WorldWideScience

Sample records for atomic nucleus

  1. Atom as a "Dressed" Nucleus

    CERN Document Server

    Kalitvianski, V

    2008-01-01

    It is shown that electrostatic potential of atomic nucleus seen by a fast charged projectile at short distances is quite smeared due to nucleus motion around the atomic center of inertia. For example, the size of positive charge cloud in the Hydrogen ground state is much larger than the proper proton size. It is even bigger for the target atom in an excited state. Therefore the elastic scattering at large angles is generally weaker than the Rutherford one. In other words, the resulting elastic interaction with an atom at short distances is softer than the Colombian one due to a natural cutoff. In addition, the large angle scattering leads to the target atom excitations due to hitting the nucleus (inelastic processes). It is also shown that the Rutherford cross section is in fact the inclusive rather than the elastic one. These results are analogous to the QED ones. The difference and the value of the presented below non relativistic atomic calculations is in non perturbatively (exact) dressing that immediatel...

  2. Contemporary models of the atomic nucleus

    CERN Document Server

    Nemirovskii, P E

    2013-01-01

    Contemporary Models of the Atomic Nucleus discusses nuclear structure and properties, expounding contemporary theoretical concepts of the low-energy nuclear processes underlying in nuclear models. This book focuses on subjects such as the optical nuclear model, unified or collective model, and deuteron stripping reaction. Other topics discussed include the basic nuclear properties; shell model; theoretical analysis of the shell model; and radiative transitions and alpha-decay. The deuteron theory and the liquid drop nuclear model with its application to fission theory are also mentioned, but o

  3. The Confined Hydrogen Atom with a Moving Nucleus

    Science.gov (United States)

    Fernandez, Francisco M.

    2010-01-01

    We study the hydrogen atom confined to a spherical box with impenetrable walls but, unlike earlier pedagogical articles on the subject, we assume that the nucleus also moves. We obtain the ground-state energy approximately by means of first-order perturbation theory and show that it is greater than that for the case in which the nucleus is clamped…

  4. Spin Symmetry for Anti-Lambda Spectrum in atomic nucleus

    CERN Document Server

    Song, Chunyan; Meng, Jie

    2009-01-01

    The spin symmetry of anti-Lambda spectrum in nucleus ^{16}O has been studied in the relativistic mean field theory. The spin-orbit splittings of spin doublets are found to be around 0.03-0.07 MeV and the dominant components of the Dirac spinor for the anti-Lambda spin doublets are found to be near identical. It indicates that there is an even better spin symmetry in the anti-Lambda spectrum than that in the anti-nucleon spectrum.

  5. Spin Symmetry for Anti-Lambda Spectrum in Atomic Nucleus

    Institute of Scientific and Technical Information of China (English)

    SONG Chun-Yan; YAO Jiang-Ming; MENG Jie

    2009-01-01

    The spin symmetry of the anti-Lambda spectrum in nucleus ~(16)O is studied in the relativistic mean field theory.The spin-orbit splittings of spin doublets are found to be around 0.03-0.07 MeV and the dominant components of the Dirac spinor for the anti-Lambda spin doublets are found to be near identical.It is indicated that there is an even better spin symmetry in the anti-Lambda spectrum than that in the anti-nucleon spectrum.

  6. Endohedrally confined hydrogen atom with a moving nucleus

    CERN Document Server

    Randazzo, Juan M

    2016-01-01

    We studied the hydrogen atom as a system of two quantum particles in different confinement conditions; a spherical-impenetrable-wall cavity and a fullerene molecule cage. The motion is referred to the center of spherical cavities, and the Schr\\"{o}dinger equation solved by means of a Generalized Sturmian Function expansion in spherical coordinates. The solutions present different properties from the ones described by the many models in the literature, where the proton is fixed in space and only the electron is considered as a quantum particle. Our results show that the position of the proton (i.e. the center of mas of the H atom) is very sensitive to the confinement condition, and could vary substantially from one state to another, from being sharply centered to being localized outside the fullerene molecule. Interchange of the localization characteristics between the states when varying the strength of the fullerene cage and mass occurred through crossing phenomena.

  7. Atomic mass dependence of hadron production in semi-inclusive deep inelastic lepton-nucleus scattering

    Institute of Scientific and Technical Information of China (English)

    SONG Li-Hua; LIU Na; DUAN Chun-Gui

    2013-01-01

    Hadron production in lepton-nucleus deep inelastic scattering is studied in a quark energy loss model.The leading-order computations for hadron multiplicity ratios are presented and compared with the selected HERMES pions production data with the quark hadronization occurring outside the nucleus by means of the hadron formation time.It is found that the obtained energy loss per unit length is 0.440±0.013 GeV/fm for an outgoing quark by the global fit.It is confirmed that the atomic mass number dependence of hadron attenuation is theoretically and experimentally in good agreement with the A2/3 power law for quark hadronization occurring outside the nucleus.

  8. Unravelling the Mystery of the Atomic Nucleus A Sixty Year Journey 1896 — 1956

    CERN Document Server

    Fernandez, Bernard

    2013-01-01

    Unravelling the Mystery of the Atomic Nucleus tells the story of how, in the span of barely sixty years, we made a transition from the belief that matter was composed of indivisible atoms, to the discovery that in the heart of each atom lies a nucleus which is ten thousand times smaller than the atom, which nonetheless carries almost all its mass, and the transformations of which involve energies that could never be reached by chemical reactions. It was not a smooth transition. The nature of nuclei, their properties, the physical laws which govern their behaviour, and the possibility of controlling to some extent their transformations, were discovered in discontinuous steps, following paths which occasionally led to errors which in turn were corrected by further experimental discoveries. The story begins in 1896 when radioactivity was unexpectedly discovered and continues up to the nineteen-sixties. The authors describe the spectacular progress made by physics during that time, which not only revealed a new f...

  9. Precision X-ray spectroscopy of kaonic atoms as a probe of low-energy kaon-nucleus interaction

    CERN Document Server

    Shi, H; Beer, G; Bellotti, G; Berucci, C; Bragadireanu, A M; Bosnar, D; Cargnelli, M; Curceanu, C; Butt, A D; d'Uffizi, A; Fiorini, C; Ghio, F; Guaraldo, C; Hayano, R S; Iliescu, M; Ishiwatari, T; Iwasaki, M; Sandri, P Levi; Marton, J; Okada, S; Pietreanu, D; Piscicchia, K; Vidal, A Romero; Sbardella, E; Scordo, A; Sirghi, D L; Sirghi, F; Tatsuno, H; Doce, O Vazquez; Widmann, E; Zmeskal, J

    2016-01-01

    In the exotic atoms where one atomic $1s$ electron is replaced by a $K^{-}$, the strong interaction between the $K^{-}$ and the nucleus introduces an energy shift and broadening of the low-lying kaonic atomic levels which are determined by only the electromagnetic interaction. By performing X-ray spectroscopy for Z=1,2 kaonic atoms, the SIDDHARTA experiment determined with high precision the shift and width for the $1s$ state of $K^{-}p$ and the $2p$ state of kaonic helium-3 and kaonic helium-4. These results provided unique information of the kaon-nucleus interaction in the low energy limit.

  10. P ,T -odd electron-nucleus interaction in atomic systems as an exchange by Higgs bosons

    Science.gov (United States)

    Chubukov, D. V.; Labzowsky, L. N.

    2016-06-01

    Scalar-pseudoscalar P ,T -odd interaction between the electron and the nucleus in atomic systems is constructed within the standard model as an exchange by Higgs boson. The necessary P - and T -violating contribution is obtained at the three-loop level on the basis of Cabibbo-Kobayashi-Maskawa matrix. This contribution, unlike the corresponding contribution to the electron electric dipole moment (EDM), does not vanish since the "Higgs charges" of quarks, contrary to their electric charges, are flavor dependent. Order-of-magnitude estimates of the effect expressed as an "equivalent" electron EDM give the values within the range deeqv˜10-40-10-45e cm , depending on the known different estimates for the electron EDM. This can be compared with the known "benchmark" two-photon P ,T -odd electron-nucleus interaction effect, which provides deeqv˜10-38e cm .

  11. A computer code for calculations in the algebraic collective model of the atomic nucleus

    CERN Document Server

    Welsh, T A

    2016-01-01

    A Maple code is presented for algebraic collective model (ACM) calculations. The ACM is an algebraic version of the Bohr model of the atomic nucleus, in which all required matrix elements are derived by exploiting the model's SU(1,1) x SO(5) dynamical group. This, in particular, obviates the use of coefficients of fractional parentage. This paper reviews the mathematical formulation of the ACM, and serves as a manual for the code. The code makes use of expressions for matrix elements derived elsewhere and newly derived matrix elements of the operators [pi x q x pi]_0 and [pi x pi]_{LM}, where q_M are the model's quadrupole moments, and pi_N are corresponding conjugate momenta (-2>=M,N<=2). The code also provides ready access to SO(3)-reduced SO(5) Clebsch-Gordan coefficients through data files provided with the code.

  12. 61. International conference NUCLEUS-2011 on problems of nuclear spectroscopy and structure of atomic nucleus. Book of abstracts

    International Nuclear Information System (INIS)

    The program of the 61th International conference NUCLEUS-2011 covers almost all actual problems of nuclear physics. The recent results of theoretical and experimental investigations of nuclear structure as well as nuclear reactions are presented. The fundamental problems of nuclear physics are discussed. The current achievements in the field of nuclear instrumentation and experimental techniques are considered. The considerable attention is given to modern nuclear databases as scientific research tools

  13. Superconductivity of the atomic nucleus and mechanism of memory and behaviour of the man

    International Nuclear Information System (INIS)

    unlimited information content and long duration of their memory. In necessary cases, after some interval of time (up to 150 ms) a brain can produce the required information for acceptance of an operation relevant for the given exterior circumstances. Comparison the physicochemical properties of hierarchy of devices, - fundamental particles up to super composite biological molecules, to consider that only atomic nucleus, which has properties of a superconductivity, can be maintained with the information long-lived time. An entry of the information to be carried out a holographic mode. The arguing of process of an entry of the information in a brain requires an improvement of property of enclosing space through which the information is transmitted. According to density of space vacuum much more exceeds the density if an energy of the atomic nucleus. Therefore structural-dynamic processes in substances, including problem of memory cannot be discussed without the account of field-substance interaction. In substances, including in alive plants the inserted and imposed each other hierarchies are shaped is relative of self-consistent fields of fundamentals particles, atomic nuclei, atoms and molecules. The modification of energy structure of each of them renders influence an properties of others. However only self-consistent field of atomic nuclei possessing property of superconductivity, can for a long time maintain the information of past events. In this connection there is a natural problem on the mechanism of an entry and extraction of the information in the atomic nuclei. Utilizing the basic position of a holography it is possible to consider the atomic nucleus as the volumetric hologram. The alive entities, including Man are in a high-frequency field of perfect vacuum. Therefore properties of an oscillation of a perfect vacuum play a role of a reference wave. The information acting through visual organs or on other channels of sensitivity to exterior actions raise alarm

  14. Generalized boson model and α-cluster states of 44Ti atomic nucleus

    International Nuclear Information System (INIS)

    At present some rotational bands for the 44Ti atomic nucleus with a sequence of spins and parities are discovered. For an analysis of these bands the generalized boson model U(6) direct X U(4) including the collective (quadrupole) degree of freedom and cluster (dipole) variable as well as an inter-relation of quadrupole and dipole degrees of freedom is used. Different collective bands of U(6) direct X SU(3) model reduction are considered as well. Parameter of SU(3) symmetrical Hamiltonian are equal to k=0.0016 MeV. (3/4k-k')=0.085 MeV. The U(4)contains U(3)-symmetry, caused by dipole clusterization of nucleons, describes bands of α-cluster states kπ=04+,02-, with theoretical parameters E0=-11 MeV, εp=0.1 MeV, β=0.15 MeV. An interaction of the cluster (dipole) degree with he quadrupole one allows to explain the band of parity, kπ=01-, beginning with E=6.22 MeV by values of parameters of kp=0, γ=6.2 MeV

  15. A computer code for calculations in the algebraic collective model of the atomic nucleus

    Science.gov (United States)

    Welsh, T. A.; Rowe, D. J.

    2016-03-01

    A Maple code is presented for algebraic collective model (ACM) calculations. The ACM is an algebraic version of the Bohr model of the atomic nucleus, in which all required matrix elements are derived by exploiting the model's SU(1 , 1) × SO(5) dynamical group. This paper reviews the mathematical formulation of the ACM, and serves as a manual for the code. The code enables a wide range of model Hamiltonians to be analysed. This range includes essentially all Hamiltonians that are rational functions of the model's quadrupole moments qˆM and are at most quadratic in the corresponding conjugate momenta πˆN (- 2 ≤ M , N ≤ 2). The code makes use of expressions for matrix elements derived elsewhere and newly derived matrix elements of the operators [ π ˆ ⊗ q ˆ ⊗ π ˆ ] 0 and [ π ˆ ⊗ π ˆ ] LM. The code is made efficient by use of an analytical expression for the needed SO(5)-reduced matrix elements, and use of SO(5) ⊃ SO(3) Clebsch-Gordan coefficients obtained from precomputed data files provided with the code.

  16. An extremely important discovery-the centre of the electron cloud of K atom does not coincide with the nucleus

    CERN Document Server

    You, Pei-Lin

    2009-01-01

    It is a general point of view that in the absence of an external field, the nucleus of an atom is at the centre of the electron cloud, so that all kinds of atoms do not have permanent electric dipole moment(EDM). In the fact, the idea is untested. Using two special capacitors containing Potassium vapor we discovered that the electric susceptibility Xe of K atoms is directly proportional to the density N, and inversely to the temperature T, as polar molecules. The experimental K material is supplied by Strem Chemicals Co. USA. We have distinguished between permanent and induced dipole moments carefully. There is good evidence that a ground state neutral K atom has a large permanent EDM, d(K)=2.53*10-29C.m, while d(H2O)=0.62 *10-29C.m for water molecule. New example of time-reversal violation occurred in K atoms. Why the linear Stark effect of K atoms has not been observed? The article discussed the question thoroughly. The linear Stark shift of K atoms is only 0.0041nm. It is so small, in fact, that a direct o...

  17. Cloud condensation nucleus (CCN behavior of organic aerosol particles generated by atomization of water and methanol solutions

    Directory of Open Access Journals (Sweden)

    T. A. Rissman

    2007-06-01

    Full Text Available Cloud condensation nucleus (CCN experiments were carried out for malonic acid, succinic acid, oxalacetic acid, DL-malic acid, glutaric acid, DL-glutamic acid monohydrate, and adipic acid, using both water and methanol as atomization solvents, at three operating supersaturations (0.11%, 0.21%, and 0.32% in the Caltech three-column CCN instrument (CCNC3. Predictions of CCN behavior for five of these compounds were made using the Aerosol Diameter Dependent Equilibrium Model (ADDEM. The experiments presented here expose important considerations associated with the laboratory measurement of the CCN behavior of organic compounds. Choice of atomization solvent results in significant differences in CCN activation for some of the compounds studied, which could result from residual solvent, particle morphology differences, and chemical reactions between the particle and gas phases. Also, significant changes in aerosol size distribution occurred after classification in a differential mobility analyzer (DMA for malonic acid and glutaric acid, preventing confident interpretation of experimental data for these two compounds. Filter analysis of adipic acid atomized from methanol solution indicates that gas-particle phase reactions may have taken place after atomization and before methanol was removed from the sample gas stream. Careful consideration of these experimental issues is necessary for successful design and interpretation of laboratory CCN measurements.

  18. Cloud condensation nucleus (CCN behavior of organic aerosol particles generated by atomization of water and methanol solutions

    Directory of Open Access Journals (Sweden)

    T. A. Rissman

    2006-12-01

    Full Text Available Cloud condensation nucleus (CCN experiments were carried out for malonic acid, succinic acid, oxalacetic acid, DL-malic acid, glutaric acid, DL-glutamic acid monohydrate, and adipic acid, using both water and methanol as atomization solvents, at three operating supersaturations (0.11% 0.21%, and 0.32% in the Caltech three-column CCN instrument (CCNC3. Predictions of CCN behavior for five of these compounds were made using the Aerosol Diameter Dependent Equilibrium Model (ADDEM. The experiments presented here expose important considerations associated with the laboratory measurement of the CCN behavior of organic compounds. Choice of atomization solvent results in significant differences in CCN activation for some of the compounds studied, which could result from residual solvent, particle morphology differences, and chemical reactions between the particle and gas phases. Also, significant changes in aerosol size distribution occurred after classification in a differential mobility analyzer (DMA for malonic acid and glutaric acid. Filter analysis of adipic acid atomized from methanol solution indicates that gas-particle phase reactions may have taken place after atomization and before the methanol was removed from the sample gas stream. Careful consideration of these experimental issues is necessary for successful design and interpretation of laboratory CCN measurements.

  19. Cloud condensation nucleus (CCN) behavior of organic aerosol particles generated by atomization of water and methanol solutions

    Science.gov (United States)

    Rissman, T. A.; Varutbangkul, V.; Surratt, J. D.; Topping, D. O.; McFiggans, G.; Flagan, R. C.; Seinfeld, J. H.

    2007-06-01

    Cloud condensation nucleus (CCN) experiments were carried out for malonic acid, succinic acid, oxalacetic acid, DL-malic acid, glutaric acid, DL-glutamic acid monohydrate, and adipic acid, using both water and methanol as atomization solvents, at three operating supersaturations (0.11%, 0.21%, and 0.32%) in the Caltech three-column CCN instrument (CCNC3). Predictions of CCN behavior for five of these compounds were made using the Aerosol Diameter Dependent Equilibrium Model (ADDEM). The experiments presented here expose important considerations associated with the laboratory measurement of the CCN behavior of organic compounds. Choice of atomization solvent results in significant differences in CCN activation for some of the compounds studied, which could result from residual solvent, particle morphology differences, and chemical reactions between the particle and gas phases. Also, significant changes in aerosol size distribution occurred after classification in a differential mobility analyzer (DMA) for malonic acid and glutaric acid, preventing confident interpretation of experimental data for these two compounds. Filter analysis of adipic acid atomized from methanol solution indicates that gas-particle phase reactions may have taken place after atomization and before methanol was removed from the sample gas stream. Careful consideration of these experimental issues is necessary for successful design and interpretation of laboratory CCN measurements.

  20. First Atomic Electric Dipole Moment Limit Derived from an Octupole-Deformed Nucleus

    Science.gov (United States)

    Parker, Richard; Bishof, Michael; Kalita, Mukut; Lemke, Nathan; Dietrich, Matt; Bailey, Kevin; Greene, John; Holt, Roy; Korsch, Wolfgang; Lu, Zheng-Tian; Mueller, Peter; O'Connor, T. P.; Singh, Jaideep

    2015-05-01

    Ra-225 (half-life = 15 d, nuclear spin = 1/2) is a promising isotope for a measurement of the EDM of a diamagnetic atom. Due to its large nuclear octupole deformation and high atomic mass, the EDM sensitivity of Ra-225 is expected to be 2-3 orders of magnitude larger than that of Hg-199. We demonstrate an efficient multiple-stage apparatus in which radium atoms are first loaded into a MOT, then transferred into a movable optical-dipole trap (ODT) that carries the atoms over 1 m to a magnetically-shielded science chamber, loaded into a standing-wave ODT, polarized, and then allowed to precess in magnetic and electric fields. We will discuss our first measurement of the EDM of Ra-225, as well as plans for future improvements. This work is supported by DOE, Office of Nuclear Physics (DE-AC02-06CH11357).

  1. Nuclear research in 2014 summer school special issue. How do see the spin-isospin symmetry of the atomic nucleus?

    International Nuclear Information System (INIS)

    This paper introduces the experiment, where the function of spin-isospin symmetry inside atomic nuclei was observed through Gamow-Teller (GT) transition. In the experiment, the authors used 56Ni (p,n) reaction as inverse kinematics using the intermediate energy unstable nucleus beams, and missing mass method to obtain the GT transition intensity distribution of unstable nucleus 56Ni. In the missing mass method, by measuring the four momentum vector (kinetic energy and emission direction) of the recoil neutrons from the probe particles produced in the (p,n) reaction, excitation energy and scattering angle are determined. When the experimental results were compared with the full-fp shell model calculation called as GXPFiL interaction, two peaks characteristic of the experimental data were well reproduced. In the GT transition strength distribution of 56Ni, half of the intensities concentrated in the peaks of the low-energy side, and explanation was impossible based on the effect of particle vacancy interaction. However, in N=Z nuclei, particle-particle interactions was emphasized, which suggests the situation for some intensities to make the peaks at the low excitation energy side. (A.O.)

  2. First clear evidence of quantum chaos in the bound states of an atomic nucleus

    CERN Document Server

    Muñoz, L; Gómez, J M G; Heusler, A

    2016-01-01

    We study the spectral fluctuations of the $^{208}$Pb nucleus using the complete experimental spectrum of 151 states up to excitation energies of $6.20$ MeV recently identified at the Maier-Leibnitz-Laboratorium at Garching, Germany. For natural parity states the results are very close to the predictions of Random Matrix Theory (RMT) for the nearest-neighbor spacing distribution. A quantitative estimate of the agreement is given by the Brody parameter $\\omega$, which takes the value $\\omega=0$ for regular systems and $\\omega \\simeq 1$ for chaotic systems. We obtain $\\omega=0.85 \\pm 0.02$ which is, to our knowledge, the closest value to chaos ever observed in experimental bound states of nuclei. By contrast, the results for unnatural parity states are far from RMT behavior. We interpret these results as a consequence of the strength of the residual interaction in $^{208}$Pb, which, according to experimental data, is much stronger for natural than for unnatural parity states. In addition our results show that ch...

  3. Complex wave-interference phenomena: From the atomic nucleus to mesoscopic systems to microwave cavities

    Indian Academy of Sciences (India)

    Pier A Mello

    2001-02-01

    Universal statistical aspects of wave scattering by a variety of physical systems ranging from atomic nuclei to mesoscopic systems and microwave cavities are described. A statistical model for the scattering matrix is employed to address the problem of quantum chaotic scattering. The model, introduced in the past in the context of nuclear physics, discusses the problem in terms of a prompt and an equilibrated component: it incorporates the average value of the scattering matrix to account for the prompt processes and satisfies the requirements of flux conservation, causality and ergodicity. The main application of the model is the analysis of electronic transport through ballistic mesoscopic cavities: it describes well the results from the numerical solutions of the Schrödinger equation for two-dimensional cavities.

  4. Study of the octupole modes in the atomic nucleus of 156Gd: experimental search of the tetrahedral symmetry

    International Nuclear Information System (INIS)

    Geometrical symmetries play an important role in the understanding of all physical systems. In nuclear structure they are linked to the shape of the mean-field used to describe the atomic nuclei properties. In the framework of this thesis, we have used the predictions obtained with the help of the nuclear mean-field Hamiltonian with the Universal Woods-Saxon potential to study the effects of the so-called 'High-Rank' symmetries. These point-group symmetries lead to a nuclear state degeneracy of the order of 4. It is predicted that the tetrahedral symmetry affects the stability of nuclei close to the tetrahedral magic numbers [Z,N]=[32,40,56,64,70,90-94,136]. We have selected the Rare-Earth region close to the tetrahedral doubly magic nucleus 154Gd for our study. In this region, there exists negative parity structures poorly understood. Yet the tetrahedral symmetry, as related to a non-axial octupole deformation, breaks the reflection symmetry and leads to the negative parity states. Following a systematics of experimental properties of the nuclei in this region, we have selected 156Gd as the object of our study for the octupole excitation modes. We have used the reduced transitions probabilities to discriminate between these modes. To achieve this goal, we have performed three gamma spectroscopy experiments at the ILL in Grenoble with the EXILL and GAMS detectors to measure the lifetimes and the gamma transition intensities from the candidate states. The analysis of our results shows that including the tetrahedral shape helps to understand the dipole transition probabilities. This result will open new experimental and theoretical perspectives. (author)

  5. The estimation of production rates of {\\pi }^{+}{K}^{-}, {\\pi }^{-}{K}^{+} and {\\pi }^{+}{\\pi }^{-} atoms in proton-nucleus interactions at 450 GeV c-1

    Science.gov (United States)

    Gorchakov, O. E.; Nemenov, L. L.

    2016-09-01

    Short-lived (τ ˜ 3× {10}-15 s) {π }+{K}-, {K}+{π }- and {π }+{π }- atoms as well as long-lived (τ ≥slant 1× {10}-11 s) {π }+{π }- atoms produced in proton-nucleus interactions at 24 GeV c-1 are observed and studied in the DIRAC experiment at the CERN Proton Synchroton. The purpose of this paper is to show that the yields of the short-lived {π }+{K}-, {K}+{π }- and {π }+{π }- atoms in proton-nucleus interactions at 450 GeV c-1 and {θ }{{lab}}=4^\\circ are estimated to be, respectively 67 ± 13, 31 ± 6 and 15 ± 2 times higher. This may allow a significant improvement of the precision of their lifetime measurement and π π and π K scattering length combinations | {a}0-{a}2| and | {a}1/2-{a}3/2| . The yields of the long-lived {π }+{K}-, {K}+{π }- and {π }+{π }- atoms at 450 GeV c-1 are estimated to be 265 ± 53, 120 ± 24 and 60 ± 9 times higher per time unit than at 24 GeV c-1. This may allow the resonance method to be used for measuring the Lamb shift in the π π atom and a new π π scattering length combination 2{a}0+{a}2 to be obtained.

  6. Atomic Number Dependence of Hadron Production at Large Transverse Momentum in 300 GeV Proton--Nucleus Collisions

    Science.gov (United States)

    Cronin, J. W.; Frisch, H. J.; Shochet, M. J.; Boymond, J. P.; Mermod, R.; Piroue, P. A.; Sumner, R. L.

    1974-07-15

    In an experiment at the Fermi National Accelerator Laboratory we have compared the production of large transverse momentum hadrons from targets of W, Ti, and Be bombarded by 300 GeV protons. The hadron yields were measured at 90 degrees in the proton-nucleon c.m. system with a magnetic spectrometer equipped with 2 Cerenkov counters and a hadron calorimeter. The production cross-sections have a dependence on the atomic number A that grows with P{sub 1}, eventually leveling off proportional to A{sup 1.1}.

  7. Atoms

    Institute of Scientific and Technical Information of China (English)

    刘洪毓

    2007-01-01

    Atoms(原子)are all around us.They are something like the bricks (砖块)of which everything is made. The size of an atom is very,very small.In just one grain of salt are held millions of atoms. Atoms are very important.The way one object acts depends on what

  8. The estimation of production rates of $π^+ K^−, π^− K^+$ and $π^+π^−$ atoms in proton-nucleus interactions at 24 and 450 GeV/c

    CERN Document Server

    Gorchakov, O

    2016-01-01

    Short-lived ( τ ∼ 3 × 10 − 15 s ) π + K − , K + π − and π + π − atoms as well as long-lived ( τ ≥ 1 × 10 − 11 s) π + π − atoms produced in proton-nucleus interactions at 24 GeV/c are observed and studied in the DIRAC experiment at the CERN P S. The purpose of this paper is to show that the yields of the short-lived π + K − , K + π − and π + π − atoms in proton-nucleus interactions at 450 GeV/c and θ lab = 4 ◦ are estimated to be, respectively, 17, 38 and 16 times higher. This may allow sign ificantly improving the precision of their lifetime measurement and ππ and πK scattering length combinations | a 0 − a 2 | and | a 1 / 2 − a 3 / 2 | . The yields of the long-lived π + K − , K + π − and π + π − atoms at 450 GeV/c are estimated to be 180,800 and 370 times higher p er time unit than at 24 GeV/c. This may allow the resonance method to be used for measuring the Lamb shift in the ππ atom and a new ππ scattering length combination 2a0 + a2 to be obtaine...

  9. Kaonic nuclei and kaon-nucleus interactions

    CERN Document Server

    Ikuta, K; Masutani, K

    2002-01-01

    Although kaonic atoms provide valuable information concerning the K sup - -nucleus interaction at low energies, they cannot fully determine the K sup - - nucleus optical potential. We demonstrate that K sup - nuclear bound states, if they exist, can be useful in investigating the K sup - -nucleus interaction, especially in the interior of the nucleus. In order to show this possibility, we calculate the double differential cross sections for (K sup - , P) using the Green function method. (author)

  10. Atomic inner shell ionization: a new method of nuclear interaction lifetimes in the range 10-16-10-18 second. Lifetime measurement of the compound nucleus in the reaction 106Cd+p (Ep=10 and 12 MeV)

    International Nuclear Information System (INIS)

    A new method to measure the lifetime of the compound nucleus formed in the reaction 106Cd+p at Ep=10 and 12 MeV is described. The nuclear lifetime is compared to the known lifetime of an atomic inner shell vacancy created in the entrance channel of the nuclear reaction. If the ionization probability in he way-in of the nuclear reaction is kown the compound nucleus lifetime is deduced by a simple relation from the number of compound X-rays measured in coincidence with one of the reaction products. A large number of ionization probability values measured in very small impact parameter collisions induced by H+, He+, D+ on Al, Cu, S, Ti, Si, Ag, Cd are reported. The data are interpreted in terms of the corrected SCA theory of ionization. New effects such as angular dependence and trajectory effect (hair-pin-curve effect) are shown experimentally. The influence of a nuclear delay time on the ionization probability value is considered; the effect on a nuclear reaction of the energy losses by the projectile during the ionization process is analysed in detail. The yield curve of the resonant nuclear reaction 27Al(p,γ)28Si is taken as an example. A detailed analysis of the compound nucleus 107In lifetimes is given. Attention has been paid to competitive processes leading to X ray emission of same energy as the compound X rays. Extensions of the method to measure compound nucleus lifetimes in collision induced by heavy ions and to separate the shape elastic and compound elastic mechanisms are presented

  11. Atomic Energy Basics, Understanding the Atom Series.

    Science.gov (United States)

    Atomic Energy Commission, Oak Ridge, TN. Div. of Technical Information.

    This booklet is part of the "Understanding the Atom Series," though it is a later edition and not included in the original set of 51 booklets. A basic survey of the principles of nuclear energy and most important applications are provided. These major topics are examined: matter has molecules and atoms, the atom has electrons, the nucleus,…

  12. A radio jet drives a molecular & atomic gas outflow in multiple regions within one square kiloparsec of the nucleus of the nearby galaxy IC5063

    CERN Document Server

    Dasyra, K M; Combes, F; Vlahakis, N

    2015-01-01

    We analyzed near-infrared data of the nearby galaxy IC5063 taken with the Very Large Telescope SINFONI instrument. IC5063 is an elliptical galaxy that has a radio jet nearly aligned with the major axis of a gas disk in its center. The data reveal multiple signatures of molecular and atomic gas that has been kinematically distorted by the jet passage within an area of ~1 kpc^2. Concrete evidence that the impact of jet plasma upon gas causes the gas to accelerate comes from outflows detected near four different bending points of the jet: at the two bright radio lobes, near a diverted plasma stream close to the north lobe, and near the tip of a plasma stream in the narrow-line region. Gas moving with a velocity excess of 600 km/s to 1200 km/s with respect to ordered motions is detected in [FeII], Paa, and H2 lines. Around these regions, gas is scattered in different directions. Near the north lobe, the highly blueshifted and the highly redshifted [FeII] emission is offset by 240 pc. The (scattered or not) plasma...

  13. Into the atom and beyond

    CERN Multimedia

    1989-01-01

    Magnifying an atom to football pitch size. The dense nucleus, carrying almost all the atomic mass, is much smaller than the ball. The players (the electrons) would see something about the size of a marble!

  14. The atomic nucleus%原子核

    Institute of Scientific and Technical Information of China (English)

    T.Shipman

    2004-01-01

    Einstein's equation, E= mc2, which relates mass to energy, has been known since 1905. But its important to the human race was not realized until 1939. In December of 1938 German scientists showed that,conditlons, uraniumqual parts withatoms would splitthe accompanyingunder appropriate into two approximately erelease of large amount of

  15. Nuclear effects in atomic transitions

    OpenAIRE

    Pálffy, Adriana

    2011-01-01

    Atomic electrons are sensitive to the properties of the nucleus they are bound to, such as nuclear mass, charge distribution, spin, magnetization distribution, or even excited level scheme. These nuclear parameters are reflected in the atomic transition energies. A very precise determination of atomic spectra may thus reveal information about the nucleus, otherwise hardly accessible via nuclear physics experiments. This work reviews theoretical and experimental aspects of the nuclear effects ...

  16. Photon Exchange in Nucleus-Nucleus Collisions

    OpenAIRE

    Bertulani, Carlos A.

    2002-01-01

    The strong electromagnetic fields in peripheral heavy ion collisions give rise to photon-photon and photon-nucleus interactions. I present a general survey of the photon-photon and photon-hadron physics accessible in these collisions. Among these processes I discuss the nuclear fragmentation through the excitation of giant resonances, the Coulomb dissociation method for application in nuclear astrophysics, and the production of particles.

  17. Examination of the fission time of the Z =120 nucleus

    Science.gov (United States)

    Sikdar, A. K.; Ray, A.; Chatterjee, A.

    2016-04-01

    We show that the large difference in the measured lifetime for asymmetric fission of the highly excited (T ≈1.5 -MeV ) Z =120 nucleus as measured by the atomic techniques (crystal blocking and x-ray methods) with those measured by the nuclear techniques (mass-angle distribution and prefission neutron multiplicity) cannot be due to the different sensitivities of the atomic and nuclear techniques in different time domains. The claim of formation of a superheavy Z =120 nucleus with a high fission barrier on the basis of an observed long fission time by the atomic techniques is in direct conflict with all other available measurements and calculations.

  18. Antibaryon-nucleus bound states

    CERN Document Server

    Hrtánková, J

    2014-01-01

    We calculated antibaryon ($\\bar{B}$ = $\\bar{p}$, $\\bar{\\Lambda}$, $\\bar{\\Sigma}$, $\\bar{\\Xi}$) bound states in selected nuclei within the relativistic mean-field (RMF) model. The G-parity motivated $\\bar{B}$-meson coupling constants were scaled to yield corresponding potentials consistent with available experimental data. Large polarization of the nuclear core caused by $\\bar{B}$ was confirmed. The $\\bar{p}$ annihilation in the nuclear medium was incorporated by including a phenomenological imaginary part of the optical potential. The calculations using a complex $\\bar{p}$-nucleus potential were performed fully self-consistently. The $\\bar{p}$ widths significantly decrease when the phase space reduction is considered for $\\bar{p}$ annihilation products, but they still remain sizeable for potentials consistent with $\\bar{p}$-atom data.

  19. Nuclear effects in atomic transitions

    CERN Document Server

    Pálffy, Adriana

    2011-01-01

    Atomic electrons are sensitive to the properties of the nucleus they are bound to, such as nuclear mass, charge distribution, spin, magnetization distribution, or even excited level scheme. These nuclear parameters are reflected in the atomic transition energies. A very precise determination of atomic spectra may thus reveal information about the nucleus, otherwise hardly accessible via nuclear physics experiments. This work reviews theoretical and experimental aspects of the nuclear effects that can be identified in atomic structure data. An introduction to the theory of isotope shifts and hyperfine splitting of atomic spectra is given, together with an overview of the typical experimental techniques used in high-precision atomic spectroscopy. More exotic effects at the borderline between atomic and nuclear physics, such as parity violation in atomic transitions due to the weak interaction, or nuclear polarization and nuclear excitation by electron capture, are also addressed.

  20. Enhancement of φ Mesons in Relativistic Nucleus-Nucleus Collisions

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The фmeson production in relativistic nucleus-nucleus collisions is investigated systematically usinga hadron-string cascade model LUCIAE. Within the framework of the model and relying on the collective

  1. Atomic Particle Detection

    Energy Technology Data Exchange (ETDEWEB)

    Hellman, Hal

    1970-01-01

    This booklet tells how scientists observe the particles and electromagnetic radiation that emerges from an atomic nucleus. The equipment used falls into two general categories: counters which count each particle as it passes by, and track detectors, which make a photographic record of the particle's track.

  2. Neutrino nucleus cross sections

    CERN Document Server

    Athar, M Sajjad; Singh, S K; Vacas, M J Vicente

    2008-01-01

    We present the results of our calculation which has been performed to study the nuclear effects in the quasielastic, inelastic and deep inelastic scattering of neutrinos(antineutrinos) from nuclear targets. These calculations are done in the local density approximation. We take into account the effect of Pauli blocking, Fermi motion, Coulomb effect, renormalization of weak transition strengths in the nuclear medium in the case of the quasielastic reaction. The inelastic reaction leading to production of pions is calculated in a $\\Delta $- dominance model taking into account the renormalization of $\\Delta$ properties in the nuclear medium and the final state interaction effects of the outgoing pions with the residual nucleus. We discuss the nuclear effects in the $F_{3}^{A}(x)$ structure function in the deep inelastic neutrino(antineutrino) reaction using a relativistic framework to describe the nucleon spectral function in the nucleus.

  3. Polarized Proton Nucleus Scattering

    OpenAIRE

    Kopeliovich, B. Z.; Trueman, T. L.

    2000-01-01

    We show that, to a very good approximation, the ratio of the spin-flip to the non-flip parts of the elastic proton-nucleus amplitude is the same as for proton-nucleon scattering at very high energy. The result is used to do a realistic calculation of the analyzing power A_N for pC scattering in the Coulomb-nuclear interference (CNI) region of momentum transfer.

  4. Hadron nucleus interactions

    International Nuclear Information System (INIS)

    The elastic and inelastic scattering of intermediate energy (less than or equal to 1 GeV) protons by nuclei is considered first. The discussion focuses on the determination of the proton-nucleus optical potential in terms of the elementary nucleon-nucleon scattering amplitudes and the properties of the target and residual nucleus. The result is a series of terms for the optical potential. Then the interaction of pions with nuclei for energies in the neighborhood of the Δ-resonance is discussed. In this energy domain an incident pion will with high probability be absorbed by a nucleon to produce the Δ-resonance and thus form a Δ-particle hole state in the nucleus. Next, the subject of hypernuclei is taken up. The Λ hypernuclei and a recently observed Σ hypernuclei comprise situations in which the core nucleus can be probed by a baryon of roughly the same mass as a nucleon, with similar albeit not identical interactions with nucleons. But the Λ (or Σ) does not need to satisfy the Pauli exclusion principle with respect to the nucleons, and therefore can be in orbits forbidden to it if it were a nucleon. As the energy of the projectile increases, it becomes correspondingly more important to take relativistic effects into account. The importance of these effects is strikingly revealed by experiments involving the collision of ultrarelativistic hadrons, protons, pions, kaons (up to Fermilab energies) with nuclei. This phenomenon forms part of the final topic, which includes as well as the collision of relativistic heavy ion projectiles with nuclei. A nuclear Weiszaecker-Williams method developed for dealing with peripheral collisions is described. 32 figures, 10 tables

  5. Antinucleon-nucleus interactions

    Energy Technology Data Exchange (ETDEWEB)

    Dover, C.B.

    1987-01-01

    Recent experimental and theoretical results on anti p-nucleus interactions are reviewed. We focus on determinations of the anti p optical potential from elastic scattering, the use of (anti p, anti p') inelastic scattering to reveal aspects of the spin-isospin dependence of N anti N amplitudes, and some puzzling features of (anti p, anti n) charge exchange reactions on nuclei. 47 refs., 7 figs.

  6. About possibility to search the electron EDM at the level $10^{-28} \\div 10^{-30}$ e$\\cdot$cm and the constant of T-odd, P-odd scalar weak interaction of an electron with a nucleus at the level $10^{-5} \\div 10^{-7}$ in the heavy atoms and ferroelectrics

    CERN Document Server

    Baryshevsky, V G

    2005-01-01

    The T-odd phenomenon of induction of the magnetic field by a static electric field provides to study the electron EDM and constants of T-odd, P-odd interaction of an electron with a nucleus. Measurement of this magnetic field for ferroelectric materials (like PbTiO_3) at the level B~3 10^{-18} G allows to derive the electric dipole moment of an electron at the level d_e ~ 10^{-30} e cm and the constant of T-odd scalar weak interaction of an electron with a nucleus at the level k_1^{nuc}10^{-9}. The atomic magnetometry makes possible to measure fields ~ 10^{-13} G/\\sqrt{Hz} now. This means that for 10 days operation one can expect to obtain B at the level B ~ 10^{-16}G, and, therefore, the limits for d_e in PbTiO_3 at the level d_e ~ 10^{-28} and k_1^{nuc}~10^{-7}. that makes the discussed method beneficial for measuring d_e and k_1^{nuc}.

  7. Neutrino-nucleus interactions

    Energy Technology Data Exchange (ETDEWEB)

    Gallagher, H.; /Tufts U.; Garvey, G.; /Los Alamos; Zeller, G.P.; /Fermilab

    2011-01-01

    The study of neutrino oscillations has necessitated a new generation of neutrino experiments that are exploring neutrino-nuclear scattering processes. We focus in particular on charged-current quasi-elastic scattering, a particularly important channel that has been extensively investigated both in the bubble-chamber era and by current experiments. Recent results have led to theoretical reexamination of this process. We review the standard picture of quasi-elastic scattering as developed in electron scattering, review and discuss experimental results, and discuss additional nuclear effects such as exchange currents and short-range correlations that may play a significant role in neutrino-nucleus scattering.

  8. Antineutron-nucleus annihilation

    CERN Document Server

    Botta, E

    2001-01-01

    The n-nucleus annihilation process has been studied by the OBELIX experiment at the CERN Low Energy Antiproton Ring (LEAR) in the (50-400) MeV/c projectile momentum range on C, Al, Cu, Ag, Sn, and Pb nuclear targets. A systematic survey of the annihilation cross- section, sigma /sub alpha /(A, p/sub n/), has been performed, obtaining information on its dependence on the target mass number and on the incoming n momentum. For the first time the mass number dependence of the (inclusive) final state composition of the process has been analyzed. Production of the rho vector meson has also been examined. (13 refs).

  9. Nucleus-nucleus potential with shell-correction contribution

    CERN Document Server

    Denisov, V Yu

    2015-01-01

    The full relaxed-density potential between spherical nuclei is considered as a sum of the macroscopic and shell-correction contributions. The macroscopic part of the potential is related to a nucleus-nucleus potential obtained in the framework of the extended Thomas-Fermi approach with the Skyrme and Coulomb forces and the relaxed-density ansatz for evaluation of proton and neutron densities of interacting nuclei. A simple prescription for the shell-correction part of the total potential is discussed. The parameters of the shell-correction and macroscopic parts of the relaxed-density potential are found by fitting the empirical barrier heights of the 89 nucleus-nucleus systems as well as macroscopic potentials evaluated for 1485 nucleus-nucleus systems at 12 distances around touching points.

  10. Higgs-Boson Production in Nucleus-Nucleus Collisions

    Science.gov (United States)

    Norbury, John W.

    1992-01-01

    Cross section calculations are presented for the production of intermediate-mass Higgs bosons produced in ultrarelativistic nucleus-nucleus collisions via two photon fusion. The calculations are performed in position space using Baur's method for folding together the Weizsacker-Williams virtual-photon spectra of the two colliding nuclei. It is found that two photon fusion in nucleus-nucleus collisions is a plausible way of finding intermediate-mass Higgs bosons at the Superconducting Super Collider or the CERN Large Hadron Collider.

  11. Radionuclide generator having first and second atoms of a first element

    NARCIS (Netherlands)

    Bode, P.; Wolterbeek, H.T.; De Vries, D.J.; De Bruin, M.

    2013-01-01

    The invention is in the field of a radionuclide generator. A radionuclide is an atom with an unstable nucleus, which is a nucleus characterized by excess energy available to be imparted either to a newly created radiation particle within the nucleus or to an atomic electron. Radionuclide generators

  12. Nucleus-independent chemical shift criterion for aromaticity in Π-extended tetraoxa[8]circulenes

    DEFF Research Database (Denmark)

    Baryshnikov, Gleb V.; Minaev, Boris F.; Pittelkow, Michael;

    2013-01-01

    Recently synthesized p-extended symmetrical tetraoxa[8]circulenes that exhibit electroluminescent properties were calculated at the density functional theory (DFT) level using the quantum theory of atoms in molecules (QTAIM) approach to electron density distribution analysis. Nucleus-independent ...

  13. Kinetic and Exchange Energy Densities near the Nucleus

    Directory of Open Access Journals (Sweden)

    Lucian A. Constantin

    2016-04-01

    Full Text Available We investigate the behavior of the kinetic and the exchange energy densities near the nuclear cusp of atomic systems. Considering hydrogenic orbitals, we derive analytical expressions near the nucleus, for single shells, as well as in the semiclassical limit of large non-relativistic neutral atoms. We show that a model based on the helium iso-electronic series is very accurate, as also confirmed by numerical calculations on real atoms up to two thousands electrons. Based on this model, we propose non-local density-dependent ingredients that are suitable for the description of the kinetic and exchange energy densities in the region close to the nucleus. These non-local ingredients are invariant under the uniform scaling of the density, and they can be used in the construction of non-local exchange-correlation and kinetic functionals.

  14. D- mesic atoms

    Science.gov (United States)

    García-Recio, C.; Nieves, J.; Salcedo, L. L.; Tolos, L.

    2012-02-01

    The anti-D meson self-energy is evaluated self-consistently, using unitarized coupled-channel theory, by computing the in-medium meson-baryon T matrix in the C=-1,S=0 sector. The heavy pseudo-scalar and heavy vector mesons, D¯ and D¯*, are treated on equal footing as required by heavy-quark spin symmetry. Results for energy levels and widths of D- mesic atoms in 12C, 40Ca, 118Sn, and 208Pb are presented. The spectrum contains states of atomic and of nuclear types for all nuclei. D¯0-nucleus bound states are also obtained. We find that, after electromagnetic and nuclear cascade, these systems end up with the D¯ bound in the nucleus, either as a meson or as part of an exotic D¯N (pentaquark) loosely bound state.

  15. Neurons of human nucleus accumbens

    Directory of Open Access Journals (Sweden)

    Sazdanović Maja

    2011-01-01

    Full Text Available Background/Aim. Nucleus accumbens is a part of the ventral striatum also known as a drug active brain region, especially related with drug addiction. The aim of the study was to investigate the Golgi morphology of the nucleus accumbens neurons. Methods. The study was performed on the frontal and sagittal sections of 15 human brains by the Golgi Kopsch method. We classified neurons in the human nucleus accumbens according to their morphology and size into four types: type I - fusiform neurons; type II - fusiform neurons with lateral dendrite, arising from a part of the cell body; type III - pyramidal-like neuron; type IV - multipolar neuron. The medium spiny neurons, which are mostly noted regarding to the drug addictive conditions of the brain, correspond to the type IV - multipolar neurons. Results. Two regions of human nucleus accumbens could be clearly recognized on Nissl and Golgi preparations each containing different predominant neuronal types. Central part of nucleus accumbens, core region, has a low density of impregnated neurons with predominant type III, pyramidal-like neurons, with spines on secondary branches and rare type IV, multipolar neurons. Contrary to the core, peripheral region, shell of nucleus, has a high density of impregnated neurons predominantly contained of type I and type IV - multipolar neurons, which all are rich in spines on secondary and tertiary dendritic branches. Conclusion. Our results indicate great morphological variability of human nucleus accumbens neurons. This requires further investigations and clarifying clinical significance of this important brain region.

  16. Formation of light particles in nucleus-nucleus collisions

    International Nuclear Information System (INIS)

    The principal experimental results on the yield of the light charged particles in nucleus-nucleus collisions at the low and intermediate energies are reviewed. Inclusive spectra of light particles and their coincidences with the characteristic KX-rays, γ-rays, neutrons, projectile-like fragments, other light particles, fission fragments, and evaporation residues are analyzed. The main theoretical models used for the description of the light particle formation are briefly outlined together with their merits and shortcomings. The unsolved problems of fast light particle formation, in particular, and of nucleus-nucleus interaction dynamics, on the whole, are discussed with the outlooks of new experiments able to clear up some of these problems. (author) 144 refs., 40 figs., 2 tabs

  17. Exotic atoms and the kaon-nucleon interaction

    International Nuclear Information System (INIS)

    Recent progress in the study of p-bar-p and p-bar-nucleus atoms is briefly reviewed before moving on to a discussion of the kaon-nucleon interaction at low energies. The need for new definitive X-ray measurements for K-p atoms is emphasised. Finally some comments are made about K-bar-nucleus and Σ-, Ξ- and Ω- atoms. (author)

  18. Strong Interactions in Strange Exotic Atoms

    Science.gov (United States)

    Mareš, J.

    2003-08-01

    Strong interaction level shifts and widths in - and K- atoms have been analyzed. The phenomenological density dependent approach as well as the relativistic mean field (RMF) model yield nucleus optical potentials with a repulsive real part in the nuclear interior. This has important consequences for the spectroscopy of hypernuclei. The study of K- atoms cannot resolve the depth of the K- nucleus potential. The fits to the kaonic atom data are satisfactory for both the relatively shallow potentials derived from chiral models and for the deep potentials based on the phenomenological and RMF analyses.

  19. Pion degrees of freedom in nucleus-nucleus collisions

    Energy Technology Data Exchange (ETDEWEB)

    Voskresenskii, D.N.; Senatorov, A.V.

    1988-07-01

    Within the framework of the theory of finite Fermi systems with the pion degree of freedom singled out explicitly we have discovered a number of qualitative effects which must be taken into account in calculations of the equation of state of heated dense nuclear matter. These effects are simulated in a calculation of the main characteristics of nucleus-nucleus collisions. The regularities found are in agreement with experimental indications, which confirms the idea of softness of the pion mode in dense heated nuclear matter.

  20. Dynamical nucleus-nucleus potential at short distances

    OpenAIRE

    Jiang, Yongying; Wang, Ning; Li, Zhuxia; Scheid, Werner

    2010-01-01

    The dynamical nucleus-nucleus potentials for fusion reactions 40Ca+40Ca, 48Ca+208Pb and 126Sn+130Te are studied with the improved quantum molecular dynamics (ImQMD) model together with the extended Thomas-Fermi approximation for the kinetic energies of nuclei. The obtained fusion barrier for 40Ca+40Ca is in good agreement with the extracted fusion barrier from the measured fusion excitation function, and the depth of the fusion pockets are close to the results of time-dependent Hartree-Fock c...

  1. Selected Experimental Highlights from Nucleus-Nucleus Collisions at RHIC

    CERN Document Server

    Huang, H Z

    2006-01-01

    Nucleus-nucleus collisions at RHIC produce high temperature and high energy density matter which exhibits partonic degrees of freedom. We will discuss measurements of nuclear modification factors for light hadrons and non-photonic electrons from heavy quark decays, which reflect the flavor dependence of energy loss of high momentum partons traversing the dense QCD medium. The hadronization of bulk partonic matter exhibits collectivity in effective partonic degrees of freedom. Nuclear collisions at RHIC provide an intriguing environment, where many constituent quark ingredients are readily available for possible formation of exotic particles through quark coalescences or recombinations.

  2. Wave Function of the Dirac Equation for an Electron in the Field of a Nucleus Expressed in Terms of an Eigenfunction of the Spin Projection Operator and a Wave Function of the Schrödinger Equation. Radiative Processes of a Hydrogen-Like Atom and Selection Rules

    Science.gov (United States)

    Skobelev, V. V.

    2016-05-01

    A solution of the Dirac equation for an electron in the field of a point nucleus (Ze), expressed in terms of an eigenfunction of the operator of the spin projection onto the third axis and the corresponding solution of the Schrödinger equation is derived. This solution is suitable for practical calculations. On the basis of this solution, using ordinary methods of QED and field theory, general principles for the emission of photons, axions, and neutrinos {(Ze)}^{*}to (Ze)+γ, a, voverline{v} by a hydrogen-like atom are formulated which take into account the spin state of the electron and, in the case of photons, their polarization. This range of questions pertaining to a comparative characteristic of processes of emission of massless or almost massless particles has, to this day, not been discussed from this point of view in the literature. Selection rules for γ, a,voverline{v} emission processes are also obtained, where for axions and neutrinos they coincide with the existing selection rules in the literature ∆m = 0,±1; with ∆l = ±1 pertaining to photons, but for photon emission a few of them do in fact differ from them with the hypothesis of odd values of ∆l, not established by us and additional to the usual values ∆l = ±1 of variation of the azimuthal quantum number l due to the appearance of "new" integrals over the spherical angle θ for ∆m = ±1, where for ∆m = 0, as before, ∆l = ±1. Moreover, the dependence of the amplitude of the photon emission process on the quantum numbers is in principle different than in the previously adopted approach to the problem although the lifetime in the excited state for small values of the quantum numbers coincides in order of magnitude with the accepted value 10-9 s.

  3. Observation of relativistic antihydrogen atoms

    Science.gov (United States)

    Blanford, Glenn Delfosse, Jr.

    1997-09-01

    An observation of relativistic antihydrogen atoms is reported in this dissertation. Experiment 862 at Fermi National Accelerator Laboratory observed antihydrogen atoms produced by the interaction of a circulating beam of high momentum (3 production is outlined within. The cross section corresponds to the process where a high momentum antiproton causes e+e/sp- pair creation near a nucleus with the e+ being captured by the antiproton. Antihydrogen is the first atom made exclusively of antimatter to be detected. The observation experiment's results are the first step towards an antihydrogen spectroscopy experiment which would measure the n = 2 Lamb shift and fine structure.

  4. 11. 208 82Pb, 232 90 Th, 256 100 Fm nucleus internal structure and Parameter calculation

    Directory of Open Access Journals (Sweden)

    Huang Zhenqiang and Huang Yuxiang

    2013-10-01

    Full Text Available Pass in front of the internal structure of the nucleus, chapter 7 ~ 10 nuclear force, magnetic forming principle and parameters of calculation, we not only have "assembly" the basis of atomic nuclei, and predictable "assembly" nucleus must abide by the principle of a couple of items. At the same time also will to book model, theory of thorough and the strict proof of simulatio

  5. Heavy-ion nucleus scattering

    CERN Document Server

    Rahman, M A; Haque, S

    2003-01-01

    Heavy ion-nucleus scattering is an excellent laboratory to probe high spin phenomena, exotic nuclei and for the analysis of various exit channels. The Strong Absorption Model or the generalized diffraction models, which are semi-classical in nature, have been employed in the description of various heavy ion-nucleus scattering phenomena with reasonable success. But one needs to treat the deflection function (scattering angles) quantum mechanically in the Wave Mechanical picture for the appropriate description of the heavy-ion nucleus scattering phenomena. We have brought the mathematics for the cross-section of the heavy-ion nucleus scattering to an analytic expression taking account of the deflection function (scattering angles) quantum mechanically. sup 9 Be, sup 1 sup 6 O, sup 2 sup 0 Ne and sup 3 sup 2 S heavy-ion beams elastic scattering from sup 2 sup 8 Si, sup 2 sup 4 Mg and sup 4 sup 0 Ca target nuclei at various projectile energies over the range 20-151 MeV have been analysed in terms of the 2-paramet...

  6. Machines géantes pour sonder l'univers de l'atome

    CERN Multimedia

    Wilde, M, S

    1966-01-01

    To always more deeply explore the infinitely small world of the atom, Science is paradoxically brought to build buildings and machines increasingly larger - Giant accelerators producing high energy particle beams that can dissociate the structures of the atomic nucleus

  7. Transverse Energy in nucleus-nucleus collisions: A review

    Energy Technology Data Exchange (ETDEWEB)

    Tincknell, M.

    1988-11-15

    The status of Transverse Energy (E/sub T/) in relativistic nucleus-nucleus collisions at the Brookhaven AGS and the CERN SPS is reviewed. The definition of E/sub T/ and its physical significance are discussed. The basic techniques and limitations of the experimental measurements are presented. The acceptances of the major experiments to be discussed are shown, along with remarks about their idiosyncrasies. The data demonstrate that the nuclear geometry of colliding spheres primarily determines the shapes of the observed spectra. Careful account of the acceptances is crucial to comparing and interpreting results. It is concluded that nuclear stopping power is high, and that the amount of energy deposited into the interaction volume is increasing with beam energy even at SPS energies. The energy densities believed to be obtained at the SPS are close to the critical values predicted for the onset of a quark-gluon plasma. 25 refs., 8 figs.

  8. Azimuthal correlation and collective behavior in nucleus-nucleus collisions

    Energy Technology Data Exchange (ETDEWEB)

    Mali, P.; Mukhopadhyay, A., E-mail: amitabha-62@rediffmail.com; Sarkar, S. [University of North Bengal, Department of Physics (India); Singh, G. [SUNY at Fredonia, Department of Computer and Information Science (United States)

    2015-03-15

    Various flow effects of nuclear and hadronic origin are investigated in nucleus-nucleus collisions. Nuclear emulsion data collected from {sup 84}Kr + Ag/Br interaction at an incident energy of 1.52 GeV per nucleon and from {sup 28}Si + Ag/Br interaction at an incident energy of 14.5 GeV per nucleon are used in the investigation. The transverse momentum distribution and the flow angle analysis show that collective behavior, like a bounce-off effect of the projectile spectators and a sidesplash effect of the target spectators, are present in our event samples. From an azimuthal angle analysis of the data we also see a direct flow of the projectile fragments and of the produced charged particles. On the other hand, for both data samples the target fragments exhibit a reverse flow, while the projectile fragments exhibit an elliptic flow. Relevant flow parameters are measured.

  9. Azimuthal correlation and collective behavior in nucleus-nucleus collisions

    International Nuclear Information System (INIS)

    Various flow effects of nuclear and hadronic origin are investigated in nucleus-nucleus collisions. Nuclear emulsion data collected from 84Kr + Ag/Br interaction at an incident energy of 1.52 GeV per nucleon and from 28Si + Ag/Br interaction at an incident energy of 14.5 GeV per nucleon are used in the investigation. The transverse momentum distribution and the flow angle analysis show that collective behavior, like a bounce-off effect of the projectile spectators and a sidesplash effect of the target spectators, are present in our event samples. From an azimuthal angle analysis of the data we also see a direct flow of the projectile fragments and of the produced charged particles. On the other hand, for both data samples the target fragments exhibit a reverse flow, while the projectile fragments exhibit an elliptic flow. Relevant flow parameters are measured

  10. Nucleus--nucleus interactions in the inner crust of neutron stars

    CERN Document Server

    Kobyakov, D

    2016-01-01

    The interaction between nuclei in the inner crust of neutron stars consists of two contributions, the so-called "direct" interaction and an "induced" one due to density changes in the neutron fluid. For large nuclear separations $r$ the contributions from nuclear forces to each of these terms are shown to be nonzero. In the static limit they are equal in magnitude but have opposite signs and they cancel exactly. We analyze earlier results on effective interactions in the light of this finding. We consider the properties of long-wavelength collective modes and, in particular, calculate the degree of mixing between the lattice phonons and the phonons in the neutron superfluid. Using microscopic theory, we calculate the net non-Coulombic contribution to the nucleus--nucleus interaction and show that, for large $r$, the leading term is due to exchange of two phonons and varies as $1/r^7$: it is an analog of the Casimir--Polder interaction between neutral atoms.

  11. Atom Chips

    CERN Document Server

    Folman, R; Cassettari, D; Hessmo, B; Maier, T; Schmiedmayer, J; Folman, Ron; Krüger, Peter; Cassettari, Donatella; Hessmo, Björn; Maier, Thomas

    1999-01-01

    Atoms can be trapped and guided using nano-fabricated wires on surfaces, achieving the scales required by quantum information proposals. These Atom Chips form the basis for robust and widespread applications of cold atoms ranging from atom optics to fundamental questions in mesoscopic physics, and possibly quantum information systems.

  12. Pion production at 1800 in nucleus-nucleus collisions

    International Nuclear Information System (INIS)

    A survey experiment of pion production at 1800 in nucleus-nucleus collisions is presented. Beams of 1.05 GeV/A and 2.1 GeV/A protons, alphas, and carbon were used, as well as proton beams of 0.80 GeV, 3.5 GeV, and 4.89 GeV, and argon beams of 1.05 GeV/A and 1.83 GeV/A. This is the first such experiment to use the heavier beams. Targets used ranged from carbon to lead. An in-depth review of the literature, both experimental and theoretical, is also presented. The systematics of the data are discussed, and comparisons are made both with prior experiments and with the predictions of the models reviewed. The cross sections appear consistent with a simple single nucleon-nucleon collision picture, without the need for collective or other exotic effects. Suggestions for future work are made

  13. Applying the elastic model for various nucleus-nucleus fusion

    International Nuclear Information System (INIS)

    The Elastic Model of two free parameters m,d given by Scalia has been used for wider energy regions to fit the available experimental data for potential barriers and cross sections. In order to generalize Scalia's formula in both sub- and above-barrier regions, we calculated m, d for pairs rather than those given by Scalia and compared the calculated cross sections with the experimental data. This makes a generalization of the Elastic Model in describing fusion process. On the other hand, Scalia's range of interacting systems was 24 ≤ A ≤194 where A is the compound nucleus mass number. Our extension of that model includes an example of the pairs of A larger than his final limit aiming to make it as a general formula for any type of reactants: light, intermediate or heavy systems. A significant point is the comparison of Elastic Model calculations with the well known methods studying complete fusion and compound nucleus formation, namely with the resultants of using Proximity potential with either Sharp or Smooth cut-off approximations

  14. Resonances in -light nucleus systems

    Indian Academy of Sciences (India)

    K P Khemchandani; N G Kelkar; M Nowakowski; B K Jain

    2006-04-01

    We locate resonances in -light nucleus elastic scattering using the time delay method. We solve few-body equations within the finite rank approximation in order to calculate the -matrices and hence the time delay for the - 3He and - 4He systems. We find a resonance very close to the threshold in - 3 He elastic scattering, at about 0.5 MeV above threshold with a width of ∼ 2 MeV. The calculations also hint at the presence of sub-threshold states in both the cases.

  15. Turbulent mixing condensation nucleus counter

    Science.gov (United States)

    Mavliev, Rashid

    The construction and operating principles of the Turbulent Mixing Condensation Nucleus Counter (TM CNC) are described. Estimations based on the semiempirical theory of turbulent jets and the classical theory of nucleation and growth show the possibility of detecting particles as small as 2.5 nm without the interference of homogeneous nucleation. This conclusion was confirmed experimentally during the International Workshop on Intercomparison of Condensation Nuclei and Aerosol Particle Counters (Vienna, Austria). Number concentration, measured by the Turbulent Mixing CNC and other participating instruments, is found to be essentially equal.

  16. About possibility to search the electron EDM at the level $10^{-28} \\div 10^{-30}$ e$\\cdot$cm and the constant of T-odd, P-odd scalar weak interaction of an electron with a nucleus at the level $10^{-5} \\div 10^{-7}$ in the heavy atoms and ferroelectrics

    OpenAIRE

    Baryshevsky, V. G.

    2005-01-01

    The T-odd phenomenon of induction of the magnetic field by a static electric field provides to study the electron EDM and constants of T-odd, P-odd interaction of an electron with a nucleus. Measurement of this magnetic field for ferroelectric materials (like PbTiO_3) at the level B~3 10^{-18} G allows to derive the electric dipole moment of an electron at the level d_e ~ 10^{-30} e cm and the constant of T-odd scalar weak interaction of an electron with a nucleus at the level k_1^{nuc}10^{-9...

  17. New results on nuclear multifragmentation in nucleon-nucleus and nucleus-nucleus collisions at relativistic energies

    International Nuclear Information System (INIS)

    Some new aspects on the multifragmentation processes in nucleus-nucleus and nucleon-nucleus collisions at high energies are discussed in this work. Experimental data obtained in international collaborations (for example, MULTI Collaboration with KEK Tsukuba (Japan) and SKM 200 Collaboration with JINR Dubna (Russia)) are used to discuss new mechanisms in the target nucleus fragmentation. Correlations with stopping power, participant region size and energy density are included. Comparisons of the experimental results with the predictions of a phenomenological geometric model of intermediate mass fragment multiplicity, caloric curves and angular distributions are also presented. These results are used for global description of the multifragmentation processes in nucleon-nucleus and nucleus-nucleus collisions at relativistic energies. The size of the participant region and the average intermediate mass fragments multiplicity are taken into consideration using the free space probability. A few correlations between the deposited energy in the participant region and stability state of the intermediate mass fragments are presented in this work. The importance of the collision geometry in the multifragmentation processes is stressed. The results suggest different time moments for the incident nucleus fragmentation and for the target nucleus fragmentation. The associated entropies are distinct. (authors)

  18. Atom chips

    CERN Document Server

    Reichel, Jakob

    2010-01-01

    This book provides a stimulating and multifaceted picture of a rapidly developing field. The first part reviews fundamentals of atom chip research in tutorial style, while subsequent parts focus on the topics of atom-surface interaction, coherence on atom chips, and possible future directions of atom chip research. The articles are written by leading researchers in the field in their characteristic and individual styles.

  19. Determination of Coil Inductances Cylindrical Iron Nucleus

    Directory of Open Access Journals (Sweden)

    Azeddine Mazouz

    2014-03-01

    Full Text Available The paper describes the investigation and development of a structure and performance characteristics of a coil iron nucleus cylindrical (C.I.N.C. The coil iron nucleus cylindrical is a nonlinear electro radio in which the moving of the nucleus in a sense or in other causes change in inductance and can reach extreme values at the superposition of nucleus and coil centers. The variation of the inductance and the degree of freedom of movement of the nucleus can lead to a device with electromechanical conversion The aim of this paper is the determination and visualization of self inductance and mutual of the (C.I.N.C based on geometric dimensions and the displacement of the nucleus.  

  20. An organism arises from every nucleus.

    OpenAIRE

    Nurullah Keklikoglu

    2009-01-01

    The fact that, cloning using somatic cell nuclear transfer (SCNT) method has been performed, opened new horizons for cloning, and changed the way of our understanding and approach to cell and nucleus. The progress in cloning technology, brought the anticipation of the ability to clone an organism from each somatic cell nucleus. Therefore, the 'Cell Theory' is about to take the additional statement as "An organism arises from every nucleus". The development of gene targeting procedures which c...

  1. Atomic Physics

    CERN Document Server

    Foot, Christopher J

    2007-01-01

    This text will thoroughly update the existing literature on atomic physics. Intended to accompany an advanced undergraduate course in atomic physics, the book will lead the students up to the latest advances and the applications to Bose-Einstein Condensation of atoms, matter-wave inter-ferometry and quantum computing with trapped ions. The elementary atomic physics covered in the early chapters should be accessible to undergraduates when they are first introduced to the subject. To complement. the usual quantum mechanical treatment of atomic structure the book strongly emphasizes the experimen

  2. The Atomic Fingerprint: Neutron Activation Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Keisch, Bernard [Carnegie-Mellon University

    1972-01-01

    The nuclei of atoms are stable only when they contain certain numbers of neutrons and protons. Since nuclei can absorb additional neutrons, which in many cases results in the conversion of a stable nucleus to a radioactive one, neutron activation analysis is possible.

  3. Atom interferometry

    International Nuclear Information System (INIS)

    We will first present a development of the fundamental principles of atom interferometers. Next we will discuss a few of the various methods now available to split and recombine atomic De Broglie waves, with special emphasis on atom interferometers based on optical pulses. We will also be particularly concerned with high precision interferometers with long measurement times such those made with atomic fountains. The application of atom interferometry to the measurement of the acceleration due to gravity will be detailed. We will also develop the atom interferometry based on adiabatic transfer and we will apply it to the measurement of the photon recoil in the case of the Doppler shift of an atomic resonance caused by the momentum recoil from an absorbed photon. Finally the outlook of future developments will be given. (A.C.)

  4. Integrated Azimuthal Correlations in Nucleus-Nucleus Collisions at CERN SPS

    OpenAIRE

    Grebieszkow, Katarzyna; Mrowczynski, Stanislaw

    2011-01-01

    Azimuthal correlations of particles produced in nucleus-nucleus collisions at CERN SPS are discussed. The correlations quantified by the integral measure Phi are shown to be dominated by effects of collective flow.

  5. Physical meaning of the yields from hadron-nucleon, hadron-nucleus, and nucleus-nucleus collisions observed in experiments

    International Nuclear Information System (INIS)

    A physical meaning of the outcomes from hadronic and nuclear collision processes at high energies is presented, as prompted experimentally. The fast and slow stages in hadron-nucleus collisions are distinguished. Hadrons are produced via intermediate objects observed in hadron-nucleus collisions. The intermediate objects may be treated as the groups of quarks or the quark bags. 37 refs

  6. Intrinsic electric dipole moments of paramagnetic atoms : Rubidium and cesium

    NARCIS (Netherlands)

    Nataraj, H. S.; Sahoo, B. K.; Das, B. P.; Mukherjee, D.

    2008-01-01

    The electric dipole moment (EDM) of paramagnetic atoms is sensitive to the intrinsic EDM contribution from that of its constituent electrons and a scalar-pseudoscalar (S-PS) electron-nucleus interaction. The electron EDM and the S-PS contributions to the EDMs of these atoms scale as approximate to Z

  7. Nucleus accumbens receives gastric vagal inputs

    Institute of Scientific and Technical Information of China (English)

    Sangeeta MEHENDALE; Jing-tian XIE; Han H AUNG; Xiong-Fei GUAN; Chun-Su YUAN

    2004-01-01

    AIM: To localize and characterize the response of single accumbal neurons to electrical stimulation of the gastric vagal fibers. METHODS: Unitary responses to electrical stimulation of the ventral and dorsal gastric vagal fibers which serve the proximal stomach were recorded extracellularly in the nucleus accumbens in anesthetized cats.RESULTS: The evoked units recorded in the nucleus accumbens consisted of phasic and tonic responses, with a mean latency of (396±43) ms. Convergence of ventral and dorsal gastric vagal inputs onto single phasic and tonic accumbal units was observed. For tonic inhibitory responses, convergence was exhibited when stimulation applied to both the ventral and dorsal gastric vagal branches resulted in a significantly longer inhibitory period than did stimulation of a single gastric vagal branch. Comparing the gastric vagally evoked accumbal unitary responses to the neuronal responses recorded in the nucleus tractus solitarius, parabrachial nucleus and hypothalamus in our previous studies, our data showed a higher percentage of single spike responses and shorter response duration's in the nucleus accumbens than in the other nuclei. This suggests that the synaptic drive from the gastric vagal inputs to the nucleus accumbens is less powerful than in the other structures. CONCLUSION: The present study localized and characterized gastric vagally evoked responses in the nucleus accumbens, which suggest that the nucleus accumbens may process gastric signals concerned with the ingestive process.

  8. Angular characteristics of pion-nucleus interaction

    International Nuclear Information System (INIS)

    In the present paper pion-nucleus interactions have been studied using nuclear emulsion technique. The investigation of these interactions is expected to provide some very useful information about the multiparticle production mechanism. Nuclear emulsion is a material which memorizes the tracks of charged particles. When a primary particle collides with a nucleus, it may interact with the nucleons of the target nucleus in two ways. In the first case, independent reactions may take place between the incident particle and the nucleons present in the target nucleus. Secondly the primary particle may interact coherently with the various nucleons of the target nucleus and the secondary particles are produced. Angular distribution of charged secondaries produced in these interactions has been studied for central collision events. Different workers have used different criterion for the selection of central collisions. We analysed the events with high shower particle multiplicity i.e., Ns ≥ 28 and call them as central collision events

  9. Atomic physics

    International Nuclear Information System (INIS)

    Research activities in atomic physics at Lawrence Berkeley Laboratory during 1976 are described. Topics covered include: experiments on stored ions; test for parity violation in neutral weak currents; energy conservation and astrophysics; atomic absorption spectroscopy, atomic and molecular detectors; theoretical studies of quantum electrodynamics and high-z ions; atomic beam magnetic resonance; radiative decay from the 23Po,2 levels of helium-like argon; quenching of the metastable 2S/sub 1/2/ state of hydrogen-like argon in an external electric field; and lifetime of the 23Po level of helium-like krypton

  10. The retrotrapezoid nucleus and breathing.

    Science.gov (United States)

    Guyenet, Patrice G; Stornetta, Ruth L; Abbott, Stephen B G; Depuy, Seth D; Kanbar, Roy

    2012-01-01

    The retrotrapezoid nucleus (RTN) is located in the rostral medulla oblongata close to the ventral surface and consists of a bilateral cluster of glutamatergic neurons that are non-aminergic and express homeodomain transcription factor Phox2b throughout life. These neurons respond vigorously to increases in local pCO(2) via cell-autonomous and paracrine (glial) mechanisms and receive additional chemosensory information from the carotid bodies. RTN neurons exclusively innervate the regions of the brainstem that contain the respiratory pattern generator (RPG). Lesion or inhibition of RTN neurons largely attenuates the respiratory chemoreflex of adult rats whereas their activation increases respiratory rate, inspiratory amplitude and active expiration. Phox2b mutations that cause congenital central hypoventilation syndrome in humans prevent the development of RTN neurons in mice. Selective deletion of the RTN Phox2b-VGLUT2 neurons by genetic means in mice eliminates the respiratory chemoreflex in neonates.In short, RTN Phox2b-VGLUT2 neurons are a major nodal point of the CNS network that regulates pCO(2) via breathing and these cells are probable central chemoreceptors. PMID:23080151

  11. Music and the nucleus accumbens.

    Science.gov (United States)

    Mavridis, Ioannis N

    2015-03-01

    Music is a universal feature of human societies over time, mainly because it allows expression and regulation of strong emotions, thus influencing moods and evoking pleasure. The nucleus accumbens (NA), the most important pleasure center of the human brain (dominates the reward system), is the 'king of neurosciences' and dopamine (DA) can be rightfully considered as its 'crown' due to the fundamental role that this neurotransmitter plays in the brain's reward system. Purpose of this article was to review the existing literature regarding the relation between music and the NA. Studies have shown that reward value for music can be coded by activity levels in the NA, whose functional connectivity with auditory and frontal areas increases as a function of increasing musical reward. Listening to music strongly modulates activity in a network of mesolimbic structures involved in reward processing including the NA. The functional connectivity between brain regions mediating reward, autonomic and cognitive processing provides insight into understanding why listening to music is one of the most rewarding and pleasurable human experiences. Musical stimuli can significantly increase extracellular DA levels in the NA. NA DA and serotonin were found significantly higher in animals exposed to music. Finally, passive listening to unfamiliar although liked music showed activations in the NA. PMID:25102783

  12. Atomic physics

    CERN Document Server

    Born, Max

    1989-01-01

    The Nobel Laureate's brilliant exposition of the kinetic theory of gases, elementary particles, the nuclear atom, wave-corpuscles, atomic structure and spectral lines, electron spin and Pauli's principle, quantum statistics, molecular structure and nuclear physics. Over 40 appendices, a bibliography, numerous figures and graphs.

  13. Analysis of Subthreshold Antiproton Production in p-Nucleus and Nucleus-Nucleus Collisions in the RBUU Approach

    CERN Document Server

    Teis, S; Maruyama, T; Mosel, U; Teis, Stefan; Cassing, Wolfgang; Maruyama, Tomoyuki; Mosel, Ulrich

    1994-01-01

    We calculate the subthreshold production of antiprotons in the Lorentz-covariant RBUU approach employing a weighted testparticle method to treat the antiproton propagation and absorption nonperturbatively. We find that the pbar differential cross sections are highly sensitive to the baryon and antiproton selfenergies in the dense baryonic environment. Adopting the baryon scalar and vector selfenergies from the empirical optical potential for proton-nucleus elastic scattering and from Dirac-Brueckner calculations at higher density rho > rho_0 we examine the differential pbar spectra as a function of the antiproton selfenergy. A detailed comparison with the available experimental data for p-nucleus and nucleus-nucleus reactions shows that the antiproton feels a moderately attractive mean-field at normal nuclear matter density rho_0 which is in line with a dispersive potential extracted from the free annihilation cross section.

  14. Nucleus accumbens stimulation in pathological obesity.

    Science.gov (United States)

    Harat, Marek; Rudaś, Marcin; Zieliński, Piotr; Birska, Julita; Sokal, Paweł

    2016-01-01

    One of the potential treatment methods of obesity is deep brain stimulation (DBS) of nucleus accumbens. We describe the case of 19 years old woman with hypothalamic obesity. She weighted 151.4 kg before DBS and the non-surgical methods proved to be inefficient. She was treated with implantation of DBS electrode to nucleus accumbens bilaterally. Results were measured with body mass index and neuropsychological tests. Follow-up was 14 months. Fourteen months after surgery weight was 138 kg, BMI was 48.3. Neuropsychological test results were intact. The presented case supports the thesis of treatment of obesity with nucleus accumbens stimulation. PMID:27154450

  15. Study of Hadron Production in Hadron-Nucleus and Nucleus-Nucleus Collisions at the CERN SPS

    CERN Multimedia

    Selyuzhenkov, I; Kowalski, S; Kaptur, E A; Kowalik, K L; Dominik, W M; Krasnoperov, A; Feofilov, G; Vinogradov, L; Kovalenko, V; Johnson, S R; Mills, G B; Planeta, R J; Rubbia, A; Robert, A L; Marton, K; Messerly, B A; Puzovic, J; Bogomilov, M V; Bravar, A; Sgalaberna, D; Renfordt, R A E; Deveaux, M; Engel, R R; Grzeszczuk, A; Davis, N; Kuich, M; Lyubushkin, V; Igolkin, S; Kondratev, V; Kadija, K; Diakonos, F; Slodkowski, M A; Rauch, W H; Pistillo, C; Laszlo, A; Nakadaira, T; Hasegawa, T; Zambelli, L A; Sadovskiy, A; Morozov, S; Petukhov, O; Szuba, M K; Mathes, H; Herve, A E; Roehrich, D; Marino, A D; Wyszynski, O J; Grebieszkow, K; Di luise, S; Wlodarczyk, Z; Rybczynski, M A; Wojtaszek-szwarc, A; Nirkko, M C; Sakashita, K; Golubeva, M; Kurepin, A; Manic, D; Kolev, D I; Kisiel, J E; Rondio, E; Czopowicz, T R; Seyboth, P; Turko, L; Guber, F; Marin, V; Busygina, O; Taranenko, A; Cirkovic, M; Gazdzicki, M; Roth, M A; Pulawski, S M; Aduszkiewicz, A M; Bunyatov, S; Vechernin, V; Nagai, Y; Anticic, T; Larsen, D T; Dynowski, K M; Mackowiak-pawlowska, M K; Stefanek, G; Pavin, M; Fodor, Z P; Nishikawa, K; Tada, M; Kobayashi, T; Blondel, A P P; Hasler, A; Damyanova, A; Stroebele, H W; Rustamov, A; Klochkov, V; Posiadala, M Z; Kolesnikov, V; Andronov, E; Zimmerman, E D; Antoniou, N; Majka, Z; Veberic, D; Dumarchez, J; Naskret, M; Ivashkin, A; Tsenov, R V; Koziel, M G; Schmidt, K J; Melkumov, G; Popov, B; Panagiotou, A; Richter-was, E M; Ereditato, A; Paolone, V; Korzenev, A; Unger, M T; Wilczek, A G; Stepaniak, J M; Matulewicz, T N; Seryakov, A; Susa, T; Staszel, P P; Marcinek, A J; Brzychczyk, J; Maksiak, B; Tefelski, D B

    2007-01-01

    The NA61/SHINE (SHINE = SPS Heavy Ion and Neutrino Experiment) experiment is a large acceptance hadron spectrometer at the CERN SPS for the study of the hadronic final states produced in interactions of various beam particles (pions, protons, C, S and In) with a variety of fixed targets at the SPS energies. The main components of the current detector were constructed and used by the NA49 experiment. The physics program of NA61/SHINE consists of three main subjects. In the first stage of data taking (2007-2009) measurements of hadron production in hadron-nucleus interactions needed for neutrino (T2K) and cosmic-ray (Pierre Auger and KASCADE) experiments will be performed. In the second stage (2009-2011) hadron production in proton-proton and proton-nucleus interactions needed as reference data for a better understanding of nucleus-nucleus reactions will be studied. In the third stage (2009-2013) energy dependence of hadron production properties will be measured in nucleus-nucleus collisions as well as in p+p a...

  16. Parabrachial nucleus involvement in multiple system atrophy☆

    OpenAIRE

    Benarroch, E.E.; Schmeichel, A.M.; Low, P. A.; Parisi, J.E.

    2013-01-01

    Multiple system atrophy (MSA) is associated with respiratory dysfunction, including sleep apnea, respiratory dysrhythmia, and laryngeal stridor. Neurons of the parabrachial nucleus (PBN) control respiratory rhythmogenesis and airway resistance.

  17. The nucleus in Finland - The second report

    International Nuclear Information System (INIS)

    The Finnish Nuclear Society (FNS) started the distribution of the Nucleus bulletin at the beginning of 1988. The volume of distribution has been extended since, including today nearly 1,000 persons. Both the English and the Finnish version of the bulletin is sent to various opinion leaders of society, i.e. the members of the parliament, ministries, the media, representatives of industry and other decision-makers of the energy field. After the five-year history of the Nucleus in Finland, it is time to look back and sum up the present status of the Nucleus. This report gives a short summary concerning the present distribution and its efficiency, the experiences gained and the influence of the bulletin in Finland. The first questionnaire was sent in November 1988, and the survey was repeated among the Finnish readers of the Nucleus in autumn 1992. The results of the latter survey are given in this report

  18. Testing string dynamics in lepton nucleus reactions

    International Nuclear Information System (INIS)

    The sensitivity of nuclear attenuation of 10-100 GeV lepton nucleus (ell A) reactions to space-time aspects of hadronization is investigated within the context of the Lund string model. We consider two mechanisms for attenuation in a nucleus: final state cascading and string flip excitations. Implications for the evolution of the energy density in nuclear collisions are discussed. 16 refs., 10 figs

  19. Search for monopole excitation of nucleus in the bound muon decay

    International Nuclear Information System (INIS)

    The aim of the paper is the theoretical and experimantal foundation of investigation of nucleus excitation in the bound muon decay. Two other types of nucleus excitation in muon atoms are well known: excitation in muon cascade transitions and as a result of μ-capture. The energy, being considerably higher the energy of low-lying nuclear excitations, is related in μ-decay. The potential affecting from the side of the bound muon on the nucleus is practically turned off at once, that causes quantum transitions in the nucleus. Characteristics of nuclear O+ states and probabilities of their excitation in the bound muon decay for some nuclei of the Ca-Pu region are presented. The foundation for the experiment of searching for the phenomenon investigated is the registration of electron coincidence in μ-decay with γ-quanta of nuclear transitions. The 152Sn nucleus is chosen as a target. The experimental data obtained give the possibility to establish the upper limit of probability of the first O+ level excitation of 152Sm in the bound muon decay: w -3. It does not confirm the correctness of the experimental results given and closes the earlier estimation of probability w ∼ 1.6x10-2

  20. Atomic secrecy

    International Nuclear Information System (INIS)

    An article, The H-Bomb Secret: How We Got It, Why We're Telling It, by Howard Morland was to be published in The Progressive magazine in February, 1979. The government, after learning of the author's and the editors' intention to publish the article and failing to persuade them to voluntarily delete about 20% of the text and all of the diagrams showing how an H-bomb works, requested a court injunction against publication. Acting under the Atomic Energy Act of 1954, US District Court Judge Robert W. Warren granted the government's request on March 26. Events dealing with the case are discussed in this publication. Section 1, Progressive Hydrogen Bomb Case, is discussed under the following: Court Order Blocking Magazine Report; Origins of the Howard Morland Article; Author's Motives, Defense of Publication; and Government Arguments Against Disclosure. Section 2, Access to Atomic Data Since 1939, contains information on need for secrecy during World War II; 1946 Atomic Energy Act and its effects; Soviet A-Bomb and the US H-Bomb; and consequences of 1954 Atomic Energy Act. Section 3, Disputed Need for Atomic Secrecy, contains papers entitled: Lack of Studies on H-Bomb Proliferation; Administration's Position on H-Bombs; and National Security Needs vs Free Press

  1. Computer Simulation of Atoms Nuclei Structure Using Information Coefficients of Proportionality

    CERN Document Server

    Labushev, Mikhail M

    2012-01-01

    The latest research of the proportionality of atomic weights of chemical elements made it possible to obtain 3 x 3 matrices for the calculation of information coefficients of proportionality Ip that can be used for 3D modeling of the structure of atom nucleus. The results of computer simulation show high potential of nucleus structure research for the characterization of their chemical and physical properties.

  2. Primakoff production of $\\pi^0$, $\\eta$ and $\\eta'$ in the Coulomb field of a nucleus

    OpenAIRE

    Kaskulov, Murat M.; Mosel, Ulrich

    2011-01-01

    Photoproduction of neutral pseudoscalar mesons $\\pi^0,\\eta(547)$ and $\\eta'(958)$ in the Coulomb field of an atomic nucleus is studied using a model which describes the Primakoff and nuclear parts of the production amplitude. At high energies the nuclear background is dominated by the exchange of $C$-parity odd Regge trajectories. In the coherent production the isospin filtering makes the $\\omega(782)$ a dominant trajectory. The calculations are in agreement with $\\pi^0$ data from JLAB provid...

  3. Investigation of the (232)Th Nucleus Excitations at the FEL {gamma} - Nucleus Colliders

    CERN Document Server

    Koru, H; Sultansoy, S F; Sarer, B

    2001-01-01

    The physics search potential of the FEL {gamma} - Nucleus colliders is analysed using excitations of the (232)Th nucleus. It is shown that, due to the monochromacity of FEL {gamma} beam and high statistics, proposed colliders will play an important role in the field of "traditional" nuclear physics.

  4. Observation of high energy gamma rays in intermediate energy nucleus-nucleus collisions

    NARCIS (Netherlands)

    Beard, K.B.; Benenson, W.; Bloch, C.; Kashy, E.; Stevenson, J.; Morrissey, D.J.; Plicht, J. van der; Sherrill, B.; Winfield, J.S.

    1985-01-01

    High energy electrons and positrons observed in medium energy nucleus-nucleus collisions are shown to be primarily due to the external conversion of high energy gamma rays. The reaction 14N+Cu was studied at E/A=40 MeV, and a magnetic spectrograph was used with a specially constructed multiwire prop

  5. Temperature measurement of quark-gluon plasma formed in high energy nucleus-nucleus collisions

    International Nuclear Information System (INIS)

    We discuss lepton pair and real photon emission from quark-gluon plasma, which is very likely to be formed in high energy nucleus-nucleus collisions. Measurement of pair production cross-section will provide one with accurate information of the temperature of this plasma. (author)

  6. Atomic theories

    CERN Document Server

    Loring, FH

    2014-01-01

    Summarising the most novel facts and theories which were coming into prominence at the time, particularly those which had not yet been incorporated into standard textbooks, this important work was first published in 1921. The subjects treated cover a wide range of research that was being conducted into the atom, and include Quantum Theory, the Bohr Theory, the Sommerfield extension of Bohr's work, the Octet Theory and Isotopes, as well as Ionisation Potentials and Solar Phenomena. Because much of the material of Atomic Theories lies on the boundary between experimentally verified fact and spec

  7. Influence of the electron's anomalous magnetic dipole moment on high-atomic number atoms

    International Nuclear Information System (INIS)

    Super heavy atoms ( Z > 100 ) are usually studied in the context of the so-called Quantum Electrodynamics of Strong Fields. In this theory the problem of the singularity in the electron energy whenever Z > 137 is overcome. This is done by considering the finite size of the nucleus and leads to interesting phenomena, such as the spontaneous production of positrons. Here, we show that, taking into account the contribution from the Anomalous Magnetic Dipole Moment of the electron ( by means of an effective theory ), within a point nucleus model, is a sufficient condition to obtain regular wave functions and physically acceptable energy values for Z > 137. (author)

  8. Protein quality control in the nucleus.

    Science.gov (United States)

    Jones, Ramon D; Gardner, Richard G

    2016-06-01

    The nucleus is the repository for the eukaryotic cell's genetic blueprint, which must be protected from harm to ensure survival. Multiple quality control (QC) pathways operate in the nucleus to maintain the integrity of the DNA, the fidelity of the DNA code during replication, its transcription into mRNA, and the functional structure of the proteins that are required for DNA maintenance, mRNA transcription, and other important nuclear processes. Although we understand a great deal about DNA and RNA QC mechanisms, we know far less about nuclear protein quality control (PQC) mechanisms despite that fact that many human diseases are causally linked to protein misfolding in the nucleus. In this review, we discuss what is known about nuclear PQC and we highlight new questions that have emerged from recent developments in nuclear PQC studies. PMID:27015023

  9. The nucleus: a black box being opened.

    Science.gov (United States)

    van Driel, R; Humbel, B; de Jong, L

    1991-12-01

    Until recently our knowledge about the structural and functional organization of the cell nucleus was very limited. Recent technical developments in the field of ultrastructural analysis, combined with ongoing research on the properties of the nuclear matrix, give new insight into how the nucleus is structured. Two types of observations shape our ideas about nuclear organization. First, most nuclear functions (replication, transcription, RNA processing, and RNA transport) are highly localized within the nucleus, rather than diffusely distributed. Moreover, they are associated with the nuclear matrix. Second, chromatin is organized in discrete loops, bordered by nuclear matrix attachment sequences (MARs). Each loop may contain one or several genes. The arrangement of chromatin in loops has profound consequences for the regulation of gene expression.

  10. UNCOVERING THE NUCLEUS CANDIDATE FOR NGC 253

    Energy Technology Data Exchange (ETDEWEB)

    Günthardt, G. I.; Camperi, J. A. [Observatorio Astronómico, Universidad Nacional de Córdoba (Argentina); Agüero, M. P. [Observatorio Astronómico, Universidad Nacional de Córdoba, and CONICET (Argentina); Díaz, R. J.; Gomez, P. L.; Schirmer, M. [Gemini Observatory, AURA (United States); Bosch, G., E-mail: gunth@oac.uncor.edu, E-mail: camperi@oac.uncor.edu, E-mail: mpaguero@oac.uncor.edu, E-mail: rdiaz@gemini.edu, E-mail: pgomez@gemini.edu, E-mail: mschirmer@gemini.edu, E-mail: guille@fcaglp.unlp.edu.ar [Instituto de Astrofísica de La Plata (CONICET-UNLP) (Argentina)

    2015-11-15

    NGC 253 is the nearest spiral galaxy with a nuclear starburst that becomes the best candidate for studying the relationship between starburst and active galactic nucleus activity. However, this central region is veiled by large amounts of dust, and it has been so far unclear which is the true dynamical nucleus to the point that there is no strong evidence that the galaxy harbors a supermassive black hole co-evolving with the starburst as was supposed earlier. Near-infrared (NIR) spectroscopy, especially NIR emission line analysis, could be advantageous in shedding light on the true nucleus identity. Using Flamingos-2 at Gemini South we have taken deep K-band spectra along the major axis of the central structure and through the brightest infrared source. In this work, we present evidence showing that the brightest NIR and mid-infrared source in the central region, already known as radio source TH7 and so far considered just a large stellar supercluster, in fact presents various symptoms of a genuine galactic nucleus. Therefore, it should be considered a valid nucleus candidate. Mentioning some distinctive aspects, it is the most massive compact infrared object in the central region, located at 2.″0 of the symmetry center of the galactic bar, as measured in the K-band emission. Moreover, our data indicate that this object is surrounded by a large circumnuclear stellar disk and it is also located at the rotation center of the large molecular gas disk of NGC 253. Furthermore, a kinematic residual appears in the H{sub 2} rotation curve with a sinusoidal shape consistent with an outflow centered in the candidate nucleus position. The maximum outflow velocity is located about 14 pc from TH7, which is consistent with the radius of a shell detected around the nucleus candidate, observed at 18.3 μm (Qa) and 12.8 μm ([Ne ii]) with T-ReCS. Also, the Brγ emission line profile shows a pronounced blueshift and this emission line also has the highest equivalent width at this

  11. Black Hole Atom as a Dark Matter Particle Candidate

    Directory of Open Access Journals (Sweden)

    V. I. Dokuchaev

    2014-01-01

    Full Text Available We propose the new dark matter particle candidate—the “black hole atom,” which is an atom with the charged black hole as an atomic nucleus and electrons in the bound internal quantum states. As a simplified model we consider the the central Reissner-Nordström black hole with the electric charge neutralized by the internal electrons in bound quantum states. For the external observers these objects would look like the electrically neutral Schwarzschild black holes. We suppose the prolific production of black hole atoms under specific conditions in the early universe.

  12. Black Hole Atom as a Dark Matter Particle Candidate

    International Nuclear Information System (INIS)

    We propose the new dark matter particle candidate—the “black hole atom,” which is an atom with the charged black hole as an atomic nucleus and electrons in the bound internal quantum states. As a simplified model we consider the the central Reissner-Nordström black hole with the electric charge neutralized by the internal electrons in bound quantum states. For the external observers these objects would look like the electrically neutral Schwarzschild black holes. We suppose the prolific production of black hole atoms under specific conditions in the early universe

  13. Atomic CP-violating polarizability

    International Nuclear Information System (INIS)

    Searches for CP-violating effects in atoms and molecules provide important constrains on competing extensions to the standard model of elementary particles. In particular, CP violation in an atom leads to the CP-odd (T,P-odd) polarizability βCP: a magnetic moment μCP is induced by an electric field E0 applied to an atom, μCP=βCPE0. We estimate the CP-violating polarizability for rare-gas (diamagnetic) atoms He through Rn. We relate βCP to the permanent electric dipole moment (EDM) of the electron and to the scalar constant of the CP-odd electron-nucleus interaction. The analysis is carried out using the third-order perturbation theory and the Dirac-Hartree-Fock formalism. We find that, as a function of nuclear charge Z, βCP scales steeply as Z5R(Z), where slowly varying R(Z) is a relativistic enhancement factor. Finally, we evaluate the feasibility of setting a limit on electron EDM by measuring CP-violating magnetization of liquid Xe. We find that such an experiment could provide competitive bounds on electron EDM only if the present level of experimental sensitivity to ultraweak magnetic fields [Kominis et al., Nature 422, 596 (2003)] is improved by several orders of magnitude

  14. Atomic CP-violating polarizability

    CERN Document Server

    Ravaine, B; Derevianko, A; Ravaine, Boris; Derevianko, Andrei

    2005-01-01

    Searches for CP violating effects in atoms and molecules provide important constrains on competing extensions to the standard model of elementary particles. In particular, CP violation in an atom leads to the CP-odd (T,P-odd) polarizability $\\beta^\\mathrm{CP}$: a magnetic moment $\\mu^\\mathrm{CP}$ is induced by an electric field $\\mathcal{E}_0$ applied to an atom, $\\mu^\\mathrm{CP} = \\beta^\\mathrm{CP} \\mathcal{E}_0 $. We estimate the CP-violating polarizability for rare-gas (diamagnetic) atoms He through Rn. We relate betaCP to the permanent electric dipole moment (EDM) of the electron and to the scalar constant of the CP-odd electron-nucleus interaction. The analysis is carried out using the third-order perturbation theory and the Dirac-Hartree-Fock formalism. We find that, as a function of nuclear charge Z, betaCP scales steeply as Z^5 R(Z), where slowly-varying R(Z) is a relativistic enhancement factor. Finally, we evaluate a feasibility of setting a limit on electron EDM by measuring CP-violating magnetizat...

  15. Direct projection from the suprachiasmatic nucleus to hypophysiotrophic corticotropin-releasing factor immunoreactive cells in the paraventricular nucleus of the hypothalamus demonstrated...

    DEFF Research Database (Denmark)

    Vrang, N.; Larsen, P.J.; Mikkelsen, J.D.

    1995-01-01

    Suprachiasmatic nucleus, paraventricular nucleus, circadian rhythms, phaseolus vulgaris-leucoagglutinin, corticotropin-releasing factor, dual immunocytochemistry......Suprachiasmatic nucleus, paraventricular nucleus, circadian rhythms, phaseolus vulgaris-leucoagglutinin, corticotropin-releasing factor, dual immunocytochemistry...

  16. Atomic arias

    Science.gov (United States)

    Crease, Robert P.

    2009-01-01

    The American composer John Adams uses opera to dramatize controversial current events. His 1987 work Nixon in China was about the landmark meeting in 1972 between US President Richard Nixon and Chairman Mao Zedong of China; The Death of Klinghoffer (1991) was a musical re-enactment of an incident in 1985 when Palestinian terrorists kidnapped and murdered a wheelchair-bound Jewish tourist on a cruise ship. Adams's latest opera, Doctor Atomic, is also tied to a controversial event: the first atomic-bomb test in Alamogordo, New Mexico, on 16 June 1945. The opera premièred in San Francisco in 2005, had a highly publicized debut at the Metropolitan Opera in New York in 2008, and will have another debut on 25 February - with essentially the same cast - at the English National Opera in London.

  17. Inner Structure of Boiling Nucleus and Interfacial Energy Between Nucleus and Bulk Liquid

    Institute of Scientific and Technical Information of China (English)

    WANG Xiao-Dong; TIAN Yong; PENG Xiao-Feng; WANG Bu-Xuan

    2004-01-01

    @@ A model of two-region structure of a nucleus is proposed to describe nucleus evolution. The interfacial tension between bulk liquid phase and nucleus is dependent on the density gradient in the transition region and varies with the structure change of the transition region. With the interfacial tension calculated using this model, the predicted nucleation rate is very close to the experimental measurement. Furthermore, this model and associated analysis provide solid theoretical evidence to clarify the definition of nucleation rate and understand the nucleation phenomenon with insight into the physical nature.

  18. Nucleus-Nucleus Potential at Near-Barrier Energies from Self Consistent Calculations

    CERN Document Server

    Skalski, J

    2003-01-01

    We determine the static nucleus-nucleus potential from Hartree-Fock (HF) calculations with the Skyrme interaction. To this aim, HF equations are solved on a spatial mesh, with the initial configuration consisting of target and projectile positioned at various relative distances. For a number of reaction partners, the calculated barrier heights reasonably well compare with those extracted from the measured fusion and capture cross sections. At smaller target-projectile distances, our results show the intrinsic barriers to heavy compound nucleus formation. We speculate on their possible connection with the fusion hindrance observed for large Z sub T Z sub P.

  19. Atomic physics

    Energy Technology Data Exchange (ETDEWEB)

    Livingston, A.E.; Kukla, K.; Cheng, S. [Univ. of Toledo, OH (United States)] [and others

    1995-08-01

    In a collaboration with the Atomic Physics group at Argonne and the University of Toledo, the Atomic Physics group at the University of Notre Dame is measuring the fine structure transition energies in highly-charged lithium-like and helium-like ions using beam-foil spectroscopy. Precise measurements of 2s-2p transition energies in simple (few-electron) atomic systems provide stringent tests of several classes of current atomic- structure calculations. Analyses of measurements in helium-like Ar{sup 16+} have been completed, and the results submitted for publication. A current goal is to measure the 1s2s{sup 3}S{sub 1} - 1s2p{sup 3}P{sub 0} transition wavelength in helium-like Ni{sup 26+}. Measurements of the 1s2s{sup 2}S{sub 1/2} - 1s2p{sup 2}P{sub 1/2,3/2} transition wavelengths in lithium-like Kr{sup 33+} is planned. Wavelength and lifetime measurements in copper-like U{sup 63+} are also expected to be initiated. The group is also participating in measurements of forbidden transitions in helium-like ions. A measurement of the lifetime of the 1s2s{sup 3}S{sub 1} state in Kr{sup 34+} was published recently. In a collaboration including P. Mokler of GSI, Darmstadt, measurements have been made of the spectral distribution of the 2E1 decay continuum in helium-like Kr{sup 34+}. Initial results have been reported and further measurements are planned.

  20. An organism arises from every nucleus.

    Directory of Open Access Journals (Sweden)

    Nurullah Keklikoglu

    2009-12-01

    Full Text Available The fact that, cloning using somatic cell nuclear transfer (SCNT method has been performed, opened new horizons for cloning, and changed the way of our understanding and approach to cell and nucleus. The progress in cloning technology, brought the anticipation of the ability to clone an organism from each somatic cell nucleus. Therefore, the 'Cell Theory' is about to take the additional statement as "An organism arises from every nucleus". The development of gene targeting procedures which can be applied with SCNT, showed us that it may be possible to obtain different versions of the original genetic constitution of a cell. Because of this opportunity which is provided by SCNT, in reproductive cloning, it would be possible to clone enhanced organisms which can adapt to different environmental conditions and survive. Furthermore, regaining the genetic characteristics of ancestors or reverse herediter variations would be possible. On the other hand, in therapeutic cloning, more precise and easily obtainable alternatives for cell replacement therapy could be presented. However, while producing healthier or different organisms from a nucleus, it is hard to foresee the side effects influencing natural processes in long term is rather difficult.

  1. ULTRASTRUCTURE OF THE RAT MESENCEPHALIC TRIGEMINAL NUCLEUS

    NARCIS (Netherlands)

    LIEM, RSB; COPRAY, JCVM; VANWILLIGEN, JD

    1991-01-01

    The subcellular morphology of the mesencephalic trigeminal (Me5) nucleus in the rat was studied by transmission electron microscopy. Most neurons in the thin rostral as well as in the major caudal part of Me5 appeared as large (40-50-mu-m), round-to ovoid-shaped unipolar cells. A few neurons (estima

  2. Gravitational Corrections to Energy-Levels of a Hydrogen Atom

    Institute of Scientific and Technical Information of China (English)

    ZHAO Zhen-Hua; LIU Yu-Xiao; LI Xi-Guo

    2007-01-01

    The first-order perturbations of the energy levels of a hydrogen atom in central internal gravitational field are investigated.The internal gravitational field is produced by the mass of the atomic nucleus.The energy shifts are calculated for the relativistic 1S,2S,2P,3S,3P,3D,4S,and 4P levels with Schwarzschild metric.The calculated results show that the gravitational corrections are sensitive to the total angular momentum quantum number.

  3. Explicitly correlated wave function for a boron atom

    CERN Document Server

    Puchalski, Mariusz; Pachucki, Krzysztof

    2015-01-01

    We present results of high-precision calculations for a boron atom's properties using wave functions expanded in the explicitly correlated Gaussian basis. We demonstrate that the well-optimized 8192 basis functions enable a determination of energy levels, ionization potential, and fine and hyperfine splittings in atomic transitions with nearly parts per million precision. The results open a window to a spectroscopic determination of nuclear properties of boron including the charge radius of the proton halo in the $^8$B nucleus.

  4. Measurements of the Near-Nucleus Coma of Comet 67P/Churyumov-Gerasimenko with the Alice Far-Ultraviolet Spectrograph on Rosetta

    CERN Document Server

    Feldman, Paul D; Bertaux, Jean-Loup; Feaga, Lori M; Parker, Joel Wm; Schindhelm, Eric; Steffl, Andrew J; Stern, S Alan; Weaver, Harold A; Sierks, Holger; Vincent, Jean-Baptiste

    2015-01-01

    Aims. The Alice far-ultraviolet spectrograph onboard Rosetta is designed to observe emissions from various atomic and molecular species from within the coma of comet 67P/ Churyumov-Gerasimenko and to determine their spatial distribution and evolution with time and heliocentric distance. Methods. Following orbit insertion in August 2014, Alice made observations of the inner coma above the limbs of the nucleus of the comet from cometocentric distances varying between 10 and 80 km. Depending on the position and orientation of the slit relative to the nucleus, emissions of atomic hydrogen and oxygen were initially detected. These emissions are spatially localized close to the nucleus and spatially variable with a strong enhancement above the comet's neck at northern latitudes. Weaker emission from atomic carbon and CO were subsequently detected. Results. Analysis of the relative line intensities suggests photoelectron impact dissociation of H2O vapor as the source of the observed H I and O I emissions. The electr...

  5. Hypoxia activates nucleus tractus solitarii neurons projecting to the paraventricular nucleus of the hypothalamus

    OpenAIRE

    King, T. Luise; Heesch, Cheryl M.; Clark, Catharine G.; Kline, David D.; Hasser, Eileen M.

    2012-01-01

    Peripheral chemoreceptor afferent information is sent to the nucleus tractus solitarii (nTS), integrated, and relayed to other brain regions to alter cardiorespiratory function. The nTS projects to the hypothalamic paraventricular nucleus (PVN), but activation and phenotype of these projections during chemoreflex stimulation is unknown. We hypothesized that activation of PVN-projecting nTS neurons occurs primarily at high intensities of hypoxia. We assessed ventilation and cardiovascular para...

  6. Forward-backward correlations in nucleus-nucleus collisions: baseline contributions from geometrical fluctuations

    OpenAIRE

    Konchakovski, V. P.; Hauer, M.; Torrieri, G.; Gorenstein, M. I.; Bratkovskaya, E. L.

    2008-01-01

    We discuss the effects of initial collision geometry and centrality bin definition on correlation and fluctuation observables in nucleus-nucleus collisions. We focus on the forward-backward correlation coefficient recently measured by the STAR Collaboration in Au+Au collisions at RHIC. Our study is carried out within two models: the Glauber Monte Carlo code with a `toy' wounded nucleon model and the hadron-string dynamics (HSD) transport approach. We show that strong correlations can arise du...

  7. Study of -nucleus interaction through the formation of -nucleus bound state

    Indian Academy of Sciences (India)

    V Jha; B J Roy; A Chatterjee; H Machner

    2006-05-01

    The question of possible existence of -mesic nuclei is quite intriguing. Answer to this question will deeply enrich our understanding of -nucleus interaction which is not so well-understood. We review the experimental efforts for the search of -mesic nuclei and describe the physics motivation behind it. We present the description of an experiment for the search of -nucleus bound state using the GeV proton beam, currently being performed at COSY.

  8. Centrality Dependence of Flow in High-Energy Nucleus-Nucleus Collisions

    Institute of Scientific and Technical Information of China (English)

    杨红艳; 周代翠; 杨纯斌; 蔡勖

    2002-01-01

    Directed flow and elliptic flow of final state particles in high-energy nucleus-nucleus collisions in the EMU01 experiment have been studied. The dependences of directed flow and elliptic flow on incident energy and impact centrality of outgoing particles are presented. The results exhibit strong dependence of flow on centrality and energy. We also suggest a more reliable way to determine the event plane resolution here.

  9. Fusion cross sections for reactions involving medium & heavy nucleus-nucleus systems

    OpenAIRE

    Atta, Debasis; Basu, D. N.

    2014-01-01

    Existing data on near-barrier fusion excitation functions of medium and heavy nucleus-nucleus systems have been analyzed using a simple diffused barrier formula derived assuming the Gaussian shape of the barrier height distributions. Fusion cross section is obtained by folding the Gaussian barrier distribution with the classical expression for the fusion cross section for a fixed barrier. The energy dependence of the fusion cross section, thus obtained, provides good description to the existi...

  10. Weak interaction and nucleus: the relationship keeps on; Interaction faible et noyau: l'histoire continue

    Energy Technology Data Exchange (ETDEWEB)

    Martino, J. [Subatech, Ecole des Mines de Nantes, 44 - Nantes (France); Frere, J.M.; Naviliat-Cuncic, O.; Volpe, C.; Marteau, J.; Lhuillier, D.; Vignaud, D.; Legac, R.; Marteau, J.; Legac, R

    2003-07-01

    This document gathers the lectures made at the Joliot-Curie international summer school in 2003 whose theme, that year, was the relationship between weak interaction and nucleus. There were 8 contributions whose titles are: 1) before the standard model: from beta decay to neutral currents; 2) the electro-weak theory and beyond; 3) testing of the standard model at low energies; 4) description of weak processes in nuclei; 5) 20.000 tonnes underground, an approach to the neutrino-nucleus interaction; 6) parity violation from atom to nucleon; 7) how neutrinos got their masses; and 8) CP symmetry.

  11. Asymptotic near-nucleus structure of the electron-interaction potential in local effective potential theories

    International Nuclear Information System (INIS)

    In local effective potential theories of electronic structure, the electron correlations due to the Pauli exclusion principle, Coulomb repulsion, and correlation-kinetic effects, are all incorporated in the local electron-interaction potential vee(r). In previous work, it has been shown that for spherically symmetric or sphericalized systems, the asymptotic near-nucleus expansion of this potential is vee(r)=vee(0)+βr+O(r2), with vee(0) being finite. By assuming that the Schroedinger and local effective potential theory wave functions are analytic near the nucleus of atoms, we prove the following via quantal density functional theory (QDFT): (i) Correlations due to the Pauli principle and Coulomb correlations do not contribute to the linear structure; (ii) these Pauli and Coulomb correlations contribute quadratically; (iii) the linear structure is solely due to correlation-kinetic effects, the contributions of these effects being determined analytically. We also derive by application of adiabatic coupling constant perturbation theory via QDFT (iv) the asymptotic near-nucleus expansion of the Hohenberg-Kohn-Sham theory exchange vx(r) and correlation vc(r) potentials. These functions also approach the nucleus linearly with the linear term of vx(r) being solely due to the lowest-order correlation kinetic effects, and the linear term of vc(r) being due solely to the higher-order correlation kinetic contributions. The above conclusions are equally valid for systems of arbitrary symmetry, provided spherical averages of the properties are employed

  12. Transverse momentum spectra in high-energy nucleus-nucleus, proton-nucleus and proton-proton collisions

    Institute of Scientific and Technical Information of China (English)

    XIE Wen-Jie

    2011-01-01

    The transverse momentum distributions of final-state particles produced in nucleus-nucleus (AA),proton-nucleus (pA),and proton-proton (pp) collisions at high energies are investigated using a multisource ideal gas model.Our calculated results show that the contribution of hard emission can be neglected in the study of transverse momentum spectra of charged pions and kaons produced in Cu-Cu collisions at (√SNN)=22.5 GeV.And if we consider the contribution of hard emission,the transverse momentum spectra of p and (P) produced in Cu-Cu collisions at (√SNN)=22.5 GeV,KsO produced in Pb-Pb collisions at 158 A GeV,J/ψ particles produced in p-Pb collisions at 400 GeV and π+,K+,p produced in proton-proton collisions at (√S)=200 GeV,can be described by the model,especially in the tail part of spectra.

  13. Asymptotics for Two-dimensional Atoms

    DEFF Research Database (Denmark)

    Nam, Phan Thanh; Portmann, Fabian; Solovej, Jan Philip

    2012-01-01

    We prove that the ground state energy of an atom confined to two dimensions with an infinitely heavy nucleus of charge $Z>0$ and $N$ quantum electrons of charge -1 is $E(N,Z)=-{1/2}Z^2\\ln Z+(E^{\\TF}(\\lambda)+{1/2}c^{\\rm H})Z^2+o(Z^2)$ when $Z\\to \\infty$ and $N/Z\\to \\lambda$, where $E^{\\TF}(\\lambd......We prove that the ground state energy of an atom confined to two dimensions with an infinitely heavy nucleus of charge $Z>0$ and $N$ quantum electrons of charge -1 is $E(N,Z)=-{1/2}Z^2\\ln Z+(E^{\\TF}(\\lambda)+{1/2}c^{\\rm H})Z^2+o(Z^2)$ when $Z\\to \\infty$ and $N/Z\\to \\lambda$, where $E......^{\\TF}(\\lambda)$ is given by a Thomas-Fermi type variational problem and $c^{\\rm H}\\approx -2.2339$ is an explicit constant. We also show that the radius of a two-dimensional neutral atom is unbounded when $Z\\to \\infty$, which is contrary to the expected behavior of three-dimensional atoms....

  14. Atom Skimmers and Atom Lasers Utilizing Them

    Science.gov (United States)

    Hulet, Randall; Tollett, Jeff; Franke, Kurt; Moss, Steve; Sackett, Charles; Gerton, Jordan; Ghaffari, Bita; McAlexander, W.; Strecker, K.; Homan, D.

    2005-01-01

    Atom skimmers are devices that act as low-pass velocity filters for atoms in thermal atomic beams. An atom skimmer operating in conjunction with a suitable thermal atomic-beam source (e.g., an oven in which cesium is heated) can serve as a source of slow atoms for a magneto-optical trap or other apparatus in an atomic-physics experiment. Phenomena that are studied in such apparatuses include Bose-Einstein condensation of atomic gases, spectra of trapped atoms, and collisions of slowly moving atoms. An atom skimmer includes a curved, low-thermal-conduction tube that leads from the outlet of a thermal atomic-beam source to the inlet of a magneto-optical trap or other device in which the selected low-velocity atoms are to be used. Permanent rare-earth magnets are placed around the tube in a yoke of high-magnetic-permeability material to establish a quadrupole or octupole magnetic field leading from the source to the trap. The atoms are attracted to the locus of minimum magnetic-field intensity in the middle of the tube, and the gradient of the magnetic field provides centripetal force that guides the atoms around the curve along the axis of the tube. The threshold velocity for guiding is dictated by the gradient of the magnetic field and the radius of curvature of the tube. Atoms moving at lesser velocities are successfully guided; faster atoms strike the tube wall and are lost from the beam.

  15. Hadron production in the nucleus fragmentation region

    Energy Technology Data Exchange (ETDEWEB)

    Betemps, Marcos Andre [Universidade Federal de Pelotas, RS (Brazil). Conjunto Agrotecnico Visconde da Graca]. E-mail: marcos.betemps@ufpel.edu.br; Ducati, Maria Beatriz Gay [Universidade Federal de Pelotas, RS (Brazil)]. E-mail: beatriz.gay@ufrgs.br

    2008-09-15

    The RHIC hadron production data in hadronic collisions at the forward rapidities may hint the evidence of the Color Glass Condensate (CGC). However, in the opposite region, backward rapidities, new effects should be important in order to describe the observables. In this work, the charged hadron and {pi}{sup 0} productions are investigated in the fragmentation region of the nucleus (backward rapidities) considering dAu and pp collisions in the context of the Color Glass Condensate. In the backward rapidity region, only the proton can be treated as a CGC, and the large x nuclear effects need to be considered in order to describe the cross section. The results are shown by means of the nuclear modification ratio comparing the proton-nucleus and proton-proton cross sections and such ratio presents some dependences on the large x nuclear effects. (author)

  16. Single pion production in neutrino nucleus scattering

    CERN Document Server

    Hernández, E; Vacas, M J Vicente

    2013-01-01

    We study one pion production in both charged and neutral current neutrino nucleus scattering for neutrino energies below 2 GeV. We use a theoretical model for one pion production at the nucleon level that we correct for medium effects. The results are incorporated into a cascade program that apart from production also includes the pion final state interaction inside the nucleus. Besides, in some specific channels coherent pion production is also possible and we evaluate its contribution as well. Our results for total and differential cross sections are compared with recent data from the MiniBooNE Collaboration. The model provides an overall acceptable description of data, better for NC than for CC channels, although theory is systematically below data. Differential cross sections, folded with the full neutrino flux, show that most of the missing pions lie on the forward direction and at high energies.

  17. Protein quality control in the nucleus

    DEFF Research Database (Denmark)

    Nielsen, Sofie V.; Poulsen, Esben Guldahl; Rebula, Caio A.;

    2014-01-01

    to aggregate, cells have evolved several elaborate quality control systems to deal with these potentially toxic proteins. First, various molecular chaperones will seize the misfolded protein and either attempt to refold the protein or target it for degradation via the ubiquitin-proteasome system...... to be particularly active in protein quality control. Thus, specific ubiquitin-protein ligases located in the nucleus, target not only misfolded nuclear proteins, but also various misfolded cytosolic proteins which are transported to the nucleus prior to their degradation. In comparison, much less is known about...... these mechanisms in mammalian cells. Here we highlight recent advances in our understanding of nuclear protein quality control, in particular regarding substrate recognition and proteasomal degradation....

  18. Coherency in Neutrino-Nucleus Elastic Scattering

    CERN Document Server

    Kerman, S; Deniz, M; Wong, H T; Chen, J -W; Li, H B; Lin, S T; Liu, C -P; Yue, Q

    2016-01-01

    Neutrino-nucleus elastic scattering provides a unique laboratory to study the quantum mechanical coherency effects in electroweak interactions, towards which several experimental programs are being actively pursued. We report results of our quantitative studies on the transitions towards decoherency. A parameter ($\\alpha$) is identified to describe the degree of coherency, and its variations with incoming neutrino energy, detector threshold and target nucleus are studied. The ranges of $\\alpha$ which can be probed with realistic neutrino experiments are derived, indicating complementarity between projects with different sources and targets. Uncertainties in nuclear physics and in $\\alpha$ would constrain sensitivities in probing physics beyond the standard model. The maximum neutrino energies corresponding to $\\alpha$>0.95 are derived.

  19. Coherency in neutrino-nucleus elastic scattering

    Science.gov (United States)

    Kerman, S.; Sharma, V.; Deniz, M.; Wong, H. T.; Chen, J.-W.; Li, H. B.; Lin, S. T.; Liu, C.-P.; Yue, Q.; Texono Collaboration

    2016-06-01

    Neutrino-nucleus elastic scattering provides a unique laboratory to study the quantum mechanical coherency effects in electroweak interactions, towards which several experimental programs are being actively pursued. We report results of our quantitative studies on the transitions towards decoherency. A parameter (α ) is identified to describe the degree of coherency, and its variations with incoming neutrino energy, detector threshold, and target nucleus are studied. The ranges of α that can be probed with realistic neutrino experiments are derived, indicating complementarity between projects with different sources and targets. Uncertainties in nuclear physics and in α would constrain sensitivities in probing physics beyond the standard model. The maximum neutrino energies corresponding to α >0.95 are derived.

  20. Correlations in neutrino-nucleus scattering

    CERN Document Server

    Van Cuyck, Tom; Jachowicz, Natalie; González-Jiménez, Raul; Martini, Marco; Ryckebusch, Jan; Van Dessel, Nils

    2016-01-01

    We present a detailed study of charged-current quasielastic neutrino-nucleus scattering and of the influence of correlations on one- and two-nucleon knockout processes. The quasielastic neutrino-nucleus scattering cross sections, including the influence of long-range correlations, are evaluated within a continuum random phase approximation approach. The short-range correlation formalism is implemented in the impulse approximation by shifting the complexity induced by the correlations from the wave functions to the operators. The model is validated by confronting $(e,e^\\prime)$ cross-section predictions with electron scattering data in the kinematic region where the quasielastic channel is expected to dominate. Further, the $^{12}$C$(\

  1. Nickel-48, a very magic nucleus

    International Nuclear Information System (INIS)

    Ni48, which is doubly magic and very exotic, has been observed in an experiment performed at the GANIL accelerator. This nucleus, which is composed of 20 neutrons and 28 protons, is the most neutron-deficient nucleus that can be obtained, its decay mode has not yet been determined but theory predicts a 2-proton emission. Ni48 nuclei were obtained when accelerated (75 MeV/A) Ni58 ions had undergone fragmentation on natural nickel target. During this experiment 4 nuclei of Ni48 were produced as well as other very exotic nuclei: 90 nuclei of Ni49, 50 of Fe45 and 290 of Cr42. This experiment lasted 10 days and 1017 Ni58 ions were projected on the target. (A.C.)

  2. Hadron production in the nucleus fragmentation region

    International Nuclear Information System (INIS)

    The RHIC hadron production data in hadronic collisions at the forward rapidities may hint the evidence of the Color Glass Condensate (CGC). However, in the opposite region, backward rapidities, new effects should be important in order to describe the observables. In this work, the charged hadron and π0 productions are investigated in the fragmentation region of the nucleus (backward rapidities) considering dAu and pp collisions in the context of the Color Glass Condensate. In the backward rapidity region, only the proton can be treated as a CGC, and the large x nuclear effects need to be considered in order to describe the cross section. The results are shown by means of the nuclear modification ratio comparing the proton-nucleus and proton-proton cross sections and such ratio presents some dependences on the large x nuclear effects. (author)

  3. Nucleus spectroscopy: extreme masses and deformations

    International Nuclear Information System (INIS)

    The author proposes a synthesis of research activities performed since 1995 in the field of experimental nuclear physics, and more particularly in the investigation of two nucleus extreme states: deformation on the one hand, heavy and very heavy nuclei on the other hand. After a presentation of the context of investigations on deformation, rotation, and heavy nuclei, he gives an overview of developments regarding instruments (gamma spectrometers, detection of fission fragments, and detection at the focal plane of spectrometers or separators) and analysis techniques. Experiments and results are then reported and discussed, concerning super-deformed states with a high angular moment, spectroscopy of neutron-rich nuclei, very heavy nuclei close to nucleus map borders. He finally draws perspectives for middle and long term studies on the heaviest nuclei

  4. The fast Ice Nucleus chamber FINCH

    Science.gov (United States)

    Bundke, U.; Nillius, B.; Jaenicke, R.; Wetter, T.; Klein, H.; Bingemer, H.

    2008-11-01

    We present first results of our new developed Ice Nucleus (IN) counter FINCH from the sixth Cloud and Aerosol Characterization Experiment (CLACE 6) campaign at Jungfraujoch station, 3571 m asl. Measurements were made at the total and the ICE CVI inlet. Laboratory measurements of ice onset temperatures by FINCH are compared to those of the static diffusion chamber FRIDGE (FRankfurt Ice Deposition Freezing Experiment). Within the errors of both new instruments the results compare well to published data.

  5. Control of nucleus accumbens activity with neurofeedback

    OpenAIRE

    Greer, Stephanie M.; Trujillo, Andrew J.; Glover, Gary H.; Knutson, Brian

    2014-01-01

    The nucleus accumbens (NAcc) plays critical roles in healthy motivation and learning, as well as in psychiatric disorders (including schizophrenia and attention deficit hyperactivity disorder). Thus, techniques that confer control of NAcc activity might inspire new therapeutic interventions. By providing second-to-second temporal resolution of activity in small subcortical regions, functional magnetic resonance imaging (fMRI) can resolve online changes in NAcc activity, which can then be pres...

  6. Development of a Mobile Ice Nucleus Counter

    Energy Technology Data Exchange (ETDEWEB)

    Kok, Gregory; Kulkarni, Gourihar

    2014-07-10

    An ice nucleus counter has been constructed. The instrument uses built-in refrigeration systems for wall cooling. A cascade refrigeration system will allow the cold wall to operate as low as -70 deg C, and a single stage system can operate the warm wall at -45 deg C. A unique optical particle counter has been constructed using polarization detection of the scattered light. This allows differentiation of the particles exiting the chamber to determine if they are ice or liquid.

  7. Revisiting the supratrigeminal nucleus in the rat.

    Science.gov (United States)

    Fujio, T; Sato, F; Tachibana, Y; Kato, T; Tomita, A; Higashiyama, K; Ono, T; Maeda, Y; Yoshida, A

    2016-06-01

    The supratrigeminal nucleus (Vsup), originally proposed as a premotoneuron pool in the trigeminal reflex arc, is a key structure of jaw movement control. Surprisingly, however, the location of the rat Vsup has not precisely been defined. In light of our previous cat studies, we made two hypotheses regarding the rat Vsup: (1) the Vsup is cytoarchitectonically distinguishable from its surrounding structures; (2) the Vsup receives central axon terminals of the trigeminal mesencephalic nucleus (Vmes) neurons which are primary afferents innervating muscle spindles of jaw-closing muscles and periodontal ligaments around the teeth. To test the first hypothesis, we examined the cytoarchitecture of the rat Vsup. The Vsup was identified as an area medially adjacent to the dorsomedial part of trigeminal principal sensory nucleus (Vp), and extended from the level just rostral to the caudal two-thirds of the trigeminal motor nucleus (Vmo) to the level approximately 150μm caudal to the Vmo. Our rat Vsup was much smaller and its location was considerably different in comparison to the Vsup reported previously. To evaluate the second hypothesis, we tested the distribution patterns of Vmes primary afferent terminals in the cytoarchitectonically identified Vsup. After transganglionic tracer applications to the masseter, deep temporal, and medial pterygoid nerves, a large number of axon terminals were observed in all parts of Vsup (especially in its medial part). After applications to the inferior alveolar, infraorbital, and lingual nerves, a small number of axon terminals were labeled in the caudolateral Vsup. The Vsup could also be identified electrophysiologically. After electrical stimulation of the masseter nerve, evoked potentials with slow negative component were isolated only in the Vsup. The present findings suggest that the rat Vsup can be cytoarchitectonically and electrophysiologically identified, receives somatotopic termination of the trigeminal primary afferents, and

  8. Neutrino-nucleus CCQE-like scattering

    CERN Document Server

    Nieves, J; Simo, I Ruiz; Sanchez, F; Vacas, M J Vicente

    2014-01-01

    RPA correlations, spectral function and 2p2h (multi-nucleon) effects on charged-current neutrino-nucleus reactions without emitted pions are discussed. We pay attention to the influence of RPA and multi-nucleon mechanisms on the MiniBooNE and MINERvA flux folded differential cross sections, the MiniBooNE flux unfolded total cross section and the neutrino energy reconstruction.

  9. Radiative corrections to pion-nucleus bremsstrahlung

    OpenAIRE

    Kaiser, N.(Physik Department T39, Technische Universität München, Garching, D-85747, Germany); Friedrich, J. M.

    2008-01-01

    We calculate the one-photon loop radiative corrections to virtual pion Compton scattering $\\pi^- \\gamma^* \\to \\pi^- \\gamma$, that subprocess which determines in the one-photon exchange approximation the pion-nucleus bremsstrahlung reaction $\\pi^- Z\\to \\pi^- Z \\gamma$. Ultraviolet and infrared divergencies of the loop integrals are both treated by dimensional regularization. Analytical expressions for the ${\\cal O}(\\alpha)$ corrections to the virtual Compton scattering amplitudes, $A(s,u,Q)$ a...

  10. Theoretical highlights of neutrino-nucleus interactions

    CERN Document Server

    Alvarez-Ruso, Luis

    2009-01-01

    The recent theoretical developments in the field of neutrino-nucleus interactions in the few-GeV region are reviewed based on the presentations made at the NuInt09 Workshop. The topics of electron scattering and its connections with neutrino interactions, neutrino induced quasielastic scattering and pion production (coherent and incoherent) are covered, with special emphasis on the challenges that arise in the comparison with new experimental data.

  11. Efficient nucleus detector in histopathology images.

    Science.gov (United States)

    Vink, J P; Van Leeuwen, M B; Van Deurzen, C H M; De Haan, G

    2013-02-01

    In traditional cancer diagnosis, (histo)pathological images of biopsy samples are visually analysed by pathologists. However, this judgment is subjective and leads to variability among pathologists. Digital scanners may enable automated objective assessment, improved quality and reduced throughput time. Nucleus detection is seen as the corner stone for a range of applications in automated assessment of (histo)pathological images. In this paper, we propose an efficient nucleus detector designed with machine learning. We applied colour deconvolution to reconstruct each applied stain. Next, we constructed a large feature set and modified AdaBoost to create two detectors, focused on different characteristics in appearance of nuclei. The proposed modification of AdaBoost enables inclusion of the computational cost of each feature during selection, thus improving the computational efficiency of the resulting detectors. The outputs of the two detectors are merged by a globally optimal active contour algorithm to refine the border of the detected nuclei. With a detection rate of 95% (on average 58 incorrectly found objects per field-of-view) based on 51 field-of-view images of Her2 immunohistochemistry stained breast tissue and a complete analysis in 1 s per field-of-view, our nucleus detector shows good performance and could enable a range of applications in automated assessment of (histo)pathological images. PMID:23252774

  12. The nucleus basalis in Huntington's disease.

    Science.gov (United States)

    Clark, A W; Parhad, I M; Folstein, S E; Whitehouse, P J; Hedreen, J C; Price, D L; Chase, G A

    1983-10-01

    The nucleus basalis of Meynert (nbM) provides most of the cholinergic input to the cerebral cortex. The loss of cortical choline acetyltransferase (CAT) activity in Alzheimer's disease (AD) and senile dementia of the Alzheimer's type (SDAT) appears to be related to a severe depopulation of the nbM in this dementia. In Huntington's disease (HD), by contrast, there is no loss of cortical CAT activity. The present quantitative study indicates that (1) there is no significant loss of neurons from the nbM in HD, and (2) that the previously described cytologic changes in the neurons of this nucleus in HD patients do not differ significantly from controls. These findings are consistent with the working hypothesis that the types of dementia associated with reductions of neocortical CAT activity are characterized by dysfunction or death of neurons in the nbM, but dementing disorders with normal neocortical CAT activity manifest no major abnormalities in this cholinergic nucleus of the basal forebrain. PMID:6225032

  13. Actomyosin contractility rotates the cell nucleus

    CERN Document Server

    Kumar, Abhishek; Sumit, Madhuresh; Ramaswamy, Sriram; Shivashankar, G V

    2013-01-01

    The nucleus of the eukaryotic cell functions amidst active cytoskeletal filaments, but its response to the stresses carried by these filaments is largely unexplored. We report here the results of studies of the translational and rotational dynamics of the nuclei of single fibroblast cells, with the effects of cell migration suppressed by plating onto fibronectin-coated micro-fabricated patterns. Patterns of the same area but different shapes and/or aspect ratio were used to study the effect of cell geometry on the dynamics. On circles, squares and equilateral triangles, the nucleus undergoes persistent rotational motion, while on high-aspect-ratio rectangles of the same area it moves only back and forth. The circle and the triangle showed respectively the largest and the smallest angular speed. We show that our observations can be understood through a hydrodynamic approach in which the nucleus is treated as a highly viscous inclusion residing in a less viscous fluid of orientable filaments endowed with active...

  14. Experimental studies of pion-nucleus interactions at intermediate energies. Annual progress report

    Energy Technology Data Exchange (ETDEWEB)

    1992-12-31

    This report summarizes investigations of various pion-nucleus interactions and nucleon-nucleus charge-exchange reactions. The work was carried out with the LAMPF accelerator at the Los Alamos National Laboratory and the cyclotrons at the Paul Scherrer Institute (PSI) near Zurich, Switzerland, and at Indiana University (IUCF), as a collaborative effort among several laboratories and universities. The experimental activity at LAMPF involved measurements of new data on pion double-charge-exchange scattering, some initial work on a new Neutral Meson Spectrometer system, a search for deeply-bound pionic atoms, measurements of elastic scattering, and studies of the (n,p) reaction on various nuclei. At PSI measurements of pion quasielastic scattering were carried out, with detection of the recoil proton. Work on the analysis of data from a previous experiment at PSI on pion absorption in nuclei was continued. This experiment involved using a detector system that covered nearly the full solid angle.

  15. X detection in heavy ion induced reactions. Application to the lifetime measurement of a compound nucleus

    International Nuclear Information System (INIS)

    The ionization of inner electronic shells can be used to determine the lifetime of a compound nucleus formed in a nuclear reaction. The principle of the measure is based on the comparison between the unknown lifetime of the nuclear process and the known lifetime of a K-shell vacancy created during the collision. Besides testing this method, which we call the ''atomic-clok'' method with the compound nucleus 112Te formed by the reaction 20Ne (205 MeV) + 92Mo, the work in this thesis basically consists of a description and a study of the problems presented by the use of X-ray spectroscopy in nuclear-decay-time measurements and Z-identification of heavy nuclear products

  16. Chain reaction. History of the atomic bomb

    International Nuclear Information System (INIS)

    Henri becquerel tracked down in 1896 a strange radiation, which was called radioactivity by Marie Curie. In the following centuries German scientists Max Planck, Albert Einstein and Werner Heisenberg presented fundamental contributions to understand processes in the atomic nucleus. At Goettingen, center of the international nuclear physics community, the American student J. Robert Oppenheimer admit to this physical research. In the beginning of 1939 the message of Otto Hahns' nuclear fission electrified researchers. The first step, unleashing atomic energy, was done. A half year later the Second World War begun. And suddenly being friend with and busily communicating physicians were devided into hostile power blocs as bearers of official secrets. The author tells in this exciting book the story of the first atomic bomb as a chain reaction of ideas, discoveries and visions, of friendships, jealousy and intrigues of scientists, adventurers and genius. (orig./GL)

  17. Ionization of atoms by slow heavy particles

    CERN Document Server

    Roberts, B M; Gribakin, G F

    2016-01-01

    Atoms and molecules can become ionized during the scattering of a slow, heavy particle off a bound electron. Such an interaction involving leptophilic weakly interacting massive particles (WIMPs) is a promising possible explanation for the anomalous 9 sigma annual modulation in the DAMA dark matter direct detection experiment [R. Bernabei et al., Eur. Phys. J. C 73, 2648 (2013)]. We demonstrate the applicability of the Born approximation for such an interaction by showing its equivalence to the semiclassical adiabatic treatment of atomic ionization by slow-moving WIMPs. Conventional wisdom has it that the ionization probability for such a process should be exponentially small. We show, however, that due to nonanalytic, cusp-like behaviour of Coulomb functions close to the nucleus this suppression is removed, leading to an effective atomic structure enhancement. We also show that electron relativistic effects actually give the dominant contribution to such a process, meaning that nonrelativistic calculations m...

  18. Low P sub T hadron-nucleus interactions

    Science.gov (United States)

    Holynski, R.; Wozniak, K.

    1985-01-01

    The possibility of describing hadron-nucleus (hA) interactions is discussed in terms of a number of independent collisions of the projectile inside the target nucleus. This multiple rescattering may occur on a particle or quark parton level. To investigate the characteristics of hA interactions as a function of antineutrinos advantage is taken of the correlation between the average number antineutrinos of collisions of the projectile inside the nucleus and the number Ng of fast protons ejected from the struck nucleus. The relation antineutrinos vs Ng obtained in antineutrinos was used. For a given target nucleus this allows the selection of interactions occurring at different impact parameters.

  19. Formation of proton-fragments in hadron-nucleus and nucleus-nucleus collisions at high energies

    International Nuclear Information System (INIS)

    Full text: The investigation of production of protons in hadron- and nucleus-nucleus interactions is a key problem allowing one to establish the singularities of dynamics of nuclear interactions. The formation of proton-fragments at high energies of colliding particles proceeds within both the interaction of hadrons with nuclei and in the process of decay of the nucleus or its de-excitation at peripheral interactions. At different stages of interaction of impinging particle with target nucleus, the different mechanisms of formation of proton-fragments: the direct knock-out of intranuclear nucleons in the process of high energy cascade of an initial hadron, intranuclear cascade of produced particles, decay of the excited multi-nucleon fragments and of the thermalized remnant nucleus, and the coalescence of nuclear fragments to the new clusters are realized with the certain probability, connected to the interaction parameters (the interaction energy, the parameter of collision, the intranuclear density, the configuration of Fermi momentum of nucleons and clusters of target nucleus et al.). In its turn, the mechanisms of formation of the final nuclear fragments are closely related to the type of excitation of an initial nucleus. The peripheral interactions proceed at small transfers of the momentum of an impinging particle and represent the wide class of reactions covering the processes from diffractive or coulomb collective excitations of the whole nucleus to the direct quasi-elastic knock-out of the separate nucleons. Non-peripheral interactions are caused by comparatively high local transfers of momentum to the intranuclear clusters allowing the development of intranuclear cascade and the asymmetric redistribution of energy of an impinging particle. The central collisions causing the full decay of nucleus on nucleons or few-nucleon fragments, are the limiting case of the maximal development of the intranuclear cascade. The interaction of the initial particles with

  20. J/ψ production in proton-nucleus and nucleus-nucleus interactions at the CERN SPS

    International Nuclear Information System (INIS)

    The NA38 and NA50 experiments at the CERN SPS have measured charmonium production in different colliding systems with the aim of observing a phase transition from ordinary hadronic matter towards a state in which quarks and gluons are deconfined (Quark Gluon Plasma, QGP). This experimental research is based on the prediction that the J/ψ yield should be suppressed in deconfined matter. The analysis of the data collected by the NA50 experiment with Pb-Pb collisions at 158 GeV/c per nucleon shows that the J/ψ is anomalously suppressed with respect to the pattern observed in proton-nucleus and light ion reactions. (orig.)

  1. Method for laser spectroscopy of metastable pionic helium atoms

    International Nuclear Information System (INIS)

    The PiHe collaboration is currently attempting to carry out laser spectroscopy of metastable pionic helium atoms using the high-intensity π− beam of the ring cyclotron facility of the Paul Scherrer Institute. These atoms are heretofore hypothetical three-body Coulomb systems each composed of a helium nucleus, a π− occupying a Rydberg state, and an electron occupying the 1s ground state. We briefly review the proposed method by which we intend to detect the laser spectroscopic signal. This complements our experiments on metastable antiprotonic helium atoms at CERN

  2. Method for laser spectroscopy of metastable pionic helium atoms

    Energy Technology Data Exchange (ETDEWEB)

    Hori, M., E-mail: Masaki.Hori@mpq.mpg.de; Sótér, A.; Aghai-Khozani, H. [Max-Planck-Institut für Quantenoptik (Germany); Barna, D. [CERN (Switzerland); Dax, A. [Paul Scherrer Institut (Switzerland); Hayano, R. S.; Murakami, Y.; Yamada, H. [University of Tokyo, Department of Physics (Japan)

    2015-08-15

    The PiHe collaboration is currently attempting to carry out laser spectroscopy of metastable pionic helium atoms using the high-intensity π{sup −} beam of the ring cyclotron facility of the Paul Scherrer Institute. These atoms are heretofore hypothetical three-body Coulomb systems each composed of a helium nucleus, a π{sup −} occupying a Rydberg state, and an electron occupying the 1s ground state. We briefly review the proposed method by which we intend to detect the laser spectroscopic signal. This complements our experiments on metastable antiprotonic helium atoms at CERN.

  3. Laser Spectroscopy of Muonic Atoms and Ions

    CERN Document Server

    Pohl, Randolf; Fernandes, Luis M P; Ahmed, Marwan Abdou; Amaro, Fernando D; Amaro, Pedro; Biraben, François; Cardoso, João M R; Covita, Daniel S; Dax, Andreas; Dhawan, Satish; Diepold, Marc; Franke, Beatrice; Galtier, Sandrine; Giesen, Adolf; Gouvea, Andrea L; Götzfried, Johannes; Graf, Thomas; Hänsch, Theodor W; Hildebrandt, Malte; Indelicato, Paul; Julien, Lucile; Kirch, Klaus; Knecht, Andreas; Knowles, Paul; Kottmann, Franz; Krauth, Julian J; Bigot, Eric-Olivier Le; Liu, Yi-Wei; Lopes, José A M; Ludhova, Livia; Machado, Jorge; Monteiro, Cristina M B; Mulhauser, Françoise; Nebel, Tobias; Rabinowitz, Paul; Santos, Joaquim M F dos; Santos, José Paulo; Schaller, Lukas A; Schuhmann, Karsten; Schwob, Catherine; Szabo, Csilla I; Taqqu, David; Veloso, João F C A; Voss, Andreas; Weichelt, Birgit; Antognini, Aldo

    2016-01-01

    Laser spectroscopy of the Lamb shift (2S-2P energy difference) in light muonic atoms or ions, in which one negative muon $\\mu^-$ is bound to a nucleus, has been performed. The measurements yield significantly improved values of the root-mean-square charge radii of the nuclei, owing to the large muon mass, which results in a vastly increased muon wave function overlap with the nucleus. The values of the proton and deuteron radii are 10 and 3 times more accurate than the respective CODATA values, but 7 standard deviations smaller. Data on muonic helium-3 and -4 ions is being analyzed and will give new insights. In future, the (magnetic) Zemach radii of the proton and the helium-3 nuclei will be determined from laser spectroscopy of the 1S hyperfine splittings, and the Lamb shifts of muonic Li, Be and B can be used to improve the respective charge radii.

  4. Oscillations of moments in high-energy nucleus-nucleus collisions

    Institute of Scientific and Technical Information of China (English)

    杨红艳; 周代翠; 钱琬燕; 王晓荣

    2001-01-01

    The definitions of density function and moment of multiplicity distribution are introduced,and the method of moment analysis in e+ e- and proton-proton (pp) interactions is extended into nu-cleus-nucleus (AA) interactions. We analyze the data for relativistic nucleus-nucleus collisions and cal-culate the values of Hq for charged particle multiplicity distributions, by which we study systematically the dependences of Hq on incident energy, mass of colliding system, pseudorapidity interval, centrality and truncation of multiplicity. We compare the oscillation structures induced by e + e-, pp and AA inter-actions, and the comparison and analysis are carried out between experimental data and QCD predic-tion. The latest results are given in this paper.

  5. Study on chemical equilibrium in nucleus-nucleus collisions at relativistic energies

    CERN Document Server

    Manninen, J; Keränen, A; Gazdzicki, M; Stock, R; Manninen, Jaakko; Becattini, Francesco; Keranen, Antti; Gazdzicki, Marek; Stock, Reinhard

    2004-01-01

    We present a detailed study of chemical freeze-out in nucleus-nucleus collisions at beam energies of 11.6, 30, 40, 80 and 158A GeV. By analyzing hadronic multiplicities within the statistical hadronization approach, we have studied the chemical equilibration of the system as a function of center of mass energy and of the parameters of the source. Additionally, we have tested and compared different versions of the statistical model, with special emphasis on possible explanations of the observed strangeness hadronic phase space under-saturation.

  6. The effect of the relative nuclear size on the nucleus-nucleus interactions

    Science.gov (United States)

    Erofeeva, I. N.; Murzin, V. S.; Sivoklokov, S. Y.; Smirnova, L. N.

    1985-01-01

    The experimental data on the interactions of light nuclei (d, He(4), C(12)) at the momentum 4.2 GeV/cA with the carbon nuclei were taken in the 2-m propane bubble chamber. The distributions in the number of interacting nucleons, the spectra of protons, the mean energies of secondary pions and protons, the mean fractions of energy transferred to the pion and nucleon components are presented. The results of the investigation of the mechanism of nucleus-nucleus interactions can be used to calculate the nuclear cascades in the atmosphere.

  7. Nucleus-nucleus potential, energy dissipation and mass dispersion in fusion and transfer reactions

    CERN Document Server

    Washiyama, Kouhei; Ayik, Sakir

    2009-01-01

    The nucleus-nucleus potential and energy dissipation in fusion reactions are obtained from microscopic mean-field dynamics. The deduced potentials nicely reproduce the one extracted from experimental data. Energy dissipation shows a universal behaviour between different reactions. Also, the dispersion of mass distribution in transfer reaction is investigated in a stochastic mean-field dynamics. By including initial fluctuations in collective space, the description of the dispersion is much improved compared to that of mean field only. The result is consistent with the macroscopic phenomenological analysis of the experimental data.

  8. Aspects of Coulomb dissociation and interference in peripheral nucleus-nucleus collisions

    Energy Technology Data Exchange (ETDEWEB)

    Nystrand, Joakim; Baltz, Anthony; Klein, Spencer R.

    2001-10-21

    Coherent vector meson production in peripheral nucleus-nucleus collisions is discussed. These interactions may occur for impact parameters much larger than the sum of the nuclear radii. Since the vector meson production is always localized to one of the nuclei, the system acts as a two-source interferometer in the transverse plane. By tagging the outgoing nuclei for Coulomb dissociation it is possible to obtain a measure of the impact parameter and thus the source separation in the interferometer. This is of particular interest since the life-time of the vector mesons are generally much shorter than the impact parameters of the collisions.

  9. Azimuthal correlations of hadrons and fragments in nucleus-nucleus collisions

    Institute of Scientific and Technical Information of China (English)

    LI Hui-Ling

    2011-01-01

    Two-particle (two-fragment) azimuthal correlation functions are studied by using a simple formula which describes uniformly azimuthal distributions of final-state charged particles and nuclear fragments.This formula is obtained in the framework of a multi-source thermal model (or multi-source ideal gas model).The calculated results are compared and found to be in agreement with the experimental data of charged hadrons and nuclear fragments in nucleus-nucleus collisions at intermediate and high energies.

  10. Dynamical aspects of intermediate-energy nucleus-nucleus collisions. Pt. 4

    International Nuclear Information System (INIS)

    The production of pions in intermediate energy nucleus-nucleus collisions by incoherent nucleon-nucleon collisions is studied within a microscopic quantal phase-space approach. Employing free production rates for the elementary process N+N → π+X experimental data for inclusive pion yields are approximately reproduced from 20-150 MeV/u within the first collision approximation. These results indicate that cooperative phenomena - apart from the time-dependent mean field - seem to play a minor role for energetic particle production even at very low bombarding energy. (orig.)

  11. High energy nucleus--nucleus studies at the Berkeley Bevalac. [Survey

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, L.S.

    1976-09-01

    A survey of high-energy nucleus--nucleus experiments performed at the Berkeley Bevalac Facility is presented. Experimental results are divided into the general areas of peripheral and central collisions. Results on projectile and target fragmentation, total cross-section measurements, pion and photon production, and charged-particle multiplicities are stressed. Recently, there have been theoretical predictions concerning the possibility of observing new phenomena such as shock waves, pion condensates, or collapsed nuclear matter. Existing data relevant to some of these speculations are discussed. A brief discussion of future developments with high-energy nuclear beams is also presented. 27 figures, 1 table.

  12. Dust activity of Comet Halley's nucleus

    Science.gov (United States)

    Keller, H. U.; Delamere, W. A.; Huebner, W. F.; Reitsema, H.; Schmidt, H. U.; Schmidt, W. K. H.; Whipple, Fred L.; Wilhelm, K.

    1986-01-01

    Images obtained by the Halley multicolor camera using the clear filter with a pass band from 300 to 1000 nm were used to study dust activity in the comet nucleus. Comparisons with ground based observations confirm that dust production towards the Sun increases in activity relative to the southern background source while the Giotto spacecraft was approaching. This is in agreement with the assumption that the sunward activity becomes stronger when the source rotates towards the Sun. Estimated dust column density is 90 billion/sqm, with optical thickness less than or = 0.3. Surface reflectivity is less than 1%, indicating a very rough surface with large fractions of shadowed areas.

  13. Unveiling the nucleus of NGC 7172

    Science.gov (United States)

    Smajić, S.; Fischer, S.; Zuther, J.; Eckart, A.

    2012-08-01

    Aims: We present the results of near-infrared (NIR) H + K European Southern Observatory SINFONI integral field spectroscopy (IFS) of the Seyfert 2 galaxy NGC 7172. We investigate the central 800 pc, concentrating on excitation conditions, morphology, and stellar content. NGC 7172 was selected from a sample of the ten nearest Seyfert 2 galaxies from the Veron-Cetty & Veron catalogue. All objects were chosen as test cases for adaptive optics (AO) assisted observations that allow a detailed study (at high spatial and spectral resolution) of the nuclear and host environments. NGC 7172 has a prominent dustlane crossing the central galaxy region from east to west, which makes it an ideal candidate to investigate the effect of obscuration by strong galactic extinction on (active) galaxies and their classification. Methods: The NIR is less influenced by dust extinction than optical light and is sensitive to the mass-dominating stellar populations. SINFONI integral field spectroscopy combines NIR imaging and spectroscopy and provides us with the opportunity to analyze several emission and absorption lines to investigate the stellar populations and ionization mechanisms over the 4″ × 4″ field of view (FOV). Results: We present emission and absorption line measurements in the central 800 pc of NGC 7172. The detection of [Si vi] and broad Paα and Brγ components are clear signs of an accreting super-massive black hole hiding behind the prominent dustlane at visible wavelengths. Hot temperatures of about 1300 K are indicative of a dusty torus in the nuclear region. Narrow components of Paα and Brγ enable us to make an extinction measurement. Our measures of the molecular hydrogen lines, hydrogen recombination lines, and [Fe ii] indicate that the excitation of these lines is caused by an active galactic nucleus. The central region of the galactic disk is predominantly inhabited by gas, dust, and an old K-M type giant stellar population. The gaseous, molecular, and

  14. A thalamic input to the nucleus accumbens mediates opiate dependence.

    Science.gov (United States)

    Zhu, Yingjie; Wienecke, Carl F R; Nachtrab, Gregory; Chen, Xiaoke

    2016-02-11

    Chronic opiate use induces opiate dependence, which is characterized by extremely unpleasant physical and emotional feelings after drug use is terminated. Both the rewarding effects of a drug and the desire to avoid withdrawal symptoms motivate continued drug use, and the nucleus accumbens is important for orchestrating both processes. While multiple inputs to the nucleus accumbens regulate reward, little is known about the nucleus accumbens circuitry underlying withdrawal. Here we identify the paraventricular nucleus of the thalamus as a prominent input to the nucleus accumbens mediating the expression of opiate-withdrawal-induced physical signs and aversive memory. Activity in the paraventricular nucleus of the thalamus to nucleus accumbens pathway is necessary and sufficient to mediate behavioural aversion. Selectively silencing this pathway abolishes aversive symptoms in two different mouse models of opiate withdrawal. Chronic morphine exposure selectively potentiates excitatory transmission between the paraventricular nucleus of the thalamus and D2-receptor-expressing medium spiny neurons via synaptic insertion of GluA2-lacking AMPA receptors. Notably, in vivo optogenetic depotentiation restores normal transmission at these synapses and robustly suppresses morphine withdrawal symptoms. This links morphine-evoked pathway- and cell-type-specific plasticity in the paraventricular nucleus of the thalamus to nucleus accumbens circuit to opiate dependence, and suggests that reprogramming this circuit holds promise for treating opiate addiction.

  15. "Bohr's Atomic Model."

    Science.gov (United States)

    Willden, Jeff

    2001-01-01

    "Bohr's Atomic Model" is a small interactive multimedia program that introduces the viewer to a simplified model of the atom. This interactive simulation lets students build an atom using an atomic construction set. The underlying design methodology for "Bohr's Atomic Model" is model-centered instruction, which means the central model of the…

  16. Experimental study of collective flow phenomena in high-energy nucleus-nucleus collisions

    CERN Document Server

    Chkhaidze, L V; Kharkhelauri, L L

    2002-01-01

    The results of the experimental study of collective flow phenomena, such as the sideward and elliptic flow of nuclear matter, discovered during the last 10-15 years in high-energy nucleus-nucleus collisions are presented in this review. Sideward (often termed directed) and elliptic flows have been observed for protons, antiprotons, light nuclei, pions, kaons, and lambdas emitted in nucleus-nucleus collisions at 0.1-1.8 GeV/nucleon of LBL Bevalac and GSI/SIS by Plastic-Ball, Streamer Chamber, EOS-NPC, FOPI, LAND, TAPS, and KAOS collaborations; at 2-4 GeV/nucleon of Dubna JINR by SKM-200-GIBS, Propane Buble Chamber, and Emulsion Chamber collaborations; at 2-14 GeV/nucleon of BNL AGS, by the E877, E895, and E917 collaborations; and at 60 and 200 GeV/nucleon of CERN SPS, by the WA98 and NA49 collaborations and more recently by the STAR at RHIC BNL. In the review, the results of the SKM-200-GIBS collaboration of JINR are presented and compared with the results of different experiments by Bevalac, GSI/SIS, BNL, and...

  17. Thermal Bremsstrahlung probing nuclear multifragmentation in nucleus-nucleus collisions around the Fermi energy

    International Nuclear Information System (INIS)

    The thermodynamical properties of nuclear matter at moderate temperatures and densities, in the vicinity of the predicted nuclear liquid-gas phase transition, are studied using as experimental probe the hard-photons (Eγ > 30 MeV) emitted in nucleus-nucleus collisions. Photon and charged-particle production in four different heavy-ion reactions (Ar36 + Au197, Ag107, Ni58, C12 at 60 A*MeV) is measured exclusively and inclusively coupling the TAPS photon spectrometer with two charged-particle and intermediate-mass-fragment detectors covering nearly 4π. We confirm that Bremsstrahlung emission in first-chance (off-equilibrium) proton-neutron collisions (pnγ) is the dominant origin of hard photons. We also firmly establish the existence of a thermal radiation component emitted in second-chance proton-neutron collisions. This thermal Bremsstrahlung emission takes place in semi-central and central nucleus-nucleus reactions involving heavy targets. We exploit this observation i) to demonstrate that thermal equilibrium is reached during the reaction, ii) to establish a new thermometer of nuclear matter based on Bremsstrahlung photons, iii) to derive the thermodynamical properties of the excited nuclear sources and, in particular, to establish a 'caloric curve' (temperature versus excitation energy), and iv) to assess the time-scales of the nuclear break-up process. (author)

  18. Radiative corrections to pion-nucleus bremsstrahlung

    CERN Document Server

    Kaiser, N

    2008-01-01

    We calculate the one-photon loop radiative corrections to virtual pion Compton scattering $\\pi^- \\gamma^* \\to \\pi^- \\gamma$, that subprocess which determines in the one-photon exchange approximation the pion-nucleus bremsstrahlung reaction $\\pi^- Z\\to \\pi^- Z \\gamma$. Ultraviolet and infrared divergencies of the loop integrals are both treated by dimensional regularization. Analytical expressions for the ${\\cal O}(\\alpha)$ corrections to the virtual Compton scattering amplitudes, $A(s,u,Q)$ and $B(s,u,Q)$, are derived with their full dependence on the (small) photon virtuality $Q$ from 9 classes of contributing one-loop diagrams. Infrared finiteness of these virtual radiative corrections is achieved (in the standard way) by including soft photon radiation below an energy cut-off $\\lambda$. In the region of low $\\pi^- \\gamma$ center-of-mass energies, where the pion-nucleus bremsstrahlung process is used to extract the pion electric and magnetic polarizabilities, we find radiative corrections up to about -3% fo...

  19. Caudal topographic nucleus isthmi and the rostral nontopographic nucleus isthmi in the turtle, Pseudemys scripta.

    Science.gov (United States)

    Sereno, M I; Ulinski, P S

    1987-07-15

    Isthmotectal projections in turtles were examined by making serial section reconstructions of axonal and dendritic arborizations that were anterogradely or retrogradely filled with HRP. Two prominent tectal-recipient isthmic nuclei--the caudal magnocellular nucleus isthmi (Imc) and the rostral magnocellular nucleus isthmi (Imr)--exhibited strikingly different patterns of organization. Imc cells have flattened, bipolar dendritic fields that cover a few percent of the area of the cell plate constituting the nucleus and they project topographically to the ipsilateral tectum without local axon branches. The topography was examined explicitly at the single-cell level by using cases with two injections at widely separated tectal loci. Each Imc axon terminates as a compact swarm of several thousand boutons placed mainly in the upper central gray and superficial gray layers. One Imc terminal spans less that 1% of the tectal surface. Imr cells, by contrast, have large, sparsely branched dendritic fields overlapped by local axon collaterals while distally, their axons nontopographically innervate not only the deeper layers of the ipsilateral tectum but also ipsilateral Imc. Imr receives a nontopographic tectal input that contrasts with the topographic tectal input to Imc. Previous work on nucleus isthmi emphasized the role of the contralateral isthmotectal projection (which originates from a third isthmic nucleus in turtles) in mediating binocular interactions in the tectum. The present results on the two different but overlapping ipsilateral tecto-isthmo-tectal circuits set up by Imc and Imr are discussed in the light of physiological evidence for selective attention effects and local-global interactions in the tectum.

  20. Teach us atom structure

    International Nuclear Information System (INIS)

    This book is written to teach atom structure in very easy way. It is divided into nine chapters, which indicates what is the components of matter? when we divide matter continuously, it becomes atom, what did atom look like? particles comprised of matter is not only atom, discover of particles comprised of atom, symbol of element, various radiation, form alchemy to nuclear transmutation, shape of atom is evolving. It also has various pictures in each chapters to explain easily.

  1. Teach us atom structure

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Suh Yeon

    2006-08-15

    This book is written to teach atom structure in very easy way. It is divided into nine chapters, which indicates what is the components of matter? when we divide matter continuously, it becomes atom, what did atom look like? particles comprised of matter is not only atom, discover of particles comprised of atom, symbol of element, various radiation, form alchemy to nuclear transmutation, shape of atom is evolving. It also has various pictures in each chapters to explain easily.

  2. Physical role for the nucleus in cell migration.

    Science.gov (United States)

    Fruleux, Antoine; Hawkins, Rhoda J

    2016-09-14

    Cell migration is important for the function of many eukaryotic cells. Recently the nucleus has been shown to play an important role in cell motility. After giving an overview of cell motility mechanisms we review what is currently known about the mechanical properties of the nucleus and the connections between it and the cytoskeleton. We also discuss connections to the extracellular matrix and mechanotransduction. We identify key physical roles of the nucleus in cell migration. PMID:27406341

  3. Physical role for the nucleus in cell migration

    Science.gov (United States)

    Fruleux, Antoine; Hawkins, Rhoda J.

    2016-09-01

    Cell migration is important for the function of many eukaryotic cells. Recently the nucleus has been shown to play an important role in cell motility. After giving an overview of cell motility mechanisms we review what is currently known about the mechanical properties of the nucleus and the connections between it and the cytoskeleton. We also discuss connections to the extracellular matrix and mechanotransduction. We identify key physical roles of the nucleus in cell migration.

  4. Atomic phase diagram

    Institute of Scientific and Technical Information of China (English)

    LI Shichun

    2004-01-01

    Based on the Thomas-Fermi-Dirac-Cheng model, atomic phase diagram or electron density versus atomic radius diagram describing the interaction properties of atoms of different kinds in equilibrium state is developed. Atomic phase diagram is established based on the two-atoms model. Besides atomic radius, electron density and continuity condition for electron density on interfaces between atoms, the lever law of atomic phase diagram involving other physical parameters is taken into account, such as the binding energy, for the sake of simplicity.

  5. Hydrogen atom wave function and eigen energy in the Rindler space

    CERN Document Server

    Dai, De-Chang

    2016-01-01

    We study the hydrogen atom eigenstate energy and wave function in the Rindler space. The probability distribution is tilted because the electric field of the nucleus is no longer spherically symmetric. The hydrogen atom therefore cannot be treated exactly in the same way as what it is in an inertial frame. We also find that if the external force accelerates only the nucleus and then the nucleus accelerates its surrounding electrons through electromagnetic force, the electrons can tunnel through the local energy gap and split the hydrogen atom into an ion. This is similar to what one expects from the Stark effect. However, the critical acceleration is about $3\\times 10^{22} m/s^2$. It is well beyond the gravitational acceleration on a regular star surface.

  6. Hydrogen atom wave function and eigen energy in the Rindler space

    Science.gov (United States)

    Dai, De-Chang

    2016-10-01

    We study the hydrogen atom eigenstate energy and wave function in the Rindler space. The probability distribution is tilted because the electric field of the nucleus is no longer spherically symmetric. The hydrogen atom therefore cannot be treated exactly in the same way as what it is in an inertial frame. We also find that if the external force accelerates only the nucleus and then the nucleus accelerates its surrounding electrons through electromagnetic force, the electrons can tunnel through the local energy gap and split the hydrogen atom into an ion. This is similar to what one expects from the Stark effect. However, the critical acceleration is about 3 ×1022 m /s2. It is well beyond the gravitational acceleration on a regular star surface.

  7. Cold Matter Assembled Atom-by-Atom

    CERN Document Server

    Endres, Manuel; Keesling, Alexander; Levine, Harry; Anschuetz, Eric R; Krajenbrink, Alexandre; Senko, Crystal; Vuletic, Vladan; Greiner, Markus; Lukin, Mikhail D

    2016-01-01

    The realization of large-scale fully controllable quantum systems is an exciting frontier in modern physical science. We use atom-by-atom assembly to implement a novel platform for the deterministic preparation of regular arrays of individually controlled cold atoms. In our approach, a measurement and feedback procedure eliminates the entropy associated with probabilistic trap occupation and results in defect-free arrays of over 50 atoms in less than 400 ms. The technique is based on fast, real-time control of 100 optical tweezers, which we use to arrange atoms in desired geometric patterns and to maintain these configurations by replacing lost atoms with surplus atoms from a reservoir. This bottom-up approach enables controlled engineering of scalable many-body systems for quantum information processing, quantum simulations, and precision measurements.

  8. Analysis of Intermediate-Energy Nucleus-Nucleus Spallation, Fission, and Fragmentation Reactions with the LAQGSM code

    OpenAIRE

    Mashnik, S. G.; Gudima, K. K.; Prael, R. E.; Sierk, A. J.

    2003-01-01

    The LAQGSM code has been recently developed at Los Alamos National Laboratory to simulate nuclear reactions for proton radiography applications. We have benchmarked our code against most available measured data both for proton-nucleus and nucleus-nucleus interactions at incident energies from 10 MeV to 800 GeV and have compared our results with predictions of other current models used by the nuclear community. Here, we present a brief description of our code and show illustrative results obta...

  9. Atomic processes in matter-antimatter interactions

    International Nuclear Information System (INIS)

    Atomic processes dominate antiproton stopping in matter at nearly all energies of interest. They significantly influence or determine the antiproton annihilation rate at all energies around or below several MeV. This article reviews what is known about these atomic processes. For stopping above about 10 eV the processes are antiproton-electron collisions, effective at medium keV through high MeV energies, and elastic collisions with atoms and adiabatic ionization of atoms, effective from medium eV through low keB energies. For annihilation above about 10 eV is the enhancement of the antiproton annihilation rate due to the antiproton-nucleus coulomb attraction, effective around and below a few tens of MeV. At about 10 eV and below, the atomic rearrangement/annihilation process determines both the stopping and annihilation rates. Although a fair amount of theoretical and some experimental work relevant to these processes exist, there are a number of energy ranges and material types for which experimental data does not exist and for which the theoretical information is not as well grounded or as accurate as desired. Additional experimental and theoretical work is required for accurate prediction of antiproton stopping and annihilation for energies and material relevant to antiproton experimentation and application

  10. Laser-Nucleus Interactions: The Quasiadiabatic Regime

    CERN Document Server

    Pálffy, Adriana; Hoefer, Axel; Weidenmüller, Hans A

    2015-01-01

    The interaction between nuclei and a strong zeptosecond laser pulse with coherent MeV photons is investigated theoretically. We provide a first semi-quantitative study of the quasiadiabatic regime where the photon absorption rate is comparable to the nuclear equilibration rate. In that regime, multiple photon absorption leads to the formation of a compound nucleus in the so-far unexplored regime of excitation energies several hundred MeV above the yrast line. The temporal dynamics of the process is investigated by means of a set of master equations that account for dipole absorption, stimulated dipole emission, neutron decay and induced fission in a chain of nuclei. That set is solved numerically by means of state-of-the-art matrix exponential methods also used in nuclear fuel burnup and radioactivity transport calculations. Our quantitative estimates predict the excitation path and range of nuclei reached by neutron decay and provide relevant information for the layout of future experiments.

  11. Nature of multiple-nucleus cluster galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Merritt, D.

    1984-05-01

    In models for the evolution of galaxy clusters which include dynamical friction with the dark binding matter, the distribution of galaxies becomes more concentrated to the cluster center with time. In a cluster like Coma, this evolution could increase by a factor of approximately 3 the probability of finding a galaxy very close to the cluster center, without decreasing the typical velocity of such a galaxy significantly below the cluster mean. Such an enhancement is roughly what is needed to explain the large number of first-ranked cluster galaxies which are observed to have extra ''nuclei''; it is also consistent with the high velocities typically measured for these ''nuclei.'' Unlike the cannibalism model, this model predicts that the majority of multiple-nucleus systems are transient phenomena, and not galaxies in the process of merging.

  12. Suprachiasmatic Nucleus: Cell Autonomy and Network Properties

    Science.gov (United States)

    Welsh, David K.; Takahashi, Joseph S.; Kay, Steve A.

    2013-01-01

    The suprachiasmatic nucleus (SCN) is the primary circadian pacemaker in mammals. Individual SCN neurons in dispersed culture can generate independent circadian oscillations of clock gene expression and neuronal firing. However, SCN rhythmicity depends on sufficient membrane depolarization and levels of intracellular calcium and cAMP. In the intact SCN, cellular oscillations are synchronized and reinforced by rhythmic synaptic input from other cells, resulting in a reproducible topographic pattern of distinct phases and amplitudes specified by SCN circuit organization. The SCN network synchronizes its component cellular oscillators, reinforces their oscillations, responds to light input by altering their phase distribution, increases their robustness to genetic perturbations, and enhances their precision. Thus, even though individual SCN neurons can be cell-autonomous circadian oscillators, neuronal network properties are integral to normal function of the SCN. PMID:20148688

  13. Delta-nucleus dynamics: proceedings of symposium

    Energy Technology Data Exchange (ETDEWEB)

    Lee, T.S.H.; Geesaman, D.F.; Schiffer, J.P. (eds.)

    1983-10-01

    The appreciation of the role in nuclear physics of the first excited state of the nucleon, the delta ..delta..(1232), has grown rapidly in the past decade. The delta resonance dominates nuclear reactions induced by intermediate energy pions, nucleons, and electromagnetic probes. It is also the most important non-nucleonic degree of freedom needed to resolve many fundamental problems encountered in the study of low-energy nuclear phenomena. Clearly, a new phase of nuclear physics has emerged and conventional thinking must be extended to account for this new dimension of nuclear dynamics. The most challenging problem we are facing is how a unified theory can be developed to describe ..delta..-nucleus dynamics at all energies. In exploring this new direction, it is important to have direct discussions among researchers with different viewpoints. Separate entries were prepared for the 49 papers presented. (WHK)

  14. Delta-nucleus dynamics: proceedings of symposium

    International Nuclear Information System (INIS)

    The appreciation of the role in nuclear physics of the first excited state of the nucleon, the delta Δ(1232), has grown rapidly in the past decade. The delta resonance dominates nuclear reactions induced by intermediate energy pions, nucleons, and electromagnetic probes. It is also the most important non-nucleonic degree of freedom needed to resolve many fundamental problems encountered in the study of low-energy nuclear phenomena. Clearly, a new phase of nuclear physics has emerged and conventional thinking must be extended to account for this new dimension of nuclear dynamics. The most challenging problem we are facing is how a unified theory can be developed to describe Δ-nucleus dynamics at all energies. In exploring this new direction, it is important to have direct discussions among researchers with different viewpoints. Separate entries were prepared for the 49 papers presented

  15. Lifetime Measurements in Chiral Nucleus 130Cs

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>The high spin states of the 130Cs were populated by the reaction 124Sn(11B, 5n)130Cs at a beam energy of 65 MeV. The 11B beam was provided by the HI-13 tandem accelerator in the China Institute of Atomic Energy. The target

  16. Alpha decay in electron environments of increasing density: From the bare nucleus to compressed matter

    Energy Technology Data Exchange (ETDEWEB)

    Belloni, Fabio [Institute for Transuranium Elements, European Commission, Joint Research Centre, Postfach 2340, Karlsruhe (Germany)

    2016-02-15

    The influence of the electron environment on the α decay is elucidated. Within the frame of a simple model based on the generalized Thomas-Fermi theory of the atom, it is shown that the increase of the electron density around the parent nucleus drives a mechanism which shortens the lifetime. Numerical results are provided for {sup 144}Nd, {sup 154}Yb and {sup 210}Po. Depending on the nuclide, fractional lifetime reduction relative to the bare nucleus is of the order of 0.1-1% in free ions, neutral atoms and ordinary matter, but may reach up to 10% at matter densities as high as 10{sup 4}g/cm{sup 3}, in a high-Z matrix. The effect induced by means of state-of-the-art compression techniques, although much smaller than previously found, would however be measurable. The extent of the effect in ultra-high-density stellar environments might become significant and would deserve further investigation. (orig.)

  17. Experimental investigation of linear-chain structured nucleus in 14C

    CERN Document Server

    Yamaguchi, H; Hayakawa, S; Sakaguchi, Y; Abe, K; Nakao, T; Suhara, T; Iwasa, N; Kim, A; Kim, D H; Cha, S M; Kwag, M S; Lee, J H; Lee, E J; Chae, K Y; Wakabayashi, Y; Imai, N; Kitamura, N; Lee, P; Moon, J Y; Lee, K B; Akers, C; Jung, H S; Duy, N N; Khiem, L H; Lee, C S

    2016-01-01

    It is a well-known fact that a cluster of nucleons can be formed in the interior of an atomic nucleus, and such clusters may occupy molecular-like orbitals, showing characteristics similar to normal molecules consisting of atoms. Chemical molecules having a linear alignment are commonly seen in nature, such as carbon dioxide. A similar linear alignment of the nuclear clusters, referred to as linear-chain cluster state (LCCS), has been studied since the 1950s, however, up to now there is no clear experimental evidence demonstrating the existence of such a state. Recently, it was proposed that an excess of neutrons may offer just such a stabilizing mechanism, revitalizing interest in the nuclear LCCS, specifically with predictions for their emergence in neutron-rich carbon isotopes. Here we present the experimental observation of {\\alpha}-cluster states in the radioactive 14C nucleus. Using the 10Be+{\\alpha} resonant scattering method with a radioactive beam, we observed a series of levels which completely agre...

  18. Heavy flavors in nucleus-nucleus collisions at RHIC and LHC

    Directory of Open Access Journals (Sweden)

    Nardi Marzia

    2014-04-01

    Full Text Available A multi-step setup for heavy-flavor studies in high-energy nucleus-nucleus (AA collisions — addressing within a comprehensive framework the initial QQ¯$Q\\overline Q $ production, the propagation in the hot medium until decoupling and the final hadronization and decays — is presented. The propagation of the heavy quarks in the medium is described in a framework provided by the relativistic Langevin equation and the corresponding numerical results are compared to experimental data from RHIC and the LHC. In particular, outcomes for the nuclear modification factor RAA and for the elliptic flow υ2 of D/B mesons, heavy-flavor electrons and non-prompt J/ψ’s are displayed.

  19. Experimental and phenomenological investigations of QCD matter in high-energy nucleus-nucleus collisions

    Energy Technology Data Exchange (ETDEWEB)

    Andronic, Anton

    2014-07-15

    This thesis is heterogeneous, comprising experimental papers at low energies (SIS-18 at GSI) and at the LHC, papers on phenomenology of high-energy nucleus-nucleus collisions, and papers on detectors. The overview covers the experimental papers and those on phenomenology. I have chosen to write it in a general manner, intended to be accessible to non-experts. It emphasizes recent measurements and their understanding at the LHC. The detector papers, which address many principle aspects of gaseous detectors, are summarized and placed in context in the review I co-wrote and which closes the stack. The detector papers included here are the outcome of an R and D program for the Transition Radiation Detector of ALICE.

  20. Forward-backward correlations in nucleus-nucleus collisions: baseline contributions from geometrical fluctuations

    CERN Document Server

    Konchakovski, V P; Torrieri, G; Gorenstein, M I; Bratkovskaya, E L

    2008-01-01

    We discuss the effects of initial collision geometry and centrality bin definition on correlation and fluctuation observables in nucleus-nucleus collisions. We focus on the forward-backward correlation coefficient recently measured by the STAR Collaboration in Au+Au collisions at RHIC. Our study is carried out within two models: the Glauber Monte Carlo code with a `toy' wounded nucleon model and the hadron-string dynamics (HSD) transport approach. We show that strong correlations can arise due to averaging over events in one centrality bin. We, furthermore, argue that a study of the dependence of correlations on the centrality bin definition as well as the bin size may distinguish between these `trivial' correlations and correlations arising from `new physics'.

  1. Dissipation and fluctuation of the relative momentum in nucleus-nucleus collisions

    International Nuclear Information System (INIS)

    The dissipation of the relative momentum in nucleus-nucleus collisions is treated in terms of a Langevin equation with a fluctuating force. Equations of motion for first and second moments of the macroscopic variables are derived directly from the Langevin equation. The properties of the fluctuating force which results from random particle exchange are investigated in detail. Drift and diffusion coefficients are calculated microscopically and analytical expressions are given which can be used in any trajectory calculation. An important feature of the model is that the Einstein relation between dissipation and fluctuation turns out to be only a limiting case of a more general expression which included nonthermal fluctuations. By treating the two nuclei as intrinsically equilibrated but not in thermal equilibrium with respect to each other several important aspects of the dissipative behaviour, seen in heavy ion collisions with final energies above the Coloumb barrier, can be understood. (orig.)

  2. Jet energy loss and bulk parton collectivity in nucleus-nucleus collisions at RHIC

    Institute of Scientific and Technical Information of China (English)

    HUANG Huan-Zhong

    2009-01-01

    Nucleus-nucleus collisions at RHIC produce high temperature and high energy density matter which exhibits paxtonic degrees of freedom. We will discuss measurements of nuclear modification factors for light hadrons and non-photonic electrons from heavy quark decays, which reflect the flavor dependence of energy loss of high momentum partons traversing the dense QCD medium. The dense QCD medium responds to energy loss of high momentum patrons in a pattern consistent with that expected from a hydrodynamic fluid. The hadronization of bulk partonic matter exhibits collectivity with effective partonic degrees of freedom. Nuclear collisions at RHIC provide an intriguing environment, where many constituent quark ingredients are readily available for possible formation of exotic particles through quark coalescence or recombinations.

  3. Nonmonotonic Target Excitation Dependence of Pion Clans in Relativistic Nucleus-Nucleus Collisions

    Science.gov (United States)

    Ghosh, Dipak; Deb, Argha; Dutta, Srimonti

    Target excitation dependence of fluctuation of produced pions (i.e. classifying data of the fluctuation pattern on pions on the basis of the number of gray tracks) is studied for nucleus-nucleus collisions at different projectile energies. In each set the experimental multiplicity distribution is compared with the negative binomial distribution (NBD), which is found to describe the experimental distribution quite well. Target excitation dependence is studied in respect of the clan model parameters bar {n}c and bar {N}, which are extracted from the NBD fit parameters bar {n} and k. A detailed comparison between different interactions at the same energy and the same interactions at different energies is also drawn. A nonmonotonic dependence of D2/bar {n} on is revealed, which is also a characteristic of multiplicity fluctuations at RHIC data.

  4. Production of cold fragments in nucleus-nucleus collisions in the Fermi-energy domain

    CERN Document Server

    Veselsky, M

    2007-01-01

    The reaction mechanism of nucleus-nucleus collisions at projectile energies around the Fermi energy is investigated with emphasis on the production of fragmentation-like residues. The results of simulations are compared to experimental mass distributions of elements with Z = 21 - 29 observed in the reactions 86Kr+124,112Sn at 25 AMeV. The model of incomplete fusion is modified and a component of excitation energy of the cold fragment dependent on isospin asymmetry is introduced. The modifications in the model of incomplete fusion appear consistent with both overall model framework and available experimental data. A prediction is provided for the production of very neutron-rich nuclei using a secondary beam of 132Sn where e.g. the reaction 132Sn+238U at 28 AMeV appears as a possible alternative to the use of fragmentation reactions at higher energies.

  5. Nuclear Effects in Neutrino-Nucleus Interactions and the MINERvA Neutrino Nucleus Scattering Program

    Science.gov (United States)

    Morfín, Jorge G.

    2011-09-01

    Nuclear effects of charged current deep inelastic neutrino-iron scattering have been studied in the frame-work of a χ2 analysis of parton distribution functions (PDFs)1. A set of iron PDFs have been extracted which are then used to compute xBj-dependent and Q2-dependent nuclear correction factors for iron structure functions which are required in global analyses of free nucleon PDFs. Upon comparing our results with nuclear correction factors from neutrino-nucleus scattering models and correction factors for l±-iron scattering we find that, except for very high xBj, our correction factors differ in both shape and magnitude from the correction factors of the models and charged-lepton scattering. The MINERvA neutrino-nucleus scattering experiment at Fermilab, will systematically study neutrino nuclear effects off of He, C, Fe and Pb for a more thorough A-dependent study of nuclear PDFs and these correction factors.

  6. Nucleus -nucleus interactions at a few GeV/C per nucleon

    International Nuclear Information System (INIS)

    Introduction: Since the period of the ancient Egyptians people are looking for unusual phenomena, which may enable to give interpretation for nature. Physicists believe that the study of A-A interactions will shed light on the mechanism of high-energy nuclear interactions. It is important to systematize the results of nucleus-nucleus interactions and to have an overall picture of cross-section, multiplicity-distributions, angular distributions, etc It is important to systematize the results of nucleus-nucleus interactions and to have an overall picture of: cross-section, multiplicity-distributions, angular distributions, etc Beams: Beams are mainly from Dubna Synchrophasotron including 1H, 2H, 3He, 4He, 12C, 160,22Ne, 24Mg, 28Si and 32S at 4.1∼ 4.5 GeV/c. Experimental Technique: Stacks of Br-2 emulsion were exposed to 4.1- 4.5 A GeV/c nuclei at Dubna Synchrophasotron. The pellicles of emulsion have the dimensions of 20 cm x 10 cm x 600 μm (undeveloped emulsion). The intensity of the beam was ≡104 particles/cm2 and the beam diameter was approximately 1 cm. The emitted particles are classified to:Shower tracks producing s-particleshaving a relative ionization I*≤ 1.4. Its multiplicity is denoted by ns after the exclusion of tracks having an emission angle θ≤3ο.Grey tracks producing g-particleshaving I* > 1.4 and L>3 mm. Its multiplicity is denoted by ng and does not include those tracks with an emission angle θ≤ 3ο. Black tracks producing b-particleshaving L b and does not include those tracks having an angle of emission θ≤3ο.The band gtracks are both called heavily ionizing tracks producing h-particlesand nh denotes its multiplicity

  7. A Frame Nucleus on a Two-side Prequantale

    Institute of Scientific and Technical Information of China (English)

    XUShao-xian; WANGShun-qin; MAFei-fei

    2004-01-01

    In this paper, a Frame nucleus and prime elements in a Prequantale are defined. The concrete structure of a Frame prequantic quotient is considered, and the relation between the half-prime element and the Frame nucleus in a two-side Prequantale are obtained.

  8. MULTIPHOTON IONIZATION OF ATOMS

    OpenAIRE

    Mainfray, G.

    1985-01-01

    Multiphoton ionization of one-electron atoms, such as atomic hydrogen and alkaline atoms, is well understood and correctly described by rigorous theoretical models. The present paper will be devoted to collisionless multiphoton ionization of many-electron atoms as rare gases. It induces removal of several electrons and the production of multiply charged ions. Up to Xe5+ ions are produced in Xe atoms. Doubly charged ions can be produced, either by simultaneous excitation of two electrons, or b...

  9. Stable atomic hydrogen: Polarized atomic beam source

    International Nuclear Information System (INIS)

    We have carried out experiments with stable atomic hydrogen with a view to possible applications in polarized targets or polarized atomic beam sources. Recent results from the stabilization apparatus are described. The first stable atomic hydrogen beam source based on the microwave extraction method (which is being tested ) is presented. The effect of the stabilized hydrogen gas density on the properties of the source is discussed. (orig.)

  10. Challenges in the description of the atomic nucleus: Unification and interdisciplinarity

    International Nuclear Information System (INIS)

    Nuclear physics, in general, and theoretical nuclear physics, in particular, have provided the physics community at large, among other things, with the paradigm of spontaneous symmetry breaking phenomena in finite many-body systems. The study of the associated mechanisms of symmetry restoration has shed light on the microscopic structure of the corresponding condensates, in particular on the superfluid phase, allowing to study Cooper pair tunnelling into superfluid nuclei (related to the Josephson effect), in terms of individual quantum states and reaching, in doing so, a new milestone: that of unifying structure and reactions, these last processes being found at the basis of the formulation of quantum mechanics (probability interpretation, Born). In the process, nuclear physicists have extended the validity of BCS theory of superconductivity to the single Cooper pair situation, let alone discovering unexpected mechanism to break gauge invariance. The insight obtained from pair transfer research is likely to have important consequences in the study of double charge exchange processes, and thus in the determination of the nuclear matrix element associated with neutrinoless double beta decay, eventually providing an important test of the Standard Model. Time, thus, seems ripe for nuclear theorists to take centre stage, backed by a wealth of experimental information and by their interdisciplinary capacity to connect basic physical concepts across the borders. With the help of these elements they can aim at fully revealing the many facets of their femtometer many-body system, from vacuum zero point fluctuations to new exotic modes of nuclear excitations and of their interweaving, resulting in powerful effective field theories. Unless. Unless they are not able to free themselves from words like ab initio or fundamental, and to adapt a relax attitude concerning Skyrme, tensor, etc., forces, as well as regarding the quest for ''the'' Hamiltonian. (orig.)

  11. Challenges in the description of the atomic nucleus: Unification and interdisciplinarity

    Science.gov (United States)

    Bortignon, P. F.; Broglia, R. A.

    2016-03-01

    Nuclear physics, in general, and theoretical nuclear physics, in particular, have provided the physics community at large, among other things, with the paradigm of spontaneous symmetry breaking phenomena in finite many-body systems. The study of the associated mechanisms of symmetry restoration has shed light on the microscopic structure of the corresponding condensates, in particular on the superfluid phase, allowing to study Cooper pair tunnelling into superfluid nuclei (related to the Josephson effect), in terms of individual quantum states and reaching, in doing so, a new milestone: that of unifying structure and reactions, these last processes being found at the basis of the formulation of quantum mechanics (probability interpretation, Born). In the process, nuclear physicists have extended the validity of BCS theory of superconductivity to the single Cooper pair situation, let alone discovering unexpected mechanism to break gauge invariance. The insight obtained from pair transfer research is likely to have important consequences in the study of double charge exchange processes, and thus in the determination of the nuclear matrix element associated with neutrinoless double beta decay, eventually providing an important test of the Standard Model. Time, thus, seems ripe for nuclear theorists to take centre stage, backed by a wealth of experimental information and by their interdisciplinary capacity to connect basic physical concepts across the borders. With the help of these elements they can aim at fully revealing the many facets of their femtometer many-body system, from vacuum zero point fluctuations to new exotic modes of nuclear excitations and of their interweaving, resulting in powerful effective field theories. Unless. Unless they are not able to free themselves from words like ab initio or fundamental, and to adapt a relax attitude concerning Skyrme, tensor, etc., forces, as well as regarding the quest for "the" Hamiltonian.

  12. Challenges in the description of the atomic nucleus: Unification and interdisciplinarity

    Energy Technology Data Exchange (ETDEWEB)

    Bortignon, P.F. [University of Milan, Department of Physics, Milan (Italy); INFN, Milan (Italy); Broglia, R.A. [University of Milan, Department of Physics, Milan (Italy); University of Copenhagen, The Niels Bohr Institute, Copenhagen (Denmark)

    2016-03-15

    Nuclear physics, in general, and theoretical nuclear physics, in particular, have provided the physics community at large, among other things, with the paradigm of spontaneous symmetry breaking phenomena in finite many-body systems. The study of the associated mechanisms of symmetry restoration has shed light on the microscopic structure of the corresponding condensates, in particular on the superfluid phase, allowing to study Cooper pair tunnelling into superfluid nuclei (related to the Josephson effect), in terms of individual quantum states and reaching, in doing so, a new milestone: that of unifying structure and reactions, these last processes being found at the basis of the formulation of quantum mechanics (probability interpretation, Born). In the process, nuclear physicists have extended the validity of BCS theory of superconductivity to the single Cooper pair situation, let alone discovering unexpected mechanism to break gauge invariance. The insight obtained from pair transfer research is likely to have important consequences in the study of double charge exchange processes, and thus in the determination of the nuclear matrix element associated with neutrinoless double beta decay, eventually providing an important test of the Standard Model. Time, thus, seems ripe for nuclear theorists to take centre stage, backed by a wealth of experimental information and by their interdisciplinary capacity to connect basic physical concepts across the borders. With the help of these elements they can aim at fully revealing the many facets of their femtometer many-body system, from vacuum zero point fluctuations to new exotic modes of nuclear excitations and of their interweaving, resulting in powerful effective field theories. Unless. Unless they are not able to free themselves from words like ab initio or fundamental, and to adapt a relax attitude concerning Skyrme, tensor, etc., forces, as well as regarding the quest for ''the'' Hamiltonian. (orig.)

  13. An Introduction to the Interacting Boson Model of the Atomic Nucleus, Part I

    CERN Document Server

    Pfeifer, Walter

    2002-01-01

    This work introduces to the Interacting Boson Model, which was created in 1974 by F. Iachello and A. Arima and then extend by numerous papers. Many-body configurations with s- and d-boson states are described and creation- and annihilation-operators for bosons are introduced. States with defined angular momentum are dealt with and the Hamilton operator of the IBM1-model is expressed in terms of Casimir operators. Level energies and electromagnetic transition probabilities are compared with measured data. A short introduction to Lie algebras and their application to the IBM1-model are given. In the IBM2-model protons and neutrons are treated separately and in IBFM single nucleons are added to the boson model. Comparison with experimental results.

  14. An Introduction to the Interacting Boson Model of the Atomic Nucleus. Part II

    CERN Document Server

    Pfeifer, Walter

    2002-01-01

    This work introduces to the Interacting Boson Model, which was created in 1974 by F. Iachello and A. Arima and then extended by numerous papers. Many-body configurations with s- and d-boson states are described and creation- and annihilation-operators for bosons are introduced. States with defined angular momentum are dealt with and the Hamilton operator of the IBM1-model is expressed in terms of Casimir operators. Level energies and electromagnetic transition probabilities are compared with measured data. A short introduction to Lie algebras and their application to the IBM1-model are given. In the IBM2-model protons and neutrons are treated separately and in IBFM single nucleons are added to the boson model. Comparison with experimental results.

  15. Advances in atomic spectroscopy

    CERN Document Server

    Sneddon, J

    2000-01-01

    This fifth volume of the successful series Advances in Atomic Spectroscopy continues to discuss and investigate the area of atomic spectroscopy.It begins with a description of the use of various atomic spectroscopic methods and applications of speciation studies in atomic spectroscopy. The emphasis is on combining atomic spectroscopy with gas and liquid chromatography. In chapter two the authors describe new developments in tunable lasers and the impact they will have on atomic spectroscopy. The traditional methods of detection, such as photography and the photomultiplier, and how they are being replaced by new detectors is discussed in chapter three. The very active area of glow discharge atomic spectrometry is presented in chapter four where, after a brief introduction and historical review, the use of glow discharge lamps for atomic spectroscopy and mass spectrometry are discussed. Included in this discussion is geometry and radiofrequency power. The future of this source in atomic spectroscopy is also dis...

  16. Atomic and molecular manipulation

    CERN Document Server

    Mayne, Andrew J

    2011-01-01

    Work with individual atoms and molecules aims to demonstrate that miniaturized electronic, optical, magnetic, and mechanical devices can operate ultimately even at the level of a single atom or molecule. As such, atomic and molecular manipulation has played an emblematic role in the development of the field of nanoscience. New methods based on the use of the scanning tunnelling microscope (STM) have been developed to characterize and manipulate all the degrees of freedom of individual atoms and molecules with an unprecedented precision. In the meantime, new concepts have emerged to design molecules and substrates having specific optical, mechanical and electronic functions, thus opening the way to the fabrication of real nano-machines. Manipulation of individual atoms and molecules has also opened up completely new areas of research and knowledge, raising fundamental questions of "Optics at the atomic scale", "Mechanics at the atomic scale", Electronics at the atomic scale", "Quantum physics at the atomic sca...

  17. Interpretation of Hund's multiplicity rule for the carbon atom.

    Science.gov (United States)

    Hongo, Kenta; Maezono, Ryo; Kawazoe, Yoshiyuki; Yasuhara, Hiroshi; Towler, M D; Needs, R J

    2004-10-15

    Hund's multiplicity rule is investigated for the carbon atom using quantum Monte Carlo methods. Our calculations give an accurate account of electronic correlation and obey the virial theorem to high accuracy. This allows us to obtain accurate values for each of the energy terms and therefore to give a convincing explanation of the mechanism by which Hund's rule operates in carbon. We find that the energy gain in the triplet with respect to the singlet state is due to the greater electron-nucleus attraction in the higher spin state, in accordance with Hartree-Fock calculations and studies including correlation. The method used here can easily be extended to heavier atoms.

  18. Spontaneous fission of superheavy nucleus $^{286}$Fl

    CERN Document Server

    Poenaru, Dorin N

    2016-01-01

    The decimal logarithm of spontaneous fission half-life of the superheavy nucleus $^{286}$Fl experimentally determined is $\\log_{10} T_f^{exp} (s) = -0.632$. We present a method to calculate the half-life based on the cranking inertia and the deformation energy, functions of two independent surface coordinates, using the best asymmetric two center shell model. In the first stage we study the statics. At a given mass asymmetry up to about $\\eta=0.5$ the potential barrier has a two hump shape, but for larger $\\eta$ it has only one hump. The touching point deformation energy versus mass asymmetry shows the three minima, produced by shell effects, corresponding to three decay modes: spontaneous fission, cluster decay and $\\alpha$~decay. The least action trajectory is determined in the plane $(R,\\eta)$ where $R$ is the separation distance of the fission fragments and $\\eta$ is the mass asymmetry. We may find a sequence of several trajectories one of which gives the least action. The parametrization with two deforma...

  19. Functional network inference of the suprachiasmatic nucleus.

    Science.gov (United States)

    Abel, John H; Meeker, Kirsten; Granados-Fuentes, Daniel; St John, Peter C; Wang, Thomas J; Bales, Benjamin B; Doyle, Francis J; Herzog, Erik D; Petzold, Linda R

    2016-04-19

    In the mammalian suprachiasmatic nucleus (SCN), noisy cellular oscillators communicate within a neuronal network to generate precise system-wide circadian rhythms. Although the intracellular genetic oscillator and intercellular biochemical coupling mechanisms have been examined previously, the network topology driving synchronization of the SCN has not been elucidated. This network has been particularly challenging to probe, due to its oscillatory components and slow coupling timescale. In this work, we investigated the SCN network at a single-cell resolution through a chemically induced desynchronization. We then inferred functional connections in the SCN by applying the maximal information coefficient statistic to bioluminescence reporter data from individual neurons while they resynchronized their circadian cycling. Our results demonstrate that the functional network of circadian cells associated with resynchronization has small-world characteristics, with a node degree distribution that is exponential. We show that hubs of this small-world network are preferentially located in the central SCN, with sparsely connected shells surrounding these cores. Finally, we used two computational models of circadian neurons to validate our predictions of network structure.

  20. Functional network inference of the suprachiasmatic nucleus

    Energy Technology Data Exchange (ETDEWEB)

    Abel, John H.; Meeker, Kirsten; Granados-Fuentes, Daniel; St. John, Peter C.; Wang, Thomas J.; Bales, Benjamin B.; Doyle, Francis J.; Herzog, Erik D.; Petzold, Linda R.

    2016-04-04

    In the mammalian suprachiasmatic nucleus (SCN), noisy cellular oscillators communicate within a neuronal network to generate precise system-wide circadian rhythms. Although the intracellular genetic oscillator and intercellular biochemical coupling mechanisms have been examined previously, the network topology driving synchronization of the SCN has not been elucidated. This network has been particularly challenging to probe, due to its oscillatory components and slow coupling timescale. In this work, we investigated the SCN network at a single-cell resolution through a chemically induced desynchronization. We then inferred functional connections in the SCN by applying the maximal information coefficient statistic to bioluminescence reporter data from individual neurons while they resynchronized their circadian cycling. Our results demonstrate that the functional network of circadian cells associated with resynchronization has small-world characteristics, with a node degree distribution that is exponential. We show that hubs of this small-world network are preferentially located in the central SCN, with sparsely connected shells surrounding these cores. Finally, we used two computational models of circadian neurons to validate our predictions of network structure.

  1. Functional network inference of the suprachiasmatic nucleus.

    Science.gov (United States)

    Abel, John H; Meeker, Kirsten; Granados-Fuentes, Daniel; St John, Peter C; Wang, Thomas J; Bales, Benjamin B; Doyle, Francis J; Herzog, Erik D; Petzold, Linda R

    2016-04-19

    In the mammalian suprachiasmatic nucleus (SCN), noisy cellular oscillators communicate within a neuronal network to generate precise system-wide circadian rhythms. Although the intracellular genetic oscillator and intercellular biochemical coupling mechanisms have been examined previously, the network topology driving synchronization of the SCN has not been elucidated. This network has been particularly challenging to probe, due to its oscillatory components and slow coupling timescale. In this work, we investigated the SCN network at a single-cell resolution through a chemically induced desynchronization. We then inferred functional connections in the SCN by applying the maximal information coefficient statistic to bioluminescence reporter data from individual neurons while they resynchronized their circadian cycling. Our results demonstrate that the functional network of circadian cells associated with resynchronization has small-world characteristics, with a node degree distribution that is exponential. We show that hubs of this small-world network are preferentially located in the central SCN, with sparsely connected shells surrounding these cores. Finally, we used two computational models of circadian neurons to validate our predictions of network structure. PMID:27044085

  2. The new magic nucleus 96Zr

    International Nuclear Information System (INIS)

    The 96Zr nucleus is expected to be magic due to the subshell closures at Z = 40 and N = 56. Recent gamma-spectroscopic studies involving in-beam techniques and beta decay certainly revealed a remarkably simple level pattern consisting of the 1,750 keV 2+ - 2,439 keV 3+ doublet, a few levels decaying to the 3- octupole state by strong E1 or E2 transitions, and a band built on the shape isomeric first excited 0+ state. While quadrupole vibrational collectivity is restricted to this latter intruder band the octupole mode is expected to be strong, according to systematics and an earlier lifetime result for the 3- state. since low-lying particle-hole excitations, and a strong octupole mode in particular, are typical for magic nuclei like 208Pb it is important to test to what extent 96Zr resembles the well known magic nuclei. In this paper, inelastic deuteron scattering and RPA studies show that the lowest states of doubly closed subshell 96Zr are particle-hole excitations, the first 2+ state being a neutron excitation of 3s1/2 2d5/2-1 type. The octupole collectively is enhanced by a factor of about two with respect to 90Zr due mainly to the contribution of 1h1 1/2 2d5/2-1 neutron excitations, suggesting an unusually high B(E3) value

  3. Observation of the antimatter helium-4 nucleus.

    Science.gov (United States)

    2011-05-19

    High-energy nuclear collisions create an energy density similar to that of the Universe microseconds after the Big Bang; in both cases, matter and antimatter are formed with comparable abundance. However, the relatively short-lived expansion in nuclear collisions allows antimatter to decouple quickly from matter, and avoid annihilation. Thus, a high-energy accelerator of heavy nuclei provides an efficient means of producing and studying antimatter. The antimatter helium-4 nucleus (4He), also known as the anti-α (α), consists of two antiprotons and two antineutrons (baryon number B = -4). It has not been observed previously, although the α-particle was identified a century ago by Rutherford and is present in cosmic radiation at the ten per cent level. Antimatter nuclei with B Collider (RHIC; ref. 6) in 10(9) recorded gold-on-gold (Au+Au) collisions at centre-of-mass energies of 200 GeV and 62 GeV per nucleon-nucleon pair. The yield is consistent with expectations from thermodynamic and coalescent nucleosynthesis models, providing an indication of the production rate of even heavier antimatter nuclei and a benchmark for possible future observations of 4He in cosmic radiation.

  4. Time reversal violating nuclear polarizability and atomic electric dipole moment

    International Nuclear Information System (INIS)

    Full text: We propose a nuclear mechanism which can induce an atomic electric dipole moment (EDM). The interaction of external electric E and magnetic H fields with nuclear electric and magnetic dipole moments, d and ,u, gives rise to an energy shift, U= -βik Ei Hk, where βik is the nuclear polarizability. Parity and time invariance violating (P,T-odd) nuclear forces generate a mixed P,T-odd nuclear polarizability, whereψ0 and ψn are P,T-odd perturbed ground and excited nuclear states, respectively. In the case of a heavy spherical nucleus with a single unpaired nucleon, the perturbed wavefunctions are U = -βikEiHk, where ξis a constant proportional to the strength of the nuclear P,T-odd interaction, σ is the nuclear spin operator, and ψn is an unperturbed wavefunction. There are both scalar and tensor contributions to the nuclear P,T-odd polarizability. An atomic EDM is induced by the interaction of the fields of an unpaired electron in an atom with the P,T-odd perturbed atomic nucleus. An estimate for the value of this EDM has been made. The measurements of atomic EDMs can provide information about P,T-odd nuclear forces and test models of CP-violation

  5. THE ORNL ATOM PROBE

    OpenAIRE

    Miller, M

    1986-01-01

    The ORNL Atom Probe is a microanalytical tool for studies in materials science. The instrument is a combination of a customized version of the vacuum system of the VG FIM-100 atom probe, an ORNL-designed microcomputer-controlled digital timing system, and a double curved CEMA Imaging Atom Probe detector. The atom probe combines four instruments into one - namely a field ion microscope, an energy compensated time-of-flight mass spectrometer, an imaging atom probe, and a pulsed laser atom probe.

  6. Nonthermal Fluctuations and Mechanics of the Active Cell Nucleus

    CERN Document Server

    Smith, K; Byrd, H; MacKintosh, F C; Kilfoil, M L

    2013-01-01

    We present direct measurements of fluctuations in the nucleus of yeast cells. While prior work has shown these fluctuations to be active and non-thermal in character, their origin and time dependence are not understood. We show that nuclear fluctuations can be quantitatively understood by uncorrelated, active force fluctuations driving a nuclear medium that is dominated by an uncondensed DNA solution, for which we perform rheological measurements on an in vitro model system under similar conditions to what is expected in the nucleus. We conclude that the eukaryotic nucleus of living cells is a nonequilibrium soft material whose fluctuations are actively driven, and are far from thermal in their time dependence.

  7. Variability of the Radio Nucleus of the Galaxy M81

    CERN Document Server

    Bietenholz, M F; Rupen, M P

    1997-01-01

    M81 is the nearest galaxy with an active galactic nucleus, with the possibly exception of Cen A. The nucleus is exceptionally compact. Here we present results from new VLA and VLBI observations of the nucleus of M81. The VLA shows that its flux density is variable by 50% on a timescale of weeks. The spectral index is also somewhat variable on the same timescale. The VLBI imaging results show that there is structure on scales <0.5 mas, and that this structure is variable, also on a timescale of weeks.

  8. Quarkonium-nucleus bound states from lattice QCD

    Energy Technology Data Exchange (ETDEWEB)

    Beane, S.  R. [Univ. of Washington, Seattle, WA (United States); Chang, E. [Univ. of Washington, Seattle, WA (United States); Cohen, S.  D. [Univ. of Washington, Seattle, WA (United States); Detmold, W. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Lin, H. -W. [Univ. of Washington, Seattle, WA (United States); Orginos, K. [College of William and Mary, Williamsburg, VA (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Parreño, A. [Univ., de Barcelona, Marti Franques (Spain); Savage, M.  J. [Univ. of Washington, Seattle, WA (United States)

    2015-06-11

    Quarkonium-nucleus systems are composed of two interacting hadronic states without common valence quarks, which interact primarily through multi-gluon exchanges, realizing a color van der Waals force. We present lattice QCD calculations of the interactions of strange and charm quarkonia with light nuclei. Both the strangeonium-nucleus and charmonium-nucleus systems are found to be relatively deeply bound when the masses of the three light quarks are set equal to that of the physical strange quark. Extrapolation of these results to the physical light-quark masses suggests that the binding energy of charmonium to nuclear matter is B < 40 MeV.

  9. Presenting the Bohr Atom.

    Science.gov (United States)

    Haendler, Blanca L.

    1982-01-01

    Discusses the importance of teaching the Bohr atom at both freshman and advanced levels. Focuses on the development of Bohr's ideas, derivation of the energies of the stationary states, and the Bohr atom in the chemistry curriculum. (SK)

  10. High precision spectroscopy of pionic and antiprotonic atoms; Spectroscopie de precision des atomes pioniques et antiprotoniques

    Energy Technology Data Exchange (ETDEWEB)

    El-Khoury, P

    1998-04-15

    The study of exotic atoms, in which an orbiting electron of a normal atom is replaced by a negatively charged particle ({pi}{sup -}, {mu}{sup -}, p, {kappa}{sup -}, {sigma}{sup -},...) may provide information on the orbiting particle and the atomic nucleus, as well as on their interaction. In this work, we were interested in pionic atoms ({pi}{sup -14} N) on the one hand in order to determine the pion mass with high accuracy (4 ppm), and on the other hand in antiprotonic atoms (pp-bar) in order to study the strong nucleon-antinucleon interaction at threshold. In this respect, a high-resolution crystal spectrometer was coupled to a cyclotron trap which provides a high stop density for particles in gas targets at low pressure. Using curved crystals, an extended X-ray source could be imaged onto the detector. Charge-Coupled Devices were used as position sensitive detectors in order to measure the Bragg angle of the transition to a high precision. The use of gas targets resolved the ambiguity owing to the number of K electrons for the value of the pion mass, and, for the first time, strong interaction shift and broadening of the 2p level in antiprotonic hydrogen were measured directly. (author)

  11. Antiprotonic Helium Atoms

    OpenAIRE

    Kartavtsev, O. I.

    1995-01-01

    Metastable antiprotonic helium atoms $^{3,4}\\! H\\! e\\bar pe$ have been discovered recently in experiments of the delayed annihilation of antiprotons in helium media. These exotic atoms survive for an enormous time (about tens of microseconds) and carry the extremely large total angular momentum $L\\sim 30-40$. The theoretical treatment of the intrinsic properties of antiprotonic helium atoms, their formation and collisions with atoms and molecules is discussed.

  12. Atomic Scale Plasmonic Switch

    OpenAIRE

    Emboras, A.; Niegemann, J.; Ma, P; Haffner, C; Pedersen, A.; Luisier, M.; Hafner, C; Schimmel, T.; Leuthold, J.

    2016-01-01

    The atom sets an ultimate scaling limit to Moore’s law in the electronics industry. While electronics research already explores atomic scales devices, photonics research still deals with devices at the micrometer scale. Here we demonstrate that photonic scaling, similar to electronics, is only limited by the atom. More precisely, we introduce an electrically controlled plasmonic switch operating at the atomic scale. The switch allows for fast and reproducible switching by means of the relocat...

  13. Atomizing nozzle and process

    Science.gov (United States)

    Anderson, Iver E.; Figliola, Richard S.; Molnar, Holly M.

    1992-06-30

    High pressure atomizing nozzle includes a high pressure gas manifold having a divergent expansion chamber between a gas inlet and arcuate manifold segment to minimize standing shock wave patterns in the manifold and thereby improve filling of the manifold with high pressure gas for improved melt atomization. The atomizing nozzle is especially useful in atomizing rare earth-transition metal alloys to form fine powder particles wherein a majority of the powder particles exhibit particle sizes having near-optimum magnetic properties.

  14. Atoms Talking to SQUIDs

    CERN Document Server

    Hoffman, J E; Kim, Z; Wood, A K; Anderson, J R; Dragt, A J; Hafezi, M; Lobb, C J; Orozco, L A; Rolston, S L; Taylor, J M; Vlahacos, C P; Wellstood, F C

    2011-01-01

    We present a scheme to couple trapped $^{87}$Rb atoms to a superconducting flux qubit through a magnetic dipole transition. We plan to trap atoms on the evanescent wave outside an ultrathin fiber to bring the atoms to less than 10 $\\mu$m above the surface of the superconductor. This hybrid setup lends itself to probing sources of decoherence in superconducting qubits. Our current plan has the intermediate goal of coupling the atoms to a superconducting LC resonator.

  15. Structural Description of Polyaromatic Nucleus in Residue

    Institute of Scientific and Technical Information of China (English)

    Zhang Huicheng; Yan Yongjie; Sun Wanfu; Wang Jifeng

    2007-01-01

    The proton nuclear magnetic resonance spectroscopy(1H-NMR),the synchronous fluorescence spectrometry(SFS)and the rutheniam ions catalyzed oxidation(RICO)method wen used to determine the chemical structure of polyaromatic nucleus in Oman residue fractions.The results of1H-NMR analyses showed that the average numbers of aromatic rings in the aromatics,resins and asphaltenes units were 3.2,5.6 and 8.2.respectively.SFS was used to investigate the distribution of aromatic tings in residue fractions,the main distribution range of aromatic rings in aromatics,resins and asphaltenes were 3-4 rings,3-5 rings and more than 5 tings,respectively.The aromatic network in residue fractions was oxidized to produce numerous carboxylic acids.The types and content of benzenepolycarboxylic acids,such as phthalic acid,benzenetricarboxylic acids,benzenetetracarbOxylic acids,benzenepentacarboxylic acid and benzenehexacarboxylic acid disclosed the condensed types of aromatic nuclei in the core.The biphenyl fraction(BIPH),the cata-condensed fraction(CATA),the peri-condensed fraction(PERI)and the condensed index(BCI)were calculated based on the benzenepolycarboxylic acids formed.The results implied that there was less biphenyl type structures in all residue fractions.The aromatics fraction was almost composed of the cata-condensed type system,and the asphaltenes fraction was wholly composed of the peri-condensed type system,while in the resins fraction co-existed the two types,herein the peri-condensed type Was predominant over the cata-condensed type.Based on the analytical results obtained in the study,the components-aromatics,resins and asphaltenes-were given the likely structural models.

  16. Inversion symmetry breaking of atomic bound states in strong and short laser fields

    CERN Document Server

    Stooß, Veit; Ott, Christian; Blättermann, Alexander; Ding, Thomas; Pfeifer, Thomas

    2015-01-01

    In any atomic species, the spherically symmetric potential originating from the charged nucleus results in fundamental symmetry properties governing the structure of atomic states and transition rules between them. If atoms are exposed to external electric fields, these properties are modified giving rise to energy shifts such as the AC Stark-effect in varying fields and, contrary to this in a constant (DC) electric field for high enough field strengths, the breaking of the atomic symmetry which causes fundamental changes in the atom's properties. This has already been observed for atomic Rydberg states with high principal quantum numbers. Here, we report on the observation of symmetry breaking effects in Helium atoms for states with principal quantum number n=2 utilizing strong visible laser fields. These findings were enabled by temporally resolving the dynamics better than the sub-optical cycle of the applied laser field, utilizing the method of attosecond transient absorption spectroscopy (ATAS). We ident...

  17. Experimental studies of pion-nucleus interactions at intermediate energies. [New Mexico State Univ. , Las Cruces, New Mexico

    Energy Technology Data Exchange (ETDEWEB)

    1992-12-31

    This report summarizes investigations of various pion-nucleus interactions and nucleon-nucleus charge-exchange reactions. The work was carried out with the LAMPF accelerator at the Los Alamos National Laboratory and the cyclotrons at the Paul Scherrer Institute (PSI) near Zurich, Switzerland, and at Indiana University (IUCF), as a collaborative effort among several laboratories and universities. The experimental activity at LAMPF involved measurements of new data on pion double-charge-exchange scattering, some initial work on a new Neutral Meson Spectrometer system, a search for deeply-bound pionic atoms, measurements of elastic scattering, and studies of the (n,p) reaction on various nuclei. At PSI measurements of pion quasielastic scattering were carried out, with detection of the recoil proton. Work on the analysis of data from a previous experiment at PSI on pion absorption in nuclei was continued. This experiment involved using a detector system that covered nearly the full solid angle.

  18. Higher-order corrections to electron-nucleus bremsstrahlung cross sections above a few MeV

    Science.gov (United States)

    Mangiarotti, A.; Martins, M. N.

    2016-08-01

    Despite the fact that the first calculations of nuclear bremsstrahlung cross sections were performed for relativistic electrons more than 80 years ago by Sauter, Bethe and Heitler, and Racah, a fully satisfactory solution to this problem is still missing up to the present day. Numerical approaches are impractical for electrons with energies above a few MeV because they require a prohibitively large number of partial waves. Analytic formulae need to describe simultaneously and accurately the interaction with the Coulomb field of the nucleus and the screening effect of the atomic electrons. In the present paper, a state-of-the-art analytic calculation will be discussed. In particular, higher-order corrections to the interaction with the Coulomb field of the nucleus, a subject seldom tackled in the past, are included and compared extensively with published data. The emerged difficulties will be highlighted, but unfortunately they can be overcome only with future large coordinated theoretical and experimental efforts.

  19. Atomic Spectra Database (ASD)

    Science.gov (United States)

    SRD 78 NIST Atomic Spectra Database (ASD) (Web, free access)   This database provides access and search capability for NIST critically evaluated data on atomic energy levels, wavelengths, and transition probabilities that are reasonably up-to-date. The NIST Atomic Spectroscopy Data Center has carried out these critical compilations.

  20. Proceedings of the workshop on fundamental muon physics: atoms, nuclei, and particles

    International Nuclear Information System (INIS)

    This report contains the proceedings of a workshop held at Los Alamos, January 20-22, 1986, to discuss present and future experiments with muons in particle, nuclear, and atomic physics. Special attention was paid to new developments in muon beams and detection devices. The workshop sessions were Muon Decay, Muon Capture, QED and Electroweak Interactions, Laser Spectroscopy of Muonic Atoms, High-Energy Muon-Nucleon and Muon-Nucleus Scattering, Muon Beams - New Developments, and Muon Catalysis

  1. Study of chemical equilibrium in nucleus-nucleus collisions at AGS and SPS energies

    CERN Document Server

    Becattini, F; Keränen, A; Manninen, J; Stock, Reinhard

    2003-01-01

    We present a detailed study of chemical freeze-out in nucleus-nucleus collisions at beam energies of 11.6, 30, 40, 80 and 158A GeV. By analyzing hadronic multiplicities within the statistical hadronization approach, we have studied the strangeness production as a function of centre of mass energy and of the parameters of the source. We have tested and compared different versions of the statistical model, with special emphasis on possible explanations of the observed strangeness hadronic phase space under-saturation. We show that, in this energy range, the use of hadron yields at midrapidity instead of in full phase space artificially enhances strangeness production and could lead to incorrect conclusions as far as the occurrence of full chemical equilibrium is concerned. In addition to the basic model with an extra strange quark non-equilibrium parameter, we have tested three more schemes: a two-component model superimposing hadrons coming out of single nucleon-nucleon interactions to those emerging from larg...

  2. Nuclear mean field and double-folding model of the nucleus-nucleus optical potential

    CERN Document Server

    Khoa, Dao T; Loan, Doan Thi; Loc, Bui Minh

    2016-01-01

    Realistic density dependent CDM3Yn versions of the M3Y interaction have been used in an extended Hartree-Fock (HF) calculation of nuclear matter (NM), with the nucleon single-particle potential determined from the total NM energy based on the Hugenholtz-van Hove theorem that gives rise naturally to a rearrangement term (RT). Using the RT of the single-nucleon potential obtained exactly at different NM densities, the density- and energy dependence of the CDM3Yn interactions was modified to account properly for both the RT and observed energy dependence of the nucleon optical potential. Based on a local density approximation, the double-folding model of the nucleus-nucleus optical potential has been extended to take into account consistently the rearrangement effect and energy dependence of the nuclear mean-field potential, using the modified CDM3Yn interactions. The extended double-folding model was applied to study the elastic $^{12}$C+$^{12}$C and $^{16}$O+$^{12}$C scattering at the refractive energies, wher...

  3. Electromagnetic probes of a pure-glue initial state in nucleus-nucleus collisions at LHC

    CERN Document Server

    Vovchenko, V; Gorenstein, M I; Satarov, L M; Mishustin, I N; Kämpfer, B; Stoecker, H

    2016-01-01

    Partonic matter produced in the early stage of ultrarelativistic nucleus-nucleus collisions is assumed to be composed mainly of gluons, and quarks and antiquarks are produced at later times. To study the implications of such a scenario, the dynamical evolution of the chemically nonequilibrated system is described by the ideal (2+1)-dimensional hydrodynamics with a time dependent (anti)quark fugacity. The equation of state interpolates linearly between the lattice data for the pure gluonic matter and the lattice data for the chemically equilibrated quark-gluon plasma. The spectra and elliptic flows of thermal dileptons and photons are calculated for central Pb+Pb collisions at the LHC energy of $\\sqrt{s_{_{\\rm NN}}} = 2.76$ TeV. We test the sensitivity of the results to the choice of equilibration times, including also the case where the complete chemical equilibrium of partons is reached already at the initial stage. It is shown that a suppression of quarks at early times leads to a significant reduction of t...

  4. Statistical Model of the Early Stage of nucleus-nucleus collisions with exact strangeness conservation

    CERN Document Server

    Poberezhnyuk, R V; Gorenstein, M I

    2015-01-01

    The Statistical Model of the Early Stage, SMES, describes a transition between confined and deconfined phases of strongly interacting matter created in nucleus-nucleus collisions. The model was formulated in the late 1990s for central Pb+Pb collisions at the CERN SPS energies. It predicted several signals of the transition (onset of deconfinement) which were later observed by the NA49 experiment. The grand canonical ensemble was used to calculate entropy and strangeness production. This approximation is valid for reactions with mean multiplicities of particles carrying conserved charges being significantly larger than one. Recent results of NA61/SHINE on hadron production in inelastic p+p interactions suggest that the deconfinement may also take place in these reactions. However, in this case mean multiplicity of particles with non-zero strange charge is smaller than one. Thus for the modeling of p+p interactions the exact strangeness conservation has to be implemented in the SMES. This extension of the SMES ...

  5. Relativistic transport approach for nucleus-nucleus collisions based on a NJL lagrangian

    CERN Document Server

    Ehehalt, W; Ehehalt, Wolfgang; Cassing, Wolfgang

    1995-01-01

    We formulate a covariant transport approach for high energy nucleus-nucleus collisions where the real part of the hadron selfenergies is evaluated on the basis of a NJL-type Lagrangian for the quark degrees of freedom. The parameters of the model Lagrangian are fixed by the Gell-Mann, Oakes and Renner relation, the pion-nucleon \\Sigma-term, the nucleon energy as well as the nuclear binding energy at saturation density \\rho_0. We find the resulting scalar and vector selfenergies for nucleons to be well in line with either Dirac-Brueckner results or those from the phenomenological optical potential when accounting for a swelling of the nucleon at finite nuclear matter density. The imaginary part of the hadron selfenergies is determined by a string fragmentation model which accounts for the in-medium mass of hadrons in line with the chiral dynamics employed. The applicability of the 'chiral' transport approach is demonstrated in comparison with experimental data from SIS to SPS energies. The enhancement of the K...

  6. EOS: A time projection chamber for the study of nucleus-nucleus collisions at the Bevalac

    Energy Technology Data Exchange (ETDEWEB)

    Pugh, H.G.; Odyniec, G.; Rai, G.; Seidl, P.

    1986-12-01

    The conceptual design is presented for a detector to identify and measure (..delta..p/p approx. = 1%) most of the 200 or so mid-rapidity charged particles (p, d, t, /sup 3/He, /sup 4/He, ..pi../sup + -/, K/sup + -/) produced in each central nucleus-nucleus collision (Au + Au) at Bevalac energies, as well as K/sub 3//sup 0/ and ..lambda../sup 0/. The beam particles and heavy spectator fragments are excluded from the detection volume by means of a central vacuum pipe. Particle identification is achieved by a combination of dE/dx measurements in the TPC, and of time-of-flight measurements in a scintillator array. The TPC is single-ended and its end cap is entirely covered with cathode pads (about 25,000 pads and about 1000 anode wires). A non-uniform pad distribution is proposed to accommodate the high multiplicity of particles emitted at forward angles. The performance of the detector is assessed with regard to multihit capability, tracking, momentum resolution, particle identification, ..lambda../sup 0/ reconstruction, space charge effects, field non-uniformity, dynamic range, data acquisition rate, and data analysis rate. 72 refs., 48 figs., 11 tabs.

  7. Energy-Dependence of Nucleus-Nucleus Potential and Friction Parameter in Fusion Reactions

    CERN Document Server

    Wen, Kai; Li, Zhu-Xia; Wu, Xi-Zhen; Zhang, Ying-Xun; Zhou, Shan-Gui

    2014-01-01

    Applying a macroscopic reduction procedure on the improved quantum molecular dynamics (ImQMD), the energy dependences of the nucleus-nucleus potential, the friction parameter, and the random force characterizing a one-dimensional Langevin-type description of the heavy-ion fusion process are investigated. Systematic calculations with the ImQMD show that the fluctuation-dissipation relation found in the symmetric head-on fusion reactions at energies just above the Coulomb barrier fades out when the incident energy increases. It turns out that this dynamical change with increasing incident energy is caused by a specific behavior of the friction parameter which directly depends on the microscopic dynamical process, i.e., on how the collective energy of the relative motion is transferred into the intrinsic excitation energy. It is shown microscopically that the energy dissipation in the fusion process is governed by two mechanisms: One is caused by the nucleon exchanges between two fusing nuclei, and the other is ...

  8. Semiclassical model for single-particle transitions in nucleus-nucleus interactions

    International Nuclear Information System (INIS)

    A previously elaborated semiclassical one-body model for the dynamics of a single particle, moving in two potentials, in heavy-ion reactions or in fissioning systems has been extended with respect to the inclusion of angular momenta and more realistic separable potentials. The collective relative motion is assumed to proceed along a trajectory which is calculated from classical equations of motion including conservative and phenomenological friction forces. The formalism has been derived involving three-dimensional trajectories for symmetric as well as for asymmetric nucleus-nucleus systems. The model allows for the calculation of correct quantum mechanical transition amplitudes to final bound and continuum states. It has been applied for the investigation of the excitation of a neutron during a fission process, covering also non-statistical differential emission probabilities. From the numerical calculations, using parameters adapted to 252Cf(sf), one can conclude that in the underlying model without 'sudden' processes the energy spectrum consists of two parts. The low lying component is created in the neck region while a high lying part seems to be governed mainly by the dynamics of the underlying collective motion rather than by the specific initial conditions. (orig.)

  9. Isotope Dependence of Superheavy Nucleus Formation Cross Section

    Institute of Scientific and Technical Information of China (English)

    LIU Zu-Hua; BAG Jing-Dong

    2006-01-01

    The dynamical process in the superheavy nucleus synthesis is studied on the basis of the two-dimensional Smolu-chowski equation. Special attention is paid to the isotope dependence of the cross section for the superheavy nucleus formation by means of making a comparison among the reaction systems of 54Fe + 204Pb, 56Fe + 206Pb, and 58Fe + 208Pb. It is found by this comparison that the formation cross section is very sensitive to the conditional saddle-point height and the neutron separation energy of the compound nucleus. Reaction systems with lower height of conditional saddle-point and smaller neutron separation energy are more favourable for the synthesis of the superheavy nucleus.

  10. Red nucleus connectivity as revealed by constrained spherical deconvolution tractography.

    Science.gov (United States)

    Milardi, Demetrio; Cacciola, Alberto; Cutroneo, Giuseppina; Marino, Silvia; Irrera, Mariangela; Cacciola, Giorgio; Santoro, Giuseppe; Ciolli, Pietro; Anastasi, Giuseppe; Calabrò, Rocco Salvatore; Quartarone, Angelo

    2016-07-28

    Previous Diffusion Tensor Imaging studies have demonstrated that the human red nucleus is widely interconnected with sensory-motor and prefrontal cortices. In this study, we assessed red nucleus connectivity by using a multi-tensor model called non- negative Constrained Spherical Deconvolution (CSD), which is able to resolve more than one fiber orientation per voxel. Connections of the red nuclei of fifteen volunteers were studied at 3T using CSD axonal tracking. We found significant connectivity between RN and the following cortical and subcortical areas: cerebellar cortex, thalamus, paracentral lobule, postcentral gyrus, precentral gyrus, superior frontal gyrus and dentate nucleus. We confirmed that red nucleus is tightly linked with the cerebral cortex and has dense subcortical connections with thalamus and cerebellar cortex. These findings may be useful in a clinical context considering that RN is involved in motor control and it is known to have potential to compensate for injury of the corticospinal tract. PMID:27181514

  11. Nucleus management in manual small incision cataract surgery by phacosection

    Directory of Open Access Journals (Sweden)

    Ravindra M

    2009-01-01

    Full Text Available Nucleus management is critical in manual small incision cataract surgery (MSICS, as the integrity of the tunnel, endothelium and posterior capsule needs to be respected. Several techniques of nucleus management are in vogue, depending upon the specific technique of MSICS. Nucleus can be removed in toto or bisected or trisected into smaller segments. The pressure in the eye can be maintained at the desired level with the use of an anterior chamber maintainer or kept at atmospheric levels. In MSICS, unlike phacoemulsification, there is no need to limit the size of the tunnel or restrain the size of capsulorrhexis. Large well-structured tunnels and larger capsulorrhexis provide better control on the surgical maneuvers. Safety and simplicity of MSICS has made it extremely popular. The purpose of this article is to describe nucleus management by phacosection in MSICS.

  12. Asymptotic properties of high-pT particle production in hadron-hadron, hadron-nucleus and nucleus-nucleus collisions at high energies

    CERN Document Server

    Tokarev, M V

    2001-01-01

    The concept of z-scaling reflecting the general features of particle substructure, constituent interaction and mechanism of particle formation is reviewed. Experimental data on the cross sections obtained at ISR, SpS and Tevatron are used in the analysis. The properties of data z-presentation, the energy and angular independencies, the power law, A- and F-dependencies, are discussed. The use of z-scaling to search for new physics phenomena in hadron-hadron, hadron-nucleus and nucleus-nucleus collisions is suggested. The violation of z-scaling characterized by the change of the fractal dimension is considered as a new and complimentary signature of nuclear phase transition.

  13. Neutral current neutrino-nucleus interactions at high energies

    CERN Document Server

    Ducati, M B Gay; Machado, M V T

    2008-01-01

    We present a QCD analysis of the neutral current neutrino-nucleus interaction at the small-x region using the color dipole formalism. This phenomenological approach is quite successful in describing experimental results in deep inelastic ep scattering and charged current neutrino-nucleus interactions at high energies. We present theoretical predictions for the relevant structure functions and the corresponding implications for the total NC neutrino cross section.

  14. The integrative role of the pedunculopontine nucleus in human gait.

    Science.gov (United States)

    Lau, Brian; Welter, Marie-Laure; Belaid, Hayat; Fernandez Vidal, Sara; Bardinet, Eric; Grabli, David; Karachi, Carine

    2015-05-01

    The brainstem pedunculopontine nucleus has a likely, although unclear, role in gait control, and is a potential deep brain stimulation target for treating resistant gait disorders. These disorders are a major therapeutic challenge for the ageing population, especially in Parkinson's disease where gait and balance disorders can become resistant to both dopaminergic medication and subthalamic nucleus stimulation. Here, we present electrophysiological evidence that the pedunculopontine and subthalamic nuclei are involved in distinct aspects of gait using a locomotor imagery task in 14 patients with Parkinson's disease undergoing surgery for the implantation of pedunculopontine or subthalamic nuclei deep brain stimulation electrodes. We performed electrophysiological recordings in two phases, once during surgery, and again several days after surgery in a subset of patients. The majority of pedunculopontine nucleus neurons (57%) recorded intrasurgically exhibited changes in activity related to different task components, with 29% modulated during visual stimulation, 41% modulated during voluntary hand movement, and 49% modulated during imaginary gait. Pedunculopontine nucleus local field potentials recorded post-surgically were modulated in the beta and gamma bands during visual and motor events, and we observed alpha and beta band synchronization that was sustained for the duration of imaginary gait and spatially localized within the pedunculopontine nucleus. In contrast, significantly fewer subthalamic nucleus neurons (27%) recorded intrasurgically were modulated during the locomotor imagery, with most increasing or decreasing activity phasically during the hand movement that initiated or terminated imaginary gait. Our data support the hypothesis that the pedunculopontine nucleus influences gait control in manners extending beyond simply driving pattern generation. In contrast, the subthalamic nucleus seems to control movement execution that is not likely to be gait

  15. Leading nucleon and the proton-nucleus inelasticity

    CERN Document Server

    Bellandi, J; Dias de Deus, J

    1999-01-01

    We present in this paper a calculation of the average proton-nucleus inelasticity. Using an Iterative Leading Particle Model and the Glauber model, we relate the leading particle distribution in nucleon-nucleus interactions with the respective one in nucleon- proton collisions. To describe the leading particle distribution in nucleon-proton collisions, we use the Regge Mueller formalism. Contribution to 26th ICRC - Salt Lake City, Utah. August, 1999. HE 1.1.14

  16. New computational methods for determining antikaon-nucleus bound states

    International Nuclear Information System (INIS)

    Optical potential for antikaon-nucleus strong interactions are constructed using elementary antikaon-nucleus potentials determined previously. The optical potentials are used to determine the existence of a kaon hypernucleus. Modern three dimensional visualization techniques are used to study model dependences, new methods for speeding the calculation of the optical potential are developed, and previous approximation to avoid full Fermi averaging are eliminated. 19 refs., 21 figs., 3 tabs

  17. Inelaticity in hadron-nucleus collisions from emulsion chamber studies

    CERN Document Server

    Wilk, G

    1999-01-01

    The inelasticity of hadron-carbon nucleus collisions in the energy region exceeding 100 TeV is estimated from the carbon-emulsion chamber data at Pamirs to be $ = 0.65\\pm 0.08$. When combined with the recently presented data on hadron-lead nucleus collisions taken at the same energy range it results in the $K\\sim A^{0.086}$ mass number dependence of inelasticity. The evaluated partial inelasticity for secondary ($\

  18. Nucleus Pearl Coating Process of Freshwater Mussel Anodonta woodiana (Unionidae)

    OpenAIRE

    WASMEN MANALU; DEDY DURYADI SOLIHIN; SATA YOSHIDA SRIE RAHAYU; RIDWAN AFFANDI

    2013-01-01

    The limiting factor which is a weakness of sea water pearl production are high costs, the risk of major business failures and a long coating time. From the issue of freshwater pearls appear to have prospects of alternative substitution for sea water pearl. This present study aimed to evaluate effect of loads (the number and diameter nucleus) on freshwater pearl coating process and the number and size of the appropriate nucleus diameter, to produce the optimum coating thickness of half-round p...

  19. Specific structure of the 6He nucleus and fragmentation experiments

    International Nuclear Information System (INIS)

    Within the framework of the microscopic α+2n model, transverse momentum distributions of α-particles and neutrons as well as α-particle - neutron momentum correlation function have been calculated for the radioactive 6He nucleus fragmentation. The results show that these momentum distributions reflect a specific structure of the 6He nucleus, i.e. the experiments on fragmentation provide with the information on 6He structure. (orig.)

  20. Shell Correction at the Saddle Point for Superheavy Nucleus

    Institute of Scientific and Technical Information of China (English)

    张炜; 张时声; 张双全; 孟杰

    2003-01-01

    The potential energy surface for superheavy nucleus has been studied within the framework of the constrained relativistic mean field theory, and the shell correction energy as a function of deformation has been extracted by the Strutinsky shell correction procedure. Contrary to the usual expectation, the shell correction energy at the saddle point is too important to be neglected, and it has essential contribution to the fission barrier in superheavy nucleus.

  1. Existence of a ground state for the confined hydrogen atom in non-relativistic QED

    DEFF Research Database (Denmark)

    Amour, Laurent; Faupin, Jeremy

    2008-01-01

    We consider a system of a hydrogen atom interacting with the quantized electromagnetic field. Instead of fixing the nucleus, we assume that the system is confined by its center of mass. This model is used in theoretical physics to explain the Lamb-Dicke effect. After a brief review of the...

  2. Probing the compressibility of tumor cell nuclei by combined atomic force-confocal microscopy

    NARCIS (Netherlands)

    Krause, M.; Riet, J. te; Wolf, K. van der

    2013-01-01

    The cell nucleus is the largest and stiffest organelle rendering it the limiting compartment during migration of invasive tumor cells through dense connective tissue. We here describe a combined atomic force microscopy (AFM)-confocal microscopy approach for measurement of bulk nuclear stiffness toge

  3. Electric-field gradients used to measure atomic short range order: as a case-study

    Science.gov (United States)

    Cottenier, S.; Meersschaut, J.; Vermeire, L.; Demuynck, S.; Swinnen, B.; Rots, M.

    1999-02-01

    A scheme is presented in order to obtain complete information on atomic short range order in crystalline materials based on measuring the electric-field gradient on a probe nucleus. Limitations and possible improvements of the method are discussed. When applied to U(In0.5Sn0.5)3, short range order with In-Sn attraction is found.

  4. Single Atom Plasmonic Switch

    CERN Document Server

    Emboras, Alexandros; Ma, Ping; Haffner, Christian; Luisier, Mathieu; Hafner, Christian; Schimmel, Thomas; Leuthold, Juerg

    2015-01-01

    The atom sets an ultimate scaling limit to Moores law in the electronics industry. And while electronics research already explores atomic scales devices, photonics research still deals with devices at the micrometer scale. Here we demonstrate that photonic scaling-similar to electronics-is only limited by the atom. More precisely, we introduce an electrically controlled single atom plasmonic switch. The switch allows for fast and reproducible switching by means of the relocation of an individual or at most - a few atoms in a plasmonic cavity. Depending on the location of the atom either of two distinct plasmonic cavity resonance states are supported. Experimental results show reversible digital optical switching with an extinction ration of 10 dB and operation at room temperature with femtojoule (fJ) power consumption for a single switch operation. This demonstration of a CMOS compatible, integrated quantum device allowing to control photons at the single-atom level opens intriguing perspectives for a fully i...

  5. Interferometry with atoms

    International Nuclear Information System (INIS)

    Optics and interferometry with matter waves is the art of coherently manipulating the translational motion of particles like neutrons, atoms and molecules. Coherent atom optics is an extension of techniques that were developed for manipulating internal quantum states. Applying these ideas to translational motion required the development of techniques to localize atoms and transfer population coherently between distant localities. In this view position and momentum are (continuous) quantum mechanical degrees of freedom analogous to discrete internal quantum states. In our contribution we start with an introduction into matter wave optics in sect. 1, discuss coherent atom optics and atom interferometry techniques for molecular beams in sect. 2 and for trapped atoms in sect. 3. In sect. 4 we then describe tools and experiments that allow to probe the evolution of quantum states of many-body systems by atom interference.

  6. A Universal Description of Pseudorapidity Distributions in Both Nucleus-Nucleus and p-p Collisions at Currently Available Energies

    Directory of Open Access Journals (Sweden)

    Z. J. Jiang

    2016-01-01

    Full Text Available Investigations have shown that the collective motion appears not only in nucleus-nucleus but also in p-p collisions. The best tool for depicting such collective motion is relativistic hydrodynamics. In this paper, the collective motion is assumed to obey the hydrodynamic model which integrates the features of Landau and Hwa-Bjorken theory and is one of a very few analytically solvable models. The fluid is then supposed to freeze out into charged particles from a space-like hypersurface with a fixed time of tFO. The investigations of present paper show that this part of charged particles together with leading particles, which, by conventional definition, carry on the quantum numbers of colliding nucleons and take away the most part of incident energy, can give a proper universal description to the pseudorapidity distributions of charged particles measured in both nucleus-nucleus and p-p collisions at currently available energies.

  7. ELECTROPHYSIOLOGICAL PROPERTIES OF MORPHOLOGICALLY-IDENTIFIED MEDIAL VESTIBULAR NUCLEUS NEURONS PROJECTING TO THE ABDUCENS NUCLEUS IN THE CHICK EMBRYO

    OpenAIRE

    Gottesman-Davis, Adria; Shao, Mei; Hirsch, June C.; Peusner, Kenna D.

    2010-01-01

    Neurons in the medial vestibular nucleus (MVN) show a wide range of axonal projection pathways, intrinsic firing properties, and responses to head movements. To determine whether MVN neurons participating in the vestibulocular reflexes (VOR) have distinctive electrophysiological properties related to their output pathways, a new preparation was devised using transverse brain slices containing the chicken MVN and abducens nucleus. Biocytin Alexa Fluor was injected extracellularly into the abdu...

  8. The deafferented reticular thalamic nucleus generates spindle rhythmicity.

    Science.gov (United States)

    Steriade, M; Domich, L; Oakson, G; Deschênes, M

    1987-01-01

    The hypothesis that nucleus reticularis thalami (RE) is the generator of spindle rhythmicity during electroencephalogram (EEG) synchronization was tested in acutely prepared cats. Unit discharges and focal waves were extracellularly recorded in the rostral pole of RE nucleus, which was completely disconnected by transections from all other thalamic nuclei. In some experiments, additional transections through corona radiata created a triangular island in which the rostral RE pole survived with the caudate nucleus, putamen, basal forebrain nuclei, prepyriform area, and the adjacent cortex. Similar results were obtained in two types of experiments: brain stem-transected preparations that exhibited spontaneous spindle sequences, and animals under ketamine anesthesia in which transient spindling was repeatedly precipitated during recording by very low doses of a short-acting barbiturate. Both spindle-related rhythms (7- to 16-Hz waves grouped in sequences that recur with a rhythm of 0.1-0.3 Hz) are seen in focal recordings of the deafferented RE nucleus. The presence of spindling rhythmicity in the disconnected RE nucleus contrasts with total absence of spindles in cortical EEG leads and in thalamic recordings behind the transection. Oscillations within the same frequency range as that of spontaneous spindles can be evoked in the deafferented RE nucleus by subcortical white matter stimulation. In deafferented RE cells, the burst structure consists of an initially biphasic acceleration-deceleration pattern, eventually leading to a long-lasting tonic tail. Quantitative group data show that the burst parameters of disconnected RE cells are very similar to those of RE neurons with intact connections. In the deafferented RE nucleus, spike bursts of RE neurons recur periodically (0.1-0.3 Hz) in close time-relation with simultaneously recorded focal spindle sequences. The burst occurrence of deafferented RE cells is greatly reduced after systemic administration of bicuculline

  9. On the Role of the Transition State Nucleus in Fission

    International Nuclear Information System (INIS)

    Although it is well-known that times. In order for fission to compete favourably with gamma-ray and neutron emission, a fixed amount of energy, equivalent to an activation energy in a chemical reaction, must be supplied to the heavy nucleus. This energy (often referred to as the fission threshold) is approximately 5 to 6 MeV for U238, and is the minimum energy required to produce the deformed transition state nucleus (zero internal excitation energy). In the process of stretching the original nucleus into the transition state nucleus (whose distortion is sometimes described as the saddle-point deformation), the increase in energy due to the short-range nuclear forces (surface tension) is greater than the decrease in energy due to the long-range Coulomb forces. However, as the particular distortion defining the transition state nucleus is approached, the decrease in Coulomb energy becomes equal to the increase in surface energy. The degree of distortion needed to produce the transition state nucleus is a function of several nuclear parameters and, hence, the saddle shape and threshold energy for fission change markedly for different nuclei. Since a large fraction of the excitation energy of the initial compound nucleus is consumed in deformation energy in passing to the fission saddle point, the transition state nucleus is thermodynamically ''cold''. Hence, for low excitation energies where the non-fission degrees of freedom favour the passage of the barrier with only a small kinetic energy, it seems reasonable to postulate that the traversal time of the saddle or the lifetime of the transition state nucleus is many orders of magnitude longer than the characteristic nuclear time. This leads to the prediction that the highly deformed transition state nucleus will have properties, including a spectrum of excited states, analogous to those of normal nuclei. Information on highly deformed transition state nuclei obtained by fission-fragment angular distribution studies

  10. Preparation and Characterization of Nucleus/Shell TiO2/HAP Complex Nanophotocatalyst

    Institute of Scientific and Technical Information of China (English)

    Hongfei LIU; Xiaonong CHENG; Juan YANG; Xuehua YAN; Hebin SHI

    2007-01-01

    A rapid and more efficient method was developed to prepare nucleus/shell titania/hydroxyapatite (TiO2/HAP)complex nanophotocatalyst. Hydroxyapatite (5μm) which had been dissolved with 0.1 mol/L HCI was formed on the surface of the nanosized anatase titania powders by increasing the pH value of the solution at 90℃ in the water bath for only several hours .The microstructure and morphology of the resulting sample were investigated by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy dispersive spectrum (EDS) and atomic force microscope (AFM). The results indicated that nucleus/shell structural TiO2/HAP was formed in our experiments, and the thickness of the coating layer was about 5 nm. Photocatalytic decomposition of methyl orange was utilized to test the photocatalysis of the resulting samples and the result was compared with that of pure anatase titania powders (about 20 nm). It was shown that the photocatalytic activity of the sample was not decreased due to the coating of HAP.

  11. Extreme ground-state deformation of the N = Z nucleus 76Sr

    Science.gov (United States)

    Lemasson, A.; Iwasaki, H.; Morse, C.; Baugher, T.; Bazin, D.; Berryman, J.; Gade, A.; McDaniel, S.; Ratkiewicz, A.; Stroberg, S.; Weisshaar, D.; Wimmer, K.; Winkler, R.; Dewald, A.; Fransen, C.; Nichols, A.; Wadsworth, R.

    2011-10-01

    The shape of the atomic nucleus is determined by the interplay of macroscopic and microscopic effects within this quantum mechanical many-body system. Self-conjugate nuclei give an opportunity to study the role of np correlations in deformation and have attracted a great interest due to drastic shape evolution along the N = Z line. Strong ground-state deformation is expected to occur for N = Z nuclei above Z = 36 from the 2+ energy systematic as well as from theoretical predictions. Reduced transition strengths B(E2) can guide our understanding of the onset of collectivity along N = Z line. Here, we report on the first determination of B(E2; 2+ -->0+) for the N = Z = 38 nucleus 76Sr obtained from the measurement of the 2+ state lifetime using a line shape technique. 76Sr nuclei were produced at the NSCL in charge exchange reaction from fast secondary 76Rb beam. γ-rays emitted at the reaction target position were measured with the SeGA HPGe array in coincidence with reaction residues detected in the S800 spectrometer. Results will be discussed in the light of available data and theoretical predictions to provide insight into the evolution of shell structure and deformation in this region.

  12. Fluctuations and correlations in nucleus-nucleus collisions within transport approaches

    Energy Technology Data Exchange (ETDEWEB)

    Konchakovski, Volodymyr P.

    2009-10-01

    The current thesis is devoted to a systematic study of fluctuations and correlations in heavy-ion collisions, which might be considered as probes for the phase transition and the critical point in the phase diagram, within the Hadron-String- Dynamics (HSD) microscopic transport approach. This is a powerful tool to study nucleus-nucleus collisions and allows to completely simulate experimental collisions on an event-by-event basis. Thus, the transport model has been used to study fluctuations and correlations including the influence of experimental acceptance as well as centrality, system size and collision energy. The comparison to experimental data can separate the effects induced by a phase transition since there is no phase transition in the HSD version used here. Firstly the centrality dependence of multiplicity fluctuations has been studied. Different centrality selections have been performed in the analysis in correspondence to the experimental situation. For the fixed target experiment NA49 events with fixed numbers of the projectile participants have been studied while in the collider experiment PHENIX centrality classes of events have been defined by the multiplicity in certain phase space region. A decrease of participant number fluctuations (and thus volume fluctuations) in more central collisions for both experiments has been obtained. Another area of this work addresses to transport model calculations of multiplicity fluctuations in nucleus-nucleus collisions as a function of colliding energy and system size. This study is in full correspondence to the experimental program of the NA61 Collaboration at the SPS. Central C+C, S+S, In+In, and Pb+Pb nuclear collisions at Elab = 10, 20, 30, 40, 80, 158 AGeV have been investigated. The expected enhanced fluctuations - attributed to the critical point and phase transition - can be observed experimentally on top of a monotonic and smooth 'hadronic background'. These findings should be helpful for the

  13. Fluctuations and correlations in nucleus-nucleus collisions within transport approaches

    International Nuclear Information System (INIS)

    The current thesis is devoted to a systematic study of fluctuations and correlations in heavy-ion collisions, which might be considered as probes for the phase transition and the critical point in the phase diagram, within the Hadron-String- Dynamics (HSD) microscopic transport approach. This is a powerful tool to study nucleus-nucleus collisions and allows to completely simulate experimental collisions on an event-by-event basis. Thus, the transport model has been used to study fluctuations and correlations including the influence of experimental acceptance as well as centrality, system size and collision energy. The comparison to experimental data can separate the effects induced by a phase transition since there is no phase transition in the HSD version used here. Firstly the centrality dependence of multiplicity fluctuations has been studied. Different centrality selections have been performed in the analysis in correspondence to the experimental situation. For the fixed target experiment NA49 events with fixed numbers of the projectile participants have been studied while in the collider experiment PHENIX centrality classes of events have been defined by the multiplicity in certain phase space region. A decrease of participant number fluctuations (and thus volume fluctuations) in more central collisions for both experiments has been obtained. Another area of this work addresses to transport model calculations of multiplicity fluctuations in nucleus-nucleus collisions as a function of colliding energy and system size. This study is in full correspondence to the experimental program of the NA61 Collaboration at the SPS. Central C+C, S+S, In+In, and Pb+Pb nuclear collisions at Elab = 10, 20, 30, 40, 80, 158 AGeV have been investigated. The expected enhanced fluctuations - attributed to the critical point and phase transition - can be observed experimentally on top of a monotonic and smooth 'hadronic background'. These findings should be helpful for the optimal

  14. Modeling neutrino-nucleus interactions in the few-GeV regime

    CERN Document Server

    Jachowicz, Natalie

    2011-01-01

    Detecting neutrinos and extracting the information they bring along is an ambitions task that requires a detailed understanding of neutrino-nucleus interactions over a broad energy range. We present calculations for quasi-elastic neutrino-induced nucleon knockout reactions on atomic nuclei and neutrino-induced pion production reactions. In our models, final-state interactions are introduced using a relativistic multiple-scattering Glauber approximation (RMSGA) approach. For interactions at low incoming neutrino energies, long-range correlations are implemented by means of a continuum random phase approximation (CRPA) approach. As neutrinos are the only particles interacting solely by means of the weak interaction, they can reveal information about e.g. the structure of nuclei or the strange quark content of the nucleon that is difficult to obtain otherwise. We investigated these effects and present results for the sensitivity of neutrino interactions to the influence of the nucleon's strange quark sea.

  15. Chaotic behavior of the Compound Nucleus, open Quantum Dots and other nanostructures

    Directory of Open Access Journals (Sweden)

    Hussein M. S.

    2014-04-01

    Full Text Available It is well established that physical systems exhibit both ordered and chaotic behavior. The chaotic behavior of nanostructures such as open quantum dots has been confirmed experimentally and discussed exhaustively theoretically. This is manifested through random fluctuations in the electronic conductance. What useful information can be extracted from this noise in the conductance? In this contribution we shall address this question. In particular, we will show that the average maxima density in the conductance is directly related to the correlation function whose characteristic width is a measure of the energy- or applied magnetic field- correlation length. The idea behind the above was originally discovered in the context of the atomic nucleus, a mesoscopic system. Our findings are directly applicable to graphene.

  16. Manifestation of Universality in the Asymmetric Helium Trimer and in the Halo Nucleus $^{22}$C

    CERN Document Server

    Gridnev, Dmitry K

    2016-01-01

    We prove that the corner angle distributions in the bound three-body system AAB, which consists of two particles of type A and one particle of type B, approach universal form if the pair AA has a virtual state at zero energy and the binding energy of AAB goes to zero. We derive explicit expressions for the universal corner angle distributions in terms of elementary functions, which depend solely on the mass ratio m(A)/m(B) and do not depend on pair interactions. On the basis of experimental data and calculations we demonstrate that such systems as the asymmetric Helium trimer $^3$He$^4$He$_2$ and the halo nucleus $^{22}$C exhibit universal features. Thus our result establishes an interesting link between atomic and nuclear physics through the few-body universality.

  17. Primakoff production of $\\pi^0$, $\\eta$ and $\\eta'$ in the Coulomb field of a nucleus

    CERN Document Server

    Kaskulov, Murat M

    2011-01-01

    Photoproduction of neutral pseudoscalar mesons $\\pi^0,\\eta(547)$ and $\\eta'(958)$ in the Coulomb field of an atomic nucleus is studied using a model which describes the Primakoff and nuclear parts of the production amplitude. At high energies the nuclear background is dominated by the exchange of $C$-parity odd Regge trajectories. In the coherent production the isospin filtering makes the $\\omega(782)$ a dominant trajectory. The calculations are in agreement with $\\pi^0$ data from JLAB provided the photon shadowing and final state interactions of mesons are taken into account. The kinematic conditions which allow to study the Primakoff effect in $\\eta$ and $\\eta'$ photoproduction off nuclei are further discussed. We also give predictions for the higher energies available at the JLAB upgrade.

  18. Primakoff production of π0, η, and η' in the Coulomb field of a nucleus

    International Nuclear Information System (INIS)

    Photoproduction of neutral pseudoscalar mesons π0,η(547), and η'(958) in the Coulomb field of an atomic nucleus is studied using a model which describes the Primakoff and nuclear parts of the production amplitude. At high energies the nuclear background is dominated by the exchange of C-parity odd Regge trajectories. In the coherent production the isospin filtering makes the ω(782) a dominant trajectory. The calculations are in agreement with π0 data from JLAB provided the photon shadowing and final state interactions of mesons are taken into account. The kinematic conditions which allow to study the Primakoff effect in η and η' photoproduction off nuclei are further discussed. We also give predictions for the higher energies available at the JLAB upgrade.

  19. Primakoff production of π0, η and η' in the Coulomb field of a nucleus

    International Nuclear Information System (INIS)

    The Primakoff production of neutral pseudoscalar mesons π0, η(587) and η'(958) in the Coulomb field of an atomic nucleus is studied using a model which describes the coherent electromagnetic and nuclear parts of the production amplitude. At high energies the nuclear background is dominated by the exchange of C-parity odd Regge trajectories. In the coherent production the isospin filtering makes the ω(782) a dominant trajectory. We revise the production of pions which has been used to measure the π0→γγ decay width at JLAB. The calculations are in agreement with data provided the photon shadowing and final state interactions of mesons are taken into account. The kinematic conditions which allow to study the Primakoff effect in η and η' photoproduction off nuclei are further discussed.

  20. Long range intermolecular forces in triatomic systems: connecting the atom-diatom and atom-atom-atom representations

    OpenAIRE

    Cvitas, Marko T.; Soldan, Pavel; Hutson, Jeremy M.

    2005-01-01

    The long-range forces that act between three atoms are analysed in both atom-diatom and atom-atom-atom representations. Expressions for atom-diatom dispersion coefficients are obtained in terms of 3-body nonadditive coefficients. The anisotropy of atom-diatom C_6 dispersion coefficients arises primarily from nonadditive triple-dipole and quadruple-dipole forces, while pairwise-additive forces and nonadditive triple-dipole and dipole-dipole-quadrupole forces contribute significantly to atom-di...

  1. PREFACE: 11th International Conference on Nucleus-Nucleus Collisions (NN2012)

    Science.gov (United States)

    Li, Bao-An; Natowitz, Joseph B.

    2013-03-01

    The 11th International Conference on Nucleus-Nucleus Collisions (NN2012) was held from 27 May to 1 June 2012, in San Antonio, Texas, USA. It was jointly organized and hosted by The Cyclotron Institute at Texas A&M University, College Station and The Department of Physics and Astronomy at Texas A&M University-Commerce. Among the approximately 300 participants were a large number of graduate students and post-doctoral fellows. The Keynote Talk of the conference, 'The State of Affairs of Present and Future Nucleus-Nucleus Collision Science', was given by Dr Robert Tribble, University Distinguished Professor and Director of the TAMU Cyclotron Institute. During the conference a very well-received public lecture on neutrino astronomy, 'The ICEcube project', was given by Dr Francis Halzen, Hilldale and Gregory Breit Distinguished Professor at the University of Wisconsin, Madison. The Scientific program continued in the general spirit and intention of this conference series. As is typical of this conference a broad range of topics including fundamental areas of nuclear dynamics, structure, and applications were addressed in 42 plenary session talks, 150 parallel session talks, and 21 posters. The high quality of the work presented emphasized the vitality and relevance of the subject matter of this conference. Following the tradition, the NN2012 International Advisory Committee selected the host and site of the next conference in this series. The 12th International Conference on Nucleus-Nucleus Collisions (NN2015) will be held 21-26 June 2015 in Catania, Italy. It will be hosted by The INFN, Laboratori Nazionali del Sud, INFN, Catania and the Dipartimento di Fisica e Astronomia of the University of Catania. The NN2012 Proceedings contains the conference program and 165 articles organized into the following 10 sections 1. Heavy and Superheavy Elements 2. QCD and Hadron Physics 3. Relativistic Heavy-Ion Collisions 4. Nuclear Structure 5. Nuclear Energy and Applications of

  2. Single atom microscopy.

    Science.gov (United States)

    Zhou, Wu; Oxley, Mark P; Lupini, Andrew R; Krivanek, Ondrej L; Pennycook, Stephen J; Idrobo, Juan-Carlos

    2012-12-01

    We show that aberration-corrected scanning transmission electron microscopy operating at low accelerating voltages is able to analyze, simultaneously and with single atom resolution and sensitivity, the local atomic configuration, chemical identities, and optical response at point defect sites in monolayer graphene. Sequential fast-scan annular dark-field (ADF) imaging provides direct visualization of point defect diffusion within the graphene lattice, with all atoms clearly resolved and identified via quantitative image analysis. Summing multiple ADF frames of stationary defects produce images with minimized statistical noise and reduced distortions of atomic positions. Electron energy-loss spectrum imaging of single atoms allows the delocalization of inelastic scattering to be quantified, and full quantum mechanical calculations are able to describe the delocalization effect with good accuracy. These capabilities open new opportunities to probe the defect structure, defect dynamics, and local optical properties in 2D materials with single atom sensitivity. PMID:23146658

  3. Hypertrophic degeneration of the inferior olivary nucleus impacts perception of gravity

    Directory of Open Access Journals (Sweden)

    Alexander A Tarnutzer

    2012-05-01

    Full Text Available Interruption of the Guillain-Mollaret triangle interconnecting the red nucleus, the inferior olivary nucleus and the contralateral dentate nucleus is predicted to interfere with the dentate nucleus’ role in estimating direction of gravity. In a patient with pendular nystagmus due to hypertrophic inferior olivary nucleus degeneration secondary to ponto-mesencephalic hemorrhage, perceived vertical shifted from clockwise to counter-clockwise deviations within 4 months. We hypothesize that synchronized oscillations of inferior olivary nucleus neurons induce a loss of inhibitory control, leading to hyperactivity of the contralateral dentate nucleus and, as a result, to perceived vertical roll-tilt to the side of the overactive dentate nucleus.

  4. Atomic homodyne detection of weak atomic transitions.

    Science.gov (United States)

    Gunawardena, Mevan; Elliott, D S

    2007-01-26

    We have developed a two-color, two-pathway coherent control technique to detect and measure weak optical transitions in atoms by coherently beating the transition amplitude for the weak transition with that of a much stronger transition. We demonstrate the technique in atomic cesium, exciting the 6s(2)S(1/2) --> 8s(2)S(1/2) transition via a strong two-photon transition and a weak controllable Stark-induced transition. We discuss the enhancement in the signal-to-noise ratio for this measurement technique over that of direct detection of the weak transition rate, and project future refinements that may further improve its sensitivity and application to the measurement of other weak atomic interactions.

  5. Metal atom oxidation laser

    International Nuclear Information System (INIS)

    A chemical laser which operates by formation of metal or carbon atoms and reaction of such atoms with a gaseous oxidizer in an optical resonant cavity is described. The lasing species are diatomic or polyatomic in nature and are readily produced by exchange or other abstraction reactions between the metal or carbon atoms and the oxidizer. The lasing molecules may be metal or carbon monohalides or monoxides

  6. Advances in atomic physics

    Directory of Open Access Journals (Sweden)

    Tharwat M. El-Sherbini

    2015-09-01

    Full Text Available In this review article, important developments in the field of atomic physics are highlighted and linked to research works the author was involved in himself as a leader of the Cairo University – Atomic Physics Group. Starting from the late 1960s – when the author first engaged in research – an overview is provided of the milestones in the fascinating landscape of atomic physics.

  7. Advances in atomic physics

    OpenAIRE

    Tharwat M. El-Sherbini

    2015-01-01

    Graphical abstract In this review article, important developments in the field of atomic physics are highlighted and linked to research works the author was involved in himself as a leader of the Cairo University – Atomic Physics Group. Starting from the late 1960s – when the author first engaged in research - an overview is provided of the milestones in the fascinating landscape of atomic physics.

  8. Atomic and Molecular Physics

    OpenAIRE

    Cohen-Tannoudji, Claude

    2015-01-01

    When physicists began to explore the world of atoms more precisely, as they endeavoured to understand its structure and the laws governing its behaviour, they soon encountered serious difficulties. Our intuitive concepts, based on our daily experience of the macroscopic world around us, proved to be completely erroneous on the atomic scale; the atom was incomprehensible within the framework of classical physics. In order to uncover these new mysteries, after a great deal of trial and error, e...

  9. Advances in atomic spectroscopy

    CERN Document Server

    Sneddon, J

    1997-01-01

    This series describes selected advances in the area of atomic spectroscopy. It is primarily intended for the reader who has a background in atmoic spectroscopy; suitable to the novice and expert. Although a widely used and accepted method for metal and non-metal analysis in a variety of complex samples, Advances in Atomic Spectroscopy covers a wide range of materials. Each Chapter will completely cover an area of atomic spectroscopy where rapid development has occurred.

  10. Advances in atomic spectroscopy

    CERN Document Server

    Sneddon, J

    1995-01-01

    This series describes selected advances in the area of atomic spectroscopy. It is promarily intended for the reader who has a background in atmoic spectroscopy; suitable to the novice and expert. Although a widely used and accepted method for metal and non-metal analysis in a variety of complex samples, Advances in Atomic Spectroscopy covers a wide range of materials. Each Chapter will completely cover an area of atomic spectroscopy where rapid development has occurred.

  11. Metal atom oxidation laser

    Science.gov (United States)

    Jensen, R.J.; Rice, W.W.; Beattie, W.H.

    1975-10-28

    A chemical laser which operates by formation of metal or carbon atoms and reaction of such atoms with a gaseous oxidizer in an optical resonant cavity is described. The lasing species are diatomic or polyatomic in nature and are readily produced by exchange or other abstraction reactions between the metal or carbon atoms and the oxidizer. The lasing molecules may be metal or carbon monohalides or monoxides. (auth)

  12. Atomic Oxygen Effects

    Science.gov (United States)

    Miller, Sharon K. R.

    2014-01-01

    Atomic oxygen, which is the most predominant species in low Earth orbit, is highly reactive and can break chemical bonds on the surface of a wide variety of materials leading to volatilization or surface oxidation which can result in failure of spacecraft materials and components. This presentation will give an overview of how atomic oxygen reacts with spacecraft materials, results of space exposure testing of a variety of materials, and examples of failures caused by atomic oxygen.

  13. The Software Atom

    CERN Document Server

    Javanainen, Juha

    2016-01-01

    By putting together an abstract view on quantum mechanics and a quantum-optics picture of the interactions of an atom with light, we develop a corresponding set of C++ classes that set up the numerical analysis of an atom with an arbitrary set of angular-momentum degenerate energy levels, arbitrary light fields, and an applied magnetic field. As an example, we develop and implement perturbation theory to compute the polarizability of an atom in an experimentally relevant situation.

  14. Ionization of Atoms by Slow Heavy Particles, Including Dark Matter.

    Science.gov (United States)

    Roberts, B M; Flambaum, V V; Gribakin, G F

    2016-01-15

    Atoms and molecules can become ionized during the scattering of a slow, heavy particle off a bound electron. Such an interaction involving leptophilic weakly interacting massive particles (WIMPs) is a promising possible explanation for the anomalous 9σ annual modulation in the DAMA dark matter direct detection experiment [R. Bernabei et al., Eur. Phys. J. C 73, 2648 (2013)]. We demonstrate the applicability of the Born approximation for such an interaction by showing its equivalence to the semiclassical adiabatic treatment of atomic ionization by slow-moving WIMPs. Conventional wisdom has it that the ionization probability for such a process should be exponentially small. We show, however, that due to nonanalytic, cusplike behavior of Coulomb functions close to the nucleus this suppression is removed, leading to an effective atomic structure enhancement. We also show that electron relativistic effects actually give the dominant contribution to such a process, enhancing the differential cross section by up to 1000 times.

  15. Atomic spectroscopy introduction to the theory of hyperfine structure

    CERN Document Server

    Andreev, Anatoli V

    2006-01-01

    Atomic Spectroscopy provides a comprehensive discussion on the general approach to the theory of atomic spectra, based on the use of the Lagrangian canonical formalism. This approach is developed and applied to explain the hydrogenic hyperfine structure associated with the nucleus motion, its finite mass, and spin. The non-relativistic or relativistic, spin or spin-free particle approximations can be used as a starting point of general approach. The special attention is paid to the theory of Lamb shift formation. The formulae for hydrogenic spectrum including the account of Lamb shift are written in simple analytical form. The book is of interest to specialists, graduate and postgraduate students, who are involved into the experimental and theoretical research in the field of modern atomic spectroscopy.

  16. Optical dipole trapping of radium atoms for EDM search

    Science.gov (United States)

    Trimble, W. L.; Sulai, I. A.; Parker, R. H.; Bailey, K.; Greene, J. P.; Holt, R. J.; Korsch, W.; Lu, Z.-T.; Mueller, P.; O'Connor, T. P.; Singh, J.

    2010-03-01

    We are developing an EDM search based on laser-cooled and trapped Ra-225 (half-life = 15 d) atoms. Due to octupole deformation of the nucleus, Ra-225 is predicted to be 2-3 orders of magnitude more sensitive to T-violating interactions than Hg-199, which currently sets the most stringent limits in the nuclear sector. Recently, we have succeeded in transferring Ra-226 atoms from a MOT into an optical dipole trap formed by a fiber laser beam at 1550 nm. For the EDM measurement, the cold atoms will be moved into the neighboring vacuum chamber inside magnetic shields where a pair of electrodes apply a 10 kV cm-1electric field. This work is supported by DOE, Office of Nuclear Physics under contract No. DE-AC02-06CH11357.

  17. Harmonic oscillator model for the helium atom

    CERN Document Server

    Carlsen, Martin

    2015-01-01

    A harmonic oscillator model in four dimensions is presented for the helium atom to estimate the distance to the inner and outer electron from the nucleus, the angle between electrons and the energy levels. The method is algebraic and is not based on the choice of correct trial wave function. Three harmonic oscillators and thus three quantum numbers are sufficient to describe the two-electron system. We derive a simple formula for the energy in the general case and in the special case of the Wannier Ridge. For a set of quantum numbers the distance to the electrons and the angle between the electrons are uniquely determined as the intersection between three surfaces. We show that the excited states converge either towards ionization thresholds or towards extreme parallel or antiparallel states and provide an estimate of the ground state energy.

  18. Nuclear Excitations by Antiprotons and Antiprotonic Atoms

    CERN Multimedia

    2002-01-01

    The proposal aims at the investigation of nuclear excitations following the absorption and annihilation of stopped antiprotons in heavier nuclei and at the same time at the study of the properties of antiprotonic atoms. The experimental arrangement will consist of a scintillation counter telescope for the low momentum antiproton beam from LEAR, a beam degrader, a pion multiplicity counter, a monoisotopic target and Ge detectors for radiation and charged particles. The data are stored by an on-line computer.\\\\ \\\\ The Ge detectors register antiprotonic x-rays and nuclear @g-rays which are used to identify the residual nucleus and its excitation and spin state. Coincidences between the two detectors will indicate from which quantum state the antiprotons are absorbed and to which nuclear states the various reactions are leading. The measured pion multiplicity characterizes the annihilation process. Ge&hyphn. and Si-telescopes identify charged particles and determine their energies.\\\\ \\\\ The experiment will gi...

  19. Nucleus Pearl Coating Process of Freshwater Mussel Anodonta woodiana (Unionidae

    Directory of Open Access Journals (Sweden)

    WASMEN MANALU

    2013-03-01

    Full Text Available The limiting factor which is a weakness of sea water pearl production are high costs, the risk of major business failures and a long coating time. From the issue of freshwater pearls appear to have prospects of alternative substitution for sea water pearl. This present study aimed to evaluate effect of loads (the number and diameter nucleus on freshwater pearl coating process and the number and size of the appropriate nucleus diameter, to produce the optimum coating thickness of half-round pearls. The research consists of experimental implantation of 2, 4, and 6 nucleus number per individual mussel was maintained by the method stocked in hapa in bottom waters. Observation method and factorial randomized block design used in the study of the influence of the load to the successfulness of pearl coating and the pearl layer thickness. The results showed that A. woodiana can be utilized as a producer of freshwater pearls. In addition, the number of optimum nucleus that can be attached to the mussel A. woodiana was 2 grains/individuals with a diameter of 10 mm. Shells implanted with the optimum nucleus diameter and number of pearls produced the highest layer thickness of 17 m after 9 months cultivation. This result was good enough compared with the layer thickness of sea water pearl production after the same cultivation time.

  20. Measurements of the near-nucleus coma of comet 67P/Churyumov-Gerasimenko with the Alice far-ultraviolet spectrograph on Rosetta

    Science.gov (United States)

    Feldman, Paul D.; A'Hearn, Michael F.; Bertaux, Jean-Loup; Feaga, Lori M.; Parker, Joel Wm.; Schindhelm, Eric; Steffl, Andrew J.; Stern, S. Alan; Weaver, Harold A.; Sierks, Holger; Vincent, Jean-Baptiste

    2015-11-01

    Aims: The Alice far-ultraviolet spectrograph onboard Rosetta is designed to observe emissions from various atomic and molecular species from within the coma of comet 67P/ Churyumov-Gerasimenko and to determine their spatial distribution and evolution with time and heliocentric distance. Methods: Following orbit insertion in August 2014, Alice made observations of the inner coma above the limbs of the nucleus of the comet from cometocentric distances varying between 10 and 80 km. Depending on the position and orientation of the slit relative to the nucleus, emissions of atomic hydrogen and oxygen were initially detected. These emissions are spatially localized close to the nucleus and spatially variable with a strong enhancement above the comet's neck at northern latitudes. Weaker emission from atomic carbon and CO were subsequently detected. Results: Analysis of the relative line intensities suggests photoelectron impact dissociation of H2O vapor as the source of the observed H i and O i emissions. The electrons are produced by photoionization of H2O. The observed C i emissions are also attributed to electron impact dissociation, of CO2, and their relative brightness to H i reflects the variation of CO2 to H2O column abundance in the coma.

  1. Vacuum low-temperature superconductivity is the essence of superconductivity - Atomic New Theory

    Science.gov (United States)

    Yongquan, Han

    2010-10-01

    The universe when the temperature closest to the Big Bang the temperature should be nuclear. Because, after the big bang, instant formation of atoms, nuclei and electrons between the absolute vacuum, the nucleus can not emit energy. (Radioactive elements, except in fact, radiation Yuan Su limited power emitted) which causes atomic nuclei and external temperature difference are so enormous that a large temperature difference reasons, all external particles became closer to the nucleus, affect the motion of electrons. When the conductor conductivity and thus affect the conductivity, the formation of resistance. Assumption that no particles affect the motion of electrons (except outside the nucleus) to form a potential difference will not change after the vector form, is now talking about the phenomenon of superconductivity, and then to introduce general, the gap between atoms in molecules or between small, valence electron number of high temperature superconducting conductors. This theory of atomic nuclei, but also explain the atomic and hydrogen bombs can remain after an explosion Why can release enormous energy reasons. Can also explain the ``super flow'' phenomenon. natural world. Tel 13241375685

  2. Evanescent Wave Atomic Mirror

    Science.gov (United States)

    Ghezali, S.; Taleb, A.

    2008-09-01

    A research project at the "Laboratoire d'électronique quantique" consists in a theoretical study of the reflection and diffraction phenomena via an atomic mirror. This poster presents the principle of an atomic mirror. Many groups in the world have constructed this type of atom optics experiments such as in Paris-Orsay-Villetaneuse (France), Stanford-Gaithersburg (USA), Munich-Heidelberg (Germany), etc. A laser beam goes into a prism with an incidence bigger than the critical incidence. It undergoes a total reflection on the plane face of the prism and then exits. The transmitted resulting wave out of the prism is evanescent and repulsive as the frequency detuning of the laser beam compared to the atomic transition δ = ωL-ω0 is positive. The cold atomic sample interacts with this evanescent wave and undergoes one or more elastic bounces by passing into backward points in its trajectory because the atoms' kinetic energy (of the order of the μeV) is less than the maximum of the dipolar potential barrier ℏΩ2/Δ where Ω is the Rabi frequency [1]. In fact, the atoms are cooled and captured in a magneto-optical trap placed at a distance of the order of the cm above the prism surface. The dipolar potential with which interact the slow atoms is obtained for a two level atom in a case of a dipolar electric transition (D2 Rubidium transition at a wavelength of 780nm delivered by a Titane-Saphir laser between a fundamental state Jf = l/2 and an excited state Je = 3/2). This potential is corrected by an attractive Van der Waals term which varies as 1/z3 in the Lennard-Jones approximation (typical atomic distance of the order of λ0/2π where λ0 is the laser wavelength) and in 1/z4 if the distance between the atom and its image in the dielectric is big in front of λ0/2π. This last case is obtained in a quantum electrodynamic calculation by taking into account an orthornormal base [2]. We'll examine the role of spontaneous emission for which the rate is inversely

  3. Physics of atomic nuclei

    CERN Document Server

    Zelevinsky, Vladimir

    2016-01-01

    This advanced textbook presents an extensive and diverse study of low-energy nuclear physics considering the nucleus as a quantum system of strongly interacting constituents. The contents guide students from the basic facts and ideas to more modern topics including important developments over the last 20 years, resulting in a comprehensive collection of major modern-day nuclear models otherwise unavailable in the current literature. The book emphasizes the common features of the nucleus and other many-body mesoscopic systems currently in the center of interest in physics. The authors have also included full problem sets that can be selected by lecturers and adjusted to specific interests for more advanced students, with many chapters containing links to freely available computer code. As a result, readers are equipped for scientific work in mesoscopic physics.

  4. Optimal reactions for the synthesis of superheavy nucleus 270Hs

    Institute of Scientific and Technical Information of China (English)

    LIU Zuhua; BAO Jingdong

    2006-01-01

    The superheavy nucleus 270 Hs iS expected to be a "double-magic" deformed nucleus.We have calculated its cross sections of evaporation residue for the reactions 248Cm(26Mg,4n)270Hs,244pu(30Si,4n)270Hs,238U(36S,4n)270Hs and 226Ra(48Ca,4n)270Hs using a two-parameter Smoluchowski equation.It is found from our results that 226Ra(48Ca,4n)270Hs and 238U(36S,4n)270Hs are two optimal reactions for the synthesis of the superheavy nucleus 270Hs due to their large negative Q-values.

  5. Microinjection of limonene into caudate nucleus inhibits IMC of rats

    Institute of Scientific and Technical Information of China (English)

    Hong Guo; Xin Yi Zhu; Yi Quan Wei; De Zhi Yang

    2000-01-01

    AIM We have discovered that Limonene modulates interdigestive myoelectrical complexes (IMCs) ofgastrointestinal tract in rats. In this research we will elucidate weather limonene affects acetylcholine M-receptor in caudate nucleus.METHODS Changes of IMCs were studied after limonene and/or atropine were microinjected into caudatenucleus. IMCs were recorded by a RM-6200 four-channel recorder and then delivered to Maclab and PowerMacintosh.RESULTS The active phases of IMCs occupied about 40% of total cycle in average. After microinjection oflimonene into caudate nucleus, the active phases were significantly shortened, while the cycle time of IMCswere not changed significantly. The inhibitory effects of limonene were abolished by pretreatment withatropine, whilst the atropine has no effect on IMCs.CONCLUSION It is suggested that limonene inhabits the gastrointestinal IMCs by affecting M-receptor incaudate nucleus.

  6. Extreme alpha-clustering in the 18O nucleus

    CERN Document Server

    Johnson, E D; Goldberg, V Z; Brown, S; Robson, D; Crisp, A M; Cottle, P D; Fu, C; Giles, J; Green, B W; Kemper, K W; Lee, K; Roeder, B T; Tribble, R E

    2009-01-01

    The structure of the 18O nucleus at excitation energies above the alpha decay threshold was studied using 14C+alpha resonance elastic scattering. A number of states with large alpha reduced widths have been observed, indicating that the alpha-cluster degree of freedom plays an important role in this N not equal Z nucleus. However, the alpha-cluster structure of this nucleus is very different from the relatively simple pattern of strong alpha-cluster quasi-rotational bands in the neighboring 16O and 20Ne nuclei. A 0+ state with an alpha reduced width exceeding the single particle limit was identified at an excitation energy of 9.9+/-0.3 MeV. We discuss evidence that states of this kind are common in light nuclei and give possible explanations of this feature.

  7. Dynamics in the Gravitational Field of a Cometary Nucleus

    CERN Document Server

    Jiang, Yu

    2014-01-01

    The study of dynamics near the comet is a very important topic in orbital mechanics. In this paper we are interested in analyzing the dynamical behaviors in the vicinity of a cometary nucleus. Equilibrium points and periodic orbits are discussed. There are four equilibrium points in the potential of the comet 1P/Halley nucleus, positions and eigenvalues of these equilibrium points are presented. About the periodic orbits, it is found that there are five topological classes of stably periodic orbits and six topological classes of unstably periodic orbits in the potential field of a cometary nucleus. It is found that the resonant periodic orbit can be stable, and there exist stably non-resonant periodic orbits, stably resonant periodic orbits and unstably resonant periodic orbits in the potential field of cometary nuclei. The periodic orbits with the 1:1, 1:2, and 1:8 resonances are presented.

  8. New integral formula and its applications to light nucleus reactions

    CERN Document Server

    Sun, Xiaojun

    2015-01-01

    A new integral formula, which has not been compiled in any integral tables or mathematical softwares, is proposed to obtain the analytical energy-angular spectra of the particles that are sequentially emitted from the discrete energy levels of the residual nuclei in the statistical theory of light nucleus reaction (STLN). In the cases of the neutron induced light nucleus reactions, the demonstration of the kinetic energy conservation in the sequential emission processes becomes straightforward thanks to this new integral formula and it is also helpful to largely reduce the volume of file-6 in nuclear reaction databases. Furthermore, taking p+$^9$Be reaction at 18 MeV as an example, this integral formula is extended to calculate the energy-angular spectra of the sequentially emitted neutrons for proton induced light nucleus reactions in the frame of STLN.

  9. Atoms, Molecules, and Compounds

    CERN Document Server

    Manning, Phillip

    2007-01-01

    Explores the atoms that govern chemical processes. This book shows how the interactions between simple substances such as salt and water are crucial to life on Earth and how those interactions are predestined by the atoms that make up the molecules.

  10. Multiphoton ionization of atoms

    International Nuclear Information System (INIS)

    The paper is devoted to the analysis of high intensity effects which result from multiphoton ionization of atoms in a high laser intensity, ranging from 1010 to 1015 W cm-2. Resonant multiphoton ionization of atoms, the production of multiply charged ions, and electron energy spectra, are all discussed. (U.K.)

  11. When Atoms Want

    Science.gov (United States)

    Talanquer, Vicente

    2013-01-01

    Chemistry students and teachers often explain the chemical reactivity of atoms, molecules, and chemical substances in terms of purposes or needs (e.g., atoms want or need to gain, lose, or share electrons in order to become more stable). These teleological explanations seem to have pedagogical value as they help students understand and use…

  12. Atomic Energy Control Board

    International Nuclear Information System (INIS)

    This paper has been prepared to provide an overview of the responsibilities and activities of the Atomic Energy Control Board. It is designed to address questions that are often asked concerning the establishment of the Atomic Energy Control Board, its enabling legislation, licensing and compliance activities, federal-provincial relationships, international obligations, and communications with the public

  13. Immobility, inheritance and plasticity of shape of the yeast nucleus

    Directory of Open Access Journals (Sweden)

    Andrulis Erik D

    2007-11-01

    Full Text Available Abstract Background Since S. cerevisiae undergoes closed mitosis, the nuclear envelope of the daughter nucleus is continuous with that of the maternal nucleus at anaphase. Nevertheless, several constitutents of the maternal nucleus are not present in the daughter nucleus. The present study aims to identify proteins which impact the shape of the yeast nucleus and to learn whether modifications of shape are passed on to the next mitotic generation. The Esc1p protein of S. cerevisiae localizes to the periphery of the nucleoplasm, can anchor chromatin, and has been implicated in targeted silencing both at telomeres and at HMR. Results Upon increased Esc1p expression, cell division continues and dramatic elaborations of the nuclear envelope extend into the cytoplasm. These "escapades" include nuclear pores and associate with the nucleolus, but exclude chromatin. Escapades are not inherited by daughter nuclei. This exclusion reflects their relative immobility, which we document in studies of prezygotes. Moreover, excess Esc1p affects the levels of multiple transcripts, not all of which originate at telomere-proximal loci. Unlike Esc1p and the colocalizing protein, Mlp1p, overexpression of selected proteins of the inner nuclear membrane is toxic. Conclusion Esc1p is the first non-membrane protein of the nuclear periphery which – like proteins of the nuclear lamina of higher eukaryotes – can modify the shape of the yeast nucleus. The elaborations of the nuclear envelope ("escapades" which appear upon induction of excess Esc1p are not inherited during mitotic growth. The lack of inheritance of such components could help sustain cell growth when parental nuclei have acquired potentially deleterious characteristics.

  14. Brain networks modulated by subthalamic nucleus deep brain stimulation.

    Science.gov (United States)

    Accolla, Ettore A; Herrojo Ruiz, Maria; Horn, Andreas; Schneider, Gerd-Helge; Schmitz-Hübsch, Tanja; Draganski, Bogdan; Kühn, Andrea A

    2016-09-01

    Deep brain stimulation of the subthalamic nucleus is an established treatment for the motor symptoms of Parkinson's disease. Given the frequent occurrence of stimulation-induced affective and cognitive adverse effects, a better understanding about the role of the subthalamic nucleus in non-motor functions is needed. The main goal of this study is to characterize anatomical circuits modulated by subthalamic deep brain stimulation, and infer about the inner organization of the nucleus in terms of motor and non-motor areas. Given its small size and anatomical intersubject variability, functional organization of the subthalamic nucleus is difficult to investigate in vivo with current methods. Here, we used local field potential recordings obtained from 10 patients with Parkinson's disease to identify a subthalamic area with an analogous electrophysiological signature, namely a predominant beta oscillatory activity. The spatial accuracy was improved by identifying a single contact per macroelectrode for its vicinity to the electrophysiological source of the beta oscillation. We then conducted whole brain probabilistic tractography seeding from the previously identified contacts, and further described connectivity modifications along the macroelectrode's main axis. The designated subthalamic 'beta' area projected predominantly to motor and premotor cortical regions additional to connections to limbic and associative areas. More ventral subthalamic areas showed predominant connectivity to medial temporal regions including amygdala and hippocampus. We interpret our findings as evidence for the convergence of different functional circuits within subthalamic nucleus' portions deemed to be appropriate as deep brain stimulation target to treat motor symptoms in Parkinson's disease. Potential clinical implications of our study are illustrated by an index case where deep brain stimulation of estimated predominant non-motor subthalamic nucleus induced hypomanic behaviour.

  15. Silk fibroin porous scaffolds for nucleus pulposus tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Chao; Yang, Qiang [Department of Spine Surgery, Tianjin Hospital, Tianjin 300211 (China); Tianjin Medical University, Tianjin 300070 (China); Zhu, Meifeng [The Key Laboratory of Bioactive Materials, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071 (China); Du, Lilong [Department of Spine Surgery, Tianjin Hospital, Tianjin 300211 (China); Tianjin Medical University, Tianjin 300070 (China); Zhang, Jiamin [The Key Laboratory of Bioactive Materials, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071 (China); Ma, Xinlong [Department of Spine Surgery, Tianjin Hospital, Tianjin 300211 (China); Xu, Baoshan, E-mail: xubaoshan99@126.com [Department of Spine Surgery, Tianjin Hospital, Tianjin 300211 (China); Wang, Lianyong, E-mail: wly@nankai.edu.cn [The Key Laboratory of Bioactive Materials, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071 (China)

    2014-04-01

    Intervertebral discs (IVDs) are structurally complex tissue that hold the vertebrae together and provide mobility to spine. The nucleus pulposus (NP) degeneration often results in degenerative IVD disease that is one of the most common causes of back and neck pain. Tissue engineered nucleus pulposus offers an alternative approach to regain the function of the degenerative IVD. The aim of this study is to determine the feasibility of porous silk fibroin (SF) scaffolds fabricated by paraffin-sphere-leaching methods with freeze-drying in the application of nucleus pulposus regeneration. The prepared scaffold possessed high porosity of 92.38 ± 5.12% and pore size of 165.00 ± 8.25 μm as well as high pore interconnectivity and appropriate mechanical properties. Rabbit NP cells were seeded and cultured on the SF scaffolds. Scanning electron microscopy, histology, biochemical assays and mechanical tests revealed that the porous scaffolds could provide an appropriate microstructure and environment to support adhesion, proliferation and infiltration of NP cells in vitro as well as the generation of extracellular matrix. The NP cell–scaffold construction could be preliminarily formed after subcutaneously implanted in a nude mice model. In conclusion, The SF porous scaffold offers a potential candidate for tissue engineered NP tissue. - Highlights: • Paraffin microsphere-leaching method is used to fabricate silk fibroin scaffold. • The scaffold has appropriate mechanical property, porosity and pore size • The scaffold supports growth and infiltration of nucleus pulposus cells. • Nucleus pulposus cells can secrete extracellular matrix in the scaffolds. • The scaffold is a potential candidate for tissue engineered nucleus pulposus.

  16. The transverse-energy distributions of 32S-nucleus collisions at 200 GeV per nucleon

    International Nuclear Information System (INIS)

    Transverse-energy distributions have been measured for the collisions of the 32S nucleus with Al, Ag, W, Pt, Pb and U target nuclei, at an incident energy of 200 GeV per nucleon. The shapes of these distribution reflect the geometry of the collisions, including the deformation effects. For central collisions, the transverse-energy production in the region -0.1 lab 0.5, where A is the atomic mass number of the target. This increase is accompanied by a relative depletion in the forward region ηlab > 2.9. These results are compared with those obtained under similar conditions with incident 16O nuclei. A comparison is also made with the predictions of a Monte Carlo generator based on the dual parton model. Finally, we give estimates of the energy density reached and its dependence on the atomic mass number of the projectile. (orig.)

  17. Atomic diffusion in stars

    CERN Document Server

    Michaud, Georges; Richer, Jacques

    2015-01-01

    This book gives an overview of atomic diffusion, a fundamental physical process, as applied to all types of stars, from the main sequence to neutron stars. The superficial abundances of stars as well as their evolution can be significantly affected. The authors show where atomic diffusion plays an essential role and how it can be implemented in modelling.  In Part I, the authors describe the tools that are required to include atomic diffusion in models of stellar interiors and atmospheres. An important role is played by the gradient of partial radiative pressure, or radiative acceleration, which is usually neglected in stellar evolution. In Part II, the authors systematically review the contribution of atomic diffusion to each evolutionary step. The dominant effects of atomic diffusion are accompanied by more subtle effects on a large number of structural properties throughout evolution. One of the goals of this book is to provide the means for the astrophysicist or graduate student to evaluate the importanc...

  18. Antiprotonic-hydrogen atoms

    International Nuclear Information System (INIS)

    Experimental studies of antiprotonic-hydrogen atoms have recently made great progress following the commissioning of the low energy antiproton facility (LEAR) at CERN in 1983. At the same time our understanding of the atomic cascade has increased considerably through measurements of the X-ray spectra. The life history of the p-bar-p atom is considered in some detail, from the initial capture of the antiproton when stopping in hydrogen, through the atomic cascade with the emission of X-rays, to the final antiproton annihilation and production of mesons. The experiments carried out at LEAR are described and the results compared with atomic cascade calculations and predictions of strong interaction effects. (author)

  19. Moving Single Atoms

    Science.gov (United States)

    Stuart, Dustin

    2016-05-01

    Single neutral atoms are promising candidates for qubits, the fundamental unit of quantum information. We have built a set of optical tweezers for trapping and moving single Rubidium atoms. The tweezers are based on a far off-resonant dipole trapping laser focussed to a 1 μm spot with a single aspheric lens. We use a digital micromirror device (DMD) to generate dynamic holograms of the desired arrangement of traps. The DMD has a frame rate of 20 kHz which, when combined with fast algorithms, allows for rapid reconfiguration of the traps. We demonstrate trapping of up to 20 atoms in arbitrary arrangements, and the transport of a single-atom over a distance of 14 μm with continuous laser cooling, and 5 μm without. In the meantime, we are developing high-finesse fibre-tip cavities, which we plan to use to couple pairs of single atoms to form a quantum network.

  20. Spectra Statistics for the Odd-Odd Nucleus 86Nb

    Institute of Scientific and Technical Information of China (English)

    ZHENG Ren-Rong; ZHU Shun-Quan; CHENG Nan-Pu

    2001-01-01

    The energy levels of the odd-odd nucleus 86 Nb at low spins are calculated by using quasi-particles plus a rotor model. The distribution of the nearest-neighbour spacing and the spectral rigidity are studied. We find that the chaotic degree of the energy spectra increases with the increasing spin and reaches a maximum at I = 10; then it decreases gradually for spins above I = 10. The recoil term in the model Haniltonian makes the energy spectra slightly regular. The Coriolis force, however, makes the spectra chaotic and plays a major role in the spectral statistics of the odd-odd nucleus 86Nb.

  1. Final State Interactions Effects in Neutrino-Nucleus Interactions

    Energy Technology Data Exchange (ETDEWEB)

    Golan, Tomasz [Univ. of Wroctaw (Poland); Juszczak, Cezary [Univ. of Wroctaw (Poland); Sobczyk, Jan T. [Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States)

    2012-07-01

    Final State Interactions effects are discussed in the context of Monte Carlo simulations of neutrino-nucleus interactions. A role of Formation Time is explained and several models describing this effect are compared. Various observables which are sensitive to FSI effects are reviewed including pion-nucleus interaction and hadron yields in backward hemisphere. NuWro Monte Carlo neutrino event generator is described and its ability to understand neutral current $\\pi^0$ production data in $\\sim 1$ GeV neutrino flux experiments is demonstrated.

  2. Recent Developments in Neutrino/Antineutrino-Nucleus Interactions

    Energy Technology Data Exchange (ETDEWEB)

    Morfín, Jorge G.; Nieves, Juan; Sobczyk, Jan T.

    2012-01-01

    Recent experimental results and developments in the theoretical treatment of neutrino-nucleus interactions in the energy range of 1–10 GeV are discussed. Difficulties in extracting neutrino-nucleon cross sections from neutrino-nucleus scattering data are explained and significance of understanding nuclear effects for neutrino oscillation experiments is stressed. Detailed discussions of the status of two-body current contribution in the kinematic region dominated by quasielastic scattering and specific features of partonic nuclear effects in weak DIS scattering are presented.

  3. An occultation of the inner Seyfert nucleus of NGC 4151

    International Nuclear Information System (INIS)

    The brightness of the unresolved nucleus of NGC 4151 was monitored over five months in 1983. Variations of ≅ 0.1 mag/day were observed in the U-band and no significant variation was found of the -OIII] 5007 A emission line. However, an event that was observed on the nights of the 10/11 and 11/12 February 1983 in the continuum around 5672 A has all the characteristics of an occultation. It is proposed that an inner synchrotron nucleus of ≅ 3 a.u. diameter was occulted by an opaque cloud ≅ 6 a.u. across on those two nights

  4. Sensitivity of reaction cross sections to halo nucleus density distributions

    OpenAIRE

    Alkhazov, G. D.; Sarantsev, V. V.

    2013-01-01

    In order to clear up the sensitivity of the nucleus--nucleus reaction cross sections $\\sigma_R$ to the nuclear matter distributions in exotic halo nuclei, we have calculated the values of $\\sigma_R$ for scattering of $^6$He, $^{11}$Li, and $^{19}$C nuclei on several nuclear targets at the energy of 0.8 GeV/nucleon. The calculations were performed in the "rigid target" approximation to the Glauber theory, different shapes of the nuclear density distributions in $^6$He, $^{11}$Li, and $^{19}$C ...

  5. Hyper deformation and clustering configuration in 168Yb nucleus

    International Nuclear Information System (INIS)

    Recently an exhaustive experimental search for hyper deformation in 168Yb with β ∼ 1.0 and axis ratio 3:1 at spins 70-80ℎ has yielded negative result which is attributed either to the fact that the fission of the compound nucleus prevented population of hyper deformed states or that the amount of angular momentum brought into the compound system was not sufficient to allow population of hyper deformed states. A systematic theoretical search for detection of such hyper deformation in this nucleus using the cranked Nilsson Strutinsky method with tuning to fixed spins was undertaken

  6. Electromagnetic properties of the Beryllium-11 nucleus in Halo EFT

    OpenAIRE

    Hammer H.-W.; Phillips D.R.

    2010-01-01

    We compute electromagnetic properties of the Beryllium-11 nucleus using an effective field theory that exploits the separation of scales in this halo system. We fix the parameters of the EFT from measured data on levels and scattering lengths in the 10Be plus neutron system. We then obtain predictions for the B(E1) strength of the 1/2+ to 1/2− transition in the 11Be nucleus. We also compute the charge radius of the ground state of 11Be. Agreement with experiment within the expected accurac...

  7. Low-energy rotational bands in the nucleus155Eu

    Science.gov (United States)

    Katajanheimo, R.; Liljavirta, H.; Siivola, A.; Hammarén, E.; Liukkonen, E.

    1984-02-01

    Excited states in the nucleus155Eu have been produced during in-beam bombardments of a154Sm target with3He beams at 22 and 27 MeV. Decay gamma rays were detected using coincidence equipment optimized for low-energy photons. The level scheme is based on the observed γγ-coincidence relationships combined with the information on relative intensities. Tentatively suggested spin assignments follow from the apparent rotational character of the nucleus. Experimental observations are compared with predictions calculated from a particle-rotor model with a nonspheroidal Woods-Saxon potential.

  8. Formation and decay of a hot compound nucleus

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, B.V.; Dalmolin, F.T.; Dutra, M.; Santos, T.J., E-mail: brett@ita.br [Instituto Tecnologico de Aeronautica (ITA), Sao Jose dos Campos SP (Brazil); Souza, S.R. [Universidade Federal de Rio Grande do Sul (UFRS), Porto Alegre RS, (Brazil); Universidade Federal de Rio de Janeiro (UFRJ), RJ (Brazil). Instituto de Fisica; Donangelo, R. [Instituto de Fisica, Universidad de la Republica de Uruguay, Montevideo (Uruguay); Universidade Federal de Rio Grande do Sul (UFRS), Porto Alegre RS, (Brazil)

    2014-07-01

    The compound nucleus plays an important role in nuclear reactions over a wide range of projectile-target combinations and energies. The limits that angular momentum places on its formation and existence are, for the most part, well understood. The limits on its excitation energy are not as clear. Here we first analyze general geometrical and thermodynamical features of a hot compound nucleus. We then discuss the manners by which it can decay and close by speculating on the high energy limit to its formation and existence. (author)

  9. Recent Developments in Neutrino/Antineutrino-Nucleus Interactions

    Directory of Open Access Journals (Sweden)

    Jorge G. Morfín

    2012-01-01

    Full Text Available Recent experimental results and developments in the theoretical treatment of neutrino-nucleus interactions in the energy range of 1–10 GeV are discussed. Difficulties in extracting neutrino-nucleon cross sections from neutrino-nucleus scattering data are explained and significance of understanding nuclear effects for neutrino oscillation experiments is stressed. Detailed discussions of the status of two-body current contribution in the kinematic region dominated by quasielastic scattering and specific features of partonic nuclear effects in weak DIS scattering are presented.

  10. Atoms and Molecules Interacting with Light

    Science.gov (United States)

    van der Straten, Peter; Metcalf, Harold

    2016-02-01

    Part I. Atom-Light Interaction: 1. The classical physics pathway; Appendix 1.A. Damping force on an accelerating charge; Appendix 1.B. Hanle effect; Appendix 1.C. Optical tweezers; 2. Interaction of two-level atoms and light; Appendix 2.A. Pauli matrices for motion of the bloch vector; Appendix 2.B. The Ramsey method; Appendix 2.C. Echoes and interferometry; Appendix 2.D. Adiabatic rapid passage; Appendix 2.E Superposition and entanglement; 3. The atom-light interaction; Appendix 3.A. Proof of the oscillator strength theorem; Appendix 3.B. Electromagnetic fields; Appendix 3.C. The dipole approximation; Appendix 3.D. Time resolved fluorescence from multi-level atoms; 4. 'Forbidden' transitions; Appendix 4.A. Higher order approximations; 5. Spontaneous emission; Appendix 5.A. The quantum mechanical harmonic oscillator; Appendix 5.B. Field quantization; Appendix 5.C. Alternative theories to QED; 6. The density matrix; Appendix 6.A. The Liouville-von Neumann equation; Part II. Internal Structure: 7. The hydrogen atom; Appendix 7.A. Center-of-mass motion; Appendix 7.B. Coordinate systems; Appendix 7.C. Commuting operators; Appendix 7.D. Matrix elements of the radial wavefunctions; 8. Fine structure; Appendix 8.A. The Sommerfeld fine-structure constant; Appendix 8.B. Measurements of the fine structure 9. Effects of the nucleus; Appendix 9.A. Interacting magnetic dipoles; Appendix 9.B. Hyperfine structure for two spin =2 particles; Appendix 9.C. The hydrogen maser; 10. The alkali-metal atoms; Appendix 10.A. Quantum defects for the alkalis; Appendix 10.B. Numerov method; 11. Atoms in magnetic fields; Appendix 11.A. The ground state of atomic hydrogen; Appendix 11.B. Positronium; Appendix 11.C. The non-crossing theorem; Appendix 11.D. Passage through an anticrossing: Landau-Zener transitions; 12. Atoms in electric fields; 13. Rydberg atoms; 14. The helium atom; Appendix 14.A. Variational calculations; Appendix 14.B. Detail on the variational calculations of the ground state

  11. Analysis of Intermediate-Energy Nucleus-Nucleus Spallation, Fission, and Fragmentation Reactions with the LAQGSM code

    CERN Document Server

    Mashnik, S G; Prael, R E; Sierk, A J

    2003-01-01

    The LAQGSM code has been recently developed at Los Alamos National Laboratory to simulate nuclear reactions for proton radiography applications. We have benchmarked our code against most available measured data both for proton-nucleus and nucleus-nucleus interactions at incident energies from 10 MeV to 800 GeV and have compared our results with predictions of other current models used by the nuclear community. Here, we present a brief description of our code and show illustrative results obtained with LAQGSM for neutron spectra measured recently by Nakamura's groups for reactions induced by light and medium nuclei on targets from C to Pb at several incident energies from 95 to 600 MeV/nucleon and with the recent GSI measurements of spallation, fission, and fragmentation yields from A+p and A+A reactions at incident energies near and below 1 GeV/nucleon. Further necessary work is outlined.

  12. A comparative analysis of mechanisms of fast light particles production in nucleus-nucleus collisions at low and intermediate energies

    CERN Document Server

    Denikin, A S

    2002-01-01

    The dynamics and the mechanisms of formation of pre-equilibrium light particles in nucleus-nucleus collisions at low and intermediate energies are discussed in terms of a classical four-body model. The energy and angular distributions of light particles have been calculated. It has been found that at energies lower than 50A MeV the formation of the most high-energy part of the nuclear spectrum occurs at the expense of the acceleration of light target particles with the mean field of the projectile. The obtained data are in good agreement with available experimental data

  13. Linear atomic quantum coupler

    CERN Document Server

    El-Orany, Faisal A A

    2009-01-01

    In this paper, we develop the notion of the linear atomic quantum coupler. This device consists of two modes propagating into two waveguides, each of them includes a localized and/or a trapped atom. These waveguides are placed close enough to allow exchanging energy between them via evanescent waves. Each mode interacts with the atom in the same waveguide in the standard way, i.e. as the Jaynes-Cummings model (JCM), and with the atom-mode in the second waveguide via evanescent wave. We present the Hamiltonian for the system and deduce the exact form for the wavefunction. We investigate the atomic inversions and the second-order correlation function. In contrast to the conventional linear coupler, the atomic quantum coupler is able to generate nonclassical effects. The atomic inversions can exhibit long revival-collapse phenomenon as well as subsidiary revivals based on the competition among the switching mechanisms in the system. Finally, under certain conditions, the system can yield the results of the two-m...

  14. 78 FR 58571 - Maine Yankee Atomic Power Company, Connecticut Yankee Atomic Power Company, and The Yankee Atomic...

    Science.gov (United States)

    2013-09-24

    ... Atomic Power Company, Connecticut Yankee Atomic Power Company, and The Yankee Atomic Electric Company... Power Company (Maine Yankee), Connecticut Yankee Atomic Power Company (Connecticut Yankee), and the Yankee Atomic Electric Company (Yankee Atomic) (together, ``licensees'' or ``the Yankee Companies'')...

  15. Lattice model for amyloid peptides: OPEP force field parametrization and applications to the nucleus size of Alzheimer's peptides

    Science.gov (United States)

    Tran, Thanh Thuy; Nguyen, Phuong H.; Derreumaux, Philippe

    2016-05-01

    Coarse-grained protein lattice models approximate atomistic details and keep the essential interactions. They are, therefore, suitable for capturing generic features of protein folding and amyloid formation at low computational cost. As our aim is to study the critical nucleus sizes of two experimentally well-characterized peptide fragments Aβ16-22 and Aβ37-42 of the full length Aβ1-42 Alzheimer's peptide, it is important that simulations with the lattice model reproduce all-atom simulations. In this study, we present a comprehensive force field parameterization based on the OPEP (Optimized Potential for Efficient protein structure Prediction) force field for an on-lattice protein model, which incorporates explicitly the formation of hydrogen bonds and directions of side-chains. Our bottom-up approach starts with the determination of the best lattice force parameters for the Aβ16-22 dimer by fitting its equilibrium parallel and anti-parallel β-sheet populations to all-atom simulation results. Surprisingly, the calibrated force field is transferable to the trimer of Aβ16-22 and the dimer and trimer of Aβ37-42. Encouraged by this finding, we characterized the free energy landscapes of the two decamers. The dominant structure of the Aβ16-22 decamer matches the microcrystal structure. Pushing the simulations for aggregates between 4-mer and 12-mer suggests a nucleus size for fibril formation of 10 chains. In contrast, the Aβ37-42 decamer is largely disordered with mixed by parallel and antiparallel chains, suggesting that the nucleus size is >10 peptides. Our refined force field coupled to this on-lattice model should provide useful insights into the critical nucleation number associated with neurodegenerative diseases.

  16. Atomic Dark Matter

    OpenAIRE

    Kaplan, David E.; Krnjaic, Gordan Z.; Rehermann, Keith R.; Wells, Christopher M.

    2009-01-01

    We propose that dark matter is dominantly comprised of atomic bound states. We build a simple model and map the parameter space that results in the early universe formation of hydrogen-like dark atoms. We find that atomic dark matter has interesting implications for cosmology as well as direct detection: Protohalo formation can be suppressed below $M_{proto} \\sim 10^3 - 10^6 M_{\\odot}$ for weak scale dark matter due to Ion-Radiation interactions in the dark sector. Moreover, weak-scale dark a...

  17. EINSTEIN, SCHROEDINGER, AND ATOM

    Directory of Open Access Journals (Sweden)

    Trunev A. P.

    2014-03-01

    Full Text Available In this paper, we consider gravitation theory in multidimensional space. The model of the metric satisfying the basic requirements of quantum theory is proposed. It is shown that gravitational waves are described by the Liouville equation and the Schrodinger equation as well. The solutions of the Einstein equations describing the stationary states of arbitrary quantum and classical systems with central symmetry have been obtained. Einstein’s atom model has been developed, and proved that atoms and atomic nuclei can be represented as standing gravitational waves

  18. Atoms, molecules, solids

    International Nuclear Information System (INIS)

    This book is an introduction to modern physics for undergraduate students of physics or students of related fields. After an introduction to the wave-particle dualism the structure of atoms is considered with regards to atomic models. Then the foundations of quantum mechanics are introduced with regards to their application to atomic structure calculations. Thereafter the chemical bond and the molecular structure are discussed. Then classical and quantum statistical mechanics are introduced. Thereafter the crystal binding, the crystal structure, and the specific heat of solids are considered. Finally the band theory of solids is briefly introduced. Every chapter contains exercise problems. (HSI)

  19. Single-atom nanoelectronics

    CERN Document Server

    Prati, Enrico

    2013-01-01

    Single-Atom Nanoelectronics covers the fabrication of single-atom devices and related technology, as well as the relevant electronic equipment and the intriguing new phenomena related to single-atom and single-electron effects in quantum devices. It also covers the alternative approaches related to both silicon- and carbon-based technologies, also from the point of view of large-scale industrial production. The publication provides a comprehensive picture of the state of the art at the cutting edge and constitutes a milestone in the emerging field of beyond-CMOS technology. Although there are

  20. Atom probe tomography today

    Directory of Open Access Journals (Sweden)

    Alfred Cerezo

    2007-12-01

    Full Text Available This review aims to describe and illustrate the advances in the application of atom probe tomography that have been made possible by recent developments, particularly in specimen preparation techniques (using dual-beam focused-ion beam instruments but also of the more routine use of laser pulsing. The combination of these two developments now permits atomic-scale investigation of site-specific regions within engineering alloys (e.g. at grain boundaries and in the vicinity of cracks and also the atomic-level characterization of interfaces in multilayers, oxide films, and semiconductor materials and devices.

  1. Atom trap trace analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Z.-T.; Bailey, K.; Chen, C.-Y.; Du, X.; Li, Y.-M.; O' Connor, T. P.; Young, L.

    2000-05-25

    A new method of ultrasensitive trace-isotope analysis has been developed based upon the technique of laser manipulation of neutral atoms. It has been used to count individual {sup 85}Kr and {sup 81}Kr atoms present in a natural krypton sample with isotopic abundances in the range of 10{sup {minus}11} and 10{sup {minus}13}, respectively. The atom counts are free of contamination from other isotopes, elements,or molecules. The method is applicable to other trace-isotopes that can be efficiently captured with a magneto-optical trap, and has a broad range of potential applications.

  2. Division of atomic physics

    International Nuclear Information System (INIS)

    The Division of Atomic Physics, Lund Institute of Technology (LTH), is responsible for the basic physics teaching in all subjects at LTH and for specialized teaching in Optics, Atomic Physics, Atomic and Molecular Spectroscopy and Laser Physics. The Division has research activities in basic and applied optical spectroscopy, to a large extent based on lasers. It is also part of the Physics Department, Lund University, where it forms one of eight divisions. Since the beginning of 1980 the research activities of our division have been centred around the use of lasers. The activities during the period 1991-1992 is described in this progress reports

  3. Inside the Hydrogen Atom

    CERN Document Server

    Nowakowski, M; Fierro, D Bedoya; Manjarres, A D Bermudez

    2016-01-01

    We apply the non-linear Euler-Heisenberg theory to calculate the electric field inside the hydrogen atom. We will demonstrate that the electric field calculated in the Euler-Heisenberg theory can be much smaller than the corresponding field emerging from the Maxwellian theory. In the hydrogen atom this happens only at very small distances. This effect reduces the large electric field inside the hydrogen atom calculated from the electromagnetic form-factors via the Maxwell equations. The energy content of the field is below the pair production threshold.

  4. The CHIANTI atomic database

    CERN Document Server

    Young, Peter R; Landi, Enrico; Del Zanna, Giulio; Mason, Helen

    2015-01-01

    The CHIANTI atomic database was first released in 1996 and has had a huge impact on the analysis and modeling of emissions from astrophysical plasmas. The database has continued to be updated, with version 8 released in 2015. Atomic data for modeling the emissivities of 246 ions and neutrals are contained in CHIANTI, together with data for deriving the ionization fractions of all elements up to zinc. The different types of atomic data are summarized here and their formats discussed. Statistics on the impact of CHIANTI to the astrophysical community are given and examples of the diverse range of applications are presented.

  5. Empirical Example of Nucleus with Transitional Dynamical Symmetry X(5)

    Institute of Scientific and Technical Information of China (English)

    张大立; 赵惠英

    2002-01-01

    By analysing the energy spectrum, E2 transition rates and branching ratios, it is shown explicitly that the nucleus 150Nd provides an empirical example with X(5) symmetry at the critical point of the transition from U(5) to SU(3) symmetry.

  6. Nucleus accumbens dopamine receptors in the consolidation of spatial memory.

    NARCIS (Netherlands)

    Mele, A.; Avena, M.; Roullet, P.; Leonibus, E. de; Mandillo, S.; Sargolini, F.; Coccurello, R.; Oliverio, A.

    2004-01-01

    Nucleus accumbens dopamine is known to play an important role in motor activity and in behaviours governed by drugs and natural reinforcers, as well as in non-associative forms of learning. At the same time, activation of D1 and D2 dopamine receptors has been suggested to promote intracellular event

  7. Three-dimensional organization of the human interphase nucleus

    NARCIS (Netherlands)

    T.A. Knoch (Tobias); C. Münkel (Christian); W. Waldeck (Waldemar); J. Langowski (Jörg)

    2000-01-01

    textabstractDespite the successful linear sequencing of the human genome its three-dimensional structure is widely unknown, although it is important for gene regulation and replication. For a long time the interphase nucleus has been viewed as a 'spaghetti soup' of DNA without much internal structur

  8. Three-dimensional organization of the human interphase nucleus

    NARCIS (Netherlands)

    T.A. Knoch (Tobias); M. Wachsmuth (Malte); W. Waldeck (Waldemar); J. Langowski (Jörg)

    2002-01-01

    markdownabstractTo approach the three-dimensional organization of the human cell nucleus, the structural-, scaling- and dynamic properties of interphase chromosomes and cell nuclei were simulated with Monte Carlo and Brownian Dynamics methods. The 30 nm chromatin fibre was folded according to the Mu

  9. Three-dimensional organization of the human interphase nucleus.

    NARCIS (Netherlands)

    T.A. Knoch (Tobias); M. Wachsmuth (Malte); W. Waldeck (Waldemar); J. Langowski (Jörg)

    2002-01-01

    textabstractTo approach the three-dimensional organization of the human cell nucleus, the structural-, scaling- and dynamic properties of interphase chromosomes and cell nuclei were simulated with Monte Carlo and Brownian Dynamics methods. The 30 nm chromatin fibre was folded according to the Multi-

  10. Three-dimensional organization of the human interphase nucleus

    NARCIS (Netherlands)

    T.A. Knoch (Tobias); M. Wachsmuth (Malte); W. Waldeck (Waldemar); J. Langowski (Jörg)

    2002-01-01

    textabstractTo approach the three-dimensional organization of the human cell nucleus, the structural-, scaling- and dynamic properties of interphase chromosomes and cell nuclei were simulated with Monte Carlo and Brownian Dynamics methods. The 30 nm chromatin fibre was folded according to the Mul

  11. CTP synthase forms cytoophidia in the cytoplasm and nucleus

    Energy Technology Data Exchange (ETDEWEB)

    Gou, Ke-Mian [MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT (United Kingdom); State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193 (China); Chang, Chia-Chun [Institute of Biotechnology, National Taiwan University, Taipei, Taiwan, ROC (China); Shen, Qing-Ji [MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT (United Kingdom); Sung, Li-Ying, E-mail: liyingsung@ntu.edu.tw [Institute of Biotechnology, National Taiwan University, Taipei, Taiwan, ROC (China); Agricultural Biotechnology Research Center, Academia Sinica, Taipei 115, Taiwan, ROC (China); Liu, Ji-Long, E-mail: jilong.liu@dpag.ox.ac.uk [MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT (United Kingdom)

    2014-04-15

    CTP synthase is an essential metabolic enzyme responsible for the de novo synthesis of CTP. Multiple studies have recently showed that CTP synthase protein molecules form filamentous structures termed cytoophidia or CTP synthase filaments in the cytoplasm of eukaryotic cells, as well as in bacteria. Here we report that CTP synthase can form cytoophidia not only in the cytoplasm, but also in the nucleus of eukaryotic cells. Both glutamine deprivation and glutamine analog treatment promote formation of cytoplasmic cytoophidia (C-cytoophidia) and nuclear cytoophidia (N-cytoophidia). N-cytoophidia are generally shorter and thinner than their cytoplasmic counterparts. In mammalian cells, both CTP synthase 1 and CTP synthase 2 can form cytoophidia. Using live imaging, we have observed that both C-cytoophidia and N-cytoophidia undergo multiple rounds of fusion upon glutamine analog treatment. Our study reveals the coexistence of cytoophidia in the cytoplasm and nucleus, therefore providing a good opportunity to investigate the intracellular compartmentation of CTP synthase. - Highlights: • CTP synthase forms cytoophidia not only in the cytoplasm but also in the nucleus. • Glutamine deprivation and Glutamine analogs promotes cytoophidium formation. • N-cytoophidia exhibit distinct morphology when compared to C-cytoophidia. • Both CTP synthase 1 and CTP synthase 2 form cytoophidia in mammalian cells. • Fusions of cytoophidia occur in the cytoplasm and nucleus.

  12. Theory status of quarkonium production in proton-nucleus collisions

    CERN Document Server

    Lansberg, J P

    2015-01-01

    I give a brief overview of the recent theoretical progress in the study of quarkonium production in proton-nucleus collisions in view of the recent LHC and RHIC results. A special emphasis is put on the excited states such as the psi', Upsilon(2S) and Upsilon(3S).

  13. Parity non-conserving effects in neutron-nucleus scattering

    International Nuclear Information System (INIS)

    The present lecture reviews the motivations which led to study the contribution of the neutron-nucleus component to parity-non-conserving effects observed in medium-heavy nuclei and considers its present status. It is shown that it cannot account for those experimental data. The order interpretation of these effects, which cannot lead to precise statements, is schematically described

  14. Saturating Cronin effect in ultrarelativistic proton-nucleus collisions

    CERN Document Server

    Papp, G; Fái, G; Papp, Gabor; Levai, Peter; Fai, George

    2000-01-01

    Pion and photon production cross sections are analyzed in proton-proton and proton-nucleus collisions at energies 20 GeV < s^1/2 < 60 GeV. We separate the proton-proton and nuclear contributions to transverse-momentum broadening and suggest a new mechanism for the nuclear enhancement in the high transverse-momentum region.

  15. RELATIVISTIC CALCULATIONS OF THE SUPERHEAVY NUCLEUS 114-298

    NARCIS (Netherlands)

    BOERSMA, HF

    1993-01-01

    We investigate ground-state properties of the superheavy nucleus with N = 184 and Z = 114, (298)114, using conventional relativistic mean-field theory and density-dependent mean-field theory, which reproduces Dirac-Brueckner calculations in nuclear matter. Our calculations provide support for N = 18

  16. Deexcitation of superdeformed bands in the nucleus Tb-151

    NARCIS (Netherlands)

    Finck, C; Appelbe, D; Beck, FA; Byrski, T; Cullen, D; Curien, D; deFrance, G; Duchene, G; Erturk, S; Haas, B; Khadiri, N; Kharraja, B; Prevost, D; Rigollet, C; Stezowski, O; Twin, P; Vivien, JP; Zuber, K

    1997-01-01

    The aim of this work is to get more informations about the decay-out of superdeformed bands. One of the best candidates in the mass A similar or equal to 150 region for that kind of research is the nucleus Tb-151. From previous works, it has been established that the first excited band goes lower in

  17. Rapid feedback processing in human nucleus accumbens and motor thalamus

    NARCIS (Netherlands)

    Schüller, T.; Gründler, T.O.J.; Jocham, G.; Klein, T.A.; Timmermann, L.; Visser-Vandewalle, V.E.R.M.; Kuhn, J.

    2015-01-01

    The nucleus accumbens (NAcc) and thalamus are integral parts in models of feedback processing. Deep brain stimulation (DBS) has been successfully employed to alleviate symptoms of psychiatric conditions including obsessive-compulsive disorder (OCD) and Tourette's syndrome (TS). Common target structu

  18. Physical interrelation of volatile and refractories in a cometary nucleus

    Science.gov (United States)

    Fulle, Marco; Alice Team (PI Alan Stern), CONSTERT Team (PI Wlodek Kofman), COSIMA Team (PI Martin Hilchenbach), GIADA Team (PI Alessandra Rotundi), MIDAS Team (PI Mark Bentley), MIRO Team (PI Mark Hofstadter), OSIRIS Team (PI Holger Sierks), ROSINA Team (PI Kathrin Altwegg), RPC Team (PIs Hans Nilsson, James Burch, Anders Eriksson, Karl Heinz-Glassmeier, Pierre Henri, Christopher Carr), RSI Team (PI Martin Paetzold), VIRTIS Team (PI Fabrizio Capaccioni), Lander Team (Lead Scientists: Hermann Boehnhardt and Jean-Pierre Bibring), IDS Team (Eberhard Gruen, Marcello Fulchignoni, Paul Weissman), Project Scientist Team (Matt Taylor, Bonnie Buratti, Nicolas Altobelli, Mathieu Choukroun), Ground-Based Observations Team (Colin Snodgrass)

    2016-10-01

    The Rosetta mission has been taking measurements of its target comet Comet 67P/Churyumov-Gerasimenko since early 2014 and will complete operations at the end of September 2016. The mission Science Management Plan, in 1994, laid out the the prime goals and themes of the mission. These five themes were: 1) To study the global characterisation of the Nuclues, the determination of the dynamics properties , surface morpholy and composition of the comet. 2) Examination of the Chemical, Mineralogical and isotopic compositions of volatiles and refractories in a cometary nucleus.3) Physical interrelation of volatile and refractories in a cometary nucleus4) Study the development of cometary activity and the process in the surface layer of the nucleus and in the inner coma5) The origins of comets, the relationship between cometary and interstellar material and the implications for the origin of the solar system,To cover all aspects of the Rosetta mission in this special Show case session, this abstracts is one of 5, with this particular presentation focusing on theme 3, in particular on a) The dust-to-gas ratio; b) distributed sources of volatiles; c) seasonal evolution of the dust size distribution.a) The dust-to-gas ratio has been provided by coma observations measuring the gas and dust loss rates from the nucleus surface. The ratio of these two loss rates provides a lower limit of the dust-to-gas ratio at the nucleus surface, since it does not take into account the largest chunks unable to leave the nucleus, or falling back due to the dominant gravity. We review the value inferred so far, its time evolution, and new techniques to directly measure it in the nucleus.b) Evidences offered by Rosetta observations of gas sublimating from dust particles are up to now faint. We report the few available observations and an estimate of the probable average water content in dust particles inferred by 3D gas-dynamical codes of 67P coma.c) The dust-size distribution tunes the sizes

  19. Brackett Gamma Imaging of the Nucleus of M83

    Science.gov (United States)

    Crosthwaite, L. P.; Turner, J. L.; Beck, S. C.; Meier, D. S.

    2004-12-01

    The gas-rich nucleus of barred spiral galaxy, M83, is a hotbed of star formation, with a total infrared luminosity of 4 X 109 Lo. We have observed the nucleus of M83 with the near infrared spectrometer, NIRSPEC, on Keck 2 to obtain high resolution Brγ recombination line spectra of the nucleus. Simultaneous imaging with the SCAM camera in a broadband K filter shows the position of the slit on the near-infrared galaxy. This allows us to map the nucleus with a continuum reference. The SCAM image shows a bright peak at the nucleus and a complex semi-circular arc of emission to the southwest. We stepped the 0.5'' X 24'' length slit in small declination increments to map a 20'' X 20'' region just west of the nucleus. Individual spectra were used to form a ra-dec-lambda cube and an integrated intensity map of Brγ . A total of 1.1 X 10-16 W m-2 of Brγ emission is detected in the map, in good agreement with previous low resolution observations (Turner, Ho, & Beck 1987, ApJ, 313, 644). This is not corrected for extinction within the molecular clouds in M83 or to the nebulae themselves and is therefore a lower limit to the true Brγ flux. Extinction is estimated to be at least a magnitude in the near-IR as measured in larger (4'') beams (Turner et al.) The bulk of the Brγ emission extends along the northern portion of the near-IR continuum semi-circle. Twenty percent of the total Brγ emission comes from single a 3'' (FWHM) source located 5'' west of the near-IR nucleus. The complementary NIRSPEC Brα data we have obtained will eventually allow us to evaluate the near-IR extinction on subarcsecond sizescales and obtain an extinction-corrected estimate of the Lyman continuum rate and therefore the number of ionizing stars.

  20. Structures and functions in the crowded nucleus: new biophysical insights

    Directory of Open Access Journals (Sweden)

    Ronald eHancock

    2014-09-01

    Full Text Available Concepts and methods from the physical sciences have catalysed remarkable progress in understanding the cell nucleus in recent years. To share this excitement with physicists and encourage their interest in this field, this review offers an overview of how the physics which underlies structures and functions in the nucleus is becoming more clear thanks to methods which have been developed to simulate and study macromolecules, polymers, and colloids. The environment in the nucleus is very crowded with macromolecules, making entropic (depletion forces major determinants of interactions. Simulation and experiments are consistent with their key role in forming membraneless compartments such as nucleoli, PML and Cajal bodies, and discrete territories for chromosomes. The chromosomes, giant linear polyelectrolyte polymers, exist in vivo in a state like a polymer melt. Looped conformations are predicted in crowded conditions, and have been confirmed experimentally and are central to the regulation of gene expression. Polymer theory has revealed how the chromosomes are so highly compacted in the nucleus, forming a crumpled globule with fractal properties which avoids knots and entanglements in DNA while allowing facile accessibility for its replication and transcription. Entropic repulsion between looped polymers can explain the confinement of each chromosome to a discrete region of the nucleus. Crowding and looping are predicted to facilitate finding the specific targets of factors which modulate activities of DNA. Simulation shows that entropic effects contribute to finding and repairing potentially lethal double-strand breaks in DNA by increasing the mobility of the broken ends, favouring their juxtaposition for repair. Signaling pathways are strongly influenced by crowding, which favours a processive mode of response (consecutive reactions without releasing substrates. This new information contributes to understanding the sometimes counter

  1. Advances in atomic spectroscopy

    CERN Document Server

    Sneddon, J

    1998-01-01

    This volume continues the series'' cutting-edge reviews on developments in this field. Since its invention in the 1920s, electrostatic precipitation has been extensively used in industrial hygiene to remove dust and particulate matter from gases before entering the atmosphere. This combination of electrostatic precipitation is reported upon in the first chapter. Following this, chapter two reviews recent advances in the area of chemical modification in electrothermal atomization. Chapter three consists of a review which deal with advances and uses of electrothermal atomization atomic absorption spectrometry. Flow injection atomic spectroscopy has developed rapidly in recent years and after a general introduction, various aspects of this technique are looked at in chapter four. Finally, in chapter five the use of various spectrometric techniques for the determination of mercury are described.

  2. Atomic and Molecular Interactions

    International Nuclear Information System (INIS)

    The Gordon Research Conference (GRC) on Atomic and Molecular Interactions was held at Roger Williams University, Bristol, RI. Emphasis was placed on current unpublished research and discussion of the future target areas in this field

  3. Atomic Interferometry Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Vertical cavity surface emitting lasers (VCSELs) is a new technology which can be used for developing high performance laser components for atom-based sensors...

  4. Atom chip gravimeter

    Science.gov (United States)

    Schubert, Christian; Abend, Sven; Gebbe, Martina; Gersemann, Matthias; Ahlers, Holger; Müntinga, Hauke; Matthias, Jonas; Sahelgozin, Maral; Herr, Waldemar; Lämmerzahl, Claus; Ertmer, Wolfgang; Rasel, Ernst

    2016-04-01

    Atom interferometry has developed into a tool for measuring rotations [1], accelerations [2], and testing fundamental physics [3]. Gravimeters based on laser cooled atoms demonstrated residual uncertainties of few microgal [2,4] and were simplified for field applications [5]. Atomic gravimeters rely on the interference of matter waves which are coherently manipulated by laser light fields. The latter can be interpreted as rulers to which the position of the atoms is compared. At three points in time separated by a free evolution, the light fields are pulsed onto the atoms. First, a coherent superposition of two momentum states is produced, then the momentum is inverted, and finally the two trajectories are recombined. Depending on the acceleration the atoms experienced, the number of atoms detected in the output ports will change. Consequently, the acceleration can be determined from the output signal. The laser cooled atoms with microkelvin temperatures used in state-of-the-art gravimeters impose limits on the accuracy [4]. Therefore, ultra-cold atoms generated by Bose-Einstein condensation and delta-kick collimation [6,7] are expected to be the key for further improvements. These sources suffered from a low flux implying an incompatible noise floor, but a competitive performance was demonstrated recently with atom chips [8]. In the compact and robust setup constructed for operation in the drop tower [6] we demonstrated all steps necessary for an atom chip gravimeter with Bose-Einstein condensates in a ground based operation. We will discuss the principle of operation, the current performance, and the perspectives to supersede the state of the art. The authors thank the QUANTUS cooperation for contributions to the drop tower project in the earlier stages. This work is supported by the German Space Agency (DLR) with funds provided by the Federal Ministry for Economic Affairs and Energy (BMWi) due to an enactment of the German Bundestag under grant numbers DLR 50WM

  5. Topics in atomic physics

    CERN Document Server

    Burkhardt, Charles E

    2006-01-01

    The study of atomic physics propelled us into the quantum age in the early twentieth century and carried us into the twenty-first century with a wealth of new and, in some cases, unexplained phenomena. Topics in Atomic Physics provides a foundation for students to begin research in modern atomic physics. It can also serve as a reference because it contains material that is not easily located in other sources. A distinguishing feature is the thorough exposition of the quantum mechanical hydrogen atom using both the traditional formulation and an alternative treatment not usually found in textbooks. The alternative treatment exploits the preeminent nature of the pure Coulomb potential and places the Lenz vector operator on an equal footing with other operators corresponding to classically conserved quantities. A number of difficult to find proofs and derivations are included as is development of operator formalism that permits facile solution of the Stark effect in hydrogen. Discussion of the classical hydrogen...

  6. Hirshfeld atom refinement.

    Science.gov (United States)

    Capelli, Silvia C; Bürgi, Hans-Beat; Dittrich, Birger; Grabowsky, Simon; Jayatilaka, Dylan

    2014-09-01

    Hirshfeld atom refinement (HAR) is a method which determines structural parameters from single-crystal X-ray diffraction data by using an aspherical atom partitioning of tailor-made ab initio quantum mechanical molecular electron densities without any further approximation. Here the original HAR method is extended by implementing an iterative procedure of successive cycles of electron density calculations, Hirshfeld atom scattering factor calculations and structural least-squares refinements, repeated until convergence. The importance of this iterative procedure is illustrated via the example of crystalline ammonia. The new HAR method is then applied to X-ray diffraction data of the dipeptide Gly-l-Ala measured at 12, 50, 100, 150, 220 and 295 K, using Hartree-Fock and BLYP density functional theory electron densities and three different basis sets. All positions and anisotropic displacement parameters (ADPs) are freely refined without constraints or restraints - even those for hydrogen atoms. The results are systematically compared with those from neutron diffraction experiments at the temperatures 12, 50, 150 and 295 K. Although non-hydrogen-atom ADPs differ by up to three combined standard uncertainties (csu's), all other structural parameters agree within less than 2 csu's. Using our best calculations (BLYP/cc-pVTZ, recommended for organic molecules), the accuracy of determining bond lengths involving hydrogen atoms from HAR is better than 0.009 Å for temperatures of 150 K or below; for hydrogen-atom ADPs it is better than 0.006 Å(2) as judged from the mean absolute X-ray minus neutron differences. These results are among the best ever obtained. Remarkably, the precision of determining bond lengths and ADPs for the hydrogen atoms from the HAR procedure is comparable with that from the neutron measurements - an outcome which is obtained with a routinely achievable resolution of the X-ray data of 0.65 Å.

  7. Dangerous Energy : Atomic

    International Nuclear Information System (INIS)

    This book describes the disaster in Chernobyl, Russia. Through the accident It reveals the dangerous nuclear energy with a lot of problems on the nuclear power plants which includes four reasons about propelling development of atomic and criticism about that, eight reasons against development of atomic, the problem in 11 -12 nuclear power plant, the movement of antagonism towards nuclear waste in Anmyon island, cases of antinuclear in foreign country and building of new energy system.

  8. Atom laser divergence

    OpenAIRE

    Le Coq, Yann; Thywissen, Joseph H.; Rangwala, Sadiq A.; Gerbier, Fabrice; Richard, Simon; Delannoy, Guillaume; Bouyer, Philippe; Aspect, Alain

    2001-01-01

    We measure the angular divergence of a quasi-continuous, rf-outcoupled, free-falling atom laser as a function of the outcoupling frequency. The data is compared to a Gaussian-beam model of laser propagation that generalizes the standard formalism of photonic lasers. Our treatment includes diffraction, magnetic lensing, and interaction between the atom laser and the condensate. We find that the dominant source of divergence is the condensate-laser interaction.

  9. Guided Quasicontinuous Atom Laser

    OpenAIRE

    Guerin, William; Riou, Jean-Félix; Gaebler, John,; Josse, Vincent; Bouyer, Philippe; Aspect, Alain

    2006-01-01

    version published in Phys. Rev. Lett. 97, 200402 (2006) International audience We report the first realization of a guided quasicontinuous atom laser by rf outcoupling a Bose-Einstein condensate from a hybrid optomagnetic trap into a horizontal atomic waveguide. This configuration allows us to cancel the acceleration due to gravity and keep the de Broglie wavelength constant at 0.5 µm during 0.1 s of propagation. We also show that our configuration, equivalent to pigtailing an optical f...

  10. Metal atomization spray nozzle

    Science.gov (United States)

    Huxford, Theodore J.

    1993-01-01

    A spray nozzle for a magnetohydrodynamic atomization apparatus has a feed passage for molten metal and a pair of spray electrodes mounted in the feed passage. The electrodes, diverging surfaces which define a nozzle throat and diverge at an acute angle from the throat. Current passes through molten metal when fed through the throat which creates the Lorentz force necessary to provide atomization of the molten metal.

  11. Atoms, molecules & elements

    CERN Document Server

    Graybill, George

    2007-01-01

    Young scientists will be thrilled to explore the invisible world of atoms, molecules and elements. Our resource provides ready-to-use information and activities for remedial students using simplified language and vocabulary. Students will label each part of the atom, learn what compounds are, and explore the patterns in the periodic table of elements to find calcium (Ca), chlorine (Cl), and helium (He) through hands-on activities.

  12. Theoretical atomic collision physics

    Energy Technology Data Exchange (ETDEWEB)

    Lane, N.F. (Rice Univ., Houston, TX (USA) Rice Univ., Houston, TX (USA). Quantum Inst.)

    1990-01-01

    The theoretical atomic physics at Rice University focuses on obtaining a better understanding of the mechanisms that control inelastic collisions between excited atoms and atoms, molecules and ions. Particular attention is given to systems and processes that are of potential importance to advanced energy technologies. In the current year, significant progress has been made in quantitative studies of: quenching of low-Rydberg Na atoms in thermal energy collisions with He, Ne and Ar atoms; selective excitation resulting from charge transfer in collisions of highly stripped ions of He, Li, C, and with Li, Na and He atoms and H{sub 2} molecules at keV energies; differential elastic and single, and double electron transfer in He{sup ++} collisions with He at keV energies; inelastic electron-transfer in ultra-low-energy-energy (T=8 to 80K) collisions between {sup 3}He{sup +} and {sup 4}He and {sup 4}He{sup +} and {sup 3}He; a formalism for ionization by electron impact of ions in dense, high temperature plasmas.

  13. Antiproton Production in 11.5 A GeV/c Au+Pb Nucleus-Nucleus Collisions

    OpenAIRE

    E687 Collaboration; al, T. A. Armstrong et

    1997-01-01

    We present the first results from the E864 collaboration on the production of antiprotons in 10% central 11.5 A GeV/c Au+Pb nucleus collisions at the Brookhaven AGS. We report invariant multiplicities for antiproton production in the kinematic region 1.4

  14. ARGININE VASOPRESSIN GENE EXPRESSION IN SUPRAOPTIC NUCLEUS AND PARAVENTRICULAR NUCLEUS OF HYPOTHALAMOUS FOLLOWING CEREBRAL ISCHEMIA AND REPERFUSION

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Background. Our previous studies indicated that the increased arginine vasopressin(AVP) in ischemic brain regions of gerbils could exacerbate the ischemic brain edema. This experiments is further clarify the relation between AVP and cerebral ischemia at the molecular level. Methods. The contents of AVP, AVP mRNA, AVP immunoreactive(ir) neurons in supraoptic nucleus(SON)and paraventricular nucleus(PVN) after cerebral ischemia and reperfusion were respectively determined by radioim-munoassay(RIA), immunocytochemistry( Ⅱ C), situ hybridization and computed image pattem analysis. Results. The contents of AVP in SON, PVN were increased, and the AVP ir positive neurons in SON and PVN were also significantly increased as compared with the controls after ischemia and reperfusion. And there were very light staining of AVP ir positive neurons in the other brain areas such as suprachiasmatic nucleus (SC) and periven-tricular hypothalamic nucleus (PE), but these have no significant changes as compared with the controls. During dif-ferent periods of cerebral ischemia (30~ 120 min) and reperfusion (30 min), AVP mRNA expression in SON and PVN were more markedly increased than the controls. Condusions. The transcription of AVP gene elevated, then promoting synthesis and release of AVP in SON,PVN. Under the specific condition of cerebral ischemia and repeffusion, the activity and contents of central AVP in-creased abnormally is one of the important factors which causes ischemia brain damage.

  15. Pair production and annihilation via nuclear resonances in atoms and ions

    Energy Technology Data Exchange (ETDEWEB)

    Belov, Nikolay A.; Harman, Zoltan [Max Planck Institute for Nuclear Physics, Heidelberg (Germany)

    2014-07-01

    Processes connected with pair production and annihilation in atoms and ions are theoretically investigated. These include nuclear excitation by resonance positron annihilation (NERPA) and nuclear-resonant e{sup -}e{sup +} pair creation in heavy ion collisions. Possible experimental schemes are put forward for the observation of these reactions. NERPA is an alternative channel of positron-matter interaction, with potential relevance in cosmic ray studies, medical positron emission tomography research, in experimental investigations of nuclear chain reactions, and in star evolution simulations. It also constitutes a novel means for the energy-selective excitation of nuclei. In heavy ion collisions, the Coulomb-excited nucleus may decay by a creation of a free-free or bound-free e{sup -}e{sup +} pair. Thus, it is an additional, resonant channel of pair creation in nucleus-nucleus collisions, an experimental investigation of which is projected at the FAIR facility.

  16. Projections from the raphe nuclei to the suprachiasmatic nucleus of the rat

    DEFF Research Database (Denmark)

    Hay-Schmidt, Anders; Vrang, N.; Larsen, P.J.;

    2003-01-01

    Hypothalamus, Circadian rhythm, Serotonin, Nucleus, Neuronal connections, Phaseolus vulgaris-leucoagglutinin (PHA-L), Cholera toxin (ChB)......Hypothalamus, Circadian rhythm, Serotonin, Nucleus, Neuronal connections, Phaseolus vulgaris-leucoagglutinin (PHA-L), Cholera toxin (ChB)...

  17. DMPD: TGF-beta signaling from receptors to the nucleus. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 10611754 TGF-beta signaling from receptors to the nucleus. Roberts AB. Microbes Inf...leus. PubmedID 10611754 Title TGF-beta signaling from receptors to the nucleus. Authors Roberts AB. Publicat

  18. Atomic 'After Effects' Following 181Hfβ--Decay

    International Nuclear Information System (INIS)

    Strong evidence of atomic 'after effects' following β--decay of 181Hf was observed from perturbed angular correlation (PAC) studies in different viscous and non-viscous molecular solutions and in ionic as well as non-ionic solutions. In non-viscous acetone and H2O solutions, the PAC spectra have been found to be completely different to what was expected considering molecular motions in these media. Similarly, in the glycerol-H2O system, PAC spectra remain significantly unchanged with the change of viscosity indicating that molecular motions are not reflected in these media. Rather, perturbations from the interaction of the nucleus-excited atomic state, which was so far considered to be absent for 181Hf β--decay, have been found to be dominant. The atomic shell recovery times inmolecular liquids have been found to be in the range 50-150 nsec. In insulating solid HfCl4 medium, however, the PAC spectrum indicates that the atomic shell following 181Hf β--decay remains unchanged within the lifetime of the intermediate state. The lifetime for the 615 keV level has been remeasured and a value of T1/2=12.1±0.1 nsec only has been obtained. This value, although in strong disagreement with the earlier reported value (17.83 μsec), helps explain atomic 'after effects' in 181Hf β--decay.

  19. Effective potentials for atom-atom interaction at low temperatures

    OpenAIRE

    Gao, Bo

    2002-01-01

    We discuss the concept and design of effective atom-atom potentials that accurately describe any physical processes involving only states around the threshold. The existence of such potentials gives hope to a quantitative, and systematic, understanding of quantum few-atom and quantum many-atom systems at relatively low temperatures.

  20. Teleportation of Atomic States for Atoms in a Lambda Configuration

    CERN Document Server

    Guerra, E S

    2004-01-01

    In this article we discuss a scheme of teleportation of atomic states making use of three-level lambda atoms. The experimental realization proposed makes use of cavity QED involving the interaction of Rydberg atoms with a micromaser cavity prepared in a coherent state. We start presenting a scheme to prepare atomic EPR states involving two-level atoms via the interaction of these atoms with a cavity. In our scheme the cavity and some atoms play the role of auxiliary systems used to achieve the teleportation.

  1. Pedunculopontine Nucleus Gamma Band Activity-Preconscious Awareness, Waking, and REM Sleep

    OpenAIRE

    Urbano, Francisco J.; Stasia M D'Onofrio; Brennon R Luster; Paige B Beck; James Robert Hyde; Veronica eBisagno; Edgar eGarcia-Rill

    2014-01-01

    The pedunculopontine nucleus (PPN) is a major component of the reticular activating system (RAS) that regulates waking and REM sleep, states of high frequency EEG activity. Recently, we described the presence of high threshold, voltage-dependent N- and P/Q-type calcium channels in RAS nuclei that subserve gamma band oscillations in the mesopontine pedunculopontine nucleus (PPN), intralaminar parafascicular nucleus (Pf), and pontine Subcoeruleus nucleus dorsalis (SubCD). Cortical gamma band ...

  2. Capsulotomy and hydroprocedures for nucleus prolapse in manual small incision cataract surgery

    OpenAIRE

    Venkatesh Rengaraj; Veena Kannusamy; Ravindran Ravilla

    2009-01-01

    Manual small incision cataract surgery (MSICS) involves the manual removal of nucleus through a scleral tunnel. To achieve 100% success every time, one has to do a good capsulotomy and should master the technique to prolapse the nucleus into anterior chamber. During conversion from extracapsular cataract surgery to MSICS, one can perform a can-opener capsulotomy and prolapse the nucleus. However, it is safer and better to perform a capsulorrhexis and hydroprolapse the nucleus, as it ma...

  3. Energy Wave Model of Atom

    Institute of Scientific and Technical Information of China (English)

    伍细如

    2015-01-01

    proton emits energy wave, electron could sits any position away from nucleus, but be the most stable just when it sits at the trough of energy wave, and this position accords with Bohr radius and Schr?dinger equation.

  4. Single-atom spintronics

    Institute of Scientific and Technical Information of China (English)

    Susan Z. HUA; Matthew R. SULLIVAN; Jason N. ARMSTRONG

    2006-01-01

    Recent work on magnetic quantum point contacts (QPCs) was discussed. Complete magnetoresistance loops across Co QPCs as small as a single atom was measured. The remarkable feature of these QPCs is the rapid oscillatory decay in magnetoresistance with the increase of contact size. In addition,stepwise or quantum magnetoresistance loops are observed,resulting from varying transmission probability of the available discrete conductance channels because the sample is cycled between the ferromagnetic (F) and antiferromagnetic (AF) aligned states. Quantized conductance combined with spin dependent transmission of electron waves gives rise to a multi-channel system with a quantum domain wall acting as a valve,i.e.,a quantum spin-valve. Behavior of a few-atom QPC is built on the behavior of a single-atom QPC and hence the summarization of results as 'single-atom spintronics'. An evolutionary trace of spin-dependent electron transmission from a single atom to bulk is provided,the requisite hallmarks of artefact-free magnetoresistance is established across a QPC - stepwise or quantum magnetoresistance loops and size dependent oscillatory magnetoresistance.

  5. Universal bosonic tetramers of dimer-atom-atom structure

    OpenAIRE

    Deltuva, A

    2012-01-01

    Unstable four-boson states having an approximate dimer-atom-atom structure are studied using momentum-space integral equations for the four-particle transition operators. For a given Efimov trimer the universal properties of the lowest associated tetramer are determined. The impact of this tetramer on the atom-trimer and dimer-dimer collisions is analyzed. The reliability of the three-body dimer-atom-atom model is studied.

  6. The Nucleus of Translating as One Critical Concern in Translation Pedagogy and Assessment.

    Science.gov (United States)

    Hu, Helen Chau

    1999-01-01

    Studies the translation of nonliterary texts. The objective is to associate the nucleus of translating with the value of a source-language text, advancing the claim that appropriately translating the nucleus is among the most important concerns, and to propose an approach to assessment for translation quality based on how the nucleus is rendered.…

  7. File list: His.Neu.50.AllAg.Caudate_Nucleus [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Neu.50.AllAg.Caudate_Nucleus hg19 Histone Neural Caudate Nucleus SRX998285,SRX9...98283 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Neu.50.AllAg.Caudate_Nucleus.bed ...

  8. File list: ALL.Neu.05.AllAg.Caudate_Nucleus [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  9. File list: His.Neu.20.AllAg.Caudate_Nucleus [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Neu.20.AllAg.Caudate_Nucleus hg19 Histone Neural Caudate Nucleus SRX998285,SRX9...98283 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Neu.20.AllAg.Caudate_Nucleus.bed ...

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    Lifescience Database Archive (English)

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  11. File list: His.Neu.10.AllAg.Caudate_Nucleus [Chip-atlas[Archive

    Lifescience Database Archive (English)

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    Lifescience Database Archive (English)

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    Lifescience Database Archive (English)

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  14. File list: ALL.Neu.50.AllAg.Caudate_Nucleus [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  15. File list: ALL.Neu.20.AllAg.Nucleus_Accumbens [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  16. File list: NoD.Neu.50.AllAg.Nucleus_Accumbens [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available NoD.Neu.50.AllAg.Nucleus_Accumbens mm9 No description Neural Nucleus Accumbens http...://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/NoD.Neu.50.AllAg.Nucleus_Accumbens.bed ...

  17. File list: Pol.Neu.10.AllAg.Nucleus_Accumbens [Chip-atlas[Archive

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    Full Text Available Pol.Neu.10.AllAg.Nucleus_Accumbens mm9 RNA polymerase Neural Nucleus Accumbens SRX2...09217,SRX209216,SRX209214,SRX209218,SRX209215,SRX209213 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Pol.Neu.10.AllAg.Nucleus_Accumbens.bed ...

  18. File list: InP.Neu.20.AllAg.Nucleus_Accumbens [Chip-atlas[Archive

    Lifescience Database Archive (English)

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    Lifescience Database Archive (English)

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  20. File list: Oth.Neu.05.AllAg.Nucleus_Accumbens [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  1. File list: Oth.Neu.10.AllAg.Nucleus_Accumbens [Chip-atlas[Archive

    Lifescience Database Archive (English)

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    Lifescience Database Archive (English)

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    Lifescience Database Archive (English)

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  4. File list: His.Neu.50.AllAg.Nucleus_Accumbens [Chip-atlas[Archive

    Lifescience Database Archive (English)

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    Lifescience Database Archive (English)

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    Lifescience Database Archive (English)

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  8. File list: His.Neu.10.AllAg.Nucleus_Accumbens [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  10. File list: Pol.Neu.50.AllAg.Nucleus_Accumbens [Chip-atlas[Archive

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    Lifescience Database Archive (English)

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    Lifescience Database Archive (English)

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  1. File list: Pol.Neu.05.AllAg.Nucleus_Accumbens [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  2. Triple F - A Comet Nucleus Sample Return Mission

    Science.gov (United States)

    Kueppers, Michael; Keller, H. U.; Kuehrt, E.; A'Hearn, M. F.; Altwegg, K.; Bertrand, R.; Busemann, H.; Capria, M. T.; Colangeli, L.; Davidsson, B.; Ehrenfreund, P.; Knollenberg, J.; Mottola, S.; Weiss, P.; Zolensky, M.; Akim, E.; Basilevsky, A.; Galimov, E.; Gerasimov, M.; Korablev, O.; Charnley, S.; Nittler, L. R.; Sandford, S.; Weissman, P.

    2008-01-01

    The Triple F (Fresh From the Fridge) mission, a Comet Nucleus Sample Return, has been proposed to ESA's Cosmic Vision program. A sample return from a comet enables us to reach the ultimate goal of cometary research. Since comets are the least processed bodies in the solar system, the proposal goes far beyond cometary science topics (like the explanation of cometary activity) and delivers invaluable information about the formation of the solar system and the interstellar molecular cloud from which it formed. The proposed mission would extract three sample cores of the upper 50 cm from three locations on a cometary nucleus and return them cooled to Earth for analysis in the laboratory. The simple mission concept with a touch-andgo sampling by a single spacecraft was proposed as an M-class mission in collaboration with the Russian space agency ROSCOSMOS.

  3. Efficient And Portable SDR Waveform Development: The Nucleus Concept

    CERN Document Server

    Ramakrishnan, Venkatesh; Kempf, Torsten; Kammler, David; Ascheid, Gerd; Meyr, Heinrich; Adrat, Marc; Antweiler, Markus

    2009-01-01

    Future wireless communication systems should be flexible to support different waveforms (WFs) and be cognitive to sense the environment and tune themselves. This has lead to tremendous interest in software defined radios (SDRs). Constraints like throughput, latency and low energy demand high implementation efficiency. The tradeoff of going for a highly efficient implementation is the increase of porting effort to a new hardware (HW) platform. In this paper, we propose a novel concept for WF development, the Nucleus concept, that exploits the common structure in various wireless signal processing algorithms and provides a way for efficient and portable implementation. Tool assisted WF mapping and exploration is done efficiently by propagating the implementation and interface properties of Nuclei. The Nucleus concept aims at providing software flexibility with high level programmability, but at the same time limiting HW flexibility to maximize area and energy efficiency.

  4. Theoretical description of the decay chain of the nucleus 294118

    Science.gov (United States)

    Sobiczewski, Adam

    2016-09-01

    The decay chain of the nucleus 294118, the heaviest nucleus observed (at JINR-Dubna) up to now, is analyzed theoretically. The α-decay energies {Q}α , the α-decay and the spontaneous-fission half-lives, {T}α and {T}{{sf}}, are studied. The analysis of the α decay is based on a phenomenological model using only three parameters. The calculations are performed in three variants using masses obtained with three nuclear-mass models accurately describing masses of heaviest nuclei. The experimental {Q}α energies are reconstructed with the average of the absolute values of the discrepancies: 180 keV, 270 keV and 290 keV, in the three variants considered. Measured half-lives {T}α are reproduced within the average ratios: 2.9, 9.8 and 5.2 in these variants.

  5. Antiproton-Nucleus Interaction and Coulomb Effect at High Energies

    Institute of Scientific and Technical Information of China (English)

    ZHOU Li-Juan; WU Qing; GU Yun-Ting; MA Wei-Xing; TAN Zhen-Qiang; HU Zhao-Hui

    2005-01-01

    The Coulomb effect in high energy antiproton-nucleus elastic and inelastic scattering from 12C and 16O is studied in the framework of Glauber multiple scattering theory for five kinetic energies ranged from 0.23 to 1.83 GeV.A microscopic shell-model nuclear wave functions, Woods-Saxon single-particle wave functions, and experimental pN amplitudes are used in the calculations. The results show that the Coulomb effect is of paramount importance for filling up the dips of differential cross sections. We claim that the present result for inelastic scattering of antiproton-12C is sufficiently reliable to be a guide for measurements in the very near future. We also believe that antiproton nucleus elastic and inelastic scattering may produce new information on both the nuclear structure and the antinucleon-nucleon interaction, in particular the p-neutron interaction.

  6. $K^+$-nucleus potentials from $K^+$-nucleon amplitudes

    CERN Document Server

    Friedman, E

    2016-01-01

    Optical potentials for $K^+$-nucleus interactions are constructed from $K^+$-nucleon amplitudes using recently developed algorithm based on $K^+$-N kinematics in the nuclear medium. With the deep penetration of $K^+$ mesons into the nucleus at momenta below 800~MeV/c it is possible to test this approach with greater sensitivity than hitherto done with $K^-$ and pions. The energy-dependence of experimental reaction and total cross sections on nuclei is better reproduced with this approach compared to fixed-energy amplitudes. The inclusion of Pauli correlations in the medium also improves the agreement between calculation and experiment. The absolute scale of the cross sections is reproduced very well for $^6$Li but for C, Si and Ca calculated cross sections are (23$\\pm4$)\\% smaller than experiment, in agreement with earlier analyses. Two phenomenological models that produce such missing strength suggest that the imaginary part of the potential needs about 40\\% enhancement.

  7. The identification of musical instruments through nucleus cochlear implants.

    Science.gov (United States)

    Grasmeder, M L; Lutman, M E

    2006-09-01

    In this study, self-reported ability to recognize musical instruments was investigated by means of a questionnaire, which was sent to a group of adult Nucleus cochlear implant users and a group of normally hearing subjects. In addition, spectrograms and electrodograms were produced and analysed for samples of music played on 10 different musical instruments. Self-reported ability to recognize some instruments was poor in the group of implant users, particularly for the saxophone, tuba and clarinet. Electrodograms showed that these instruments could only be identified using distorted spectral information or reduced temporal information. Other instruments, such as the drum and piano, could be identified using temporal information. Limited spectral resolution makes the recognition of musical instruments difficult for Nucleus implant users.

  8. K+-nucleus potentials from K+-nucleon amplitudes

    Science.gov (United States)

    Friedman, E.

    2016-10-01

    Optical potentials for K+-nucleus interactions are constructed from K+-nucleon amplitudes using recently developed algorithm based on K+-N kinematics in the nuclear medium. With the deep penetration of K+ mesons into the nucleus at momenta below 800 MeV / c it is possible to test this approach with greater sensitivity than hitherto done with K- and pions. The energy-dependence of experimental reaction and total cross sections on nuclei is better reproduced with this approach compared to fixed-energy amplitudes. The inclusion of Pauli correlations in the medium also improves the agreement between calculation and experiment. The absolute scale of the cross sections is reproduced very well for 6Li but for C, Si and Ca calculated cross sections are (23 ± 4)% smaller than experiment, in agreement with earlier analyses. Two phenomenological models that produce such missing strength suggest that the imaginary part of the potential needs about 40% enhancement.

  9. Electromagnetic properties of the Beryllium-11 nucleus in Halo EFT

    Directory of Open Access Journals (Sweden)

    Hammer H.-W.

    2010-04-01

    Full Text Available We compute electromagnetic properties of the Beryllium-11 nucleus using an effective field theory that exploits the separation of scales in this halo system. We fix the parameters of the EFT from measured data on levels and scattering lengths in the 10Be plus neutron system. We then obtain predictions for the B(E1 strength of the 1/2+ to 1/2− transition in the 11Be nucleus. We also compute the charge radius of the ground state of 11Be. Agreement with experiment within the expected accuracy of a leading-order computation in this EFT is obtained. We also indicate how higher-order corrections that affect both s-wave and p-wave 10 Be-neutron interactions will affect our results.

  10. Maps of interaural delay in the owl's nucleus laminaris.

    Science.gov (United States)

    Carr, Catherine E; Shah, Sahil; McColgan, Thomas; Ashida, Go; Kuokkanen, Paula T; Brill, Sandra; Kempter, Richard; Wagner, Hermann

    2015-09-01

    Axons from the nucleus magnocellularis form a presynaptic map of interaural time differences (ITDs) in the nucleus laminaris (NL). These inputs generate a field potential that varies systematically with recording position and can be used to measure the map of ITDs. In the barn owl, the representation of best ITD shifts with mediolateral position in NL, so as to form continuous, smoothly overlapping maps of ITD with iso-ITD contours that are not parallel to the NL border. Frontal space (0°) is, however, represented throughout and thus overrepresented with respect to the periphery. Measurements of presynaptic conduction delay, combined with a model of delay line conduction velocity, reveal that conduction delays can account for the mediolateral shifts in the map of ITD. PMID:26224776

  11. Determination of the {\\eta}'-nucleus optical potential

    CERN Document Server

    Nanova, M; Paryev, E Ya; Bayadilov, D; Bantes, B; Beck, R; Beloglazov, Y A; Böse, S; Brinkmann, K -T; Challand, Th; Crede, V; Dahlke, T; Dietz, F; Drexler, P; Eberhardt, H; Elsner, D; Ewald, R; Fornet-Ponse, K; Friedrich, S; Frommberger, F; Funke, Ch; Gottschall, M; Gridnev, A; Grüner, M; Gutz, E; Hammann, Ch; Hammann, D; Hannappel, J; Hartmann, J; Hillert, W; Hoffmeister, P; Honisch, Ch; Jaegle, I; Kaiser, D; Kalinowsky, H; Kammer, S; Keshelashvili, I; Kleber, V; Klein, F; Klempt, E; Krusche, B; Lang, M; Lopatin, I V; Maghrbi, Y; Makonyi, K; Müller, J; Odenthal, T; Piontek, D; Schaepe, S; Schmidt, Ch; Schmieden, H; Schmitz, R; Seifen, T; Thiel, A; Thoma, U; van Pee, H; Walther, D; Wendel, Ch; Wiedner, U; Wilson, A; Winnebeck, A; Zenke, F

    2013-01-01

    The excitation function and momentum distribution of $\\eta^\\prime$ mesons have been measured in photon induced reactions on $^{12}{}$C in the energy range of 1250-2600 MeV. The experiment was performed with tagged photon beams from the ELSA electron accelerator using the Crystal Barrel and TAPS detectors. The data are compared to model calculations to extract information on the sign and magnitude of the real part of the $\\eta^\\prime$-nucleus potential. Within the model, the comparison indicates an attractive potential of -($37 \\pm 10(stat)\\pm10(syst)$) MeV depth at normal nuclear matter density. Since the modulus of this depth is larger than the modulus of the imaginary part of the $\\eta^\\prime$-nucleus potential of -($10\\pm2.5$) MeV, determined by transparency ratio measurements, a search for resolved $\\eta^\\prime$-bound states appears promising.

  12. Coulomb Excitation of the N = 50 nucleus 80Zn

    International Nuclear Information System (INIS)

    Neutron rich Zinc isotopes, including the N = 50 nucleus 80Zn, were produced and post-accelerated at the Radioactive Ion Beam (RIB) facility REX-ISOLDE (CERN). Low-energy Coulomb excitation was induced on these isotopes after post-acceleration, yielding B(E2) strengths to the first excited 2+ states. For the first time, an excited state in 80Zn was observed and the 21+ state in 78Zn was established. The measured B(E2,21+→01+) values are compared to two sets of large scale shell model calculations. Both calculations reproduce the observed B(E2) systematics for the full Zinc isotopic chain. The results for N = 50 isotones indicate a good N = 50 shell closure and a strong Z = 28 proton core polarization. The new results serve as benchmarks to establish theoretical models, predicting the nuclear properties of the doubly magic nucleus 78Ni

  13. Pairing reentrance in warm rotating $^{104}$Pd nucleus

    CERN Document Server

    Hung, N Quang; Agrawal, B K; Datar, V M; Mitra, A; Chakrabarty, D R

    2015-01-01

    Pairing reentrance phenomenon in the warm rotating $^{104}$Pd nucleus is studied within the Bardeen-Cooper-Schrieffer (BCS)-based approach (the FTBCS1). The theory takes into account the effect of quasiparticle number fluctuations on the pairing field at finite temperature and angular momentum within the pairing model plus noncollective rotation along the symmetry axis. The numerical calculations for the pairing gaps and nuclear level densities (NLD), of which an anomalous enhancement has been experimentally observed at low excitation energy $E^*$ and high angular momentum $J$, show that the pairing reentrance is seen in the behavior of pairing gap obtained within the FTBCS1 at low $E$ and high $J$. This leads to the enhancement of the FTBCS1 level densities, in good agreement with the experimental observation. This agreement indicates that the observed enhancement of the NLD might be the first experimental detection of the pairing reentrance in a finite nucleus.

  14. Collective effects of supernova explosions in a starbusrst nucleus

    International Nuclear Information System (INIS)

    The collective effects of supernova (SN) explosions in the nucleus of a starburst galaxy are studied. It is shown that a large wind bubble with the size of a few hundred parsecs in the nucleus of a starburst galaxy will expand for SN explosion rates of 0.1 per year of greater. The bubble gradually elongates due to density stratification. Finally, the shell breaks near the top and the hot matter flows through the cylindrical shell up to 1--2 kpc above the disk plane. The authors discuss the x-ray emission in the halos of galaxies such as M82 and NGC 253 and the distribution of molecular gas in such galaxies in relation to the starburst phenomenon

  15. Neutral current neutrino-nucleus interactions at intermediate energies

    CERN Document Server

    Leitner, T; Mosel, U

    2006-01-01

    We have extended our model for charged current neutrino-nucleus interactions to neutral current reactions. For the elementary neutrino-nucleon interaction, we take into account quasielastic scattering, Delta excitation and the excitation of the resonances in the second resonance region. Our model for the neutrino-nucleus collisions includes in-medium effects such as Fermi motion, Pauli blocking, nuclear binding, and final-state interactions. They are implemented by means of the Giessen Boltzmann-Uehling-Uhlenbeck (GiBUU) coupled-channel transport model. This allows us to study exclusive channels, namely pion production and nucleon knockout. We find that final-state interactions modify considerably the distributions through rescattering, charge-exchange and absorption. Side-feeding induced by charge-exchange scattering is important in both cases. In the case of pions, there is a strong absorption associated with the in-medium pionless decay modes of the Delta, while nucleon knockout exhibits a considerable enh...

  16. Interpretation of Hund's multiplicity rule for the carbon atom.

    Science.gov (United States)

    Hongo, Kenta; Maezono, Ryo; Kawazoe, Yoshiyuki; Yasuhara, Hiroshi; Towler, M D; Needs, R J

    2004-10-15

    Hund's multiplicity rule is investigated for the carbon atom using quantum Monte Carlo methods. Our calculations give an accurate account of electronic correlation and obey the virial theorem to high accuracy. This allows us to obtain accurate values for each of the energy terms and therefore to give a convincing explanation of the mechanism by which Hund's rule operates in carbon. We find that the energy gain in the triplet with respect to the singlet state is due to the greater electron-nucleus attraction in the higher spin state, in accordance with Hartree-Fock calculations and studies including correlation. The method used here can easily be extended to heavier atoms. PMID:15473780

  17. Electron quantum dynamics in atom-ion interaction

    Science.gov (United States)

    Sabzyan, H.; Jenabi, M. J.

    2016-04-01

    Electron transfer (ET) process and its dependence on the system parameters are investigated by solving two-dimensional time-dependent Schrödinger equation numerically using split operator technique. Evolution of the electron wavepacket occurs from the one-electron species hydrogen atom to another bare nucleus of charge Z > 1. This evolution is quantified by partitioning the simulation box and defining regional densities belonging to the two nuclei of the system. It is found that the functional form of the time-variations of these regional densities and the extent of ET process depend strongly on the inter-nuclear distance and relative values of the nuclear charges, which define the potential energy surface governing the electron wavepacket evolution. Also, the initial electronic state of the single-electron atom has critical effect on this evolution and its consequent (partial) electron transfer depending on its spreading extent and orientation with respect to the inter-nuclear axis.

  18. A discrete variable representation for electron-hydrogen atom scattering

    Energy Technology Data Exchange (ETDEWEB)

    Gaucher, L.F.

    1994-08-01

    A discrete variable representation (DVR) suitable for treating the quantum scattering of a low energy electron from a hydrogen atom is presented. The benefits of DVR techniques (e.g. the removal of the requirement of calculating multidimensional potential energy matrix elements and the availability of iterative sparse matrix diagonalization/inversion algorithms) have for many years been applied successfully to studies of quantum molecular scattering. Unfortunately, the presence of a Coulomb singularity at the electrically unshielded center of a hydrogen atom requires high radial grid point densities in this region of the scattering coordinate, while the presence of finite kinetic energy in the asymptotic scattering electron also requires a sufficiently large radial grid point density at moderate distances from the nucleus. The constraints imposed by these two length scales have made application of current DVR methods to this scattering event difficult.

  19. Quantum magnetism through atomic assembly

    NARCIS (Netherlands)

    Spinelli, A.

    2015-01-01

    This thesis presents an experimental study of magnetic structures, composed of only a few atoms. Those structures are first built atom-by-atom and then locally probed, both with a low-temperature STM. The technique that we use to assemble them is vertical atom manipulation, while to study their phy

  20. Cardiovascular responses to hydrogen peroxide into the nucleus tractus solitarius

    OpenAIRE

    Cardoso, Leonardo Máximo; Colombari, Débora Simões Almeida; Menani, José V; Toney, Glenn M.; Chianca, Deoclécio Alves; Colombari, Eduardo

    2009-01-01

    The nucleus tractus solitarius (NTS), a major hindbrain area involved in cardiovascular regulation, receives primary afferent fibers from peripheral baroreceptors and chemoreceptors. Hydrogen peroxide (H2O2) is a relatively stable and diffusible reactive oxygen species (ROS), which acting centrally, may affect neural mechanisms. In the present study, we investigated effects of H2O2 alone or combined with the glutamatergic antagonist kynurenate into the NTS on mean arterial pressure (MAP) and ...

  1. Nucleus accumbens lesions modulate the effects of Methylphenidate

    OpenAIRE

    Podet, Adam; Lee, Min J.; Swann, Alan C.; Dafny, Nachum

    2010-01-01

    The psychostimulant methylphenidate (MPD, Ritalin) is the prescribed drug of choice for treatment of ADHD. In recent years, the diagnosis rate of ADHD has increased dramatically, as have the number of MPD prescriptions. Repeated exposure to psychostimulants produces behavioral sensitization in rats, an experimental indicator of a drug’s potential liability. In studies on cocaine and amphetamine, this effect has been reported to involve the nucleus accumbens (NAc), one of the nuclei belonging ...

  2. High-energy pion-nucleus elastic scattering

    OpenAIRE

    Chen, C. M.; Ernst, D. J.; Johnson, M B

    1992-01-01

    We investigate theoretical approaches to pion--nucleus elastic scattering at high energies (300 $\\le T_\\pi \\le$ 1 GeV). A ``model--exact'' calculation of the lowest--order microscopic optical model, carried out in momentum space and including the full Fermi averaging integration, a realistic off--shell pion--nucleon scattering amplitude and fully covariant kinematics, is used to calibrate a much simpler theory. The simpler theory utilizes a local optical potential with an eikonal propagator a...

  3. The Ionization Source in the Nucleus of M84

    Science.gov (United States)

    Bower, G. A.; Green, R. F.; Quillen, A. C.; Danks, A.; Malumuth, E. M.; Gull, T.; Woodgate, B.; Hutchings, J.; Joseph, C.; Kaiser, M. E.

    2000-01-01

    We have obtained new Hubble Space Telescope (HST) observations of M84, a nearby massive elliptical galaxy whose nucleus contains a approximately 1.5 X 10(exp 9) solar mass dark compact object, which presumably is a supermassive black hole. Our Space Telescope Imaging Spectrograph (STIS) spectrum provides the first clear detection of emission lines in the blue (e.g., [0 II] lambda 3727, HBeta and [0 III] lambda lambda4959,5007), which arise from a compact region approximately 0".28 across centered on the nucleus. Our Near Infrared Camera and MultiObject Spectrometer (NICMOS) images exhibit the best view through the prominent dust lanes evident at optical wavelengths and provide a more accurate correction for the internal extinction. The relative fluxes of the emission lines we have detected in the blue together with those detected in the wavelength range 6295 - 6867 A by Bower et al. indicate that the gas at the nucleus is photoionized by a nonstellar process, instead of hot stars. Stellar absorption features from cool stars at the nucleus are very weak. We update the spectral energy distribution of the nuclear point source and find that although it is roughly flat in most bands, the optical to UV continuum is very red, similar to the spectral energy distribution of BL Lac. Thus, the nuclear point source seen in high-resolution optical images is not a star cluster but is instead a nonstellar source. Assuming isotropic emission from this source, we estimate that the ratio of bolometric luminosity to Eddington luminosity is about 5 x 10(exp -7). However, this could be underestimated if this source is a misaligned BL Lac object, which is a possibility suggested by the spectral energy distribution and the evidence of optical variability we describe.

  4. Three-dimensional organization of the human interphase nucleus.

    OpenAIRE

    Knoch, Tobias; Münkel, Christian; Waldeck, Waldemar; Langowski, Jörg

    2002-01-01

    textabstractDespite the successful linear sequencing of the human genome its three-dimensional structure is widely unknown, although it is important for gene regulation and replication. For a long time the interphase nucleus has been viewed as a 'spaghetti soup' of DNA without much internal structure, except during cell division. Only recently has it become apparent that chromosomes occupy distinct 'territories' also in interphase. Two models for the detailed folding of the 30 nm chromatin fi...

  5. The nucleus; Le noyau dans tous ses etats

    Energy Technology Data Exchange (ETDEWEB)

    Marano, S

    1998-10-01

    In 1911 E.Rutherford discovered the nucleus. Since then the nucleus has been investigated with more and more powerful tools but it remains the main field of study of nuclear physics. As it is impossible to take into account the interaction of all the nucleons, a theory based on the hypothesis that each nucleon undergoes an average interaction force has been set up. 2 representations have emerged: the Skyrme force and the Gogny force. Both representations match experimental results but are unable to describe fission yields or the multi-fragmentation of very hot nuclei. The mean-field theory can predict the shape of the nuclei according to its energy level. An experimental program involving the Vivitron accelerator and the Euroball detector is due to begin to validate it. By bombarding targets with exotic nuclei nuclear physicists detect new structures and test their collision models. About ten years ago nuclear halos were observed with lithium 11 nuclei. In this nucleus 2 neutrons move in a space larger than the nucleus itself. This discovery has triggered the elaboration of new theories based on nuclear clusters. At very high temperatures the mean-field theory predicts that nuclear matter acts as a fluid. Following the nuclei temperature different ways of decay appear: first evaporation then multi-fragmentation and vaporization. This ultimate stage occurs around 100 milliard celsius degree temperature when the nuclei decays in a multitude of light particles. Isomeric states are studied and could be seen as a way of storing energy. In a very pedagogical way this article gives information to understand the challenges that face nuclear physics today and highlights the contributions of Cea in this field. (A.C.)

  6. GlyT2+ Neurons in the Lateral Cerebellar Nucleus

    OpenAIRE

    Uusisaari, Marylka; Knöpfel, Thomas

    2009-01-01

    The deep cerebellar nuclei (DCN) are a major hub in the cerebellar circuitry but the functional classification of their neurons is incomplete. We have previously characterized three cell groups in the lateral cerebellar nucleus: large non-GABAergic neurons and two groups of smaller neurons, one of which express green fluorescence protein (GFP) in a GAD67/GFP mouse line and is therefore GABAergic. However, as a substantial number of glycinergic and glycine/GABA co-expressing neurons have been ...

  7. Cellular effects of swim stress in the dorsal raphe nucleus

    OpenAIRE

    Kirby, Lynn G.; Pan, Yu-Zhen; Freeman-Daniels, Emily; Rani, Shobha; Nunan, John D.; Akanwa, Adaure; Beck, Sheryl G

    2007-01-01

    Swim stress regulates forebrain 5-hydroxytryptamine (5-HT) release in a complex manner and its effects are initiated in the serotonergic dorsal raphe nucleus (DRN). The purpose of this study was to examine the effects of swim stress on the physiology of DRN neurons in conjunction with 5-HT immunohistochemistry. Basic membrane properties, 5-HT1A and 5-HT1B receptor-mediated responses and glutamatergic excitatory postsynaptic currents (EPSCs) were measured using whole-cell patch clamp technique...

  8. Nucleus accumbens core lesions enhance two-way active avoidance

    OpenAIRE

    Lichtenberg, Nina T.; Kashtelyan, Vadim; Burton, Amanda C.; Bissonette, Gregory B.; Roesch, Matthew R.

    2013-01-01

    The majority of work examining nucleus accumbens core (NAc) has focused on functions pertaining to behaviors guided by appetitive outcomes. These studies have pointed to NAc as being critical for motivating behavior toward desirable outcomes. For example, we have recently shown that lesions of NAc impaired performance on a reward-guided decision-making task that required rats to choose between differently valued rewards. Unfortunately, much less is known about the role that NAc plays in motiv...

  9. Total cross sections for neutron-nucleus scattering

    OpenAIRE

    Suryanarayana, S. V.; H. Naik; Ganesan, S; Kailas, S; Choudhury, R. K.; Kim, Guinyum

    2010-01-01

    Systematics of neutron scattering cross sections on various materials for neutron energies up to several hundred MeV are important for ADSS applications. Ramsauer model is well known and widely applied to understand systematics of neutron nucleus total cross sections. In this work, we examined the role of nuclear effective radius parameter (r$_0$) on Ramsauer model fits of neutron total cross sections. We performed Ramsauer model global analysis of the experimental neutron total cross section...

  10. Sampling the Hydrogen Atom

    Directory of Open Access Journals (Sweden)

    Graves N.

    2013-01-01

    Full Text Available A model is proposed for the hydrogen atom in which the electron is an objectively real particle orbiting at very near to light speed. The model is based on the postulate that certain velocity terms associated with orbiting bodies can be considered as being af- fected by relativity. This leads to a model for the atom in which the stable electron orbits are associated with orbital velocities where Gamma is n /α , leading to the idea that it is Gamma that is quantized and not angular momentum as in the Bohr and other models. The model provides a mechanism which leads to quantization of energy levels within the atom and also provides a simple mechanical explanation for the Fine Struc- ture Constant. The mechanism is closely associated with the Sampling theorem and the related phenomenon of aliasing developed in the mid-20th century by engineers at Bell labs.

  11. Multiphoton ionization of atoms

    International Nuclear Information System (INIS)

    This article provides an overview of the current understanding of multiphoton ionization of atoms. It begins with an introductory section to explain the background of the subject. Then the article develops the three topics which have been central themes of discussion in multiphoton ionization of atoms these past few years: multiply charged ion production, very high order harmonic generation, and above-threshold ionization, a name given to the absorption of a very large number of photons by an already ionized electron. A large part of the review is devoted to some theoretical aspects of multiphoton ionization of atoms and especially non-perturbative theories. Finally the article considers the very near future prospects of laser-electron interactions and more generally laser-matter interactions at 1018 -1019 W cm-2, an intensity range now within reach due to new short pulse laser technology. (author)

  12. Magnetic dipole excitations of the 163Dy nucleus

    Science.gov (United States)

    Zenginerler, Zemine; Tabar, Emre; Yakut, Hakan; Kuliev, Ali Akbar; Guliyev, Ekber

    2014-03-01

    In this study some properties of the magnetic dipole excitations of the deformed odd mass 163Dy nucleus were studied by using Quasiparticle-phonon nuclear model (QPNM). The several of the ground-state and low-lying magnetic dipole (M1) mode characteristics were calculated for deformed odd-mass nuclei using a separable Hamiltonian within the QPNM. The M1 excited states, reduced transition probabilities B(M1), the ground-state magnetic properties such as magnetic moment (μ), intrinsic magnetic moment (gK) , effective spin factor (gseff.) are the fundamental characteristics of the odd-mass nucleus and provide key information to understand nuclear structure. The theoretical results were compared with the available experimental data and other theoretical approaches. Calculations show that the spin-spin interaction in this isotopes leads to polarization effect influencing the magnetic moments. Furthermore we found a strong fragmentation of the M1 strength in 163Dy nucleus which was in qualitative agreement with the experimental data. Sakarya University, Project Number: 2012-50-02-007 and Z.Zenginerler acknowledge to TUBITAK-TURKEY 2013, fellowship No: 2219.

  13. Pictures of Particle Production in Proton-Nucleus Collisions

    CERN Document Server

    Mueller, Alfred H

    2016-01-01

    This work focuses on gluon(jet) production in dilute(proton)-dense(nucleus) collisions. Depending on the frame and gauge, gluon production can be viewed as a freeing of gluons coming from either the proton wave function or from the nucleus wave function. These (apparently) very different pictures must lead to the same result and the purpose of this paper is to see how that happens. The focus is on gluons having $k_\\perp\\sim Q_S$ or gluons in the scaling region $k_\\perp/Q_S\\gg 1$. In the McLerran-Venugopalan(MV) model with $k_\\perp\\sim Q_S$ we are able to derive gluon production in a way that (graphically) manifestly shows $k_\\perp$-factorization in terms of the number density of gluons in the nuclear wave function. We presume that this picture, and $k_\\perp$-factorization, continues to hold in the presence of small-$x$ evolution although we have not been able to explicitly verify this. Our result is in agreement with usual $k_\\perp$-factorization where the gluon number density of the nucleus does not appear i...

  14. Structure of Tz = 3 / 2 , 33P Nucleus

    Science.gov (United States)

    Lubna, Rebeka Sultana; Tripathi, Vandana; Tabor, Samuel; Tai, Pei-Laun; Bender, Peter

    2016-03-01

    The excited states of the nucleus 33P were populated by the 18O(18O, p-2n γ)33P fusion evaporation reaction at Elab = 25 MeV.Gammasphere was used along with the particle detector Microball to detect the γ emissions in coincidence with the emitted charged particles from the compound nucleus 36S. The auxiliary detector Microball was used to select the charged particle channel and to determine the exact position and the energy of the emitted proton. The purpose of finding the position and energy of proton was to determine a more precise angle between the recoil nucleus and the emitted γ which was later employed to get a better Doppler correction. Along with the selection of the proton channel, the γ- γ coincidence technique helped to isolate 33P from the other phosphorus isotopes and also reduced the contaminations from the dominant pure neutron channels. A number of transitions and states was identified that were not observed before. The 4 π arrangement of Gammasphere offered an excellent opportunity to measure the angular distribution of the electromagnetic emissions leading to the assignment of the spins for most of the new states. The experimental observations were compared to the shell model calculation using Work supported by the U.S. National Science Foundation under Grant No. 1401574.

  15. An Automatic Learning-Based Framework for Robust Nucleus Segmentation.

    Science.gov (United States)

    Xing, Fuyong; Xie, Yuanpu; Yang, Lin

    2016-02-01

    Computer-aided image analysis of histopathology specimens could potentially provide support for early detection and improved characterization of diseases such as brain tumor, pancreatic neuroendocrine tumor (NET), and breast cancer. Automated nucleus segmentation is a prerequisite for various quantitative analyses including automatic morphological feature computation. However, it remains to be a challenging problem due to the complex nature of histopathology images. In this paper, we propose a learning-based framework for robust and automatic nucleus segmentation with shape preservation. Given a nucleus image, it begins with a deep convolutional neural network (CNN) model to generate a probability map, on which an iterative region merging approach is performed for shape initializations. Next, a novel segmentation algorithm is exploited to separate individual nuclei combining a robust selection-based sparse shape model and a local repulsive deformable model. One of the significant benefits of the proposed framework is that it is applicable to different staining histopathology images. Due to the feature learning characteristic of the deep CNN and the high level shape prior modeling, the proposed method is general enough to perform well across multiple scenarios. We have tested the proposed algorithm on three large-scale pathology image datasets using a range of different tissue and stain preparations, and the comparative experiments with recent state of the arts demonstrate the superior performance of the proposed approach. PMID:26415167

  16. Examining the Structure of the Oxygen-16 Nucleus

    Science.gov (United States)

    Sauer, Ethan; Aprahamian, Ani; Tan, Wanpeng; Gyurjinyan, Armen; Frentz, Bryce; Guerin, Benjamin

    2015-10-01

    The intent of this work is to explore the structure of the nucleus of Oxygen-16 (16O), which consists of four alpha particles, each with two protons and two neutrons. 16O is generated via the fusion of helium and carbon during stellar nucleosynthesis. This reaction is crucial to the existence of life. By measuring the structure of the 16O nucleus, we hope to gain a better understanding of stellar evolution and processes. The theoretical state of most interest is a linear arrangement of the four alpha particles, proposed by Chevallier et al. in their 1967 paper to explain the surprisingly large moment of inertia of the nucleus they measured. The existence of this state can be most accurately observed through an analysis of the energy spectra of the decay products. This method has previously been implemented at Notre Dame by Freer et al. when a similar structure, that of Carbon-12 (12C), was analyzed, and a previously unknown state was observed. The data gathered is analyzed using the method of angular correlation, which makes use of the angles and energies of decay products relative to the center of mass frame to reconstruct possible spins of the initial state. Analysis is currently underway and results will be presented at CEU 2015. Supported by NSF Grant PHY-1419765.

  17. Compound nucleus formation in reactions between massive nuclei: Fusion barrier

    International Nuclear Information System (INIS)

    The evaporation residue cross sections σER in reactions between massive nuclei have been analyzed within different models of complete fusion. The calculations in the framework of the optical model, the surface friction model, and the macroscopic dynamic model can give the results which are by few orders of magnitude different from experimental data. This takes place due to neglect of the competition between complete fusion and quasifission. A possible mechanism of compound nucleus formation in heavy-ion-induced reactions has been suggested. The analysis of the complete fusion of nuclei on the basis of dinuclear system approach has allowed one to reveal an important feature of the fusion process of massive nuclei, that is, the appearance of the fusion barrier during dinuclear system evolution to a compound nucleus. As a result, the competition between complete fusion and quasifission arises and strongly reduces the cross section of the compound nucleus formation. A model is proposed for calculation of this competition in a massive symmetric dinuclear system. This model is applied for collision energies above the Coulomb barrier. The σER values calculated in the framework of dinuclear system approach seem to be close to the experimental data. For illustration the reactions 100Mo+100Mo, 110Pd+110Pd, and 124Sn+96Zr have been considered

  18. Incorporation of mammalian actin into microfilaments in plant cell nucleus

    Directory of Open Access Journals (Sweden)

    Paves Heiti

    2004-04-01

    Full Text Available Abstract Background Actin is an ancient molecule that shows more than 90% amino acid homology between mammalian and plant actins. The regions of the actin molecule that are involved in F-actin assembly are largely conserved, and it is likely that mammalian actin is able to incorporate into microfilaments in plant cells but there is no experimental evidence until now. Results Visualization of microfilaments in onion bulb scale epidermis cells by different techniques revealed that rhodamine-phalloidin stained F-actin besides cytoplasm also in the nuclei whereas GFP-mouse talin hybrid protein did not enter the nuclei. Microinjection of fluorescently labeled actin was applied to study the presence of nuclear microfilaments in plant cells. Ratio imaging of injected fluorescent rabbit skeletal muscle actin and phalloidin staining of the microinjected cells showed that mammalian actin was able to incorporate into plant F-actin. The incorporation occurred preferentially in the nucleus and in the perinuclear region of plant cells whereas part of plant microfilaments, mostly in the periphery of cytoplasm, did not incorporate mammalian actin. Conclusions Microinjected mammalian actin is able to enter plant cell's nucleus, whereas incorporation of mammalian actin into plant F-actin occurs preferentially in the nucleus and perinuclear area.

  19. N body simulations of the nucleus of M 31

    CERN Document Server

    Emsellem, E; Emsellem, Eric; Combes, Francoise

    1997-01-01

    We test through stellar N-body simulations some scenarios to explain the dynamics of the peculiar nucleus of the Andromeda galaxy (M~31): although HST observations reveal a double nucleus morphology, the rotation field is almost symmetric around the bulge gravity centre and the velocity dispersion is off-centred. We show that any m=1 perturbation has a very short life-time (a few 10$^5$ yr). Assuming that the bright peak (P1) is a cold stellar cluster infalling into the nucleus, and that the large central velocity gradient is due to a central dark mass (in the range 7~$10^7$--$10^8$~\\Msun), we obtain a reasonably good fit to the observations. However, if this cluster lies in the central 20 pc, we estimate the life-time of the cluster to be less than 0.5~Myr. The dynamical friction is more efficient than estimated by analytic formulae, and is essentially due to the deformation of the stellar cluster through the huge tidal forces provided by the black hole. We show that the cluster cannot be on a circular orbit...

  20. Atoms in Slovakia

    International Nuclear Information System (INIS)

    In this book the history of development of using of nuclear energy in the Slovak Republic as well as in the Czechoslovakia (before 1993 year) is presented. The aim of the book is to preserve the memory of the period when the creation and development of nuclear physics, technology, nuclear medicine, radioecology and energetics in Slovakia occurred - as witnessed by people who experienced this period and to adapt it to future generations. The Editorial board of the SNUS collected the views of 60 contributors and distinguished workers - Slovakian experts in nuclear science, education and technology. Calling upon a wide spectrum of experts ensured an objective historical description of the period. A huge amount of subjective views on recent decades were collected and supported by a wealth of photographic documentation. This created a synthesised reflection on the history of the 'atoms' in Slovakia. The book contains 15 tables, 192 black and white and 119 colour pictures from around the world and from places involved in the compilation of the study and with the study of atomic science in Slovakia. The main chapters are as follows: Atoms in the world, Atoms in Slovakia, Atoms in the educational system, Atoms in health services (Radiology, Nuclear medicine, Radiation protection, the Cyclotron centre of the Slovak Republic), Radioecology, Other applications of irradiation, Nuclear energetics (Electric energy in the second half of the 20th century, NPP Bohunice, NPP Mochovce, the back-end of Nuclear energetics, Big names in Nuclear energetics in Slovakia), Chronology and an Appendix entitled 'Slovak companies in nuclear energetics'

  1. Azimuthal distributions of final-state particles and fragments and transverse structure of emission source in high-energy nucleus-nucleus collisions

    Institute of Scientific and Technical Information of China (English)

    Liu Fu-Hu; Ma Yin-Qun; Duan Mai-Ying

    2005-01-01

    The azimuthal distributions of final-state particles and fragments produced in high-energy nucleus-nucleus collisions are described by a modified multisource ideal gas model which contains the expansions and movements of the emission sources. The transverse structures of the sources are given in the transverse plane by momentum components px and py, and described by parameters in the model. The results of the azimuthal distributions, calculated by the Monte Carlo method, are in good agreement with the experimental data in nucleus-nucleus collisions at high energies.

  2. Comparison of J/ψ-suppression in photon, hadron and nucleus-nucleus collisions: Where is the quark-gluon plasma?

    International Nuclear Information System (INIS)

    The data of J/ψ-production cross sections from photon, hadron and nucleus-nucleus collisions are plotted against the length of the canti c final state trajectory in nuclear matter. A value for the absorption cross section per nucleon of σabsψN=(6.2±0.3) mb is deduced from the baryon and photon induced reactions and σabsψN=(6.9±1.0) mb from the nucleus-nucleus collisions. The equality of cross sections implies that additional suppression effects from a quark-gluon plasma are not visible. (orig.)

  3. Polarized atomic hydrogen beam

    Energy Technology Data Exchange (ETDEWEB)

    Chan, N.; Crowe, D.M.; Lubell, M.S.; Tang, F.C.; Vasilakis, A.; Mulligan, F.J.; Slevin, J.

    1988-12-01

    We describe the design and operating characteristics of a simple polarized atomic hydrogen beam particularly suitable for applications to crossed beams experiments. In addition to experimental measurements, we present the results of detailed computer models, using Monte-Carlo ray tracing techniques, optical analogs, and phase-space methods, that not only provide us with a confirmation of our measurement, but also allow us to characterize the density, polarization, and atomic fraction of the beam at all points along its path. As a subsidiary result, we also present measurements of the relative and absolute efficiencies of the V/G Supavac mass analyzer for masses 1 and 2.

  4. D^- mesic atoms

    OpenAIRE

    García Recio, Carmen; Nieves Pamplona, Juan Miguel; Salcedo, Lorenzo Luis; Tolós Rigueiro, Laura

    2011-01-01

    The anti-D meson self-energy is evaluated self-consistently, using unitarized coupled-channel theory, by computing the in-medium meson-baryon T-matrix in the C=-1,S=0 sector. The heavy pseudo-scalar and heavy vector mesons, anti-D and anti-D^*, are treated on equal footing as required by heavy quark spin symmetry. Results for energy levels and widths of D^- mesic atoms in 12C, 40Ca, 118Sn and 208Pb are presented. The spectrum contains states of atomic and of nuclear types for all nuclei. anti...

  5. Atomic Force Microscope

    Energy Technology Data Exchange (ETDEWEB)

    Day, R.D.; Russell, P.E.

    1988-12-01

    The Atomic Force Microscope (AFM) is a recently developed instrument that has achieved atomic resolution imaging of both conducting and non- conducting surfaces. Because the AFM is in the early stages of development, and because of the difficulty of building the instrument, it is currently in use in fewer than ten laboratories worldwide. It promises to be a valuable tool for obtaining information about engineering surfaces and aiding the .study of precision fabrication processes. This paper gives an overview of AFM technology and presents plans to build an instrument designed to look at engineering surfaces.

  6. Korean atomic bomb victims.

    Science.gov (United States)

    Sasamoto, Yukuo

    2009-01-01

    After colonizing Korea, Japan invaded China, and subsequently initiated the Pacific War against the United States, Britain, and their allies. Towards the end of the war, U.S. warplanes dropped atomic bombs on Hiroshima and Nagasaki, which resulted in a large number of Koreans who lived in Hiroshima and Nagasaki suffering from the effects of the bombs. The objective of this paper is to examine the history of Korea atomic bomb victims who were caught in between the U.S., Japan, the Republic of Korea (South Korea) and the Democratic People's Republic of Korea (North Korea). PMID:20521424

  7. Optically pumped atoms

    CERN Document Server

    Happer, William; Walker, Thad

    2010-01-01

    Covering the most important knowledge on optical pumping of atoms, this ready reference is backed by numerous examples of modelling computation for optical pumped systems. The authors show for the first time that modern scientific computing software makes it practical to analyze the full, multilevel system of optically pumped atoms. To make the discussion less abstract, the authors have illustrated key points with sections of MATLAB codes. To make most effective use of contemporary mathematical software, it is especially useful to analyze optical pumping situations in the Liouville spa

  8. Hirshfeld atom refinement

    Directory of Open Access Journals (Sweden)

    Silvia C. Capelli

    2014-09-01

    Full Text Available Hirshfeld atom refinement (HAR is a method which determines structural parameters from single-crystal X-ray diffraction data by using an aspherical atom partitioning of tailor-made ab initio quantum mechanical molecular electron densities without any further approximation. Here the original HAR method is extended by implementing an iterative procedure of successive cycles of electron density calculations, Hirshfeld atom scattering factor calculations and structural least-squares refinements, repeated until convergence. The importance of this iterative procedure is illustrated via the example of crystalline ammonia. The new HAR method is then applied to X-ray diffraction data of the dipeptide Gly–l-Ala measured at 12, 50, 100, 150, 220 and 295 K, using Hartree–Fock and BLYP density functional theory electron densities and three different basis sets. All positions and anisotropic displacement parameters (ADPs are freely refined without constraints or restraints – even those for hydrogen atoms. The results are systematically compared with those from neutron diffraction experiments at the temperatures 12, 50, 150 and 295 K. Although non-hydrogen-atom ADPs differ by up to three combined standard uncertainties (csu's, all other structural parameters agree within less than 2 csu's. Using our best calculations (BLYP/cc-pVTZ, recommended for organic molecules, the accuracy of determining bond lengths involving hydrogen atoms from HAR is better than 0.009 Å for temperatures of 150 K or below; for hydrogen-atom ADPs it is better than 0.006 Å2 as judged from the mean absolute X-ray minus neutron differences. These results are among the best ever obtained. Remarkably, the precision of determining bond lengths and ADPs for the hydrogen atoms from the HAR procedure is comparable with that from the neutron measurements – an outcome which is obtained with a routinely achievable resolution of the X-ray data of 0.65 Å.

  9. Polarized atomic beams for targets

    International Nuclear Information System (INIS)

    The basic principle of the production of polarized atomic hydrogen and deuterium beams are reviewed. The status of the present available polarization, density and intensity are presented. The improvement of atomic beam density by cooling the hydrogen atoms to low velocity is discussed. The possible use of polarized atomic beams as targets in storage rings is shown. It is proposed that polarized atomic beams can be used to produce polarized gas targets with high polarization and greatly improved density

  10. Search for a permanent EDM with laser cooled radioactive atom

    Science.gov (United States)

    Sakemi, Yasuhiro

    2014-09-01

    To explore the mechanism for the generation of the matter-antimatter asymmetry in the universe, the study on fundamental symmetry violation using the trapped radioactive atoms with laser cooling techniques is being promoted. An Electric Dipole Moment (EDM) of the elementary particle is a good prove to observe the phenomena beyond the Standard Model. A finite value of EDM means the violation of the time reversal symmetry, and the CP violation under the CPT invariance. In paramagnetic atoms, an electron EDM results in an atomic EDM enhanced by the factor of the 3rd power of the charge of the nucleus due the relativistic effects. A heaviest alkali element francium (Fr), which is the radioactive atom, has the largest enhancement factor K ~ 895 in atomic system. Then, we are developing a high intensity laser cooled Fr factory at Cyclotron and Radioisotope Center (CYRIC), Tohoku University to search for the EDM of Fr with the accuracy of 10-29 e cm. To overcome the current accuracy limit of the EDM, it is necessary to realize the high intensity Fr source and to reduce the systematic error due to the motional magnetic field and inhomogeneous applied field. To reduce the dominant component of the systematic errors mentioned above, we will confine the Fr atoms in the small region with the Magneto-Optical Trap (MOT) and optical lattice using the laser cooling and trapping techniques. The construction of the experimental apparatus is making progress, and the new thermal ionizer already produces the Fr of ~ 10 6 ions/s with the primary beam intensity 200 nA. The extracted Fr ion beam is transported to the neutralizer, which is located 10 m downstream, and the produced neutral Fr atoms are introduced into the MOT to load the next trapping system such as the optical dipole force trap and optical lattice. The coherence time will be increased in the laser trapping system, and the present status of the experiment will be reported.

  11. Production of Kaon and $\\Lambda$ in nucleus-nucleus collisions at ultra-relativistic energy from a blast wave model

    CERN Document Server

    Zhang, Song; Chen, Jin-Hui; Zhong, Chen

    2014-01-01

    The particle production of Kaon and $\\Lambda$ are studied in nucleus-nucleus collisions at relativistic energy based on a chemical equilibrium blast-wave model. The transverse momentum spectra of Kaon and $\\Lambda$ at the kinetic freeze-out stage from our model are in good agreement with the experimental results. The kinetic freeze-out parameters of temperature ($T_{kin}$) and radial flow parameter $\\rho_{0}$ are presented for the FOPI, RHIC and LHC energies. And the resonance decay effect is also discussed. The systematic study for beam energy dependence of the strangeness particle production will help us to better understand the properties of the matter created in heavy-ion collisions at the kinetic freeze-out stage.

  12. Hadron multiplicities and chemical freeze-out conditions in proton-proton and nucleus-nucleus collisions

    Science.gov (United States)

    Vovchenko, V.; Begun, V. V.; Gorenstein, M. I.

    2016-06-01

    New results of the NA61/SHINE Collaboration at the CERN SPS on mean hadron multiplicities in proton-proton (p+p) interactions are analyzed within the transport models and the hadron resonance gas (HRG) statistical model. The chemical freeze-out parameters in p+p interactions and central Pb+Pb (or Au+Au) collisions are found and compared with each other in the range of the center-of-mass energy of the nucleon pair √{sN N}=3.2 -17.3 GeV. The canonical ensemble formulation of the HRG model is used to describe mean hadron multiplicities in p+p interactions and the grand canonical ensemble in central Pb+Pb and Au+Au collisions. The chemical freeze-out temperatures in p+p interactions are found to be larger than the corresponding temperatures in central nucleus-nucleus collisions.

  13. Charged pion coherent production in nucleus-nucleus collisions at incident energies between 86 and 330 MeV/nucleon

    International Nuclear Information System (INIS)

    We have studied pion production in nucleus-nucleus collisions at foward angles for about twenty projectile target combinations. The incident energies were below or around 300 MeV/nucleon which is the threshold of the elementary reaction NN → NNπ. The study of the inclusive spectra shows some new ideas: shell effects in pion production, collective resonances excitations. These spectra have been analyzed following different models: hard-scattering models which describe the interaction on the basis of the elementary reaction NN → NNπ, statistical model and the pionic cloud model which is a coherent description of the interaction. In the study of the exclusive reactions, we established some empiric rules concerning the cross-section variations. These exclusive spectra were then analyzed in the framework of two-models: the semi-phenomenological model and the pionic fusion

  14. Experimental atomic physics

    International Nuclear Information System (INIS)

    The atomic structure and collision phenomena of highly stripped ions in the range Z = 6 to 35 were studied. Charge-transfer and multiple-electron-loss cross sections were determined. Absolute x-ray-production cross sections for incident heavy ions were measured. 10 figures, 1 table

  15. Conformal atoms in Supergravity

    Science.gov (United States)

    Jankowski, Jakub

    2016-01-01

    In this note, we summarize recent attempts to construct holographic models of atoms and lattices in the context of applications to solid state physics. The simplest setup turned out to impose strong constraints on the choice of matter interactions of dual gravitational theory.

  16. Atomic physics and reality

    CERN Multimedia

    1985-01-01

    An account of the long standing debate between Niels Bohr and Albert Einstein regarding the validity of the quantum mechanical description of atomic phenomena.With physicts, John Wheeler (Texas), John Bell (CERN), David Rohm (London), Abner Shimony (Boston), Alain Aspect (Paris)

  17. Spectra of alkali atoms

    International Nuclear Information System (INIS)

    Emission spectra of alkali atoms has been determined by using spectrometer at the ultraviolet to infra red waves range. The spectra emission can be obtained by absorption spectrophotometric analysis. Comparative evaluations between experimental data and data handbook obtained by spark method were also presented. (author tr.)

  18. Ludwig Boltzmann: Atomic genius

    International Nuclear Information System (INIS)

    On the centenary of the death of Ludwig Boltzmann, Carlo Cercignani examines the immense contributions of the man who pioneered our understanding of the atomic nature of matter. The man who first gave a convincing explanation of the irreversibility of the macroscopic world and the symmetry of the laws of physics was the Austrian physicist Ludwig Boltzmann, who tragically committed suicide 100 years ago this month. One of the key figures in the development of the atomic theory of matter, Boltzmann's fame will be forever linked to two fundamental contributions to science. The first was his interpretation of 'entropy' as a mathematically well-defined measure of the disorder of atoms. The second was his derivation of what is now known as the Boltzmann equation, which describes the statistical properties of a gas as made up of molecules. The equation, which described for the first time how a probability can evolve with time, allowed Boltzmann to explain why macroscopic phenomena are irreversible. The key point is that while microscopic objects like atoms can behave reversibly, we never see broken coffee cups reforming because it would involve a long series of highly improbable interactions - and not because it is forbidden by the laws of physics. (U.K.)

  19. Chiral atomically thin films

    Science.gov (United States)

    Kim, Cheol-Joo; Sánchez-Castillo, A.; Ziegler, Zack; Ogawa, Yui; Noguez, Cecilia; Park, Jiwoong

    2016-06-01

    Chiral materials possess left- and right-handed counterparts linked by mirror symmetry. These materials are useful for advanced applications in polarization optics, stereochemistry and spintronics. In particular, the realization of spatially uniform chiral films with atomic-scale control of their handedness could provide a powerful means for developing nanodevices with novel chiral properties. However, previous approaches based on natural or grown films, or arrays of fabricated building blocks, could not offer a direct means to program intrinsic chiral properties of the film on the atomic scale. Here, we report a chiral stacking approach, where two-dimensional materials are positioned layer-by-layer with precise control of the interlayer rotation (θ) and polarity, resulting in tunable chiral properties of the final stack. Using this method, we produce left- and right-handed bilayer graphene, that is, a two-atom-thick chiral film. The film displays one of the highest intrinsic ellipticity values (6.5 deg μm-1) ever reported, and a remarkably strong circular dichroism (CD) with the peak energy and sign tuned by θ and polarity. We show that these chiral properties originate from the large in-plane magnetic moment associated with the interlayer optical transition. Furthermore, we show that we can program the chiral properties of atomically thin films layer-by-layer by producing three-layer graphene films with structurally controlled CD spectra.

  20. Bonds Between Atoms.

    Science.gov (United States)

    Holden, Alan

    The field of inquiry into how atoms are bonded together to form molecules and solids crosses the borderlines between physics and chemistry encompassing methods characteristic of both sciences. At one extreme, the inquiry is pursued with care and rigor into the simplest cases; at the other extreme, suggestions derived from the more careful inquiry…

  1. Transition probabilities for atoms

    International Nuclear Information System (INIS)

    Current status of advanced theoretical methods for transition probabilities for atoms and ions is discussed. An experiment on the f values of the resonance transitions of the Kr and Xe isoelectronic sequences is suggested as a test for the theoretical methods

  2. Rydberg atom in gravity

    Energy Technology Data Exchange (ETDEWEB)

    Agrawal, Aniket [Indian Institute of Technology Delhi, New Delhi (India)

    2012-07-01

    Recently, Chiao predicted the quantum incompressibility of a falling Rydberg atom. A Hydrogen-like atom was considered in a very high n,l=m=n-1 state to calculate the effects of tidal gravitational forces on these states. The high values of quantum numbers ensure that gravitational effect is measurable on the *stretch* state. We consider a similar atom and derive the energy of a particular level under the influence of Newtonian gravity. A change in the frequency of observed transition is predicted for a freely falling Hydrogen atom. This change is calculated both in Newtonian gravity and in curved space. We see that the change in energy of the electron under gravity also depends on its principal quantum number. Thus there will be a shift in the frequency of the photon emitted by an electron making an ordinary transition from the state n=100, l=99, m=99 to the state n=99, l=98, m=98. Though this shift is quite less to be observed on Earth, it is measurable in satellites in a highly elliptical orbit about the earth, by spectroscopic methods. A similar result was derived by Chiao recently using a different argument. We conclude that the effect described by Chiao will be masked to a very large extent by the effect calculated above. Such perturbations might be important in emission spectra of white dwarfs and neutron stars.

  3. Effect of nuclear motion on the critical nuclear charge for two-electron atoms

    OpenAIRE

    King, Andrew W; Rhodes, Luke C; Readman, Charles A; Cox, Hazel

    2015-01-01

    A variational method for calculating the critical nuclear charge, Zc, required for the binding of a nucleus to two electrons is reported. The method is very effective and performs well compared to the traditional variational principle for calculating energy. The critical nuclear charge, which corresponds to the minimum charge required for the atomic system to have at least one bound state, has been calculated for helium-like systems both with infinite and finite nuclear masses. The value of $...

  4. Ionization cross sections of state selective atomic hydrogen by impact of multiply charged ions

    International Nuclear Information System (INIS)

    Ionization cross sections of atomic hydrogen in ground state and in metastable 2s state in collision with bare projectiles over a wide energy range have been calculated. The final state wave function considers the distortion due to Coulomb fields of both the projectile and the target nucleus. The present calculated total ionization cross-section values show good accord with the measurements for He2+, Li3- and C6+ impact at intermediate and high energy region. (author)

  5. The effect of the nuclear Coulomb field on atomic ionization at positron-electron annihilation in β+- decay

    Directory of Open Access Journals (Sweden)

    Fedotkin Sergey

    2015-01-01

    Full Text Available We consider the process of the annihilation of a positron emitted at β+- decay and a K-electron of the daughter atom. A part of energy during this process is passed to another K- electron and it leaves the atom. The influence of the Coulomb field on the positron and the ejected electron is considered. It was calculated the probability of this process for an atom with arbitrary Z is calculated. For the nucleus Ti the effect of the Coulomb field essentially increases the probability of the considered process.

  6. Coupled-Channel Investigation of the Collision of Protons and Antiprotons with Hydrogen- Like Atoms in the 2s States

    Institute of Scientific and Technical Information of China (English)

    Reda S. Tantawi

    2003-01-01

    The influence of the electric charge of both the projectile and the target nucleus on the cross section of the inelastic collision of protons and antiprotons with atoms is investigated at energies ranging from i to 2500 KeV. The impact parameter method is used to analyse the cross sections of the excitation of the n = 3 states of H atom and He+, Li2+ ions being initially in the excited 2s states. The calculated cross sections for hydrogen atoms are compared with the other theoretical results based on coupled-channels methods.

  7. Role of Nuclear Coulomb Attraction in Nonsequential Double Ionization of Argon Atom

    Institute of Scientific and Technical Information of China (English)

    汤清彬; 张东玲; 李盈傧; 余本海

    2011-01-01

    The microscopic recollision dynamics in strong-field nonsequential double ionization of Ar atoms is in- vestigated using three-dimensional classical ensembles. By adjusting the nuclear Coulomb potential, we can excellently reproduce the experimental results both within the laser intensity regimes well above the reeollision threshold and well below the recollision threshold quantitatively. More importantly, our trajectory analysis clearly reveals the particular electronic dynamics in recollision process: the momentum of the recolliding electron encounters a sudden change both in magnitude and in direction when it approaches the nucleus closely, which show that the nuclear Coulomb attraction plays a key role in the recollision process of nonsequential double ionization of Ar atoms.

  8. The ionized electron return phenomenon of Rydberg atom in crossed-fields

    Science.gov (United States)

    Dong, Chengwei; Wang, Peijie; Du, Mengli; Uzer, Turgay; Lan, Yueheng

    2016-05-01

    Rydberg atom is highly excited with one valence electron being in a high quantum state, which is very far away from the nucleus. The energy level is similar to that of the hydrogen atom. Introducing externally perpendicular electric and magnetic fields breaks the rotation symmetry and the traditional view is that the ionized electron crosses from the bound into the unbound region and will never return. However, we find that when the field is strong enough, the electron does not move off to infinity and there is a certain possibility of return. Three new periodic orbits are found by the variational method and the physical significance of the phenomenon is also discussed.

  9. Hadronic atoms and leptonic conservations: technical progress report, February 1, 1987-January 31, 1988

    International Nuclear Information System (INIS)

    The 1986 efforts on leptonic conservations have been on experiments at TRIUMF and LAMPF involving searches for a lepton flavor-violating reaction. The efforts on hadronic atoms (atoms formed with pions, kaons, and sigma-minus particles) have been on the completion of analyses from the experiments at TRIUMF, LAMPF, and BNL. The experiment on leptonic conservations at TRIUMF is MUBAR, an attempt to measure the rate of the muonium to antimuonium conversion process (μ+e- → μ-e+). The reaction would violate additive lepton flavor conservation. Details of this experiment are contained in this paper. Concerning hadronic atoms at LAMPF, the analysis on pionic atoms from Fe, Co, and Ni isotopes has been completed. The energies and the widths of the 3d-2p x-ray transitions which were the last observed transitions before the pion was captured by the nucleus have been measured

  10. Search for Electric dipole moment (EDM) in laser cooled and trapped 225Ra atoms

    Science.gov (United States)

    Kalita, Mukut; Bailey, Kevin; Dietrich, Matthew; Green, John; Holt, Roy; Korsch, Wolfgang; Lu, Zheng-Tian; Lemke, Nathan; Mueller, Peter; O'Connor, Tom; Parker, Richard; Singh, Jaideep; Trimble, Will; Argonne National Laboratory Collaboration; University Of Chicago Collabration; University Of Kentucky Collaboration

    2014-05-01

    We are searching for an EDM of the diamagnetic 225Ra atom. 225Ra has nuclear spin I =1/2. Experimental sensitivity to its EDM is enhanced due to its heavy mass and the increased Schiff moment of its octupole deformed nucleus. Our experiment involves collecting laser cooled Ra atoms in a magneto-optical trap (MOT), transporting them 1 meter with a far off-resonant optical dipole trap (ODT) and then transferring the atoms to a second standing-wave ODT in our experimental chamber. We will report our recent experiences in polarizing and observing Larmor precession of 225Ra atoms in parallel electric and magnetic fields in a magnetically shielded region and progress towards a first measurement of the EDM of 225Ra. This work is supported by DOE, Office of Nuclear Physics, under contract No. DE-AC02-06CH11357 and contract No. DE-FG02-99ER41101.

  11. Rydberg atom ionization by slow collisions with alkali element atoms

    International Nuclear Information System (INIS)

    A new mechanism for ionization of highexcited atoms due to the electron capture into the autoionization state of a negative ion is suggested. Calculations of cross-sections and the ionization rate for sodium and lithium atoms collisions are performed

  12. Versatile compact atomic source for high resolution dual atom interferometry

    CERN Document Server

    Müller, T; Gilowski, M; Jentsch, C; Rasel, E M; Ertmer, W

    2007-01-01

    We present a compact $^{87}$Rb atomic source for high precision dual atom interferometers. The source is based on a double-stage magneto-optical trap (MOT) design, consisting of a 2-dimensional (2D)-MOT for efficient loading of a 3D-MOT. The accumulated atoms are precisely launched in a horizontal moving molasses. Our setup generates a high atomic flux ($>10^{10}$ atoms/s) with precise and flexibly tunable atomic trajectories as required for high resolution Sagnac atom interferometry. We characterize the performance of the source with respect to the relevant parameters of the launched atoms, i.e. temperature, absolute velocity and pointing, by utilizing time-of-flight techniques and velocity selective Raman transitions.

  13. Atom inlays performed at room temperature using atomic force microscopy

    Science.gov (United States)

    Sugimoto, Yoshiaki; Abe, Masayuki; Hirayama, Shinji; Oyabu, Noriaki; Custance, Óscar; Morita, Seizo

    2005-02-01

    The ability to manipulate single atoms and molecules laterally for creating artificial structures on surfaces is driving us closer to the ultimate limit of two-dimensional nanoengineering. However, experiments involving this level of manipulation have been performed only at cryogenic temperatures. Scanning tunnelling microscopy has proved, so far, to be a unique tool with all the necessary capabilities for laterally pushing, pulling or sliding single atoms and molecules, and arranging them on a surface at will. Here we demonstrate, for the first time, that it is possible to perform well-controlled lateral manipulations of single atoms using near-contact atomic force microscopy even at room temperature. We report the creation of 'atom inlays', that is, artificial atomic patterns formed from a few embedded atoms in the plane of a surface. At room temperature, such atomic structures remain stable on the surface for relatively long periods of time.

  14. The role of the nucleus basalis of Meynert and reticular thalamic nucleus in pathogenesis of genetically determined absence epilepsy in rats : A lesion study

    NARCIS (Netherlands)

    Berdiev, R. K.; Chepurnov, S. A.; Veening, J. G.; Chepurnova, N. E.; van Luiftelaar, G.

    2007-01-01

    The role of cholinergic nucleus basalis (of Meynert) and the reticular thalamic nucleus in mechanisms of the generation spontaneous spike-and-wave discharges (SWDs) was investigated in the WAG/Rij rat model of absence epilepsy. Selective lesions were affected by local unilateral intraparenchymal inf

  15. Atomic Spectroscopy and Collisions Using Slow Antiprotons \\\\ ASACUSA Collaboration

    CERN Multimedia

    Matsuda, Y; Lodi-rizzini, E; Kuroda, N; Schettino, G; Hori, M; Pirkl, W; Mascagna, V; Malbrunot, C L S; Yamazaki, Y; Eades, J; Simon, M; Massiczek, O; Sauerzopf, C; Breuker, H; Nagata, Y; Uggerhoj, U I; Mc cullough, R W; Toekesi, K M; Venturelli, L; Widmann, E; Zmeskal, J; Kanai, Y; Hayano, R; Knudsen, H; Kristiansen, H; Todoroki, K; Bartel, M A; Moller, S P; Charlton, M; Leali, M; Diermaier, M; Kolbinger, B

    2002-01-01

    ASACUSA (\\underline{A}tomic \\underline{S}pectroscopy \\underline{A}nd \\underline{C}ollisions \\underline{U}sing \\underline{S}low \\underline{A}ntiprotons) is a collaboration between a number of Japanese and European research institutions, with the goal of studying bound and continuum states of antiprotons with simple atoms.\\\\ Three phases of experimentation are planned for ASACUSA. In the first phase, we use the direct $\\overline{p}$ beam from AD at 5.3 MeV and concentrate on the laser and microwave spectroscopy of the metastable antiprotonic helium atom, $\\overline{p}$He$^+$, consisting of an electron and antiproton bound by the Coulomb force to the helium nucleus. Samples of these are readily created by bringing AD antiproton beam bunches to rest in helium gas. With the help of techniques developed at LEAR for resonating high precision laser beams with antiproton transitions in these atoms, ASACUSA achieved several of these first-phase objectives during a few short months of AD operation in 2000. Six atomic tr...

  16. Is Einstein the Father of the Atomic Bomb

    Science.gov (United States)

    Lustig, Harry

    2009-05-01

    Soon after the American atomic bombs were dropped on Hiroshima and Nagasaki, the notion took hold in the popular mind that Albert Einstein was ``the father of the bomb.'' The claim of paternity rests on the belief that E=mc2 is what makes the release of enormous amounts of energy in the fission process possible and that the atomic bomb could not have been built without it. This is a misapprehension. Most physicists have known that all along. Nevertheless in his reaction to the opera Dr. Atomic, a prominent physicist claimed that Einstein's discovery that matter can be transformed into energy ``is precisely what made the bomb possible.'' In fact what makes the fission reaction and one of its applications,the atomic bomb, possible is the smaller binding energies of fission products compared to the binding energies of the nuclei that undergo fission.The binding energies of nuclei are a well understood consequence of the numbers and arrangements of protons and neutrons in the nucleus and of quantum-mechanical effects. The realization that composite systems have binding energies predates relativity. In the 19th century they were ascribed to potential and other forms of energy that reside in the system. With Einstein they became rest mass energy. While E=mc2 is not the cause of fission, measuring the masses of the participants in the reaction does permit an easy calculation of the kinetic energy that is released.

  17. Synthesis and Pharmacological Evaluation of α4β2 Nicotinic Ligands with a 3-Fluoropyrrolidine Nucleus.

    Science.gov (United States)

    Tamborini, Lucia; Pinto, Andrea; Ettari, Roberta; Gotti, Cecilia; Fasoli, Francesca; Conti, Paola; De Micheli, Carlo

    2015-06-01

    Nicotinic acetylcholine receptors (nAChRs) play an important role in many central nervous system disorders such as Alzheimer's and Parkinson's diseases, schizophrenia, and mood disorders. The α(4)β(2) subtype has emerged as an important target for the early diagnosis and amelioration of Alzheimer's disease symptoms. Herein we report a new class of α(4)β(2) receptor ligands characterized by a basic pyrrolidine nucleus, the basicity of which was properly decreased through the insertion of a fluorine atom at the 3-position, and a pyridine ring carrying at the 3-position substituents known to positively affect affinity and selectivity toward the α(4)β(2) subtype. Derivatives 3-(((2S,4R)-4-fluoropyrrolidin-2-yl)methoxy)-5-(phenylethynyl)pyridine (11) and 3-((4-fluorophenyl)ethynyl)-5-(((2S,4R)-4-fluoropyrrolidin-2-yl)methoxy)pyridine (12) were found to be the most promising ligands identified in this study, showing good affinity and selectivity for the α(4)β(2) subtype and physicochemical properties predictive of a relevant central nervous system penetration. PMID:25882435

  18. Hyperfine field on Fe, Rh, Cd and Sn nucleus probes in chromium host

    Directory of Open Access Journals (Sweden)

    S. Sirousi

    2005-03-01

    Full Text Available   The incommensurate spin -density –wave magnetism of Cr has attracted great interest since its discovery via neutron scattering. Although the existence of spin- density –wave has been confirmed by experiment but the calculations which have been carried out have not been able to predict the correct ground state magnetic phase for chromium yet. To predict the magnetic hyperfine field at nucleus of different impurities in Cr host, we calculated the hyperfine field on Cd, Sn, Rh and Fe probes in the first step. Our calculations were performed within the framework of density functional theory, using the full-potential-linearized augmented plane-wave method. We used a supercell constructed from 8 bcc unit cells with impurity concentratin of 6.25 % and to analysise the supercell size effect on different magnetic quantities we repeated our calculation using a supercell with 54 atoms. The result of this effort showed that the magnetic hyperfine field and magnetic moment of nearesrt Cr is very little influenced by the size of supercell, so we can calculate the magnetic hyperfine field if it’s quantity is known in different alloys. we showed that the local properties such as hyperfine field, are calculated with acceptable accuracy by using small supercells. Meanwhile, we studied the structural and magnetic properties of different alloys and showed that the Fe alloy has two defferent magnetic phase.

  19. Low-lying dipole strength in the N = 28 shell-closure nucleus {sup 52}Cr

    Energy Technology Data Exchange (ETDEWEB)

    Pai, Haridas; Beller, Jacob; Benouaret, Nadia; Enders, Joachim; Hartmann, Timo; Karg, Oliver; Neumann-Cosel, Peter von; Pietralla, Norbert; Ponomarev, Vladimir Yu.; Romig, Christopher; Schnorrenberger, Linda; Volz, Stephan; Zweidinger, Markus [Institut fuer Kernphysik, Technische Universitaet Darmstadt (Germany); Scheck, Marcus [Institut fuer Kernphysik, Technische Universitaet Darmstadt (Germany); School of Engineering, University of the West of Scotland, Paisley (United Kingdom); SUPA, Scottish Universities Physics Alliance, Glasgow (United Kingdom)

    2014-07-01

    Low-lying electric and magnetic dipole strengths (E1 and M1, respectively) of atomic nuclei have drawn considerable attention in the last decade. The low-lying dipole strength of the N = 28 closed-shell nucleus {sup 52}Cr was studied with nuclear resonance fluorescence up to 9.9 MeV, using bremsstrahlung at the superconducting Darmstadt electron linear accelerator S-DALINAC. Twenty-eight spin-1 states were observed between 5.0 and 9.5 MeV excitation energy, 14 of those for the first time and uncertainties for cross sections were reduced in many cases. Both, electric dipole excitations (E1, around 8 MeV) and magnetic dipole excitations (M1, around 9 MeV) were detected. Microscopic calculations within the quasiparticle-phonon nuclear model were performed using a basis which includes one-, two-, and three-phonon configurations to interpret the dipole strength distributions of {sup 52}Cr and show good agreement with experimental results.

  20. Microtraps and Atom Chips: Toolboxes for Cold Atom Physics

    OpenAIRE

    Feenstra, L.; Andersson, L. M.; Schmiedmayer, J.

    2003-01-01

    Magnetic microtraps and Atom Chips are safe, small-scale, reliable and flexible tools to prepare ultra-cold and degenerate atom clouds as sources for various atom-optical experiments. We present an overview of the possibilities of the devices and indicate how a microtrap can be used to prepare and launch a Bose-Einstein condensate for use in an atom clock or an interferometer.