Science.gov

Sample records for rotating nuclei studied

  1. Theoretical study of the nuclear spin-molecular rotation coupling for relativistic electrons and non-relativistic nuclei.

    PubMed

    Aucar, Ignacio A; Gómez, Sergio S; Ruiz de Azúa, Martín C; Giribet, Claudia G

    2012-05-28

    A theoretical study of the relation between the relativistic formulation of the nuclear magnetic shielding and spin-rotation tensors is presented. To this end a theoretical expression of the relativistic spin-rotation tensor is formulated, considering a molecular Hamiltonian of relativistic electrons and non-relativistic nuclei. Molecular rotation effects are introduced considering the terms of the Born-Oppenheimer decomposition, which couple the electrons and nuclei dynamics. The loss of the simple relation linking both spectral parameters in the non-relativistic formulation is further analyzed carrying out a perturbative expansion of relativistic effects by means of the linear response within the elimination of the small component approach. It is concluded that relativistic effects on the spin-rotation tensor are less important than those of the nuclear magnetic shielding tensor.

  2. A high-speed target-rotation system (taro) for the study of short-lived nuclei

    NASA Astrophysics Data System (ADS)

    Miyatake, H.; Hama, H.; Kamiya, T.; Yoshii, M.; Shinozuka, T.; Fujioka, M.

    1986-05-01

    We describe the design and performance of a high-speed target-rotation system for the study of nuclei far from stability, by which targets can be transported to the detector position in 60 ms after irradiation (90° rotation). The rotor movement and the cyclotron beam pulsing, as well as the data acquisition, are controlled by a microcomputer. Using this device 54Co (T {1}/{2} = 193 ms) and 58Cu (T {1}/{2} = 3.2 s) were observed in a test experiment with a transport efficiency of 71 and 98%, respectively (180° rotation).

  3. Shell model for warm rotating nuclei

    SciTech Connect

    Matsuo, M.; Yoshida, K.; Dossing, T.

    1996-12-31

    Utilizing a shell model which combines the cranked Nilsson mean-field and the residual surface and volume delta two-body forces, the authors discuss the onset of rotational damping in normal- and super-deformed nuclei. Calculation for a typical normal deformed nucleus {sup 168}Yb indicates that the rotational damping sets in at around 0.8 MeV above the yrast line, and about 30 rotational bands of various length exists at a given rotational frequency, in overall agreement with experimental findings. It is predicted that the onset of rotational damping changes significantly in different superdeformed nuclei due to the variety of the shell gaps and single-particle orbits associated with the superdeformed mean-field.

  4. Nuclear vibrations and rotations of like nucleons in the same shell in even-even nuclei

    SciTech Connect

    Osman, A.; Allam, M.A.

    1987-01-01

    The vibrational and rotational motions in even nuclei are considered. A microscopic study of these motions leads to a relation between the vibrational motion in spherical nuclei and the rotational motion in deformed nuclei. Nuclei with like nucleons in the same shell are considered. The quadrupole two-body interactions are used in the large single j-shell of even nuclei. The energies and transition operators of nuclei in the nuclear rotational region are calculated using this microscopic method. Quadrupole moments are also calculated. These calculations are compared with the rotational model of the aligned coupling scheme. The present calculations are in good agreement with previous calculations.

  5. A Study of the Jacobi Shape Transition in Light, Fast Rotating Nuclei with the EUROBALL IV, HECTOR and EUCLIDES Arrays

    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.

  6. A Study of the Jacobi Shape Transition in Light, Fast Rotating Nuclei with the EUROBALL IV, HECTOR and EUCLIDES Arrays

    SciTech Connect

    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.

  7. Rotation of warm nuclei and superdeformation

    NASA Astrophysics Data System (ADS)

    Leoni, S.; Lopez-Martens, A.

    2016-06-01

    The Niels Bohr Institute (NBI) has played a leading role in the development of nuclear spectroscopy at high spin and more particularly the study of rotational motion. Indeed, it laid the theoretical foundation stone and contributed to the birth of the workhorse of the field: the Compton-suppressed Ge array. In this article, we will focus, with special emphasis on the contribution of the NBI, on the properties of rotational motion at high excitation energy and on chaotic phenomena associated with nuclear superdeformation.

  8. Covariant density functional theory: Global performance and rotating nuclei

    NASA Astrophysics Data System (ADS)

    Ray, Debisree

    Covariant density functional theory (CDFT) is a modern theoretical tool for the description of nuclear structure physics. Here different physical properties of the ground and excited states in atomic nuclei have been investigated within the CDFT framework employing three major classes of the state-of-the-art covariant energy density functionals. The global performance of CEDFs for even-even nuclei are investigated and the systematic theoretical uncertainties are estimated within the set of four CEDFs in known regions of the nuclear chart and their propagation towards the neutron drip line. Large-scale axial relativistic Hartree-Bogoliubov (RHB) calculations are performed for even-even nuclei to calculate different ground state observables. The predictions for the two-neutron drip line are also compared in a systematic way with the non-relativistic results. CDFT has been applied for systematic study of extremely deformed, rotating N ˜ Z nuclei of the A ˜ 40 mass region. At spin zero such structures are located at high energies which prevents their experimental observation. The rotation acts as a tool to bring these exotic shapes down to the yrast line so that their observation could become possible with a future generation detectors such as GRETA or AGATA. The major physical observables of such structures, the underlying single-particle structure and the spins at which they become yrast or near yrast are defined. The search for the fingerprints of clusterization and molecular structures is performed and the configurations with such features are discussed. CDFT has been applied to study fission barriers of superheavy nuclei and related systematic theoretical uncertainties in the predictions of inner fission barrier heights in super- heavy elements. Systematic uncertainties are substantial in superheavy elements and their behavior as a function of proton and neutron numbers contains a large random component. The benchmarking of the functionals to the experimental

  9. How do nuclei really vibrate or rotate

    SciTech Connect

    Andresen, H.G.; Kunz, J.; Mosel, U.; Mueller, M.; Schuh, A.; Wust, U.

    1983-01-01

    By means of the adiabatic cranking model the properties of the current and velocity fields of nuclear quadrupole vibrations for even-even nuclei in the rare-earth region are investigated. BCS correlated wave functions based on the Nilsson single particle Hamiltonian have been used. The current fields are analyzed in terms of vector spherical harmonics. The realistic microscopic currents show a vortex structure not present in the classical irrotational flow. The microscopic origin of the vortex structure is investigated.

  10. Microscopic formulation of the interacting boson model for rotational nuclei

    SciTech Connect

    Nomura, Kosuke; Shimizu, Noritaka; Otsuka, Takaharu; Guo, Lu

    2011-04-15

    We propose a novel formulation of the interacting boson model (IBM) for rotational nuclei with axially symmetric, strong deformation. The intrinsic structure represented by the potential-energy surface (PES) of a given multinucleon system has a certain similarity to that of the corresponding multiboson system. Based on this feature, one can derive an appropriate boson Hamiltonian, as already reported. This prescription, however, has a major difficulty in the rotational spectra of strongly deformed nuclei: the bosonic moment of inertia is significantly smaller than the corresponding nucleonic one. We present that this difficulty originates in the difference between the rotational response of a nucleon system and that of the corresponding boson system, and could arise even if the PESs of the two systems were identical. We further suggest that the problem can be solved by implementing the L{center_dot}L term into the IBM Hamiltonian, with the coupling constant derived from the cranking approach of Skyrme mean-field models. The validity of the method is confirmed for rare-earth and actinoid nuclei, as their experimental rotational yrast bands are reproduced nicely.

  11. Order-to-chaos transition in rotational nuclei

    SciTech Connect

    Stephens, F.S.; Deleplanque, M.A.; Lee, I.Y.; Macchiavelli, A.O.; Ward, D.; Fallon, P.; Cromaz, M.; Clark, R.M.; Descovich, M.; Diamond, R.M.; Rodriguez-Vieitez, E.

    2004-05-13

    The authors have studied the narrow (valley-ridge) structure in the {gamma}-ray spectrum following a heavy-ion fusion reaction that produces several ytterbium nuclei. The intensity of this structure can be quantitatively related to the average chaotic behavior in these nuclei and they have traced this behavior from nearly fully ordered to nearly fully chaotic.

  12. Random Disruption of Cometary Nuclei by Rotational Spin-Up

    NASA Astrophysics Data System (ADS)

    Weissman, P. R.; Richardson, D. C.; Bottke, W. F.

    2003-05-01

    Both long- and short-period comets have been observed to randomly disrupt (split) during passage through the planetary region. These disruption events range from small fragments separating from the primary nucleus to complete disruption and disintegration of the nucleus. These events do not show any correlation with time from perihelion passage or distance above or below the ecliptic plane (Weissman, A&A 85, 191, 1980). A variety of mechanisms have been proposed to explain disruption events, including: impacts, gas release from volatile pockets, the amorphous-crystalline water ice phase transition, and rotational spin-up. We believe the last mechanism may provide the most plausible explanation for nucleus disruption events. This view is supported by the rotation period versus axial ratio plot of Lowry & Weissman (Icarus, in press, 2003), which shows an apparent lack of nuclei with rotation periods < 5 hours, corresponding to a bulk density lower limit of ˜ 0.6 g cm-3 for strengthless rubble piles. We have investigated this problem using two different methods. First we developed an analytic model of the expected rotational spin-up (and spin-down) of typical cometary nuclei due to asymmetric forces from jetting of volatiles on the nucleus surface. Next, we modeled the spin-up of rubble-pile nuclei with discrete active surface areas, using an N-body code, pkdgrav (Richardson et al., Icarus 143, 45, 2000). The code treats gravity and impacts between particles as hard-sphere interactions with adjustable collisional dissipation. The jets are modeled as an optionally varying force acting on one or more particles. Results will be reported. This work was funded in part by the NASA Planetary Geology & Geophysics and Origins programs.

  13. Harmonic oscillator in quantum rotational spectra: Molecules and nuclei

    NASA Technical Reports Server (NTRS)

    Pavlichenkov, Igor M.

    1995-01-01

    The mapping of a rotational dynamics on a harmonic oscillator is considered. The method used for studying the stabilization of the rigid top rotation around the intermediate moment of inertial axix by orbiting particle is described.

  14. Nonadiabatic quasiparticle approach for rotation-particle coupling in triaxial odd-A nuclei

    NASA Astrophysics Data System (ADS)

    Modi, Swati; Patial, M.; Arumugam, P.; Maglione, E.; Ferreira, L. S.

    2017-02-01

    We discuss the formulation of a nonadiabatic approach to study the rotational states in triaxially deformed odd-A nuclei. The rotation-particle coupling is treated microscopically by coupling the triaxial rotor states of the even-even core with the states of the valence particle in order to obtain the matrix elements of the odd-A system. We arrive at a nonadiabatic quasiparticle approach where the rotational states can have contributions from various quasiparticle states near the Fermi level. We bring out the advantages of this approach over the conventional particle rotor model with a fixed or variable moment of inertia. One clear evidence favoring our approach is the rotation alignment phenomenon which is demonstrated in the case of 137Pm. We discuss our results for 136Nd and 137Pm, and justify that this approach is suitable also for studying nuclei away from stability.

  15. Dynamic-angle spinning and double rotation of quadrupolar nuclei

    SciTech Connect

    Mueller, K.T. California Univ., Berkeley, CA . Dept. of Chemistry)

    1991-07-01

    Nuclear magnetic resonance (NMR) spectroscopy of quadrupolar nuclei is complicated by the coupling of the electric quadrupole moment of the nucleus to local variations in the electric field. The quadrupolar interaction is a useful source of information about local molecular structure in solids, but it tends to broaden resonance lines causing crowding and overlap in NMR spectra. Magic- angle spinning, which is routinely used to produce high resolution spectra of spin-{1/2} nuclei like carbon-13 and silicon-29, is incapable of fully narrowing resonances from quadrupolar nuclei when anisotropic second-order quadrupolar interactions are present. Two new sample-spinning techniques are introduced here that completely average the second-order quadrupolar coupling. Narrow resonance lines are obtained and individual resonances from distinct nuclear sites are identified. In dynamic-angle spinning (DAS) a rotor containing a powdered sample is reoriented between discrete angles with respect to high magnetic field. Evolution under anisotropic interactions at the different angles cancels, leaving only the isotropic evolution of the spin system. In the second technique, double rotation (DOR), a small rotor spins within a larger rotor so that the sample traces out a complicated trajectory in space. The relative orientation of the rotors and the orientation of the larger rotor within the magnetic field are selected to average both first- and second-order anisotropic broadening. The theory of quadrupolar interactions, coherent averaging theory, and motional narrowing by sample reorientation are reviewed with emphasis on the chemical shift anisotropy and second-order quadrupolar interactions experienced by half-odd integer spin quadrupolar nuclei. The DAS and DOR techniques are introduced and illustrated with application to common quadrupolar systems such as sodium-23 and oxygen-17 nuclei in solids.

  16. Quantal rotation and its coupling to intrinsic motion in nuclei

    NASA Astrophysics Data System (ADS)

    Nakatsukasa, Takashi; Matsuyanagi, Kenichi; Matsuzaki, Masayuki; Shimizu, Yoshifumi R.

    2016-07-01

    Symmetry breaking is an important concept in nuclear physics and other fields of physics. Self-consistent coupling between the mean-field potential and the single-particle motion is a key ingredient in the unified model of Bohr and Mottelson, which could lead to a deformed nucleus as a consequence of spontaneous breaking of the rotational symmetry. Some remarks on the finite-size quantum effects are given. In finite nuclei, the deformation inevitably introduces the rotation as a symmetry-restoring collective motion (Anderson-Nambu-Goldstone mode), and the rotation affects the intrinsic motion. In order to investigate the interplay between the rotational and intrinsic motions in a variety of collective phenomena, we use the cranking prescription together with the quasiparticle random phase approximation (QRPA). At low spin, the coupling effect can be seen in the generalized intensity relation. A feasible quantization of the cranking model is presented, which provides a microscopic approach to the higher-order intensity relation. At high spin, the semiclassical cranking prescription works well. We discuss properties of collective vibrational motions under rapid rotation and/or large deformation. The superdeformed shell structure plays a key role in emergence of a new soft mode which could lead to instability toward the {K}π ={1}- octupole shape. A wobbling mode of excitation, which is a clear signature of the triaxiality, is discussed in terms of a microscopic point of view. A crucial role played by the quasiparticle alignment is presented.

  17. Competition in rotation-alignment between high-j neutrons and protons in transfermium nuclei

    SciTech Connect

    Al-Khudair, Falih; Long Guilu; Sun Yang

    2009-03-15

    The study of rotation-alignment of quasiparticles probes sensitively the properties of high-j intruder orbits. The distribution of very-high-j orbits, which are consequences of the fundamental spin-orbit interaction, links with the important question of single-particle levels in superheavy nuclei. With the deformed single-particle states generated by the standard Nilsson potential, we perform Projected Shell Model calculations for transfermium nuclei where detailed spectroscopy experiments are currently possible. Specifically, we study the systematical behavior of rotation-alignment and associated band-crossing phenomenon in Cf, Fm, and No isotopes. Neutrons and protons from the high-j orbits are found to compete strongly in rotation-alignment, which gives rise to testable effects. Observation of these effects will provide direct information on the single-particle states in the heaviest nuclear mass region.

  18. Evolution of Binary Supermassive Black Holes in Rotating Nuclei

    NASA Astrophysics Data System (ADS)

    Rasskazov, Alexander; Merritt, David

    2017-03-01

    The interaction of a binary supermassive black hole with stars in a galactic nucleus can result in changes to all the elements of the binary’s orbit, including the angles that define its orientation. If the nucleus is rotating, the orientation changes can be large, causing large changes in the binary’s orbital eccentricity as well. We present a general treatment of this problem based on the Fokker–Planck equation for f, defined as the probability distribution for the binary’s orbital elements. First- and second-order diffusion coefficients are derived for the orbital elements of the binary using numerical scattering experiments, and analytic approximations are presented for some of these coefficients. Solutions of the Fokker–Planck equation are then derived under various assumptions about the initial rotational state of the nucleus and the binary hardening rate. We find that the evolution of the orbital elements can become qualitatively different when we introduce nuclear rotation: (1) the orientation of the binary’s orbit evolves toward alignment with the plane of rotation of the nucleus and (2) binary orbital eccentricity decreases for aligned binaries and increases for counteraligned ones. We find that the diffusive (random-walk) component of a binary’s evolution is small in nuclei with non-negligible rotation, and we derive the time-evolution equations for the semimajor axis, eccentricity, and inclination in that approximation. The aforementioned effects could influence gravitational wave production as well as the relative orientation of host galaxies and radio jets.

  19. Coulomb energy differences in analog rotational bands of f7/2-shell nuclei

    NASA Astrophysics Data System (ADS)

    Lenzi, S. M.; Mǎrginean, N.; Napoli, D. R.; Ur, C. A.; Zuker, A. P.; Axiotis, M.; Brandolini, F.; de Angelis, G.; Farnea, E.; Gadea, A.; Martínez-Pinedo, G.; Poves, A.; Sánchez-Solano, J.

    2002-04-01

    Recent experimental and shell model studies of isospin symmetry along the ground state rotational bands in the mirror nuclei 50Fe and 50Cr are presented. This is the heaviest T=1 mirror pair studied so far at high spin. It is shown that the Coulomb energy differences provide a good tool to probe the alignment mechanism at the backbending and that they also give information about the evolution of yrast radii as a function of the angular momentum. .

  20. Nuclei at extreme conditions. A relativistic study

    SciTech Connect

    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.

  1. Study of strange nuclei

    SciTech Connect

    Chrien, R.E.

    1982-12-08

    A brief history of the discovery of hypernuclei is given and some recent hypernuclei studies are described. Topics include the study of p-shell hypernuclei, /sup 12/C (K/sup -/, ..pi../sup -/) experiment, and hypernuclear gamma rays. 13 references. (WHK)

  2. The rotation of mouse myoblast nuclei is dependent on substrate elasticity.

    PubMed

    Hickey, Ryan; Pelling, Andrew E

    2017-04-01

    The complex interplay of biochemical signaling and mechanical traction forces regulate the position of cellular nuclei. Although the phenomenon of nuclear rotation has been observed for many years, the influence of substrate elasticity was unknown. We discovered another layer of complexity to this phenomenon: nuclear rotation is dependent on substrate elasticity. Nuclear rotation is drastically reduced on physiologically relevant stiffnesses. Here, we studied nuclear rotation in mouse C2C12 myoblasts cultured on soft substrates designed to mimic resting tissue (∼26 kPa) and on hard glass substrates. We examined the roles of the actin and microtubule cytoskeleton on the presence and dynamics of nuclear rotation in these two different microenvironments. We demonstrated the clear dependence of nuclear rotation dynamics on matrix stiffness. These results will have important implications for the design of future studies of nuclear rotation and our understanding of the phenomenon as a whole. Unnaturally, hard substrates do not only fail to mimic the in vivo microenvironment, but can also induce cellular processes that would not normally occur in the natural cellular environment. © 2017 Wiley Periodicals, Inc.

  3. Rotational behavior of comet nuclei under gravitational perturbations

    NASA Technical Reports Server (NTRS)

    Oberti, Pascal; Bois, E.; Froeschle, Claude

    1992-01-01

    A dynamical qualitative study of the rotational motion for cometary-type bodies submitted to gravitational perturbations has been performed by numerical simulations, including the Sun and Jupiter's disturbing torques in the model. Results show small gravitational disturbing effects from the Sun on Halley-type orbits, as well as from Jupiter on most close-approach configurations. Only a very close-approach induces notable effects, presenting then some interesting sensitivity to initial conditions.

  4. Application of a two-parameter quantum algebra to rotational spectroscopy of nuclei

    NASA Astrophysics Data System (ADS)

    Barbier, R.; Kibler, M.

    1996-10-01

    A two-parameter quantum algebra Uqp( u2) is briefly investigated in this paper. The basic ingredients of a model based on the Uqp( u2) symmetry, the qp-rotator model, are presented in detail. Some general tendencies arising from the application of this model to the description of rotational bands of various atomic nuclei are summarized.

  5. Transition from collective to noncollective rotation at high spin in N approx. = 87 nuclei

    SciTech Connect

    Baktash, C.

    1982-01-01

    The systematics of the (E2) ..gamma.. ray transition energies and the available lifetime data are used to characterize the excitation modes of the light rare-earth nuclei (N greater than or equal to 82) at different spins. The results, which include our recently obtained data on /sup 149/Gd, /sup 154/Ho, /sup 155/Er, /sup 157/Yb and /sup 158/Yb nuclei, indicate that, at low spins, the nuclear excitation mode (shapes) change from single-particle excitations (weakly oblate) in N less than or equal to 85 nuclei to quasi-vibrational (soft triaxial) in N = 86, weakly rotational (prolate) in N = 87, and rotational (prolate) in the N greater than or equal to 88 systems. At higher angular momenta, all these nuclei show a general tendency to traverse the (epsilon,..gamma..) plane towards the oblate axis, and to eventually adopt the aligned coupling mode of excitation.

  6. Realistic description of rotational bands in rare earth nuclei by the angular-momentum-projected multicranked configuration-mixing method

    NASA Astrophysics Data System (ADS)

    Shimada, Mitsuhiro; Tagami, Shingo; Shimizu, Yoshifumi R.

    2016-04-01

    Recently we proposed a reliable method to describe the rotational band in a fully microscopic manner. The method has recourse to the configuration mixing of several cranked mean-field wave functions after the angular-momentum projection. By applying the method with the Gogny D1S force as an effective interaction, we investigate the moments of inertia of the ground state rotational bands in a number of selected nuclei in the rare earth region. As another application we try to describe, for the first time, the two-neutron aligned band in 164Er, which crosses the ground state band and becomes the yrast states at higher spins. Fairly good overall agreements with the experimental data are achieved; for nuclei, where the pairing correlations are properly described, the agreements are excellent. This confirms that the previously proposed method is really useful for the study of the nuclear rotational motion.

  7. PHYSICAL STUDIES OF ISOLATED EUCARYOTIC NUCLEI

    PubMed Central

    Olins, Donald E.; Olins, Ada L.

    1972-01-01

    The degree of chromatin condensation in isolated rat liver nuclei and chicken erythrocyte nuclei was studied by phase-contrast microscopy as a function of solvent pH, K+ and Mg++ concentrations Data were represented as "phase" maps, and standard solvent conditions selected that reproducibly yield granular, slightly granular, and homogeneous nuclei Nuclei in these various states were examined by ultraviolet absorption and circular dichroism (CD) spectroscopy, low-angle X-ray diffraction, electron microscopy, and binding capacity for ethidium bromide Homogeneous nuclei exhibited absorption and CD spectra resembling those of isolated nucleohistone. Suspensions of granular nuclei showed marked turbidity and absorption flattening, and a characteristic blue-shift of a crossover wavelength in the CD spectra. In all solvent conditions studied, except pH < 2 3, low-angle X-ray reflections characteristic of the native, presumably superhelical, nucleohistone were observed from pellets of intact nuclei. Threads (100–200 A diameter) were present in the condensed and dispersed phases of nuclei fixed under the standard solvent conditions, and examined in the electron microscope after thin sectioning and staining Nuclei at neutral pH, with different degrees of chromatin condensation, exhibited similar binding capacities for ethidium bromide. These data suggest a model that views chromatin condensation as a close packing of superhelical nucleohistone threads but still permits condensed chromatin to respond rapidly to alterations in solvent environment. PMID:4554987

  8. Emergence of rotational bands in ab initio no-core configuration interaction calculations of light nuclei

    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).

  9. Evolution of massive black hole binaries in rotating galactic nuclei: implications for gravitational wave detection

    NASA Astrophysics Data System (ADS)

    Rasskazov, Alexander; Merritt, David

    2017-01-01

    The subject of our study is a binary supermassive black hole (BSBH) in the center of a galactic nucleus. We model the evolution of its orbit due to interactions with the stars of the galaxy by means of 3-body scattering experiments. Our model includes a new degree of freedom - the orientation of the BSBH’s orbital plane - which is allowed to change due to interaction with the stars in a rotating nucleus. The binary’s eccentricity also evolves in an orientation-dependent manner. We find that the dynamics are qualitatively different compared with non-rotating nuclei: 1) The BSBH's orbital plane evolves toward alignment with the plane of rotation of the nucleus; 2) The BSBH’s eccentricity decreases for aligned BSBHs and increases for counter-aligned ones.We then apply our model to calculate the effects of stellar environment on the gravitational wave background spectrum produced by BSBHs. Using the results of recent N-body/Monte-Carlo simulations we account for different rates of stellar interaction in spherical, axisymmetric and triaxial galaxies. We also consider the possibility that SBH masses are systematically lower than usually assumed. The net result of the new physical mechanisms included here is a spectrum for the stochastic gravitational wave background that has a significantly lower amplitude than in previous treatments, which could explain the discrepancy that currently exists between the models and the upper limits set by pulsar timing array observations.

  10. On the dust zoning of rapidly rotating cometary nuclei

    NASA Technical Reports Server (NTRS)

    Houpis, H. L. F.; Mendis, D. A.

    1981-01-01

    The effects of nuclear rotation on the surface of a cometary nucleus (a comet at 1 AU that is H2O dominated and has a radius of 1 km) are considered. It is shown that this dust does not accumulate uniformly on the surface, which here is considered spherical. While dust particles in the two polar cap regions and an equatorial belt remain at rest on the surface, those in two midlatitude bands migrate toward the equator, stopping at the two low latitudes to form dust ridges. As the nucleus spins up, both the polar caps and the equatorial belt shrink in size, and the dust ridges move toward the equator, eventually spinning off the dust from the nucleus when the nuclear rotation period is less than about 3.3 hr. For larger particles for which the gas buoyancy is negligible, migration takes place only if the rotation period is not significantly larger than the critical value of 3.3 hr or if the surface friction is abnormally small.

  11. Exact diagonalization of the Bohr Hamiltonian for rotational nuclei: Dynamical {gamma} softness and triaxiality

    SciTech Connect

    Caprio, M. A.

    2011-06-15

    Detailed quantitative predictions are obtained for phonon and multiphonon excitations in well-deformed rotor nuclei within the geometric framework, by exact numerical diagonalization of the Bohr Hamiltonian in an SO(5) basis. Dynamical {gamma} deformation is found to significantly influence the predictions through its coupling to the rotational motion. Basic signatures for the onset of rigid triaxial deformation are also obtained.

  12. Evolution of massive black hole binaries in rotating stellar nuclei: Implications for gravitational wave detection

    NASA Astrophysics Data System (ADS)

    Rasskazov, Alexander; Merritt, David

    2017-04-01

    We compute the isotropic gravitational wave (GW) background produced by binary supermassive black holes (SBHs) in galactic nuclei. In our model, massive binaries evolve at early times via gravitational-slingshot interaction with nearby stars, and at later times by the emission of GWs. Our expressions for the rate of binary hardening in the "stellar" regime are taken from the recent work of Vasiliev et al., who show that in the nonaxisymmetric galaxies expected to form via mergers, stars are supplied to the center at high enough rates to ensure binary coalescence on Gyr timescales. We also include, for the first time, the extra degrees of freedom associated with evolution of the binary's orbital plane; in rotating nuclei, interaction with stars causes the orientation and the eccentricity of a massive binary to change in tandem, leading in some cases to very high eccentricities (e >0.9 ) before the binary enters the GW-dominated regime. We argue that previous studies have over-estimated the mean ratio of SBH mass to galaxy bulge mass by factors of 2-3. In the frequency regime currently accessible to pulsar timing arrays (PTAs), our assumptions imply a factor 2-3 reduction in the characteristic strain compared with the values computed in most recent studies, removing the tension that currently exists between model predictions and the nondetection of GWs.

  13. Modified particle-rotor model and low-lying rotational bands in odd-A triaxial nuclei

    NASA Astrophysics Data System (ADS)

    Modi, Swati; Patial, M.; Arumugam, P.; Maglione, E.; Ferreira, L. S.

    2017-09-01

    The low-lying rotational bands of triaxially deformed nuclei 137Pr, 137Pm and 139Eu are studied with a modified particle-rotor model following the nonadiabatic quasiparticle approach. The matrix elements of the odd-A nucleus are obtained in terms of a coupling matrix and the rotational energies of the even-even core. The spectra of the cores 136Ce, 136Nd and 138Sm indicate a strong influence of triaxial deformation and vibrational degrees of freedom. These properties are appropriately carried forward to the calculations for the odd-A nucleus. We demonstrate that the ground and side bands of the odd-A nucleus and its core can be explained with the same set of deformation parameters ({β }2, γ). We argue that this method could be useful in studying the low-lying states in exotic nuclei also.

  14. Properties of rotational bands at the spin limit in A {approximately} 50, A {approximately} 65 and A {approximately} 110 nuclei

    SciTech Connect

    Janzen, V.P.; Andrews, H.R.; Ball, G.C.

    1996-12-31

    There is now widespread evidence for the smooth termination of rotational bands in A {approx_equal} 110 nuclei at spins of 40-to-50{Dirac_h}s. The characteristics of these bands are compared to those of bands recently observed to high spin in {sup 64}Zn and {sup 48}Cr, studied with the 8{pi} {gamma}-ray spectrometer coupled to the Chalk River miniball charged-particle-detector array.

  15. Rotating reactor studies

    NASA Technical Reports Server (NTRS)

    Roberts, Glyn O.

    1991-01-01

    Undesired gravitational effects such as convection or sedimentation in a fluid can sometimes be avoided or decreased by the use of a closed chamber uniformly rotated about a horizontal axis. In a previous study, the spiral orbits of a heavy or buoyant particle in a uniformly rotating fluid were determined. The particles move in circles, and spiral in or out under the combined effects of the centrifugal force and centrifugal buoyancy. A optimization problem for the rotation rate of a cylindrical reactor rotated about its axis and containing distributed particles was formulated and solved. Related studies in several areas are addressed. A computer program based on the analysis was upgraded by correcting some minor errors, adding a sophisticated screen-and-printer graphics capability and other output options, and by improving the automation. The design, performance, and analysis of a series of experiments with monodisperse polystyrene latex microspheres in water were supported to test the theory and its limitations. The theory was amply confirmed at high rotation rates. However, at low rotation rates (1 rpm or less) the assumption of uniform solid-body rotation of the fluid became invalid, and there were increasingly strong secondary motions driven by variations in the mean fluid density due to variations in the particle concentration. In these tests the increase in the mean fluid density due to the particles was of order 0.015 percent. To a first approximation, these flows are driven by the buoyancy in a thin crescent-shaped depleted layer on the descending side of the rotating reactor. This buoyancy distribution is balanced by viscosity near the walls, and by the Coriolis force in the interior. A full analysis is beyond the scope of this study. Secondary flows are likely to be stronger for buoyant particles, which spiral in towards the neutral point near the rotation axis under the influence of their centrifugal buoyancy. This is because the depleted layer is

  16. Parsec-scale Faraday rotation and polarization of 20 active galactic nuclei jets

    NASA Astrophysics Data System (ADS)

    Kravchenko, E. V.; Kovalev, Y. Y.; Sokolovsky, K. V.

    2017-01-01

    We perform polarimetry analysis of 20 active galactic nuclei jets using the very long baseline array at 1.4, 1.6, 2.2, 2.4, 4.6, 5.0, 8.1, 8.4 and 15.4 GHz. The study allowed us to investigate linearly polarized properties of the jets at parsec scales: distribution of the Faraday rotation measure (RM) and fractional polarization along the jets, Faraday effects and structure of Faraday-corrected polarization images. Wavelength dependence of the fractional polarization and polarization angle is consistent with external Faraday rotation, while some sources show internal rotation. The RM changes along the jets, systematically increasing its value towards synchrotron self-absorbed cores at shorter wavelengths. The highest core RM reaches 16 900 rad m-2 in the source rest frame for the quasar 0952+179, suggesting the presence of highly magnetized, dense media in these regions. The typical RM of transparent jet regions has values of an order of a hundred rad m-2. Significant transverse RM gradients are observed in seven sources. The magnetic field in the Faraday screen has no preferred orientation, and is observed to be random or regular from source to source. Half of the sources show evidence for the helical magnetic fields in their rotating magneto-ionic media. At the same time jets themselves contain large-scale, ordered magnetic fields and tend to align its direction with the jet flow. The observed variety of polarized signatures can be explained by a model of spine-sheath jet structure.

  17. The fate of ultrahigh energy nuclei in the immediate environment of young fast-rotating pulsars

    SciTech Connect

    Kotera, Kumiko; Amato, Elena; Blasi, Pasquale E-mail: amato@arcetri.astro.it

    2015-08-01

    Young, fast-rotating neutron stars are promising candidate sources for the production of ultrahigh energy cosmic rays (UHECRs). The interest in this model has recently been boosted by the latest chemical composition measurements of cosmic rays, that seem to show the presence of a heavy nuclear component at the highest energies. Neutrons stars, with their metal-rich surfaces, are potentially interesting sources of such nuclei, but some open issues remain: 1) is it possible to extract these nuclei from the star's surface? 2) Do the nuclei survive the severe conditions present in the magnetosphere of the neutron star? 3) What happens to the surviving nuclei once they enter the wind that is launched outside the light cylinder? In this paper we address these issues in a quantitative way, proving that for the most reasonable range of neutron star surface temperatures (T<10{sup 7} K), a large fraction of heavy nuclei survive photo-disintegration losses. These processes, together with curvature losses and acceleration in the star's electric potential, lead to injection of nuclei with a chemical composition that is mixed, even if only iron is extracted from the surface. We show that under certain conditions the chemical composition injected into the wind region is compatible with that required in previous work based on purely phenomenological arguments (typically ∼50% protons, ∼30% CNO and ∼20% Fe), and provides a reasonable explanation of the mass abundance inferred from ultra high energy data.

  18. The fate of ultrahigh energy nuclei in the immediate environment of young fast-rotating pulsars

    NASA Astrophysics Data System (ADS)

    Kotera, Kumiko; Amato, Elena; Blasi, Pasquale

    2015-08-01

    Young, fast-rotating neutron stars are promising candidate sources for the production of ultrahigh energy cosmic rays (UHECRs). The interest in this model has recently been boosted by the latest chemical composition measurements of cosmic rays, that seem to show the presence of a heavy nuclear component at the highest energies. Neutrons stars, with their metal-rich surfaces, are potentially interesting sources of such nuclei, but some open issues remain: 1) is it possible to extract these nuclei from the star's surface? 2) Do the nuclei survive the severe conditions present in the magnetosphere of the neutron star? 3) What happens to the surviving nuclei once they enter the wind that is launched outside the light cylinder? In this paper we address these issues in a quantitative way, proving that for the most reasonable range of neutron star surface temperatures (T<107 K), a large fraction of heavy nuclei survive photo-disintegration losses. These processes, together with curvature losses and acceleration in the star's electric potential, lead to injection of nuclei with a chemical composition that is mixed, even if only iron is extracted from the surface. We show that under certain conditions the chemical composition injected into the wind region is compatible with that required in previous work based on purely phenomenological arguments (typically ~50% protons, ~30% CNO and ~20% Fe), and provides a reasonable explanation of the mass abundance inferred from ultra high energy data.

  19. Integration of vestibular and head movement signals in the vestibular nuclei during whole-body rotation

    NASA Technical Reports Server (NTRS)

    Gdowski, G. T.; McCrea, R. A.; Peterson, B. W. (Principal Investigator)

    1999-01-01

    Single-unit recordings were obtained from 107 horizontal semicircular canal-related central vestibular neurons in three alert squirrel monkeys during passive sinusoidal whole-body rotation (WBR) while the head was free to move in the yaw plane (2.3 Hz, 20 degrees /s). Most of the units were identified as secondary vestibular neurons by electrical stimulation of the ipsilateral vestibular nerve (61/80 tested). Both non-eye-movement (n = 52) and eye-movement-related (n = 55) units were studied. Unit responses recorded when the head was free to move were compared with responses recorded when the head was restrained from moving. WBR in the absence of a visual target evoked a compensatory vestibulocollic reflex (VCR) that effectively reduced the head velocity in space by an average of 33 +/- 14%. In 73 units, the compensatory head movements were sufficiently large to permit the effect of the VCR on vestibular signal processing to be assessed quantitatively. The VCR affected the rotational responses of different vestibular neurons in different ways. Approximately one-half of the units (34/73, 47%) had responses that decreased as head velocity decreased. However, the responses of many other units (24/73) showed little change. These cells had signals that were better correlated with trunk velocity than with head velocity. The remaining units had responses that were significantly larger (15/73, 21%) when the VCR produced a decrease in head velocity. Eye-movement-related units tended to have rotational responses that were correlated with head velocity. On the other hand, non-eye-movement units tended to have rotational responses that were better correlated with trunk velocity. We conclude that sensory vestibular signals are transformed from head-in-space coordinates to trunk-in-space coordinates on many secondary vestibular neurons in the vestibular nuclei by the addition of inputs related to head rotation on the trunk. This coordinate transformation is presumably important

  20. Integration of vestibular and head movement signals in the vestibular nuclei during whole-body rotation

    NASA Technical Reports Server (NTRS)

    Gdowski, G. T.; McCrea, R. A.; Peterson, B. W. (Principal Investigator)

    1999-01-01

    Single-unit recordings were obtained from 107 horizontal semicircular canal-related central vestibular neurons in three alert squirrel monkeys during passive sinusoidal whole-body rotation (WBR) while the head was free to move in the yaw plane (2.3 Hz, 20 degrees /s). Most of the units were identified as secondary vestibular neurons by electrical stimulation of the ipsilateral vestibular nerve (61/80 tested). Both non-eye-movement (n = 52) and eye-movement-related (n = 55) units were studied. Unit responses recorded when the head was free to move were compared with responses recorded when the head was restrained from moving. WBR in the absence of a visual target evoked a compensatory vestibulocollic reflex (VCR) that effectively reduced the head velocity in space by an average of 33 +/- 14%. In 73 units, the compensatory head movements were sufficiently large to permit the effect of the VCR on vestibular signal processing to be assessed quantitatively. The VCR affected the rotational responses of different vestibular neurons in different ways. Approximately one-half of the units (34/73, 47%) had responses that decreased as head velocity decreased. However, the responses of many other units (24/73) showed little change. These cells had signals that were better correlated with trunk velocity than with head velocity. The remaining units had responses that were significantly larger (15/73, 21%) when the VCR produced a decrease in head velocity. Eye-movement-related units tended to have rotational responses that were correlated with head velocity. On the other hand, non-eye-movement units tended to have rotational responses that were better correlated with trunk velocity. We conclude that sensory vestibular signals are transformed from head-in-space coordinates to trunk-in-space coordinates on many secondary vestibular neurons in the vestibular nuclei by the addition of inputs related to head rotation on the trunk. This coordinate transformation is presumably important

  1. A Uqp(u2) model for rotational bands of nuclei

    NASA Astrophysics Data System (ADS)

    Barbier, R.; Meyer, J.; Kibler, M.

    1994-01-01

    A rotational model is developed from a new version of the two-parameter quantum algebra $U_{qp}({\\rm u}_2)$. This model is applied to the description of some recent experimental data for the rotating superdeformed nuclei $^{192-194-196-198}{\\rm Pb}$ and $^{192-194 }{\\rm Hg}$. A comparison between the $U_{qp}({\\rm u}_2)$ model presented here and the Raychev-Roussev-Smirnov model with $U_{q }({\\rm su}_2)$ symmetry shows the relevance of the introduction of a second parameter of a ``quantum algebra'' type.

  2. Spin-rotation functions for 500-MeV protons scattered by UCa nuclei

    SciTech Connect

    Berezhnoi, Y.A.; Molev, A.S.; Pilipenko, V.V.; Soznik, A.P.

    1985-06-01

    The polarization characteristics in the elastic and inelastic scattering of 500-MeV protons by UCa nuclei are analyzed, using the theory of multiple diffraction scattering. The investigated proton-spin-rotation functions are very sensitive to the NN-amplitude parameters. A set of NN-amplitude parameters is found that correctly describes the set of measured observables. The analysis yields valuable information on the NN amplitude, especially on its spin-orbit part.

  3. Static and Statistical Properties of Hot Rotating Nuclei in a Macroscopic Temperature-Dependent Finite-Range Model

    SciTech Connect

    Ryabov, E.G.; Adeev, G.D.

    2005-09-01

    A macroscopic temperature-dependent model that takes into account nuclear forces of finite range is used to calculate the static and statistical properties of hot rotating compound nuclei. The level-density parameter is approximated by an expression of the leptodermous type. The resulting expansion coefficients are in good agreement with their counterparts proposed previously by A.V. Ignatyuk and his colleagues. The effect of taking simultaneously into account the temperature of a nucleus and its angular momentum on the quantities under study, such as the heights and positions of fission barriers and the effective moments of inertia of nuclei at the barrier, is considered, and the importance of doing this is demonstrated. The fissility parameter (Z{sup 2}/A){sub crit} and the position of the Businaro-Gallone point are studied versus temperature. It is found that, with increasing temperature, both parameters are shifted to the region of lighter nuclei. It is shown that the inclusion of temperature leads to qualitatively the same effects as the inclusion of the angular momentum of a nucleus, but, quantitatively, thermal excitation leads to smaller effects than rotational excitation.

  4. A microscopic derivation of nuclear collective rotation-vibration model and its application to nuclei

    SciTech Connect

    Gulshani, P.

    2016-07-07

    We derive a microscopic version of the successful phenomenological hydrodynamic model of Bohr-Davydov-Faessler-Greiner for collective rotation-vibration motion of an axially symmetric deformed nucleus. The derivation is not limited to small oscillation amplitude. The nuclear Schrodinger equation is canonically transformed to collective co-ordinates, which is then linearized using a constrained variational method. The associated constraints are imposed on the wavefunction rather than on the particle co-ordinates. The approach yields three self-consistent, time-reversal invariant, cranking-type Schrodinger equations for the rotation-vibration and intrinsic motions, and a self-consistency equation. For harmonic oscillator mean-field potentials, these equations are solved in closed forms for excitation energy, cut-off angular momentum, and other nuclear properties for the ground-state rotational band in some deformed nuclei. The results are compared with measured data.

  5. A microscopic derivation of nuclear collective rotation-vibration model and its application to nuclei

    NASA Astrophysics Data System (ADS)

    Gulshani, P.

    2016-07-01

    We derive a microscopic version of the successful phenomenological hydrodynamic model of Bohr-Davydov-Faessler-Greiner for collective rotation-vibration motion of an axially symmetric deformed nucleus. The derivation is not limited to small oscillation amplitude. The nuclear Schrodinger equation is canonically transformed to collective co-ordinates, which is then linearized using a constrained variational method. The associated constraints are imposed on the wavefunction rather than on the particle co-ordinates. The approach yields three self-consistent, time-reversal invariant, cranking-type Schrodinger equations for the rotation-vibration and intrinsic motions, and a self-consistency equation. For harmonic oscillator mean-field potentials, these equations are solved in closed forms for excitation energy, cut-off angular momentum, and other nuclear properties for the ground-state rotational band in some deformed nuclei. The results are compared with measured data.

  6. A primer on rotational collective enhancements in even-even nuclei

    SciTech Connect

    Younes, W

    2004-07-15

    The enhancement of the level density for deformed nuclei relative to the level density in spherical nuclei is calculated. The qualitative behavior of the enhancement factor as a function of excitation energy is explained, and a prescription for a more quantitative description of this behavior is suggested. The results presented here can be found elsewhere in the literature, however the treatments of this topic are dispersed in the literature, are often terse, and require some familiarity with disparate branches of physics. The emphasis of this paper is on step-by-step derivations of the physics and mathematics used in the calculation of level densities and rotational enhancement factors. Pertinent techniques from thermodynamics and group theory are introduced. Appendices provide detailed introductions to the principal mathematical tools.

  7. a Uqp(u2) Rotor Model for Rotational Bands of Superdeformed Nuclei

    NASA Astrophysics Data System (ADS)

    Barbier, R.; Meyer, J.; Kibler, M.

    A nonrigid rotor model is developed from the two-parameter quantum algebra Uqp(u2). (This model presents the Uqp(u2) symmetry and shall be refered to as the qp-rotor model.) A rotational energy formula as well as a qp-deformation of E2 reduced transition probabilities are derived. The qp-rotor model is applied (through fitting procedures) to twenty rotational bands of superdeformed nuclei in the A~130, 150, and 190 mass regions. Systematic comparisons between the qp-rotor model and the q-rotor model of Raychev, Roussev, and Smirnov, on one hand, and a basic three-parameter model, on the other, are performed on energy spectra, on dynamical moments of inertia and on B(E2) values. The physical significance of the deformation parameters q and p is discussed.

  8. Rotating Gravity Gradiometer Study

    NASA Technical Reports Server (NTRS)

    Forward, R. L.

    1976-01-01

    The application of a Rotating Gravity Gradiometer (RGG) system on board a Lunar Polar Orbiter (LPO) for the measurement of the Lunar gravity field was investigated. A data collection simulation study shows that a gradiometer will give significantly better gravity data than a doppler tracking system for the altitudes under consideration for the LOP, that the present demonstrated sensitivity of the RGG is adequate for measurement of the Lunar gravity gradient field, and that a single RGG instrument will provide almost as much data for geophysical interpretation as an orthogonal three axis RGG system. An engineering study of the RGG sensor/LPO spacecraft interface characteristics shows that the RGG systems under consideration are compatible with the present models of the LPO spacecraft.

  9. Theoretical study of the nuclear spin-molecular rotation coupling for relativistic electrons and non-relativistic nuclei. II. Quantitative results in HX (X = H,F,Cl,Br,I) compounds.

    PubMed

    Aucar, I Agustín; Gómez, Sergio S; Melo, Juan I; Giribet, Claudia C; Ruiz de Azúa, Martín C

    2013-04-07

    In the present work, numerical results of the nuclear spin-rotation (SR) tensor in the series of compounds HX (X = H,F,Cl,Br,I) within relativistic 4-component expressions obtained by Aucar et al. [J. Chem. Phys. 136, 204119 (2012)] are presented. The SR tensors of both the H and X nuclei are discussed. Calculations were carried out within the relativistic Linear Response formalism at the Random Phase Approximation with the DIRAC program. For the halogen nucleus X, correlation effects on the non-relativistic values are shown to be of similar magnitude and opposite sign to relativistic effects. For the light H nucleus, by means of the linear response within the elimination of the small component approach it is shown that the whole relativistic effect is given by the spin-orbit operator combined with the Fermi contact operator. Comparison of "best estimate" calculated values with experimental results yield differences smaller than 2%-3% in all cases. The validity of "Flygare's relation" linking the SR tensor and the NMR nuclear magnetic shielding tensor in the present series of compounds is analyzed.

  10. Projected shell model study of yrast states of neutron-deficient odd-mass Pr nuclei

    SciTech Connect

    Ibanez-Sandoval, A.; Ortiz, M. E.; Velazquez, V.; Galindo-Uribarri, A.; Hess, P. O.; Sun, Y.

    2011-03-15

    A wide variety of modern instruments allow us to study neutron-deficient nuclei in the A=130 mass region. Highly deformed nuclei have been found in this region, providing opportunities to study the deformed rotational bands. The description of the {sup 125,127,129,131,133}Pr isotopes with the projected shell model is presented in this paper. Good agreement between theory and experiment is obtained and some characteristics are discussed, including the dynamic moment of inertia J{sup (2)}, kinetic moment of inertia J{sup (1)}, the crossing of rotational bands, and backbending effects.

  11. Projected Shell Model Study of Yrast States of Neutron-Deficient Odd-Mass Pr Nuclei

    SciTech Connect

    Ibanes, A.; Ortiz, Mark E; Velazquez, V.; Galindo-Uribarri, Alfredo {nmn}; Hess, P. O.; Sun, Y.

    2011-01-01

    A wide variety of modern instruments allow us to study neutron-deficient nuclei in the A = 130 mass region. Highly deformed nuclei have been found in this region, providing opportunities to study the deformed rotational bands. The description of the 125,127,129,131,133Pr isotopes with the projected shell model is presented in this paper. Good agreement between theory and experiment is obtained and some characteristics are discussed, including the dynamic moment of inertia J (2), kinetic moment of inertia J (1), the crossing of rotational bands, and backbending effects.

  12. An empirical relation for rotational energies in neutron rich transitional nuclei around Aap100

    NASA Astrophysics Data System (ADS)

    Varshney, Mani; Bihari, Chhail; Singh, Y.; Singh, M.; Varshney, A. K.; Gupta, K. K.; Gupta, D. K.

    2007-04-01

    There exists a relation in asymmetric, inertial and variable of moment of inertia parameters that describes rotational band energies. The present study indicates the splitting of the so-called γ-band into two separate rotational energy branches of odd spin (3+, 5+, 7+...) and even spin (2+, 4+, 6+, 8+...).

  13. Dynamical Model for the Decay of Hot and Rotating Compound Nuclei

    SciTech Connect

    Gupta, Raj K.; Singh, Dalip; Arun, Sham K.; Niyti; Kumar, Raj

    2009-03-04

    As an alternative to the well known Hauser-Feshbach analysis and statistical fission model, a dynamical collective clusterization model, called the dynamical cluster-decay model (DCM), is developed for the decay of hot and rotating compound nuclei (CN) formed in the low-energy heavy ion reactions. The model is a non-statistical description for the decay of a CN to light particles (LPs), intermediate mass fragments (IMFs), fusion-fission (FF) and quasi-fission (QF)(equivalently, capture) processes. The model considers all decay products as dynamical mass motions of preformed fragments or clusters through the interaction barrier, thereby including structure effects of the CN, and is applicable to CN from different mass regions.

  14. Theoretical studies of hadrons and nuclei

    SciTech Connect

    COTANCH, STEPHEN R

    2007-03-20

    This report details final research results obtained during the 9 year period from June 1, 1997 through July 15, 2006. The research project, entitled Theoretical Studies of Hadrons and Nuclei , was supported by grant DE-FG02-97ER41048 between North Carolina State University [NCSU] and the U. S. Department of Energy [DOE]. In compliance with grant requirements the Principal Investigator [PI], Professor Stephen R. Cotanch, conducted a theoretical research program investigating hadrons and nuclei and devoted to this program 50% of his time during the academic year and 100% of his time in the summer. Highlights of new, significant research results are briefly summarized in the following three sections corresponding to the respective sub-programs of this project (hadron structure, probing hadrons and hadron systems electromagnetically, and many-body studies). Recent progress is also discussed in a recent renewal/supplemental grant proposal submitted to DOE. Finally, full detailed descriptions of completed work can be found in the publications listed at the end of this report.

  15. SU(3) gauge symmetry for collective rotational states in deformed nuclei

    NASA Astrophysics Data System (ADS)

    Rosensteel, George; Sparks, Nick

    2016-09-01

    How do deformed nuclei rotate? The qualitative answer is that a velocity-dependent interaction causes a strong coupling between the angular momentum and the vortex momentum (or Kelvin circulation). To achieve a quantitative explanation, we propose a significant extension of the Bohr-Mottelson legacy model in which collective wave functions are vector-valued in an irreducible representation of SU(3). This SU(3) is not the usual Elliott choice, but rather describes internal vorticity in the rotating frame. The circulation values C of an SU(3) irreducible representation, say the (8,0) for 20Ne, are C = 0, 2, 4, 6, 8, which is the same as the angular momentum spectrum in the Elliott model; the reason is a reciprocity theorem in the symplectic model. The differential geometry of Yang-Mills theory provides a natural mathematical framework to solve the angular-vortex coupling riddle. The requisite strong coupling is a ``magnetic-like'' interaction arising from the covariant derivative and the bundle connection. The model builds on prior work about the Yang-Mills SO(3) gauge group model.

  16. Rotational-vibrational Description of Nucleon Scattering on Actinide Nuclei Using a Dispersive Coupled-channel Optical Model

    NASA Astrophysics Data System (ADS)

    Quesada, J. M.; Capote, R.; Soukhovitskiı˜, E. Sh.; Chiba, S.

    2014-04-01

    Tamura's coupling formalism has been extended to consider low-lying rotational bands built on vibrational (single-particle) band heads in well-deformed even-even (odd) actinides. These additional excitations are introduced as a perturbation to the underlying rigid rotor structure that is known to describe well the ground state rotational band of major actinides. Coupling matrix elements needed in extended Tamura's formalism are derived for both even-even and odd actinides. Employed dispersive optical model (DCCOMP) replaces the incident proton energy Ep (for proton induced reactions) by the equivalent Coulomb subtracted energy in all potential terms including both the imaginary and real potentials with the corresponding dispersive corrections. Therefore, the optical potential becomes fully symmetric for protons and neutrons. This potential is used to fit simultaneously all the available optical experimental databases (including neutron strength functions) for nucleon scattering on 238U and 232Th (even even) nuclei. Quasi-elastic (p,n) scattering data to the isobaric analogue states of the target nuclei are also used to constrain the isovector part of the optical potential. Derived Lane-consistent DCCOMP is based on coupling of almost all levels below 1 MeV of excitation energy. The ground state, octupole, beta, gamma and non-axial rotational bands are considered for even nuclei, and rotational bands built on single-particle levels - for odd nuclei. Application of derived potential to odd targets based on a new coupling scheme is foreseen.

  17. Long-term Rotation State Evolution of Comet Nuclei Including the Effects of Jet Torques and Internal Dissipation

    NASA Astrophysics Data System (ADS)

    Jacobson, Seth A.; Scheeres, D. J.

    2012-05-01

    Many comet nuclei have been identified or are suspected to occupy non-principal axis (complex) rotation [Belton 2005, etc.] as well as have evolving rotation rates [Belton 2011, etc.]. Active areas of the surface and jets torque the nucleus during perihelion passage, while time variable internal stresses dissipate energy in the anelastic comet interior. These competing processes determine the comet’s nuclear rotation state. We developed a model for the evolution of the nuclei due to the reactive torques of a number of discrete jets located on the surface based on Neishtadt et al. [2002]. These jets are active only within a specific distance of the sun according to an empirical law determined by Marsden et al. (1973), however internal dissipation occurs as long as the body is not rotating about a principal axis. This internal dissipation is modeled according to Sharma et al. [2005] and Vokrouhlicky et al. [2009]. We average the full evolutionary equations over the rapidly changing spin angle, precession angle and true anomaly of the orbit. The averaged equations can rapidly calculate the long-term evolution of the nutation angle, cone angle and magnitude of the angular momentum vector over many perihelion passages. The averaged dynamical system is characterized by just two parameters: the first encapsulating the jet geometry and the second the coefficient of energy dissipation. Neishtadt et al. [2002] determined that there exist non-principal axis rotation fixed points, some even stable, for certain jet geometries. With the addition of internal dissipation, some of these fixed points disappear, while others remain but may change locations and classification as a function of the strength of energy dissipation at constant jet geometry. We explore this model of comet nuclei evolution to determine the rotation state of comet nuclei with changing jet geometries and constant coefficients of energy dissipation.

  18. Rotating gravity gradiometer study

    NASA Technical Reports Server (NTRS)

    Forward, R. L.

    1982-01-01

    Two rotating gravity gradiometer (RGG) sensors, along with all the external electronics needed to operate them, and the fixtures and special test equipment needed to fill and align the bearings, were assembled in a laboratory, and inspected. The thermal noise threshold of the RGG can be lowered by replacing a damping resistor in the first stage electronics by an active artificial resistor that generates less random voltage noise per unit bandwidth than the Johnson noise from the resistor it replaces. The artificial resistor circuit consists of an operational amplifier, three resistors, and a small DC to DC floating power supply. These are small enough to be retrofitted to the present circuit boards inside the RGG rotor in place of the 3 Megohm resistor. Using the artificial resistor, the thermal noise of the RGG-2 sensor can be lowered from 0.3 Eotvos to 0.15 Eotvos for a 10 sec integration time.

  19. Toroidal rotation studies in KSTAR

    NASA Astrophysics Data System (ADS)

    Lee, S. G.; Lee, H. H.; Yoo, J. W.; Kim, Y. S.; Ko, W. H.; Terzolo, L.; Bitter, M.; Hill, K.; KSTAR Team

    2014-10-01

    Investigation of the toroidal rotation is one of the most important topics for the magnetically confined fusion plasma researches since it is essential for the stabilization of resistive wall modes and its shear plays an important role to improve plasma confinement by suppressing turbulent transport. The most advantage of KSTAR tokamak for toroidal rotation studies is that it equips two main diagnostics including the high-resolution X-ray imaging crystal spectrometer (XICS) and charge exchange spectroscopy (CES). Simultaneous core toroidal rotation and ion temperature measurements of different impurity species from the XICS and CES have shown in reasonable agreement with various plasma discharges in KSTAR. It has been observed that the toroidal rotation in KSTAR is faster than that of other tokamak devices with similar machine size and momentum input. This may due to an intrinsically low toroidal field ripple and error field of the KSTAR device. A strong braking of the toroidal rotation by the n = 1 non-resonant magnetic perturbations (NRMPs) also indicates these low toroidal field ripple and error field. Recently, it has been found that n = 2 NRMPs can also damp the toroidal rotation in KSTAR. The detail toroidal rotation studies will be presented. Work supported by the Korea Ministry of Science, ICT and Future Planning under the KSTAR project.

  20. Electromagnetic Studies of Mesons, Nucleons, and Nuclei

    SciTech Connect

    Baker, Oliver K.

    2013-08-20

    Professor Baker was a faculty member at Hampton University in Hampton, Virginia, and, jointly, a Staff Physicist at Jefferson Lab in nearby Newport News from September 1989 to July 2006. The Department of Energy (DOE) funded the grant DE-FG02-97ER41035 Electromagnetic Studies of Mesons, Nucleons, and Nuclei, while Baker was in this joint appointment. Baker sent a closeout report on these activities to Hampton University’s Sponsored Research Office some years ago, shortly after joining Yale University in 2006. In the period around 2001, the research grant with Baker as the Principal Investigator (PI) was put under the supervision of Professor Liguang Tang at Hampton University. Baker continued to pursue the research while in this join appointment, however the administrative responsibilities with the DOE and with Hampton University rested with Professor Tang after 2001, to my recollection. What is written in this document is from Baker’s memory of the research activities, which he has not pursued since joining the Yale University faculty.

  1. Double rotation NMR studies of zeolites and aluminophosphate molecular sieves

    SciTech Connect

    Jelinek, Raz

    1993-07-01

    Goal is to study the organization and structures of guest atoms and molecules and their reactions on internal surfaces within pores of zeolites and aluminophosphate molecular sieves. 27Al and 23Na double rotation NMR (DOR) is used since it removes the anisotropic broadening in NMR spectra of quadrupolar nuclei, thus increasing resolution. This work concentrates on probing aluminum framework atoms in aluminophosphate molecular sieves and sodium extra framework cations in porous aluminosilicates. In aluminophosphates, ordering and electronic environments of the framework 27Al nuclei are modified upon adsorption of water molecules within the channels; a relation is sought between the sieve channel topology and the organization of adsorbed water, as well as the interaction between the Al nuclei and the water molecules. Extra framework Na+ cations are directly involved in adsorption processes and reactions in zeolite cavities.

  2. A microscopic study on shape transition and shape coexistence in superdeformed nuclei

    SciTech Connect

    Kanthimathi, G.; Boomadevi, N.; Rajasekaran, T. R.

    2012-08-15

    Superdeformed nuclei at high-spin states in several mass regions are investigated within a microscopic approach using cranked Nilsson-Strutinsky formalism to explore the equilibrium deformations in the ground state and their evolution with spin. Shape transition from normal deformed to superdeformed states with increasing spin is studied and a clear picture of shape coexistence is provided. Detailed information on spin, rotational energy, dynamical moment of inertia, and rotational frequency of superdeformed rotational bands is presented and the general features of superdeformed bands in certain mass regions are outlined. Rotational energy and dynamical moment of inertia are compared with available experimental data and the impact of temperature and pairing on superdeformed configuration are discussed.

  3. Scissors mode of Gd nuclei studied from resonance neutron capture

    SciTech Connect

    Kroll, J.; Baramsai, B.; Becker, J. A.; and others

    2012-10-20

    Spectra of {gamma} rays following the neutron capture at isolated resonances of stable Gd nuclei were measured. The objectives were to get new information on photon strength of {sup 153,155-159}Gd with emphasis on the role of the M1 scissors-mode vibration. An analysis of the data obtained clearly indicates that the scissors mode is coupled not only to the ground state, but also to all excited levels of the nuclei studied. The specificity of our approach ensures unbiasedness in estimating the sumed scissors-mode strength {Sigma}B(M1){up_arrow}, even for odd product nuclei, for which conventional nuclear resonance fluorescence measurements yield only limited information. Our analysis indicates that for these nuclei the sum {Sigma}B(M1){up_arrow} increases with A and for {sup 157,159}Gd it is significantly higher compared to {sup 156,158}Gd.

  4. Theoretical study of triaxial shapes of neutron-rich Mo and Ru nuclei

    DOE PAGES

    Zhang, C. L.; Bhat, G. H.; Nazarewicz, W.; ...

    2015-09-10

    Here, whether atomic nuclei can possess triaxial shapes at their ground states is still a subject of ongoing debate. According to theory, good prospects for low-spin triaxiality are in the neutron-rich Mo-Ru region. Recently, transition quadrupole moments in rotational bands of even-mass neutron-rich isotopes of molybdenum and ruthenium nuclei have been measured. The new data have provided a challenge for theoretical descriptions invoking stable triaxial deformations. The purpose of this study is to understand experimental data on rotational bands in the neutron-rich Mo-Ru region, we carried out theoretical analysis of moments of inertia, shapes, and transition quadrupole moments of neutron-richmore » even-even nuclei around 110Ru using self-consistent mean-field and shell model techniques. Methods: To describe yrast structures in Mo and Ru isotopes, we use nuclear density functional theory (DFT) with the optimized energy density functional UNEDF0. We also apply triaxial projected shell model (TPSM) to describe yrast and positive-parity, near-yrast band structures. As a result, our self-consistent DFT calculations predict triaxial ground-state deformations in 106,108Mo and 108,110,112Ru and reproduce the observed low-frequency behavior of moments of inertia. As the rotational frequency increases, a negative-gamma structure, associated with the aligned ν(h11/2)2 pair, becomes energetically favored. The computed transition quadrupole moments vary with angular momentum, which reflects deformation changes with rotation; those variations are consistent with experiment. The TPSM calculations explain the observed band structures assuming stable triaxial shapes. Lastly, the structure of neutron-rich even-even nuclei around Ru-110 is consistent with triaxial shape deformations. Our DFT and TPSM frameworks provide a consistent and complementary description of experimental data.« less

  5. Theoretical study of triaxial shapes of neutron-rich Mo and Ru nuclei

    SciTech Connect

    Zhang, C. L.; Bhat, G. H.; Nazarewicz, W.; Sheikh, J. A.; Shi, Yue

    2015-09-10

    Here, whether atomic nuclei can possess triaxial shapes at their ground states is still a subject of ongoing debate. According to theory, good prospects for low-spin triaxiality are in the neutron-rich Mo-Ru region. Recently, transition quadrupole moments in rotational bands of even-mass neutron-rich isotopes of molybdenum and ruthenium nuclei have been measured. The new data have provided a challenge for theoretical descriptions invoking stable triaxial deformations. The purpose of this study is to understand experimental data on rotational bands in the neutron-rich Mo-Ru region, we carried out theoretical analysis of moments of inertia, shapes, and transition quadrupole moments of neutron-rich even-even nuclei around 110Ru using self-consistent mean-field and shell model techniques. Methods: To describe yrast structures in Mo and Ru isotopes, we use nuclear density functional theory (DFT) with the optimized energy density functional UNEDF0. We also apply triaxial projected shell model (TPSM) to describe yrast and positive-parity, near-yrast band structures. As a result, our self-consistent DFT calculations predict triaxial ground-state deformations in 106,108Mo and 108,110,112Ru and reproduce the observed low-frequency behavior of moments of inertia. As the rotational frequency increases, a negative-gamma structure, associated with the aligned ν(h11/2)2 pair, becomes energetically favored. The computed transition quadrupole moments vary with angular momentum, which reflects deformation changes with rotation; those variations are consistent with experiment. The TPSM calculations explain the observed band structures assuming stable triaxial shapes. Lastly, the structure of neutron-rich even-even nuclei around Ru-110 is consistent with triaxial shape deformations. Our DFT and TPSM frameworks provide a consistent and complementary description of experimental data.

  6. Rotational Study of Natural Amino Acid Glutamine

    NASA Astrophysics Data System (ADS)

    Varela, Marcelino; Cabezas, Carlos; Alonso, José L.

    2014-06-01

    Recent improvements in laser ablation molecular beam Fourier transform microwave spectroscopy (LA-MB-FTMW) have allowed the investigation of glutamine (COOH-CH(NH2)-CH2-CH2-CONH2), a natural amino acid with a long polar side chain. One dominant structure has been detected in the rotational spectrum. The nuclear quadrupole hyperfine structure of two 14N nuclei has been totally resolved allowing the conclusive identification of the observed species.

  7. Effects of rotation of fissioning nuclei in the angular distributions of prompt neutrons and gamma rays originating from the polarized-neutron-induced fission of 233U and 235U nuclei

    NASA Astrophysics Data System (ADS)

    Danilyan, G. V.; Klenke, J.; Kopach, Yu. N.; Krakhotin, V. A.; Novitsky, V. V.; Pavlov, V. S.; Shatalov, P. B.

    2014-06-01

    The results of an experiment devoted to searches for effects of rotation of fissioning nuclei in the angular distributions of prompt neutrons and gamma rays originating from the polarized-neutron-induced fission of 233U nuclei are presented. The effects discovered in these angular distributions are opposite in sign to their counterparts in the polarized-neutron-induced fission of 235U nuclei. This is at odds with data on the relative signs of respective effects in the angular distribution of alpha particles from the ternary fission of the same nuclei and may be indicative of problems in the model currently used to describe the effect in question. The report on which this article is based was presented at the seminar held at the Institute of Theoretical and Experimental Physics and dedicated to the 90th anniversary of the birth of Yu.G. Abov, corresponding member of Russian Academy of Sciences, Editor in Chief of the journal Physics of Atomic Nuclei.

  8. Possible conservation of the K-quantum number in excited rotating nuclei

    SciTech Connect

    Bracco, A.; Bosetti, P.; Leoni, S. |

    1996-12-31

    The {gamma}-cascades feeding into low-K and high-K bands in the nucleus {sup 163}Er are investigated by analyzing variances and covariances of the spectrum fluctuations. The study of the covariance between pairs of gated spectra reveals that the cascades feeding into the low-K bands are completely different from those feeding the high-K bands. In addition, the number of decay paths obtained analyzing the ridge and the valley in spectra gated by high-K transitions is different than that deduced from the total spectrum. This result is well reproduced with microscopic calculations of strongly interacting bands. It is concluded that the K-selection rules are effective for the excited rotational bands within the angular momentum region probed by the experiment, 30{Dirac_h} {le} I {le} 40{Dirac_h}.

  9. [Neuropeptides in the raphe nuclei: an immunocytochemical study].

    PubMed

    Coveñas, R; Marcos, P; Belda, M; de León, M; Narváez, J A; Aguirre, J A; González-Barón, S

    The raphe nuclei are involved in numerous mechanisms, included the antinociceptives. In the raphe nuclei of the cat, the distribution of neuropeptides is not very studied. Aim. To know the distribution of peptidergic fibers and cell bodies in the raphe nuclei of the cat. We studied a total of fifteen neuropeptides. We used four control cats (without colchicine) and six with colchicine (administered into the Sylvian aqueduct). We used an indirect immunocytochemical technique. The histologic controls carried out confirm the specificity of the primary and secondary antibodies used. We observed in the fibers and/or the cell bodies located in the dorsal raphe nucleus a total of 14 neuropeptides, 12 in the raphe pallidus, 11 in the medial raphe, 10 in the raphe magnus, 8 in the raphe pontis and 7 in the raphe obscurus. We observed immunoreactive cell bodies in the raphe pallidus (with neurokinin A/leucine enkephalin), in the medial raphe (beta endorphin/alpha neo endorphin), in the raphe magnus (leucine enkephalin) and in the dorsal raphe (beta endorphin/alpha neo endorphin/methionine enkephalin Arg6 Gly7 Leu8/leucine enkephalin/neurokinin A/neurotensin). 1. There are differences on the distribution of the peptidergic fibers/cell bodies observed in the raphe nuclei of the rat, the cat and the man; 2. The raphe nuclei could receive peptidergic afferences containing dynorphin A, galanin, neuropeptide Y, somatostatin ; 3. The cell bodies located in the medial raphe and containing beta endorphin or alpha neo endorphin could be projecting neurons; 4. There is a great functional complexity in the raphe nuclei due to the great number of neuropeptides observed in them; 5. The neuropeptides could interact between them, and 6. The neuropeptides located in the raphe nuclei could be involved in the control of the nociceptive information.

  10. The emergence of deformation and rotational states in the many-nucleon quantum theory of nuclei

    NASA Astrophysics Data System (ADS)

    Rowe, D. J.

    2016-02-01

    The many-nucleon quantum mechanics of a nucleus is infinite-dimensional and, although simply defined, it has the potential for unlimited complexity. Nevertheless, the low-energy states of heavy open-shell nuclei exhibit properties that are remarkably well described by simple collective models. This paper examines this emergent simplicity from a perspective that closely parallels the emergence of shell structure in the Mayer-Jensen model. The result is an expression of the many-nucleon Hilbert space of a nucleus as an energy-ordered sum of subspaces each of which carries a microscopic version of the Bohr-Mottelson unified model. Each of the subspaces is characterized by nuclear states with a common intrinsic shape defined by its quadrupole moments. An emergence of simplicity and shape-coexistence in nuclei is then explained if it can be demonstrated that there is a relatively small and coherent mixing of the states of different collective subspaces.

  11. Recent studies of heavy nuclei far from stability at JYFL

    SciTech Connect

    Julin, R.; Enqvist, T.; Helariutta, K.

    1996-12-31

    The new K=130 Cyclotron + ECR facility of the Physics Department of the University of Jyvaskyla (JYFL) provides stable beams from protons up to krypton ions for nuclear structure studies. Two instruments designed especially for in-beam spectroscopic studies of heavy nuclei at JYFL are introduced in this contribution. Some results from recent measurements with them are reported.

  12. Shape-coexisting rotation in neutron-deficient Hg and Pb nuclei

    NASA Astrophysics Data System (ADS)

    Jiao, C. F.; Shi, Yue; Liu, H. L.; Xu, F. R.; Walker, P. M.

    2015-03-01

    For a shape-soft nucleus, the deformation change with increasing angular momentum of rotation can be significant. Total-Routhian-surface (TRS) calculations include the shape changes, but angular momentum is not conserved (neither is it a good quantum number, nor is it kept unchanged in the whole TRS mesh). In the projected shell model (PSM), the angular momentum appears as a good quantum number, but calculations have usually been performed with fixed deformation. In the present work, by performing angular-momentum projection on the mean-field potential-energy surface (PES), we can obtain an angular-momentum-conserved PES which gives deformation for a rotational state at a given spin. In order to investigate the shape-changing effect, we have chosen neutron-deficient Hg and Pb isotopes in which shape coexistence occurs. We interpret the irregular rotational behavior of the oblate bands at low spin as arising from deformation changes which are induced by collective rotation. At higher spin, the oblate rotational spectrum can also be influenced by the crossing between the K =0 ground-state band and a low-K two-quasineutron band. Calculated g factors for the states of oblate bands are given for future experimental testing, and the intrinsic structures of high-K oblate states are investigated.

  13. Studies of Heavy-Ion Reactions and Transuranic Nuclei

    SciTech Connect

    Schroeder, W. Udo

    2016-07-28

    Studies of heavy-ion reactions and transuranic nuclei performed by the University of Rochester Nuclear Science Research Group have been successful in furthering experimental systematics and theoretical understanding of the behavior of nuclear systems excited to their limits of stability. The theoretical results explain specifically the “boiling” and “vaporization” of atomic nuclei, but are more generally applicable to isolated, quantal many-particle systems which, under thermal or mechanical stresses, all disintegrate by evaporation, via surface cluster emission, or via fission-like processes. Accompanying experimental investigations by the group have demonstrated several new types of dynamical instability of nuclei: In central, “head-on” collisions, target nuclei exhibit limited ability to stop energetic projectile nuclei and to dissipate the imparted linear momentum. Substantial matter overlap (“neck”) between projectile and target nuclei, which is observed at elevated collision energies, can be stretched considerably and break at several places simultaneously. These results provide new testing grounds for microscopic theory of the cohesion of nuclear matter. This property has remained elusive, even though the elementary nucleon-nucleon forces are well known since some time. Technical R&D has resulted in a detailed characterization of a novel plastic material, which can now be used in the design of sensitive diagnostic systems for various types of radio-activity. Innovative application of powerful laser systems has produced intense, controllable sources of exotic particle radioactivity for nuclear investigations. Several students have received their Ph.D. degree in experimental nuclear science for their work on basic nuclear research or R&D projects.

  14. 58Ni: an unpaired band crossing at new heights of angular momentum for rotating nuclei.

    PubMed

    Rudolph, D; Carlsson, B G; Ragnarsson, I; Aberg, S; Andreoiu, C; Bentley, M A; Carpenter, M P; Charity, R J; Clark, R M; Cromaz, M; Ekman, J; Fahlander, C; Fallon, P; Ideguchi, E; Macchiavelli, A O; Mineva, M N; Reviol, W; Sarantites, D G; Seweryniak, D; Williams, S J

    2006-03-10

    High-spin states in 58Ni have been investigated by means of the fusion-evaporation reaction 28Si(32S, 2p)58Ni at 130 MeV beam energy. Discrete-energy levels are observed in 58Ni at record-breaking 42 MeV excitation energy and angular momenta in excess of 30h. The states form regular rotational bands with unprecedented high rotational frequencies. A comparison with configuration dependent cranked Nilsson-Strutinsky calculations reveals an exceptional two-band crossing scenario, the interaction strength of which is strongly shape dependent.

  15. A number-projected model with generalized pairing interaction in application to rotating nuclei

    SciTech Connect

    Satula, W. |||; Wyss, R.

    1996-12-31

    A cranked mean-field model that takes into account both T=1 and T=0 pairing interactions is presented. The like-particle pairing interaction is described by means of a standard seniority force. The neutron-proton channel includes simultaneously correlations among particles moving in time reversed orbits (T=1) and identical orbits (T=0). The coupling between different pairing channels and nuclear rotation is taken into account selfconsistently. Approximate number-projection is included by means of the Lipkin-Nogami method. The transitions between different pairing phases are discussed as a function of neutron/proton excess, T{sub z}, and rotational frequency, {Dirac_h}{omega}.

  16. Deformed rotational bands in the doubly odd nuclei [sup 134]Pr and [sup 132]Pr

    SciTech Connect

    Hauschild, K.; Wadsworth, R.; Clark, R.M.; Hibbert, I.M. ); Beausang, C.W.; Forbes, S.A.; Nolan, P.J.; Paul, E.S.; Semple, A.T.; Wilson, J.N. ); Gizon, A.; Gizon, J.; Santos, D. ); Simpson, J. )

    1994-08-01

    The nuclei [sup 132,134]Pr have been investigated using the [sup 100]Mo([sup 37]Cl,[ital xn]) reactions at a beam energy of 155 MeV. Gamma rays were detected with the Eurogam array. Analysis of the data has revealed the presence of two new weakly populated decoupled bands in [sup 134]Pr. One of these bands has been linked into the normal-deformed states and is thought to be built on a [pi]([ital h][sub 11/2])[sup 2][direct product][nu]([ital f][sub 7/2],[ital h][sub 9/2]) configuration. The second band has been interpreted as being based on a [pi]([ital h][sub 11/2])[sup 3][direct product][nu][ital i][sub 13/2] intruder configuration within the second [beta][sub 2][congruent]0.3 prolate minimum. The known decoupled band in [sup 132]Pr (5[ital n] reaction channel) and the highly deformed band in [sup 130]La A([alpha]3[ital n]) have also been extended. The structure of all of these bands is discussed together with similar bands in nieghboring odd-odd nuclei.

  17. Rotational properties of N {approx} Z nuclei in the presence of neutron-proton correlations

    SciTech Connect

    Sitdikov, A. S. Nikitin, A. S.; Khamzin, A. A.

    2008-02-15

    In the Hartree-Fock-Bogolyubov approximation, the cranking model is formulated with allowance for residual neutron-proton correlations whose interaction has a Gaussian form. The behavior of quasiparticle levels versus the frequency of rotation of the even-even isotopes {sup 72-76}Kr is investigated within this approach.

  18. Theoretical studies on the modes of decay of superheavy nuclei

    NASA Astrophysics Data System (ADS)

    Santhosh, K. P.; Nithya, C.

    2016-11-01

    The decay modes of recently synthesized superheavy nuclei are investigated by comparing the α -decay half-lives with the spontaneous fission half-lives. α -decay half-lives are calculated using the Coulomb and proximity potential model for deformed nuclei (CPPMDN). The agreement between theoretical and experimental α half-lives shows the predictability of the CPPMDN in the superheavy region. A modified formula is proposed for calculating the spontaneous fission half-lives including the shell correction. The agreement between theoretical predictions and experimental results of spontaneous fission half-lives is satisfactory for heavy and superheavy nuclei ranging from Th to Fl. A comparison between the spontaneous fission half-lives computed using eight different formalisms is performed for even-even superheavy nuclei in the range of 108 ≤Z ≤120 . Even though all these models can reproduce the experimental spontaneous fission half-lives, model-to-model variations in predicting the fission half-lives in superheavy region is evident from the study.

  19. Decay studies of heavy and superheavy nuclei

    NASA Astrophysics Data System (ADS)

    Clark, Roderick M.

    2016-12-01

    In this contribution I discuss recent results on the decay of excited states, via electromagnetic transitions (γ-ray and conversion electrons), α decay, and fission, and discuss what these studies reveal in terms of the stability of the heaviest elements.

  20. Gas and dust emission from comets and life spans of active areas on their rotating nuclei

    NASA Technical Reports Server (NTRS)

    Sekanina, Z.

    1990-01-01

    Outgassing and dust emission from discrete regions on the nuclei of comets are investigated with regard to the processes of activation, dormancy, reactivation, and extinction. With regard to P/Halley, P/Encke, P/Tempel 2, P/Machholz, P/Takamizawa, Bowell and some other new comets, the evolution of one active region of the nucleus surface appears to be independent of the evolution of another active region. The traditional concept of deactivation as a slow and monolithic process needs to be replaced with a more dynamic concept of intermittent periods of dormancy and reactivation of individual vents, varying in size. Life spans of discrete sources of activity are estimated to be at a few hundred revolutions about the sun for comets with perihelia at heliocentric distances of less than 2 AU, if the bulk density is very low.

  1. Laser ablated hydantoin: A high resolution rotational study.

    PubMed

    Alonso, Elena R; Kolesniková, Lucie; Alonso, José L

    2017-09-28

    Laser ablation techniques coupled with broadband and narrowband Fourier transform microwave spectroscopies have allowed the high resolution rotational study of solid hydantoin, an important target in astrochemistry as a possible precursor of glycine. The complicated hyperfine structure arising from the presence of two (14)N nuclei in non-equivalent positions has been resolved and interpreted in terms of the nuclear quadrupole coupling interactions. The results reported in this work provide a solid base for the interstellar searches of hydantoin in the astrophysical surveys. The values of the nuclear quadrupole coupling constants have been also discussed in terms of the electronic environment around the respective nitrogen atom.

  2. Delta I = 1 staggering effect for negative parity rotational bands with K = 1/2 in W/Os/Pt odd-mass nuclei

    NASA Astrophysics Data System (ADS)

    Taha, M. M.

    2015-11-01

    The anomalous negative-parity bands of odd-mass nuclei W/Os/Pt for N = 103 isotones are studied within the framework of particle rotor model (PRM). The phenomenon of Δ I = 1 staggering or signature splitting in energies occurs as one plots the gamma transitional energy over spin (EGOS) versus spin for the 1/2-[521] band originating from N = 5 single particle orbital. The rotational band with K = 1/2 separates into two signature partners. The levels with I = 1/2, 5/2, 9/2,… are displaced relatively to the levels with I = 3/2,7/2,11/2,…. The deviations of the level energies from the rigid rotor values is described by Coriolis coupling.

  3. Magnetic rotation (MR) band crossing in N=78 odd-Z nuclei: Tilted axis cranking (TAC) calculations to explore the role of nucleons

    SciTech Connect

    Kumar, Suresh

    2014-08-14

    Magnetic Rotation (MR) band crossing is studied systematically in N=78 isotones (La, Pr, Pm and Eu) using Tilted Axis Cranking (TAC) model. The observables such as I(¯h) vs ¯hω, excitation energy E(MeV) vs spin I(¯h), and the B(M1)/B(E2) vs I(¯h) were considered to pinpoint MR crossing in these nuclei. The results of tilted axis cranking were compared with these experimental observables. The B(M1) and B(E2) values were also reported and used to understand the crossing behaviour of these MR bands. The systematic evolution of this phenomenon in N=78 odd-Z istotones leads to understand the role of nucleons in MR band crossing.

  4. Quantum state tomography for quadrupolar nuclei using global rotations of the spin system.

    PubMed

    Teles, J; deAzevedo, E R; Auccaise, R; Sarthour, R S; Oliveira, I S; Bonagamba, T J

    2007-04-21

    In this paper, we describe a quantum state tomography method based on global rotations of the spin system which, together with a coherence selection scheme, enables the complete density matrix reconstruction. The main advantage of this technique, in respect to previous proposals, is the use of much shorter rf pulses, which decreases significantly the time necessary for algorithm quantum state tomography. In this case, under adequate experimental conditions, the rf pulses correspond to simple spatial rotations of the spin states, and its analytical description is conveniently given in the irreducible tensor formalism. Simulated results show the feasibility of the method for a single spin 72 nucleus. As an experimental result, we exemplify the application of this method by tomographing the steps during the implementation of the Deutsch algorithm. The algorithm was implemented in a (23)Na quadrupole nucleus using the strongly modulated pulses technique. We also extended the tomography method for a 3-coupled homonuclear spin 12 system, where an additional evolution under the internal Hamiltonian is necessary for zero order coherences evaluation.

  5. The Array for Nuclear Astrophysics Studies with Exotic Nuclei (anasen)

    NASA Astrophysics Data System (ADS)

    Matos, M.; Blackmon, J. C.; Gardiner, H. E.; Linhardt, L. E.; Macon, K. T.; Mondello, L. L.; Baby, L.; Johnson, E.; Koshchiy, E.; Rogachev, G.; Wiedenhöver, I.; Bardayan, D. W.

    2013-03-01

    Experimental information about most reactions involving short-lived nuclei is limited. New facilities aim to provide wider access to unstable isotopes, but the limited intensities require more efficient and selective techniques and devices. The Array for Nuclear Astrophysics Studies with Exotic Nuclei (ANASEN) is a charged-particle detector array designed primarily for studies of reactions important in the αp- and rp- processes with proton-rich exotic nuclei. The array consists of 40 silicon-strip detectors backed with CsI scintillators. The detectors cover an area of about 1300 cm2 providing essentially complete solid angle coverage for the reactions of interest with good energy and position resolution. ANASEN also includes a position-sensitive annular gas proportional counter that allows it to be used as an active gas target/detector. ANASEN is designed for direct measurement of (α,p) re-actions in inverse kinematics as well as for studies of proton elastic and inelastic scattering, (p, γ) reactions and transfer reactions. The array is being developed by Louisiana State University and Florida State University. Presently it is located at the RESOLUT radioacitve ion beam facility at FSU, where the first experiments are being performed. In the future, the array will be used at the ReA3 facility at the National Superconducting Cyclotron Laboratory.

  6. Threshold photoneutron angular distribution and polarization studies of nuclei

    SciTech Connect

    Holt, R.J.

    1980-01-01

    The photoneutron method was applied to the study of: (1) deuteron photodisintegration; (2) giant magnetic dipole resonances in heavy nuclei; (3) mechanism of radiative capture in light nuclei; and (4) isospin splitting of the giant dipole resonance in /sup 60/Ni. These studies were performed with the pulsed bremsstrahlung beam and high-resolution spectrometer available at the Argonne high-current electron linac. A threshold photoneutron polarization method was developed in order to search for the giant M1 resonance in heavy nuclei. A surprisingly small amount of M1 strength was found in /sup 208/Pb. Furthermore, the M1 strength for the 5.08-MeV excitation in /sup 17/O, the best example of a single-particle M1 resonance in nuclei, was found to be strongly quenched. In addition, the /sup 17/O(..gamma..,n/sub 0/)/sup 16/O reaction was found to provide an ideal example of the Lane-Lynn theory of radiative capture. The interplay among the three components of the theory, internal, channel and potential capture, were evident from the data. An electron beam transport system was developed which allows the bremsstrahlung to impinge on the photoneutron target on an axis perpendicular to the usual reaction plane. This system provides an accurate method for the measurement of relative angular distributions in (..gamma..,n) reactions. This system was applied to a high-accuracy measurement of the relative angular distribution for the D(..gamma..,n)H reaction. The question of isospin-splitting of the giant dipole resonance in /sup 60/Ni was studied by using the unique pico-pulse from the accelerator and the newly installed 25-m, neutron flight paths. The results provide clear evidence for the effect of isospin splitting.

  7. Neutron skin studies of medium and heavy nuclei

    NASA Astrophysics Data System (ADS)

    Thiel, M.; Becker, D.; Ferretti, M.; Kumar, K.; Sfienti, C.

    2014-06-01

    The recent PREX experiment at JLab has demonstrated the sensitivity of parity violating electron scattering to the neutron density, meanwhile outlining its major experimental challenges. On the other side, intermediate energy photons are an ideal probe for studying the properties of strongly interacting matter from the nuclear scale down to the sub-nuclear components of the nucleus. Among others coherent pion photoproduction can provide information on the existence and nature of neutron skins in nuclei. The simultaneous combination of different techniques allows a systematic determination across the periodic table thus benchmarking modern calculation. Recently a systematic investigation of the latter method has been exploited at MAMI (Mainz). At MESA the same setup as in the measurement of the weak mixing angle can be used to determine the parity-violating asymmetry for polarized electrons scattered on heavy nuclei with a 1% resolution. Status and prospects of the projects are presented.

  8. Rotational Spectroscopy of CF_2ClCCl_3 and Analysis of Hyperfine Structure from Four Quadrupolar Nuclei

    NASA Astrophysics Data System (ADS)

    Kisiel, Zbigniew; Bialkowska-Jaworska, Ewa; Uriarte, Iciar; Basterretxea, Francisco J.; Cocinero, Emilio J.

    2016-06-01

    CF_2ClCCl_3 has recently been identified among several new ozone- depleting substances in the atmosphere. There are no literature reports concerning rotational spectroscopy of this molecule, although we were recently able to report its first chirped pulse, supersonic expansion spectrum. CF_2ClCCl_3 has a rather small dipole moment so that the spectrum is weak and each transition displays very complex nuclear quadrupole hyperfine structure resulting from the presence of four chlorine nuclei. We have presently been able to carry out a complete analysis of the hyperfine structure by combining the information from chirped pulse spectra with dedicated higher resolution measurements made with a cavity supersonic expansion instrument. The hyperfine analysis was carried out with Pickett's SPFIT/SPCAT package and the sizes of Hamiltonian matrices are sufficiently large to require the use of 64-bit compilation of these programs (made available for both Windows and Linux systems on the PROSPE website). The resulting fit is to within experimental accuracy and is supported by ab initio calculations. The precise values of off-diagonal hyperfine constants for all nuclei lead to useful angular information that is complementary to direct structural information from moments of inertia. J.C.Laube, M.J.Newland, C.Hogan, et al., Nature Geoscience 7, 266 (2014). Z.Kisiel, E.Białkowska-Jaworska, L.Pszczółkowski, I.Uriarte, P.Ejica, F.J.Basterretxea, E.J.Cocinero, 70th ISMS, Champaign-Urbana, Illinois, RF-11 (2015). Z.Kisiel, E.Białkowska-Jaworska, L.Pszczółkowski, J.Chem.Phys. 109, 10263 (1998).

  9. Studies of 44Ti and 48Cr Nuclei Within Variational Mean Field Theory

    NASA Astrophysics Data System (ADS)

    Roy, Prianka; Dhiman, Shashi K.

    We have studied the nuclear structure properties of high angular momentum states in N = Z, 44Ti, and 48Cr nuclei by using Hartree-Fock-Bogoliubov (HFB) method with variation after angular momentum projection (VAP-HFB) technique. Effect of Kuo-Brown "KB" and its modified effective interactions has been studied using four sets of single-particle energies (SPEs) on rotational bands of these nuclei. It is seen that the HFB theory with projected wave functions by employing the VAP method describes well the overall trends of the experimental yrast level spectrum and the transition probabilities in these nuclei. The backbending of the 48Cr nucleus has been well reproduced by the present VAP-HFB calculations with the original "KB" effective interaction at J = 12ℏ. The modified effective interaction also gives backbending for 48Cr but at J = 10ℏ. The shape change associated with backbending effect in 48Cr is due to the large decrease in B(E2↓) values beyond J = 12ℏ state.

  10. Rotation and shape changes in Tb151 and Pb196: Probes of nuclear structure and tunneling process in warm nuclei. II. Microscopic Monte Carlo simulation

    NASA Astrophysics Data System (ADS)

    Leoni, S.; Benzoni, G.; Blasi, N.; Bracco, A.; Camera, F.; Corsi, A.; Crespi, F. C. L.; Mason, P.; Million, B.; Montanari, D.; Pignanelli, M.; Vigezzi, E.; Wieland, O.; Matsuo, M.; Shimizu, Y. R.; Curien, D.; Duchêne, G.; Robin, J.; Bednarczyk, P.; Castoldi, M.; Herskind, B.; Kmiecik, M.; Maj, A.; Meczynski, W.; Styczen, J.; Zieblinski, M.; Zuber, K.; Zucchiatti, A.

    2009-06-01

    A Monte Carlo simulation of the γ decay of superdeformed nuclei has been developed. It is based on microscopic calculations for the energy levels, E2 decay probabilities, collective mass parameters, and potential energy barriers. The use of microscopically calculated quantities largely reduces the parameters of the simulation, allowing one to focus on the basic ingredients of the physical processes. Calculations are performed for the warm rotating superdeformed nuclei Tb151 and Pb196, for which high statistics Euroball IV data are available. The dependence on the simulation parameters is investigated, together with the basic features of the microscopic calculations.

  11. Rotation and shape changes in {sup 151}Tb and {sup 196}Pb: Probes of nuclear structure and tunneling process in warm nuclei. II. Microscopic Monte Carlo simulation

    SciTech Connect

    Leoni, S.; Bracco, A.; Camera, F.; Corsi, A.; Crespi, F. C. L.; Montanari, D.; Pignanelli, M.; Benzoni, G.; Blasi, N.; Million, B.; Vigezzi, E.; Wieland, O.; Mason, P.; Matsuo, M.; Shimizu, Y. R.; Curien, D.; Duchene, G.; Robin, J.; Bednarczyk, P.; Kmiecik, M.

    2009-06-15

    A Monte Carlo simulation of the {gamma} decay of superdeformed nuclei has been developed. It is based on microscopic calculations for the energy levels, E2 decay probabilities, collective mass parameters, and potential energy barriers. The use of microscopically calculated quantities largely reduces the parameters of the simulation, allowing one to focus on the basic ingredients of the physical processes. Calculations are performed for the warm rotating superdeformed nuclei {sup 151}Tb and {sup 196}Pb, for which high statistics Euroball IV data are available. The dependence on the simulation parameters is investigated, together with the basic features of the microscopic calculations.

  12. Theoretical study of the relativistic molecular rotational g-tensor

    SciTech Connect

    Aucar, I. Agustín Gomez, Sergio S.; Giribet, Claudia G.; Ruiz de Azúa, Martín C.

    2014-11-21

    An original formulation of the relativistic molecular rotational g-tensor valid for heavy atom containing compounds is presented. In such formulation, the relevant terms of a molecular Hamiltonian for non-relativistic nuclei and relativistic electrons in the laboratory system are considered. Terms linear and bilinear in the nuclear rotation angular momentum and an external uniform magnetic field are considered within first and second order (relativistic) perturbation theory to obtain the rotational g-tensor. Relativistic effects are further analyzed by carrying out the linear response within the elimination of the small component expansion. Quantitative results for model systems HX (X=F, Cl, Br, I), XF (X=Cl, Br, I), and YH{sup +} (Y=Ne, Ar, Kr, Xe, Rn) are obtained both at the RPA and density functional theory levels of approximation. Relativistic effects are shown to be small for this molecular property. The relation between the rotational g-tensor and susceptibility tensor which is valid in the non-relativistic theory does not hold within the relativistic framework, and differences between both molecular parameters are analyzed for the model systems under study. It is found that the non-relativistic relation remains valid within 2% even for the heavy HI, IF, and XeH{sup +} systems. Only for the sixth-row Rn atom a significant deviation of this relation is found.

  13. Theoretical study of the relativistic molecular rotational g-tensor.

    PubMed

    Aucar, I Agustín; Gomez, Sergio S; Giribet, Claudia G; Ruiz de Azúa, Martín C

    2014-11-21

    An original formulation of the relativistic molecular rotational g-tensor valid for heavy atom containing compounds is presented. In such formulation, the relevant terms of a molecular Hamiltonian for non-relativistic nuclei and relativistic electrons in the laboratory system are considered. Terms linear and bilinear in the nuclear rotation angular momentum and an external uniform magnetic field are considered within first and second order (relativistic) perturbation theory to obtain the rotational g-tensor. Relativistic effects are further analyzed by carrying out the linear response within the elimination of the small component expansion. Quantitative results for model systems HX (X=F, Cl, Br, I), XF (X=Cl, Br, I), and YH(+) (Y=Ne, Ar, Kr, Xe, Rn) are obtained both at the RPA and density functional theory levels of approximation. Relativistic effects are shown to be small for this molecular property. The relation between the rotational g-tensor and susceptibility tensor which is valid in the non-relativistic theory does not hold within the relativistic framework, and differences between both molecular parameters are analyzed for the model systems under study. It is found that the non-relativistic relation remains valid within 2% even for the heavy HI, IF, and XeH(+) systems. Only for the sixth-row Rn atom a significant deviation of this relation is found.

  14. Giant dipole resonance built on hot rotating nuclei produced during evaporation of light particles from the 88Mo compound nucleus

    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.

  15. Systematic study of bubble nuclei in relativistic mean field model

    SciTech Connect

    Shukla, A.; Åberg, S.; Bajpeyi, A.

    2016-01-15

    We have theoretically studied potential bubble nuclei ({sup 20,22}O, {sup 34,36}Si, and {sup 46}Ar), which are experimentally accessible and have attracted several studies in the recent past. Relativistic mean field is employed in conjunction with the NL–SH parameter set. Our results show that among the possible candidates, {sup 22}Oand {sup 34}Si may be the most prominent candidates, showing significant depletion of density at the center, which could be verified experimentally in the near future with some of the experiments underway.

  16. Analytical and phenomenological studies of rotating turbulence

    NASA Technical Reports Server (NTRS)

    Mahalov, Alex; Zhou, YE

    1995-01-01

    A framework, which combines mathematical analysis, closure theory, and phenomenological treatment, is developed to study the spectral transfer process and reduction of dimensionality in turbulent flows that are subject to rotation. First, we outline a mathematical procedure that is particularly appropriate for problems with two disparate time scales. The approach which is based on the Green's method leads to the Poincare velocity variables and the Poincare transformation when applied to rotating turbulence. The effects of the rotation are now reflected in the modifications to the convolution of a nonlinear term. The Poincare transformed equations are used to obtain a time-dependent analog of the Taylor-Proudman theorem valid in the asymptotic limit when the non-dimensional parameter mu is identical to Omega(t) approaches infinity (Omega is the rotation rate and t is the time). The 'split' of the energy transfer in both direct and inverse directions is established. Secondly, we apply the Eddy-Damped-Quasinormal-Markovian (EDQNM) closure to the Poincare transformed Euler/Navier-Stokes equations. This closure leads to expressions for the spectral energy transfer. In particular, an unique triple velocity decorrelation time is derived with an explicit dependence on the rotation rate. This provides an important input for applying the phenomenological treatment of Zhou. In order to characterize the relative strength of rotation, another non-dimensional number, a spectral Rossby number, which is defined as the ratio of rotation and turbulence time scales, is introduced. Finally, the energy spectrum and the spectral eddy viscosity are deduced.

  17. Charged particle decay of hot and rotating 88Mo nuclei in fusion-evaporation reactions

    NASA Astrophysics Data System (ADS)

    Valdré, S.; Piantelli, S.; Casini, G.; Barlini, S.; Carboni, S.; Ciemała, M.; Kmiecik, M.; Maj, A.; Mazurek, K.; Cinausero, M.; Gramegna, F.; Kravchuk, V. L.; Morelli, L.; Marchi, T.; Baiocco, G.; Bardelli, L.; Bednarczyk, P.; Benzoni, G.; Bini, M.; Blasi, N.; Bracco, A.; Brambilla, S.; Bruno, M.; Camera, F.; Chbihi, A.; Corsi, A.; Crespi, F. C. L.; D'Agostino, M.; Degerlier, M.; Fabris, D.; Fornal, B.; Giaz, A.; Krzysiek, M.; Leoni, S.; Matejska-Minda, M.; Mazumdar, I.; MÈ©czyński, W.; Million, B.; Montanari, D.; Myalski, S.; Nicolini, R.; Olmi, A.; Pasquali, G.; Prete, G.; Roberts, O. J.; Styczeń, J.; Szpak, B.; Wasilewska, B.; Wieland, O.; Wieleczko, J. P.; ZiÈ©bliński, M.

    2016-03-01

    A study of fusion-evaporation and (partly) fusion-fission channels for the 88Mo compound nucleus, produced at different excitation energies in the reaction 48Ti+40Ca at 300, 450, and 600 MeV beam energies, is presented. Fusion-evaporation and fusion-fission cross sections have been extracted and compared with the existing systematics. Experimental data concerning light charged particles have been compared with the prediction of the statistical model in its implementation in the gemini++ code, well suited even for high spin systems, in order to tune the main model parameters in a mass region not abundantly covered by exclusive experimental data. Multiplicities for light charged particles emitted in fusion evaporation events are also presented. Some discrepancies with respect to the prediction of the statistical model have been found for forward emitted α particles; they may be due both to pre-equilibrium emission and to reaction channels (such as deep inelastic collisions or quasifission/quasifusion) different from the compound nucleus formation.

  18. Studies Of Proton Emitting Nuclei At Legnaro National Laboratories

    NASA Astrophysics Data System (ADS)

    Soramel, F.; Guglielmetti, A.; Bonetti, R.; Gernetti, M.; Stroe, L.; Mazzocco, M.; Signorini, C.; Ivasçu, M.; Petrache, C. M.

    2003-09-01

    Since few years at the Legnaro National Laboratories we have recently started a program to study exotic decays at the proton drip-line with particular attention to proton radioactivity in the rare earth region. In fact pemitting nuclei with 54 < Z < 64 are expected to be quite deformed in their ground state and their study is an important input for the theoretical models that describe this kind of decay. Our studies have brought, as first result, the discovery of the decay by pemission of 117La where to p-decaying levels have been found. Our experimental program continued with the study of the decay of 126Pm. For this nucleus we can only conclude that our low statistics data show no evidence of p emission.

  19. Rotating Stall Investigations. Volume 2. Experimental Studies

    DTIC Science & Technology

    1983-01-01

    clear rotating stall once it has started. Separate tests were performed to study the response of the rotating stall control system when a simulated ...days. Each data set was fitted with two curves using the method of least squares. One curve assumed a 9/5 power law for the aerodynamic losses and...these curves which are shown in Fig. 2 fitted to the total torque data. The linear portions of the least square fits to the three sets of data are

  20. 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).

  1. Study of multi-nucleon transfer reactions with light nuclei

    SciTech Connect

    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.

  2. Theoretical Study of Low Energy Scattering from Metal Nuclei.

    NASA Astrophysics Data System (ADS)

    Gomez, Bernadette; Hira, Ajit; Duran, Joe; Jaramillo, Danelle

    2015-04-01

    We continue our interest in the interactions between different nuclear species with a computational study of the scattering of the low-energy nuclei of H through F atoms (Z <= 9 ) from Silver, Palladium and other metals. Recent work has shown that neutron scattering can be used to record holographic images of materials. We have developed a FORTRAN computer program to compute stopping cross sections and scattering angles in Ag and other metals for the small nuclear projectiles, using Monte Carlo calculation. This code allows for different angles of incidence. Next, simulations were done in the energy interval from 50 to 210 keV. The computational results thus obtained are compared with relevant experimental data. The data are further analyzed to identify periodic trends in terms of the atomic number of the projectile. Such studies have potential applications in nuclear physics and in nuclear medicine.

  3. Rotation Studies of Jovian Trojan Asteroids

    NASA Astrophysics Data System (ADS)

    French, Linda M.; Stephens, Robert D.; Wasserman, Lawrence H.; Lederer, Susan M.; Rohl, Derrick A.

    2011-08-01

    The Jovian Trojan asteroids appear to be fundamentally different from main belt asteroids. They formed further from the sun, they are of different composition, and their collisional history is different. Lightcurve studies provide information about the distribution of rotation frequencies of a group of asteroids. For main belt asteroids larger than about 40 km in diameter, the distribution of rotation frequencies is Maxwellian (Pravec et al. 2000). This suggests that collisions determine their rotation properties. Smaller main belt asteroids, however, show a predominance of both fast and slow rotators, with the observed spin distribution apparently controlled by the Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect (Pravec et al. 2008). The Trojans larger than 100 km in diameter have been almost completely sampled, but lightcurves for smaller Trojans have been less well studied due to their low albedos and greater solar distances. We propose to investigate the rotation periods of 4-6 small (D < 50 km) Trojan asteroids and 6-9 Trojans in the 50-100 km size range.

  4. Introduction to the study of collisions between heavy nuclei

    SciTech Connect

    Bayman, B.F.

    1980-01-01

    Current investigations concerning the collisions of nuclei governed by small de Broglie wavelengths are reviewed. The wave packets localize nuclei in regions small compared to their diameters. Cross sections are examined for potential scattering, elastic scattering, quasi-molecular states, peripheral particle-transfer reactions, fusion, and deep inelastic collisions. Theories of fusion and deep inelastic collisions are summarized. This paper is in the nature of a review-tutorial. 45 references, 51 figures, 2 tables. (RWR)

  5. Studying Stellar Rotation and Convection

    NASA Astrophysics Data System (ADS)

    Goupil, Mariejo; Belkacem, Kévin; Neiner, Coralie; Lignières, Francois; Green, John J.

    Based on the lecture notes of a school titled "Tides in Astronomy and Astrophysics" that brought together students and researchers, this book focuses on the fundamental theories of tides at different scales of the universe - from tiny satellites to whole galaxies - and on the most recent developments. It also attempts to place the study of tides in a historical perspective. Starting with a general tutorial on tides, the theme of tides is approached in 9 chapters from many directions. They allow non-experts to pick up a physical intuition and a sense of orders of magnitude in the theory of tides. These carefully prepared lecture notes by leaders in the field include many illustrative figures and drawings. Some even offer a variety of simple back-of the-envelope problems.

  6. 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.

  7. 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.

  8. A study of warm absorbers in active galactic nuclei

    NASA Astrophysics Data System (ADS)

    Ashton, Ceri Ellen

    This thesis explores the 'warm absorber' phenomenon observed in Active Galactic Nuclei (AGN). Warm absorbers are clouds of ionised gas within AGN, that cause absorption at soft X-ray wavelengths. They are observed in half of all Type 1 AGN, hence they play an important part in the framework of our under standing of Active Galactic Nuclei. Observations with the satellite XMM-Newton have given us the highest signal-to-noise data yet. XMM-Newton observations of the quasars PG 1114+445 and PG 1309+355 are studied. Both quasars exhibit evidence for absorption by warm material in the line-of-sight. We define a 'phase' of absorption to have a single ionisation param eter and column density. From fits to the data, the absorption in PG 1114+445 is found to be in two phases, a 'hot' phase with a log ionisation parameter f of 2.57 and a column of 1022 cm-2, and a 'cooler' one with log f of 0.83 and a column of 1021 cm-2. The absorption in PG 1309+355 consists of a single phase, with log f of 1.87 and a column of 1021 cm-2. The absorbing gas lies at distances of 1019 - 1022 cm from the continuum radiation sources in these AGN, suggesting origins in a wind emanating from a molecular torus, according to the 'Standard Model' of AGN. The kinetic luminosities of the outflowing absorbers represent insignificant fractions (< 10 3) of the energy budgets of the AGN. Using data for the Seyfert 1 H 0557 385, the warm absorption is characterised by two phases, a phase with log £ of 0.48 and a column of 1021 cm-2, and a phase with log f of 1.63 and a column of 1022 cm-2. Neutral absorption is also present in the source, and possible origins for this are discussed. For a large sample, observations of warm absorbers are collated and compared with models.

  9. MOJAVE: MONITORING OF JETS IN ACTIVE GALACTIC NUCLEI WITH VLBA EXPERIMENTS. VIII. FARADAY ROTATION IN PARSEC-SCALE AGN JETS

    SciTech Connect

    Hovatta, Talvikki; Lister, Matthew L.; Aller, Margo F.; Aller, Hugh D.; Homan, Daniel C.; Kovalev, Yuri Y.

    2012-10-01

    We report observations of Faraday rotation measures for a sample of 191 extragalactic radio jets observed within the MOJAVE program. Multifrequency Very Long Baseline Array observations were carried out over 12 epochs in 2006 at four frequencies between 8 and 15 GHz. We detect parsec-scale Faraday rotation measures in 149 sources and find the quasars to have larger rotation measures on average than BL Lac objects. The median core rotation measures are significantly higher than in the jet components. This is especially true for quasars where we detect a significant negative correlation between the magnitude of the rotation measure and the de-projected distance from the core. We perform detailed simulations of the observational errors of total intensity, polarization, and Faraday rotation, and concentrate on the errors of transverse Faraday rotation measure gradients in unresolved jets. Our simulations show that the finite image restoring beam size has a significant effect on the observed rotation measure gradients, and spurious gradients can occur due to noise in the data if the jet is less than two beams wide in polarization. We detect significant transverse rotation measure gradients in four sources (0923+392, 1226+023, 2230+114, and 2251+158). In 1226+023 the rotation measure is for the first time seen to change sign from positive to negative over the transverse cuts, which supports the presence of a helical magnetic field in the jet. In this source we also detect variations in the jet rotation measure over a timescale of three months, which are difficult to explain with external Faraday screens and suggest internal Faraday rotation. By comparing fractional polarization changes in jet components between the four frequency bands to depolarization models, we find that an external purely random Faraday screen viewed through only a few lines of sight can explain most of our polarization observations, but in some sources, such as 1226+023 and 2251+158, internal

  10. A Compact Rotating 1K Cryostat for Helium 4 Studies

    NASA Astrophysics Data System (ADS)

    Makiuchi, Takahiko; Murakawa, Satoshi; Shirahama, Keiya

    2017-06-01

    Recent studies of rotating superfluid ^3He and ^4He had led to construct massive rotating refrigerators. We have built, on the other hand, a compact, inexpensive and easily operated rotating cryostat for search for novel superfluid phenomena. Our new rotating cryostat is so simple that one operator can handle it and make continuous measurements. The cryostat and electronic devices are rotated as a whole by a servomotor directly attached underneath. The maximal rotation angular velocity is 6.28 rad/s, which is an intermediate value in existing rotating cryostats. The performance during rotation is discussed.

  11. A Compact Rotating 1K Cryostat for Helium 4 Studies

    NASA Astrophysics Data System (ADS)

    Makiuchi, Takahiko; Murakawa, Satoshi; Shirahama, Keiya

    2016-11-01

    Recent studies of rotating superfluid ^3 He and ^4 He had led to construct massive rotating refrigerators. We have built, on the other hand, a compact, inexpensive and easily operated rotating cryostat for search for novel superfluid phenomena. Our new rotating cryostat is so simple that one operator can handle it and make continuous measurements. The cryostat and electronic devices are rotated as a whole by a servomotor directly attached underneath. The maximal rotation angular velocity is 6.28 rad/s, which is an intermediate value in existing rotating cryostats. The performance during rotation is discussed.

  12. 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.

  13. Continuum studies in Gd nuclei by particle- γ coincidences

    NASA Astrophysics Data System (ADS)

    Ross, T. J.; Hughes, R. O.; Beausang, C. W.; Allmond, J. M.; Burke, J. T.; Phair, L. W.; Scielzo, N.; 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.

    2011-04-01

    An experiment was carried out at the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory to study Gd isotopes in the vicinity of the N=90 transitional region. A 25 MeV proton beam was incident on 158 / 155 / 154Gd targets and used to populate states in 152-158Gd by (p,p'), (p,d) and (p,t) reactions. The exit channel is selected by gating on charged particles using the STARS Si-Telescope array, which also gives the excitation energy of the residual nucleus. Coincident γ information is obtained using the LIBERACE Clover array. Particle- γ coincidences provide a powerful tool for probing the residual nucleus [1]. For example, particles in coincidence with a specific γ ray produce a spectrum representing all levels populated in the nucleus that subsequently decay into the state from which the γ ray originates. Results will be presented that give an insight into the population distribution of the high level density region above the pair gap in the even-even Gd nuclei via light ion reactions.

  14. α -decay chains of recoiled superheavy nuclei: A theoretical study

    NASA Astrophysics Data System (ADS)

    Niyti, Sawhney, Gudveen; Sharma, Manoj K.; Gupta, Raj K.

    2015-05-01

    A systematic theoretical study of α -decay half-lives in the superheavy mass region of the periodic table of elements is carried out by extending the quantum-mechanical fragmentation theory based on the preformed cluster model (PCM) to include temperature (T ) dependence in its built-in preformation and penetration probabilities of decay fragments. Earlier, the α -decay chains of the isotopes of Z =115 were investigated by using the standard PCM for spontaneous decays, with"hot-optimum" orientation effects included, which required a constant scaling factor of 104 to approach the available experimental data. In the present approach of the PCM (T ≠0 ), the temperature effects are included via the recoil energy of the residual superheavy nucleus (SHN) left after x -neutron emission from the superheavy compound nucleus. The important result is that the α -decay half-lives calculated by the PCM (T ≠0 ) match the experimental data nearly exactly, without using any scaling factor of the type used in the PCM. Note that the PCM (T ≠0 ) is an equivalent of the dynamical cluster-decay model for heavy-ion collisions at angular momentum ℓ =0 . The only parameter of model is the neck-length parameter Δ R , which for the calculated half-lives of α -decay chains of various isotopes of Z =113 to 118 nuclei formed in "hot-fusion" reactions is found to be nearly constant, i.e., Δ R ≈0.95 ±0.05 fm for all the α -decay chains studied. The use of recoiled residue nucleus as a secondary heavy-ion beam for nuclear reactions has also been suggested in the past.

  15. Commissioning a Rotating Target Wheel Assembly for Heavy Element Studies

    NASA Astrophysics Data System (ADS)

    Fields, L. D.; Bennett, M. E.; Mayorov, D. A.; Folden, C. M.

    2013-10-01

    The heaviest elements are produced artificially by fusing nuclei of light elements within an accelerator to form heavier nuclei. The most direct method to increase the production rate of nuclei is to increase the beam intensity, necessitating the use of a rotating target to minimize damage to the target by deposited heat. Such a target wheel was constructed for heavy element research at Texas A&M University, Cyclotron Institute, consisting of a wheel with three banana-shaped target cutouts. The target is designed to rotate at 1700 rpm, and a fiber optic cable provides a signal to trigger beam pulsing in order to avoid irradiating the spokes between target segments. Following minor mechanical modifications and construction of a dedicated electrical panel, the rotating target assembly was commissioned for a beam experiment. A 15 MeV/u beam of 20Ne was delivered from the K500 cyclotron and detected by a ruggedized silicon detector. The beam pulsing response time was characterized as a function of the rational frequency of the target wheel. Preliminary analysis suggests that the K500 is capable of pulsing at rates of up to 250 Hz, which is sufficient for planned future experiments. Funded by DOE and NSF-REU Program.

  16. Superheavy Nuclei: Which Regions of Nuclear Map are Accessible for the Nearest Studies

    NASA Astrophysics Data System (ADS)

    Karpov, A. V.; Zagrebaev, V. I.; Greiner, W.

    2015-11-01

    Use of fusion reactions for synthesis and studying new superheavy nuclei is considered in the paper. Perspectives of synthesis of new elements with Z > 118 are discussed. The gap of unknown SH nuclei, located between the isotopes which were produced earlier in the cold and hot fusion reactions, can be filled in fusion reactions of 48Ca with available lighter isotopes of Pu, Am, and Cm. Cross sections for the production of these nuclei are predicted to be rather large. The found area of β+-decaying SH nuclei with 111 ≤ Z ≤ 115 located to the "right" (more neutron-rich) to those synthesized recently in Dubna in 48Ca-induced fusion reactions gives a unique chance to synthesize in fusion reactions the most stable SH nuclei located at the center of the island of stability.

  17. Studies of nuclei separated by zonal centrifugation from liver of rats treated with thioacetamide

    PubMed Central

    Gonzalez-Mujica, F.; Mathias, A. P.

    1973-01-01

    1. The effects of the inclusion of thioacetamide in the diet on the properties of rat liver nuclei were studied both in adolescent rats, in which the parenchymal cells contain diploid nuclei, and in young adult rats, with a high proportion of tetraploid nuclei. 2. These investigations included a survey of the sedimentation properties of the nuclei, the nuclear volumes, content of DNA, RNA and protein, the incorporation in vivo of [3H]thymidine into DNA and [14C]orotate into RNA, and measurements of the activity of RNA polymerase and ribonuclease. These studies were conducted on nuclei fractionated by zonal centrifugation. 3. In both groups of animals, exposure to thioacetamide produced large numbers of nuclei that were abnormal in their chemical composition and enzymic activity. The changes were complex as regards both the types of nuclei that were affected and in their variation with time. 4. In adolescent rats two waves of synthesis of DNA and RNA were observed, one at 3 days and the other after 2 weeks of treatment. The first decline in the incorporations into both DNA and RNA coincided with a decrease in the pool sizes of some of the precursors. The activity of RNA polymerase was not substantially altered. A marked increase in the content of protein was observed before the first wave of synthesis. The normal progressive increase in tetraploid nuclei was prevented. 5. In young adult rats two waves of DNA synthesis were detected. Each was preceded by a large increase in the amount of protein per nucleus but was not accompanied by increased RNA synthesis. After 4 weeks of treatment, the diploid stromal nuclei appeared mainly unaffected and large numbers of tetraploid nuclei with a greatly increased quantity of protein were observed. PMID:4353443

  18. Studies of the Shapes of Heavy Nuclei at ISOLDE

    NASA Astrophysics Data System (ADS)

    Butler, Peter A.

    For certain combinations of protons and neutrons there is a theoretical expectation that the shape of nuclei can assume octupole deformation, which would give rise to reflection asymmetry or a "pear-shape" in the intrinsic frame, either dynamically (octupole vibrations) or statically (permanent octupole deformation). In this talk I will briefly review the historic evidence for reflection asymmetry in nuclei and describe how recent experiments carried out at REX-ISOLDE have constrained nuclear theory and how they contribute to tests of extensions of the Standard Model. I will also discuss future prospects for measuring nuclear shapes from Coulomb Excitation: experiments are being planned that will exploit beams from HIE-ISOLDE that are cooled in the TSR storage ring and injected into a solenoidal spectrometer similar to the HELIOS device developed at the Argonne National Laboratory.

  19. Studies of Icy Bodies: Uranian Satellites and Cometary Nuclei

    NASA Technical Reports Server (NTRS)

    Squyres, S. W.; Reynolds, R. T.

    1985-01-01

    The evolution and structure of icy bodies of the solar system are summarized. The effect of tidal evolution, eccentricities, and decay time on Titania, Oberon, Miranda, Umbriel and Ariel is discussed. Observational measurements of the masses and radii of these satellites have recently become sufficiently reliable to use in investigation. Also considered is the problem of the sub-surface temperature distribution and heat transfer of icy comet nuclei.

  20. Near infrared study of shrouded active galactic nuclei

    NASA Astrophysics Data System (ADS)

    Hearty, Frederick R.

    2007-08-01

    In this work, I consider the astronomical search for active galactic nuclei which has been predominately conducted in the optical portion of the electromagnetic spectrum and propose a multi-wavelength approach. I describe the opto-mechanical systems of the Near Infrared Camera and Fabry-Perot Spectrometer (NIC-FPS) which I, as part of a team, designed, built, and commissioned, and which I then used for this scientific investigation. This investigation had two purposes: (1) to demonstrate the state-of-theart capability of NIC-FPS, and (2) to examine the large population of astronomical radio sources that remain undetected in optical observations. My broadband near infrared imaging, when combined with archival optical, mid-infrared, and radio data, revealed large numbers of active galactic nuclei and related quasi- stellar objects which may, in part, be hidden by shrouds of gas and dust. This newly revealed population is likely to outnumber the optically selected population, and may indicate a phase of galactic nuclear activation which has been strongly selected against by existing surveys. Such objects are critical to our scientific understanding because they can be used as probes of the most distant regions of the observable Universe. Additionally, I propose a life cycle model for active galactic nuclei which accounts for the shrouded phase and for the disparity between the optically detected and near infrared detected radio sources.

  1. Comparative anatomical studies on the cerebellar nuclei of the pangolins.

    PubMed

    Ishimoto, Y

    1983-01-01

    The configurations and volumes of the cerebellar nuclei of left and right 10 sides of 5 cases of the pangolins (Manis pentadactyla) were examined with sagittal myelin sheath and toluidine blue stained serial sections and reconstruction models based upon these serial sections respectively. The cerebellar nuclei of the pangolins, same as in other mammals can be divided into four nuclei, nucleus medialis (M), nucleus interpositus posterior (P), nucleus interpositus anterior (A) and nucleus lateralis (L). In all cases from medially to laterally, M, P, A and L appear in order and disappear M, A, P and L in order respectively. The volume of each nucleus in the total volume of the cerebellar nuclei is: M; 5.3-7.9% P; 27.1-31.2% A; 17.6-22.9% L; 42.4-46.2% In right and left each cerebellar nuclei significant difference is not recognized as p is less than 0.05. The posterior protuberance of the nucleus medialis protrudes remarkably in 4 cases of No. 1, No. 2, No. 3 and No. 4 but in only 1 case of No. 5 it protrudes slightly. In nucleus interpositus posterior the ventrolateral protuberance protrudes slightly in 4 cases of No. 1, No. 3, No. 4 and No. 5 but in only 1 case of No. 2 it protrudes remarkably. The anterior protuberance protrudes remarkably in all cases and the superior protuberance protrudes remarkably in 3 cases of No. 2, No. 3 and No. 4 but in 2 cases of No. 1 and No. 5 it protrudes slightly. In sulci, sulcus b and sulcus a' are distinct in all cases and sulcus a, sulcus c, sulcus b' and sulcus c' are considerably remarkable. In the toluidine blue stained serial sections, the nucleus medialis is composed of close small nerve cells, nucleus interpositus posterior is composed of the diffuse medium-sized nerve cells, nucleus interpositus anterior is composed of the close medium-sized nerve cells and nucleus lateralis is composed of the diffuse large nerve cells. In projection pictures of each subnuclei to the cerebellar cortex in each directions in the dorsal view

  2. Neutron-Proton Pairing Correlation for the Rotational Motion of N = Z 72Kr, 76Sr, and 80Zr Nuclei

    NASA Astrophysics Data System (ADS)

    Roy, Prianka; Dhiman, Shashi K.

    The high-spin state properties of the neutron-proton (np) residual effective interaction are analyzed in N = Z 72Kr, 76Sr, and 80Zr nuclei. The self-consistent microscopic Hartree-Fock-Bogoliubov (HFB) equations have been solved by employing monopole corrected two-body effective interaction. A band crossing is observed in 72Kr nucleus at J = 14ℏ state with monopole corrected "HPU1" and "HPU2" effective interactions. The VAP-HFB theory suggests that the "4p-4h" excitations by np residual interaction are the essential ingredients of the mean-field description of the occurence of backbending in 72Kr nucleus.

  3. Configurations of nuclei in Au-catalyzed Si nanowire growth: a first-principles study

    NASA Astrophysics Data System (ADS)

    Yao, Luchi; Zhou, Xiaohao; Chen, Xiaoshuang

    2016-10-01

    The configurations of nuclei in Au catalyzed Si nanowire growth were investigated through an ab-initio thermodynamic-combined approach. We discussed the relation between the configurations and formation energies of the lateral walls of the nucleus in nanowire growth numerically by the classical nucleation theory. The nucleation model was parameterized by the formation energies of surfaces, interfaces and steps calculated in first-principles methods. The configurations of the nuclei were determined by the Wulff theorem. Moreover, we found configurations of the nuclei are different in two different Si-Au contact structures. This study provides an important basis to understand the step-flow process in nanowire growth.

  4. Role of triaxiality in 76Ge and 76Se nuclei studied with Gogny energy density functionals

    NASA Astrophysics Data System (ADS)

    Rodríguez, Tomás R.

    2017-03-01

    The structure of the nuclei 76Ge and 76Se is studied with symmetry conserving configuration mixing methods based on the Gogny D1S interaction. These two nuclei are of key importance in the search for neutrinoless double-beta decay. The energy density functionals used here include symmetry restorations (particle number and angular momentum) and shape mixing within the generator coordinate method. The comparison with the experimental data shows a good qualitative agreement when triaxial shapes are included, revealing the important role played by this degree of freedom in these two nuclei.

  5. The study of the physics of cometary nuclei

    NASA Technical Reports Server (NTRS)

    Whipple, F. L.; Marsden, B. G.; Sekanina, Z.

    1976-01-01

    A semiannual progress report describing the work completed during the period 1 September 1975 to 29 February 1976 on the physics of cometary nuclei was given. The following items were discussed: (1) a paper entitled ""A speculation about comets and the earth'', (2) a chapter entitled"" The physics of comets'' for ""Reviews of Astronomy and Astrophysics'', (3) continuing work on split comets, and (4) results dealing with a new application of nongravitational solar-radial forces as a measure of comet nucleus dimensions and activity.

  6. Rotational properties of N Almost-Equal-To Z nuclei in the presence of neutron-proton correlations

    SciTech Connect

    Sitdikov, A. S. Nikitin, A. S.; Khamzin, A. A.

    2008-02-15

    In the Hartree-Fock-Bogolyubov approximation, the cranking model is formulated with allowance for residual neutron-proton correlations whose interaction has a Gaussian form. The behavior of quasiparticle levels versus the frequency of rotation of the even-even isotopes {sup 72-76}Kr is investigated within this approach.

  7. Rotation and shape changes in Tb151 and Pb196: Probes of nuclear structure and tunneling process in warm nuclei. I. Experimental analysis

    NASA Astrophysics Data System (ADS)

    Leoni, S.; Benzoni, G.; Blasi, N.; Bracco, A.; Camera, F.; Corsi, A.; Crespi, F. C. L.; Mason, P.; Million, B.; Montanari, D.; Pignanelli, M.; Vigezzi, E.; Wieland, O.; Matsuo, M.; Shimizu, Y. R.; Curien, D.; Duchêne, G.; Robin, J.; Bednarczyk, P.; Castoldi, M.; Herskind, B.; Kmiecik, M.; Maj, A.; Meczynski, W.; Styczen, J.; Zieblinski, M.; Zuber, K.; Zucchiatti, A.

    2009-06-01

    The γ decay associated with the warm rotation of the superdeformed nuclei Tb151 and Pb196 has been measured with the Euroball IV array. Several experimental quantities are presented, putting strong constraints on the decay dynamics in the superdeformed well. The data are successfully reproduced using a Monte Carlo simulation of the γ decay based on microscopically calculated energy levels, E2 decay probabilities, collective mass parameters, and potential energy barriers between the wells associated with normal and super deformation. This allows one to test the basic ingredients of the physical process, such as the strength of the two-body residual interaction and the potential barriers as a function of spin and excitation energy. We also show that the data probe the E1 strength function, indicating an enhancement around 1-2 MeV γ rays, which might be related to octupole vibrations.

  8. Rotation and shape changes in {sup 151}Tb and {sup 196}Pb: Probes of nuclear structure and tunneling process in warm nuclei. I. Experimental analysis

    SciTech Connect

    Leoni, S.; Bracco, A.; Camera, F.; Corsi, A.; Crespi, F. C. L.; Montanari, D.; Pignanelli, M.; Benzoni, G.; Blasi, N.; Million, B.; Vigezzi, E.; Wieland, O.; Mason, P.; Matsuo, M.; Shimizu, Y. R.; Curien, D.; Duchene, G.; Robin, J.; Bednarczyk, P.; Kmiecik, M.

    2009-06-15

    The {gamma} decay associated with the warm rotation of the superdeformed nuclei {sup 151}Tb and {sup 196}Pb has been measured with the Euroball IV array. Several experimental quantities are presented, putting strong constraints on the decay dynamics in the superdeformed well. The data are successfully reproduced using a Monte Carlo simulation of the {gamma} decay based on microscopically calculated energy levels, E2 decay probabilities, collective mass parameters, and potential energy barriers between the wells associated with normal and super deformation. This allows one to test the basic ingredients of the physical process, such as the strength of the two-body residual interaction and the potential barriers as a function of spin and excitation energy. We also show that the data probe the E1 strength function, indicating an enhancement around 1-2 MeV {gamma} rays, which might be related to octupole vibrations.

  9. Climate model studies of synchronously rotating planets.

    PubMed

    Joshi, Manoj

    2003-01-01

    M stars constitute 75% of main sequence stars though, until recently, their star systems have not been considered suitable places for habitable planets to exist. In this study the climate of a synchronously rotating planet around an M dwarf star is evaluated using a three-dimensional global atmospheric circulation model. The presence of clouds and evaporative cooling at the surface of the planet result in a cooler surface temperature at the subsolar point. Water ice forms at the polar regions and on the dark side, where the minimum temperature lies between -30 degrees C and 0 degrees C. As expected, rainfall is extremely high on the starlit side and extremely low on the dark side. The presence of a dry continent causes higher temperatures on the dayside, and allows accumulation of snow on the nightside. The absence of any oceans leads to higher day-night temperature differences, consistent with previous work. The present study reinforces recent conclusions that synchronously rotating planets within the circumstellar habitable zones of M dwarf stars should be habitable, and therefore M dwarf systems should not be excluded in future searches for exoplanets.

  10. Rotations

    Treesearch

    John R. Jones; Wayne D. Shepperd

    1985-01-01

    The rotation, in forestry, is the planned number of years between formation of a crop or stand and its final harvest at a specified stage of maturity (Ford-Robertson 1971). The rotation used for many species is the age of culmination of mean usable volume growth [net mean annual increment (MAI)]. At that age, usable volume divided by age reaches its highest level. That...

  11. Comparative study of icy patches on comet nuclei

    NASA Astrophysics Data System (ADS)

    Oklay, Nilda; Pommerol, Antoine; Barucci, Maria Antonietta; Sunshine, Jessica; Sierks, Holger; Pajola, Maurizio

    2016-07-01

    Cometary missions Deep Impact, EPOXI and Rosetta investigated the nuclei of comets 9P/Tempel 1, 103P/Hartley 2 and 67P/Churyumov-Gerasimenko respectively. Bright patches were observed on the surfaces of each of these three comets [1-5]. Of these, the surface of 67P is mapped at the highest spatial resolution via narrow angle camera (NAC) of the Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS, [6]) on board the Rosetta spacecraft. OSIRIS NAC is equipped with twelve filters covering the wavelength range of 250 nm to 1000 nm. Various filters combinations are used during surface mapping. With high spatial resolution data of comet 67P, three types of bright features were detected on the comet surface: Clustered, isolated and bright boulders [2]. In the visible spectral range, clustered bright features on comet 67P display bluer spectral slopes than the average surface [2, 4] while isolated bright features on comet 67P have flat spectra [4]. Icy patches observed on the surface of comets 9P and 103P display bluer spectral slopes than the average surface [1, 5]. Clustered and isolated bright features are blue in the RGB composites generated by using the images taken in NIR, visible and NUV wavelengths [2, 4]. This is valid for the icy patches observed on comets 9P and 103P [1, 5]. Spectroscopic observations of bright patches on comets 9P and 103P confirmed the existence of water [1, 5]. There were more than a hundred of bright features detected on the northern hemisphere of comet 67P [2]. Analysis of those features from both multispectral data and spectroscopic data is an ongoing work. Water ice is detected in eight of the bright features so far [7]. Additionally, spectroscopic observations of two clustered bright features on the surface of comet 67P revealed the existence of water ice [3]. The spectral properties of one of the icy patches were studied by [4] using OSIRIS NAC images and compared with the spectral properties of the active regions observed

  12. Study of Analytic Statistical Model for Decay of Light and Medium Mass Nuclei in Nuclear Fragmentation

    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.

  13. Surface properties of neutron-rich exotic nuclei: A source for studying the nuclear symmetry energy

    SciTech Connect

    Gaidarov, M. K.; Antonov, A. N.; Sarriguren, P.; Moya de Guerra, E.

    2011-09-15

    We study the correlation between the thickness of the neutron skin in finite nuclei and the nuclear symmetry energy for isotopic chains of even-even Ni, Sn, and Pb nuclei in the framework of the deformed self-consistent mean-field Skyrme HF + BCS method. The symmetry energy, the neutron pressure, and the asymmetric compressibility in finite nuclei are calculated within the coherent density fluctuation model using the symmetry energy as a function of density within the Brueckner energy density functional. The mass dependence of the nuclear symmetry energy and the neutron-skin thickness are also studied together with the role of the neutron-proton asymmetry. A correlation between the parameters of the equation of state (symmetry energy and its density slope) and the neutron skin is suggested in the isotopic chains of Ni, Sn, and Pb nuclei.

  14. Constrained Hartree-Fock Theory and Study of Deformed Structures of Closed Shell Nuclei

    NASA Astrophysics Data System (ADS)

    Praharaj, Choudhury

    2016-03-01

    We have studied some N or Z = 50 nuclei in a microscopic model with effective interaction in a reasonably large shell model space. Excitation of particles across 50 shell closure leads to well-deformed excited prolate configurations. The potential energy surfaces of nuclei are studied using Hartree-Fock theory with quadrupole constraint to explore the various deformed configurations of N = 50 nuclei 82Ge , 84Se and 86Kr . Energy spectra are calculated from various intrinsic states using Peierls-Yoccoz angular momentum projection technique. Results of spectra and electromagnetic moments and transitions will be presented for N = 50 nuclei and for Z = 50 114Sn nucleus. Supported by Grant No SB/S2/HEP-06/2013 of DST.

  15. Rotational forceps versus manual rotation and direct forceps: A retrospective cohort study.

    PubMed

    O'Brien, Stephen; Day, Fiona; Lenguerrand, Erik; Cornthwaite, Katie; Edwards, Sian; Siassakos, Dimitrios

    2017-05-01

    Rotational forceps and manual rotation followed by direct forceps are techniques used in the management of malposition of the fetal head in the second stage of labor. However, there is widespread debate regarding their relative safety and utility. We aimed to compare the effectiveness and safety of rotational forceps with manual rotation followed by direct forceps, for management of fetal malposition at full dilation. A retrospective cohort study in a single tertiary obstetric unit with >6000 births per year. We recorded and analysed outcomes of 104 sequential rotational forceps births over 21 months (Jan 2010-Sept 2012) and 208 matched chronologically sequential attempted manual rotations and direct forceps births (1:2 by number). Univariable and multivariable approaches used for statistical analysis. The main outcome measure was vaginal birth. The rate of vaginal birth was significantly higher with rotational forceps than with manual rotation followed by direct forceps (88.5% vs 82.2%, RR 1.17, 95% CI 1.04-1.31, p=0.017). Births by rotational forceps were associated with a significantly higher rate of shoulder dystocia (19.2% vs 10.6%, RR 2.35, 95% CI 1.23-4.47, p=0.012), but not of neonatal injury. There were no significant differences in all other maternal and neonatal outcomes between the two modes of birth. The use of rotational forceps was associated with a statistically significantly higher rate of vaginal birth, but also of shoulder dystocia, compared to manual rotation followed by direct forceps. This is the first study to demonstrate a statistically significant increase in the rate of shoulder dystocia following rotational forceps birth. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Studies of craniofacial development in rotating bioreactors.

    PubMed

    Duke, P J; Williams, P; Horn, N; Iverson, J; Leonhart, V; Kong, J; Montufar-Solis, D

    2007-07-01

    Several studies in our laboratory assessed the effect of 3-D culture in various rotating bioreactors on craniofacial development. Initially, mouse first branchial arches were cultured. Molar and incisor development occurred in both upper and lower jaws, but maxilla development was deficient because no brain was present. In a second study using excised whole heads, the oral epithelia fused and teeth did not develop. External structure of the face was obliterated, although internally, eye development was excellent. To preserve both internal spaces and external face structure, subsequent experiments used heads encapsulated in alginate. Teeth developed in these heads, though some interior components were necrotic. Additional experiments used older embryos, with already initiated structures, and less concentrated alginate. Orientation and unreserved identification of structures remain unresolved issues. Future studies will identify structures of interest using transcription factors unique to these structures at particular stages of fetal development.

  17. Structure of Light Neutron-rich Nuclei Studied with Transfer Reactions

    SciTech Connect

    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.

  18. Systematic study of iodine nuclei in A∼125 mass region

    SciTech Connect

    Sharma, H. P.; Chakraborty, S.; Kumar, A.; Banerjee, P.; Ganguly, S.; Muralithar, S.; Singh, R. P.; Kumar, A.; Kaur, N.; Kumar, S.; Chaturvedi, L.; Jain, A. K.; Laxminarayan, S.

    2014-08-14

    Excited states of {sup 127}I were populated via {sup 124}Sn({sup 7}Li,{sup 4}nγ){sup 127}I fusion-evaporation reaction at beam energy of 33 MeV. Multipolarities of several transitions were determined and spins of corresponding states have been confirmed. The band-head spin and parity of an already reported band at 2901.2 keV has been confirmed. Based on the observed characteristic features and by comparing with the systematics of odd mass iodine nuclei, a πg{sub 7/2}⊗νh{sub 11/2}{sup 2} configuration has been proposed for this band. The experimental B(M1)/B(E2) values for πg{sub 7/2} band were compared with the theoretical results of semi classical model of Frauendorf and Donau and found in well agreement.

  19. Systematic study of iodine nuclei in A˜125 mass region

    NASA Astrophysics Data System (ADS)

    Sharma, H. P.; Chakraborty, S.; Banerjee, P.; Ganguly, S.; Muralithar, S.; Singh, R. P.; Kumar, A.; Kaur, N.; Kumar, S.; Kumar, A.; Chaturvedi, L.; Jain, A. K.; Laxminarayan, S.

    2014-08-01

    Excited states of 127I were populated via 124Sn(7Li,4nγ)127I fusion-evaporation reaction at beam energy of 33 MeV. Multipolarities of several transitions were determined and spins of corresponding states have been confirmed. The band-head spin and parity of an already reported band at 2901.2 keV has been confirmed. Based on the observed characteristic features and by comparing with the systematics of odd mass iodine nuclei, a πg7/2⊗νh11/22 configuration has been proposed for this band. The experimental B(M1)/B(E2) values for πg7/2 band were compared with the theoretical results of semi classical model of Frauendorf and Donau and found in well agreement.

  20. A NICMOS Study of Merging Nuclei in the Toomre Sequence: Finding Order Amid Chaos

    NASA Astrophysics Data System (ADS)

    Laine, Seppo

    2002-07-01

    The final death throes of merging spiral galaxy nuclei are hidden behind dusty maelstroms of colliding gas clouds and glaring star formation activity. The dynamically important centers of mass can only be uncovered by imaging at NIR wavelengths and with the high spatial resolution of HST. We propose a near-infrared imaging program to inspect the physical processes of merging at spatial scales of ~100 pc. The Toomre Sequence provides the best sample of merging galaxies for such a study, because it has been studied extensively from the ground, and the global properties are well understood. Our previous Cycle 9 WFPC2 images of the nuclei have revealed a wealth of information on star forming activity and dust, but based on those data alone it is impossible to determine the locations of the current centers of mass. Determining the mass centers and stellar density profiles is important for understanding both the kinematics and the dynamical evolution of the nuclei, and the formation of nuclear density cusps in galaxies. We propose J, H and K band imaging of the nuclei in early and intermediate stage mergers in the Toomre Sequence. Because of the much reduced effect of dust extinction, the near-infrared images are also optimally suited to searches for nuclear rings and bars around the nuclei. Combined with our ongoing Cycle 9 program, these data will provide a detailed view of the structure and evolution of a sequence of merger nuclei.

  1. Experimental and analytical study of rotating cavitation

    SciTech Connect

    Kamijo, Kenjiro; Shimura, Takashi; Tsujimoto, Yoshinobu

    1994-12-31

    This paper describes experimental and analytical results of rotating cavitation. There are four major sections in this paper. The first section presents the main characteristics of rotating cavitation which was found in the inducer test using a water tunnel. The second section describes the rotating cavitation which occurred in the development test of an LE-7 liquid oxygen pump for the H-II rocket. Also described in this section is how the rotating cavitation was suppressed. The rotating cavitation was the cause of both super synchronous shaft vibration and an unstable head coefficient curve. The third section presents how the theory of rotating cavitation was developed. The final section shows the measured cavitation compliance and mass flow gain factor of the LE-7 pump inducer for comparison of the experimental and analytical results of the rotating cavitation of the LE-7 pump inducer. Almost all the information presented in this paper has already been reported by Kamijo et al. (1977, 1980, 1993, 1993) and by Shimura (1993). In the present paper, the authors attempt to combine and give a clear overview of the experimental and analytical results described in the previous papers to systematically show their experience and findings on rotating cavitation.

  2. Projected shell model study of odd-odd f-p-g shell proton-rich nuclei

    NASA Astrophysics Data System (ADS)

    Palit, R.; Sheikh, J. A.; Sun, Y.; Jain, H. C.

    2003-01-01

    A systematic study of two-quasiparticle bands of the proton-rich odd-odd nuclei in the mass A˜70 80 region is performed using the projected shell model approach. The study includes Br, Rb, and Y isotopes with N=Z+2 and Z+4. We describe the energy spectra and electromagnetic transition strengths in terms of the configuration mixing of the angular-momentum projected multi-quasiparticle states. Signature splitting and signature inversion in the rotational bands are discussed and are shown to be well described. A preliminary study of the odd-odd N=Z nucleus 74Rb, using the concept of spontaneous symmetry breaking is also presented.

  3. Full pf shell model study of A=48 nuclei

    NASA Astrophysics Data System (ADS)

    Caurier, E.; Zuker, A. P.; Poves, A.; Martínez-Pinedo, G.

    1994-07-01

    Exact diagonalizations with a minimally modified realistic force lead to detailed agreement with measured level schemes and electromagnetic transitions in 48Ca, 48Sc, 48Ti, 48V, 48Cr, and 48Mn. Gamow-Teller strength functions are systematically calculated and reproduce the data to within the standard quenching factor. Their fine structure indicates that fragmentation makes much strength unobservable. As a by-product, the calculations suggest a microscopic description of the onset of rotational motion. The spectroscopic quality of the results provides strong arguments in favor of the general validity of monopole corrected realistic forces, which is discussed.

  4. Continuum radiation from active galactic nuclei: A statistical study

    NASA Technical Reports Server (NTRS)

    Isobe, T.; Feigelson, E. D.; Singh, K. P.; Kembhavi, A.

    1986-01-01

    The physics of the continuum spectrum of active galactic nuclei (AGNs) was examined using a large data set and rigorous statistical methods. A data base was constructed for 469 objects which include radio selected quasars, optically selected quasars, X-ray selected AGNs, BL Lac objects, and optically unidentified compact radio sources. Each object has measurements of its radio, optical, X-ray core continuum luminosity, though many of them are upper limits. Since many radio sources have extended components, the core component were carefully selected out from the total radio luminosity. With survival analysis statistical methods, which can treat upper limits correctly, these data can yield better statistical results than those previously obtained. A variety of statistical tests are performed, such as the comparison of the luminosity functions in different subsamples, and linear regressions of luminosities in different bands. Interpretation of the results leads to the following tentative conclusions: the main emission mechanism of optically selected quasars and X-ray selected AGNs is thermal, while that of BL Lac objects is synchrotron; radio selected quasars may have two different emission mechanisms in the X-ray band; BL Lac objects appear to be special cases of the radio selected quasars; some compact radio sources show the possibility of synchrotron self-Compton (SSC) in the optical band; and the spectral index between the optical and the X-ray bands depends on the optical luminosity.

  5. Neural basis for eye velocity generation in the vestibular nuclei of alert monkeys during off-vertical axis rotation.

    PubMed

    Reisine, H; Raphan, T

    1992-01-01

    Activity of "vestibular only" (VO) and "vestibular plus saccade" (VPS) units was recorded in the rostral part of the medial vestibular nucleus and caudal part of the superior vestibular nucleus of alert rhesus monkeys. By estimating the "null axes" of recorded units (n = 79), the optimal plane of activation was approximately the mean plane of reciprocal semicircular canals, i.e., lateral canals, left anterior-right posterior (LARP) canals or right anterior-left posterior (RALP) canals. All units were excited by rotation in a direction that excited a corresponding ipsilateral semicircular canal. Thus, they all displayed a "type I" response. With the animal upright, there were rapid changes in firing rates of both VO and VPS units in response to steps of angular velocity about a vertical axis. The units were bidirectionally activated during vestibular nystagmus (VN), horizontal optokinetic nystagmus (OKN), optokinetic after-nystagmus (OKAN) and off-vertical axis rotation (OVAR). The rising and falling time constants of the responses to rotation indicated that they were closely linked to velocity storage. There were differences between VPS and VO neurons in that activity of VO units followed the expected time course in response to a stimulus even during periods of drowsiness, when eye velocity was reduced. Firing rates of VPS units, on the other hand, were significantly reduced in the drowsy state. Lateral canal-related units had average firing rates that were linearly related to the bias or steady state level of horizontal eye velocity during OVAR over a range of +/- 60 deg/s. These units could be further divided into two classes according to whether they were modulated during OVAR. Non-modulated units (n = 5) were VO types and all modulated units (n = 5) were VPS types. There was no significant difference between the bias level sensitivities relative to eye velocity of the units with and without modulation (P > 0.05). The modulated units had no sustained change in

  6. Neural basis for eye velocity generation in the vestibular nuclei of alert monkeys during off-vertical axis rotation

    NASA Technical Reports Server (NTRS)

    Reisine, H.; Raphan, T.; Cohen, B. (Principal Investigator)

    1992-01-01

    Activity of "vestibular only" (VO) and "vestibular plus saccade" (VPS) units was recorded in the rostral part of the medial vestibular nucleus and caudal part of the superior vestibular nucleus of alert rhesus monkeys. By estimating the "null axes" of recorded units (n = 79), the optimal plane of activation was approximately the mean plane of reciprocal semicircular canals, i.e., lateral canals, left anterior-right posterior (LARP) canals or right anterior-left posterior (RALP) canals. All units were excited by rotation in a direction that excited a corresponding ipsilateral semicircular canal. Thus, they all displayed a "type I" response. With the animal upright, there were rapid changes in firing rates of both VO and VPS units in response to steps of angular velocity about a vertical axis. The units were bidirectionally activated during vestibular nystagmus (VN), horizontal optokinetic nystagmus (OKN), optokinetic after-nystagmus (OKAN) and off-vertical axis rotation (OVAR). The rising and falling time constants of the responses to rotation indicated that they were closely linked to velocity storage. There were differences between VPS and VO neurons in that activity of VO units followed the expected time course in response to a stimulus even during periods of drowsiness, when eye velocity was reduced. Firing rates of VPS units, on the other hand, were significantly reduced in the drowsy state. Lateral canal-related units had average firing rates that were linearly related to the bias or steady state level of horizontal eye velocity during OVAR over a range of +/- 60 deg/s. These units could be further divided into two classes according to whether they were modulated during OVAR. Non-modulated units (n = 5) were VO types and all modulated units (n = 5) were VPS types. There was no significant difference between the bias level sensitivities relative to eye velocity of the units with and without modulation (P > 0.05). The modulated units had no sustained change in

  7. Neural basis for eye velocity generation in the vestibular nuclei of alert monkeys during off-vertical axis rotation

    NASA Technical Reports Server (NTRS)

    Reisine, H.; Raphan, T.; Cohen, B. (Principal Investigator)

    1992-01-01

    Activity of "vestibular only" (VO) and "vestibular plus saccade" (VPS) units was recorded in the rostral part of the medial vestibular nucleus and caudal part of the superior vestibular nucleus of alert rhesus monkeys. By estimating the "null axes" of recorded units (n = 79), the optimal plane of activation was approximately the mean plane of reciprocal semicircular canals, i.e., lateral canals, left anterior-right posterior (LARP) canals or right anterior-left posterior (RALP) canals. All units were excited by rotation in a direction that excited a corresponding ipsilateral semicircular canal. Thus, they all displayed a "type I" response. With the animal upright, there were rapid changes in firing rates of both VO and VPS units in response to steps of angular velocity about a vertical axis. The units were bidirectionally activated during vestibular nystagmus (VN), horizontal optokinetic nystagmus (OKN), optokinetic after-nystagmus (OKAN) and off-vertical axis rotation (OVAR). The rising and falling time constants of the responses to rotation indicated that they were closely linked to velocity storage. There were differences between VPS and VO neurons in that activity of VO units followed the expected time course in response to a stimulus even during periods of drowsiness, when eye velocity was reduced. Firing rates of VPS units, on the other hand, were significantly reduced in the drowsy state. Lateral canal-related units had average firing rates that were linearly related to the bias or steady state level of horizontal eye velocity during OVAR over a range of +/- 60 deg/s. These units could be further divided into two classes according to whether they were modulated during OVAR. Non-modulated units (n = 5) were VO types and all modulated units (n = 5) were VPS types. There was no significant difference between the bias level sensitivities relative to eye velocity of the units with and without modulation (P > 0.05). The modulated units had no sustained change in

  8. 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.

  9. Studies of chondrogenesis in rotating systems

    NASA Technical Reports Server (NTRS)

    Duke, P. J.; Daane, E. L.; Montufar-Solis, D.

    1993-01-01

    A great deal of energy has been exerted over the years researching methods for regenerating and repairing bone and cartilage. Several techniques, especially bone implants and grafts, show great promise for providing a remedy for many skeletal disorders and chondrodystrophies. The bioreactor (rotating-wall vessel, RWV) is a cell culture system that creates a nurturing environment conducive to cell aggregation. Chondrocyte cultures have been studied as implants for repair and replacement of damaged and missing bone and cartilage since 1965 [Chesterman and Smith, J Bone Joint Surg 50B:184-197, 1965]. The ability to use large, tissue-like cartilage aggregates grown in the RWV would be of great clinical significance in treating skeletal disorders. In addition, the RWV may provide a superior method for studying chondrogenesis and chondrogenic mutations. Because the RWV is also reported to simulate many of the conditions of microgravity it is a very useful ground-based tool for studying how cell systems will react to microgravity.

  10. Studies of chondrogenesis in rotating systems.

    PubMed

    Duke, P J; Daane, E L; Montufar-Solis, D

    1993-03-01

    A great deal of energy has been exerted over the years researching methods for regenerating and repairing bone and cartilage. Several techniques, especially bone implants and grafts, show great promise for providing a remedy for many skeletal disorders and chondrodystrophies. The bioreactor (rotating-wall vessel, RWV) is a cell culture system that creates a nurturing environment conducive to cell aggregation. Chondrocyte cultures have been studied as implants for repair and replacement of damaged and missing bone and cartilage since 1965 [Chesterman and Smith, J Bone Joint Surg 50B:184-197, 1965]. The ability to use large, tissue-like cartilage aggregates grown in the RWV would be of great clinical significance in treating skeletal disorders. In addition, the RWV may provide a superior method for studying chondrogenesis and chondrogenic mutations. Because the RWV is also reported to simulate many of the conditions of microgravity it is a very useful ground-based tool for studying how cell systems will react to microgravity.

  11. Studies of chondrogenesis in rotating systems

    NASA Technical Reports Server (NTRS)

    Duke, P. J.; Daane, E. L.; Montufar-Solis, D.

    1993-01-01

    A great deal of energy has been exerted over the years researching methods for regenerating and repairing bone and cartilage. Several techniques, especially bone implants and grafts, show great promise for providing a remedy for many skeletal disorders and chondrodystrophies. The bioreactor (rotating-wall vessel, RWV) is a cell culture system that creates a nurturing environment conducive to cell aggregation. Chondrocyte cultures have been studied as implants for repair and replacement of damaged and missing bone and cartilage since 1965 [Chesterman and Smith, J Bone Joint Surg 50B:184-197, 1965]. The ability to use large, tissue-like cartilage aggregates grown in the RWV would be of great clinical significance in treating skeletal disorders. In addition, the RWV may provide a superior method for studying chondrogenesis and chondrogenic mutations. Because the RWV is also reported to simulate many of the conditions of microgravity it is a very useful ground-based tool for studying how cell systems will react to microgravity.

  12. Study of Exotic Weakly Bound Nuclei Using Magnetic Analyzer Mavr

    NASA Astrophysics Data System (ADS)

    Maslov, V. A.; Kazacha, V. I.; Kolesov, I. V.; Lukyanov, S. M.; Melnikov, V. N.; Osipov, N. F.; Penionzhkevich, Yu. E.; Skobelev, N. K.; Sobolev, Yu. G.; Voskoboinik, E. I.

    2016-06-01

    A project of the high-resolution magnetic analyzer MAVR is proposed. The analyzer will comprise new magnetic optical and detecting systems for separation and identification of reaction products in a wide range of masses (5-150) and charges (1-60). The magnetic optical system consists of the MSP-144 magnet and a doublet of quadrupole lenses. This will allow the solid angle of the spectrometer to be increased by an order of magnitude up to 30 msr. The magnetic analyzer will have a high momentum resolution (10-4) and high focal-plane dispersion (1.9 m). It will allow products of nuclear reactions at energies up to 30 MeV/nucleon to be detected with the charge resolution ∼1/60. Implementation of the project is divided into two stages: conversion of the magnetic analyzer proper and construction of the nuclear reaction products identification system. The MULTI detecting system is being developed for the MAVR magnetic analyzer to allow detection of nuclear reaction products and their identification by charge Q, atomic number Z, and mass A with a high absolute accuracy. The identification will be performed by measuring the energy loss (ΔE), time of flight (TOF), and total kinetic energy (TKE) of reaction products. The particle trajectories in the analyzer will also be determined using the drift chamber developed jointly with GANIL. The MAVR analyzer will operate in both primary beams of heavy ions and beams of radioactive nuclei produced by the U400 - U400M acceleration complex. It will also be used for measuring energy spectra of nuclear reaction products and as an energy monochromator.

  13. Cerebellar contribution to mental rotation: a cTBS study.

    PubMed

    Picazio, Silvia; Oliveri, Massimiliano; Koch, Giacomo; Caltagirone, Carlo; Petrosini, Laura

    2013-12-01

    A cerebellar role in spatial information processing has been advanced even in the absence of physical manipulation, as occurring in mental rotation. The present study was aimed at investigating the specific involvement of left and right cerebellar hemispheres in two tasks of mental rotation. We used continuous theta burst stimulation to downregulate cerebellar hemisphere excitability in healthy adult subjects performing two mental rotation tasks: an Embodied Mental Rotation (EMR) task, entailing an egocentric strategy, and an Abstract Mental Rotation (AMR) task entailing an allocentric strategy. Following downregulation of left cerebellar hemisphere, reaction times were slower in comparison to sham stimulation in both EMR and AMR tasks. Conversely, identical reaction times were obtained in both tasks following right cerebellar hemisphere and sham stimulations. No effect of cerebellar stimulation side was found on response accuracy. The present findings document a specialization of the left cerebellar hemisphere in mental rotation regardless of the kind of stimulus to be rotated.

  14. Study of Isoscalar Giant Resonances in Exotic Nuclei by Means of Inverse Reactions

    NASA Astrophysics Data System (ADS)

    Harakeh, M. N.

    2015-11-01

    Isoscalar giant resonances in exotic nuclei can be studied using inelastic alpha scattering in inverse kinematics. In particular, the compression modes, i.e. isoscalar giant monopole and dipole resonances, are very interesting because they can furnish information on the different terms of the nuclear incompressibility, especially if measured in long isotopic chains including nuclei far from the valley of stability. As beams of exotic nuclei have relatively low intensities thick targets have to be used in order to get a reasonable yield. However, this leads to degradation of the energy resolution and stops low-energy recoil particles. Two good alternatives exist. The first method is to use an active target, such as MAYA, which is a time-projection chamber and therefore can be used for detection of low-energy recoil particles. Furthermore, its thickness can be increased by increasing the length of the detection volume or the gas pressure without severe loss of energy resolution. The second method is to use a storage ring for storing the exotic nuclei, which then interact with target nuclei from a gas-jet target. Here, the luminosity and hence the yield are increased because the exotic nuclei circulate in the ring at a frequency of around 106 turns/s. Low-energy recoil particles traverse the gas-jet with little loss of energy and can be detected in solid-state detectors. Pioneering experiments with both methods have been performed for inelastic scattering of secondary 56Ni beam off helium nuclei. Here, preliminary results of the experiment with the active target MAYA will be presented.

  15. 18-22 cm VLBA Faraday rotation studies of six AGN jets

    NASA Astrophysics Data System (ADS)

    Motter, J. C.; Gabuzda, D. C.

    2017-05-01

    The formation of relativistic jets in active galactic nuclei (AGN) is related to accretion on to their central supermassive black holes, and magnetic fields are believed to play a central role in launching, collimating and accelerating the jet streams from very compact regions out to kiloparsec or megaparsec scales. In the presence of helical or toroidal magnetic fields threading the AGN jets and their immediate vicinity, gradients in the observed Faraday rotation measures are expected due to the systematic change in the line-of-sight component of the magnetic field across the jet. We have analysed total intensity, linear polarization, fractional polarization and Faraday rotation maps based on very long baseline array data obtained at four wavelengths in the 18-22 cm range for six AGN (OJ 287, 3C 279, PKS 1510-089, 3C 345, BL Lac and 3C 454.3). These observations typically probe projected distances out to tens of parsecs from the observed core, and are well suited for Faraday rotation studies due to the relatively long wavelengths used and the similarity of the structures measured at the different wavelengths. We have identified statistically significant, monotonic, transverse Faraday rotation gradients across the jets of four of these six sources, as well as a tentative transverse Faraday rotation gradient across the jet of OJ 287, providing evidence for the presence of toroidal magnetic fields, which may be one component of helical magnetic fields associated with these AGN jets.

  16. Studies of neutron-rich nuclei far from stability at TRISTAN

    SciTech Connect

    Gill, R.L.

    1984-01-01

    The ISOL facility, TRISTAN, is a user facility located at Brookhaven National Laboratory's High Flux Beam Reactor. Short-lived, neutron-rich nuclei, far from stability, are produced by thermal neutron fission of /sup 235/U. An extensive array of experimental end stations are available for nuclear structure studies. These studies are augmented by a variety of long-lived ion sources suitable for use at a reactor facility. Some recent results at TRISTAN are presented as examples of using an ISOL facility to study series of nuclei, whereby an effective means of conducting nuclear structure investigations is available.

  17. 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.

  18. The study of the physics of cometary nuclei

    NASA Technical Reports Server (NTRS)

    Whipple, F. L.

    1984-01-01

    The observations of comet P/Holmes 1892III, exhibiting two 8 to 10 magnitude bursts, were carefully analyzed. The phenomena are consistent with the grazing encounter of a small satellite with the nucleus. The grazing encounter produced, besides the first great burst, an active area on the nucleus, which was rotating retrograde with a period of 16.3 hr and inclination nearly 180 deg. After the final encounter, the spin period was essentially unchanged, but two areas became active, separated some 164 deg in longitude on the nucleus. After the first burst the total magnitude fell less than two magnitudes, while the nuclear region remained diffuse or complex, rarely if ever showing a stellar appearance. The fading was much more rapid after the second burst (barely naked eye at maximum) while the nucleus frequently stellar after the first day. It seems reasonable to conclude that the grazing encounter distributed a volume of large chunks in the neighborhood of the nucleus, maintaining activity for weeks.

  19. Fluorescence-activated sorting of fixed nuclei: a general method for studying nuclei from specific cell populations that preserves post-translational modifications.

    PubMed

    Marion-Poll, Lucile; Montalban, Enrica; Munier, Annie; Hervé, Denis; Girault, Jean-Antoine

    2014-04-01

    Long-lasting brain alterations that underlie learning and memory are triggered by synaptic activity. How activity can exert long-lasting effects on neurons is a major question in neuroscience. Signalling pathways from cytoplasm to nucleus and the resulting changes in transcription and epigenetic modifications are particularly relevant in this context. However, a major difficulty in their study comes from the cellular heterogeneity of brain tissue. A promising approach is to directly purify identified nuclei. Using mouse striatum we have developed a rapid and efficient method for isolating cell type-specific nuclei from fixed adult brain (fluorescence-activated sorting of fixed nuclei; FAST-FIN). Animals are quickly perfused with a formaldehyde fixative that stops enzymatic reactions and maintains the tissue in the state it was at the time of death, including nuclear localisation of soluble proteins such as GFP and differences in nuclear size between cell types. Tissue is subsequently dissociated with a Dounce homogeniser and nuclei prepared by centrifugation in an iodixanol density gradient. The purified fixed nuclei can then be immunostained with specific antibodies and analysed or sorted by flow cytometry. Simple criteria allow distinction of neurons and non-neuronal cells. Immunolabelling and transgenic mice that express fluorescent proteins can be used to identify specific cell populations, and the nuclei from these populations can be efficiently isolated, even rare cell types such as parvalbumin-expressing interneurons. FAST-FIN allows the preservation and study of dynamic and labile post-translational protein modifications. It should be applicable to other tissues and species, and allow study of DNA and its modifications.

  20. Shape Coexistence in Pb-Rn Nuclei Studied by Particle Decay Spectroscopy

    SciTech Connect

    Andreyev, A. N.

    2006-08-14

    This contribution reviews the results of recent experiments at the velocity filter SHIP (GSI, Darmstadt) in which a number of very neutron-deficient nuclei with Z=83-88 and N< 126 were studied in detail and new nuclides 186,187Po, 192At and 193,194Rn were identified. Complete fusion reactions at beam energies close to the Coulomb barrier were used, followed by particle detection with various detection systems. Peculiarities in {alpha}-decay characteristics of the 186-191Po isotopes are discussed in detail. Very recent results for the neutron-deficient At-Ra nuclei from the gas-filled separator RITU (JYFL, Jyvaeskylae) are also highlighted.The application of a new method to reach nuclei in this region - spallation-evaporation reactions of 238U ions at 1 AGeV on a Be target, followed by the separation with the FRS at GSI is discussed as well.

  1. Nuclear structure studies of medium-mass nuclei using large Ge arrays

    SciTech Connect

    Baktash, C.

    1996-12-31

    The advent of large Ge arrays and their ancillary detectors has greatly advanced spectroscopic studies of the medium-mass nuclei. These nuclei undergo rapid shape changes as a function of spin, excitation energy and particle number and, thus, provide a unique laboratory to test and refine a variety of theoretical models. Following a brief review of the physics motivation, some of the highlights of the experimental results obtained with the help of these powerful detector systems will be discussed. Among results presented here are the newly-discovered island of superdeformation in the A{approximately}80 mass region, and the high-spin band structures in the N{approximately}Z nuclei. These band structures may be understood in the framework of the conventional cranking models, without the introduction of additional T=0 neutron-proton pairing correlations.

  2. Studies in the Phonology of Asian Languages VI: Complex Syllable Nuclei in Vietnamese.

    ERIC Educational Resources Information Center

    Han, Mieko S.

    This study is the sixth in the series "Studies in the Phonology of Asian Languages." A phonetic and phonemic analysis of the three complex nuclei of Vietnames (Hanoi dialect), spelled (1) ye-, -ie-, -ia, (2) -u'o'-, -u'a, and (3) -uo-, -ua, was carried out using the sound spectrograph. The relative domains of the target qualities of the…

  3. Time-dependent Hartree-Fock Study of Octupole Vibrations in doubly magic nuclei

    NASA Astrophysics Data System (ADS)

    Simenel, C.; Buete, J.; Vo-Phuoc, K.

    2016-09-01

    Octupole vibrations are studied in some doubly magic nuclei using the time-dependent Hartree-Fock (TDHF) theory with a Skyrme energy density functional. Through the use of the linear response theory, the energies and transition amplitudes of the low-lying vibrational modes for each of the nuclei were determined. Energies were found to be close to experimental results. However, transition amplitudes, quantified by the deformation parameter β3, are underestimated by TDHF. A comparison with single-particle excitations on the Hartree-Fock ground-state shows that the collective octupole vibrations have their energy lowered due to attractive RPA residual interaction.

  4. THE KEPLER CLUSTER STUDY: STELLAR ROTATION IN NGC 6811

    SciTech Connect

    Meibom, Soeren; Latham, David W.; Dupree, Andrea K.; Furesz, Gabor; Szentgyorgyi, Andrew H.; Buchhave, Lars A.; Barnes, Sydney A.; Batalha, Natalie; Borucki, William J.; Koch, David G.; Jenkins, Jon; Van Cleve, Jeffrey; Haas, Michael R.; Bryson, Stephen T.; Basri, Gibor; Walkowicz, Lucianne M.; Janes, Kenneth A.; Clarke, Bruce D.; Twicken, Joseph D.; Quintana, Elisa V.

    2011-05-20

    We present rotation periods for 71 single dwarf members of the open cluster NGC 6811 determined using photometry from NASA's Kepler mission. The results are the first from The Kepler Cluster Study, which combines Kepler's photometry with ground-based spectroscopy for cluster membership and binarity. The rotation periods delineate a tight sequence in the NGC 6811 color-period diagram from {approx}1 day at mid-F to {approx}11 days at early-K spectral type. This result extends to 1 Gyr similar prior results in the {approx}600 Myr Hyades and Praesepe clusters, suggesting that rotation periods for cool dwarf stars delineate a well-defined surface in the three-dimensional space of color (mass), rotation, and age. It implies that reliable ages can be derived for field dwarf stars with measured colors and rotation periods, and it promises to enable further understanding of various aspects of stellar rotation and activity for cool stars.

  5. Alternating-parity collective states of yrast and nonyrast bands in lanthanide and actinide nuclei

    SciTech Connect

    Nadirbekov, M. S. Yuldasheva, G. A.; Denisov, V. Yu.

    2015-03-15

    Excited collective states of even-even nuclei featuring quadrupole and octupole deformations are studied within a nonadiabatic collective model with a Gaussian potential energy. Rotational states of the yrast band and vibrational-rotational states of nonyrast bands are considered in detail. The energies of alternating-parity excited states of the yrast band in the {sup 164}Er, {sup 220}Ra, and {sup 224}Th nuclei; the yrast and first nonyrast bands in the {sup 154}Sm and {sup 160}Gd nuclei; and the yrast, first nonyrast, and second nonyrast bands in the {sup 224}Ra and {sup 240}Pu nuclei are described well on the basis of the proposed model.

  6. Rotational study of 67P/Churyumov-Gerasimenko

    NASA Astrophysics Data System (ADS)

    Lhotka, C.; Reimond, S.; Souchay, J.; Baur, O.

    2015-10-01

    The aim of the study is to determine the gravity field and moments of inertia along the principal axes of the comet, the obliquity of the axis of rotation with respect to the mean orbital plane, the precession rate, and the nutation coefficients. We also investigate the role of relevant parameters on the rotation.

  7. Job Rotation at Cardiff University Library Service: A Pilot Study

    ERIC Educational Resources Information Center

    Earney, Sally; Martins, Ana

    2009-01-01

    This paper presents case study research of a job rotation pilot involving six library assistants in Cardiff University Library Service (ULS). Firstly, it investigates whether job rotation improves motivation and secondly, whether there is an improvement in skills, both technical and "soft". Following a review of the literature,…

  8. Experimental study of splashing mechanisms by an immersed rotating body

    NASA Astrophysics Data System (ADS)

    Bourgoin, Mickael; Rodriguez, Diego; Gakhar, Saksham; Matas, Jean-Philippe; Berger, Remi

    2016-11-01

    We study the entrainment of water by a rotating wheel, as a function of the rotation frequency, wheel radius and depth of immersion. The entrainment leads to the formation of a liquid sheet on the ascending side, and of ligaments on the descending side. These structures are captured via simple models. We measure via image processing the liquid flux ejected by the wheel.

  9. Study on frozen nuclei in the winter season in the northern mountains of Madrid (Spain)

    NASA Astrophysics Data System (ADS)

    Marcos, J. L.; Sánchez, J. L.; Posada, R.; Gascón, E.; Fernández, S.; Hermida, L.; García-Ortega, E.; López, L.

    2012-04-01

    In the Framework of Studies that the Group for Atmospheric Physics from the University of León has been developing about winter precipitation in the mountains of Madrid, one of the experimental objectives consists of the measurement of concentration (L-1) of frozen nuclei (IN) at the ground level, using an isothermal cloud chamber. The Experimental Center is found in the reservoir in Sierra Guadarrama, located about 50 km north of Madrid, at a height of 1294 meters above sea level. The sample is of 234 days, of which 119 showed precipitation, corresponding to three winter seasons (2008/2009, 2009/2010 and 2010/2011). The chamber is capable of operating at different temperatures. Making use of past experiences, we set the working temperature at -23°C. The principle objectives of the study were, on one hand, to determine the distribution of nuclei concentrations, and on the other, to analyze if this distribution presented similar behaviour, extracting days with precipitation from the sample. The results show that the concentration of nuclei is low. To be exact, on 75% of the days analyzed, this statistic did not exceed 25 L-1. With respect to the second objective described, we saw that the distribution of the concentration stayed very similar in those days in which ground precipitation was registered. In other words, precipitation was not associated with an increase in the number of nuclei. Finally, given the relative proximity of the Experimental Center to the city of Madrid, we took measurements of aerosols to analyze their possible influence on the presence of the nuclei. The results did not allow us to infer a statistically significant relationship between both concentrations. Acknowledgements This study was supported by the following grants: CEN20091028; GRANIMETRO (CGL2010-15930); MICROMETEO (IPT-310000-2010-22 ) and LE220A11-2 (Junta de Castilla y León).

  10. ISOLDE decay station for decay studies of interest in astrophysics and exotic nuclei

    NASA Astrophysics Data System (ADS)

    Fynbo, Hans; Kirseboom, Oliver S.; Tengblad, Olof

    2017-04-01

    We report on studies of the beta-decays of 31Ar, {}{20,21}Mg, and 16N performed at the ISOLDE decay station (IDS) at CERN. These studies illustrate how beta-decays measured with the IDS can be used to extract information of astrophysical interest, or to study the structure and decay mechanism of exotic nuclei. We discuss the specific implementation of the IDS designed for this type of studies including detector setups and data acquisition.

  11. Application of the string method to the study of critical nuclei in capillary condensation.

    PubMed

    Qiu, Chunyin; Qian, Tiezheng; Ren, Weiqing

    2008-10-21

    We adopt a continuum description for liquid-vapor phase transition in the framework of mean-field theory and use the string method to numerically investigate the critical nuclei for capillary condensation in a slit pore. This numerical approach allows us to determine the critical nuclei corresponding to saddle points of the grand potential function in which the chemical potential is given in the beginning. The string method locates the minimal energy path (MEP), which is the most probable transition pathway connecting two metastable/stable states in configuration space. From the MEP, the saddle point is determined and the corresponding energy barrier also obtained (for grand potential). Moreover, the MEP shows how the new phase (liquid) grows out of the old phase (vapor) along the most probable transition pathway, from the birth of a critical nucleus to its consequent expansion. Our calculations run from partial wetting to complete wetting with a variable strength of attractive wall potential. In the latter case, the string method presents a unified way for computing the critical nuclei, from film formation at solid surface to bulk condensation via liquid bridge. The present application of the string method to the numerical study of capillary condensation shows the great power of this method in evaluating the critical nuclei in various liquid-vapor phase transitions.

  12. Exclusive studies of the GDR in excited nuclei.

    SciTech Connect

    Nanal, V.

    1998-09-07

    The GDR in {sup 164}Er at 62 MeV excitation energy has been studied in coincidence with the evaporation residues, selected using the Argonne fragment mass analyzer (FMA). The {sup 164}Er* has a prolate shape with deformation statistical model fit to the data indicate that similar to the ground state.

  13. Rotational Study of Ambiguous Taxonomic Classified Asteroids

    NASA Astrophysics Data System (ADS)

    Linder, Tyler R.; Sanchez, Rick; Wuerker, Wolfgang; Clayson, Timothy; Giles, Tucker

    2017-01-01

    The Sloan Digital Sky Survey (SDSS) moving object catalog (MOC4) provided the largest ever catalog of asteroid spectrophotometry observations. Carvano et al. (2010), while analyzing MOC4, discovered that individual observations of asteroids which were observed multiple times did not classify into the same photometric-based taxonomic class. A small subset of those asteroids were classified as having both the presence and absence of a 1um silicate absorption feature. If these variations are linked to differences in surface mineralogy, the prevailing assumption that an asteroid’s surface composition is predominantly homogenous would need to be reexamined. Furthermore, our understanding of the evolution of the asteroid belt, as well as the linkage between certain asteroids and meteorite types may need to be modified.This research is an investigation to determine the rotational rates of these taxonomically ambiguous asteroids. Initial questions to be answered:Do these asteroids have unique or nonstandard rotational rates?Is there any evidence in their light curve to suggest an abnormality?Observations were taken using PROMPT6 a 0.41-m telescope apart of the SKYNET network at Cerro Tololo Inter-American Observatory (CTIO). Observations were calibrated and analyzed using Canopus software. Initial results will be presented at AAS.

  14. Nuclear-structure studies of exotic nuclei with MINIBALL

    NASA Astrophysics Data System (ADS)

    Butler, P. A.; Cederkall, J.; Reiter, P.

    2017-04-01

    High-resolution γ-ray spectroscopy has been established at ISOLDE for nuclear-structure and nuclear-reaction studies with reaccelerated radioactive ion beams provided by the REX-ISOLDE facility. The MINIBALL spectrometer comprises 24 six-fold segmented, encapsulated high-purity germanium crystals. It was specially designed for highest γ-ray detection efficiency which is advantageous for low-intensity radioactive ion beams. The MINIBALL array has been used in numerous Coulomb-excitation and transfer-reaction experiments with exotic ion beams of energies up to 3 MeV A–1. The physics case covers a wide range of topics which are addressed with beams ranging from neutron-rich magnesium isotopes up to heavy radium isotopes. In the future the HIE-ISOLDE will allow the in-beam γ-ray spectroscopy program to proceed with higher secondary-beam intensity, higher beam energy and better beam quality.

  15. Preliminary studies of electromagnetic sounding of cometary nuclei

    NASA Technical Reports Server (NTRS)

    Gabriel, A.; Warne, L.; Bednarczyk, S.; Elachi, C.

    1978-01-01

    The internal structure of a comet could be determined with a spacecraft borne electromagnetic sounder. A dielectric profile of the comet could be produced in direct analogy with terrestrial glacier and ice sheet sounding experiments. This profile would allow the detection of a rocky core or ice layers if they exist, just as layers in the ice and the bedrock interface have been clearly observed through the Greenland ice sheet. It would also provide a gross estimate of the amount of dust in the icy region. Models for the response of the nucleus and cometary plasma to electromagnetic sounding are developed and used to derive experimental parameters. A point system design was completed. Preliminary engineering study results indicate that the sounder is well within the bounds of current space technology.

  16. The study of the physics of cometary nuclei

    NASA Technical Reports Server (NTRS)

    Whipple, Fred L.

    1987-01-01

    The numerical calculations of stability for many possible orbits of the double nucleus for P/Holmes showed that the likelihood of such a precollision history was quite high. A number of investigations were made of hypothetical orbits for particles about the asteroid Amphitrite to test for stability. The purpose was to establish more favorable fly-by orbits close to the asteroid for the Galileo missions en-route to Jupiter, reducing the collisional hazards. A statistical study was made of the orbits of long-period comets with small original semi-major axes recently perturbed from the great Opik-Oort Cloud. The results from the space missions to Halley's comet are partially reported in the two papers in the appendices.

  17. Particle-Gamma Coincidence Studies of Uranium Nuclei

    NASA Astrophysics Data System (ADS)

    Hughes, R. O.; Ross, T. J.; Beausang, C. W.; Burke, J. T.; Scielzo, N. D.; Basunia, M. S.; Campbell, C. M.; Casperson, R. J.; Crawford, H. L.; Munson, J.; Phair, L.; Ressler, J. J.; Stars-Liberace Collaboration

    2011-10-01

    The STARS/LIBERACE array at the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory is proving to be an extremely versatile device for probing nuclear structure via (charged) particle- γ coincidence spectroscopy. The technique enables the properties of low- and medium-spin states up to and beyond the neutron separation energy to be probed and give rare insights into the high-level density nuclear continuum well above the pair gap. Recently, 234U, 235U, 236U and 237U were studied via (p,d) and (p,t) reactions on 236U and 238U targets. The exit channel and excitation energy of the residual nucleus are selected by measuring the outgoing charged particle using the STARS silicon telescope array, while coincident gamma rays are detected with the LIBERACE clover array. The subsequent particle spectra show the ensemble of states that were directly populated by the reaction while γ-ray coincidences reveal the decay path from a given level. Results from our recent experiment will be presented. This work was supported by DoE Grant Numbers: DE-FG52-06 NA26206 and DE-FG02-05 ER41379.

  18. Protocols for nuclei isolation and nuclear protein extraction from the resurrection plant Xerophyta viscosa for proteomic studies.

    PubMed

    Abdalla, Kamal Omer; Thomson, Jennifer Ann; Rafudeen, Muhammad Suhail

    2009-01-15

    The plant nucleus is an important subcellular organelle but the isolation of pure and enriched nuclei from plants and subsequent extraction of nuclear proteins for proteomic studies is challenging. Here, we present protocols for nuclei isolation and nuclear protein extraction from the resurrection plant, Xerophyta viscosa, and show optimization and modification of the most critical steps.

  19. Job rotation in nursing: a study of job rotation among nursing personnel from the literature and via a questionnaire.

    PubMed

    Järvi, Maija; Uusitalo, Tarja

    2004-09-01

    To obtain information on job rotation among nursing personnel from the literature and via a questionnaire. A nursing career no longer means a series of steps leading up a hierarchy. It has become more like a process of individual growth, involving improvement of employee expertise and skills. Job rotation in connection with career development in a Finnish hospital is considered essential, and participating in job rotation is one requirement for newly vacant nursing posts. Describing job rotation by means of reference to literature, and studying a survey on attitudes of ophthalmic nurses (n = 84) to job rotation. There has been little theoretical or empirical research on job rotation. In this study, one in three had participated in job rotation that was most often considered a positive experience. Self-development was rated substantially useful, but fewer were interested in participating in various kinds of developmental activities. Employee's motivation is the foundation of successful development activity, e.g. job rotation.

  20. Studies of heteronuclear dipolar interactions between spin-1/2 and quadrupolar nuclei by using REDOR during multiple quantum evolution

    NASA Astrophysics Data System (ADS)

    Pruski, M.; Bailly, A.; Lang, D. P.; Amoureux, J.-P.; Fernandez, C.

    1999-06-01

    A new technique for measurements of dipolar interactions in rotating solids is presented that combines the capabilities of multiple quantum magic angle spinning (MQMAS) with the rotational echo double resonance (REDOR). It employs the dipolar recoupling between spin-1/2 ( I) and quadrupolar ( S) nuclei by applying a series of π pulses to the I spins. In contrast to the previously reported MQ-REDOR method, the recoupling sequence is applied during the triple quantum, rather than single quantum evolution. As the dipolar effect is enhanced by the MQ coherence order, this new technique exhibits improved sensitivity toward weak dipolar interactions.

  1. Studying rotational dynamics with a smartphone—accelerometer versus gyroscope

    NASA Astrophysics Data System (ADS)

    Braskén, Mats; Pörn, Ray

    2017-07-01

    The wide-spread availability of smartphones makes them a valuable addition to the measurement equipment of both the physics classroom and the instructional physics laboratory, encouraging an active interaction between measurements and modeling activities. Two useful sensors, available in most modern smartphones and tablets, are the 3-axis acceleration sensor and the 3-axis gyroscope. We explore the strengths and weaknesses of each type of sensor and use them to study the rotational dynamics of objects rotating about a fixed axis. Care has to be taken when interpreting acceleration sensor data, and in some cases the gyroscope will allow for rotational measurements not easily replicated using the acceleration sensor.

  2. Studies of Low Luminosity Active Galactic Nuclei with Monte Carlo and Magnetohydrodynamic Simulations

    NASA Astrophysics Data System (ADS)

    Hilburn, Guy Louis

    Results from several studies are presented which detail explorations of the physical and spectral properties of low luminosity active galactic nuclei. An initial Sagittarius A* general relativistic magnetohydrodynamic simulation and Monte Carlo radiation transport model suggests accretion rate changes as the dominant flaring method. A similar study on M87 introduces new methods to the Monte Carlo model for increased consistency in highly energetic sources. Again, accretion rate variation seems most appropriate to explain spectral transients. To more closely resolve the methods of particle energization in active galactic nuclei accretion disks, a series of localized shearing box simulations explores the effect of numerical resolution on the development of current sheets. A particular focus on numerically describing converged current sheet formation will provide new methods for consideration of turbulence in accretion disks.

  3. Systematic study on alpha decay in 184-216Bi nuclei

    NASA Astrophysics Data System (ADS)

    Santhosh, K. P.; Priyanka, B.; Unnikrishnan, M. S.

    2013-04-01

    A systematic study on the α-decay half lives of the isotopes of Bi (Z = 83) nuclei in the region 184 ≤ A ≤ 216 has been done using the Coulomb and proximity potential model (CPPM). The computed half lives are compared with the experimental data and they are in good agreement. We have modified the assault frequency and re-determined the half lives and they show a better agreement with the experimental value. The standard deviation of the logarithm of half life with the former assault frequency is found to be 1.323 and with the modified assault frequency, it is found to be 0.223. This reveals that the Coulomb and proximity potential model (CPPM), with the modified deformation dependent assault frequency is more apt for the alpha decay studies. Using our model we could also demonstrate the influence of the 126 neutron shell closure in both parent and daughter nuclei on the alpha decay half lives.

  4. Low-Temperature Nuclear Orientation Studies of Nuclei Far from Stability

    NASA Astrophysics Data System (ADS)

    Brown, Daniel Edward

    1990-01-01

    Available from UMI in association with The British Library. Requires signed TDF. In recent years, Low Temperature Nuclear Orientation (LTNO) has become an important technique in the study of nuclei far from stability. LTNO experiments can yield information about magnetic dipole and electric quadrupole moments and about level schemes and electromagnetic decay properties. The theory of LTNO is reviewed. Often the most interesting nuclei have short halflives (<2 hours) and must be produced "on site" by nuclear reactions before undergoing mass selection and direct implantation into cold equipment. At CERN, a new facility (NICOLE) has recently been set up at the ISOLDE -3 isotope separator and a description of this system is given. One of the major current interests in nuclear physics is to study transitional nuclei which lie between well known regions of spherical and deformed nuclei. The neutron deficient Tellurium and Iodine isotopes are examples of such nuclei. In both cases, the influence of a pi g_{9/2} intruder orbital is expected to be strong at low excitation energies and at A ~ 120. The ^ {120}Te decay scheme has been investigated in detail by LTNO supported by gamma-gamma coincidences and conversion electron spectroscopy. An interpretation of the level scheme using an IBM-2 calculation which allows for mixing between the ground state and a (4p-2h) intruder state is made. The success of this calculation provides strong evidence for the existence of the intruder configuration in ^{120}Te. In addition, the relative electric quadrupole moments of the ground states in ^{120-123}I have been measured. The absence of a measurable quadrupole moment in ^{120}I ^{g} supports the idea that this state is the spherical companion of the coexisting, well deformed pi g_{9/2} isomer. The trend in quadrupole moments also provides strong evidence for the existence of an N = 64 sub shell gap which is needed to explain the corresponding magnetic dipole moments. The light Platinum

  5. Fluxes and spectra of quasimonochromatic annihilation photons for studying E1 giant resonances in nuclei

    SciTech Connect

    Dzhilavyan, L. Z.

    2014-12-15

    The fluxes and spectra of quasimonochromatic photons originating from the in-flight annihilation of positrons interacting with electrons of targets are analyzed in the energy region characteristic of the excitation of E1 giant resonances in nuclei. Targets of small thickness and low atomic number are used. The dependences of the spectra on the energy and angle (and their scatter) for positrons incident to the target, on the collimation angle for photons, and on the target thickness are studied.

  6. Round Robin Study of Rotational Strain Rheometers

    SciTech Connect

    Clifford, M.J.

    2000-02-16

    A round robin of testing was performed to compare the performance of rotational dynamic mechanical spectrometers being used within the nuclear weapons complex. Principals from Sandia National Laboratories/New Mexico; Lockheed Martin Y12 Plant at Oak Ridge, Tennessee; Los Alamos National Laboratory, New Mexico (polycarbonate only); and Honeywell Federal Manufacturing and Technologies (FM and T), Kansas City, MO, performed identical testing of hydrogen blown polysiloxane S5370 and bisphenol-A polycarbonate. Over an oscillation frequency sweep from 0.01 Hz to 15.9 Hz at 135 C, each site produced shear storage modulus values with standard deviations of less than 5%. The data from Sandia, Y12, and Kansas City agreed to within 4%, while the Los Alamos data differed by as much as 13%. Storage modulus values for a frequency sweep of the S5370 at 35 C had standard deviations between 6% and 8%, and site-to-site agreement averaged 3%. The shear loss modulus values had standard deviations of 5%, 7%, and 52% for the sites participating, while the results differed by 12% on average.

  7. Photometric Study of NPA Rotator (5247) Krylov

    NASA Astrophysics Data System (ADS)

    Lee, Hee-Jae; Moon, Hong-Kyu; Kim, Myung-Jin; Kim, Chun-Hwey; Durech, Josef; Choi, Young-Jun; Oh, Young-Seok; Park, Jintae; Roh, Dong-Goo; Yim, Hong-Suh; Cha, Sang-Mok; Lee, Yongseok

    2017-06-01

    We conduct BVRI and R band photometric observations of asteroid (5247) Krylov from January 2016 to April 2016 for 51 nights using the Korea Microlensing Telescope Network (KMTNet). The color indices of (5247) Krylov at the light curve maxima are determined as B - V = 0.841 ± 0.035, V - R = 0.418 ± 0.031, and V - I = 0.871 ± 0.031 where the phase angle is 14.1°. They are acquired after the standardization of BVRI instrumental measurements using the ensemble normalization technique. Based on the color indices, (5247) Krylov is classified as a S-type asteroid. Double periods, that is, a primary period P_{1} = 82.188±0.013 h and a secondary period P_{2} = 67.13±0.20 h are identified from period searches of its R band light curve. The light curve phases with P_{1} and this indicate that it is a typical Non-Principal Axis (NPA) asteroid. We discuss the possible causes of its NPA rotation.

  8. 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.

  9. Differential rotation in rapidly rotating early-type stars. I. Motivations for combined spectroscopic and interferometric studies

    NASA Astrophysics Data System (ADS)

    Zorec, J.; Frémat, Y.; Domiciano de Souza, A.; Delaa, O.; Stee, P.; Mourard, D.; Cidale, L.; Martayan, C.; Georgy, C.; Ekström, S.

    2011-02-01

    Context. Since the external regions of the envelopes of rapidly rotating early-type stars are unstable to convection, a coupling may exist between the convection and the internal rotation. Aims: We explore what can be learned from spectroscopic and interferometric observations about the properties of the rotation law in the external layers of these objects. Methods: Using simple relations between the entropy and specific rotational quantities, some of which are found to be efficient at accounting for the solar differential rotation in the convective region, we derived analytical solutions that represent possible differential rotations in the envelope of early-type stars. A surface latitudinal differential rotation may not only be an external imprint of the inner rotation, but induces changes in the stellar geometry, the gravitational darkening, the aspect of spectral line profiles, and the emitted spectral energy distribution. Results: By studying the equation of the surface of stars with non-conservative rotation laws, we conclude that objects undergo geometrical deformations that are a function of the latitudinal differential rotation able to be scrutinized both spectroscopically and by interferometry. The combination of Fourier analysis of spectral lines with model atmospheres provides independent estimates of the surface latitudinal differential rotation and the inclination angle. Models of stars at different evolutionary stages rotating with internal conservative rotation laws were calculated to show that the Roche approximation can be safely used to account for the gravitational potential. The surface temperature gradient in rapid rotators induce an acceleration to the surface angular velocity. Although a non-zero differential rotation parameter may indicate that the rotation is neither rigid nor shellular underneath the stellar surface, still further information, perhaps non-radial pulsations, is needed to determine its characteristics as a function of depth

  10. Numerical studies of Siberian snakes and spin rotators for RHIC

    SciTech Connect

    Luccio, A.

    1995-04-17

    For the program of polarized protons in RHIC, two Siberian snakes and four spin rotators per ring will be used. The Snakes will produce a complete spin flip. Spin Rotators, in pairs, will rotate the spin from the vertical direction to the horizontal plane at a given insertion, and back to the vertical after the insertion. Snakes, 180{degrees} apart and with their axis of spin precession at 90{degrees} to each other, are an effective means to avoid depolarization of the proton beam in traversing resonances. Classical snakes and rotators are made with magnetic solenoids or with a sequence of magnetic dipoles with fields alternately directed in the radial and vertical direction. Another possibility is to use helical magnets, essentially twisted dipoles, in which the field, transverse the axis of the magnet, continuously rotates as the particles proceed along it. After some comparative studies, the authors decided to adopt for RHIC an elegant solution with four helical magnets both for the snakes and the rotators proposed by Shatunov and Ptitsin. In order to simplify the construction of the magnets and to minimize cost, four identical super conducting helical modules will be used for each device. Snakes will be built with four right-handed helices. Spin rotators with two right-handed and two left-handed helices. The maximum field will be limited to 4 Tesla. While small bore helical undulators have been built for free electron lasers, large super conducting helical magnets have not been built yet. In spite of this difficulty, this choice is dictated by some distinctive advantages of helical over more conventional transverse snakes/rotators: (i) the devices are modular, they can be built with arrangements of identical modules, (ii) the maximum orbit excursion in the magnet is smaller, (iii) orbit excursion is independent from the separation between adjacent magnets, (iv) they allow an easier control of the spin rotation and the orientation of the spin precession axis.

  11. Study of ground and excited state decays in N ≈ Z Ag nuclei

    NASA Astrophysics Data System (ADS)

    Moschner, K.; Blazhev, A.; Warr, N.; Boutachkov, P.; Davies, P.; Wadsworth, R.; Ameil, F.; Baba, H.; Bäck, T.; Dewald, M.; Doornenbal, P.; Faestermann, T.; Gengelbach, A.; Gerl, J.; Gernhäuser, R.; Go, S.; Górska, M.; Grawe, H.; Gregor, E.; Hotaka, H.; Isobe, T.; Jenkins, D. G.; Jolie, J.; Jung, H. S.; Kojouharov, I.; Kurz, N.; Lewitowicz, M.; Lorusso, G.; Merchan, E.; Naqvi, F.; Nishibata, H.; Nishimura, D.; Nishimura, S.; Pietralla, N.; Schaffner, H.; Söderström, P.-A.; Steiger, K.; Sumikama, T.; Taprogge, J.; Thöle, P.; Watanabe, H.; Werner, V.; Xu, Z. Y.; Yagi, A.; Yoshinaga, K.; Zhu, Y.

    2015-05-01

    A decay spectroscopy experiment was performed within the EURICA campaign at RIKEN in 2012. It aimed at the isomer and particle spectroscopy of excited states and ground states in the mass region below the doubly magic 100Sn. The N = Z nuclei 98In, 96Cd and 94Ag were of particular interest for the present study. Preliminary results on the neutron deficient nuclei 93Ag and 94Ag are presented. In 94Ag a more precise value for the half-life of the ground state's superallowed Fermi transition was deduced. In addition the energy spectra of the mentioned decay could be reproduced through precise Geant4 simulations of the used active stopper SIMBA. This will enable us to extract Qβ values from the measured data. The decay of 93Ag is discussed based on the observed implantation-decay correlation events.

  12. Exotic Nuclei

    SciTech Connect

    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.

  13. Mercurated nucleotides: assessment of a new tool to study RNA synthesis and processing in isolated nuclei.

    PubMed Central

    Schäfer, K P

    1977-01-01

    Mercurated pyrimidine nucleotides have been used to study RNA synthesis and processing in isolated nuclei from mouse L cells. 5-mercuridine triphosphate (5-Hg-UTP) or 5-Hg-CTP are accepted as substrates by the purified RNA polymerases (I+III) and (II) from mouse cells, respectively, as well as by the enzymes still bound to the nuclear chromatin. In nuclei, RNA synthesis in the presence of Hg-UTP is reduced to 60-70% of a control. 30-60% of RNA labeled in vitro with (3H)UTP in isolated nuclei is not retained on sulfhydryl sepharose columns. Sucrose gradient analysis reveals a size distribution of the non-bound RNA similar to non-mercurated control RNA. Hg-RNA is found in a single peak from 4-10S. Chase experiments indicate that this RNA is the original transcript. It is argued that Hg-nucleotides may cause premature chain termination. Methylation of RNA in vitro by S-adenosyl methionine ((3H)SAM) is reduced to 75% of controls in the presence of Hg-UTP. Only 6% of the methyl groups appear in Hg-RNA. Polyadenylation is reduced as well. 15% of poly(A) (+)RNA are found in control assays whereas only 1% of Hg-RNA carries a poly(A) end added in vitro. These results limit the use of mercurated nucleotides for studies of nuclear RNA synthesis and processing. PMID:600804

  14. The organization of the pretectal nuclei in the trout: a revision based on experimental holodogical studies.

    PubMed

    Folgueira, Mónica; Anadón, Ramón; Yáñez, Julián

    2008-03-18

    The neuronal tracer DiI was applied to different brain centers of the rainbow trout in order to study the connections of pretectal nuclei. Our results showed that some pretectal nuclei receive a direct projection from the contralateral retina: the parvocellular superficial pretectal nucleus, the central pretectal nucleus, the intermediate pretectal nucleus and the ventral accessory optic nucleus. In turn, the central pretectal, the intermediate pretectal and the ventral accessory optic nuclei, together with the paracommissural nucleus, project to the cerebellum and the torus longitudinalis. The magnocellular superficial pretectal nucleus does not receive retinal projections, but receives ipsilateral projections from the optic tectum and the mesencephalic tegmentum. In turn, it projects to the ipsilateral oculomotor nucleus and lateral nucleus of the valvula. The posterior pretectal nucleus and the parvocellular superficial pretectal nucleus receive afferents from the ipsilateral nucleus isthmi. The posterior pretectal nucleus projects to the inferior hypothalamic lobe. Our results reveal a conspicuous projection from the ipsilateral parvocellular superficial pretectal nucleus to the contralateral one and also to the contralateral posterior prectectal nucleus, not reported in previous experimental studies of teleosts. Pretectal centers appear to integrate visual/optic-related centers mainly with the hypothalamus and the cerebellum. The organization of the trout pretectum was compared with the pretectal organization patterns proposed in various teleosts.

  15. Secondary structure of protamine in sperm nuclei: an infrared spectroscopy study

    PubMed Central

    2011-01-01

    Background Protamines are small basic proteins that condense the DNA in mature spermatozoa. Typical protamines are of simple composition and very arginine-rich, usually in the range of 60-80%. Arginine residues are distributed in a number of stretches separated by neutral amino acids. We have used Fourier transform infrared spectroscopy (FTIR) to gain access for the first time to the secondary structure of protamines in sperm nuclei. This technique is particularly well suited to the study of DNA-bound protamine in whole nuclei since it is not affected by turbidity. Results We show that DNA -bound salmon (salmine) and squid protamines contain α-helix, β-turns and a proportion of other structures not stabilized by intramolecular hydrogen bonding. No β-sheet was observed. In salmine, the α-helix amounted to ~20%, while in squid protamine it reached ~40%. In contrast, the structure not stabilized by intermolecular hydrogen bonding was more abundant in salmine (~40%) than in squid protamine (~20%). Both protamines contained ~40% β-turns. The different helical potential of salmine and squid protamine was confirmed by structure predictions and CD in the presence of trifluoroethanol. Conclusion DNA-bound protamine in sperm nuclei contains large amounts of defined secondary structure stabilized by intramolecular hydrogen bonding. Both salmine and squid protamine contain similar amounts of β-turns, but differ in the proportions of α-helix and non-hydrogen bonded conformations. In spite of the large differences in the proportions of secondary structure motifs between salmon and squid protamines, they appear to be equally efficient in promoting tight hexagonal packing of the DNA molecules in sperm nuclei. PMID:21435240

  16. Systematic study of α decay for odd-A nuclei within a two-potential approach

    NASA Astrophysics Data System (ADS)

    Sun, Xiao-Dong; Duan, Chao; Deng, Jun-Gang; Guo, Ping; Li, Xiao-Hua

    2017-01-01

    α decay is usually associated with both ground and low-lying isomeric states of heavy and superheavy nuclei, and the unpaired nucleon plays a key role in α decay. In this work, we systematically studied the α decay half-lives of odd-A nuclei, including both favored and unfavored α decay within the two-potential approach based on the isospin dependent nuclear potential. The α preformation probabilities are estimated by using an analytic formula taking into account the shell structure and proton-neutron correlation, and the parameters are obtained through the α decay half-lives data. The results indicate that, in general, the α preformation probabilities of even-Z , odd-N nuclei are slightly smaller than the odd-Z , even-N ones. We found that the odd-even staggering effect may play a more important role on spontaneous fission than α decay. The calculated half-lives can well reproduce the experimental data.

  17. Single particle versus collectivity, shapes of exotic nuclei

    NASA Astrophysics Data System (ADS)

    Jungclaus, Andrea

    2016-03-01

    In this article some selected topics of nuclear structure research will be discussed as illustration of the progress reached in this field during the last thirty years. These examples evidence the improvement of our understanding of the atomic nucleus reached on the basis of countless experiments, performed to study both exotic nuclei (nuclei far-off the valley of stability) as well as nuclei under exotic conditions (high excitation energy/temperature or large angular momentum/rotational frequency), using stable and radioactive ion beams. The experimental progress, in parallel to the advancement of modern theoretical descriptions, led us to a much richer view of this fundamental many-body system.

  18. Systematic study of α decay half-lives of doubly odd nuclei within the two-potential approach

    NASA Astrophysics Data System (ADS)

    Sun, Xiao-Dong; Deng, Jun-Gang; Xiang, Dong; Guo, Ping; Li, Xiao-Hua

    2017-04-01

    α decay is a common and important process of natural radioactivity of the heavy and superheavy nuclei. From the α decay of nuclei, we can obtain much more information of nuclei structure. In our previous works [X.-D. Sun et al., Phys. Rev. C 93, 034316 (2016), 10.1103/PhysRevC.93.034316; X.-D. Sun et al., Phys. Rev. C 95, 014319 (2017), 10.1103/PhysRevC.95.014319], we have done systematic study on the α preformation probability of both the even-even and odd-A nuclei within the two-potential approach. The α preformation probabilities will systematically change due to the shell effect, proton-neutron correlation, and so on. This work is the extension of the previous works. In this work, we systematically study the α decay of doubly odd nuclei. We find that for superallowed α decay the α preformation probabilities of doubly odd nuclei are larger than those of odd-A ones in general, and for the heavier nuclei the extra neutrons suppress the proton-neutron correlation resulting in the small α preformation probabilities. The calculated results can well reproduce the experimental half-lives. The half-lives of the α decay chain beginning from nuclide 296119 are also predicted and compared with various empirical formulas.

  19. Multiwavelength Studies of Rotating Radio Transients

    NASA Astrophysics Data System (ADS)

    Miller, Joshua J.

    Seven years ago, a new class of pulsars called the Rotating Radio Transients (RRATs) was discovered with the Parkes radio telescope in Australia (McLaughlin et al., 2006). These neutron stars are characterized by strong radio bursts at repeatable dispersion measures, but not detectable using standard periodicity-search algorithms. We now know of roughly 100 of these objects, discovered in new surveys and re-analysis of archival survey data. They generally have longer periods than those of the normal pulsar population, and several have high magnetic fields, similar to those other neutron star populations like the X-ray bright magnetars. However, some of the RRATs have spin-down properties very similar to those of normal pulsars, making it difficult to determine the cause of their unusual emission and possible evolutionary relationships between them and other classes of neutron stars. We have calculated single-pulse flux densities for eight RRAT sources observed using the Parkes radio telescope. Like normal pulsars, the pulse amplitude distributions are well described by log-normal probability distribution functions, though two show evidence for an additional power-law tail. Spectral indices are calculated for the seven RRATs which were detected at multiple frequencies. These RRATs have a mean spectral index of = -3.2(7), or = -3.1(1) when using mean flux densities derived from fitting log-normal probability distribution functions to the pulse amplitude distributions, suggesting that the RRATs have steeper spectra than normal pulsars. When only considering the three RRATs for which we have a wide range of observing frequencies, however, and become --1.7(1) and --2.0(1), respectively, and are roughly consistent with those measured for normal pulsars. In all cases, these spectral indices exclude magnetar-like flat spectra. For PSR J1819--1458, the RRAT with the highest bursting rate, pulses were detected at 685 and 3029

  20. Solid state nuclear magnetic resonance studies of cross polarization from quadrupolar nuclei

    SciTech Connect

    De Paul, Susan M.

    1997-08-01

    The development of solid-state Nuclear Magnetic Resonance (NMR) has, to a large extent, focused on using spin-1/2 nuclei as probes to investigate molecular structure and dynamics. For such nuclei, the technique of cross polarization is well-established as a method for sensitivity enhancement. However, over two-thirds of the nuclei in the periodic table have a spin-quantum number greater than one-half and are known as quadrupolar nuclei. Such nuclei are fundamental constituents of many inorganic materials including minerals, zeolites, glasses, and gels. It is, therefore, of interest to explore the extent to which polarization can be transferred from quadrupolar nuclei. In this dissertation, solid-state NMR experiments involving cross polarization from quadrupolar nuclei to spin-1/2 nuclei under magic-angle spinning (MAS) conditions are investigated in detail.

  1. Multifunctional magnetic rotator for micro and nanorheological studies

    NASA Astrophysics Data System (ADS)

    Tokarev, Alexander; Aprelev, Alexey; Zakharov, Mikhail N.; Korneva, Guzeliya; Gogotsi, Yury; Kornev, Konstantin G.

    2012-06-01

    We report on the development of a multifunctional magnetic rotator that has been built and used during the last five years by two groups from Clemson and Drexel Universities studying the rheological properties of microdroplets. This magnetic rotator allows one to generate rotating magnetic fields in a broad frequency band, from hertz to tens kilohertz. We illustrate its flexibility and robustness by conducting the rheological studies of simple and polymeric fluids at the nano and microscale. First we reproduce a temperature-dependent viscosity of a synthetic oil used as a viscosity standard. Magnetic rotational spectroscopy with suspended nickel nanorods was used in these studies. As a second example, we converted the magnetic rotator into a pump with precise controlled flow modulation. Using multiwalled carbon nanotubes, we were able to estimate the shear modulus of sickle hemoglobin polymer. We believe that this multifunctional magnetic system will be useful not only for micro and nanorheological studies, but it will find much broader applications requiring remote controlled manipulation of micro and nanoobjects.

  2. Multifunctional magnetic rotator for micro and nanorheological studies

    PubMed Central

    Tokarev, Alexander; Aprelev, Alexey; Zakharov, Mikhail N.; Korneva, Guzeliya; Gogotsi, Yury; Kornev, Konstantin G.

    2012-01-01

    We report on the development of a multifunctional magnetic rotator that has been built and used during the last five years by two groups from Clemson and Drexel Universities studying the rheological properties of microdroplets. This magnetic rotator allows one to generate rotating magnetic fields in a broad frequency band, from hertz to tens kilohertz. We illustrate its flexibility and robustness by conducting the rheological studies of simple and polymeric fluids at the nano and microscale. First we reproduce a temperature-dependent viscosity of a synthetic oil used as a viscosity standard. Magnetic rotational spectroscopy with suspended nickel nanorods was used in these studies. As a second example, we converted the magnetic rotator into a pump with precise controlled flow modulation. Using multiwalled carbon nanotubes, we were able to estimate the shear modulus of sickle hemoglobin polymer. We believe that this multifunctional magnetic system will be useful not only for micro and nanorheological studies, but it will find much broader applications requiring remote controlled manipulation of micro and nanoobjects. PMID:22755665

  3. Piezoelectric Vibration Damping Study for Rotating Composite Fan Blades

    NASA Technical Reports Server (NTRS)

    Min, James B.; Duffy, Kirsten P.; Choi, Benjamin B.; Provenza, Andrew J.; Kray, Nicholas

    2012-01-01

    Resonant vibrations of aircraft engine blades cause blade fatigue problems in engines, which can lead to thicker and aerodynamically lower performing blade designs, increasing engine weight, fuel burn, and maintenance costs. In order to mitigate undesirable blade vibration levels, active piezoelectric vibration control has been investigated, potentially enabling thinner blade designs for higher performing blades and minimizing blade fatigue problems. While the piezoelectric damping idea has been investigated by other researchers over the years, very little study has been done including rotational effects. The present study attempts to fill this void. The particular objectives of this study were: (a) to develop and analyze a multiphysics piezoelectric finite element composite blade model for harmonic forced vibration response analysis coupled with a tuned RLC circuit for rotating engine blade conditions, (b) to validate a numerical model with experimental test data, and (c) to achieve a cost-effective numerical modeling capability which enables simulation of rotating blades within the NASA Glenn Research Center (GRC) Dynamic Spin Rig Facility. A numerical and experimental study for rotating piezoelectric composite subscale fan blades was performed. It was also proved that the proposed numerical method is feasible and effective when applied to the rotating blade base excitation model. The experimental test and multiphysics finite element modeling technique described in this paper show that piezoelectric vibration damping can significantly reduce vibrations of aircraft engine composite fan blades.

  4. Study of Collectivity in n-rich A=80 Nuclei using Radioactive Ion Beams

    NASA Astrophysics Data System (ADS)

    Padilla, E.; Galindo-Uribarri, A.; Baktash, C.; Fuentes, B.; Gross, C.; Mueller, P.; Radford, D. C.; Stracener, D.; Yu, C.-H.; Bijker, R.; Castanos, O.; Batchelder, J.; Hartley, D. J.

    2002-04-01

    We report on recent experiments performed at the HRIBF of Oak Ridge National Laboratory (ORNL) aimed to study neutron-rich nuclei in the A 80 mass region. First time use of Radioactive Ion Beams (RIBs) (78,80)Ge complemented with stable beam information allowed a systematic study of B(E2)-values that characterize the n-rich even-even Ge and Se isotopes. A comparison of the experimental results with IBA2 calculations will be presented. *Supported by US-DOE under the contract DE-AC05-00AOR22725.

  5. Study of nuclear structure of odd mass 119-127I nuclei in a phenomenological approach

    NASA Astrophysics Data System (ADS)

    Singh, Dhanvir; Gupta, Anuradha; Kumar, Amit; Sharma, Chetan; Singh, Suram; Bharti, Arun; Khosa, S. K.; Bhat, G. H.; Sheikh, J. A.

    2016-08-01

    By using the phenomenological approach of Projected Shell Model (PSM), the positive and negative-parity band structures of odd mass neutron-rich 119-127I nuclei have been studied with the deformed single-particle states generated by the standard Nilsson potential. For these isotopes, the band structures have been analyzed in terms of quasi-particles configurations. The phenomenon of backbending in moment of inertia is also studied in the present work. Besides this, the reduced transition probabilities, i.e. B (E 2) and B (M 1), are obtained from the PSM wavefunction for the first time for yrast bands of these isotopes.

  6. The ratio method: A new tool to study one-neutron halo nuclei

    DOE PAGES

    Capel, Pierre; Johnson, R. C.; Nunes, F. M.

    2013-10-02

    Recently a new observable to study halo nuclei was introduced, based on the ratio between breakup and elastic angular cross sections. This new observable is shown by the analysis of specific reactions to be independent of the reaction mechanism and to provide nuclear-structure information of the projectile. Here we explore the details of this ratio method, including the sensitivity to binding energy and angular momentum of the projectile. We also study the reliability of the method with breakup energy. Lastly, we provide guidelines and specific examples for experimentalists who wish to apply this method.

  7. Antisymmetrized molecular dynamics studies for exotic clustering phenomena in neutron-rich nuclei

    NASA Astrophysics Data System (ADS)

    Kimura, M.; Suhara, T.; Kanada-En'yo, Y.

    2016-12-01

    We present a review of recent works on clustering phenomena in unstable nuclei studied by antisymmetrized molecular dynamics (AMD). The AMD studies in these decades have uncovered novel types of clustering phenomena brought about by the excess neutrons. Among them, this review focuses on the molecule-like structure of unstable nuclei. One of the earliest discussions on the clustering in unstable nuclei was made for neutron-rich Be and B isotopes. AMD calculations predicted that the ground state clustering is enhanced or reduced depending on the number of excess neutrons. Today, the experiments are confirming this prediction as the change of the proton radii. Behind this enhancement and reduction of the clustering, there are underlying shell effects called molecular and atomic orbits. These orbits form covalent and ionic bonding of the clusters analogous to the atomic molecules. It was found that this "molecular-orbit picture" reasonably explains the low-lying spectra of Be isotopes. The molecular-orbit picture is extended to other systems having parity asymmetric cluster cores and to the three cluster systems. O and Ne isotopes are the candidates of the former, while the 3 α linear chains in C isotopes are the latter. For both subjects, many intensive studies are now in progress. We also pay a special attention to the observables which are the fingerprint of the clustering. In particular, we focus on the monopole and dipole transitions which are recently regarded as good probe for the clustering. We discuss how they have and will reveal the exotic clustering.

  8. Experimental study of upper sd shell nuclei and evolution of sd-fp shell gap

    SciTech Connect

    Sarkar, M. Saha

    2012-06-27

    The intruder orbitals from the fp shell play important role in the structure of nuclei around the line of stability in the upper sd shell. Experimentally we have studied {sup 35}Cl, {sup 30}P, {sup 36}Cl, {sup 37}Ar and {sup 34}Cl in this mass region using the INGA setup. Large basis cross-shell shell model calculations have indicated the need for change of the sd-fp energy gap for reliable reproduction of negative parity and high spin positive parity states. Indication of population of states of large deformation has been found in our data. Theoretical interpretation of these states has been discussed.

  9. Selective transport of cationized fluorescent topoisomerase into nuclei of live cells for DNA damage studies.

    PubMed

    Minchew, Candace L; Didenko, Vladimir V

    2014-01-01

    The targeted delivery of fluorescently labeled, DNA-modifying proteins into cellular nuclei permits investigation of DNA damage and chromatin function in living cells. Commercially available protein delivery vectors cannot provide selective intranuclear transportation and primarily unload their cargo in the cytoplasm. Here we describe a simple approach for specific intranuclear transportation of vaccinia topoisomerase protein based on its cationization. The delivered protein can be observed and monitored by fluorescence microscopy. The technique is cost-efficient and time-saving. It can be useful in live cell studies.

  10. Experimental study on flow past a rotationally oscillating cylinder

    NASA Astrophysics Data System (ADS)

    Gao, Yang-yang; Yin, Chang-shan; Yang, Kang; Zhao, Xi-zeng; Tan, Soon Keat

    2017-08-01

    A series of experiments was carried out to study the flow behaviour behind a rotationally oscillating cylinder at a low Reynolds number (Re=300) placed in a recirculation water channel. A stepper motor was used to rotate the cylinder clockwise- and- counterclockwise about its longitudinal axis at selected frequencies. The particle image velocimetry (PIV) technique was used to capture the flow field behind a rotationally oscillating cylinder. Instantaneous and timeaveraged flow fields such as the vorticity contours, streamline topologies and velocity distributions were analyzed. The effects of four rotation angle and frequency ratios F r ( F r= f n/ f v, the ratio of the forcing frequency f n to the natural vortex shedding frequency f v) on the wake in the lee of a rotationally oscillating cylinder were also examined. The significant wake modification was observed when the cylinder undergoes clockwise-and-counterclockwise motion with amplitude of π, especially in the range of 0.6≤ F r≤1.0.

  11. The Prototype Dipeptide Gly-Gly a Rotational Study

    NASA Astrophysics Data System (ADS)

    Varela, M.; Cabezas, C.; Mata, S.; Alonso, J. L.

    2013-06-01

    The simplest dipeptide Gly-Gly has been examined for the first time in the gas phase by laser ablation molecular beam Fourier transform microwave (LA-MB-FTMW) spectroscopy. The nuclear quadrupole hyperfine structure of two ^{14}N nuclei has been totally resolved allowing the conclusive identification of three conformers in the supersonic expansion. Intramolecular hydrogen bonding interactions have been analyzed on the bases of the structure of the observed conformers. Present results indicate that it is possible to face the study larger peptides using LA-MB-FTMW spectroscopy.

  12. The Study of Leukocyte Functions in a Rotating Wall Vessel

    NASA Technical Reports Server (NTRS)

    Trial, JoAnn

    1998-01-01

    The objective of this study was to investigate the behavior of leukocytes under free-fall conditions in a rotating wall vessel. In such a vessel, the tendency of a cell to fall in response to gravity is opposed by the rotation of the vessel and the culture medium within, keeping the cells in suspension without fluid shear. Previous reports indicated that such functions as lymphocyte migration through collagen matrix or monocyte cytokine secretion are altered under these conditions, and these changes correlate with similar functional defects of cultured cells seen during spaceflight.

  13. Nuclear magnetic resonance studies of quadrupolar nuclei and dipolar field effects

    SciTech Connect

    Urban, Jeffry Todd

    2004-01-01

    Experimental and theoretical research conducted in two areas in the field of nuclear magnetic resonance (NMR) spectroscopy is presented: (1) studies of the coherent quantum-mechanical control of the angular momentum dynamics of quadrupolar (spin I > 1/2) nuclei and its application to the determination of molecular structure; and (2) applications of the long-range nuclear dipolar field to novel NMR detection methodologies.The dissertation is organized into six chapters. The first two chapters and associated appendices are intended to be pedagogical and include an introduction to the quantum mechanical theory of pulsed NMR spectroscopy and the time dependent theory of quantum mechanics. The third chapter describes investigations of the solid-state multiple-quantum magic angle spinning (MQMAS) NMR experiment applied to I = 5/2 quadrupolar nuclei. This work reports the use of rotary resonance-matched radiofrequency irradiation for sensitivity enhancement of the I = 5/2 MQMAS experiment. These experiments exhibited certain selective line narrowing effects which were investigated theoretically.The fourth chapter extends the discussion of multiple quantum spectroscopy of quadrupolar nuclei to a mostly theoretical study of the feasibility of enhancing the resolution of nitrogen-14 NMR of large biomolecules in solution via double-quantum spectroscopy. The fifth chapter continues to extend the principles of multiple quantum NMR spectroscopy of quadrupolar nuclei to make analogies between experiments in NMR/nuclear quadrupolar resonance (NQR) and experiments in atomic/molecular optics (AMO). These analogies are made through the Hamiltonian and density operator formalism of angular momentum dynamics in the presence of electric and magnetic fields.The sixth chapter investigates the use of the macroscopic nuclear dipolar field to encode the NMR spectrum of an analyte nucleus indirectly in the magnetization of a sensor nucleus. This technique could potentially serve as an

  14. Systematic study on the competition between α-decay and spontaneous fission of superheavy nuclei

    NASA Astrophysics Data System (ADS)

    Zhang, Y. L.; Wang, Y. Z.

    2017-10-01

    The competition between α-decay and spontaneous fission (SF) of Z = 112 isotopes are studied. The α-decay half-lives are estimated by the generalized liquid-drop model (GLDM) and several sets of analytic formulas. These formulas include the Royer formula, Viola-Seaborg semiempirical (VSS) formula and universal decay law (UDL). For the SF, its half-lives are calculated by using the Xu, Ren, Karpov and Santhosh formulas. It is shown that the predicted α-decay half-lives by different approaches are more or less identical. However, the SF half-lives are highly sensitive to models. To test the accuracies of different SF formulas, the half-lives of 56 even-even heavy nuclei are calculated by these formulas. By comparing with the experimental data, it is found that the Xu formula is the most accurate one to reproduce the experimental SF half-lives. This allows us to make a systematic prediction on the competition between α-decay and SF of even-even superheavy nuclei (SHN) with Z = 104- 120 by using the Xu formula and the above mentioned models on α-decay. The calculations suggest that 258,260104, 268-276110, 270-280112, 272-286114, 274-294116, 284-302118 and 292-308120 have smaller α-decay half-lives than those of SF. Thus these nuclei can be synthesized and identified via α-decay in the laboratory. In addition, it is observed that N = 162, 178, 184 and 196 may be the submagic or magic numbers. Finally, an extensive study on the possible α-decay chains for Z = 120 isotopes is performed. It is predicted that six sequential α-decay chains can be observed from 292-296120, four α-decay chains from 298120, three α-decay chains from 300,302120, two α-decay chains from 304,306120, and only one α-decay chain from 308120. These nuclei are the most likely candidates to be synthesized experimentally via α-decay in the near future.

  15. Nuclei at High Angular Momentum

    SciTech Connect

    Diamond, R. M.; Stephens, F. S.

    1980-12-01

    It appears that most nuclei show a compromise between purely collective and purely non-collective behavior at very high spins.non~collective behavior in nuclei has been seen only as high as 36 or 37{bar h}, at which point a more collective structure seems to develop. The concepts underlying the study of high angular momentum states are discussed. The factors that limit angular momentum in nuclei are considered. The currently emerging state of physics of very high spin states is reviewed. The detailed calculations currently made for high spin states are described, focusing not on the calculations themselves, but on the physical input to them and results that come out. Production of high-spin states using heavy-ion reactions is reviewed. Studies of {gamma}-rays de-exciting the evaporation residues from heavy-ion reactions are covered. Two types of {gamma} rays occur: those that cool the nucleus to or toward the yrast line, called "statistical," and those that are more or less parallel to the yrast line and remove the angular momentum, called "yrast~like." Collective rotation, in simplest form the motion of a deformed nucleus around an axis perpendicular to its symmetry axis, is also covered.

  16. Study of RNA Polymerase II Clustering inside Live-Cell Nuclei Using Bayesian Nanoscopy.

    PubMed

    Chen, Xuanze; Wei, Mian; Zheng, M Mocarlo; Zhao, Jiaxi; Hao, Huiwen; Chang, Lei; Xi, Peng; Sun, Yujie

    2016-02-23

    Nanoscale spatiotemporal clustering of RNA polymerase II (Pol II) plays an important role in transcription regulation. However, dynamics of individual Pol II clusters in live-cell nuclei has not been measured directly, prohibiting in-depth understanding of their working mechanisms. In this work, we studied the dynamics of Pol II clustering using Bayesian nanoscopy in live mammalian cell nuclei. With 50 nm spatial resolution and 4 s temporal resolution, Bayesian nanoscopy allows direct observation of the assembly and disassembly dynamics of individual Pol II clusters. The results not only provide quantifications of Pol II clusters but also shed light on the understanding of cluster formation and regulation. Our study suggests that transcription factories form on-demand and recruit Pol II molecules in their pre-elongation phase. The assembly and disassembly of individual Pol II clusters take place asynchronously. Overall, the methods developed herein are also applicable to studying a wide realm of real-time nanometer-scale nuclear processes in live cells.

  17. Single Particle Orientation and Rotational Tracking (SPORT) in biopysical studies

    SciTech Connect

    Gu, Yan; Ha, Ji Won; Augspurger, Ashley E.; Chen, Kuangcai; Zhu, Shaobin; Fang, Ning

    2013-08-02

    The single particle orientation and rotational tracking (SPORT) techniques have seen rapid development in the past 5 years. Recent technical advances have greatly expanded the applicability of SPORT in biophysical studies. In this feature article, we survey the current development of SPORT and discuss its potential applications in biophysics, including cellular membrane processes and intracellular transport.

  18. Sports Medicine. Clinical Rotation. Instructor's Packet and Student Study Packet.

    ERIC Educational Resources Information Center

    Texas Univ., Austin. Extension Instruction and Materials Center.

    The materials in this packet are for a course designed to provide individualized classroom study for a specific area of clinical rotation--sports medicine. The instructor's manual describes the learning objectives together with a list of reference materials that should be provided for completion of the student worksheets, and lists suggested…

  19. Sports Medicine. Clinical Rotation. Instructor's Packet and Student Study Packet.

    ERIC Educational Resources Information Center

    Texas Univ., Austin. Extension Instruction and Materials Center.

    The materials in this packet are for a course designed to provide individualized classroom study for a specific area of clinical rotation--sports medicine. The instructor's manual describes the learning objectives together with a list of reference materials that should be provided for completion of the student worksheets, and lists suggested…

  20. Beyond-mean-field study of elastic and inelastic electron scattering off nuclei

    NASA Astrophysics Data System (ADS)

    Yao, J. M.; Bender, M.; Heenen, P.-H.

    2015-02-01

    Background: Electron scattering provides a powerful tool to determine charge distributions and transition densities of nuclei. This tool will soon be available for short-lived neutron-rich nuclei. Purpose: Beyond-mean-field methods have been successfully applied to the study of excitation spectra of nuclei in the whole nuclear chart. These methods permit determination of energies and transition probabilities starting from an effective in-medium nucleon-nucleon interaction but without other phenomenological ingredients. Such a method has recently been extended to calculate the charge density of nuclei deformed at the mean-field level of approximation [J. M. Yao et al., Phys. Rev. C 86, 014310 (2012), 10.1103/PhysRevC.86.014310]. The aim of this work is to further extend the method to the determination of transition densities between low-lying excited states. Method: The starting point of our method is a set of Hartree-Fock-Bogoliubov wave functions generated with a constraint on the axial quadrupole moment and using a Skyrme energy density functional. Correlations beyond the mean field are introduced by projecting mean-field wave functions on angular momentum and particle number and by mixing the symmetry-restored wave functions. Results: We give in this paper detailed formulas derived for the calculation of densities and form factors. These formulas are rather easy to obtain when both initial and final states are 0+ states but are far from being trivial when one of the states has a finite J value. Illustrative applications to 24Mg and to the even-mass Ni-6858 have permitted an analysis of the main features of our method, in particular the effect of deformation on densities and form factors. An illustrative calculation of both elastic and inelastic scattering form factors is presented. Conclusions: We present a very general framework to calculate densities of and transition densities between low-lying states that can be applied to any nucleus. Achieving better

  1. Comorbidities in rotator cuff disease: a case-control study.

    PubMed

    Titchener, Andrew G; White, Jonathan J E; Hinchliffe, Sally R; Tambe, Amol A; Hubbard, Richard B; Clark, David I

    2014-09-01

    Rotator cuff disease is a common condition in the general population, but relatively little is known about its associated risk factors. We have undertaken a large case-control study using The Health Improvement Network database to assess and to quantify the relative contributions of some constitutional and environmental risk factors for rotator cuff disease in the community. Our data set included 5000 patients with rotator cuff disease who were individually matched with a single control by age, sex, and general practice (primary care practice). The median age at diagnosis was 55 years (interquartile range, 44-65 years). Multivariate analysis showed that the risk factors associated with rotator cuff disease were Achilles tendinitis (odds ratio [OR] = 1.78), trigger finger (OR = 1.99), lateral epicondylitis (OR = 1.71), and carpal tunnel syndrome (OR = 1.55). Oral corticosteroid therapy (OR = 2.03), oral antidiabetic use (OR = 1.66), insulin use (OR = 1.77), and "overweight" body mass index of 25.1 to 30 (OR = 1.15) were also significantly associated. Current or previous smoking history, body mass index of greater than 30, any alcohol intake, medial epicondylitis, de Quervain syndrome, cubital tunnel syndrome, and rheumatoid arthritis were not found to be associated with rotator cuff disease. We have identified a number of comorbidities and risk factors for rotator cuff disease. These include lateral epicondylitis, carpal tunnel syndrome, trigger finger, Achilles tendinitis, oral corticosteroid use, and diabetes mellitus. The findings should alert the clinician to comorbid pathologic processes and guide future research into the etiology of this condition. Copyright © 2014 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.

  2. Changes in the structure of nuclei between the magic neutron numbers 50 and 82 as indicated by a rotating-cluster analysis of the energy values of the first 2j excited states of isotopes of cadmium

    SciTech Connect

    Pauling, L.

    1981-09-01

    Values of R, the radius of rotation of the rotating cluster, are calculated from the observed values of the energy of the lowest 2/sup +/ states of the even isotopes of Cd, Sn, and Te with the assumption that the cluster is ..cap alpha.., pb, and ..cap alpha.., respectively. R shows a maximum at approx. N = 58, a minimum at approx. N = 62, and a second maximum at approx. N = 70. The increase to the first maximum is interpreted as resulting from the overcrowding of spherons (alphas and tritons) in the mantle (outer layer) of the nuclei, causing the cluster to change from rotating in the mantle to skimming over its surface; the decrease to the minimum results from the addition of three dineutrons to the core, expanding the mantle and permitting the rotating cluster to begin to drop back into it; and the increase to the second maximum results from the overcrowding of the larger mantle surrounding the core containing the semimagic number 14 of neutrons rather than the magic numbers 8 for N = 50. The decrease after the second maximum results from the further increase in the number of core neutrons to 20, corresponding to the magic number 82. Some additional evidence for the change to an intermediate structure between N = 50 and N = 82 is also discussed.

  3. Rotating field collector subsystem phase 1 study and evaluation

    NASA Astrophysics Data System (ADS)

    Jones, D.; Eibling, J. A.

    1982-10-01

    The rotating field collector system is an alternative concept in which all heliostats are mounted on a single large platform which rotates around a tower to track the azumuthal angle of the Sun. Each heliostat is mounted to the platform with appropriate pivots, linkage, and controls to provide the additional positioning required to properly direct the solar radiation onto the receiver. The results are presented of the first phase of a study to investigate the technical and economic merits of a particular type of rotating field collector subsystem. The large pie-shaped platform would revolve over an array of support pedestals by means of a roller at the top of each pedestal. Several heliostats were built to demonstrate their construction features, and the operation of both flat and amphitheater rotating fields was studied. Work included an analysis of the concepts, development of modifications and additions to make the system comply with design criteria, and cost estimates to be used for comparison with other heliostat subsystems. Because of considerably high cost estimates, the focus of a large part of the study was directed toward developing lower cost designs of major components.

  4. Experimental Study of the Flow in a Rotating CVD Reactor

    NASA Astrophysics Data System (ADS)

    Wong, Sun; Meng, Jiandong; Jaluria, Yogesh

    2013-11-01

    An experimental model is developed to study the rotating, vertical, impinging chemical vapor deposition reactor. Deposition occurs only when the system has enough thermal energy. Therefore, understanding the fluid flow and thermal characteristics of the system would provide a good basis to model the thin film deposition process. The growth rate and the uniformity of the film are the two most important factors in the CVD process and these depend strongly on the flow and the thermal transport within the system. Operating parameters, such as inflow velocity, susceptor temperature and rotational speed, are used to create different design simulations. Fluid velocities and temperature distributions are recorded to obtain the effects of different operating parameters. Velocities are recorded by using a rotameter and a hot wire anemometer. The temperatures are recorded by using thermocouples and an infrared thermometer. The effects of buoyancy and rotation are examined. The expermental study is also coupled with a numerical study for validation of the numerical model and to expand the domain. Comparisons between the two models are presented, indicating fair agreement. The numerical model also includes simulation of Gallium Nitride (GaN) thin film deposition. This simulation thus includes mass transport and gas kinetics, along with the flow and heat transfer within the system. A three dimensional simulation is needed due to the rotation of the susceptor. The results obtained as well as the underlying fluid flow phenomena are discussed.

  5. Spectroscopy of few-particle nuclei around magic {sup 132}Sn from fission product {gamma}-ray studies.

    SciTech Connect

    Zhang, C. T.

    1998-07-29

    We are studying the yrast structure of very neutron-rich nuclei around doubly magic {sup 132}Sn by analyzing fission product {gamma}-ray data from a {sup 248}Cm source at Eurogam II. Yrast cascades in several few-valence-particle nuclei have been identified through {gamma}{gamma} cross coincidences with their complementary fission partners. Results for two-valence-particle nuclei {sup 132}Sb, {sup 134}Te, {sup 134}Sb and {sup 134}Sn provide empirical nucleon-nucleon interactions which, combined with single-particle energies already known in the one-particle nuclei, are essential for shell-model analysis in this region. Findings for the N = 82 nuclei {sup 134}Te and {sup 135}I have now been extended to the four-proton nucleus {sup 136}Xe. Results for the two-neutron nucleus {sup 134}Sn and the N = 83 isotones {sup 134}Sb, {sup 135}Te and {sup 135}I open up the spectroscopy of nuclei in the northeast quadrant above {sup 132}Sn.

  6. Numerical Study of Rotating Turbulence with External Forcing

    NASA Technical Reports Server (NTRS)

    Yeung, P. K.; Zhou, Ye

    1998-01-01

    Direct numerical simulation at 256(exp 3) resolution have been carried out to study the response of isotropic turbulence to the concurrent effects of solid-body rotation and numerical forcing at the large scales. Because energy transfer to the smaller scales is weakened by rotation, energy input from forcing gradually builds up at the large scales, causing the overall kinetic energy to increase. At intermediate wavenumbers the energy spectrum undergoes a transition from a limited k(exp -5/3) inertial range to k(exp -2) scaling recently predicted in the literature. Although the Reynolds stress tensor remains approximately isotropic and three-components, evidence for anisotropy and quasi- two-dimensionality in length scales and spectra in different velocity components and directions is strong. The small scales are found to deviate from local isotropy, primarily as a result of anisotropic transfer to the high wavenumbers. To understand the spectral dynamics of this flow we study the detailed behavior of nonlinear triadic interactions in wavenumber space. Spectral transfer in the velocity component parallel to the axis of rotation is qualitatively similar to that in non-rotating turbulence; however the perpendicular component is characterized by a greatly suppressed energy cascade at high wavenumber and a local reverse transfer at the largest scales. The broader implications of this work are briefly addressed.

  7. Laboratory study of forced rotating shallow water turbulence

    NASA Astrophysics Data System (ADS)

    Espa, Stefania; Di Nitto, Gabriella; Cenedese, Antonio

    2011-12-01

    During the last three decades several authors have studied the appearance of multiple zonal jets in planetary atmospheres and in the Earths oceans. The appearance of zonal jets has been recovered in numerical simulations (Yoden & Yamada, 1993), laboratory experiments (Afanasyev & Wells, 2005; Espa et al., 2008, 2010) and in field measurements of the atmosphere of giant planets (Galperin et al., 2001). Recent studies have revealed the presence of zonation also in the Earths oceans, in fact zonal jets have been found in the outputs of Oceanic General Circulation Models-GCMs (Nakano & Hasumi, 2005) and from the analysis of satellite altimetry observations (Maximenko et al., 2005). In previous works (Espa et al., 2008, 2010) we have investigated the impact of the variation of the rotation rate and of the fluid depth on jets organization in decaying and forced regimes. In this work we show results from experiments performed in a bigger domain in which the fluid is forced continuously. The experimental set-up consists of a rotating tank (1m in diameter) where the initial distribution of vorticity has been generated via the Lorentz force in an electromagnetic cell. The latitudinal variation of the Coriolis parameter has been simulated by the parabolic profile assumed by the free surface of the rotating fluid. Flow measurements have been performed using an image analysis technique. Experiments have been performed changing the tank rotation rate and the fluid thickness. We have investigated the flow in terms of zonal and radial flow pattern, flow variability and jet scales.

  8. Studies of nuclei using radioactive beams. Progress report, May 1988--July 1989

    SciTech Connect

    Piercey, R.B.

    1989-07-01

    The 12 month period from May 1988 to July 1989 represents the first full year of our 18 month pilot program in nuclear structure research. In this period, research was initiated to develop a capability for radioactive secondary beams at Argonne National Laboratory using the Atlas and the new Fragment Mass Analyzer (FMA), which is currently under construction. Two major new detector facilities are currently in the final stages of design and testing. The Large-Area, Scintillator Telescope (LAST) detector is fully operational and will be shipped to Argonne National Laboratory in August for fit-tests and in-beam calibrations. The first segments of a new sixteen-segment neutron multiplicity detector have been built and tested. The remaining segments are currently being constructed. Research was continued in the areas of (1) Coulomb excitation studies of rare earth and actinide nuclei; (2) In-beam, gamma-ray spectroscopy of nuclei in the mass 100 region, and (3) Advanced detector design. Several journal articles and abstracts were published or submitted for publication in the reporting period, and others are currently in preparation. Three graduate students participated in the program, one from the University of Florida and two from the Royal Institute of Technology, Stockholm, Sweden.

  9. Studies of nuclei using radioactive beams. [Space Astronomy Lab. , Univ. of Florida, Gainesville, Florida

    SciTech Connect

    Piercey, R.B.

    1989-07-01

    The 12 month period from May 1988 to July 1989 represents the first full year of our 18 month pilot program in nuclear structure research. In this period, research was initiated to develop a capability for radioactive secondary beams at Argonne National Laboratory using the Atlas and the new Fragment Mass Analyzer (FMA), which is currently under construction. Two major new detector facilities are currently in the final stages of design and testing. The Large-Area, Scintillator Telescope (LAST) detector is fully operational and will be shipped to Argonne National Laboratory in August for fit-tests and in-beam calibrations. The first segments of a new sixteen-segment neutron multiplicity detector have been built and tested. The remaining segments are currently being constructed. Research was continued in the areas of (1) Coulomb excitation studies of rare earth and actinide nuclei; (2) In-beam, gamma-ray spectroscopy of nuclei in the mass 100 region, and (3) Advanced detector design. Several journal articles and abstracts were published or submitted for publication in the reporting period, and others are currently in preparation. Three graduate students participated in the program, one from the University of Florida and two from the Royal Institute of Technology, Stockholm, Sweden.

  10. Dust-related ice nuclei profiles from polarization lidar: methodology and case studies

    NASA Astrophysics Data System (ADS)

    Mamouri, R. E.; Ansmann, A.

    2014-10-01

    A lidar technique is presented that permits the estimation of ice nuclei concentrations of mineral dust from polarization lidar measurements. The method is applied to lidar observations of the spaceborne lidar CALIOP (Cloud Aerosol Lidar with Orthogonal Polarization) during two overpasses of the EARLINET (European Aerosol Research Lidar Network) lidar site at the Cyprus University of Technology (CUT), Limassol (34.7° N, 33° E), Cyprus. The good agreement between the CALIOP and CUT lidar observations regarding the retrieval of the aerosol particle concentration for particles larger than 280 nm in radius, APC280, and the ice nuclei concentrations, INC, corroborates the potential of CALIOP to provide 3-D global dust-related INC data sets. The method makes use of the polarization lidar technique for the separation of dust and non-dust aerosol components. The profile of dust extinction coefficient is converted to APC280 and, in a second step, to INC by means of an APC-INC relationship from the literature. The observed close relationship between dust extinction at 500 nm and APC280 is the key to a successful INC retrieval. The correlation between dust extinction coefficient and APC280 is studied by means of AERONET sun/sky photometer at Morocco, Cape Verde, Barbados, and Cyprus, during situations dominated by desert dust outbreaks.

  11. X-ray scattering study of actin polymerization nuclei assembled by tandem W domains

    SciTech Connect

    Rebowski, Grzegorz; Boczkowska, Malgorzata; Hayes, David B.; Guo, Liang; Irving, Thomas C.; Dominguez, Roberto

    2008-08-27

    The initiation of actin polymerization in cells requires actin filament nucleators. With the exception of formins, known filament nucleators use the Wiskott-Aldrich syndrome protein (WASP) homology 2 (WH2 or W) domain for interaction with actin. A common architecture, found in Spire, Cobl, VopL, and VopF, consists of tandem W domains that tie together three to four actin monomers to form a polymerization nucleus. Uncontrollable polymerization has prevented the structural investigation of such nuclei. We have engineered stable nuclei consisting of an actin dimer and a trimer stabilized by tandem W domain hybrid constructs and studied their structures in solution by x-ray scattering. We show that Spire-like tandem W domains stabilize a polymerization nucleus by lining up actin subunits along the long-pitch helix of the actin filament. Intersubunit contacts in the polymerization nucleus, thought to involve the DNase I-binding loop of actin, coexist with the binding of the W domain in the cleft between actin subdomains 1 and 3. The successful stabilization of filament-like multiactin assemblies opens the way to the crystallographic investigation of intersubunit contacts in the actin filament.

  12. Validation of the western ontario rotator cuff index in patients with arthroscopic rotator cuff repair: A study protocol

    PubMed Central

    2011-01-01

    Background Arthroscopic rotator cuff repair is described as being a successful procedure. These results are often derived from clinical general shoulder examinations, which are then classified as 'excellent', 'good', 'fair' or 'poor'. However, the cut-off points for these classifications vary and sometimes modified scores are used. Arthroscopic rotator cuff repair is performed to improve quality of life. Therefore, disease specific health-related quality of life patient-administered questionnaires are needed. The WORC is a quality of life questionnaire designed for patients with disorders of the rotator cuff. The score is validated for rotator cuff disease, but not for rotator cuff repair specifically. The aim of this study is to investigate reliability, validity and responsiveness of WORC in patients undergoing arthroscopic rotator cuff repair. Methods/Design An approved translation of the WORC into Dutch is used. In this prospective study three groups of patients are used: 1. Arthroscopic rotator cuff repair; 2. Disorders of the rotator cuff without rupture; 3. Shoulder instability. The WORC, SF-36 and the Constant Score are obtained twice before therapy is started to measure reliability and validity. Responsiveness is tested by obtaining the same tests after therapy. PMID:21453470

  13. Isomeric Decay Studies in Neutron-Rich N ≈ 126 Nuclei

    NASA Astrophysics Data System (ADS)

    Steer, S. J.; Podolyák, Zs.; Pietri, S.; Górska, M.; Farrelly, G. F.; Regan, P. H.; Rudolph, D.; Garnsworthy, A. B.; Hoischen, R.; Gerl, J.; Wollersheim, H. J.; Grawe, H.; Maier, K. H.; Becker, F.; Bednarczyk, P.; Cáceres, L.; Doornenbal, P.; Geissel, H.; GrȨBOSZ, J.; Kelic, A.; Kojouharov, I.; Kurz, N.; Montes, F.; Prokopowicz, W.; Saito, T.; Schaffner, H.; Tashenov, S.; Heinz, A.; Kurtukian-Nieto, T.; Benzoni, G.; Pfützner, M.; Jungclaus, A.; Balabanski, D. L.; Brandau, C.; Brown, A.; Bruce, A. M.; Catford, W. N.; Cullen, I. J.; Dombrádi, Zs.; Estevez, M. E.; Gelletly, W.; Ilie, G.; Jolie, J.; Jones, G. A.; Kmiecik, M.; Kondev, F. G.; Krücken, R.; Lalkovski, S.; Liu, Z.; Maj, A.; Myalski, S.; Schwertel, S.; Shizuma, T.; Walker, P. M.; Werner-Malento, E.; Wieland, O.

    Heavy neutron-rich nuclei were populated via relativistic energy fragmentation of a E/A = 1 GeV 208Pb beam. The nuclei of interest were selected and identified by a fragment separator and then implanted in a passive plastic stopper. Delayed γ rays following internal isomeric decays were detected by the RISING array. Experimental information was obtained on a number of nuclei with Z = 73-80 (Ta-Hg), providing new information both on the prolate-oblate transitional region as well as on the N = 126 closed shell nuclei.

  14. Pressure ulcers and lateral rotation beds: a case study.

    PubMed

    Russell, Teresa; Logsdon, Angela

    2003-05-01

    During a 6-month period, the WOC nurses at a 500-bed medical treatment facility noticed the development of nosocomial pressure ulcers on the sacrum, occiput, and heel areas of patients who were placed on lateral rotation specialty beds because they had pulmonary disorders. Measures were taken to address the problem by repositioning the patients and through a staff education program. Repositioning included repositioning the patient's head every 2 hours, thorough skin assessments every 2 hours, and ensuring that the patient's heels were subject to zero pressure. Staff education centered on the importance of using a risk assessment tool (the Braden scale) and understanding the clinical uses for lateral rotation beds. During the subsequent 6 months, the incidence of hospital-acquired pressure ulcers decreased by 52%. Efforts to further decrease the number of pressure ulcers related to the use of lateral rotation beds continue. Issues such as length of stay on the bed and the appropriateness of manufacturer's guidelines still need to be addressed at this facility. This case study highlights the potential issues associated with lateral rotation beds and identifies the need for further research.

  15. The rotational barrier in ethane: a molecular orbital study.

    PubMed

    Quijano-Quiñones, Ramiro F; Quesadas-Rojas, Mariana; Cuevas, Gabriel; Mena-Rejón, Gonzalo J

    2012-04-20

    The energy change on each Occupied Molecular Orbital as a function of rotation about the C-C bond in ethane was studied using the B3LYP, mPWB95 functional and MP2 methods with different basis sets. Also, the effect of the ZPE on rotational barrier was analyzed. We have found that σ and π energies contribution stabilize a staggered conformation. The σ(s) molecular orbital stabilizes the staggered conformation while the stabilizes the eclipsed conformation and destabilize the staggered conformation. The π(z) and molecular orbitals stabilize both the eclipsed and staggered conformations, which are destabilized by the π(v) and molecular orbitals. The results show that the method of calculation has the effect of changing the behavior of the energy change in each Occupied Molecular Orbital energy as a function of the angle of rotation about the C-C bond in ethane. Finally, we found that if the molecular orbital energy contribution is deleted from the rotational energy, an inversion in conformational preference occurs.

  16. Numerical study on thermodynamic characteristics of rotational supercavitating evaporator

    NASA Astrophysics Data System (ADS)

    Li, Q.; Zheng, Z. Y.; Li, F. C.; Kulagin, V. A.

    2016-05-01

    Rotational Supercavitating Evaporator (RSCE) has been proposed as a new technology for seawater desalination. However, thermodynamic characteristics of rotational supercavitation are still vacant. In this paper, numerical simulations are conducted on the supercavitating flows around a 3D rotating blade of RSCE with different rotational speeds and extraction pressures. Energy effect is taken into consideration in the simulation and thermodynamic characteristics of rotational supercavitation are obtained. Rotational supercavitation has a larger convective heat transfer coefficient than the boiling on a heated wall.

  17. Multi-wavelength polarimetric studies of relativistic jets in active galactic nuclei

    NASA Astrophysics Data System (ADS)

    Casadio, Carolina

    This Thesis is focussed on the study of relativistic jets, commonly present in multiple astrophysical sites, from active galactic nuclei (AGN), to micro- quasars or gamma-ray bursts (GRBs). In the case of AGN, huge amounts of energy across the whole electromagnetic spectrum are released as a conse- quence of the accretion of material onto a supermassive back hole (SMBH) lurking at their centers. The accretion leads to the formation of a pair of very powerful and highly collimated jets extending far beyond the size of the host galaxy. We analyzed the correlation between the multi-wavelength emission and the radio jet in three powerful AGN, the radio galaxies 3C 120 and M 87, and the quasar CTA 102. The main goal of this Thesis is to obtain a better understanding of the jet dynamics and the role played by the magnetic field, and to determine what are the sites and mechanisms for the production of the γ-ray emission observed in these sources. We have performed multi-wavelength studies of the radio galaxy 3C 120 and the blazar CTA 102 during unprecedented γ-ray flares for both sources. The NASA satellite Fermi registered in September-October 2012 a bright γ-ray flare in CTA 102, and between December 2012 and October 2014 a prolonged γ-ray activity in the radio galaxy 3C 120. In both studies, to determine where the γ-ray emission is produced, the analysis of Fermi data has been compared with a detailed study of the morphology and evolution of the parsec scale jet through a series of extremely-high angular resolution Very Long Baseline Array (VLBA) images at 43 GHz from the Boston University blazar monitoring program, in which our research group is actively participating. In the case of 3C 120 we have also collected 15 GHz VLBA data from the MOJAVE monitoring program, extending our study of the radio jet from June 2008 to May 2014. For the study of CTA 102 a total of 80 VLBA images at 43 GHz have been analyzed and compared with observations across the whole

  18. Horizontal and vertical optic disc rotation. The Beijing Eye Study.

    PubMed

    Fan, Yuan Yuan; Jonas, Jost B; Wang, Ya Xing; Chen, Chang Xi; Wei, Wen Bin

    2017-01-01

    To measure the optic disc rotation around the vertical and horizontal disc axis and to evaluate associations with general and ocular parameters. Population-based study. In the Beijing Eye Study, 3468 participants (mean age:64.6±9.8 years; range:50-93 years) underwent an ophthalmological examination which included spectral-domain optical coherence tomography (OCT) with enhanced depth imaging. Using the OCT images, we determined the amount of the rotation of the optic disc (defined as Bruch´s membrane opening (BMO)) around the vertical axis and horizontal axis. Optic disc rotation measurements were available for 3037 (87.6%) individuals. In multivariate analysis, larger optic disc rotation around the vertical axis (range:-4.90° to 41.0°) was associated (regression coefficient r:0.27) with high axial myopia (axial length ≥26.5 mm) (P<0.001;standardized regression coefficient beta beta:0.09), longer disc-fovea distance (P = 0.001;beta:0.09) and wider parapapillary beta/gamma zone (P<0.001;beta0.12). Larger optic disc rotation around the horizontal axis (range:-7.10° to 26.4°) was associated (r:0.32) with high axial myopia (P = 0.001;beta:0.08), larger optic disc-fovea angle (P<0.001;beta:0.13), thinner superior nasal retinal nerve fiber layer (RNFL) thickness (P<0.001;beta:-0.19) and thicker inferior nasal RNFL thickness (P<0.001;beta:0.17). Vertical optic disc rotation was associated with highly myopic axial elongation, increased disc-fovea distance and development or enlargement of parapapillary, Bruch´s membrane free, gamma zone, while macular Bruch´s membrane length is not affected. Horizontal optic disc rotation was associated with inferior dislocation of the fovea, in addition to a thinner superior nasal RNFL and thicker inferior nasal RNFL. The latter association may be taken into account in the interpretation of RNFL thickness profiles.

  19. Cerebellar cortex and cerebellar nuclei are concomitantly activated during eyeblink conditioning: a 7T fMRI study in humans.

    PubMed

    Thürling, Markus; Kahl, Fabian; Maderwald, Stefan; Stefanescu, Roxana M; Schlamann, Marc; Boele, Henk-Jan; De Zeeuw, Chris I; Diedrichsen, Jörn; Ladd, Mark E; Koekkoek, Sebastiaan K E; Timmann, Dagmar

    2015-01-21

    There are controversies whether learning of conditioned eyeblink responses primarily takes place within the cerebellar cortex, the interposed nuclei, or both. It has also been suggested that the cerebellar cortex may be important during early stages of learning, and that there is a shift to the cerebellar nuclei during later stages. As yet, human studies have provided little to resolve this question. In the present study, we established a setup that allows ultra-high-field 7T functional magnetic resonance imaging (fMRI) of the cerebellar cortex and interposed cerebellar nuclei simultaneously during delay eyeblink conditioning in humans. Event-related fMRI signals increased concomitantly in the cerebellar cortex and nuclei during early acquisition of conditioned eyeblink responses in 20 healthy human subjects. ANOVAs with repeated-measures showed significant effects of time across five blocks of 20 conditioning trials in the cortex and nuclei (p < 0.05, permutation corrected). Activations were most pronounced in, but not limited to, lobules VI and interposed nuclei. Increased activations were most prominent at the first time the maximum number of conditioned responses was achieved. Our data are consistent with a simultaneous and synergistic two-site model of learning during acquisition of classically conditioned eyeblinks. Because increased MRI signal reflects synaptic activity, concomitantly increased signals in the cerebellar nuclei and cortex are consistent with findings of learning related potentiation at the mossy fiber to nuclear cell synapse and mossy fiber to granule cell synapse. Activity related to the expression of conditioned responses, however, cannot be excluded.

  20. Structure and symmetries of odd-odd triaxial nuclei

    NASA Astrophysics Data System (ADS)

    Palit, R.; Bhat, G. H.; Sheikh, J. A.

    2017-05-01

    Rotational spectra of odd-odd Rh and Ag isotopes are investigated with the primary motivation to search for the spontaneous chiral symmetry breaking phenomenon in these nuclei. The experimental results obtained on the degenerate dipole bands of some of these isotopes using a large array of gamma detectors are discussed and studied using the triaxial projected shell (TPSM) approach. It is shown that, first of all, to reproduce the odd-even staggering of the known yrast bands of these nuclei, large triaxial deformation is needed. This large triaxial deformation also gives rise to doublet band structures in many of these studied nuclei. The observed doublet bands in these isotopes are shown to be reproduced reasonably well by the TPSM calculations. Further, the TPSM calculations for neutron-rich nuclei indicate that the ideal manifestation of the chirality can be realised in 106Rh and 112Ag , where the doublet bands have similar electromagnetic properties along with small differences in excitation energies.

  1. Structure of doubly-even cadmium nuclei studied by βdecay

    NASA Astrophysics Data System (ADS)

    Rinta-Antila, S.; Wang, Y.; Dendooven, P.; Huikari, J.; Jokinen, A.; Kankainen, A.; Kolhinen, V. S.; Lhersonneau, G.; Nieminen, A.; Nummela, S.; Penttilä, H.; Peräjärvi, K.; Szerypo, J.; Wang, J. C.; Äystö, J.

    2005-09-01

    We have studied the structure of even-even cadmium isotopes via beta decay of ground and excited isomeric states of parent silver isotopes. Measurements of mass A = 116, 118 and 120 cadmium nuclides were carried out at an ion guide isotope separation on-line facility at the University of Jyväskylä. Decay schemes of 116mAg, 118mAg, 120gAg and 120mAg are considerably extended. Obtained data have enabled extension of available systematics of the three-phonon states to more neutron-rich cadmium nuclei. As a continuation we have conducted an experiment at ISOLDE, CERN to study heavier A = 122, 124, and 126 cadmium nuclides, the analysis of the collected data is underway.

  2. Rotational studies of late-type stars. III - Rotation among BY Draconis stars

    NASA Astrophysics Data System (ADS)

    Vogt, S. S.; Penrod, G. D.; Soderblom, D. R.

    1983-06-01

    High-resolution line profiles have been obtained and v sin i's measured for 17 K and M dwarfs. All BY Draconis stars (whether single or in binaries) rotate more rapidly than other K and M dwarfs, reinforcing previous suggestions that rapid rotation (≥5 km s-1) is the underlying cause of the BY Draconis syndrome.

  3. Single Particle Orientation and Rotational Tracking (SPORT) in biophysical studies

    NASA Astrophysics Data System (ADS)

    Gu, Yan; Ha, Ji Won; Augspurger, Ashley E.; Chen, Kuangcai; Zhu, Shaobin; Fang, Ning

    2013-10-01

    The single particle orientation and rotational tracking (SPORT) techniques have seen rapid development in the past 5 years. Recent technical advances have greatly expanded the applicability of SPORT in biophysical studies. In this feature article, we survey the current development of SPORT and discuss its potential applications in biophysics, including cellular membrane processes and intracellular transport.The single particle orientation and rotational tracking (SPORT) techniques have seen rapid development in the past 5 years. Recent technical advances have greatly expanded the applicability of SPORT in biophysical studies. In this feature article, we survey the current development of SPORT and discuss its potential applications in biophysics, including cellular membrane processes and intracellular transport. Electronic supplementary information (ESI) available: Three supplementary movies and an experimental section. See DOI: 10.1039/c3nr02254d

  4. A rotating disk study of gold dissolution by bromine

    NASA Astrophysics Data System (ADS)

    Pesic, Batric; Sergent, Rodney H.

    1991-12-01

    Gold dissolution with bromine was studied using the rotating disk technique with Geobrom™ 3400 as a source of bromine. The parameters studied were speed of rotation, lixiviant concentration, pH, temperature, sulfuric acid and hydrochloric acid concentrations, and the concentrations of various cations (i.e., copper, iron, zinc, aluminum, manganese, potassium, and sodium) and anions (i.e., chloride, bromide, sulfate, nitrate, and iodide). According to the Lavich plot and activation energy, gold dissolution is controlled by a chemical reaction rate. Copper, iron, and manganese in their highest oxidation states, as well as aluminum, zinc, sodium, and potassium, have no effect on the rate of gold dissolution. The presence of manganous ion substantially decreases the gold dissolution rate. The kinetic performance of bromine was found to be dramatically better than the performance of cyanide and thiourea.

  5. Microwave Rotational Spectral Study of SO2-CO

    PubMed Central

    Lovas, F. J.; Sprague, M. K.

    2016-01-01

    The microwave spectrum of the molecular complex of sulfur dioxide (SO2) with carbon monoxide (CO) has been studied with a pulsed-beam Fourier Transform Microwave Spectrometer (FTMW) from a pair of gas samples of 1 % by volume of SO2 and CO in Ar, and introduced via separate capillary inputs to the flow nozzle. The frequency coverage was about 7 GHz to 16 GHz for various isotopomers. The molecular structure was determined with the aid of spectral studies of isotopically substituted monomers containing 13C, 18O and 34S. The rotational analyses provide the rotational and centrifugal distortion constants for all of the isotopomers analyzed. The structure determination is compared to detailed ab initio structural calculations. The electric dipole moment components along the a- and c-axis were determined from Stark effect measurements. PMID:27239070

  6. Ab initio study of the rotational energy barrier in carbonylylide

    NASA Astrophysics Data System (ADS)

    Jean, Y.; Volatron, F.

    1981-10-01

    The rotational energy barrier in carbonylylide CH 2OCH 2 is studied using RHF CI calculations. Depending on the size of the CI and the basis set (STO-3G and 4-31G), values in the range 13-17 kcal/mol are found. At this level of calculation, the mid-point of the isomerization process can be mainly described by the diradical rather than the zwitterion.

  7. Germany-US Nuclear Theory Exchange Program for QCD Studies of Hadrons & Nuclei 'GAUSTEQ'

    SciTech Connect

    Dudek, Jozef; Melnitchouk, Wally

    2016-03-07

    GAUSTEQ was a Germany-U.S. exchange program in nuclear theory whose purpose was to focus research efforts on QCD studies of hadrons and nuclei, centered around the current and future research programs of Jefferson Lab and the Gesellschaft fur Schwerionenforschung (GSI) in Germany. GAUSTEQ provided travel support for theoretical physicists at US institutions conducting collaborative research with physicists in Germany. GSI (with its Darmstadt and Helmholtz Institute Mainz braches) served as the German “hub” for visits of U.S. physicists, while Jefferson Lab served as the corresponding “hub” for visits of German physicists visiting U.S. institutions through the reciprocal GUSTEHP (German-US Theory Exchange in Hadron Physics) program. GAUSTEQ was funded by the Office of Nuclear Physics of the U.S. Department of Energy, under Contract No.DE-SC0006758 and officially managed through Old Dominion University in Norfolk, Virginia. The program ran between 2011 and 2015.

  8. Study of weakly-bound odd-A nuclei with quasiparticle blocking

    NASA Astrophysics Data System (ADS)

    Xiong, Xue-Yu; Pei, Jun-Chen; Zhang, Yi-Nu; Zhu, Yi

    2016-02-01

    The coordinate-space Hartree-Fock-Bogoliubov (HFB) approach with quasiparticle blocking has been applied to study the odd-A weakly bound nuclei 17,19B and 37Mg, in which halo structures have been reported in experiments. The Skyrme nuclear forces SLy4 and UNEDF1 have been adopted in our calculations. The results with and without blocking have been compared to demonstrate the emergence of deformed halo structures due to blocking effects. In our calculations, 19B and 37Mg have remarkable features of deformed halos. Supported by National Key Basic Research Program of China (2013CB83440), National Natural Science Foundation of China (11375016, 11235001, 11320101004) and Research Fund for Doctoral Program of Higher Education of China (20130001110001)

  9. Transfer reaction studies in the region of heavy and superheavy nuclei at SHIP

    NASA Astrophysics Data System (ADS)

    Heinz, S.; Comas, V.; Hofmann, S.; Ackermann, D.; Heredia, J.; Heβberger, F. P.; Khuyagbaatar, J.; Kindler, B.; Lommel, B.; Mann, R.

    2011-02-01

    We studied multi-nucleon transfer reactions in the region of heavy and superheavy nuclei. The goal was to investigate these reactions as possibility to create new superheavy neutron-rich isotopes, which cannot be produced in fusion reactions. The experiments have been performed at the velocity filter SHIP at GSI. At SHIP we can detect and identify the heavy, target-like, transfer products. Due to the low background at the focal plane detector and the isotope identification via radioactive decays, the setup allows to reach an upper cross-section limit of 10 pb/sr within one day of beamtime. We investigated the systems 58,64Ni + 207Pb and 48Ca + 248Cm at beam energies below and up to 20% above the Coulomb barrier. At all energies we observed a massive transfer of protons and neutrons, where transfer products with up to eight neutrons more than the target nucleus could be identified.

  10. Ultracold Rotational Quenching Study of CO with H+

    NASA Astrophysics Data System (ADS)

    Kaur, Rajwant; Kumar, T. J. Dhilip

    2016-05-01

    Cooling and trapping of polar molecules have stimulated research in precise monitoring and controlling dynamics in ultracold regime. There has been considerable interest in the study of molecular inelastic collision processes at cold and ultracold temperatures. Collisional study of polar interstellar species CO, adds an additional astrophysical importance to model interstellar medium. Present work focuses on rotational quenching of abundant interstellar species, CO with H+ using quantum-mechanical scattering calculation. Rate coefficients for molecular rotational transitions of CO due to collision with H+ are obtained in the range of 10-5 K to 200 K from cross sections which are computed using close coupling calculations as implemented in MOLSCAT. The data generated from ultracold to higher temperatures assist in investigating the chemistry of interstellar clouds. Calculations are performed on ground state ab initio potential energy surface using MRCI/cc-pVTZ method. Rotational transitions are studied in the rigid-rotor approximation with CO bond length fixed at an equilibrium value of 2.138 a.u. Asymptotic potentials are computed using the dipole and quadrupole moments, and the dipole polarizability components.

  11. Mode Coupling Studies in an RFP with Rotating Helical Field

    NASA Astrophysics Data System (ADS)

    Masamune, Sadao; Iida, Motomi

    2001-10-01

    Nonlinear coupling of m=1 modes play essential roles in RFP dynamics such as field reversal, RFP dynamo and mode locking. In the RFP with a resistve wall, the mode coupling is enhanced because of larger saturation amplitudes of the core resonant tearing modes. The mode coupling usually brings about unfavorable effect on RFP plasmas, and therefore, studies on detailed coupling process is quite important. In this paper, we describe the mode coupling studies from STE-2 RFP (R/a=0.4m/0.1m) with rotating helical field (RHF). This machine is operated with a resistive wall and the effect of external RHF is studied on the dynamics of core resonant tearing modes. In standard RFP plasmas, the magnetic fluctuations are dominated by core resonant m=1/n=7,8,9 tearing modes which grow with the time scale of resistive wall. These modes, usually locked to the wall, start to rotate with application of the RHF when the RHF amplitude is higher than that of the intrinsic mode at the edge. In ULQ plasmas in which there is no m=0 resonant surface and the m=1 modes usually rotate, only a single mode is locked to the wall with application of the static resonant helical field. These results suggest the importance of nonlinear coupling of the m=1 and m=0 modes, and detailed measurements of the dynamics of m=1 and m=0 modes are in progress.

  12. The effect of rotator cuff repair on early overhead shoulder function: a study in 1600 consecutive rotator cuff repairs.

    PubMed

    Robinson, Hayden A; Lam, Patrick H; Walton, Judie R; Murrell, George A C

    2017-01-01

    Rotator cuff tears are often surgically repaired, generally with good results. However, repairs not infrequently retear, and how important repair integrity is with respect to early functional outcomes after rotator cuff repair is unclear. Thus, the purpose of this study was to determine the effect of a retear on overhead activities in a large cohort of patients after rotator cuff repair. This was a retrospective cohort study of prospectively collected data from 1600 consecutive rotator cuff repairs. Outcomes were based on patient responses to the L'Insalata Shoulder Questionnaire and findings on examination preoperatively and at 6 months of follow-up. Repair integrity was determined by ultrasound imaging at the 6-month follow-up visit. The 1600 patients (885 men, 715 women) were a mean age of 58 years. Postoperative ultrasound imaging found 13% (211 of 1600) of repairs had retorn. Significant improvements were seen irrespective of rotator cuff integrity in pain levels with overhead activity (P < .0001) and range of motion in forward flexion (P < .001) and abduction (P < .01). Patients with intact repairs had 9.5 N greater supraspinatus strength (P < .0001) and 6.9 N greater external rotation strength (P < .01) than those with a retear. To our knowledge, this is the largest study to evaluate the effect of rotator cuff repair integrity on shoulder function. Patients who had an arthroscopic rotator cuff repair reported significant improvements in overhead pain levels irrespective of the repair integrity at 6 months. Repair integrity influenced supraspinatus and external rotation power, where patients with intact repairs were stronger than those with a retear. Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

  13. Studies on exotic nuclei by proton-induced direct reaction at GSI and FAIR

    SciTech Connect

    Kiselev, O. A.

    2007-02-26

    The proton-induced direct reactions like elastic, quasi-elastic scattering and knock-out at intermediate energies and inverse kinematics are the most powerful classical methods for obtaining spectroscopic information on the structure of unstable exotic nuclei. Few elastic scattering experiments performed at GSI with the gaseous and liquid hydrogen targets provided the most precise data on a nuclear matter distribution and a halo-core structure of the neutron-rich He and Li isotopes. The measured differential cross sections have been also used for probing density distributions as predicted by various microscopic theories. The comparison of the data with the latest calculations will be shown. The description of the recent experiment with proton-rich 8B and neutron-rich Be isotopes is presented.The experimental conditions at the future facility FAIR will provide unique opportunities for nuclear structure studies on nuclei far off stability, and will allow to reach new regions in the chart of nuclides of high interest for nuclear structure and astrophysics. In particular, predicted luminosity will allow for the investigation of direct reactions with stored and cooled radioactive beams at internal H, He, etc. targets of the storage ring NESR. This technique enables high resolution measurements down to very low momentum transfer and provides a gain in luminosity from accumulation and recirculation of the radioactive beams. In order to explore the experimental conditions for measurements planned at EXL/FAIR setup, a first attempt exploring experimentally the feasibility of its concept has been recently made. A detector setup was installed at the ESR storage ring at GSI, Darmstadt. A 136Xe beam was interacting to an internal hydrogen gas-jet target. The detector setup had all the basic ingredients as foreseen by EXL collaboration. A set of scattering reactions has been studied and the overall performance of the setup demonstrated the feasibility of the EXL experimental

  14. Conversion electron spectroscopy at the FMA focal plane: Decay studies of proton-rich N {approximately} 82 nuclei

    SciTech Connect

    Nisius, D.; Janssens, R.V.F.; Ahmad, I.

    1995-08-01

    The FMA has proven to be an ideal instrument for the detailed study of the decay of microsecond isomers behind the focal plane following mass selection. In reactions leading to the population of nuclei with isomeric lifetimes longer than their flight time through the device, decay gamma rays and conversion electrons can be detected in an environment free from the backgrounds of prompt radiation and delta electrons. This was a very successful technique to study proton (h{sub 11/2}){sup n} seniority isomers in nuclei with Z > 64 and N {approximately} 82. Since isomeric decay gamma rays are emitted isotropically, conversion electrons are essential for the assignment of multipolarities in these nuclei. Furthermore, the low-energy transitions that depopulate isomeric states are typically highly converted and can escape gamma-ray detection, but they can be identified by their conversion electrons.

  15. Neurons in the Cochlear Nuclei Controlling the Tensor Tympani Muscle in the Rat: a Study Using Pseudorabies Virus

    PubMed Central

    Billig, I.; Yeager, M.S.; Blikas, A.; Raz, Y.

    2010-01-01

    The middle ear muscle reflex has been implicated in modulation of auditory input and protection of the inner ear from acoustic trauma. However, the identification of neurons in the cochlear nuclei participating in this reflex has not been fully elucidated. In the present study, we injected the retrograde transynaptic tracer pseudorabies virus into single tensor tympani (TT) muscles, and identified transynaptically labeled cochlear nucleus neurons at multiple survival times. Motoneurons controlling TT were located ventral to the ipsilateral motor trigeminal nucleus and extended rostrally towards the medial aspect of the lateral lemniscus. Transynaptically-labeled neurons were observed bilaterally in the dorsal and dorso-medial parts of ventral cochlear nuclei as early as 48 h after virus injection, and had morphological features of radiate multipolar cells. After ≥ 69 h, labeled cells of different types were observed in all cochlear nuclei. At those times, labeling was also detected bilaterally in the medial nucleus of the trapezoid body and periolivary cell groups in the superior olivary complex. Based on the temporal course of viral replication, our data strongly suggest the presence of a direct projection of neurons from the ventral cochlear nuclei bilaterally to the TT motoneuron pool in rats. The influence of neurons in the cochlear nuclei upon TT activity through direct and indirect pathways may account for multifunctional roles of this muscle in auditory functions. PMID:17482147

  16. Study of few body Kaonic Nuclei using the method of hyperspherical functions in momentum representation

    NASA Astrophysics Data System (ADS)

    Kezerashvili, Roman; Tsiklauri, Shalva

    2014-03-01

    Kaonic three-body K- NN, and of four-body K-NNN and K-K-NN nuclei are studied within the method of hyperspherical functions in momentum representation, using realistic local and separable potential models for NN and KN as well as for KK interactions. We solve nonrelativistic three- and four-body Schrodinger equation in momentum representation in the framework of the method of hyperspherical harmonics to find a ground state binding energy and corresponding wave function. The following ground-state binding energies were obtained: 48.3 MeV (K-pp), 28.2 MeV (K-K-p), 67.2 MeV (K-ppn), and 89.3 MeV (K-K-pp), which are in good agreement with previous results obtained for the same potentials using Faddeev equations and variational method. There are theoretical discrepancies relating to the binding energy of kaonic nuclei, coming from the different KN and KK interactions. Using AV4 NN (Wiringa, Pieper, Phys. Rev. Lett. 89, 182501, 2002) potential and energy dependent chiral KN and KK local potentials (Barnea et al., Phys. Lett. B 712, 132, 2012) we received the following results of the binding energies 13.9 Mev (KNN) ½,0 , 27.3 Mev (K NNN)I=0 and 30.4 MeV (K-KNN)I=0. The results of our calculations are in agreement with results of Barnea et al. The experimental evidences to support theoretical predictions are discussed. This research is supported by CUNY Research Grant Program C3IRG.

  17. Beta Decay Studies of Proton Rich Nuclei, an Important Ingredient for rp-Process Calculations

    NASA Astrophysics Data System (ADS)

    Rubio, B.; Kucuk, L.; Orrigo, S. E. A.; Fujita, Y.; Gelletly, W.; Blank, B.; Adachi, T.; Aguilera, P.; Agramunt, J.; Algora, A.; Ascher, P.; Bilgier, B.; Cáceres, L.; Cakirli, R. B.; de France, G.; de Oliveira Santos, F.; Fujita, H.; Ganioğlu, E.; Gerbaux, M.; Giovinazzo, J.; Grévy, S.; Kamalou, O.; Kozer, H. C.; Kurtukian-Nieto, T.; Marqués, M.; Molina, F.; Nishimura, D.; Oikawa, H.; Oktem, Y.; Perrot, L.; Popescu, L.; Raabe, R.; Rogers, A. M.; Srivastava, P. C.; Susoy, G.; Stodel, C.; Suzuki, T.; Tamii, A.; Thomas, J. C.

    We have performed a series of beta-decay experiments at fragmentation facilities on Tz = -1/2, Tz = -1, and Tz = -2 nuclei. Most of these nuclei lie on the rp-process path and therefore some of the quantities we have measured such as T1/2 values are important ingredients in performing reaction flow calculations for light curve estimates and testing astrophysical models of X-ray bursters. At this conference we have presented the results of measurements of T1/2 values for 25 nuclei and compared with previous values.

  18. Laboratory studies of isolated eddies in a rotating fluid

    NASA Astrophysics Data System (ADS)

    Whitehead, J. A.

    Numerous laboratory techniques have been used to generate isolated eddies in a rotating fluid, but they can all be divided into two categories; those in which the eddies are directly produced by inserting or withdrawing fluid, and those in which eddies are produced by an instability or separation process. Two examples are reviewed for the latter category. Dipole eddies in a homogeneous rotating fluid have been produced by Flierl, Stern, and Whitehead. In most cases, modification was observed due to a third vortex. This is usually accompanied by a curved track of the vortex pairs. Recent studies have focused on isolated eddies which form from rather general and nondescript initial conditions. Baroclinic eddies in a rotating fluid with a sloping bottom were produced by squirting dense salt water up the sloping bottom and along the eastern wall. The jet stagnated in shallow water and was ejected normal to the wall. For certain parameters (volume flux of jet, etc.), a coherent lens of dense bottom water formed and propagated west with an overlying cyclonic vortex. The circulation in the bottom lens, on the other hand, was relatively weak. No such eddy forms when the depth of fresh water is relatively deep, and a regime diagram is given for the formation of the coherent eddies. The pressure field determined from analysis of the density distribution and using streak photographs is discussed in terms of an integral theorem for coherent eddies. The westward propagation is also related to previous theories.

  19. Spatial Compounding Technique to Obtain Rotation Elastogram: A Feasibility Study.

    PubMed

    Kothawala, AliArshad; Chandramoorthi, Sowmiya; Reddy, N Ravi Kiran; Thittai, Arun Kumar

    2017-06-01

    The perception of stiffness and slipperiness of a breast mass on palpation is used by physicians to assess the level of suspicion of a lesion as being malignant or benign. However, most current ultrasound elastography imaging methods provide only stiffness-related information. There is no existing approach that provides information about the local rigid body rotation undergone by only a loosely bonded, asymmetrically oriented lesion subjected to a small quasi-static compression. The inherent poor lateral resolution in ultrasound imaging poses a limitation in estimating the local rigid body rotation. Several techniques have been reported in the literature to improve the lateral resolution in ultrasound imaging, and among them is spatial compounding. In this study, we explore the feasibility of obtaining better-quality rotation elastograms with spatial compounding through simulations using Field II and experiments on tissue-mimicking phantoms. The phantom was subjected to axial compression (∼1%-2%) from the top, and the angular axial and lateral displacement estimates were obtained using a multilevel 2-D displacement tracking algorithm at different insonification angles. A rotation elastogram (RE) was obtained by taking half of the difference between the lateral gradient of the axial displacement estimates and the axial gradient of the lateral displacement estimates. Contrast-to-noise ratio was used to quantify the improvements in quality of RE. Contrast-to-noise ratio values were calculated by varying the maximum steering angle and the incremental angle, and its effects on RE quality were evaluated. Both simulation and experimental results corroborated and indicated a significant improvement in the quality of RE using compounding technique. Copyright © 2017 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  20. Possibilities of studying the structure of halo nuclei in reactions of quasifree proton scattering at low energies

    SciTech Connect

    Zuyev, S. V. Kasparov, A. A.; Konobeevski, E. S.

    2015-07-15

    The possibility of experimentally studying the structure of halo nuclei in reactions induced by quasifree proton scattering on clusters of these nuclei is considered. Quasifree proton scattering on {sup 6}He, {sup 4}He, {sup 4}n, {sup 2}n, and n clusters in inverse kinematics is considered for the example of the {sup 8}He nucleus. Angular and energy distributions of secondaries are obtained for various representations of the cluster structure of the {sup 8}He nucleus. It is clearly shown that, in the angular and energy distributions of secondaries, one can single out regions that receive dominant contributions from reactions on specific clusters and which correspond to concrete cluster configurations of halo nuclei. Possible relevant experiments are proposed.

  1. Isolation of Nuclei.

    PubMed

    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.

  2. The study of lunar rotation by Japanese lunar landing missions

    NASA Astrophysics Data System (ADS)

    Kikuchi, Fuyuhiko; Hanada, Hideo; Noda, Hirotomo; Sasaki, Sho; Iwata, Takahiro

    2010-05-01

    The internal structure of the planet is one of the important clues to know its origin and evolution. So far, gravity, rotation, seismic wave, electro-magnetic wave, and heat flow observations have been carried out. In these methods, we plan to load rotation estimation instrument for next Japanese lunar exploration project SELENE-2 and SELENE-3. LLR: The Lunar Laser Ranging (LLR) is the method to measure the distance between the Earth and the Moon using laser beam. For more than 30 years since the Apollo and the Lunokhod mission placed retrograde reflectors on the Moon, LLR produced data on the lunar rotation as well as the lunar orbital evolution. On the basis of LLR data, the state of lunar interior is discussed. Williams discussed the dissipation between the solid mantle and a fluid core from LLR data. LLR observation has also provided information of moment of inertia and tidal Love number of the Moon. We are proposing a new LLR on board SELENE-II. Instead of conventional corner cube reflector (CCR) array, we are planning to use a larger single reflector. This has an advantage over the conventional CCR array, because a single cube should have smaller distance variation within the reflector upon monthly libration of the lunar rotation. We are proposing that a new reflector should be somewhere in the southern hemisphere on the nearside Moon. Then in combination with a powerful A15 CCR, latitudinal component of lunar libration and its dissipation can be measured precisely. We also prepare the inverse-VLBI and ILOM (In situ Lunar Orientation Measurement) missions for post-SELENE-2 mission. ILOM: ILOM is a selenodetic mission to study lunar rotational dynamics by direct observations of the lunar physical libration and the free librations from the lunar surface with an accuracy of 1 millisecond of arc in the post-SELENE project. Year-long trajectories of the stars provide information on various components of the physicallibrations and we will also try to detect the

  3. Studies of multi-quasiparticle k-isomers in rare-earth and trans-fermium nuclei.

    SciTech Connect

    Kondev, F. G.; Dracoulis, G. D.; Khoo, T. L.; Lane, G. J.; Byrne, A. P.; Kibedi, T.; Ahmad, I.; Carpenter, M. P.; Janssens, R. V. F.; Lauritzen, T.; Lister, C. J.; Seweryniak, D.; Zhu, S.; Chowdhury, P.; Tandel, S. K.; Australian National Univ.; Univ. of Massachusetts Lowell

    2007-01-01

    Nuclear K-isomers play an important role in understanding the structure of deformed axially symmetric nuclei. Examples are presented of recent studies in the rare-earth region (A {approx} 180) using deep-inelastic and multi-nucleon transfer reactions, and in the trans-fermium region (A {approx} 250) using fusion-evaporation reactions. A specific two-level mixing scenario is invoked to explain the unusual decay of the K{sup {pi}} = 13{sup +} isomer in {sup 174}Lu. The identification of 2- and 4-quasiparticle isomers in {sup 254}No is discussed and predictions of similar isomers in neighboring No and Rf nuclei are presented.

  4. Generalized Rotational Susceptibility Studies of Solid 4He

    NASA Astrophysics Data System (ADS)

    Gadagkar, V.; Pratt, E. J.; Hunt, B.; Yamashita, M.; Graf, M. J.; Balatsky, A. V.; Davis, J. C.

    2012-11-01

    Using a novel SQUID-based torsional oscillator (TO) technique to achieve increased sensitivity and dynamic range, we studied TO's containing solid 4He. Below ˜250 mK, the TO resonance frequency f increases and its dissipation D passes through a maximum as first reported by Kim and Chan. To achieve unbiased analysis of such 4He rotational dynamics, we implemented a new approach based upon the generalized rotational susceptibility χ{4He}^{ - 1}(ω,T). Upon cooling, we found that equilibration times within f( T) and D( T) exhibit a complex synchronized ultraslow evolution toward equilibrium indicative of glassy freezing of crystal disorder conformations which strongly influence the rotational dynamics. We explored a more specific χ{4He}^{ -1}(ω,tau(T)) with τ( T) representing a relaxation rate for inertially active microscopic excitations. In such models, the characteristic temperature T ∗ at which df/ dT and D pass simultaneously through a maximum occurs when the TO angular frequency ω and the relaxation rate are matched: ωτ( T ∗)=1. Then, by introducing the free inertial decay (FID) technique to solid 4He TO studies, we carried out a comprehensive map of f( T, V) and D( T, V) where V is the maximum TO rim velocity. These data indicated that the same microscopic excitations controlling the TO motions are generated independently by thermal and mechanical stimulation of the crystal. Moreover, a measure for their relaxation times τ( T, V) diverges smoothly everywhere without exhibiting a critical temperature or velocity, as expected in ωτ=1 models. Finally, following the observations of Day and Beamish, we showed that the combined temperature-velocity dependence of the TO response is indistinguishable from the combined temperature-strain dependence of the 4He shear modulus. Together, these observations imply that ultra-slow equilibration of crystal disorder conformations controls the rotational dynamics and, for any given disorder conformation, the

  5. Superdeformed nuclei

    SciTech Connect

    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.

  6. Granular ripples under rotating flow: a new experimental technique for studying ripples in non-rotating, geophysical applications?

    PubMed

    Thomas, P J; Zoueshtiagh, F

    2005-07-15

    A review of our research investigating a new pattern formation process in granular material underlying a rotating fluid is given. The purpose of this summary is to introduce the phenomenon to the geophysical research community and to draw attention to the potential practical benefits of our new experimental method. To this end, the applied and scientific advantages of the technique over traditional studies employing, for instance, water channels, are discussed for the first time. It is shown here that the system rotation in our new technique does not appear to affect the scaling law expressing the dependence of the ripple-pattern wavelength on the governing independent experimental parameters. This suggests that it may become possible to extrapolate appropriate results from rotating to non-rotating systems and, hence, to geophysical environments. Consequently, our new technique may find applications in the context of geophysical research on the formation of sedimentary granular ripple structures.

  7. Coupled-Channels Study of α-DECAY Rates for Deformed Nuclei

    NASA Astrophysics Data System (ADS)

    Ni, Dongdong; Ren, Zhongzhou

    The generalized density-dependent cluster model is devoted to calculate α-decay half-lives of spherical and deformed nuclei. The multi-channel cluster model is developed to describe the α-decay fine structure in heavy deformed nuclei, including half-lives and branching ratios. After a brief review of these two models, special cases of the α-decay fine structure are presented. Calculations are separately performed using the coupled-channels and WKB approaches.

  8. Studies on cluster decay from trans-lead nuclei using different versions of nuclear potentials

    NASA Astrophysics Data System (ADS)

    Santhosh, K. P.; Sukumaran, Indu

    2017-06-01

    The cluster decays from various isotopes of trans-lead nuclei have been studied using 12 different nuclear potentials by evaluating decay half-lives and are then compared with the available experimental data. The study has shown that the barrier penetrability as well as the decay half-lives varies with the nuclear potential used. The standard deviation of the estimated half-lives is also calculated for these twelve nuclear potentials in comparison with the experimental data. The potential Bass 1980 is found to be the most appropriate potential for studying cluster radioactivity as the standard deviation obtained is least. Among the different proximity potential versions; proximity 1977, proximity 1988, proximity 2000, and modified proximity 2000, the minimum standard deviation is for proximity 1988. The Geiger-Nuttall (G-N) plots studied for different cluster emissions from various parents are observed to show linear behavior but with different slopes and intercepts. Again, the G-N plots obtained are linear with different slopes and intercepts when plotted for different nuclear potentials. So it is observed that with the inclusion of different nuclear potentials, the linearity of the G-N plot remains unaltered. Irrespective of the nuclear potential used, the universal curve (log_{10}T_{1/2} vs. - ln P) studied for various clusters emitted from various parents are obtained as linear with same slope and intercept.

  9. Study of Complete Fusion Reactions Leading to the Production of Heavy and Superheavy Nuclei

    SciTech Connect

    Roman N. Sagaidak

    1999-12-31

    Cross section values for heavy evaporation residues (ER) produced in complete fusion reactions induced by heavy ions on spherical and deformed target nuclei are analyzed in the framework of barrier penetration and statistical model approximations. For the reactions leading to Rn-Pa nuclei, a strong influence of the entrance channel on the measured cross section values is observed for nearly symmetric projectile-target combinations. In order to reproduce the observed excitation functions in such combinations we had to introduce the quantity of fusion probability. Considering the asymmetric reactions leading to the heaviest nuclei we also had to use the fusion probability to reproduce the cross section values obtained for cold fusion reactions induced by {sup 50}Ti and heavier projectiles on the Pb and Bi target nuclei, and also the values obtained for hot fusion reactions induced by {sup 34}S on actinide target nuclei. The scaling of fusion probabilities derived for both the reactions allowed us to predict the values of cross sections for superheavy elements (SHE) produced in the {sup 48}Ca induced reactions on actinide target nuclei and in the cold fusion reactions induced by the Zn and heavier projectiles.

  10. Study of complete fusion reactions leading to the production of heavy and superheavy nuclei

    SciTech Connect

    Sagaidak, Roman N.

    1999-11-16

    Cross section values for heavy evaporation residues (ER) produced in complete fusion reactions induced by heavy ions on spherical and deformed target nuclei are analyzed in the framework of barrier penetration and statistical model approximations. For the reactions leading to Rn-Pa nuclei, a strong influence of the entrance channel on the measured cross section values is observed for nearly symmetric projectile-target combinations. In order to reproduce the observed excitation functions in such combinations we had to introduce the quantity of fusion probability. Considering the asymmetric reactions leading to the heaviest nuclei we also had to use the fusion probability to reproduce the cross section values obtained for cold fusion reactions induced by {sup 50}Ti and heavier projectiles on the Pb and Bi target nuclei, and also the values obtained for hot fusion reactions induced by {sup 34}S on actinide target nuclei. The scaling of fusion probabilities derived for both the reactions allowed us to predict the values of cross sections for superheavy elements (SHE) produced in the {sup 48}Ca induced reactions on actinide target nuclei and in the cold fusion reactions induced by the Zn and heavier projectiles.

  11. β-delayed Neutron Decay Studies of r-process Nuclei near ^137Sb

    NASA Astrophysics Data System (ADS)

    Santi, P.; Schatz, H.; Mahmud, H.; Woods, P. J.; Attallah, F.; Geissel, H.; Hausmann, M.; Hellström, M.; Münzenberg, G.; Scheidenberger, C.; Schmidt, K.; Sümmerer, K.; Stadlmann, J.; Mineva, M. N.; Hannawald, M.; Kratz, K.-L.; Pfeiffer, B.; Faestermann, T.; Schneider, R.; Stolz, A.; Wefers, E.; Giesen, U.

    2002-10-01

    In order to understand r-process nucleosynthesis, it is necessary to know the β-decay half lives and neutron emission probabilities (P_n) of the neutron rich nuclei which lie along the r-process path. To this end an experiment was performed at GSI to measure the T_1/2 and Pn values of r-process nuclei around the waiting-point nucleus ^137Sb. The nuclei of interest were produced via the projectile fission of a 750 MeV/nucleon ^238U beam and identified using the FRS fragment separator. A stack of 4 double-sided silicon strip detectors were used to detect the implanted nuclei and subsequent β-decays. Neutrons emitted from β-delayed neutron decays were detected using the Mainz 4π neutron long counter. A set of approximately 10 r-process nuclei in the A=130 region, including the waiting-point nuclei ^136Sn and ^137Sb, were measured during the experiment. Preliminary results of the experiment will be discussed.

  12. Assessing Tibial Tray Rotation in TKA: A Cadaveric Study.

    PubMed

    Hakki, Sam; El-Othmani, Mouhanad M; Gabriel, Christian; Mihalko, William M; Saleh, Khaled J

    2016-05-01

    Tibial anatomical landmarks for transverse plane rotation of the tibial tray have not been validated. The current authors propose aligning the tibial tray with both the anterior tibial center point of rotation (ATCPR) and the femoral trochlear groove (FTG) to establish the ideal tibial tray rotation in total knee arthroplasty (TKA). When the tibial tray centerline was aligned with ATCPR and FTG lines, the mean range of motion (ROM) was 144.3° (preoperatively 145°) and tibial rotation range was 22.8 mm (preoperatively, 24.9 mm). When the tibial component was rotated 5 mm medially to the ATCPR, the knee ROM decreased in flexion with patellar subluxation, while it decreased in extension when rotated 5 mm laterally. This method identifies the ideal tibial tray rotation in TKA, at which maximal range of tibial rotation and knee ROM are achieved without obvious overriding of components. [Orthopedics, 2016; 39(3):S67-S71.]. Copyright 2016, SLACK Incorporated.

  13. The Relationship Between Shoulder Stiffness and Rotator Cuff Healing: A Study of 1,533 Consecutive Arthroscopic Rotator Cuff Repairs.

    PubMed

    McNamara, William J; Lam, Patrick H; Murrell, George A C

    2016-11-16

    Retear and stiffness are not uncommon outcomes of rotator cuff repair. The purpose of this study was to evaluate the relationship between rotator cuff repair healing and shoulder stiffness. A total of 1,533 consecutive shoulders had an arthroscopic rotator cuff repair by a single surgeon. Patients assessed their shoulder stiffness using a Likert scale preoperatively and at 1, 6, 12, and 24 weeks (6 months) postoperatively, and examiners evaluated passive range of motion preoperatively and at 6, 12, and 24 weeks postoperatively. Repair integrity was determined by ultrasound evaluation at 6 months. After rotator cuff repair, there was an overall significant loss of patient-ranked and examiner-assessed shoulder motion at 6 weeks compared with preoperative measurements (p < 0.0001), a partial recovery at 12 weeks, and a full recovery at 24 weeks. Shoulders that were stiff before surgery were more likely to be stiff at 6, 12, and, to a lesser extent, 24 weeks after surgery (r = 0.10 to 0.31; p < 0.0001). A stiffer shoulder at 6 and 12 weeks (but not 24 weeks) postoperatively correlated with better rotator cuff integrity at 6 months postoperatively (r = 0.11 to 0.18; p < 0.001). The retear rate of patients with ≤20° of external rotation at 6 weeks postoperatively was 7%, while the retear rate of patients with >20° of external rotation at 6 weeks was 15% (p < 0.001). In patients who developed stiffness after surgery, a rotator cuff repair was more likely to heal. Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence. Copyright © 2016 by The Journal of Bone and Joint Surgery, Incorporated.

  14. A study on aerosol-cloud condensation nuclei (CCN) activation over eastern Himalaya in India

    NASA Astrophysics Data System (ADS)

    Roy, Arindam; Chatterjee, Abhijit; Sarkar, Chirantan; Das, Sanat Kumar; Ghosh, Sanjay Kumar; Raha, Sibaji

    2017-06-01

    Simultaneous measurements of condensation nuclei (CN) and cloud condensation nuclei (CCN) has been performed over a high altitude site Darjeeling (27°01‧N, 88°15‧E, 2200 m asl) at eastern part of Himalaya in India. The study was carried out during dry seasons (October 2015-May 2016) to investigate the temporal variability of CN and CCN concentrations and the major factors controlling CN-CCN activation. CCN concentrations measured at 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8 and 0.9% super saturations have been reported in this study. The number concentrations of CN ranged between 694 and 23,643 cm- 3 with an average of 6563 ± 2160 cm- 3 whereas that of CCN (at 0.5% super saturation) ranged between 262 and 13,382 cm- 3 with an average of 1761 ± 856 cm- 3 during the entire study period. CN and CCN showed prominent monthly and seasonal variations controlled by local emissions, meteorological factors and long-range transport. Indo-Gangetic Plain (IGP) was found to be the most contributing region for CN and CCN over Darjeeling mainly during winter and premonsoon. A clear indication of the contribution of aerosols from plain land regions driven by up-slope valley wind was observed during premonsoon from diurnal variability of CN and CCN. Overall, 30-32% aerosols were observed to activate to CCN during winter and premonsoon whereas 24% activation was observed during postmonsoon. Chemical nature and hence solubility of aerosols controlled CCN activation more in night-time than day-time as observed from the correlations between activation ratios and hygroscopicity parameter, k. Strong seasonal dependence of CCN and activation ratio on super saturation and aerosol loading was observed. We observed higher CN and CCN loading and lower activation ratio over Darjeeling compared to western Himalayan high altitude station suggesting higher influence of local and long-range aerosols over eastern Himalaya and significant difference in chemical nature of aerosols between these two

  15. Cosmogenic nuclei

    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.

  16. Mental rotation of objects retrieved from memory: a functional MRI study of spatial processing.

    PubMed

    Just, M A; Carpenter, P A; Maguire, M; Diwadkar, V; McMains, S

    2001-09-01

    This functional MRI study examined how people mentally rotate a 3-dimensional object (an alarm clock) that is retrieved from memory and rotated according to a sequence of auditory instructions. We manipulated the geometric properties of the rotation, such as having successive rotation steps around a single axis versus alternating between 2 axes. The latter condition produced much more activation in several areas. Also, the activation in several areas increased with the number of rotation steps. During successive rotations around a single axis, the activation was similar for rotations in the picture plane and rotations in depth. The parietal (but not extrastriate) activation was similar to mental rotation of a visually presented object. The findings indicate that a large-scale cortical network computes different types of spatial information by dynamically drawing on each of its components to a differential, situation-specific degree.

  17. Isomer Studies for Nuclei near the Proton Drip Line in the Mass 130-160 Region

    SciTech Connect

    Cullen, D. M.; Mason, P. J. R.; Khan, S.; Kishada, A. M.; Varley, B. J.; Rigby, S. V.; Scholey, C.; Greenlees, P.; Rahkila, P.; Jones, P. M.; Julin, R.; Juutinen, S.; Leino, M.; Leppaenen, A. P.; Nyman, M.; Uusitalo, J.; Grahn, T.; Nieminen, P.; Pakarinen, J.

    2007-11-30

    This report details the status of an experimental research programme which has studied isomeric states in the mass 130-160 region of the nuclear chart. Several new isomers have been established and characterised near the proton drip line using a recoil isomer tagging technique at the University of Jyvaeskylae, Finland. The latest experiments have been performed with a modified setup where the standard GREAT focal-plane double-sided silicon-strip detector was changed to a dual multi-wire proportional-counter arrangement. This new setup has improved capability for short-lived isomer studies where high focal-plane rates can be tolerated. The results of key recent experiments for nuclei situated above ({sup 153}Yb,{sup 152}Tm) and below ({sup 136}Pm,{sup 142}Tb) the N = 82 shell gap were presented along with an interpretation for the isomers. Finally, the future prospects of the technique, using an isomer-tagged differential-plunger setup, were discussed. This technique will be capable of establishing the deformation of the states above the isomers and will aid in the process of assigning underlying single-particle configurations to the isomeric states.

  18. Studies of transitional Gadolinium nuclei by particle-gamma coincidence techniques

    NASA Astrophysics Data System (ADS)

    Ross, T. J.; Hughes, R. O.; Beausang, C. W.; Allmond, J. M.; Burke, J. T.; Escher, J. E.; Phair, L. W.; Scielzo, N.; 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.; Stars-Liberace Collaboration

    2011-10-01

    Nuclei in the N = 90 transitional region have been the focus of intense study for a number of years. In spite of this, recent particle-gamma coincidence studies of 155Gd revealed inconsistencies in the present single particle assignments. Expanding on these findings, an experiment was performed using the STARS-LIBERACE array at the 88-Inch Cyclotron in Lawrence Berkeley National Laboratory. A 25 MeV proton beam incident on 154Gd and 158Gd targets was used to populate states in 152 , 153 , 156 , 157Gd via (p,d) and (p,t) reactions. The silicon telescope STARS provided particle identification, residual nucleus energy and angular information. Coincident gamma rays were detected using the LIBERACE clover array. Details of new states identified in 153Gd and 157Gd will be presented as well as a method of extracting the spin distribution imparted to the nucleus via transfer reactions. This work supported in part by U.S. DOE grant numbers DE-FG02-05 ER41379 & DE-FG52-06 NA26206(University of Richmond), DE-AC52 07NA27344(LLNL) and DE-AC02 05CH11231(LBNL).

  19. Cloud condensation nuclei closure study on long-term observation data

    NASA Astrophysics Data System (ADS)

    Schmale, Julia; Henning, Silvia; Stratmann, Frank; Henzing, Bas; Kos, Gerard; Schlag, Patrick; Holzinger, Ruprecht; Aalto, Pasi; Keskinen, Helmi; Paramonov, Mikhail; Poulain, Laurent; Ovadnevaite, Jurgita; Krüger, Mira; Carbone, Samara; Brito, Joel; Fröhlich, Roman; Herrmann, Erik; Hammer, Emanuel; Baltensperger, Urs; Gysel, Martin

    2016-04-01

    Aerosol-cloud interactions (ACI) are currently the least understood influence on climate change (IPCC, 2013). ACI are largely controlled by the relative change in cloud condensation nuclei (CCN) and ice nuclei (IN) number concentrations. As direct CCN and IN measurements are not always at hand, being able to predict their concentrations is important. Focusing on CCN, we use monitoring type data from 5 stations within the ACTRIS network in Europe (http://www.actris.net/) and the ATTO site in Brazil to compare measured CCN concentrations at various supersaturations with predicted concentrations based on kappa-Köhler theory. The locations represent a variety of different environments including the rain and boreal forests, and continental-remote, marine and high-alpine conditions. At all sites, at least one full year of CCN concentrations, size distribution and chemical composition data were available for the period between 2012 and 2014. Submicron particle chemical composition data were provided by either Aerodyne aerosol mass spectrometers (AMS) or aerosol chemical speciation monitors (ACSM) and used to derive the hygroscopicity parameter kappa. We explore how well standard kappa-Köhler theory can be applied in the different environments. We find kappa ranging between 0.2 (median) for forest environments, 0.35 for continental-remote and high-alpine conditions, and 0.75 for the marine site. Generally, theory can predict actual CCN concentration within ± 25 % with relatively high correlation coefficients > 0.8 for all supersaturations and throughout all seasons. Applying a fixed kappa of 0.3 instead of hourly derived values yields similarly good results in most cases, while it leads to a discrepancy mismatch for the marine site and a slight difference for the rain forest aerosol. In addition, we find a number of mismatches that can be explained by data quality issues rather than deficiencies in the theory. A sensitivity study shows that only unrealistic assumptions

  20. The joint observation and study project for slowly rotating asteroids

    NASA Astrophysics Data System (ADS)

    Wang, Xiaobin; Muninonen, karri; Han, Xianming L.; Wang, Yibo

    2015-08-01

    The study for the spin rates and shapes of asteroids provides us important information to understand asteroids' structure and their physical processes. For example, a single Maxwellian distribution of the spin rates of larger asteroids (e.g. larger than 50km in diameter) reflects they had undergone collison history; a more dispersed distribution of smaller asteroids may be associated with the affect of radiation pressure torques( Pravec& Harris2000). Therefore, larger samples of spin parameters are needed for understanding deeply the evolution of asteroids. Meanwhile, some special subsets of asteroids, such as the slow rotators which probably represent a different physical process for asteroids, can open other windows to understand asteroids. Here we focus on a subset of larger asteroids with spin rates around 1 or 0.5 revolution per day. For these asteroids, the same rotational phases are observed repeatly by a telescope in different time. Under such cases, some ambigous spin periods are guessed, and it is impossible to determine their shapes. For determining the accurate spin parameters and shapes of these asteroids, a collaboration among several countries was established in 2014. Till now, the joint observations for a few of slow rotators have been made by several different telescopes distributed in China, USA and Chile. As samples, here we present new jiont observations in 2014 and analysis results for asteroids (346) Hermentaria and (168) Sibylla.Considering reasonable shapes of asteroids, the spin parameters of the two asteroids are analyzed carefully. Firstly, the procedure of analysis involves the MCMC method to find the initial spin parameters, which is based on a triaxial ellipsoid shape and a Lommel-Seeliger surface scattering law(Muinonen et al.2014). Then, the fine spin parameters accompanying with uncertainties and convex shapes of the asteroids are derived using the light curve inversion method(Kaasalainen et al 2002) and virtual photometric method

  1. Spectroastrometry of rotating gas disks for the detection of supermassive black holes in galactic nuclei. II. Application to the galaxy Centaurus A (NGC 5128)

    NASA Astrophysics Data System (ADS)

    Gnerucci, A.; Marconi, A.; Capetti, A.; Axon, D. J.; Robinson, A.; Neumayer, N.

    2011-12-01

    We measure the black hole mass in the nearby active galaxy Centaurus A (NGC 5128) using a new method based on spectroastrometry of a rotating gas disk. The spectroastrometric approach consists in measuring the photocenter position of emission lines for different velocity channels. In a previous paper we focused on the basic methodology and the advantages of the spectroastrometric approach with a detailed set of simulations demonstrating the possibilities for black hole mass measurements going below the conventional spatial resolution. In this paper we apply the spectroastrometric method to multiple longslit and integral field near infrared spectroscopic observations of Centaurus A. We find that the application of the spectroastrometric method provides results perfectly consistent with the more complex classical method based on rotation curves: the measured BH mass is nearly independent of the observational setup and spatial resolution and the spectroastrometric method allows the gas dynamics to be probed down to spatial scales of ~0.02″, i.e. 1/10 of the spatial resolution and ~1/50 of BH sphere of influence radius. The best estimate for the BH mass based on kinematics of the ionised gas is then log (MBH sin i2/M⊙) ≃ 7.5 ± 0.1 which corresponds to MBH= 9.6-1.8+2.5 × 107 M⊙ for an assumed disk inclination of i = 35°. The complementarity of this method with the classic rotation curve method will allow us to put constraints on the disk inclination which cannot be otherwise derived from spectroastrometry. With the application to Centaurus A, we have shown that spectroastrometry opens up the possibility of probing spatial scales smaller than the spatial resolution, extending the measured MBH range to new domains which are currently not accessible: smaller BHs in the local universe and similar BHs in more distant galaxies.

  2. Spectroastrometry of rotating gas disks for the detection of supermassive black holes in galactic nuclei. III. CRIRES observations of the Circinus galaxy

    NASA Astrophysics Data System (ADS)

    Gnerucci, A.; Marconi, A.; Capetti, A.; Axon, D. J.; Robinson, A.

    2013-01-01

    We present new CRIRES spectroscopic observations of the Brγ emission line in the nuclear region of the Circinus galaxy, obtained with the aim of measuring the black hole (BH) mass with the spectroastrometric technique. The Circinus galaxy is an ideal benchmark for the spectroastrometric technique given its proximity and secure BH measurement obtained with the observation of its nuclear H2O maser disk. The kinematical data have been analyzed both with the classical method based on the analysis of the rotation curves and with the new method developed by us that is based on spectroastrometry. The classical method indicates that the gas disk rotates in a gravitational potential resulting from an extended stellar mass distribution and a spatially unresolved dynamical mass of (1.7 ± 0.2) × 107 M⊙, concentrated within r < 7 pc, corresponding to the seeing-limited resolution of the observations. The new method is capable of probing the gas rotation at scales that are a factor ~3.5 smaller than those probed by the rotation curve analysis, highlighting the potential of spectroastrometry. The dynamical mass, which is spatially unresolved with the spectroastrometric method, is a factor ~2 smaller, 7.9+1.4-1.1 × 106M⊙, indicating that spectroastrometry has been able to spatially resolve the nuclear mass distribution down to 2 pc scales. This unresolved mass is still a factor ~4.5 larger than the BH mass measurement obtained with the H2O maser emission, indicating that even with spectroastrometry, it has not been possible to resolve the sphere of influence of the BH. Based on literature data, this spatially unresolved dynamical mass distribution is likely dominated by warm molecular gas and has been tentatively identified with the circum-nuclear torus that prevents a direct view of the central BH in Circinus. This mass distribution, with a size of ~2 pc, is similar in shape to that of the star cluster of the Milky Way, suggesting that a molecular torus, forming stars at

  3. Evidence for {open_quotes}magnetic rotation{close_quotes} in nuclei: New results on the M1-bands of {sup 198,199}Pb

    SciTech Connect

    Clark, R.M.

    1996-12-31

    Lifetimes of states in four of the M1-bands in {sup 198,199}Pb have been determined through a Doppler Shift Attenuation Method measurement performed using the Gammasphere array. The deduced B(M1) values, which are a sensitive probe of the underlying mechanism for generating these sequences, show remarkable agreement with Tilted Axis Cranking (TAC) calculations. Evidence is also presented for the possible termination of the bands. The results represent clear evidence for a new concept in nuclear excitations: {open_quote}magnetic rotation{close_quote}.

  4. Experimental and numerical studies of rotating drum grate furnace

    NASA Astrophysics Data System (ADS)

    Basista, Grzegorz; Szubel, Mateusz; Filipowicz, Mariusz; Tomczyk, Bartosz; Krakowiak, Joanna

    Waste material from the meat industry can be taken into account as a biofuel. Studies confirm, that calorific value is higher and ash content is lower comparing to some conventional fuels. EU directives regulate details of thermal disposal of the waste material from the meat industry - especially in range of the process temperature and time of the particle presence in area of the combustion zone. The paper describes design of the rotating drum grate stove, dedicated to thermal disposal of the meat wastes as well as solid biomass (pellet, small bricket, wood chips) combustion. Device has been developed in frames of cooperation between AGH University of Science and Technology (Krakow, Poland) and producer focused on technologies of energy utilization of biomass in distributed generation. Results of measurements of selected operational parameters performed during startup of the furnace have been presented and discussed. Furthermore, numerical model of the combustion process has been developed to complement experimental results in range of the temperature and oxygen distribution in the area of the combustion chamber. ANSYS CFX solver has been applied to perform simulations including rotational domain related with specifics of operation of the device. Results of numerical modelling and experimental studies have been summarized and compared.

  5. Experimental and numerical studies of rotating drum grate furnace

    NASA Astrophysics Data System (ADS)

    Basista, Grzegorz; Szubel, Mateusz; Filipowicz, Mariusz; Tomczyk, Bartosz; Krakowiak, Joanna

    2016-11-01

    Waste material from the meat industry can be taken into account as a biofuel. Studies confirm, that calorific value is higher and ash content is lower comparing to some conventional fuels. EU directives regulate details of thermal disposal of the waste material from the meat industry - especially in range of the process temperature and time of the particle presence in area of the combustion zone. The paper describes design of the rotating drum grate stove, dedicated to thermal disposal of the meat wastes as well as solid biomass (pellet, small bricket, wood chips) combustion. Device has been developed in frames of cooperation between AGH University of Science and Technology (Krakow, Poland) and producer focused on technologies of energy utilization of biomass in distributed generation. Results of measurements of selected operational parameters performed during startup of the furnace have been presented and discussed. Furthermore, numerical model of the combustion process has been developed to complement experimental results in range of the temperature and oxygen distribution in the area of the combustion chamber. ANSYS CFX solver has been applied to perform simulations including rotational domain related with specifics of operation of the device. Results of numerical modelling and experimental studies have been summarized and compared.

  6. Setup with Laser Ionization in Gas Cell for Production and Study of Neutron-Rich Heavy Nuclei

    NASA Astrophysics Data System (ADS)

    Zagrebaev, V. I.; Zemlyanoy, S. G.; Kozulin, E. M.; Kudryavtsev, Yu.; Fedosseev, V.; Bark, R.; Janas, Z.; Othman, H. A.

    2015-11-01

    The present limits of the upper part of the nuclear map are very close to stability while the unexplored area of heavy neutron-rich nuclides along the neutron closed shell N=126 is extremely important for nuclear astrophysics investigations and, in particular, for the understanding of the r-process of astrophysical nucleosynthesis. This area of the nuclear map can be reached neither in fusion-fission reactions nor in fragmentation processes widely used nowadays for the production of exotic nuclei. A new way was recently proposed for the production of these nuclei via low-energy multi-nucleon transfer reactions. The estimated yields of neutron-rich nuclei are found to be significantly high in such reactions and several tens of new nuclides can be produced, for example, in the near-barrier collision of 136Xe with 208Pb. A new setup is proposed to produce and study heavy neutron-rich nuclei located along the neutron closed shell N=126.

  7. Nuclear transplant studies on the reduction in numbers of presumptive germ nuclei in exconjugants of Paramecium caudatum.

    PubMed

    Mikami, K

    1982-08-01

    Nuclear differentiation in exconjugants of Paramecium caudatum is closely associated with a brief localization of the postzygotic nuclei near the opposite ends of the cell, with the germinal nucleus (micronucleus) in the anterior region and the somatic nuclei (macronuclei) in the posterior region. The posterior nuclei cannot regenerate to produce micronuclei when all four anterior nuclei are removed. There is no difference among the anterior four presumptive micronuclei, because, when any three of them were removed, the remaining nucleus was able to divide at each postconjugational fission and to persist as a micronucleus during the vegetative phase. This conclusion agrees with the results of transplanting a presumptive micronucleus into a vegetative cell. Cells during the vegetative phase, however, normally have only one micronucleus. Micronuclear number must be reduced to arrive at the uni-micronucleate condition after the stage of macro- and micronuclear differentiation. Elimination of supernumerary presumptive micronuclei, which had been indicated by morphological observations, was confirmed by the results of nuclear transplantation studies.

  8. Neuronal populations in the basolateral nuclei of the amygdala are differentially increased in humans compared with apes: a stereological study.

    PubMed

    Barger, Nicole; Stefanacci, Lisa; Schumann, Cynthia M; Sherwood, Chet C; Annese, Jacopo; Allman, John M; Buckwalter, Joseph A; Hof, Patrick R; Semendeferi, Katerina

    2012-09-01

    In human and nonhuman primates, the amygdala is known to play critical roles in emotional and social behavior. Anatomically, individual amygdaloid nuclei are connected with many neural systems that are either differentially expanded or conserved over the course of primate evolution. To address amygdala evolution in humans and our closest living relatives, the apes, we used design-based stereological methods to obtain neuron counts for the amygdala and each of four major amygdaloid nuclei (the lateral, basal, accessory basal, and central nuclei) in humans, all great ape species, lesser apes, and one monkey species. Our goal was to determine whether there were significant differences in the number or percent of neurons distributed to individual nuclei among species. Additionally, regression analyses were performed on independent contrast data to determine whether any individual species deviated from allometric trends. There were two major findings. In humans, the lateral nucleus contained the highest number of neurons in the amygdala, whereas in apes the basal nucleus contained the highest number of neurons. Additionally, the human lateral nucleus contained 59% more neurons than predicted by allometric regressions on nonhuman primate data. Based on the largest sample ever analyzed in a comparative study of the hominoid amygdala, our findings suggest that an emphasis on the lateral nucleus is the main characteristic of amygdala specialization over the course of human evolution. Copyright © 2012 Wiley Periodicals, Inc.

  9. Comparative study on the song behavior and song control nuclei in male and female Mongolian larks (Melanocorypha mongolica).

    PubMed

    Zhang, Xuebo; Zeng, Shaoju; Zhang, Xinwen; Zuo, Mingxue

    2011-09-12

    Songbirds can produce a remarkable diversity of songs, which is well-characterized learned behavior that reflects the basic processes of language learning in humans. As song control nuclei governing song behavior has been identified, bird song provides an excellent model to address the relationship between brain areas and their controlling behavior. The Mongolian lark (Melanocorypha mongolica), a species of the Alaudidae family, is well known for its elaborate singing and ability to learn new songs, even in adulthood. Here, we studied the singing behavior and underlying neural structures of the Mongolian lark in both sexes. We found that the sizes of song bouts and song phrases (song repertoires) in male Mongolian larks are extremely large, and that each song repertoire or phrase has a complex structure, comprising several different syllables that seldom appear in other types of song bouts. In accordance with these complex songs, Mongolian lark song control nuclei are well developed and can be easily detected by Nissl staining. In contrast to male Mongolian larks, females were not observed to sing. However, they possess significant song control nuclei with abundant neural connectivity within them despite their small sizes compared with males. These data provide new evidence that help further clarify the mechanisms by which songbirds sing. Our results also have implications for the evolution of complex birdsongs and song control nuclei in oscine birds.

  10. Proton propagation in nuclei studied in the ( e , e prime p ) reaction

    SciTech Connect

    Garino, G.; Saber, M.; Segel, R.E. ); Geesaman, D.F.; Gilman, R.; Green, M.C.; Holt, R.J.; Schiffer, J.P.; Zeidman, B. ); Beise, E.J.; Dodson, G.W.; Hoibraten, S.; Pham, L.D.; Redwine, R.P.; Sapp, W.W.; Williamson, C.F.; Wood, S.A. ); Chant, N.S.; Roos, P.G. ); Silk, J.D. ); Deady, M. ); Maruyama, X.K. )

    1992-02-01

    Proton propagation in nuclei was studied using the ({ital e},{ital e}{prime}{ital p}) reaction in the quasifree region. The coincidence ({ital e},{ital e}{prime}{ital p}) cross sections were measured at an electron angle of 50.4{degree} and proton angles of 50.1{degree}, 58.2{degree}, 67.9{degree}, and 72.9{degree} for {sup 12}C, {sup 27}Al, {sup 58}Ni, and {sup 181}Ta targets at a beam energy of 779.5 MeV. The average outgoing proton energy was 180 MeV. The ratio of the ({ital e},{ital e}{prime}{ital p}) yield to the simultaneously measured ({ital e},{ital e}{prime}) yield was compared to that calculated in the plane-wave impulse approximation and an experimental transmission defined. These experimental transmissions are considerably larger (a factor of {similar to}2 for {sup 181}Ta) than those one would calculate from the free {ital N}-{ital N} cross sections folded into the nuclear density distribution. A new calculation that includes medium effects ({ital N}-{ital N} correlations, density dependence of the {ital N}-{ital N} cross sections and Pauli suppression) accounts for this increase.

  11. Estimated desert-dust ice nuclei profiles from polarization lidar: methodology and case studies

    NASA Astrophysics Data System (ADS)

    Mamouri, R. E.; Ansmann, A.

    2015-03-01

    A lidar method is presented that permits the estimation of height profiles of ice nuclei concentrations (INC) in desert dust layers. The polarization lidar technique is applied to separate dust and non-dust backscatter and extinction coefficients. The desert dust extinction coefficients σd are then converted to aerosol particle number concentrations APC280 which consider particles with radius > 280 nm only. By using profiles of APC280 and ambient temperature T along the laser beam, the profile of INC can be estimated within a factor of 3 by means of APC-T-INC parameterizations from the literature. The observed close relationship between σd at 500 nm and APC280 is of key importance for a successful INC retrieval. We studied this link by means of AERONET (Aerosol Robotic Network) sun/sky photometer observations at Morocco, Cabo Verde, Barbados, and Cyprus during desert dust outbreaks. The new INC retrieval method is applied to lidar observations of dust layers with the spaceborne lidar CALIOP (Cloud Aerosol Lidar with Orthogonal Polarization) during two overpasses over the EARLINET (European Aerosol Research Lidar Network) lidar site of the Cyprus University of Technology (CUT), Limassol (34.7° N, 33° E), Cyprus. The good agreement between the CALIOP and CUT lidar retrievals of σd, APC280, and INC profiles corroborates the potential of CALIOP to provide 3-D global desert dust APC280 and INC data sets.

  12. Multi-wavelength polarimetry: a powerful tool to study the physics of active galactic nuclei

    NASA Astrophysics Data System (ADS)

    Goosmann, R. W.

    2009-11-01

    Accreting supermassive black holes reside in a very complex environment and the inner structure and dynamics of active galactic nuclei (AGN) are not well understood yet. In this note, I point out the important role that multi-wavelength polarimetry can play in understanding AGN. In addition to spectroscopy, the measurement of the polarization percentage and position angle provides two more observables that are sensitive to the geometry and kinematics of emission and scattering regions. Furthermore, time-dependent polarimetry allows to measure spatial distances between emission regions and scattering mirrors by applying a reverberation technique. For radiation coming from the direct vicinity of the black hole, the polarization also contains information about the space-time metric. Spectropolarimetry observations of AGN are obtained in the radio, the infrared, the optical, and the ultraviolet wave bands and in the future they are going be available also in the X-ray range. To interpret these observations in a coherent way, it is necessary to study models that do not only reproduce the broad-band spectroscopy properties of AGN but also their multi-wavelength polarization signature. I present a first step towards such models for the case of radio-quiet AGN. The modeling reveals the optical/UV and X-ray polarization properties of the reprocessed radiation coming from the obscuring torus. The discussion about the implications of such models includes prospects for the up-coming technique of X-ray (spectro-)polarimetry.

  13. Nonaxial shapes of even–even lantanide and actinide nuclei in excited collective states

    SciTech Connect

    Nadirbekov, M. S. Bozarov, O. A.

    2016-07-15

    Quadrupole-type excited states of even–even nuclei are studied on the basis of arbitrary-triaxiality model. It is shown that the inclusion of high-order terms in the expansion of the rotational-energy operator in the variable γ improves substantially agreement between our theoretical results and respective experimental data. The proposed model makes it possible to explain the intricate character of the spectrum of excited states of even–even lanthanide and actinide nuclei.

  14. In-beam studies of high-spin states of actinide nuclei

    SciTech Connect

    Stoyer, M.A. . Nuclear Science Div. California Univ., Berkeley, CA . Dept. of Chemistry)

    1990-11-15

    High-spin states in the actinides have been studied using Coulomb- excitation, inelastic excitation reactions, and one-neutron transfer reactions. Experimental data are presented for states in {sup 232}U, {sup 233}U, {sup 234}U, {sup 235}U, {sup 238}Pu and {sup 239}Pu from a variety of reactions. Energy levels, moments-of-inertia, aligned angular momentum, Routhians, gamma-ray intensities, and cross-sections are presented for most cases. Additional spectroscopic information (magnetic moments, M{sub 1}/E{sub 2} mixing ratios, and g-factors) is presented for {sup 233}U. One- and two-neutron transfer reaction mechanisms and the possibility of band crossings (backbending) are discussed. A discussion of odd-A band fitting and Cranking calculations is presented to aid in the interpretation of rotational energy levels and alignment. In addition, several theoretical calculations of rotational populations for inelastic excitation and neutron transfer are compared to the data. Intratheory comparisons between the Sudden Approximation, Semi-Classical, and Alder-Winther-DeBoer methods are made. In connection with the theory development, the possible signature for the nuclear SQUID effect is discussed. 98 refs., 61 figs., 21 tabs.

  15. Search for and discovery of chiral symmetry in nuclei

    SciTech Connect

    Pasternak, A. A.

    2010-08-15

    Studies devoted to the discovery and investigation of chiral-symmetry breaking in nuclei are briefly reviewed. Unlike the case of molecules and the macrocosm, where chirality manifests itself in the spatial structure of objects, chirality in nuclei is connected with different relative orientation of valence-quasiparticle spins and the angular momentum of collective rotation of the triaxial core. Decisive arguments in favor of the existence of this effect are based on measurements of lifetimes of high-spin nuclear levels in the picosecond range by Doppler methods of {gamma} spectroscopy.

  16. 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.

  17. A formalism for cosmic ray propagation studies. [model based on continuity equation of multiply charged nuclei

    NASA Technical Reports Server (NTRS)

    Golden, R. L.; Badhwar, G. D.; Stephens, S. A.

    1975-01-01

    The continuity equation for cosmic ray propagation is used to derive a set of linear equations interrelating the fluxes of multiply charged nuclei as observed at any particular part of the galaxy. The derivation leads to model independent definitions for cosmic ray storage time, mean density of target nuclei and effective mass traversed. The set of equations form a common framework for comparisons of theories and observations. As an illustration, it is shown that there exists a large class of propagation models which give the same result as the exponential path length model. The formalism is shown to accommodate dynamic as well as equilibrium models of production and propagation.

  18. A formalism for cosmic ray propagation studies. [model based on continuity equation of multiply charged nuclei

    NASA Technical Reports Server (NTRS)

    Golden, R. L.; Badhwar, G. D.; Stephens, S. A.

    1975-01-01

    The continuity equation for cosmic ray propagation is used to derive a set of linear equations interrelating the fluxes of multiply charged nuclei as observed at any particular part of the galaxy. The derivation leads to model independent definitions for cosmic ray storage time, mean density of target nuclei and effective mass traversed. The set of equations form a common framework for comparisons of theories and observations. As an illustration, it is shown that there exists a large class of propagation models which give the same result as the exponential path length model. The formalism is shown to accommodate dynamic as well as equilibrium models of production and propagation.

  19. Selfconsistent calculations for hyperdeformed nuclei

    SciTech Connect

    Molique, H.; Dobaczewski, J.; Dudek, J.; Luo, W.D.

    1996-12-31

    Properties of the hyperdeformed nuclei in the A {approximately} 170 mass range are re-examined using the self-consistent Hartree-Fock method with the SOP parametrization. A comparison with the previous predictions that were based on a non-selfconsistent approach is made. The existence of the {open_quotes}hyper-deformed shell closures{close_quotes} at the proton and neutron numbers Z=70 and N=100 and their very weak dependence on the rotational frequency is suggested; the corresponding single-particle energy gaps are predicted to play a role similar to that of the Z=66 and N=86 gaps in the super-deformed nuclei of the A {approximately} 150 mass range. Selfconsistent calculations suggest also that the A {approximately} 170 hyperdeformed structures have neglegible mass asymmetry in their shapes. Very importantly for the experimental studies, both the fission barriers and the {open_quotes}inner{close_quotes} barriers (that separate the hyperdeformed structures from those with smaller deformations) are predicted to be relatively high, up to the factor of {approximately}2 higher than the corresponding ones in the {sup 152}Dy superdeformed nucleus used as a reference.

  20. A Low Frequency Study of Rotating Radio Transients

    NASA Astrophysics Data System (ADS)

    Meyers, B.; Tremblay, S. E.; Bhat, N. D. R.; Shannon, R. M.

    2016-07-01

    Rotating radio transients (RRATs) are neutron stars whose radio emission is typically detectable as sporadic emission (as opposed to periodic emission). This RRAT study will observe two RRATs (J0614-03, J0545-03) which have low to moderate dispersion measures and should be detectable with the MWA. Nominally, both RRATs should be within a single pointing, due to the increased field-of-view provided by the compact hex-tile core. Given our first concrete detection of the RRAT J2325-0530 with the recently implemented coherent beamformer, we expect that these sources will also be detectable. Observations below 300MHz of these RRATs have not been reported, thus the MWA provides an opportunity to perform the first low-frequency, high time resolution studies of these objects.

  1. Cloud Condensation Nuclei Measurements During the First Year of the ORACLES Study

    NASA Astrophysics Data System (ADS)

    Kacarab, M.; Howell, S. G.; Wood, R.; Redemann, J.; Nenes, A.

    2016-12-01

    Aerosols have significant impacts on air quality and climate. Their ability to scatter and absorb radiation and to act as cloud condensation nuclei (CCN) plays a very important role in the global climate. Biomass burning organic aerosol (BBOA) can drastically elevate the concentration of CCN in clouds, but the response in droplet number may be strongly suppressed (or even reversed) owing to low supersaturations that may develop from the strong competition of water vapor (Bougiatioti et al. 2016). Understanding and constraining the magnitude of droplet response to biomass burning plumes is an important component of the aerosol-cloud interaction problem. The southeastern Atlantic (SEA) cloud deck provides a unique opportunity to study these cloud-BBOA interactions for marine stratocumulus, as it is overlain by a large, optically thick biomass burning aerosol plume from Southern Africa during the burning season. The interaction between these biomass burning aerosols and the SEA cloud deck is being investigated in the NASA ObseRvations of Aerosols above Clouds and their intEractionS (ORACLES) study. The CCN activity of aerosol around the SEA cloud deck and associated biomass burning plume was evaluated during the first year of the ORACLES study with direct measurements of CCN concentration, aerosol size distribution and composition onboard the NASA P-3 aircraft during August and September of 2016. Here we present analysis of the observed CCN activity of the BBOA aerosol in and around the SEA cloud deck and its relationship to aerosol size, chemical composition, and plume mixing and aging. We also evaluate the predicted and observed droplet number sensitivity to the aerosol fluctuations and quantify, using the data, the drivers of droplet number variability (vertical velocity or aerosol properties) as a function of biomass burning plume characteristics.

  2. Airborne cloud condensation nuclei measurements during the 2006 Texas Air Quality Study

    NASA Astrophysics Data System (ADS)

    Asa-Awuku, Akua; Moore, Richard H.; Nenes, Athanasios; Bahreini, Roya; Holloway, John S.; Brock, Charles A.; Middlebrook, Ann M.; Ryerson, Thomas B.; Jimenez, Jose L.; Decarlo, Peter F.; Hecobian, Arsineh; Weber, Rodney J.; Stickel, Robert; Tanner, Dave J.; Huey, Lewis G.

    2011-06-01

    Airborne measurements of aerosol and cloud condensation nuclei (CCN) were conducted aboard the National Oceanic and Atmospheric Administration WP-3D platform during the 2006 Texas Air Quality Study/Gulf of Mexico Atmospheric Composition and Climate Study (TexAQS/GoMACCS). The measurements were conducted in regions influenced by industrial and urban sources. Observations show significant local variability of CCN activity (CCN/CN from 0.1 to 0.5 at s = 0.43%), while variability is less significant across regional scales (˜100 km × 100 km; CCN/CN is ˜0.1 at s = 0.43%). CCN activity can increase with increasing plume age and oxygenated organic fraction. CCN measurements are compared to predictions for a number of mixing state and composition assumptions. Mixing state assumptions that assumed internally mixed aerosol predict CCN concentrations well. Assuming organics are as hygroscopic as ammonium sulfate consistently overpredicted CCN concentrations. On average, the water-soluble organic carbon (WSOC) fraction is 60 ± 14% of the organic aerosol. We show that CCN closure can be significantly improved by incorporating knowledge of the WSOC fraction with a prescribed organic hygroscopicity parameter (κ = 0.16 or effective κ ˜ 0.3). This implies that the hygroscopicity of organic mass is primarily a function of the WSOC fraction. The overall aerosol hygroscopicity parameter varies between 0.08 and 0.88. Furthermore, droplet activation kinetics are variable and 60% of particles are smaller than the size characteristic of rapid droplet growth.

  3. Studies of neutron-rich nuclei using the CPT mass spectrometer at CARIBU

    NASA Astrophysics Data System (ADS)

    Chaudhuri, A.; Bertone, P. F.; Buchinger, F.; Caldwell, S.; Clark, J. A.; Crawford, J. E.; Deibel, C. M.; Gulick, S.; Lascar, D.; Levand, A. F.; Li, G.; Savard, G.; Segel, R. E.; Sharma, K. S.; Sternberg, M. G.; Sun, T.; Van Schelt, J.

    2011-09-01

    The nucleosynthetic path of the astrophysical r-process and the resulting elemental abundances depend on neutron-separation energies which can be determined from the masses of the nuclei along the r-process reaction path. Due to the current lack of experimental data, mass models are often used. The mass values provided by the mass models are often too imprecise or disagree with each other. Therefore, direct high-precision mass measurements of neutron-rich nuclei are necessary to provide input parameters to the calculations and help refine the mass models. The Californium Rare Isotope Breeder Upgrade (CARIBU) facility of Argonne National Laboratory will provide experiments with beams of short-lived neutron-rich nuclei. The Canadian Penning Trap (CPT) mass spectrometer has been relocated to the CARIBU low-energy beam line to extend measurements of the neutron-rich nuclei into the mostly unexplored region along the r-process path. This will allow precise mass measurements (~ 10 keV/c2) of more than a hundred very neutron-rich isotopes that have not previously been measured.

  4. Enhanced Raman spectroscopic study of rotational isomers on metal surfaces

    NASA Technical Reports Server (NTRS)

    Loo, B. H.; Lee, Y. G.; Frazier, D. O.

    1986-01-01

    Surfaced-enhanced Raman spectroscopy has been used to study rotational isomers of succinonitrile and N-methyl-thioacetamide on Cu and Ag surfaces. Both the gauche and trans conformers of succinonitrile are found to chemisorb on the metal surface. The doubly degenerate nu(C-triple bond-N) in the free molecules is removed when succinonitrile adsorbs on copper, which indicates that the two (C-triple bond-N) groups are no longer chemically equivalent. Both conformers are found to coordinate to the copper surface through the pi system of one of the two (C-triple bond-N) groups. In the case of N-methyl-thioacetamide, the population of the cis isomer is greatly increased on Cu and Ag surfaces. This is probably due to surface-induced cis-trans isomerization, in which the predominant trans isomer is converted to the cis isomer.

  5. Experimental study of icing accretion on a rotating conical spinner

    NASA Astrophysics Data System (ADS)

    Chen, Ningli; Ji, Honghu; Hu, Yaping; Wang, Jian; Cao, Guangzhou

    2015-12-01

    A reduced scale experiment has been conducted to investigate the icing accretion procedure on a rotating spinner of 60° cone angle. The experiment was carried out in a small scale ice wind tunnel with three different rotating speeds of the spinner. The experimental conditions were determined from the actual icing condition of the spinner of a turbofan engine by using the similarity theory, which considers the rotating effects. The ice thickness on the spinner was got from the image taken by the high speed camera, by image processing. The results of this investigation show that under the experimental condition, ice on the spinner's tip of three different rotating speeds are all glaze ice and about the same thick. However, on the downstream surface of the spinner, ice shape on the rotating spinner is different from that on the stationary spinner. It is uneven glaze ice on the stationary spinner while it is `particle ice' when the rotating speed is 8240 rpm and it is `needle ice' when the rotating speed is 15,200 rpm. The experiment also reveals that when the rotating speed is higher, the ice layer is thicker.

  6. Impacts of new particle formation on aerosol cloud condensation nuclei (CCN) activity in Shanghai: case study

    NASA Astrophysics Data System (ADS)

    Leng, C.; Zhang, Q.; Zhang, D.; Zhang, H.; Xu, C.; Li, X.; Kong, L.; Tao, J.; Cheng, T.; Zhang, R.; Chen, J.; Qiao, L.; Lou, S.; Wang, H.; Chen, C.

    2014-07-01

    New particle formation (NPF) events and their impacts on cloud condensation nuclei (CCN) were investigated using continuous measurements collected in urban Shanghai from 1 to 30 April 2012. During the campaign, NPF occurred in 8 out of the 30 days and enhanced CCN number concentration (NCCN) by a actor of 1.2-1.8, depending on supersaturation (SS). The NPF event on 3 April 2012 was chosen as an example to investigate the NPF influence on CCN activity. In this NPF event, secondary aerosols were produced continuously and increased PM2.5 mass concentration at a~rate of 4.33 μg cm-3 h-1, and the growth rate (GR) and formation rate (FR) were on average 5 nm h-1 and 0.36 cm-3 s-1, respectively. The newly formed particles grew quickly from nucleation mode (10-20 nm) into CCN size range. NCCN increased rapidly at SS of 0.4-1.0% but weakly at SS of 0.2%. Correspondingly, aerosol CCN activities (fractions of activated aerosol particles in total aerosols, NCCN / NCN) were significantly enhanced from 0.24-0.60 to 0.30-0.91 at SS of 0.2-1.0% due to the NPF. On the basis of the κ-Köhler theory, aerosol size distributions and chemical composition measured simultaneously were used to predict NCCN. There was a good agreement between the predicted and measured NCCN (R2 = 0.96, Npredicted / Nmeasured = 1.04). This study reveals that NPF exerts large impacts on aerosol particle abundance and size spectra, thus significantly promotes NCCN and aerosol CCN activity in this urban environment. The GR of NPF is the key factor controlling the newly formed particles to become CCN at all SS levels, whereas the FR is an effective factor only under high SS (e.g. 1.0%) conditions.

  7. Studies of rotating liquid floating zones on Skylab IV

    NASA Technical Reports Server (NTRS)

    Carruthers, J. R.; Gibson, E. G.; Klett, M. G.; Facemire, B. R.

    1975-01-01

    Liquid zones of water, soap solution and soap foam were deployed between two aligned circular disks which were free to rotate about the zone axis in the microgravity environment of Skylab IV. Such a configuration is of interest in the containerless handling of melts for possible future space processing crystal growth experiments. Three basic types of zone surface deformation and instability were observed for these rotational conditions; axisymmetric shape changes under single disk rotation, nonaxisymmetric, whirling, C-modes for long zones with equal rotation of both disks, and capillary wave phenomena for short zones with equal rotation of both disks. The sources of these instabilities and the conditions promoting them are analyzed in detail from video tape recordings of the Skylab experiments.

  8. Morphologic studies of lymphocyte nuclei in follicular and diffuse mixed small- and large-cell (lymphocytic-histiocytic) lymphoma.

    PubMed

    Dardick, I; Caldwell, D R; Moher, D; Jabi, M

    1988-08-01

    Twelve examples of mixed small- and large-cell lymphoma (eight follicular, one follicular and diffuse, and three diffuse) were investigated morphometrically using plastic-embedded tissue in order to study nuclear characteristics of lymphocyte populations in this form of non-Hodgkin's lymphoma (NHL) and to test morphologic bases for current NHL classification systems. This study illustrates that there are many inaccuracies, illusions, and misconceptions in the morphologic criteria currently used to classify mixed small- and large-cell lymphoma. A principal finding was that lymphocyte nuclear profiles in mixed-cell lymphomas tend to be smaller in size (P less than .005) and more irregular in shape (P = .0001) than the morphologically similar counterparts in germinal centers of lymph nodes with reactive hyperplasia. Intercase comparison of mixed small- and large-cell lymphomas revealed a considerable range of mean nuclear area values, some of which were within the size range of normal, small lymphocytes. At the magnifications used for morphometric assessment, a high proportion of lymphocyte nuclear profiles had shallow invaginations, but only a limited number of profiles (4% to 14%) had deep (cleaved) indentations. Contrary to current definitions for this subtype of NHL, lymphocytes with "small" nuclei had the same proportion of the nuclear diameter occupied by nuclear invaginations as lymphocytes with "large" nuclei and, in fact, mean nuclear invagination depth was shallower in "small" nuclei than in "large" nuclei. Furthermore, regardless of whether it is nuclear area or shape that is evaluated, lymphocytes in mixed-cell lymphoma do not separate into two populations of small-cleaved and large noncleaved cells. Morphometry reveals that only four of the 12 examples of mixed small- and large-cell lymphoma had a proportion of the lymphocytes in the size range of fully transformed germinal center lymphocytes that exceeded 25%, and none of the cases approached 50% even

  9. Physics of Unstable Nuclei

    NASA Astrophysics Data System (ADS)

    Khoa, Dao Tien; Egelhof, Peter; Gales, Sydney; Giai, Nguyen Van; Motobayashi, Tohru

    2008-04-01

    Studies at the RIKEN RI beam factory / T. Motobayashi -- Dilute nuclear states / M. Freer -- Studies of exotic systems using transfer reactions at GANIL / D. Beaumel et al. -- First results from the Magnex large-acceptance spectrometer / A. Cunsolo et al. -- The ICHOR project and spin-isospin physics with unstable beams / H. Sakai -- Structure and low-lying states of the [symbol]He exotic nucleus via direct reactions on proton / V. Lapoux et al. -- Shell gap below [symbol]Sn based on the excited states in [symbol]Cd and [symbol]In / M. Górska -- Heavy neutron-rich nuclei produced in the fragmentation of a [symbol]Pb beam / Zs. Podolyák et al. -- Breakup and incomplete fusion in reactions of weakly-bound nuclei / D.J. Hinde et al. -- Excited states of [symbol]B and [symbol]He and their cluster aspect / Y. Kanada-En'yo et al. -- Nuclear reactions with weakly-bound systems: the treatment of the continuum / C. H. Dasso, A. Vitturi -- Dynamic evolution of three-body decaying resonances / A. S. Jensen et al. -- Prerainbow oscillations in [symbol]He scattering from the Hoyle state of [symbol]C and alpha particle condensation / S. Ohkubo, Y. Hirabayashi -- Angular dispersion behavior in heavy ion elastic scattering / Q. Wang et al. -- Microscopic optical potential in relativistic approach / Z.Yu. Ma et al. -- Exotic nuclei studied in direct reactions at low momentum transfer - recent results and future perspectives at fair / P. Egelhof -- Isotopic temperatures and symmetry energy in spectator fragmentation / M. De Napoli et al. -- Multi-channel algebraic scattering theory and the structure of exotic compound nuclei / K. Amos et al. -- Results for the first feasibility study for the EXL project at the experimental storage ring at GSI / N. Kalantar-Nayestanaki et al. -- Coulomb excitation of ISOLDE neutron-rich beams along the Z = 28 chain / P. Van Duppen -- The gamma decay of the pygmy resonance far from stability and the GDR at finite temperature / G. Benzoni et al

  10. Study of Nuclei far From Stability by Using the CHIMERA 4{pi} Detector and Radioactive Beams at LNS

    SciTech Connect

    Cardella, G.; De Filippo, E.; Pagano, A.; Papa, M.; Pirrone, S.; Verde, G.; Amorini, F.; Anzalone, A.; Maiolino, C.; Auditore, L.; Loria, D.; Trifiro, A.; Trimarchi, M.; Cavallaro, S.; Lombardo, I.; Porto, F.; Rizzo, F.; Russotto, P.; Chatterjee, M. B.; Geraci, E.

    2009-08-26

    At LNS are available radioactive beams at tandem and intermediate energies provided respectively by the EXCYT and by the fragmentation FRIBS facilities. Using these beams, and the 4{pi} detector CHIMERA, we want to study excitation and decay of resonances in light exotic nuclei populated with pick-up stripping and other reaction mechanisms. Some preliminary results obtained with stable and unstable beams are reported.

  11. Study of weakening of shell N = 28 for neutron rich nuclei through particle number fluctuation and pairing energy

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Rupayan

    2017-03-01

    Evolution of shells has been studied through fluctuations of particle numbers, pairing energies of large number of isotopes and isotones of nuclei evaluated through Skyrme-Hartree-Fock theory after inclusion of optimized tensor interaction. For neutron rich isotopes of Mg, Si, S and Ar no indication of shell closure at N = 28 has been observed. Calculations show occurrence of a doubly shell closed nucleus 114 Fl 184 .

  12. Signature effects in 2qp bands of doubly even rare-earth nuclei

    NASA Astrophysics Data System (ADS)

    Kalra, Kawalpreet; Goel, Alpana; Jain, A. K.

    2016-12-01

    The two-quasiparticle rotational bands in deformed doubly even nuclei in the rare-earth region have been studied in detail. A number of interesting features like odd-even staggering and signature inversion have been observed. The phenomenon of signature inversion/reversal is observed experimentally in 162 66Dy, 170 0Yb and 170 74W in even-even nuclei. Two quasiparticle plus rotor model (TQPRM) calculations are carried out to explain the reverse pattern of signature in 170 74W for the rotational band having configuration {(h_{11/2})p ⊗ (d_{5/2})p}.

  13. 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.

  14. Theoretical study of the similarity between nuclei with four valence nucleons in A = 208, 132 and 68 regions

    SciTech Connect

    Benmicia, N.; Benrachi, F.

    2012-06-27

    One of the most interesting topics in nuclear structure is the study of nuclei near the limits of particle stability. Much attention is currently being focused on nuclei with few valence nucleons around Z= 28, 50 and 82, in particular the 68Ni, 132Sn and 208Pb neighbors. We are interested of the even-even isobars 72Ni, 72Ge and 72Zn in 68Ni region, 136Sn, 136Xe and 136Te in 132Sn region, 212Pb, 212Rn and 212Po in 208Pb region. The calculation of energies spectra using the effective interactions JUN45M, CW{Delta}5082 and KHP shows a good agreement with the available experimental data for the energie levels and their sequences. We have extended the existed similarity between lead and tin regions to the Nickel region.

  15. Rotational study of the bimolecule acetic acid-fluoroacetic acid

    NASA Astrophysics Data System (ADS)

    Feng, Gang; Gou, Qian; Evangelisti, Luca; Caminati, Walther

    2017-01-01

    The rotational spectrum of the acetic acid-fluoroacetic acid bimolecule was measured by using a pulsed jet Fourier transform microwave spectrometer. One conformer, in which fluoroacetic acid is in trans form, has been observed. The rotational transitions are split into two component lines, due to the internal rotation of the methyl group of acetic acid. From these splittings, the corresponding V3 barrier has been determined. The dissociation energy of this complex has been estimated to 66 kJ/mol. An increase of the distance between the two monomers upon the OH → OD substitution (Ubbelohde effect) has been observed.

  16. A multi-frequency study of an X ray selected sample of active galactic nuclei

    NASA Astrophysics Data System (ADS)

    Grossan, Bruce Alan

    1992-01-01

    The LASS (Large Area Sky Survey) experiment, which flew aboard the HEAO-1 spacecraft, carried out a 2-20 keV survey of the sky during 1977-1978. The X-ray sources from this survey make up the LASS catalog (Wood et al. 1979). Optical counterparts have been identified for greater than 86 percent of the LASS sources above a flux of approx. 0.95 microns (mu)Jy Q 5 keV (Remillard 1992b). The LASS error boxes, along with the more precise positions from the Modulation Collimator (MC) X-ray experiment (also aboard HEAO-1), subsequent X-ray imaging, and optical search techniques were all used to identify the LASS sources. From these identifications, a high-latitude (absolute value of b greater than 20 deg.), flux limited (greater than or equal to 0.95 (mu)Jy) sample of 96 emission line Active Galactic Nuclei (AGN) have been selected for study. The sample is referred to as the LMA (for the LASS/MC identified sample of AGN). The objective of this work is to produce multi-frequency spectra of this sample of objects, in order to determine and interpret the statistical properties of the sample over nearly the full range of observable wavelengths. Data were obtained for as much of the radio through hard X-ray (less than 20 keV) spectrum as possible for each object in the LMA. Radio, near infrared, and other measurements were taken from the literature, far IR fluxes were extracted from co-added observations from IRAS, UV spectra were obtained from the IUE archives, and original observations were performed (with the help of collaborators) in the radio, near IR, optical, UV, and X-ray to fulfill this goal. Correlation studies of the continuum bands found poor correlations of X-ray and radio flux, good correlations for 12 and 26 micron flux with X-ray flux, excellent correlations for optical and near IR fluxes with X-rays, and poor correlations of UV and X-ray fluxes. Correlation studies of the line and X-ray continuum flux yield a good correlation between the flux of (OIII), the

  17. Cloud Condensation Nuclei in Cumulus Humilis - Selected Case Study During the CHAPS Campaign

    NASA Astrophysics Data System (ADS)

    Yu, X.; Berg, L. K.; Berkowitz, C. M.; Alexander, M. L.; Lee, Y.; Laskin, A.; Ogren, J. A.; Andrews, B.

    2009-12-01

    The Cumulus Humilis Aerosol Processing Study (CHAPS) provided a unique opportunity to study aerosol and cloud processing. Clouds play an active role in the processing and cycling of atmospheric constituents. Gases and particles can partition to cloud droplets by absorption and condensation as well as activation and pact scavenging. The Department of Energy (DOE) G-1 aircraft was used as one of the main platforms in CHAPS. Flight tracks were designed and implemented to characterize freshly emitted aerosols on cloud top and cloud base as well as with cloud, i.e., cumulus humilis (or fair-weather cumulus), in the vicinity of Oklahoma City. Measurements of interstitial aerosols and residuals of activated condensation cloud nuclei were conducted simultaneously. The interstitial aerosols were determined downstream of an isokinetic inlet; and the activated particles downstream of a counter-flow virtual impactor (CVI). The sampling line to the Aerodyne Aerosol Mass Spectrometer was switched between the isokinetic inlet and the CVI to allow characterization of interstitial particles out of clouds in contrast to particles activated in clouds. Trace gases including ozone, carbon monoxide, sulfur dioxide, and a series of volatile organic compounds (VOCs) were also measured as were key meteorological state parameters including liquid water content, cloud drop size, and dew point temperature were measured. This work will focus on studying CCN properties in cumulus humilis. Several approaches will be taken. The first is single particle analysis of particles collected by the Time-Resolved Aerosol Sampler (TRAC) by SEM/TEM coupled with EDX. We will specifically look into differences in particle properties such as chemical composition and morphology between activated and interstitial ones. The second analysis will link in situ measurements with the snap shots observations by TRAC. For instance, by looking into the characteristic m/z obtained by AMS vs. CO or isoprene, one can gain

  18. Studies of the shapes of heavy pear-shaped nuclei at ISOLDE

    NASA Astrophysics Data System (ADS)

    Butler, P. A.

    2016-07-01

    For certain combinations of protons and neutrons there is a theoretical expectation that the shape of nuclei can assume octupole deformation, which would give rise to reflection asymmetry or a "pear-shape" in the intrinsic frame, either dynamically (octupole vibrations) or statically (permanent octupole deformation). I will briefly review the historic evidence for reflection asymmetry in nuclei and describe how recent experiments carried out at REX-ISOLDE have constrained nuclear theory and how they contribute to tests of extensions of the Standard Model. I will also discuss future prospects for measuring nuclear shapes from Coulomb Excitation: experiments are being planned that will exploit beams from HIE-ISOLDE that are cooled in the TSR storage ring and injected into a solenoidal spectrometer similar to the HELIOS device developed at the Argonne National Laboratory.

  19. Studies of the shapes of heavy pear-shaped nuclei at ISOLDE

    SciTech Connect

    Butler, P. A.

    2016-07-07

    For certain combinations of protons and neutrons there is a theoretical expectation that the shape of nuclei can assume octupole deformation, which would give rise to reflection asymmetry or a ”pear-shape” in the intrinsic frame, either dynamically (octupole vibrations) or statically (permanent octupole deformation). I will briefly review the historic evidence for reflection asymmetry in nuclei and describe how recent experiments carried out at REX-ISOLDE have constrained nuclear theory and how they contribute to tests of extensions of the Standard Model. I will also discuss future prospects for measuring nuclear shapes from Coulomb Excitation: experiments are being planned that will exploit beams from HIE-ISOLDE that are cooled in the TSR storage ring and injected into a solenoidal spectrometer similar to the HELIOS device developed at the Argonne National Laboratory.

  20. Study of neutron-rich nuclei near doubly magic 132Sn

    NASA Astrophysics Data System (ADS)

    Sarkar, M. Saha; Sarkar, S.

    2012-06-01

    Large basis untruncated shell-model (SM) calculations have been done for nuclei with 50 ≤Z ≤56 and 82 ≤ N ≤ 88 in the π(gdsh) ⊗ ν (hf pi) valence space above the 132Sn core using both realistic CWG and empirical SMPN (1+2)-body Hamiltonians. These neutronrich nuclei lie on or close to the path of astrophysical r-process flow. Reasons behind the similarity and dissimilarity between the results using these two interactions have been discussed. The observation and prediction of unusually depressed first excited 2+1 states in even-A semi-magic Sn isotopes having N =84-88 and the possibility of a new magic number at N = 90 above 132Sn provide motivations for reviewing the problems related to the nuclear astrophysics in general.

  1. Study of near-stability nuclei populated as fission fragments in heavy-ion fusion reactions

    SciTech Connect

    Fotiadis, Nikolaos; Nelson, Ronald O; Devlin, Matthew; Cizewski, Jolie A; Krucken, Reiner; Clark, R M; Fallon, Paul; Lee, I Yang; Macchiavelli, Agusto O; Becker, John A; Younes, Walid

    2010-01-01

    Examples are presented to illustrate the power of prompt {gamma}-ray spectroscopy of fission fragments from compound nuclei with A {approx} 200 formed in fusion-evaporation reactions in experiments using the Gammasphere Ge-detector array. Complementary methods, such as Coulomb excitation and deep-inelastic processes, are also discussed. In other cases (n, xn{gamma}) reactions on stable isotopes have been used to establish neutron excitation functions for {gamma}-rays using a pulsed 'white'-neutron source, coupled to a high-energy-resolution germanium-detector array. The excitation functions can unambiguously assign {gamma}-rays to a specific reaction product. Results from all these methods bridge the gaps in the systematics of high-spin states between the neutron-deficient and neutron-rich nuclei. Results near shell closures should motivate new shell model calculations.

  2. The shapes of nuclei

    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.

  3. Radiations from hot nuclei

    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.

  4. Rotating Detonation Combustion: A Computational Study for Stationary Power Generation

    NASA Astrophysics Data System (ADS)

    Escobar, Sergio

    The increased availability of gaseous fossil fuels in The US has led to the substantial growth of stationary Gas Turbine (GT) usage for electrical power generation. In fact, from 2013 to 2104, out of the 11 Tera Watts-hour per day produced from fossil fuels, approximately 27% was generated through the combustion of natural gas in stationary GT. The thermodynamic efficiency for simple-cycle GT has increased from 20% to 40% during the last six decades, mainly due to research and development in the fields of combustion science, material science and machine design. However, additional improvements have become more costly and more difficult to obtain as technology is further refined. An alternative to improve GT thermal efficiency is the implementation of a combustion regime leading to pressure-gain; rather than pressure loss across the combustor. One concept being considered for such purpose is Rotating Detonation Combustion (RDC). RDC refers to a combustion regime in which a detonation wave propagates continuously in the azimuthal direction of a cylindrical annular chamber. In RDC, the fuel and oxidizer, injected from separated streams, are mixed near the injection plane and are then consumed by the detonation front traveling inside the annular gap of the combustion chamber. The detonation products then expand in the azimuthal and axial direction away from the detonation front and exit through the combustion chamber outlet. In the present study Computational Fluid Dynamics (CFD) is used to predict the performance of Rotating Detonation Combustion (RDC) at operating conditions relevant to GT applications. As part of this study, a modeling strategy for RDC simulations was developed. The validation of the model was performed using benchmark cases with different levels of complexity. First, 2D simulations of non-reactive shock tube and detonation tubes were performed. The numerical predictions that were obtained using different modeling parameters were compared with

  5. 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.

  6. Cloud Condensation Nuclei in Cumulus Humilis — selected Case Study During the CHAPS Campaign

    SciTech Connect

    Yu, X.; Lee, Y.; Berg, L.; Berkowitz, C.; Alexander, L.; Laskin, A.; Ogren, J.; Andrews, E.

    2010-03-15

    The Cumulus Humilis Aerosol Processing Study (CHAPS) provided a unique opportunity to study aerosol and cloud processing. Clouds play an active role in the processing and cycling of atmospheric constituents. Gases and particles can partition to cloud droplets by absorption and condensation as well as activation and impact scavenging. The U.S. Department of Energy (DOE) G-1 aircraft was used as one of the main platforms in CHAPS. Flight tracks were designed and implemented to characterize freshly emitted aerosols at cloud top and cloud base as well as within the cloud, i.e., cumulus humilis (or fair-weather cumulus), in the vicinity of Oklahoma City. Measurements of interstitial aerosols and residuals of activated condensation cloud nuclei were conducted simultaneously. The interstitial aerosols were measured downstream of an isokinetic inlet, and the activated particles downstream of a counter-flow virtual impactor (CVI). The sampling line to the Aerodyne Aerosol Mass Spectrometer (AMS) was switched between the isokinetic inlet and the CVI to allow characterization of non-activated interstitial particles outside of clouds in contrast to particles activated in clouds. Trace gases including ozone, carbon monoxide, sulfur dioxide, and a series of volatile organic compounds (VOCs) were also measured, as were key meteorological state parameters including liquid water content, cloud drop size, and dew point. We will report on the CCN properties in cumulus humilis. Several approaches will be taken. The first is single-particle analysis of particles collected by the Time-Resolved Aerosol Sampler (TRAC) by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) coupled with energy disperse X-ray spectroscopy (EDX). Specifically, we examine differences between activated and interstitial ones, such as differences in chemical composition and morphology. The second analysis will link in situ measurements by AMS and PTRMS with the observations by TRAC. For

  7. Conformational Studies of 1-OCTYNE from Rotational Spectroscopy

    NASA Astrophysics Data System (ADS)

    Maturo, Mark P.; Obenchain, Daniel A.; Melchreit, Robert; Cooke, S. A.; Novick, Stewart E.

    2017-06-01

    Alkanes of the form CH_3(CH_2)_nCH_3 generally favor ground state geometries that have co-planar carbon atoms. In this study, we have looked at a long chain hydrocarbon with a terminal carbon-carbon triple bond, viz., 1-octyne. Guided by the results of the 1-hexyne studies, three possible low energy conformers were studied which we reference as anti-anti (AA, straight chain), anti-gauche (AG, terminal methyl group is gauche), and gauche-anti (GA, ethyl group is gauche). An initial broadband chirp-pulse was performed between 7-13 GHz and a total of sixty-eight transitions were fit. Additional measurements on a Balle Flygare cavity instrument yielded an additional seventy-three lines belonging to three of the conformers. Transitions for all 8 of the singly substituted ^{13}C isotopologues, in natural abundance, have also been observed for the AA conformer. Ab-initio optimizations at the MP2/6-311++g(2d,2p) level of theory and basis set for these three conformers will be compared to experimental rotational constants. Structure determinations of the AA conformer will also be discussed. Atticks, K.; Bohn, R. K.; Michaels H. H. Int'l J. of Quantum Chem. 2001, 85, 514-519; Utzat, K.; Bohn, R. K.; Michaels H. H. J. Mol. Struct. 2007, 841, 22-27

  8. A study of human performance in a rotating environment

    NASA Technical Reports Server (NTRS)

    Green, J. A.; Peacock, J. L.; Holm, A. P.

    1971-01-01

    Consideration is given to the lack of sufficient data relative to the response of man to the attendant oculovestibular stimulations induced by multi-directional movement of an individual within the rotating environment to provide the required design criteria. This was done to determine the overall impact of artificial gravity simulations on potential design configurations and crew operational procedures. Gross locomotion and fine motor performance were evaluated. Results indicate that crew orientation, rotational rates, vehicle design configurations, and operational procedures may be used to reduce the severity of the adverse effects of the Coriolis and cross-coupled angular accelerations acting on masses moving within a rotating environment. Results further indicate that crew selection, motivation, and short-term exposures to the rotating environment may be important considerations for future crew indoctrination and training programs.

  9. A Study of volumetric variations of basal nuclei in the normal human brain by magnetic resonance imaging.

    PubMed

    Elkattan, Amal; Mahdy, Amal; Eltomey, Mohamed; Ismail, Radwa

    2017-03-01

    Knowledge of the effects of healthy aging on brain structures is necessary to identify abnormal changes due to diseases. Many studies have demonstrated age-related volume changes in the brain using MRI. 60 healthy individuals who had normal MRI aged from 20 years to 80 years were examined and classified into three groups: Group I: 21 persons; nine males and 12 females aging between 20-39 years old. Group II: 22 persons; 11 males and 11 females aging between 40-59 years old. Group III: 17 persons; eight males and nine females aging between 60-80 years old. Volumetric analysis was done to evaluate the effect of age, gender and hemispheric difference in the caudate and putamen by the slicer 4.3.3.1 software using 3D T1-weighted images. Data were analyzed by student's unpaired t test, ANOVA and regression analysis. The volumes of the measured and corrected caudate nuclei and putamen significantly decreased with aging in males. There was a statistically insignificant relation between the age and the volume of the measured caudate nuclei and putamen in females but there was a statistically significant relation between the age and the corrected caudate nuclei and putamen. There was no significant difference on the caudate and putamen volumes between males and females. There was no significant difference between the right and left caudate nuclei volumes. There was a leftward asymmetry in the putamen volumes. The results can be considered as a base to track individual changes with time (aging and CNS diseases). Clin. Anat. 30:175-182, 2017. © 2017 Wiley Periodicals, Inc.

  10. Cosmological Studies with Galaxy Clusters, Active Galactic Nuclei, and Strongly Lensed Quasars

    NASA Astrophysics Data System (ADS)

    Rumbaugh, Nicholas Andrew

    The large-scale structure (LSS) of the universe provides scientists with one of the best laboratories for studying Lambda Cold Dark Matter (LambdaCDM) cosmology. Especially at high redshift, we see increased rates of galaxy cluster and galaxy merging in LSS relative to the field, which is useful for studying the hierarchical merging predicted by LambdaCDM. The largest identified bound structures, superclusters, have not yet virialized. Despite the wide range of dynamical states of their constituent galaxies, groups, and clusters, they are all still actively evolving, providing an ideal laboratory in which to study cluster and galaxy evolution. In this dissertation, I present original research on several aspects of LSS and LambdaCDM cosmology. Three separate studies are included, each one focusing on a different aspect. In the first study, we use X-ray and optical observations from nine galaxy clusters at high redshift, some embedded in larger structures and some isolated, to study their evolutionary states. We extract X-ray gas temperatures and luminosities as well as optical velocity dispersions. These cluster properties are compared using low-redshift scaling relations. In addition, we employ several tests of substructure, using velocity histograms, Dressler-Shectman tests, and centroiding offsets. We conclude that two clusters out of our sample are most likely unrelaxed, and find support for deviations from self-similarity in the redshift evolution of the Lx-T relation. Our numerous complementary tests of the evolutionary state of clusters suggest potential under-estimations of systematic error in studies employing only a single such test. In the second study, we use multi-band imaging and spectroscopy to study active galactic nuclei (AGN) in high-redshift LSS. The AGN were identified using X-ray imaging and matched to optical catalogs that contained spectroscopic redshifts to identify members of the structures. AGN host galaxies tended to be associated with the

  11. Motor imagery in mental rotation: an fMRI study.

    PubMed

    Vingerhoets, Guy; de Lange, Floris P; Vandemaele, Pieter; Deblaere, Karel; Achten, Erik

    2002-11-01

    Twelve right-handed men performed two mental rotation tasks and two control tasks while whole-head functional magnetic resonance imaging was applied. Mental rotation tasks implied the comparison of different sorts of stimulus pairs, viz. pictures of hands and pictures of tools, which were either identical or mirror images and which were rotated in the plane of the picture. Control tasks were equal except that stimuli pairs were not rotated. Reaction time profiles were consistent with those found in previous research. Imaging data replicate classic areas of activation in mental rotation for hands and tools (bilateral superior parietal lobule and visual extrastriate cortex) but show an important difference in premotor area activation: pairs of hands engender bilateral premotor activation while pairs of tools elicit only left premotor brain activation. The results suggest that participants imagined moving both their hands in the hand condition, while imagining manipulating objects with their hand of preference (right hand) in the tool condition. The covert actions of motor imagery appear to mimic the "natural way" in which a person would manipulate the object in reality, and the activation of cortical regions during mental rotation seems at least in part determined by an intrinsic process that depends on the afforded actions elicited by the kind of stimuli presented.

  12. A study of rotational velocity distribution of Be stars

    NASA Astrophysics Data System (ADS)

    Sitko, C.; Janot-Pacheco, E.; Emilio, M.

    2014-10-01

    Classical Be stars are rapid rotators of spectral type late O to early A and luminosity class V-III, which exhibit Balmer emission lines and often a near infrared excess originating in an equatorially concentrated circumstellar envelope, both produced by sporadic mass ejection episodes. The causes of the abnormal mass loss (the so-called Be phenomenon) are as yet unknown. In spite of their high vsin i, rapid rotation alone cannot explain the ejection episodes as most Be stars do not rotate at their critical rotation rates. In this work we present the distribution of vsin i of 261 Be's stars from BeSS (Be Star Spectra) database. We used two techniques, the Fourier method and the FWHM (Full Width at Half Maximum) method. For the analysis we made use of three absorption lines of Helium (4026r A, 4388 Å and 4471 Å). Stars with projected rotational velocities up to 300 km s^{-1} agree with the ones already published in the literature. 84 of our stars do not have the values of rotational velocity published. The majority of our sample are B1/B2 spectral type, whose have the greatest velocities.

  13. Organization of the trigeminal and facial motor nuclei in the hagfish, Eptatretus burgeri: a retrograde HRP study.

    PubMed

    Kishida, R; Onishi, H; Nishizawa, H; Kadota, T; Goris, R C; Kusunoki, T

    1986-10-22

    We studied the trigeminal and facial motor nuclei of the hagfish by the retrograde HRP method. We distinguished 4 components in a single column of the motor nuclei of the trigeminal nerve and the facial nerve, viz., the pars magnocellularis of the trigeminal motor nucleus (mVm), the anterior part of the pars parvocellularis of the trigeminal motor nucleus (mVp1), the posterior part of the pars parvocellularis of the trigeminal motor nucleus (mVp2) and the facial motor nucleus (mVII). Although in Nissl preparations only the mVm could be distinguished from the rest of the nucleus, the boundaries of the other 3 components were clearly demarcated in HRP preparations. Intramuscular injections into two representative antagonistic jaw muscles revealed that there was no apparent topological organization of the neurons pertaining to the opening and closing muscles in the mVm and mVp1, but both antagonistic muscles were innervated bilaterally. Although the hagfish does possess a cartilaginous jaw, the organization pattern of the motor nuclei of the jaw muscles seems to be the most primitive of all living vertebrates.

  14. Search for Superheavy Nuclei

    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.

  15. Studies of ice nuclei at the Leipzig Aerosol Cloud Interaction Simulator and their implications

    NASA Astrophysics Data System (ADS)

    Wex, Heike

    2013-04-01

    Ice containing clouds permanently cover 40% of the earth's surface. Ice formation processes have a large impact on the formation of precipitation, cloud radiative properties, cloud electrification and hence influence both, weather and climate. Our understanding of the physical and chemical processes underlying ice formation is limited. However what we know is that the two main pathways of atmospheric ice formation are homogeneous and heterogeneous ice nucleation. The latter involves aerosol particles that act as ice nuclei inducing cloud droplet freezing at temperatures significantly above the homogeneous freezing threshold temperature. Particles acting as IN are e.g. dust particles, but also biological particles like bacteria, pollen and fungal spores. Different heterogeneous freezing mechanisms do exit, with their relative importance for atmospheric clouds still being debated. However, there are strong indications that immersion freezing is the most important mechanism when considering mixed phase clouds. What we are still lacking is a) the fundamental process understanding on how aerosol particles induce ice nucleation and b) means to quantify ice nucleation in atmospheric models. Concerning a) there most likely is not only one answer, considering the variety of IN found in the atmosphere. With respect to b) different approaches based on either the stochastic or singular hypotheses have been suggested. However it is still being debated which would be a suitable way to parameterize laboratory data for use in atmospheric modeling. In this presentation, both topics will be addressed. Using the Leipzig Aerosol Cloud Interaction Simulator (LACIS) (Hartmann et al., 2011), we examined different types of dust particles with and without coating, and biological particles such as bacteria and pollen, with respect to their immersion freezing behaviour. We will summarize our findings concerning the properties controlling the ice nucleation behaviour of these particles and

  16. Studies of superconducting materials with muon spin rotation

    NASA Technical Reports Server (NTRS)

    Davis, Michael R.; Stronach, Carey E.; Kossler, W. J.; Schone, H. E.; Yu, X. H.; Uemura, Y. J.; Sternlieb, B. J.; Kempton, J. R.; Oostens, J.; Lankford, W. F.

    1989-01-01

    The muon spin rotation/relaxation technique was found to be an exceptionally effective means of measuring the magnetic properties of superconductors, including the new high temperature superconductor materials, at the microscopic level. The technique directly measures the magnetic penetration depth (type II superconductors (SC's)) and detects the presence of magnetic ordering (antiferromagnetism or spin-glass ordering were observed in some high temperature superconductor (HTSC's) and in many closely related compounds). Extensive studies of HTSC materials were conducted by the Virginia State University - College of William and Mary - Columbia University collaboration at Brookhaven National Laboratory and TRIUMF (Vancouver). A survey of LaSrCuO and YBaCaCuO systems shows an essentially linear relationship between the transition temperature T(sub c) and the relaxation rate. This appears to be a manifestation of the proportionality between T(sub c) and the Fermi energy, which suggests a high energy scale for the SC coupling, and which is not consistent with the weak coupling of phonon-mediated SC. Studies of LaCuO and YBaCuO parent compounds show clear evidence of antiferromagnetism. YBa2Cu(3-x)CO(x)O7 shows the simultaneous presence of spin-glass magnetic ordering and superconductivity. Three-dimensional SC, (Ba, K) BiO3, unlike the layered CuO-based compounds, shows no suggestion of magnetic ordering. Experimental techniques and theoretical implications are discussed.

  17. Bands and Isomers in Neutron-Rich Rare-Earth Nuclei in PHF Model

    NASA Astrophysics Data System (ADS)

    Praharaj, C. R.; Ghorui, S. K.; Naik, Z.; Sahu, B. B.

    Rotational structures of neutron-rich Gd and Dy nuclei in the REE peak region are studied with deformed Hartee-Fock (HF) and angular momentum (J) projection model. Spectra of ground band and a few more excited, positive and negative parity bands have been studied up to high spin values. Some 4-quasiparticle K-isomeric bands and their electromagnetic properties are predicted.

  18. A study of solidification with a rotating magnetic field

    NASA Astrophysics Data System (ADS)

    Roplekar, Jayant K.

    Due to the drive for weight reduction in the automobile industry, near net shape parts produced by semi-solid processing of aluminum alloys are increasingly replacing traditional steel parts. Magnetohydrodynamic direct chill casting (MHD-DC) process, developed in the mid-eighties, is the method of choice to produce rheocast metal alloys for semi-solid applications. In spite of commercial applicability of the MHD-DC process there is no integrated process model available for this process. In the present work we use an experimental setup that combines directional solidification with magnetic stirring to develop a numerical model for the MHD-DC process. We use the finite element method to solve the coupled equations of turbulent fluid flow, species transport and heat transfer with solidification on a fixed grid. Effects of the rotating magnetic field are incorporated through a body-force term which is determined a priori based on a detailed analytical study and experimental data. Due to the nature of temperature-solute coupling and the advection dominated evolution of the liquid fraction, special numerical procedures had to be implemented in the present work. The numerical procedure used in the present work is validated against two validation problems. In the first validation problem, we apply the two-phase methodology to solve the classical problem of diffusion-dominated solidification. The good agreement between the finite element solution and the analytical solution establishes soundness of the two-phase formulation developed in this work. In the second validation problem, a finite element prediction of the flow induced in a cylindrical cavity due to a rotating magnetic field is compared with an independent spectral solution. The close agreement between two radically different solution procedures establishes the accuracy in the formulation and implementation of the both procedures. We then simulate the experiments using the numerical model. The numerical model

  19. The study of structure in 224-234 thorium nuclei within the framework IBM

    NASA Astrophysics Data System (ADS)

    Lee, Su Youn; Lee, Young Jun; Lee, J. H.

    2017-09-01

    An investigation has been made of the behaviour of nuclear structure as a function of an increase in neutron number from 224Th to 234Th. Thorium of mass number 234 is a typical rotor nucleus that can be explained by the SU(3) limit of the interacting boson model(IBM) in the algebraic nuclear model. Furthermore, 224-232Th lie on the path of the symmetry-breaking phase transition. Moreover, the nuclear structure of 224Th can be explained using X(5) symmetry. However, as 226-230Th nuclei are not fully symmetrical nuclei, they can be represented by adding a perturbed term to express symmetry breaking. Through the following three calculation steps, we identified the tendency of change in nuclear structure. Firstly, the structure of 232Th is described using the matrix elements of the Hamiltonian and the electric quadrupole operator between basis states of the SU(3) limit in IBM. Secondly, the low-lying energy levels and E2 transition ratios corresponding to the observable physical values are calculated by adding a perturbed term with the first-order Casimir operator of the U(5) limit to the SU(3) Hamiltonian in IBM. We compared the results with experimental data of 224-234Th. Lastly, the potential of the Bohr Hamiltonian is represented by a harmonic oscillator, as a result of which the structure of 224-234Th could be expressed in closed form by an approximate separation of variables. The results of these theoretical predictions clarify nuclear structure changes in Thorium nuclei over mass numbers of practical significance.

  20. Removal of residual nuclei following a cavitation event: a parametric study.

    PubMed

    Duryea, Alexander P; Tamaddoni, Hedieh A; Cain, Charles A; Roberts, William W; Hall, Timothy L

    2015-09-01

    The efficacy of ultrasound therapies such as hock-wave lithotripsy and histotripsy can be compromised by residual cavitation bubble nuclei that persist following the collapse of primary cavitation. In our previous work, we have developed a unique strategy for mitigating the effects of these residual bubbles using low-amplitude ultrasound pulses to stimulate their aggregation and subsequent coalescence—effectively removing them from the field. Here, we further develop this bubble removal strategy through an investigation of the effect of frequency on the consolidation process. Bubble removal pulses ranging from 0.5 to 2 MHz were used to sonicate the population of residual nuclei produced upon collapse of a histotripsy bubble cloud. For each frequency, mechanical index(MI) values ranging from 0 to approximately 1.5 were tested.Results indicated that, when evaluated as a function of bubble removal pulse MI, the efficacy of bubble removal shows markedly similar trends for all frequencies tested. This behavior divides into three distinct regimes (with provided cutoffs being approximate): 1) MI < 0.2: Minimal effect on the population of remanent cavitation nuclei; 2) 0.2 < MI < 1: Aggregation and subsequent coalescence of residual bubbles, the extent of which trends toward a maximum; and 3) MI > 1: Bubble coalescence is compromised as bubble removal pulses induce high-magnitude inertial cavitation of residual bubbles. The major distinction in these trends came for bubble removal pulses applied at 2 MHz, which were observed to generate the most effective bubble coalescence of all frequencies tested. We hypothesize that this is a consequence of the secondary Bjerknes force being the major facilitator of the consolidation process, the magnitude of which increases when the bubble size distribution is far from resonance such that the phase difference of oscillation of individual bubbles is minimal.

  1. Removal of Residual Nuclei Following a Cavitation Event: A Parametric Study

    PubMed Central

    Duryea, Alexander P.; Tamaddoni, Hedieh A.; Cain, Charles A.; Roberts, William W.; Hall, Timothy L.

    2015-01-01

    The efficacy of ultrasound therapies such as shock wave lithotripsy and histotripsy can be compromised by residual cavitation bubble nuclei that persist following the collapse of primary cavitation. In our previous work, we have developed a unique strategy for mitigating the effects of these residual bubbles using low amplitude ultrasound pulses to stimulate their aggregation and subsequent coalescence—effectively removing them from the field. Here, we further develop this bubble removal strategy through an investigation of the effect of frequency on the consolidation process. Bubble removal pulses ranging from 0.5 – 2 MHz were used to sonicate the population of residual nuclei produced upon collapse of a histotripsy bubble cloud. For each frequency, mechanical index (MI) values ranging from 0 to approximately 1.5 were tested. Results indicated that, when evaluated as a function of bubble removal pulse MI, the efficacy of bubble removal shows markedly similar trends for all frequencies tested. This behavior divides into three distinct regimes (with provided cutoffs being approximate): (1) MI < 0.2: Minimal effect on the population of remnant cavitation nuclei; (2) 0.2 < MI < 1: Aggregation and subsequent coalescence of residual bubbles, the extent of which trends toward a maximum; (3) MI > 1: Bubble coalescence is compromised as bubble removal pulses induce high magnitude inertial cavitation of residual bubbles. The major distinction in these trends came for bubble removal pulses applied at 2 MHz, which were observed to generate the most effective bubble coalescence of all frequencies tested. We hypothesize that this is a consequence of the secondary Bjerknes force being the major facilitator of the consolidation process, the magnitude of which increases when the bubble size distribution is far from resonance such that the phase difference of oscillation of individual bubbles is minimal. PMID:26719861

  2. Shell model Monte Carlo studies of nuclei in the A˜80 mass region

    NASA Astrophysics Data System (ADS)

    Langanke, K.; Dean, D. J.; Nazarewicz, W.

    2003-12-01

    We perform shell model Monte Carlo calculations for proton-rich Kr, Sr, and Zr isotopes in the mass range A=72-84. We employ a complete 1 p0 f-0 g1 d2 s configuration space and an effective quadrupole-plus-pairing residual interaction. Our calculation reproduces the large B( E2) values observed in these nuclei. We relate these values to the gain in correlation energy obtained by moving nucleons across the N=40 subshell closure into g9/2 orbitals.

  3. Study of nuclei far from stability with AYE-Ball array

    SciTech Connect

    Carpenter, M.P.

    1996-11-01

    The coupling of a Compton-suppressed Ge (CsGe) detector array to a recoil mass separator (RMS) has seen limited use in the past due to the low efficiency for measuring recoil-{gamma} ray coincidences (< 0.1%). With the building of new generation recoil separators and gamma-ray arrays, a substantial increase in detection efficiency has been achieved. This allows for the opportunity to measure excited states in nuclei with cross-sections approaching 100 nb. In this paper, results from the coupling of a modest array of CsGe detectors (AYE-Ball) with a recoil separator (FMA) will be presented.

  4. β-decay studies of r-process nuclei at NSCL

    NASA Astrophysics Data System (ADS)

    Pereira, J.; Aprahamian, A.; Arndt, O.; Becerril, A.; Elliot, T.; Estrade, A.; Galaviz, D.; Hennrich, S.; Hosmer, P.; Schnorrenberger, L.; Kessler, R.; Kratz, K.-L.; Lorusso, G.; Mantica, P. F.; Matos, M.; Montes, F.; Pfeiffer, B.; Quinn, M.; Santi, P.; Schatz, H.; Schertz, F.; Smith, E.; Tomlin, B. E.; Walters, W. B.; Wöhr, A.

    2008-06-01

    Observed neutron-capture elemental abundances in metal-poor stars, along with ongoing analysis of the extremely metal-poor Eu-enriched sub-class provide new guidance for astrophysical models aimed at finding the r-process sites. The present paper emphasizes the importance of nuclear physics parameters entering in these models, particularly β-decay properties of neutron-rich nuclei. In this context, several r-process motivated β-decay experiments performed at the National Superconducting Cyclotron Laboratory (NSCL) are presented, including a summary of results and impact on model calculations.

  5. Properties of Hot Nuclei at Extreme Angular Momenta Studied by the GDR

    SciTech Connect

    Maj, Adam; Kmiecik, Maria; Schunck, Nicolas; Styczen, Jan

    2005-11-21

    Hot nuclei, from both heavy and light mass regions, were investigated at extreme angular momenta by means of the gamma decay of Giant Dipole Resonance. It was found that the 216Rn nucleus possesses an almost spherical equilibrium shape up to the fission limit, while 46Ti undergoes a Jacobi shape transition. Preferential feeding of the highly deformed band in 42Ca by the low energy GDR component in 46Ti is found. The experimental results are interpreted within the newest liquid drop model LSD.

  6. Exotic atomic nuclei

    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.

  7. 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)

  8. Theoretical studies of rotational barriers of heteroatom derivatives of methanol

    SciTech Connect

    Wu, Yundong; Houk, K.N. )

    1990-06-14

    The rotational barrier about the C-O bond of methanol is well-known to be 1 kcal/mol. In this paper, the rotational barriers of heteroatom derivatives of methanol, CH{sub 3}OX, where X = F, Cl, O{sup {minus}}, OH, and OH{sub 2}{sup +}, are predicted to have the considerably higher values of 3.7, 3.5, 4.3, 3.3, and 3.5 kcal/mol, respectively, at the MP4/6-31G{sup **} basis set level, with staggered conformers being favored. These conformational preferences and rotational barriers are rationalized by a combination of antiperiplanar {sigma}{sub CH}-{sigma}{sup *}{sub OX} delocalization and {pi}-type orbital interactions between {pi}{sup *}{sub CH{sub 3}} and {pi}{sub -O-X} orbitals, both of which are maximized in the staggered conformation.

  9. A Study of 2-Iodobutane by Rotational Spectroscopy

    SciTech Connect

    Arsenault, Eric A.; Obenchain, Daniel A.; Choi, Yoon Jeong; Blake, Thomas A.; Cooke, S. A.; Novick, Stewart E.

    2016-09-15

    The rotational transitions belonging to 2-iodobutane (sec-butyl-iodide, CH3CHICH2CH3) have been measured over the frequency range 5.5-16.5 GHz via jet-pulsed Fourier transform microwave (FTMW) spectroscopy. The complete nuclear quadrupole coupling tensor of iodine, ¬, has been obtained for the gauche (g)-, anti (a)-, and gauche0 (g0)-conformers, as well as the four 13C isotopologues of the gauche species. Rotational constants, centrifugal distortion constants, quadrupole coupling constants, and nuclear spin-rotation constants were determined for each species. Changes in the ¬ of the iodine nucleus, resulting from conformational and isotopic dierences, will be discussed. Isotopic substitution of g-2-iodobutane allowed for a rs structure to be determined for the carbon backbone. Additionally, isotopic substitution, in conjunction with an ab initio structure, allowed for a t of various r0 structural parameters belonging to g-2-iodobutane.

  10. Otolith-Canal Convergence In Vestibular Nuclei Neurons

    NASA Technical Reports Server (NTRS)

    Dickman, J. David; Si, Xiao-Hong

    2002-01-01

    The current final report covers the period from June 1, 1999 to May 31, 2002. The primary objective of the investigation was to determine how information regarding head movements and head position relative to gravity is received and processed by central vestibular nuclei neurons in the brainstem. Specialized receptors in the vestibular labyrinths of the inner ear function to detect angular and linear accelerations of the head, with receptors located in the semicircular canals transducing rotational head movements and receptors located in the otolith organs transducing changes in head position relative to gravity or linear accelerations of the head. The information from these different receptors is then transmitted to central vestibular nuclei neurons which process the input signals, then project the appropriate output information to the eye, head, and body musculature motor neurons to control compensatory reflexes. Although a number of studies have reported on the responsiveness of vestibular nuclei neurons, it has not yet been possible to determine precisely how these cells combine the information from the different angular and linear acceleration receptors into a correct neural output signal. In the present project, rotational and linear motion stimuli were separately delivered while recording responses from vestibular nuclei neurons that were characterized according to direct input from the labyrinth and eye movement sensitivity. Responses from neurons receiving convergent input from the semicircular canals and otolith organs were quantified and compared to non-convergent neurons.

  11. Bacterial flagella rotating in bundles: a study in helical geometry.

    PubMed Central

    Macnab, R M

    1977-01-01

    Bacterial flagella are semi-rigid helices that undergo true rotation. In peritrichously flagellated bacteria (e.g., Escherichia and Salmonella) there are many flagella on each cell; during translational cell movement these operate as a coordinated bundle that actively disperses upon reversal of the rotation sense. The dynamic behavior of a set of helices originating on separate rotational axes is explored by a working model, geometrical analysis, and hydrodynamic calculations. A critical relationship exists between the interaxial separation and phase difference of parallel helices with overlapping domains; in the subcritical case the filaments are not intertwisted, whereas in the supercritical case they are intertwisted in the same sense (left-handed) as the helices, with one twist per helical turn. During counter-clockwise rotation (the sense operative in forward swimming) any preexisting twists of this kind are automatically cancelled and the helices brought progressively into phase. Hydrodynamic calculations suggest that some wrapping then occurs in a right-handed sense, opposite to that of the helices; this necessitates a distortion from true helical geometry which is minimized by maintaining a coaxial in-phase relationship. A highly coordinated helical bundle results that is capable of operating smoothly for an indefinite period, in agreement with the observed behavior of swimming bacteria. During reverse rotation, the supercritical case develops to cause jamming of the bundle, as has been observed with bacteria in high-viscosity medium. The explosive dispersal of the bundle during reversal in low-viscosity medium is a consequence of a complicating phenomenon, namely, a drastic change in flagellar quaternary structure. The overall conclusion is that bundle formation and function are perfectly compatible with a rotational mechanism for the individual flagella. Images PMID:264676

  12. Rotator cable: MRI study of its appearance in the intact rotator cuff with anatomic and histologic correlation.

    PubMed

    Gyftopoulos, Soterios; Bencardino, Jenny; Nevsky, Gregory; Hall, Gregory; Soofi, Yousef; Desai, Panna; Jazrawi, Laith; Recht, Michael P

    2013-05-01

    The purpose of this study was to define and correlate the appearance of the rotator cable on MRI with arthroscopy, band-saw cadaveric sections, and histology. Two cadaveric shoulders underwent 3-T MRI, band-sawing, and histologic evaluation. Three readers evaluated the MRI for the presence of the cable, and the same readers and a pathologist reviewed the macroscopic and microscopic specimens for a structure that corresponded to the cable. Cadaver 1 underwent arthroscopic evaluation to evaluate for the presence of a cable. Seventy consecutive shoulders that underwent 1.5- or 3-T MRI were also reviewed for the presence of the cable and evaluation of its characteristics (location, thickness, and width). A linear band of hypointense signal intensity was found along the undersurface of the supraspinatus and infraspinatus tendons on both cadaveric MR images, which correlated to a linear band of tissue in the same location on macroscopic and microscopic evaluation and linear thickening along the cuff articular surface on arthroscopy consistent with the cable. The cable was seen in 74.3% of the MRI studies in both sagittal and coronal planes with a mean (± SD) distance of the cable from the medial margin of the enthesis of 1.33 ± 0.27 cm, a mean width of the cable of 1.24 ± 0.31 cm, and a mean thickness of 0.19 ± 0.05 cm. The rotator cable is a structure that can be consistently seen on gross anatomic and histologic analysis, arthroscopy, and MRI in the intact rotator cuff. Familiarity with the typical location and morphology of the cable may allow easier characterization of disease that can involve the cable, such as rotator cuff tears.

  13. Spectroscopic study of the extremely fast rotating star 44 Geminorum

    NASA Astrophysics Data System (ADS)

    Iliev, L.; Vennes, S.; Kawka, A.; Kubat, J.; Nemeth, P.; Borisov, G.; KRaus, M.

    Stars with extremely fast rotation represent interesting challenge to modern understanding of the stellar evolution. The reasons why such a spin-up process should occur during the evolution to otherwise normal star are still not well understood. Already in the beginning of the XX century Otto Struve proposed that fast rotation of the group of stars spectroscopically classified as Be could be the main reason for the formation of observed disks of circumstellar material around them. This circumstellar material is responsible for the emission lines observed in the spectrum of Be-stars as well as for the whole complex of spectral and photometrical patterns called in general Be-phenomenon.

  14. Study of galactic rotation curves in wormhole spacetime

    NASA Astrophysics Data System (ADS)

    Rahaman, Farook; Sen, Banashree; Chakraborty, Koushik; Shit, G. C.

    2016-03-01

    The spacetime of the galactic halo region is described by a wormhole like line element. We assume violation of Null Energy Condition (NEC) in the galactic halo. The Einstein Field equations are solved for two different conditions of pressure and density to obtain physical parameters like tangential velocity of test particles and parameters related to the wormhole geometry. The theoretical rotation curve of the test particles is plotted and compared the same with an observed rotation curve. We obtain a satisfactory fit between the observed curve and the curve obtained from the present theory for the radial distances in the range 9 Kpc to 100 Kpc.

  15. Electron spin dynamics of Ce3 + ions in YAG crystals studied by pulse-EPR and pump-probe Faraday rotation

    NASA Astrophysics Data System (ADS)

    Azamat, D. V.; Belykh, V. V.; Yakovlev, D. R.; Fobbe, F.; Feng, D. H.; Evers, E.; Jastrabik, L.; Dejneka, A.; Bayer, M.

    2017-08-01

    The spin relaxation dynamics of Ce3 + ions in heavily cerium-doped YAG crystals is studied using pulse-electron paramagnetic resonance and time-resolved pump-probe Faraday rotation. Both techniques address the 4 f ground state, while pump-probe Faraday rotation also provides access to the excited 5 d state. We measure a millisecond spin-lattice relaxation time T1, a microsecond spin coherence time T2, and a ˜10 ns inhomogeneous spin dephasing time T2* for the Ce3 + ground state at low temperatures. The spin-lattice relaxation of Ce3 + ions is due to modified Raman processes involving the optical phonon mode at ˜125 cm-1 . The relaxation at higher temperature goes through a first excited level of the 5/2 2F term at about ℏ ω ≈228 cm-1 . Effects provided by the hyperfine interaction of the Ce3 + with the 27Al nuclei are observed.

  16. Structure of A Equals 76 Nuclei and Fast-Timing Studies of the Rare-Earth Region

    NASA Astrophysics Data System (ADS)

    Cooper, Nathan Michael

    produce useful results. Such cases include estimation of total -gamma-decay widths of neutron resonances and -gamma-ray spectra following nuclear reactions. Of particular interest in modern research are so-called pygmy resonances which may be due, for example, to a neutron skin resonance or other exotic modes of excitation. Another topic of continued interest is that of double-beta decay and in particular the search for neutrinoless double-beta (0vbeta) decay. Conclusive observation of 0 vbeta decay would show that the neutrino is its own anti-particle, and evaluation of the neutrino mass could be performed if the matrix element of the decay were known. Constraining parameters of theoretical models using experimental data is of the utmost importance to these calculations. In this dissertation, the structure of A = 76 nuclei near stability, candidates for involvement in the hypothetical 0vbeta decay of 76Ge, is explored though seven experiments performed at the Darmstadt High-Intensity Photon Source, the High Intensity Gamma-Ray Source, and at the Wright Nuclear Structure Laboratory. Of particular concern is the analysis and interpretation of nuclear resonance fluorescence data on 76Se, 76Ge, and nuclei in general. Details and results of experiments performed using fast-timing electronics to study structure of low-lying states of 174W and 176Hf at WNSL are additionally presented as an appendix.

  17. Unifying Spectral and Timing Studies of Relativistic Reflection in Active Galactic Nuclei

    NASA Astrophysics Data System (ADS)

    Reynolds, Christopher

    X-ray observations of active galactic nuclei (AGN) contain a wealth of information relevant for understanding the structure of AGN, the process of accretion, and the gravitational physics of supermassive black holes. A particularly exciting development over the past four years has been the discovery and subsequent characterization of time delays between variability of the X-ray power-law continuum and the inner disk reflection spectrum including the broad iron line. The fact that the broad iron line shows this echo, or reverberation, in XMM-Newton, Suzaku and NuSTAR data is a strong confirmation of the disk reflection paradigm and has already been used to place constraints on the extent and geometry of the X-ray corona. However, current studies of AGN X-ray variability, including broad iron line reverberation, are only scratching the surface of the available data. At the present time, essentially all studies conduct temporal analyzes in a manner that is largely divorced from detailed spectroscopy - consistency between timing results (e.g., conclusions regarding the location of the primary X-ray source) and detailed spectral fits is examined after the fact. We propose to develop and apply new analysis tools for conducting a truly unified spectraltiming analysis of the X-ray properties of AGN. Operationally, this can be thought of as spectral fitting except with additional parameters that are accessing the temporal properties of the dataset. Our first set of tools will be based on Fourier techniques (via the construction and fitting of the energy- and frequency-dependent cross-spectrum) and most readily applicable to long observations of AGN with XMM-Newton. Later, we shall develop more general schemes (of a more Bayesian nature) that can operate on irregularly sampled data or quasi-simultaneous data from multiple instruments. These shall be applied to the long joint XMM-Newton/NuSTAR and Suzaku/NuSTAR AGN campaigns as well as Swift monitoring campaigns. Another

  18. Broad-band study of hard X-ray-selected absorbed active galactic nuclei

    NASA Astrophysics Data System (ADS)

    de Rosa, A.; Panessa, F.; Bassani, L.; Bazzano, A.; Bird, A.; Landi, R.; Malizia, A.; Molina, M.; Ubertini, P.

    2012-03-01

    In this paper we report on the broad-band X-ray properties of a complete sample of absorbed Seyfert galaxies hard X-ray selected with INTEGRAL. Our sample is composed of 33 sources, of which 15 are newly discovered active galactic nuclei (AGN) above 20 keV (IGR sources), while 18 are already known type 2 AGN ('known'). For 17 sources (15 IGR + 2 'known' sources) we have performed a broad-band analysis using both XMM-Newton, and INTEGRAL-IBIS data. To have a full view of the complete sample we have then complemented the analysis of the 16 remaining sources with already existing broad-band studies in the same range. The high-quality broad-band spectra are well reproduced with an absorbed primary emission with a high-energy cut-off and its scattered fraction below 2-3 keV, plus the Compton reflection features (Compton hump and Fe line emission). This study permitted a very good characterization of the primary continuum and, in turn, of all the spectral features. A high-energy cut-off is found in 30 per cent of the sample, with an average value below 150 keV, suggesting that this feature has to be present in the X-ray spectra of obscured AGN. The hard X-ray selection favours the detection of more obscured sources, with the log NH average value of 23.15 (standard deviation of 0.89). The diagnostic plot NH versus Foss(2-10 keV)/F(20-100 keV) allowed the isolation of the Compton-thick objects, and may represent a useful tool for future hard X-ray observations of newly discovered AGN. We are unable to associate the reflection components (both continuum and Fe line) with the absorbing gas as a torus (as envisaged in the Unified Model), a more complex scenario being necessary. In the Compton-thin sources, a fraction (but not all) of the Fe K line needs to be produced in a gas located closer to the black hole than the Compton-thick torus, and this is possibly associated with the optical broad-line region, responsible also for the absorption. We still need a Compton

  19. Ensemble spectral variability study of Active Galactic Nuclei from the XMM-Newton serendipitous source catalogue

    NASA Astrophysics Data System (ADS)

    Serafinelli, R.; Vagnetti, F.; Middei, R.

    2016-02-01

    The variability of the X-Ray spectra of active galactic nuclei (AGN) usually includes a change of the spectral slope. This has been investigated for a small sample of local AGNs by Sobolewska and Papadakis [1], who found that slope variations are well correlated with flux variations, and that the spectra are typically steeper in the bright phase (softer when brighter behaviour). Not much information is available for the spectral variability of high-luminosity AGNs and quasars. In order to investigate this phenomenon, we use data from the XMM-Newton Serendipitous Source Catalogue, Data Release 5, which contains X- Ray observations for a large number of active galactic nuclei in a wide luminosity and redshift range, for several different epochs. This allows to perform an ensemble analysis of the spectral variability for a large sample of quasars. We quantify the spectral variability through the spectral variability parameter β, defined by Trevese and Vagnetti [2] as the ratio between the change in spectral slope and the corresponding logarithmic flux variation. We find that the spectral variability of quasars has a softer when brighter behaviour, similarly to local AGNs.

  20. Study of Electromagnetic Properties of Nuclei and Structural Changes at High Spins in Yb Isotopes

    NASA Astrophysics Data System (ADS)

    Mansour, N.; Awwad, Z.; Bayomy, T.; Diab, A.

    High-spin states of nuclei, populated by heavy-ion reactions, are of interest because they reveal changes in the structur of nuclei under stress. In the first part much of our insight into the structure of high-spin states is being provided by electromagnetic strength functions. In the second part, the level scheme of 158Yb has been extended to I = 37 by using the 98Mo (64Ni, 4n) reaction, and the backbending phenomena in Yb isotopes has been discussed.Translated AbstractUntersuchungen der elektromagnetischen Eigenschaften an Kernen von Yb-Isotopen und ihren Strukturänderungen bei hohem SpinDurch Schwerionenreaktionen erhaltene Kernzustände mit hohen Spinwerten sind von Interesse, weil sie Änderungen der Kernstruktur unter Beanspruchung aufzeigen. Ein Großteil unseres Verständnisses der Struktur dieser Zustände großen Spins resultiert aus den elektromagnetischen Feldstärkefunktionen. Wir erweitern das Zustandsschema von 158Yb bis zu I = 37 unter Benutzung der Reaktion 98Mo (64Ni, 4n) und diskutieren das Phänomen der Rückbiegung an Yb-Isotopen.

  1. Interaction of Fast Nucleons with Actinide Nuclei Studied with GEANT4

    NASA Astrophysics Data System (ADS)

    Malyshkin, Yu.; Pshenichnov, I.; Mishustin, I.; Greiner, W.

    2014-04-01

    We model interactions of protons and neutrons with energies from 1 to 1000 MeV with 241Am and 243Am nuclei. The calculations are performed with the Monte Carlo model for Accelerator Driven Systems (MCADS) which we developed based on the GEANT4 toolkit of version 9.4. This toolkit is widely used to simulate the propagation of particles in various materials which contain nuclei up to uranium. After several extensions we apply this toolkit also to proton- and neutron-induced reactions on Am. The fission and radiative neutron capture cross sections, neutron multiplicities and distributions of fission fragments were calculated for 241Am and 243Am and compared with experimental data. As demonstrated, the fission of americium by energetic protons with energies above 20 MeV can be well described by the Intra-Nuclear Cascade Liège (INCL) model combined with the fission-evaporation model ABLA. The calculated average numbers of fission neutrons and mass distributions of fission products agree well with the corresponding data. However, the proton-induced fission below 20 MeV is described less accurately. This is attributed to the limitations of the Intra-Nuclear Cascade model at low projectile energies.

  2. Comparative study of water ice exposures on cometary nuclei using multispectral imaging data

    NASA Astrophysics Data System (ADS)

    Oklay, N.; Sunshine, J. M.; Pajola, M.; Pommerol, A.; Vincent, J.-B.; Mottola, S.; Sierks, H.; Fornasier, S.; Barucci, M. A.; Preusker, F.; Scholten, F.; Lara, L. M.; Barbieri, C.; Lamy, P. L.; Rodrigo, R.; Koschny, D.; Rickman, H.; A'Hearn, M. F.; Bertaux, J.-L.; Bertini, I.; Bodewits, D.; Cremonese, G.; Da Deppo, V.; Davidsson, B. J. R.; Debei, S.; De Cecco, M.; Deller, J.; Fulle, M.; Gicquel, A.; Groussin, O.; Gutiérrez, P. J.; Güttler, C.; Hall, I.; Hofmann, M.; Hviid, S. F.; Ip, W.-H.; Jorda, L.; Keller, H. U.; Knollenberg, J.; Kovacs, G.; Kramm, J.-R.; Kührt, E.; Küppers, M.; Lazzarin, M.; Lin, Z.-Y.; Lopez Moreno, J. J.; Marzari, F.; Naletto, G.; Shi, X.; Thomas, N.; Tubiana, C.

    2016-11-01

    Deep Impact, EPOXI and Rosetta missions visited comets 9P/Tempel 1, 103P/Hartley 2 and 67P/Churyumov-Gerasimenko, respectively. Each of these three missions was equipped with both multispectral imagers and infrared spectrometers. Bright blue features containing water ice were detected in each of these comet nuclei. We analysed multispectral properties of enriched water ice features observed via Optical, Spectroscopic, and Infrared Remote Imaging System narrow angle camera on comet 67P in the wavelength range of 260-1000 nm and then compared with multispectral data of water ice deposits observed on comets 9P and 103P. We characterize the UV/VIS properties of water-ice-rich features observed on the nuclei of these three comets. When compared to the average surface of each comet, our analysis shows that the water ice deposits seen on comet 9P are similar to the clustered water-ice-rich features seen on comet 67P, while the water ice deposit seen on comet 103P is more akin to two large isolated water-ice-rich features seen on comet 67P. Our results indicate that the water ice deposit observed on comet 103P contains more water ice than the water-ice-rich features observed on comets 9P and 67P, proportionally to the average surface of each nucleus.

  3. Femtosecond Raman induced polarization spectroscopy studies of coherent rotational dynamics in molecular fluids

    SciTech Connect

    Morgen, Michael Mark

    1997-05-01

    We develop a polarization-sensitive femtosecond pump probe technique, Raman induced polarization spectroscopy (RIPS), to study coherent rotation in molecular fluids. By observing the collisional dephasing of the coherently prepared rotational states, we are able to extract information concerning the effects of molecular interactions on the rotational motion. The technique is quite sensitive because of the zero background detection method, and is also versatile due to its nonresonant nature.

  4. Influence of fixation point of latissimus dorsi tendon transfer for irreparable rotator cuff tear on glenohumeral external rotation: A cadaver study.

    PubMed

    Bargoin, K; Boissard, M; Kany, J; Grimberg, J

    2016-12-01

    Latissimus dorsi tendon transfer is a surgical option for treating irreparable posterosuperior rotator cuff tears, notably when attempting to reconstruct active external rotation. We hypothesized that the positioning of the transfer's point of fixation would differ depending on the desired elbow-to-body external rotation or external rotation with the elbow abducted. Seven shoulders from four whole frozen cadavers were used. We created two systems to install the subject in a semi-seated position to allow external rotation elbow to body and the arm abducted 90°. Traction sutures were positioned on the latissimus dorsi muscle and a massive tear of the rotator cuff was created. We tested six different transfer positions. Muscle contraction of the latissimus dorsi was stimulated using 10-N and 20-N suspended weights. The point of fixation of the latissimus dorsi on the humeral head had an influence on the elbow-to-body external rotation and with 90° abduction (P<0.001). The fixation point for a maximum external rotation with the elbow to the body was the anterolateral position (P<0.016). The fixation point for a maximum external rotation at 90° abduction was the position centered on the infraspinatus footprint (P<0.078). The optimal point of fixation differs depending on whether external rotation is restored at 0° or 90° abduction. Fundamental study, anatomic study. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  5. Microfractures at the rotator cuff footprint: a randomised controlled study.

    PubMed

    Osti, Leonardo; Del Buono, Angelo; Maffulli, Nicola

    2013-11-01

    Microfractures at the footprint may be a potential additional source of growth factor and enhance the tendon healing at the bone-tendon junction when repairing rotator cuff tears. Fifty-seven patients who underwent shoulder arthroscopy for repair of complete rotator cuff tears were randomly divided into two groups, using a block randomisation procedure. Patients underwent microfracture at the footprint in the treatment group. The patients in the control group (n = 29) did not receive that treatment. All patients had the same post-operative rehabilitation protocol. The two groups were homogeneous. There was a significant improvement from baseline to the last minimum follow-up of two years. At three months from the index procedure, visual analogue scale (VAS), range of motion (ROM) and University of California at Los Angeles (UCLA) and Constant scores were significantly better in group 1 than in group 2 (P < .05). At the last follow-up (minimum two years), clinical and functional outcomes were further improved in both the groups but inter-group differences were not significant. No technique-related complications were recorded. Microfractures at the footprint are simple, safe, inexpensive and effective at producing less pain in the short term in patients who undergo rotator cuff repair, but at two years they do not result in significantly different outcomes, either clinically or at imaging, compared to traditional rotator cuff repair.

  6. Internal rotations of aromatic polyamides: a density functional theory study

    NASA Astrophysics Data System (ADS)

    Nishikawa, Joe; Imase, Tatsuya; Koike, Masao; Fukuda, Kaoru; Tokita, Masatoshi; Watanabe, Junji; Kawauchi, Susumu

    2005-05-01

    Internal rotations of benzanilide ( BA) and 4-(4'-aminobenzamido)benzoic acid ( AA) were investigated by density functional theory (DFT) calculations. B3LYP/6-31G* optimization for both BA and AA structures gives non-planar trans structures as the most stable conformers with lower energy of 4.60 and 5.08 kcal/mol than cis ones, respectively. The amide bond and aniline moiety are found to be coplanar in transBA, while in trans phenyl benzoate ( PB) the ester bond and benzoyl moiety are coplanar. The relaxed potential energy surface (PES) scans were then carried out with rotations of three single bonds, i.e. amide bond and both adjacent bonds. The discontinuous point is found on the relaxed PES for the amide bond rotation. This indicates that inversion of a pyramidal amino group is involved with the amide bond rotation. Therefore, two transition states (TSs) arise for rotation around the amide bond. Two TS structures ( TS-1 and TS-2) were optimized for both BA and AA, and their activation energies were estimated as 14.34 kcal/mol ( TS-1) and 16.27 kcal/mol ( TS-2) for BA, and 12.20 kcal/mol ( TS-1) for AA, respectively. The TS-2 structure for AA failed to be optimized. The activation energy for the amide bond rotation, which is larger than that of 7.90 kcal/mol for PB, as well as the coplanarity in aromatic amide is ascribed to the partial double bond character of amide bond. This is also confirmed by the Wiberg bond index (bond order). The chain persistence length for poly(4-benzamide) was estimated by the rotation matrix formalism using the calculated structural parameters of transAA. The estimated value of 1131 Å is longer than our previously calculated value of corresponding aromatic polyester, 364 Å for poly( p-hydroxybenzoic acid) [T. Imase, S. Kawauchi, J. Watanabe, Macromol. Theory Simul. 10 (2001) 434].

  7. Genetic and environmental sex differences in mental rotation ability: a Japanese twin study.

    PubMed

    Suzuki, Kunitake; Shikishima, Chizuru; Ando, Juko

    2011-10-01

    Sex differences in mental rotation ability have been observed in many countries. A previous study of Finnish participants reported that genetic and environmental influences on mental rotation ability differ between sexes. In this study, we assessed genetic and environmental influences on variance in mental rotation ability in 649 Japanese twins using a mental rotation test. To explain the influence of sex on variance in mental rotation ability, we applied genetic analysis using the sex limitation model. The following two factors explained variance in mental rotation ability: (1) the additive genetic factor, which reflects the accumulated small influence of many genes, and (2) the unique environmental factor, which is a type of environmental factor that differs between co-twins. The shared environmental factor, a type of environmental factor common for co-twins, could not explain the variance in mental rotation ability. Furthermore, the additive genetic factor was the same between sexes (i.e., not qualitative sex differences for the additive genetic factor), indicating that the same genes affect mental rotation ability in both sexes. Despite this observation, the additive genetic influence was greater in males than in females. In contrast, the unique environmental influence was not different between sexes. Considering the current results and those of a previous study, the quantitative sex difference for the additive genetic influences in mental rotation ability may be universal, while the unique environmental differences may depend on the characteristics of specific populations.

  8. Mental rotation of anthropoid hands: a chronometric study.

    PubMed

    Gawryszewski, L G; Silva-dos-Santos, C F; Santos-Silva, J C; Lameira, A P; Pereira, A

    2007-03-01

    It has been shown that mental rotation of objects and human body parts is processed differently in the human brain. But what about body parts belonging to other primates? Does our brain process this information like any other object or does it instead maximize the structural similarities with our homologous body parts? We tried to answer this question by measuring the manual reaction time (MRT) of human participants discriminating the handedness of drawings representing the hands of four anthropoid primates (orangutan, chimpanzee, gorilla, and human). Twenty-four right-handed volunteers (13 males and 11 females) were instructed to judge the handedness of a hand drawing in palm view by pressing a left/right key. The orientation of hand drawings varied from 0 masculine (fingers upwards) to 90 masculine lateral (fingers pointing away from the midline), 180 masculine (fingers downwards) and 90 masculine medial (finger towards the midline). The results showed an effect of rotation angle (F(3, 69) = 19.57, P < 0.001), but not of hand identity, on MRTs. Moreover, for all hand drawings, a medial rotation elicited shorter MRTs than a lateral rotation (960 and 1169 ms, respectively, P < 0.05). This result has been previously observed for drawings of the human hand and related to biomechanical constraints of movement performance. Our findings indicate that anthropoid hands are essentially equivalent stimuli for handedness recognition. Since the task involves mentally simulating the posture and rotation of the hands, we wondered if "mirror neurons" could be involved in establishing the motor equivalence between the stimuli and the participants' own hands.

  9. Conformational Effects on Specific Rotation: A Theoretical Study Based on the S̃k Method.

    PubMed

    Caricato, Marco

    2015-07-30

    In this work, we study the difference in specific rotation of the stable conformers of two test chiral molecules: (S)-(+)-2-carene and (R)-3-methylcyclopentanone. We perform the analysis of the specific rotation in terms of rotational strength in configuration space, S̃k, which provides information about the contribution of occupied-virtual molecular orbital pairs to this property. We show that, although a considerable number of excited configurations contribute to the total value of the specific rotation, only a limited number of configurations are necessary to explain the different sign and magnitude of the rotation between different conformers. The results in this work thus offer a promising picture for our ability to better understand and possibly predict the value of specific rotation of chiral molecules.

  10. MAST - A mass spectrometer telescope for studies of the isotopic composition of solar, anomalous, and galactic cosmic ray nuclei

    NASA Technical Reports Server (NTRS)

    Cook, Walter R.; Cummings, Alan C.; Cummings, Jay R.; Garrard, Thomas L.; Kecman, Branislav; Mewaldt, Richard A.; Selesnick, Richard S.; Stone, Edward C.; Von Rosenvinge, T. T.

    1993-01-01

    The Mass Spectrometer Telescope (MAST) on SAMPEX is designed to provide high resolution measurements of the isotopic composition of energetic nuclei from He to Ni (Z = 2 to 28) over the energy range from about 10 to several hundred MeV/nuc. During large solar flares MAST will measure the isotopic abundances of solar energetic particles to determine directly the composition of the solar corona, while during solar quiet times MAST will study the isotopic composition of galactic cosmic rays. In addition, MAST will measure the isotopic composition of both interplanetary and trapped fluxes of anomalous cosmic rays, believed to be a sample of the nearby interstellar medium.

  11. Properties of nuclei in the nobelium region studied within the covariant, Skyrme, and Gogny energy density functionals

    SciTech Connect

    Dobaczewski, J.; Afanasjev, A. V.; Bender, M.; Shi, Yue

    2015-07-29

    In this study, we calculate properties of the ground and excited states of nuclei in the nobelium region for proton and neutron numbers of 92 ≤ Z ≤ 104 and 144 ≤ N ≤ 156, respectively. We use three different energy-density-functional (EDF) approaches, based on covariant, Skyrme, and Gogny functionals, each with two different parameter sets. A comparative analysis of the results obtained for quasiparticle spectra, odd–even and two-particle mass staggering, and moments of inertia allows us to identify single-particle and shell effects that are characteristic to these different models and to illustrate possible systematic uncertainties related to using the EDF modelling.

  12. Mean-field studies of time reversal breaking states in super-heavy nuclei with the Gogny force

    SciTech Connect

    Robledo, L. M.

    2015-10-15

    Recent progress on the description of time reversal breaking (odd mass and multi-quasiparticle excitation) states in super-heavy nuclei within a mean field framework and using several flavors of the Gogny interaction is reported. The study includes ground and excited states in selected odd mass isotopes of nobelium and mendelevium as well as high K isomeric states in {sup 254}No. These are two and four-quasiparticle excitations that are treated in the same self-consistent HFB plus blocking framework as the odd mass states.

  13. Mean-field studies of time reversal breaking states in super-heavy nuclei with the Gogny force

    NASA Astrophysics Data System (ADS)

    Robledo, L. M.

    2015-10-01

    Recent progress on the description of time reversal breaking (odd mass and multi-quasiparticle excitation) states in super-heavy nuclei within a mean field framework and using several flavors of the Gogny interaction is reported. The study includes ground and excited states in selected odd mass isotopes of nobelium and mendelevium as well as high K isomeric states in 254No. These are two and four-quasiparticle excitations that are treated in the same self-consistent HFB plus blocking framework as the odd mass states.

  14. Study on the Rotation Properties and the Design Issue of Non-Contact Rotating System Using HTS Bulks and Permanent Magnets

    NASA Astrophysics Data System (ADS)

    Okamura, R.; Kim, S. B.; Ozaki, Y.; Ueda, H.

    2017-07-01

    In previous study, non-contact rotating system consisting of the ring-shaped high temperature superconducting (HTS) bulks, ring-shaped permanent magnets (PMs) and stator coil was proposed. In this system, HTS bulks were magnetized by PMs and PMs were levitated with strong restoring force. In our previous study, we have constructed the rotating system with the ring-shaped HTS bulks with ID 20 mm, OD 60 mm, and 15-mm thickness. However, since these bulks costs too much, we switched to use HTS bulks with ID 20 mm, OD 60 mm, and 5-mm-thickness to miniaturize the system. However, this system have potential to fail the radial stability of rotating shaft. Therefore, we focused on the rotating and the radial restoring force in terms of the stability of the rotating shaft in the rotating system with 5-mm thickness HTS bulks.

  15. Effect of Subject Rotation on Assessment of Esthetic Dental Ratios: A Simulation Study

    PubMed Central

    Pokharel, Prabhat Ranjan

    2016-01-01

    Objective. This study aimed to find out the change in esthetic ratios during rotation of patient's head using a simulation. Materials and Methods. A plaster study model was photographed placing its midline along the long axis of the camera. Then a series of photographs were taken by rotating the model each degree till 10° on both right and left sides. These photographs were digitally measured and the ratio of the maxillary anterior teeth at zero-degree rotation was compared with that at various degrees of rotation. Results. As the model was rotated to the right side till 10°, the ratio of the right lateral to central incisor gradually decreased while the ratio of the left lateral to central incisor gradually increased. However, the ratio of the canine to lateral incisor on both sides gradually increased. Similar results were obtained when the model was rotated to the left side. The ratio of the lateral to central incisor deviated from the acceptable range (±10%) when there was rotation of more than 7°, whereas the ratio of the canine to lateral incisor was within the acceptable range till 10° rotation on either side. Conclusions. Rotation of the model by more than 7° leads to a substantial change in the esthetic ratio. PMID:27092181

  16. Study of Kink Modes and Error Fields using Rotation Control with a Biased Probe

    NASA Astrophysics Data System (ADS)

    Stoafer, Chris C.; Levesque, J. P.; Peng, Q.; Mauel, M. E.; Navratil, G. A.

    2015-11-01

    A bias probe has been installed in the High Beta Tokamak - Extended Pulse (HBT-EP) for studying MHD mode rotation and stability. When the probe is inserted into the edge of the plasma and a voltage applied, the rotation of long-wavelength kink instabilities is strongly modified. A large poloidal plasma flow results, measured with a bi-directional Mach probe, and changes in plasma flow correlate to changes in edge kink mode rotation. An active controller is used to adjust the probe voltage in real time for controlling both the plasma flow and mode rotation. Bias probe voltages are generated through an active GPU-based digital feedback system. Mode rotation control is desirable and allows for MHD stability studies under conditions of varying mode rotation rates. At large positive biases, the probe current induces a torque that opposes the natural direction of mode rotation. We are able to apply sufficiently large torque to induce a transition to a fast rotation state (both mode and plasma rotation). The bias required to induce the transition is shown to depend on an applied error field, establishing a technique to determine the natural error field on HBT-EP. Supported by U.S. DOE Grant DE-FG02-86ER53222.

  17. Critical study of the distribution of rotational velocities of Be stars. II: Differential rotation and some hidden effects interfering with the interpretation of the V sin i parameter

    NASA Astrophysics Data System (ADS)

    Zorec, J.; Frémat, Y.; Domiciano de Souza, A.; Royer, F.; Cidale, L.; Hubert, A.-M.; Semaan, T.; Martayan, C.; Cochetti, Y. R.; Arias, M. L.; Aidelman, Y.; Stee, P.

    2017-06-01

    Aims: We assume that stars may undergo surface differential rotation to study its impact on the interpretation of Vsini and on the observed distribution Φ(u) of ratios of true rotational velocities u = V/Vc (Vc is the equatorial critical velocity). We discuss some phenomena affecting the formation of spectral lines and their broadening, which can obliterate the information carried by Vsini concerning the actual stellar rotation. Methods: We studied the line broadening produced by several differential rotational laws, but adopted Maunder's expression Ω(θ) = Ω0(1 + αcos2θ) as an attempt to account for all of these laws with the lowest possible number of free parameters. We studied the effect of the differential rotation parameter α on the measured Vsini parameter and on the distribution Φ(u) of ratios u = V/Vc. Results: We conclude that the inferred Vsini is smaller than implied by the actual equatorial linear rotation velocity Veq if the stars rotate with α < 0, but is larger if the stars have α > 0. For a given | α | the deviations of Vsini are larger when α < 0. If the studied Be stars have on average α < 0, the number of rotators with Veq ≃ 0.9Vc is larger than expected from the observed distribution Φ(u); if these stars have on average α > 0, this number is lower than expected. We discuss seven phenomena that contribute either to narrow or broaden spectral lines, which blur the information on the rotation carried by Vsini and, in particular, to decide whether the Be phenomenon mostly rely on the critical rotation. We show that two-dimensional radiation transfer calculations are needed in rapid rotators to diagnose the stellar rotation more reliably.

  18. Comparative studies for different proximity potentials applied to large cluster radioactivity of nuclei

    NASA Astrophysics Data System (ADS)

    Zhang, G. L.; Yao, Y. J.; Guo, M. F.; Pan, M.; Zhang, G. X.; Liu, X. X.

    2016-07-01

    Half-lives of large cluster radioactivity of even-even nuclei calculated by using fourteen proximity potentials are compared to experimental data. The results show that the results of BASS77 and Denisov potentials are most agreeable with the experimental data. Christensen and Winther 1976 potential gives the smallest half-lives. In comparison with the distributions of different proximity potentials and the distributions of total potentials when the values of total potentials are more than the released energy Qc, it is found that at the small distances the large differences of proximity potentials do not affect the calculation results. The different distributions of total potentials affect the penetration probability of large cluster radioactivity, and then affect the half-life of large cluster radioactivity.

  19. Distribution of primary afferent fibres in the cochlear nuclei. A silver and horseradish peroxidase (HRP) study.

    PubMed Central

    Merchan, M A; Collia, F P; Merchan, J A; Saldana, E

    1985-01-01

    Horseradish peroxidase, when injected intracochlearly, is transported transganglionically to the brain stem cochlear nuclei, thus providing an excellent method for tracing the central projection of the spiral ganglion neurons. Silver impregnation using the Cajal-de Castro method, which stains axons even when inside the bone, was used as a reference technique. The combination of both procedures led to the following conclusions. Primary cochlear afferents are found only in the ventral zone of the dorsal cochlear nucleus. In this area they cover the deep and fusiform cell layers. The molecular layer shows no HRP label. The higher concentration of primary cochlear afferents in the ventral cochlear nucleus appears in its central zone; wide areas in this nucleus are not labelled at all. A thin bundle of primary cochlear afferents runs parallel to, and beneath, the granular region. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:4077711

  20. The superdeformation phenomenon in atomic nuclei

    NASA Astrophysics Data System (ADS)

    Meyer, M.; Vivien, J. P.

    After the discovery of discrete rotational bands corresponding to superdeformed nuclei with spin around 60h, the study of the structure of these nuclei over the last five years has witnessed a significant expansion in physical understanding with the emergence of new phenomena and in a technical development with the construction of sophisticated apparatus to examine these nuclei. On the eve of the approaching operation of news detectors such as EUROGAM resulting from a French-British collaboration,or the American GAMMASPHERE, this article discusses the present state of knowledge on superdeformation and exposes the theoretical basis as well as recent experimental results in the field. Avec la découverte de bandes de rotations discrètes correspondant à des noyaux superdéformés ayant des moments angulaires avoisinant 60h, l'étude de la structure de ces noyaux connait depuis les cinq dernières années un essor important tant sur le plan de la physique avec l'apparition de phénomènes nouveaux que sur le plan de la technique avec le développement d'appareillages sophistiqués pour scruter ces noyaux. A la veille de l'entrée en fonction de nouveaux détecteurs comme EUROGAM issu d'une collaboration Franco-Britannique ou GAMMASPHERE résultant des efforts des laboratoires Americains, cet article fait le point des connaissances actuelles sur la superdéformation et relate les acquis théoriques ainsi que les resultats expérimentaux accumulés récemment dans ce domaine.

  1. Alpha decay studies of {sup 189}Bi{sup m}, {sup 190}Po and {sup 180 }Pb using a rapidly rotating recoil catcher wheel system

    SciTech Connect

    Batchelder, J.C.; Toth, K.S.; Moltz, D.M.

    1996-09-01

    The {alpha} decays of very neutron deficient nuclei near the Z = 82 closed proton shell are of interest because they provide us with structure information that is relevant with regard to the shell model. We used a rapidly rotating recoil catcher wheel system to study the {alpha} decays of {sup 189}Bi{sup {ital m}}, {sup 190}Po, and {sup 180}Pb. The system works as follows. Recoils from the back of the target, after passing through an Al degrader placed behind the target, are stopped in 300-{mu}g/cm{sup 2} Al catcher foils fixed at the edges of the wheel. These are inclined at an angle of 20 degrees with respect to the beam to maximize the catcher efficiency while keeping the thickness that {alpha} particles must travel in order to emerge of the Al foil to a minimum. This arrangement results in an effective thickness of {approx} 900 {mu}g/cm{sup 2} for recoils, but only 150 {mu}g/cm{sup 2} for the emitted {alpha} particles. Stopped recoils are then rotated between an array of 6 Si detectors in series (solid angle of 8% of 4{pi}). Half-life information can be obtained by determining the difference in counts between the detectors. This instrument has proven to be an effective tool for the study of nuclei far from stability with half-lives in the range of 1-50 ms.

  2. Excitatory and inhibitory innervation of the mouse orofacial motor nuclei: A stereological study.

    PubMed

    Faunes, Macarena; Oñate-Ponce, Alejandro; Fernández-Collemann, Sara; Henny, Pablo

    2016-03-01

    Neurons in the trigeminal (Mo5), facial (Mo7), ambiguus (Amb), and hypoglossal (Mo12) motor nuclei innervate jaw, facial, pharynx/larynx/esophagus, and tongue muscles, respectively. They are essential for movements subserving feeding, exploration of the environment, and social communication. These neurons are largely controlled by sensory afferents and premotor neurons of the reticular formation, where central pattern generator circuits controlling orofacial movements are located. To provide a description of the orofacial nuclei of the adult mouse and to ascertain the influence of excitatory and inhibitory afferents upon them, we used stereology to estimate the number of motoneurons as well as of varicosities immunopositive for glutamate (VGluT1+, VGluT2+) and GABA/glycine (known as VIAAT+ or VGAT+) vesicular transporters in the Mo5, Mo7, Amb, and Mo12. Mo5, Mo7, Amb, and Mo12 contain ∼1,000, ∼3,000, ∼600, and ∼1,700 cells, respectively. VGluT1+, VGluT2+, and VIAAT+ varicosities respectively represent: 28%, 41%, and 31% in Mo5; 2%, 49%, and 49% in Mo7; 12%, 42%, and 46% in Amb; and 4%, 54%, and 42% in Mo12. The Mo5 jaw-closing subdivision shows the highest VGluT1+ innervation. Noticeably, the VGluT2+ and VIAAT+ varicosity density in Mo7 is 5-fold higher than in Mo5 and 10-fold higher than in Amb and Mo12. The high density of terminals in Mo7 likely reflects the convergence and integration of numerous inputs to motoneurons subserving the wide range of complex behaviors to which this nucleus contributes. Also, somatic versus neuropil location of varicosities suggests that most of these afferents are integrated in the dendritic trees of Mo7 neurons.

  3. Study of 11Li and 10,11Be nuclei through elastic scattering and breakup reactions

    NASA Astrophysics Data System (ADS)

    Gaidarov, M. K.; Lukyanov, V. K.; Kadrev, D. N.; Zemlyanaya, E. V.; Antonov, A. N.; Lukyanov, K. V.; Spasova, K.

    2016-01-01

    The hybrid model of the microscopic optical potential (OP) is applied to calculate the 11Li+p, 10,11Be+p, and 10,11Be+12C elastic scattering cross sections at energies E < 100 MeV/nucleon. The OP's contain the folding-model real part (ReOP) with the direct and exchange terms included, while its imaginary part (ImOP) is derived within the high-energy approximation (HEA) theory. For the 11Li+p elastic scattering, the microscopic large-scale shell model (LSSM) density of 11Li is used, while the density distributions of 10,11Be nuclei obtained within the quantum Monte Carlo (QMC) model and the generator coordinate method (GCM) are utilized to calculate the microscopic OPs and cross sections of elastic scattering of these nuclei on protons and 12C. The depths of the real and imaginary parts of OP are fitted to the elastic scattering data, being simultaneously adjusted to reproduce the true energy dependence of the corresponding volume integrals. Also, the cluster models, in which 11Li consists of 2n-halo and the 9Li core having its own LSSM form of density and 11Be consists of a n-halo and the 10Be core, are adopted. Within the latter, we give predictions for the longitudinal momentum distributions of 9Li fragments produced in the breakup of 11Li at 62 MeV/nucleon on a proton target. It is shown that our results for the diffraction and stripping reaction cross sections in 11Be scattering on 9Be, 93Nb, 181Ta, and 238U targets at 63 MeV/nucleon are in a good agreement with the available experimental data.

  4. Sex chromosome loss and aging: in situ hybridization studies on human interphase nuclei.

    PubMed Central

    Guttenbach, M; Koschorz, B; Bernthaler, U; Grimm, T; Schmid, M

    1995-01-01

    A total of 1,000 lymphocyte interphase nuclei per proband from 90 females and 138 males age 1 wk to 93 years were analyzed by in situ hybridization for loss of the X and Y chromosomes, respectively. Both sex chromosomes showed an age-dependent loss. In males, Y hypoploidy was very low up to age 15 years (0.05%) but continuously increased to a frequency of 1.34% in men age 76-80 years. In females, the baseline level for X chromosome loss is much higher than that seen for the Y chromosome in males. Even prepubertal females show a rate of X chromosome loss, on the order of 1.5%-2.5%, rising to approximately 4.5%-5% in women older than 75 years. Dividing the female probands into three biological age groups on the basis of sex hormone function (< 13 years, 13-51 years, and > 51 years), a significant correlation of X chromosome loss versus age could clearly be demonstrated in women beyond age 51 years. Females age 51-91 years showed monosomy X at a rate from 3.2% to 5.1%. In contrast to sex chromosomal loss, the frequency of autosomal monosomies does not change during the course of aging: Chromosome 1 and chromosome 17 monosomic cells were found with a constant incidence of 1.2% and 1%, respectively. These data also indicate that autosome loss in interphase nuclei is not a function of chromosome size. Images Figure 1 Figure 2 PMID:7485166

  5. A detailed study of nucleon structure function in nuclei in the valence quark region

    SciTech Connect

    Bianchi, N.

    1994-04-01

    The so called {open_quotes}EMC effect{close_quotes} discovered during the 1980`s, has caused a big controversy in the community of nuclear and high energy physicists; during the last ten years, five experiments have been performed in different laboratories and several hundreds of papers about the possible interpretation of the modification of the nucleon structure function inside nuclei have been published. However, from the experimental point of view, the main goal of four experiments (EMC, BCDMS, NMC, FNAL) has been to emphasize the region of low x{sub b}, where shadowing effects appear. In the region of valence quarks and nuclear effects (x{sub b} > 0.1 - 0.2) the most reliable data presently available are from the SLAC E139 experiment performed in 1983 with only 80 hours of beam time. New precise data in the valence quark region are necessary to measure separate structure functions F{sub 2}(x{sub b}, Q{sup 2}) and R{sup lt}(x{sub b},Q{sup 2}) = {sigma}{sub l}/{sigma}{sub t}, and to investigate the real A-dependence of the ratio between bound and free-nucleon structure functions which is not completely defined by the SLAC data. Moreover, from the nuclear physics point of view, a measurement on some unexplored nuclei, like {sup 3}He and {sup 48}Ca, would be of great interest. The intermediate scaling region (0.1 < x{sub b} < 0.7) would be accessible at CEBAF if the machine energy will reach 6-8 GeV, as suggested by all the tests performed on the RF cavities. This physics program has been already presented in two letter of intents.

  6. Long-term study of cloud condensation nuclei (CCN) activation of the atmospheric aerosol in Vienna

    PubMed Central

    Burkart, J.; Steiner, G.; Reischl, G.; Hitzenberger, R.

    2011-01-01

    During a total of 11 months, cloud condensation nuclei (CCN at super-saturation S 0.5%) and condensation nuclei (CN) concentrations were measured in the urban background aerosol of Vienna, Austria. For several months, number size distributions between 13.22 nm and 929 nm were also measured with a scanning mobility particle spectrometer (SMPS). Activation ratios (i.e. CCN/CN ratios) were calculated and apparent activation diameters obtained by integrating the SMPS size distributions. Variations in all CCN parameters (concentration, activation ratio, apparent activation diameter) are quite large on timescales of days to weeks. Passages of fronts influenced CCN parameters. Concentrations decreased with the passage of a front. No significant differences were found for fronts from different sectors (for Vienna mainly north to west and south to east). CCN concentrations at 0.5% S ranged from 160 cm−3 to 3600 cm−3 with a campaign average of 820 cm−3. Activation ratios were quite low (0.02–0.47, average: 0.13) and comparable to activation ratios found in other polluted regions (e.g. Cubison et al., 2008). Apparent activation diameters were found to be much larger (campaign average: 169 nm, range: (69–370) nm) than activation diameters for single-salt particles (around 50 nm depending on the salt). Contrary to CN concentrations, which are influenced by source patterns, CCN concentrations did not exhibit distinct diurnal patterns. Activation ratios showed diurnal variations counter-current to the variations of CN concentrations. PMID:21977003

  7. Sex chromosome loss and aging: In situ hybridization studies on human interphase nuclei

    SciTech Connect

    Guttenbach, M.; Koschorz, B.; Bernthaler, U.

    1995-11-01

    A total of 1,000 lymphocyte interphase nuclei per proband from 90 females and 138 males age 1 wk to 93 years were analyzed by in situ hybridization for loss of the X and Y chromosomes, respectively. Both sex chromosomes showed an age-dependent loss. In males, Y hypoploidy was very low up to age 15 years (0.05%) but continuously increased to a frequency of 1.34% in men age 76-80 years. In females, the baseline level for X chromosome loss is much higher than that seen for the Y chromosome in males. Even prepubertal females show a rate of X chromosome loss on the order of 1.5%-2.5%, rising to {approximately}4.5%-5% in women older than 75 years. Dividing the female probands into three biological age groups on the basis of sex hormone function (<13 years, 13-51 years, and >51 years), a significant correlation of X chromosome loss versus age could clearly be demonstrated in women beyond age 51 years. Females age 51-91 years showed monosomy X at a rate from 3.2% to 5.1%. In contrast to sex chromosomal loss, the frequency of autosomal monosomies does not change during the course of aging: chromosome 1 and chromosome 17 monosomic cells were found with a constant incidence of 1.2% and 1%, respectively. These data also indicate that autosome loss in interphase nuclei is not a function of chromosome size. 34 refs., 5 figs., 6 tabs.

  8. Descriptive study of the even-even actinide nuclei 230 - 234Th isotopes using IBM-1

    NASA Astrophysics Data System (ADS)

    Al-Dahan, N.

    2017-06-01

    The nuclear structure of the actinide even-even thorium isotopes from A=230-234 have been investigated within the framework of the Interacting Boson Model (IBM-1). Predictions are given for the excited state energies for the ground state, β and γ-bands, the transition probabilities between these states, the rotational moment of inertia, and the energy staggering in the γ-band energies. The results of these calculations are compared with the experimental data on these isotopes.

  9. Numerical study for MHD peristaltic flow in a rotating frame.

    PubMed

    Hayat, T; Zahir, Hina; Tanveer, Anum; Alsaedi, A

    2016-12-01

    The aim of present investigation is to model and analyze the magnetohydrodynamic (MHD) peristaltic transport of Prandtl fluid in a channel with flexible walls. The whole system consisting of fluid and channel are in a rotating frame of reference with uniform angular velocity. Viscous dissipation in thermal equation is not ignored. The channel boundaries satisfy the convective conditions in terms of temperature. The arising complicated problems are reduced in solvable form using large wavelength and small Reynolds number assumptions. Numerical solution for axial and secondary velocities, temperature and heat transfer coefficient are presented. Main emphasis is given to the outcome of rotation and material parameters of Prandtl fluid on the physical quantities of interest.

  10. Effects of ventricular insertion sites on rotational motion of left ventricular segments studied by cardiac MR

    PubMed Central

    Robson, M D; Rider, O J; Pegg, T J; Dasanu, C A; Jung, B A; Clarke, K; Holloway, C J

    2013-01-01

    Objective: Obtaining new details for rotational motion of left ventricular (LV) segments using velocity encoding cardiac MR and correlating the regional motion patterns to LV insertion sites. Methods: Cardiac MR examinations were performed on 14 healthy volunteers aged between 19 and 26 years. Peak rotational velocities and circumferential velocity curves were obtained for 16 ventricular segments. Results: Reduced peak clockwise velocities of anteroseptal segments (i.e. Segments 2 and 8) and peak counterclockwise velocities of inferoseptal segments (i.e. Segments 3 and 9) were the most prominent findings. The observations can be attributed to the LV insertion sites into the right ventricle, limiting the clockwise rotation of anteroseptal LV segments and the counterclockwise rotation of inferoseptal segments as viewed from the apex. Relatively lower clockwise velocities of Segment 5 and counterclockwise velocities of Segment 6 were also noted, suggesting a cardiac fixation point between these two segments, which is in close proximity to the lateral LV wall. Conclusion: Apart from showing different rotational patterns of LV base, mid ventricle and apex, the study showed significant differences in the rotational velocities of individual LV segments. Correlating regional wall motion with known orientation of myocardial aggregates has also provided new insights into the mechanisms of LV rotational motions during a cardiac cycle. Advances in knowledge: LV insertion into the right ventricle limits the clockwise rotation of anteroseptal LV segments and the counterclockwise rotation of inferoseptal segments adjacent to the ventricular insertion sites. The pattern should be differentiated from wall motion abnormalities in cardiac pathology. PMID:24133098

  11. Coulomb Excitation and One-Neutron Transfer Studies of Stable and Radioactive Nuclei at HRIBF-ORNL

    SciTech Connect

    Allmond, James M

    2015-01-01

    Several stable and radioactive nuclei ranging from $A=58$ to 208 were recently studied in inverse kinematics by Coulomb excitation and heavy-ion induced one-neutron transfer at the Holifield Radioactive Ion Beam Facility of Oak Ridge National Laboratory. These studies used a CsI-HPGe detector array to detect scattered charged particles and emitted $\\gamma$ rays from the in-beam reactions. A Bragg-curve detector was used to measure the energy loss of the various beams through the targets and to measure the radioactive beam compositions. Stable nickel, strontium, zirconium, molybdenum, tin, tellurium, and lead isotopes and neutron-rich radioactive tin and tellurium isotopes were among the nuclei recently studied. Coulomb excitation was used to measure the electromagnetic moments of the first excited states and heavy-ion induced one-neutron transfer was used to measure the absolute cross sections and lifetimes of the excited single-particle states. A sample of these results are presented here with an emphasis on the tin isotopes. In particular, a survey of the Bragg-curve measurements, Doppler corrections, and inconclusive $i_{13/2}$ candidate in $^{133}$\\textrm{Sn} are presented.

  12. Studying the Stereochemistry of Naproxen Using Rotationally Resolved Electronic Spectroscopy.

    NASA Astrophysics Data System (ADS)

    Young, Justin W.; Alvarez-Valtierra, Leonardo; Pratt, David W.

    2009-06-01

    Many biochemical processes are stereospecific. An example is the physiological response to a drug that depends on its enantiomeric form. Naproxen is a drug which shows this stereo-specific physiological response. To better understand the stereo specificity of chiral substances, we observed the S_1←S_0 transitions of R- and S-naproxen in the gas phase using rotationally resolved electronic spectroscopy. The results will be discussed.

  13. Numerical study of rotating interstellar clouds: equilibrium and collapse

    SciTech Connect

    Norman, M.L.

    1980-06-01

    Equilibrium and collapse of rotating, axisymmetric, idealized interstellar gas clouds is calculated with a 2D hydrodynamics code. The hydrodynamics features an improved angular momentum advection algorithm. Angular momentum is advected consistently with mass by deriving angular momentum fluxes from mass fluxes and the local distribution of specific angular momentum. Local conservation is checked by a graph of mass versus specific angular momentum for the cloud as a whole.

  14. Study on Parallel 2-DOF Rotation Machanism in Radar

    NASA Astrophysics Data System (ADS)

    Jiang, Ming; Hu, Xuelong; Liu, Lei; Yu, Yunfei

    The spherical parallel machine has become the world's academic and industrial focus of the field in recent years due to its simple and economical manufacture as well as its structural compactness especially suitable for areas where space gesture changes. This paper dwells upon its present research and development home and abroad. The newer machine (RGRR-II) can rotate around the axis z within 360° and the axis y1 from -90° to +90°. It has the advantages such as less moving parts (only 3 parts), larger ratio of work space to machine size, zero mechanic coupling, no singularity. Constructing rotation machine with spherical parallel 2-DOF rotation join (RGRR-II) may realize semispherical movement with zero dead point and extent the range. Control card (PA8000NT Series CNC) is installed in the computer. The card can run the corresponding software which realizes radar movement control. The machine meets the need of radars in plane and satellite which require larger detection range, lighter weight and compacter structure.

  15. A Study of Co-Rotating Wake Vortex Instabilities

    NASA Astrophysics Data System (ADS)

    Bristol, Robert; Savas, Omer

    2000-11-01

    Observations of an instability between pairs of co-rotating wake vortices produced from a flapped airfoil are presented. Data from particle imaging velocimetry and flow-visualization show the growth of a periodic disturbance on the weaker vortex, leading to merger of the two vortices in approximately one orbit. The instability grows in a plane inclined at 45 degrees with respect to the line connecting the two vortices, suggesting that it is driven by the straining field of the stronger vortex acting upon the weaker one. A linear stability analysis of the problem is presented, which is a generalization of the Crow theory, covering the case for an unequal pair of vortices. Within the confines of this analysis, the straining field emerges as the primary mechanism for instability, with the effects of self-rotation and orbit-induced rotation acting together to stabilize the pair. However, the linear theory fails to reproduce the experimental results, most likely because of strong interactions due to the close proximity of the finite-size vortices. Finally, results are shown from the spectral Navier-Stokes solver in cylindrical co-ordinates of Marcus et. al., which produces instabilities similar to the ones observed experimentally. Circulation-based Reynolds numbers for the experiments reach 300,000 while those for the simulations reach 60,000.

  16. Laboratory Study of Magnetohydrodynamic and Hydrodynamic Instabilities in Rotating Flows Relevant to Astrophysical Disks

    NASA Astrophysics Data System (ADS)

    Ji, Hantao

    Efficient dissipation of the orbital energy of plasma occurs in accretion disks ranging from those in which planets form around protostars, to those around supermassive black holes in active galactic nuclei. Two mechanisms have been proposed for the turbulence that drives dissipation and angular-momentum transport in such disks: (1) a linear instability of magnetized and electrically conducting flow known as magnetorotational instability (MRI); and (2) nonlinear hydrodynamic shear-flow instability. Two laboratory apparatuses have been constructed at Princeton to study these mechanisms. The LiquidMetal MRI experiment is designed to study MRI and related MHD instabilities. The Hydrodynamic Turbulence Experiment (HTX) is designed to study nonlinear hydrodynamic transition. Both of these devices are novel in two respects: large Reynolds numbers (Regtrsim 10(6) ) and multiple independently driven rings on the axial boundaries to minimize secondary (Ekman) flows. We have demonstrated negligible angular momentum transport at Re ≤ 2× 10(6) in quasi-keplerian hydrodynamic flow with minimized Ekman circulation. This result, published in Nature, has generated significant interest among astrophysicists and fluid dynamicists. Recently, the MHD experiment has demonstrated robust nonaxisymmetric Shercliff-layer instabilities in strong axial magnetic fields. The latter result has paved a clear path towards first conclusive demonstration of MRI in the laboratory. Support is requested to continue fundamental laboratory studies with these devices. The proposed research will focus on experimental studies of the following major questions: (Q1) Why are quasi-keplerian flows resistant to turbulence? Can the turbulence found by other experiments be explained by differences in the boundary conditions or diagnostics used? Can nonlinear hydrodynamic transition occur in flow that is partially magnetized but too diffusive for MRI? (Q2) How do MRI, Shercliff-layer instabilities, and other

  17. 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.

  18. A maize root tip system to study DNA replication programmes in somatic and endocycling nuclei during plant development.

    PubMed

    Bass, Hank W; Wear, Emily E; Lee, Tae-Jin; Hoffman, Gregg G; Gumber, Hardeep K; Allen, George C; Thompson, William F; Hanley-Bowdoin, Linda

    2014-06-01

    The progress of nuclear DNA replication is complex in both time and space, and may reflect several levels of chromatin structure and 3-dimensional organization within the nucleus. To understand the relationship between DNA replication and developmental programmes, it is important to examine replication and nuclear substructure in different developmental contexts including natural cell-cycle progressions in situ. Plant meristems offer an ideal opportunity to analyse such processes in the context of normal growth of an organism. Our current understanding of large-scale chromosomal DNA replication has been limited by the lack of appropriate tools to visualize DNA replication with high resolution at defined points within S phase. In this perspective, we discuss a promising new system that can be used to visualize DNA replication in isolated maize (Zea mays L.) root tip nuclei after in planta pulse labelling with the thymidine analogue, 5-ethynyl-2'-deoxyuridine (EdU). Mixed populations of EdU-labelled nuclei are then separated by flow cytometry into sequential stages of S phase and examined directly using 3-dimensional deconvolution microscopy to characterize spatial patterns of plant DNA replication. Combining spatiotemporal analyses with studies of replication and epigenetic inheritance at the molecular level enables an integrated experimental approach to problems of mitotic inheritance and cellular differentiation.

  19. Studies of the composition of solar particles and of energetic oxygen and sulfur nuclei trapped in the Jovian magnetosphere

    NASA Technical Reports Server (NTRS)

    Stone, E. C.

    1986-01-01

    The Cosmic Ray System (CRS) experiment on board each of the Voyager 1 and 2 spacecraft consists of four Low Energy Telescopes (LETs), two High Energy Telescopes (HETs), the Electron Telescope (TET), and associated electronics. With these instruments it is possible to measure the energy spectrum of electrons over the 3-110MeV energy range and the energy spectra and nuclear charge of atomic nuclei from hydrogen through zinc over the 3-500 MeV/nuc energy range. The exclusive use of solid-state detectors in the CRS telescopes achieves the objectives of reliability over a long mission life, high resolution determinations of energy and charge, and high-count-rate capability during large solar flares and passage through the magnetospheres of the outer planets. Summarized here are some of the many accomplishments that have resulted from the CRS measurements during the period covered by this report, May 15, 1981 to May 15, 1984, including studies of the energetic oxygen and sulfur nuclei trapped in the Jovian magnetosphere.

  20. Study of cluster structures in 10Be and 16C neutron-rich nuclei via break-up reactions

    NASA Astrophysics Data System (ADS)

    Dell'Aquila, D.; Acosta, L.; Amorini, F.; Andolina, R.; Auditore, L.; Berceanu, I.; Cardella, G.; Chatterjiee, M. B.; De Filippo, E.; Francalanza, L.; Gnoffo, B.; Grzeszczuk, A.; Lanzalone, G.; Lombardo, I.; Martorana, N.; Minniti, T.; Pagano, A.; Pagano, E. V.; Papa, M.; Pirrone, S.; Politi, G.; Pop, A.; Porto, F.; Quattrocchi, L.; Rizzo, F.; Rosato, E.; Russotto, P.; Trifirò, A.; Trimarchi, M.; Verde, G.; Vigilante, M.

    2016-05-01

    Projectile break-up reactions induced on polyethylene (CH2) target are used in order to study the spectroscopy of 10Be and 16C nuclei. For the present experiment we used 10Be and 16C beams delivered by the FRIBs facility at INFN-LNS, and the CHIMERA 4π multi-detector. 10Be and 16C structures are studied via a relative energy analysis of break-up fragments. The 4He+6He break-up channel allowed us to study the spectroscopy of 10Be; in particular we find evidence of a new state in 10Be at 13.5 MeV excitation energy. The 16C nucleus is studied via 6He-10Be correlation; we find the fingerprint of a possible state at about 20.6 MeV

  1. Parameter Studies on Rotational and Translational Accelerations of Flat Plates

    DTIC Science & Technology

    2013-01-01

    A., and Schlueter, K. “The Effects of Wall Boundaries on the Flow Field of a Rotating Wing”. AIAA 2012-2776. 7 OL, M. V., Bernal , L., Kang, C.-K...K., OL, M., and Bernal , L. “Experiments on Pitching Plates: Force and Flowfield Measurements at Low Reynolds Numbers”. AIAA – 2011- 0872 9...Granlund, K., OL, M., Bernal , L., and Kast, S. “Experiments on Free-to-Pivot Hover Motions of Flat Plates”. AIAA-2010- 4456. 10 McGowan, G., Granlund, K

  2. Study of torus structure of low-luminosity active galactic nuclei with Suzaku

    NASA Astrophysics Data System (ADS)

    Kawamuro, T.

    2015-09-01

    We investigate the nature of the torus structure of eight low-luminosity active galactic nuclei (LLAGNs; NGC 1566, NGC 2655, NGC 3718, NGC 3998, NGC 4138, NGC 4941, NGC 5273 and NGC 5643) based on the broad band X-ray spectra (0.5-200 keV) obtained with Suzaku and Swift/BAT. Their X-ray luminosities are smaller than 1e 42 erg/s, while the Eddington ratios span a range from 1e-4 to 1e-2. No significant iron- Kalpha line is detected in the spectra of two LLAGNs with the lowest Eddington ratios (<3e-4) in our sample (NGC 3718 and NGC 3998), suggesting that their tori are little developed. The others show the iron-Kalpha equivalent widths larger than 100 eV. For these six LLAGNs, we utilize the Monte-Carlo based simulation code by Ikeda 09 to constrain the torus parameters by assuming a nearly spherical geometry. The torus solid- angles in three sources (NGC 2655, NGC 4138, and NGC 4941) are constrained to be Omega/2pi > 0.34, and the rest are found to have torus column-densities of logNrmH > 22.7. These results suggest that there are two types of LLAGNs, (1) those where the torus is very small and little mass accretion takes place, and (2) those where the torus is moderately developed and a sufficient amount of gas is supplied to the black hole.

  3. Experimental study of the two-body spin-orbit force in nuclei.

    PubMed

    Burgunder, G; Sorlin, O; Nowacki, F; Giron, S; Hammache, F; Moukaddam, M; de Séréville, N; Beaumel, D; Càceres, L; Clément, E; Duchêne, G; Ebran, J P; Fernandez-Dominguez, B; Flavigny, F; Franchoo, S; Gibelin, J; Gillibert, A; Grévy, S; Guillot, J; Lepailleur, A; Matea, I; Matta, A; Nalpas, L; Obertelli, A; Otsuka, T; Pancin, J; Poves, A; Raabe, R; Scarpaci, J A; Stefan, I; Stodel, C; Suzuki, T; Thomas, J C

    2014-01-31

    Energies and spectroscopic factors of the first 7/2-, 3/2-, 1/2-, and 5/2- states in the (35)Si21 nucleus were determined by means of the (d, p) transfer reaction in inverse kinematics at GANIL using the MUST2 and EXOGAM detectors. By comparing the spectroscopic information on the Si35 and S37 isotones, a reduction of the p3/2-p1/2 spin-orbit splitting by about 25% is proposed, while the f7/2-f5/2 spin-orbit splitting seems to remain constant. These features, derived after having unfolded nuclear correlations using shell model calculations, have been attributed to the properties of the two-body spin-orbit interaction, the amplitude of which is derived for the first time in an atomic nucleus. The present results, remarkably well reproduced by using several realistic nucleon-nucleon forces, provide a unique touchstone for the modeling of the spin-orbit interaction in atomic nuclei.

  4. Nuclear Structure Studies of Exotic Nuclei with Radioactive Ion Beams A Final Report

    SciTech Connect

    Winger, Jeff Allen

    2016-04-21

    Beta-decay spectroscopy provides important information on nuclear structure and properties needed to understand topics as widely varied as fundamental nuclear astrophysics to applied nuclear reactor design. However, there are significant limitations of our knowledge due to an inability to experimentally measure everything. Therefore, it is often necessary to rely on theoretical calculations which need to be vetted with experimental results. The focus of this report will be results from experimental research performed by the Principal Investigator (PI) and his research group at Mississippi State University in which the group played the lead role in proposing, implementing, performing and analyzing the experiment. This research was carried out at both the National Superconduction Cyclotron Laboratory (NSCL) at Michigan State University and the Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National Laboratory. The primary emphasis of the research was the use of \\bdec spectroscopy as a tool to understand the evolution of nuclear structure in neutron-rich nuclei which could then be applied to improve theory and to increase the overall knowledge of nuclear structure.

  5. Experimental Study of the Two-Body Spin-Orbit Force in Nuclei

    NASA Astrophysics Data System (ADS)

    Burgunder, G.; Sorlin, O.; Nowacki, F.; Giron, S.; Hammache, F.; Moukaddam, M.; de Séréville, N.; Beaumel, D.; Càceres, L.; Clément, E.; Duchêne, G.; Ebran, J. P.; Fernandez-Dominguez, B.; Flavigny, F.; Franchoo, S.; Gibelin, J.; Gillibert, A.; Grévy, S.; Guillot, J.; Lepailleur, A.; Matea, I.; Matta, A.; Nalpas, L.; Obertelli, A.; Otsuka, T.; Pancin, J.; Poves, A.; Raabe, R.; Scarpaci, J. A.; Stefan, I.; Stodel, C.; Suzuki, T.; Thomas, J. C.

    2014-01-01

    Energies and spectroscopic factors of the first 7/2-, 3/2-, 1/2-, and 5/2- states in the Si2135 nucleus were determined by means of the (d, p) transfer reaction in inverse kinematics at GANIL using the MUST2 and EXOGAM detectors. By comparing the spectroscopic information on the Si35 and S37 isotones, a reduction of the p3/2-p1/2 spin-orbit splitting by about 25% is proposed, while the f7/2-f5/2 spin-orbit splitting seems to remain constant. These features, derived after having unfolded nuclear correlations using shell model calculations, have been attributed to the properties of the two-body spin-orbit interaction, the amplitude of which is derived for the first time in an atomic nucleus. The present results, remarkably well reproduced by using several realistic nucleon-nucleon forces, provide a unique touchstone for the modeling of the spin-orbit interaction in atomic nuclei.

  6. The forbidden rotational Q branch of CH 3SiF 3: A study in internal rotation

    NASA Astrophysics Data System (ADS)

    Styger, C.; Ozier, I.; Wang, S.-X.; Bauder, A.

    2006-09-01

    The pure rotational spectrum driven by the small dipole moment produced perpendicular to the symmetry axis by centrifugal distortion has been investigated for CH 3SiF 3 in the ground vibrational state using a Fourier transform waveguide spectrometer. Between 10.9 and 17.0 GHz, four ( k + 3 ← k) series in the Q branch have been measured in the lowest torsional state v6 = 0 for k = 4, 5, 6, and 7 with 54 ⩽ J ⩽ 65. In each transition, the quantum number σ = 0, +1, -1 labelling the different torsional sub-levels is conserved. For given ( J, k), splittings from ˜10 to ˜45 MHz have been observed between lines with different values of σ. The global data set includes the anticrossing molecular beam energy differences of [W.L. Meerts, I. Ozier, Chem. Phys. 71 (1982) 401-415] as well as the mm-wave R branch frequencies and ( A1 - A2) splittings of [P. Dréan, J.-M. Colmont, J. Demaison, L. Dore, C. Degli Esposti, J. Mol. Spectrosc. 176 (1996) 23-27]). A good fit was obtained by varying 15 molecular parameters characterizing the torsion-rotation Hamiltonian HTR for the vibrational ground state. Because of the strong correlation between two of the quartic torsion-distortion parameters ( F0,3 K and D0, Km) and a redundancy connecting the centrifugal distortion constants, four models were obtained yielding comparable fits. In each case, effective values were determined for the A-rotational constant and the height of the potential hindering the internal rotation. A high precision determination of the structural parameter ρ was made that is the same in all four models. For the off-diagonal quartic centrifugal distortion constant ɛ0 and the sextic constants H0, J, H0, JK, H0, KJ, and h0,3, the differences in the values obtained in the two different reductions used have been explained in terms of the redundancy connecting these parameters. For σ = 0, +1, -1, the energy level pattern for (| k| = 3) is discussed for the case where the pure torsional energy splitting and

  7. Nuclear rotation in the continuum

    NASA Astrophysics Data System (ADS)

    Fossez, K.; Nazarewicz, W.; Jaganathen, Y.; Michel, N.; Płoszajczak, M.

    2016-01-01

    Background: Atomic nuclei often exhibit collective rotational-like behavior in highly excited states, well above the particle emission threshold. What determines the existence of collective motion in the continuum region is not fully understood. Purpose: In this work, by studying the collective rotation of the positive-parity deformed configurations of the one-neutron halo nucleus 11Be, we assess different mechanisms that stabilize collective behavior beyond the limits of particle stability. Method: To solve a particle-plus-core problem, we employ a nonadiabatic coupled-channel formalism and the Berggren single-particle ensemble, which explicitly contains bound states, narrow resonances, and the scattering continuum. We study the valence-neutron density in the intrinsic rotor frame to assess the validity of the adiabatic approach as the excitation energy increases. Results: We demonstrate that collective rotation of the ground band of 11Be is stabilized by (i) the fact that the ℓ =0 one-neutron decay channel is closed, and (ii) the angular momentum alignment, which increases the parentage of high-ℓ components at high spins; both effects act in concert to decrease decay widths of ground-state band members. This is not the case for higher-lying states of 11Be, where the ℓ =0 neutron-decay channel is open and often dominates. Conclusion: We demonstrate that long-lived collective states can exist at high excitation energy in weakly bound neutron drip-line nuclei such as 11Be.

  8. Passive Rotation Range of Motion and Shoulder Subluxation: A Comparative Study

    PubMed Central

    Stanish, William; Kozey, Cheryl

    2009-01-01

    Background Conflicting reports of range of motion (ROM) findings exist related to shoulder instability. Knowledge of range of motion findings among individuals with shoulder subluxation may aid in diagnosis and facilitate appropriate management. Purpose The purpose of this study was to compare passive rotation ROM and determine if a symptom-provoking activity alters ROM between patients with shoulder subluxations and healthy controls. Methods Seventeen symptomatic patients with shoulder subluxations and 14 healthy controls between the ages of 18 and 35 years were recruited. Lateral and medial rotation ROM measures were taken using a universal goniometer. Symptoms were assessed using a 10cm visual analog scale (VAS). Each group performed a symptom-provoking activity, and VAS and ROM measures were repeated. Results A two-factor analysis of variance with repeated measures on pre/post activity demonstrated lower medial rotation measures for the instability group, but no differences for lateral rotation or total range (p < 0.05). A “warm-up” effect was noted, with greater ROM found in each group post activity, with a greater increase noted among controls. Analysis of the ratio of lateral rotation to medial rotation ROM found a significantly greater ratio in the instability group. VAS pain scores were greater in the instability group. Conclusion Shoulder subluxation is not necessarily associated with increased rotation ROM, therefore total ROM findings should not be used to screen for instability. Imbalances in rotation ROM may be associated with symptomatic shoulder instability and may have implications for treatment. PMID:21509102

  9. Uncovering the cognitive processes underlying mental rotation: an eye-movement study.

    PubMed

    Xue, Jiguo; Li, Chunyong; Quan, Cheng; Lu, Yiming; Yue, Jingwei; Zhang, Chenggang

    2017-08-30

    Mental rotation is an important paradigm for spatial ability. Mental-rotation tasks are assumed to involve five or three sequential cognitive-processing states, though this has not been demonstrated experimentally. Here, we investigated how processing states alternate during mental-rotation tasks. Inference was carried out using an advanced statistical modelling and data-driven approach - a discriminative hidden Markov model (dHMM) trained using eye-movement data obtained from an experiment consisting of two different strategies: (I) mentally rotate the right-side figure to be aligned with the left-side figure and (II) mentally rotate the left-side figure to be aligned with the right-side figure. Eye movements were found to contain the necessary information for determining the processing strategy, and the dHMM that best fit our data segmented the mental-rotation process into three hidden states, which we termed encoding and searching, comparison, and searching on one-side pair. Additionally, we applied three classification methods, logistic regression, support vector model and dHMM, of which dHMM predicted the strategies with the highest accuracy (76.8%). Our study did confirm that there are differences in processing states between these two of mental-rotation strategies, and were consistent with the previous suggestion that mental rotation is discrete process that is accomplished in a piecemeal fashion.

  10. Unsteady Casson nanofluid flow over a rotating cone in a rotating frame filled with ferrous nanoparticles: A numerical study

    NASA Astrophysics Data System (ADS)

    Raju, C. S. K.; Sandeep, N.

    2017-01-01

    In this study, we investigated the momentum and heat transfer characteristics of Casson nanofluid flow over a rotating cone in a rotating frame filled with water based CoFe2O4 nano particles. Heat flux conditions and wall temperature conditions are very important in controlling of up and down heat transport phenomena's in industrial as well as engineering application. Resulting set of coupled nonlinear governing equations are solved numerically using Runge-Kutta based shooting technique. In graphical results we presented dual solutions for the prescribed wall temperature (PWT) and prescribed heat flux (PHF) cases. The effect of governing parameters on velocity and temperature fields along with the skin friction coefficient and the heat transfer rate are presented with the help of graphs and tables. Results indicate that the rising values of the volume fraction of ferro particles and buoyancy parameter have tendency to improve the skin friction coefficient as well as the heat transfer rate for both the prescribed wall temperature (PWT) and prescribed heat flux (PHF) cases.

  11. Evolution of pre-collective nuclei: Structural signatures near the drip lines

    SciTech Connect

    Casten, R.F.; Zamfir, N.V. ||

    1994-10-01

    Recent studies have shown that the phenomenology of single-magic and near-magic nuclei has universal characteristics analogous to those of collective nuclei and that, moreover, this phenomenology attaches smoothly to that describing collective nuclei. This has led to a number of new signatures of structure as well as to a new, tripartite, classification of nuclear structure that embraces the gamut of structures from magic, through pre-collective, to fully collective and rotational nuclei. Aside from the natural appeal of simple global correlations of collective observables, these results have particular significance for soon-to-be accessible exotic nuclei near the drip lines since they rely on only the simplest-to-obtain data, in particular, the energies of just the first two excited states, E(4{sub 1}{sup +}) and E(2{sub 1}{sup +}), of even-even nuclei, and the B(E2:2{sub 1}{sup +}{yields}0{sub 1}{sup +}) value. Indeed, without the need for more extensive level schemes, these basic data alone can reveal information about the goodness of seniority, about the validity of pair-addition mode relationships of adjacent even-even nuclei, about underlying shell structure (validity of magic numbers) and even about the shell model potential itself (e.g., the strengths of the l{center_dot} and l{sup 2} terms).

  12. Differentiation between antibodies to protamines and somatic nuclear antigens by means of a comparative fluorescence study on swollen nuclei of spermatozoa and somatic cells.

    PubMed

    Samuel, T

    1978-05-01

    The indirect immunofluorescence test on swollen nuclei of rat thymocytes, chicken red blood cells and human and salmon spermatozoa was found to be an easy and satisfactory method for the discrimination between antibodies to sperm-specific nuclear antigens and somatic nuclear antigens. This study shows that nuclear antibodies present in the sera of vasectomized men and in rabbit antisera to human protamines are directed against the human sperm-specific nuclear antigens (protamines), and that they may cross-react with salmon protamine. These sera do not react with somatic nuclear antigens. This comparative fluorescence study and a complement fixation study, performed with sera from diabetic patients, proved that the administration of insulin retard (protamine-zinc-insulin) may lead to the formation of antibodies to the fish protamine. These antibodies may reveal a weak cross reaction with human protamines. The results obtained in this study also prove that the nuclei of chicken red blood cells and human sperm do not contain, or contain very small amounts of, histone fraction H1, and that salmon sperm nuclei do not contain any of the histone fractions, and suggest that the nuclei of mature human spermatozoa contain smaller amounts of histones in comparison to somatic cell nuclei.

  13. Very large array faraday rotation studies of the coronal plasma

    NASA Astrophysics Data System (ADS)

    Kooi, Jason Earl

    Knowledge of the coronal magnetic field is crucial for understanding (1) the heating mechanism(s) of the solar corona, (2) the acceleration of the fast solar wind, and (3) the structure and dynamics of coronal mass ejections (CMEs). Observation of Faraday rotation (FR) is one of the best remote-sensing techniques for determining plasma properties in the corona and can provide information on the plasma structure of a CME shortly after launch, shedding light on the initiation process. I used the Karl G. Jansky Very Large Array (VLA) to make sensitive Faraday rotation measurements to investigate the general plasma structure of the corona, properties of coronal plasma inhomogeneities and waves, and transients associated with coronal mass ejections. To enhance my measurements of FR transients, I also developed an algorithm in the Common Astronomy Software Applications (CASA) package to mitigate ionospheric Faraday rotation. In August, 2011, I made FR observations at 5.0 and 6.1 GHz of the radio galaxy 3C 228 through the solar corona at heliocentric distances of 4.6-5.0 solar radii using the VLA. Observations at 5.0 GHz permit measurements deeper in the corona than previous VLA observations at 1.4 and 1.7 GHz. These FR observations provided unique information on the magnetic field in this region of the corona. My data on 3C 228 provide two lines of sight (separated by 46 arcseconds, 33,000 km in the corona). I detected three periods during which there appeared to be a difference in the Faraday rotation measure between these two closely spaced lines of sight, which I used to estimate coronal currents; these values (ranging from 2.6 to 4.1 GA) are several orders of magnitude below that which is necessary for significant coronal heating (assuming the Spitzer resistivity). I also used the data to determine upper limits (3.3 and 6.4 rad/m2 along the two lines of sight) on FR fluctuations caused by coronal waves. These upper limits are comparable to and, thus, not inconsistent

  14. Assessment of left and right ventricular rotational interdependence: A speckle tracking echocardiographic study.

    PubMed

    Alizadehasl, Azin; Sadeghpour, Anita; Hali, Reza; Bakhshandeh Abkenar, Hooman; Badano, Luigi

    2017-03-01

    We sought to investigate the possible interdependence of the left (LV) and right ventricular (RV) rotational mechanics. Although myocardial fiber architecture and the effect of various pathologic conditions on LV torsional mechanics have already been investigated through multiple studies using different methods, there is still a significant debate about the actual presence and functional significance of RV rotational mechanics. We perform a cross-sectional prospective study of 118 subjects, including 19 normal subjects (NS, 35±7 years), 34 patients with severe aortic stenosis (AS, 44±16 years), 26 patients with nonobstructive hypertrophic cardiomyopathies (HCM, 46±18), and 39 patients with nonischemic dilated cardiomyopathies (DCM, 39±13 years). LV and RV rotational parameters were measured using velocity vector imaging. Total LV and RV apical segment rotations as well as the rotation of the free wall of RV apex were measured separately. Interdependence of the LV and RV rotational mechanics was assessed using the Spearman rho test. Both LV (7.3°±4.1° in NS, 11°±4.6° in AS, 7.7°±5.2° in HCM, and 1.9°±2° in DCM, P=<.0001) and RV apexes (4.7°±2° in NS, 6.1°±4° in AS, 3.2°±3.7° in HCM, and 2.4°±3.6° in DCM, P=<.0001) rotated counterclockwise in all the four study groups. Interventricular apical rotation interdependence was stronger in the AS (Spearman rho [ρ]: .716; P=.000) and in the HCM (ρ: .395; P=.04) subgroups than in the NS (ρ: .26; P=.27) and DCM (ρ: .215; P=.18). In DCM patients, RV apex rotation appeared to be independent of LV rotation. RV free wall apical rotation was larger than its corresponding value for the total apical segments in all studied groups. This difference was significant only in the AS (P=.007). Our findings demonstrated a close correlation between RV and LV apical rotation parameters in different cardiac conditions as well as in normal subjects. However, in DCM patients, we also showed some independent

  15. Exotic phenomena in 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.

  16. Study of Swift/Bat Selected Low-luminosity Active Galactic Nuclei Observed with Suzaku

    NASA Astrophysics Data System (ADS)

    Kawamuro, Taiki; Ueda, Yoshihiro; Tazaki, Fumie; Terashima, Yuichi; Mushotzky, Richard

    2016-11-01

    We systematically analyze the broadband (0.5-200 keV) X-ray spectra of hard X-ray (>10 keV) selected local low-luminosity active galactic nuclei (LLAGNs) observed with Suzaku and Swift/BAT. The sample consists of 10 LLAGNs detected with Swift/BAT with intrinsic 14-195 keV luminosities smaller than 1042 erg s-1 available in the Suzaku archive, covering a wide range of the Eddington ratio from 10-5 to 10-2. The overall spectra can be reproduced with an absorbed cut-off power law, often accompanied by reflection components from distant cold matter, and/or optically thin thermal emission from the host galaxy. In all of the objects, relativistic reflection components from the innermost disk are not required. Eight objects show a significant narrow iron-Kα emission line. Comparing their observed equivalent widths with the predictions from the Monte-Carlo-based torus model by Ikeda et al. (2009), we constrain the column density in the equatorial plane to be {log} {N}{{H}}{{eq}}\\gt 22.7, or the torus half-opening angle θ oa < 70°. We infer that the Eddington ratio (λ Edd) is a key parameter that determines the torus structure of LLAGNs: the torus becomes large at λ Edd ≳ 2 × 10-4, whereas at lower accretion rates it is little developed. The luminosity correlation between the hard X-ray and mid-infrared (MIR) bands of the LLAGNs follows the same correlation as for more luminous AGNs. This implies that mechanisms other than AGN-heated dust are responsible for the MIR emission in low Eddington ratio LLAGNs.

  17. High-Resolution Magnetic Analyzer MAVR for the Study of Exotic Weakly-Bound Nuclei

    NASA Astrophysics Data System (ADS)

    Maslov, V. A.; Kazacha, V. I.; Kolesov, I. V.; Lukyanov, S. M.; Melnikov, V. N.; Osipov, N. F.; Penionzhkevich, Yu. E.; Skobelev, N. K.; Sobolev, Yu. G.; Voskoboinik, E. I.

    2015-11-01

    A project of the high-resolution magnetic analyzer MAVR is proposed. The analyzer will comprise new magnetic optical and detecting systems for separation and identification of reaction products in a wide range of masses (5-150) and charges (1-60). The magnetic optical system consists of the MSP-144 magnet and a doublet of quadrupole lenses. This will allow the solid angle of the spectrometer to be increased by an order of magnitude up to 30 msr. The magnetic analyzer will have a high momentum resolution (10-4) and high focal-plane dispersion (1.9 m). It will allow products of nuclear reactions at energies up to 30 MeV/nucleon to be detected with the charge resolution ~1/60. Implementation of the project is divided into two stages: conversion of the magnetic analyzer proper and construction of the nuclear reaction products identification system. The MULTI detecting system is being developed for the MAVR magnetic analyzer to allow detection of nuclear reaction products and their identification by charge Q, atomic number Z, and mass A with a high absolute accuracy. The identification will be performed by measuring the energy loss (ΔE), time of flight (TOF), and total kinetic energy (TKE) of reaction products. The particle trajectories in the analyzer will also be determined using the drift chamber developed jointly with GANIL. The MAVR analyzer will operate in both primary beams of heavy ions and beams of radioactive nuclei produced by the U400-U400M acceleration complex. It will also be used for measuring energy spectra of nuclear reaction products and as an energy monochromator.

  18. A Parametric Study of Erupting Flux Rope Rotation: Modeling the 'Cartwheel CME' on 9 April 2008

    NASA Technical Reports Server (NTRS)

    Kliem, B.; Toeroek, T.; Thompson, W. T.

    2012-01-01

    The rotation of erupting filaments in the solar corona is addressed through a parametric simulation study of unstable, rotating flux ropes in bipolar force-free initial equilibrium. The Lorentz force due to the external shear-field component and the relaxation of tension in the twisted field are the major contributors to the rotation in this model, while reconnection with the ambient field is of minor importance, due to the field's simple structure. In the low-beta corona, the rotation is not guided by the changing orientation of the vertical field component's polarity inversion line with height. The model yields strong initial rotations which saturate in the corona and differ qualitatively from the profile of rotation vs. height obtained in a recent simulation of an eruption without preexisting flux rope. Both major mechanisms writhe the flux rope axis, converting part of the initial twist helicity, and produce rotation profiles which, to a large part, are very similar within a range of shear-twist combinations. A difference lies in the tendency of twist-driven rotation to saturate at lower heights than shear-driven rotation. For parameters characteristic of the source regions of erupting filaments and coronal mass ejections, the shear field is found to be the dominant origin of rotations in the corona and to be required if the rotation reaches angles of order 90 degrees and higher; it dominates even if the twist exceeds the threshold of the helical kink instability. The contributions by shear and twist to the total rotation can be disentangled in the analysis of observations if the rotation and rise profiles are simultaneously compared with model calculations. The resulting twist estimate allows one to judge whether the helical kink instability occurred. This is demonstrated for the erupting prominence in the "Cartwheel CME" on 9 April 2008, which has shown a rotation of approximately 115 deg. up to a height of 1.5 Solar R above the photosphere. Out of a range of

  19. Transitional nuclei near shell closures

    SciTech Connect

    Mukherjee, G.

    2014-08-14

    High spin states in Bismuth and Thallium nuclei near the Z = 82 shell closure and Cesium nuclei near the N = 82 shell closure in A = 190 and A = 130 regions, respectively, have been experimentally investigated using heavy-ion fusion evaporation reaction and by detecting the gamma rays using the Indian National Gamma Array (INGA). Interesting shape properties in these transitional nuclei have been observed. The results were compared with the neighboring nuclei in these two regions. The total Routhian surface (TRS) calculations have been performed for a better understanding of the observed properties. In mass region A = 190, a change in shape from spherical to deformed has been observd around neutron number N = 112 for the Bi (Z = 83) isotopes with proton number above the magic gap Z = 82, whereas, the shape of Tl (Z = 81) isotopes with proton number below the magic gap Z = 82 remains stable as a function of neutron number. An important transition from aplanar to planar configuration of angular momentum vectors leading to the occurance of nuclar chirality and magnetic rotation, respectively, has been proposed for the unique parity πh{sub 11/2}⊗νh{sub 11/2} configuration in Cs isotopes in the mass region A ∼ 130 around neutron number N = 79. These results are in commensurate with the TRS calculations.

  20. Pulsar VLBI to Measure Cosmological Rotation and Study Pulsar Emission Regions

    NASA Astrophysics Data System (ADS)

    Gwinn, C. R.

    2009-08-01

    Pulsars are useful for measuring the rotation of the universe. Also, their emission regions provide interesting laboratories for plasma physics. I describe here how VLBI of pulsars, and the VSOP-2 spacecraft, can contribute to such studies.

  1. Identical high- K three-quasiparticle rotational bands

    NASA Astrophysics Data System (ADS)

    Kaur, Harjeet; Singh, Pardeep

    2016-12-01

    A comprehensive study of high- K three-quasiparticle rotational bands in odd- A nuclei indicates the similarity in γ -ray energies and dynamic moment of inertia Im^{(2)} . The extent of the identicality between the rotational bands is evaluated by using the energy factor method. For nuclei pairs exhibiting identical bands, the average relative change in the dynamic moment of inertia Im^{(2)} is also determined. The identical behaviour shown by these bands is attributed to the interplay of nuclear structure parameters: deformation and the pairing correlations. Also, experimental trend of the I(hbar) vs. hbar ω (MeV) plot for these nuclei pairs is shown to be in agreement with Tilted-Axis Cranking (TAC) model calculations.

  2. Properties of nuclei in the nobelium region studied within the covariant, Skyrme, and Gogny energy density functionals

    DOE PAGES

    Dobaczewski, J.; Afanasjev, A. V.; Bender, M.; ...

    2015-07-29

    In this study, we calculate properties of the ground and excited states of nuclei in the nobelium region for proton and neutron numbers of 92 ≤ Z ≤ 104 and 144 ≤ N ≤ 156, respectively. We use three different energy-density-functional (EDF) approaches, based on covariant, Skyrme, and Gogny functionals, each with two different parameter sets. A comparative analysis of the results obtained for quasiparticle spectra, odd–even and two-particle mass staggering, and moments of inertia allows us to identify single-particle and shell effects that are characteristic to these different models and to illustrate possible systematic uncertainties related to using themore » EDF modelling.« less

  3. Generalized parton distributions in nuclei

    SciTech Connect

    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.

  4. Rotation Frequencies of Small Jovian Trojan Asteroids: An Excess of Slow Rotators

    NASA Astrophysics Data System (ADS)

    French, Linda M.; Stephens, Robert D.; James, David J.; Coley, Daniel; Connour, Kyle

    2015-11-01

    Several lines of evidence support a common origin for, and possible hereditary link between, cometary nuclei and jovian Trojan asteroids. Due to their distance and low albedos, few comet-sized Trojans have been studied. We discuss the rotation properties of Jovian Trojan asteroids less than 30 km in diameter. Approximately half the 131 objects discussed here were studied using densely sampled lightcurves (French et al. 2015a, b); Stephens et al. 2015), and the other half were sparse lightcurves obtained by the Palomar Transient Factory (PTF; Waszcazk et al. 2015).A significant fraction (~40%) of the objects in the ground-based sample rotate slowly (P > 24h), with measured periods as long as 375 h (Warner and Stephens 2011). The PTF data show a similar excess of slow rotators. Only 5 objects in the combined data set have rotation periods of less than six hours. Three of these fast rotators were contained in the data set of French et al. these three had a geometric mean rotation period of 5.29 hours. A prolate spheroid held together by gravity rotating with this period would have a critical density of 0.43 gm/cm3, a density similar to that of comets (Lamy et al. 2004).Harris et al. (2012) and Warner et al. (2011) have explored the possible effects on asteroid rotational statistics with the results from wide-field surveys. We will examine Trojan rotation statistics with and without the results from the PTF.

  5. Thermocapillary bubble flow and coalescence in a rotating cylinder: A 3D study

    NASA Astrophysics Data System (ADS)

    Alhendal, Yousuf; Turan, A.; Al-mazidi, M.

    2015-12-01

    The process of thermocapillary bubbles rising in a rotating 3D cylinder in zero gravity was analysed and presented numerically with the aid of computational fluid dynamics (CFD) by means of the volume of fluid (VOF) method. Calculations were carried out to investigate in detail the effect of the rotational speed of the hosted liquid on the trajectory of both single and group bubbles driven by the Marangoni force in zero-gravity conditions. For rotational speeds from 0.25 to 2 rad/s, bubble displacement with angular motion was found to be directed between the hotter surface and the rotational axis. This is contrary to the conventional bubble flow from areas of high pressure to low pressure, radial direction, or from cold to hot regions, axial direction. The results demonstrate that for the ratio of rotational speeds to the thermocapillary bubble velocity larger than unity, the surface tension gradient is the dominant force and the bubble motion towards the hotter. On the other hand, for ratio less than 1, the bubble motion is dominated and is significantly affected by centrifugal force. As rotation speed increases, the amount of deflection increases and the Marangoni effect vanishes. The current study is novel in the sense that single- and multi-bubble motion incorporating thermocapillary forces in a rotating liquid in a zero-gravity environment has never been numerically investigated.

  6. Shoulder rotators electro-mechanical properties change with intensive volleyball practice: a pilot study.

    PubMed

    Cornu, C; Nordez, A; Bideau, B

    2009-12-01

    This pilot study was designed to assess the incidence of high-level volleyball practice on muscle strength production and muscle activation during internal and external shoulder rotations. Seven professional and seven French amateur league volleyball players performed maximal isometric at three forearm angles, concentric and eccentric isokinetic internal and external shoulder rotations. The torque production and muscle activation levels of PECTORALIS MAJOR and INFRASPINATUS were determined. Few significant differences were found for muscle activation and co-activation between amateur and professional volleyball players during both internal and external rotations. No significant difference in torque production was observed for shoulder internal rotation between professional and amateur volleyball players. Torque production was significantly higher during shoulder external rotation for amateur (46.58+/-2.62 N . m) compared to professional (35.35+/-1.17 N . m) volleyball players relative to isometric contractions, but it was not different during isokinetic efforts. The torque ratios for external/internal rotations were always significantly lower for professional (0.42+/-0.03 pooling isometric and concentric conditions) compared to amateur volleyball players (0.56+/-0.03 pooling isometric and concentric conditions). Those results emphasize that a high level of volleyball practice induces a strong external rotators deficit compared to sports such as swimming, baseball or tennis.

  7. Rotational dynamics of confined C60 from near-infrared Raman studies under high pressure.

    PubMed

    Zou, Yonggang; Liu, Bingbing; Wang, Liancheng; Liu, Dedi; Yu, Shidan; Wang, Peng; Wang, Tianyi; Yao, Mingguang; Li, Quanjun; Zou, Bo; Cui, Tian; Zou, Guangtian; Wågberg, Thomas; Sundqvist, Bertil; Mao, Ho-Kwang

    2009-12-29

    Peapods present a model system for studying the properties of dimensionally constrained crystal structures, whose dynamical properties are very important. We have recently studied the rotational dynamics of C(60) molecules confined inside single walled carbon nanotube (SWNT) by analyzing the intermediate frequency mode lattice vibrations using near-infrared Raman spectroscopy. The rotation of C(60) was tuned to a known state by applying high pressure, at which condition C(60) first forms dimers at low pressure and then forms a single-chain, nonrotating, polymer structure at high pressure. In the latter state the molecules form chains with a 2-fold symmetry. We propose that the C(60) molecules in SWNT exhibit an unusual type of ratcheted rotation due to the interaction between C(60) and SWNT in the "hexagon orientation," and the characteristic vibrations of ratcheted rotation becomes more obvious with decreasing temperature.

  8. Tibial rotation influences anterior knee stability--a robot-aided in-vitro study.

    PubMed

    Lorenz, Andrea; Röttgerkamp, Heike; Bobrowitsch, Evgenij; Leichtle, Carmen I; Leichtle, Ulf G

    2016-02-01

    Anterior cruciate ligament rupture can lead to symptomatic instability, especially during pivoting activities, which are often associated with increased anterior and rotational tibial loading. Therefore, the purpose of our robot-aided in-vitro study was to analyze the influence of tibial rotation on anterior knee stability under three anterior cruciate ligament conditions. Ten human knee specimens were examined using a robotic system. Anterior tibial translations were measured during anterior force application at internally and externally rotated positions of the tibia (5° steps until 4 Nm was reached) at 20°, 60°, and 90° of flexion. The native knee was compared with the knee with deficient and replaced anterior cruciate ligament. Tibial rotation significantly influenced anterior tibial translation (P<0.001), with differences of up to 12 mm between the largest and smallest anterior translation in the deficient knee. The largest influence of the anterior cruciate ligament on anterior translation was found in slightly externally rotated positions of the tibia (5°-10° at 20° of flexion; 0°-5° at 90° of flexion). Significantly increased anterior tibial translation (up to 7 mm) was measured after anterior cruciate ligament resection, which could be almost completely restored by the replacement (remaining difference<1mm) over a wide range of tibial rotations. Tibial rotation clearly influences anterior tibial translation. Because the greatest effect of the anterior cruciate ligament was found in slightly externally rotated positions of the tibia, increased attention to tibial rotation should be paid when performing the Lachman and anterior drawer tests. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Prognostic factors for recovery after arthroscopic rotator cuff repair: a prognostic study.

    PubMed

    Fermont, Anouk J; Wolterbeek, Nienke; Wessel, Ronald N; Baeyens, Jean-Pierre; de Bie, Rob A

    2015-08-01

    Studies concerning prognostic factors of recovery after arthroscopic rotator cuff repair mostly focus on tendon integrity or functional recovery as an outcome. Little is known about how they influence quality of life after surgery. We therefore tried to identify prognostic factors having an impact on quality of life after arthroscopic rotator cuff repair. This study included 30 patients who underwent arthroscopic rotator cuff repair. We assessed Western Ontario Rotator Cuff Index as primary outcome and RAND-36, Constant-Murley score, and a shoulder hindrance score as secondary outcomes. Patients were repeatedly measured: once preoperatively and 4 times postoperatively. Preoperative range of motion, obesity, fatty infiltration, and cuff retraction were preselected as prognostic factors. Patients were significantly improved at 3 months and 6 months after arthroscopic rotator cuff repair. In multiple regression analysis, none of the preselected factors could be identified as a prognostic factor influencing quality of life after arthroscopic rotator cuff repair (measured with the Western Ontario Rotator Cuff Index). For the outcome variables RAND-36 (6 months, 1 year) and shoulder hindrance score (1 year), fatty infiltration Goutallier stages 1 and 2 and retraction grades II, III, and IV were significant predictors. Although fatty infiltration and retraction grade predict the RAND-36 and shoulder hindrance score, this study could not support preoperative range of motion, obesity, fatty infiltration, or retraction of the cuff as a prognostic factor for quality of life after arthroscopic rotator cuff repair. This study shows that if selection of patients is done properly, these factors do not influence a successful outcome. Copyright © 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

  10. Demonstration of topographically organized projections from the hypothalamus to the pontine nuclei: an experimental anatomical study in the cat.

    PubMed

    Aas, J E; Brodal, P

    1988-02-15

    In 22 cats implantations and injections of horseradish peroxidase-wheat germ agglutinin (HRP-WGA) or Fluoro-Gold were placed in the pontine nuclei or the hypothalamus. The occurrence and distribution of labeled cells in the hypothalamus and of labeled terminal fibers in the pontine nuclei were mapped. Following implantations of HRP-WGA ventromedially in rostral parts of the pontine nuclei, 22-44% of all labeled cells in the brainstem and diencephalon are found in the medial mamillary nucleus ipsilateral to the implantation. Some labeled cells are also found in the supramamillary, premamillary, anterior mamillary, and tuberomamillary nuclei. Thus, labeled cells in the hypothalamus make up 33-54% of all labeled cells in the brainstem and diencephalon in such cases. In contrast, implantations and injections in mediocaudal parts of the pontine nuclei result in labeling of cells mainly in the posterior, dorsal, and lateral hypothalamic areas (terminology of Bleier: The Hypothalamus of the Cat. Baltimore: Johns Hopkins Press, '61). In these cases the labeled cells in the hypothalamus make up 16-25% of all labeled cells in the brainstem and diencephalon. Implantations in more lateral parts of the pontine nuclei label only a few cells in the hypothalamus. Following implantations of HRP-WGA in restricted parts of the hypothalamus, fibers from the medial mamillary nucleus were found to terminate ventromedially at all rostrocaudal levels of the pontine nuclei, ipsilateral to the implantation. In the rostralmost part of the pontine nuclei, the terminal labeling forms a dense, transversely oriented, c-shaped band. Fibers from the posterior and dorsal hypothalamic areas terminate medially and dorsomedially in the caudal third of the pontine nuclei. Sparse terminal labeling is also seen in lateral parts of the pontine nuclei and medially at more rostral levels. In two cases with small implantations of HRP-WGA ventromedially in rostral parts of the pontine nuclei, labeled cells

  11. Elastic dipole response of spherical nuclei

    SciTech Connect

    Bastrukov, S.I.

    1992-10-01

    Within the framework of the nuclear fluid-dynamics the isoscalar dipole response of spherical nuclei is studied. Two kinds of elastic-like transverse oscillations of incompressible nucleus are found to be result in E1, T = 0 and M1, T = 0 spin-independent resonances. The isoscalar electric mode is accompanied by excitation in the nucleus volume of the torus-like current structure, known in the continuum theory as a poloidal dipole or spherical vortex of Hill. The dipole magnetic resonance belongs to the excitation of axially symmetric differential rotations. These motions are described by the toroidal dipole field harmonic in time. The estimates of energies and PWBA-computed form-factors for these modes are presented. 28 refs., 3 figs.

  12. Muon spin rotation studies of the metallic alkali fullerides

    NASA Astrophysics Data System (ADS)

    Macfarlane, William Andrew

    1998-11-01

    Results of muon spin rotation (/mu[/cal SR]) in the metallic intercalated C60 compounds (AnC60, where An are n alkali metal atoms) are presented. Except for the case of K1C60, the metallic state of these systems is unstable at low temperature (to a superconducting transition in A3C60 and a magnetic metal insulator transition in A1C60). In A3C60, the properties of the metallic and superconducting states are investigated using (i) diamagnetic muons to probe the distribution of internal magnetic field and (ii) paramagnetic muonium (Mu) trapped within the C60 cage to probe the electronic excitations. Mu is found to exhibit strong T1 relaxation due to its interaction with the conduction electrons. In the superconducting state this relaxation rate exhibits a small enhancement (Hebel-Slichter coherence peak) which possesses an anomalously strong magnetic field suppression. Exponential temperature dependence of the relaxation rate at low reduced temperature is observed, and from this estimates of the superconducting energy gap are obtained. At very low reduced temperature, deviations from this behaviour are found. Estimates of the magnetic penetration depth from broadening of the diamagnetic precession signal in the vortex state are also presented and discussed. In A1C60 (A = Rb and Cs), the magnetic state is investigated with zero field /mu[/cal SR]. Observation of a small rapidly damped oscillation below 2K in Cs1C60 is the first evidence from /mu[/cal SR] of magnetic order in these materials. The relaxation at higher temperature indicates that the internal fields are static and possess a broad distribution, indicating a highly disordered static magnetic structure. From the magnitude of the zero field relaxation rates, estimates of the magnitude of the internal field are made.

  13. Prevalence of symptomatic rotator cuff ruptures after shoulder trauma: a prospective cohort study.

    PubMed

    Valkering, Kars P; Stokman, Remco D; Bijlsma, Taco S; Brohet, Richard M; van Noort, Arthur

    2014-10-01

    After shoulder trauma, most fractures and dislocations are easily recognized on radiographic examination; however, the opposite is true for rotator cuff injuries. As a consequence, shoulder complaints may persist or arise due to unrecognized cuff injury. The objective of this study was to investigate the prevalence of shoulder pain and symptomatic rotator cuff ruptures 1 year after shoulder trauma without fracture or dislocation. This prospective descriptive study included all the patients presented at our emergency department between January 2007 and January 2008 after a trauma to the shoulder without fracture or dislocation. One year after trauma, this cohort was interviewed by telephone and re-examined at the outpatient clinic on indication. Of the 217 patients included, all had been pain-free before the trauma. One year after trauma, 69 patients (32%) were still suffering from shoulder pain. Of these patients, 31 were re-examined and 27 had already been re-examined in the meantime. In total, 20 of these 58 patients (34%) were diagnosed with a symptomatic rotator cuff rupture, representing a prevalence of 9% among the included patients. Emergency physicians should be aware that normal radiography does not exclude the presence of a rotator cuff tear in patients with a history of shoulder trauma. Regular follow-up is essential for discovering rotator cuff injuries. In this study, 32% still suffered from shoulder pain 1 year after shoulder trauma, and re-examination revealed a prevalence of 9% symptomatic rotator cuff ruptures.

  14. Effect of tamoxifen on fatty degeneration and atrophy of rotator cuff muscles in chronic rotator cuff tear: An animal model study.

    PubMed

    Cho, Edward; Zhang, Yue; Pruznak, Anne; Kim, H Mike

    2015-12-01

    Fatty degeneration of the rotator cuff muscles is an irreversible change resulting from chronic rotator cuff tear and is associated with poor clinical outcomes following rotator cuff repair. We evaluated the effect of Tamoxifen, a competitive estrogen receptor inhibitor, on fatty degeneration using a mouse model for chronic rotator cuff tear. Sixteen adult mice were divided into two diet groups (Tamoxifen vs. Regular) and subjected to surgical creation of a large rotator cuff tear and suprascapular nerve transection in their left shoulder with the right shoulder serving as a control. The rotator cuff muscles were harvested at 16 weeks and subjected to histology and RT-PCR for adipogenic and myogenic markers. Histology showed substantially decreased atrophy and endomysial inflammation in Tamoxifen group, but no significant differences in the amount of intramuscular adipocytes and lipid droplets compared to the Regular group. With RT-PCR, the operated shoulders showed significant upregulation of myogenin and PPAR-γ, and downregulation of myostatin compared to the nonsurgical shoulder. No significant differences of gene expression were found between the two diet groups. Our study demonstrated that tamoxifen diet leads to decreased muscle atrophy and inflammatory changes following chronic rotator cuff tear, but has no apparent effect on adipogenesis. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  15. Study of nuclei by means of the (p,2p) and (p,np) reactions at proton energy 1 GeV

    SciTech Connect

    Belostotskii, S.L.; Volkov, S.S.; Vorob'ev, A.A.; Dotsenko, Y.V.; Kudin, L.G.; Kuropatkin, N.P.; Miklukho, O.V.; Nikulin, V.N.; Prokof'ev, O.E.

    1985-06-01

    A missing-mass correlation spectrometer with resolution 4 MeV (FWHM) has been used to study the (p,2p) and (p,np) reaction at a proton energy T0 = 1.0 GeV in the nuclei WLi, XLi, ZBe, B, B, SC, and WO. The separation-energy spectra and the relative probabilities of knockout of protons and neutrons from the S and P shells are analyzed. The relation between the data obtained and the spatial distribution of protons and neutrons in the nuclei is discussed.

  16. Systematic Features of the Doubly-Even N=90 Nuclei: Detailed Experimental Study of a Collective Transition Region.

    NASA Astrophysics Data System (ADS)

    Kulp, W. D.; Wood, J. L.; Garrett, P. E.

    2004-10-01

    The N=90 region has long been a focus of collective nuclear model investigations. We report on a program of study which involves both systematic investigations (of ^150Nd, ^152Sm, ^154Gd, and ^156Dy to date) and multi-spectroscopy investigations (radioactive decay, (n,n'γ), (α, 2nγ) and multi-Coulex) of ^152Sm. These studies provide both ``horizontal'' and ``vertical'' extensions of our spectroscopic knowledge of these widely-studied nuclei. We report on the identification of the systematic occurrence of a low-energy 0^+ ``pairing isomer'' band [1], a K^π = 2^+ ``βγ'' band, a ``hexadecapole'' band, and a broad family of ``octupole'' bands. The radioactive decay studies have been done using the 8π spectrometer (both at LBNL and TRIUMF-ISAC). The multi-Coulex studies have been made using Gammasphere-CHICO (at LBNL). The (α, 2nγ) studies have been carried out at the University of Cologne tandem. The (n,n'γ) studies were made at the University of Kentucky Van de Graaff. [1] W. D. Kulp et al., Phys. Rev. Lett. 91, 102501 (2003).

  17. Interplay between one-particle and collective degrees of freedom in nuclei

    NASA Astrophysics Data System (ADS)

    Hamamoto, Ikuko

    2016-02-01

    Some developments of nuclear-structure physics uniquely related to Copenhagen School are sketched based on theoretical considerations versus experimental findings and one-particle versus collective aspects. Based on my personal overview I pick up the following topics; (1) Study of vibration in terms of particle-vibration coupling; (2) one-particle motion in deformed and rotating potentials, and yrast spectroscopy in high-spin physics; (3) triaxial shape in nuclei: wobbling motion and chiral bands; (4) nuclear structure of drip line nuclei: in particular, shell-structure (or magic numbers) change and spherical or deformed halo phenomena; (5) shell structure in oblate deformation.

  18. Brownian motion studies of viscoelastic colloidal gels by rotational single particle tracking

    DOE PAGES

    Liang, Mengning; Harder, Ross; Robinson, Ian K.

    2014-04-14

    Colloidal gels have unique properties due to a complex microstructure which forms into an extended network. Although the bulk properties of colloidal gels have been studied, there has been difficulty correlating those properties with individual colloidal dynamics on the microscale due to the very high viscosity and elasticity of the material. We utilize rotational X-ray tracking (RXT) to investigate the rotational motion of component crystalline colloidal particles in a colloidal gel of alumina and decanoic acid. Our investigation has determined that the high elasticity of the bulk is echoed by a high elasticity experienced by individual colloidal particles themselves butmore » also finds an unexpected high degree of rotational diffusion, indicating a large degree of freedom in the rotational motion of individual colloids even within a tightly bound system.« less

  19. Elbow joint stability in relation to forced external rotation: An experimental study of the osseous constraint.

    PubMed

    Deutch, Søren R; Jensen, Steen L; Olsen, Bo S; Sneppen, Otto

    2003-01-01

    The objective of this study was to evaluate the osseous constraint related to forced forearm external rotation as the initial stage in a posterior elbow dislocation. Six joint specimens without soft tissues were examined in a joint analysis system developed for simulation of dislocation. The osseous stability, expressed as the maximal torque needed for pathologic external forearm rotation, increased from varus to valgus stress (P =.0001) and from 10 degrees to 90 degrees of elbow flexion (P =.012) and also tended to increase from forearm supination to pronation. The work of pathologic external forearm rotation until the point of maximal torque decreased from a maximum in full extension to a minimum at 30 degrees of elbow flexion (P =.03). The elbow in a slightly flexed position, varus stress, and forearm external rotation trauma might be the important biomechanical factors in the posterior elbow dislocation, and they might serve as guidelines during clinical investigation for posterolateral instability.

  20. Brownian motion studies of viscoelastic colloidal gels by rotational single particle tracking

    PubMed Central

    Liang, Mengning; Harder, Ross; Robinson, Ian K.

    2014-01-01

    Colloidal gels have unique properties due to a complex microstructure which forms into an extended network. Although the bulk properties of colloidal gels have been studied, there has been difficulty correlating those properties with individual colloidal dynamics on the microscale due to the very high viscosity and elasticity of the material. We utilize rotational X-ray tracking (RXT) to investigate the rotational motion of component crystalline colloidal particles in a colloidal gel of alumina and decanoic acid. Our investigation has determined that the high elasticity of the bulk is echoed by a high elasticity experienced by individual colloidal particles themselves but also finds an unexpected high degree of rotational diffusion, indicating a large degree of freedom in the rotational motion of individual colloids even within a tightly bound system. PMID:25075336

  1. Electroproduction of Strange Nuclei

    SciTech Connect

    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.

  2. Assigning {gamma} deformation from fine structure in exotic nuclei

    SciTech Connect

    Ferreira, L. S.; Maglione, E.; Arumugam, P.

    2011-10-28

    The nonadiabatic quasiparticle model for triaxial shapes is used to perform calculations for decay of {sup 141}Ho, the only known odd-Z even-N deformed nucleus for which fine structure in proton emission from both ground and isomeric states has been observed. All experimental data corresponding to this unique case namely, the rotational spectra of parent and daughter nuclei, decay widths and branching ratios for ground and isomeric states, could be well explained with a strong triaxial deformation {gamma}{approx}20. The recent experimental observation of fine structure decay from the isomeric state, can be explained only with an assignment of I{sup {pi}} = 3/2{sup +} as the decaying state, in contradiction with the previous assignment, of I{sup {pi}} 1/2{sup +}, based on adiabatic calculations. This study reveals that proton emission measurements could be a precise tool to probe triaxial deformations and other structural properties of exotic nuclei beyond the proton dripline.

  3. Automatic track following system to study double strangeness nuclei in nuclear emulsion exposed to the observable limit

    NASA Astrophysics Data System (ADS)

    Myint Kyaw Soe; Goto, Ryosuke; Mishina, Akihiro; Nakanisi, Yoshiaki; Nakashima, Daisuke; Yoshida, Junya; Nakazawa, Kazuma

    2017-03-01

    An automatic track following system has been successfully developed to follow tracks in nuclear emulsion sheets exposed with beam up to the limit to be observed for the first time. The track followed rate of the system is 99.5% with the assistance of the new techniques. The working speed for a track is less than 1 min through one thick emulsion sheet, whereas it is 15 times faster than that of semiautomatic system with human. The system working for 24 h is applied for the E07 experiment at J-PARC and makes it possible to detect 102 nuclei with double strangeness (S=-2 nuclei) within one year. Regarding analyses to identify nuclear species of S=-2 nuclei, the system shows quite decent job for significant steps such as following tracks emitted to spherical directions from S=-2 nuclei, measurement of lengths of followed tracks, and so on.

  4. Arthroscopic vs mini-open rotator cuff repair. A quality of life impairment study

    PubMed Central

    Osti, Leonardo; Papalia, Rocco; Paganelli, Massimo; Denaro, Enzo

    2009-01-01

    We compared the clinical and quality of life related outcome of rotator cuff repair performed using either a mini-open or an arthroscopic technique for rotator cuff tears of less than 3 cm. The records of 64 patients who underwent rotator cuff repair between September 2003 and September 2005 were evaluated. Thirty-two patients underwent a mini-open rotator cuff repair, and 32 patients underwent an arthroscopic rotator cuff repair. The mean follow-up period was 31 months in the mini-open group and 30.6 months in the arthroscopic group (P > 0.05). The UCLA rating system, range of motion examination and the self-administered SF-36 used for postoperative evaluation showed a statistically significant improvement from the preoperative to the final score for both groups (P < 0.05). No statistically significant difference in the total UCLA scores was found when comparing the two repair techniques (P > 0.05). This study suggests that there is no difference in terms of subjective and objective outcomes between the two surgical procedures studied if patients have rotator cuff tears of less than 3 cm. PMID:19424692

  5. Arthroscopic vs mini-open rotator cuff repair. A quality of life impairment study.

    PubMed

    Osti, Leonardo; Papalia, Rocco; Paganelli, Massimo; Denaro, Enzo; Maffulli, Nicola

    2010-03-01

    We compared the clinical and quality of life related outcome of rotator cuff repair performed using either a mini-open or an arthroscopic technique for rotator cuff tears of less than 3 cm. The records of 64 patients who underwent rotator cuff repair between September 2003 and September 2005 were evaluated. Thirty-two patients underwent a mini-open rotator cuff repair, and 32 patients underwent an arthroscopic rotator cuff repair. The mean follow-up period was 31 months in the mini-open group and 30.6 months in the arthroscopic group (P > 0.05). The UCLA rating system, range of motion examination and the self-administered SF-36 used for postoperative evaluation showed a statistically significant improvement from the preoperative to the final score for both groups (P < 0.05). No statistically significant difference in the total UCLA scores was found when comparing the two repair techniques (P > 0.05). This study suggests that there is no difference in terms of subjective and objective outcomes between the two surgical procedures studied if patients have rotator cuff tears of less than 3 cm.

  6. Spectral characterization and differential rotation study of active CoRoT stars

    NASA Astrophysics Data System (ADS)

    Nagel, E.; Czesla, S.; Schmitt, J. H. M. M.

    2016-05-01

    The CoRoT space telescope observed nearly 160 000 light curves. Among the most outstanding is that of the young, active planet host star CoRoT-2A. In addition to deep planetary transits, the light curve of CoRoT-2A shows strong rotational variability and a superimposed beating pattern. To study the stars that produce such an intriguing pattern of photometric variability, we identified a sample of eight stars with rotation periods between 0.8 and 11 days and photometric variability amplitudes of up to 7.5%, showing a similar CoRoT light curve. We also obtained high-resolution follow-up spectroscopy with TNG/SARG and carried out a spectral analysis with SME and MOOG. We find that the color dependence of the light curves is consistent with rotational modulation due to starspots and that latitudinal differential rotation provides a viable explanation for the light curves, although starspot evolution is also expected to play an important role. Our MOOG and SME spectral analyses provide consistent results, showing that the targets are dwarf stars with spectral types between F and mid-K. Detectable Li i absorption in four of the targets confirms a low age of 100-400 Myr also deduced from gyrochronology. Our study indicates that the photometric beating phenomenon is likely attributable to differential rotation in fast-rotating stars with outer convection zones.

  7. Are ligament-tensioning devices interchangeable? A study of femoral rotation.

    PubMed

    Basselot, F; Gicquel, T; Common, H; Hervé, A; Berton, E; Ropars, M; Huten, D

    2016-06-01

    During total knee arthroplasty (TKA), femoral rotation can be adjusted either in relation to bony landmarks or by tensioning the ligaments with the knee in 90° of flexion. The primary objective of this study was to compare femoral rotations achieved using various ligament-tensioning devices. The secondary objective was to compare these femoral rotations to that indicated by the transepicondylar axis (TEA). We performed 13 posterior-stabilised TKA procedures using HiFit (Ceraver(®)) on cadaver knees. Before performing the posterior condyle cut, we used an original method to measure the femoral rotation induced by five different ligament-tensioning devices (2 with a ratchet mechanism, 1 with screws, 1 force-sensing device, and 1 with spacer blocks) and the central tibio-femoral distance (CTFD). Both ratchet tensioners provided significantly greater mean external rotation values (P=0.002), of 4.94° and 4.46°, respectively, compared to the force-sensing and spacer tensioners. Significant differences were found across devices for CTFD, with a mean difference of about 2mm between the ratchet and screw tensioners versus the force-sensing and spacer tensioners. The mean differences in rotations obtained using the tensioners versus the TEA were close to 0° but with standard deviations greater than 4°. Femoral rotation was dependent on the distraction force applied to the joint. Tensioners that did not measure the distraction force were associated with greater distraction force and external rotation values. The TEA criterion did not reliably indicate good ligament balance. Experimental study. Copyright © 2016. Published by Elsevier Masson SAS.

  8. Thickness of the Rotator Cuff Tendons at the Articular Margin: An Anatomic Cadaveric Study.

    PubMed

    Sessions, William C; Lawrence, Rebekah L; Steubs, J Tyler; Ludewig, Paula M; Braman, Jonathan P

    2017-01-01

    With a substantial portion of the population experiencing rotator cuff pathology, the importance of understanding mechanisms of rotator cuff disease remains critical. Current research aimed at understanding relationships between shoulder movement and cuff injuries has been hindered by our limited knowledge of the thickness of soft tissue structures within the shoulder. Therefore, the purpose of this study is to measure the thicknesses of all four rotator cuff tendons at the articular margin. An anatomic study of 21 cadaveric shoulders was conducted. The thicknesses of the four rotator cuff tendon insertions were measured by caliper at the articular margin. The mean thickness of the supraspinatus at the articular margin was 4.9 mm ± 2.1 (median: 4.2 mm, range: 2.9-12.7 mm). The mean thickness of the infraspinatus tendon was 4.9 mm ± 1.3 (median: 4.8 mm, range: 3.0-7.2 mm). The mean thickness of the teres minor tendon was 3.20 mm ± 1.14 (median: 2.9 mm, range: 1.7-5.7 mm). Finally, the mean thickness of the subscapularis tendon at the articular margin was 5.5 mm ± 1.3 (median: 5.5 mm, range: 3.5-9.3 mm). This current study provides needed objective data about the thickness of the rotator cuff tendons at the articular margin. Data regarding the infraspinatus, teres minor and teres major, which have been largely understudied, are particularly important. In addition, the current study demonstrates that rotator cuff thicknesses can vary substantially between individuals. There are likely natural age related changes as well as changes from etiologies that are not yet elucidated. Clinical Relevance: Data from this study will allow for improved modelling accuracy of soft tissue structures specific to the shoulder. Eventually knowledge gained through study of shoulder mechanics can be used to pursue prevention of rotator cuff tears and improve targeted treatment planning.

  9. Studies of yrast and continuum states in A=140-160 nuclei. Progress report, January 1, 1980-December 31, 1980. [Purdue Univ. , 1/1/80-12/31/80

    SciTech Connect

    Daly, P.J.

    1981-01-01

    The structure of nuclei in the A approx. 150 region was investigated by in-beam ..gamma..-ray spectroscopy using heavy-ion beams, mostly from the Argonne Tandem-Linac. Results for the nuclei /sup 148/Dy, /sup 149/Dy, /sup 153/Dy, /sup 154/Dy, /sup 149/Ho, and /sup 150/Ho are summarized. The feeding of yrast states in these nuclei and the link between the highest known yrast states and the continuum region were also studied. 6 figures.

  10. Function of the ligamentum teres in limiting hip rotation: a cadaveric study.

    PubMed

    Martin, Hal D; Hatem, Munif A; Kivlan, Benjamin R; Martin, RobRoy L

    2014-09-01

    The purpose of this cadaveric study was to evaluate the function of the ligamentum teres (LT) in limiting hip rotation in 18 distinct hip positions while preserving the capsular ligaments. Twelve hips in 6 fresh-frozen pelvis-to-toes cadaveric specimens were skeletonized from the lumbar spine to the distal femur, preserving only the hip ligaments. Hip joints were arthroscopically accessed through a portal located between the pubofemoral and iliofemoral ligaments to confirm the integrity of the LT. Three independent measurements of hip internal and external rotation range of motion (ROM) were performed in 18 defined hip positions of combined extension-flexion and abduction-adduction. The LT was then arthroscopically sectioned and rotation ROM reassessed in the same positions. A paired sample t test was used to compare the average internal and external hip rotation ROM values in the intact LT versus resected conditions in each of the 18 positions. P < .0014 was considered significant. A statistically significant influence of the LT on internal or external rotation was found in 8 of the 18 hip positions tested (P < .0014). The major increases in internal and external rotation ROM occurred when the hip was in 90° or 120° of flexion. The major function of the LT is controlling hip rotation. The LT functions as an end-range stabilizer to hip rotation dominantly at 90° or greater of hip flexion, confirming its contribution to hip stability. Ruptures of the LT contribute to hip instability dominantly in flexed hip positions. Copyright © 2014 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

  11. Critical care staff rotation: outcomes of a survey and pilot study.

    PubMed

    Richardson, Annette; Douglas, Margaret; Shuttler, Rachel; Hagland, Martin R

    2003-01-01

    Staff rotation is defined as a reciprocal exchange of staff between two or more clinical areas for a predetermined period of time. The rationale for introducing a 'Critical Care Nurse Rotation Programme' includes important issues such as improving nurses' knowledge and skills, providing development opportunities, networking, the ability to recruit and retain nurses and the provision of a more versatile and flexible workforce. To gain the understanding of nurses' views and opinions on critical care rotation programmes, evidence was collected by means of questionnaires involving 153 critical care nurses and by undertaking semi-structured interviews with four nurses. On the basis of the responses, a pilot of three Critical Care Nurse Rotation Programmes was introduced. An evaluation of the pilot project assessed participants, supervisors and senior nurses' experience of rotation and revealed very positive experiences being reported. The benefits highlighted included improving clinical skills and experience, improving interdepartmental relationships, heightened motivation and opportunities to network. The disadvantages focused on the operational and managerial issues, such as difficulties maintaining supervision and providing an adequate supernumerary period. Evidence from the survey and pilot study suggests that in the future, providing rotational programmes for critical care nurses would be a valuable strategy for recruitment, retention and developing the workforce.

  12. Tectonic rotations within the Rio Grande rift - Evidence from paleomagnetic studies

    NASA Technical Reports Server (NTRS)

    Brown, L. L.; Golombek, M. P.

    1985-01-01

    Paleomagnetic studies on Miocene Pliocene volcanic rocks from the Espanola basin of the Rio Grande rift, New Mexico, reveal directions discordant form the expected mean direction for North America. The Paliza Canyon Formation, Tschicoma Formation, and Lobato Basalt, all sampled in the Jemez Mountains west of the Pajarito fault zone, have mean declinations east of the expected mean. The Cerros del Rio volcanics, lying east of the Pajarito fault zone, have a westerly declination. Combined with published data on the Santa Fe Group sediments east of the fault zone, and the Valles Rhyolite, west of the fault zone, distinct rotations of the two areas are evident. The western block has rotated clockwise 12 deg, while the eastern block shows 16 deg of conter-clockwise motion. Differential rotations of 25-30 deg are calculated between the two blocks; 4 deg/m.y. is the minimum differential rotation for the past 5 m.y. Geologic explanations for these rotations include the opening of the Rio Grande rift in response to clockwise rotation of the Colorado Plateau and significant left slip along the Rio Grande rift.

  13. Circumnuclear ionized gas in starburst nuclei

    NASA Technical Reports Server (NTRS)

    Taniguchi, Yoshiaki

    1990-01-01

    In order to study kinematical properties of starburst nuclei (SBNs), researchers made high-resolution spectroscopy of fifteen SBNs in the H alpha region using an intensified Reticon system attached to the coude focus of the 188-cm reflector at the Okayama Astrophysical Observatory. The instrumental resolution is 21 km s(-1) Full Width Half Maximum (FWHM) at lambda sub H alpha. As for the archetypical SBN, Mrk 538 (=NGC 7714), researchers present high-resolution emission line profiles of several species of ions such as (OIII), (NII), (SII), and (OII). Main results and conclusions are summarized. It has been known that emission-line profiles of SBNs are symmetrical and narrow. However, this high-resolution spectroscopy shows that the observed emission-line profiles of the SBNs have the following asymmetrical patterns; blueward, redward, and double-peaked. It is known that such features have been observed for narrow line regions (NLRs) of active galactic nuclei (AGNs). There is no remarkable correlation between the asymmetry index and the reddening indicator such as a Balmer decrement. Thus the line asymmetry is not attributed to inhomogeneous obscuration in the emitting regions. The observed FWHMs of the H alpha emission lines cover a range from 85 km s(-1) to 318 km s(-1) and are slightly larger than those of (NII) lambda 6584A emission except for the double-peaked SBNs. The FWHMs of H alpha emission show a good correlation with sin i (i is an inclination angle of galaxy). This correlation means that the FWHMs of the SBNs suffer significantly from rotational broadening. Mrk 52 is an anomalous SBN because it has narrow emission line widths for its high inclination angle (cf. Taniguchi 1987). From the above correlation, it is estimated that the intrinsic (i.e., rotation free) FWHMs of H alpha emission are about 50 km s(-1).

  14. Circumnuclear ionized gas in starburst nuclei

    NASA Astrophysics Data System (ADS)

    Taniguchi, Yoshiaki

    1990-07-01

    In order to study kinematical properties of starburst nuclei (SBNs), researchers made high-resolution spectroscopy of fifteen SBNs in the H alpha region using an intensified Reticon system attached to the coude focus of the 188-cm reflector at the Okayama Astrophysical Observatory. The instrumental resolution is 21 km s(-1) Full Width Half Maximum (FWHM) at lambdaH alpha. As for the archetypical SBN, Mrk 538 (=NGC 7714), researchers present high-resolution emission line profiles of several species of ions such as (OIII), (NII), (SII), and (OII). Main results and conclusions are summarized. It has been known that emission-line profiles of SBNs are symmetrical and narrow. However, this high-resolution spectroscopy shows that the observed emission-line profiles of the SBNs have the following asymmetrical patterns; blueward, redward, and double-peaked. It is known that such features have been observed for narrow line regions (NLRs) of active galactic nuclei (AGNs). There is no remarkable correlation between the asymmetry index and the reddening indicator such as a Balmer decrement. Thus the line asymmetry is not attributed to inhomogeneous obscuration in the emitting regions. The observed FWHMs of the H alpha emission lines cover a range from 85 km s(-1) to 318 km s(-1) and are slightly larger than those of (NII) lambda 6584A emission except for the double-peaked SBNs. The FWHMs of H alpha emission show a good correlation with sin i (i is an inclination angle of galaxy). This correlation means that the FWHMs of the SBNs suffer significantly from rotational broadening. Mrk 52 is an anomalous SBN because it has narrow emission line widths for its high inclination angle (cf. Taniguchi 1987). From the above correlation, it is estimated that the intrinsic (i.e., rotation free) FWHMs of H alpha emission are about 50 km s(-1).

  15. Rotational elasticity

    NASA Astrophysics Data System (ADS)

    Vassiliev, Dmitri

    2017-04-01

    We consider an infinite three-dimensional elastic continuum whose material points experience no displacements, only rotations. This framework is a special case of the Cosserat theory of elasticity. Rotations of material points are described mathematically by attaching to each geometric point an orthonormal basis that gives a field of orthonormal bases called the coframe. As the dynamical variables (unknowns) of our theory, we choose the coframe and a density. We write down the general dynamic variational functional for our rotational theory of elasticity, assuming our material to be physically linear but the kinematic model geometrically nonlinear. Allowing geometric nonlinearity is natural when dealing with rotations because rotations in dimension three are inherently nonlinear (rotations about different axes do not commute) and because there is no reason to exclude from our study large rotations such as full turns. The main result of the talk is an explicit construction of a class of time-dependent solutions that we call plane wave solutions; these are travelling waves of rotations. The existence of such explicit closed-form solutions is a non-trivial fact given that our system of Euler-Lagrange equations is highly nonlinear. We also consider a special case of our rotational theory of elasticity which in the stationary setting (harmonic time dependence and arbitrary dependence on spatial coordinates) turns out to be equivalent to a pair of massless Dirac equations. The talk is based on the paper [1]. [1] C.G.Boehmer, R.J.Downes and D.Vassiliev, Rotational elasticity, Quarterly Journal of Mechanics and Applied Mathematics, 2011, vol. 64, p. 415-439. The paper is a heavily revised version of preprint https://arxiv.org/abs/1008.3833

  16. Properties of nuclei at high spins. [A = 160 to 166

    SciTech Connect

    Stephens, F.S.

    1982-10-01

    Nuclei generate high spins by two methods, alignment of single particle angular momentum and collective rotation. The competition of these two modes is discussed for the highest spins 40 less than or equal to I less than or equal to 65 h bar. Evidence is presented that alignment of the h/sub 9/2/ and i/sub 13/2/ proton orbitals from the next higher major shell produces large affects at high spins in rotational nuclei in the A = 160-166 region. It is suggested that such major shell effects produce the still larger irregularities known to occur in the lighter nuclei of this region.

  17. LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray D05

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray D05 EL-1994-00311 LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray D05 The postflight photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken in SAEF II at KSC after removal of the experiment tray from the LDEF. The experiment tray flanges appear discolored by a brown stain. Outlines of experiment tray clamp blocks are clearly visible on the upper and lower tray flanges. The experiment tray holding fixture hardware covers the clamp block areas on the end flanges. The UHCRE detectors were contained in 16 peripheral LDEF trays with at least one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar of a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. The copper colored strip extending over the trays lower flange is a copper coated pressure sensitive tape used to provide an electrical ground between the

  18. Three-dimensional speckle-tracking imaging for left ventricular rotation measurement: an in vitro validation study.

    PubMed

    Zhou, Zhiwen; Ashraf, Muhammad; Hu, Dayi; Dai, Xiaonan; Xu, Yawei; Kenny, Bill; Cameron, Berkley; Nguyen, Thuan; Xiong, Li; Sahn, David J

    2010-06-01

    Left ventricular (LV) twist is manifested in oppositely directed apical and basal rotation. We studied a new 3-dimensional (3D) echocardiography program (wall motion tracking; Toshiba America Medical Systems, Inc, Tustin, CA) for left ventricular rotation. We used a rotation model with a variable-speed motor to rotate hearts in a water bath. We studied 10 freshly harvested pig hearts, which were mounted on the rotary actuator of our twist phantom with the heart base rotating and the apex held fixed to avoid translational motion, at rotations of 0 degrees , 15 degrees , 20 degrees , and 25 degrees . Full-volume 3D image loops were acquired on a Toshiba Aplio Artida ultrasound system at a maximized frame rate. As the actual heart rotation increased, computed segmental and global rotation also increased accordingly, with the measured rotations of the basal and middle segments greater than that of the apex (both P < .001). Segmental and global rotation at all 3 levels correlated well with the actual rotation (base: r = 0.93; middle: r = 0.92; apex: r = 0.82; global: r = 0.95; all P < .001). The new 3D program tracked LV rotation accurately.

  19. A study on nuclear properties of Zr, Nb, and Ta nuclei used as structural material in fusion reactor

    NASA Astrophysics Data System (ADS)

    Sahan, Halide; Tel, Eyyup; Sahan, Muhittin; Aydin, Abdullah; Hakki Sarpun, Ismail; Kara, Ayhan; Doner, Mesut

    2015-07-01

    Fusion has a practically limitless fuel supply and is attractive as an energy source. The main goal of fusion research is to construct and operate an energy generating system. Fusion researches also contains fusion structural materials used fusion reactors. Material issues are very important for development of fusion reactors. Therefore, a wide range of fusion structural materials have been considered for fusion energy applications. Zirconium (Zr), Niobium (Nb) and Tantalum (Ta) containing alloys are important structural materials for fusion reactors and many other fields. Naturally Zr includes the 90Zr (%51.5), 91Zr (%11.2), 92Zr (%17.1), 94Zr (%17.4), 96Zr (%2.80) isotopes and 93Nb and 181Ta include the 93Nb (%100) and 181Ta (%99.98), respectively. In this study, the charge, mass, proton and neutron densities and the root-mean-square (rms) charge radii, rms nuclear mass radii, rms nuclear proton, and neutron radii have been calculated for 87-102Zr, 93Nb, 181Ta target nuclei isotopes by using the Hartree-Fock method with an effective Skyrme force with SKM*. The calculated results have been compared with those of the compiled experimental taken from Atomic Data and Nuclear Data Tables and theoretical values of other studies.

  20. The Role of Anterior Nuclei of the Thalamus: A Subcortical Gate in Memory Processing: An Intracerebral Recording Study

    PubMed Central

    Štillová, Klára; Jurák, Pavel; Chládek, Jan; Chrastina, Jan; Halámek, Josef; Bočková, Martina; Goldemundová, Sabina; Říha, Ivo; Rektor, Ivan

    2015-01-01

    Objective To study the involvement of the anterior nuclei of the thalamus (ANT) as compared to the involvement of the hippocampus in the processes of encoding and recognition during visual and verbal memory tasks. Methods We studied intracerebral recordings in patients with pharmacoresistent epilepsy who underwent deep brain stimulation (DBS) of the ANT with depth electrodes implanted bilaterally in the ANT and compared the results with epilepsy surgery candidates with depth electrodes implanted bilaterally in the hippocampus. We recorded the event-related potentials (ERPs) elicited by the visual and verbal memory encoding and recognition tasks. Results P300-like potentials were recorded in the hippocampus by visual and verbal memory encoding and recognition tasks and in the ANT by the visual encoding and visual and verbal recognition tasks. No significant ERPs were recorded during the verbal encoding task in the ANT. In the visual and verbal recognition tasks, the P300-like potentials in the ANT preceded the P300-like potentials in the hippocampus. Conclusions The ANT is a structure in the memory pathway that processes memory information before the hippocampus. We suggest that the ANT has a specific role in memory processes, especially memory recognition, and that memory disturbance should be considered in patients with ANT-DBS and in patients with ANT lesions. ANT is well positioned to serve as a subcortical gate for memory processing in cortical structures. PMID:26529407

  1. Large-Amplitude X-ray Outbursts from Galactic Nuclei: A Systematic Study Using ROSAT Archival Data

    NASA Astrophysics Data System (ADS)

    Donley, J.; Brandt, W. N.; Eracleous, Michael; Boller, Th.

    2001-05-01

    We present the results from a study designed to detect extragalactic large-amplitude X-ray outbursts using ROSAT archival data. Such outbursts are known to decay over a period of months to years, to have maximum X-ray luminosities of order 1043 to 1044 erg/s, and to often have very soft spectra. As such they are excellent ROSAT targets. By comparing different ROSAT observations, we have identified all galactic nuclei that (1) were in outburst during the six-month ROSAT All-Sky Survey and that (2) then faded by a minimum factor of 20 to low or undetectable count rates in later pointed ROSAT observations. The systematic nature of this study has allowed us to place the first reliable constraints on the number of such outbursts that occur in the Universe. We discuss these constraints and their implications for future missions such as MAXI and Lobster-eye X-ray telescopes. We also discuss possible mechanisms for the outbursts, the most likely of which is the tidal disruption of a star by a supermassive black hole.

  2. The role of mental rotation and memory scanning on the performance of laparoscopic skills: a study on the effect of camera rotational angle.

    PubMed

    Conrad, J; Shah, A H; Divino, C M; Schluender, S; Gurland, B; Shlasko, E; Szold, A

    2006-03-01

    The rotational angle of the laparoscopic image relative to the true horizon has an unknown influence on performance in laparoscopic procedures. This study evaluates the effect of increasing rotational angle on surgical performance. Surgical residents (group 1) (n = 6) and attending surgeons (group 2) (n = 4) were tested on two laparoscopic skills. The tasks consisted of passing a suture through an aperture, and laparoscopic knot tying. These tasks were assessed at 15 degrees intervals between 0 degrees and 90 degrees , on three consecutive repetitions. The participant's performance was evaluated based on the time required to complete the tasks and number of errors incurred. There was an increasing deterioration in suturing performance as the degree of image rotation was increased. Participants showed a statistically significant 20-120% progressive increase in time to completion of the tasks (p = 0.004), with error rates increasing from 10% to 30% (p = 0.04) as the angle increased from 0 degrees to 90 degrees. Knot-tying performance similarly showed a decrease in performance that was evident in the less experienced surgeons (p = 0.02) but with no obvious effect on the advanced laparoscopic surgeons. When evaluated independently and as a group, both novice and experienced laparoscopic surgeons showed significant prolongation to completion of suturing tasks with increased errors as the rotational angle increased. The knot-tying task shows that experienced surgeons may be able to overcome rotational effects to some extent. This is consistent with results from cognitive neuroscience research evaluating the processing of directional information in spatial motor tasks. It appears that these tasks utilize the time-consuming processes of mental rotation and memory scanning. Optimal performance during laparoscopic procedures requires that the rotation of the camera, and thus the image, be kept to a minimum to maintain a stable horizon. New technology that corrects the

  3. Impact of Resident Rotations on Critically Ill Patient Outcomes: Results of a French Multicenter Observational Study.

    PubMed

    Chousterman, Benjamin G; Pirracchio, Romain; Guidet, Bertrand; Aegerter, Philippe; Mentec, Hervé

    2016-01-01

    The impact of resident rotation on patient outcomes in the intensive care unit (ICU) has been poorly studied. The aim of this study was to address this question using a large ICU database. We retrospectively analyzed the French CUB-REA database. French residents rotate every six months. Two periods were compared: the first (POST) and fifth (PRE) months of the rotation. The primary endpoint was ICU mortality. The secondary endpoints were the length of ICU stay (LOS), the number of organ supports, and the duration of mechanical ventilation (DMV). The impact of resident rotation was explored using multivariate regression, classification tree and random forest models. 262,772 patients were included between 1996 and 2010 in the database. The patient characteristics were similar between the PRE (n = 44,431) and POST (n = 49,979) periods. Multivariate analysis did not reveal any impact of resident rotation on ICU mortality (OR = 1.01, 95% CI = 0.94; 1.07, p = 0.91). Based on the classification trees, the SAPS II and the number of organ failures were the strongest predictors of ICU mortality. In the less severe patients (SAPS II<24), the POST period was associated with increased mortality (OR = 1.65, 95%CI = 1.17-2.33, p = 0.004). After adjustment, no significant association was observed between the rotation period and the LOS, the number of organ supports, or the DMV. Resident rotation exerts no impact on overall ICU mortality at French teaching hospitals but might affect the prognosis of less severe ICU patients. Surveillance should be reinforced when treating those patients.

  4. Impact of Resident Rotations on Critically Ill Patient Outcomes: Results of a French Multicenter Observational Study

    PubMed Central

    Guidet, Bertrand; Aegerter, Philippe; Mentec, Hervé

    2016-01-01

    Purpose The impact of resident rotation on patient outcomes in the intensive care unit (ICU) has been poorly studied. The aim of this study was to address this question using a large ICU database. Methods We retrospectively analyzed the French CUB-REA database. French residents rotate every six months. Two periods were compared: the first (POST) and fifth (PRE) months of the rotation. The primary endpoint was ICU mortality. The secondary endpoints were the length of ICU stay (LOS), the number of organ supports, and the duration of mechanical ventilation (DMV). The impact of resident rotation was explored using multivariate regression, classification tree and random forest models. Results 262,772 patients were included between 1996 and 2010 in the database. The patient characteristics were similar between the PRE (n = 44,431) and POST (n = 49,979) periods. Multivariate analysis did not reveal any impact of resident rotation on ICU mortality (OR = 1.01, 95% CI = 0.94; 1.07, p = 0.91). Based on the classification trees, the SAPS II and the number of organ failures were the strongest predictors of ICU mortality. In the less severe patients (SAPS II<24), the POST period was associated with increased mortality (OR = 1.65, 95%CI = 1.17–2.33, p = 0.004). After adjustment, no significant association was observed between the rotation period and the LOS, the number of organ supports, or the DMV. Conclusion Resident rotation exerts no impact on overall ICU mortality at French teaching hospitals but might affect the prognosis of less severe ICU patients. Surveillance should be reinforced when treating those patients. PMID:27627449

  5. Living with a symptomatic rotator cuff tear ‘bad days, bad nights’: a qualitative study

    PubMed Central

    2014-01-01

    Background Rotator cuff tears are a common cause of shoulder pain. There is an absence of information about symptomatic rotator cuffs from the patients’ perspective; this limits the information clinicians can share with patients and the information that patients can access via sources such as the internet. This study describes the experiences of people with a symptomatic rotator cuff, their symptoms, the impact upon their daily lives and the coping strategies utilised by study participants. Methods An interpretive phenomenological analysis approach was used. 20 participants of the UKUFF trial (The United Kingdom Rotator Cuff Surgery Trial) agreed to participate in in-depth semi-structured interviews about their experiences about living with a symptomatic rotator cuff tear. Interviews were digitally recorded and fully transcribed. Field notes, memos and a reflexive diary were used. Data was coded in accordance with interpretive phenomenological analysis. Peer review, code-recode audits and constant comparison of data, codes and categories occurred throughout. Results The majority of patients described intense pain and severely disturbed sleep. Limited movement and reduced muscle strength were described by some participants. The predominantly adverse impact that a symptomatic rotator cuff tear had upon activities of daily living, leisure activities and occupation was described. The emotional and financial impact and impact upon caring roles were detailed. Coping strategies included attempting to carry on as normally as possible, accepting their condition, using their other arm, using analgesics, aids and adaptions. Conclusions Clinicians need to appreciate and understand the intensity and shocking nature of pain that may be experienced by participants with known rotator cuff tears and understand the detrimental impact tears can have upon all areas of patient’s lives. Clinicians also need to be aware of the potential emotional impact caused by cuff tears and to

  6. Contribution of posterolateral corner structures to knee joint translational and rotational stabilities: a computational study.

    PubMed

    Kim, Yoon Hyuk; Purevsuren, Tserenchimed; Kim, Kyungsoo; Oh, Kwang-Jun

    2013-09-01

    It has been reported that posterolateral corner structures, including the lateral collateral ligament, the popliteus tendon, and the popliteofibular ligament, may play important roles in reducing external rotational and posterior translational instabilities. However, there are few studies focusing on the quantitative influence of posterolateral corner structures on knee joint stability, due to the difficulty of controlling experimental conditions. In this study, a knee model that included posterolateral corner structures was developed. It was validated by comparison to previous experimental studies using the posterior drawer test, dial test, and varus stress test. The posterior translation, external rotation, and varus rotation were then predicted in order to investigate the contribution of posterolateral corner structures to translational and rotational stabilities. Our results indicate that posterolateral corner structures, including the popliteofibular ligament and the popliteus tendon, could contribute to posterior translational and external rotational stabilities, as clinical observations had suggested. Therefore, the addition of posterolateral corner structures to knee joint models may improve the utility of such models.

  7. Differentially rotating relativistic magnetic jets. Asymptotic trans-field force-balance including differential rotation.

    NASA Astrophysics Data System (ADS)

    Fendt, C.

    1997-07-01

    Highly collimated jets are observed in various astronomical objects, as active galactic nuclei, galactic high energy sources, and also young stellar objects. There is observational indication that these jets originate in accretion disks, and that magnetic fields play an important role for the jet collimation and plasma acceleration. The rapid disk rotation close to the central object leads to relativistic rotational velocities of the magnetic field lines. The structure of these axisymmetric magnetic flux surfaces follows from the trans-field force-balance described by the Grad-Schlueter-Shafranov equation. In this paper, we investigate the asymptotic field structure of differentially rotating magnetic jets, widening the study by Appl & Camenzind (1993A&A...270...71A, 1993A&A...274..699A). In general, our results show that, with the same current distribution, differentially rotating jets are collimated to smaller jet radii as compared with jets with rigidly rotating field. Differentially rotating jets need a stronger net poloidal current in order to collimate to the same asymptotic radius. Current-free solutions are not possible for differentially rotating disk-jet magnetospheres with cylindrical asymptotics. We present a simple analytical relation between the poloidal current distribution and magnetic field rotation law. A general relation is derived for the current strength for jets with maximum differential rotation and minimum differential rotation. Analytical solutions are also given in the case of a field rotation leading to a degeneration of the light cylinder. By linking the asymptotic solution to a Keplerian accretion disk, 'total expansion rates' for the jets, and also the flux distribution at the foot points of the flux surfaces are derived. Large poloidal currents imply a strong opening of flux surfaces, a stronger gradient of field rotation leads to smaller expansion rates. There is indication that AGN jet expansion rates are less than in the case of

  8. Light scattering study of Salol: Exploring the effect of rotation-translation coupling

    NASA Astrophysics Data System (ADS)

    Zhang, Hepeng

    Extensive light scattering experiments, including Brillouin, Raman and photon correlation spectroscopies, have been done to study the rotational and translational dynamics and their coupling in a glassforming liquid of anisotropic molecules, Salol. Pick-Franosch theory was used to fit the full set of data. VH backscattering spectra were first fit with a hybrid function. This part of the analysis, together with photon correlation data, fixed all the parameters characterizing the pure rotational dynamics. The obtained rotational relaxation times agree with the results of dielectric and other experiments in the literature. In VH 90° fitting, the Pick-Franosch theory can produce excellent fits to all 23 spectra from 380 K to 210 K. At temperatures from 380 K to 310 K, the static shear viscosity values obtained from the fits agree with published theological results. From 280 K to 210 K, the relaxation time for shear viscosity was found to be proportional to, and 15 times smaller than, the rotational relaxation time. The stretching coefficient beta for shear viscosity is smaller than that for rotational relaxation and the strength of rotation-translation coupling increases with decreasing temperature. The difference spectra between VV 90° and VH backscattering spectra were analyzed last with the help of parameters obtained from both VH backscattering and VH90° fittings. The difference spectrum shows negative region-VV dip-at high temperatures and low frequencies. The difference spectra were first analyzed by a density-fluctuation-only model, which neglects the rotation-translation coupling. It can fit difference spectra well except where VV dip is. However, the Pick-Franosch theory, which includes rotation-translation coupling, can fit all the difference spectra including the VV dips. Thus we conclude that the VV dip is a consequence of rotation-translation coupling and related to---but less apparent than---the Rytov dip in the VH 90° spectra. The bulk viscosity was

  9. Studies of Neutron-Deficient Nuclei Near the Z = 82 Shell Closure via Cold Fusion Reactions

    NASA Astrophysics Data System (ADS)

    Carpenter, M. P.; Kondev, F. G.; Janssens, R. V. F.; Seweryniak, D.; Khoo, T. L.; Lauritsen, T.; Lister, C. J.; Zhu, S.; Camera, F.; Bracco, A.; Million, B.; Leoni, S.; Jenkins, D. G.; Wadsworth, R.

    2009-03-01

    Over the last decade, we have performed in-beam experiments using Gammasphere+FMA to measure excited states in proton-rich Au, Hg, Tl and Pb isotopes. In these studies, the use of the FMA is essential in order to differentiate evaporation residues from the large fission background which dominates the reaction cross-section. In addition, we have found that using near-symmetric reactions at bombarding energies near the Coloumb barrier is beneficial in performing these studies. By keeping the bombarding energy low, fission is minimized and the reaction products are concentrated in only a few channels. New results have recently been obtained using the 90Zr+92Mo reaction to study shape co-existence in 181Tl via the lp evaporation channel. In addition, we have measured the total γ-ray energy and multiplicity associated with the surviving compund system, 179Au, following the fusion reaction, 90Zr+89Y.

  10. 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.

  11. Hyperfine Interactions of 57Fe Nuclei in the Study of Interdiffusion Phenomena and Phase Formation

    NASA Astrophysics Data System (ADS)

    Carbucicchio, M.; Palombarini, G.; Rateo, M.

    1998-07-01

    The effects of interdiffusion phenomena and reactions occurring in the early stages of the interaction at 1273 K between iron and chromium monoborides were studied by transmission Mössbauer and X-ray diffraction techniques, and modifications occurring in Fe/Al multilayers during both deposition and subsequent thermal aging at 400 K in vacuum or air were studied by conversion electron Mössbauer and Auger electron depth profiling techniques. In both cases the main objective of the work was to obtain a better understanding of the mechanisms of modification of the materials under examination with a view towards improving the properties of materials and coatings for specific applications.

  12. Systematic study of the fragmentation of low-lying dipole strength in odd-A rare earth nuclei investigated in nuclear resonance fluorescence experiments

    NASA Astrophysics Data System (ADS)

    Nord, A.; Schiller, A.; Eckert, T.; Beck, O.; Besserer, J.; von Brentano, P.; Fischer, R.; Herzberg, R.-D.; Jäger, D.; Kneissl, U.; Margraf, J.; Maser, H.; Pietralla, N.; Pitz, H. H.; Rittner, M.; Zilges, A.

    1996-11-01

    Nuclear resonance fluorescence experiments were performed on the rare earth nuclei 155Gd and 159Tb to study the fragmentation of the M1 scissors mode in odd deformed nuclei and to establish a kind of systematics. Using the bremsstrahlung photon beam of the Stuttgart Dynamitron (end point energy 4.1 MeV) and high resolution Ge-γ spectrometers detailed information was obtained on excitation energies, decay widths, transition probabilities, and branching ratios. The results are compared to those observed recently for the neighboring odd nuclei 161,163Dy and 157Gd. Whereas in the odd Dy isotopes the dipole strength is rather concentrated, both Gd isotopes show a strong fragmentation of the strength into about 25 (155Gd) and 90 transitions (157Gd) in the energy range 2-4 MeV. The nucleus 159Tb linking the odd Dy and Gd isotopes exhibits an intermediate strength fragmentation. In general the observed total strength in the odd nuclei is reduced by a factor of 2-3 as compared to their neighboring even-even isotopes. The different fragmentation behavior of the dipole strengths in the odd Dy and Gd isotopes is unexplained up to now.

  13. Studies of heavy-ion reactions and transuranic nuclei. Progress report, September 1, 1992--August 31, 1993

    SciTech Connect

    Schroeder, W.U.

    1993-08-01

    This report contain papers on the following topics: The Cold-Fusion Saga; Decay Patterns of Dysprosium Nuclei Produced in {sup 32}S + {sup 118,124}Sn Fusion Reactions; Unexpected Features of Reactions Between Very Heavy Ions at Intermediate Bombarding Energies; Correlations Between Neutrons and Charged Products from the Dissipative Reaction {sup 197}Au+{sup 208}Pb at E/A = 29 MeV; Dissipative Dynamics of Projectile-Like Fragment Production in the Reaction {sup 209}Bi+{sup 136}Xe at E/A = 28.2 MeV; Dynamical Production of Intermediate-Mass Fragments in Peripheral {sup 209}Bi+{sup 136}Xe Collisions at E{sub lab}/A = 28.2 MeV; The Rochester 960-Liter Neutron Multiplicity Meter; A Simple Pulse Processing Concept for a Low-Cost Pulse-Shape-Based Particle Identification; A One-Transistor Preamplifier for PMT Anode Signals; A Five-Channel Multistop TDC/Event Handler for the SuperBall Neutron Multiplicity Meter; Construction of the SuperBall -- a 16,000-Liter Neutron Detector for Calorimetric Studies of Intermediate-Energy Heavy-Ion Reactions; A Computer Code for Light Detection Efficiency Calculations for Photo-multipliers of a Neutron Detector; Evaluation of Gd-Loaded Liquid Scintillators for the SuperBall Neutron Calorimeter; and Measurement of the Interaction of Cosmic-Ray {mu}{sup {minus}} with a Muon Telescope.

  14. An observational study of atmospheric ice nuclei number concentration during three fog-haze weather periods in Shenyang, northeastern China

    NASA Astrophysics Data System (ADS)

    Li, Liguang; Zhou, Deping; Wang, Yangfeng; Hong, Ye; Cui, Jin; Jiang, Peng

    2017-05-01

    Characteristics of ice nuclei (IN) number concentrations during three fog-haze weather periods from November 2010 to January 2012 in Shenyang were presented in this paper. A static diffusion chamber was used and sampling of IN aerosols was conducted using a membrane filter method. Sampling membrane filter processing conditions were unified in the activation temperature at - 15 °C under conditions of 20% ice supersaturation and 3% water supersaturation. The variations of natural IN number concentrations in different weather conditions were investigated. The relations between the meteorological factors and the IN number concentrations were analyzed, and relationships between pollutants and IN number concentrations were also studied. The results showed that mean IN number concentration were 38.68 L- 1 at - 20 °C in Shenyang, for all measurements. Mean IN number concentrations are higher during haze days (55.92 L- 1 at - 20 °C) and lower after rain. Of all meteorological factors, wind speed, boundary stability, and airflow direction appeared to influence IN number concentrations. IN number concentrations were positively correlated with particulate matters PM1, PM2.5, and PM10 during haze weather.

  15. Experimental Studies of Quark-Gluon Structure of Nucleons and Nuclei

    SciTech Connect

    Kyle, Gary

    2004-12-17

    The NMSU group has a lengthy history in the study of the nucleon structure and in particular its spin structure in terms of its fundamental constituents. This line of research is continuing in our current involvement in experiments at Brookhaven National Lab and the Thomas Jefferson National Accelerator Facility.

  16. D mesic nuclei

    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.

  17. The role of dorsal premotor cortex in mental rotation: A transcranial magnetic stimulation study.

    PubMed

    Cona, Giorgia; Panozzo, Giulia; Semenza, Carlo

    2017-08-01

    Although activation of dorsal premotor cortex (PMd) has been consistently observed in the neuroimaging studies of mental rotation, the functional meaning of PMd activation is still unclear and multiple alternative explanations have been suggested. The present study used repetitive transcranial magnetic stimulation (rTMS) to investigate the role of PMd in mental rotation. Two tasks were used, involving mental rotation of hands and abstract objects, with either matching (same stimuli) or mirror stimuli. Compared to sham stimulation, TMS over right and left PMd regions significantly affected accuracy in the object task, specifically for the same stimuli. Furthermore, response times were longer following right PMd stimulation in both the object and the hand tasks, but again, selectively for the same stimuli. The effect of rotational angle on response times and accuracies was greater for the same stimuli. Moreover TMS over PMd impaired the performance accuracy selectively in these stimuli, mainly in a task that included abstract objects. For these reasons, the present findings indicate a contribution of PMd to mental rotation. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Association of Strength Measurement with Rotator Cuff Tear in Patients with Shoulder Pain: The ROW Study

    PubMed Central

    Miller, Jennifer Earle; Higgins, Laurence D.; Dong, Yan; Collins, Jamie E.; Bean, Jonathan F.; Seitz, Amee L.; Katz, Jeffrey N.; Jain, Nitin B.

    2016-01-01

    Objective This study examines the association between strength measurements and supraspinatus tear in patients with shoulder pain. This study characterized determinants of abduction strength among patients with tears. Design Two-hundred and eight patients with shoulder pain (69 with and 110 without tear) were recruited. Strength was tested using hand-held dynamometer. Supraspinatus tears were diagnosed by combination of clinical assessment and blinded MRI review. Associations of supraspinatus tear with patient characteristics and strength measurements (abduction, internal rotation and external rotation) were assessed using multivariable logistic regression models. Results Patients with supraspinatus tear had decreased abduction strength (p=0.02) and decreased external rotation strength (p<0.01). When adjusted for age, sex, tear laterality, and BMI, decreased abduction strength (OR= 1.18 per kg, 95% C.I.=1.06–1.32) and decreased external rotation strength (OR=1.29 per kg, 95% C.I.=1.14–1.48) were associated with supraspinatus tear. In patients with tear, age ≥60 years, female sex, and VAS pain score were significantly associated with decreased abduction strength but tear size, fatty infiltration, and atrophy were not. Conclusions Decreased abduction and external rotation strength were associated with supraspinatus tear in patients with shoulder pain. In this cohort, the abduction strength of patients with tears, was influenced by demographic factors but not tear characteristics. PMID:26098921

  19. An experimental study of counter-rotating cores in elliptical galaxies

    NASA Technical Reports Server (NTRS)

    Miller, R. H.; Roelofs, G. R.; Smith, B. F.

    1990-01-01

    Recent observational studies (Franx and Illingworth 1987; Jedrzejewski and Schechter 1988; Bender 1988; Illingworth and Franx 1989) have shown that some elliptical galaxies have a small region near the center that rotates in the opposite direction from the outer parts of the galaxy. Often the rotation in the central part is much faster than that in the outer part. A few other galaxies show a small region near the center that rotates in the same direction as the rest of the galaxy, but much faster. Either way, the part near the center that shows a strange pattern of rotation (the 'core') has been interpreted as a distinct dynamical subsystem. Very briefly, the observational data seem to be that anomalies show up in rotation curves near the centers of some elliptical galaxies and that galaxies with these strange rotational properties do not show a photometric signature: there are no noticeable bumps in the brightness profile and no unusual shapes of isophotal contours that would suggest an excess of matter concentrated near the center. No strong color variations have been reported. The puzzle is to learn what we can about elliptical galaxies in general, and about galaxies with strange central regions in particular, from these observational facts. The authors' approach is experimental. They make a guess about the form of the dynamically distinct subsystem, and then build a galaxy model to test experimental consequences such as the amount of matter required to produce observable effects and the length of time over which these effects would remain observable. They sidestep questions about how the galaxy might have gotten to be that way in the first place. That gives them more freedom to explore a variety of suggestions about what kind of dynamical system might give rise to the observed rotational patterns.

  20. Rotator cuff-sparing approaches for glenohumeral joint access: an anatomic feasibility study.

    PubMed

    Amirthanayagam, Tressa D; Amis, Andrew A; Reilly, Peter; Emery, Roger J H

    2017-03-01

    The deltopectoral approach for total shoulder arthroplasty can result in subscapularis dysfunction. In addition, glenoid wear is more prevalent posteriorly, a region difficult to access with this approach. We propose a posterior approach for access in total shoulder arthroplasty that uses the internervous interval between the infraspinatus and teres minor. This study compares this internervous posterior approach with other rotator cuff-sparing techniques, namely, the subscapularis-splitting and rotator interval approaches. The 3 approaches were performed on 12 fresh frozen cadavers. The degree of circumferential access to the glenohumeral joint, the force exerted on the rotator cuff, the proximity of neurovascular structures, and the depth of the incisions were measured, and digital photographs of the approaches in different arm positions were analyzed. The posterior approach permits direct linear access to 60% of the humeral and 59% of the glenoid joint circumference compared with 39% and 42% for the subscapularis-splitting approach and 37% and 28% for the rotator interval approach. The mean force of retraction on the rotator cuff was 2.76 (standard deviation [SD], 1.10) N with the posterior approach, 2.72 (SD, 1.22) N with the rotator interval, and 4.75 (SD, 2.56) N with the subscapularis-splitting approach. From the digital photographs and depth measurements, the estimated volumetric access available for instrumentation during surgery was comparable for the 3 approaches. The internervous posterior approach provides greater access to the shoulder joint while minimizing damage to the rotator cuff. Copyright © 2017. Published by Elsevier Inc.

  1. Large-scale shell model calculations for odd-odd nuclei and comparison to experimental studies of fission product nuclei in the /sup 132/Sn region

    SciTech Connect

    Lane, S.M.; Henry, E.A.; Meyer, R.A.

    1985-01-08

    Experimental spectroscopy data of fission products have been obtained using highly automated and rapid chemical separations followed by automated spectroscopy studies of isolated fission products. These data have established the presence of only a single level with spin-parity of 1/sup +/ below 1500 keV of excitation in Z = 51 /sup 132/Sb/sub 81/. This is in contrast to the results of our studies of /sup 130/Sb and /sup 134/I. For /sup 134/I, the N = 81 isotone with Z = 53, we can characterize three 1/sup +/ levels below 1200 keV. For /sup 130/Sb/sub 79/ that has a neutron pair less than /sup 132/Sb, we can identify two 1/sup +/ levels below 1100 keV. We can account for the additional levels using the LLNL shell-model code which is based on the Lanczos tridiagonalization algorithm using an uncoupled m-scheme basis and vector manipulations. The 1g/sub 7/2/, 2d/sub 5/2/, 2d/sub 3/2/, 1h/sub 11/2/, and 3s/sub 1/2/ orbitals are available to the valence protons and the 2d/sub 5/2/, 2d/sub 3/2/, 1h/sub 11/2/, and 3s/sub 1/2/ orbitals are available to the valence neutron holes. Analysis of the wavefunctions show the dominant role of three nucleon cluster configurations in producing the increased number of states at low energy. The absence of nucleon cluster configurations in the parent nucleus /sup 130/Sn is used to explain the reduction of approximately a factor of 20 in the Gamow-Teller beta strength to the low lying 1/sup +/ levels of /sup 130/Sb. 27 references.

  2. Studies of Neutron-Deficient Nuclei Near the Z = 82 Shell Closure via Cold Fusion Reactions

    SciTech Connect

    Carpenter, M. P.; Kondev, F. G.; Janssens, R. V. F.; Seweryniak, D.; Khoo, T. L.; Lauritsen, T.; Lister, C. J.; Zhu, S.; Camera, F.; Bracco, A.; Million, B.; Leoni, S.; Jenkins, D. G.; Wadsworth, R.

    2009-03-04

    Over the last decade, we have performed in-beam experiments using Gammasphere+FMA to measure excited states in proton-rich Au, Hg, Tl and Pb isotopes. In these studies, the use of the FMA is essential in order to differentiate evaporation residues from the large fission background which dominates the reaction cross-section. In addition, we have found that using near-symmetric reactions at bombarding energies near the Coloumb barrier is beneficial in performing these studies. By keeping the bombarding energy low, fission is minimized and the reaction products are concentrated in only a few channels. New results have recently been obtained using the {sup 90}Zr+{sup 92}Mo reaction to study shape co-existence in {sup 181}Tl via the lp evaporation channel. In addition, we have measured the total {gamma}-ray energy and multiplicity associated with the surviving compound system, {sup 179}Au, following the fusion reaction, {sup 90}Zr+{sup 89}Y.

  3. Association Between Cardiovascular Disease Risk Factors and Rotator Cuff Tendinopathy: A Cross-Sectional Study.

    PubMed

    Applegate, Kara Arnold; Thiese, Matthew S; Merryweather, Andrew S; Kapellusch, Jay; Drury, David L; Wood, Eric; Kendall, Richard; Foster, James; Garg, Arun; Hegmann, Kurt T

    2017-02-01

    Recent evidence has found potential associations between cardiovascular disease (CVD) risk factors and common musculoskeletal disorders. We evaluated possible associations between risk factors and both glenohumeral joint pain and rotator cuff tendinopathy. Data from WISTAH hand study participants (n = 1226) were assessed for associations between Framingham Heart Study CVD risk factors and both health outcomes. A strong association was observed between CVD risk scores and both glenohumeral joint pain and rotator cuff tendinopathy. Peak odds ratios (ORs) of the adjusted models were 4.55 [95% confidence interval (95% CI) 1.97 to 10.31] and 5.97 (95% CI 2.12 to 16.83), respectively. The results show a dose-response trend of increasing risk. Individual risk factors were associated with both outcomes. Combined, CVD risk factors demonstrated a strong correlation with glenohumeral joint pain and an even stronger correlation with rotator cuff tendinopathy. Results suggest a potentially modifiable disease mechanism.

  4. Experimental study of bubble cavities attached to a rotating shaft in a reservoir

    NASA Technical Reports Server (NTRS)

    Hendricks, R. C.; Braun, M. J.; Mullen, R. L.

    1984-01-01

    Bubble cavities formed by air entrainment and attached to a rotating shaft in an oil reservoir were studied. The cavities appear to the unaided eye as toroidal. High speed photography, however, reveals the individuality of the bubble cavities and their near solid body rotational characteristics. The cavities are distorted by the rotation effects but remain attached and tend to merge because of edge effects in the axial direction. The flow field within the reservoir is influenced by the unusual character of the two phase fluid found there; the vorticity is readily visualized. Other examples of vapor entrapment at the inlet of an eccentric rotor are also discussed. A simplified analytical method is provided, and a numerical analysis is being investigated. Vapor (void) entrainment and generation can significantly alter leakage rates and stability of seals, bearings, and dampers. Recognition of these effects in the component design systems will result only after detailed studies of the above phenomena.

  5. Photophysical and theoretical studies of diphenylacetylene derivatives with restricted rotation

    NASA Astrophysics Data System (ADS)

    Szyszkowska, Małgorzata; Czaplewski, Cezary; Wiczk, Wiesław

    2017-06-01

    Diphenylacetylene derivatives containing electron-donor (amino) and electron-acceptor (ester) groups in 2,2‧ or 3,2‧ positions in phenyl rings were synthesized to study the effects of intramolecular charge transfer and stiffening of the conformation by intramolecular hydrogen bond on the photophysical properties. Additionally, the derivatives with and without a steric hindrance were studied to determine the effect of conformational freedom on photophysical properties. The persistence of the intramolecular hydrogen bond and the corresponding twisted conformations as well as the conformational flexibility were also established by DFT calculations.

  6. Heating of Nuclei with Energetic Antiprotons

    SciTech Connect

    Goldenbaum, F.; Bohne, W.; Eades, J.; Egidy, T.v.; Figuera, P.; Fuchs, H.; Galin, J.; Golubeva, Y.S.; Gulda, K.; Hilscher, D.; Iljinov, A.S.; Jahnke, U.; Jastrzebski, J.; Kurcewicz, W.; Lott, B.; Morjean, M.; Pausch, G.; Peghaire, A.; Pienkowski, L.; Polster, D.; Proschitzki, S.; Quednau, B.; Rossner, H.; Schmid, S.; Schmid, W.; Ziem, P. |||||||

    1996-08-01

    The annihilation of energetic (1.2 GeV) antiprotons is exploited to deposit maximum thermal excitation (up to 1000 MeV) in massive nuclei (Cu, Ho, Au, and U) while minimizing the contribution from collective excitation such as rotation, shape distortion, and compression. Excitation energy distributions {ital d}{sigma}/{ital dE}{asterisk} are deduced from eventwise observation of the whole nuclear evaporation chain with two 4{pi} detectors for neutrons and charged particles. The nuclei produced in this way are found to decay predominantly statistically, i.e., by evaporation. {copyright} {ital 1996 The American Physical Society.}

  7. An Event-Related Potentials Study of Mental Rotation in Identifying Chemical Structural Formulas

    ERIC Educational Resources Information Center

    Huang, Chin-Fei; Liu, Chia-Ju

    2012-01-01

    The purpose of this study was to investigate how mental rotation strategies affect the identification of chemical structural formulas. This study conducted event-related potentials (ERPs) experiments. In addition to the data collected in the ERPs, a Chemical Structure Conceptual Questionnaire and interviews were also admin-istered for data…

  8. Rotational Mobility in a Crystal Studied by Dielectric Relaxation Spectroscopy

    ERIC Educational Resources Information Center

    Dionisio, Madalena S. C.; Diogo, Herminio P.; Farinha, J. P. S.; Ramos, Joaquim J. Moura

    2005-01-01

    A laboratory experiment for undergraduate physical chemistry courses that uses the experimental technique of dielectric relaxation spectroscopy to study molecular mobility in a crystal is proposed. An experiment provides an excellent opportunity for dealing with a wide diversity of important basic concepts in physical chemistry.

  9. Electrical spectra of undisturbed soil from a crop rotation study

    USDA-ARS?s Scientific Manuscript database

    Soil permittivity can be determined across a range of frequencies, but little is known about how the factors derived from the frequency spectra are related to soil pore structure or crop management. The purpose of this study was to test the use of a 12-wire, quasi-coaxial probe for determining soil ...

  10. Rotation lightcurves of small jovian Trojan asteroids

    NASA Astrophysics Data System (ADS)

    French, Linda M.; Stephens, Robert D.; Coley, Daniel; Wasserman, Lawrence H.; Sieben, Jennifer

    2015-07-01

    Several lines of evidence support a common origin for, and possible hereditary link between, cometary nuclei and jovian Trojan asteroids. Due to their distance and low albedos, few comet-sized Trojans have been studied. We present new lightcurve information for 19 Trojans ≲ 30 km in diameter, more than doubling the number of objects in this size range for which some rotation information is known. The minimum densities for objects with complete lightcurves are estimated and are found to be comparable to those measured for cometary nuclei. A significant fraction (∼40%) of this observed small Trojan population rotates slowly (P > 24 h), with measured periods as long as 375 h (Warner, B.D., Stephens, R.D. [2011]. Minor Planet Bull. 38, 110-111). The excess of slow rotators may be due to the YORP effect. Results of the Kolmogorov-Smirnov test suggest that the distribution of Trojan rotation rates is dissimilar to those of Main Belt Asteroids of the same size. Concerted observations of a large number of Trojans could establish the spin barrier (Warner, B.D., Harris, A.W., Pravec, P. [2009]. Icarus 202, 134-146), making it possible to estimate densities for objects near the critical period.

  11. Target dependence in the study of collective modes in stable and exotic Ni nuclei

    NASA Astrophysics Data System (ADS)

    Le Bleis, T.; Rossi, D.; Klimkiewicz, A.; Adrich, P.; Boretzky, K.; Aksouh, F.; Alvarez-Pol, H.; Aumann, T.; Benlliure, J.; Boehmer, M.; Casarejos, E.; Chartier, M.; Chatillon, A.; Cortina-Gil, D.; Datta Pramanik, U.; Emling, H.; Ershova, O.; Fernandez-Dominguez, B.; Geissel, H.; Gorska, M.; Heil, M.; Johansson, H.; Junghans, A. R.; Kiselev, O.; Kratz, J. V.; Kurz, N.; Labiche, M.; Lemmon, R.; Litvinov, Y.; Mahata, K.; Maierbeck, P.; Nilsson, T.; Nociforo, C.; Palit, R.; Paschalis, S.; Plag, R.; Reifarth, R.; Simon, H.; Sümmerer, K.; Wagner, A.; Walus, W.; Weick, H.; Winkler, M.

    2010-01-01

    The appearance of the pygmy-dipole-resonance is a recently observed phenomenon that can be related to neutron-matter properties. Its study can be a tool to determine the nuclear symmetry-energy parameters and thus can contribute constraining neutron star models. We present the (γ,n) cross sections for different Ni isotopes obtained from a measurement in inverse kinematics at about 500 MeV/u in the LAND reaction setup at GSI. The question of the disentanglement of the Coulomb and nuclear contributions is addressed.

  12. Role of feedback in AGN-host coevolution: A study from partially obscured active galactic nuclei

    NASA Astrophysics Data System (ADS)

    Wang, J.

    2015-05-01

    Partially obscured AGNs within a redshift range z = 0.011 ∼ 0.256 are used to re-study the role of feedback in the AGN-host coevolution issue in terms of their [OIII] λ 5007 emission line profile. The spectra of these objects enable us to determine the AGN's accretion properties directly from their broad H α emission. This is essential for getting rid of the "circular reasoning" in our previous study of narrow emission-line galaxies, in which the [OIII] emission line was used not only as a proxy of AGN's bolometric luminosity, but also as a diagnostic of outflow. In addition, the measurement of Dn (4000) index is improved by removing an underlying AGN's continuum according to the corresponding broad H α emission. With these improvements, we confirm and reinforce the correlation between L /LEdd and stellar population age. More important is that this correlation is found to be related to both [OIII] line blue asymmetry and bulk blueshift velocity, which suggests a linkage between SMBH growth and host star formation through the feedback process. The current sample of partially obscured AGNs shows that the composite galaxies have younger host stellar population, higher Eddington ratio, less significant [OIII] blue wing and smaller bulk [OIII] line shift than do the Seyfert galaxies.

  13. Vestibular convergence patterns in vestibular nuclei neurons of alert primates.

    PubMed

    Dickman, J David; Angelaki, Dora E

    2002-12-01

    Sensory signal convergence is a fundamental and important aspect of brain function. Such convergence may often involve complex multidimensional interactions as those proposed for the processing of otolith and semicircular canal (SCC) information for the detection of translational head movements and the effective discrimination from physically congruent gravity signals. In the present study, we have examined the responses of primate rostral vestibular nuclei (VN) neurons that do not exhibit any eye movement-related activity using 0.5-Hz translational and three-dimensional (3D) rotational motion. Three distinct neural populations were identified. Approximately one-fourth of the cells exclusively encoded rotational movements (canal-only neurons) and were unresponsive to translation. The canal-only central neurons encoded head rotation in SCC coordinates, exhibited little orthogonal canal convergence, and were characterized with significantly higher sensitivities to rotation as compared to primary SCC afferents. Another fourth of the neurons modulated their firing rates during translation (otolith-only cells). During rotations, these neurons only responded when the axis of rotation was earth-horizontal and the head was changing orientation relative to gravity. The remaining one-half of VN neurons were sensitive to both rotations and translations (otolith + canal neurons). Unlike primary otolith afferents, however, central neurons often exhibited significant spatiotemporal (noncosine) tuning properties and a wide variety of response dynamics to translation. To characterize the pattern of SCC inputs to otolith + canal neurons, their rotational maximum sensitivity vectors were computed using exclusively responses during earth-vertical axis rotations (EVA). Maximum sensitivity vectors were distributed throughout the 3D space, suggesting strong convergence from multiple SCCs. These neurons were also tested with earth-horizontal axis rotations (EHA), which would activate

  14. Vestibular convergence patterns in vestibular nuclei neurons of alert primates

    NASA Technical Reports Server (NTRS)

    Dickman, J. David; Angelaki, Dora E.

    2002-01-01

    Sensory signal convergence is a fundamental and important aspect of brain function. Such convergence may often involve complex multidimensional interactions as those proposed for the processing of otolith and semicircular canal (SCC) information for the detection of translational head movements and the effective discrimination from physically congruent gravity signals. In the present study, we have examined the responses of primate rostral vestibular nuclei (VN) neurons that do not exhibit any eye movement-related activity using 0.5-Hz translational and three-dimensional (3D) rotational motion. Three distinct neural populations were identified. Approximately one-fourth of the cells exclusively encoded rotational movements (canal-only neurons) and were unresponsive to translation. The canal-only central neurons encoded head rotation in SCC coordinates, exhibited little orthogonal canal convergence, and were characterized with significantly higher sensitivities to rotation as compared to primary SCC afferents. Another fourth of the neurons modulated their firing rates during translation (otolith-only cells). During rotations, these neurons only responded when the axis of rotation was earth-horizontal and the head was changing orientation relative to gravity. The remaining one-half of VN neurons were sensitive to both rotations and translations (otolith + canal neurons). Unlike primary otolith afferents, however, central neurons often exhibited significant spatiotemporal (noncosine) tuning properties and a wide variety of response dynamics to translation. To characterize the pattern of SCC inputs to otolith + canal neurons, their rotational maximum sensitivity vectors were computed using exclusively responses during earth-vertical axis rotations (EVA). Maximum sensitivity vectors were distributed throughout the 3D space, suggesting strong convergence from multiple SCCs. These neurons were also tested with earth-horizontal axis rotations (EHA), which would activate

  15. Vestibular convergence patterns in vestibular nuclei neurons of alert primates

    NASA Technical Reports Server (NTRS)

    Dickman, J. David; Angelaki, Dora E.

    2002-01-01

    Sensory signal convergence is a fundamental and important aspect of brain function. Such convergence may often involve complex multidimensional interactions as those proposed for the processing of otolith and semicircular canal (SCC) information for the detection of translational head movements and the effective discrimination from physically congruent gravity signals. In the present study, we have examined the responses of primate rostral vestibular nuclei (VN) neurons that do not exhibit any eye movement-related activity using 0.5-Hz translational and three-dimensional (3D) rotational motion. Three distinct neural populations were identified. Approximately one-fourth of the cells exclusively encoded rotational movements (canal-only neurons) and were unresponsive to translation. The canal-only central neurons encoded head rotation in SCC coordinates, exhibited little orthogonal canal convergence, and were characterized with significantly higher sensitivities to rotation as compared to primary SCC afferents. Another fourth of the neurons modulated their firing rates during translation (otolith-only cells). During rotations, these neurons only responded when the axis of rotation was earth-horizontal and the head was changing orientation relative to gravity. The remaining one-half of VN neurons were sensitive to both rotations and translations (otolith + canal neurons). Unlike primary otolith afferents, however, central neurons often exhibited significant spatiotemporal (noncosine) tuning properties and a wide variety of response dynamics to translation. To characterize the pattern of SCC inputs to otolith + canal neurons, their rotational maximum sensitivity vectors were computed using exclusively responses during earth-vertical axis rotations (EVA). Maximum sensitivity vectors were distributed throughout the 3D space, suggesting strong convergence from multiple SCCs. These neurons were also tested with earth-horizontal axis rotations (EHA), which would activate

  16. Experimental study on active structural acoustic control of rotating machinery using rotating piezo-based inertial actuators

    NASA Astrophysics Data System (ADS)

    Zhao, G.; Alujević, N.; Depraetere, B.; Pinte, G.; Swevers, J.; Sas, P.

    2015-07-01

    In this paper, two Piezo-Based Rotating Inertial Actuators (PBRIAs) are considered for the suppression of the structure-borne noise radiated from rotating machinery. As add-on devices, they can be directly mounted on a rotational shaft, in order to intervene as early as possible in the transfer path between disturbance and the noise radiating surfaces. A MIMO (Multi-Input-Multi-Output) form of the FxLMS control algorithm is employed to generate the appropriate actuation signals, relying on a linear interpolation scheme to approximate time varying secondary plants. The proposed active vibration control approach is tested on an experimental test bed comprising a rotating shaft mounted in a frame to which a noise-radiating plate is attached. The disturbance force is introduced by an electro-dynamic shaker. The experimental results show that when the shaft spins below 180 rpm, more than a 7 dB reduction can be achieved in terms of plate vibrations, along with a reduction in the same order of magnitude in terms of noise radiation.

  17. β-Decay Studies of r-Process Nuclei Using the Advanced Implantation Detector Array (AIDA)

    NASA Astrophysics Data System (ADS)

    Griffin, C. J.; Davinson, T.; Estrade, A.; Braga, D.; Burrows, I.; Coleman-Smith, P. J.; Grahn, T.; Grant, A.; Harkness-Brennan, L. J.; Kiss, G.; Kogimtzis, M.; Lazarus, I. H.; Letts, S. C.; Liu, Z.; Lorusso, G.; Matsui, K.; Nishimura, S.; Page, R. D.; Prydderch, M.; Phong, V. H.; Pucknell, V. F. E.; Rinta-Antila, S.; Roberts, O. J.; Seddon, D. A.; Simpson, J.; Thomas, S. L.; Woods, P. J.

    Thought to produce around half of all isotopes heavier than iron, the r-process is a key mechanism for nucleosynthesis. However, a complete description of the r-process is still lacking and many unknowns remain. Experimental determination of β-decay half-lives and β-delayed neutron emission probabilities along the r-process path would help to facilitate a greater understanding of this process. The Advanced Implantation Detector Array (AIDA) represents the latest generation of silicon implantation detectors for β-decay studies with fast radioactive ion beams. Preliminary results from commissioning experiments demonstrate successful operation of AIDA and analysis of the data obtained during the first official AIDA experiments is now under-way.

  18. A high-resolution study of the isotopes of solar flare nuclei

    NASA Technical Reports Server (NTRS)

    Mewaldt, R. A.; Spalding, J. D.; Stone, E. C.

    1984-01-01

    Individual isotopes of the elements He, C, N, O, Ne, and Mg with energies from 5 to 50 MeV per nucleon have been resolved in energetic flare particles during the September 23, 1978 solar flare event. In addition, an earlier determination of Ne-22/Ne-20 in this flare was improved on by extending the energy interval for isotope analysis. A significant difference between the isotopic composition of solar flare and solar wind neon is found, which is compared to similar evidence from studies of solar energetic particles implanted in lunar and meteoritic samples. Although limited by statistics, the measurements of He, C, N, O, and Mg isotopes are consistent with typical isotopic abundances found in other samples of solar system material. The ensemble of these results is used to test for the possibility of mass-dependent fractionation during solar flare acceleration and propagation.

  19. Study on ( n,t) Reactions of Zr, Nb and Ta Nuclei

    NASA Astrophysics Data System (ADS)

    Tel, E.; Yiğit, M.; Tanır, G.

    2012-04-01

    The world faces serious energy shortages in the near future. To meet the world energy demand, the nuclear fusion with safety, environmentally acceptability and economic is the best suited. Fusion is attractive as an energy source because of the virtually inexhaustible supply of fuel, the promise of minimal adverse environmental impact, and its inherent safety. Fusion will not produce CO2 or SO2 and thus will not contribute to global warming or acid rain. Furthermore, there are not radioactive nuclear waste problems in the fusion reactors. Although there have been significant research and development studies on the inertial and magnetic fusion reactor technology, there is still a long way to go to penetrate commercial fusion reactors to the energy market. Because, tritium self-sufficiency must be maintained for a commercial power plant. For self-sustaining (D-T) fusion driver tritium breeding ratio should be greater than 1.05. And also, the success of fusion power system is dependent on performance of the first wall, blanket or divertor systems. So, the performance of structural materials for fusion power systems, understanding nuclear properties systematic and working out of ( n,t) reaction cross sections are very important. Zirconium (Zr), Niobium (Nb) and Tantal (Ta) containing alloys are important structural materials for fusion reactors, accelerator-driven systems, and many other fields. In this study, ( n,t) reactions for some structural fusion materials such as 88,90,92,94,96Zr, 93,94,95Nb and 179,181Ta have been investigated. The calculated results are discussed andcompared with the experimental data taken from the literature.

  20. Review of metastable states in heavy nuclei

    SciTech Connect

    Dracoulis, G. D.; Walker, P. M.; Kondev, F. G.

    2016-05-31

    Here, the structure of nuclear isomeric states is reviewed in the context of their role in contemporary nuclear physics research. Emphasis is given to high-spin isomers in heavy nuclei, with A ≳ 150. The possibility to exploit isomers to study some of the most exotic nuclei is a recurring theme. In spherical nuclei, the role of octupole collectivity is discussed in detail, while in deformed nuclei the limitations of the K quantum number are addressed. Isomer targets and isomer beams are considered, along with applications related to energy storage, astrophysics, medicine, and experimental advances.