to the understanding of processes occurring in the Universe, was the discovery of the atomic nucleus made by E. Rutherford 100 years ago. Since then the investigations in the fields of physics of particles and atomic nuclei have helped to understand many processes in the microcosm. Exactly 80 years ago, K. Yanski used a radio-telescope in order to receive the radiation from cosmic objects for the first time, and at the present time this research area of physics is the most efficient method for studying the properties of the Universe. Finally, the April 12, 1961 (50 years ago) launching of the first sputnik into space with a human being onboard, the Russian cosmonaut Yuri Gagarin, marked the beginning of exploration of the Universe with the direct participation of man. All these achievements considerably extended our ideas about the Universe. This work is an attempt to present some problems on the evolution of the Universe: the nucleosynthesis and cosmochronology from the standpoint of physics of particles and nuclei, in particular with the use of the latest results, obtained by means of radioactive nuclear beams. The comparison is made between the processes taking place in the Universe and the mechanisms of formation and decay of nuclei, as well as of their interaction at different energies. Examples are given to show the capabilities of nuclear-physics methods for studying cosmic objects and properties of the Universe. The results of
Water distribution in dentin matrices: bound vs. unbound water
Agee, Kelli A.; Prakki, Anuradha; Abu-Haimed, Tariq; Naguib, Ghada H.; Nawareg, Manar Abu; Tezvergil-Mutluay, Arzu; Scheffel, Debora L.S.; Chen, Chen; Jang, Seung Soon; Hwang, Hyea; Brackett, Martha; Grégoire, Geneviéve; Tay, Franklin R.; Breschi, Lorenzo; Pashley, David H.
2015-01-01
Objectives This work measured the amount of bound versus unbound water in completely-demineralized dentin. Methods Dentin beams prepared from extracted human teeth were completely demineralized, rinsed and dried to constant mass. They were rehydrated in 41% relative humidity (RH), while gravimetrically measuring their mass increase until the first plateau was reached at 0.064 (vacuum) or 0.116 g H2O/g dry mass (Drierite). The specimens were then exposed to 60% RH until attaining the second plateau at 0.220 (vacuum) or 0.191 g H2O/g dry mass (Drierite), and subsequently exposed to 99% RH until attaining the third plateau at 0.493 (vacuum) or 0.401 g H2O/g dry mass (Drierite). Results Exposure of the first layer of bound water to 0% RH for 5 min produced a −0.3% loss of bound water; in the second layer of bound water it caused a −3.3% loss of bound water; in the third layer it caused a −6% loss of bound water. Immersion in 100% ethanol or acetone for 5 min produced a 2.8 and 1.9% loss of bound water from the first layer, respectively; it caused a −4 and −7% loss of bound water in the second layer, respectively; and a −17 and −23% loss of bound water in the third layer.. Bound water represented 21–25% of total dentin water. Chemical dehydration of water-saturated dentin with ethanol/acetone for 1 min only removed between 25 to 35% of unbound water, respectively. Significance Attempts to remove bound water by evaporation were not very successful. Chemical dehydration with 100% acetone was more successful than 100% ethanol especially the third layer of bound water. Since unbound water represents between 75–79% of total matrix water, the more such water can be removed, the more resin can be infiltrated. PMID:25612786
Simulated unbound structures for benchmarking of protein docking in the DOCKGROUND resource.
Kirys, Tatsiana; Ruvinsky, Anatoly M; Singla, Deepak; Tuzikov, Alexander V; Kundrotas, Petras J; Vakser, Ilya A
2015-07-31
Proteins play an important role in biological processes in living organisms. Many protein functions are based on interaction with other proteins. The structural information is important for adequate description of these interactions. Sets of protein structures determined in both bound and unbound states are essential for benchmarking of the docking procedures. However, the number of such proteins in PDB is relatively small. A radical expansion of such sets is possible if the unbound structures are computationally simulated. The DOCKGROUND public resource provides data to improve our understanding of protein-protein interactions and to assist in the development of better tools for structural modeling of protein complexes, such as docking algorithms and scoring functions. A large set of simulated unbound protein structures was generated from the bound structures. The modeling protocol was based on 1 ns Langevin dynamics simulation. The simulated structures were validated on the ensemble of experimentally determined unbound and bound structures. The set is intended for large scale benchmarking of docking algorithms and scoring functions. A radical expansion of the unbound protein docking benchmark set was achieved by simulating the unbound structures. The simulated unbound structures were selected according to criteria from systematic comparison of experimentally determined bound and unbound structures. The set is publicly available at http://dockground.compbio.ku.edu.
Neutron-unbound states in {sup 25,26}F
Frank, N.; Albertson, D.; Luther, B.; Bailey, J.; Kasperczyk, M.; Smith, A.; Baumann, T.; Bazin, D.; Schiller, A.; Brown, B. A.; Gade, A.; Peters, W. A.; Thoennessen, M.; Brown, J.; DeYoung, P. A.; Finck, J. E.; Hinnefeld, J.; Howes, R.; Tostevin, J. A.
2011-09-15
Neutron-unbound states in {sup 25}F and {sup 26}F were populated via the reactions {sup 9}Be({sup 26}Ne,{sup 24}F + n) and {sup 9}Be({sup 26}Ne,{sup 25}F + n), respectively. A resonance close to the neutron separation energy in {sup 25}F was identified with a decay energy of 28{+-}4 keV. This resonance corresponds to an excited state in {sup 25}F at 4249{+-}116 keV assuming it decays to the ground state of {sup 24}F. Guided by shell-model calculations, a spin and parity of 1/2{sup -} can be assigned to this state. In the spectrum of {sup 26}F, which was produced in a nucleon-exchange reaction, there are indications for an excited state with a decay energy of {approx}270 keV.
Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Alekseev, I.; Aparin, A.; Arkhipkin, D.; Aschenauer, E. C.; Attri, A.; Averichev, G. S.; Bai, X.; Bairathi, V.; Bellwied, R.; Bhasin, A.; Bhati, A. K.; Bhattarai, P.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Bordyuzhin, I. G.; Bouchet, J.; Brandenburg, J. D.; Brandin, A. V.; Bunzarov, I.; Butterworth, J.; Caines, H.; Calderón de la Barca Sánchez, M.; Campbell, J. M.; Cebra, D.; Chakaberia, I.; Chaloupka, P.; Chang, Z.; Chatterjee, A.; Chattopadhyay, S.; Chen, J. H.; Chen, X.; Cheng, J.; Cherney, M.; Christie, W.; Contin, G.; Crawford, H. J.; Das, S.; De Silva, L. C.; Debbe, R. R.; Dedovich, T. G.; Deng, J.; Derevschikov, A. A.; di Ruzza, B.; Didenko, L.; Dilks, C.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Du, C. M.; Dunkelberger, L. E.; Dunlop, J. C.; Efimov, L. G.; Engelage, J.; Eppley, G.; Esha, R.; Evdokimov, O.; Eyser, O.; Fatemi, R.; Fazio, S.; Federic, P.; Fedorisin, J.; Feng, Z.; Filip, P.; Fisyak, Y.; Flores, C. E.; Fulek, L.; Gagliardi, C. A.; Garand, D.; Geurts, F.; Gibson, A.; Girard, M.; Greiner, L.; Grosnick, D.; Gunarathne, D. S.; Guo, Y.; Gupta, S.; Gupta, A.; Guryn, W.; Hamad, A. I.; Hamed, A.; Haque, R.; Harris, J. W.; He, L.; Heppelmann, S.; Heppelmann, S.; Hirsch, A.; Hoffmann, G. W.; Horvat, S.; Huang, T.; Huang, X.; Huang, B.; Huang, H. Z.; Huck, P.; Humanic, T. J.; Igo, G.; Jacobs, W. W.; Jang, H.; Jentsch, A.; Jia, J.; Jiang, K.; Judd, E. G.; Kabana, S.; Kalinkin, D.; Kang, K.; Kauder, K.; Ke, H. W.; Keane, D.; Kechechyan, A.; Khan, Z. H.; Kikoła, D. P.; Kisel, I.; Kisiel, A.; Kochenda, L.; Koetke, D. D.; Kosarzewski, L. K.; Kraishan, A. F.; Kravtsov, P.; Krueger, K.; Kumar, L.; Lamont, M. A. C.; Landgraf, J. M.; Landry, K. D.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, J. H.; Li, X.; Li, C.; Li, X.; Li, Y.; Li, W.; Lin, T.; Lisa, M. A.; Liu, F.; Ljubicic, T.; Llope, W. J.; Lomnitz, M.; Longacre, R. S.; Luo, X.; Ma, R.; Ma, G. L.; Ma, Y. G.; Ma, L.; Magdy, N.; Majka, R.; Manion, A.; Margetis, S.; Markert, C.; Matis, H. S.; McDonald, D.; McKinzie, S.; Meehan, K.; Mei, J. C.; Minaev, N. G.; Mioduszewski, S.; Mishra, D.; Mohanty, B.; Mondal, M. M.; Morozov, D. A.; Mustafa, M. K.; Nandi, B. K.; Nasim, Md.; Nayak, T. K.; Nigmatkulov, G.; Niida, T.; Nogach, L. V.; Noh, S. Y.; Novak, J.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Oh, K.; Okorokov, V. A.; Olvitt, D.; Page, B. S.; Pak, R.; Pan, Y. X.; Pandit, Y.; Panebratsev, Y.; Pawlik, B.; Pei, H.; Perkins, C.; Pile, P.; Pluta, J.; Poniatowska, K.; Porter, J.; Posik, M.; Poskanzer, A. M.; Pruthi, N. K.; Putschke, J.; Qiu, H.; Quintero, A.; Ramachandran, S.; Raniwala, R.; Raniwala, S.; Ray, R. L.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Ruan, L.; Rusnak, J.; Rusnakova, O.; Sahoo, N. R.; Sahu, P. K.; Sakrejda, I.; Salur, S.; Sandweiss, J.; Sarkar, A.; Schambach, J.; Scharenberg, R. P.; Schmah, A. M.; Schmidke, W. B.; Schmitz, N.; Seger, J.; Seyboth, P.; Shah, N.; Shahaliev, E.; Shanmuganathan, P. V.; Shao, M.; Sharma, M. K.; Sharma, B.; Shen, W. Q.; Shi, Z.; Shi, S. S.; Shou, Q. Y.; Sichtermann, E. P.; Sikora, R.; Simko, M.; Singha, S.; Skoby, M. J.; Smirnov, N.; Smirnov, D.; Solyst, W.; Song, L.; Sorensen, P.; Spinka, H. M.; Srivastava, B.; Stanislaus, T. D. S.; Stepanov, M.; Stock, R.; Strikhanov, M.; Stringfellow, B.; Sumbera, M.; Summa, B.; Sun, X. M.; Sun, Z.; Sun, Y.; Surrow, B.; Svirida, D. N.; Tang, Z.; Tang, A. H.; Tarnowsky, T.; Tawfik, A.; Thäder, J.; Thomas, J. H.; Timmins, A. R.; Tlusty, D.; Todoroki, T.; Tokarev, M.; Trentalange, S.; Tribble, R. E.; Tribedy, P.; Tripathy, S. K.; Tsai, O. D.; Ullrich, T.; Underwood, D. G.; Upsal, I.; Van Buren, G.; van Nieuwenhuizen, G.; Vandenbroucke, M.; Varma, R.; Vasiliev, A. N.; Vertesi, R.; Videbæk, F.; Vokal, S.; Voloshin, S. A.; Vossen, A.; Wang, Y.; Wang, G.; Wang, J. S.; Wang, H.; Wang, Y.; Wang, F.; Webb, G.; Webb, J. C.; Wen, L.; Westfall, G. D.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, Y.; Xiao, Z. G.; Xie, W.; Xie, G.; Xin, K.; Xu, H.; Xu, Z.; Xu, J.; Xu, Y. F.; Xu, Q. H.; Xu, N.; Yang, Y.; Yang, S.; Yang, C.; Yang, Y.; Yang, Y.; Yang, Q.; Ye, Z.; Ye, Z.; Yepes, P.; Yi, L.; Yip, K.; Yoo, I. -K.; Yu, N.; Zbroszczyk, H.; Zha, W.; Zhang, J.; Zhang, Y.; Zhang, X. P.; Zhang, Z.; Zhang, J. B.; Zhang, S.; Zhang, S.; Zhang, J.; Zhao, J.; Zhong, C.; Zhou, L.; Zhu, X.; Zoulkarneeva, Y.; Zyzak, M.
2016-09-23
Here we present measurements of second-order azimuthal anisotropy ( v_{2} ) at midrapidity ( |y| < 1.0 ) for light nuclei d , t , ^{3}He (for $\\sqrt{s}$$_{NN}$ = 200 , 62.4, 39, 27, 19.6, 11.5, and 7.7 GeV) and antinuclei$\\bar{d}$ ( $\\sqrt{s}$$_{NN}$ = 200 , 62.4, 39, 27, and 19.6 GeV) and 3 ¯¯¯¯¯ He ( $\\sqrt{s}$$_{NN}$ = 200 GeV) in the STAR (Solenoidal Tracker at RHIC) experiment. The v_{2} for these light nuclei produced in heavy-ion collisions is compared with those for p and $\\bar{p}$. We observe mass ordering in nuclei v_{2} ( p_{T}) at low transverse momenta ( p_{T} < 2.0 GeV/c). We also find a centrality dependence of v_{2} for d and $\\bar{d}$ . The magnitude of v_{2} for t and ^{3}He agree within statistical errors. Light-nuclei v_{2} are compared with predictions from a blast-wave model. Atomic mass number ( A ) scaling of light-nuclei v_{2} (p_{T}) seems to hold for p_{T} / A < 1.5 GeV/c . Results on light-nuclei v_{2} from a transport-plus-coalescence model are consistent with the experimental measurements.
Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Alekseev, I.; Aparin, A.; Arkhipkin, D.; Aschenauer, E. C.; Attri, A.; Averichev, G. S.; Bai, X.; Bairathi, V.; Bellwied, R.; Bhasin, A.; Bhati, A. K.; Bhattarai, P.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Bordyuzhin, I. G.; Bouchet, J.; Brandenburg, J. D.; Brandin, A. V.; Bunzarov, I.; Butterworth, J.; Caines, H.; Calderón de la Barca Sánchez, M.; Campbell, J. M.; Cebra, D.; Chakaberia, I.; Chaloupka, P.; Chang, Z.; Chatterjee, A.; Chattopadhyay, S.; Chen, J. H.; Chen, X.; Cheng, J.; Cherney, M.; Christie, W.; Contin, G.; Crawford, H. J.; Das, S.; De Silva, L. C.; Debbe, R. R.; Dedovich, T. G.; Deng, J.; Derevschikov, A. A.; di Ruzza, B.; Didenko, L.; Dilks, C.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Du, C. M.; Dunkelberger, L. E.; Dunlop, J. C.; Efimov, L. G.; Engelage, J.; Eppley, G.; Esha, R.; Evdokimov, O.; Eyser, O.; Fatemi, R.; Fazio, S.; Federic, P.; Fedorisin, J.; Feng, Z.; Filip, P.; Fisyak, Y.; Flores, C. E.; Fulek, L.; Gagliardi, C. A.; Garand, D.; Geurts, F.; Gibson, A.; Girard, M.; Greiner, L.; Grosnick, D.; Gunarathne, D. S.; Guo, Y.; Gupta, S.; Gupta, A.; Guryn, W.; Hamad, A. I.; Hamed, A.; Haque, R.; Harris, J. W.; He, L.; Heppelmann, S.; Heppelmann, S.; Hirsch, A.; Hoffmann, G. W.; Horvat, S.; Huang, T.; Huang, X.; Huang, B.; Huang, H. Z.; Huck, P.; Humanic, T. J.; Igo, G.; Jacobs, W. W.; Jang, H.; Jentsch, A.; Jia, J.; Jiang, K.; Judd, E. G.; Kabana, S.; Kalinkin, D.; Kang, K.; Kauder, K.; Ke, H. W.; Keane, D.; Kechechyan, A.; Khan, Z. H.; Kikoła, D. P.; Kisel, I.; Kisiel, A.; Kochenda, L.; Koetke, D. D.; Kosarzewski, L. K.; Kraishan, A. F.; Kravtsov, P.; Krueger, K.; Kumar, L.; Lamont, M. A. C.; Landgraf, J. M.; Landry, K. D.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, J. H.; Li, X.; Li, C.; Li, X.; Li, Y.; Li, W.; Lin, T.; Lisa, M. A.; Liu, F.; Ljubicic, T.; Llope, W. J.; Lomnitz, M.; Longacre, R. S.; Luo, X.; Ma, R.; Ma, G. L.; Ma, Y. G.; Ma, L.; Magdy, N.; Majka, R.; Manion, A.; Margetis, S.; Markert, C.; Matis, H. S.; McDonald, D.; McKinzie, S.; Meehan, K.; Mei, J. C.; Minaev, N. G.; Mioduszewski, S.; Mishra, D.; Mohanty, B.; Mondal, M. M.; Morozov, D. A.; Mustafa, M. K.; Nandi, B. K.; Nasim, Md.; Nayak, T. K.; Nigmatkulov, G.; Niida, T.; Nogach, L. V.; Noh, S. Y.; Novak, J.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Oh, K.; Okorokov, V. A.; Olvitt, D.; Page, B. S.; Pak, R.; Pan, Y. X.; Pandit, Y.; Panebratsev, Y.; Pawlik, B.; Pei, H.; Perkins, C.; Pile, P.; Pluta, J.; Poniatowska, K.; Porter, J.; Posik, M.; Poskanzer, A. M.; Pruthi, N. K.; Putschke, J.; Qiu, H.; Quintero, A.; Ramachandran, S.; Raniwala, R.; Raniwala, S.; Ray, R. L.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Ruan, L.; Rusnak, J.; Rusnakova, O.; Sahoo, N. R.; Sahu, P. K.; Sakrejda, I.; Salur, S.; Sandweiss, J.; Sarkar, A.; Schambach, J.; Scharenberg, R. P.; Schmah, A. M.; Schmidke, W. B.; Schmitz, N.; Seger, J.; Seyboth, P.; Shah, N.; Shahaliev, E.; Shanmuganathan, P. V.; Shao, M.; Sharma, M. K.; Sharma, B.; Shen, W. Q.; Shi, Z.; Shi, S. S.; Shou, Q. Y.; Sichtermann, E. P.; Sikora, R.; Simko, M.; Singha, S.; Skoby, M. J.; Smirnov, N.; Smirnov, D.; Solyst, W.; Song, L.; Sorensen, P.; Spinka, H. M.; Srivastava, B.; Stanislaus, T. D. S.; Stepanov, M.; Stock, R.; Strikhanov, M.; Stringfellow, B.; Sumbera, M.; Summa, B.; Sun, X. M.; Sun, Z.; Sun, Y.; Surrow, B.; Svirida, D. N.; Tang, Z.; Tang, A. H.; Tarnowsky, T.; Tawfik, A.; Thäder, J.; Thomas, J. H.; Timmins, A. R.; Tlusty, D.; Todoroki, T.; Tokarev, M.; Trentalange, S.; Tribble, R. E.; Tribedy, P.; Tripathy, S. K.; Tsai, O. D.; Ullrich, T.; Underwood, D. G.; Upsal, I.; Van Buren, G.; van Nieuwenhuizen, G.; Vandenbroucke, M.; Varma, R.; Vasiliev, A. N.; Vertesi, R.; Videbæk, F.; Vokal, S.; Voloshin, S. A.; Vossen, A.; Wang, Y.; Wang, G.; Wang, J. S.; Wang, H.; Wang, Y.; Wang, F.; Webb, G.; Webb, J. C.; Wen, L.; Westfall, G. D.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, Y.; Xiao, Z. G.; Xie, W.; Xie, G.; Xin, K.; Xu, H.; Xu, Z.; Xu, J.; Xu, Y. F.; Xu, Q. H.; Xu, N.; Yang, Y.; Yang, S.; Yang, C.; Yang, Y.; Yang, Y.; Yang, Q.; Ye, Z.; Ye, Z.; Yepes, P.; Yi, L.; Yip, K.; Yoo, I. -K.; Yu, N.; Zbroszczyk, H.; Zha, W.; Zhang, J.; Zhang, Y.; Zhang, X. P.; Zhang, Z.; Zhang, J. B.; Zhang, S.; Zhang, S.; Zhang, J.; Zhao, J.; Zhong, C.; Zhou, L.; Zhu, X.; Zoulkarneeva, Y.; Zyzak, M.
2016-09-23
Here we present measurements of second-order azimuthal anisotropy ( v_{2} ) at midrapidity ( |y| < 1.0 ) for light nuclei d , t , ^{3}He (for $\\sqrt{s}$$_{NN}$ = 200 , 62.4, 39, 27, 19.6, 11.5, and 7.7 GeV) and antinuclei$\\bar{d}$ ( $\\sqrt{s}$$_{NN}$ = 200 , 62.4, 39, 27, and 19.6 GeV) and 3 ¯¯¯¯¯ He ( $\\sqrt{s}$$_{NN}$ = 200 GeV) in the STAR (Solenoidal Tracker at RHIC) experiment. The v_{2} for these light nuclei produced in heavy-ion collisions is compared with those for p and $\\bar{p}$. We observe mass ordering in nuclei v_{2} ( p_{T}) at low transverse momenta ( p_{T} < 2.0 GeV/c). We also find a centrality dependence of v_{2} for d and $\\bar{d}$ . The magnitude of v_{2} for t and ^{3}He agree within statistical errors. Light-nuclei v_{2} are compared with predictions from a blast-wave model. Atomic mass number ( A ) scaling of light-nuclei v_{2} (p_{T}) seems to hold for p_{T} / A < 1.5 GeV/c . Results on light-nuclei v_{2} from a transport-plus-coalescence model are consistent with the experimental measurements.
How to avoid unbounded drug accumulation with fractional pharmacokinetics.
Hennion, Maud; Hanert, Emmanuel
2013-12-01
A number of studies have shown that certain drugs follow an anomalous kinetics that can hardly be represented by classical models. Instead, fractional-order pharmacokinetics models have proved to be better suited to represent the time course of these drugs in the body. Unlike classical models, fractional models can represent memory effects and a power-law terminal phase. They give rise to a more complex kinetics that better reflects the complexity of the human body. By doing so, they also spotlight potential issues that were ignored by classical models. Among those issues is the accumulation of drug that carries on indefinitely when the infusion rate is constant and the elimination flux is fractional. Such an unbounded accumulation could have important clinical implications and thus requires a solution to reach a steady state. We have considered a fractional one-compartment model with a continuous intravenous infusion and studied how the infusion rate influences the total amount of drug in the compartment. By taking an infusion rate that decays like a power law, we have been able to stabilize the amount of drug in the compartment. In the case of multiple dosing administration, we propose recurrence relations for the doses and the dosing times that also prevent drug accumulation. By introducing a numerical discretization of the model equations, we have been able to consider a more realistic two-compartment model with both continuous infusion and multiple dosing administration. That numerical model has been applied to amiodarone, a drug known to have an anomalous kinetics. Numerical results suggest that unbounded drug accumulation can again be prevented by using a drug input function that decays as a power law.
Transient solutions to groundwater mounding in bounded and unbounded aquifers.
Korkmaz, Serdar
2013-01-01
In this study, the well-known Hantush solution procedure for groundwater mounding under infinitely long infiltration strips is extended to finite and semi-infinite aquifer cases. Initially, the solution for infinite aquifers is presented and compared to those available in literature and to the numerical results of MODFLOW. For the finite aquifer case, the method of images, which is commonly used in well hydraulics, is used to be able to represent the constant-head boundaries at both sides. It is shown that a finite number of images is enough to obtain the results and sustain the steady state. The effect of parameters on the growth of the mound and on the time required to reach the steady state is investigated. The semi-infinite aquifer case is emphasized because the growth of the mound is not symmetric. As the constant-head boundary limits the growth, the unbounded side grows continuously. For this reason, the groundwater divide shifts toward the unbounded side. An iterative solution procedure is proposed. To perform the necessary computations a code was written in Visual Basic of which the algorithm is presented. The proposed methodology has a wide range of applicability and this is demonstrated using two practical examples. The first one is mounding under a stormwater dispersion trench in an infinite aquifer and the other is infiltration from a flood control channel into a semi-infinite aquifer. Results fit very well with those of MODFLOW. © 2012, The Author(s). Groundwater © 2012, National Ground Water Association.
Piarulli, M.; Girlanda, L.; Schiavilla, R.; Kievsky, A.; Lovato, A.; Marcucci, L. E.; Pieper, Steven C.; Viviani, M.; Wiringa, R. B.
2016-11-01
We present fully local versions of the minimally non-local nucleon-nucleon potentials constructed in a previous paper [M.\\ Piarulli {\\it et al.}, Phys.\\ Rev.\\ C {\\bf 91}, 024003 (2015)], and use them in hypersperical-harmonics and quantum Monte Carlo calculations of ground and excited states of $^3$H/$^3$He, $^4$He, and $^6$He/$^6$Li nuclei. The long-range part of these local potentials includes one- and two-pion exchange contributions without and with $\\Delta$-isobars in the intermediate states up to order $Q^3$ ($Q$ denotes generically the low momentum scale) in the chiral expansion, while the short-range part consists of contact interactions up to order $Q^4$. The low-energy constants multiplying these contact interactions are fitted to the 2013 Granada database in two different ranges of laboratory energies, either 0--125 MeV or 0--200 MeV, and to the deuteron binding energy and $nn$ singlet scattering length. Fits to these data are performed for three models characterized by long- and short-range cutoffs, $R_{\\rm L}$ and $R_{\\rm S}$ respectively, ranging from $(R_{\\rm L},R_{\\rm S})=(1.2,0.8)$ fm down to $(0.8,0.6)$ fm. The long-range (short-range) cutoff regularizes the one- and two-pion exchange (contact) part of the potential.
2016-01-01
Light-induced chloroplast movement and attachment to the plasma membrane are dependent on actin filaments. In Arabidopsis thaliana, the short actin filaments on the chloroplast envelope, cp-actin filaments, are essential for chloroplast movement and positioning. Furthermore, cp-actin-filament-mediated chloroplast movement is necessary for the strong-light-induced nuclear avoidance response. The proteins CHLOROPLAST UNUSUAL POSITIONING 1 (CHUP1), KINESIN-LIKE PROTEIN FOR ACTIN-BASED CHLOROPLAST MOVEMENT 1 (KAC1) and KAC2 are required for the generation and/or maintenance of cp-actin filaments in Arabidopsis. In land plants, CHUP1 and KAC family proteins play pivotal roles in the proper movement of chloroplasts and their attachment to the plasma membrane. Here, we report similar but distinct phenotypes in chloroplast and nuclear photorelocation movements between chup1 and kac1kac2 mutants. Measurement of chloroplast photorelocation movement indicated that kac1kac2, but not chup1, exhibited a clear strong-light-induced increase in leaf transmittance changes. The chloroplast movement in kac1kac2 depended on phototropin 2, CHUP1 and two other regulators for cp-actin filaments, PLASTID MOVEMENT IMPAIRED 1 and THRUMIN 1. Furthermore, kac1kac2 retained a weak but significant nuclear avoidance response although chup1 displayed a severe defect in the nuclear avoidance response. The kac1kac2chup1 triple mutant was completely defective in both chloroplast and nuclear avoidance responses. These results indicate that CHUP1 and the KACs function somewhat independently, but interdependently mediate both chloroplast and nuclear photorelocation movements. PMID:27310016
Suetsugu, Noriyuki; Higa, Takeshi; Gotoh, Eiji; Wada, Masamitsu
2016-01-01
Light-induced chloroplast movement and attachment to the plasma membrane are dependent on actin filaments. In Arabidopsis thaliana, the short actin filaments on the chloroplast envelope, cp-actin filaments, are essential for chloroplast movement and positioning. Furthermore, cp-actin-filament-mediated chloroplast movement is necessary for the strong-light-induced nuclear avoidance response. The proteins CHLOROPLAST UNUSUAL POSITIONING 1 (CHUP1), KINESIN-LIKE PROTEIN FOR ACTIN-BASED CHLOROPLAST MOVEMENT 1 (KAC1) and KAC2 are required for the generation and/or maintenance of cp-actin filaments in Arabidopsis. In land plants, CHUP1 and KAC family proteins play pivotal roles in the proper movement of chloroplasts and their attachment to the plasma membrane. Here, we report similar but distinct phenotypes in chloroplast and nuclear photorelocation movements between chup1 and kac1kac2 mutants. Measurement of chloroplast photorelocation movement indicated that kac1kac2, but not chup1, exhibited a clear strong-light-induced increase in leaf transmittance changes. The chloroplast movement in kac1kac2 depended on phototropin 2, CHUP1 and two other regulators for cp-actin filaments, PLASTID MOVEMENT IMPAIRED 1 and THRUMIN 1. Furthermore, kac1kac2 retained a weak but significant nuclear avoidance response although chup1 displayed a severe defect in the nuclear avoidance response. The kac1kac2chup1 triple mutant was completely defective in both chloroplast and nuclear avoidance responses. These results indicate that CHUP1 and the KACs function somewhat independently, but interdependently mediate both chloroplast and nuclear photorelocation movements.
Fabian, Andrew C.
1999-01-01
Active galactic nuclei are the most powerful, long-lived objects in the Universe. Recent data confirm the theoretical idea that the power source is accretion into a massive black hole. The common occurrence of obscuration and outflows probably means that the contribution of active galactic nuclei to the power density of the Universe has been generally underestimated. PMID:10220363
NASA Astrophysics Data System (ADS)
Vernon, C. G.
2016-09-01
Preface; 1. Historical; 2. Waves and wave-motion; 3. The behaviour of ripples; 4. The behaviour of light; 5. Refraction through glass blocks and prisms; 6. The imprinting of curvatures; 7. Simple mathematical treatment; 8. More advanced mathematical treatment; 9. The velocity of light; 10. The spectrum and colour; 11. Geometrical optics; 12. The eye and optical instruments; 13. Sources of light; 14. Interference, diffraction and polarisation; 15. Suggestions for class experiments; Index.
Stove, Veronique; Coene, Louise; Carlier, Mieke; De Waele, Jan J; Fiers, Tom; Verstraete, Alain G
2015-04-01
Studies on the unbound fraction (fu) of vancomycin report highly variable results. Great controversy also exists about the correlation between unbound and total vancomycin concentrations. As differences in (pre-)analytic techniques may explain these findings, we investigated the impact of the procedure used to isolate unbound vancomycin in serum/plasma on fu and the correlation between total and unbound concentrations. Patient samples (n = 39) were analyzed for total and unbound vancomycin concentrations after ultrafiltration (UF, Centrifree at 4°C and 37°C) or equilibrium dialysis (ED, using a Fast Micro-Equilibrium Dialyzer at 37°C) on an Architect i2000SR. To investigate correlations with potential binding proteins, total protein, albumin, alpha-1-acid glycoprotein, and IgA concentrations were also measured. The median fu after ED was 72.5% [interquartile range (IQR), 68.7%-75.0%]. Ultrafiltration at 4°C and 37°C resulted in a median fu of 51.6% (IQR, 48.6%-54.8%) and 75.2% (IQR, 69.3%-78.6%), respectively, with no significant difference between unbound vancomycin concentrations after ED and UF at 37°C (P = 0.13). Unbound concentrations obtained through ED and UF correlated linearly (4°C: r = 0.9457; 37°C: r = 0.9478; both P < 0.0001). Linear mixed-model regression showed that total vancomycin as such was the predominant determinant for the unbound concentration, allowing a reliable prediction (mean bias ± SD, 5.0% ± 7.6%). The studied protein concentrations were of no added value in predicting the unbound concentration. Vancomycin fu after UF at 4°C was on average 30.6% lower than that after UF at 37°C, demonstrating the importance of temperature during UF. Ultrafiltration at 37°C resulted in unbound vancomycin concentrations equivalent with ED. As the unbound concentration could be reliably predicted based on total vancomycin concentrations as such, measurement of unbound vancomycin concentrations has little added value over measurements of total
Klimentowski, Jaroslaw; Lokas, Ewa L.; Kazantzidis, Stelios; Prada, Francisco; Mayer, Lucio; Mamon, Gary A.; /Paris, Inst. Astrophys. /Meudon Observ.
2006-11-14
We study the origin and properties of the population of unbound stars in the kinematic samples of dwarf spheroidal galaxies. For this purpose we have run a high resolution N- body simulation of a two-component dwarf galaxy orbiting in a Milky Way potential. In agreement with the tidal stirring scenario of Mayer et al., the dwarf is placed on a highly eccentric orbit, its initial stellar component is in the form of an exponential disk and it has a NFW-like dark matter halo. After 10 Gyrs of evolution the dwarf produces a spheroidal stellar component and is strongly tidally stripped so that mass follows light and the stars are on almost isotropic orbits. From this final state, we create mock kinematic data sets for 200 stars by observing the dwarf in different directions.We find that when the dwarf is observed along the tidal tails the kinematic samples are strongly contaminated by unbound stars from the tails.We also study another source of possible contamination by adding stars from the Milky Way. We demonstrate that most of the unbound stars can be removed by the method of interloper rejection proposed by den Hartog & Katgert and recently tested on simulated dark matter haloes. We model the cleaned up kinematic samples using solutions of the Jeans equation with constant mass-to-light ratio and velocity anisotropy parameter. We show that even for such strongly stripped dwarf the Jeans analysis, when applied to cleaned samples, allows us to reproduce the mass and mass-to-light ratio of the dwarf with accuracy typically better than 25 percent and almost exactly in the case when the line of sight is perpendicular to the tidal tails. The analysis was applied to the new data for the Fornax dSph galaxy for which we find a mass-to-light ratio of 11 solar units and isotropic orbits. We demonstrate that most of the contamination in the kinematic sample of Fornax probably originates from the Milky Way.
Estimation of Bounded and Unbounded Trajectories in Diffusion MRI
Ning, Lipeng; Westin, Carl-Fredrik; Rathi, Yogesh
2016-01-01
Disentangling the tissue microstructural information from the diffusion magnetic resonance imaging (dMRI) measurements is quite important for extracting brain tissue specific measures. The autocorrelation function of diffusing spins is key for understanding the relation between dMRI signals and the acquisition gradient sequences. In this paper, we demonstrate that the autocorrelation of diffusion in restricted or bounded spaces can be well approximated by exponential functions. To this end, we propose to use the multivariate Ornstein-Uhlenbeck (OU) process to model the matrix-valued exponential autocorrelation function of three-dimensional diffusion processes with bounded trajectories. We present detailed analysis on the relation between the model parameters and the time-dependent apparent axon radius and provide a general model for dMRI signals from the frequency domain perspective. For our experimental setup, we model the diffusion signal as a mixture of two compartments that correspond to diffusing spins with bounded and unbounded trajectories, and analyze the corpus-callosum in an ex-vivo data set of a monkey brain. PMID:27064745
The properties of energetically unbound stars in stellar clusters
NASA Astrophysics Data System (ADS)
Claydon, Ian; Gieles, Mark; Zocchi, Alice
2017-04-01
Several Milky Way star clusters show a roughly flat velocity dispersion profile at large radii, which is not expected from models with a tidal cut-off energy. Possible explanations for this excess velocity include the effects of a dark matter halo, modified gravity theories and energetically unbound stars inside of clusters. These stars are known as potential escapers (PEs) and can exist indefinitely within clusters that are on circular orbits. Through a series of N-body simulations of star cluster systems, where we vary the galactic potential, orbital eccentricity and stellar mass function, we investigate the properties of the PEs and their effects on the kinematics. We derive a prediction for the scaling of the velocity dispersion at the Jacobi surface due to PEs, as a function of cluster mass, angular velocity of the cluster orbit, and slope of the mass profile of the host galaxy. We see a tentative signal of the mass and orbital velocity dependence in kinematic data of globular clusters from the literature. We also find that the fraction of PEs depends sensitively on the galactic mass profile, reaching as high as 40 per cent in the cusp of a Navarro-Frenk-White profile and as the velocity anisotropy also depends on the slope of the galactic mass profile, we conclude that PEs provide an independent way of inferring the properties of the dark matter mass profile at the galactic radius of (globular) clusters in the Gaia era.
Ab initio description of the exotic unbound 7He nucleus
Baroni, Simone; Navratil, Petr; Quaglioni, Sofia
2013-01-11
In this study, the neutron-rich unbound 7He nucleus has been the subject of many experimental investigations. While the ground-state 3/2– resonance is well established, there is a controversy concerning the excited 1/2– resonance reported in some experiments as low lying and narrow (ER~1 MeV, Γ≤1 MeV) while in others as very broad and located at a higher energy. This issue cannot be addressed by ab initio theoretical calculations based on traditional bound-state methods. We introduce a new unified approach to nuclear bound and continuum states based on the coupling of the no-core shell model, a bound-state technique, with the no-coremore » shell model combined with the resonating-group method, a nuclear scattering technique. Our calculations describe the ground-state resonance in agreement with experiment and, at the same time, predict a broad 1/2– resonance above 2 MeV.« less
Trivelpiece-Gould modes in a uniform unbounded plasma
Stenzel, R. L.; Urrutia, J. M.
2016-09-15
Trivelpiece-Gould (TG) modes originally described electrostatic surface waves on an axially magnetized cylindrical plasma column. Subsequent studies of electromagnetic waves in such plasma columns revealed two modes, a predominantly magnetic helicon mode (H) and the mixed magnetic and electrostatic Trivelpiece-Gould modes (TG). The latter are similar to whistler modes near the oblique cyclotron resonance in unbounded plasmas. The wave propagation in cylindrical geometry is assumed to be paraxial while the modes exhibit radial standing waves. The present work shows that TG modes also arise in a uniform plasma without radial standing waves. It is shown experimentally that oblique cyclotron resonance arises in large mode number helicons. Their azimuthal wave number far exceeds the axial wave number which creates whistlers near the oblique cyclotron resonance. Cyclotron damping absorbs the TG mode and can energize electrons in the center of a plasma column rather than the edge of conventional TG modes. The angular orbital field momentum can produce new perpendicular wave-particle interactions.
Unbound States of 32Cl Relevant for Novae
Matos, M.; Blackmon, Jeff C; Linhardt, Laura; Bardayan, Daniel W; Nesaraja, Caroline D; Clark, Jason; Diebel, C.; O'Malley, Patrick; Parker, P.D.; Schmitt, Kyle
2011-01-01
The 31S(p,g )32Cl proton capture reaction is expected to be the dominant breakout pathway of the SiP cycle, which is important for understanding nucleosynthesis in some novae [1]. At novae temperatures, the 31S(p,g )32Cl reaction rate is dominated by 31S+p resonances. Discrepancies in the 32Cl resonance energies were reported in previous measurements [1, 2]. We used the 32S(3He,t)32Cl charge exchange reaction to produce unbound states in 32Cl and determine their excitation energies by detecting tritons at the focal plane of the Enge Spectrograph at the Yale University s Wright Nuclear Structure Laboratory. Proton branching ratios were determined by detecting the decay protons coming from the residual 32Cl states using a silicon array in the spectrometer s target chamber. The improved energy values of excited levels in 32Cl and measurements of the proton-branching ratios should significantly improve our understanding of the 31S(p,g )32Cl reaction rate.
Tagging the Decay of Neutron Unbound States near the Dripline
NASA Astrophysics Data System (ADS)
Wersal, Alissa; Christian, Greg; Thoennessen, Michael; Spyrou, Artemis
2010-11-01
Near the neutron dripline the study of neutron-unbound states is a valuable spectroscopic tool. Neutron-decay spectroscopy experiments, however, only determine the relative energy of the resonances. If the neutron decays to a bound excited state, it is necessary to measure the γ-decay in order to determine the absolute excitation energy of the initial state. The CAESium iodide ARray (CAESAR) was used for the first time in coincidence with the MoNA/Sweeper setup at the NSCL to perform this type of experiment. A secondary 70 MeV/u ^32Mg beam produced at the Coupled Cyclotron Facility bombarded a 288 mg/cm^2 beryllium target. After the reaction, any charged particles were deflected by a superconducting 4T large-gap dipole magnet, and their positions, time of flight, and energy loss were measured. Neutrons were detected in coincidence with the Modular Neutron Array (MoNA) while CAESAR recorded any possible gamma rays. The Doppler shifted calibration of CAESAR was performed with gamma rays from Coulomb excited ^32Mg and from ^30Na fragments. Preliminary results will be presented.
Neutron radioactivity-Lifetime measurements of neutron-unbound states
NASA Astrophysics Data System (ADS)
Kahlbow, J.; Caesar, C.; Aumann, T.; Panin, V.; Paschalis, S.; Scheit, H.; Simon, H.
2017-09-01
A new technique to measure the lifetime τ of a neutron-radioactive nucleus that decays in-flight via neutron emission is presented and demonstrated utilizing MonteCarlo simulations. The method is based on the production of the neutron-unbound nucleus in a target, which at the same time slows down the produced nucleus and the residual nucleus after (multi-) neutron emission. The spectrum of the velocity difference of neutron(s) and the residual nucleus has a characteristic shape, that allows to extract the lifetime. If the decay happens outside the target there will be a peak in the spectrum, while events where the decay is in the target show a broad flat distribution due to the continuous slowing down of the residual nucleus. The method itself and the analysis procedure are discussed in detail for the specific candidate 26O. A stack of targets with decreasing target thicknesses can expand the measurable lifetime range and improve the sensitivity by increasing the ratio between decays outside and inside the target. The simulations indicate a lower limit of measurable lifetime τ ∼ 0 . 2 ps for the given conditions.
NASA Astrophysics Data System (ADS)
Ross, T. J.; Beausang, C. W.; Hughes, R. O.; Allmond, J. M.; Angell, C. T.; Basunia, M. S.; Bleuel, D. L.; Burke, J. T.; Casperson, R. J.; Escher, J. E.; Fallon, P.; Hatarik, R.; Munson, J.; Paschalis, S.; Petri, M.; Phair, L.; Ressler, J. J.; Scielzo, N. D.; Thompson, I. J.
2012-10-01
Historically it has proven extremely difficult to probe the properties of low-spin highly-excited states far above the yrast line in the bound quasi-continuum. We present the first measurement of the initial spin distribution of this region, following (p,d) and (p,t) reactions on ^154Gd and ^158Gd targets. The 25 MeV proton beam was provided by the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory. A silicon telescope array, STARS, was used to detect light ions. We find that the spin transferred increases with excitation energy. Between 3 and 8 MeV, assuming a single dominant angular momentum transfer component, the measured angular distribution for the (p,d) reactions are well reproduced by DWBA calculations for δL=4 transfer, whilst the (p,t) reactions are better characterized by δL=5. A weighted combination of DWBA calculations, agrees excellently with experimental angular distributions.
Is Fusion Inhibited for Weakly Bound Nuclei?
Takahashi, J.; Munhoz, M.; Szanto, E.M.; Carlin, N.; Added, N.; Suaide, A.A.; de Moura, M.M.; Liguori Neto, R.; Szanto de Toledo, A.; Canto, L.F.
1997-01-01
Complete fusion of light radioactive nuclei is predicted to be hindered at near-barrier energies. This feature is investigated in the case of the least bound stable nuclei. Evaporation residues resulting from the {sup 6,7}Li+{sup 9}Be and {sup 6,7}Li+{sup 12}C fusion reactions have been measured in order to study common features in reactions involving light weakly bound nuclei. The experimental excitation functions revealed that the fusion cross section is significantly smaller than the total reaction cross section and also smaller than the fusion cross section expected from the available systematics. A clear correlation between the fusion probability and nucleon (cluster) separation energy has been established.The results suggest that the breakup process has a strong influence on the hindrance of the fusion cross section. {copyright} {ital 1996} {ital The American Physical Society}
Nabbi, Arash; Riabowol, Karl
2015-08-03
The isolation of nuclei is often the first step in studying processes such as nuclear-cytoplasmic shuttling, subcellular localization of proteins, and protein-chromatin or nuclear protein-protein interactions in response to diverse stimuli. Therefore, rapidly obtaining nuclei from cells with relatively high purity and minimal subcellular contamination, protein degradation, or postharvesting modification is highly desirable. Historically, the isolation of nuclei involved a homogenization step followed by centrifugation through high-density glycerol or sucrose. Although clean nuclei with little cytoplasmic contamination can be prepared using this method, it is typically time consuming and can allow protein degradation, protein modification, and leaching of components from the nuclei to occur. We have developed a rapid and simple fractionation method that is based on the selective dissolution of the cytoplasmic membrane (but not the nuclear membrane) using a low concentration of a nonionic detergent and rapid centrifugation steps. Here we describe important considerations when isolating nuclei from cells, introduce our rapid method, and compare this method to a more traditional protocol for isolating nuclei, noting the strengths and limitations of each approach.
Strategies in unbounded number line estimation? Evidence from eye-tracking.
Reinert, Regina M; Huber, Stefan; Nuerk, Hans-Christoph; Moeller, Korbinian
2015-09-01
For bounded number line estimation, recent studies indicated influences of proportion-based strategies as documented by eye-tracking data. In the current study, we investigated solution strategies in bounded and unbounded number line estimation by directly comparing participants' estimation performance as well as their corresponding eye-fixation behaviour. For bounded number line estimation, increased numbers of fixations at and around reference points (i.e. start, middle and endpoint) confirmed the prominent use of proportion-based strategies. In contrast, in unbounded number line estimation, the number of fixations on the number line decreased continuously with increasing magnitude of the target number. Additionally, we observed that in bounded and unbounded number line estimation participants' first fixation on the number line was a valid predictor of the location of the target number. In sum, these data corroborate the idea that unbounded number line estimation is less influenced by proportion-based estimation strategies not directly related to numerical estimations.
21 CFR 862.1113 - Bilirubin (total and unbound) in the neonate test system.
Code of Federal Regulations, 2012 CFR
2012-04-01
... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1113 Bilirubin (total and unbound) in the neonate test system. (a...
21 CFR 862.1113 - Bilirubin (total and unbound) in the neonate test system.
Code of Federal Regulations, 2014 CFR
2014-04-01
... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1113 Bilirubin (total and unbound) in the neonate test system. (a...
21 CFR 862.1113 - Bilirubin (total and unbound) in the neonate test system.
Code of Federal Regulations, 2013 CFR
2013-04-01
... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1113 Bilirubin (total and unbound) in the neonate test system. (a...
21 CFR 862.1113 - Bilirubin (total and unbound) in the neonate test system.
Code of Federal Regulations, 2011 CFR
2011-04-01
... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1113 Bilirubin (total and unbound) in the neonate test system. (a...
The spectral theorem for quaternionic unbounded normal operators based on the S-spectrum
Alpay, Daniel Kimsey, David P.; Colombo, Fabrizio
2016-02-15
In this paper we prove the spectral theorem for quaternionic unbounded normal operators using the notion of S-spectrum. The proof technique consists of first establishing a spectral theorem for quaternionic bounded normal operators and then using a transformation which maps a quaternionic unbounded normal operator to a quaternionic bounded normal operator. With this paper we complete the foundation of spectral analysis of quaternionic operators. The S-spectrum has been introduced to define the quaternionic functional calculus but it turns out to be the correct object also for the spectral theorem for quaternionic normal operators. The lack of a suitable notion of spectrum was a major obstruction to fully understand the spectral theorem for quaternionic normal operators. A prime motivation for studying the spectral theorem for quaternionic unbounded normal operators is given by the subclass of unbounded anti-self adjoint quaternionic operators which play a crucial role in the quaternionic quantum mechanics.
NASA Astrophysics Data System (ADS)
Wodyński, Artur; Pecul, Magdalena
2014-01-01
The 1JCC and 1JCH spin-spin coupling constants have been calculated by means of density functional theory (DFT) for a set of derivatives of aliphatic hydrocarbons substituted with I, At, Cd, and Hg in order to evaluate the substituent and relativistic effects for these properties. The main goal was to estimate HALA (heavy-atom-on-light-atom) effects on spin-spin coupling constants and to explore the factors which may influence the HALA effect on these properties, including the nature of the heavy atom substituent and carbon hybridization. The methods applied range, in order of reduced complexity, from Dirac-Kohn-Sham method (density functional theory with four-component Dirac-Coulomb Hamiltonian), through DFT with two- and one-component Zeroth Order Regular Approximation (ZORA) Hamiltonians, to scalar non-relativistic effective core potentials with the non-relativistic Hamiltonian. Thus, we are able to compare the performance of ZORA-DFT and Dirac-Kohn-Sham methods for modelling of the HALA effects on the spin-spin coupling constants.
Wodyński, Artur; Pecul, Magdalena
2014-01-14
The {sup 1}J{sub CC} and {sup 1}J{sub CH} spin-spin coupling constants have been calculated by means of density functional theory (DFT) for a set of derivatives of aliphatic hydrocarbons substituted with I, At, Cd, and Hg in order to evaluate the substituent and relativistic effects for these properties. The main goal was to estimate HALA (heavy-atom-on-light-atom) effects on spin-spin coupling constants and to explore the factors which may influence the HALA effect on these properties, including the nature of the heavy atom substituent and carbon hybridization. The methods applied range, in order of reduced complexity, from Dirac-Kohn-Sham method (density functional theory with four-component Dirac-Coulomb Hamiltonian), through DFT with two- and one-component Zeroth Order Regular Approximation (ZORA) Hamiltonians, to scalar non-relativistic effective core potentials with the non-relativistic Hamiltonian. Thus, we are able to compare the performance of ZORA-DFT and Dirac-Kohn-Sham methods for modelling of the HALA effects on the spin-spin coupling constants.
NASA Astrophysics Data System (ADS)
Klimentowski, Jarosław; Łokas, Ewa L.; Kazantzidis, Stelios; Prada, Francisco; Mayer, Lucio; Mamon, Gary A.
2007-06-01
We study the origin and properties of the population of unbound stars in the kinematic samples of dwarf spheroidal (dSph) galaxies. For this purpose we have run a high-resolution N-body simulation of a two-component dwarf galaxy orbiting in a Milky Way potential. In agreement with the tidal stirring scenario of Mayer et al., the dwarf is placed on a highly eccentric orbit, its initial stellar component is in the form of an exponential disc and it has a NFW-like dark matter (DM) halo. After 10 Gyr of evolution the dwarf produces a spheroidal stellar component and is strongly tidally stripped so that mass follows light and the stars are on almost isotropic orbits. From this final state, we create mock kinematic data sets for 200 stars by observing the dwarf in different directions. We find that when the dwarf is observed along the tidal tails the kinematic samples are strongly contaminated by unbound stars from the tails. We also study another source of possible contamination by adding stars from the Milky Way. We demonstrate that most of the unbound stars can be removed by the method of interloper rejection proposed by den Hartog & Katgert and recently tested on simulated DM haloes. We model the cleaned-up kinematic samples using solutions of the Jeans equation with constant mass-to-light ratio (M/L) and velocity anisotropy parameter. We show that even for such a strongly stripped dwarf the Jeans analysis, when applied to cleaned samples, allows us to reproduce the mass and M/L of the dwarf with accuracy typically better than 25 per cent and almost exactly in the case when the line of sight is perpendicular to the tidal tails. The analysis was applied to the new data for the Fornax dSph galaxy. We show that after careful removal of interlopers the velocity dispersion profile of Fornax can be reproduced by a model in which mass traces light with a M/L of 11 solar units and isotropic orbits. We demonstrate that most of the contamination in the kinematic sample of
Unbounded Trace Orbits of Thue-Morse Hamiltonian
NASA Astrophysics Data System (ADS)
Liu, Qinghui; Qu, Yanhui; Yao, Xiao
2017-03-01
It is well known that, an energy is in the spectrum of Fibonacci Hamiltonian if and only if the corresponding trace orbit is bounded. However, it is not known whether the same result holds for the Thue-Morse Hamiltonian. In this paper, we give a negative answer to this question. More precisely, we construct two subsets Σ _{II} and Σ _{III} of the spectrum of the Thue-Morse Hamiltonian, both of which are dense and uncountable, such that each energy in Σ _{II}\\cup Σ _{III} corresponds to an unbounded trace orbit. Exact estimates on the norm of the transfer matrices are also obtained for these energies: for Ein Σ _{II}\\cup Σ _{III}, the norms of the transfer matrices behave like e^{c_1γ √{n}}≤Vert T_{ n}(E)Vert ≤e^{c_2γ √{n}}. However, two types of energies are quite different in the sense that each energy in Σ _{II} is associated with a two-sided pseudo-localized state, while each energy in Σ _{III} is associated with a one-sided pseudo-localized state. The difference is also reflected by the local dimensions of the spectral measure: the local dimension is 0 for energies in Σ _{II} and is larger than 1 for energies in Σ _{III}. As a comparison, we mention another known countable dense subset Σ _I. Each energy in Σ _I corresponds to an eventually constant trace map and the associated eigenvector is an extended state. In summary, the Thue-Morse Hamiltonian exhibits "mixed spectral nature".
Rogue waves and unbounded solutions of the NLSE
NASA Astrophysics Data System (ADS)
Lechuga, Antonio
2017-04-01
Since the pioneering work of Zakharov has been generally admitted that rogue waves can be studied in the framework of the Nonlinear Schrödinger Equation (NLSE). Many researchers, Akhmediev, Peregrine, Matveev among others gave different solutions to this equation that, in some way, could be linked to rogue waves and also to its more important characteristic: its unexpectedness. Janssen (2003, 2004), Onorato (2004, 2006) and Waseda (2006) linked the coefficient of the nonlinear term of the Schrödinger equation with the Benjamin-Feir index (BFI) that, we know, is a measure of the modulational instability of the waves. From this point of view the value of this coefficient of the NLSE could be known from statistics. Thus the relationship between sea states and the mechanism of generation of rogue waves could be found out. Following the well-known Lie group theory researchers have been studying the Lie point symmetries of the NLSE: the scaling transformations, Galilean transformations and phase transformations. Basically these transformations turn the NLSE into a nonlinear ordinary differential equation called Duffing equation (also called eikonal equation). There are different ways to do this, but in most of them the independent variable that could be seen as a space variable is a kind of moving frame with the time incorporated in this way. The main aim of this work is to classify solutions of the Duffing equation (periodic and nonperiodic waves and also bounded and unbounded waves) bearing in mind that the coefficient of the nonlinear term in the NLSE is left unaltered in the process of the transformation.
Dynamics of proteins aggregation. I. Universal scaling in unbounded media
NASA Astrophysics Data System (ADS)
Zheng, Size; Javidpour, Leili; Shing, Katherine S.; Sahimi, Muhammad
2016-10-01
It is well understood that in some cases proteins do not fold correctly and, depending on their environment, even properly-folded proteins change their conformation spontaneously, taking on a misfolded state that leads to protein aggregation and formation of large aggregates. An important factor that contributes to the aggregation is the interactions between the misfolded proteins. Depending on the aggregation environment, the aggregates may take on various shapes forming larger structures, such as protein plaques that are often toxic. Their deposition in tissues is a major contributing factor to many neuro-degenerative diseases, such as Alzheimer's, Parkinson's, amyotrophic lateral sclerosis, and prion. This paper represents the first part in a series devoted to molecular simulation of protein aggregation. We use the PRIME, a meso-scale model of proteins, together with extensive discontinuous molecular dynamics simulation to study the aggregation process in an unbounded fluid system, as the first step toward MD simulation of the same phenomenon in crowded cellular environments. Various properties of the aggregates have been computed, including dynamic evolution of aggregate-size distribution, mean aggregate size, number of peptides that contribute to the formation of β sheets, number of various types of hydrogen bonds formed in the system, radius of gyration of the aggregates, and the aggregates' diffusivity. We show that many of such quantities follow dynamic scaling, similar to those for aggregation of colloidal clusters. In particular, at long times the mean aggregate size S(t) grows with time as, S(t) ˜ tz, where z is the dynamic exponent. To our knowledge, this is the first time that the qualitative similarity between aggregation of proteins and colloidal aggregates has been pointed out.
Observations of cometary nuclei
NASA Astrophysics Data System (ADS)
A'Hearn, M. F.
Attempts to observe cometary nuclei and to determine fundamental physical parameters relevant to the relationship between comets and asteroids are reviewed. It has been found that cometary nuclei, at least of periodic comets, are bigger and blacker than generally thought as recently as five years ago. Geometric albedos may be typically three percent and typical radii are probably of order 5 km. Nuclei of periodic comets are probably highly prolate unless they are both oblate and rotating about one of the major axes. P/Halley images provide convincing evidence of the existence of mantles discussed in many models. Numerous pieces of evidence suggest a connection between cometary nuclei and A-A asteroids of types D and C.
Machado, Gleyce Alves; Oliveira, Heliana Batista de; Gennari-Cardoso, Margareth Leitão; Mineo, José Roberto; Costa-Cruz, Julia Maria
2013-05-01
The aim of the present study was to analyse Taenia solium metacestode antigens that were derived from the unbound fraction of jacalin affinity chromatography and subsequent tert-octylphenoxy poly (oxyethylene) ethanol Triton X-114 (TX-114) partitioning in the diagnosis of human neurocysticercosis (NCC). Immunoassays were designed to detect T. solium-specific IgG antibodies by ELISA and immunoblot. Serum samples were collected from 132 individuals who were categorised as follows: 40 had NCC, 62 presented Taenia spp or other parasitic diseases and 30 were healthy individuals. The jacalin-unbound (J unbound ) fraction presented higher sensitivity and specificity rates than the jacalin-bound fraction and only this fraction was subjected to subsequent TX-114 partitioning, resulting in detergent (DJ unbound ) and aqueous (AJ unbound ) fractions. The ELISA sensitivity and specificity were 85% and 84.8% for J unbound , 92.5% and 93.5% for DJ unbound and 82.5% and 82.6% for AJ unbound . By immunoblot, the DJ unbound fraction showed 100% sensitivity and specificity and only serum samples from patients with NCC recognised the 50-70 kDa T. solium-specific components. We conclude that the DJ unbound fraction can serve as a useful tool for the differential immunodiagnosis of NCC by immunoblot.
Vezina, Heather E.; Ng, Chee M.; Vazquez, Delia M.; Barks, John D.; Bhatt-Mehta, Varsha
2014-01-01
Objective To determine the population pharmacokinetics of unbound hydrocortisone (HC) in critically ill neonates and infants receiving intravenous HC for treatment of vasopressor-resistant hypotension and to identify patient-specific sources of pharmacokinetic variability. Design Prospective observational cohort study. Setting Level 3 neonatal intensive care unit. Patients Sixty-two critically ill neonates and infants receiving intravenous HC as part of standard of care for the treatment of vasopressor-resistant hypotension: median gestational age 28 weeks (range, 23 to 41), median weight 1.2 kg (range, 0.5 to 4.4), 29 females. Interventions None. Measurements Unbound baseline cortisol and post-dose HC concentrations measured from blood samples being drawn for routine laboratory tests. Main Results A one compartment model best described the data. Allometric weight and postmenstrual age (PMA) were significant covariates on unbound HC clearance (CL) and volume of distribution (V). Final population estimates for CL, V, and baseline cortisol concentration were 20.2 L/h, 244 L, and 1.37 ng/mL, respectively. Using the median weight and PMA of our subjects (i.e. 1.2 kg and 28 weeks) in the final model, the typical unbound HC CL and V were 1.0 L/h and 4.2 L, respectively. The typical half-life for unbound HC was 2.9 hours. A sharp and continuous increase in unbound HC CL was observed at 35 weeks PMA. Conclusions We report the first pharmacokinetic data for unbound HC, the pharmacologically active moiety, in critically ill neonates and infants with vasopressor-resistant hypotension. Unbound HC CL increased with body weight and was faster in children with an older PMA. Unbound HC CL increased sharply at 35 weeks PMA and continued to mature thereafter. This study lays the groundwork for evaluating unbound HC exposure-response relationships and drawing definitive conclusions about the dosing of intravenous HC in critically-ill neonates and infants with vasopressor
Disappearance of Z=120 & 126 magicity and presence of hyper deformations in superheavy nuclei
NASA Astrophysics Data System (ADS)
Sharma, M. M.; Farhan, A. R.
2012-10-01
Conventional wisdom has it that Z=120 and especially Z=126 are predicted to be magic numbers for extreme superheavy nuclei. We have undertaken a study of structure of superheavy nuclei in the region of Z=120 to Z=126 within the framework of the deformed relativistic Hartree-Bogoliubov (DRHB) approach. Nuclei in this region entail a large density of states and are thus susceptible to a coupling to the continuum especially those which are close to being proton unbound. The DRHB approach which takes into account the coupling to the continuum is suitable for nuclei in the end of the periodic table. Additionally, the pairing in this approach is included within the Bogoliubov quasi-particle scheme, which takes into account the shell gap at the Fermi surface appropriately. Using the successful Lagrangian model NL-SV1 [1] based upon the vector self-coupling of φ-meson, it is shown that the perceived shell gaps at Z=120 and Z=126 disappear, thus making these proton numbers as non-magic. It is also shown that due to very large Coulomb force acting in these nuclei which are virtually at the end of the periodic table, stability to the nuclei in this region is brought about by extremely large elongated shapes with β2 ˜ 0.70-0.80. Consequences on formation of superheavy nuclei in this region will be discussed.
Asymptotic theory of lee waves in an unbounded atmosphere
NASA Astrophysics Data System (ADS)
Bois, P. A.
In the terrestrial atmosphere described as an unbounded medium with variable temperature, the equations of small Mach number airflows are written in the framework of an asymptotic Boussinesq's approximation. An equation is obtained which is a Helmholtz equation with slowly varying coefficients. This equation is then used to describe the stationary linearized flow over an obstacle of small height. It is shown under realistic conditions of the repartition of Scorer's parameter that the flow over the obstacle is divided in two regions: a lee wave system builds up in the lower layer while a progressive wave emerges in the upper layer. The two flows appear to be uncoupled in a first approximation, so that the classical representation of lee waves by confined flows is justified. Dans l'atmosphère terrestre décrite come un milieu non borné en altitude à température variable, on écrit l'équation des écoulements à faible nombre de Mach dans le cadre de l'approximation de Boussinesq. On obtient une équation de Helmholtz à coefficients lentement variables. Cette équation est utilisée pour décrire l'écoulement stationnaire linéarisé au dessus d'un obstacle de faible hauteur. On montre que dans des conditions de répartition du paramètre de Scorer qui sont réalistes, l'écoulement au dessus de l'obstacle se divise en deux régions: dans une couche inférieure s'établit un système d'ondes de relief, et dans la couche supérieure une onde progressive. Les deux écoulements apparaissent en première approximation comme découplés, ce qui justifie la représentation classique des ondes de relief par des écoulements confinés.
NASA Technical Reports Server (NTRS)
Malik, F. Bary
1993-01-01
The investigation indicates that nuclei with excitation energy of a few hundred MeV to BeV are more likely to radiate hot nuclear clusters than neutrons. These daughter clusters could, furthermore, de-excite emitting other hot nuclei, and the chain continues until these nuclei cool off sufficiently to evaporate primarily neutrons. A few GeV excited nuclei could radiate elementary particles preferentially over neutrons. Impact of space radiation with materials (for example, spacecraft) produces highly excited nuclei which cool down emitting electromagnetic and particle radiations. At a few MeV excitation energy, neutron emission becomes more dominant than gamma-ray emission and one often attributes the cooling to take place by successive neutron decay. However, a recent experiment studying the cooling process of 396 MeV excited Hg-190 casts some doubt on this thinking, and the purpose of this investigation is to explore the possibility of other types of nuclear emission which might out-compete with neutron evaporation.
The Scattering of Fast Nucleons from Nuclei
NASA Astrophysics Data System (ADS)
Kerman, A. K.; McManus, H.; Thaler, R. M.
2000-04-01
The formal theory of the scattering of high-energy nucleons by nuclei is developed in terms of the nucleon-nucleon scattering amplitude. The most important approximations necessary to make numerical calculation feasible are then examined. The optical model potential is derived on this basis and compared with the optical model parameters found from experiment. The elastic scattering and polarization of nucleons from light nuclei is predicted and compared with experiment. The effect of nuclear correlations is discussed. The polarization of inelastically scattered nucleons is discussed and predictions compared with experiments. To within the validity of the approximations the experimental data on the scattering of nucleons from nuclei at energies above ˜100 Mev appears to be consistent with the theory.
Electric dipole moment of light nuclei
NASA Astrophysics Data System (ADS)
Afnan, Iraj R.; Gibson, Benjamin F.
2010-07-01
We examine the sensitivity of the deuteron Electric Dipole Moment (EDM) to variation in the nucleon-nucleon interaction. In particular, we write the EDM as a sum of two terms, one depends on the target wave function, the second on intermediate multiple scattering states in the 3P1 channel. This second contribution is sensitive to off-shell behavior of the 3P1 amplitude.
Electroproduction of kaons on light nuclei
B. Zeidman; D. Abbott; A. Ahmidouch; P. Ambrozewicz; C. S. Armstrong; J. Arrington; R. Asaturyan; K. Assamagan; S. Avery; K. Bailey; O. K. Baker; S. Beedoe; H. Bitao; H. Breuer; D. S. Brown; R. Carlini; J. Cha; N. Chant; E. Christy; A. Cochran; L. Cole; G. Collins; C. Cothran; J. Crowder; W. J. Cummings; S. Danagoulian; F. Dohrmann; F. Duncan; J. Dunne; D. Dutta; T. Eden; M. Elaasar; R. Ent; L. Ewell; H. Fenker; H. T. Fortune; Y. Fujii; L. Gan; H. Gao; K. Garrow; D. F. Geesaman; P. Gueye; K. Gustafsson; K. Hafidi; J. O. Hansen; W. Hinton; H. E. Jackson; H. Juengst; C. Keppel; A. Klein; D. Koltenuk; Y. Liang; J. H. Liu; A. Lung; D. Mack; R. Madey; P. Markowitz; C. J. Martoff; D. Meekins; J. Mitchell; T. Miyoshi; H. Mkrtchyan; R. Mohring; S. K. Mtingwa; B. Mueller; T. G. O'Neill; G. Niculescu; I. Niculescu; D. Potterveld; J. W. Price; B. A. Raue; P. E. Reimer; J. Reinhold; J. Roche; P. Roos; M. Sarsour; Y. Sato; G. Savage; R. Sawafta; J. P. Schiffer; R. E. Segel; A. Semenov; S. Stepanyan; V. Tadevosian; S. Tajima; L. Tang; B. Terburg; A. Uzzle; S. Wood; H. Yamaguchi; C. Yan; L. Yuan; M. Zeier; B. Zihlmann
2001-08-13
The A(e,eiK+)YX reaction on H, D, {sup 3}He, and {sup 4}He was investigated in Hall C at CEBAF. Data were obtained for Q{sup 2} {approx} 0.35 and 0.5 GeV{sup 2} at 3.245 GeV. The missing mass spectra for both H and D are fitted with Monte-Carlo simulations incorporating peaks corresponding to Lambda production on the proton and Sigma production on both the proton and neutron. For D, the cross section ratio Sigma{sup 0}/Sigma{sup -} {approx} 2, and excess yield close to the thresholds for Lambda and Sigma production can be attributed to final-state interactions; models are compared to the data. The analysis of the data for the He targets is in a more preliminary state with broader quasi-free peaks resulting from the higher Fermi momenta. Evidence for bound Lambda-hypernuclear states is seen and other structure may be present.
Clusters and halos in light nuclei
NASA Astrophysics Data System (ADS)
Neff, Thomas
2012-12-01
The fermionic molecular dynamics approach uses Gaussian wave packets as single-particle basis states. Many-body basis states are Slater determinants projected on parity, angular momentum and total linear momentum. The wave-packet basis is very flexible - FMD contains harmonic oscillator shell model and Brink-type cluster states as special cases. The parameters of the wave packets are obtained by variation. A realistic effective interaction derived from the Argonne V18 interaction by means of the unitary correlation operator method is employed. We discuss the fully microscopic calculation of the 3He(α, γ)7Be capture reaction within the FMD approach. The model space contains frozen cluster configurations at large distances and polarized configurations in the interaction region. The polarized configurations are essential for a successful description of the 7Be bound state properties and for the S- and D-wave scattering states. The calculated cross section agrees well with recent measurements regarding both the absolute normalization and the energy dependence. We also discuss the structure of the cluster states, including the famous Hoyle state, in 12C. From the two-body densities we conclude that the Hoyle state has a spatially extended triangular α-cluster structure, whereas the third 0+ state features a chain-like obtuse triangle structure. We also calculate the NħΩ decomposition of our wave functions to illuminate the challenges of no-core shell model calculations for these cluster states.
Electroproduction of Kaons on light nuclei.
Zeidman, B.; Abbott, D.; Ahmidouch, A.; Ambrozewicz, P.; Armstrong, C. S.; Arrington, J.; Bailey, K.; Cummings, W. J.; Dohrmann, F.; Gao, H.; Geesaman, D. F.; Hafidi, K.; Hansen, J. O.; Jackson, H. E.; Mueller, B.; O'Neill, T. G.; Potterveld, D.; Reimer, P. E.; Reinhold, J.; Schiffer, J. P.
2000-12-07
The A(e,e{prime}K{sup +})YX reaction on H, D, {sup 3}He, and {sup 4}He was investigated in Hall C at CEBAF. Data were obtained for Q{sup 2} {approx} 0.35 and 0.5 GeV{sup 2} at 3.245 GeV. The missing mass spectra for both H and D are fitted with Monte-Carlo simulations incorporating peaks corresponding to {Lambda} production on the proton and {Sigma} production on both the proton and neutron. For D, the cross section ratio {Sigma}{sup 0}/{Sigma}{sup {minus}} {approx} 2, and excess yield close to the thresholds for {Lambda} and {Sigma} production can be attributed to final-state interactions that are compared to the data. The analysis of the data for the He targets is in a more preliminary state with broader quasi-free peaks resulting from the higher Fermi momenta. Evidence for bound {Lambda}-hypernuclear states is seen and other structure may be present.
Electric dipole moment of light nuclei
Gibson, Benjamin; Afnan, I R
2010-01-01
We examine the sensitivity of the deuteron Electric Dipole Moment (EDM) to variation in the nucleon-nucleon interaction. In particular, we write the EDM as a sum of two terms, one depends on the target wave function, the second on intermediate multiple scattering states in the {sup 3}P{sub 1} channel. This second contribution is sensitive to off-shell behavior of the {sup 3}P{sub 1} amplitude.
NASA Astrophysics Data System (ADS)
Hamilton, J. H.; Hofmann, S.; Oganessian, Y. T.
2013-10-01
We describe the discoveries of new superheavy nuclei (a) with Z=107-112 produced in cold fusion reactions between 208Pb and 209Bi and beams of A > 50 and (b) with Z=113-118 in hot fusion reactions between actinide nuclei and 48Ca. We also discuss the facilities used in these measurements. We compare the behavior of the β-decay energies and half-lives, spontaneous fission half-lives, cross sections, and excitation functions with expectations from theoretical calculations. Finally, we outline future research directions, including studies of the detailed properties of nuclei synthesized at higher yields, searches for new elements with Z=119 and 120, and developments of new facilities.
NASA Astrophysics Data System (ADS)
Dale, J. E.; Ercolano, B.; Bonnell, I. A.
2013-03-01
We extend our previous smoothed particle hydrodynamics parameter study of the effects of photoionization from O-stars on star-forming clouds to include initially unbound clouds. We generate a set of model clouds in the mass range 104-106 M⊙ with initial virial ratios Ekin/Epot = 2.3, allow them to form stars and study the impact of the photoionizing radiation produced by the massive stars. We find that, on the 3 Myr time-scale before supernovae are expected to begin detonating, the fraction of mass expelled by ionizing feedback is a very strong function of the cloud escape velocities. High-mass clouds are largely unaffected dynamically, while low-mass clouds have large fractions of their gas reserves expelled on this time-scale. However, the fractions of stellar mass unbound are modest and significant portions of the unbound stars are so only because the clouds themselves are initially partially unbound. We find that ionization is much more able to create well-cleared bubbles in the unbound clouds, owing to their intrinsic expansion, but that the presence of such bubbles does not necessarily indicate that a given cloud has been strongly influenced by feedback. We also find, in common with the bound clouds from our earlier work, that many of the systems simulated here are highly porous to photons and supernova ejecta, and that most of them will likely survive their first supernova explosions.
Flavanol binding of nuclei from tree species.
Feucht, W; Treutter, D; Polster, J
2004-01-01
Light microscopy was used to examine the nuclei of five tree species with respect to the presence of flavanols. Flavanols develop a blue colouration in the presence of a special p-dimethylaminocinnamaldehyde (DMACA) reagent that enables those nuclei loaded with flavanols to be recognized. Staining of the nuclei was most pronounced in both Tsuga canadensis and Taxus baccata, variable in Metasequoia glyptostroboides, faint in Coffea arabica and minimal in Prunus avium. HPLC analysis showed that the five species contained substantial amounts of different flavanols such as catechin, epicatechin and proanthocyanidins. Quantitatively, total flavanols were quite different among the species. The nuclei themselves, as studied in Tsuga seed wings, were found to contain mainly catechin, much lower amounts of epicatechin and traces of proanthocyanidins. Blue-coloured nuclei located centrally in small cells were often found to maximally occupy up to 90% of a cell's radius, and the surrounding small rim of cytoplasm was visibly free of flavanols. A survey of 34 gymnosperm and angiosperm species indicated that the first group has much higher nuclear binding capacities for flavanols than the second group.
Disintegration of comet nuclei
NASA Astrophysics Data System (ADS)
Ksanfomality, Leonid V.
2012-02-01
The breaking up of comets into separate pieces, each with its own tail, was seen many times by astronomers of the past. The phenomenon was in sharp contrast to the idea of the eternal and unchangeable celestial firmament and was commonly believed to be an omen of impending disaster, especially for comets with tails stretching across half the sky. It is only now that we have efficient enough space exploration tools to see comet nuclei and even - in the particular case of small comet Hartley-2 in 2010 - to watch their disintegration stage. There are also other suspected candidates for disintegration in the vast family of comet nuclei and other Solar System bodies.
Toward concordance of Ex and J^{π} values for proton unbound 31S states
NASA Astrophysics Data System (ADS)
Parikh, A.; Wrede, C.; Fry, C.
2016-09-01
Nucleosynthesis in classical novae on oxygen-neon white dwarfs is sensitive to the poorly constrained thermonuclear rate of the 30 P( p,γ)31 S reaction. In order to improve this situation, a variety of experiments have been performed over the past decade to determine the properties of proton unbound 31S levels up to an excitation energy of ≈ 6.7 MeV. Inconsistencies in the energies and J^{π} values for these levels have made it difficult to produce a useful 30 P( p, γ)31 S reaction rate based on experimental information. In the present work, we revisit a subset of published data on the structure of 31S in order to shed light on these problems. First, we present an alternative calibration of 31 P(3 He, t)31 S spectra using newly available high-precision data in order to address discrepant 31S excitation energies. Second, we apply a similar method to a recently acquired 32 S( d, t)31 S spectrum. Third, for a different 31 P(3 He, t)31 S experiment in which angular distributions were acquired, we present alternative fits to the experimental data in order to address discrepant 31S J^{π} values. Finally, we compare the J^{π} values from 31 P(3 He, t)31 S to those reported from in beam γ-ray spectroscopy experiments in order to search for potential resolutions to the inconsistencies. Overall, viable new solutions to some of the problems emerge, but other problems persist.
Audin, L.
1994-12-31
EPAct covers a vast territory beyond lighting and, like all legislation, also contains numerous {open_quotes}favors,{close_quotes} compromises, and even some sleight-of-hand. Tucked away under Title XIX, for example, is an increase from 20% to 28% tax on gambling winnings, effective January 1, 1993 - apparently as a way to help pay for new spending listed elsewhere in the bill. Overall, it is a landmark piece of legislation, about a decade overdue. It remains to be seen how the Federal Government will enforce upgrading of state (or even their own) energy codes. There is no mention of funding for {open_quotes}energy police{close_quotes} in EPAct. Merely creating such a national standard, however, provides a target for those who sincerely wish to create an energy-efficient future.
NASA Astrophysics Data System (ADS)
Hamilton, J. H.; Maruhn, J. A.
1986-07-01
From the study of nuclei with abundances of neutrons and protons (N numbers and Z numbers) quite different from those found in nature, it has been possible to gain new views of motions and structures within nuclear matter. Based on the spherical shell model of the nucleus proposed by Mayer and Jensen in 1949 and the collective model of nuclear deformation proposed in 1952 by Bohr and Mottelson, it has come to be possible to decide what shape or shapes a nucleus must have for a given set of N and Z numbers. It turns out that not only spherical nuclei are possible but also prolate and oblate spheroids (football and discus shaped), triaxial (like a partially deflated football), and even pear- or peanut-shaped. A significant experimental tool in such studies is the ISOL or Isotope-Separator, On-Line, which makes possible the construction of energy level diagrams from the study of exotic nuclei created when particles from accelerators strike various kinds of foil. The significance of magic numbers and super-magic numbers (particular combinations of N and Z) for the stability of various exotic nuclei is considered. International facilities engaged in such studies are noted.
Physics with Polarized Nuclei.
ERIC Educational Resources Information Center
Thompson, William J.; Clegg, Thomas B.
1979-01-01
Discusses recent advances in polarization techniques, specifically those dealing with polarization of atomic nuclei, and how polarized beams and targets are produced. These techniques have greatly increased the scope of possible studies, and provided the tools for testing fundamental symmetries and the spin dependence of nuclear forces. (GA)
Chen, Haoran; Sun, Yuanfei; Shen, Yang
2017-03-01
Predicting protein conformational changes from unbound structures or even homology models to bound structures remains a critical challenge for protein docking. Here we present a study directly addressing the challenge by reducing the dimensionality and narrowing the range of the corresponding conformational space. The study builds on cNMA-our new framework of partner- and contact-specific normal mode analysis that exploits encounter complexes and considers both intrinsic and induced flexibility. First, we established over a CAPRI (Critical Assessment of PRedicted Interactions) target set that the direction of conformational changes from unbound structures and homology models can be reproduced to a great extent by a small set of cNMA modes. In particular, homology-to-bound interface root-mean-square deviation (iRMSD) can be reduced by 40% on average with the slowest 30 modes. Second, we developed novel and interpretable features from cNMA and used various machine learning approaches to predict the extent of conformational changes. The models learned from a set of unbound-to-bound conformational changes could predict the actual extent of iRMSD with errors around 0.6 Å for unbound proteins in a held-out benchmark subset, around 0.8 Å for unbound proteins in the CAPRI set, and around 1 Å even for homology models in the CAPRI set. Our results shed new insights into origins of conformational differences between homology models and bound structures and provide new support for the low-dimensionality of conformational adjustment during protein associations. The results also provide new tools for ensemble generation and conformational sampling in unbound and homology docking. Proteins 2017; 85:544-556. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.
Improvement of Bearing Capacity in Recycled Aggregates Suitable for Use as Unbound Road Sub-Base
Garach, Laura; López, Mónica; Agrela, Francisco; Ordóñez, Javier; Alegre, Javier; Moya, José Antonio
2015-01-01
Recycled concrete aggregates and mixed recycled aggregates are specified as types of aggregates with lower densities, higher water absorption capacities, and lower mechanical strength than natural aggregates. In this paper, the mechanical behaviour and microstructural properties of natural aggregates, recycled concrete aggregates and mixed recycled aggregates were compared. Different specimens of unbound recycled mixtures demonstrated increased resistance properties. The formation of new cement hydrated particles was observed, and pozzolanic reactions were discovered by electronon microscopy in these novel materials. The properties of recycled concrete aggregates and mixed recycled aggregates suggest that these recycled materials can be used in unbound road layers to improve their mechanical behaviour in the long term. PMID:28793747
Spectral dimension and Bohr's formula for Schrödinger operators on unbounded fractal spaces
NASA Astrophysics Data System (ADS)
Chen, Joe P.; Molchanov, Stanislav; Teplyaev, Alexander
2015-09-01
We establish an asymptotic formula for the eigenvalue counting function of the Schrödinger operator -{{Δ }}+V for some unbounded potentials V on several types of unbounded fractal spaces. We give sufficient conditions for Bohr’s formula to hold on metric measure spaces which admit a cellular decomposition, and then verify these conditions for fractafolds and fractal fields based on nested fractals. In particular, we partially answer a question of Fan, Khandker, and Strichartz regarding the spectral asymptotics of the harmonic oscillator potential on the infinite blow-up of a Sierpinski gasket.
Improvement of Bearing Capacity in Recycled Aggregates Suitable for Use as Unbound Road Sub-Base.
Garach, Laura; López, Mónica; Agrela, Francisco; Ordóñez, Javier; Alegre, Javier; Moya, José Antonio
2015-12-16
Recycled concrete aggregates and mixed recycled aggregates are specified as types of aggregates with lower densities, higher water absorption capacities, and lower mechanical strength than natural aggregates. In this paper, the mechanical behaviour and microstructural properties of natural aggregates, recycled concrete aggregates and mixed recycled aggregates were compared. Different specimens of unbound recycled mixtures demonstrated increased resistance properties. The formation of new cement hydrated particles was observed, and pozzolanic reactions were discovered by electronon microscopy in these novel materials. The properties of recycled concrete aggregates and mixed recycled aggregates suggest that these recycled materials can be used in unbound road layers to improve their mechanical behaviour in the long term.
Gupta, R.K.; Singh, S.; Muenzenberg, G.; Scheid, W. ||
1995-05-01
Nuclei at the neutron-drip line are studied. The light neutron-halo nuclei are found to play an important role for both cold fusion reactions and exotic cluster decay studies of heavy nuclei at the neutron-drip line. For cold fusion reactions, beams of neutron-halo nuclei are shown to occur as natural extensions of the conventional lighter beams but with the corresponding target nuclei as the heavy neutron-rich radioactive nuclei. Thus, in synthesizing the various isotopes of a neutron-rich cool compound nucleus, both the target and projectile nuclei have to be richer in neutrons, with their proton numbers remaining the same. On the other hand, neutron-halo (cluster) decays are favored for a relatively less neutron-rich parent nucleus. Possible consequences of this work for the shell structure effects in neutron-rich heavy nuclei are also pointed out. This follows from the fact that the so far observed phenomena of both cold fusion and cluster radioactivity are associated with closed or nearly closed shell nuclei. Calculations are made for {sup 274,288}104, using the quantum mechanical fragmentation theory for cold fusion reaction studies and a performed cluster model for cluster decay studies.
Fusion and Breakup of Weakly Bound Nuclei
Gomes, P. R. S.; Lubian, J.; Padron, I.; Crema, E.; Chamon, L. C.; Hussein, M. S.; Canto, L. F.
2006-08-14
We discuss the influence of the breakup process of weakly bound nuclei on the fusion cross section. The complete fusion for heavy targets is found to be suppressed due to the incomplete fusion following the breakup, whereas this effect is negligible for light targets. The total fusion cross sections for stable projectiles are not affected by the breakup process, whereas it is suppressed for halo projectiles. The non capture breakup is the dominant process at sub-barrier energies.
Invariant-Mass Spectroscopy of Extremely Neutron-Rich Nuclei with SAMURAI at RIBF
NASA Astrophysics Data System (ADS)
Kondo, Yosuke; Nakamura, Takashi; Achouri, N. Lynda; Aumann, Thomas; Baba, Hidetada; Delaunay, Franck; Doornenbal, Pieter; Fukuda, Naoki; Gibelin, Julien; Hwang, Jongwon; Inabe, Naohito; Isobe, Tadaaki; Kameda, Daisuke; Kanno, Daiki; Kim, Sunji; Kobayashi, Nobuyuki; Kobayashi, Toshio; Kubo, Toshiyuki; Leblond, Sylvain; Lee, Jenny; Marqués, F. Miguel; Minakata, Ryogo; Motobayashi, Tohru; Murai, Daichi; Murakami, Tetsuya; Muto, Kotomi; Nakashima, Tomohiro; Nakatsuka, Noritsugu; Navin, Alahari; Nishi, Seijiro; Ogoshi, Shun; Orr, Nigel A.; Otsu, Hideaki; Sato, Hiromi; Satou, Yoshiteru; Shimizu, Yohei; Suzuki, Hiroshi; Takahashi, Kento; Takeda, Hiroyuki; Takeuchi, Satoshi; Tanaka, Ryuki; Togano, Yasuhiro; Tuff, Adam G.; Vandebrouck, Marine; Yoneda, Ken-ichiro
A first experimental campaign for three physics programs using a spectrometer SAMURAI, which is newly constructed at RIBF at RIKEN, was performed in May 2012. In this campaign, the unbound nuclei 25O and 26O produced by one-proton removal reactions at ˜200 MeV/nucleon were investigated by means of invariant mass method. High statistics data compared with previous experiments could be obtained together with good particle identification resolution for outgoing heavy ion. Preliminary results show high performance of the SAMURAI spectrometer combined with high intense RI beams provided by RIBF.
α cluster structures in unbound states in 19Ne
NASA Astrophysics Data System (ADS)
Otani, Reiji; Iwasaki, Masataka; Ito, Makoto
2016-06-01
Cluster structures in 19Ne are studied by the microscopic and macroscopic cluster models. In the microscopic calculation, the coupled-channels problem of (3He+16O) + (α+15O) is solved, and the adiabatic energy surfaces, which are the series of the energy eigenvalues as a function of the He-O distance, are investigated. In the adiabatic energy curves, the several local minima are generated in the spatial region of the small core distance, where the neutron hole inside of the He or O nucleus is strongly coupled to the residual nuclei. The energy spectra, which are constructed from the strong coupling states, nicely reproduce the the low-lying energy levels in the 19Ne nucleus. In the macroscopic approach, the α + 15O potential is evaluated from the elastic scattering of the α + 15N system, and the resonant levels of the α + 15O system are calculated under the absorbing boundary condition. The potential model predicts the existence of the resonances above the α threshold, which has a weak-coupling scheme of the α particle and one hole inside of the 16O nucleus. The extended microscopic calculations of (3He+16O) + (α+15O) + (5He+14O) are performed in order to see the coupling effect of the 5p-2h configuration, which corresponds to the shell model limit of the 5He + 14O cluster configuration. The extended calculation suggests that the 5He + 14O configuration plays an important role on the formation of the 3/2+ resonance at 0.5 MeV with respect to the α threshold.
Energetic Nuclei, Superdensity and Biomedicine
ERIC Educational Resources Information Center
Baldin, A. M.
1977-01-01
High-energy, relativistic nuclei were first observed in cosmic rays. Studing these nuclei has provided an opportunity for analyzing the composition of cosmic rays and for experimentally verifying principles governing the behavior of nuclear matter at high and super-high temperatures. Medical research using accelerated nuclei is suggested.…
Energetic Nuclei, Superdensity and Biomedicine
ERIC Educational Resources Information Center
Baldin, A. M.
1977-01-01
High-energy, relativistic nuclei were first observed in cosmic rays. Studing these nuclei has provided an opportunity for analyzing the composition of cosmic rays and for experimentally verifying principles governing the behavior of nuclear matter at high and super-high temperatures. Medical research using accelerated nuclei is suggested.…
Chen, J; Cottrell, M; Trezza, CR; Prince, HMA; Sykes, C; Torrice, C; White, N; Malone, S; Wang, R; Patterson, KB; Sharpless, NE; Forrest, A
2016-01-01
Unbound drug is the pharmacodynamically relevant concentration. This study aimed to determine if chronologic age or markers of biologic aging, such as the frailty phenotype and p16INK4a gene expression, altered unbound pharmacokinetics (PKs) of efavirenz (EFV) and atazanavir/ritonavir (ATV/RTV). Sixty human immunodeficiency virus (HIV)‐infected participants receiving EFV and 31 receiving ATV/RTV provided 1 to 11 samples to quantify total and unbound plasma concentrations. Population PK models with total and unbound concentrations simultaneously described are developed for each drug. The unbound fractions for EFV, ATV, and RTV are 0.65%, 5.67%, and 0.63%, respectively. Covariate analysis suggests RTV unbound PK is sensitive to body size; unbound fraction of RTV is 34% lower with body mass index (BMI) above 30 kg/m2. No alterations in drug clearance or unbound fraction with age, frailty, or p16INK4a expression were observed. Assessing functional and physiologic aging markers to inform potential PK changes is necessary to determine if drug/dosing changes are warranted in the aging population. PMID:28032946
Collective Clusterization in Nuclei and Excited Compound Systems: The Dynamical Cluster-Decay Model
NASA Astrophysics Data System (ADS)
Gupta, Raj K.
Clustering is a general feature of light, N = Z, α-like stable nuclei for both the ground and (intrinsic) excited states. This phenomenon is observed in spontaneous decays of heavy radioactive nuclei, and seems to play an important role in the decay of excited compound systems formed in heavy ion reactions. It is also shown to be present in exotic light-halo, super-heavy and super-superheavy nuclei.
NASA Astrophysics Data System (ADS)
Neff, Thomas; Feldmeier, Hans; Roth, Robert
2006-10-01
In the Fermionic Molecular Dynamics (FMD) model the nuclear many-body system is described using Slater determinants with Gaussian wave-packets as single-particle states. The flexibility of the FMD wave functions allows for a consistent description of shell model like structures, deformed states, cluster structures as well as halos. An effective interaction derived from the realistic Argonne V18 interaction using the Unitary Correlation Operator Method is used for all nuclei. Results for nuclei in the p-shell will be presented. Halo features are present in the Helium isotopes, cluster structures are studied in Beryllium and Carbon isotopes. The interplay between shell structure and cluster structures in the ground and the Hoyle state in ^12C will be discussed.
21 CFR 862.1113 - Bilirubin (total and unbound) in the neonate test system.
Code of Federal Regulations, 2010 CFR
2010-04-01
... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Bilirubin (total and unbound) in the neonate test system. 862.1113 Section 862.1113 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical...
ERIC Educational Resources Information Center
Sullivan, Heather I.
2010-01-01
While nature is often claimed to be a space of harmonized balance or an antidote to the chaos of the modern world, we need a more grounded assessment of nature as endlessly changing and much less predictable than we like to assume. In this essay, I explore Karen Traviss' provocative exploration of unbalanced nature and unbounded bodies in her…
Chandrasekhar equations for infinite dimensional systems. Part 2: Unbounded input and output case
NASA Technical Reports Server (NTRS)
Ito, Kazufumi; Powers, Robert K.
1987-01-01
A set of equations known as Chandrasekhar equations arising in the linear quadratic optimal control problem is considered. In this paper, we consider the linear time-invariant system defined in Hilbert spaces involving unbounded input and output operators. For a general class of such systems, the Chandrasekhar equations are derived and the existence, uniqueness, and regularity of the results of their solutions established.
NASA Astrophysics Data System (ADS)
Hu, Yangzi; Wu, Fuke; Huang, Chengming
2012-02-01
Without the linear growth condition on the drift coefficient, this article examines the existence and uniqueness of global solutions of a class of neutral stochastic differential equations with unbounded delay and their asymptotic stabilities with general decay rate. To illustrate the application of our results, this article gives a two-dimensional system as an example.
ERIC Educational Resources Information Center
Sullivan, Heather I.
2010-01-01
While nature is often claimed to be a space of harmonized balance or an antidote to the chaos of the modern world, we need a more grounded assessment of nature as endlessly changing and much less predictable than we like to assume. In this essay, I explore Karen Traviss' provocative exploration of unbalanced nature and unbounded bodies in her…
An Exploration of the Validity of the Unbounded Write-In Scale.
ERIC Educational Resources Information Center
Stapleton, Laura M.; Edmonds, Meaghan
An exploratory reliability and validity study was conducted of a relatively new response scale developed in the marketing field. Unlike many Likert-type scales, the "unbounded write-in" scale is claimed to produce distributions that more closely approximate normal distributions. This type of scale has been used in large-scale marketing studies.…
Reducibility of 1-d Schrödinger Equation with Time Quasiperiodic Unbounded Perturbations, II
NASA Astrophysics Data System (ADS)
Bambusi, D.
2017-01-01
We study the Schrödinger equation on R with a potential behaving as {x^{2l}} at infinity, {l in [1, + ∞)} and with a small time quasiperiodic perturbation. We prove that if the perturbation belongs to a class of unbounded symbols including smooth potentials and magnetic type terms with controlled growth at infinity, then the system is reducible.
Reducibility of 1-d Schrödinger Equation with Time Quasiperiodic Unbounded Perturbations, II
NASA Astrophysics Data System (ADS)
Bambusi, D.
2017-07-01
We study the Schrödinger equation on R with a potential behaving as {x^{2l}} at infinity, {l \\in [1, + ∞)} and with a small time quasiperiodic perturbation. We prove that if the perturbation belongs to a class of unbounded symbols including smooth potentials and magnetic type terms with controlled growth at infinity, then the system is reducible.
ERIC Educational Resources Information Center
Donovan, Phillip Raymond
2009-01-01
This study focuses on the analysis of the behavior of unbound aggregates to offset wheel loads. Test data from full-scale aircraft gear loading conducted at the National Airport Pavement Test Facility (NAPTF) by the Federal Aviation Administration (FAA) are used to investigate the effects of wander (offset loads) on the deformation behavior of…
ERIC Educational Resources Information Center
Donovan, Phillip Raymond
2009-01-01
This study focuses on the analysis of the behavior of unbound aggregates to offset wheel loads. Test data from full-scale aircraft gear loading conducted at the National Airport Pavement Test Facility (NAPTF) by the Federal Aviation Administration (FAA) are used to investigate the effects of wander (offset loads) on the deformation behavior of…
Comments on "A modified reachability tree approach to analysis of unbounded Petri nets".
Ru, Yu; Wu, Weimin; Hadjicostis, Christoforos N
2006-10-01
The above paper introduced the construction of a modified reachability tree (MRT) for (unbounded) Petri nets and its application to reachability, liveness, and deadlock analysis. This note shows via a counterexample that some of the MRT properties claimed in the above paper are incorrect.
NASA Technical Reports Server (NTRS)
Allaire, P. E.; Branagan, L. A.; Kocur, J. A.
1982-01-01
An unbounded eccentric centrifugal impeller with an infinite number of log spiral blades undergoing synchronous whirling in an incompressible fluid is considered. The forces acting on it due to coriolis forces, centripetal forces, changes in linear momentum, changes in pressure due to rotating and changes in pressure due to changes in linear momentum are evaluated.
The intergalactic propagation of ultrahigh energy cosmic ray nuclei
Hooper, Dan; Sarkar, Subir; Taylor, Andrew M.; /Oxford U.
2006-08-01
We investigate the propagation of ultra-high energy cosmic ray nuclei (A = 1-56) from cosmologically distant sources through the cosmic radiation backgrounds. Various models for the injected composition and spectrum and of the cosmic infrared background are studied using updated photodisintegration cross-sections. The observational data on the spectrum and the composition of ultra-high energy cosmic rays are jointly consistent with a model where all of the injected primary cosmic rays are iron nuclei (or a mixture of heavy and light nuclei).
Relativistic mean field calculations in neutron-rich nuclei
Gangopadhyay, G.; Bhattacharya, Madhubrata; Roy, Subinit
2014-08-14
Relativistic mean field calculations have been employed to study neutron rich nuclei. The Lagrange's equations have been solved in the co-ordinate space. The effect of the continuum has been effectively taken into account through the method of resonant continuum. It is found that BCS approximation performs as well as a more involved Relativistic Continuum Hartree Bogoliubov approach. Calculations reveal the possibility of modification of magic numbers in neutron rich nuclei. Calculation for low energy proton scattering cross sections shows that the present approach reproduces the density in very light neutron rich nuclei.
Assessing the risk of drug-induced cholestasis using unbound intrahepatic concentrations.
Riede, Julia; Poller, Birk; Huwyler, Jorg; Camenisch, Gian
2017-03-02
Inhibition of the bile salt export pump (BSEP) has been recognized as a key factor in the development of drug-induced cholestasis (DIC). The risk of DIC in human has previously been assessed using in vitro BSEP inhibition data (IC50) and unbound systemic drug exposure under assumption of the "free drug hypothesis". This concept, however, is unlikely valid as unbound intrahepatic drug concentrations are affected by active transport and metabolism. To investigate this hypothesis we experimentally determined the in vitro liver-to-blood partition coefficients (Kp,uu) for 18 drug compounds using the hepatic Extended Clearance Model (ECM). In vitro-in vivo translatability of Kp,uu values was verified for a subset of compounds in rat. Consequently, unbound intrahepatic concentrations were calculated from clinical exposure (systemic and hepatic inlet) and measured Kp,uu data. Using these values, corresponding safety margins against BSEP IC50 values were determined and compared to the clinical incidence of DIC. Depending on the ECM class of a drug, in vitro Kp,uu values deviated up to 14-fold from unity and unbound intrahepatic concentrations were affected accordingly. The use of in vitro Kp,uu-based safety margins allowed to separate clinical cholestasis frequency into three classes (no cholestasis, cholestasis in ≤ 2%, and in > 2% of subjects) for 17 out of 18 compounds. This assessment was significantly superior compared to using unbound extracellular concentrations as a surrogate for intrahepatic concentrations. Furthermore, the assessment of Kpuu according to ECM provides useful guidance for the quantitative evaluation of genetic and physiological risk factors for the development of cholestasis.
Measurement of unbound bilirubin by the peroxidase test using Zone Fluidics.
Ahlfors, Charles E; Marshall, Graham D; Wolcott, Duane K; Olson, Don C; Van Overmeire, Bart
2006-03-01
Measuring plasma unbound bilirubin concentration by the peroxidase test is useful in the management of jaundiced newborns. However, the commercially available peroxidase technology is manual, and the unbound bilirubin may be seriously underestimated at the 42-fold sample dilution and single peroxidase concentration used. We investigated improving the test by adapting it to Zone Fluidics, which is a system for automating reactant handling that requires small sample volumes and dilution. A computer-directed Zone Fluidics system was constructed using small diameter tubing to connect in series a water-surfactant reservoir, a bi-directional pump, a multiport selection valve to which peroxidase test reactants (45 mul of sample) are attached with one port open to air, and a spectrophotometer flow cell. Test reactants and air are sequentially aspirated through the valve into the tubing connecting the pump and valve to form a reactant "zone" surrounded by air. The zone is advanced to the spectrophotometer flow cell where total and unbound bilirubin are determined (37 degrees C) from the absorbance at 460 nm at a 2-fold sample dilution and 4 peroxidase concentrations. Imprecision was assessed in artificial controls and newborn plasma. Plasma results were compared with those obtained using the commercial method. The CV for unbound bilirubin in the various controls ranged from 11% to 38% (within day) and 12% to 27% (between days). Triplicate CV measurements for newborn plasma measurements ranged from 0.6% to 31% (mean 11%, n=47). Mean unbound bilirubin by Zone Fluidics was 5-fold higher than that by the commercial method. Zone Fluidics can be used to automate the peroxidase test and overcome many of the limitations of the commercially available peroxidase technology.
Social Cognition Unbound: Insights Into Anthropomorphism and Dehumanization
Waytz, Adam; Epley, Nicholas; Cacioppo, John T.
2014-01-01
People conceive of wrathful gods, fickle computers, and selfish genes, attributing human characteristics to a variety of supernatural, technological, and biological agents. This tendency to anthropomorphize nonhuman agents figures prominently in domains ranging from religion to marketing to computer science. Perceiving an agent to be humanlike has important implications for whether the agent is capable of social influence, accountable for its actions, and worthy of moral care and consideration. Three primary factors—elicited agent knowledge, sociality motivation, and effectance motivation—appear to account for a significant amount of variability in anthropomorphism. Identifying these factors that lead people to see nonhuman agents as humanlike also sheds light on the inverse process of dehumanization, whereby people treat human agents as animals or objects. Understanding anthropomorphism can contribute to a more expansive view of social cognition that applies social psychological theory to a wide variety of both human and nonhuman agents. PMID:24839358
Social Cognition Unbound: Insights Into Anthropomorphism and Dehumanization.
Waytz, Adam; Epley, Nicholas; Cacioppo, John T
2010-02-01
People conceive of wrathful gods, fickle computers, and selfish genes, attributing human characteristics to a variety of supernatural, technological, and biological agents. This tendency to anthropomorphize nonhuman agents figures prominently in domains ranging from religion to marketing to computer science. Perceiving an agent to be humanlike has important implications for whether the agent is capable of social influence, accountable for its actions, and worthy of moral care and consideration. Three primary factors-elicited agent knowledge, sociality motivation, and effectance motivation-appear to account for a significant amount of variability in anthropomorphism. Identifying these factors that lead people to see nonhuman agents as humanlike also sheds light on the inverse process of dehumanization, whereby people treat human agents as animals or objects. Understanding anthropomorphism can contribute to a more expansive view of social cognition that applies social psychological theory to a wide variety of both human and nonhuman agents.
NASA Technical Reports Server (NTRS)
Rahe, J.; Vanysek, V.; Weissman, P. R.
1994-01-01
Active long- and short-period comets contribute about 20 to 30 % of the major impactors on the Earth. Cometary nuclei are irregular bodies, typically a few to ten kilometers in diameter, with masses in the range 10(sup 15) to 10(sup 18) g. The nuclei are composed of an intimate mixture of volatile ices, mostly water ice and hydrocarbon and silicate grains. The composition is the closest to solar composition of any known bodies in the solar system. The nuclei appear to be weakly bonded agglomerations of smaller icy planetesimals, and material strengths estimated from observed tidal disruption events are fairly low, typically 10(sup 2) to 10(sup 4) N m(sup -2). Density estimates range between 0.2 and 1.2 g cm(sup -3) but are very poorly determined, if at all. As comets age they develop nonvolitile crusts on their surfaces which eventually render them inactive, similar in appearance to carbonaceous asteroids. However, dormant comets may continue to show sporadic activity and outbursts for some time before they become truly extinct. The source of the long-period comets is the Oort cloud, a vast spherical cloud of perhaps 10(sup 12) to 10(sup 13) comets surrounding the solar system and extending to interstellar distances. The likely source for short-period comets is the Kuiper belt. a ring of perhaps 10(sup 8) to 10(sup 10) remnant icy planetesimals beyond the orbit of Neptune, though some short-period comets may also be long-period comets from the Oort cloud which have been perturbed into short-period orbits.
NASA Astrophysics Data System (ADS)
Battye, R. A.; Manton, N. S.; Sutcliffe, P. M.
We review recent work on the modelling of atomic nuclei as quantised Skyrmions, using Skyrme's original model with pion fields only. Skyrmions are topological soliton solutions, whose conserved topological charge B is identified with the baryon number of a nucleus. Apart from an energy and length scale, the Skyrme model has just one dimensionless parameter m, proportional to the pion mass. It has been found that a good fit to experimental nuclear data requires m to be of order 1. The Skyrmions for B up to 7 have been known for some time, and are qualitatively insensitive to whether m is zero or of order 1. However, for baryon numbers B = 8 and above, the Skyrmions have quite a compact structure for m of order 1, rather than the hollow polyhedral structure found when m = 0. One finds for baryon numbers which are multiples of four, that the Skyrmions are composed of B = 4 sub-units, as in the α-particle model of nuclei. The rational map ansatz gives a useful approximation to the Skyrmion solutions for all baryon numbers when m = 0. For m of order 1, it gives a good approximation for baryon numbers up to 7, and generalisations of this ansatz are helpful for higher baryon numbers. We briefly review the work from the 1980s and 90s on the semiclassical rigidbody quantisation of Skyrmions for B = 1, 2, 3 and 4. We then discuss more recent work extending this method to B = 6, 7, 8, 10 and 12. We determine the quantum states of the Skyrmions, finding their spins, isospins and parities, and compare with the experimental data on the ground and excited states of nuclei up to mass number 12.
Decay spectroscopy of N < Z nuclei around 100Sn
NASA Astrophysics Data System (ADS)
Park, Joochun (Jason); Eurica Collaboration
2016-09-01
Many interesting topics in both nuclear structure and nuclear astrophysics converge on the doubly-magic nucleus 100Sn and nuclei in its vicinity. Among them are the boundaries of proton dripline, the effect of pn interaction in self-conjugate nuclei, and the decay properties required for rp -process calculations in nucleosynthesis models. Despite many studies, experimental knowledge of these nuclides has remained scarce due to low production cross sections and a lack of intense beams. However, record quantities of exotic N = Z isotopes around 100Sn were produced at RIKEN Radioactive Isotope Beam Factory, via fragmentation of a 124Xe beam on a thin 9Be target. Based on the obtained data, 89Rh and 93Ag have been confirmed to be proton unbound. Half-lives of isotopes near the proton dripline will be presented with improved precision compared to literature values. In addition, strategies to determine Qβ for ft values, and consequently the Fermi/Gamow-Teller transition strengths of these isotope decays will be discussed. Work supported by the Natural Sciences and Engineering Research Council of Canada and the National Research Council of Canada.
Total photoabsorption in nuclei
Bianchi, N.
1992-06-01
The Frascati-Genova collaboration proposes to measure the total photonuclear cross section on a wide range of nuclei between 500 MeV and 2 GeV, to obtain informations on the interaction of baryon resonances with nucleons and on the onset of the shadowing effect. The experiment could be performed in the Hall B as soon as the tagging facility will be ready and before the end of the installation of the CLAS spectrometer. The requirements for the photon beam, like maximum energy, intensity and beam definition, are not so strong so that the experiment would also be a good first test of the tagged photon facility.
NASA Astrophysics Data System (ADS)
Beane, Silas
2016-09-01
Over the last several decades, theoretical nuclear physics has been evolving from a very-successful phenomenology of the properties of nuclei, to a first-principles derivation of the properties of visible matter in the Universe from the known underlying theories of Quantum Chromodynamics (QCD) and Electrodynamics. Many nuclear properties have now been calculated using lattice QCD, a method for treating QCD numerically with large computers. In this talk, some of the most recent results in this frontier area of nuclear theory will be reviewed.
Predictions for Superheavy Nuclei
NASA Astrophysics Data System (ADS)
Kumar, Krishna
1990-01-01
The Dynamic Deformation Model has been extended to the problem of fission in such a way that several thousand channels including particle-decay, α-decay, heavy-ion-emission, asymmetric fission, and symmetric fission can be taken into account. The model also includes a Kinetic Shell Correction which was ignored in previous predictions for Superheavy nuclei. This model is in better agreement with experimental life-times. A new location of the Superheavy peak is predicted at Z = 116 (eka-Polonium), A = 300, total half-life = 1079 years. New heavy-ion-fusion experiments and the means of identifying the Superheavy Elements are suggested.
Foloppe, Nicolas; Chen, I-Jen
2016-05-15
There has been an explosion of structural information for pharmaceutical compounds bound to biological targets, but the conformations and dynamics of compounds free in solution are poorly characterized, if at all. Yet, knowledge of the unbound state is essential to understand the fundamentals of molecular recognition, including the much debated conformational intramolecular reorganization energy of a compound upon binding (ΔEReorg). Also, dependable observation of the unbound compounds is important for ligand-based drug discovery, e.g. with pharmacophore modelling. Here, these questions are addressed with long (⩾0.5μs) state-of-the-art molecular dynamics (MD) simulations of 26 compounds (including 7 approved drugs) unbound in explicit solvent. These compounds were selected to be chemically diverse, with a range of flexibility, and good quality bioactive X-ray structures. The MD-simulated free compounds are compared to their bioactive structure and conformers generated with ad hoc sampling in vacuo or with implicit generalized Born (GB) aqueous solvation models. The GB conformational models clearly depart from those obtained in explicit solvent, and suffer from conformational collapse almost as severe as in vacuo. Thus, the global energy minima in vacuo or with GB are not suitable representations of the unbound state, which can instead be extensively sampled by MD simulations. Many, but not all, MD-simulated compounds displayed some structural similarity to their bioactive structure, supporting the notion of conformational pre-organization for binding. The ligand-protein complexes were also simulated in explicit solvent, to estimate ΔEReorg as an enthalpic difference ΔHReorg between the intramolecular energies in the bound and unbound states. This fresh approach yielded ΔHReorg values⩽6kcal/mol for 18 out of 26 compounds. For three particularly polar compounds 15⩽ΔHReorg⩽20kcal/mol, supporting the notion that ΔHReorg can be substantial. Those large
Nuclei at HERA and heavy ion physics
Gavin, S.; Strikman, M.
1995-12-31
Copies of 16 viewgraph sets from a workshop held at Brookhaven National Laboratory, 17-18 November, 1995. Titles of talks: HERA: The Present; HERA: Potential with Nuclei; Review of Hadron-Lepton Nucleus Data; Fermilab E665: results in muon scattering; Interactions of Quarks and Gluons with Nuclear Matter; Rescattering in Nuclear Targets for Photoproduction and DIS; Structure Functions and Nuclear Effect at PHENIX; Probing Spin-Averaged and Spin-Dependent Parton Distributions Using the Solenoidal Tracker at RHIC (STAR); Jet Quenching in eA, pA, AA; Nuclear Gluon Shadowing via Continuum Lepton Pairs; What can we learn from HERA with a colliding heavy ion beam? The limiting curve of leading particles at infinite A; Coherent Production of Vector Mesons off Light Nuclei in DIS; A Model of High Parton Densities in PQCD; Gluon Production for Weizaecker-Williams Field in Nucleus-Nucleus Collisions; Summary Talk.
Reverberation mapping of active galactic nuclei
NASA Technical Reports Server (NTRS)
Peterson, Bradley M.
1993-01-01
The broad emission lines in the spectra of active galactic nuclei respond to variations in the luminosity of the central continuum source with a delay due to light-travel time effects within the emission-line region. It is therefore possible through the process of 'reverberation mapping' to determine the geometry and kinematics of the emission-line region by careful monitoring of the continuum variations and the resulting emission-line response. In this review, I will discuss progress in application of the reverberation mapping technique. I will describe the underlying assumptions and limitations of the method, discuss how the results obtained to date are changing our understanding of active nuclei, and outline several new questions that might be addressed through further reverberation mapping programs.
NASA Astrophysics Data System (ADS)
García-Recio, C.; Nieves, J.; Tolos, L.
2010-06-01
The energies and widths of several D0 meson bound states for different nuclei are obtained using a D-meson selfenergy in the nuclear medium, which is evaluated in a selfconsistent manner using techniques of unitarized coupled-channel theory. The kernel of the meson-baryon interaction is based on a model that treats heavy pseudoscalar and heavy vector mesons on equal footing, as required by heavy quark symmetry. We find D0 bound states in all studied nuclei, from 12C up to 208Pb. The inclusion of vector mesons is the keystone for obtaining an attractive D-nucleus interaction that leads to the existence of D0-nucleus bound states, as compared to previous studies based on SU(4) flavor symmetry. In some cases, the half widths are smaller than the separation of the levels, what makes possible their experimental observation by means of a nuclear reaction. This can be of particular interest for the future P¯ANDA@FAIR physics program. We also find a D+ bound state in 12C, but it is too broad and will have a significant overlap with the energies of the continuum.
Heavy and Superheavy Atomic Nuclei
NASA Astrophysics Data System (ADS)
Sobiczewski, Adam
2008-10-01
The appearance and development of the concept of super-heavy atomic nuclei are described. The concept appeared during the studies of the limits of the nuclear chart and of the periodic table of the chemical elements. The article concentrates on theoretical studies of the properties of heaviest nuclei. Results of these studies are illustrated and discussed. Prospects for a nearest future of the research of heaviest nuclei are outlined.
Robbins, Arthur H.; Coman, Roxana M.; Bracho-Sanchez, Edith; Fernandez, Marty A.; Gilliland, C.Taylor; Li, Mi; Agbandje-McKenna, Mavis; Wlodawer, Alexander; Dunn, Ben M.; McKenna, Robert
2010-03-12
The crystal structure of the unbound form of HIV-1 subtype A protease (PR) has been determined to 1.7 {angstrom} resolution and refined as a homodimer in the hexagonal space group P6{sub 1} to an R{sub cryst} of 20.5%. The structure is similar in overall shape and fold to the previously determined subtype B, C and F PRs. The major differences lie in the conformation of the flap region. The flaps in the crystal structures of the unbound subtype B and C PRs, which were crystallized in tetragonal space groups, are either semi-open or wide open. In the present structure of subtype A PR the flaps are found in the closed position, a conformation that would be more anticipated in the structure of HIV protease complexed with an inhibitor. The amino-acid differences between the subtypes and their respective crystal space groups are discussed in terms of the differences in the flap conformations.
Quantum steerability: Characterization, quantification, superactivation, and unbounded amplification
NASA Astrophysics Data System (ADS)
Hsieh, Chung-Yun; Liang, Yeong-Cherng; Lee, Ray-Kuang
2016-12-01
Quantum steering, also called Einstein-Podolsky-Rosen steering, is the intriguing phenomenon associated with the ability of spatially separated observers to steer—by means of local measurements—the set of conditional quantum states accessible by a distant party. In the light of quantum information, all steerable quantum states are known to be resources for quantum information processing tasks. Here, via a quantity dubbed steering fraction, we derive a simple, but general criterion that allows one to identify quantum states that can exhibit quantum steering (without having to optimize over the measurements performed by each party), thus making an important step towards the characterization of steerable quantum states. The criterion, in turn, also provides upper bounds on the largest steering-inequality violation achievable by arbitrary finite-dimensional maximally entangled states. For the quantification of steerability, we prove that a strengthened version of the steering fraction is a convex steering monotone and demonstrate how it is related to two other steering monotones, namely, steerable weight and steering robustness. Using these tools, we further demonstrate the superactivation of steerability for a well-known family of entangled quantum states, i.e., we show how the steerability of certain entangled, but unsteerable quantum states can be recovered by allowing joint measurements on multiple copies of the same state. In particular, our approach allows one to explicitly construct a steering inequality to manifest this phenomenon. Finally, we prove that there exist examples of quantum states (including some which are unsteerable under projective measurements) whose steering-inequality violation can be arbitrarily amplified by allowing joint measurements on as little as three copies of the same state. For completeness, we also demonstrate how the largest steering-inequality violation can be used to bound the largest Bell-inequality violation and derive
Neutron knockout of {sup 12}Be populating neutron-unbound states in {sup 11}Be
Peters, W. A.; Baumann, T.; Lecouey, J.-L.; Schiller, A.; Yoneda, K.; Brown, B. A.; Frank, N.; Thoennessen, M.; Brown, J.; DeYoung, P. A.; Peaslee, G. F.; Finck, J. E.; Jones, K. L.; Luther, B.; Rogers, W. F.; Tostevin, J. A.
2011-05-15
Neutron-unbound resonant states of {sup 11}Be were populated in neutron knockout reactions from {sup 12}Be and identified by {sup 10}Be-n coincidence measurements. A resonance in the decay-energy spectrum at 80(2) keV was attributed to a highly excited unbound state in {sup 11}Be at 3.949(2) MeV decaying to the 2{sup +} excited state in {sup 10}Be. A knockout cross section of 15(3) mb was inferred for this 3.949(2) MeV state, suggesting a spectroscopic factor near unity for this 0p3/2{sup -} level, consistent with the detailed shell model calculations.
Unbound states of (32)Cl andthe (31)S(p,gamma)(32)Cl reaction rate
Matos, M.; Blackmon, Jeff C; Linhardt, Laura; Bardayan, Daniel W; Nesaraja, Caroline D; Clark, Jason; Diebel, C.; O'Malley, Patrick; Parker, P.D.
2011-01-01
The {sup 31}S(p,{gamma}){sup 32}Cl reaction is expected to provide the dominant break-out path from the SiP cycle in novae and is important for understanding enrichments of sulfur observed in some nova ejecta. We studied the {sup 32}S(3He,t){sup 32}Cl charge-exchange reaction to determine properties of proton-unbound levels in {sup 32}Cl that have previously contributed significant uncertainties to the {sup 31}S(p,{gamma}){sup 32}Cl reaction rate. Measured triton magnetic rigidities were used to determine excitation energies in {sup 32}Cl. Proton-branching ratios were obtained by detecting decay protons from unbound {sup 32}Cl states in coincidence with tritons. An improved {sup 31}S(p,{gamma}){sup 32}Cl reaction rate was calculated including robust statistical and systematic uncertainties.
NASA Astrophysics Data System (ADS)
Abboud, Toufic; Joly, Patrick; Rodríguez, Jerónimo; Terrasse, Isabelle
2011-07-01
This work deals with the numerical simulation of wave propagation on unbounded domains with localized heterogeneities. To do so, we propose to combine a discretization based on a discontinuous Galerkin method in space and explicit finite differences in time on the regions containing heterogeneities with the retarded potential method to account the unbounded nature of the computational domain. The coupling formula enforces a discrete energy identity ensuring the stability under the usual CFL condition in the interior. Moreover, the scheme allows to use a smaller time step in the interior domain yielding to quasi-optimal discretization parameters for both methods. The aliasing phenomena introduced by the local time stepping are reduced by a post-processing by averaging in time obtaining a stable and second order consistent (in time) coupling algorithm. We compute the numerical rate of convergence of the method for an academic problem. The numerical results show the feasibility of the whole discretization procedure.
Deadlock checking for one-place unbounded Petri nets based on modified reachability trees.
Ding, ZhiJun; Jiang, ChangJun; Zhou, MengChu
2008-06-01
A deadlock-checking approach for one-place unbounded Petri nets is presented based on modified reachability trees (MRTs). An MRT can provide some useful information that is lost in a finite reachability tree, owing to MRT's use of the expression a + bn(i) rather than symbol omega to represent the value of the components of a marking. The information is helpful to property analysis of unbounded Petri nets. For the deadlock-checking purpose, this correspondence paper classifies full conditional nodes in MRT into two types: true and fake ones. Then, an algorithm is proposed to determine whether a full conditional node is true or not. Finally, a necessary and sufficient condition of deadlocks is presented. Examples are given to illustrate the method.
A Boolean Approach to Unbounded, Fully Symbolic Model Checking of Timed Automata
2003-03-01
reachability properties (these can express safety and bounded-liveness properties [1]). Uppaal2k and Kronos are unbounded, symbolic model checkers that...explicitly enumerate the discrete component of the state space. Kronos uses Difference Bound Matrices (DBMs) as the symbolic representation [19] of the...difference. Note that while Kronos can check arbitrary TCTL formulas, Uppaal2k is limited to checking reachability properties and very restricted liveness
Gyroscope precession along unbound equatorial plane orbits around a Kerr black hole
NASA Astrophysics Data System (ADS)
Bini, Donato; Geralico, Andrea; Jantzen, Robert T.
2016-12-01
The precession of a test gyroscope along unbound equatorial plane geodesic orbits around a Kerr black hole is analyzed with respect to a static reference frame whose axes point towards the "fixed stars." The accumulated precession angle after a complete scattering process is evaluated and compared with the corresponding change in the orbital angle. Limiting results for the nonrotating Schwarzschild black hole case are also discussed.
Nagaya, Yoko; Nozaki, Yoshitane; Kobayashi, Kazumasa; Takenaka, Osamu; Nakatani, Yosuke; Kusano, Kazutomi; Yoshimura, Tsutomu; Kusuhara, Hiroyuki
2014-01-01
In central nervous system drug discovery, cerebrospinal fluid (CSF) drug concentration (C(CSF)) has been widely used as a surrogate for unbound brain concentrations (C(u,brain)). However, previous rodent studies demonstrated that when drugs undergo active efflux by transporters, such as P-glycoprotein (P-gp), at the blood-brain barrier, the C(CSF) overestimates the corresponding C(u,brain). To investigate the utility of C(CSF) as a surrogate for interstitial fluid (ISF) concentration (C(ISF)) in nonhuman primates, this study simultaneously determined the C(CSF) and C(ISF) of 12 compounds, including P-gp substrates, under steady-state conditions in cynomolgus monkeys using intracerebral microdialysis coupled with cisternal CSF sampling. Unbound plasma concentrations of non- or weak P-gp substrates were within 2.2-fold of the C(ISF) or C(CSF), whereas typical P-gp substrates (risperidone, verapamil, desloratadine, and quinidine) showed ISF-to-plasma unbound (K(p,uu,ISF)) and CSF-to-plasma unbound concentration ratios (K(p,uu,CSF)) that were appreciably lower than unity. Although the K(p,uu,CSF) of quinidine, verapamil, and desloratadine showed a trend of overestimating the K(p,uu,ISF), K(p,uu,CSF) showed a good agreement with K(p,uu,ISF) within 3-fold variations for all compounds examined. C(u,brain) of some basic compounds, as determined using brain homogenates, overestimated the C(ISF) and C(CSF). Therefore, C(CSF) could be used as a surrogate for C(ISF) in nonhuman primates.
Tsai, Danny; Stewart, Penelope; Goud, Rajendra; Gourley, Stephen; Hewagama, Saliya; Krishnaswamy, Sushena; Wallis, Steven C; Lipman, Jeffrey; Roberts, Jason A
2016-12-01
In the absence of specific data to guide optimal dosing, this study aimed to describe the pharmacokinetics of ceftriaxone in severely septic Australian Indigenous patients and to assess achievement of the pharmacodynamic target of the regimens prescribed. A pharmacokinetic study was conducted in a remote hospital intensive care unit in patients receiving ceftriaxone dosing of 1 g every 12 h (q12h). Serial blood and urine samples were collected over one dosing interval on two consecutive days. Samples were assayed using a validated chromatography method for total and unbound concentrations. Concentration-time data collected were analysed with a non-compartmental approach. A total of 100 plasma samples were collected from five subjects. Ceftriaxone clearance, volume of distribution at steady-state, elimination half-life and elimination rate constant estimates were 0.9 (0.6-1.5) L/h, 11.2 (7.6-13.4) L, 9.5 (3.2-10.2) h and 0.07 (0.07-0.21) h(-1), respectively. The unbound fraction of ceftriaxone ranged between 14% and 43%, with a higher unbound fraction present at higher total concentrations. The unbound concentrations at 720 min from the initiation of infusion for the first and second dosing intervals were 7.2 (4.8-10.7) mg/L and 7.8 (4.7-12.1) mg/L respectively, which exceeds the minimum inhibitory concentration of all typical target pathogens. In conclusion, the regimen of ceftriaxone 1 g q12h is adequate for critically ill Australian Indigenous patients with severe sepsis caused by non-resistant pathogens.
An Extension of the Argument Principle and Nyquist Criterion to Systems with Unbounded Generators
2006-04-17
APRIL 17, 2006 1 An Extension of the Argument Principle and Nyquist Criterion to Systems with Unbounded Generators Makan Fardad and Bassam Bamieh...FA9550-04-1-0207 and NSF grant ECS-0323814. M. Fardad and B. Bamieh are with the Department of Mechanical and Environmental Engineering, University of...California, Santa Barbara, CA 93105-5070. email: fardad @engineering.ucsb.edu, bamieh@engineering.ucsb.edu Report Documentation Page Form ApprovedOMB No
A multi-layered active target for the study of neutron-unbound nuclides at NSCL
NASA Astrophysics Data System (ADS)
Freeman, Jessica; Gueye, Paul; Redpath, Thomas; MoNA Collaboration
2017-01-01
The characteristics of neutron-unbound nuclides were investigated using a multi-layered Si/Be active target designed for use with the MoNA/LISA setup at the National Superconducting Cyclotron (NSCL). The setup consists of the MoNA/LISA arrays (for neutron detection) and a superconducting sweeper magnet (for charged separation) to identify products following the decay of neutron unbound states. The segmented target consisted of three 700 mg/cm2 beryllium targets and four 0.14 mm thick 62x62 mm2 silicon detectors. As a commissioning experiment for the target the decay of two-neutron unbound 26O populated in a one-proton removal reaction from a radioactive 27F beam was performed. The 27F secondary radioactive beam from the NSCL's Coupled Cyclotron Facility was produced from the fragmentation of a 140 MeV/u 48Ca beam incident on a thick beryllium target and then cleanly selected by the A1900 fragment separator. The energy loss and position spectra of the incoming beam and reaction products were used to calibrate the Silicon detectors to within 1.5% in both energy and position. A dedicated Geant4 model of the target was developed to simulate the energy loss within the target. A description of the experimental setup, simulation work, and energy and position calibration will be presented. DoE/NNSA - DE-NA0000979.
On one-dimensional compressible Navier-Stokes equations for a reacting mixture in unbounded domains
NASA Astrophysics Data System (ADS)
Li, Siran
2017-10-01
In this paper we consider the one-dimensional Navier-Stokes system for a heat-conducting, compressible reacting mixture which describes the dynamic combustion of fluids of mixed kinds on unbounded domains. This model has been discussed on bounded domains by Chen (SIAM J Math Anal 23:609-634, 1992) and Chen-Hoff-Trivisa (Arch Ration Mech Anal 166:321-358, 2003), among others, in which the reaction rate function is a discontinuous function obeying the Arrhenius' law of thermodynamics. We prove the global existence of weak solutions to this model on one-dimensional unbounded domains with large initial data in H^1. Moreover, the large-time behaviour of the weak solution is identified. In particular, the uniform-in-time bounds for the temperature and specific volume have been established via energy estimates. For this purpose we utilise techniques developed by Kazhikhov-Shelukhin (cf. Kazhikhov in Siber Math J 23:44-49, 1982; Solonnikov and Kazhikhov in Annu Rev Fluid Mech 13:79-95, 1981) and refined by Jiang (Commun Math Phys 200:181-193, 1999, Proc R Soc Edinb Sect A 132:627-638, 2002), as well as a crucial estimate in the recent work by Li-Liang (Arch Ration Mech Anal 220:1195-1208, 2016). Several new estimates are also established, in order to treat the unbounded domain and the reacting terms.
VLDL hydrolysis by LPL activates PPAR-alpha through generation of unbound fatty acids.
Ruby, Maxwell A; Goldenson, Benjamin; Orasanu, Gabriela; Johnston, Thomas P; Plutzky, Jorge; Krauss, Ronald M
2010-08-01
Recent evidence suggests that lipoproteins serve as circulating reservoirs of peroxisomal proliferator activated receptor (PPAR) ligands that are accessible through lipolysis. The present study was conducted to determine the biochemical basis of PPAR-alpha activation by lipolysis products and their contribution to PPAR-alpha function in vivo. PPAR-alpha activation was measured in bovine aortic endothelial cells following treatment with human plasma, VLDL lipolysis products, or oleic acid. While plasma failed to activate PPAR-alpha, oleic acid performed similarly to VLDL lipolysis products. Therefore, fatty acids are likely to be the PPAR-alpha ligands generated by VLDL lipolysis. Indeed, unbound fatty acid concentration determined PPAR-alpha activation regardless of fatty acid source, with PPAR-alpha activation occurring only at unbound fatty acid concentrations that are unachievable under physiological conditions without lipase action. In mice, a synthetic lipase inhibitor (poloxamer-407) attenuated fasting-induced changes in expression of PPAR-alpha target genes. Apolipoprotein CIII (apoCIII), an endogenous inhibitor of lipoprotein and hepatic lipase, regulated access to the lipoprotein pool of PPAR-alpha ligands, because addition of exogenous apoCIII inhibited, and removal of endogenous apoCIII potentiated, lipolytic PPAR-alpha activation. These data suggest that the PPAR-alpha response is generated by unbound fatty acids released locally by lipase activity and not by circulating plasma fatty acids.
Nucleomorphs: enslaved algal nuclei.
Cavalier-Smith, T
2002-12-01
Nucleomorphs of cryptomonad and chlorarachnean algae are the relict, miniaturised nuclei of formerly independent red and green algae enslaved by separate eukaryote hosts over 500 million years ago. The complete 551 kb genome sequence of a cryptomonad nucleomorph confirms that cryptomonads are eukaryote-eukaryote chimeras and greatly illuminates the symbiogenetic event that created the kingdom Chromista and their alveolate protozoan sisters. Nucleomorph membranes may, like plasma membranes, be more enduring after secondary symbiogenesis than are their genomes. Partial sequences of chlorarachnean nucleomorphs indicate that genomic streamlining is limited by the mutational difficulty of removing useless introns. Nucleomorph miniaturisation emphasises that selection can dramatically reduce eukaryote genome size and eliminate most non-functional nuclear non-coding DNA. Given the differential scaling of nuclear and nucleomorph genomes with cell size, it follows that most non-coding nuclear DNA must have a bulk-sequence-independent function related to cell volume.
NASA Astrophysics Data System (ADS)
Xu, Renxin
What is the real nature of pulsars? This is essentially a question of the fundamental strong interaction between quarks at low-energy scale and hence of the non-perturbative quantum chromo-dynamics, the solution of which would certainly be meaningful for us to understand one of the seven millennium prize problems (i.e., "Yang-Mills Theory") named by the Clay Mathematical Institute. After a historical note, it is argued here that a pulsar is very similar to an extremely big nucleus, but is a little bit different from the gigantic nucleus speculated 80 years ago by L. Landau. The paper demonstrates the similarity between pulsars and gigantic nuclei from both points of view: the different manifestations of compact stars and the general behavior of the strong interaction.
NASA Astrophysics Data System (ADS)
Hütt, M.-Th.; L'vov, A. I.; Milstein, A. I.; Schumacher, M.
2000-01-01
The concept of Compton scattering by even-even nuclei from giant-resonance to nucleon-resonance energies and the status of experimental and theoretical researches in this field are outlined. The description of Compton scattering by nuclei starts from different complementary approaches, namely from second-order S-matrix and from dispersion theories. Making use of these, it is possible to incorporate into the predicted nuclear scattering amplitudes all the information available from other channels, viz. photon-nucleon and photon-meson channels, and to efficiently make use of models of the nucleon, the nucleus and the nucleon-nucleon interaction. The total photoabsorption cross section constrains the nuclear scattering amplitude in the forward direction. The specific information obtained from Compton scattering therefore stems from the angular dependence of the nuclear scattering amplitude, providing detailed insight into the dynamics of the nuclear and nucleon degrees of freedom and into the interplay between them. Nuclear Compton scattering in the giant-resonance energy-region provides information on the dynamical properties of the in-medium mass of the nucleon. Most prominently, the electromagnetic polarizabilities of the nucleon in the nuclear medium can be extracted from nuclear Compton scattering data obtained in the quasi-deuteron energy-region. In our description of this latter process special emphasis is laid upon the exploration of many-body and two-body effects entering into the nuclear dynamics. Recent results are presented for two-body effects due to the mesonic seagull amplitude and due to the excitation of nucleon internal degrees of freedom accompanied by meson exchanges. Due to these studies the in-medium electromagnetic polarizabilities are by now well understood, whereas the understanding of nuclear Compton scattering in the Δ-resonance range is only at the beginning. Furthermore, phenomenological methods how to include retardation effects in the
Echo Mapping of Active Galactic Nuclei
NASA Astrophysics Data System (ADS)
Horne, K.
Echo mapping exploits light travel time delays, revealed by multi-wavelength variability studies, to map the geometry, kinematics, and physical conditions of reprocessing sites in photo-ionized gas flows. In active galactic nuclei (AGN), the ultraviolet to near infrared light arises in part from reprocessing of EUV and X-ray light from a compact and erratically variable source in the nucleus. The observed time delays, 0.1-2 days for the continuum and 1-100 days for the broad emission lines, probe regions only micro-arcseconds from the nucleus. Emission-line delays reveal radially stratified ionization zones, identify the nature of the gas motions, and estimate the masses of the central black holes. Continuum time delays map the temperature-radius structure of AGN accretion discs, and provide distances that may be accurate enough to realize the potential of AGNs as cosmological probes.
STELLAR TRANSITS IN ACTIVE GALACTIC NUCLEI
Beky, Bence; Kocsis, Bence E-mail: bkocsis@cfa.harvard.edu
2013-01-01
Supermassive black holes (SMBHs) are typically surrounded by a dense stellar population in galactic nuclei. Stars crossing the line of site in active galactic nuclei (AGNs) produce a characteristic transit light curve, just like extrasolar planets do when they transit their host star. We examine the possibility of finding such AGN transits in deep optical, UV, and X-ray surveys. We calculate transit light curves using the Novikov-Thorne thin accretion disk model, including general relativistic effects. Based on the expected properties of stellar cusps, we find that around 10{sup 6} solar mass SMBHs, transits of red giants are most common for stars on close orbits with transit durations of a few weeks and orbital periods of a few years. We find that detecting AGN transits requires repeated observations of thousands of low-mass AGNs to 1% photometric accuracy in optical, or {approx}10% in UV bands or soft X-ray. It may be possible to identify stellar transits in the Pan-STARRS and LSST optical and the eROSITA X-ray surveys. Such observations could be used to constrain black hole mass, spin, inclination, and accretion rate. Transit rates and durations could give valuable information on the circumnuclear stellar clusters as well. Transit light curves could be used to image accretion disks with unprecedented resolution, allowing us to resolve the SMBH silhouette in distant AGNs.
New Measurements of High-Momentum Nucleons and Short-Range Structures in Nuclei
Fomin, N.; Arrington, J.; Asaturyan, R.; ...
2012-02-01
We present new, high-Q2 measurements of inclusive electron scattering from high-momentum nucleons in nuclei. This yields an improved extraction of the strength of two-nucleon correlations for several nuclei, including light nuclei where clustering effects can, for the first time, be examined. The data extend to the kinematic regime where three-nucleon correlations are expected to dominate and we observe significantly greater strength in this region than previous measurements.
New Measurements of High-Momentum Nucleons and Short-Range Structures in Nuclei
Fomin, N.; Arrington, J.; Asaturyan, R.; Benmokhtar, F.; Boeglin, W.; Bosted, P.; Bruell, A.; Bukhari, M. H. S.; Christy, M. E.; Chudakov, E.; Clasie, B.; Connell, S. H.; Dalton, M. M.; Daniel, A.; Day, D. B.; Dutta, D.; Ent, R.; El Fassi, L.; Fenker, H.; Filippone, B. W.; Garrow, K.; Gaskell, D.; Hill, C.; Holt, R. J.; Horn, T.; Jones, M. K.; Jourdan, J.; Kalantarians, N.; Keppel, C. E.; Kiselev, D.; Kotulla, M.; Lindgren, R.; Lung, A. F.; Malace, S.; Markowitz, P.; McKee, P.; Meekins, D. G.; Mkrtchyan, H.; Navasardyan, T.; Niculescu, G.; Opper, A. K.; Perdrisat, C.; Potterveld, D. H.; Punjabi, V.; Qian, X.; Reimer, P. E.; Roche, J.; Rodriguez, V. M.; Rondon, O.; Schulte, E.; Seely, J.; Segbefia, E.; Slifer, K.; Smith, G. R.; Solvignon, P.; Tadevosyan, V.; Tajima, S.; Tang, L.; Testa, G.; Trojer, R.; Tvaskis, V.; Vulcan, W. F.; Wasko, C.; Wesselmann, F. R.; Wood, S. A.; Wright, J.; Zheng, X.
2012-02-01
We present new, high-Q^{2} measurements of inclusive electron scattering from high-momentum nucleons in nuclei. This yields an improved extraction of the strength of two-nucleon correlations for several nuclei, including light nuclei where clustering effects can, for the first time, be examined. The data extend to the kinematic regime where three-nucleon correlations are expected to dominate and we observe significantly greater strength in this region than previous measurements.
Probing the hidden secrets of Seyfert nuclei.
NASA Astrophysics Data System (ADS)
Appenzeller, I.; Wagner, S.
1990-06-01
The nuclei of active galaxies are clearly among the most spectacular and violent places that can be found in our present universe. Most extreme are the bright Quasars, where we observe a total energy output equivalent to a large galaxy cluster from galactic core regions comparable in size to our solar system. In addition to optical and radio radiation we often observe intense X-ray and even energetic Gamma radiation as well as collimated streams of matter moving at velocities close to the velocity of light.
Reactions and structure of exotic nuclei
Esbensen, H.
1993-08-01
Radioactive beam experiments have made it possible to study the structure of light neutron rich nuclei. A characteristic feature is a large dipole strength near threshold. An excellent example is the loosely bound nucleus ``Li for which Coulomb dissociation plays a dominant role in breakup reactions on a high Z target. I will describe a three-body model and apply it to calculate the dipole response of {sup 11}Li and the momentum distributions for the three-body breakup reaction: {sup 11}Li {yields} {sup 9}Li+n+n, and comparisons will be made to recent three-body coincidence measurements.
Liu, Xingrong; Van Natta, Kristine; Yeo, Helen; Vilenski, Olga; Weller, Paul E; Worboys, Philip D; Monshouwer, Mario
2009-04-01
The objective of the present study was to examine the accuracy of using unbound brain concentration determined by a brain homogenate method (C(ub)), cerebral spinal fluid concentration (C(CSF)), and unbound plasma concentration (C(up)) as a surrogate for brain interstitial fluid concentration determined by brain microdialysis (C(m)). Nine compounds-carbamazepine, citalopram, ganciclovir, metoclopramide, N-desmethylclozapine, quinidine, risperidone, 9-hydroxyrisperidone, and thiopental-were selected, and each was administered as an intravenous bolus (up to 5 mg/kg) followed by a constant intravenous infusion (1-9 mg/kg/h) for 6 h in rats. For eight of the nine compounds, the C(ub)s were within 3-fold of their C(m); thiopental had a C(m) 4-fold of its C(ub). The C(CSF)s of eight of the nine compounds were within 3-fold of their corresponding C(m); 9-hydroxyrisperidone showed a C(CSF) 5-fold of its C(m). The C(up)s of five of the nine compounds were within 3-fold of their C(m); four compounds (ganciclovir, metoclopramide, quinidine, and 9-hydroxyrisperidone) had C(up)s 6- to 14-fold of their C(m). In conclusion, the C(ub) and C(CSF) were within 3-fold of the C(m) for the majority of the compounds tested. The C(up)s were within 3-fold of C(m) for lipophilic non-P-glycoprotein (-P-gp) substrates and greater than 3-fold of C(m) for hydrophilic or P-gp substrates. The present study indicates that the brain homogenate and cerebral spinal fluid methods may be used as surrogate methods to predict brain interstitial fluid concentrations within 3-fold of error in drug discovery and development settings.
Robertson, R.G.H.
1980-01-01
A summary of parity violating effects in nuclei is given. Thanks to vigorous experimental and theoretical effort, it now appears that a reasonably well-defined value for the weak isovector ..pi..-nucleon coupling constant can be obtained. There is one major uncertainty in the analysis, namely the M2/E1 mixing ratio for the 2.79 MeV transition in /sup 21/Ne. This quantity is virtually impossible to calculate reliably and must be measured. If it turns out to be much larger than 1, then a null result in /sup 21/Ne is expected no matter what the weak interaction, so an experimental determination is urgently needed. The most promising approach is perhaps a measurement of the pair internal conversion coefficient. Of course, a direct measurement of a pure isovector case is highly desirable, and it is to be hoped that the four ..delta..T = 1 experiments will be pushed still further, and that improved calculations will be made for the /sup 6/Li case. Nuclear parity violation seems to be rapidly approaching an interesting and useful synthesis.
Ayala, A.L.; Ducati, M.B.G.; Levin, E.M.
1996-10-01
In this talk we present our detailed study (theory and numbers) on the shadowing corrections to the gluon structure functions for nuclei. Starting from rather controversial information on the nucleon structure function which is originated by the recent HERA data, we develop the Glauber approach for the gluon density in a nucleus based on Mueller formula and estimate the value of the shadowing corrections in this case. Then we calculate the first corrections to the Glauber approach and show that these corrections are big. Based on this practical observation we suggest the new evolution equation which takes into account the shadowing corrections and solve it. We hope to convince you that the new evolution equation gives a good theoretical tool to treat the shadowing corrections for the gluons density in a nucleus and, therefore, it is able to provide the theoretically reliable initial conditions for the time evolution of the nucleus-nucleus cascade. The initial conditions should be fixed both theoretically and phenomenologically before to attack such complicated problems as the mixture of hard and soft processes in nucleus-nucleus interactions at high energy or the theoretically reliable approach to hadron or/and parton cascades for high energy nucleus-nucleus interaction. 35 refs., 24 figs., 1 tab.
NASA Astrophysics Data System (ADS)
Benedetto, Andrea; D'Amico, Fabrizio; Tosti, Fabio
2013-04-01
It is well known that inter-particle friction and cohesion of soil particles and aggregates deeply affect the strength and deformation properties of soils, exerting critical effects on the bearing capacity of unbound pavement materials. In that respect, considering that strength characteristics of soil are highly dependent on particle interactions, and assuming a relationship between electric properties (e.g. electric permittivity) and bulk density of materials, a good correlation between mechanical and electric characteristics of soil is expected. In this work, Ground Penetrating Radar (GPR) techniques are used to investigate this topic. Two GPR equipment with same electronic characteristics and different survey configurations are used. Each radar operates with two ground-coupled antennae at 600 MHz and 1600 MHz central frequencies. Measurements are developed using 4 channels, 2 mono-static and 2 bi-static. The received signal is sampled in the time domain at dt = 7.8125 × 10-2 ns, and in the space domain every 2.4 × 10-2 m. A semi-empirical model is proposed for predicting the resilient modulus of sub-asphalt layers from GPR-derived data. Basically, the method requires to follow two steps. Firstly, laboratory tests are carried out for calibration, with the main focus to provide consistent empirical relationships between physical (e.g. bulk density) and electric properties. The second step is focused on the in-situ validation of results through soil strength measurements retrieved by CBR tests and Light Falling Weight Deflectometer (LFWD). On the basis of traditional empirical equations used for flexible pavement design, the following expression is proposed: -m Ei = αj?hj,i j=1 where Ei [MPa] is the ith expected resilient modulus of the surveyed soil under the line of scan, hj,i [m] is the ith thickness referred to the jth layer, and αj is a dielectric parameter calibrated as a function of the relative electric permittivity. The experimental setting requires
Status and perspectives of the search for Eta-Mesic nuclei
Moskal, Paweł Skurzok, Magdalena; Krzemień, Wojciech
2016-07-07
In this report the search for η-mesic nuclei is reviewed. The brief description of the experimental studies is presented with a focus on the possible production of the η-nucleus bound states for light nuclei like {sup 4}He and {sup 3}He.
Mukha, I; Grigorenko, L V; Xu, X; Acosta, L; Casarejos, E; Ciemny, A A; Dominik, W; Duénas-Díaz, J; Dunin, V; Espino, J M; Estradé, A; Farinon, F; Fomichev, A; Geissel, H; Golubkova, T A; Gorshkov, A; Janas, Z; Kamiński, G; Kiselev, O; Knöbel, R; Krupko, S; Kuich, M; Litvinov, Yu A; Marquinez-Durán, G; Martel, I; Mazzocchi, C; Nociforo, C; Ordúz, A K; Pfützner, M; Pietri, S; Pomorski, M; Prochazka, A; Rymzhanova, S; Sánchez-Benítez, A M; Scheidenberger, C; Sharov, P; Simon, H; Sitar, B; Slepnev, R; Stanoiu, M; Strmen, P; Szarka, I; Takechi, M; Tanaka, Y K; Weick, H; Winkler, M; Winfield, J S; Zhukov, M V
2015-11-13
Previously unknown isotopes (30)Ar and (29)Cl have been identified by measurement of the trajectories of their in-flight decay products (28)S+p+p and (28)S+p, respectively. The analysis of angular correlations of the fragments provided information on decay energies and the structure of the parent states. The ground states of (30)Ar and (29)Cl were found at 2.25(-0.10)(+0.15) and 1.8±0.1 MeV above the two- and one-proton thresholds, respectively. The lowest states in (30)Ar and (29)Cl point to a violation of isobaric symmetry in the structure of these unbound nuclei. The two-proton decay has been identified in a transition region between simultaneous two-proton and sequential proton emissions from the (30)Ar ground state, which is characterized by an interplay of three-body and two-body decay mechanisms. The first hint of a fine structure of the two-proton decay of (30)Ar*(2(+)) has been obtained by detecting two decay branches into the ground and first-excited states of the (28)S fragment.
INTERACTION OF RECOILING SUPERMASSIVE BLACK HOLES WITH STARS IN GALACTIC NUCLEI
Li Shuo; Liu, F. K.; Berczik, Peter; Spurzem, Rainer; Chen Xian E-mail: fkliu@bac.pku.edu.cn
2012-03-20
Supermassive black hole binaries (SMBHBs) are the products of frequent galaxy mergers. The coalescence of the SMBHBs is a distinct source of gravitational wave (GW) radiation. The detections of the strong GW radiation and their possible electromagnetic counterparts are essential. Numerical relativity suggests that the post-merger supermassive black hole (SMBH) gets a kick velocity up to 4000 km s{sup -1} due to the anisotropic GW radiations. Here, we investigate the dynamical coevolution and interaction of the recoiling SMBHs and their galactic stellar environments with one million direct N-body simulations including the stellar tidal disruption by the recoiling SMBHs. Our results show that the accretion of disrupted stars does not significantly affect the SMBH dynamical evolution. We investigate the stellar tidal disruption rates as a function of the dynamical evolution of oscillating SMBHs in the galactic nuclei. Our simulations show that most stellar tidal disruptions are contributed by the unbound stars and occur when the oscillating SMBHs pass through the galactic center. The averaged disruption rate is {approx}10{sup -6} M{sub Sun} yr{sup -1}, which is about an order of magnitude lower than that by a stationary SMBH at similar galactic nuclei. Our results also show that a bound star cluster is around the oscillating SMBH of about {approx}0.7% the black hole mass. In addition, we discover a massive cloud of unbound stars following the oscillating SMBH. We also investigate the dependence of the results on the SMBH masses and density slopes of the galactic nuclei.
del Amo, Eva M.; Ghemtio, Leo; Xhaard, Henri; Yliperttula, Marjo; Urtti, Arto; Kidron, Heidi
2013-01-01
Volume of distribution and fraction unbound are two key parameters in pharmacokinetics. The fraction unbound describes the portion of free drug in plasma that may extravasate, while volume of distribution describes the tissue access and binding of a drug. Reliable in silico predictions of these pharmacokinetic parameters would benefit the early stages of drug discovery, as experimental measuring is not feasible for screening purposes. We have applied linear and nonlinear multivariate approaches to predict these parameters: linear partial least square regression and non-linear recursive partitioning classification. The volume of distribution and fraction of unbound drug in plasma are predicted in parallel within the model, since the two are expected to be affected by similar physicochemical drug properties. Predictive models for both parameters were built and the performance of the linear models compared to models included in the commercial software Volsurf+. Our models performed better in predicting the unbound fraction (Q2 0.54 for test set compared to 0.38 with Volsurf+ model), but prediction accuracy of the volume of distribution was comparable to the Volsurf+ model (Q2 of 0.70 for test set compared to 0.71 with Volsurf+ model). The nonlinear classification models were able to identify compounds with a high or low volume of distribution (sensitivity 0.81 and 0.71, respectively, for test set), while classification of fraction unbound was less successful. The interrelationship between the volume of distribution and fraction unbound is investigated and described in terms of physicochemical descriptors. Lipophilicity and solubility descriptors were found to have a high influence on both volume of distribution and fraction unbound, but with an inverse relationship. PMID:24116008
Pfeifer, Nathan D; Harris, Kevin B; Yan, Grace Zhixia; Brouwer, Kim L R
2013-11-01
Prediction of clinical efficacy, toxicity, and drug-drug interactions may be improved by accounting for the intracellular unbound drug concentration (C(unbound)) in vitro and in vivo. Furthermore, subcellular drug distribution may aid in predicting efficacy, toxicity, and risk assessment. The present study was designed to quantify the intracellular C(unbound) and subcellular localization of drugs in rat sandwich-cultured hepatocytes (SCH) compared with rat isolated perfused liver (IPL) tissue. Probe drugs with distinct mechanisms of hepatocellular uptake and accumulation were selected for investigation. Following drug treatment, SCH and IPL tissues were homogenized and fractionated by differential centrifugation to enrich for subcellular compartments. Binding in crude lysate and cytosol was determined by equilibrium dialysis; the C(unbound) and intracellular-to-extracellular C(unbound) ratio (K(pu,u)) were used to describe accumulation of unbound drug. Total accumulation (K(pobserved)) in whole tissue was well predicted by the SCH model (within 2- to 3-fold) for the selected drugs. Ritonavir (K(pu,u) ∼1) was evenly distributed among cellular compartments, but highly bound, which explained the observed accumulation within liver tissue. Rosuvastatin was recovered primarily in the cytosolic fraction, but did not exhibit extensive binding, resulting in a K(pu,u) >1 in liver tissue and SCH, consistent with efficient hepatic uptake. Despite extensive binding and sequestration of furamidine within liver tissue, a significant portion of cellular accumulation was attributed to unbound drug (K(pu,u) >16), as expected for a charged, hepatically derived metabolite. Data demonstrate the utility of SCH to predict quantitatively total tissue accumulation and elucidate mechanisms of hepatocellular drug accumulation such as active uptake versus binding/sequestration.
Single-particle and collective motion in unbound deformed 39Mg
NASA Astrophysics Data System (ADS)
Fossez, K.; Rotureau, J.; Michel, N.; Liu, Quan; Nazarewicz, W.
2016-11-01
Background: Deformed neutron-rich magnesium isotopes constitute a fascinating territory where the interplay between collective rotation and single-particle motion is strongly affected by the neutron continuum. The unbound f p -shell nucleus 39Mg is an ideal candidate to study this interplay. Purpose: In this work, we predict the properties of low-lying resonant states of 39Mg, using a suite of realistic theoretical approaches rooted in the open quantum system framework. Method: To describe the spectrum and decay modes of 39Mg we use the conventional shell model, Gamow shell model, resonating group method, density matrix renormalization group method, and the nonadiabatic particle-plus-rotor model formulated in the Berggren basis. Results: The unbound ground state of 39Mg is predicted to be either a Jπ=7/2 - state or a 3/2 - state. A narrow Jπ=7/2 - ground-state candidate exhibits a resonant structure reminiscent of that of its one-neutron halo neighbor 37Mg, which is dominated by the f7 /2 partial wave at short distances and a p3 /2 component at large distances. A Jπ=3/2 - ground-state candidate is favored by the large deformation of the system. It can be associated with the 1/2 -[321 ] Nilsson orbital dominated by the ℓ =1 wave; hence its predicted width is large. The excited Jπ=1/2 - and 5 /2- states are expected to be broad resonances, while the Jπ=9/2 - and 11/2 - members of the ground-state rotational band are predicted to have very small neutron decay widths. Conclusion: We demonstrate that the subtle interplay between deformation, shell structure, and continuum coupling can result in a variety of excitations in an unbound nucleus just outside the neutron drip line.
Stem cell mechanics: Auxetic nuclei
NASA Astrophysics Data System (ADS)
Wang, Ning
2014-06-01
The nuclei of naive mouse embryonic stem cells that are transitioning towards differentiation expand when the cells are stretched and contract when they are compressed. What drives this auxetic phenotype is, however, unclear.
Quasi-geostrophic wave-CISK in an unbounded baroclinic shear
NASA Technical Reports Server (NTRS)
Snyder, Chris; Lindzen, Richard S.
1991-01-01
The free-shear problem, a minimal version of baroclinic, quasi-geostrophic wave-CISK is analyzed. The basic state consists of a zonal flow, unbounded above and below, with constant vertical shear and Brunt-Vaisala frequency and zero meridional gradient of the potential vorticity. Convective heating is parameterized in terms of the convergence below an arbitrary level. Consideration of the potential vorticity dynamics of the unstable modes illustrates how heating may act as a dynamical surrogate for potential vorticity gradients. Although highly idealized, the free-shear problem also explains much of the behavior of more general wave-CISK models.
NASA Technical Reports Server (NTRS)
Burns, John A.; Marrekchi, Hamadi
1993-01-01
The problem of using reduced order dynamic compensators to control a class of nonlinear parabolic distributed parameter systems was considered. Concentration was on a system with unbounded input and output operators governed by Burgers' equation. A linearized model was used to compute low-order-finite-dimensional control laws by minimizing certain energy functionals. Then these laws were applied to the nonlinear model. Standard approaches to this problem employ model/controller reduction techniques in conjunction with linear quadratic Gaussian (LQG) theory. The approach used is based on the finite dimensional Bernstein/Hyland optimal projection theory which yields a fixed-finite-order controller.
Sheng, Yin; Zeng, Zhigang
2017-09-01
In this paper, synchronization of stochastic reaction-diffusion neural networks with Dirichlet boundary conditions and unbounded discrete time-varying delays is investigated. By virtue of theories of partial differential equations, inequality methods, and stochastic analysis techniques, pth moment exponential synchronization and almost sure exponential synchronization of the underlying neural networks are developed. The obtained results in this study enhance and generalize some earlier ones. The effectiveness and merits of the theoretical criteria are substantiated by two numerical simulations. Copyright © 2017 Elsevier Ltd. All rights reserved.
UNBOUND GEODESICS FROM THE ERGOSPHERE AND THE MESSIER 87 JET PROFILE
Gariel, J.; Marcilhacy, G.; Santos, N. O. E-mail: gmarcilhacy@hotmail.com
2013-09-10
Assuming that the spin a of the black hole presumably located at the core of the active galactic nucleus Messier 87 takes the value which maximizes the ergospheric volume of the Kerr spacetime, we find the results compatible with the recent observations obtained by high-resolution interferometry on the origin of the jet, which would be located inside the innermost stable circular orbit diameter. Moreover, we find that a flow of unbound geodesics issued from the ergoregion is able to frame the best fits at large scales recently obtained for describing the observed profile of the relativistic jet launched from this central engine.
Single scale cluster expansions with applications to many Boson and unbounded spin systems
NASA Astrophysics Data System (ADS)
Lohmann, Martin
2015-06-01
We develop a cluster expansion to show exponential decay of correlations for quite general single scale spin systems, as they arise in lattice quantum field theory and discretized functional integral representations for observables of quantum statistical mechanics. We apply our results to the small field approximation to the coherent state correlation functions of the grand canonical Bose gas at negative chemical potential, constructed by Balaban et al. [Ann. Henri Poincaré 11, 151-350 (2010c)], and to N component unbounded spin systems with repulsive two body interaction and massive, possibly complex, covariance. Our cluster expansion is derived by a single application of the Brydges-Kennedy-Abdesselam-Rivasseau interpolation formula.
NASA Astrophysics Data System (ADS)
Aspon, Siti Zulaiha; Murid, Ali Hassan Mohamed; Rahmat, Hamisan
2014-07-01
This research is about computing the Green's functions on unbounded doubly connected regions by using the method of boundary integral equation. The method depends on solving an exterior Dirichlet problem. The Dirichlet problem is then solved using a uniquely solvable Fredholm integral equation on the boundary of the region. The kernel of this integral equation is the generalized Neumann kernel. The method for solving this integral equation is by using the Nyström method with trapezoidal rule to discretize it to a linear system. The linear system is then solved by the Gaussian elimination method. Mathematica plots of Green's functions for several test regions are also presented.
Steady flow for shear thickening fluids in domains with unbounded sections
NASA Astrophysics Data System (ADS)
Dias, Gilberlandio J.
2017-02-01
We solve the stationary Stokes and Navier-Stokes equations for non-Newtonian incompressible fluids with shear dependent viscosity in domains with outlets containing unbounded cross sections, in the case of shear thickening viscosity. The flux assumes arbitrary given values and the growth of the cross sections are analyzed under different convergence hypotheses, inclusive the growth of Dirichlet's integral of the velocity field is deeply related the convergence hypotheses of such sections. We extend the results of the section 4 of [12, Ladyzhenskaya and Solonnikov] (for Newtonian fluids) to non-Newtonian fluids using the techniques found in [3, Dias and Santos].
A Fourier-based elliptic solver for vortical flows with periodic and unbounded directions
NASA Astrophysics Data System (ADS)
Chatelain, Philippe; Koumoutsakos, Petros
2010-04-01
We present a computationally efficient, adaptive solver for the solution of the Poisson and Helmholtz equation used in flow simulations in domains with combinations of unbounded and periodic directions. The method relies on using FFTs on an extended domain and it is based on the method proposed by Hockney and Eastwood for plasma simulations. The method is well-suited to problems with dynamically growing domains and in particular flow simulations using vortex particle methods. The efficiency of the method is demonstrated in simulations of trailing vortices.
The Small-Mass Limit for Langevin Dynamics with Unbounded Coefficients and Positive Friction
NASA Astrophysics Data System (ADS)
Herzog, David P.; Hottovy, Scott; Volpe, Giovanni
2016-05-01
A class of Langevin stochastic differential equations is shown to converge in the small-mass limit under very weak assumptions on the coefficients defining the equation. The convergence result is applied to three physically realizable examples where the coefficients defining the Langevin equation for these examples grow unboundedly either at a boundary, such as a wall, and/or at the point at infinity. This unboundedness violates the assumptions of previous limit theorems in the literature. The main result of this paper proves convergence for such examples.
Single scale cluster expansions with applications to many Boson and unbounded spin systems
Lohmann, Martin
2015-06-15
We develop a cluster expansion to show exponential decay of correlations for quite general single scale spin systems, as they arise in lattice quantum field theory and discretized functional integral representations for observables of quantum statistical mechanics. We apply our results to the small field approximation to the coherent state correlation functions of the grand canonical Bose gas at negative chemical potential, constructed by Balaban et al. [Ann. Henri Poincaré 11, 151–350 (2010c)], and to N component unbounded spin systems with repulsive two body interaction and massive, possibly complex, covariance. Our cluster expansion is derived by a single application of the Brydges-Kennedy-Abdesselam-Rivasseau interpolation formula.
NASA Technical Reports Server (NTRS)
Rosen, I. G.
1988-01-01
An abstract approximation and convergence theory for the closed-loop solution of discrete-time linear-quadratic regulator problems for parabolic systems with unbounded input is developed. Under relatively mild stabilizability and detectability assumptions, functional analytic, operator techniques are used to demonstrate the norm convergence of Galerkin-based approximations to the optimal feedback control gains. The application of the general theory to a class of abstract boundary control systems is considered. Two examples, one involving the Neumann boundary control of a one-dimensional heat equation, and the other, the vibration control of a cantilevered viscoelastic beam via shear input at the free end, are discussed.
Generalized parton distributions in nuclei
Vadim Guzey
2009-12-01
Generalized parton distributions (GPDs) of nuclei describe the distribution of quarks and gluons in nuclei probed in hard exclusive reactions, such as e.g. deeply virtual Compton scattering (DVCS). Nuclear GPDs and nuclear DVCS allow us to study new aspects of many traditional nuclear effects (nuclear shadowing, EMC effect, medium modifications of the bound nucleons) as well as to access novel nuclear effects. In my talk, I review recent theoretical progress in the area of nuclear GPDs.
Exotic Orbital Modes in Nuclei
NASA Astrophysics Data System (ADS)
von Neumann-Cosel, P.
2003-06-01
Experimental evidence for two types of collective excitations in nuclei generated by orbital motion is discussed, viz. a magnetic quadrupole twist mode observed in 180° electron scattering experiments and a toroidal electric dipole mode. The latter may be a source of low-energy pygmy dipole resonances observed in many nuclei. This is discussed in detail for the example of 208Pb based on the recent finding of a resonance at particle threshold in a high-resolution (γ, γ') experiment.
NASA Technical Reports Server (NTRS)
Sykes, Mark V.; Walker, Russell G.
1992-01-01
The icy-conglomerate model of comet nuclei has dominated all others since its introduction. It provided a basis for understanding the non-gravitational motions of comets which had perplexed dynamicists up to that time, and provided a focus for understanding cometary composition and origin. The image of comets as dirty snowballs was quickly adopted. Comet nuclei including their trail mass loss rates and refractory to volatile mass ratios are described.
Plant Nuclei Move to Escape Ultraviolet-Induced DNA Damage and Cell Death.
Iwabuchi, Kosei; Hidema, Jun; Tamura, Kentaro; Takagi, Shingo; Hara-Nishimura, Ikuko
2016-02-01
A striking feature of plant nuclei is their light-dependent movement. In Arabidopsis (Arabidopsis thaliana) leaf mesophyll cells, the nuclei move to the side walls of cells within 1 to 3 h after blue-light reception, although the reason is unknown. Here, we show that the nuclear movement is a rapid and effective strategy to avoid ultraviolet B (UVB)-induced damages. Mesophyll nuclei were positioned on the cell bottom in the dark, but sudden exposure of these cells to UVB caused severe DNA damage and cell death. The damage was remarkably reduced in both blue-light-treated leaves and mutant leaves defective in the actin cytoskeleton. Intriguingly, in plants grown under high-light conditions, the mesophyll nuclei remained on the side walls even in the dark. These results suggest that plants have two strategies for reducing UVB exposure: rapid nuclear movement against acute exposure and nuclear anchoring against chronic exposure.
Optimal ultraviolet wavelength for in vivo photoacoustic imaging of cell nuclei.
Yao, Da-Kang; Chen, Ruimin; Maslov, Konstantin; Zhou, Qifa; Wang, Lihong V
2012-05-01
In order to image noninvasively cell nuclei in vivo without staining, we have developed ultraviolet photoacoustic microscopy (UV-PAM), in which ultraviolet light excites nucleic acids in cell nuclei to produce photoacoustic waves. Equipped with a tunable laser system, the UV-PAM was applied to in vivo imaging of cell nuclei in small animals. We found that 250 nm was the optimal wavelength for in vivo photoacoustic imaging of cell nuclei. The optimal wavelength enables UV-PAM to image cell nuclei using as little as 2 nJ laser pulse energy. Besides the optimal wavelength, application of a wavelength between 245 and 275 nm can produce in vivo images of cell nuclei with specific, positive, and high optical contrast.
Unbound Excited States of the N = 16 Closed Shell Nucleus 24O
NASA Astrophysics Data System (ADS)
Rogers, W. F.; MoNA Collaboration
2015-10-01
The energies of two low-lying neutron-unbound excited states of 24O, which were populated by proton-knockout reactions on 26F, have been measured using the MoNA and LISA arrays in combination with the Sweeper Magnet at the Coupled Cyclotron Facility at the NSCL using invariant mass spectroscopy. The current measurement confirms for the first time the separate identity of 2+ and (1+) neutron-unbound excited states in 24O with decay energies 0.51(5) MeV state and 1.20(7) MeV, respectively, to the 23O ground state. These measured decay energies are consistent with two previous lower resolution measurements to within 2 σ. The level energies for the two states are computed using the decay energies and the 1-neutron separation energy for 24O, resulting in 4.70(15) MeV for the 2+ state and 5.39(16) MeV for the (1+) state. Errors in the level energies are dominated by uncertainty in the 24O neutron separation energy, underscoring the need for a higher resolution 24O ground state mass measurement. Results will be compared with 3 phenomenological and 2 ab initio model calculations. Work Supported by NSF Grants PHY-0922335, PHY-0922409, PHY-0922446, PHY-0922462, PHY-0922473, PHY-0922537, PHY-0922559, PHY-0922622, PHY-0922794, PHY-0969173, PHY-1101745, PHY-1205357, PHY- 1205537.
Unbounded Immersed Interface solver, also for use in Vortex Particle-Mesh methods
NASA Astrophysics Data System (ADS)
Marichal, Yves; Chatelain, Philippe; Winckelmans, Gregoire
2012-11-01
We present a new and efficient algorithm to solve the 2-D Poisson equation in unbounded domain and with complex inner boundaries. It is based on an efficient combination of two components: the Immersed Interface method to enforce the boundary condition on each inner boundary (here using solely 1-D stencil corrections) and the James-Lackner algorithm to compute the outer boundary condition consistent with the unbounded domain solution. The algorithm is here implemented using second order finite differences and is particularized to the computation of potential flow past solid bodies. It is validated, by means of grid convergence studies, on the flow past multiple bodies (some also with circulation). The results confirm the second order accuracy everywhere. The algorithm is self consistent as ``all is done on the grid'' (thus without using a Vortex Panel boundary element method in addition to the grid). The next aim of this work is then to integrate this algorithm in the Vortex Particle-Mesh (VPM) method for the computation of unsteady viscous flows, with boundary layers, detached shear layers and wakes. Preliminary results of the combined methods will also be presented. Research Fellow (PhD student) of the F.R.S.-FNRS of Belgium.
NASA Astrophysics Data System (ADS)
Sharma, Mukul M.; Malhotra, Sahil
2012-11-01
An experimental study is performed to understand and quantify settling velocity of spherical particles in unbounded and confined surfactant-based shear thinning viscoelastic fluids. Experimental data is presented to show that elastic effects can increase or decrease the settling velocity of particles, even in the creeping flow regime. A significant drag reduction occurs with increase in Weissenberg number. This is followed by a transition to increasing drag at higher Weissenberg numbers. A new correlation is presented for the sphere settling velocity in unbounded viscoelastic fluids as a function of the fluid rheology and the proppant properties. The wall factors for sphere settling velocities in viscoelastic fluids confined between solid parallel plates are calculated from experimental measurements made over a range of Weissenberg numbers. Results indicate that elasticity reduces the effect of the confining walls and this reduction is more pronounced at higher ratios of the particle diameter to spacing between the walls. Shear thinning behavior of fluids is observed to reduce the retardation effect of the confining walls. A new empirical correlation for wall factors for spheres settling in a viscoelastic fluid confined between two parallel walls is presented.
Gamma Decay of Unbound Neutron-Hole States in ^{133}Sn.
Vaquero, V; Jungclaus, A; Doornenbal, P; Wimmer, K; Gargano, A; Tostevin, J A; Chen, S; Nácher, E; Sahin, E; Shiga, Y; Steppenbeck, D; Taniuchi, R; Xu, Z Y; Ando, T; Baba, H; Garrote, F L Bello; Franchoo, S; Hadynska-Klek, K; Kusoglu, A; Liu, J; Lokotko, T; Momiyama, S; Motobayashi, T; Nagamine, S; Nakatsuka, N; Niikura, M; Orlandi, R; Saito, T; Sakurai, H; Söderström, P A; Tveten, G M; Vajta, Zs; Yalcinkaya, M
2017-05-19
Excited states in the nucleus ^{133}Sn, with one neutron outside the double magic ^{132}Sn core, were populated following one-neutron knockout from a ^{134}Sn beam on a carbon target at relativistic energies at the Radioactive Isotope Beam Factory at RIKEN. Besides the γ rays emitted in the decay of the known neutron single-particle states in ^{133}Sn additional γ strength in the energy range 3.5-5.5 MeV was observed for the first time. Since the neutron-separation energy of ^{133}Sn is low, S_{n}=2.402(4) MeV, this observation provides direct evidence for the radiative decay of neutron-unbound states in this nucleus. The ability of electromagnetic decay to compete successfully with neutron emission at energies as high as 3 MeV above threshold is attributed to a mismatch between the wave functions of the initial and final states in the latter case. These findings suggest that in the region southeast of ^{132}Sn nuclear structure effects may play a significant role in the neutron versus γ competition in the decay of unbound states. As a consequence, the common neglect of such effects in the evaluation of the neutron-emission probabilities in calculations of global β-decay properties for astrophysical simulations may have to be reconsidered.
Multiple μ-stability of neural networks with unbounded time-varying delays.
Wang, Lili; Chen, Tianping
2014-05-01
In this paper, we are concerned with a class of recurrent neural networks with unbounded time-varying delays. Based on the geometrical configuration of activation functions, the phase space R(n) can be divided into several Φη-type subsets. Accordingly, a new set of regions Ωη are proposed, and rigorous mathematical analysis is provided to derive the existence of equilibrium point and its local μ-stability in each Ωη. It concludes that the n-dimensional neural networks can exhibit at least 3(n) equilibrium points and 2(n) of them are μ-stable. Furthermore, due to the compatible property, a set of new conditions are presented to address the dynamics in the remaining 3(n)-2(n) subset regions. As direct applications of these results, we can get some criteria on the multiple exponential stability, multiple power stability, multiple log-stability, multiple log-log-stability and so on. In addition, the approach and results can also be extended to the neural networks with K-level nonlinear activation functions and unbounded time-varying delays, in which there can store (2K+1)(n) equilibrium points, (K+1)(n) of them are locally μ-stable. Numerical examples are given to illustrate the effectiveness of our results.
Gamma Decay of Unbound Neutron-Hole States in 133Sn
NASA Astrophysics Data System (ADS)
Vaquero, V.; Jungclaus, A.; Doornenbal, P.; Wimmer, K.; Gargano, A.; Tostevin, J. A.; Chen, S.; Nácher, E.; Sahin, E.; Shiga, Y.; Steppenbeck, D.; Taniuchi, R.; Xu, Z. Y.; Ando, T.; Baba, H.; Garrote, F. L. Bello; Franchoo, S.; Hadynska-Klek, K.; Kusoglu, A.; Liu, J.; Lokotko, T.; Momiyama, S.; Motobayashi, T.; Nagamine, S.; Nakatsuka, N.; Niikura, M.; Orlandi, R.; Saito, T.; Sakurai, H.; Söderström, P. A.; Tveten, G. M.; Vajta, Zs.; Yalcinkaya, M.
2017-05-01
Excited states in the nucleus 133Sn, with one neutron outside the double magic 132Sn core, were populated following one-neutron knockout from a 134Sn beam on a carbon target at relativistic energies at the Radioactive Isotope Beam Factory at RIKEN. Besides the γ rays emitted in the decay of the known neutron single-particle states in 133Sn additional γ strength in the energy range 3.5-5.5 MeV was observed for the first time. Since the neutron-separation energy of 133Sn is low, Sn=2.402 (4 ) MeV , this observation provides direct evidence for the radiative decay of neutron-unbound states in this nucleus. The ability of electromagnetic decay to compete successfully with neutron emission at energies as high as 3 MeV above threshold is attributed to a mismatch between the wave functions of the initial and final states in the latter case. These findings suggest that in the region southeast of 132Sn nuclear structure effects may play a significant role in the neutron versus γ competition in the decay of unbound states. As a consequence, the common neglect of such effects in the evaluation of the neutron-emission probabilities in calculations of global β -decay properties for astrophysical simulations may have to be reconsidered.
Lim, Koeun; Wang, Wei; Merfeld, Daniel M
2017-07-26
Humans can subjectively yet quantitatively assess choice confidence based on perceptual precision even when a perceptual decision is made without an immediate reward or feedback. However, surprisingly little is known about choice confidence. Here we investigate the dynamics of choice confidence by merging two parallel conceptual frameworks of decision-making, signal detection theory and sequential analyses (i.e., drift diffusion modeling). Specifically, in order to capture end-point statistics of binary choice and confidence, we built on a previous study that defined choice confidence in terms of psychophysics derived from signal detection theory. At the same time, we augmented this mathematical model to include accumulator dynamics of a drift-diffusion model to characterize the time-dependency of the choice behaviors in a standard forced-choice paradigm in which stimulus duration is controlled by the operator. Human subjects performed a subjective visual vertical task, simultaneously reporting binary orientation choice and probabilistic confidence. Both binary choice and confidence experimental data displayed statistics and dynamics consistent with both signal detection theory and evidence accumulation, respectively. Specifically, the computational simulations showed that the unbounded evidence accumulator model fits the confidence data better than the classical bounded model, while bounded and unbounded models were indistinguishable for binary choice data. These results suggest that the brain can utilize mechanisms consistent with signal detection theory - especially when judging confidence without time pressure. Copyright © 2017, Journal of Neurophysiology.
NASA Astrophysics Data System (ADS)
Chen, Wen-Yau; Lai, Jeng-You; Young, D. L.
2010-11-01
Asymptotic and transient stability analyses of unbounded uniform granular shear flow at high solids volume fractions were carried out in the paper, based on a model composed of the viscoplastic constitutive law [P. Jop, Y. Forterre, and O. Pouliquen, Nature (London) 441, 727 (2006)] and the dilatancy law [O. Pouliquen et al., J. Stat. Mech.: Theory Exp. (2006) P07020]. We refer to this model as the VPDL (meaning of the "viscoplastic and dilatancy laws") thereinafter. In this model, dense granular flows were treated as a viscoplastic fluid with a Drucker-Prager-like yielding criterion. We compared our results to those obtained using the frictional-kinetic model (FKM) [M. Alam and P. R. Nott, J. Fluid Mech. 343, 267 (1997)]. Our main result is that unbounded uniform dense granular shear flows are always asymptotically stable at large time based on the VPDL model, at least for two-dimensional perturbations. This is valid for disturbances of layering modes (i.e., the perturbations whose wavenumber vectors are aligned along the transverse coordinate) as well as for nonlayering modes (the streamwise component of the wavenumber vector is nonzero). By contrast, layering modes can be unstable based on the FKM constitutive laws. Interestingly, in the framework of the VPDL, the analysis shows that significant transient growth may occur owing to the non-normality of the linear system, although disturbances eventually decay at large time.
Note on a modified return period scale for upper-truncated unbounded flood distributions
NASA Astrophysics Data System (ADS)
Bardsley, Earl
2017-01-01
Probability distributions unbounded to the right often give good fits to annual discharge maxima. However, all hydrological processes are in reality constrained by physical upper limits, though not necessarily well defined. A result of this contradiction is that for sufficiently small exceedance probabilities the unbounded distributions anticipate flood magnitudes which are impossibly large. This raises the question of whether displayed return period scales should, as is current practice, have some given number of years, such as 500 years, as the terminating rightmost tick-point. This carries the implication that the scale might be extended indefinitely to the right with a corresponding indefinite increase in flood magnitude. An alternative, suggested here, is to introduce a sufficiently high upper truncation point to the flood distribution and modify the return period scale accordingly. The rightmost tick-mark then becomes infinity, corresponding to the upper truncation point discharge. The truncation point is likely to be set as being above any physical upper bound and the return period scale will change only slightly over all practical return periods of operational interest. The rightmost infinity tick point is therefore proposed, not as an operational measure, but rather to signal in flood plots that the return period scale does not extend indefinitely to the right.
Generation of high-energy neutron beam by fragmentation of relativistic heavy nuclei
NASA Astrophysics Data System (ADS)
Yurevich, Vladimir
2016-09-01
The phenomenon of multiple production of neutrons in reactions with heavy nuclei induced by high-energy protons and light nuclei is analyzed using a Moving Source Model. The Lorentz transformation of the obtained neutron distributions is used to study the neutron characteristics in the inverse kinematics where relativistic heavy nuclei bombard a light-mass target. The neutron beam generated at 0∘has a Gaussian shape with a maximum at the energy of the projectile nucleons and an energy resolution σE/E < 4% above 6 GeV.
Reflection asymmetric shapes in nuclei
Ahmad, I.; Carpenter, M.P.; Emling, H.; Holzmann, R.; Janssens, R.V.F.; Khoo, T.L.; Moore, E.F.; Morss, L.R.; Durell, J.L.; Fitzgerald, J.B.; Mowbary, A.S.; Hotchkiss, M.A.; Phillips, W.R.; Drigert, M.W.; Ye, D.; Benet, P.; Manchester Univ. . Dept. of Physics; EG and G Idaho, Inc., Idaho Falls, ID; Notre Dame Univ., IN; Purdue Univ., Lafayette, IN )
1989-01-01
Experimental data show that there is no even-even nucleus with a reflection asymmetric shape in its ground state. Maximum octupole- octupole correlations occur in nuclei in the mass 224 (N{approximately}134, Z{approximately}88) region. Parity doublets, which are the characteristic signature of octupole deformation, have been observed in several odd mass Ra, Ac and Pa nuclei. Intertwined negative and positive parity levels have been observed in several even-even Ra and Th nuclei above spin {approximately}8{Dirac h}. In both cases, the opposite parity states are connected by fast El transitions. In some medium-mass nuclei intertwined negative and positive parity levels have also been observed above spin {approximately}7{Dirac h}. The nuclei which exhibit octupole deformation in this mass region are {sup 144}Ba, {sup 146}Ba and {sub 146}Ce; {sup 142}Ba, {sup 148}Ce, {sup 150}Ce and {sup 142}Xe do not show these characteristics. No case of parity doublet has been observed in the mass 144 region. 32 refs., 16 figs., 1 tab.
Kadmensky, S. G. Titova, L. V.; Bulychev, A. O.
2015-07-15
An analysis of basicmechanisms of binary and ternary fission of nuclei led to the conclusion that true ternary and quaternary fission of nuclei has a sequential two-step (three-step) character, where, at the first step, a fissile nucleus emits a third light particle (third and fourth light particles) under shakeup effects associated with a nonadiabatic character of its collective deformation motion, whereupon the residual nucleus undergoes fission to two fission fragments. Owing to this, the formulas derived earlier for the widths with respect to sequential two- and three-step decays of nuclei in constructing the theory of two-step twoproton decays and multistep decays in chains of genetically related nuclei could be used to describe the relative yields and angular and energy distributions of third and fourth light particles emitted in (α, α), (t, t), and (α, t) pairs upon the true quaternary spontaneous fission of {sup 252}Cf and thermal-neutron-induced fission of {sup 235}U and {sup 233}U target nuclei. Mechanisms that explain a sharp decrease in the yield of particles appearing second in time and entering into the composition of light-particle pairs that originate from true quaternary fission of nuclei in relation to the yields of analogous particles in true ternary fission of nuclei are proposed.
Improved variational wave functions for few-body nuclei
Wiringa, R.B.; Arriaga, A.; Pandharipande, V.R.
1995-08-01
We continued to work on improvements to our variational wave functions for use in Monte Carlo calculations of few-body nuclei. These trial functions include central, spin, isospin, tensor, and spin-orbit two-body correlations and three-body correlations for the three-nucleon potential. In the last two years we studied a variety of extra three-body correlations. Our search for possible forms was guided by comparisons made with 34-channel Faddeev wave functions provided by the Los Alamos-Iowa group. The new trial functions reduce the discrepancy with exact Faddeev calculations in {sup 3}H and Green`s Function Monte Carlo (GFMC) calculations in {sup 4}He by about 40%. This work is now being written up for publication. We hope to use similar comparisons with GFMC calculations in the six-body nuclei to find further improvements for the light p-shell nuclei, where the variational wave functions are not as good.
Coupled cluster calculations of neutron-rich nuclei
NASA Astrophysics Data System (ADS)
Hagen, Gaute
2016-09-01
In this talk I will present recent highlights from ab initio computations of atomic nuclei using coupled-cluster methods with state-of-the-art interactions from chiral effective field theory (EFT). The recent progress in computing nuclei from scratch is based on new optimizations of interactions from chiral EFT, and ab initio methods with a polynomial computational cost together with available super computing resources. The physics advancements I will discuss include: (i) accurate nuclear binding energies and radii of light and medium-mass nuclei, (ii) the neutron distribution and electric dipole polarizability of the nucleus 48Ca, (iii) and the structure of the rare nucleus 78Ni from first principles. All these quantities are currently targeted by precision measurements worldwide.
Microscopic Shell Model Calculations for sd-Shell Nuclei
NASA Astrophysics Data System (ADS)
Barrett, Bruce R.; Dikmen, Erdal; Maris, Pieter; Shirokov, Andrey M.; Smirnova, Nadya A.; Vary, James P.
Several techniques now exist for performing detailed and accurate calculations of the structure of light nuclei, i.e., A ≤ 16. Going to heavier nuclei requires new techniques or extensions of old ones. One of these is the so-called No Core Shell Model (NCSM) with a Core approach, which involves an Okubo-Lee-Suzuki (OLS) transformation of a converged NCSM result into a single major shell, such as the sd-shell. The obtained effective two-body matrix elements can be separated into core and single-particle (s.p.) energies plus residual two-body interactions, which can be used for performing standard shell-model (SSM) calculations. As an example, an application of this procedure will be given for nuclei at the beginning ofthe sd-shell.
Nuclei at extreme conditions. A relativistic study
Afanasjev, Anatoli
2014-11-14
The major goals of the current project were further development of covariant density functional theory (CDFT), better understanding of its features, its application to different nuclear structure and nuclear astrophysics phenomena and training of graduate and undergraduate students. The investigations have proceeded in a number of directions which are discussed in detail in the part “Accomplishments” of this report. We have studied the role of isovector and isoscalar proton-neutron pairings in rotating nuclei; based on available experimental data it was concluded that there are no evidences for the existence of isoscalar proton-neutron pairing. Generalized theoretical approach has been developed for pycnonuclear reaction rates in the crust of neutron stars and interior of white dwarfs. Using this approach, extensive database for considerable number of pycnonuclear reactions involving stable and neutron-rich light nuclei has been created; it can be used in future for the study of various nuclear burning phenomena in different environments. Time-odd mean fields and their manifestations in terminating states, non-rotating and rotating nuclei have been studied in the framework of covariant density functional theory. Contrary to non-relativistic density functional theories these fields, which are important for a proper description of nuclear systems with broken time-reversal symmetry, are uniquely defined in the CDFT framework. Hyperdeformed nuclear shapes (with semi-axis ratio 2.5:1 and larger) have been studied in the Z = 40-58 part of nuclear chart. We strongly believe that such shapes could be studied experimentally in the future with full scale GRETA detector.
Large and round tumor nuclei in osteosarcoma: good clinical outcome
de Andrea, Carlos E; Petrilli, Antonio Sergio; Jesus-Garcia, Reynaldo; Bleggi-Torres, Luiz F; Alves, Maria Teresa S
2011-01-01
Osteosarcoma is the most frequent primary malignant bone tumor. Distinct histological features are distinguishable based on the morphology of the tumor. Differences in nuclei size and shape are often observed in osteosarcoma reflecting its broad histopathological heterogeneity. This study explores the relevance of two nuclear parameters in osteosarcoma: large area and round shape. Computerized nuclear morphometry was performed in 56 conventional osteosarcoma preoperative biopsies. The mean patient follow-up time was 35.1 months. Based on the nuclear area, no significant difference (P = 0.09) in overall survival between patients with large (> 42.5 μm2) and small (< 42.5 μm2) tumor nuclei was found. However, when cases with large and round nuclei were analyzed jointly (> 42.5 μm2 and coefficient of nuclear roundness > 0.7), these two parameters together were likely to be a predictive factor (P = 0.05). Osteosarcoma patients with large and round tumor nuclei had a better outcome than patients with small and polymorphic (ovoid or spindle-shaped) nuclei. In this study, nuclear morphometry proved to be a useful tool to shed light on the biology of osteosarcoma showing that some morphometric parameters can be easily applied to help identifying patients with a good prognosis. PMID:21326812
Octupole shapes in heavy nuclei
Ahmad, I.
1994-08-01
Theoretical calculations and measurements show the presence of strong octupole correlations in thecyround states and low-lying states of odd-mass and odd-odd nuclei in the RaPa region. Evidence for octupole correlations is provided by the observation of parity doublets and reductions in M1 matrix elements, decoupling parameters, and Coriolis matrix elements Involving high-j states. Enhancement of E1 transition rates has also been observed for some of the octupole deformed nuclei. The most convincing argument for octupole deformation is provided by the similarities of the reduced alpha decay rates to the two members of parity doublets.
Chromatin structure in barley nuclei.
Mithieux, G; Roux, B
1983-10-03
In order to study the chromatin structure of a higher plant we used a high-yield method, which allows one to obtain up to 10(9) nuclei/kg fresh barley leaves. Significant amounts of low-ionic-strength-soluble chromatin can be extracted from these nuclei. Physicochemical properties were examined and discussed. Electric birefringence allowed us to observe the same transition in electro-optical properties as has been observed for animal chromatin, and suggested the existence of a symetrical structure occurring for approximately six nucleosomes. Circular dichroism showed that barley oligonucleosomes exhibit a higher molar ellipticity at 282 nm than total soluble chromatin and than their animal counterparts.
Observations of anthropogenic cloud condensation nuclei
NASA Technical Reports Server (NTRS)
Hudson, James G.
1990-01-01
Cloud Condensation Nuclei (CCN) concentrations and spectral measurements obtained with the DRI instantaneous CCN spectrometer (Hudson, 1989) over the last few years are presented. The climatic importance of cloud microphysics has been pointed out. The particles which affect cloud microphysics are cloud condensation nuclei (CCN). The commonly-observed order of magnitude difference in cloud droplet concentrations between maritime and continental air masses (i.e., Squires, 1958) was determined to be caused by systematic differences in the concentrations of CCN between continental and maritime air masses (e.g., Twomey and Wojciechowski, 1969). Twomey (1977) first pointed out that cloud microphysics also affects the radiative properties of clouds. Thus continental and anthropogenic CCN could affect global temperature. Resolution of this Twomey effect requires answers to two questions - whether antropogenic CCN are a significant contribution to atmospheric CCN, and whether they are actually affecting cloud microphysics to an extent which is of climatic importance. The reasons for the contrast between continental and maritime CCN concentration are not understood. The question of the relative importance of anthropogenic CCN is addressed. These observations should shed light on this complex question although further research is being conducted in order to produce more quantitative answers. Accompanying CN measurements made with a TSI 3020 condensation nucleus (CN) counter are also presented.
Temperatures within comet nuclei.
Squyres, S W; McKay, C P; Reynolds, R T
1985-12-10
We have performed a theoretical study of temperatures beneath the surface of a comet's nucleus. We solve the one-dimensional heat conduction equation for the outer portion of the comet. The upper boundary condition of the model is given by energy balance at the surface of the nucleus, including conduction of heat inward, radiation, insolation as modified by the coma, and sublimation. Our coma model assumes single scattering and includes attenuation of direct sunlight by dust grains, scattering of light onto the nucleus, and infrared radiation by dust grains. The lower boundary condition is zero net heat flux around an orbit. The thermal conductivity expression for the nucleus includes direct conduction at grain boundaries, radiative conduction, and Knudsen flow vapor diffusion. The thermal diffusivity of the nucleus and the resultant temperature profiles are shown to be strongly dependent on the physical properties of the material, including porosity, pore size, and compaction. The temperature profiles and the equilibrium temperature deep within the comet also depend on the functional relationship between thermal conductivity and temperature; the highest deep equilibrium temperatures are found for models where the thermal conductivity increases strongly with increasing temperature. The dependence of temperatures on the albedo and thermal emissivity of the nucleus is also calculated, as well as the variation of temperature with latitude for a variety of pole orientations. The effect of a dust mantle on subsurface temperatures is also investigated. All calculations are presented for short-period comets with orbits that make them accessible for exploration by spacecraft rendezvous. In situ measurements of the thermal profile in the upper meter of a comet nucleus can substantially constrain the thermal diffusivity of the material, which in turn can provide significant information about the physical properties of the nucleus.
Unbound excited states of the N =16 closed shell nucleus 24O
NASA Astrophysics Data System (ADS)
Rogers, W. F.; Garrett, S.; Grovom, A.; Anthony, R. E.; Aulie, A.; Barker, A.; Baumann, T.; Brett, J. J.; Brown, J.; Christian, G.; DeYoung, P. A.; Finck, J. E.; Frank, N.; Hamann, A.; Haring-Kaye, R. A.; Hinnefeld, J.; Howe, A. R.; Islam, N. T.; Jones, M. D.; Kuchera, A. N.; Kwiatkowski, J.; Lunderberg, E. M.; Luther, B.; Meyer, D. A.; Mosby, S.; Palmisano, A.; Parkhurst, R.; Peters, A.; Smith, J.; Snyder, J.; Spyrou, A.; Stephenson, S. L.; Strongman, M.; Sutherland, B.; Taylor, N. E.; Thoennessen, M.
2015-09-01
Two low-lying neutron-unbound excited states of 24O, populated by proton-knockout reactions on 26F, have been measured using the MoNA and LISA arrays in combination with the Sweeper Magnet at the Coupled Cyclotron Facility at the NSCL using invariant mass spectroscopy. The current measurement confirms the separate identity of two states with decay energies 0.51(5) MeV and 1.20(7) MeV, and provides support for theoretical model calculations, which predict a 2+ first excited state and a 1+ higher-energy state. The measured excitation energies for these states, 4.70(15) MeV for the 2+ level and 5.39(16) MeV for the 1+ level, are consistent with previous lower-resolution measurements, and are compared with five recent model predictions.
Partial-Nodes-Based State Estimation for Complex Networks With Unbounded Distributed Delays.
Liu, Yurong; Wang, Zidong; Yuan, Yuan; Alsaadi, Fuad E
2017-09-07
In this brief, the new problem of partial-nodes-based (PNB) state estimation problem is investigated for a class of complex network with unbounded distributed delays and energy-bounded measurement noises. The main novelty lies in that the states of the complex network are estimated through measurement outputs of a fraction of the network nodes. Such fraction of the nodes is determined by either the practical availability or the computational necessity. The PNB state estimator is designed such that the error dynamics of the network state estimation is exponentially ultimately bounded in the presence of measurement errors. Sufficient conditions are established to ensure the existence of the PNB state estimators and then the explicit expression of the gain matrices of such estimators is characterized. When the network measurements are free of noises, the main results specialize to the case of exponential stability for error dynamics. Numerical examples are presented to verify the theoretical results.
Nucleus ^{26}O: A Barely Unbound System beyond the Drip Line.
Kondo, Y; Nakamura, T; Tanaka, R; Minakata, R; Ogoshi, S; Orr, N A; Achouri, N L; Aumann, T; Baba, H; Delaunay, F; Doornenbal, P; Fukuda, N; Gibelin, J; Hwang, J W; Inabe, N; Isobe, T; Kameda, D; Kanno, D; Kim, S; Kobayashi, N; Kobayashi, T; Kubo, T; Leblond, S; Lee, J; Marqués, F M; Motobayashi, T; Murai, D; Murakami, T; Muto, K; Nakashima, T; Nakatsuka, N; Navin, A; Nishi, S; Otsu, H; Sato, H; Satou, Y; Shimizu, Y; Suzuki, H; Takahashi, K; Takeda, H; Takeuchi, S; Togano, Y; Tuff, A G; Vandebrouck, M; Yoneda, K
2016-03-11
The unbound nucleus ^{26}O has been investigated using invariant-mass spectroscopy following one-proton removal reaction from a ^{27}F beam at 201 MeV/nucleon. The decay products, ^{24}O and two neutrons, were detected in coincidence using the newly commissioned SAMURAI spectrometer at the RIKEN Radioactive Isotope Beam Factory. The ^{26}O ground-state resonance was found to lie only 18±3(stat)±4(syst) keV above threshold. In addition, a higher lying level, which is most likely the first 2^{+} state, was observed for the first time at 1.28_{-0.08}^{+0.11} MeV above threshold. Comparison with theoretical predictions suggests that three-nucleon forces, pf-shell intruder configurations, and the continuum are key elements to understanding the structure of the most neutron-rich oxygen isotopes beyond the drip line.
Nucleus 26O: A Barely Unbound System beyond the Drip Line
NASA Astrophysics Data System (ADS)
Kondo, Y.; Nakamura, T.; Tanaka, R.; Minakata, R.; Ogoshi, S.; Orr, N. A.; Achouri, N. L.; Aumann, T.; Baba, H.; Delaunay, F.; Doornenbal, P.; Fukuda, N.; Gibelin, J.; Hwang, J. W.; Inabe, N.; Isobe, T.; Kameda, D.; Kanno, D.; Kim, S.; Kobayashi, N.; Kobayashi, T.; Kubo, T.; Leblond, S.; Lee, J.; Marqués, F. M.; Motobayashi, T.; Murai, D.; Murakami, T.; Muto, K.; Nakashima, T.; Nakatsuka, N.; Navin, A.; Nishi, S.; Otsu, H.; Sato, H.; Satou, Y.; Shimizu, Y.; Suzuki, H.; Takahashi, K.; Takeda, H.; Takeuchi, S.; Togano, Y.; Tuff, A. G.; Vandebrouck, M.; Yoneda, K.
2016-03-01
The unbound nucleus 26O has been investigated using invariant-mass spectroscopy following one-proton removal reaction from a 27F beam at 201 MeV /nucleon . The decay products, 2424 and two neutrons, were detected in coincidence using the newly commissioned SAMURAI spectrometer at the RIKEN Radioactive Isotope Beam Factory. The 26O ground-state resonance was found to lie only 18 ±3 (stat )±4 (syst ) keV above threshold. In addition, a higher lying level, which is most likely the first 2+ state, was observed for the first time at 1.28-0.08+0.11 MeV above threshold. Comparison with theoretical predictions suggests that three-nucleon forces, p f -shell intruder configurations, and the continuum are key elements to understanding the structure of the most neutron-rich oxygen isotopes beyond the drip line.
Stellar dynamics. The fastest unbound star in our Galaxy ejected by a thermonuclear supernova.
Geier, S; Fürst, F; Ziegerer, E; Kupfer, T; Heber, U; Irrgang, A; Wang, B; Liu, Z; Han, Z; Sesar, B; Levitan, D; Kotak, R; Magnier, E; Smith, K; Burgett, W S; Chambers, K; Flewelling, H; Kaiser, N; Wainscoat, R; Waters, C
2015-03-06
Hypervelocity stars (HVSs) travel with velocities so high that they exceed the escape velocity of the Galaxy. Several acceleration mechanisms have been discussed. Only one HVS (US 708, HVS 2) is a compact helium star. Here we present a spectroscopic and kinematic analysis of US 708. Traveling with a velocity of ~1200 kilometers per second, it is the fastest unbound star in our Galaxy. In reconstructing its trajectory, the Galactic center becomes very unlikely as an origin, which is hardly consistent with the most favored ejection mechanism for the other HVSs. Furthermore, we detected that US 708 is a fast rotator. According to our binary evolution model, it was spun-up by tidal interaction in a close binary and is likely to be the ejected donor remnant of a thermonuclear supernova. Copyright © 2015, American Association for the Advancement of Science.
Complete stability of cellular neural networks with unbounded time-varying delays.
Wang, Lili; Chen, Tianping
2012-12-01
In this paper, we are concerned with the delayed cellular neural networks (DCNNs) in the case that the time-varying delays are unbounded. Under some conditions, it shows that the DCNNs can exhibit 3(n) equilibrium points. Then, we track the dynamics of u(t)(t>0) in two cases with respect to different types of subset regions in which u(0) is located. It concludes that every solution trajectory u(t) would converge to one of the equilibrium points despite the time-varying delays, that is, the delayed cellular neural networks are completely stable. The method is novel and the results obtained extend the existing ones. In addition, two illustrative examples are presented to verify the effectiveness of our results.
Construction of dynamics and time-ordered exponential for unbounded non-symmetric Hamiltonians
Futakuchi, Shinichiro; Usui, Kouta
2014-06-15
We prove under certain assumptions that there exists a solution of the Schrödinger or the Heisenberg equation of motion generated by a linear operator H acting in some complex Hilbert space H, which may be unbounded, not symmetric, or not normal. We also prove that, under the same assumptions, there exists a time evolution operator in the interaction picture and that the evolution operator enjoys a useful series expansion formula. This expansion is considered to be one of the mathematically rigorous realizations of so-called “time-ordered exponential,” which is familiar in the physics literature. We apply the general theory to prove the existence of dynamics for the mathematical model of Quantum Electrodynamics quantized in the Lorenz gauge, the interaction Hamiltonian of which is not even symmetric or normal.
μ-Stability of Nonlinear Positive Systems With Unbounded Time-Varying Delays.
Chen, Tianping; Liu, Xiwei
2016-03-11
The stability of the zero solution plays an important role in the investigation of positive systems. In this brief, we discuss the μ-stability of positive nonlinear systems with unbounded time-varying delays. The system is modeled by the continuous-time ordinary differential equation. Under some assumptions on the nonlinear functions, such as homogeneous, cooperative, and nondecreasing, we propose a novel transform, by which the nonlinear system reduces to a new system. Thus, we analyze its dynamics, which can simplify the nonlinear homogenous functions with respect to the arbitrary dilation map to those with respect to the standard dilation map. We finally get some new criteria for the global μ-stability taking the degree into consideration. A numerical example is given to demonstrate the validity of obtained results.
A combined ADER-DG and PML approach for simulating wave propagation in unbounded domains
NASA Astrophysics Data System (ADS)
Amler, Thomas G.; Hoteit, Ibrahim; Alkhalifah, Tariq A.
2012-09-01
In this work, we present a numerical approach for simulating wave propagation in unbounded domains which combines discontinuous Galerkin methods with arbitrary high order time integration (ADER-DG) and a stabilized modification of perfectly matched layers (PML). Here, the ADER-DG method is applied to Bérenger's formulation of PML. The instabilities caused by the original PML formulation are treated by a fractional step method that allows to monitor whether waves are damped in PML region. In grid cells where waves are amplified by the PML, the contribution of damping terms is neglected and auxiliary variables are reset. Results of 2D simulations in acoustic media with constant and discontinuous material parameters are presented to illustrate the performance of the method.
NASA Technical Reports Server (NTRS)
Gibson, J. S.; Rosen, I. G.
1987-01-01
The approximation of optimal discrete-time linear quadratic Gaussian (LQG) compensators for distributed parameter control systems with boundary input and unbounded measurement is considered. The approach applies to a wide range of problems that can be formulated in a state space on which both the discrete-time input and output operators are continuous. Approximating compensators are obtained via application of the LQG theory and associated approximation results for infinite dimensional discrete-time control systems with bounded input and output. Numerical results for spline and modal based approximation schemes used to compute optimal compensators for a one dimensional heat equation with either Neumann or Dirichlet boundary control and pointwise measurement of temperature are presented and discussed.
Breakdown of the Z=8 Shell Closure in Unbound {sup 12}O and its Mirror Symmetry
Suzuki, D.; Iwasaki, H.; Beaumel, D.; Assie, M.; Blumenfeld, Y.; De Sereville, N.; Franchoo, S.; Guillot, J.; Hammache, F.; Marechal, F.; Ramus, A.; Scarpaci, J.-A.; Stefan, I.; Nalpas, L.; Pollacco, E.; Drouart, A.; Gillibert, A.; Lapoux, V.; Mougeot, X.
2009-10-09
An excited state in the proton-rich unbound nucleus {sup 12}O was identified at 1.8(4) MeV via missing-mass spectroscopy with the {sup 14}O(p,t) reaction at 51 AMeV. The spin-parity of the state was determined to be 0{sup +} or 2{sup +} by comparing the measured differential cross sections with distorted-wave calculations. The lowered location of the excited state in {sup 12}O indicates the breakdown of the major shell closure at Z=8 near the proton drip line. This demonstrates the persistence of mirror symmetry in the disappearance of the magic number 8 between {sup 12}O and its mirror partner {sup 12}Be.
Unbounded number of channel uses may be required to detect quantum capacity.
Cubitt, Toby; Elkouss, David; Matthews, William; Ozols, Maris; Pérez-García, David; Strelchuk, Sergii
2015-03-31
Transmitting data reliably over noisy communication channels is one of the most important applications of information theory, and is well understood for channels modelled by classical physics. However, when quantum effects are involved, we do not know how to compute channel capacities. This is because the formula for the quantum capacity involves maximizing the coherent information over an unbounded number of channel uses. In fact, entanglement across channel uses can even increase the coherent information from zero to non-zero. Here we study the number of channel uses necessary to detect positive coherent information. In all previous known examples, two channel uses already sufficed. It might be that only a finite number of channel uses is always sufficient. We show that this is not the case: for any number of uses, there are channels for which the coherent information is zero, but which nonetheless have capacity.
NASA Technical Reports Server (NTRS)
Gibson, J. S.; Rosen, I. G.
1988-01-01
The approximation of optimal discrete-time linear quadratic Gaussian (LQG) compensators for distributed parameter control systems with boundary input and unbounded measurement is considered. The approach applies to a wide range of problems that can be formulated in a state space on which both the discrete-time input and output operators are continuous. Approximating compensators are obtained via application of the LQG theory and associated approximation results for infinite dimensional discrete-time control systems with bounded input and output. Numerical results for spline and modal based approximation schemes used to compute optimal compensators for a one-dimensional heat equation with either Neumann or Dirichlet boundary control and pointwise measurement of temperature are presented and discussed.
Solutions to higher-order anisotropic parabolic equations in unbounded domains
NASA Astrophysics Data System (ADS)
Kozhevnikova, L. M.; Leont'ev, A. A.
2014-01-01
The paper is devoted to a certain class of doubly nonlinear higher-order anisotropic parabolic equations. Using Galerkin approximations it is proved that the first mixed problem with homogeneous Dirichlet boundary condition has a strong solution in the cylinder D=(0,\\infty)\\times\\Omega, where \\Omega\\subset R^n, n\\geq 3, is an unbounded domain. When the initial function has compact support the highest possible rate of decay of this solution as t\\to \\infty is found. An upper estimate characterizing the decay of the solution is established, which is close to the lower estimate if the domain is sufficiently 'narrow'. The same authors have previously obtained results of this type for second order anisotropic parabolic equations. Bibliography: 29 titles.
Unbounded keyhole collapse and bubble formation during pulsed laser interaction with liquid zinc
NASA Astrophysics Data System (ADS)
Kaplan, Alexander F. H.; Mizutani, Masami; Katayama, Seiji; Matsunawa, Akira
2002-06-01
Suppression of pore defects in keyhole laser spot welding demands for a theoretical description of the fundamental process. Investigating the unbounded keyhole collapse in liquid Zn instead of a solid provided a simplified situation offering several advantages. Improved high speed x-ray transmission imaging due to an enlarged keyhole in the absence of violent melt motion was enabled, which also facilitated the development of a semi-analytical mathematical model. Good correspondence between the experimentally and theoretically obtained transient keyhole and bubble shape permitted physical analysis by the model. Characteristic timescales were identified for post-vaporization, vapour relaxation, cooling, collapse, bubble contraction, oscillations and buoyancy. Recondensation due to rapid cooling turns out to be responsible for shielding gas flow into the keyhole, finally maintaining a spherical bubble. Creation of a convergent keyhole is a possibility to avoid bubbles.
The effect of surface tension on steadily translating bubbles in an unbounded Hele-Shaw cell
NASA Astrophysics Data System (ADS)
Green, Christopher C.; Lustri, Christopher J.; McCue, Scott W.
2017-05-01
New numerical solutions to the so-called selection problem for one and two steadily translating bubbles in an unbounded Hele-Shaw cell are presented. Our approach relies on conformal mapping which, for the two-bubble problem, involves the Schottky-Klein prime function associated with an annulus. We show that a countably infinite number of solutions exist for each fixed value of dimensionless surface tension, with the bubble shapes becoming more exotic as the solution branch number increases. Our numerical results suggest that a single solution is selected in the limit that surface tension vanishes, with the scaling between the bubble velocity and surface tension being different to the well-studied problems for a bubble or a finger propagating in a channel geometry.