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Sample records for even-even nucleus shape

  1. Spin dependence of even-even nucleus shape in the model of Davydov-Chaban

    CERN Document Server

    Kashuba, I E

    2002-01-01

    The shape parameters of the even-even nuclei sup 1 sup 5 sup 4 Gd, sup 1 sup 5 sup 6 sup , sup 1 sup 5 sup 8 sup , sup 1 sup 6 sup 0 Dy, sup 1 sup 6 sup 4 sup , sup 1 sup 6 sup 8 Er, sup 1 sup 6 sup 8 Yb, sup 1 sup 7 sup 6 Hf, sup 1 sup 8 sup 0 W are calculated within the phenomenological model of the nonaxial soft by beta-oscillation deformed nucleus. The spin dependence of the softness, nonaxiality and energy factor is assumed

  2. Decay out of the yrast and excited highly-deformed bands in the even-even nucleus {sup 134}Nd

    Energy Technology Data Exchange (ETDEWEB)

    Petrache, C.M.; Bazzacco, D.; Lunardi, S. [Sezione di Padova (Italy)] [and others

    1996-12-31

    The resolving power achieved by the new generation of {gamma}-ray detector arrays allows now to observe transitions with intensities of the order of {approximately}10{sup {minus}3} of the population of the final residual nucleus, making therefore feasible the study of the very weakly populated excited bands built on the superdeformed (SD) minimum or of the decay out of the SD bands. As a matter of fact, numerous excited SD bands have been observed in the different regions of superdeformation, which led to a deeper understanding of the single-particle excitation in the second minimum. The first experimental breakthrough in the study of the decay out process has been achieved in the odd-even {sup 133,135}Nd nuclei of the A=130 mass region. There, the observation of the discrete linking transitions has been favored by the relatively higher intensity of the highly-deformed (HD) bands ({approximately}10%), as well as by the small excitation energy with respect to the yrast line in the decay-out region ({approximately}1 MeV). No discrete linking transitions have been so far observed in the A=80, 150 mass regions. The present results suggest that the decay out of the HD bands in {sup 134}Nd is triggered by the crossing with the N=4 [402]5/2{sup +} Nilsson orbital, that has a smaller deformation than the corresponding N=6 intruder configuration. The crossing favours the mixing with the ND rotational bands strongly enhancing the decay-out process and weakening the in-band transition strength. The HD band becomes fragmented and looses part of its character. The intensity of the decay-out transitions increases when the spin of the HD state decreases, indicating enhanced ND amplitude in the wavefunction when going down the band. Lifetime measurements of the HD bands are crucial to further elucidate the decay-out process.

  3. Shape coexistence measurements in even-even neutron-deficient polonium isotopes by Coulomb excitation, using REX-ISOLDE and the Ge MINIBALL array

    CERN Multimedia

    Butler, P; Bastin, B; Kruecken, R; Voulot, D; Rahkila, P J; Orr, N A; Srebrny, J; Grahn, T; Clement, E; Paul, E S; Gernhaeuser, R A; Dorsival, A; Diriken, J V J; Huyse, M L; Iwanicki, J S

    The neutron-deficient polonium isotopes with two protons outside the closed Z=82 shell represent a set of nuclei with a rich spectrum of nucleus structure phenomena. While the onset of the deformation in the light Po isotopes is well established experimentally, questions remain concerning the sign of deformation and the magnitude of the mixing between different configurations. Furthermore, controversy is present with respect to the transition from the vibrational-like character of the heavier Po isotopes to the shape coexistence mode observed in the lighter Po isotopes. We propose to study this transition in the even-mass neutron-deficient $^{198,200,202}$Po isotopes by using post-accelerated beams from REX-ISOLDE and "safe"-energy Coulomb excitation. $\\gamma$- rays will be detected by the MINIBALL array. The measurements of the Coulomb excitation differential cross section will allow us to deduce both the transition and diagonal matrix elements for these nuclei and, combined with lifetime measurements, the s...

  4. Phase Transitions in Even-Even Palladium Isotopes

    Directory of Open Access Journals (Sweden)

    Diab S. M.

    2009-01-01

    Full Text Available The positive and negative parity states of the even-even palladium isotopes were stud- ied within the frame work of the interacting boson approximation model (IBA-1. The energy spectra, potential energy surfaces, electromagnetic transition probabilities, back bending and staggering effect have been calculated. The potential energy surfaces show smooth transition from vibrational-like to gamma-soft and finally to rotational-like nu- clei. Staggering effectle, has been observed between the positive and negative parity states in palladium isotopes. The agreement between theoretical predictions and exper- imental values are fairly good.

  5. Search for α + core states in even-even Cr isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Souza, M.A. [Universidade de Sao Paulo, Instituto de Fisica, Sao Paulo, SP (Brazil); Instituto Federal de Educacao, Ciencia e Tecnologia de Sao Paulo, Departamento de Mecanica, Sao Paulo, SP (Brazil); Miyake, H. [Universidade de Sao Paulo, Instituto de Fisica, Sao Paulo, SP (Brazil)

    2017-07-15

    The α + core structure is investigated in even-even Cr isotopes from the viewpoint of the local potential model. The comparison of Q{sub α}/A values for even-even Cr isotopes and even-even A = 46, 54, 56, 58 isobars indicates that {sup 46}Cr and {sup 54}Cr are the most favorable even-even Cr isotopes for the α + core configuration. The ground state bands of the two Cr isotopes are calculated through a local α + core potential containing a nuclear term with (1 + Gaussian) x (W.S. + W.S.{sup 3}) shape. The calculated spectra give a very good description of most experimental {sup 46}Cr and {sup 54}Cr levels, including the 0{sup +} bandheads. The reduced α-widths, rms intercluster separations and B(E2) transition rates are determined for the ground state bands. The calculations reproduce the order of magnitude of the available experimental B(E2) values without using effective charges, indicate that the low-spin members of the ground state bands present a stronger α-cluster character, and point out that the {sup 46}Cr ground state band has a significant degree of α-clustering in comparison with {sup 44}Ti. The volume integral per nucleon pair and rms radius obtained for the α + {sup 50}Ti potential are consistent with those reported previously in the analysis of α elastic scattering on {sup 50}Ti. (orig.)

  6. Lifetime measurement of neutron-rich even-even molybdenum isotopes

    Science.gov (United States)

    Ralet, D.; Pietri, S.; Rodríguez, T.; Alaqeel, M.; Alexander, T.; Alkhomashi, N.; Ameil, F.; Arici, T.; Ataç, A.; Avigo, R.; Bäck, T.; Bazzacco, D.; Birkenbach, B.; Boutachkov, P.; Bruyneel, B.; Bruce, A. M.; Camera, F.; Cederwall, B.; Ceruti, S.; Clément, E.; Cortés, M. L.; Curien, D.; De Angelis, G.; Désesquelles, P.; Dewald, M.; Didierjean, F.; Domingo-Pardo, C.; Doncel, M.; Duchêne, G.; Eberth, J.; Gadea, A.; Gerl, J.; Ghazi Moradi, F.; Geissel, H.; Goigoux, T.; Goel, N.; Golubev, P.; González, V.; Górska, M.; Gottardo, A.; Gregor, E.; Guastalla, G.; Givechev, A.; Habermann, T.; Hackstein, M.; Harkness-Brennan, L.; Henning, G.; Hess, H.; Hüyük, T.; Jolie, J.; Judson, D. S.; Jungclaus, A.; Knoebel, R.; Kojouharov, I.; Korichi, A.; Korten, W.; Kurz, N.; Labiche, M.; Lalović, N.; Louchart-Henning, C.; Mengoni, D.; Merchán, E.; Million, B.; Morales, A. I.; Napoli, D.; Naqvi, F.; Nyberg, J.; Pietralla, N.; Podolyák, Zs.; Pullia, A.; Prochazka, A.; Quintana, B.; Rainovski, G.; Reese, M.; Recchia, F.; Reiter, P.; Rudolph, D.; Salsac, M. D.; Sanchis, E.; Sarmiento, L. G.; Schaffner, H.; Scheidenberger, C.; Sengele, L.; Singh, B. S. Nara; Singh, P. P.; Stahl, C.; Stezowski, O.; Thoele, P.; Valiente Dobon, J. J.; Weick, H.; Wendt, A.; Wieland, O.; Winfield, J. S.; Wollersheim, H. J.; Zielinska, M.; PreSPEC Collaboration

    2017-03-01

    Background: In the neutron-rich A ≈100 mass region, rapid shape changes as a function of nucleon number as well as coexistence of prolate, oblate, and triaxial shapes are predicted by various theoretical models. Lifetime measurements of excited levels in the molybdenum isotopes allow the determination of transitional quadrupole moments, which in turn provides structural information regarding the predicted shape change. Purpose: The present paper reports on the experimental setup, the method that allowed one to measure the lifetimes of excited states in even-even molybdenum isotopes from mass A =100 up to mass A =108 , and the results that were obtained. Method: The isotopes of interest were populated by secondary knock-out reaction of neutron-rich nuclei separated and identified by the GSI fragment separator at relativistic beam energies and detected by the sensitive PreSPEC-AGATA experimental setup. The latter included the Lund-York-Cologne calorimeter for identification, tracking, and velocity measurement of ejectiles, and AGATA, an array of position sensitive segmented HPGe detectors, used to determine the interaction positions of the γ ray enabling a precise Doppler correction. The lifetimes were determined with a relativistic version of the Doppler-shift-attenuation method using the systematic shift of the energy after Doppler correction of a γ -ray transition with a known energy. This relativistic Doppler-shift-attenuation method allowed the determination of mean lifetimes from 2 to 250 ps. Results: Even-even molybdenum isotopes from mass A =100 to A =108 were studied. The decays of the low-lying states in the ground-state band were observed. In particular, two mean lifetimes were measured for the first time: τ =29 .7-9.1+11.3 ps for the 4+ state of 108Mo and τ =3 .2-0.7+0.7 ps for the 6+ state of 102Mo. Conclusions: The reduced transition strengths B (E 2 ) , calculated from lifetimes measured in this experiment, compared to beyond

  7. Predicting the optical observables for nucleon scattering on even-even actinides

    Science.gov (United States)

    Martyanov, D. S.; Soukhovitskiĩ, E. Sh.; Capote, R.; Quesada, J. M.; Chiba, S.

    2017-09-01

    The previously derived Lane consistent dispersive coupled-channel optical model for nucleon scattering on 232Th and 238U nuclei is extended to describe scattering on even-even actinides with Z = 90-98. A soft-rotator-model (SRM) description of the low-lying nuclear structure is used, where the SRM Hamiltonian parameters are adjusted to the observed collective levels of the target nucleus. SRM nuclear wave functions (mixed in K quantum number) have been used to calculate the coupling matrix elements of the generalized optical model. The “effective” deformations that define inter-band couplings are derived from the SRM Hamiltonian parameters. Conservation of nuclear volume is enforced by introducing a dynamic monopolar term to the deformed potential, leading to additional couplings between rotational bands. The fitted static deformation parameters are in very good agreement with those derived by Wang and collaborators using the Weizsäcker-Skyrme global mass model (WS4), allowing use of the latter to predict cross sections for nuclei without experimental data. A good description of the scarce “optical” experimental database is achieved. SRM couplings and volume conservation allow a precise calculation of the compound-nucleus formation cross sections, which is significantly different from that calculated with rigid-rotor potentials coupling the ground-state rotational band. The derived parameters can be used to describe both neutron- and proton-induced reactions. Supported by International Atomic Energy Agency, through the IAEA Research Contract 19263, by the Spanish Ministry of Economy and Competitivity under Contracts FPA2014-53290-C2-2-P and FPA2016-77689-C2-1-R.

  8. Low-lying collective quadrupole and octupole strengths in even-even nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Raman, S.; Nestor, C.W. Jr. (Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (US)); Kahane, S. (Joint Institute for Heavy-Ion Research, Holifield Heavy Ion Research Facility, Oak Ridge, Tennessee 37831 (USA)); Bhatt, K.H. (Department of Physics and Astronomy, University of Mississippi, University, Mississipi 38677 (USA))

    1991-02-01

    The {ital B}({ital E}2){up arrow} values for the first 2{sup +} state of even-even nuclei in the {ital Z}{ge}50 region are compared with the predictions of several theoretical models. Comparative estimates of the overall agreement with the data are provided. Gaps and discrepancies in the data and examples that show interesting features such as shape changes are discussed. The {ital B}({ital E}2){up arrow} values are examined critically to search for the dynamical Pauli effects predicted by the fermion dynamic symmetry model. The empirical {ital B}({ital E}2){up arrow} and {ital B}({ital E}3){up arrow} systematics are employed to obtain a measure of the harmonicity of the quadrupole and octupole vibrations. The fraction of the energy-weighted sum-rule strength exhausted by the sum of all known low-lying 2{sup +} states below 2.3 MeV is found to be surprisingly constant in the 60{lt}{ital A}{lt}250 region except near closed shells.

  9. Systematic study of even-even nuclei with Hartree-Fock+BCS method using Skyrme SIII force

    Energy Technology Data Exchange (ETDEWEB)

    Tajima, Naoki; Takahara, Satoshi; Onishi, Naoki [Tokyo Univ. (Japan). Coll. of Arts and Sciences

    1997-03-01

    We have applied the Hartree-Fock+BCS method with Skyrme SIII force formulated in a three-dimensional Cartesian-mesh representation to even-even nuclei with 2 {<=} Z {<=} 114. We discuss the results concerning the atomic masses, the quadrupole (m=0, 2) and hexadecapole (m=0, 2, 4) deformations, the skin thicknesses, and the halo radii. We also discuss the energy difference between oblate and prolate solutions and the shape difference between protons and neutrons. (author)

  10. Descriptive study of the even-even actinide nuclei 230 - 234Th isotopes using IBM-1

    Science.gov (United States)

    Al-Dahan, N.

    2017-06-01

    The nuclear structure of the actinide even-even thorium isotopes from A=230-234 have been investigated within the framework of the Interacting Boson Model (IBM-1). Predictions are given for the excited state energies for the ground state, β and γ-bands, the transition probabilities between these states, the rotational moment of inertia, and the energy staggering in the γ-band energies. The results of these calculations are compared with the experimental data on these isotopes.

  11. Nature of the Excited States of the Even-Even 98-108 Ru Isotopes

    Directory of Open Access Journals (Sweden)

    Eid S. A.

    2008-10-01

    Full Text Available The positive and negative parity states of the even-even 98-108 Ru isotopes are studied within the frame work of the interacting boson approximation model (IBA-1. The calculated levels energy, potential energy surfaces, $V(eta,gamma$, and the electromagnetic transition probabilities, B(E1 and B(E2, show that ruthenium isotopes are transitional nuclei. Staggering effectle, $Delta I = 1$, has been observed between the positive and negative parity states in some of ruthenium isotopes. The electric monopole strength, X(E0/E2, has been calculated. All calculated values are compared with the available experimental and theoretical data wher reasonable agreement has obtained.

  12. Structure of Even-Even 218-230 Ra Isotopes within the Interacting Boson Approximation Model

    OpenAIRE

    Diab S. M.

    2008-01-01

    A good description of the excited positive and negative parity states of radium nuclei (Z=88, N=130-142) is achieved using the interacting boson approximation model (IBA-1). The potential energy surfaces, energy levels, parity shift, electromagnetic transition rates B(E1), B(E2) and electric monopole strength X(E0/E2) are calculated for each nucleus. The analysis of the eigenvalues of the model Hamiltonian reveals the presence of an interaction between the positive and negative parity bands. ...

  13. Structure of Even-Even 218-230 Ra Isotopes within the Interacting Boson Approximation Model

    Directory of Open Access Journals (Sweden)

    Diab S. M.

    2008-01-01

    Full Text Available A good description of the excited positive and negative parity states of radium nuclei (Z=88, N=130-142 is achieved using the interacting boson approximation model (IBA-1. The potential energy surfaces, energy levels, parity shift, electromagnetic transition rates B(E1, B(E2 and electric monopole strength X(E0/E2 are calculated for each nucleus. The analysis of the eigenvalues of the model Hamiltonian reveals the presence of an interaction between the positive and negative parity bands. Due to this interaction the $Delta I = 1$ staggering effect, between the energies of the ground state band and the negative parity state band, is produced including beat patterns.

  14. Symmetries of Quadrupole-Collective Vibrational Motion in Transitional Even-Even 124−134Xenon Nuclei

    CERN Document Server

    Pietralla, N; Rainovski, G; Ahn, T; Bauer, C; Leske, J; Möller, O; Möller, T

    2010-01-01

    Projectile-Coulomb excitation of Xe isotopes has been performed at ANL using the Gammasphere array for the detection of γ-rays. The one-quadrupole phonon 2+ 1,ms mixed-symmetry state (MSS) has been traced in the stable N=80 isotones down to 134Xe. First, the data on absolute E2 andM1 transition rates quantify the amount of F-spin symmetry in these nuclei and provide a new local measure for the pn-QQ interaction. Second, the evolution of the 2+ 1,ms state has been studied along the sequence of stable even-even 124−134Xe isotopes that are considered to form a shape transition path from vibrational nuclei with vibrational U(5) symmetry near N=82 to γ-softly deformed shapes with almost O(6) symmetry. Third, our data on more than 50 absolute E2 transition rates between off-yrast low-spin states of 124,126Xe enable us to quantitatively test O(6) symmetry in these nuclei. As a result we find that O(6) symmetry is more strongly broken in the A=130 mass region than previously thought. The data will be discussed.

  15. A systematic study of even-even nuclei in the nuclear chart by the relativistic mean field theory

    Energy Technology Data Exchange (ETDEWEB)

    Sumiyoshi, K.; Hirata, D.; Tanihata, I.; Sugahara, Y.; Toki, H. [Institute of Physical and Chemical Research, Wako, Saitama (Japan)

    1997-03-01

    We study systematically the properties of nuclei in the whole mass range up to the drip lines by the relativistic mean field (RMF) theory with deformations as a microscopic framework to provide the data of nuclear structure in the nuclear chart. The RMF theory is a phenomenological many-body framework, in which the self-consistent equations for nucleons and mesons are solved with arbitrary deformation, and has a potential ability to provide all the essential information of nuclear structure such as masses, radii and deformations together with single particle states and wave functions from the effective lagrangian containing nuclear interaction. As a first step toward the whole project, we study the ground state properties of even-even nuclei ranging from Z=8 to Z=120 up to the proton and neutron drip lines in the RMF theory. We adopt the parameter set TMA, which has been determined by the experimental masses and charge radii in a wide mass range, for the effective lagrangian of the RMF theory. We take into account the axially symmetric deformation using the constrained method on the quadrupole moment. We provide the properties of all even-even nuclei with all the possible ground state deformations extracted from the deformation energy curves by the constrained calculations. By studying the calculated ground state properties systematically, we aim to explore the general trend of masses, radii and deformations in the whole region of the nuclear chart. We discuss the agreement with experimental data and the predictions such as magicness and triaxial deformations beyond the experimental frontier. (author)

  16. Coulomb form factors of even-even nuclei described by axially deformed relativistic mean-field models

    Science.gov (United States)

    Liu, Jian; Xu, Chang; Ren, Zhongzhou

    2017-04-01

    Background: Combining the relativistic mean-field (RMF) model and distorted wave Born approximation (DWBA) method, Coulomb form factors for elastic electron scattering have been studied for several stable nuclei (208Pb, 40Ca, 32S, and 24Mg) with a methodology that can be extended to exotic nuclei. Purpose: Previous studies on nuclear Coulomb form factors by the RMF+DWBA method were mainly based on the spherical RMF model. This work aims to further extend the studies to the axially deformed RMF model. Method: The nuclear proton density distributions are first calculated by the deformed RMF model. Next, the axially deformed density distributions are expanded into multipole components. With the spherical ρ0 components, the Coulomb form factors of even-even nuclei are calculated by the DWBA method. Results: For spherical nuclei, the nuclear Coulomb form factors obtained with the deformed RMF model almost coincide with those from the spherical RMF model. For deformed nuclei, Coulomb form factors obtained with the deformed RMF model agree better with the experimental data at the diffraction minima and at high momentum transfers. Conclusions: Results indicate the proton densities calculated from the axially deformed RMF model are valid and reasonable. The electron-scattering experiments will soon be available for exotic nuclei, and the studies in this paper are helpful to interpret the experimental data of deformed exotic nuclei.

  17. Microscopic description of the even-even 140-148Ba isotopes using BM, IBM and IVBM

    Science.gov (United States)

    Ahmed, Imad M.; Flaiyh, Ghaith N.; Kassim, Huda H.; Abdullah, Hewa Y.; Hossain, I.; Sharrad, Fadhil I.

    2017-02-01

    A description of the even-even Ba isotopes for A = 140 to 148 in framework of Bohr-Mottelson model, interacting boson model and interacting vector boson model are carried out. The E-GOS curve ( E γ/ I and the ratio between the energies of the ( I + 2) and ( I) states ( r( I + 2)/ I) as a function of the spin ( I have been drawn to determine the property of the ground-state band. The positive ground-state band of 140-148Ba has been calculated using Bohr-Mottelson model, interacting boson model and interacting vector boson model, while the negative-parity band of 140-148Ba has been calculated using Bohr-Mottelson model and interacting vector boson model only. The reduced transition probabilities B( E2) of these nuclei were calculated. The parameters of the best fit to the measured data are determined. The potential energy surfaces (PESs) to the IBM Hamiltonian have been obtained using the intrinsic coherent state.

  18. The Structure of Even-Even 218-230 Ra Isotopes within the Interacting Boson Approximation Model

    OpenAIRE

    Diab S. M.

    2008-01-01

    A good description of the excited positive and negative parity states of radium nuclei ( Z = 88, N = 130–142) is achieved using the interacting boson approximation model (IBA-1). The potential energy surfaces, energy levels, parity shift, electromagnetic tran- sition rates B ( E 1) , B ( E 2) and electric monopole strength X ( E 0 / E 2 ) are calculated for each nucleus. The analysis of the eigenvalues of the ...

  19. Unique first-forbidden β-decay transitions in odd-odd and even-even heavy nuclei

    Science.gov (United States)

    Nabi, Jameel-Un; Çakmak, Necla; Majid, Muhammad; Selam, Cevad

    2017-01-01

    The allowed Gamow-Teller (GT) transitions are the most common weak nuclear processes of spin-isospin (στ) type. These transitions play a key role in numerous processes in the domain of nuclear physics. Equally important is their contribution in astrophysics, particularly in nuclear synthesis and supernova-explosions. In situations where allowed GT transitions are not favored, first-forbidden transitions become significant, specifically in medium heavy and heavy nuclei. For neutron-rich nuclei, first-forbidden transitions are favored mainly due to the phase-space amplification for these transitions. In this work we calculate the allowed GT as well as unique first-forbidden (U1F) | ΔJ | = 2 transitions strength in odd-odd and even-even nuclei in mass range 70 ≤ A ≤ 214. Two different pn-QRPA models were used with a schematic separable interaction to calculate GT and U1F transitions. The inclusion of U1F strength improved the overall comparison of calculated terrestrial β-decay half-lives in both models. The ft values and reduced transition probabilities for the 2- ⟷0+ transitions were also calculated. We compared our calculations with the previously reported correlated RPA calculation and experimental results. Our calculations are in better agreement with measured data. For stellar applications we further calculated the allowed GT and U1F weak rates. These include β±-decay rates and electron/positron capture rates of heavy nuclei in stellar matter. Our study shows that positron and electron capture rates command the total weak rates of these heavy nuclei at high stellar temperatures.

  20. Shape study of the N=Z waiting-point nucleus 72Kr via beta decay

    CERN Document Server

    Briz Monago, Jose Antonio; Nácher González, Enrique

    The Ph.D. thesis entitled “Shape study of the N=Z waiting-point nucleus 72Kr via beta decay” is devoted to the study of the shape of the ground state of the 72Kr nucleus. It is an N=Z nucleus in the mass region A~70-80 where shape transitions and the shape coexistence phenomena have been identified. Furthermore, this nucleus participates in the rp-process as a waiting point due to the slowdown of the process taking place at the arrival to this nucleus. The study of the properties of this nucleus is interesting from the Nuclear Structure point of view, for the phenomena occurring in its mass region and have been predicted for it, and from the Nuclear Astrophysics for the accurate performance of astrophysical calculations. The β+/EC decay of the 72Kr nucleus has been studied through two complementary experiments at the ISOLDE facility at CERN in Geneva (Switzerland). In one of them, the low-spin structure of the daughter nucleus, 72Br, has been revised via conversion electron spectroscopy where the convers...

  1. The Structure of Even-Even 218-230 Ra Isotopes within the Interacting Boson Approximation Model

    Directory of Open Access Journals (Sweden)

    Diab S. M.

    2008-01-01

    Full Text Available A good description of the excited positive and negative parity states of radium nuclei ( Z = 88, N = 130–142 is achieved using the interacting boson approximation model (IBA-1. The potential energy surfaces, energy levels, parity shift, electromagnetic tran- sition rates B ( E 1 , B ( E 2 and electric monopole strength X ( E 0 / E 2 are calculated for each nucleus. The analysis of the eigenvalues of the model Hamiltonian reveals the presence of an interaction between the positive and negative parity bands. Due to this interaction the I = 1 staggering e ect, between the energies of the ground state band and the negative parity state band, is produced including beat patterns.

  2. Shaping Chromatin in the Nucleus: The Bricks and the Architects.

    Science.gov (United States)

    Sitbon, David; Podsypanina, Katrina; Yadav, Tejas; Almouzni, Geneviève

    2017-12-05

    Chromatin organization in the nucleus provides a vast repertoire of information in addition to that encoded genetically. Understanding how this organization impacts genome stability and influences cell fate and tumorigenesis is an area of rapid progress. Considering the nucleosome, the fundamental unit of chromatin structure, the study of histone variants (the bricks) and their selective loading by histone chaperones (the architects) is particularly informative. Here, we report recent advances in understanding how relationships between histone variants and their chaperones contribute to tumorigenesis using cell lines and Xenopus development as model systems. In addition to their role in histone deposition, we also document interactions between histone chaperones and other chromatin factors that govern higher-order structure and control DNA metabolism. We highlight how a fine-tuned assembly line of bricks (H3.3 and CENP-A) and architects (HIRA, HJURP, and DAXX) is key in adaptation to developmental and pathological changes. An example of this conceptual advance is the exquisite sensitivity displayed by p53-null tumor cells to modulation of HJURP, the histone chaperone for CENP-A (CenH3 variant). We discuss how these findings open avenues for novel therapeutic paradigms in cancer care. © 2017 Sitbon et al.; Published by Cold Spring Harbor Laboratory Press.

  3. Shape and Size of the Fission Yeast Nucleus are governed by Equilibrium Mechanics

    Science.gov (United States)

    Lim, Gerald; Huber, Greg; Miller, Jonathan; Sazer, Shelley

    2006-03-01

    Nuclear morphogenesis in the asexual reproduction of Schizosaccharomyces pombe (fission yeast) consists of two stages: (i) volume-doubling growth, in which a round nucleus inflates uniformly, and (ii) division, in which the nucleus undergoes shape changes from round to oblong to peanut to dumbbell before it resolves into two smaller, round daughter nuclei, driven by the formation and elongation of a microtubule-based spindle within the nucleus. The combined volume of the daughter nuclei immediately after division is the same as the volume of the single nucleus at the onset of division. Consequently, the nuclear envelope (NE) area must increase by 26% during division. We are developing a model in order to determine the mechanics governing these shape and size changes. It is based on current knowledge of the nuclear structure, insight from normal and abnormal nuclei, and concepts from the mechanics governing lipid-bilayer membranes. We predict that (a) the NE prefers to be flat, (b) the NE is under tension, (c) the nucleus has an internal pressure, (d) nuclear growth is governed by the Law of Laplace, and (e) some abnormal nuclei behave like vesicles with encapsulated microtubules.

  4. Shell model description of E 3 transition strengths from the first 3- states in s d -shell even-even nuclei

    Science.gov (United States)

    Bouhelal, M.; Labidi, M.; Haas, F.; Caurier, E.

    2017-10-01

    The electric-octupole E 3 transition strengths from the first 3- state to the ground-state transition in s d shell even-even nuclei with A =16 to 40 are investigated within the shell model framework using the effective (0+1)ℏ ω PSDPF interaction. For this type of transition, new effective charges for protons and neutrons have been determined. Their values 1.36 e for protons and 0.48 e for neutrons are close to those obtained previously for electric-quadrupole E 2 transitions in s d shell nuclei. The calculated E 3 transition strengths from the 31 -→0gs + transitions are compared to a compilation of experimental E 3 data for even-even nuclei throughout the s d shell.

  5. New shape isomer in the self-conjugate nucleus 72Kr.

    Science.gov (United States)

    Bouchez, E; Matea, I; Korten, W; Becker, F; Blank, B; Borcea, C; Buta, A; Emsallem, A; de France, G; Genevey, J; Hannachi, F; Hauschild, K; Hürstel, A; Le Coz, Y; Lewitowicz, M; Lucas, R; Negoita, F; de Oliveira Santos, F; Pantelica, D; Pinston, J; Rahkila, P; Rejmund, M; Stanoiu, M; Theisen, Ch

    2003-02-28

    A new isomeric 0(+) state was identified as the first excited state in the self-conjugate (N=Z) nucleus 72Kr. By combining for the first time conversion-electron and gamma-ray spectroscopy with the production of metastable states in high-energy fragmentation, the electric-monopole decay of the new isomer to the ground state was established. The new 0(+) state is understood as the band head of the known prolate rotational structure, which strongly supports the interpretation that 72Kr is one of the rare nuclei having an oblate-deformed ground state. This observation gives in fact the first evidence for a shape isomer in a N=Z nucleus.

  6. Circular shape constrained fuzzy clustering (CiscFC) for nucleus segmentation in Pap smear images.

    Science.gov (United States)

    Saha, Ratna; Bajger, Mariusz; Lee, Gobert

    2017-06-01

    Accurate detection and segmentation of cell nucleus is the precursor step towards computer aided analysis of Pap smear images. This is a challenging and complex task due to degree of overlap, inconsistent staining and poor contrast. In this paper, a novel nucleus segmentation method is proposed by incorporating a circular shape function in fuzzy clustering. The proposed method was evaluated quantitatively and qualitatively using the Overlapping Cervical Cytology Image Segmentation Challenge - ISBI 2014 challenge dataset comprised of 945 overlapping Pap smear images. It achieved superior performance in terms of Dice similarity coefficient of 0.938, pixel-based recall 0.939 and object based precision 0.968. The results were compared with the standard fuzzy c-means (FCM) clustering, ISBI 2014 challenge submissions and recent state-of-the-art methods. The outcome shows that the new approach can produce more accurate nucleus boundaries while keeping high level of precision and recall. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Apathy in Parkinson's disease is associated with nucleus accumbens atrophy: a magnetic resonance imaging shape analysis.

    Science.gov (United States)

    Carriere, Nicolas; Besson, Pierre; Dujardin, Kathy; Duhamel, Alain; Defebvre, Luc; Delmaire, Christine; Devos, David

    2014-06-01

    Apathy is characterized by lack of interest, loss of initiative, and flattening of affect. It is a frequent, very disabling nonmotor complication of Parkinson's disease (PD). The condition may notably occur when dopaminergic medications are tapered after the initiation of subthalamic stimulation and thus can be referred to as "dopaminergic apathy." Even in the absence of tapering, some patients may develop a form of apathy as PD progresses. This form is often related to cognitive decline and does not respond to dopaminergic medications (dopa-resistant apathy). We aimed at determining whether dopa-resistant apathy in PD is related to striatofrontal morphological changes. We compared the shape of the striatum (using spherical harmonic parameterization and sampling in a three-dimensional point distribution model [SPHARM-PDM]), cortical thickness, and fractional anisotropy (using tract-based spatial statistics) in 10 consecutive patients with dopamine-refractory apathy, 10 matched nonapathetic PD patients and 10 healthy controls. Apathy in PD was associated with atrophy of the left nucleus accumbens. The SPHARM-PDM analysis highlighted (1) a positive correlation between the severity of apathy and atrophy of the left nucleus accumbens, (2) greater atrophy of the dorsolateral head of the left caudate in apathetic patients than in nonapathetic patients, and (3) greater atrophy in the bilateral nucleus accumbens in apathetic patients than in controls. There were no significant intergroup differences in cortical thickness or fractional anisotropy. Dopa-resistant apathy in PD was associated with atrophy of the left nucleus accumbens and the dorsolateral head of the left caudate. © 2014 International Parkinson and Movement Disorder Society.

  8. Description of nuclear systems with a self-consistent configuration-mixing approach. II. Application to structure and reactions in even-even s d -shell nuclei

    Science.gov (United States)

    Robin, C.; Pillet, N.; Dupuis, M.; Le Bloas, J.; Peña Arteaga, D.; Berger, J.-F.

    2017-04-01

    Background: The variational multiparticle-multihole configuration mixing approach to nuclei has been proposed about a decade ago. While the first applications followed rapidly, the implementation of the full formalism of this method has only been recently completed and applied in C. Robin, N. Pillet, D. Peña Arteaga, and J.-F. Berger, [Phys. Rev. C 93, 024302 (2016)], 10.1103/PhysRevC.93.024302 to 12C as a test-case. Purpose: The main objective of the present paper is to carry on the study that was initiated in that reference, in order to put the variational multiparticle-multihole configuration mixing method to more stringent tests. To that aim we perform a systematic study of even-even s d -shell nuclei. Method: The wave function of these nuclei is taken as a configuration mixing built on orbitals of the s d -shell, and both the mixing coefficients of the nuclear state and the single-particle wave functions are determined consistently from the same variational principle. As in the previous works, the calculations are done using the D1S Gogny force. Results: Various ground-state properties are analyzed. In particular, the correlation content and composition of the wave function as well as the single-particle orbitals and energies are examined. Binding energies and charge radii are also calculated and compared to experiment. The description of the first excited state is also examined and the corresponding transition densities are used as input for the calculation of reaction processes such as inelastic electron and proton scattering. Special attention is paid to the effect of the optimization of the single-particle states consistently with the correlations of the system. Conclusions: The variational multiparticle-multihole configuration mixing approach is systematically applied to the description of even-even s d -shell nuclei. Globally, the results are satisfying and encouraging. In particular, charge radii and excitation energies are nicely reproduced. However

  9. DNA Cross-Bridging Shapes a Single Nucleus from a Set of Mitotic Chromosomes.

    Science.gov (United States)

    Samwer, Matthias; Schneider, Maximilian W G; Hoefler, Rudolf; Schmalhorst, Philipp S; Jude, Julian G; Zuber, Johannes; Gerlich, Daniel W

    2017-08-24

    Eukaryotic cells store their chromosomes in a single nucleus. This is important to maintain genomic integrity, as chromosomes packaged into separate nuclei (micronuclei) are prone to massive DNA damage. During mitosis, higher eukaryotes disassemble their nucleus and release individualized chromosomes for segregation. How numerous chromosomes subsequently reform a single nucleus has remained unclear. Using image-based screening of human cells, we identified barrier-to-autointegration factor (BAF) as a key factor guiding membranes to form a single nucleus. Unexpectedly, nuclear assembly does not require BAF's association with inner nuclear membrane proteins but instead relies on BAF's ability to bridge distant DNA sites. Live-cell imaging and in vitro reconstitution showed that BAF enriches around the mitotic chromosome ensemble to induce a densely cross-bridged chromatin layer that is mechanically stiff and limits membranes to the surface. Our study reveals that BAF-mediated changes in chromosome mechanics underlie nuclear assembly with broad implications for proper genome function. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  10. Shape Abnormalities of the Caudate Nucleus Correlate with Poorer Gait and Balance

    DEFF Research Database (Denmark)

    Macfarlane, Matthew D; Looi, Jeffrey C L; Walterfang, Mark

    2015-01-01

    found to correlate with poorer performance on measures of gait and balance. This study aimed to determine whether striatal volume and shape changes were correlated with gait dysfunction. METHODS: Magnetic resonance imaging scans and clinical gait/balance data (scores from the Short Physical Performance...... published method and volumes calculated. The relationships between volume and physical performance on the SPPB were investigated with shape analysis using the spherical harmonic shape description toolkit. RESULTS: There was no correlation between the severity of WMHs and striatal volumes. Caudate nuclei...... volume correlated with performance on the SPPB at baseline but not at follow-up, with subsequent shape analysis showing left caudate changes occurred in areas corresponding to inputs of the dorsolateral prefrontal, premotor, and motor cortex. There was no correlation between putamen volumes...

  11. The Nucleus of Comet 9P-Tempel 1: Shape and Geology from Two Flybys

    Science.gov (United States)

    Thomas, P.; A'Hearn, M.; Belton, M. J. S.; Brownlee, D.; Carcich, B.; Hermalyn, B.; Klaasen, K.; Sackett, S.; Schultz, P. H.; Veverka, J.; hide

    2012-01-01

    The nucleus of comet Tempel 1 has been investigated at close range during two spacecraft missions separated by one comet orbit of the Sun, 5 1/2 years. The combined imaging covers 70% of the surface of this object which has a mean radius of 2.83 +/- 0.1 km. The surface can be divided into two terrain types: rough, pitted terrain and smoother regions of varying local topography. The rough surface has round depressions from resolution limits (10 m/pixel) up to 1 km across, spanning forms from crisp steep-walled pits, to subtle albedo rings, to topographic rings, with all ranges of morphologic gradation. Three gravitationally low regions of the comet have smoother terrain, parts of which appear to be deposits from minimally modified flows, with other parts likely to be heavily eroded portions of multiple layer piles. Changes observed between the two missions are primarily due to backwasting of scarps bounding one of these probable flow deposits. This style of erosion is also suggested by remnant mesa forms in other areas of smoother terrain. The two distinct terrains suggest either an evolutionary change in processes, topographically- controlled processes, or a continuing interaction of erosion and deposition.

  12. Shape, Density, and Geology of the Nucleus of Comet 103P/Hartley 2

    Science.gov (United States)

    Thomas, P.C.; A'hearn, Michael F.; Veverka, Joseph; Belton, Michael J. S.; Kissel, Jochen; Belton, Michael J. S.; Klaasen, Kenneth P.; McFadden, Lucy A.; Melosh, H. Jay; Schultz, Peter H.; hide

    2013-01-01

    Data from the Extrasolar Planet Observation and Deep Impact Extended Investigation (EPOXI) mission show Comet 103P/Hartley 2 is a bi-lobed, elongated, nearly axially symmetric comet 2.33 km in length. Surface features are primarily small mounds 1%. The shape may be the evolutionary product of insolation, sublimation, and temporary deposition of materials controlled by the object’s complex rotation.

  13. Lifetime measurements of intruder states in sup 120 Xe and the shape coexistence picture

    Energy Technology Data Exchange (ETDEWEB)

    Bhagwat, A.; Walker, P.M.; Singleton, B.D.D. (Surrey Univ., Guildford (United Kingdom). Dept. of Physics); Al-Ghamdi, S.S.; Barham, C.G.; Grant, I.S. (Manchester Univ. (United Kingdom). Schuster Lab.)

    1992-05-01

    Absolute EO and E2 transition rates have been measured for the O{sub 3}{sup +} state in {sup 120}Xe. The O{sub 3}{sup +} state appears to be weakly mixed with the normal structure of {sup 120}Xe. In the N = 66 mid-neutron-shell region, this is the heaviest even-even nucleus showing a signature of shape coexistence. (author).

  14. Objective assessment of contact lens wear-associated conjunctival squamous metaplasia by linear measures of cell size, shape and nucleus-to-cytoplasm ratios.

    Science.gov (United States)

    Doughty, Michael J

    2011-07-01

    To objectively assess the cell and nucleus dimensions of human bulbar conjunctival cells in female soft contact lens wearers to illustrate a method for assessment of the nucleus-to-cytoplasm ratio based on simple linear measures. Impression cytology samples were taken from the nasal side exposed bulbar conjunctiva surface from 12 young adult, white European females with a history of successful daily soft contact lens wear. A Millcell(®)-CM filter was used after topical anesthesia, which was stained with Giemsa. Color images of portions of the cells, in a monolayer at 200× magnification by light microscopy, were graded by the Nelson scale and then a projection overlay method was used to outline the cell and nucleus borders. The cell longest dimension (LONG), shorter dimension (SHORT), and the longest dimension of the nucleus (NUCLONG) were measured. A nucleus-to-cytoplasm N:C ratio was calculated from (LONG-NUCLONG)/NUCLONG. Cells had appearances consistent with a grade 2 or 3 squamous metaplasia and were moderately enlarged (mean LONG ± SD of 46.0 ± 3.8 microm), only slightly elongated (mean LONG:SHORT ratio of 1.397 ± 0.101) and the nucleus size was consistently greater than normal (man 12.8 ± 1.3 microm). A calculation of N:C showed a relatively wide range of values with average values from 1:2.143 to 1:3.317 (for an overall mean of 2.675 ± 0.371). These studies further indicate that grade 2 to 3 squamous metaplasia of the exposed bulbar conjunctival cells is an expected consequence of soft contact lens wear. The cell enlargement is not associated with a significant change in cell shape (i.e., the LONG:SHORT ratio is little different from grade 0 cells) but is associated in a slight increase in nucleus size. The calculated N:C ratio based on linear measures is no higher than 1:5 and more likely closer to 1:2.5.

  15. A Heuristic Image Search Algorithm for Active Shape Model Segmentation of the Caudate Nucleus and Hippocampus in Brain MR Images of Children with FASD

    Directory of Open Access Journals (Sweden)

    A A Eicher

    2012-09-01

    Full Text Available Magnetic Resonance Imaging provides a non-invasive means to study the neural correlates of Fetal Alcohol Spectrum Disorder (FASD - the most common form of preventable mental retardation worldwide. One approach aims to detect brain abnormalities through an assessment of volume and shape of two sub-cortical structures, the caudate nucleus and hippocampus. We present a method for automatically segmenting these structures from high-resolution MR images captured as part of an ongoing study into the neural correlates of FASD. Our method incorporates an Active Shape Model, which is used to learn shape variation from manually segmented training data. A modified discrete Geometrically Deformable Model is used to generate point correspondence between training models. An ASM is then created from the landmark points. Experiments were conducted on the image search phase of ASM segmentation, in order to find the technique best suited to segmentation of the hippocampus and caudate nucleus. Various popular image search techniques were tested, including an edge detection method and a method based on grey profile Mahalanobis distance measurement. A novel heuristic image search method was also developed and tested. This heuristic method improves image segmentation by taking advantage of characteristics specific to the target data, such as a relatively homogeneous tissue colour in target structures. Results show that ASMs that use the heuristic image search technique produce the most accurate segmentations. An ASM constructed using this technique will enable researchers to quickly, reliably, and automatically segment test data for use in the FASD study.

  16. Systematics of even-even T{sub z}= 1 nuclei in the A= 80 region: High-spin rotational bands in {sup 74}Kr, {sup 78}Sr, and {sup 82}Zr

    Energy Technology Data Exchange (ETDEWEB)

    Rudolph, D.; Baktash, C.; Gross, C.J.; Jin, H.; Yu, C.H. [Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Rudolph, D. [Sektion Physik der Ludwig-Maximilians-Universitaet Muenchen, D-85748 Garching (Germany); Gross, C.J. [Oak Ridge Institute for Science and Education, Oak Ridge, Tennessee 37831 (United States); Satula, W. [Department of Physics, University of Tennessee, Knoxville, Tennessee 37996 (United States); Satula, W. [Joint Institute for Heavy Ion Research, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Satula, W. [Institute of Theoretical Physics, Warsaw University, PL-00681 Warsaw (Poland); Wyss, R. [The Royal Institute of Technology, Physics Department Frescati, S-104 05 Stockholm (Sweden); Birriel, I.; Saladin, J.X.; Winchell, D.F.; Wood, V.Q. [Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania 15260 (United States); Devlin, M.; LaFosse, D.R.; Lerma, F.; Sarantites, D.G. [Chemistry Department, Washington University, St. Louis, Missouri 63130 (United States); Sylvan, G.N.; Tabor, S.L. [Department of Physics, Florida State University, Tallahassee, Florida 32306 (United States)

    1997-07-01

    High-spin states of T{sub z}=1 nuclei were studied with the reactions {sup 58}Ni({sup 28}Si,3{alpha}){sup 74}Kr, {sup 58}Ni({sup 28}Si,2{alpha}){sup 78}Sr, and {sup 58}Ni({sup 28}Si,2p2n){sup 82}Zr at 130 MeV beam energy. The Gammasphere array in conjunction with the 4{pi} charged-particle detector array Microball was used to detect {gamma} rays in coincidence with evaporated light charged particles. The known {pi}=+, {alpha}=0 yrast bands were extended to I=28{h_bar} at 20 MeV excitation energy. For all three nuclei, a number of positive- and negative-parity sidebands were established; altogether 15 new rotational bands were found. The data are discussed using the pairing-and-deformation self-consistent total Routhian surface (TRS) model: High-spin structures of {sup 74}Kr and {sup 78}Sr are governed by the shell gaps at large prolate deformation while {sup 82}Zr seems to exhibit shape coexistence. Nearly identical bands were established which may be explained as arising from the fp orbits acting as spectators at very elongated shapes. The experimental data in these T{sub z}=1 nuclei are in good agreement with predictions of the TRS model using conventional T=1 like-nucleon pairing correlations. {copyright} {ital 1997} {ital The American Physical Society}

  17. Auditory input shapes tonotopic differentiation of Kv1.1 expression in avian cochlear nucleus during late development.

    Science.gov (United States)

    Akter, Nargis; Adachi, Ryota; Kato, Akitoshi; Fukaya, Ryota; Kuba, Hiroshi

    2018-02-08

    Tonotopic differentiation is fundamental for signal processing in the auditory system. However, when and how this differentiation arises remains elusive. We addressed this issue using electrophysiology and immunohistochemistry in nucleus magnocellularis (NM) of chickens of both sexes, which is known to differ in the expression of Kv1.1 channels depending on characteristic frequency (CF). Just after hearing onset (embryonic day 12-14), Kv1 current gradually increased to a slightly larger extent in neurons with higher CF, causing a tonotopic difference of Kv1 current before hatch. However, after hatch, a much larger increase of Kv1 current occurred, particularly in higher-CF neurons, due to an augmentation of Kv1.1 expression at the plasma membrane. This later change in expression led to the large tonotopic difference of Kv1 current characteristic of mature animals. Attenuation of auditory input by inducing conductive or sensorineural hearing loss around hatch suppressed the differentiation in a level-dependent manner. Moreover, elevation of auditory input during embryonic periods could not reproduce the differentiation, suggesting that the capacity of neurons to drive Kv1.1 expression via auditory input develops in a cell-specific manner, thus underlying the frequency-specific expression of the channel within the nucleus. The results indicated that the tonotopic differentiation of Kv1.1 in NM is partially determined before hatch, but largely driven by afferent input after hatch. Our results highlight the importance of neuronal capacity for sound to drive ion channel expression as well as the level of auditory experience in the frequency tuning of brainstem auditory circuits. SIGNIFICANCE STATEMENT Tuning-frequency-specific expression of ion channels is a prerequisite for auditory system function, but its underlying mechanisms remain unclear. Here, we revealed in avian cochlear nucleus that the expression of Kv1.1 became more dependent on auditory input at a late

  18. Nuclear Structure in Even-Even Nuclei, 24<=Z<=72

    Science.gov (United States)

    Buchhorn, Sarah

    2009-10-01

    Analysis of the spectra of excited nuclei has been used for decades to reveal trends and build models. Power regressions of the form E(J)=a(√J(J+1) )^b fitted to the yrast line of isotopes reveal an average b of ˜0.5ex4 -0.1em/ -0.15em0.25ex3. It should be noted that this is the value predicted for large angular momenta by the Variable Moment of Inertia model [1,2]. A second plot of RJ (RJ=EJ1^+ /E21^+ ) vs. J reveals curves described by power regressions where 0.66(N=90) transition point in several nuclei. A third chart -- an abbreviated energy level diagram including 01^+ ,02^+ ,21^+ ,22^+ , and 41^+ states illustrates the energy increases at magic numbers, along with the near-degenerate two-phonon triplet of 02^+ , 22^+ , and 41^+ - most clearly observed in isotopes of Z=28,34,36,38,44,46, and 48. Lastly, a fourth chart of E31^- against E21^+ shows positive correlation that is well described by equation E(3&-circ;)=A-B2̂E(21^+ ) - not only for Z=54 [3] but also for Z=36,42-52, and 68. Data obtained through ENSDF database. [1] M.A.J.Mariscotti,G.Sharff-Goldhaber and B.Buck, Phys.Rev.178,1864(1969). [2] M.I. Stockmann and V.G.Zelevinsky, Phys.Lett.41B,19(1972). [3] W.F. Mueller et al.,Phys.Rev.C 73, 014316(2006).

  19. Study of shape transition in the neutron-rich Os isotopes

    Directory of Open Access Journals (Sweden)

    John P.R.

    2014-03-01

    Full Text Available The neutron-rich isotopes of tungsten, osmium and platinum have different shapes in their ground states and present also shape transitions phenomena. Spectroscopic information for these nuclei is scarce and often limited to the gamma rays from the decay of isomeric states. For the neutron-rich even-even osmium isotopes 194Os and 198Os, a shape transition between a slightly prolate deformed to an oblate deformed ground state was deduced from the observed level schemes. For the even-even nucleus lying in between, 196Os, no gamma ray transition is known. In order to elucidate the shape transition and to test the nuclear models describing it, this region was investigated through gamma-ray spectroscopy using the AGATA demonstrator and the large acceptance heavy-ion spectrometer PRISMA at LNL, Italy. A two-nucleon transfer from a 198Pt target to a stable 82Se beam was utilized to populate medium-high spin states of 196Os. The analysis method and preliminary results, including the first life-time measurement of isomeric states with AGATA, are presented.

  20. Shape-phase transitions in odd-mass γ -soft nuclei with mass A ≈130

    Science.gov (United States)

    Nomura, K.; Nikšić, T.; Vretenar, D.

    2017-07-01

    Quantum phase transitions between competing equilibrium shapes of nuclei with an odd number of nucleons are explored using a microscopic framework of nuclear energy density functionals and a fermion-boson coupling model. The boson Hamiltonian for the even-even core nucleus, as well as the spherical single-particle energies and occupation probabilities of unpaired nucleons, are completely determined by a constrained self-consistent mean-field calculation for a specific choice of the energy density functional and pairing interaction. Only the strength parameters of the particle-core coupling have to be adjusted to reproduce a few empirical low-energy spectroscopic properties of the corresponding odd-mass system. The model is applied to the odd-A Ba, Xe, La, and Cs isotopes with mass A ≈130 , for which the corresponding even-even Ba and Xe nuclei present a typical case of γ -soft nuclear potential. The theoretical results reproduce the experimental low-energy excitation spectra and electromagnetic properties, and confirm that a phase transition between nearly spherical and γ -soft nuclear shapes occurs also in the odd-A systems.

  1. Multifractal analysis of nucleus-nucleus interactions

    Energy Technology Data Exchange (ETDEWEB)

    Sengupta, K.; Cherry, M.L.; Jones, W.V.; Wefel, J.P. (Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803 (United States)); Dabrowska, A.; Holynski, R.; Jurak, A.; Olszewski, A.; Szarska, M.; Trzupek, A.; Wilczynska, B.; Wilczynski, H.; Wolter, W.; Wosiek, B.; Wozniak, K. (Institute of Nuclear Physics, Kawiory 26 A, 30-055, Krakow (Poland)); Freier, P.S.; Waddington, C.J. (School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455 (United States)); (KLM Collaboration)

    1993-10-01

    We have performed a multifractal ([ital G]-moment) analysis of 14.6--200 GeV/nucleon nucleus-nucleus and 200--800 GeV proton-nucleus interactions from KLM and Fermilab E-90 and E-508 emulsion data, including explicit corrections for the finite statistical sample. The corrected slopes of the [ital G] moments for protons, [sup 16]O, [sup 28]Si, and [sup 32]S nuclei show only slight evidence for departures from random behavior, while the normalized entropies appear to show a more consistent departure from randomness, particularly for protons. Given the size of the uncertainties, the results of the fractal analysis are not consistent either with results of intermittency analyses for nucleus-nucleus collisions or with the nonrandom behavior previously reported for leptonic and hadronic collisions. However, because of the effects of statistical noise, the fractal analysis is not as sensitive as the intermittency analysis for detecting nonrandom fluctuations.

  2. Analytic formula for B(E2) values in even-even nuclei with A>60

    NARCIS (Netherlands)

    Wolf, A.; Scholten, O.; Casten, R. F.

    1991-01-01

    An approximate analytic formula for calculating B(E22+1-->0+1) transition probabilities is proposed. We show that this formula reproduces quite accurately numerical calculations based on the interacting-boson model (IBM), and experimental data for a large number of nuclei from Zn to Pt, and in the

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

    Energy Technology Data Exchange (ETDEWEB)

    Younes, W

    2004-07-15

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

  4. Triaxial quadrupole dynamics and the inner fission barrier of some heavy even-even nuclei

    Science.gov (United States)

    Benrabia, K.; Medjadi, D. E.; Imadalou, M.; Quentin, P.

    2017-09-01

    Background: Inner fission barriers of actinide nuclei have been known for a long time to be unstable with respect to the axial symmetry. On the other hand, taking into account the effect of the relevant adiabatic mass parameter reduces or even may wash out this instability. A proper treatment of the dynamics for both axial and triaxial modes is thus crucial to accurately determine the corresponding fission barriers. This entails in particular an accurate description of pairing correlations. Purpose: We evaluate the potential energies, moments of inertia, and vibrational mass parameters in a two-dimensional relevant deformation space (corresponding to the usual β and γ quadrupole deformation parameters) for four actinide nuclei (236U, 240Pu, 248Cm, and 252Cf). We assess the relevance of our approach to describe the dynamics for a triaxial mode by computing the low energy spectra (exploring thus mainly the equilibrium deformation region). We evaluate the inner fission barrier heights releasing the axial symmetry constraint. Method: Calculations within the Hartree-Fock plus BCS approach are performed using the SkM* Skyrme effective interaction in the particle-hole channel and a seniority force in the particle-particle channel. The intensity of this residual interaction has been fixed to allow a good reproduction of some odd-even mass differences in the actinide region. Adiabatic mass parameters for the rotational and vibrational modes are calculated using the Inglis-Belyaev formula supplemented by a global renormalization factor taking into account the so-called Thouless-Valatin corrections. Spectra are obtained through the diagonalization of the corresponding Bohr collective Hamiltonian. Results: The experimental low energy spectra are qualitatively well reproduced by our calculations for the considered nuclei. Inner fission barrier heights are calculated and compared with available estimates from various experimental data. The reproduction of the data is better for 236U and 240Pu (up to about 300 keV) than for 248Cm and 252Cf (up to about one MeV). Conclusions: While these results are encouraging, they call for, in particular, a better treatment of pairing correlations, especially as far as the particle number conservation is concerned. Besides, these results could provide a basis for the determination of the least action trajectories which would generate better grounds for the evaluation of fission half lives.

  5. Reduced widths of alpha -decay of near-magic even-even nuclei

    CERN Document Server

    Kar Yan, N

    1972-01-01

    Precision on-line investigations on the linear heavy-ion Berkeley accelerator, and on the CERN synchrophasotron were carried out recently on new alpha -emitters. The results obtained are analysed with a view to finding the degree of correspondence, or disagreement, with the authors' own ideas about alpha -decay processes. The discussion is confined to examining even isotopes of polonium, radon, radium and thorium Several theoretical and experimental plots are given of reduced widths of alpha -disintegration for different regions of shell filling and a comparison is made between barrier penetration coefficients, obtained by rigorous methods and with the aid of WKB- approximation, for /sup 212/Po, /sup 208/Po and /sup 212/Po isotopes. (24 refs).

  6. Onuf's nucleus X

    DEFF Research Database (Denmark)

    Schrøder, H D

    1981-01-01

    The first, second and third sacral segments of 59 human spinal cords were examined in order to localize and describe Onuf's nucleus X. The nucleus was found to be situated in the ventral horn of the segments S2 and S3; only in very few spinal cords did it extend into S1. A significant variation...... in the length of the nucleus was observed. Based on the cytoarchitecture the nucleus could be divided in three parts, a cranial, a dorsomedial and a ventrolateral. All parts of the nucleus consisted of chromatin-rich medium-sized neurons, and apparent direct appositions between different cells bodies as well...... as between cell bodies and large dendrites were observed. Characteristic findings in the neuropil surrounding the nucleus were the sparsity of myelinated fibers and the presence of dendritic bundles. The present observations are compared to the descriptions of a morphologically similar nucleus...

  7. Charged-Current Neutrino-Nucleus Scattering off the Even Molybdenum Isotopes

    Directory of Open Access Journals (Sweden)

    E. Ydrefors

    2012-01-01

    Full Text Available Neutrinos from supernovae constitute important probes of both the currently unknown supernova mechanisms and of neutrino properties. Reliable information about the nuclear responses to supernova neutrinos is therefore crucial. In this work, we compute the cross sections for the charged-current neutrino-nucleus scattering off the even-even molybdenum isotopes. The nuclear responses to supernova neutrinos are subsequently calculated by folding the cross sections with a Fermi-Dirac distribution.

  8. ULTRASTRUCTURE OF THE RAT MESENCEPHALIC TRIGEMINAL NUCLEUS

    NARCIS (Netherlands)

    LIEM, RSB; COPRAY, JCVM; VANWILLIGEN, JD

    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

  9. Structural dynamics of the cell nucleus

    Science.gov (United States)

    Wiegert, Simon; Bading, Hilmar

    2011-01-01

    Neuronal morphology plays an essential role in signal processing in the brain. Individual neurons can undergo use-dependent changes in their shape and connectivity, which affects how intracellular processes are regulated and how signals are transferred from one cell to another in a neuronal network. Calcium is one of the most important intracellular second messengers regulating cellular morphologies and functions. In neurons, intracellular calcium levels are controlled by ion channels in the plasma membrane such as NMDA receptors (NMDARs), voltage-gated calcium channels (VGCCs) and certain α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) as well as by calcium exchange pathways between the cytosol and internal calcium stores including the endoplasmic reticulum and mitochondria. Synaptic activity and the subsequent opening of ligand and/or voltage-gated calcium channels can initiate cytosolic calcium transients which propagate towards the cell soma and enter the nucleus via its nuclear pore complexes (NPCs) embedded in the nuclear envelope. We recently described the discovery that in hippocampal neurons the morphology of the nucleus affects the calcium dynamics within the nucleus. Here we propose that nuclear infoldings determine whether a nucleus functions as an integrator or detector of oscillating calcium signals. We outline possible ties between nuclear mophology and transcriptional activity and discuss the importance of extending the approach to whole cell calcium signal modeling in order to understand synapse-to-nucleus communication in healthy and dysfunctional neurons. PMID:21738832

  10. Shape coexistence and shell-model intruder states in the lead region studied by $\\alpha$ -decay

    CERN Multimedia

    2002-01-01

    % IS336 \\\\ \\\\ Low-lying 0$^+$ states in even-even nuclei near closed shells can be a manifestation of the coexistence of different shapes in the same nucleus. Deformed bandstructures built upon these 0$^+$ states, coexisting at low energy with the ground state band, have been observed in several regions of the nuclear chart, including the Z=82 region. Such structures have been found in the neutron-deficient even Pb nuclei and the mixing between intruder and normal states has been studied by the $\\alpha$- decay of $^{194, 196, 198}$Po towards the 0$^+$ excited and ground states in $^{190, 192, 194}$Pb using $\\alpha$-e-t coincidence events. It is expected that shape coexistence will occur in the light Po isotopes as well. Evidence for a deformed band at low excitation energy in $^{196, 198}$Po has been found in in-beam studies and the $\\alpha$-decay of $^{202}$Rn studied at ISOLDE revealed feeding to a 0$^+$~state at 816~keV in $^{198}$Po. \\\\ \\\\It is our intention to investigate the $^{194, 196}$Po nuclei with ...

  11. Study of Relativistic Nucleus - Nucleus Collisions

    CERN Multimedia

    2002-01-01

    The aim of the experiment is to survey the reaction mechanisms involved in the collision of 60~GeV/nucleon and 200~GeV/nucleon light ions ($^{16}$0 and $^{32}$S provided by a new GSI-LBL injector) with different nuclei, to determine the stopping power of nuclear matter and to search for evidence of the formation of quark matter by comparison to hadron-nucleus reactions at the same incident energies. \\\\ The experimental set-up consists of a 2 m Streamer Chamber in the Vertex Magnet used to detect all the charged particles emerging from the interaction as well as the neutral strange particles that decay inside the chamber. The high energy of the forward-going particles are detected by four sets of calorimeters. A highly segmented Photon Position Detector (PPD) backed up by a 240 segment Ring Calorimeter will cover one unit of rapidity around mid-rapidity. An Intermediate Calorimeter will cover the rest of the forward phase space except for the region around beam rapidity, where a Veto Calorimeter will detect be...

  12. A pomeron approach to hadron-nucleus and nucleus-nucleus 'soft' interaction at high energy

    CERN Document Server

    Bondarenko, S; Levin, E; Maor, U

    2001-01-01

    We formulate a generalization of the Glauber formalism for hadron-nucleus and nucleus-nucleus collisions based on the pomeron approach to high-energy interaction. Our treatment is based on two physical assumptions (i.e. two small parameters): (i) that only sufficiently small distances contribute to the pomeron structure; and (ii) the triple-pomeron vertex G sub 3 sub P /g sub P sub N <<1 (where g sub P sub N is the pomeron-nucleon vertex) is small. A systematic method is developed for calculating the total, elastic and diffractive dissociation cross sections as well as the survival probability of large rapidity gap processes and inclusive observables, both for hadron-nucleus and nucleus-nucleus collisions. Our approach suggests saturation of the density of the produced hadrons in nucleus-nucleus collisions, the value of the saturation density turns out to be large.

  13. 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

  14. Nucleus-Nucleus Collision as Superposition of Nucleon-Nucleus Collisions

    Energy Technology Data Exchange (ETDEWEB)

    Orlova, G.I.; Adamovich, M.I.; Aggarwal, M.M.; Alexandrov, Y.A.; Andreeva, N.P.; Badyal, S.K.; Basova, E.S.; Bhalla, K.B.; Bhasin, A.; Bhatia, V.S.; Bradnova, V.; Bubnov, V.I.; Cai, X.; Chasnikov, I.Y.; Chen, G.M.; Chernova, L.P.; Chernyavsky, M.M.; Dhamija, S.; Chenawi, K.El; Felea, D.; Feng, S.Q.; Gaitinov, A.S.; Ganssauge, E.R.; Garpman, S.; Gerassimov, S.G.; Gheata, A.; Gheata, M.; Grote, J.; Gulamov, K.G.; Gupta, S.K.; Gupta, V.K.; Henjes, U.; Jakobsson, B.; Kanygina, E.K.; Karabova, M.; Kharlamov, S.P.; Kovalenko, A.D.; Krasnov, S.A.; Kumar, V.; Larionova, V.G.; Li, Y.X.; Liu, L.S.; Lokanathan, S.; Lord, J.J.; Lukicheva, N.S.; Lu, Y.; Luo, S.B.; Mangotra, L.K.; Manhas, I.; Mittra, I.S.; Musaeva, A.K.; Nasyrov, S.Z.; Navotny, V.S.; Nystrand, J.; Otterlund, I.; Peresadko, N.G.; Qian, W.Y.; Qin, Y.M.; Raniwala, R.; Rao, N.K.; Roeper, M.; Rusakova, V.V.; Saidkhanov, N.; Salmanova, N.A.; Seitimbetov, A.M.; Sethi, R.; Singh, B.; Skelding, D.; Soderstrem, K.; Stenlund, E.; Svechnikova, L.N.; Svensson, T.; Tawfik, A.M.; Tothova, M.; Tretyakova, M.I.; Trofimova, T.P.; Tuleeva, U.I.; Vashisht, Vani; Vokal, S.; Vrlakova, J.; Wang, H.Q.; Wang, X.R.; Weng, Z.Q.; Wilkes, R.J.; Yang, C.B.; Yin, Z.B.; Yu, L.Z.; Zhang, D.H.; Zheng, P.Y.; Zhokhova, S.I.; Zhou, D.C

    1999-03-01

    Angular distributions of charged particles produced in {sup 16}O and {sup 32}S collisions with nuclear track emulsion were studied at momenta 4.5 and 200 A GeV/c. Comparison with the angular distributions of charged particles produced in proton-nucleus collisions at the same momentum allows to draw the conclusion, that the angular distributions in nucleus-nucleus collisions can be seen as superposition of the angular distributions in nucleon-nucleus collisions taken at the same impact parameter b{sub NA}, that is mean impact parameter between the participating projectile nucleons and the center of the target nucleus.

  15. 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.

  16. 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.

  17. Rescattering effects and intermittent exponents in nucleus-nucleus interactions

    Energy Technology Data Exchange (ETDEWEB)

    Pajares, C. (Universidad de Santiago de Compostela (Spain). Dept. de Particulas Elementales)

    1991-04-11

    It is shown that the rescattering in nucleus-nucleus collisions provides a natural branching mechanism which explains the dependence of the intermittent exponents on the energy, projectile and target. The possibility of finding some new coherent phenomena by studying the dependence of the intermittent exponents on the number of collisions is discussed. (orig.).

  18. ANALYTIC FORMULA FOR B(E2) VALUES IN EVEN-EVEN NUCLEI WITH A-GREATER-THAN-60

    NARCIS (Netherlands)

    SCHOLTEN, O; CASTEN, RF

    An approximate analytic formula for calculating B(E2;2(1)+ --> 0(1)+) transition probabilities is proposed. We show that this formula reproduces quite accurately numerical calculations based on the interacting-boson model (IBM), and experimental data for a large number of nuclei from Zn to Pt, and

  19. Evolution of collectivity in a ground-{gamma}-band mixing scheme for even-even transitional nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Lalkovski, S [Faculty of Physics, University of Sofia, 5 James Bourchier, blvd. 1164 Sofia (Bulgaria); Minkov, N [Institute of Nuclear Research and Nuclear Energy, 72 Tzarigrad Road, 1784 Sofia (Bulgaria)

    2005-05-01

    We propose an extended band-mixing formalism capable of describing the structure of the ground- and {gamma}-bands in a wide range of collective spectra beyond the regions of well-deformed nuclei. We apply it to explain the odd-even staggering effect observed in the {gamma}-bands of Mo, Ru and Pd nuclei and to obtain on this basis a consistent interpretation of new experimental data in the neutron rich region. As a result the systematic behaviour of the staggering effect, together with the mutual ground-{gamma}-band disposition, interband mixing and intraband level spacing are explained as the manifestation of respective changes in nuclear collectivity.

  20. The intercalatus nucleus of Staderini.

    Science.gov (United States)

    Cascella, Marco

    2016-01-01

    Rutilio Staderini was one of the leading Italian anatomists of the twentieth century, together with some scientists, such as Giulio Chiarugi, Giovanni Vitali, and others. He was also a member of a new generation of anatomists. They had continued the tradition of the most famous Italian scientists, which started from the Renaissance up until the nineteenth century. Although he carried out important studies of neuroanatomy and comparative anatomy, as well as embryology, his name is rarely remembered by most medical historians. His name is linked to the nucleus he discovered: the Staderini nucleus or intercalated nucleus, a collection of nerve cells in the medulla oblongata located lateral to the hypoglossal nucleus. This article focuses on the biography of the neuroanatomist as well as the nucleus that carries his name and his other research, especially on comparative anatomy and embryology.

  1. Qualitative analysis neurons in the adult human dentate nucleus

    Directory of Open Access Journals (Sweden)

    Marić Dušica

    2012-01-01

    Full Text Available Although many relevant findings regarding to the morphology and cytoarchitectural development of the dentate nucleus have been presented so far, very little qualitative information has been collected on neuronal morphology in the adult human dentate nucleus. The neurons were labelled by Golgi staining from thirty human cerebella, obtained from medico-legal forensic autopsies of adult human bodies and free of significant brain pathology. The human dentate neurons were qualitatively analyzed and these cells were classified into two main classes: the small and the large multipolar neurons. Considering the shape of the cell body, number of the primary dendrites, shape of the dendritic tree and their position within the dentate nucleus, three subclasses of the large multipolar neurons have been recognized. The classification of neurons from the human dentate nucleus has been qualitatively confirmed in fetuses and premature infants. This study represents the first qualitative analysis and classification of the large multipolar neurons in the dentate nucleus of the adult human.

  2. Calculated dynamical evolution of the nucleus of comet Hartley 2

    Science.gov (United States)

    Ksanfomality, Leonid

    2013-04-01

    The nucleus of comet Hartley 2 has a relatively regular dumbbell shape with unequal heads. The narrow part of elongated shape contains a relatively smooth region whose covering material is highly different in its shallow structure compared to other parts of this celestial body. The surface of crudely spherical parts of the nucleus is different from the surface of the "neck", which implies a hypothesis that the shape of the nucleus of Hartley 2 is indicative of destruction of this celestial body occurring in our days. The nucleus rotates around its axis passing through the center of mass, and centrifugal forces arise. This process is hindered by gravitation between parts of the nucleus and gradual slowing of rotation due to body lengthening because of the increase in the moment of inertia (proportional to R2) and due to friction losses in the neck material. We posed the task to determine centrifugal and gravitational forces in the neck (and, respectively, the strains of stretching and compression), the moment of inertia of the body and supply of its rotational energy E, the volume of the nucleus and its average density, and the position of the barycenter and center of rotation. It can be assumed that these forces cause slow but progressive lengthening of the neck which should eventually result in fragmentation of the nucleus. Centrifugal forces can be found as a result of summation of forces produced by parts of the body. According to the calculation model, the total stretching forces in the section passing through the narrowest cut of the neck are 1.21E6 N. The corresponding compression forces in the section passing through the narrow section are 1.04E6 N. The comparison of these values indicates a paradoxical result: stretching strains dominate in the neck, while compressions are dominant in the section passing through the common center of mass. The excess of stretching strains in the neck is 11%. The inference is as follows: the right part of the neck and the

  3. The subthalamic nucleus, Part I

    NARCIS (Netherlands)

    Marani, Enrico; Heida, Tjitske; Lakke, Egbert A.J.F.; Usunoff, Kamen G.

    2008-01-01

    Part I. Development, cytology, topography and connections. This monograph on the subthalamic nucleus accentuates in Part I the gap between experimental animal and human information concerning subthalamic development, cytology, topography and connections. The light and electron microscopical cytology

  4. Heavy flavors in nucleus-nucleus and proton-nucleus collisions

    Directory of Open Access Journals (Sweden)

    Nardi Marzia

    2016-01-01

    Full Text Available A multi-step setup for heavy-flavor studies in high-energy nucleus-nucleus (AA and proton-nucleus (pA collisions is presented. The propagation of the heavy quarks in the medium is described in a framework provided by the relativistic Langevin equation, here solved using weak-coupling transport coefficients. Successively, the heavy quarks hadronize in the medium. We compute the nuclear modification factor and the elliptic flow parameter of the final Dmesons both in AA and in pA collisions and compare our results to experimental data.

  5. Developments in the studies of pear-shaped nuclei and their impact on searches for CP-violation in atoms

    NARCIS (Netherlands)

    Butler, Peter A.; Willmann, Lorenz

    2015-01-01

    The atomic nucleus is a many-body quantum system, and hence its shape is determined by the number of nucleons present in the nucleus and the interactions between them. The long-range correlations between valence nucleons distort the shape from spherical symmetry and the nucleus becomes deformed. In

  6. Elastic and inelastic scattering of neutrons on 238U nucleus

    Directory of Open Access Journals (Sweden)

    Capote R.

    2014-04-01

    Full Text Available Advanced modelling of neutron induced reactions on the 238U nucleus is aimed at improving our knowledge of neutron scattering. Capture and fission channels are well constrained by available experimental data and neutron standard evaluation. A focus of this contribution is on elastic and inelastic scattering cross sections. The employed nuclear reaction model includes – a new rotational-vibrational dispersive optical model potential coupling the low-lying collective bands of vibrational character observed in even-even actinides; – the Engelbrecht-Weidenmüller transformation allowing for inclusion of compound-direct interference effects; – and a multi-humped fission barrier with absorption in the secondary well described within the optical model for fission. Impact of the advanced modelling on elastic and inelastic scattering cross sections including angular distributions and emission spectra is assessed both by comparison with selected microscopic experimental data and integral criticality benchmarks including measured reaction rates (e.g. JEMIMA, FLAPTOP and BIG TEN. Benchmark calculations provided feedback to improve the reaction modelling. Improvement of existing libraries will be discussed.

  7. Fast mixing condensation nucleus counter

    OpenAIRE

    Flagan, Richard C.; Wang, Jian

    2003-01-01

    A fast mixing condensation nucleus counter useful for detecting particles entrained in a sample gas stream is provided. The fast mixing condensation nucleus counter comprises a detector and a mixing condensation device having a mixing chamber adapted to allow gas to flow from an inlet to an outlet, wherein the outlet directs the gas flow to the detector. The mixing chamber has an inlet for introducing vapor-laden gas into the chamber and at least one nozzle for introducing a sample gas having...

  8. Functionalized active-nucleus complex sensor

    Science.gov (United States)

    Pines, Alexander; Wemmer, David E.; Spence, Megan; Rubin, Seth

    2003-11-25

    A functionalized active-nucleus complex sensor that selectively associates with one or more target species, and a method for assaying and screening for one or a plurality of target species utilizing one or a plurality of functionalized active-nucleus complexes with at least two of the functionalized active-nucleus complexes having an attraction affinity to different corresponding target species. The functionalized active-nucleus complex has an active-nucleus and a targeting carrier. The method involves functionalizing an active-nucleus, for each functionalized active-nucleus complex, by incorporating the active-nucleus into a macromolucular or molecular complex that is capable of binding one of the target species and then bringing the macromolecular or molecular complexes into contact with the target species and detecting the occurrence of or change in a nuclear magnetic resonance signal from each of the active-nuclei in each of the functionalized active-nucleus complexes.

  9. The granulocyte nucleus and lamin B receptor: avoiding the ovoid.

    Science.gov (United States)

    Hoffmann, Katrin; Sperling, Karl; Olins, Ada L; Olins, Donald E

    2007-06-01

    The major human blood granulocyte, the neutrophil, is an essential component of the innate immunity system, emigrating from blood vessels and migrating through tight tissue spaces to the site of bacterial or fungal infection where they kill and phagocytose invading microbes. Since the late nineteenth century, it has been recognized that the human neutrophil nucleus is distinctly not ovoid as in other cell types, but possesses a lobulated (segmented) shape. This deformable nucleus enhances rapid migration. Recent studies have demonstrated that lamin B receptor (LBR) is necessary for the non-ovoid shape. LBR is an integral membrane protein of the nuclear envelope. A single dominant mutation in humans leads to neutrophils with hypolobulated nuclei (Pelger-Huet anomaly); homozygosity leads to ovoid granulocyte nuclei. Interestingly, LBR is also an enzyme involved in cholesterol metabolism. Homozygosity for null mutations is frequently lethal and associated with severe skeletal deformities. In addition to the necessity for LBR, formation of the mature granulocyte nucleus also depends upon lamin composition and microtubule integrity. These observations are part of a larger question on the relationships between nuclear shape and cellular function.

  10. 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...

  11. Midpoint Shapes.

    Science.gov (United States)

    Welchman, Rosamond; Urso, Josephine

    2000-01-01

    Emphasizes the importance of children exploring hands-on and minds-on mathematics. Presents a midpoint shape activity for students to explore the midpoint shape of familiar quadrilaterals, such as squares and rectangles. (KHR)

  12. Calcium microdomains in mitochondria and nucleus.

    Science.gov (United States)

    Alonso, María Teresa; Villalobos, Carlos; Chamero, Pablo; Alvarez, Javier; García-Sancho, Javier

    2006-01-01

    Endomembranes modify the progression of the cytosolic Ca(2+) wave and contribute to generate Ca(2+) microdomains, both in the cytosol and inside the own organella. The concentration of Ca(2+) in the cytosol ([Ca(2+)](C)), the mitochondria ([Ca(2+)](M)) and the nucleus ([Ca(2+)](N)) are similar at rest, but may become very different during cell activation. Mitochondria avidly take up Ca(2+) from the high [Ca(2+)](C) microdomains generated during cell activation near Ca(2+) channels of the plasma membrane and/or the endomembranes and prevent propagation of the high Ca(2+) signal to the bulk cytosol. This shaping of [Ca(2+)](C) signaling is essential for independent regulation of compartmentalized cell functions. On the other hand, a high [Ca(2+)](M) signal is generated selectively in the mitochondria close to the active areas, which tunes up respiration to the increased local needs. The progression of the [Ca(2+)](C) signal to the nucleus may be dampened by mitochondria, the nuclear envelope or higher buffering power inside the nucleoplasm. On the other hand, selective [Ca(2+)](N) signals could be generated by direct release of stored Ca(2+) into the nucleoplasm. Ca(2+) release could even be restricted to subnuclear domains. Putative Ca(2+) stores include the nuclear envelope, their invaginations inside the nucleoplasm (nucleoplasmic reticulum) and nuclear microvesicles. Inositol trisphosphate, cyclic ADP-ribose and nicotinic acid adenine dinucleotide phosphate have all been reported to produce release of Ca(2+) into the nucleoplasm, but contribution of these mechanisms under physiological conditions is still uncertain.

  13. The human granulocyte nucleus: Unusual nuclear envelope and heterochromatin composition.

    Science.gov (United States)

    Olins, Ada L; Zwerger, Monika; Herrmann, Harald; Zentgraf, Hanswalter; Simon, Amos J; Monestier, Marc; Olins, Donald E

    2008-05-01

    The human blood granulocyte (neutrophil) is adapted to find and destroy infectious agents. The nucleus of the human neutrophil has a segmented appearance, consisting of a linear or branched array of three or four lobes. Adequate levels of lamin B receptor (LBR) are necessary for differentiation of the lobulated nucleus. The levels of other components of the nuclear envelope may also be important for nuclear shape determination. In the present study, immunostaining and immunoblotting procedures explored the levels of various components of the nuclear envelope and heterochromatin, comparing freshly isolated human neutrophils with granulocytic forms of HL-60 cells, a tissue culture model system. In comparison to granulocytic HL-60 cells, blood neutrophil nuclear envelopes contain low-to-negligible amounts of LBR, lamins A/C, B1 and B2, LAP2beta and emerin. Surprisingly, a "mitotic" chromosome marker, H3(S10)phos, is elevated in neutrophil nuclei, compared to granulocytic HL-60 cells. Furthermore, neutrophil nuclei appear to be more fragile to methanol fixation, than observed with granulocytic HL-60 cells. Thus, the human neutrophil nucleus appears to be highly specialized, possessing a paucity of nuclear envelope-stabilizing proteins. In consequence, the neutrophil nucleus appears to be very malleable, supporting rapid migration through tight tissue spaces.

  14. Nuclear shapes: from earliest ideas to multiple shape coexisting structures

    Science.gov (United States)

    Heyde, K.; Wood, J. L.

    2016-08-01

    The concept of the atomic nucleus being characterized by an intrinsic property such as shape came as a result of high precision hyperfine studies in the field of atomic physics, which indicated a non-spherical nuclear charge distribution. Herein, we describe the various steps taken through ingenious experimentation and bold theoretical suggestions that mapped the way for later work in the early 50s by Aage Bohr, Ben Mottelson and James Rainwater. We lay out a long and winding road that marked, in the period of 50s to 70s, the way shell-model and collective-model concepts were reconciled. A rapid increase in both accelerator and detection methods (70s towards the early 2000s) opened new vistas into nuclear shapes, and their coexistence, in various regions of the nuclear mass table. Next, we outline a possible unified view of nuclear shapes: emphasizing decisive steps taken as well as questions remaining, next to the theoretical efforts that could result in an emerging understanding of nuclear shapes, building on the nucleus considered as a strongly interacting system of nucleons as the microscopic starting point.

  15. Absence of jet quenching in peripheral nucleus-nucleus collisions

    Science.gov (United States)

    Loizides, Constantin; Morsch, Andreas

    2017-10-01

    Medium effects on the production of high-pT particles in nucleus-nucleus (AA) collisions are generally quantified by the nuclear modification factor (RAA), defined to be unity in absence of nuclear effects. Modeling particle production including a nucleon-nucleon impact parameter dependence, we demonstrate that RAA at midrapidity in peripheral AA collisions can be significantly affected by event selection and geometry biases. Even without jet quenching and shadowing, these biases cause an apparent suppression for RAA in peripheral collisions, and are relevant for all types of hard probes and all collision energies. Our studies indicate that calculations of jet quenching in peripheral AA collisions should account for the biases, or else they will overestimate the relevance of parton energy loss. Similarly, expectations of parton energy loss in light-heavy collision systems based on comparison with apparent suppression seen in peripheral RAA should be revised. Our interpretation of the peripheral RAA data would unify observations for lighter collision systems or lower energies where significant values of elliptic flow are observed despite the absence of strong jet quenching.

  16. 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.  

  17. Hadron-nucleus bound states

    CERN Document Server

    Yamazaki, T

    2000-01-01

    A new type of nuclear spectroscopy to study hadron-nucleus bound states is described. The first successful experiment was to search for deeply bound pi sup - states in heavy nuclei using the sup 2 sup 0 sup 8 Pb(d, sup 3 He) reaction at GSI, in which a narrow peak arising from the 2p pi sup - orbital coupled with the neutron-hole states was observed at 135 MeV excitation energy. An improved experiment has just been carried out to separately identify the 1s and 2p pi sup - states. These experiments provide important information on the local potential strength, from which the effective mass of pi sup - is deduced to be 20 MeV. This method will be extended to search for eta and omega bound states as well as for K sup - bound states. The advantage of the bound-state spectroscopy versus invariant mass spectroscopy is emphasized.

  18. Action potentials: to the nucleus and beyond.

    Science.gov (United States)

    Saha, Ramendra N; Dudek, Serena M

    2008-04-01

    The neuronal nucleus is now widely accepted as playing a vital role in maintaining long-term changes in synaptic effectiveness. To act, however, the nucleus must be appropriately relayed with information regarding the latest round of synaptic plasticity. Several constraints of doing so in a neuron pertain to the often significant spatial distance of synapses from the nucleus and the number of synapses required for such a signal to reach functional levels in the nucleus. Largely based on the sensitivity of transcriptional responses to NMDA receptor antagonists, it has been postulated that the signals are physically relayed by biochemical messengers from the synapse to the nucleus. Alternatively, a second, less often considered but equally viable method of signal transduction may be initiated by action potentials generated proximal to the nucleus, wherefrom the signal can be relayed directly by calcium or indirectly by biochemical second messengers. We consider action potential-dependent signaling to the nucleus to have its own computational advantages over the synapse-to-nucleus signal for some functions. This minireview summarizes the logic and experimental support for these two modes of signaling and attempts to validate the action potential model as playing an important role in transcriptional regulation relating specifically to long-term synaptic plasticity.

  19. Dynamic shape.

    Science.gov (United States)

    Koenderink, J J; van Doorn, A J

    1986-01-01

    Many useful notions of partial order and/or similarity and relatedness of different geometrical features of smooth shapes that occur in psychologically valid descriptions of shape have no equivalents in the usual geometrical shape theories. This is especially true where similarities are noted between objects of different connectivity: in almost all of the present theories the topological type generates the primary categorization. It is argued that such relations find a logical place only in shape theories that involve morphogenesis. Any object can be embedded uniquely in a morphogenetic sequence if one takes resolution as the parameter of the sequence. A theory of measurement is presented that allows one to define surfaces and (boundary-) curves on multiple levels of resolution. The embedding is essentially unique and is generated via a partial differential equation that governs the evolution. A canonical projection connects any high resolution specimen to lower resolution versions. The bifurcation set of the projection generates natural part boundaries. Singularities of the evolution are completely characterized as emergence, accretion and versification processes (involving topological change) and singularities by which inflections (inflection points for curves, parabolic curves for surfaces) are generated. The latter singularities involve a single process for the generation of inflections and three other processes by which the existing inflection structure may be changed. Relations with existing theories in vogue in robotics and AI, as well as in psychophysics are discussed.

  20. 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.

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

    CERN Multimedia

    Selyuzhenkov, I; Klochkov, V; Herve, A E; Kowalski, S; Kaptur, E A; Kowalik, K L; Dominik, W M; Matulewicz, T N; Krasnoperov, A; Feofilov, G; Vinogradov, L; Kovalenko, V; Johnson, S R; Mills, G B; Planeta, R J; Rubbia, A; Marton, K; Messerly, B A; Puzovic, J; Bogomilov, M V; Bravar, A; Renfordt, R A E; Deveaux, M; Engel, R R; Grzeszczuk, A; Davis, N; Kuich, M; Lyubushkin, V; Kondratev, V; Kadija, K; Diakonos, F; Slodkowski, M A; Rauch, W H; Pistillo, C; Laszlo, A; Nakadaira, T; Hasegawa, T; Sadovskiy, A; Morozov, S; Petukhov, O; Mathes, H; Roehrich, D; Marcinek, A J; Marino, A D; Grebieszkow, K; 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; Koziel, M E; Rondio, E; Larsen, D T; Czopowicz, T R; Seyboth, P; Turko, L; Guber, F; Marin, V; Busygina, O; Strikhanov, M; Taranenko, A; Cirkovic, M; Roth, M A; Pulawski, S M; Aduszkiewicz, A M; Bunyatov, S; Vechernin, V; Nagai, Y; Anticic, T; Dynowski, K M; Mackowiak-pawlowska, M K; Stefanek, G; Pavin, M; Fodor, Z P; Nishikawa, K; Tada, M; Blondel, A P P; Stroebele, H W; Posiadala, M Z; Kolesnikov, V; Andronov, E; Zimmerman, E D; Antoniou, N; Majka, Z; Di luise, S; 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; Damyanova, A; Gazdzicki, M; Unger, M T; Wilczek, A G; Stepaniak, J M; Seryakov, A; Susa, T; Staszel, P P; 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...

  2. Nucleus accumbens surgery for addiction.

    Science.gov (United States)

    Li, Nan; Wang, Jing; Wang, Xue-lian; Chang, Chong-wang; Ge, Shun-nan; Gao, Li; Wu, He-ming; Zhao, Hai-kang; Geng, Ning; Gao, Guo-dong

    2013-01-01

    Opiate addiction remains intractable in a large percentage of patients, and relapse is the biggest hurdle to recovery because of psychological dependence. Multiple studies identify a central role of the nucleus accumbens (NAc) in addiction; several studies note decreased addictive behavior after interventions in this area. Based on animal experiments, our institute started the clinical trial for the treatment of drug addicts' psychological dependence by making lesions in the bilateral NAc with stereotactic surgery from July 2000. The short-term outcomes were encouraging and triggered rapid application of this treatment in China from 2003 to 2004. However, lack of long-term outcomes and controversy eventually led to halting the surgery for addiction by the Ministry of Health of China in November 2004 and a nationwide survey about it later. Our institute had performed this surgery in 272 patients with severe heroin addiction. The follow-up study showed that the 5-year nonrelapse rate was 58% and the quality of life was significantly improved. Patients had several kinds of side effects, but the incidence rate was relatively low. The patients gradually recovered more than 5 years after the surgery. The side effects did not severely influence an individual's life or work. Nationwide surgery showed that the nonrelapse rate was 50% in the sample of 150 cases, from 1167 patients overall who underwent stereotactic surgery in China. Although sometimes accompanied by neuropsychological adverse events, stereotactic ablation of NAc may effectively treat opiate addiction. Lesion location has a significant impact on treatment efficacy and requires further study. Because ablation is irreversible, the NAc surgery for addiction should be performed with cautiousness, and deep brain stimulation (DBS) is an ideal alternative. Copyright © 2013 Elsevier Inc. All rights reserved.

  3. Staggering behavior of the first excited 2{sup +} states of even-even nuclei in a Sp(4, R) classification scheme

    Energy Technology Data Exchange (ETDEWEB)

    Drenska, S.; Georgieva, A.; Minkov, N. [Bulgarian Academy of Sciences, Inst. for Nuclear Research and Nuclear Energy, Sofia (Bulgaria)

    2002-12-01

    We implement a high order discrete derivative analysis of the lowest nuclear collective excitations in terms of the quantum numbers of an algebraic Sp(4, R) classification scheme. The results reveal a fine systematic behavior of nuclear collectivity in terms of nucleon pairing and high order quartetting correlations. (author)

  4. (γ, 2n)-Reaction cross-section calculations of several even-even lanthanide nuclei using different level density models

    Energy Technology Data Exchange (ETDEWEB)

    Kaplan, A., E-mail: abdullahkaplan@sdu.edu.tr [Süleyman Demirel Univesity, Faculty of Arts and Sciences, Department of Physics (Turkey); Sarpün, İ. H. [Afyon Kocatepe University, Faculty of Arts and Sciences, Department of Physics (Turkey); Aydın, A. [Kırıkkale University, Faculty of Arts and Sciences, Department of Physics (Turkey); Tel, E. [Osmaniye Korkut Ata University, Faculty of Arts and Sciences, Department of Physics (Turkey); Çapalı, V.; Özdoǧan, H. [Süleyman Demirel Univesity, Faculty of Arts and Sciences, Department of Physics (Turkey)

    2015-01-15

    There are several level density models that can be used to predict photo-neutron cross sections. Some of them are Constant Temperature + Fermi Gas Model (CTFGM), Back-Shifted Fermi Gas Model (BSFM), Generalized Superfluid Model (GSM), Hartree-Fock-Bogoliubov microscopic Model (HFBM). In this study, the theoretical photo-neutron cross sections produced by (γ, 2n) reactions for several eveneven lanthanide nuclei such as {sup 140,142}Ce, {sup 142,144,146,148,150}Nd, {sup 144,148,150,152,154}Sm, and {sup 160}Gd have been calculated on the different level density models as mentioned above by using TALYS 1.6 and EMPIRE 3.1 computer codes for incident photon energies up to 30 MeV. The obtained results have been compared with each other and available experimental data existing in the EXFOR database. Generally, at least one level density model cross-section calculations are in agreement with the experimental results for all reactions except {sup 144}Sm(γ, 2n){sup 142}Sm along the incident photon energy, TALYS 1.6 BSFM option for the level density model cross-section calculations can be chosen if the experimental data are not available or are improbable to be produced due to the experimental difficulty.

  5. Large philipsite crystal as ferromanganese nodule nucleus

    Digital Repository Service at National Institute of Oceanography (India)

    Ghosh, A.K.; Mukhopadhyay, R.

    We report here the occurrence of, to date, the largest (21 x 10 x 8 mm) phillipsite crystal forming the nucleus of a diagenetically formed ferromanganese nodule from the Central Indian Ocean Basin (CIOB). Assuming an average rate of ferromanganese...

  6. Testing string dynamics in lepton nucleus reactions

    Energy Technology Data Exchange (ETDEWEB)

    Gyulassy, M.; Pluemer, M.

    1989-10-01

    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.

  7. Advances in hard nucleus cataract surgery

    Directory of Open Access Journals (Sweden)

    Wei Cui

    2013-11-01

    Full Text Available Security and perfect vision and fewer complications are our goals in cataract surgery, and hard-nucleus cataract surgery is always a difficulty one. Many new studies indicate that micro-incision phacoemulsification in treating hard nucleus cataract is obviously effective. This article reviews the evolution process of hard nuclear cataract surgery, the new progress in the research of artificial intraocular lens for microincision, and analyse advantages and disadvantages of various surgical methods.

  8. Improved Cloud Condensation Nucleus Spectrometer

    Science.gov (United States)

    Leu, Ming-Taun

    2010-01-01

    An improved thermal-gradient cloud condensation nucleus spectrometer (CCNS) has been designed to provide several enhancements over prior thermal- gradient counters, including fast response and high-sensitivity detection covering a wide range of supersaturations. CCNSs are used in laboratory research on the relationships among aerosols, supersaturation of air, and the formation of clouds. The operational characteristics of prior counters are such that it takes long times to determine aerosol critical supersaturations. Hence, there is a need for a CCNS capable of rapid scanning through a wide range of supersaturations. The present improved CCNS satisfies this need. The improved thermal-gradient CCNS (see Figure 1) incorporates the following notable features: a) The main chamber is bounded on the top and bottom by parallel thick copper plates, which are joined by a thermally conductive vertical wall on one side and a thermally nonconductive wall on the opposite side. b) To establish a temperature gradient needed to establish a supersaturation gradient, water at two different regulated temperatures is pumped through tubes along the edges of the copper plates at the thermally-nonconductive-wall side. Figure 2 presents an example of temperature and supersaturation gradients for one combination of regulated temperatures at the thermally-nonconductive-wall edges of the copper plates. c) To enable measurement of the temperature gradient, ten thermocouples are cemented to the external surfaces of the copper plates (five on the top plate and five on the bottom plate), spaced at equal intervals along the width axis of the main chamber near the outlet end. d) Pieces of filter paper or cotton felt are cemented onto the interior surfaces of the copper plates and, prior to each experimental run, are saturated with water to establish a supersaturation field inside the main chamber. e) A flow of monodisperse aerosol and a dilution flow of humid air are introduced into the main

  9. Cometary science. On the nucleus structure and activity of comet 67P/Churyumov-Gerasimenko.

    Science.gov (United States)

    Sierks, Holger; Barbieri, Cesare; Lamy, Philippe L; Rodrigo, Rafael; Koschny, Detlef; Rickman, Hans; Keller, Horst Uwe; Agarwal, Jessica; A'Hearn, Michael F; Angrilli, Francesco; Auger, Anne-Therese; Barucci, M Antonella; Bertaux, Jean-Loup; Bertini, Ivano; Besse, Sebastien; Bodewits, Dennis; Capanna, Claire; Cremonese, Gabriele; Da Deppo, Vania; Davidsson, Björn; Debei, Stefano; De Cecco, Mariolino; Ferri, Francesca; Fornasier, Sonia; Fulle, Marco; Gaskell, Robert; Giacomini, Lorenza; Groussin, Olivier; Gutierrez-Marques, Pablo; Gutiérrez, Pedro J; Güttler, Carsten; Hoekzema, Nick; Hviid, Stubbe F; Ip, Wing-Huen; Jorda, Laurent; Knollenberg, Jörg; Kovacs, Gabor; Kramm, J Rainer; Kührt, Ekkehard; Küppers, Michael; La Forgia, Fiorangela; Lara, Luisa M; Lazzarin, Monica; Leyrat, Cédric; Lopez Moreno, Josè J; Magrin, Sara; Marchi, Simone; Marzari, Francesco; Massironi, Matteo; Michalik, Harald; Moissl, Richard; Mottola, Stefano; Naletto, Giampiero; Oklay, Nilda; Pajola, Maurizio; Pertile, Marco; Preusker, Frank; Sabau, Lola; Scholten, Frank; Snodgrass, Colin; Thomas, Nicolas; Tubiana, Cecilia; Vincent, Jean-Baptiste; Wenzel, Klaus-Peter; Zaccariotto, Mirco; Pätzold, Martin

    2015-01-23

    Images from the OSIRIS scientific imaging system onboard Rosetta show that the nucleus of 67P/Churyumov-Gerasimenko consists of two lobes connected by a short neck. The nucleus has a bulk density less than half that of water. Activity at a distance from the Sun of >3 astronomical units is predominantly from the neck, where jets have been seen consistently. The nucleus rotates about the principal axis of momentum. The surface morphology suggests that the removal of larger volumes of material, possibly via explosive release of subsurface pressure or via creation of overhangs by sublimation, may be a major mass loss process. The shape raises the question of whether the two lobes represent a contact binary formed 4.5 billion years ago, or a single body where a gap has evolved via mass loss. Copyright © 2015, American Association for the Advancement of Science.

  10. A-Dependence of $\\pi^0$-Meson Production in Proton-Nucleus and Nucleus-Nucleus Collisions at High Energies

    CERN Document Server

    Tokarev, M V; Dedovich, T G

    2000-01-01

    The A-dependence of pi^0-meson production in proton-nucleus and nucleus-nucleus collisions at a high transverse momentum is studied. The concept of z-scaling reflecting the general features of particle interactions is developed for the description of pi^0-meson production. Experimental data on the cross section obtained at ISR, SpS and Tevatron are usen in the analysis. The A-dependence of scale transformation z to alpha cdot z, psi to alpha^-1 cdot psi is established. An indication of the power law, psi (z) approx z^-beta, at high p_T > 4 GeV/c is found. Based on the properties of z-scaling, the dependence of the cross section of pi^0-mesons produced in pA and AA collisions on transverse momentum over the central rapidity range at RHIC energies is predicted.

  11. Open heavy-flavour production in high energy nucleus-nucleus collisions

    NARCIS (Netherlands)

    Mischke, A.

    2010-01-01

    Heavy quarks (charm and bottom) provide sensitive penetrating probes of hot quark matter produced in high energy nucleus-nucleus collisions. Due to their large mass, heavy quarks are believed to be predominantly produced in the initial state of the collision by gluon fusion processes. The study

  12. 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

  13. Cell Biology of the Caenorhabditis elegans Nucleus.

    Science.gov (United States)

    Cohen-Fix, Orna; Askjaer, Peter

    2017-01-01

    Studies on the Caenorhabditis elegans nucleus have provided fascinating insight to the organization and activities of eukaryotic cells. Being the organelle that holds the genetic blueprint of the cell, the nucleus is critical for basically every aspect of cell biology. The stereotypical development of C. elegans from a one cell-stage embryo to a fertile hermaphrodite with 959 somatic nuclei has allowed the identification of mutants with specific alterations in gene expression programs, nuclear morphology, or nuclear positioning. Moreover, the early C. elegans embryo is an excellent model to dissect the mitotic processes of nuclear disassembly and reformation with high spatiotemporal resolution. We review here several features of the C. elegans nucleus, including its composition, structure, and dynamics. We also discuss the spatial organization of chromatin and regulation of gene expression and how this depends on tight control of nucleocytoplasmic transport. Finally, the extensive connections of the nucleus with the cytoskeleton and their implications during development are described. Most processes of the C. elegans nucleus are evolutionarily conserved, highlighting the relevance of this powerful and versatile model organism to human biology. Copyright © 2017 by the Genetics Society of America.

  14. The Nucleus of Comet 67P/Churyumov-Gerasimenko: Lots of Surprises

    Science.gov (United States)

    Weissman, Paul R.; Rosetta Science Working Team

    2016-10-01

    ESA's Rosetta mission has made many new and unexpected discoveries since its arrival at comet 67P/Churyumov-Gerasimenko in August 2014. The first of these was the unusual shape of the cometary nucleus. Although bilobate nuclei had been seen before, the extreme concavities on 67P were unexpected. Evidence gathered during the mission suggests that two independent bodies came together to form 67P, rather than the nucleus being a single body that was sculpted by sublimation and/or other processes. Although not a surprise, early observations showed that the nucleus rotation period had decreased by ~22 minutes since the previous aphelion passage. A similar rotation period decrease was seen post-perihelion during the encounter. These changes likely arise from asymmetric jetting forces from the irregular nucleus. Initially, Rosetta's instruments found little evidence for water ice on the surface; the presence of surface water ice increased substantially as the nucleus approached perihelion. The nucleus bulk density, 533 ± 6 kg/m3, was measured with Radio Science and OSIRIS imaging of the nucleus volume. This confirmed previous estimates based on indirect methods that the bulk density of cometary nuclei was on the order of 500-600 kg/m3 and on measurement of the density of 9P/Tempel 1's nucleus by Deep Impact. Nucleus topography proved to be highly varied, from smooth dust-covered plains to shallow circular basins, to the very rough terrain where the Philae lander came to rest. Evidence of thermal cracking is everywhere. The discovery of cylindrical pits on the surface, typically 100-200m in diameter with similar depths was a major surprise and has been interpreted as sinkholes. "Goose-bump" terrain consisting of apparently random piles of boulders 2-3 m in diameter was another unexpected discovery. Apparent layering with scales of meters to many tens of meters was seen but there was little or no evidence for impact features. Radar tomography of the interior of the "head

  15. In-beam spectroscopic studies of the 44S nucleus

    Science.gov (United States)

    Cáceres, L.; Sohler, D.; Grévy, S.; Sorlin, O.; Dombrádi, Zs.; Bastin, B.; Achouri, N. L.; Angélique, J. C.; Azaiez, F.; Baiborodin, D.; Borcea, R.; Bourgeois, C.; Buta, A.; Bürger, A.; Chapman, R.; Dalouzy, J. C.; Dlouhy, Z.; Drouard, A.; Elekes, Z.; Franchoo, S.; Gaudefroy, L.; Iacob, S.; Laurent, B.; Lazar, M.; Liang, X.; Liénard, E.; Mrazek, J.; Nalpas, L.; Negoita, F.; Nowacki, F.; Orr, N. A.; Penionzhkevich, Y.; Podolyák, Zs.; Pougheon, F.; Poves, A.; Roussel-Chomaz, P.; Saint-Laurent, M. G.; Stanoiu, M.; Stefan, I.

    2012-02-01

    The structure of the 44S nucleus has been studied at GANIL through the one proton knock-out reaction from a 45Cl secondary beam at 42 A·MeV. The γ rays following the de-excitation of 44S were detected in flight using the 70 BaF2 detectors of the Château de Cristal array. An exhaustive γγ-coincidence analysis allowed an unambiguous construction of the level scheme up to an excitation energy of 3301 keV. The existence of the spherical 22+ state is confirmed and three new γ-ray transitions connecting the prolate deformed 21+ level were observed. Comparison of the experimental results to shell model calculations further supports a prolate and spherical shape coexistence with a large mixing of states built on the ground state band in 44S.

  16. Decoding calcium signaling across the nucleus.

    Science.gov (United States)

    Oliveira, André G; Guimarães, Erika S; Andrade, Lídia M; Menezes, Gustavo B; Fatima Leite, M

    2014-09-01

    Calcium (Ca(2+)) is an important multifaceted second messenger that regulates a wide range of cellular events. A Ca(2+)-signaling toolkit has been shown to exist in the nucleus and to be capable of generating and modulating nucleoplasmic Ca(2+) transients. Within the nucleus, Ca(2+) controls cellular events that are different from those modulated by cytosolic Ca(2+). This review focuses on nuclear Ca(2+) signals and their role in regulating physiological and pathological processes. ©2014 Int. Union Physiol. Sci./Am. Physiol. Soc.

  17. 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...

  18. TWO-PHOTON PHYSICS IN NUCLEUS-NUCLEUS COLLISIONS AT RHIC.

    Energy Technology Data Exchange (ETDEWEB)

    NYSTRAND,J.

    1998-09-10

    Ultra-relativistic heavy-ions carry strong electromagnetic and nuclear fields. Interactions between these fields in peripheral nucleus-nucleus collisions can probe many interesting physics topics. This presentation will focus on coherent two-photon and photonuclear processes at RHIC. The rates for these interactions will be high. The coherent coupling of all the protons in the nucleus enhances the equivalent photon flux by a factor Z{sup 2} up to an energy of {approx} 3 GeV. The plans for studying coherent interactions with the STAR experiment will be discussed. Experimental techniques for separating signal from background will be presented.

  19. Two-photon physics in nucleus-nucleus collisions at RHIC

    Energy Technology Data Exchange (ETDEWEB)

    Nystrand, J.; Klein, S.

    1998-09-01

    Ultra-relativistic heavy-ions carry strong electromagnetic and nuclear fields. Interactions between these fields in peripheral nucleus-nucleus collisions can probe many interesting physics topics. This presentation will focus on coherent two-photon and photonuclear processes at RHIC. The rates for these interactions will be high. The coherent coupling of all the protons in the nucleus enhances the equivalent photon flux by a factor Z{sup 2} up to an energy of {approx} 3 GeV. The plans for studying coherent interactions with the STAR experiment will be discussed. Experimental techniques for separating signal from background will be presented.

  20. Resonances in η-light nucleus systems

    Indian Academy of Sciences (India)

    2Departamento de Fisica, Universidad de los Andes, Bogota, Colombia. E-mail: kanchanp@magnum.barc.ernet.in. Abstract. We locate resonances in η-light nucleus elastic scattering using the time delay method. We solve few-body equations within the finite rank approximation in order to calculate the t-matrices and hence ...

  1. Oral alprazolam acutely increases nucleus accumbens perfusion

    OpenAIRE

    Wolf, Daniel H.; Pinkham, Amy E.; Satterthwaite, Theodore D.; Ruparel, Kosha; Elliott, Mark A.; Valdez, Jeffrey; Smith, Mark A.; Detre, John A.; Gur, Ruben C.; Gur, Raquel E.

    2012-01-01

    Benzodiazepines treat anxiety, but can also produce euphoric effects, contributing to abuse. Using perfusion magnetic resonance imaging, we provide the first direct evidence in humans that alprazolam (Xanax) acutely increases perfusion in the nucleus accumbens, a key reward-processing region linked to addiction.

  2. Resonances in η-light nucleus systems

    Indian Academy of Sciences (India)

    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 ...

  3. The Checkerboard Model of the Nucleus

    Science.gov (United States)

    Lach, Theodore

    2015-04-01

    The Checker Board Model (CBM) of the nucleus and the associated extended standard model predicts that nature has 5 generations of quarks not 3 and that Nucleus is 2 dimensional. The CBM theory began with an insight into the structure of the He nucleus around the year 1989. Details of how this theory evolved which took many years, and is found on my web site (http://checkerboard.dnsalias.net) or in the following references One independent check of this model is that the wavelength of the ``up'' quark orbiting inside the proton at 84.8123% the speed of light (around the ``dn'' quark in the center of the proton) turns out to be exactly one de Broglie wavelength something determined after the mass and speed of the up quark were determined by other means. This theory explains the mass of the proton and neutron and their magnetic moments and this along with the beautiful symmetric 2D structure of the He nucleus led to the evolution of this theory. When this theory was first presented at Argonne in 1996, it was the first time that anyone had predicted the quarks orbited inside the proton at relativistic speeds and it was met with skepticism.

  4. Compound nucleus studies withy reverse kinematics

    Energy Technology Data Exchange (ETDEWEB)

    Moretto, L.G.

    1985-06-01

    Reverse kinematics reactions are used to demonstrate the compound nucleus origin of intermediate mass particles at low energies and the extension of the same mechanism at higher energies. No evidence has appeared in our energy range for liquid-vapor equilibrium or cold fragmentation mechanisms. 11 refs., 12 figs.

  5. Suprachiasmatic Nucleus Interaction with the Arcuate Nucleus; Essential for Organizing Physiological Rhythms

    NARCIS (Netherlands)

    Buijs, Frederik N.; Guzmán-Ruiz, Mara; León-Mercado, Luis; Basualdo, Mari Carmen; Escobar, Carolina; Kalsbeek, Andries; Buijs, Ruud M.

    2017-01-01

    The suprachiasmatic nucleus (SCN) is generally considered the master clock, independently driving all circadian rhythms. We recently demonstrated the SCN receives metabolic and cardiovascular feedback adeptly altering its neuronal activity. In the present study, we show that microcuts effectively

  6. Nonequilibrium distribution functions of nucleons in relativistic nucleus-nucleus collisions

    Directory of Open Access Journals (Sweden)

    D. Anchishkin

    2013-03-01

    Full Text Available The collision smearing of the nucleon momenta about their initial values during relativistic nucleus-nucleus collisions is investigated. To a certain degree, our model belongs to the transport type, and we investigate the evolution of the nucleon system created at a nucleus-nucleus collision. However, we parameterize this development by the number of collisions of every particle during evolution rather than by the time variable. It is assumed that the group of nucleons which leave the system after the same number of collisions can be joined in a particular statistical ensemble. The nucleon nonequilibrium distribution functions are derived which depend on a certain number of collisions of a nucleon before a freeze-out.

  7. The production of strangeness and charmonium in nucleus-nucleus collisions

    CERN Document Server

    Geiss, J

    1998-01-01

    The aim of the present theis is to study the space-time evolution of highly relativistic nucleus-nucleus collisions in a microscopic purely hadronic transport theory. Especially the production of strangeness in nucleus-nucleus collisions over a large energy range from SIS- (E sub l sub a sub b =1-2 A.GeV) up to SPS-energies (E sub l sub a sub b +200 A.GeV) for many different systems are studied, whereby for the elementary production cross sections as conservative assumptions as possible are made. The aim is to obtain an excitation function for the production of strangeness over the whole energy range. Furthermore the production of J/psi particles at SPS energies is studied for different systems, whereby a new absorption mechanism of the c anti c pairs is tested.

  8. The resolved nucleus of Comet Siding Spring (C/2013 A1) in MRO HiRISE images

    Science.gov (United States)

    Farnham, Tony; Kelley, Michael S.; Bodewits, Dennis; Bauer, James M.

    2017-10-01

    Comet Siding Spring (C/2013 A1) passed within 140,000 km of Mars on 19 Oct 2014. The MRO spacecraft, in orbit around Mars, used its HiRISE camera to monitor the comet during the encounter, obtaining the first resolved images of the nucleus of a dynamically new comet.MRO observed Siding Spring from 60 hr before, to 15 hr after close approach, obtaining 122 images in three different color filters. Close approach images, with a spatial scale as small as 138 m/pix, reveal an elongated crescent that changes shape over the course of the sequence, indicating that we are seeing a ~1 km non-spherical body from different viewpoints as the comet rapidly sweeps past. To better constrain the characteristics of the nucleus, we are performing detailed analyses, including modeling of the inner coma to separate its flux contribution from that of the nucleus. In conjunction with the coma removal, we will model the nucleus as a prolate/triaxial ellipsoid and, combined with the known illumination and viewing conditions, will use the changing aspect in the images to constrain the size, shape, orientation, albedo and possibly the phase dependence of the nucleus.In addition to the close approach observations, the images before and after close approach capture the coma structure and brightness. The photometric lightcurve from these images shows variability with an 8.1 hr period, which is presumed to be the rotational modulation of the coma activity. The observed morphology changes as well, promising to provide a measure of the nucleus' spin axis orientation.We will report on the results from our analyses, and provide the first direct measurements of the nucleus of a dynamically new comet.

  9. Strangeness production in antiproton-nucleus annihilation

    Directory of Open Access Journals (Sweden)

    Mosel U.

    2012-12-01

    Full Text Available The results of the microscopic transport calculations of p¯ $ar p$-nucleus interactions within a GiBUU model are presented. The dominating mechanism of hyperon production is the strangeness exchange processes K¯N $ar KN$ → γπ and K¯N $ar KN$ → ΞK. The calculated rapidity spectra of Ξ hyperons are significantly shifted to forward rapidities with respect to the spectra of S = −1 hyperons. We argue that this shift should be a sensitive test for the possible exotic mechanisms of p¯ $ar p$-nucleus annihilation. The production of the double Λ-hypernuclei by Ξ− interaction with a secondary target is calculated.

  10. 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....

  11. Cell Biology of the Plant Nucleus.

    Science.gov (United States)

    Meier, Iris; Richards, Eric J; Evans, David E

    2017-04-28

    The eukaryotic nucleus is enclosed by the nuclear envelope, which is perforated by the nuclear pores, the gateways of macromolecular exchange between the nucleoplasm and cytoplasm. The nucleoplasm is organized in a complex three-dimensional fashion that changes over time and in response to stimuli. Within the cell, the nucleus must be viewed as an organelle (albeit a gigantic one) that is a recipient of cytoplasmic forces and capable of morphological and positional dynamics. The most dramatic reorganization of this organelle occurs during mitosis and meiosis. Although many of these aspects are less well understood for the nuclei of plants than for those of animals or fungi, several recent discoveries have begun to place our understanding of plant nuclei firmly into this broader cell-biological context.

  12. Development of a Mobile Ice Nucleus Counter

    Energy Technology Data Exchange (ETDEWEB)

    Kok, Gregory [Droplet Measurement Technologies, Boulder, CO (United States); Kulkarni, Gourihar [Droplet Measurement Technologies, Boulder, CO (United States)

    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°C, and a single stage system can operate the warm wall at -45C. 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.

  13. Systematics of $\\alpha$--nucleus optical potentials

    OpenAIRE

    Mohr, P; Abele, H.; Atzrott, U.; Staudt, G.; Bieber, R; Grün, K.; Oberhummer, H.; Rauscher, T.; Somorjai, E.

    1994-01-01

    Double--folded optical $\\alpha$--nucleus potentials can be used to calculate elastic scattering cross sections in a wide mass-- and energy region. Because of the systematic behavior of the potential parameters we are able to obtain reliable optical potentials for astrophysically relevant reactions even without scattering data in low--energy region. As example we analyze the capture reaction ${^{144}{\\rm Sm}}(\\alpha,\\gamma){^{148}{\\Gd}}$.

  14. Improved Neuroimaging Atlas of the Dentate Nucleus.

    Science.gov (United States)

    He, Naying; Langley, Jason; Huddleston, Daniel E; Ling, Huawei; Xu, Hongmin; Liu, Chunlei; Yan, Fuhua; Hu, Xiaoping P

    2017-07-01

    The dentate nucleus (DN) of the cerebellum is the major output nucleus of the cerebellum and is rich in iron. Quantitative susceptibility mapping (QSM) provides better iron-sensitive MRI contrast to delineate the boundary of the DN than either T2-weighted images or susceptibility-weighted images. Prior DN atlases used T2-weighted or susceptibility-weighted images to create DN atlases. Here, we employ QSM images to develop an improved dentate nucleus atlas for use in imaging studies. The DN was segmented in QSM images from 38 healthy volunteers. The resulting DN masks were transformed to a common space and averaged to generate the DN atlas. The center of mass of the left and right sides of the QSM-based DN atlas in the Montreal Neurological Institute space was -13.8, -55.8, and -36.4 mm, and 13.8, -55.7, and -36.4 mm, respectively. The maximal probability and mean probability of the DN atlas with the individually segmented DNs in this cohort were 100 and 39.3%, respectively, in contrast to the maximum probability of approximately 75% and the mean probability of 23.4 to 33.7% with earlier DN atlases. Using QSM, which provides superior iron-sensitive MRI contrast for delineating iron-rich structures, an improved atlas for the dentate nucleus has been generated. The atlas can be applied to investigate the role of the DN in both normal cortico-cerebellar physiology and the variety of disease states in which it is implicated.

  15. Critical temperature for shape transitions in excited nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Martin, V. [Analisis Numerico, Facultad de Informatica, Universidad Politecnica de Madrid, E-28660, Madrid (Spain); Egido, J.L.; Robledo, L.M. [Departamento de Fisica Teorica, Universidad Autonoma de Madrid, E-28049, Madrid (Spain)

    2004-04-01

    The behavior of shell effects with temperature is studied within the framework of the finite-temperature Hartree-Fock-Bogoliubov theory with the Gogny force. Thermal shape fluctuations in the quadrupole degree of freedom are taken into account in the frame of the Landau theory. Numerical results for the superfluid-to-normal and deformed-to-spherical phase transitions are presented for the nucleus {sup 164}Er. We find that the critical temperature for the deformed-spherical shape transition is much lowered when the thermal shape fluctuations are considered. (orig.)

  16. 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.

  17. J/$\\psi$ production in proton-nucleus and nucleus-nucleus interactions at the CERN SPS

    CERN Document Server

    Abreu, M C; Alexa, C; Arnaldi, R; Ataian, M R; Baglin, C; Baldit, A; Bedjidian, Marc; Beolè, S; Boldea, V; Bordalo, P; Borges, G; Bussière, A; Capelli, L; Castanier, C; Castor, J I; Chaurand, B; Chevrot, I; Cheynis, B; Chiavassa, E; Cicalò, C; Claudino, T; Comets, M P; Constans, N; Constantinescu, S; Cortese, P; De Falco, A; De Marco, N; Dellacasa, G; Devaux, A; Dita, S; Drapier, O; Ducroux, L; Espagnon, B; Fargeix, J; Force, P; Gallio, M; Gavrilov, Yu K; Gerschel, C; Giubellino, P; Golubeva, M B; Gonin, M; Grigorian, A A; Grossiord, J Y; Guber, F F; Guichard, A; Gulkanian, H R; Hakobyan, R S; Haroutunian, R; Idzik, M; Jouan, D; Karavitcheva, T L; Kluberg, L; Kurepin, A B; Le Bornec, Y; Lourenço, C; Macciotta, P; MacCormick, M; Marzari-Chiesa, A; Masera, M; Masoni, A; Monteno, M; Musso, A; Petiau, P; Piccotti, A; Pizzi, J R; Prado da Silva, W L; Prino, F; Puddu, G; Quintans, C; Ramello, L; Ramos, S; Rato-Mendes, P; Riccati, L; Romana, A; Santos, H; Saturnini, P; Scalas, E; Scomparin, E; Serci, S; Shahoyan, R; Sigaudo, F; Silva, S; Sitta, M; Sonderegger, P; Tarrago, X; Topilskaya, N S; Usai, G L; Vercellin, Ermanno; Villatte, L; Willis, N

    2002-01-01

    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/ psi 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/ psi is anomalously suppressed with respect to the pattern observed in proton-nucleus and light ion reactions. (9 refs).

  18. Measuring the physical properties of the nucleus of comet 8P/Tuttle

    Science.gov (United States)

    Groussin, Olivier; Fernandez, Yanga; Jorda, Laurent; Kelley, Michael; Lamy, Philippe; Toth, Imre; Weaver, Hal

    2007-05-01

    Comet 8P/Tuttle is a returning nearly isotropic comet (NIC), i.e., an 'Oort cloud comet', with an outstanding apparition in cycle 4, passing within 0.25 AU of the Earth. We propose to observe it with MIPS (photometry at 24 and 70 micron) and IRS (spectroscopy in the 5-38 micron range), to measure the physical properties of its nucleus: size, shape, rotation period, thermal inertia and mineralogy. This will provide the most detailed view of a NIC nucleus since the spacecraft flyby of 1P/Halley in 1986. The return of 8P is a rare opportunity that Spitzer should not miss. The results should yield a comprehensive picture of this NIC that can be compared to the detailed data collected on ecliptic comets (ECs) during the past 3 decades. The differences and similarities between NICs and ECs should yield valuable insights into the origin and evolution of comets.

  19. Meson-nucleus potentials and the search for meson-nucleus bound states

    Science.gov (United States)

    Metag, V.; Nanova, M.; Paryev, E. Ya.

    2017-11-01

    Recent experiments studying the meson-nucleus interaction to extract meson-nucleus potentials are reviewed. The real part of the potentials quantifies whether the interaction is attractive or repulsive while the imaginary part describes the meson absorption in nuclei. The review is focused on mesons which are sufficiently long-lived to potentially form meson-nucleus quasi-bound states. The presentation is confined to meson production off nuclei in photon-, pion-, proton-, and light-ion induced reactions and heavy-ion collisions at energies near the production threshold. Tools to extract the potential parameters are presented. In most cases, the real part of the potential is determined by comparing measured meson momentum distributions or excitation functions with collision model or transport model calculations. The imaginary part is extracted from transparency ratio measurements. Results on K+ ,K0 ,K- , η ,η‧ , ω, and ϕ mesons are presented and compared with theoretical predictions. The interaction of K+ and K0 mesons with nuclei is found to be weakly repulsive, while the K- , η ,η‧ , ω and ϕ meson-nucleus potentials are attractive, however, with widely different strengths. Because of meson absorption in the nuclear medium the imaginary parts of the meson-nucleus potentials are all negative, again with a large spread. An outlook on planned experiments in the charm sector is given. In view of the determined potential parameters, the criteria and chances for experimentally observing meson-nucleus quasi-bound states are discussed. The most promising candidates appear to be the η and η‧ mesons.

  20. 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.

  1. Shape memory polymers

    Science.gov (United States)

    Wilson, Thomas S.; Bearinger, Jane P.

    2015-06-09

    New shape memory polymer compositions, methods for synthesizing new shape memory polymers, and apparatus comprising an actuator and a shape memory polymer wherein the shape memory polymer comprises at least a portion of the actuator. A shape memory polymer comprising a polymer composition which physically forms a network structure wherein the polymer composition has shape-memory behavior and can be formed into a permanent primary shape, re-formed into a stable secondary shape, and controllably actuated to recover the permanent primary shape. Polymers have optimal aliphatic network structures due to minimization of dangling chains by using monomers that are symmetrical and that have matching amine and hydroxyl groups providing polymers and polymer foams with clarity, tight (narrow temperature range) single transitions, and high shape recovery and recovery force that are especially useful for implanting in the human body.

  2. Shape memory polymers

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, Thomas S.; Bearinger, Jane P.

    2017-08-29

    New shape memory polymer compositions, methods for synthesizing new shape memory polymers, and apparatus comprising an actuator and a shape memory polymer wherein the shape memory polymer comprises at least a portion of the actuator. A shape memory polymer comprising a polymer composition which physically forms a network structure wherein the polymer composition has shape-memory behavior and can be formed into a permanent primary shape, re-formed into a stable secondary shape, and controllably actuated to recover the permanent primary shape. Polymers have optimal aliphatic network structures due to minimization of dangling chains by using monomers that are symmetrical and that have matching amine and hydroxl groups providing polymers and polymer foams with clarity, tight (narrow temperature range) single transitions, and high shape recovery and recovery force that are especially useful for implanting in the human body.

  3. An exceptionally bright, compact starburst nucleus

    Science.gov (United States)

    Margon, Bruce; Anderson, Scott F.; Mateo, Mario; Fich, Michel; Massey, Philip

    1988-01-01

    Observations are reported of a remarkably bright (V about 13) starburst nucleus, 0833 + 652, which has been detected at radio, infrared, optical, ultraviolet, and X-ray wavelengths. Despite an observed flux at each of these wavelengths which is comparable to that of NGC 7714, often considered the 'prototypical' example of the starburst phenomenon, 0833 + 652 appears to be a previously uncataloged object. Its ease of detectability throughout the electromagnetic spectrum should make it useful for a variety of problems in the study of compact emission-line galaxies.

  4. Lectures on the theory of the nucleus

    CERN Document Server

    Sitenko, Aleksej Grigorevich

    1975-01-01

    Provides an advanced and up-to-date account of the theory of nuclear structure and discusses in considerable detail both the superfluid and collective models of the nucleus, in addition to earlier complementary models and theories. The book also examines other important topics such as the rotational and vibrational spectra of nuclei which have not previously been treated in such depth. To summarize, it covers a large amount of theoretical ground in one volume and attempts to fill a serious gap in the literature. Many problems are included

  5. 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

  6. Patterns of hypoglossal nucleus development in the prenatal period of human ontogenesis: a morphometric study

    Directory of Open Access Journals (Sweden)

    V. O. Tyholaz

    2016-12-01

    Full Text Available Better understanding the origin and differentiation of neurons in the medulla oblongata will promote comprehension of different neural systems functional importance, including the hypoglossal nucleus. There are a few studies addressing histostructure and morphometric parameters of hypoglossal nucleus in human embryos and fetuses in the scientific literature. Aim. To establish the structure, morphometric parameters of the hypoglossal nucleus and the nerve cells that go to form it in the embryos and human fetuses of different gestational age. Materials and Methods. A morphological and histological study of 230 human embryos and fetuses from 6–7 to 39–40 weeks of prenatal development was carried out. Results. In the prenatal development of the hypoglossal nucleus from 17–18 weeks of gestation neuroblasts are changed from spherical to oval shape, during the 20–21 weeks polygonal nerve cells are showing in nucleus composition, and polygonal nerve cells become dominated from the 37 week. The biggest area of the hypoglossal nucleus has been determined in human fetuses at gestational age of 39–40 weeks – 0.82±0.04 mm2. The mean values of the nerve cells area are the largest in the 33–34 weeks gestational–age human fetuses – 301,2±9,3 µm2, and the mean values of the nerve cells nuclei are the largest in the 39–40 weeks gestational–age human fetuses – 101,2±3,2 µm2. Conclusions. The most intensive increase in the area of the hypoglossal nucleus identified in human fetuses at gestational age of 10–11 weeks – by 66.7 %, 12–13 weeks – by 45.4 %, 20–21 weeks – 31.2 %, 22–23 weeks – 36 %, 37–38 weeks – by 45.1 %, 39–40 weeks – by 42.7 % (p<0.01. Intensive increase in the mean neuroblasts area was detected in human fetuses at gestational age of 10–11 weeks – by 40.1 %, 17–18 weeks – 48.4 %, and decrease – in human fetuses at gestational age of 37–38 weeks – by 29.9 % (p<0.01. The most intensive

  7. Structural dynamics of the cell nucleus: basis for morphology modulation of nuclear calcium signaling and gene transcription.

    Science.gov (United States)

    Queisser, Gillian; Wiegert, Simon; Bading, Hilmar

    2011-01-01

    Neuronal morphology plays an essential role in signal processing in the brain. Individual neurons can undergo use-dependent changes in their shape and connectivity, which affects how intracellular processes are regulated and how signals are transferred from one cell to another in a neuronal network. Calcium is one of the most important intracellular second messengers regulating cellular morphologies and functions. In neurons, intracellular calcium levels are controlled by ion channels in the plasma membrane such as NMDA receptors (NMDARs), voltage-gated calcium channels (VGCCs) and certain α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) as well as by calcium exchange pathways between the cytosol and internal calcium stores including the endoplasmic reticulum and mitochondria. Synaptic activity and the subsequent opening of ligand and/or voltage-gated calcium channels can initiate cytosolic calcium transients which propagate towards the cell soma and enter the nucleus via its nuclear pore complexes (NPCs) embedded in the nuclear envelope. We recently described the discovery that in hippocampal neurons the morphology of the nucleus affects the calcium dynamics within the nucleus. Here we propose that nuclear infoldings determine whether a nucleus functions as an integrator or detector of oscillating calcium signals. We outline possible ties between nuclear mophology and transcriptional activity and discuss the importance of extending the approach to whole cell calcium signal modeling in order to understand synapse-to-nucleus communication in healthy and dysfunctional neurons.

  8. Alzheimer's disease detection via automatic 3D caudate nucleus segmentation using coupled dictionary learning with level set formulation.

    Science.gov (United States)

    Al-Shaikhli, Saif Dawood Salman; Yang, Michael Ying; Rosenhahn, Bodo

    2016-12-01

    This paper presents a novel method for Alzheimer's disease classification via an automatic 3D caudate nucleus segmentation. The proposed method consists of segmentation and classification steps. In the segmentation step, we propose a novel level set cost function. The proposed cost function is constrained by a sparse representation of local image features using a dictionary learning method. We present coupled dictionaries: a feature dictionary of a grayscale brain image and a label dictionary of a caudate nucleus label image. Using online dictionary learning, the coupled dictionaries are learned from the training data. The learned coupled dictionaries are embedded into a level set function. In the classification step, a region-based feature dictionary is built. The region-based feature dictionary is learned from shape features of the caudate nucleus in the training data. The classification is based on the measure of the similarity between the sparse representation of region-based shape features of the segmented caudate in the test image and the region-based feature dictionary. The experimental results demonstrate the superiority of our method over the state-of-the-art methods by achieving a high segmentation (91.5%) and classification (92.5%) accuracy. In this paper, we find that the study of the caudate nucleus atrophy gives an advantage over the study of whole brain structure atrophy to detect Alzheimer's disease. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  9. Charged particle production in proton-, deuteron-, oxygen- and sulphur-nucleus collisions at 200 GeV per nucleon

    CERN Document Server

    Alber, T.; Bachler, J.; Bartke, J.; Bialkowska, H.; Bloomer, M.A.; Bock, R.; Braithwaite, W.J.; Brinkmann, D.; Brockmann, R.; Buncic, P.; Chan, P.; Cramer, J.G.; Cramer, P.B.; Derado, I.; Eckardt, V.; Eschke, J.; Favuzzi, C.; Ferenc, D.; Fleischmann, B.; Foka, P.; Freund, P.; Fuchs, M.; Gazdzicki, M.; Gladysz, E.; Grebieszkow, J.; Gunther, J.; Harris, J.W.; Hoffmann, M.; Jacobs, P.; Kabana, S.; Kadija, K.; Keidel, R.; Kowalski, M.; Kuhmichel, A.; Lee, J.Y.; Ljubicic, A, Jr.; Margetis, S.; Mitchell, J.T.; Morse, R.; Nappi, E.; Odyniec, G.; Paic, G.; Panagiotou, A.D.; Petridis, A.; Piper, A.; Posa, F.; Poskanzer, Arthur M.; Puhlhofer, F.; Rauch, W.; Renfordt, R.; Retyk, W.; Rohrich, D.; Roland, G.; Rothard, H.; Runge, K.; Sandoval, A.; Schmitz, N.; Schmoetten, E.; Sendelbach, R.; Seyboth, P.; Seyerlein, J.; Skrzypczak, E.; Spinelli, P.; Stock, R.; Strobele, H.; Teitelbaum, L.; Tonse, S.; Trainor, T.A.; Vasileiadis, G.; Vassiliou, M.; Vesztergombi, G.; Vranic, D.; Wenig, S.; Wosiek, B.; Zhu, X.

    1998-01-01

    The transverse momentum and rapidity distributions of net protons and negatively charged hadrons have been measured for minimum bias proton-nucleus and deuteron-gold interactions, as well as central oxygen-gold and sulphur-nucleus collisions at 200 GeV per nucleon. The rapidity density of net protons at midrapidity in central nucleus-nucleus collisions increases both with target mass for sulphur projectiles and with the projectile mass for a gold target. The shape of the rapidity distributions of net protons forward of midrapidity for d+Au and central S+Au collisions is similar. The average rapidity loss is larger than 2 units of rapidity for reactions with the gold target. The transverse momentum spectra of net protons for all reactions can be described by a thermal distribution with `temperatures' between 145 +- 11 MeV (p+S interactions) and 244 +- 43 MeV (central S+Au collisions). The multiplicity of negatively charged hadrons increases with the mass of the colliding system. The shape of the transverse mom...

  10. A minimal mechanistic model for temporal signal processing in the lateral geniculate nucleus.

    Science.gov (United States)

    Norheim, Eivind S; Wyller, John; Nordlie, Eilen; Einevoll, Gaute T

    2012-06-01

    The receptive fields of cells in the lateral geniculate nucleus (LGN) are shaped by their diverse set of impinging inputs: feedforward synaptic inputs stemming from retina, and feedback inputs stemming from the visual cortex and the thalamic reticular nucleus. To probe the possible roles of these feedforward and feedback inputs in shaping the temporal receptive-field structure of LGN relay cells, we here present and investigate a minimal mechanistic firing-rate model tailored to elucidate their disparate features. The model for LGN relay ON cells includes feedforward excitation and inhibition (via interneurons) from retinal ON cells and excitatory and inhibitory (via thalamic reticular nucleus cells and interneurons) feedback from cortical ON and OFF cells. From a general firing-rate model formulated in terms of Volterra integral equations, we derive a single delay differential equation with absolute delay governing the dynamics of the system. A freely available and easy-to-use GUI-based MATLAB version of this minimal mechanistic LGN circuit model is provided. We particularly investigate the LGN relay-cell impulse response and find through thorough explorations of the model's parameter space that both purely feedforward models and feedback models with feedforward excitation only, can account quantitatively for previously reported experimental results. We find, however, that the purely feedforward model predicts two impulse response measures, the time to first peak and the biphasic index (measuring the relative weight of the rebound phase) to be anticorrelated. In contrast, the models with feedback predict different correlations between these two measures. This suggests an experimental test assessing the relative importance of feedforward and feedback connections in shaping the impulse response of LGN relay cells.

  11. Discriminative Shape Alignment

    DEFF Research Database (Denmark)

    Loog, M.; de Bruijne, M.

    2009-01-01

    The alignment of shape data to a common mean before its subsequent processing is an ubiquitous step within the area shape analysis. Current approaches to shape analysis or, as more specifically considered in this work, shape classification perform the alignment in a fully unsupervised way......, not taking into account that eventually the shapes are to be assigned to two or more different classes. This work introduces a discriminative variation to well-known Procrustes alignment and demonstrates its benefit over this classical method in shape classification tasks. The focus is on two...

  12. Neurochemical organization of the nucleus paramedianus dorsalis in the human

    OpenAIRE

    Baizer, Joan S.; Baker, James F.; Haas, Kristin; Lima, Raquel

    2007-01-01

    We have characterized the neurochemical organization of a small brainstem nucleus in the human brain, the nucleus paramedianus dorsalis (PMD). PMD is located adjacent and medial to the nucleus prepositus hypoglossi (PH) in the dorsal medulla, and is distinguished by the pattern of immunoreactivity of cells and fibers to several markers including calcium-binding proteins, a synthetic enzyme for nitric oxide (neuronal nitric oxide synthase, nNOS) and a nonphosphorylated neurofilament protein (a...

  13. Nucleus and nucleus-cytoskeleton connections in 3D cell migration

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Lingling, E-mail: liulingling2012@163.com; Luo, Qing, E-mail: qing.luo@cqu.edu.cn; Sun, Jinghui, E-mail: sunjhemail@163.com; Song, Guanbin, E-mail: song@cqu.edu.cn

    2016-10-15

    Cell migration plays an important role in many physiological and pathological settings, ranging from embryonic development to cancer metastasis. Currently, accumulating data suggest that cells migrating in three-dimensional (3D) environments show well-defined differences compared to their well-established two-dimensional (2D) counterparts. During 3D migration, the cell body and nucleus must deform to allow cellular passage through the available spaces, and the deformability of the relatively rigid nucleus may constitute a limiting step. Here, we highlight the key evidence regarding the role of the nuclear mechanics in 3D migration, including the molecular components that govern the stiffness of the nucleus and review how the nuclear dynamics are connected to and controlled by cytoskeleton-based migration machinery. Intriguingly, nuclear movement must be coordinated with the cytoskeletal dynamics at the leading and trailing edges, which in turn impact the cytoplasmic dynamics that affect the migration efficiency. Thus, we suggest that alterations in the nuclear structure may facilitate cellular reorganizations that are necessary for efficient migration. - Graphical abstract: Schematic representations of a cell migrating on a 2D substrate and a cell migrating in a 3D extracellular matrix environment. (A) Nucleus-cytoskeleton connections are essential to 3D migration. Mechanical signals are transduced by integrins at the cell surface and channeled to cytoskeletal proteins, which generates prestress. The nucleus-cytoskeleton connections can either act as a stable skeleton to anchor the nuclei or provide active force to move the nuclei. The LINC complex is responsible for the nucleo-cytoskeletal coupling. Nesprins connect the cytoskeletal proteins to the inner nuclear membrane proteins SUN1 and SUN2. The SUN proteins connect to the lamins that form the lamina, which attaches to the chromatin. This physical connectivity transmits the mechanical signals from receptors at

  14. Self-erecting shapes

    Energy Technology Data Exchange (ETDEWEB)

    Reading, Matthew W.

    2017-07-04

    Technologies for making self-erecting structures are described herein. An exemplary self-erecting structure comprises a plurality of shape-memory members that connect two or more hub components. When forces are applied to the self-erecting structure, the shape-memory members can deform, and when the forces are removed the shape-memory members can return to their original pre-deformation shape, allowing the self-erecting structure to return to its own original shape under its own power. A shape of the self-erecting structure depends on a spatial orientation of the hub components, and a relative orientation of the shape-memory members, which in turn depends on an orientation of joining of the shape-memory members with the hub components.

  15. Shaped Recess Flow Control

    Science.gov (United States)

    Shyam, Vikram (Inventor); Poinsatte, Philip (Inventor); Thurman, Douglas (Inventor)

    2017-01-01

    One or more embodiments of techniques or systems for shaped recess flow control are provided herein. A shaped recess or cavity can be formed on a surface associated with fluid flow. The shaped recess can be configured to create or induce fluid effects, temperature effects, or shedding effects that interact with a free stream or other structures. The shaped recess can be formed at an angle to a free stream flow and may be substantially "V" shaped. The shaped recess can be coupled with a cooling channel, for example. The shaped recess can be upstream or downstream from a cooling channel and aligned in a variety of manners. Due to the fluid effects, shedding effects, and temperature effects created by a shaped recess, lift-off or separation of cooling jets of cooling channels can be mitigated, thereby enhancing film cooling effectiveness.

  16. The Hue of Shapes

    Science.gov (United States)

    Albertazzi, Liliana; Da Pos, Osvaldo; Canal, Luisa; Micciolo, Rocco; Malfatti, Michela; Vescovi, Massimo

    2013-01-01

    This article presents an experimental study on the naturally biased association between shape and color. For each basic geometric shape studied, participants were asked to indicate the color perceived as most closely related to it, choosing from the Natural Color System Hue Circle. Results show that the choices of color for each shape were not…

  17. Building with shapes

    CERN Document Server

    Mooney, Carla

    2014-01-01

    There are shapes everywhere you look. You can put shapes together or build with them. What can you build with three circles? In this title, students will explore and understand that certain attributes define what a shape is called. This title will allow students to identify the main purpose of a text, including what the author wants to answer, explain, or describe.

  18. 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)

  19. 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 antimatter nuclei and a benchmark for possible future observations of 4He in cosmic radiation.

  20. A sex difference in the hypothalamic uncinate nucleus: relationship to gender identity.

    Science.gov (United States)

    Garcia-Falgueras, Alicia; Swaab, Dick F

    2008-12-01

    Transsexuality is an individual's unshakable conviction of belonging to the opposite sex, resulting in a request for sex-reassignment surgery. We have shown previously that the bed nucleus of the stria terminalis (BSTc) is female in size and neuron number in male-to-female transsexual people. In the present study we investigated the hypothalamic uncinate nucleus, which is composed of two subnuclei, namely interstitial nucleus of the anterior hypothalamus (INAH) 3 and 4. Post-mortem brain material was used from 42 subjects: 14 control males, 11 control females, 11 male-to-female transsexual people, 1 female-to-male transsexual subject and 5 non-transsexual subjects who were castrated because of prostate cancer. To identify and delineate the nuclei and determine their volume and shape we used three different stainings throughout the nuclei in every 15th section, i.e. thionin, neuropeptide Y and synaptophysin, using an image analysis system. The most pronounced differences were found in the INAH3 subnucleus. Its volume in thionin sections was 1.9 times larger in control males than in females (P 0.117) and females (volume P > 0.245 and number of neurons P > 0.341). There was no difference in INAH3 between pre-and post-menopausal women, either in the volume (P > 0.84) or in the number of neurons (P gender identity.

  1. 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.

  2. Dynamical and statistical aspects in nucleus-nucleus collisions around the Fermi energy

    Energy Technology Data Exchange (ETDEWEB)

    Tamain, B.; Bocage, F.; Bougault, R.; Brou, R. [Caen Univ., 14 (France). Lab. de Physique Corpusculaire; Assenard, M. [Centre National de la Recherche Scientifique, 44 - Nantes (France). Lab. de Physique Subatomique et des Technologies Associees; Auger, G.; Benlliure, J. [Grand Accelerateur National d`Ions Lourds (GANIL), 14 - Caen (France); Bacri, C.O.; Borderie, B. [Paris-11 Univ., 91 - Orsay (France). Inst. de Physique Nucleaire; Bisquer, E. [Lyon-1 Univ., 69 - Villeurbanne (France). Inst. de Physique Nucleaire] [and others

    1997-12-31

    Nucleus-nucleus collisions at low incident energy are mainly governed by statistical dissipative processes, fusion and deep inelastic reactions being the most important ones. Conversely, in the relativistic energy regime, dynamical effects play a dominant role and one should apply a participant-spectator picture in order to understand the data. In between, the intermediate energy region is a transition one in which it is necessary to disentangle dynamics from statistical effects. Moreover, the Fermi energy region corresponds to available energies comparable with nuclear binding energies and one may except to observe phase transition effects. Experiments performed recently with 4{pi} devices have given quite new data and a much better insight into involved mechanisms and hot nuclear matter properties. INDRA data related to reaction mechanisms and multifragmentation are presented. (author) 53 refs.

  3. A versatile dielectron trigger for nucleon-nucleon and nucleus-nucleus collisions

    CERN Document Server

    Schicker, R; Tsertos, H

    1998-01-01

    A novel approach for a versatile first level dielectron trigger is presented. This trigger operates in the low multiplicity environment of nucleon-nucleon reactions as well as in the high multiplicity situation of nucleus-nucleus collisions. For optimal trigger performance, time of flight conditions for the two fastest particles of the event are combined with event multiplicity requirements. The dielectron trigger efficiency is given. The event reduction factor of such a trigger approach is studied for a low, a medium and a high multiplicity environment. The impact parameter dependence of the event reduction is given. The timing properties of the trigger signal are described. The losses due to deadtime are specified. Finally, the first level trigger rate is reported.

  4. Alpha Shapes and Proteins

    DEFF Research Database (Denmark)

    Winter, Pawel; Sterner, Henrik; Sterner, Peter

    2009-01-01

    We provide a unified description of (weighted) alpha shapes, beta shapes and the corresponding simplicialcomplexes. We discuss their applicability to various protein-related problems. We also discuss filtrations of alpha shapes and touch upon related persistence issues.We claim that the full...... potential of alpha-shapes and related geometrical constructs in protein-related problems yet remains to be realized and verified. We suggest parallel algorithms for (weighted) alpha shapes, and we argue that future use of filtrations and kinetic variants for larger proteins will need such implementation....

  5. Transforming shape in design

    DEFF Research Database (Denmark)

    Prats, Miquel; Lim, Sungwoo; Jowers, Iestyn

    2009-01-01

    This paper is concerned with how design shapes are generated and explored by means of sketching. It presents research into the way designers transform shapes from one state to another using sketch representations. An experimental investigation of the sketching processes of designers is presented....... Connections between sketches are defined in terms of shape transformations and described according to shape rules. These rules provide a formal description of the shape exploration process and develop understanding of the mechanics of sketching in design. The paper concludes by discussing the important...

  6. New quasibound states of the compound nucleus in α -particle capture by the nucleus

    Science.gov (United States)

    Maydanyuk, Sergei P.; Zhang, Peng-Ming; Zou, Li-Ping

    2017-07-01

    We generalize the theory of nuclear decay and capture of Gamow that is based on tunneling through the barrier and internal oscillations inside the nucleus. In our formalism an additional factor is obtained, which describes distribution of the wave function of the the α particle inside the nuclear region. We discover new most stable states (called quasibound states) of the compound nucleus (CN) formed during the capture of α particle by the nucleus. With a simple example, we explain why these states cannot appear in traditional calculations of the α capture cross sections based on monotonic penetrabilities of a barrier, but they appear in a complete description of the evolution of the CN. Our result is obtained by a complete description of the CN evolution, which has the advantages of (1) a clear picture of the formation of the CN and its disintegration, (2) a detailed quantum description of the CN, (3) tests of the calculated amplitudes based on quantum mechanics (not realized in other approaches), and (4) high accuracy of calculations (not achieved in other approaches). These peculiarities are shown with the capture reaction of α +44Ca . We predict quasibound energy levels and determine fusion probabilities for this reaction. The difference between our approach and theory of quasistationary states with complex energies applied for the α capture is also discussed. We show (1) that theory does not provide calculations for the cross section of α capture (according to modern models of the α capture), in contrast with our formalism, and (2) these two approaches describe different states of the α capture (for the same α -nucleus potential).

  7. 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…

  8. Lateral geniculate nucleus histopathology in the rat experimental ...

    African Journals Online (AJOL)

    Although trypanosomosis has a well knownaetiology, histopathological studies on brain regions involved in the control of circadian rhythms are scanty. Lateral geniculate nucleus works in conjunction with the suprachiasmatic nucleus, the master circadian rhythm pacemaker, in regulating circadian rhythms. The purpose of ...

  9. Shape-driven 3D segmentation using spherical wavelets.

    Science.gov (United States)

    Nain, Delphine; Haker, Steven; Bobick, Aaron; Tannenbaum, Allen

    2006-01-01

    This paper presents a novel active surface segmentation algorithm using a multiscale shape representation and prior. We define a parametric model of a surface using spherical wavelet functions and learn a prior probability distribution over the wavelet coefficients to model shape variations at different scales and spatial locations in a training set. Based on this representation, we derive a parametric active surface evolution using the multiscale prior coefficients as parameters for our optimization procedure to naturally include the prior in the segmentation framework. Additionally, the optimization method can be applied in a coarse-to-fine manner. We apply our algorithm to the segmentation of brain caudate nucleus, of interest in the study of schizophrenia. Our validation shows our algorithm is computationally efficient and outperforms the Active Shape Model algorithm by capturing finer shape details.

  10. Organization of projections from the principal sensory trigeminal nucleus to the hypoglossal nucleus in the rat: an experimental light and electron microscopic study with axonal tracer techniques.

    Science.gov (United States)

    Aldes, L D; Boone, T B

    1985-01-01

    The organization of projections from the principal sensory trigeminal nucleus (PSN) to the hypoglossal nucleus (XII) in the rat was investigated at the light and electron microscopic level with retrograde and anterograde axonal tracer techniques. Microiontophoretic injection of horseradish peroxidase (HRP) into XII resulted in retrograde labeling of neurons confined to the dorsal one-third of the PSN. Labeled neurons were found bilaterally, although a clear preponderance for ipsilateral distribution was evident. Most labeled neurons were found in the medial one-third and caudal two-thirds of the PSN. Labeled neurons were large (30-50 micron), round-to-pear shaped multipolar cells with dendrites oriented primarily in the mediolateral direction. At the electron microscopic level, HRP reaction product was found throughout the cytoplasm of soma and processes of PSN projection neurons. The ultrastructural characteristics of these cells included a round, centrally placed nucleus and invaginated nuclear envelope, sparse Nissl bodies, numerous free ribosomes, mitochondria, lysosomes and Golgi complexes. Three to four main stem dendrites gradually tapered from the cell body and numerous synaptic terminals impinged upon soma and dendrites of labeled PSN neurons. Microiontophoretic injection of tritiated amino acids or HRP into the dorsal one-third of the PSN resulted in moderately dense terminal labeling in XII bilaterally, although mainly ipsilaterally. Terminal labeling was found diffusely throughout all regions of XII. Fibers descended the brainstem in the dorsolateral reticular formation and entered XII ventrolaterally. At the electron microscopic level, boutons containing HRP reaction product were found to synapse on dendritic processes in XII. Labeled boutons were characterized by clear, spherical vesicles and an asymmetrical postsynaptic density. The significance of these results are discussed in relation to oro-lingual motor behavior.

  11. Dynamic interaction between actin and nesprin2 maintain the cell nucleus in a prestressed state

    Science.gov (United States)

    Kumar, Abhishek; Shivashankar, G. V.

    2016-12-01

    Mechanical coupling between the nucleus and the cytoskeleton is indispensable for direct force transduction from the extra cellular matrix (ECM) to the chromatin. Although this physical coupling has been shown to be crucial for nuclear positioning and its function, the quantification of nuclear-cytoskeleton interaction has been lacking. In this paper, using various quantitative fluorescence spectroscopy techniques, we investigate the nature of this connection. High-resolution 3D imaging shows that nesprin2G forms short linear structures along actin stress fibers (ASFs) in the apical region of the nucleus. Fluorescence recovery after photobleaching (FRAP) revealed that the alignment of nesprin2G becomes heterogeneous when cell shape is engineered from elongated rectangular shape to square using micropatterned substrates. Further, fluorescence cross-correlation spectroscopy (FCCS) revealed that actin interacts transiently with outer nuclear membrane protein nesprin2G with a time scale of 12 ms. In addition, fluorescence resonance energy transfer (FRET) experiments show that the apical ASFs and nesprin2G are in close physical proximity. This interaction is spatially heterogeneous with high FRET along the ASFs. Lastly, we show that the disruption of actin to nuclear connection by over-expression of Dominant Negative Klarsicht, ANC-1, Syne Homology (DNKASH) leads to an increase in nuclear height. These results not only reveal the characteristics of actin-nesprin2G interaction and its significance in regulating nuclear morphology, but also validate the utility of quantitative fluorescence techniques in deciphering physical connections that are essential for mechanotransduction.

  12. Perspectives in shape analysis

    CERN Document Server

    Bruckstein, Alfred; Maragos, Petros; Wuhrer, Stefanie

    2016-01-01

    This book presents recent advances in the field of shape analysis. Written by experts in the fields of continuous-scale shape analysis, discrete shape analysis and sparsity, and numerical computing who hail from different communities, it provides a unique view of the topic from a broad range of perspectives. Over the last decade, it has become increasingly affordable to digitize shape information at high resolution. Yet analyzing and processing this data remains challenging because of the large amount of data involved, and because modern applications such as human-computer interaction require real-time processing. Meeting these challenges requires interdisciplinary approaches that combine concepts from a variety of research areas, including numerical computing, differential geometry, deformable shape modeling, sparse data representation, and machine learning. On the algorithmic side, many shape analysis tasks are modeled using partial differential equations, which can be solved using tools from the field of n...

  13. 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.

  14. Subthalamic nucleus detects unnatural android movement.

    Science.gov (United States)

    Ikeda, Takashi; Hirata, Masayuki; Kasaki, Masashi; Alimardani, Maryam; Matsushita, Kojiro; Yamamoto, Tomoyuki; Nishio, Shuichi; Ishiguro, Hiroshi

    2017-12-19

    An android, i.e., a realistic humanoid robot with human-like capabilities, may induce an uncanny feeling in human observers. The uncanny feeling about an android has two main causes: its appearance and movement. The uncanny feeling about an android increases when its appearance is almost human-like but its movement is not fully natural or comparable to human movement. Even if an android has human-like flexible joints, its slightly jerky movements cause a human observer to detect subtle unnaturalness in them. However, the neural mechanism underlying the detection of unnatural movements remains unclear. We conducted an fMRI experiment to compare the observation of an android and the observation of a human on which the android is modelled, and we found differences in the activation pattern of the brain regions that are responsible for the production of smooth and natural movement. More specifically, we found that the visual observation of the android, compared with that of the human model, caused greater activation in the subthalamic nucleus (STN). When the android's slightly jerky movements are visually observed, the STN detects their subtle unnaturalness. This finding suggests that the detection of unnatural movements is attributed to an error signal resulting from a mismatch between a visual input and an internal model for smooth movement.

  15. Control of nucleus accumbens activity with neurofeedback.

    Science.gov (United States)

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

    2014-08-01

    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 presented as "neurofeedback." In an fMRI-based neurofeedback experiment designed to elicit NAcc activity, we found that subjects could increase their own NAcc activity, and that display of neurofeedback significantly enhanced their ability to do so. Subjects were not as capable of decreasing their NAcc activity, however, and enhanced control did not persist after subsequent removal of neurofeedback. Further analyses suggested that individuals who recruited positive aroused affect were better able to increase NAcc activity in response to neurofeedback, and that NAcc neurofeedback also elicited functionally correlated activity in the medial prefrontal cortex. Together, these findings suggest that humans can modulate their own NAcc activity and that fMRI-based neurofeedback may augment their efforts. The observed association between positive arousal and effective NAcc control further supports an anticipatory affect account of NAcc function. Copyright © 2014 Elsevier Inc. All rights reserved.

  16. Comparing Realistic Subthalamic Nucleus Neuron Models

    Science.gov (United States)

    Njap, Felix; Claussen, Jens C.; Moser, Andreas; Hofmann, Ulrich G.

    2011-06-01

    The mechanism of action of clinically effective electrical high frequency stimulation is still under debate. However, recent evidence points at the specific activation of GABA-ergic ion channels. Using a computational approach, we analyze temporal properties of the spike trains emitted by biologically realistic neurons of the subthalamic nucleus (STN) as a function of GABA-ergic synaptic input conductances. Our contribution is based on a model proposed by Rubin and Terman and exhibits a wide variety of different firing patterns, silent, low spiking, moderate spiking and intense spiking activity. We observed that most of the cells in our network turn to silent mode when we increase the GABAA input conductance above the threshold of 3.75 mS/cm2. On the other hand, insignificant changes in firing activity are observed when the input conductance is low or close to zero. We thus reproduce Rubin's model with vanishing synaptic conductances. To quantitatively compare spike trains from the original model with the modified model at different conductance levels, we apply four different (dis)similarity measures between them. We observe that Mahalanobis distance, Victor-Purpura metric, and Interspike Interval distribution are sensitive to different firing regimes, whereas Mutual Information seems undiscriminative for these functional changes.

  17. Parity Measurements in the 70Ga Nucleus

    Science.gov (United States)

    Venegas Vargas, D. C.; Haring-Kaye, R. A.; Jones, K. D.; Le, K. Q.; Harbin, B. L.; Döring, J.; Abromeit, B.; Dungan, R.; Lubna, R.; Tabor, S. L.; Tai, P.-L.; Tripati, Vandana; Vonmoss, J. M.; Morrow, S. I.

    2017-09-01

    The odd-odd 70Ga nucleus was studied at high spin after being produced at Florida State University using the 62Ni(14C,αpn) fusion-evaporation reaction at a beam energy of 50 MeV. The resulting γ rays were detected in coincidence using an array of Compton-suppressed Ge detectors consisting of three Clover detectors and seven single-crystal detectors. The linear polarizations of eight γ-ray transitions in 70Ga were measured by comparing their scattering yields within a Clover detector in the parallel and perpendicular directions relative to the beam axis, under the requirement that at least one other γ ray in 70Ga was recorded by a single-crystal detector in the array. As a result of these measurements, the parities of six states were confirmed and those of two other states were established for the first time based on a comparison of the experimental polarizations with the predicted ones determined from known spin assignments. The resulting level spectrum of 70Ga shows both similarities and differences with the predictions of previous shell-model calculations. This work was supported by the U.S. National Science Foundation and the Ohio Wesleyan University Summer Science Research Program.

  18. Restoring Segmental Biomechanics Through Nucleus Augmentation: An In Vitro Study.

    Science.gov (United States)

    Pelletier, Matthew H; Cohen, Charles S; Ducheyne, Paul; Walsh, William R

    2016-12-01

    In vitro biomechanical laboratory study. The purpose of this study is to evaluate a mechanical treatment to create a degenerative motion segment and the ability of nucleus augmentation to restore biomechanics. In cases with an intact annulus fibrosus, the replacement or augmentation of the nucleus pulposus alone may provide a less invasive option to restore normal biomechanics and disk height when compared with spinal fusion or total disk replacement. Laboratory testing allows these changes to be fully characterized. However, without preexisting pathology, nucleus augmentation therapies are difficult to evaluate in vitro. The present study evaluated pure moment bending and compressive biomechanics in 3 states (n=6): (1) intact, (2) after creep loading and nucleus disruption to induce degenerative biomechanical changes, and (3) after nucleus augmentation through an injectable polymer (DiscCell). Neutral zone and ROM were increased in all modes of bending after the degenerative treatment. The most sensitive mode of bending was lateral bending, with intact ROM (20.0±2.9 degrees) increased to 22.3±2.6 degrees after degenerative treatment and reduced to 18.4±1.6 degrees after injection of the polymer. All bending ROM and NZ changes induced by the degenerative treatment were reversed by nucleus augmentation. This material was shown to be effective at altering motion segment biomechanics and restoring disk height during time zero tests. This technique may provide a model to examine the time zero performance of a nucleus augmentation device/material.

  19. Multiscale 3-D shape representation and segmentation using spherical wavelets.

    Science.gov (United States)

    Nain, Delphine; Haker, Steven; Bobick, Aaron; Tannenbaum, Allen

    2007-04-01

    This paper presents a novel multiscale shape representation and segmentation algorithm based on the spherical wavelet transform. This work is motivated by the need to compactly and accurately encode variations at multiple scales in the shape representation in order to drive the segmentation and shape analysis of deep brain structures, such as the caudate nucleus or the hippocampus. Our proposed shape representation can be optimized to compactly encode shape variations in a population at the needed scale and spatial locations, enabling the construction of more descriptive, nonglobal, nonuniform shape probability priors to be included in the segmentation and shape analysis framework. In particular, this representation addresses the shortcomings of techniques that learn a global shape prior at a single scale of analysis and cannot represent fine, local variations in a population of shapes in the presence of a limited dataset. Specifically, our technique defines a multiscale parametric model of surfaces belonging to the same population using a compact set of spherical wavelets targeted to that population. We further refine the shape representation by separating into groups wavelet coefficients that describe independent global and/or local biological variations in the population, using spectral graph partitioning. We then learn a prior probability distribution induced over each group to explicitly encode these variations at different scales and spatial locations. Based on this representation, we derive a parametric active surface evolution using the multiscale prior coefficients as parameters for our optimization procedure to naturally include the prior for segmentation. Additionally, the optimization method can be applied in a coarse-to-fine manner. We apply our algorithm to two different brain structures, the caudate nucleus and the hippocampus, of interest in the study of schizophrenia. We show: 1) a reconstruction task of a test set to validate the expressiveness of

  20. Structure Shape Evolution in Lanthanide and Actinide Nuclei

    Directory of Open Access Journals (Sweden)

    Khalaf A. M.

    2013-04-01

    Full Text Available To give the characteristics of the evolution of the collectivity in even-even nuclei, we studied the behavior of the energy ratios R(4 / 2 and R(6 / 4. All chains of lanthanides begins as vibrational with R(4 / 2 near 2.0 and move towards rotational (R(4 / 2 3.33 as neutron number increases. A rabid jump in R(4 / 2 near N = 90 was seen. The plot of R(4 / 2 against Z shows not only the existence of a shape transitions but also the change in curvature in the data for N = 88 and 90, concave to convex. For intermedi- ate structure the slopes in E-GOS ( E over spin plots range between the vibrator and rotor extremes. The abnormal behavior of the two-neutron separation energies of our lanthanide nuclei as a function of neutron number around neutron number 90 is cal- culated. Nonlinear behavior is observed which indicate that shape phase transition is occurred in this region. The calculated reduced B(E2 transition probabilities of the low states of the ground state band in the nuclei 150 Nd / 152 Sm / 154 Gd / 156 Dy are analyzed and compared to the prediction of vibrational U(5 and rotational SU(3 limits of interacting boson model calculations.

  1. 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.

  2. Shape from touch

    NARCIS (Netherlands)

    Kappers, A.M.L.; Bergmann Tiest, W.M.

    2014-01-01

    The shape of objects cannot only be recognized by vision, but also by touch. Vision has the advantage that shapes can be seen at a distance, but touch has the advantage that during exploration many additional object properties become available, such as temperature (Jones, 2009), texture (Bensmaia,

  3. The nucleus retroambiguus control of respiration.

    Science.gov (United States)

    Subramanian, Hari H; Holstege, Gert

    2009-03-25

    The role of the nucleus retroambiguus (NRA) in the context of respiration control has been subject of debate for considerable time. To solve this problem, we chemically (using d, l-homocysteic acid) stimulated the NRA in unanesthetized precollicularly decerebrated cats and studied the respiratory effect via simultaneous measurement of tracheal pressure and electromyograms of diaphragm, internal intercostal (IIC), cricothyroid (CT), and external oblique abdominal (EO) muscles. NRA-stimulation 0-1 mm caudal to the obex resulted in recruitment of IIC muscle and reduction in respiratory frequency. NRA-stimulation 1-3 mm caudal to the obex produced vocalization along with CT activation and slight increase in tracheal pressure, but no change in respiratory frequency. NRA-stimulation 3-5 mm caudal to the obex produced CT muscle activation and an increase in respiratory frequency, but no vocalization. NRA-stimulation 5-8 mm caudal to the obex produced EO muscle activation and reduction in respiratory frequency. A change to the inspiratory effort was never observed, regardless of which NRA part was stimulated. The results demonstrate that NRA does not control eupneic inspiration but consists of topographically separate groups of premotor interneurons each producing detailed motor actions. These motor activities have in common that they require changes to eupneic breathing. Different combination of activation of these premotor neurons determines the final outcome, e.g., vocalization, vomiting, coughing, sneezing, mating posture, or child delivery. Higher brainstem regions such as the midbrain periaqueductal gray (PAG) decides which combination of NRA neurons are excited. In simple terms, the NRA is the piano, the PAG one of the piano players.

  4. Quantitative analysis of the fusion cross sections using different microscopic nucleus-nucleus interactions

    Energy Technology Data Exchange (ETDEWEB)

    Adel, A. [Cairo University, Physics Department, Faculty of Science, Giza (Egypt); Majmaah University, Physics Department, College of Science, Al-Zulfi (Saudi Arabia); Alharbi, T. [Majmaah University, Physics Department, College of Science, Al-Zulfi (Saudi Arabia)

    2017-01-15

    The fusion cross sections for reactions involving medium and heavy nucleus-nucleus systems are investigated near and above the Coulomb barrier using the one-dimensional barrier penetration model. The microscopic nuclear interaction potential is computed by four methods, namely: the double-folding model based on a realistic density-dependent M3Y NN interaction with a finite-range exchange part, the Skyrme energy density functional in the semiclassical extended Thomas-Fermi approximation, the generalized Proximity potential, and the Akyuez-Winther interaction. The comparison between the calculated and the measured values of the fusion excitation functions indicates that the calculations of the DFM give quite satisfactory agreement with the experimental data, being much better than the other methods. New parameterized forms for the fusion barrier heights and positions are presented. Furthermore, the effects of deformation and orientation degrees of freedom on the distribution of the Coulomb barrier characteristics as well as the fusion cross sections are studied for the reactions {sup 16}O + {sup 70}Ge and {sup 28}Si + {sup 100}Mo. The calculated values of the total fusion cross sections are compared with coupled channel calculations using the code CCFULL and compared with the experimental data. Our results reveal that the inclusion of deformations and orientation degrees of freedom improves the comparison with the experimental data. (orig.)

  5. Formation and identification of Centauro and Strangelets in nucleus- nucleus collisions at the LHC

    CERN Document Server

    Angelis, Aris L S; Bogolyubsky, M Yu; Filippov, S N; Gladysz-Dziadus, E; Kharlov, Yu V; Kurepin, A B; Maevskaya, A I; Mavromanolakis, G; Panagiotou, A D; Sadovsky, S A; Stefanski, P; Wlodarczyk, Z

    1999-01-01

    We present a phenomenological model for the formation and decay of a cosmic ray Centauro fireball in the baryon-rich projectile fragmentation rapidity region in nucleus-nucleus interactions. Our model naturally incorporates the $9 possibility of strangelet formation, Strangelets being conjectured to be the "strongly penetrating component" observed in hadron-rich cosmic ray events. Based on this model we have performed Monte-Carlo simulations to study the $9 Centauro and strangelet dynamic and kinematic characteristics in central Pb+Pb collisions at LHC energies, as well as their identification by the detector system CASTOR. CASTOR is being developed for the ALICE heavy ion experiment at $9 the LHC and will probe the very forward pseudorapidity region 5.6

  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. The hidden sides of the nucleus

    CERN Document Server

    Demarthon, F

    2003-01-01

    This dossier treats in a digest way of the recent advances in the study of nuclei: the study of exotic nuclei and its stakes in the understanding of matter and of the Universe; the historical changes of nuclei models through a retrospective of the main scientists who contributed to their elaboration; the questioning of the nuclei stability valley by recent discoveries; the high-technology facilities for the production of exotic nuclei; a new kind of radioactivity: the two-proton decay; the strange shapes of nuclei: pear, banana, saucer; the halo and cluster nuclei and their associated theories. (J.S.)

  8. 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.

  9. Colour, albedo and nucleus size of Halley's comet

    Science.gov (United States)

    Cruikshank, D. P.; Tholen, D. J.; Hartmann, W. K.

    1985-01-01

    Photometry of Halley's comet in the B, J, V, and K broadband filters during a time when the coma was very weak and presumed to contribute negligibly to the broadband photometry is reported. The V-J and J-K colors suggest that the color of the nucleus of Halley's comet is similar to that of the D-type asteroids, which in turn suggests that the surface of the nucleus has an albedo less than 0.1.

  10. The TLC: A Novel Auditory Nucleus of the Mammalian Brain

    OpenAIRE

    Saldaña Fernández, Enrique; Viñuela, Antonio; Marshall, Allen F.; Fitzpatrick, Douglas C.; Aparicio Vaquero, María Auxiliadora

    2007-01-01

    [EN]We have identified a novel nucleus of the mammalian brain and termed it the tectal longitudinal column (TLC). Basic histologic stains, tract-tracing techniques and three-dimensional reconstructions reveal that the rat TLC is a narrow, elongated structure spanning themidbrain tectum longitudinally. This paired nucleus is located close to the midline, immediately dorsal to the periaqueductal gray matter.It occupies what has traditionally been considered the most medial region of the deep su...

  11. The exchangeability of shape

    Directory of Open Access Journals (Sweden)

    Kaba Dramane

    2010-10-01

    Full Text Available Abstract Background Landmark based geometric morphometrics (GM allows the quantitative comparison of organismal shapes. When applied to systematics, it is able to score shape changes which often are undetectable by traditional morphological studies and even by classical morphometric approaches. It has thus become a fast and low cost candidate to identify cryptic species. Due to inherent mathematical properties, shape variables derived from one set of coordinates cannot be compared with shape variables derived from another set. Raw coordinates which produce these shape variables could be used for data exchange, however they contain measurement error. The latter may represent a significant obstacle when the objective is to distinguish very similar species. Results We show here that a single user derived dataset produces much less classification error than a multiple one. The question then becomes how to circumvent the lack of exchangeability of shape variables while preserving a single user dataset. A solution to this question could lead to the creation of a relatively fast and inexpensive systematic tool adapted for the recognition of cryptic species. Conclusions To preserve both exchangeability of shape and a single user derived dataset, our suggestion is to create a free access bank of reference images from which one can produce raw coordinates and use them for comparison with external specimens. Thus, we propose an alternative geometric descriptive system that separates 2-D data gathering and analyzes.

  12. Shape memory polymer foams

    Science.gov (United States)

    Santo, Loredana

    2016-02-01

    Recent advances in shape memory polymer (SMP) foam research are reviewed. The SMPs belong to a new class of smart polymers which can have interesting applications in microelectromechanical systems, actuators and biomedical devices. They can respond to specific external stimulus changing their configuration and then remember the original shape. In the form of foams, the shape memory behaviour can be enhanced because they generally have higher compressibility. Considering also the low weight, and recovery force, the SMP foams are expected to have great potential applications primarily in aerospace. This review highlights the recent progress in characterization, evaluation, and proposed applications of SMP foams mainly for aerospace applications.

  13. Study of high energy densities over extended nuclear volumes via nucleus-nucleus collisions at the SPS

    CERN Multimedia

    2002-01-01

    This experiment examines in detail the characteristics of ultra-relativistic nucleus-nucleus interactions using $^{16}$O beams of 200 GeV/A from the SPS. The experiment combines 4$\\pi$ calorimeter coverage with measurements of inclusive particle spectra, two-particle correlations, low and high-mass lepton pairs and photons. A multiwire active target allows maximum interaction rates with a minimum of secondary interactions. Additional data are taken with an emulsion target.

  14. Shape memory polyurethane foams

    Directory of Open Access Journals (Sweden)

    B. K. Kim

    2012-01-01

    Full Text Available Molded flexible polyurethane (PU foams have been synthesized from polypropylene glycol (PPG with different molecular weights (Mw and functionalities (f, and 2,4/2,6-toluene diisocyanate (TDI-80 with water as blowing agent. It was found that the glassy state properties of the foam mainly depended on the urethane group content while the rubbery state properties on the crosslink density. That is, PPG of low MW and low f (more urethane groups provided superior glass state modulus, strength, density, shape fixity and glass transition temperature (Tg, while that of high Mw and high f (higher crosslink density showed high rubbery modulus and shape recovery. Consequently shape fixity of low Mw PPG decreased from 85 to 72% while shape recovery increased from 52 to 63% as the content of high Mw PPG increased from 0 to 40%.

  15. Reinforced Airfoil Shaped Body

    DEFF Research Database (Denmark)

    2011-01-01

    The present invention relates to an airfoil shaped body with a leading edge and a trailing edge extending along the longitudinal extension of the body and defining a profile chord, the airfoil shaped body comprising an airfoil shaped facing that forms the outer surface of the airfoil shaped body...... and surrounds an internal volume of the body, a distance member that is connected to the facing inside the body and extends from the facing and into the internal volume of the body, and at least one reinforcing member that operates in tension for reinforcing the facing against inward deflections...... and that is connected to the facing inside the internal volume of the body at the same side of the profile chord as the connection of the distance member to the facing and to the distance member at a distance from the facing....

  16. Shaft mode shape demonstration

    Science.gov (United States)

    Grissom, R.

    1985-01-01

    The dynamic response of a rotating machine is directly influenced by its geometric configuration and all aspects of the rotor construction. These determine two significant parameters, mass distribution and stiffness, which yield a spectrum of natural frequencies and mode shapes. The mode shapes can be presented as snapshots of the characteristic amplitude/phase reponse patterns of the shaft, due to the major forcing function of unbalance, at different rotative speeds. To demonstrate the three shaft mode shapes of the rotor rig using the Shaft Mode Demonstrator and oscilloscopes. The synchronous (1X) amplitude and phase of the rotor vibration in the vertical direction from several points along the shaft is displayed on corresponding points of the demonstrator. Unfiltered vibration from vertical and horizontal probe pairs is displayed on the oscilloscopes in orbit format for a dynamic presentation of the mode shape.

  17. Shape memory polyurethane nanocomposites

    Science.gov (United States)

    Cao, Feina

    Shape memory polymers are smart materials which can remember their original shapes. However, the low recovery stress and low mechanical strength limit the commercial applications of shape memory polymers. In this study, nanoclays were introduced to shape memory polyurethanes (SMPU) to augment these properties by enhance the network of SMPU. Several factors which influence the shape recovery stress were evaluated, including the nature of polymer chain by using different monomers, type of clay particles, extent of filler dispersion, clay content and deformation conditions. It was found that only reactive clay particles were well dispersed into polyurethane matrix by the tethering between --CH2CH 2OH functional groups in clay surfactants and polyurethane chains. Two different shape memory polyurethanes (Systems I & II) prepared by bulk polymerization were compared. The shape memory effect of System I was triggered by melting of the soft segment crystals, while that of System II was by glass transition of the soft segments. It was seen that the reactive clay particles dispersed well in both polyurethane matrices and augmented the recovery stress, e.g., 20% increase with 1 wt % nanoclay in System I and 40% increase with 5 wt % nanoclay in System II were observed. In System I, clay particles interfered with soft segment crystallization, and promoted phase mixing between the hard and soft segments, thus affecting the fixity and recovery ratio. Nevertheless, the soft segment crystallinity was still enough and in some cases increased due to stretching to exhibit excellent shape fixity and shape recovery ratio. The higher loading of clay particles accelerated the stress relaxation, resulting in reduction of recovery stress. In System II, no significant effect of clay particles in phase separation was observed, so there was no influence of clay on shape fixity and recovery ratio. The recovery stress increased with reactive nanoclay content. It was also found that the recovery

  18. Rat nucleus accumbens core astrocytes modulate reward and the motivation to self-administer ethanol after abstinence.

    Science.gov (United States)

    Bull, Cecilia; Freitas, Kelen C C; Zou, Shiping; Poland, Ryan S; Syed, Wahab A; Urban, Daniel J; Minter, Sabrina C; Shelton, Keith L; Hauser, Kurt F; Negus, S Stevens; Knapp, Pamela E; Bowers, M Scott

    2014-11-01

    Our understanding of the active role that astrocytes play in modulating neuronal function and behavior is rapidly expanding, but little is known about the role that astrocytes may play in drug-seeking behavior for commonly abused substances. Given that the nucleus accumbens is critically involved in substance abuse and motivation, we sought to determine whether nucleus accumbens astrocytes influence the motivation to self-administer ethanol following abstinence. We found that the packing density of astrocytes that were expressing glial fibrillary acidic protein increased in the nucleus accumbens core (NAcore) during abstinence from EtOH self-administration. No change was observed in the nucleus accumbens shell. This increased NAcore astrocyte density positively correlated with the motivation for ethanol. Astrocytes can communicate with one another and influence neuronal activity through gap-junction hemichannels. Because of this, the effect of blocking gap-junction hemichannels on the motivation for ethanol was examined. The motivation to self-administer ethanol after 3 weeks abstinence was increased following microinjection of gap-junction hemichannel blockers into the NAcore at doses that block both neuronal and astrocytic channels. In contrast, no effect was observed following microinjection of doses that are not thought to block astrocytic channels or following microinjection of either dose into the nucleus accumbens shell. Additionally, the motivation for sucrose after 3 weeks abstinence was unaffected by NAcore gap-junction hemichannel blockers. Next, Designer Receptors Exclusively Activated by Designer Drugs (DREADDs) were selectively expressed in NAcore astrocytes to test the effect of astrocyte stimulation. DREADD activation increased cytosolic calcium in primary astrocytes, facilitated responding for rewarding brain stimulation, and reduced the motivation for ethanol after 3 weeks abstinence. This is the first work to modulate drug-seeking behavior with

  19. Xenopus LAP2β protein knockdown affects location of lamin B and nucleoporins and has effect on assembly of cell nucleus and cell viability.

    Science.gov (United States)

    Dubińska-Magiera, Magda; Chmielewska, Magdalena; Kozioł, Katarzyna; Machowska, Magdalena; Hutchison, Christopher J; Goldberg, Martin W; Rzepecki, Ryszard

    2016-05-01

    Xenopus LAP2β protein is the single isoform expressed in XTC cells. The protein localizes on heterochromatin clusters both at the nuclear envelope and inside a cell nucleus. The majority of XLAP2β fraction neither colocalizes with TPX2 protein during interphase nor can be immunoprecipitated with XLAP2β antibody. Knockdown of the XLAP2β protein expression in XTC cells by synthetic siRNA and plasmid encoded siRNA resulted in nuclear abnormalities including changes in shape of nuclei, abnormal chromatin structure, loss of nuclear envelope, mislocalization of integral membrane proteins of INM such as lamin B2, mislocalization of nucleoporins, and cell death. Based on timing of cell death, we suggest mechanism associated with nucleus reassembly or with entry into mitosis. This confirms that Xenopus LAP2 protein is essential for the maintenance of cell nucleus integrity and the process of its reassembly after mitosis.

  20. Shaping the Global Environment

    Science.gov (United States)

    2002-04-09

    SHAPING THE GLOBAL ENVIRONMENT BY LIEUTENANT COLONEL MICHAEL D. ELLERBE United States Army DISTRIBUTION STATEMENT A: Approved for public release...THE GLOBAL ENVIRONMENT by Lieutenant Colonel Michael D. Ellerbe United States Army Colonel Jef Troxel Project Advisor The views expressed in this...Distribution is unlimited. ii ABSTRACT AUTHOR: Michael D. Ellerbe TITLE: SHAPING THE GLOBAL ENVIRONMENT FORMAT: Strategy Research Project DATE: 09 April

  1. On Characterizing Particle Shape

    Science.gov (United States)

    Ennis, Bryan J.; Rickman, Douglas; Rollins, A. Brent; Ennis, Brandon

    2014-01-01

    It is well known that particle shape affects flow characteristics of granular materials, as well as a variety of other solids processing issues such as compaction, rheology, filtration and other two-phase flow problems. The impact of shape crosses many diverse and commercially important applications, including pharmaceuticals, civil engineering, metallurgy, health, and food processing. Two applications studied here include the dry solids flow of lunar simulants (e.g. JSC-1, NU-LHT-2M, OB-1), and the flow properties of wet concrete, including final compressive strength. A multi-dimensional generalized, engineering method to quantitatively characterize particle shapes has been developed, applicable to both single particle orientation and multi-particle assemblies. The two-dimension, three dimension inversion problem is also treated, and the application of these methods to DEM model particles will be discussed. In the case of lunar simulants, flow properties of six lunar simulants have been measured, and the impact of particle shape on flowability - as characterized by the shape method developed here -- is discussed, especially in the context of three simulants of similar size range. In the context of concrete processing, concrete construction is a major contributor to greenhouse gas production, of which the major contributor is cement binding loading. Any optimization in concrete rheology and packing that can reduce cement loading and improve strength loading can also reduce currently required construction safety factors. The characterization approach here is also demonstrated for the impact of rock aggregate shape on concrete slump rheology and dry compressive strength.

  2. 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

  3. The Dorsomedial Suprachiasmatic Nucleus Times Circadian Expression of Kiss1 and the Luteinizing Hormone Surge

    Science.gov (United States)

    Smarr, Benjamin L.; Morris, Emma

    2012-01-01

    Ovulation in mammals is gated by a master circadian clock in the suprachiasmatic nucleus (SCN). GnRH neurons represent the converging pathway through which the brain triggers ovulation, but precisely how the SCN times GnRH neurons is unknown. We tested the hypothesis that neurons expressing kisspeptin, a neuropeptide coded by the Kiss1 gene and necessary for the activation of GnRH cells during ovulation, represent a relay station for circadian information that times ovulation. We first show that the circadian increase of Kiss1 expression, as well as the activation of GnRH cells, relies on intact ipsilateral neural input from the SCN. Second, by desynchronizing the dorsomedial (dm) and ventrolateral (vl) subregions of the SCN, we show that a clock residing in the dmSCN acts independently of the light-dark cycle, and the vlSCN, to time Kiss1 expression in the anteroventral periventricular nucleus of the hypothalamus and that this rhythm is always in phase with the LH surge. In addition, we show that although the timing of the LH surge is governed by the dmSCN, its amplitude likely depends on the phase coherence between the vlSCN and dmSCN. Our results suggest that whereas dmSCN neuronal oscillators are sufficient to time the LH surge through input to kisspeptin cells in the anteroventral periventricular nucleus of the hypothalamus, the phase coherence among dmSCN, vlSCN, and extra-SCN oscillators is critical for shaping it. They also suggest that female reproductive disorders associated with nocturnal shift work could emerge from the desynchronization between subregional oscillators within the master circadian clock. PMID:22454148

  4. Shapes of interacting RNA complexes

    DEFF Research Database (Denmark)

    Fu, Benjamin Mingming; Reidys, Christian

    2014-01-01

    Shapes of interacting RNA complexes are studied using a filtration via their topological genus. A shape of an RNA complex is obtained by (iteratively) collapsing stacks and eliminating hairpin loops.This shape-projection preserves the topological core of the RNA complex and for fixed topological...... genus there are only finitely many such shapes. Our main result is a new bijection that relates the shapes of RNA complexes with shapes of RNA structures. This allows to compute the shape polynomial of RNA complexes via the shape polynomial of RNA structures. We furthermore present a linear time uniform...... sampling algorithm for shapes of RNA complexes of fixed topological genus....

  5. 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

  6. Heterogeneous calretinin expression in the avian cochlear nucleus angularis.

    Science.gov (United States)

    Bloom, S; Williams, A; MacLeod, K M

    2014-08-01

    Multiple calcium-binding proteins (CaBPs) are expressed at high levels and in complementary patterns in the auditory pathways of birds, mammals, and other vertebrates, but whether specific members of the CaBP family can be used to identify neuronal subpopulations is unclear. We used double immunofluorescence labeling of calretinin (CR) in combination with neuronal markers to investigate the distribution of CR-expressing neurons in brainstem sections of the cochlear nucleus in the chicken (Gallus gallus domesticus). While CR was homogeneously expressed in cochlear nucleus magnocellularis, CR expression was highly heterogeneous in cochlear nucleus angularis (NA), a nucleus with diverse cell types analogous in function to neurons in the mammalian ventral cochlear nucleus. To quantify the distribution of CR in the total NA cell population, we used antibodies against neuronal nuclear protein (NeuN), a postmitotic neuron-specific nuclear marker. In NA neurons, NeuN label was variably localized to the cell nucleus and the cytoplasm, and the intensity of NeuN immunoreactivity was inversely correlated with the intensity of CR immunoreactivity. The percentage of CR + neurons in NA increased from 31 % in embryonic (E)17/18 chicks, to 44 % around hatching (E21), to 51 % in postnatal day (P) 8 chicks. By P8, the distribution of CR + neurons was uniform, both rostrocaudal and in the tonotopic (dorsoventral) axis. Immunoreactivity for the voltage-gated potassium ion channel Kv1.1, used as a marker for physiological type, showed broad and heterogeneous postsynaptic expression in NA, but did not correlate with CR expression. These results suggest that CR may define a subpopulation of neurons within nucleus angularis.

  7. A helical structural nucleus is the primary elongating unit of insulin amyloid fibrils.

    Directory of Open Access Journals (Sweden)

    Bente Vestergaard

    2007-05-01

    Full Text Available Although amyloid fibrillation is generally believed to be a nucleation-dependent process, the nuclei are largely structurally uncharacterized. This is in part due to the inherent experimental challenge associated with structural descriptions of individual components in a dynamic multi-component equilibrium. There are indications that oligomeric aggregated precursors of fibrillation, and not mature fibrils, are the main cause of cytotoxicity in amyloid disease. This further emphasizes the importance of characterizing early fibrillation events. Here we present a kinetic x-ray solution scattering study of insulin fibrillation, revealing three major components: insulin monomers, mature fibrils, and an oligomeric species. Low-resolution three-dimensional structures are determined for the fibril repeating unit and for the oligomer, the latter being a helical unit composed of five to six insulin monomers. This helical oligomer is likely to be a structural nucleus, which accumulates above the supercritical concentration used in our experiments. The growth rate of the fibrils is proportional to the amount of the helical oligomer present in solution, suggesting that these oligomers elongate the fibrils. Hence, the structural nucleus and elongating unit in insulin amyloid fibrillation may be the same structural component above supercritical concentrations. A novel elongation pathway of insulin amyloid fibrils is proposed, based on the shape and size of the fibrillation precursor. The distinct helical oligomer described in this study defines a conceptually new basis of structure-based drug design against amyloid diseases.

  8. Three-dimensional positioning and structure of chromosomes in a human prophase nucleus

    Science.gov (United States)

    Chen, Bo; Yusuf, Mohammed; Hashimoto, Teruo; Estandarte, Ana Katrina; Thompson, George; Robinson, Ian

    2017-01-01

    The human genetic material is packaged into 46 chromosomes. The structure of chromosomes is known at the lowest level, where the DNA chain is wrapped around a core of eight histone proteins to form nucleosomes. Around a million of these nucleosomes, each about 11 nm in diameter and 6 nm in thickness, are wrapped up into the complex organelle of the chromosome, whose structure is mostly known at the level of visible light microscopy to form a characteristic cross shape in metaphase. However, the higher-order structure of human chromosomes, between a few tens and hundreds of nanometers, has not been well understood. We show a three-dimensional (3D) image of a human prophase nucleus obtained by serial block-face scanning electron microscopy, with 36 of the complete set of 46 chromosomes captured within it. The acquired image allows us to extract quantitative 3D structural information about the nucleus and the preserved, intact individual chromosomes within it, including their positioning and full spatial morphology at a resolution of around 50 nm in three dimensions. The chromosome positions were found, at least partially, to follow the pattern of chromosome territories previously observed only in interphase. The 3D conformation shows parallel, planar alignment of the chromatids, whose occupied volumes are almost fully accounted for by the DNA and known chromosomal proteins. We also propose a potential new method of identifying human chromosomes in three dimensions, on the basis of the measurements of their 3D morphology. PMID:28776025

  9. Sperm dimorphism in terms of nuclear shape and microtubule accumulation in Cyrtanthus mackenii.

    Science.gov (United States)

    Hirano, Tomonari; Hoshino, Yoichiro

    2010-06-01

    Pollen tubes of Cyrtanthus mackenii, a species with bicellular pollen, were cultured in vitro to investigate nuclear phase changes during generative cell division and male germ unit (MGU) formation, using flow cytometric analysis. Results revealed that sperm cells were formed after 12 h of culture. During sperm maturation, the nuclei of sperm cells were not associated with the vegetative nucleus (unassociated sperm cells; Sua) and became longer than those of sperm cells associated with the vegetative nucleus (Svn). These findings indicate that the pair of sperm cells in the C. mackenii MGU is dimorphic in terms of nuclear shape. Dimorphism coincides with anti-alpha-tubulin antibody immunofluorescence, which was higher in the Sua than in Svn. Following treatment with oryzalin, triggering microtubule depolymerization, differences between nuclear shapes in the two sperm nuclei disappeared, suggesting that microtubule accumulation between sperm cells in the MGU correlates with differences in the nuclear shape.

  10. The Dynamics of Shape

    CERN Document Server

    Gomes, Henrique

    2011-01-01

    This thesis consists of two parts, connected by one central theme: the dynamics of the "shape of space". The first part of the thesis concerns the construction of a theory of gravity dynamically equivalent to general relativity (GR) in 3+1 form (ADM). What is special about this theory is that it does not possess foliation invariance, as does ADM. It replaces that "symmetry" by another: local conformal invariance. In so doing it more accurately reflects a theory of the "shape of space", giving us reason to call it \\emph{shape dynamics} (SD). In the first part we will try to present some of the highlights of results so far, and indicate what we can and cannot do with shape dynamics. Because this is a young, rapidly moving field, we have necessarily left out some interesting new results which are not yet in print and were developed alongside the writing of the thesis. The second part of the thesis will develop a gauge theory for "shape of space"--theories. To be more precise, if one admits that the physically re...

  11. Classical cadherins control nucleus and centrosome position and cell polarity.

    Science.gov (United States)

    Dupin, Isabelle; Camand, Emeline; Etienne-Manneville, Sandrine

    2009-06-01

    Control of cell polarity is crucial during tissue morphogenesis and renewal, and depends on spatial cues provided by the extracellular environment. Using micropatterned substrates to impose reproducible cell-cell interactions, we show that in the absence of other polarizing cues, cell-cell contacts are the main regulator of nucleus and centrosome positioning, and intracellular polarized organization. In a variety of cell types, including astrocytes, epithelial cells, and endothelial cells, calcium-dependent cadherin-mediated cell-cell interactions induce nucleus and centrosome off-centering toward cell-cell contacts, and promote orientation of the nucleus-centrosome axis toward free cell edges. Nucleus and centrosome off-centering is controlled by N-cadherin through the regulation of cell interactions with the extracellular matrix, whereas the orientation of the nucleus-centrosome axis is determined by the geometry of N-cadherin-mediated contacts. Our results demonstrate that in addition to the specific function of E-cadherin in regulating baso-apical epithelial polarity, classical cadherins control cell polarization in otherwise nonpolarized cells.

  12. SHAPE selection (SHAPES) enrich for RNA structure signal in SHAPE sequencing-based probing data

    DEFF Research Database (Denmark)

    Poulsen, Line Dahl; Kielpinski, Lukasz Jan; Salama, Sofie R

    2015-01-01

    transcriptase. Here, we introduce a SHAPE Selection (SHAPES) reagent, N-propanone isatoic anhydride (NPIA), which retains the ability of SHAPE reagents to accurately probe RNA structure, but also allows covalent coupling between the SHAPES reagent and a biotin molecule. We demonstrate that SHAPES...

  13. Cochlear nucleus whole mount explants promote the differentiation of neuronal stem cells from the cochlear nucleus in co-culture experiments.

    Science.gov (United States)

    Rak, Kristen; Völker, Johannes; Jürgens, Lukas; Völker, Christine; Frenz, Silke; Scherzad, Agmal; Schendzielorz, Philipp; Jablonka, Sibylle; Mlynski, Robert; Radeloff, Andreas; Hagen, Rudolf

    2015-08-07

    The cochlear nucleus is the first brainstem nucleus to receive sensory input from the cochlea. Depriving this nucleus of auditory input leads to cellular and molecular disorganization which may potentially be counteracted by the activation or application of stem cells. Neuronal stem cells (NSCs) have recently been identified in the neonatal cochlear nucleus and a persistent neurogenic niche was demonstrated in this brainstem nucleus until adulthood. The present work investigates whether the neurogenic environment of the cochlear nucleus can promote the survival of engrafted NSCs and whether cochlear nucleus-derived NSCs can differentiate into neurons and glia in brain tissue. Therefore, cochlear nucleus whole-mount explants were co-cultured with NSCs extracted from either the cochlear nucleus or the hippocampus and compared to a second environment using whole-mount explants from the hippocampus. Factors that are known to induce neuronal differentiation were also investigated in these NSC-explant experiments. NSCs derived from the cochlear nucleus engrafted in the brain tissue and differentiated into all cells of the neuronal lineage. Hippocampal NSCs also immigrated in cochlear nucleus explants and differentiated into neurons, astrocytes and oligodendrocytes. Laminin expression was up-regulated in the cochlear nucleus whole-mounts and regulated the in vitro differentiation of NSCs from the cochlear nucleus. These experiments confirm a neurogenic environment in the cochlear nucleus and the capacity of cochlear nucleus-derived NSCs to differentiate into neurons and glia. Consequently, the presented results provide a first step for the possible application of stem cells to repair the disorganization of the cochlear nucleus, which occurs after hearing loss. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Developmental Profile of Ion Channel Specializations in the Avian Nucleus Magnocellularis

    Directory of Open Access Journals (Sweden)

    Hui eHong

    2016-03-01

    Full Text Available Ultrafast and temporally precise action potentials (APs are biophysical specializations of auditory brainstem neurons; properties necessary for encoding sound localization and communication cues. Fundamental to these specializations are voltage dependent potassium (KV and sodium (NaV ion channels. Here we characterized the functional development of these ion channels and quantified how they shape AP properties in the avian cochlear nucleus magnocellularis (NM. We report that late developing NM neurons (embryonic [E] days 19-21 generate fast APs that reliably phase lock to sinusoidal inputs at 75 Hz. In contrast, early developing neurons (E19 contained NaV channels that inactivate at more negative voltages, suggesting alterations in NaV channel subtypes. Taken together, our results indicate that the refinement of passive and active ion channel properties operate differentially in order to develop fast and reliable APs in the avian NM.

  15. Is there a medial nucleus of the trapezoid body in humans?

    DEFF Research Database (Denmark)

    Richter, Erik; Norris, B E; Fullerton, B C

    1983-01-01

    The medial nucleus of the trapezoid body (MNTB) appears to be a prominent auditory structure in many mammals. However, the presence of an MNTB in the human brain has not been clearly established. One of the most characteristic features of the cat MNTB is the presence of large somatic endings...... with multiple synaptic sites, the calyces of Held. We examined adult human brains at both light and electron microscopic levels and found neurons with unusually large endings in a location that is similar to that for the MNTB in other animals. Moreover, the sizes and shapes of some cells in this area...... are similar to the principal cells of the cat MNTB. These observations support the idea that humans have cells that resemble MNTB neurons in other species. It has been suggested that the cat MNTB may be involved in the generation of wave 3 of its brainstem auditory evoked potentials, so the presence...

  16. Localization of photoperiod responsive circadian oscillators in the mouse suprachiasmatic nucleus.

    Science.gov (United States)

    Yoshikawa, Tomoko; Inagaki, Natsuko F; Takagi, Seiji; Kuroda, Shigeru; Yamasaki, Miwako; Watanabe, Masahiko; Honma, Sato; Honma, Ken-Ichi

    2017-08-15

    The circadian pacemaker in the suprachiasmatic nucleus (SCN) yields photoperiodic response to transfer seasonal information to physiology and behavior. To identify the precise location involved in photoperiodic response in the SCN, we analyzed circadian Period1 and PERIOD2 rhythms in horizontally sectioned SCN of mice exposed to a long or short day. Statistical analyses of bioluminescence images with respective luciferase reporters on pixel level enabled us to identify the distinct localization of three oscillating regions; a large open-ring-shape region, the region at the posterior end and a sharply demarcated oval region at the center of the SCN. The first two regions are the respective sites for the so-called evening and morning oscillators, and the third region is possibly a site for mediating photic signals to the former oscillators. In these regions, there are two classes of oscillating cells in which Per1 and Per2 could play differential roles in photoperiodic responses.

  17. Shape memory polymer medical device

    Science.gov (United States)

    Maitland, Duncan [Pleasant Hill, CA; Benett, William J [Livermore, CA; Bearinger, Jane P [Livermore, CA; Wilson, Thomas S [San Leandro, CA; Small, IV, Ward; Schumann, Daniel L [Concord, CA; Jensen, Wayne A [Livermore, CA; Ortega, Jason M [Pacifica, CA; Marion, III, John E.; Loge, Jeffrey M [Stockton, CA

    2010-06-29

    A system for removing matter from a conduit. The system includes the steps of passing a transport vehicle and a shape memory polymer material through the conduit, transmitting energy to the shape memory polymer material for moving the shape memory polymer material from a first shape to a second and different shape, and withdrawing the transport vehicle and the shape memory polymer material through the conduit carrying the matter.

  18. Laser beam shaping techniques

    Energy Technology Data Exchange (ETDEWEB)

    DICKEY,FRED M.; WEICHMAN,LOUIS S.; SHAGAM,RICHARD N.

    2000-03-16

    Industrial, military, medical, and research and development applications of lasers frequently require a beam with a specified irradiance distribution in some plane. A common requirement is a laser profile that is uniform over some cross-section. Such applications include laser/material processing, laser material interaction studies, fiber injection systems, optical data image processing, lithography, medical applications, and military applications. Laser beam shaping techniques can be divided into three areas: apertured beams, field mappers, and multi-aperture beam integrators. An uncertainty relation exists for laser beam shaping that puts constraints on system design. In this paper the authors review the basics of laser beam shaping and present applications and limitations of various techniques.

  19. Deformation-based nuclear morphometry: capturing nuclear shape variation in HeLa cells.

    Science.gov (United States)

    Rohde, Gustavo K; Ribeiro, Alexandre J S; Dahl, Kris N; Murphy, Robert F

    2008-04-01

    The empirical characterization of nuclear shape distributions is an important unsolved problem with many applications in biology and medicine. Numerous genetic diseases and cancers have alterations in nuclear morphology, and methods for characterization of morphology could aid in both diagnoses and fundamental understanding of these disorders. Automated approaches have been used to measure features related to the size and shape of the cell nucleus, and statistical analysis of these features has often been performed assuming an underlying Euclidean (linear) vector space. We discuss the difficulties associated with the analysis of nuclear shape in light of the fact that shape spaces are nonlinear, and demonstrate methods for characterizing nuclear shapes and shape distributions based on spatial transformations that map one nucleus to another. By combining large deformation metric mapping with multidimensional scaling we offer a flexible approach for elucidating the intrinsic nonlinear degrees of freedom of a distribution of nuclear shapes. More specifically, we demonstrate approaches for nuclear shape interpolation and computation of mean nuclear shape. We also provide a method for estimating the number of free parameters that contribute to shape as well as an approach for visualizing most representative shape variations within a distribution of nuclei. The proposed methodology can be completely automated, is independent of the dimensionality of the images, and can handle complex shapes. Results obtained by analyzing two sets of images of HeLa cells are shown. In addition to identifying the modes of variation in normal HeLa nuclei, the effects of lamin A/C on nuclear morphology are quantitatively described. (c) 2007 International Society for Analytical Cytology.

  20. Insulin induces calcium signals in the nucleus of rat hepatocytes.

    Science.gov (United States)

    Rodrigues, Michele A; Gomes, Dawidson A; Andrade, Viviane A; Leite, M Fatima; Nathanson, Michael H

    2008-11-01

    Insulin is an hepatic mitogen that promotes liver regeneration. Actions of insulin are mediated by the insulin receptor, which is a receptor tyrosine kinase. It is currently thought that signaling via the insulin receptor occurs at the plasma membrane, where it binds to insulin. Here we report that insulin induces calcium oscillations in isolated rat hepatocytes, and that these calcium signals depend upon activation of phospholipase C and the inositol 1,4,5-trisphosphate receptor, but not upon extracellular calcium. Furthermore, insulin-induced calcium signals occur in the nucleus, and are temporally associated with selective depletion of nuclear phosphatidylinositol bisphosphate and translocation of the insulin receptor to the nucleus. These findings suggest that the insulin receptor translocates to the nucleus to initiate nuclear, inositol 1,4,5-trisphosphate-mediated calcium signals in rat hepatocytes. This novel signaling mechanism may be responsible for insulin's effects on liver growth and regeneration.

  1. A comparative neuroanatomical study of the red nucleus of the cat, macaque and human.

    Directory of Open Access Journals (Sweden)

    Satoru Onodera

    Full Text Available BACKGROUND: The human red nucleus (Nr is comparatively less well-studied than that of cats or monkeys. Given the functional importance of reticular and midbrain structures in control of movement and locomotion as well as from an evolutionary perspective, we investigated the nature and extent of any differences in Nr projections to the olivary complex in quadrupedal and bipedal species. Using neuroanatomical tract-tracing techniques we developed a "neural sheet" hypothesis allowing us to propose how rubro-olivary relations differ among the three species. METHODS AND FINDINGS: Wheat germ agglutinin-horseradish peroxidase staining supports findings that the cat's nucleus accessories medialis of Bechtrew (NB projects mainly to the lateral bend of the principal olive. We clarified boundaries among nucleus of Darkschewitsch (ND, NB and parvicellular red nucleus (pNr of the cat's neural sheet. The macaque's ND-medial accessory olivary projection is rostro-caudally organized and the dorsomedial and ventrolateral parts of the macaque's pNr may project to the principal olive's rostral and caudal dorsal lamella; in cat it projects as well to pNr. Myelin- and Nissl-stained sections show that a well-developed dorsomedial part of the human Nr consists of densely packed cells, deriving small myelinated fibers that continue into the medial central tegmental tract. CONCLUSIONS: Based on these findings we suggest there are distinct bipedal-quadrupedal differences for Nr projections to the olivary complex. We propose the Nr of cats and monkeys comprise the ND, NB and pNr in a zonal sheet-like structure, retaining clear nuclear boundaries and an isolated, well-developed mNr. The human NB may be distinguished from its more specialised ND (ND lies alongside a well-developed pNr in the human central gray. Phylogenetically, the NB may have been translocated into a roll-shaped Nr in the reticular formation, the dorsomedial portion of which might correspond to the cat

  2. $\\beta$-delayed fission, laser spectroscopy and shape-coexistence studies with radioactive At beams

    CERN Multimedia

    We propose to study the $\\beta$-delayed fission, laser spectroscopy and radioactive decay of the newly available pure beams of neutron-deficient and neutron-rich astatine (Z=85) isotopes. The fission probability and the fission fragment distribution of the even-even isotopes $^{194,196}$Po following the $\\beta$-decay of the isotopes $^{194,196}$At will be studied with the Windmill setup. In-source laser spectroscopy will be performed on the entire astatine isotopic chain, using a combination of the Windmill setup, ISOLTRAP MR-ToF and ISOLDE Faraday. Radioactive decay data will be acquired at the Windmill setup throughout those studies and contribute to the global understanding of the phenomenon of shape coexistence in the neutron-deficient lead region.

  3. Evidence for involvement of the subcoeruleus nucleus and nucleus raphe magnus in urine storage and penile erection in decerebrate rats.

    Science.gov (United States)

    Sugaya, K; Ogawa, Y; Hatano, T; Koyama, Y; Miyazato, T; Oda, M

    1998-06-01

    Micturition and male sexual activity require the lower urinary tract to function. During the sexual act, micturition must be inhibited and urine stored in the bladder. We studied the role of the brainstem in relation to both micturition/urine storage and penile erection in rats. Wire electrodes were placed on the dorsal nerve of the penis and microelectrodes for stimulation were introduced into the brainstem in decerebrate male rats. Electrical stimulation was used to locate optimally responding sites by monitoring the isovolumetric intravesical pressure and intracavernous pressure. Electrical stimulation of the dorsal nerve of the penis, the subcoeruleus nucleus in the rostral pons, and the nucleus raphe magnus in the caudal pons increased intracavernous pressure, but inhibited rhythmic bladder contractions. Electrical stimulation of Barrington's nucleus (the pontine micturition center in the rat) in the rostral pons induced bladder contraction. Stimulation of the pontine reticular formation did not increase intracavernous pressure. Acute transection of the thoracic spinal cord eliminated rhythmic bladder contractions, but gave rise to sporadic increments of intracavernous pressure. This electrophysiological study demonstrated that the subcoeruleus nucleus and nucleus raphe magnus are involved in both urine storage and penile erection, and that their physiological functions are reciprocally controlled; so that erection leads to inhibition of micturition.

  4. 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.

  5. 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. © The

  6. 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.

  7. Intrinsically disordered proteins in the nucleus of human cells.

    Science.gov (United States)

    Frege, Telma; Uversky, Vladimir N

    2015-05-01

    Intrinsically disordered proteins are known to perform a variety of important functions such as macromolecular recognition, promiscuous binding, and signaling. They are crucial players in various cellular pathway and processes, where they often have key regulatory roles. Among vital cellular processes intimately linked to the intrinsically disordered proteins is transcription, an intricate biological performance predominantly developing inside the cell nucleus. With this work, we gathered information about proteins that exist in various compartments and sub-nuclear bodies of the nucleus of the human cells, with the goal of identifying which ones are highly disordered and which functions are ascribed to the disordered nuclear proteins.

  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. 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.

  11. Shaping Adolescent Gambling Behavior.

    Science.gov (United States)

    Arcuri, Alan F.; And Others

    1985-01-01

    Surveyed the incidence of casino gambling by adolescents. Results indicated that 64 percent of the students at one Atlantic City high school had gambled at the casinos. The dangers of shaping compulsive gambling behavior through societal acceptance of legalized gambling are discussed. (Author/BL)

  12. Shape Up Europe

    DEFF Research Database (Denmark)

    Simovska, Venka; Jensen, Bjarne Bruun

    "Shape Up: a School Community Approach to Influencing the Determinants of Childhood Overweight and Obesity, Lessons Learnt" is a report that aims to provide a synthesis of the project overall evaluation documentation, with a view to systematically review and discuss lessons learnt, and to suggest...... recommendations concerning future practice and policy in the area of preventing childhood overweight and obesity....

  13. Aerodynamically shaped vortex generators

    DEFF Research Database (Denmark)

    Hansen, Martin Otto Laver; Velte, Clara Marika; Øye, Stig

    2016-01-01

    An aerodynamically shaped vortex generator has been proposed, manufactured and tested in a wind tunnel. The effect on the overall performance when applied on a thick airfoil is an increased lift to drag ratio compared with standard vortex generators. Copyright © 2015 John Wiley & Sons, Ltd....

  14. Trends Shaping Education 2010

    Science.gov (United States)

    OECD Publishing (NJ3), 2010

    2010-01-01

    "Trends Shaping Education 2010" brings together evidence showing the effects on education of globalisation, social challenges, changes in the workplace, the transformation of childhood, and ICT. To make the content accessible, each trend is presented on a double page, containing an introduction, two charts with brief descriptive text and a set of…

  15. How life shaped Earth.

    Science.gov (United States)

    Gross, Michael

    2015-10-05

    Earth is much more complex than all the other solar system objects that we know. Thanks to its rich and diverse geology, our planet can offer habitats to a wide range of living species. Emerging insights suggest that this is not just a happy coincidence, but that life itself has in many ways helped to shape the planet.

  16. Shaping Faster Question Answering.

    Science.gov (United States)

    Brooks, Lloyd O.

    To test a hypothesis that question answering speed and accuracy can be increased by an automated shaping procedure, a film, "The Analysis of Behavior," was presented individually by a teaching machine during twice-per-week sessions to one high school student and 12 junior college students. Six of the students were informed of monetary rewards for…

  17. Tornado-Shaped Curves

    Science.gov (United States)

    Martínez, Sol Sáez; de la Rosa, Félix Martínez; Rojas, Sergio

    2017-01-01

    In Advanced Calculus, our students wonder if it is possible to graphically represent a tornado by means of a three-dimensional curve. In this paper, we show it is possible by providing the parametric equations of such tornado-shaped curves.

  18. Analysis of () Line Shape

    Indian Academy of Sciences (India)

    The line shape is also simulated by the Monte–Carlo method, the molecular dissociation contributes to 57% neutral atoms and 53% emission intensity in front of the limiter, and 85% neutral atoms and 82% emission intensity in front of the wall. The processes of atoms and molecules influence on the energy balance is ...

  19. Bend me, shape me

    CERN Multimedia

    2002-01-01

    A Japanese team has found a way to bend and shape silicon substrates by growing a thin layer of diamond on top. The technique has been proposed as an alternative to mechanical bending, which is currently used to make reflective lenses for X-ray systems and particle physics systems (2 paragraphs).

  20. Ferromagnetic shape memory alloys

    Indian Academy of Sciences (India)

    ugc

    (sensor), magnetocaloric (refrigeration), and shape memory effect. (actuation) may be important for their future application. Magnetoresistance (8%). Giant magnetocaloric ..... Experimental studies on Ga. 2. MnNi: SEM, EDAX, DSC. T. M. = 780 K. Homogeneous, composition Ga. 1.9. Mn. 0.8. Ni. 1.02. Secondary electron ...

  1. Geologic analysis of the Rosetta NavCam, Osiris and ROLIS images of the comet 67P/Churyumov-Gerasimenko nucleus

    Science.gov (United States)

    Basilevsky, A. T.; Mall, U.; Keller, H. U.; Skorov, Yu. V.; Hviid, S. F.; Mottola, S.; Krasilnikov, S. S.; Dabrowski, B.

    2017-03-01

    This paper is based on geologic analysis of the surface morphology of nucleus of the Jupiter family comet 67P. This comet was visited by the ESA mission Rosetta, which escorted the comet since May 2014 till the end of September 2016 and studied it by 11 instruments of the mission orbiter and 10 instruments of the lander. The nucleus is 4 km in diameter, has a bilobate shape with the smaller (Head) and larger (Body) lobes, and the narrow neck between them. For the analysis, primarily images taken by the Rosetta Navigation camera (NavCam) were used and then complemented by selected images from the ROLIS and OSIRIS cameras. Two major types of the nucleus material are distinguished by us and other researchers: 1) the consolidated nucleus material and 2) the loose material, a kind of cometary regolith, covering the nucleus consolidated material. On the surface of the consolidated material rather long (up to hundreds meters) straight lineaments are distinguishable. They probably correspond to fractures and in some cases to strata. Their presence suggests that the consolidated material is rather compact and lacks voids larger than tens of meters across. Surfaces of consolidated nucleus material typically show knobby appearance at the scales from tens of meters and meters to centimeters and millimeters. This suggests that this material is grainy, consisting of more and less resistant (to surface weathering) ;particles; on the scale of the visible knobs. The geometric analysis of steep slopes based on the nucleus shape model allowed us to estimate a tensile, shear and compressive strength of the consolidated material. It was shown that the 67P consolidated nucleus material is very fragile, and taking into account the scale effect one can conclude that it is as fragile as fresh fallen snow and maybe even more fragile. In addition, estimates of the compressive strength of the surface material were considered at the sites of the first and the last contacts of the Philae lander

  2. Duality based contact shape optimization

    DEFF Research Database (Denmark)

    Vondrák, Vít; Dostal, Zdenek; Rasmussen, John

    2001-01-01

    An implementation of semi-analytic method for the sensitivity analysis in contact shape optimization without friction is described. This method is then applied to the contact shape optimization.......An implementation of semi-analytic method for the sensitivity analysis in contact shape optimization without friction is described. This method is then applied to the contact shape optimization....

  3. Nucleus geometry and mechanical properties of resistance spot ...

    Indian Academy of Sciences (India)

    show that nugget diameter, indentation depth and tensile load-bearing capacity are affected by weld parameters. Coating prevents full joining at low parameters. Microhardness increased in heat-affected zone and weld metal. Keywords. Automotive steels; resistance spot welding; mechanical properties; nucleus geometry.

  4. Study of the variability of the nucleus of Centaurus A.

    Science.gov (United States)

    Fernandes de Mello Rabaca, D.; Abraham, Z.

    1990-11-01

    ABSTRACT. This work consists in the study of the variability of the nucleus of the peculiar galaxy NGC 5128 (Centaurus A) at the radio continuum frequency of 43 GHz. The data were obtained with the 13.7 m itapetinga Radiotelescope. The radio source presents a pair of inner radio lobes and a compact variable nucleus. The observational technique used was scans through the inner radio lobes and the nucleus. The quasi- simultaneous measurements of the flux density of each source allowed us to derive accurately the relative flux between them, and to obtain the real variability of the nucleus. RESUMO. Este trabalho consiste no estudo da variabilidade do nucleo da galaxia peculiar NGC 5128 (Centaurus A) no de radio na de 43 GHz. Os dados foram obtidos com 0 Radiotelescopio do Itapetinga. A radio fonte apresenta um par de lobulos internos e um nucleo compacto variavel. A tetnica observacional utilizada foi a de varreduras passando pelos lobulos e pelo nucleo. As medidas quase simultaneas da densidade de fluxo de cada fonte permitiu obter precisa- mente 0 fluxo relativo entre elas e a variabilidade real do nucleo. Keq woit : GALAXIES-RADIO

  5. 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

  6. Subthalamic nucleus stimulation reverses mediofrontal influence over decision threshold

    NARCIS (Netherlands)

    Cavanagh, J.F.; Wiecki, T.V.; Cohen, M.X.; Figueroa, C.M.; Samanta, J.; Sherman, S.J.; Frank, M.J.

    2011-01-01

    It takes effort and time to tame one's impulses. Although medial prefrontal cortex (mPFC) is broadly implicated in effortful control over behavior, the subthalamic nucleus (STN) is specifically thought to contribute by acting as a brake on cortico-striatal function during decision conflict, buying

  7. Inelastic magnetic electron scattering form factors of the Mg nucleus

    Indian Academy of Sciences (India)

    states of the 26Mg nucleus have been studied using shell model calculations. The universal sd of the Wildenthal interaction, universal sd-shell interaction A, universal sd-shell interaction B, are used for the sd-shell orbits. Core polarization effects accord- ing to microscopic theory are taken into account by the excitations of ...

  8. Nuclear structure in odd-odd nucleus [sup 138]Pr

    Energy Technology Data Exchange (ETDEWEB)

    Rizzutto, M.A.; Cybulska, E.W.; Vanin, V.R.; Oliveira, J.R.B.; Emediato, L.G.R.; Ribas, R.V.; Seale, W.A.; Rao, M.N.; Medina, N.H.; Botelho, S.; Acquadro, J.C.; Lima, C.L. (Sao Paulo Univ., SP (Brazil). Lab. Pelletron)

    1992-12-01

    With the view of extending the systematics of odd-odd Pr nuclei toward the N=82 closed shell, high-spin states in [sup 138]Pr nucleus have been investigated with the [sup 128]Te([sup 14]N, 4n[gamma]) reaction. Configurations and spin assignments are suggested for three of the observed band-structures. (orig.).

  9. Sex hormone receptors are present in the human suprachiasmatic nucleus

    NARCIS (Netherlands)

    Kruijver, Frank P. M.; Swaab, Dick F.

    2002-01-01

    The suprachiasmatic nucleus (SCN) is the clock of the brain that orchestrates circadian and circannual biological rhythms, such as the rhythms of hormones, body temperature, sleep and mood. These rhythms are frequently disturbed in menopause and even more so in dementia and can be restored in

  10. KINEMATIC DETECTION OF THE DOUBLE NUCLEUS IN M31

    NARCIS (Netherlands)

    GERSSEN, J; KUIJKEN, K; MERRIFIELD, MR

    1995-01-01

    Using a spectrum obtained under moderate (similar to 1 arcsec) seeing, we show that the double nucleus in M31 produces a strong kinematic signature even though the individual components are not spatially resolved. The signature consists of a significant asymmetric wing in the stellar velocity

  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. Calcium-regulated import of myosin IC into the nucleus.

    Science.gov (United States)

    Maly, Ivan V; Hofmann, Wilma A

    2016-06-01

    Myosin IC is a molecular motor involved in intracellular transport, cell motility, and transcription. Its mechanical properties are regulated by calcium via calmodulin binding, and its functions in the nucleus depend on import from the cytoplasm. The import has recently been shown to be mediated by the nuclear localization signal located within the calmodulin-binding domain. In the present paper, it is demonstrated that mutations in the calmodulin-binding sequence shift the intracellular distribution of myosin IC to the nucleus. The redistribution is displayed by isoform B, described originally as the "nuclear myosin," but is particularly pronounced with isoform C, the normally cytoplasmic isoform. Furthermore, experimental elevation of the intracellular calcium concentration induces a rapid import of myosin into the nucleus. The import is blocked by the importin β inhibitor importazole. These findings are consistent with a mechanism whereby calmodulin binding prevents recognition of the nuclear localization sequence by importin β, and the steric inhibition of import is released by cell signaling leading to the intracellular calcium elevation. The results establish a mechanistic connection between the calcium regulation of the motor function of myosin IC in the cytoplasm and the induction of its import into the nucleus. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  13. Nitric oxide and reactive oxygen species in the nucleus revisited.

    Science.gov (United States)

    Provost, Chantale; Choufani, Faten; Avedanian, Levon; Bkaily, Ghassan; Gobeil, Fernand; Jacques, Danielle

    2010-03-01

    Recent work from our group showed that the nuclear envelope membranes contain several G protein-coupled receptors, including prostaglandin E2 (EP3R) and endothelin-1 (ET-1) receptors. Activation of EP3R increased endothelial nitric oxide synthase (eNOS) RNA expression in nuclei. eNOS and inducible NOS (iNOS) are reported to also be present at the nuclear level. Furthermore, reactive oxygen species (ROS) were also localized at the nuclear level. In this review, we show that stimulation with NO donor sodium nitroprusside results in an increase of intranuclear calcium that was dependent on guanylate cyclase activation, but independent of MAPK. This increase in nuclear calcium correlated with an increase in nuclear transcription of iNOS. H2O2 and ET-1 increase both cytosolic and nuclear ROS in human endocardial endothelial cells and in human aortic vascular smooth muscle cells. This increase in ROS levels by H2O2 and ET-1 was reversed by the antioxidant glutathione. In addition, our results strongly suggest that cytosolic signalization is not only transmitted to the nucleus but is also generated by the nucleus. Furthermore, we demonstrate that oxidative stress can be sensed by the nucleus. These results highly suggest that ROS formation is also generated directly by the nucleus and that free radicals may contribute to ET-1 regulation of nuclear Ca2+ homeostasis.

  14. Inclusive jet production in ultrarelativistic proton-nucleus collisions

    CERN Document Server

    Perepelitsa, Dennis

    High-$p_\\mathrm{T}$ processes in proton- and deuteron-nucleus collisions at TeV energies are the best presently available way to study the partonic structure of the nucleus in a high-density regime. Jet production over a wide range of phase space can significantly constrain the current knowledge of nuclear parton distribution functions (nPDFs), which are substantially less well understood than the corresponding PDFs in protons and which have only recently begun to be treated in a spatially-dependent way. An accurate knowledge of nPDFs is crucial for a definitive control of perturbative processes in a cold nuclear environment, since high-$p_\\mathrm{T}$ probes are used to quantitatively investigate the hot QCD matter created in ultrarelativistic nucleus-nucleus collisions. Furthermore, jets from low Bjorken-$x$ partons can probe the transition from the dilute to saturated nuclear regimes. Jet production is investigated in $d$+Au collisions at $\\sqrt{s} = 200$ GeV with the PHENIX detector at the Relativistic Hea...

  15. Cortically evoked potentials in the human subthalamic nucleus

    NARCIS (Netherlands)

    Zwartjes - de Klerk, D.G.M; Janssen, M.L.F; Heida, Tjitske; van Kranen-Mastenbroek, V.; Bour, L.; Temel, Y.; Visser-Vandewalle, V.; Martens, H.C.F.; Veltink, Petrus H.

    2013-01-01

    Deep brain stimulation (DBS) of the subthalamic nucleus (STN) alleviates motor symptoms in Parkinson’s disease (PD) patients. However, in a substantial number of patients the beneficial effects of STN DBS are overshadowed by psychiatric side effects. We hypothesize that stimulation of the STN motor

  16. Saturating Cronin effect in ultrarelativistic proton-nucleus collisions

    OpenAIRE

    Papp, Gabor; Levai, Peter; Fai, George

    1999-01-01

    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.

  17. 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. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  18. Glucocorticoids suppress vasopressin gene expression in human suprachiasmatic nucleus.

    NARCIS (Netherlands)

    Liu, R.-Y.; Unmehopa, U.A.; Zhou, J.-N.; Swaab, D.F.

    2006-01-01

    Sleep impairment is one of the major side effects of glucocorticoid therapy. The mechanism responsible for this circadian disorder is unknown, but alterations in the suprachiasmatic nucleus (SCN), the biological clock of the human brain, are presumed to play a major role. In the present study, the

  19. Glucocorticoids suppress vasopressin gene expression in human suprachiasmatic nucleus

    NARCIS (Netherlands)

    Liu, Rong-Yu; Unmehopa, Unga A.; Zhou, Jiang-Ning; Swaab, Dick F.

    2006-01-01

    Sleep impairment is one of the major side effects of glucocorticoid therapy. The mechanism responsible for this circadian disorder is unknown, but alterations in the suprachiasmatic nucleus (SCN), the biological clock of the human brain, are presumed to play a major role. In the present study, the

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

    Science.gov (United States)

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

    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

  1. Breathing Life into Shapes.

    Science.gov (United States)

    Jacobson, Alec

    2015-01-01

    Shape articulation transforms a lifeless geometric object into a vibrant character. Computers enrich artists' toolsets dramatically. They not only endow artists with the power to manipulate virtual 2D and 3D scenes, but they also eliminate tedium and expedite prototyping, freeing artists to focus on creative aspects. With such power comes a temptation to lean entirely on the computer. Computationally intensive animation systems sacrifice real-time feedback for physical accuracy. How can we leverage modern computational power to create the best possible shape deformations while maintaining real-time performance as a mandatory invariant? This article summarizes efforts to answer this, culminating in a deformation system with the quality of slow, nonlinear optimization, but at lightning speed.

  2. Shaping the Social

    DEFF Research Database (Denmark)

    Andersen, Susan; Tolstrup, Janne Schurmann; Rod, Morten Hulvej

    2015-01-01

    BACKGROUND: The social environment at schools is an important setting to promote educational attainment, and health and well-being of young people. However, within upper secondary education there is a need for evidence-based school intervention programmes. The Shaping the Social intervention...... is a comprehensive programme integrating social and educational activities to promote student well-being and reduce smoking and dropout in upper secondary vocational education. The evaluation design is reported here. METHODS/DESIGN: The evaluation employed a non-randomised cluster controlled design, and schools were...... national education registers through a 2-year follow-up period. DISCUSSION: Shaping the Social was designed to address that students at Danish vocational schools constitute a high risk population concerning health behaviour as well as school dropout by modifying the school environment, alongside developing...

  3. Shape Changing Airfoil

    Science.gov (United States)

    Ott, Eric A.

    2005-01-01

    Scoping of shape changing airfoil concepts including both aerodynamic analysis and materials-related technology assessment effort was performed. Three general categories of potential components were considered-fan blades, booster and compressor blades, and stator airfoils. Based on perceived contributions to improving engine efficiency, the fan blade was chosen as the primary application for a more detailed assessment. A high-level aerodynamic assessment using a GE90-90B Block 4 engine cycle and fan blade geometry indicates that blade camber changes of approximately +/-4deg would be sufficient to result in fan efficiency improvements nearing 1 percent. Constraints related to flight safety and failed mode operation suggest that use of the baseline blade shape with actuation to the optimum cruise condition during a portion of the cycle would be likely required. Application of these conditions to the QAT fan blade and engine cycle was estimated to result in an overall fan efficiency gain of 0.4 percent.

  4. Shaping the Social

    DEFF Research Database (Denmark)

    Andersen, Susan; Tolstrup, Janne Schurmann; Rod, Morten Hulvej

    2015-01-01

    is a comprehensive programme integrating social and educational activities to promote student well-being and reduce smoking and dropout in upper secondary vocational education. The evaluation design is reported here. METHODS/DESIGN: The evaluation employed a non-randomised cluster controlled design, and schools were......BACKGROUND: The social environment at schools is an important setting to promote educational attainment, and health and well-being of young people. However, within upper secondary education there is a need for evidence-based school intervention programmes. The Shaping the Social intervention...... national education registers through a 2-year follow-up period. DISCUSSION: Shaping the Social was designed to address that students at Danish vocational schools constitute a high risk population concerning health behaviour as well as school dropout by modifying the school environment, alongside developing...

  5. Social Shaping of Innovation

    DEFF Research Database (Denmark)

    Buur, Jacob; Mack, Alexandra

    - in particular in a large corporation? This workshop explores how innovation is socially shaped in organizations. Based on our experiences with practices around innovation and collaboration, we start from three proposition about the social shaping of innovation: • Ideas don't thrive as text (i.e. we need......Why is it that some business proposals – no matter how well researched with users and business developed – don’t seem to make it through the organizational jungle to become a real product, while others do? How shall we understand the innovative practices that we engage with our ethnographic work...... to consider other media) • Ideas need socialization (ideas are linked to people, we need to be careful about how we support the social innovation context) • Ideas are local (ideas spring out of a local contingency, we need to take care in how we like them to travel)....

  6. Biomedical Shape Memory Polymers

    Directory of Open Access Journals (Sweden)

    SHEN Xue-lin

    2017-07-01

    Full Text Available Shape memory polymers(SMPs are a class of functional "smart" materials that have shown bright prospects in the area of biomedical applications. The novel smart materials with multifunction of biodegradability and biocompatibility can be designed based on their general principle, composition and structure. In this review, the latest process of three typical biodegradable SMPs(poly(lactide acide, poly(ε-caprolactone, polyurethane was summarized. These three SMPs were classified in different structures and discussed, and shape-memory mechanism, recovery rate and fixed rate, response speed was analysed in detail, also, some biomedical applications were presented. Finally, the future development and applications of SMPs are prospected: two-way SMPs and body temperature induced SMPs will be the focus attension by researchers.

  7. Role of nucleus accumbens glutamatergic plasticity in drug addiction

    Directory of Open Access Journals (Sweden)

    Quintero GC

    2013-09-01

    Full Text Available Gabriel C Quintero1–31Florida State University – Panama, Clayton, Panama; 2Medical University of South Carolina, Charleston, South Carolina, USA; 3Smithsonian Tropical Research Institute, Ancon, Republic of PanamaAbstract: Substance dependence is characterized by a group of symptoms, according to the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition, Text Revision (DSM-IV-TR. These symptoms include tolerance, withdrawal, drug consumption for alleviating withdrawal, exaggerated consumption beyond original intention, failure to reduce drug consumption, expending a considerable amount of time obtaining or recovering from the substance’s effects, disregard of basic aspects of life (for example, family, and maintenance of drug consumption, despite facing adverse consequences. The nucleus accumbens (NAc is a brain structure located in the basal forebrain of vertebrates, and it has been the target of addictive drugs. Different neurotransmitter systems at the level of the NAc circuitry have been linked to the different problems of drug addiction, like compulsive use and relapse. The glutamate system has been linked mainly to relapse after drug-seeking extinction. The dopamine system has been linked mainly to compulsive drug use. The glutamate homeostasis hypothesis centers around the dynamics of synaptic and extrasynaptic levels of glutamate, and their impact on circuitry from the prefrontal cortex (PFC to the NAc. After repetitive drug use, deregulation of this homeostasis increases the release of glutamate from the PFC to the NAc during drug relapse. Glial cells also play a fundamental role in this hypothesis; glial cells shape the interactions between the PFC and the NAc by means of altering glutamate levels in synaptic and extrasynaptic spaces. On the other hand, cocaine self-administration and withdrawal increases the surface expression of subunit glutamate receptor 1 (GluA1 of alpha-amino-3-hydroxy-5-methyl-4

  8. Audiometric shape and presbycusis.

    Science.gov (United States)

    Demeester, Kelly; van Wieringen, Astrid; Hendrickx, Jan-jaap; Topsakal, Vedat; Fransen, Erik; van Laer, Lut; Van Camp, Guy; Van de Heyning, Paul

    2009-04-01

    The aim of this study was to describe the prevalence of specific audiogram configurations in a healthy, otologically screened population between 55 and 65 years old. The audiograms of 1147 subjects (549 males and 598 females between 55 and 65 years old) were collected through population registries and classified according to the configuration of hearing loss. Gender and noise/solvent-exposure effects on the prevalence of the different audiogram shapes were determined statistically. In our population 'Flat' audiograms were most dominantly represented (37%) followed by 'High frequency Gently sloping' audiograms (35%) and 'High frequency Steeply sloping' audiograms (27%). 'Low frequency Ascending' audiograms, 'Mid frequency U-shape' audiograms and 'Mid frequency Reverse U-shape' audiograms were very rare (together less than 1%). The 'Flat'-configuration was significantly more common in females, whereas the 'High frequency Steeply sloping'-configuration was more common in males. Exposure to noise and/or solvents did not change this finding. In addition, females with a 'Flat' audiogram had a significantly larger amount of overall hearing loss compared to males. Furthermore, our data reveal a significant association between the prevalence of 'High frequency Steeply sloping' audiograms and the degree of noise/solvent exposure, despite a relatively high proportion of non-exposed subjects showing a 'High frequency Steeply sloping' audiogram as well.

  9. 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

  10. Cochlear nucleus neuron analysis in individuals with presbycusis.

    Science.gov (United States)

    Hinojosa, Raul; Nelson, Erik G

    2011-12-01

    The aim of this study was to analyze the cochlear nucleus neuron population in individuals with normal hearing and presbycusis. Retrospective study of archival human temporal bone and brain stem tissues. Using strict inclusion criteria, the temporal bones and cochlear nuclei from six normal hearing individuals and four individuals with presbycusis were selected for analysis. The spiral ganglion cell population, the cochlear nucleus neuron population, and the cell body size of the neurons were quantified in these cases. A relationship was not observed between age and the spiral ganglion cell population in the normal hearing group. Presbycusis subjects exhibited a reduced spiral ganglion cell population. The mean cochlear nucleus neuron population was observed to be significantly higher in the presbycusis group (mean ± standard deviation: 114,170 ± 10,570) compared to the normal hearing group (91,470 ± 9,510) (P = .019). This difference was predominantly the result of greater multipolar and granule cell neuron populations. Only the fusiform neuron type exhibited a significantly different mean cell body cross-sectional area between the normal hearing group (242 ± 27) and the presbycusis group (300 ± 37) (P = .033). This investigation is the first time, to our knowledge, that the populations of the eight neuron types in the cochlear nucleus have been quantified in both normal hearing individuals and individuals with presbycusis. The data support the concept that presbycusis is not an effect of aging alone but instead may be a condition that predisposes one to hearing loss with advancing age and is characterized by a congenitally elevated cochlear nucleus neuron population. Copyright © 2011 The American Laryngological, Rhinological, and Otological Society, Inc.

  11. Role of nucleus accumbens glutamatergic plasticity in drug addiction.

    Science.gov (United States)

    Quintero, Gabriel C

    2013-01-01

    Substance dependence is characterized by a group of symptoms, according to the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition, Text Revision (DSM-IV-TR). These symptoms include tolerance, withdrawal, drug consumption for alleviating withdrawal, exaggerated consumption beyond original intention, failure to reduce drug consumption, expending a considerable amount of time obtaining or recovering from the substance's effects, disregard of basic aspects of life (for example, family), and maintenance of drug consumption, despite facing adverse consequences. The nucleus accumbens (NAc) is a brain structure located in the basal forebrain of vertebrates, and it has been the target of addictive drugs. Different neurotransmitter systems at the level of the NAc circuitry have been linked to the different problems of drug addiction, like compulsive use and relapse. The glutamate system has been linked mainly to relapse after drug-seeking extinction. The dopamine system has been linked mainly to compulsive drug use. The glutamate homeostasis hypothesis centers around the dynamics of synaptic and extrasynaptic levels of glutamate, and their impact on circuitry from the prefrontal cortex (PFC) to the NAc. After repetitive drug use, deregulation of this homeostasis increases the release of glutamate from the PFC to the NAc during drug relapse. Glial cells also play a fundamental role in this hypothesis; glial cells shape the interactions between the PFC and the NAc by means of altering glutamate levels in synaptic and extrasynaptic spaces. On the other hand, cocaine self-administration and withdrawal increases the surface expression of subunit glutamate receptor 1 (GluA1) of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors at the level of the NAc. Also, cocaine self-administration and withdrawal induce the formation of subunit glutamate receptor 2 (GluA2), lacking the Ca(2+)-permeable AMPA receptors (CP-AMPARs) at the level of the NAc

  12. Towards robust and effective shape modeling: sparse shape composition.

    Science.gov (United States)

    Zhang, Shaoting; Zhan, Yiqiang; Dewan, Maneesh; Huang, Junzhou; Metaxas, Dimitris N; Zhou, Xiang Sean

    2012-01-01

    Organ shape plays an important role in various clinical practices, e.g., diagnosis, surgical planning and treatment evaluation. It is usually derived from low level appearance cues in medical images. However, due to diseases and imaging artifacts, low level appearance cues might be weak or misleading. In this situation, shape priors become critical to infer and refine the shape derived by image appearances. Effective modeling of shape priors is challenging because: (1) shape variation is complex and cannot always be modeled by a parametric probability distribution; (2) a shape instance derived from image appearance cues (input shape) may have gross errors; and (3) local details of the input shape are difficult to preserve if they are not statistically significant in the training data. In this paper we propose a novel Sparse Shape Composition model (SSC) to deal with these three challenges in a unified framework. In our method, a sparse set of shapes in the shape repository is selected and composed together to infer/refine an input shape. The a priori information is thus implicitly incorporated on-the-fly. Our model leverages two sparsity observations of the input shape instance: (1) the input shape can be approximately represented by a sparse linear combination of shapes in the shape repository; (2) parts of the input shape may contain gross errors but such errors are sparse. Our model is formulated as a sparse learning problem. Using L1 norm relaxation, it can be solved by an efficient expectation-maximization (EM) type of framework. Our method is extensively validated on two medical applications, 2D lung localization in X-ray images and 3D liver segmentation in low-dose CT scans. Compared to state-of-the-art methods, our model exhibits better performance in both studies. Copyright © 2011 Elsevier B.V. All rights reserved.

  13. Abstract shape analysis of RNA.

    Science.gov (United States)

    Janssen, Stefan; Giegerich, Robert

    2014-01-01

    Abstract shape analysis abstract shape analysis is a method to learn more about the complete Boltzmann ensemble of the secondary structures of a single RNA molecule. Abstract shapes classify competing secondary structures into classes that are defined by their arrangement of helices. It allows us to compute, in addition to the structure of minimal free energy, a set of structures that represents relevant and interesting structural alternatives. Furthermore, it allows to compute probabilities of all structures within a shape class. This allows to ensure that our representative subset covers the complete Boltzmann ensemble, except for a portion of negligible probability. This chapter explains the main functions of abstract shape analysis, as implemented in the tool RNA shapes. RNA shapes It reports on some other types of analysis that are based on the abstract shapes idea and shows how you can solve novel problems by creating your own shape abstractions.

  14. Two independent and primitive envelopes of the bilobate nucleus of comet 67P.

    Science.gov (United States)

    Massironi, Matteo; Simioni, Emanuele; Marzari, Francesco; Cremonese, Gabriele; Giacomini, Lorenza; Pajola, Maurizio; Jorda, Laurent; Naletto, Giampiero; Lowry, Stephen; El-Maarry, Mohamed Ramy; Preusker, Frank; Scholten, Frank; Sierks, Holger; Barbieri, Cesare; Lamy, Philippe; Rodrigo, Rafael; Koschny, Detlef; Rickman, Hans; Keller, Horst Uwe; A'Hearn, Michael F; Agarwal, Jessica; Auger, Anne-Thérèse; Barucci, M Antonella; Bertaux, Jean-Loup; Bertini, Ivano; Besse, Sebastien; Bodewits, Dennis; Capanna, Claire; Da Deppo, Vania; Davidsson, Björn; Debei, Stefano; De Cecco, Mariolino; Ferri, Francesca; Fornasier, Sonia; Fulle, Marco; Gaskell, Robert; Groussin, Olivier; Gutiérrez, Pedro J; Güttler, Carsten; Hviid, Stubbe F; Ip, Wing-Huen; Knollenberg, Jörg; Kovacs, Gabor; Kramm, Rainer; Kührt, Ekkehard; Küppers, Michael; La Forgia, Fiorangela; Lara, Luisa M; Lazzarin, Monica; Lin, Zhong-Yi; Lopez Moreno, Josè J; Magrin, Sara; Michalik, Harald; Mottola, Stefano; Oklay, Nilda; Pommerol, Antoine; Thomas, Nicolas; Tubiana, Cecilia; Vincent, Jean-Baptiste

    2015-10-15

    The factors shaping cometary nuclei are still largely unknown, but could be the result of concurrent effects of evolutionary and primordial processes. The peculiar bilobed shape of comet 67P/Churyumov-Gerasimenko may be the result of the fusion of two objects that were once separate or the result of a localized excavation by outgassing at the interface between the two lobes. Here we report that the comet's major lobe is enveloped by a nearly continuous set of strata, up to 650 metres thick, which are independent of an analogous stratified envelope on the minor lobe. Gravity vectors computed for the two lobes separately are closer to perpendicular to the strata than those calculated for the entire nucleus and adjacent to the neck separating the two lobes. Therefore comet 67P/Churyumov-Gerasimenko is an accreted body of two distinct objects with 'onion-like' stratification, which formed before they merged. We conclude that gentle, low-velocity collisions occurred between two fully formed kilometre-sized cometesimals in the early stages of the Solar System. The notable structural similarities between the two lobes of comet 67P/Churyumov-Gerasimenko indicate that the early-forming cometesimals experienced similar primordial stratified accretion, even though they formed independently.

  15. 3D segmentation of annulus fibrosus and nucleus pulposus from T2-weighted magnetic resonance images

    Science.gov (United States)

    Castro-Mateos, Isaac; Pozo, Jose M.; Eltes, Peter E.; Del Rio, Luis; Lazary, Aron; Frangi, Alejandro F.

    2014-12-01

    Computational medicine aims at employing personalised computational models in diagnosis and treatment planning. The use of such models to help physicians in finding the best treatment for low back pain (LBP) is becoming popular. One of the challenges of creating such models is to derive patient-specific anatomical and tissue models of the lumbar intervertebral discs (IVDs), as a prior step. This article presents a segmentation scheme that obtains accurate results irrespective of the degree of IVD degeneration, including pathological discs with protrusion or herniation. The segmentation algorithm, employing a novel feature selector, iteratively deforms an initial shape, which is projected into a statistical shape model space at first and then, into a B-Spline space to improve accuracy. The method was tested on a MR dataset of 59 patients suffering from LBP. The images follow a standard T2-weighted protocol in coronal and sagittal acquisitions. These two image volumes were fused in order to overcome large inter-slice spacing. The agreement between expert-delineated structures, used here as gold-standard, and our automatic segmentation was evaluated using Dice Similarity Index and surface-to-surface distances, obtaining a mean error of 0.68 mm in the annulus segmentation and 1.88 mm in the nucleus, which are the best results with respect to the image resolution in the current literature.

  16. The types of neurons of the somatic oculomotor nucleus in the European bison. Nissl and Golgi studies.

    Science.gov (United States)

    Szteyn, S; Robak, A; Równiak, M

    1997-01-01

    The neuronal structure of the somatic oculomotor nucleus (SON) was studied on the basis of Nissl and Golgi preparations, obtained from mesencephalons of 4 European bisons. We distinguished four types of neurons in the investigated nucleus: 1. The large multipolar nerve cells with 5-8 thick dendritic trunks and a thin axon which emerges directly from the soma. These are the most numerous neurons in the SON. 2. The small multipolar neurons. These cells have 4-6 thick dendritic trunks. An axon arises mostly from initial segment of one of the dendrites. This type represents about 8% neurons of SON. 3. The triangular neurons. From perikaryon 3 thick dendritic trunks emerge. A thin axon arises directly from the cell body. These cells make about 10% neurons of SON. 4. The pear-shaped cells which have 1 or 2 dendritic trunks concentrate at one pole of the neurons. In the SON there are about 2% pear-shaped cells. Their features correspond to the features attributed by many authors to the interneurons.

  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. IHW COMET HALLEY NEAR NUCLEUS IMAGE DATA, V2.0

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set presents images of the nucleus of comet 1P/Halley obtained by the various contributing observers of the International Halley Watch (IHW) Near-Nucleus...

  19. Anatomical evidence for direct connections between the shell and core subregions of the rat nucleus accumbens

    NARCIS (Netherlands)

    van Dongen, Y.C.; Deniau, J.M.; Pennartz, C.M.A.; Galis-de Graaf, Y.; Voorn, P.; Thierry, A.M.; Groenewegen, H.J.

    2005-01-01

    The nucleus accumbens is thought to subserve different aspects of adaptive and emotional behaviors. The anatomical substrates for such actions are multiple, parallel ventral striatopallidal output circuits originating in the nucleus accumbens shell and core subregions. Several indirect ways of

  20. 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)...

  1. Responses of primate caudal parabrachial nucleus and Kolliker-fuse nucleus neurons to whole body rotation

    Science.gov (United States)

    Balaban, Carey D.; McGee, David M.; Zhou, Jianxun; Scudder, Charles A.

    2002-01-01

    The caudal aspect of the parabrachial (PBN) and Kolliker-Fuse (KF) nuclei receive vestibular nuclear and visceral afferent information and are connected reciprocally with the spinal cord, hypothalamus, amygdala, and limbic cortex. Hence, they may be important sites of vestibulo-visceral integration, particularly for the development of affective responses to gravitoinertial challenges. Extracellular recordings were made from caudal PBN cells in three alert, adult female Macaca nemestrina through an implanted chamber. Sinusoidal and position trapezoid angular whole body rotation was delivered in yaw, roll, pitch, and vertical semicircular canal planes. Sites were confirmed histologically. Units that responded during rotation were located in lateral and medial PBN and KF caudal to the trochlear nerve at sites that were confirmed anatomically to receive superior vestibular nucleus afferents. Responses to whole-body angular rotation were modeled as a sum of three signals: angular velocity, a leaky integration of angular velocity, and vertical position. All neurons displayed angular velocity and integrated angular velocity sensitivity, but only 60% of the neurons were position-sensitive. These responses to vertical rotation could display symmetric, asymmetric, or fully rectified cosinusoidal spatial tuning about a best orientation in different cells. The spatial properties of velocity and integrated velocity and position responses were independent for all position-sensitive neurons; the angular velocity and integrated angular velocity signals showed independent spatial tuning in the position-insensitive neurons. Individual units showed one of three different orientations of their excitatory axis of velocity rotation sensitivity: vertical-plane-only responses, positive elevation responses (vertical plane plus ipsilateral yaw), and negative elevation axis responses (vertical plane plus negative yaw). The interactions between the velocity and integrated velocity components

  2. Regional Difference in Sex Steroid Action on Formation of Morphological Sex Differences in the Anteroventral Periventricular Nucleus and Principal Nucleus of the Bed Nucleus of the Stria Terminalis

    Science.gov (United States)

    Kanaya, Moeko; Tsuda, Mumeko C.; Sagoshi, Shoko; Nagata, Kazuyo; Morimoto, Chihiro; Tha Thu, Chaw Kyi; Toda, Katsumi; Kato, Shigeaki; Ogawa, Sonoko; Tsukahara, Shinji

    2014-01-01

    Sex steroid action is critical to form sexually dimorphic nuclei, although it is not fully understood. We previously reported that masculinization of the principal nucleus of the bed nucleus of the stria terminalis (BNSTp), which is larger and has more neurons in males than in females, involves aromatized testosterone that acts via estrogen receptor-α (ERα), but not estrogen receptor-β (ERβ). Here, we examined sex steroid action on the formation of the anteroventral periventricular nucleus (AVPV) that is larger and has more neurons in females. Morphometrical analysis of transgenic mice lacking aromatase, ERα, or ERβ genes revealed that the volume and neuron number of the male AVPV were significantly increased by deletion of aromatase and ERα genes, but not the ERβ gene. We further examined the AVPV and BNSTp of androgen receptor knockout (ARKO) mice. The volume and neuron number of the male BNSTp were smaller in ARKO mice than those in wild-type mice, while no significant effect of ARKO was found on the AVPV and female BNSTp. We also examined aromatase, ERα, and AR mRNA levels in the AVPV and BNSTp of wild-type and ARKO mice on embryonic day (ED) 18 and postnatal day (PD) 4. AR mRNA in the BNSTp and AVPV of wild-type mice was not expressed on ED18 and emerged on PD4. In the AVPV, the aromatase mRNA level was higher on ED18, although the ERα mRNA level was higher on PD4 without any effect of AR gene deletion. Aromatase and ERα mRNA levels in the male BNSTp were significantly increased on PD4 by AR gene deletion. These results suggest that estradiol signaling via ERα during the perinatal period and testosterone signaling via AR during the postnatal period are required for masculinization of the BNSTp, whereas the former is sufficient to defeminize the AVPV. PMID:25398007

  3. Dynamics of landslides on comets of irregular shape

    Science.gov (United States)

    Czechowski, Leszek

    2017-04-01

    Landslides were observed on a few comet's nuclei, e.g. [1], [2]. The mechanism of their origin is not obvious because of very low gravity. According to [2] fluidization and multiphase transport of cometary material could be an explanation. We investigate here motion of the mass on a comet of irregular shape. The mechanism responsible for the low friction is not considered here. In fact, mass motion often occurs without contact with the surface. The motion could be triggered by meteoroids impacts or by the tidal forces. Comets nuclei are believed to be built of soft materials like snow and dust. The landing of Philae on the comet 67P/Czuriumow-Gierasimienko indicates a different situation. According to [1]: "thermal probe did not fully penetrate the near-surface layers, suggesting a local resistance of the ground to penetration of >4 megapascals, equivalent to >2 megapascal uniaxial compressive strength". Here we assume that elastic properties of comet's nuclei could be similar to elastic properties of dry snow, namely Young modulus is assumed to be 1 - 100 MPa, see [3] and [4]. We consider nucleus of the shape of 67P/Churyumov-Gerasimenko with density 470 kg/m3. The impact or tidal forces result in changing of rotation of the comet. In general, the vector of angular velocity will be a subject to nutation that results in changing of centrifugal force, and consequently could be a factor triggering landslides. Note that nucleus' shape does not resemble the shape of surface of constant value of gravitational potential (i.e. 'geoid'). Our numerical models indicate the parts of the nucleus where landslides start and other parts where landslides stop. Of course, the regolith from the first type of regions would be removed to the regions of the second class. The motion of the mass is often complicated because of complicated distribution of the gravity and complicated shape of the nucleus. Acknowledgement: The research is partly supported by Polish National Science Centre

  4. Large contribution of virtual Delbrueck scattering to the emission of photons by relativistic nuclei in nucleus-nucleus and electron-nucleus collisions

    OpenAIRE

    Ginzburg, I. F.; Jentschura, U. D.; Serbo, V G

    2007-01-01

    Delbrueck scattering is an elastic scattering of a photon in the Coulomb field of a nucleus via a virtual electron loop. The contribution of this virtual subprocess to the emission of a photon in the collision of ultra-relativistic nuclei Z_1 Z_2 -> Z_1 Z_2 gamma is considered. We identify the incoming virtual photon as being generated by one of the relativistic nuclei involved in the binary collision and the scattered photon as being emitted in the process. The energy and angular distributio...

  5. Porous Shape Memory Polymers

    Science.gov (United States)

    Hearon, Keith; Singhal, Pooja; Horn, John; Small, Ward; Olsovsky, Cory; Maitland, Kristen C.; Wilson, Thomas S.; Maitland, Duncan J.

    2013-01-01

    Porous shape memory polymers (SMPs) include foams, scaffolds, meshes, and other polymeric substrates that possess porous three-dimensional macrostructures. Porous SMPs exhibit active structural and volumetric transformations and have driven investigations in fields ranging from biomedical engineering to aerospace engineering to the clothing industry. The present review article examines recent developments in porous SMPs, with focus given to structural and chemical classification, methods of characterization, and applications. We conclude that the current body of literature presents porous SMPs as highly interesting smart materials with potential for industrial use. PMID:23646038

  6. Oriented active shape models.

    Science.gov (United States)

    Liu, Jiamin; Udupa, Jayaram K

    2009-04-01

    Active shape models (ASM) are widely employed for recognizing anatomic structures and for delineating them in medical images. In this paper, a novel strategy called oriented active shape models (OASM) is presented in an attempt to overcome the following five limitations of ASM: 1) lower delineation accuracy, 2) the requirement of a large number of landmarks, 3) sensitivity to search range, 4) sensitivity to initialization, and 5) inability to fully exploit the specific information present in the given image to be segmented. OASM effectively combines the rich statistical shape information embodied in ASM with the boundary orientedness property and the globally optimal delineation capability of the live wire methodology of boundary segmentation. The latter characteristics allow live wire to effectively separate an object boundary from other nonobject boundaries with similar properties especially when they come very close in the image domain. The approach leads to a two-level dynamic programming method, wherein the first level corresponds to boundary recognition and the second level corresponds to boundary delineation, and to an effective automatic initialization method. The method outputs a globally optimal boundary that agrees with the shape model if the recognition step is successful in bringing the model close to the boundary in the image. Extensive evaluation experiments have been conducted by utilizing 40 image (magnetic resonance and computed tomography) data sets in each of five different application areas for segmenting breast, liver, bones of the foot, and cervical vertebrae of the spine. Comparisons are made between OASM and ASM based on precision, accuracy, and efficiency of segmentation. Accuracy is assessed using both region-based false positive and false negative measures and boundary-based distance measures. The results indicate the following: 1) The accuracy of segmentation via OASM is considerably better than that of ASM; 2) The number of landmarks

  7. Pairwise harmonics for shape analysis

    KAUST Repository

    Zheng, Youyi

    2013-07-01

    This paper introduces a simple yet effective shape analysis mechanism for geometry processing. Unlike traditional shape analysis techniques which compute descriptors per surface point up to certain neighborhoods, we introduce a shape analysis framework in which the descriptors are based on pairs of surface points. Such a pairwise analysis approach leads to a new class of shape descriptors that are more global, discriminative, and can effectively capture the variations in the underlying geometry. Specifically, we introduce new shape descriptors based on the isocurves of harmonic functions whose global maximum and minimum occur at the point pair. We show that these shape descriptors can infer shape structures and consistently lead to simpler and more efficient algorithms than the state-of-the-art methods for three applications: intrinsic reflectional symmetry axis computation, matching shape extremities, and simultaneous surface segmentation and skeletonization. © 2012 IEEE.

  8. Mast Wake Reduction by Shaping

    National Research Council Canada - National Science Library

    Beauchamp, Charles H

    2005-01-01

    The present invention relates to various mast shapes, in which the mast shapes minimize the production of visible, electro-optic, infrared and radar cross section wake signatures produced by water surface piercing masts...

  9. 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 ...

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

    Lifescience Database Archive (English)

    Full Text Available His.Neu.10.AllAg.Caudate_Nucleus hg19 Histone Neural Caudate Nucleus SRX998285,SRX9...98283 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Neu.10.AllAg.Caudate_Nucleus.bed ...

  11. File list: His.Neu.05.AllAg.Caudate_Nucleus [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Neu.05.AllAg.Caudate_Nucleus hg19 Histone Neural Caudate Nucleus SRX998283,SRX9...98285 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Neu.05.AllAg.Caudate_Nucleus.bed ...

  12. File list: ALL.Neu.20.AllAg.Caudate_Nucleus [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Neu.20.AllAg.Caudate_Nucleus hg19 All antigens Neural Caudate Nucleus SRX998285...,SRX998283 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/ALL.Neu.20.AllAg.Caudate_Nucleus.bed ...

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

    Lifescience Database Archive (English)

    Full Text Available ALL.Neu.50.AllAg.Caudate_Nucleus hg19 All antigens Neural Caudate Nucleus SRX998285...,SRX998283 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/ALL.Neu.50.AllAg.Caudate_Nucleus.bed ...

  14. File list: ALL.Neu.10.AllAg.Caudate_Nucleus [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Neu.10.AllAg.Caudate_Nucleus hg19 All antigens Neural Caudate Nucleus SRX998285...,SRX998283 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/ALL.Neu.10.AllAg.Caudate_Nucleus.bed ...

  15. 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 ...

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

    Lifescience Database Archive (English)

    Full Text Available ALL.Neu.05.AllAg.Caudate_Nucleus hg19 All antigens Neural Caudate Nucleus SRX998283...,SRX998285 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/ALL.Neu.05.AllAg.Caudate_Nucleus.bed ...

  17. Cellular Neurophysiology of the Rat Suprachiasmatic Nucleus: Electrical Properties, Neurotransmission, and Mechanisms of Synchronization

    Science.gov (United States)

    1994-07-29

    available concerning the important role of the suprachi- asmatic nucleus (SCN) in the generation of circadian rhythms (Klein et al., 1991), very little is...neurons are schematicized in terms of their numbers of asmatic nucleus; SDN, sexually dimorphic nucleus of the preoptic area; primary dendrites. ac

  18. Symmetry energy of the nucleus in the relativistic Thomas–Fermi ...

    Indian Academy of Sciences (India)

    The symmetry energy of a nucleus is determined in a local density approximation and integrating over the entire density distribution of the nucleus, calculated utilizing the relativistic density-dependent Thomas-Fermiapproach. The symmetry energy is found to decrease with increasing neutron excess in the nucleus.

  19. Issues in Biological Shape Modelling

    DEFF Research Database (Denmark)

    Hilger, Klaus Baggesen

    This talk reflects parts of the current research at informatics and Mathematical Modelling at the Technical University of Denmark within biological shape modelling. We illustrate a series of generalizations, modifications, and applications of the elements of constructing models of shape or appear......This talk reflects parts of the current research at informatics and Mathematical Modelling at the Technical University of Denmark within biological shape modelling. We illustrate a series of generalizations, modifications, and applications of the elements of constructing models of shape...

  20. Response properties of single units in the dorsal nucleus of the lateral lemniscus of decerebrate cats.

    Science.gov (United States)

    Davis, Kevin A; Lomakin, Oleg; Pesavento, Michael J

    2007-09-01

    The dorsal nucleus of the lateral lemniscus (DNLL) receives afferent inputs from many brain stem nuclei and, in turn, is a major source of inhibitory inputs to the inferior colliculus (IC). The goal of this study was to characterize the monaural and binaural response properties of neurons in the DNLL of unanesthetized decerebrate cat. Monaural responses were classified according to the patterns of excitation and inhibition observed in contralateral and ipsilateral frequency response maps. Binaural classification was based on unit sensitivity to interaural level differences. The results show that units in the DNLL can be grouped into three distinct types. Type v units produce contralateral response maps that show a wide V-shaped excitatory area and no inhibition. These units receive ipsilateral excitation and exhibit binaural facilitation. The contralateral maps of type i units show a more restricted I-shaped region of excitation that is flanked by inhibition. Type o maps display an O-shaped island of excitation at low stimulus levels that is bounded by inhibition at higher levels. Both type i and type o units receive ipsilateral inhibition and exhibit binaural inhibition. Units that produce type v maps have a low best frequency (BF), whereas type i and type o units have high BFs. Type v and type i units give monotonic rate-level responses for both BF tones and broadband noise. Type o units are inhibited by tones at high levels, but are excited by high-level noise. These results show that the DNLL can exert strong, differential effects in the IC.

  1. Gamma-ray spectroscopy of the nucleus {sup 139}Ce

    Energy Technology Data Exchange (ETDEWEB)

    Bucurescu, D.; Cata-Danil, G.; Cata-Danil, I.; Ivascu, M.; Marginean, N.; Marginean, R.; Mihailescu, L.C.; Rusu, C.; Suliman, G. [Horia Hulubei National Institute of Physics and Nuclear Engineering, P.O. Box MG-6, Bucharest (Romania)

    2006-03-15

    Gamma-ray coincidence techniques are used to determine new level structures in the N=81 nucleus {sup 139}Ce, at low spins and excitation energies with the {sup 139}La(p,n{gamma}) reaction at 5.0 and 6.0 MeV incident energy, and at high spins with the {sup 130}Te({sup 12}C,3n{gamma}) reaction at 50.5 MeV, respectively. Lifetime determinations are also made in the (p,n{gamma}) reaction with the centroid DSA method. The observed level structures are discussed by comparison with existing calculations and with those in the neighbouring nucleus {sup 140}Ce. (orig.)

  2. From Nucleons to Nucleus Concepts of Microscopic Nuclear Theory

    CERN Document Server

    Suhonen, Jouni

    2007-01-01

    From Nucleons to Nucleus deals with single-particle and collective features of spherical nuclei. Each nuclear model is introduced and derived in detail. The formalism is then applied to light and medium-heavy nuclei in worked-out examples, and finally the acquired skills are strengthened by a wide selection of exercises, many relating the models to experimental data. Nuclear properties are discussed using particles, holes and quasiparticles. A large number of matrix elements of standard operators have been tabulated for reference. From Nucleons to Nucleus is based on lectures on nuclear physics given by the author. Its main scope is thus to serve as a textbook for advanced students. But also researchers will appreciate it as wellbalanced reference to theoretical nuclear physics.

  3. Experiments on parity violation in the compound nucleus

    Energy Technology Data Exchange (ETDEWEB)

    Bowman, J.D.

    1996-09-01

    Results from experiments that measure parity-violating longitudinal asymmetries in the scattering of epithermal neutrons from compound-nuclear resonances at the Manuel Lujan Neutron Scattering Center at Los Alamos are discussed. Parity non-conserving asymmetries have been observed for many p-wave resonances in a single target. Measurements were performed on several nuclei in the mass region of A-100 and A-230. The statistical model of the compound nucleus provides a theoretical basis for extracting mean-squared matrix elements from the experimental asymmetry data, and for interpreting the mean-squared matrix elements. The constraints on the weak meson-exchange couplings calculated from the compound-nucleus asymmetry data agree qualitatively with the results from few-body and light-nuclei experiments. For all nuclei but {sup 232}Th measured asymmetries have random signs. For {sup 232}Th eight of eight measured asymmetries are positive. This phenomenon is discussed in terms or doorway models.

  4. The abducens nucleus in the carpet shark Cephaloscyllium isabella.

    Science.gov (United States)

    Montgomery, J C; Housley, G D

    1983-12-01

    This study utilizes retrograde axonal transport of cobaltous-lysine, and conventional silver and Golgi staining techniques to study the abducens motor nucleus innervating the external rectus muscle of the carpet shark. The nucleus consists of 300-400 motoneurons located immediately ventrolateral to the medial longitudinal fasciculus (MLF), distributed over about 1.25 mm in a rostrocaudal direction at the level of exit of the VI nerve. The axons of the motoneurons form seven or eight discrete ventrally directed fascicles which, having exited from the brainstem, group together to form the abducens (VI) nerve. The motoneurons are on average about 16 micron in diameter, are bipolar, and their dendrites have a transverse orientation. Typically one set of dendrites penetrates the MLF and the other set extends ventrally into the reticular formation.

  5. The cellular mastermind(?) – Mechanotransduction and the nucleus

    Science.gov (United States)

    Kaminski, Ashley; Fedorchak, Gregory R.; Lammerding, Jan

    2015-01-01

    Cells respond to mechanical stimulation by activation of specific signaling pathways and genes that allow the cell to adapt to its dynamic physical environment. How cells sense the various mechanical inputs and translate them into biochemical signals remains an area of active investigation. Recent reports suggest that the cell nucleus may be directly implicated in this cellular mechanotransduction process. In this chapter, we discuss how forces applied to the cell surface and cytoplasm induce changes in nuclear structure and organization, which could directly affect gene expression, while also highlighting the complex interplay between nuclear structural proteins and transcriptional regulators that may further modulate mechanotransduction signaling. Taken together, these findings paint a picture of the nucleus as a central hub in cellular mechanotransduction—both structurally and biochemically—with important implications in physiology and disease. PMID:25081618

  6. Epilepsy, electroacupuncture and the nucleus of the solitary tract.

    Science.gov (United States)

    Cakmak, Yusuf Ozgur

    2006-12-01

    Vagal nerve stimulation and electroacupuncture have some promise as neuroprotective therapies for patients with poorly controlled epilepsy. It has been demonstrated that stimulation of acupuncture points on the extremities results in stimulation of the vagus nerve. It is possible that the antiepileptic effects of these two applications might be targeting the same centre in the brain. The nucleus of the solitary tract, which is a primary site at which vagal afferents terminate, is also the site for afferent pathways of facial, scalp and auricular acupuncture via trigeminal, cervical spinal and glossopharyngeal nerves. Taken together with laboratory findings, the neuroprotective pathways of electroacupuncture in epileptic models may stem from the collaboration of its anti-inflammatory and neurotrophic actions through the nucleus of the solitary tract via vagus nerve stimulation.

  7. 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.

  8. QCD evolution of the gluon density in a nucleus

    Energy Technology Data Exchange (ETDEWEB)

    Ayala Filho, A.L. [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Inst. de Fisica]|[Universidade Federal de Pelotas, RS (Brazil). Inst. de Fisica e Matematica; Ducati, M.B. Gay [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Inst. de Fisica; Levin, E.M. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil)]|[Petersburg Nuclear Physics Inst., St. Petersburg (Russian Federation). Theory Dept.

    1996-04-01

    The Glauber approach to the gluon density in a nucleus, suggested by A. Mueller, is developed and studied in detail. Using the GRV parameterization for the gluon density in a nucleon, the value as well as energy and Q{sup 2} dependence of the gluon density in a nucleus is calculated. It is shown that the shadowing corrections are under theoretical control and are essential in the region of small x. The change crucially the value of the gluon density as well as the value of the anomalous dimension of the nuclear structure function, unlike of the nucleon one. The systematic theoretical way to treat the correction to the Glauber approach is developed and a new evolution equation is derived and solved. It is shown that the solution of the new evolution equation can provide a self consistent matching of `soft` high energy phenomenology with `hard` QCD physics. (author). 51 refs., 25 figs., 1 tab.

  9. The Suprachiasmatic Nucleus of the Dromedary Camel (Camelus dromedarius: Cytoarchitecture and Neurochemical Anatomy

    Directory of Open Access Journals (Sweden)

    Khalid El Allali

    2017-11-01

    Full Text Available In mammals, biological rhythms are driven by a master circadian clock located in the suprachiasmatic nucleus (SCN of the hypothalamus. Recently, we have demonstrated that in the camel, the daily cycle of environmental temperature is able to entrain the master clock. This raises several questions about the structure and function of the SCN in this species. The current work is the first neuroanatomical investigation of the camel SCN. We carried out a cartography and cytoarchitectural study of the nucleus and then studied its cell types and chemical neuroanatomy. Relevant neuropeptides involved in the circadian system were investigated, including arginine-vasopressin (AVP, vasoactive intestinal polypeptide (VIP, met-enkephalin (Met-Enk, neuropeptide Y (NPY, as well as oxytocin (OT. The neurotransmitter serotonin (5-HT and the enzymes tyrosine hydroxylase (TH and aromatic L-amino acid decarboxylase (AADC were also studied. The camel SCN is a large and elongated nucleus, extending rostrocaudally for 9.55 ± 0.10 mm. Based on histological and immunofluorescence findings, we subdivided the camel SCN into rostral/preoptic (rSCN, middle/main body (mSCN and caudal/retrochiasmatic (cSCN divisions. Among mammals, the rSCN is unusual and appears as an assembly of neurons that protrudes from the main mass of the hypothalamus. The mSCN exhibits the triangular shape described in rodents, while the cSCN is located in the retrochiasmatic area. As expected, VIP-immunoreactive (ir neurons were observed in the ventral part of mSCN. AVP-ir neurons were located in the rSCN and mSCN. Results also showed the presence of OT-ir and TH-ir neurons which seem to be a peculiarity of the camel SCN. OT-ir neurons were either scattered or gathered in one isolated cluster, while TH-ir neurons constituted two defined populations, dorsal parvicellular and ventral magnocellular neurons, respectively. TH colocalized with VIP in some rSCN neurons. Moreover, a high density of Met

  10. Hidden Glashow resonance in neutrino–nucleus collisions

    Directory of Open Access Journals (Sweden)

    I. Alikhanov

    2016-05-01

    Full Text Available Today it is widely believed that s-channel excitation of an on-shell W boson, commonly known as the Glashow resonance, can be initiated in matter only by the electron antineutrino in the process ν¯ee−→W− at the laboratory energy around 6.3 PeV. In this Letter we argue that the Glashow resonance within the Standard Model also occurs in neutrino–nucleus collisions. The main conclusions are as follows. 1 The Glashow resonance can be excited by both neutrinos and antineutrinos of all the three flavors scattering in the Coulomb field of a nucleus. 2 The Glashow resonance in a neutrino–nucleus reaction does not manifest itself as a Breit–Wigner-like peak in the cross section but the latter exhibits instead a slow logarithmic-law growth with the neutrino energy. The resonance turns thus out to be hidden. 3 More than 98% of W bosons produced in the sub-PeV region in neutrino-initiated reactions in water/ice will be from the Glashow resonance. 4 The vast majority of the Glashow resonance events in a neutrino detector are expected at energies from a few TeV to a few tens of TeV, being mostly initiated by the conventional atmospheric neutrinos dominant in this energy range. Calculations of the cross sections for Glashow resonance excitation on the oxygen nucleus as well as on the proton are carried out in detail. The results of this Letter can be useful for studies of neutrino interactions at large volume water/ice neutrino detectors. For example, in the IceCube detector one can expect 0.3 Glashow resonance events with shower-like topologies and the deposited energies above 300 TeV per year. It is therefore likely already to have at least one Glashow resonance event in the IceCube data set.

  11. mRNA-Producing Pseudo-nucleus System.

    Science.gov (United States)

    Shin, Seung Won; Park, Kyung Soo; Shin, Woo Jung; Um, Soong Ho

    2015-11-04

    A pseudo-eukaryotic nucleus (PEN) system consisting of a gene-containing DNA hydrogel encapsulated in a liposome is fabricated. Owing to the structural characteristics of gene-containing DNA hydrogel, mRNA transcription efficiency is promoted 2.57-fold. Through the use of PEN as a platform for mRNA delivery to the cytosol, prolonged protein translation is achieved. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Magnetic rotation in the nucleus 141Eu

    Energy Technology Data Exchange (ETDEWEB)

    Marcinkowska, Z.; Rzaca-Urban, T.; Droste, C.; Morek, T.; Czajkowska, B.; Urban, W.; Marcinkowski, R.; Olbratowski, P.; Lieder, R. M.; Brans, H.; Gast, W.; Jager, H. M.; Mihailescu, L.; Bazzacco, D.; Falconi, G.; Menegazzo, R.; Lunardi, S.; Rossi-Alvarez, C.; De Angelis, G.; Farnea, E.; Gadea, A.; Napoli, D. R.; Podolyak, Z.

    2003-04-01

    The previously known level scheme of 141 Eu nucleus was revised and substantially extended. Three dipole cascades, characterized by large B(M1)/B(E2) ratios, have been found. Spin and parity assignments were based on the angular distribution ratios and linear polarizations of γ-rays. The experimental results have been compared with the calculations of Tilted Axis Cranking (TAC) model.

  13. Depolarizing Actions of Hydrogen Sulfide on Hypothalamic Paraventricular Nucleus Neurons

    OpenAIRE

    C Sahara Khademullah; Ferguson, Alastair V.

    2013-01-01

    Hydrogen sulfide (H2S) is a novel neurotransmitter that has been shown to influence cardiovascular functions as well and corticotrophin hormone (CRH) secretion. Since the paraventricular nucleus of the hypothalamus (PVN) is a central relay center for autonomic and endocrine functions, we sought to investigate the effects of H2S on the neuronal population of the PVN. Whole cell current clamp recordings were acquired from the PVN neurons and sodium hydrosulfide hydrate (NaHS) was bath applied a...

  14. Isospin symmetry violation, meson production and η-nucleus ...

    Indian Academy of Sciences (India)

    nucleus interaction is the behaviour of N∗(1535) resonance in nuclear matter. Due to the large mass of η-meson (547 MeV), this S11 resonance is very close to η-N threshold. The resonance is also very broad with Γ ∼ 150 MeV covering the whole low energy region of η-nucleon interaction. The η-nucleon interaction at low ...

  15. Integration of sensory quanta in cuneate nucleus neurons in vivo.

    Directory of Open Access Journals (Sweden)

    Fredrik Bengtsson

    Full Text Available Discriminative touch relies on afferent information carried to the central nervous system by action potentials (spikes in ensembles of primary afferents bundled in peripheral nerves. These sensory quanta are first processed by the cuneate nucleus before the afferent information is transmitted to brain networks serving specific perceptual and sensorimotor functions. Here we report data on the integration of primary afferent synaptic inputs obtained with in vivo whole cell patch clamp recordings from the neurons of this nucleus. We find that the synaptic integration in individual cuneate neurons is dominated by 4-8 primary afferent inputs with large synaptic weights. In a simulation we show that the arrangement with a low number of primary afferent inputs can maximize transfer over the cuneate nucleus of information encoded in the spatiotemporal patterns of spikes generated when a human fingertip contact objects. Hence, the observed distributions of synaptic weights support high fidelity transfer of signals from ensembles of tactile afferents. Various anatomical estimates suggest that a cuneate neuron may receive hundreds of primary afferents rather than 4-8. Therefore, we discuss the possibility that adaptation of synaptic weight distribution, possibly involving silent synapses, may function to maximize information transfer in somatosensory pathways.

  16. The Nuclear Option: Evidence Implicating the Cell Nucleus in Mechanotransduction.

    Science.gov (United States)

    Szczesny, Spencer E; Mauck, Robert L

    2017-02-01

    Biophysical stimuli presented to cells via microenvironmental properties (e.g., alignment and stiffness) or external forces have a significant impact on cell function and behavior. Recently, the cell nucleus has been identified as a mechanosensitive organelle that contributes to the perception and response to mechanical stimuli. However, the specific mechanotransduction mechanisms that mediate these effects have not been clearly established. Here, we offer a comprehensive review of the evidence supporting (and refuting) three hypothetical nuclear mechanotransduction mechanisms: physical reorganization of chromatin, signaling at the nuclear envelope, and altered cytoskeletal structure/tension due to nuclear remodeling. Our goal is to provide a reference detailing the progress that has been made and the areas that still require investigation regarding the role of nuclear mechanotransduction in cell biology. Additionally, we will briefly discuss the role that mathematical models of cell mechanics can play in testing these hypotheses and in elucidating how biophysical stimulation of the nucleus drives changes in cell behavior. While force-induced alterations in signaling pathways involving lamina-associated polypeptides (LAPs) (e.g., emerin and histone deacetylase 3 (HDAC3)) and transcription factors (TFs) located at the nuclear envelope currently appear to be the most clearly supported mechanism of nuclear mechanotransduction, additional work is required to examine this process in detail and to more fully test alternative mechanisms. The combination of sophisticated experimental techniques and advanced mathematical models is necessary to enhance our understanding of the role of the nucleus in the mechanotransduction processes driving numerous critical cell functions.

  17. Ground control to major TOM: mitochondria-nucleus communication.

    Science.gov (United States)

    Eisenberg-Bord, Michal; Schuldiner, Maya

    2017-01-01

    Mitochondria have crucial functions in the cell, including ATP generation, iron-sulfur cluster biogenesis, nucleotide biosynthesis, and amino acid metabolism. All of these functions require tight regulation on mitochondrial activity and homeostasis. As mitochondria biogenesis is controlled by the nucleus and almost all mitochondrial proteins are encoded by nuclear genes, a tight communication network between mitochondria and the nucleus has evolved, which includes signaling cascades, proteins which are dual-localized to the two compartments, and sensing of mitochondrial products by nuclear proteins. All of these enable a crosstalk between mitochondria and the nucleus that allows the 'ground control' to get information on mitochondria's status. Such information facilitates the creation of a cellular balance of mitochondrial status with energetic needs. This communication also allows a transcriptional response in case mitochondrial function is impaired aimed to restore mitochondrial homeostasis. As mitochondrial dysfunction is related to a growing number of genetic diseases as well as neurodegenerative conditions and aging, elucidating the mechanisms governing the mitochondrial/nuclear communication should progress a better understanding of mitochondrial dysfunctions. © 2016 Federation of European Biochemical Societies.

  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. Experimental studies of pion-nucleus interactions at intermediate energies

    Energy Technology Data Exchange (ETDEWEB)

    1991-12-31

    This report summarizes the work on experimental research in intermediate energy nuclear physics carried out at New Mexico State University in 1991 under a great from the US Department of Energy. Most of these studies have involved investigations of various pion-nucleus interactions. The work has been carried out both with the LAMPF accelerator at the Los Alamos National Laboratory and with the cyclotron at the Paul Scherrer Institute (PSI) near Zurich, Switzerland. Part of the experimental work involves measurements of new data on double-charge-exchange scattering, using facilities at LAMPF which we helped modify, and on pion absorption, using a new detector system at PSI that covers nearly the full solid-angle region which we helped construct. Other work involved preparation for future experiments using polarized nuclear targets and a new high-resolution spectrometer system for detecting {pi}{sup 0} mesons. We also presented several proposals for works to be done in future years, involving studies related to pi-mesonic atoms, fundamental pion-nucleon interactions, studies of the difference between charged and neutral pion interactions with the nucleon, studies of the isospin structure of pion-nucleus interactions, and pion scattering from polarized {sup 3}He targets. This work is aimed at improving our understanding of the pion-nucleon interaction, of the pion-nucleus interaction mechanism, and of nuclear structure.

  20. Projections from the subdivisions of the fastigial nucleus to the vestibular complex and the prepositus hypoglossal nucleus in the albino rat: an anterograde tracing study using biocytin.

    Science.gov (United States)

    Omori, O; Umetani, T; Sugioka, K

    1997-02-01

    Differential projections from the subdivisions of the fastigial nucleus to the vestibular complex and the prepositus hypoglossal nucleus were investigated by an anterograde tracing method using biocytin in the albino rat. The caudomedial subdivision of the nucleus projected ipsilaterally to the dorsal and medial parts of the superior vestibular nucleus (Su Ve), the dorsomedial part of the lateral vestibular nucleus (LVe), and the dorsal parts of the medial (MVe) and spinal (Sp Ve) vestibular nuclei, and projected contralaterally to the ventrolateral corners of the Su Ve and LVe, the ventral part of the MVe, and the lateral part of the Sp Ve. The bilateral prepositus hypoglossal nuclei received sparse projections from the caudomedial subdivision. The middle subdivision of the fastigial nucleus projected ipsilaterally to the dorsal and/or ventral parts of the Su Ve, the dorsomedial pats of the LVe and Sp Ve, and the dorsolateral part of the MVe, and projected contralaterally to the dorsal margin of the Su Ve, the ventrolateral part of the LVe, and the lateral part of the Sp Ve. The dorsolateral protuberance of the fastigial nucleus projected ipsilaterally to the dorsal margin of the Su Ve, the dorsomedial part of the LVe, the dorsal or lateral parts of the Sp Ve, and the lateral part of the MVe, and projected contralaterally to the ventrolateral part of the LVe and the lateral part of the Sp Ve. The subnuclei x, y, and f, interstitial nucleus of the vestibular nerve, and the infracerebellar nucleus received bilateral or ipsilateral fastigiovestibular projections.

  1. Cytoskeletal influences on nuclear shape in granulocytic HL-60 cells.

    Science.gov (United States)

    Olins, Ada L; Olins, Donald E

    2004-08-19

    During granulopoiesis in the bone marrow, the nucleus differentiates from ovoid to lobulated shape. Addition of retinoic acid (RA) to leukemic HL-60 cells induces development of lobulated nuclei, furnishing a convenient model system for nuclear differentiation during granulopoiesis. Previous studies from our laboratory have implicated nuclear envelope composition as playing important roles in nuclear shape changes. Specifically noted were: 1) a paucity of lamins A/C and B1 in the undifferentiated and RA treated cell forms; 2) an elevation of lamin B receptor (LBR) during induced granulopoiesis. The present study demonstrates that perturbation of cytoskeletal elements influences nuclear differentiation of HL-60 cells. Because of cytotoxicity from prolonged exposure to cytoskeleton-modifying drugs, most studies were performed with a Bcl-2 overexpressing HL-60 subline. We have found that: 1) nocodazole prevents RA induction of lobulation; 2) taxol induces lobulation and micronuclear formation, even in the absence of RA; 3) cytochalasin D does not inhibit RA induced nuclear lobulation, and prolonged exposure induces nuclear shape changes in the absence of RA. The present results, in the context of earlier data and models, suggest a mechanism for granulocytic nuclear lobulation. Our current hypothesis is that the nuclear shape change involves factors that increase the flexibility of the nuclear envelope (reduced lamin content), augment connections to the underlying heterochromatin (increased levels of LBR) and promote distortions imposed by the cytoskeleton (microtubule motors creating tension in the nuclear envelope).

  2. Cytoskeletal influences on nuclear shape in granulocytic HL-60 cells

    Directory of Open Access Journals (Sweden)

    Olins Donald E

    2004-08-01

    Full Text Available Abstract Background During granulopoiesis in the bone marrow, the nucleus differentiates from ovoid to lobulated shape. Addition of retinoic acid (RA to leukemic HL-60 cells induces development of lobulated nuclei, furnishing a convenient model system for nuclear differentiation during granulopoiesis. Previous studies from our laboratory have implicated nuclear envelope composition as playing important roles in nuclear shape changes. Specifically noted were: 1 a paucity of lamins A/C and B1 in the undifferentiated and RA treated cell forms; 2 an elevation of lamin B receptor (LBR during induced granulopoiesis. Results The present study demonstrates that perturbation of cytoskeletal elements influences nuclear differentiation of HL-60 cells. Because of cytotoxicity from prolonged exposure to cytoskeleton-modifying drugs, most studies were performed with a Bcl-2 overexpressing HL-60 subline. We have found that: 1 nocodazole prevents RA induction of lobulation; 2 taxol induces lobulation and micronuclear formation, even in the absence of RA; 3 cytochalasin D does not inhibit RA induced nuclear lobulation, and prolonged exposure induces nuclear shape changes in the absence of RA. Conclusions The present results, in the context of earlier data and models, suggest a mechanism for granulocytic nuclear lobulation. Our current hypothesis is that the nuclear shape change involves factors that increase the flexibility of the nuclear envelope (reduced lamin content, augment connections to the underlying heterochromatin (increased levels of LBR and promote distortions imposed by the cytoskeleton (microtubule motors creating tension in the nuclear envelope.

  3. Zeptosecond precision pulse shaping.

    Science.gov (United States)

    Köhler, Jens; Wollenhaupt, Matthias; Bayer, Tim; Sarpe, Cristian; Baumert, Thomas

    2011-06-06

    We investigate the temporal precision in the generation of ultrashort laser pulse pairs by pulse shaping techniques. To this end, we combine a femtosecond polarization pulse shaper with a polarizer and employ two linear spectral phase masks to mimic an ultrastable common-path interferometer. In an all-optical experiment we study the interference signal resulting from two temporally delayed pulses. Our results show a 2σ-precision of 300 zs = 300 × 10(-21) s in pulse-to-pulse delay. The standard deviation of the mean is 11 zs. The obtained precision corresponds to a variation of the arm's length in conventional delay stage based interferometers of 0.45 Å. We apply these precisely generated pulse pairs to a strong-field quantum control experiment. Coherent control of ultrafast electron dynamics via photon locking by temporal phase discontinuities on a few attosecond timescale is demonstrated.

  4. Shaping 3-D boxes

    DEFF Research Database (Denmark)

    Stenholt, Rasmus; Madsen, Claus B.

    2011-01-01

    Enabling users to shape 3-D boxes in immersive virtual environments is a non-trivial problem. In this paper, a new family of techniques for creating rectangular boxes of arbitrary position, orientation, and size is presented and evaluated. These new techniques are based solely on position data......F) docking experiment against an existing technique, which requires the user to perform the rotation and scaling of the box explicitly. The precision of the users' box construction is evaluated by a novel error metric measuring the difference between two boxes. The results of the experiment strongly indicate...... that for precision docking of 9 DoF boxes, some of the proposed techniques are significantly better than ones with explicit rotation and scaling. Another interesting result is that the number of DoF simultaneously controlled by the user significantly influences the precision of the docking....

  5. Magnetic Shape Memory Microactuators

    Directory of Open Access Journals (Sweden)

    Manfred Kohl

    2014-11-01

    Full Text Available By introducing smart materials in micro systems technologies, novel smart microactuators and sensors are currently being developed, e.g., for mobile, wearable, and implantable MEMS (Micro-electro-mechanical-system devices. Magnetic shape memory alloys (MSMAs are a promising material system as they show multiple coupling effects as well as large, abrupt changes in their physical properties, e.g., of strain and magnetization, due to a first order phase transformation. For the development of MSMA microactuators, considerable efforts are undertaken to fabricate MSMA foils and films showing similar and just as strong effects compared to their bulk counterparts. Novel MEMS-compatible technologies are being developed to enable their micromachining and integration. This review gives an overview of material properties, engineering issues and fabrication technologies. Selected demonstrators are presented illustrating the wide application potential.

  6. A transport set-up for heavy-flavour observables in nucleus-nucleus collisions at RHIC and LHC

    CERN Document Server

    Nardi, Marzia; Beraudo, A; De Pace, A; Molinari, A; Monteno, M; Prino, F; Sitta, M

    2014-01-01

    A multi-step setup for heavy-flavour studies in high-energy nucleus–nucleus collisions is presented. The initial hard production of View the MathML sourceQ$\\bar{Q}$ pairs is simulated with the POWHEG pQCD event generator, interfaced with the PYTHIA parton shower. In a nucleus–nucleus collision the propagation of the heavy quarks in the medium is described through the relativistic Langevin equation. The numerical results are compared to experimental data from the RHIC and the LHC. In particular we show the comparisons of the nuclear modification factor of D-mesons, non-prompt J/ψJ/ψ's and heavy-flavour electrons. Furthermore, first results on azimuthal correlations of heavy quark pair and open charm/beauty meson pairs are presented.

  7. Dielectron Cross Section Measurements in Nucleus-Nucleus Reactions at 1.0{ital A} GeV

    Energy Technology Data Exchange (ETDEWEB)

    Porter, R.J.; Bossingham, R.; Gong, W.G.; Heilbronn, L.; Huang, H.Z.; Krebs, G.; Letessier-Selvon, A.; Matis, H.S.; Miller, J.; Naudet, C.; Roche, G.; Schroeder, L.S.; Seidl, P.; Wilson, W.K.; Yegneswaran, A. [Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720 (United States); Beedoe, S.; Carroll, J.; Huang, H.Z.; Igo, G. [University of California at Los Angeles, California 90095 (United States); Bougteb, M.; Manso, F.; Prunet, M.; Roche, G. [Universite Blaise Pascal/IN2P3, 63177 Aubiere Cedex (France); Christie, W.B.; Hallman, T.; Madansky, L.; Welsh, R.C. [The Johns Hopkins University, Baltimore, Maryland 21218 (United States); Kirk, P.; Wang, Z.F. [Louisiana State University, Baton Rouge, Louisiana 70803 (United States); Wilson, W.K. [Wayne State University, Detroit, Michigan 48201 (United States)

    1997-08-01

    We present measured dielectron production cross sections for Ca+Ca, C+C, He+Ca, and d+Ca reactions at 1.0 A GeV . Statistical uncertainties and systematic effects are smaller than in previous dilepton spectrometer (DLS) nucleus-nucleus data. For pair mass M{le}0.35 GeV/c{sup 2} we obtain (1) the Ca+Ca cross section is larger than the previous DLS measurement and current model results, (2) the mass spectra suggest large contributions from {pi}{sup 0} and {eta} Dalitz decays, and (3) d{sigma}/dM{proportional_to}A{sub P}A{sub T}. For M{gt}0.5 GeV/c{sup 2} the Ca+Ca to C+C cross section ratio is significantly larger than the ratio of A{sub P}A{sub T} values. {copyright} {ital 1997} {ital The American Physical Society}

  8. Long noncoding RNAs coordinate functions between mitochondria and the nucleus.

    Science.gov (United States)

    Dong, Yaru; Yoshitomi, Takeshi; Hu, Ji-Fan; Cui, Jizhe

    2017-08-23

    In animal cells, mitochondria are the primary powerhouses and metabolic factories. They also contain genomes and can produce mitochondrial-specific nucleic acids and proteins. To maintain homeostasis of the entire cell, an intense cross-talk between mitochondria and the nucleus, mediated by encoded noncoding RNAs (ncRNAs), as well as proteins, is required. Long ncRNAs (lncRNAs) contain characteristic structures, and they are involved in the regulation of almost every stage of gene expression, as well as being implicated in a variety of disease states, such as cancer. In the coordinated signaling system, several lncRNAs, transcribed in the nucleus but residing in mitochondria, play a key role in regulating mitochondrial functions or dynamics. For example, RMRP, a component of the mitochondrial RNase MRP, is important for mitochondrial DNA replication and RNA processing, and the steroid receptor RNA activator, SRA, is a key modulator of hormone signaling and is present in both the nucleus and mitochondria. Some RNA-binding proteins maybe play a role in the lncRNAs transport system, such as HuR, GRSF1, SHARP, SLIRP, PPR, and PNPASE. Furthermore, a series of nuclear DNA-encoded lncRNAs were implicated in mitochondria-mediated apoptosis, mitochondrial bioenergetics and biosynthesis, and glutamine metabolism. The mitochondrial genome can also encode a set of lncRNAs, and they are divided into three categories: (1) lncND5, lncND6, and lncCyt b RNA; (2) chimeric mitochondrial DNA-encoded lncRNAs; and (3) putative mitochondrial DNA-encoded lncRNAs. It has been reported that the mitochondrial DNA-encoded lncRNAs appear to operate in the nucleus. The molecular mechanisms underlying trafficking of the mitochondrial DNA-encoded lncRNAs to the nucleus in mammals are only now beginning to emerge. In conclusion, both nuclear- and mitochondrial DNA-encoded lncRNAs mediate an intense intercompartmental cross-talk, which opens a rich field for investigation of the mechanism

  9. Nucleus-encoded periplastid-targeted EFL in chlorarachniophytes.

    Science.gov (United States)

    Gile, Gillian H; Keeling, Patrick J

    2008-09-01

    Chlorarachniophytes are cercozoan amoeboflagellates that acquired photosynthesis by enslaving a green alga, which has retained a highly reduced nucleus called a nucleomorph. The nucleomorph lacks many genes necessary for its own maintenance and expression, suggesting that some genes have been moved to the host nucleus and their products are now targeted back to the periplastid compartment (PPC), the reduced eukaryotic cytoplasm of the endosymbiont. Protein trafficking in chlorarachniophytes is therefore complex, including nucleus-encoded plastid-targeted proteins, nucleomorph-encoded plastid-targeted proteins, and nucleus-encoded periplastid-targeted proteins. A major gap in our understanding of this system is the PPC-targeted proteins because none have been described in any chlorarachniophytes. Here we describe the first such protein, the GTPase EFL. EFL was characterized from 7 chlorarachniophytes, and 2 distinct types were found. One is related to foraminiferan EFL and lacks an amino-terminal extension. The second, distantly related, type encodes an amino-terminal extension consisting of a signal peptide followed by sequence sharing many characteristics with transit peptides from nucleus-encoded plastid-targeted proteins and which we conclude is most likely PPC targeted. Western blotting with antibodies specific to putative host and PPC-targeted EFL from the chlorarachniophytes Bigelowiella natans and Gymnochlora stellata is consistent with posttranslational cleavage of the leaders from PPC-targeted proteins. Immunolocalization of both proteins in B. natans confirmed the cytosolic location of the leaderless EFL and a distinct localization pattern for the PPC-targeted protein but could not rule out a plastid location (albeit very unlikely). We sought other proteins with a similar leader and identified a eukaryotic translation initiation factor 1 encoding a bipartite extension with the same properties. Transit peptide sequences were characterized from all 3

  10. SHAPE Selection (SHAPES) enrich for RNA structure signal in SHAPE sequencing-based probing data

    Science.gov (United States)

    Poulsen, Line Dahl; Kielpinski, Lukasz Jan; Salama, Sofie R.; Krogh, Anders; Vinther, Jeppe

    2015-01-01

    Selective 2′ Hydroxyl Acylation analyzed by Primer Extension (SHAPE) is an accurate method for probing of RNA secondary structure. In existing SHAPE methods, the SHAPE probing signal is normalized to a no-reagent control to correct for the background caused by premature termination of the reverse transcriptase. Here, we introduce a SHAPE Selection (SHAPES) reagent, N-propanone isatoic anhydride (NPIA), which retains the ability of SHAPE reagents to accurately probe RNA structure, but also allows covalent coupling between the SHAPES reagent and a biotin molecule. We demonstrate that SHAPES-based selection of cDNA–RNA hybrids on streptavidin beads effectively removes the large majority of background signal present in SHAPE probing data and that sequencing-based SHAPES data contain the same amount of RNA structure data as regular sequencing-based SHAPE data obtained through normalization to a no-reagent control. Moreover, the selection efficiently enriches for probed RNAs, suggesting that the SHAPES strategy will be useful for applications with high-background and low-probing signal such as in vivo RNA structure probing. PMID:25805860

  11. Shape integral method for magnetospheric shapes. [boundary layer calculations

    Science.gov (United States)

    Michel, F. C.

    1979-01-01

    A method is developed for calculating the shape of any magnetopause to arbitrarily high precision. The method uses an integral equation which is evaluated for a trial shape. The resulting values of the integral equation as a function of auxiliary variables indicate how close one is to the desired solution. A variational method can then be used to improve the trial shape. Some potential applications are briefly mentioned.

  12. Nonparametric joint shape learning for customized shape modeling

    OpenAIRE

    Ünal, Gözde; Unal, Gozde

    2010-01-01

    We present a shape optimization approach to compute patient-specific models in customized prototyping applications. We design a coupled shape prior to model the transformation between a related pair of surfaces, using a nonparametric joint probability density estimation. The coupled shape prior forces with the help of application-specific data forces and smoothness forces drive a surface deformation towards a desired output surface. We demonstrate the usefulness of the method for generatin...

  13. Hearing preservation outcomes with different cochlear implant electrodes: Nucleus® Hybrid™-L24 and Nucleus Freedom™ CI422.

    Science.gov (United States)

    Jurawitz, Marie-Charlot; Büchner, Andreas; Harpel, Theo; Schüssler, Mark; Majdani, Omid; Lesinski-Schiedat, Anke; Lenarz, Thomas

    2014-01-01

    In recent years, it has been possible to preserve hearing after cochlear implantation in patients with significant amounts of low-frequency residual hearing. Due to the dimensions and characteristics of the cochlear implants (CIs) Nucleus® Hybrid™-L24 and Nucleus Freedom™ CI422, both can be used to preserve residual hearing. The aim was to investigate the degree and progression of hearing preservation over a longitudinal postoperative period in a large consecutive cohort of implanted patients with preoperative residual hearing who received either the Nucleus Hybrid-L24 or the Nucleus Freedom CI422 implant. The intention was to examine potential characteristics and triggers of resulting postoperative hearing loss which may support a differentiation of CI candidacy criteria for a certain implant type. A retrospective data analysis of patient files on consecutively implanted subjects presenting with a severe-to-profound sensorineural hearing loss at frequencies>1,500 Hz and substantial residual hearing at frequencies≤1,500 Hz, implanted with a Nucleus Hybrid-L24 (n=97) or a CI422 implant (n=100), was undertaken. A single-subject repeated-measure design comparing the mean threshold shift for pure-tone thresholds under headphones up to 24 months after implantation was used. Hearing preservation is observed in the majority of subjects with either implant (250-1,500 Hz frequency range). Hybrid-L24 patients exhibited a median hearing loss of 10 dB at initial fitting (n=97) and of 15 dB after 24 months (n=51). A 14.4-dB decrease in median hearing loss at initial fitting (n=100) and a 30-dB decrease after 24 months (n=28) was observed with the CI422 electrode. At initial fitting, 54.6% of the Hybrid-L24 (n=97) and 49.0% of the CI422 (n=100) subjects showed a mean threshold shifthearing was preserved for the majority of implanted patients with the Hybrid-L24 and the CI422 implant. Patients implanted with the Hybrid-L24 implant demonstrate greater stability and less

  14. Shape vocabulary: a robust and efficient shape representation for shape matching.

    Science.gov (United States)

    Bai, Xiang; Rao, Cong; Wang, Xinggang

    2014-09-01

    In this paper, a learning-based shape descriptor for shape matching is demonstrated. Formulated in a bag-of-words like framework, the proposed method summarizes the local features extracted from certain shape to generate a integrated representation. It contributes to the speed-up of shape matching, since the distance metric in the vector space analysis can be directly applied to compare the constructed global descriptors, eliminating the time consuming stage of local feature matching. Similar to the philosophy in spatial pyramid matching, a strategy for feature division is applied in the phase of encoded feature pooling and vocabulary learning, which helps to construct a more discriminative descriptor incorporating both global and local information. Also, a local contour-based feature extraction method is designed for 2D shapes, while significant properties of the local contours are inspected for the design of feature division rules. The designed local feature extraction method and the feature division rules manage to reduce the variances of shape representation due to the changes in rotation. In addition to 2D shape, we also present a simple and natural method to extend the proposed method to the scenario of 3D shape representation. The proposed shape descriptor is validated on several benchmark data sets for evaluating 2D and 3D shape matching algorithms, and it is observed that the investigated shape descriptor maintains superior discriminative power as well as high time efficiency.

  15. Shape coexistence in the odd-odd nucleus 98Y: The role of the g9 /2 neutron extruder

    Science.gov (United States)

    Urban, W.; Czerwiński, M.; Kurpeta, J.; RzÄ ca-Urban, T.; Wiśniewski, J.; Materna, T.; Iskra, Ł. W.; Smith, A. G.; Ahmad, I.; Blanc, A.; Faust, H.; Köster, U.; Jentschel, M.; Mutti, P.; Soldner, T.; Simpson, G. S.; Pinston, J. A.; de France, G.; Ur, C. A.; Elomaa, V.-V.; Eronen, T.; Hakala, J.; Jokinen, A.; Kankainen, A.; Moore, I. D.; Rissanen, J.; Saastamoinen, A.; Szerypo, J.; Weber, C.; ńystö, J.

    2017-10-01

    Excited states in 98Y, populated in neutron-induced fission of 235U and in spontaneous fission of 248Cm and 252Cf, have been studied by means of γ spectroscopy using the Lohengrin fission-fragment separator at ILL Grenoble and the EXILL, Eurogam2, and Gammasphere Ge arrays. Two new isomers have been found in 98Y: a deformed one with T1 /2=180 (7 ) ns and a rotational band on top of it, and a spherical one with T1 /2=0.45 (15 ) μ s , analogous to the 8+ isomer in 96Y, corresponding to the (νg7/2,π g9 /2) 8+ spherical configuration. Using the JYFLTRAP Penning trap, an accurate excitation energy of 465.7(7) keV has been determined for the 2.36-s isomer in 98Y. This result and the studies of excited levels in 98Zr, populated in β- decay of the isomer, indicate a new spin-parity, Iπ=(7) + for the isomer. The high spin and the decay properties of this isomer suggest the presence of the 9 /2+[404 ] neutron extruder orbital in its structure. This is consistent with the large deformation of the isomer, reported recently. The present work does not provide arguments to support the special role of the ν g7 /2-π g9 /2 interaction (the spin-orbit-partner, or SOP, mechanism).

  16. Surface shape memory in polymers

    Science.gov (United States)

    Mather, Patrick

    2012-02-01

    Many crosslinked polymers exhibit a shape memory effect wherein a permanent shape can be prescribed during crosslinking and arbitrary temporary shapes may be set through network chain immobilization. Researchers have extensively investigated such shape memory polymers in bulk form (bars, films, foams), revealing a multitude of approaches. Applications abound for such materials and a significant fraction of the studies in this area concern application-specific characterization. Recently, we have turned our attention to surface shape memory in polymers as a means to miniaturization of the effect, largely motivated to study the interaction of biological cells with shape memory polymers. In this presentation, attention will be given to several approaches we have taken to prepare and study surface shape memory phenomenon. First, a reversible embossing study involving a glassy, crosslinked shape memory material will be presented. Here, the permanent shape was flat while the temporary state consisted of embossed parallel groves. Further the fixing mechanism was vitrification, with Tg adjusted to accommodate experiments with cells. We observed that the orientation and spreading of adherent cells could be triggered to change by the topographical switch from grooved to flat. Second, a functionally graded shape memory polymer will be presented, the grading being a variation in glass transition temperature in one direction along the length of films. Characterization of the shape fixing and recovery of such films utilized an indentation technique that, along with polarizing microscopy, allowed visualization of stress distribution in proximity to the indentations. Finally, very recent research concerning shape memory induced wrinkle formation on polymer surfaces will be presented. A transformation from smooth to wrinkled surfaces at physiological temperatures has been observed to have a dramatic effect on the behavior of adherent cells. A look to the future in research and

  17. One-particle spectroscopic intensities as a signature of shape phase transition: The γ-unstable case

    Science.gov (United States)

    Alonso, C. E.; Arias, J. M.; Vitturi, A.

    2006-08-01

    We investigate the evolution of one-particle spectroscopic intensities as a possible signature of shape phase transitions. The study describes the odd systems in terms of the interacting boson fermion model. We consider the particular case of an odd j=3/2 particle coupled to an even-even boson core that undergoes a phase transition from spherical U(5) to γ-unstable O(6) situation. At the critical point, our findings are compared with the one-particle spectroscopic intensities that can be obtained within the E(5/4) model proposed by[F. Iachello, Phys. Rev. Lett. 95, 052503 (2005); F. Iachello, in Symmetries and Low-Energy Phase Transitions in Nuclear Structure Physics, edited by G. Lo Bianco (University of Camerino Press, Camerino, Italy, in press)].

  18. Vaccines: Shaping global health.

    Science.gov (United States)

    Pagliusi, Sonia; Ting, Ching-Chia; Lobos, Fernando

    2017-03-14

    The Developing Countries Vaccine Manufacturers' Network (DCVMN) gathered leaders in immunization programs, vaccine manufacturing, representatives of the Argentinean Health Authorities and Pan American Health Organization, among other global health stakeholders, for its 17th Annual General Meeting in Buenos Aires, to reflect on how vaccines are shaping global health. Polio eradication and elimination of measles and rubella from the Americas is a result of successful collaboration, made possible by timely supply of affordable vaccines. After decades of intense competition for high-value markets, collaboration with developing countries has become critical, and involvement of multiple manufacturers as well as public- and private-sector investments are essential, for developing new vaccines against emerging infectious diseases. The recent Zika virus outbreak and the accelerated Ebola vaccine development exemplify the need for international partnerships to combat infectious diseases. A new player, Coalition for Epidemic Preparedness Innovations (CEPI) has made its entrance in the global health community, aiming to stimulate research preparedness against emerging infections. Face-to-face panel discussions facilitated the dialogue around challenges, such as risks of viability to vaccine development and regulatory convergence, to improve access to sustainable vaccine supply. It was discussed that joint efforts to optimizing regulatory pathways in developing countries, reducing registration time by up to 50%, are required. Outbreaks of emerging infections and the global Polio eradication and containment challenges are reminders of the importance of vaccines' access, and of the importance of new public-private partnerships. Copyright © 2017.

  19. Combined Shape and Topology Optimization

    DEFF Research Database (Denmark)

    Christiansen, Asger Nyman

    Shape and topology optimization seeks to compute the optimal shape and topology of a structure such that one or more properties, for example stiffness, balance or volume, are improved. The goal of the thesis is to develop a method for shape and topology optimization which uses the Deformable...... Simplicial Complex (DSC) method. Consequently, we present a novel method which combines current shape and topology optimization methods. This method represents the surface of the structure explicitly and discretizes the structure into non-overlapping elements, i.e. a simplicial complex. An explicit surface...... representation usually limits the optimization to minor shape changes. However, the DSC method uses a single explicit representation and still allows for large shape and topology changes. It does so by constantly applying a set of mesh operations during deformations of the structure. Using an explicit instead...

  20. Neurochemical organization of the nucleus paramedianus dorsalis in the human.

    Science.gov (United States)

    Baizer, Joan S; Baker, James F; Haas, Kristin; Lima, Raquel

    2007-10-24

    We have characterized the neurochemical organization of a small brainstem nucleus in the human brain, the nucleus paramedianus dorsalis (PMD). PMD is located adjacent and medial to the nucleus prepositus hypoglossi (PH) in the dorsal medulla and is distinguished by the pattern of immunoreactivity of cells and fibers to several markers including calcium-binding proteins, a synthetic enzyme for nitric oxide (neuronal nitric oxide synthase, nNOS) and a nonphosphorylated neurofilament protein (antibody SMI-32). In transverse sections, PMD is oval with its long axis aligned with the dorsal border of the brainstem. We identified PMD in eight human brainstems, but found some variability both in its cross-sectional area and in its A-P extent among cases. It includes calretinin immunoreactive large cells with oval or polygonal cell bodies. Cells in PMD are not immunoreactive for either calbindin or parvalbumin, but a few fibers immunoreactive to each protein are found within its central region. Cells in PMD are also immunoreactive to nNOS, and immunoreactivity to a neurofilament protein shows many labeled cells and fibers. No similar region is identified in atlases of the cat, mouse, rat or monkey brain, nor does immunoreactivity to any of the markers that delineate it in the human reveal a comparable region in those species. The territory that PMD occupies is included in PH in other species. Since anatomical and physiological data in animals suggest that PH may have multiple subregions, we suggest that the PMD in human may be a further differentiation of PH and may have functions related to the vestibular control of eye movements.

  1. Separable representation of multichannel nucleon-nucleus optical potentials

    Science.gov (United States)

    Hlophe, L.; Elster, Ch.

    2017-05-01

    Background: One important ingredient for many applications of nuclear physics to astrophysics, nuclear energy, and stockpile stewardship is cross sections for reactions of neutrons with rare isotopes. Since direct measurements are often not feasible, indirect methods, e.g., (d ,p ) reactions, should be used. Those (d ,p ) reactions may be viewed as three-body reactions and described with Faddeev techniques. Purpose: Faddeev equations in momentum space have a long tradition of utilizing separable interactions in order to arrive at sets of coupled integral equations in one variable. Optical potentials representing the effective interactions in the neutron (proton) nucleus subsystem are usually non-Hermitian as well as energy dependent. Including excitations of the nucleus in the calculation requires a multichannel optical potential. The purpose of this paper is to introduce a separable, energy-dependent multichannel representation of complex, energy-dependent optical potentials that contain excitations of the nucleus and that fulfill reciprocity exactly. Methods: Momentum space Lippmann-Schwinger integral equations are solved with standard techniques to obtain the form factors for the separable representation. Results: Starting from energy-dependent multichannel optical potentials for neutron and proton scattering from 12C, separable representations based on a generalization of the Ernst-Shakin-Thaler (EST) scheme are constructed which fulfill reciprocity exactly. Applications to n +12C and p +12C scattering are investigated for energies from 0 to 50 MeV. Conclusions: We find that the energy-dependent separable representation of complex, energy-dependent phenomenological multichannel optical potentials describes scattering data with the same quality as the original potential.

  2. Neutrino–nucleus cross sections for oscillation experiments

    Science.gov (United States)

    Katori, Teppei; Martini, Marco

    2018-01-01

    Neutrino oscillations physics is entering an era of high precision. In this context, accelerator-based neutrino experiments need a reduction in systematic errors to the level of a few percent. Today, one of the most important sources of systematic errors are neutrino–nucleus cross sections which, in the energy region of hundreds of MeV to a few GeV, are known to a precision not exceeding 20%. In this article we review the present experimental and theoretical knowledge of neutrino–nucleus interaction physics. After introducing neutrino-oscillation physics and accelerator-based neutrino experiments, we give an overview of general aspects of neutrino–nucleus cross sections, from both the theoretical and experimental point of view. Then, we focus on these cross sections in different reaction channels. We start with the quasi-elastic and quasi-elastic-like cross section, placing a special emphasis on the multinucleon emission channel, which has attracted a lot of attention in the last few years. We review the main aspects of the different microscopic models for this channel by discussing analogies and the differences among them. The discussion is always driven by a comparison with the experimental data. We then consider the one-pion production channel where agreement between data and theory remains highly unsatisfactory. We describe how to interpret pion data, and then analyze, in particular, the puzzle related to the difficulty of theoretical models and Monte Carlo to simultaneously describe MiniBooNE and MINERvA experimental results. Inclusive cross sections are also discussed, as well as the comparison between the {ν }μ and {ν }e cross sections, relevant for the charge-conjugation-parity violation experiments. The impact of nuclear effects on the reconstruction of neutrino energy and on the determination of the neutrino-oscillation parameters is also reviewed. Finally, we look to the future by discussing projects and efforts in relation to future detectors

  3. Identification of penile inputs to the rat gracile nucleus.

    Science.gov (United States)

    Cothron, Kyle J; Massey, James M; Onifer, Stephen M; Hubscher, Charles H

    2008-03-01

    Neurons in the medullary reticular formation (MRF) of the rat receive a vast array of urogenital inputs. Using select acute and chronic spinal cord lesions to identify the location of the ascending neural circuitries providing either direct or indirect inputs to MRF from the penis, our previous studies demonstrated that the dorsal columns and dorsal half of the lateral funiculus convey low- and high-threshold inputs, respectively. In the present study, the gracile nucleus was targeted as one of the likely sources of low-threshold information from the penis to MRF. Both electrophysiological recordings and neuroanatomical tracing [injection of cholera toxin B subunit (CTB) into a dorsal nerve of the penis] were used. After discrimination of a single neuron responding to penile stimulation, testing for somatovisceral convergence was done (mechanical stimulation of the distal colon and the skin over the entire hindquarters). In 12 rats, a limited number of neurons (43 in total) responded to penile stimulation. Many of these neurons also responded to scrotal stimulation (53.5%, dorsal and/or ventral scrotum) and/or prepuce stimulation (46.5%). Histological reconstruction of the electrode tracks showed that the majority of neurons responding to penile stimulation were located ventrally within the medial one-third of the gracile nucleus surrounding obex. This location corresponded to sparse innervation by CTB-immunoreactive primary afferent terminals. These results indicate that neurons in the gracile nucleus are likely part of the pathway that provides low-threshold penile inputs to MRF, a region known to play an important role in mating processes.

  4. Virtual Technologies and Social Shaping

    OpenAIRE

    Kreps, David

    2010-01-01

    International audience; Virtual Technologies have enabled us all to become publishers and broadcasters. The world of information has become saturated with a multitude of opinions, and opportunities to express them. Track 2 "Virtual Technologies and Social Shaping" of the 9th Conference on Human Choice and Computers (HCC9) explores some of the issues that have arisen in this new information society, how we are shaped by it, and how we shape it, through i) two papers addressing issues of identi...

  5. Detail-replicating shape stretching

    OpenAIRE

    Alhashim, Ibraheem Abbas

    2011-01-01

    Mesh deformation methods are useful for creating shape variations. Existing deformation techniques work on preserving surface details under bending and twisting operations. Stretching different parts of a shape is also a useful operation for generating shape variations. Under stretching, texture-like geometric details should not be preserved but rather replicated. We propose a simple method that help create model variation by applying non-uniform stretching on 3D models. The method replicates...

  6. Cloud condensation nucleus behaviour of selected dicarboxylic acids

    DEFF Research Database (Denmark)

    Poulsen, Mia Frosch Mogensbæk; Nielsen, Ole Faurskov; Bilde, Merete

    Due to relatively high water solubilities and low volatilities under ambient conditions, dicarboxylic acids have a high potential for forming aerosols, i.e. act as cloud condensation nuclei (CCN). Futhermore, dicarboxylic acids have been detected in atmospheric aerosols on many different sites (e.......g. Anttila et al, 2005). Particles composed of two such compounds, namely glutaric acid and pimelic acid, have been studied using a cloud condensation nucleus counter (University of Wyoming, Model 100B). The behaviour of pimelic acid seems to agree quite well with the predictions of Köhler theory. This...

  7. First allowed bandcrossing in neutron deficient nucleus {sup 141}Tb

    Energy Technology Data Exchange (ETDEWEB)

    Medina, N.H.; Oliveira, J.R.B.; Cybulska, E.W.; Rao, M.N.; Ribas, R.V.; Rizzutto, M.A.; Seale, W.A. [Sao Paulo Univ., SP (Brazil). Inst. de Fisica; Espinoza-Quinones, F.R. [Universidade Estadual do Oeste do Parana, Toledo, PR (Brazil). Centro de Engenharia e Ciencias Exatas; Bazzacco, D.; Brandolini, F.; Lunardi, S.; Petrache, C.M.; Podolyak, Zs.; Rossi-Alvarez, C.; Soramel, F.; Ur, C.A. [Istituto Nazionale di Fisica Nucleare, Padova (Italy); Cardona, M.A.; Angelis, G. de; Napoli, D.R.; Spolaore, P.; Gadea, A.; Acua, D. de; Poli, M. de; Farnea, E.; Foltescu, D.; Ionescu-Bujor, M.; Iordachescu, A. [Istituto Nazionale di Fisica Nucleare, Legnaro (Italy). Laboratori Nazionali

    2004-09-15

    The neutron deficient {sup 141}Tb nucleus has been studied with the {sup 92}Mo ({sup 54}Fe, {alpha}-) reaction at 240-MeV incident energy and the multidetector array GASP. For the yrast {pi}h{sub 11/2} decoupled band, excited states up to 6.7 MeV and spin up to 47=2{sup -} have been observed. This band presents an upbend at rotational frequency of Plank constant{omega}=0:38 MeV due to the alignment of h{sub 11}/{sub 2} protons. The results are discussed in terms of the Cranking model. (author)

  8. Neutrino-nucleus interactions and the determination of oscillation parameters

    Science.gov (United States)

    Benhar, Omar; Huber, Patrick; Mariani, Camillo; Meloni, Davide

    2017-07-01

    We review the status and prospects of theoretical studies of neutrino-nucleus interactions, and discuss the influence of the treatment of nuclear effects on the determination of oscillation parameters. The models developed to describe the variety of reaction mechanisms contributing to the nuclear cross sections are analyzed, with emphasis placed on their capability to explain the large body of available electron scattering data. The impact of the uncertainties associated with the description of nuclear structure and dynamics on the determination of oscillation parameters is illustrated through examples, and possible avenues towards a better understanding of the signals detected by accelerator-based experiments are outlined.

  9. Cellinoid Shape Model for Asteroids

    Science.gov (United States)

    Lu, Xiaoping; Zhao, Haibin; You, Zhong

    2014-08-01

    The ellipsoid shape model plays an important role in physical research on asteroids. However, its symmetric structure cannot practically simulate real asteroids. This article applies a general shape model, named the cellinoid, instead of the ellipsoid model to simulate the asymmetric shape of asteroids. The cellinoid shape model consists of eight octants of ellipsoids having different semi-axes, with the constraint that adjacent octants must have two equal semi-axes in common. Totally, the shape of the cellinoid model is controlled by six parameters, not three as in the case of the shape of the ellipsoid. Using this shape model, the brightness of asteroids observed from the Earth can be fitted numerically by the surface triangularization of the cellinoid. The Levenberg-Marquardt algorithm is also employed here to solve a nonlinear minimization problem. Owing to the asymmetric shape of the cellinoid, the physical parameters of asteroids, such as the rotation period and pole orientation, can be fitted more accurately than in the case of the ellipsoid model. Finally, this is confirmed numerically by applying the shape to both synthetic light curves and real light curves of asteroids. Additionally, the center of mass and moment of inertia of the cellinoid are analyzed explicitly.

  10. Pulse shaping with transmission lines

    Science.gov (United States)

    Wilcox, Russell B.

    1987-01-01

    A method and apparatus for forming shaped voltage pulses uses passive reflection from a transmission line with nonuniform impedance. The impedance of the reflecting line varies with length in accordance with the desired pulse shape. A high voltage input pulse is transmitted to the reflecting line. A reflected pulse is produced having the desired shape and is transmitted by pulse removal means to a load. Light activated photoconductive switches made of silicon can be utilized. The pulse shaper can be used to drive a Pockels cell to produce shaped optical pulses.

  11. Women in Shape Modeling Workshop

    CERN Document Server

    Tari, Sibel

    2015-01-01

    Presenting the latest research from the growing field of mathematical shape analysis, this volume is comprised of the collaborations of participants of the Women in Shape Modeling (WiSh) workshop, held at UCLA's Institute for Pure and Applied Mathematics in July 2013. Topics include: Simultaneous spectral and spatial analysis of shape Dimensionality reduction and visualization of data in tree-spaces, such as classes of anatomical trees like airways and blood vessels Geometric shape segmentation, exploring shape segmentation from a Gestalt perspective, using information from the Blum medial axis of edge fragments in an image Representing and editing self-similar details on 3D shapes, studying shape deformation and editing techniques Several chapters in the book directly address the problem of continuous measures of context-dependent nearness and right shape models. Medical and biological applications have been a major source of motivation in shape research, and key topics are examined here in detail. All...

  12. The Shaped Charge Concept. Part 3. Applications of Shaped Charges

    Science.gov (United States)

    1990-10-01

    perforating charges. Well perforator cones usually have an apex angle of 450 to About 600. The smaller angle increases penetation , but the hole size is...hole digging and underwaterdemlition via shaped charles . Byei (1949.1950) picacuw novel shaped chare designs for mining, hole drilling, and boulde

  13. Red nucleus and rubrospinal tract disorganization in the absence of Pou4f1

    Directory of Open Access Journals (Sweden)

    Jesus E. eMartinez-Lopez

    2015-02-01

    Full Text Available The red nucleus is a neuronal population that plays an important role in forelimb motor control and locomotion. Histologically it is subdivided into two subpopulations, the parvocellular red nucleus located in the diencephalon and the magnocellular red nucleus in the mesencephalon. The red nucleus integrates signals from motor cortex and cerebellum and projects to spinal cord interneurons and motor neurons through the rubrospinal tract. Pou4f1 is a transcription factor highly expressed in this nucleus that has been related to its specification. Here we profoundly analyzed consequences of Pou4f1 loss-of-function in development, maturation and axonal projection of the red nucleus. Surprisingly, red nucleus neurons are specified and maintained in the mutant, no cell death was detected. Nevertheless, the nucleus appeared disorganized with a strong delay in radial migration and with a wider neuronal distribution; the neurons did not form a compacted population as they do in controls, Robo1 and Slit2 were miss-expressed. Cplx1 and Npas1, expressed in the red nucleus, are transcription factors involved in neurotransmitter release, neuronal maturation and motor function processes among others. In our mutant mice, both transcription factors are lost, suggesting an abnormal maturation of the red nucleus. The resulting altered nucleus occupied a wider territory. Finally, we examined rubrospinal tract development and found that the red nucleus neurons were able to project to the spinal cord but their axons appeared defasciculated. These data suggest that Pou4f1 is necessary for the maturation of red nucleus neurons but not for their specification and maintenance.

  14. Shape coexistence in the neutron-deficient mercury isotopes studied through Coulomb excitation

    CERN Document Server

    Bree, Nick

    This thesis describes the analysis and results of a series of Coulomb-excitation experiments on even-even neutron-deficient mercury isotopes aimed at obtaining a more detailed description of shape coexistence. Two experimental campaigns have been undertaken in the Summer of 2007 and 2008. Pure beams of 182,184,186,188Hg were produced and accelerated at the REX-ISOLDE radioactive-beam facility, located at CERN (Geneva, Switzerland). The beams were guided to collide with a stable target to induce Coulomb excitation. The scattered particles were registered by a double-sided silicon strip detector, and the emitted gamma rays by the MINIBALL gamma-ray spectrometer. The motivation to study these mercury isotopes, focused around shape coexistence in atomic nuclei, is addressed in chapter 1, as well as an overview of the knowledge in this region of the nuclear chart. A theoretical description of Coulomb excitation is presented in the second chapter, while the third chapter describes the setup employed for the experim...

  15. Evidence that urocortin is absent from neurons of the Edinger-Westphal nucleus in pigeons

    Directory of Open Access Journals (Sweden)

    Cavani J.A.

    2003-01-01

    Full Text Available The Edinger-Westphal nucleus (EWN is a central preganglionic parasympathetic cell group that gives rise to cholinergic input to the ciliary ganglion, thereby regulating several neurovegetative ocular functions. Recently, the supposed presence of the neuropeptide urocortin (UCN has been reported in EWN neurons in rodent brain. The purpose of the present study was to examine the distribution of UCN in avian brain and to investigate by immunohistochemical analysis the possible use of this substance as an EWN marker in a non-mammalian class of vertebrates. Brain tissue of pigeons was incubated with a specific antibody against UCN and the results showed labeling of many small neurons, forming a double wing in the dorsal mesodiencephalic transition area. Their size and shape, however, differed from those of EWN neurons, and they were preferentially located rostral to the EWN. Double-label experiments employing an antibody against the enzyme choline acetyltransferase (ChAT showed that UCN is not localized to the cholinergic cells of the EWN and confirmed the rostral distributionof UCN never overlapping the ChAT+ EWN cells. Taken together, these results suggest that, at least in pigeons, the UCN+ population does not belong to the traditionally defined EWN.

  16. Borna Disease Virus Assembles Porous Cage-like Viral Factories in the Nucleus.

    Science.gov (United States)

    Hirai, Yuya; Hirano, Yasuhiro; Matsuda, Atsushi; Hiraoka, Yasushi; Honda, Tomoyuki; Tomonaga, Keizo

    2016-12-09

    Animal-derived RNA viruses frequently generate viral factories in infected cells. However, the details of how RNA viruses build such intracellular structures are poorly understood. In this study, we examined the structure and formation of the viral factories, called viral speckle of transcripts (vSPOTs), that are produced in the nuclei of host cells by Borna disease virus (BDV). Super-resolution microscopic analysis showed that BDV assembled vSPOTs as intranuclear cage-like structures with 59-180-nm pores. The viral nucleoprotein formed the exoskeletons of vSPOTs, whereas the other viral proteins appeared to be mainly localized within these structures. In addition, stochastic optical reconstruction microscopy revealed that filamentous structures resembling viral ribonucleoprotein complexes (RNPs) appeared to protrude from the outer surfaces of the vSPOTs. We also found that vSPOTs disintegrated into RNPs concurrently with the breakdown of the nuclear envelope during mitosis. These observations demonstrated that BDV generates viral replication factories whose shape and formation are regulated, suggesting the mechanism of the integrity of RNA virus persistent infection in the nucleus. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  17. Borna Disease Virus Assembles Porous Cage-like Viral Factories in the Nucleus*

    Science.gov (United States)

    Hirai, Yuya; Hirano, Yasuhiro; Matsuda, Atsushi; Hiraoka, Yasushi; Honda, Tomoyuki; Tomonaga, Keizo

    2016-01-01

    Animal-derived RNA viruses frequently generate viral factories in infected cells. However, the details of how RNA viruses build such intracellular structures are poorly understood. In this study, we examined the structure and formation of the viral factories, called viral speckle of transcripts (vSPOTs), that are produced in the nuclei of host cells by Borna disease virus (BDV). Super-resolution microscopic analysis showed that BDV assembled vSPOTs as intranuclear cage-like structures with 59–180-nm pores. The viral nucleoprotein formed the exoskeletons of vSPOTs, whereas the other viral proteins appeared to be mainly localized within these structures. In addition, stochastic optical reconstruction microscopy revealed that filamentous structures resembling viral ribonucleoprotein complexes (RNPs) appeared to protrude from the outer surfaces of the vSPOTs. We also found that vSPOTs disintegrated into RNPs concurrently with the breakdown of the nuclear envelope during mitosis. These observations demonstrated that BDV generates viral replication factories whose shape and formation are regulated, suggesting the mechanism of the integrity of RNA virus persistent infection in the nucleus. PMID:27803166

  18. Quantitative 3D Analysis of Nuclear Morphology and Heterochromatin Organization from Whole-Mount Plant Tissue Using NucleusJ.

    Science.gov (United States)

    Desset, Sophie; Poulet, Axel; Tatout, Christophe

    2018-01-01

    Image analysis is a classical way to study nuclear organization. While nuclear organization used to be investigated by colorimetric or fluorescent labeling of DNA or specific nuclear compartments, new methods in microscopy imaging now enable qualitative and quantitative analyses of chromatin pattern, and nuclear size and shape. Several procedures have been developed to prepare samples in order to collect 3D images for the analysis of spatial chromatin organization, but only few preserve the positional information of the cell within its tissue context. Here, we describe a whole mount tissue preparation procedure coupled to DNA staining using the PicoGreen ® intercalating agent suitable for image analysis of the nucleus in living and fixed tissues. 3D Image analysis is then performed using NucleusJ, an open source ImageJ plugin, which allows for quantifying variations in nuclear morphology such as nuclear volume, sphericity, elongation, and flatness as well as in heterochromatin content and position in respect to the nuclear periphery.

  19. Finding Hierarchical and Overlapping Dense Subgraphs using Nucleus Decompositions

    Energy Technology Data Exchange (ETDEWEB)

    Seshadhri, Comandur [The Ohio State Univ., Columbus, OH (United States); Pinar, Ali [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Sariyuce, Ahmet Erdem [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Catalyurek, Umit [The Ohio State Univ., Columbus, OH (United States)

    2014-11-01

    Finding dense substructures in a graph is a fundamental graph mining operation, with applications in bioinformatics, social networks, and visualization to name a few. Yet most standard formulations of this problem (like clique, quasiclique, k-densest subgraph) are NP-hard. Furthermore, the goal is rarely to nd the \\true optimum", but to identify many (if not all) dense substructures, understand their distribution in the graph, and ideally determine a hierarchical structure among them. Current dense subgraph nding algorithms usually optimize some objective, and only nd a few such subgraphs without providing any hierarchy. It is also not clear how to account for overlaps in dense substructures. We de ne the nucleus decomposition of a graph, which represents the graph as a forest of nuclei. Each nucleus is a subgraph where smaller cliques are present in many larger cliques. The forest of nuclei is a hierarchy by containment, where the edge density increases as we proceed towards leaf nuclei. Sibling nuclei can have limited intersections, which allows for discovery of overlapping dense subgraphs. With the right parameters, the nuclear decomposition generalizes the classic notions of k-cores and k-trusses. We give provable e cient algorithms for nuclear decompositions, and empirically evaluate their behavior in a variety of real graphs. The tree of nuclei consistently gives a global, hierarchical snapshot of dense substructures, and outputs dense subgraphs of higher quality than other state-of-theart solutions. Our algorithm can process graphs with tens of millions of edges in less than an hour.

  20. Neutrino-nucleus reactions based on recent structure studies

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Toshio [Department of Physics and Graduate School of Integrated Basic Sciences, College of Humanities and Sciences, Nihon University, Sakurajosui 3-25-40, Setagaya-ku, Tokyo 156-8550 (Japan); National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan)

    2015-05-15

    Neutrino-nucleus reactions are studied with the use of new shell model Hamiltonians, which have proper tensor components in the interactions and prove to be successful in the description of Gamow-Teller (GT) strengths in nuclei. The new Hamiltonians are applied to obtain new neutrino-nucleus reaction cross sections in {sup 12}C, {sup 13}C, {sup 56}Fe and {sup 56}Ni induced by solar and supernova neutrinos. The element synthesis by neutrino processes in supernova explosions is discussed with the new cross sections. The enhancement of the production yields of {sup 7}Li, {sup 11}B and {sup 55}Mn is obtained while fragmented GT strength in {sup 56}Ni with two-peak structure is found to result in smaller e-capture rates at stellar environments. The monopole-based universal interaction with tensor force of π+ρ meson exchanges is used to evaluate GT strength in {sup 40}Ar and ν-induced reactions on {sup 40}Ar. It is found to reproduce well the experimental GT strength in {sup 40}Ar.

  1. Axonal branching patterns of nucleus accumbens neurons in the rat.

    Science.gov (United States)

    Tripathi, Anushree; Prensa, Lucía; Cebrián, Carolina; Mengual, Elisa

    2010-11-15

    The patterns of axonal collateralization of nucleus accumbens (Acb) projection neurons were investigated in the rat by means of single-axon tracing techniques using the anterograde tracer biotinylated dextran amine. Seventy-three axons were fully traced, originating from either the core (AcbC) or shell (AcbSh) compartment, as assessed by differential calbindin D28k-immunoreactivity. Axons from AcbC and AcbSh showed a substantial segregation in their targets; target areas were either exclusively or preferentially innervated from AcbC or AcbSh. Axon collaterals in the subthalamic nucleus were found at higher than expected frequencies; moreover, these originated exclusively in the dorsal AcbC. Intercompartmental collaterals were observed from ventral AcbC axons into AcbSh, and likewise, interconnections at pallidal and mesencephalic levels were also observed, although mostly from AcbC axons toward AcbSh targets, possibly supporting crosstalk between the two subcircuits at several levels. Cell somata giving rise to short-range accumbal axons, projecting to the ventral pallidum (VP), were spatially intermingled with others, giving rise to long-range axons that innervated VP and more caudal targets. This anatomical organization parallels that of the dorsal striatum and provides the basis for possible dual direct and indirect actions from a single axon on either individual or small sets of neurons. Copyright © 2010 Wiley-Liss, Inc.

  2. Commissural neurons in the rat ventral cochlear nucleus.

    Science.gov (United States)

    Doucet, John R; Lenihan, Nicole M; May, Bradford J

    2009-06-01

    Commissural neurons connect the cochlear nucleus complexes of both ears. Previous studies have suggested that the neurons may be separated into two anatomical subtypes on the basis of percent apposition (PA); that is, the percentage of the soma apposed by synaptic terminals. The present study combined tract tracing with synaptic immunolabeling to compare the soma area, relative number, and location of Type I (low PA) and Type II (high PA) commissural neurons in the ventral cochlear nucleus (VCN) of rats. Confocal microscopic analysis revealed that 261 of 377 (69%) commissural neurons have medium-sized somata with Type I axosomatic innervation. The commissural neurons also showed distinct topographical distributions. The majority of Type I neurons were located in the small cell cap of the VCN, which serves as a nexus for regulatory pathways within the auditory brainstem. Most Type II neurons were found in the magnocellular core. This anatomical dichotomy should broaden current views on the function of the commissural pathway that stress the fast inhibitory interactions generated by Type II neurons. The more prevalent Type I neurons may underlie slow regulatory influences that enhance binaural processing or the recovery of function after injury.

  3. Monte Carlo Simulation for Statistical Decay of Compound Nucleus

    Directory of Open Access Journals (Sweden)

    Chadwick M.B.

    2012-02-01

    Full Text Available We perform Monte Carlo simulations for neutron and γ-ray emissions from a compound nucleus based on the Hauser-Feshbach statistical theory. This Monte Carlo Hauser-Feshbach (MCHF method calculation, which gives us correlated information between emitted particles and γ-rays. It will be a powerful tool in many applications, as nuclear reactions can be probed in a more microscopic way. We have been developing the MCHF code, CGM, which solves the Hauser-Feshbach theory with the Monte Carlo method. The code includes all the standard models that used in a standard Hauser-Feshbach code, namely the particle transmission generator, the level density module, interface to the discrete level database, and so on. CGM can emit multiple neutrons, as long as the excitation energy of the compound nucleus is larger than the neutron separation energy. The γ-ray competition is always included at each compound decay stage, and the angular momentum and parity are conserved. Some calculations for a fission fragment 140Xe are shown as examples of the MCHF method, and the correlation between the neutron and γ-ray is discussed.

  4. Gas inflows towards the nucleus of NGC 1358

    Science.gov (United States)

    Schnorr-Müller, Allan; Storchi-Bergmann, Thaisa; Nagar, Neil M.; Robinson, Andrew; Lena, Davide

    2017-11-01

    We use optical spectra from the inner 1.8 × 2.5 kpc2 of the Seyfert 2 galaxy NGC 1358, obtained with the GMOS integral field spectrograph on the Gemini South telescope at a spatial resolution of ≈ 165 pc, to assess the feeding and feedback processes in this nearby active galaxy. Five gaseous kinematical components are observed in the emission line profiles. One of the components is present in the entire field-of-view and we interpret it as due to gas rotating in the disc of the galaxy. Three of the remaining components we interpret as associated with active galactic nucleus (AGN) feedback: a compact unresolved outflow in the inner 1 arcsec and two gas clouds observed at opposite sides of the nucleus, which we propose have been ejected in a previous AGN burst. The disc component velocity field is strongly disturbed by a large-scale bar. The subtraction of a velocity model combining both rotation and bar flows reveals three kinematic nuclear spiral arms: two in inflow and one in outflow. We estimate the mass inflow rate in the inner 180 pc obtaining \\dot{M}_{in} ≈ 1.5 × 10-2 M⊙ yr-1, about 160 times larger than the accretion rate necessary to power this AGN.

  5. Pion-nucleus scattering at around the DELTA (1232) resonance

    CERN Document Server

    Ahmed, H S; Rahman, M A; Rahman, S N

    2003-01-01

    The pion-nucleus scattering around 200 MeV and just above 1200 MeV is dominated by strong, broad DELTA (3,3) and weak resonances in the pi sup+-N interaction. The interaction to a first approximation can be described as diffraction process. Since it is well known that the strength of the pi sup + N and pi sup - N interactions are quite different from each other at the resonances, the analyses of differential cross section for pi sup + N and pi sup - N elastic scattering data in the region of low-lying pion-nucleus resonances will be a good test of different strengths. In the present work we analyze pions scattering from nuclei sup 9 Be, sup 2 sup 8 Si, sup 5 sup 8 Ni, sup 8 sup 9 Y and sup 2 sup 0 sup 8 Pb at incident pion energies between 50 and 291 MeV within the framework of the three parameter version of the Strong Absorption Model of Frahn and Venter. All the oscillations in the elastic scattering experimental data and for the experimental angular distribution leading to 2 sup + and 3 sup - collective st...

  6. Calcium signaling in synapse-to-nucleus communication.

    Science.gov (United States)

    Hagenston, Anna M; Bading, Hilmar

    2011-11-01

    Changes in the intracellular concentration of calcium ions in neurons are involved in neurite growth, development, and remodeling, regulation of neuronal excitability, increases and decreases in the strength of synaptic connections, and the activation of survival and programmed cell death pathways. An important aspect of the signals that trigger these processes is that they are frequently initiated in the form of glutamatergic neurotransmission within dendritic trees, while their completion involves specific changes in the patterns of genes expressed within neuronal nuclei. Accordingly, two prominent aims of research concerned with calcium signaling in neurons are determination of the mechanisms governing information conveyance between synapse and nucleus, and discovery of the rules dictating translation of specific patterns of inputs into appropriate and specific transcriptional responses. In this article, we present an overview of the avenues by which glutamatergic excitation of dendrites may be communicated to the neuronal nucleus and the primary calcium-dependent signaling pathways by which synaptic activity can invoke changes in neuronal gene expression programs.

  7. Cajal's contribution to the knowledge of the neuronal cell nucleus.

    Science.gov (United States)

    Lafarga, Miguel; Casafont, Iñigo; Bengoechea, Rocio; Tapia, Olga; Berciano, Maria T

    2009-08-01

    In 1906, the Spanish neurobiologist Santiago Ramón y Cajal was awarded the Nobel Prize in Physiology or Medicine in recognition of his work on the structure of neurons and their connections. Cajal is commonly regarded as the father of modern neuroscience. What is less well known is that Cajal also had a great interest in intracellular neuronal structures and developed the reduced silver nitrate method for the study of neurofibrils (neurofilaments) and nuclear subcompartments. It was in 1903 that Cajal discovered the "accessory body" ("Cajal body") and seven years later, published an article on the organization of the cell nucleus in mammalian neurons that represents a masterpiece of nuclear structure at the light microscopy level. In addition to the accessory body, it includes the analysis of several nuclear components currently recognized as fibrillar centers of the nucleolus, nuclear speckles of splicing factors, transcription foci, nuclear matrix, and the double nuclear membrane. The aim of this article is to revisit Cajal's contributions to the knowledge of the neuronal nucleus in light of our current understanding of nuclear structure and function.

  8. Inositide-specific phospholipase C signalling in the nucleus

    Directory of Open Access Journals (Sweden)

    FA Manzoli

    2009-12-01

    Full Text Available The nucleus of eukaryotic cells contains all the information needed for cell proliferation and differentiation, however the initiation of these programmes are dependent on the signalling pathway elicited by different agonists. The existence of a nuclear phosphoinositide signalling stems from the early evidence that isolated nuclei posses the lipid kinases capable of phosphorylating phosphatidylinositol (PI and phosphatidylinositol 4-phosphate (PIP. The synthesis of phosphatidylinositol 4,5- phosphate (PIP2 was clearly increased only in the nuclear fraction from Friend cells terminally differentiated towards erythrocytes (Cocco et al., 1987. On the contrary its amount along with that of PIP was decreased in nuclei of Swiss 3T3 cells stimulated to grow with insulin-like growth factor-I (IGFI (Manzoli et al., 1989. Following these early observations we and others have demonstrated in several cell type the participation of the whole phosphoinositide cycle in the nucleus (Cocco et al., 1994; Martelli et al., 1992; Divecha et al., 1991; Martelli et al., 1994; Mazzoni et al., 1992. Here we review the most recent achievements on this issue.

  9. Cerebellar fastigial nucleus influence on ipsilateral abducens activity during saccades.

    Science.gov (United States)

    Kojima, Yoshiko; Robinson, Farrel R; Soetedjo, Robijanto

    2014-04-01

    To characterize the cerebellar influence on neurons in the abducens (ABD) nucleus, we recorded ABD neurons before and after we inactivated the caudal part of the ipsilateral cerebellar fastigial nucleus (cFN) with muscimol injection. cFN activity influences the horizontal component of saccades. cFN inactivation increased the activity of most ipsilateral ABD neurons (19/22 in 2 monkeys) during ipsiversive (hypermetric) saccades, primarily by increasing burst duration. During contraversive (hypometric) saccades, the off-direction pause of most (10/15) ABD neurons was shorter than normal because of the early resumption of ABD activity. Early ABD firing caused the early contraction of antagonist muscles that reduced eye rotation and made contraversive saccades hypometric. Thus the cerebellum controls ipsilateral ABD activity by truncating on-direction bursts during ipsiversive saccades and extending off-direction pauses during contraversive saccades. We conclude that cFN output keeps saccades accurate by controlling when ABD on-direction bursts and off-direction pauses end.

  10. Robust, Optimal Subsonic Airfoil Shapes

    Science.gov (United States)

    Rai, Man Mohan

    2014-01-01

    A method has been developed to create an airfoil robust enough to operate satisfactorily in different environments. This method determines a robust, optimal, subsonic airfoil shape, beginning with an arbitrary initial airfoil shape, and imposes the necessary constraints on the design. Also, this method is flexible and extendible to a larger class of requirements and changes in constraints imposed.

  11. Shape Factor Modeling and Simulation

    Science.gov (United States)

    2016-06-01

    10 3. Shape Factor Distributions for Natural Fragments 12 3.1 Platonic Solids and Uniform Viewing from All Viewpoints 12 3.2 Natural Fragments from...12 Fig. 9 The 5 Platonic solids. ............................................................. 12 Fig. 10 Mean shape factor of...of the 5 Platonic solids............................................ 13 Table 3 Sequence of viewing angles in Icosahedron Gage

  12. Shape memory alloy based motor

    Indian Academy of Sciences (India)

    http://www.ias.ac.in/article/fulltext/sadh/033/05/0699-0712. Keywords. Shape Memory Alloy (SMA); poly phase; rotary actuator; torque; ripple. Abstract. Design and characterization of a new shape memory alloy wire based Poly Phase Motor has been reported in this paper. The motor can be used either in stepping mode or ...

  13. Pileup subtraction for jet shapes

    CERN Document Server

    Soyez, Gregory; Kim, Jihun; Dutta, Souvik; Cacciari, Matteo

    2013-01-01

    Jet shapes have the potential to play a role in many LHC analyses, for example in quark-gluon discrimination or jet substructure analyses for hadronic decays of boosted heavy objects. Most shapes, however, are significantly affected by pileup. We introduce a general method to correct for pileup effects in shapes, which acts event-by-event and jet-by-jet, and accounts also for hadron masses. It involves a numerical determination, for each jet, of a given shape's susceptibility to pileup. Together with existing techniques for determining the level of pileup, this then enables an extrapolation to zero pileup. The method can be used for a wide range of jet shapes and we show its successful application in the context of quark/gluon discrimination and top-tagging.

  14. Functional and shape data analysis

    CERN Document Server

    Srivastava, Anuj

    2016-01-01

    This textbook for courses on function data analysis and shape data analysis describes how to define, compare, and mathematically represent shapes, with a focus on statistical modeling and inference. It is aimed at graduate students in analysis in statistics, engineering, applied mathematics, neuroscience, biology, bioinformatics, and other related areas. The interdisciplinary nature of the broad range of ideas covered—from introductory theory to algorithmic implementations and some statistical case studies—is meant to familiarize graduate students with an array of tools that are relevant in developing computational solutions for shape and related analyses. These tools, gleaned from geometry, algebra, statistics, and computational science, are traditionally scattered across different courses, departments, and disciplines; Functional and Shape Data Analysis offers a unified, comprehensive solution by integrating the registration problem into shape analysis, better preparing graduate students for handling fu...

  15. Alignment processes and shape variations in sup 184 Pt

    Energy Technology Data Exchange (ETDEWEB)

    Carpenter, M.P.; Bingham, C.R.; Courtney, L.H.; Janzen, V.P.; Larabee, A.J.; Liu, Z.M.; Riedinger, L.L.; Schmitz, W. (Tennessee Univ., Knoxville (USA). Dept. of Physics); Bengtsson, R.; Bengtsson, T.; Nazarewicz, W.; Zhang, J.Y. (Joint Inst. for Heavy Ion Research, Oak Ridge, TN (USA)); Johansson, J.K.; Popescu, D.G.; Waddington, J.C. (McMaster Univ., Hamilton, Ontario (Canada)); Baktash, C.; Halbert, M.L.; Johnson, N.R.; Lee, I.Y.; Schutz, Y.S. (Oak Ridge National Lab., TN (USA). Holifield Heavy Ion Research Facility); Nyberg, J.; Johnson, A.; Wyss, R. (Manne Siegbahn Inst. of Physics, Stockholm (Sweden) Royal Inst. of Tech., Stockholm (Sweden). Physics Dept. 1); Dubuc, J.; Kajrys, G.; Monaro, S.; Pilotte, S. (Montreal Univ., Quebec (Canada)); Honkanen, K.; Sarantites, D.G. (Washington Univ., St. Louis, MO (USA)); Haenni, D.R. (Texas A and M Univ., College Station (USA). Cyclotron Inst.)

    1990-06-25

    High-spin states in the transitional nucleus {sup 184}Pt were populated via the reactions {sup 154}Sm({sup 34}S, 4n){sup 184}Pt and {sup 172}Yb({sup 16}O, 4n){sup 184}Pt. The yrast band was extended up to I=28 {Dirac h} and six new side bands built on both neutron and proton quasiparticle configurations were observed. Shell correction-type calculations indicate variations of the nuclear shape in different bands, especially as a result of band crossings due to the process of angular momentum alignment. Comparison of the band characteristics are made between {sup 184}Pt and eight adjacent nuclei. The pattern of band crossings in these nine nuclei is considered from the viewpoint of blocking comparisons and of theoretical calculations. The competition between low-frequency {nu}i{sub 13/2} and {pi}h{sub 9/2} band crossings is discussed. (orig.).

  16. Tolerance to Sound Intensity of Binaural Coincidence Detection in the Nucleus Laminaris of the Owl

    OpenAIRE

    Peña, Jose Luis; Viete, Svenja; Albeck, Yehuda; Konishi, Masakazu

    1996-01-01

    Neurons of the owl's nucleus laminaris serve as coincidence detectors for measurement of interaural time difference. The discharge rate of nucleus laminaris neurons for both monaural and binaural stimulation increased with sound intensity until they reached an asymptote. Intense sounds affected neither the ratio between binaural and monaural responses nor the interaural time difference for which nucleus laminaris neurons were selective. Theoretical analysis showed that high afferent discharge...

  17. Deformation and mixing of co-existing shapes in the neutron-deficient polonium isotopes

    CERN Document Server

    AUTHOR|(CDS)2078559; Huyse, Mark

    The neutron-deficient polonium isotopes, with only 2 protons outside the Z = 82 shell closure, are situated in an interesting region of the nuclear chart. In the neighboring lead (Z = 82) and mercury (Z = 80) isotopes, experimental and theoretical efforts identified evidence of shape coexistence. Shape coexistence is the remarkable phenomenon in which two or more distinct types of deformation occur in states of the same angular momentum and similar excitation energy in a nucleus. The neutron-deficient polonium isotopes have also been studied intensively, experimentally as well as theoretically. The closed neutron-shell nucleus 210Po (N = 126) manifests itself as a two-particle nucleus where most of the excited states can be explained by considering the degrees of freedom of the two valence protons outside of 208Pb. The near-constant behavior of the yrast 2+1 and 4+1 states in the isotopes with mass 200 ≤ A ≤ 208 can be explained by coupling the two valence protons to a vibrating lead core. 200Po seems to ...

  18. Intrinsic functional connectivity of the central nucleus of the amygdala and bed nucleus of the stria terminalis.

    Science.gov (United States)

    Gorka, Adam X; Torrisi, Salvatore; Shackman, Alexander J; Grillon, Christian; Ernst, Monique

    2017-04-06

    The central nucleus of the amygdala (CeA) and bed nucleus of the stria terminalis (BNST), two nuclei within the central extended amygdala, function as critical relays within the distributed neural networks that coordinate sensory, emotional, and cognitive responses to threat. These structures have overlapping anatomical projections to downstream targets that initiate defensive responses. Despite these commonalities, researchers have also proposed a functional dissociation between the CeA and BNST, with the CeA promoting responses to discrete stimuli and the BNST promoting responses to diffuse threat. Intrinsic functional connectivity (iFC) provides a means to investigate the functional architecture of the brain, unbiased by task demands. Using ultra-high field neuroimaging (7-Tesla fMRI), which provides increased spatial resolution, this study compared the iFC networks of the CeA and BNST in 27 healthy individuals. Both structures were coupled with areas of the medial prefrontal cortex, hippocampus, thalamus, and periaqueductal gray matter. Compared to the BNST, the bilateral CeA was more strongly coupled with the insula and regions that support sensory processing, including thalamus and fusiform gyrus. In contrast, the bilateral BNST was more strongly coupled with regions involved in cognitive and motivational processes, including the dorsal paracingulate gyrus, posterior cingulate cortex, and striatum. Collectively, these findings suggest that responses to sensory stimulation are preferentially coordinated by the CeA and cognitive and motivational responses are preferentially coordinated by the BNST. Published by Elsevier Inc.

  19. Hearing assessment during deep brain stimulation of the central nucleus of the inferior colliculus and dentate cerebellar nucleus in rat

    Directory of Open Access Journals (Sweden)

    Jasper V. Smit

    2017-10-01

    Full Text Available Background Recently it has been shown in animal studies that deep brain stimulation (DBS of auditory structures was able to reduce tinnitus-like behavior. However, the question arises whether hearing might be impaired when interfering in auditory-related network loops with DBS. Methods The auditory brainstem response (ABR was measured in rats during high frequency stimulation (HFS and low frequency stimulation (LFS in the central nucleus of the inferior colliculus (CIC, n = 5 or dentate cerebellar nucleus (DCBN, n = 5. Besides hearing thresholds using ABR, relative measures of latency and amplitude can be extracted from the ABR. In this study ABR thresholds, interpeak latencies (I–III, III–V, I–V and V/I amplitude ratio were measured during off-stimulation state and during LFS and HFS. Results In both the CIC and the CNBN groups, no significant differences were observed for all outcome measures. Discussion DBS in both the CIC and the CNBN did not have adverse effects on hearing measurements. These findings suggest that DBS does not hamper physiological processing in the auditory circuitry.

  20. Deep brain stimulation of globus pallidus interna, subthalamic nucleus, and pedunculopontine nucleus for Parkinson's disease: which target?

    Science.gov (United States)

    Follett, Kenneth A; Torres-Russotto, Diego

    2012-01-01

    Deep brain stimulation (DBS) is an accepted therapy for people with Parkinson's disease (PD) motor symptoms that are refractory to pharmacologic therapy. Standard DBS targets are globus pallidus interna (GPi) and subthalamic nucleus (STN). The pedunculopontine nucleus (PPN) is being investigated as a novel target. Which target provides the best outcomes is unknown. The utility of GPi and STN as targets has been confirmed in numerous studies, including randomized comparisons of GPi DBS and STN DBS that demonstrated no difference in motor outcomes. DBS at either site improves appendicular motor symptoms, but beneficial effects on axial manifestations of PD such as postural instability or gait dysfunction (PIGD) are less apparent. PPN has been introduced as a DBS target due to failure of GPi and STN DBS to improve PIGD. Small observational studies indicate improved PIGD with PPN DBS, but small blinded trials show only subjective reduction in falls with no other impact on PIGD or other PD manifestations. No single DBS target is superior to the others. Each target offers relative advantages. Further studies are needed to better define the roles of each target, particularly PPN. Choice of target should be individualized according to providers' preferences and patients' needs. Copyright © 2011 Elsevier Ltd. All rights reserved.

  1. Generalized folding model for elastic and inelastic nucleus-nucleus scattering using realistic density dependent nucleon-nucleon interaction

    CERN Document Server

    Khoa, D T

    2000-01-01

    A generalized double-folding model for elastic and inelastic nucleus-nucleus scattering is presented. It is designed to accommodate effective nucleon-nucleon (NN) interactions that depend upon the density of nuclear matter in which the two nucleons are immersed. A recently parametrized density dependent M3Y interaction, based on the G-matrix elements of the Paris NN potential, has been used in the present folding calculation. The effects of knock-on exchange of the interacting nucleon pair are included in an accurate local approximation. Examples of the application of this model to study the refractive elastic and inelastic scattering data of sup 1 sup 2 C+ sup 1 sup 2 C and alpha+ sup 5 sup 8 sup , sup 6 sup 0 Ni systems are presented. A detailed comparison of the use of deformed optical potential (DP) and microscopic folded potential in the analysis of inelastic scattering has shown that the use of DP fails to reproduce the inelastic sup 1 sup 2 C+ sup 1 sup 2 C scattering data measured over a wide angular ...

  2. The Spectator-Induced Electromagnetic Effect on Meson Production in Nucleus-Nucleus Collisions at SPS Energies

    Directory of Open Access Journals (Sweden)

    Rybicki Andrzej

    2012-12-01

    Full Text Available The electromagnetic interaction between the spectator system and the charged mesons produced in the course of the high energy heavy ion collision was studied experimentally and theoretically in earlier works [1,2]. This effect was found to result in very large distortions of the final state spectra of the produced mesons [3] and to bring new information on the space-time evolution of the non-perturbative meson production process [4]. In this paper a more extended analysis of this effect will be presented, including a comparative study between charged meson spectra produced in Pb+Pb collisions as well as collisions of Pb ions with smaller nuclei. The experimental results will be compared with Monte Carlo simulations, giving a fair overall understanding of the interplay between the strong and the electromagnetic interaction in the heavy ion collision. A universal behaviour of charged meson spectra emerges from the above comparative study. This gives a unique chance of using the spectator charge as a tool to study the space-time evolution of the high energy nucleus-nucleus reaction.

  3. Study of the Pion Production Mechanisms in Nucleus-Nucleus Collisions at the CERN SC using the Omicron Spectrometer

    CERN Multimedia

    2002-01-01

    The aim of this experiment is to study the pion production mechanism in nucleus-nucleus collisions with the |3He and |1|2C beams of the CERN SC using the Omicron Spectrometer. The high intensity ion beams delivered now by the SC combined with the favourable characteristics of the Omicron Spectrometer offer a unique possibility of measuring very low cross-sections (typically in the order of 1 pb/(sr~MeV/c). In a first stage we will measure with an energy resolution of about 3~MeV the spectra of @p@+ emitted at 0|0 in two-body reactions induced by |3He ions of 910~MeV on targets of |6Li, |7Li, |9Be and |1|2C. The aim is to understand the reaction mechanisms and the nuclear wave functions most appropriate to describe the formation of nuclear bound states at momentum transfers of about 1.6@/1.7~GeV/c. The apparatus is shown in the figure. The same instrument will allow the measurement of the @p@+ inclusive spectra emitted at 0|0 after the interaction of the |1|2C|4|+ beam at 1032 MeV with the same targets. At 86 ...

  4. Tone Recognition of Continuous Mandarin Speech Based on Tone Nucleus Model and Neural Network

    Science.gov (United States)

    Wang, Xiao-Dong; Hirose, Keikichi; Zhang, Jin-Song; Minematsu, Nobuaki

    A method was developed for automatic recognition of syllable tone types in continuous speech of Mandarin by integrating two techniques, tone nucleus modeling and neural network classifier. The tone nucleus modeling considers a syllable F0 contour as consisting of three parts: onset course, tone nucleus, and offset course. Two courses are transitions from/to neighboring syllable F0 contours, while the tone nucleus is intrinsic part of the F0 contour. By viewing only the tone nucleus, acoustic features less affected by neighboring syllables are obtained. When using the tone nucleus modeling, automatic detection of tone nucleus comes crucial. An improvement was added to the original detection method. Distinctive acoustic features for tone types are not limited to F0 contours. Other prosodic features, such as waveform power and syllable duration, are also useful for tone recognition. Their heterogeneous features are rather difficult to be handled simultaneously in hidden Markov models (HMM), but are easy in neural networks. We adopted multi-layer perception (MLP) as a neural network. Tone recognition experiments were conducted for speaker dependent and independent cases. In order to show the effect of integration, experiments were conducted also for two baselines: HMM classifier with tone nucleus modeling, and MLP classifier viewing entire syllable instead of tone nucleus. The integrated method showed 87.1% of tone recognition rate in speaker dependent case, and 80.9% in speaker independent case, which was about 10% relative error reduction as compared to the baselines.

  5. IDENTIFICATION OF VESTIBULOOCULAR PROJECTION NEURONS IN THE DEVELOPING CHICKEN MEDIAL VESTIBULAR NUCLEUS

    Science.gov (United States)

    Gottesman-Davis, Adria; Peusner, Kenna D.

    2010-01-01

    Biocytin was injected into the oculomotor, trochlear, or abducens nucleus on one side using isolated chicken brainstem preparations or brain slices to identify the medial vestibular nucleus (MVN) neurons projecting to these targets. Oculomotor nucleus injections produced retrogradely labeled neurons in the contralateral ventrolateral MVN (MVNVL), with few labeled neurons in the ipsilateral MVNVL, and rarely in the dorsomedial MVN on either side. Labeled MVNVL neurons were identified as stellate (95%) and elongate cells (5%). Trochlear nucleus injections produced a similar pattern of MVN neuron labeling. Abducens nucleus injections resulted in retrogradely labeled stellate (87%) and elongate (13%) neurons in the MVNVL which had smaller cell bodies than those projecting to the oculomotor nucleus. Anteroposteriorly, labeled MVNVL neurons were coextensive with the tangential nucleus, with neurons projecting to the oculomotor nucleus distributed lateral to and intermixed with the more medially situated neurons projecting to the abducens nucleus. The fundamental pattern of vestibuloocular projecting neurons was similar at both embryonic ages studied, E16 and E13. In contrast to mammals, where most vestibuloocular projection neurons reside within the MVN, the majority of retrogradely labeled neurons in these chicken preparations were found within the ventrolateral vestibular, descending vestibular, and tangential nuclei. The morphological identification and mapping of vestibuloocular projection neurons in the chicken MVN described here represents the first step in a systematic evaluation of the relationship between avian vestibuloocular neuron structure and function. PMID:19705454

  6. Shape Memory Alloys Application: Trailing Edge Shape Control

    National Research Council Canada - National Science Library

    Berton, Benoit

    2006-01-01

    .... A demonstrator of this adaptive trailing edge has been designed and manufactured. An original actuation concept has been developed based on a mixed system made of push-pull SMA (Shape Memory Alloy...

  7. A theory of shape identification

    CERN Document Server

    Cao, Frédéric; Morel, Jean-Michel; Musé, Pablo; Sur, Frédéric

    2008-01-01

    Recent years have seen dramatic progress in shape recognition algorithms applied to ever-growing image databases. They have been applied to image stitching, stereo vision, image mosaics, solid object recognition and video or web image retrieval. More fundamentally, the ability of humans and animals to detect and recognize shapes is one of the enigmas of perception. The book describes a complete method that starts from a query image and an image database and yields a list of the images in the database containing shapes present in the query image. A false alarm number is associated to each detection. Many experiments will show that familiar simple shapes or images can reliably be identified with false alarm numbers ranging from 10-5 to less than 10-300. Technically speaking, there are two main issues. The first is extracting invariant shape descriptors from digital images. The second is deciding whether two shape descriptors are identifiable as the same shape or not. A perceptual principle, the Helmholtz princi...

  8. Premeiotic microsporocyte cell shape influences shape of tetrads during microsporogenesis

    OpenAIRE

    Penet, Laurent

    2012-01-01

    Angiosperm microspores are grouped into tetrads before they mature into functional pollen grains. This tetrad stage is an important step in microsporogenesis. Tetrad shapes are diverse across angiosperms, with high levels of variation sometimes occurring within species, reflecting variation in early developmental events of nuclear and cell division (i.e., meiosis and cytokinesis). Among these developmental influences, the shape of the microsporocyte (pollen mother cell; hereafter PMC) is like...

  9. Morphological and physiological characteristics of laminar cells in the central nucleus of the inferior colliculus

    Directory of Open Access Journals (Sweden)

    Mark Nelson Wallace

    2012-08-01

    Full Text Available The central nucleus of the inferior colliculus (IC is organized into a series of fibro-dendritic laminae, orthogonal to the tonotopic progression. Many neurones have their dendrites confined to one lamina while others have dendrites that cross over a number of laminae. Here, we have used juxtacellular labelling in urethane anaesthetised guinea pigs to visualise the cells with biocytin and have analysed their response properties, in order to try and link their structure and function.Out of a sample of 38 filled cells, 15 had dendrites confined within the fibrodendritic laminae and in 13 we were also able to reconstruct their local axonal tree. Based on dendritic morphology they were subdivided into flat or less-flat; small, medium or large; elongated or disc-shaped cells. Two of the elongated cells had many dendritic spines while the other cells had few or none. Twelve of the cells had their local axonal tree restricted to the same lamina as their dendrites while one cell had its dendrites in a separate lamina from the axon. The axonal plexus was more extensive (width 0.7 – 1.4 mm within the lamina than the dendrites (width generally 0.07 – 0.53 mm. The intrinsic axons were largely confined to a single lamina within the central nucleus, but at least half the cells also had output axons with two heading for the commissure and 5 heading into the brachium. We were able to identify similarities in the physiological response profiles of small groups of our filled cells but none appeared to represent a homogeneous morphological cell type. The only common feature of our sample was one of exclusion in that the onset response, a response commonly recorded from IC cells, was never seen in laminar cells, but was in cells with a stellate morphology. Thus cells with laminar dendrites have a wide variety of physiological responses and morphological subtypes, but over 90% have an extensive local axonal tree within their local lamina.

  10. The earth's shape and gravity

    CERN Document Server

    Garland, G D; Wilson, J T

    2013-01-01

    The Earth's Shape and Gravity focuses on the progress of the use of geophysical methods in investigating the interior of the earth and its shape. The publication first offers information on gravity, geophysics, geodesy, and geology and gravity measurements. Discussions focus on gravity measurements and reductions, potential and equipotential surfaces, absolute and relative measurements, and gravity networks. The text then elaborates on the shape of the sea-level surface and reduction of gravity observations. The text takes a look at gravity anomalies and structures in the earth's crust; interp

  11. The suprachiasmatic nucleus: age-related decline in biological rhythms.

    Science.gov (United States)

    Nakamura, Takahiro J; Takasu, Nana N; Nakamura, Wataru

    2016-09-01

    Aging is associated with changes in sleep duration and quality, as well as increased rates of pathologic/disordered sleep. While several factors contribute to these changes, emerging research suggests that age-related changes in the mammalian central circadian clock within the suprachiasmatic nucleus (SCN) may be a key factor. Prior work from our group suggests that circadian output from the SCN declines because of aging. Furthermore, we have previously observed age-related infertility in female mice, caused by a mismatch between environmental light-dark cycles and the intrinsic, internal biological clocks. In this review, we address regulatory mechanisms underlying circadian rhythms in mammals and summarize recent literature describing the effects of aging on the circadian system.

  12. A syndrome of the dentate nucleus mimicking psychogenic ataxia.

    Science.gov (United States)

    Salih, Farid; Breuer, Eva; Harnack, Daniel; Hoffmann, Karl-Titus; Ploner, Christoph J

    2010-03-15

    To date, cerebellar involvement in control of non-motor functions like cognition and emotion is increasingly well established. Current models suggest that motor and non-motor networks connecting the cerebellum with cortical areas operate independently in closed and segregated loops. Here, we report a 59-year-old female patient with a small cerebellar lesion that shows that cognitive activation can significantly influence cerebellar motor control. Surprisingly, this led to a clinical picture mimicking a psychogenic disorder. Similar to non-human primates, this case suggests that the human dentate nucleus consists of distinct cognitive and motor domains with additional somatotopical arrangement of the latter. Extending current models of cerebro-cerebellar interaction, this case further illustrates that there can be significant functional cross-talk between motor and cognitive cerebellar networks.

  13. Relativistic models for quasielastic electron and neutrino-nucleus scattering

    Directory of Open Access Journals (Sweden)

    Meucci Andrea

    2012-12-01

    Full Text Available Relativistic models developed within the framework of the impulse approximation for quasielastic (QE electron scattering and successfully tested in comparison with electron-scattering data have been extended to neutrino-nucleus scattering. Different descriptions of final-state interactions (FSI in the inclusive scattering are compared. In the relativistic Green’s function (RGF model FSI are described consistently with the exclusive scattering using a complex optical potential. In the relativistic mean field (RMF model FSI are described by the same RMF potential which gives the bound states. The results of the models are compared for electron and neutrino scattering and, for neutrino scattering, with the recently measured charged-current QE (CCQE MiniBooNE cross sections.

  14. Observation of Top Quark Production in Proton-Nucleus Collisions.

    Science.gov (United States)

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    2017-12-15

    The first observation of top quark production in proton-nucleus collisions is reported using proton-lead data collected by the CMS experiment at the CERN LHC at a nucleon-nucleon center-of-mass energy of sqrt[s_{NN}]=8.16  TeV. The measurement is performed using events with exactly one isolated electron or muon candidate and at least four jets. The data sample corresponds to an integrated luminosity of 174  nb^{-1}. The significance of the tt[over ¯] signal against the background-only hypothesis is above 5 standard deviations. The measured cross section is σ_{tt[over ¯]}=45±8  nb, consistent with predictions from perturbative quantum chromodynamics.

  15. Static negative capacitance of a ferroelectric nano-domain nucleus

    Science.gov (United States)

    Sluka, Tomas; Mokry, Pavel; Setter, Nava

    2017-10-01

    Miniaturization of conventional field effect transistors (FETs) approaches the fundamental limits beyond which opening and closing the transistor channel require higher gate voltage swing and cause higher power dissipation and heating. This problem could be eliminated by placing a ferroelectric layer between the FET gate electrode and the channel, which effectively amplifies the gate voltage. The original idea of using a bulk ferroelectric negative capacitor suffers however from irreversible multi-domain ferroelectric switching, which does not allow us to stabilize static negative capacitance, while a recent reversible solution with super-lattices may be difficult to integrate onto FET. Here, we introduce a solution which provides static negative capacitance from a nano-domain nucleus. Phase-field simulations confirm the robustness of this concept, the conveniently achievable small effective negative capacitance and the potentially high compatibility of such a negative nano-capacitor with FET technology.

  16. Synaptic Plasticity in the Nucleus Accumbens: Lessons Learned from Experience.

    Science.gov (United States)

    Turner, Brandon D; Kashima, Daniel T; Manz, Kevin M; Grueter, Carrie A; Grueter, Brad A

    2018-01-24

    Synaptic plasticity contributes to behavioral adaptations. As a key node in the reward pathway, the nucleus accumbens (NAc) is important for determining motivation-to-action outcomes. Across animal models of motivation including addiction, depression, anxiety, and hedonic feeding, selective recruitment of neuromodulatory signals and plasticity mechanisms have been a focus of physiologists and behaviorists alike. Experience-dependent plasticity mechanisms within the NAc vary depending on the distinct afferents and cell-types over time. A greater understanding of molecular mechanisms determining how these changes in synaptic strength track with behavioral adaptations will provide insight into the process of learning and memory along with identifying maladaptations underlying pathological behavior. Here, we summarize recent findings detailing how changes in NAc synaptic strength and mechanisms of plasticity manifest in various models of motivational disorders.

  17. Skewering the subthalamic nucleus via a parietal approach.

    Science.gov (United States)

    Zrinzo, Ludvic; Holl, Etienne M; Petersen, Erika A; Limousin, Patricia; Foltynie, Thomas; Hariz, Marwan I

    2011-01-01

    A frontal burr hole around the level of the coronal suture is the conventional entry point when performing subthalamic nucleus (STN) deep brain stimulation (DBS). However, alternative approaches may sometimes be necessary. We present a report of delayed hardware erosion through the scalp in the left frontal region after successful bilateral STN DBS for Parkinson's disease. The left STN was retargeted via a parietal entry point. Significant improvement in UPDRS motor score (59%) was obtained with bilateral stimulation 6 months after re-operation. The literature was examined for similar approaches and the rationale, risks and benefits of non-frontal entry points in functional neurosurgery were explored. Together with a brief review of STN anatomy, this report demonstrates that the parietal approach to the STN remains a viable option in addition to the more traditional frontal access. Copyright © 2011 S. Karger AG, Basel.

  18. The LHC as a Proton-Nucleus Collider

    CERN Document Server

    Carli, C

    2006-01-01

    Following its initial operation as a proton-proton (p-p) and heavy-ion (208Pb82+-208Pb82+) collider, the LHC is expected to operate as a p-Pb collider. Later it may collide protons with other lighter nuclei such as 40Ar18+ or 16O8+. We show how the existing proton and lead-ion injector chains may be efficiently operated in tandem to provide these hybrid collisions. The two-in-one magnet design of the LHC main rings imposes different revolution frequencies for the two beams in part of the magnetic cycle. We discuss and evaluate the consequences for beam dynamics and estimate the potential performance of the LHC as a proton-nucleus collider.

  19. Observation of top quark production in proton-nucleus collisions

    Energy Technology Data Exchange (ETDEWEB)

    Sirunyan, Albert M; et al.

    2017-09-21

    The first observation of top quark production in proton-nucleus collisions is reported using proton-lead data collected by the CMS experiment at the CERN LHC at a nucleon-nucleon center-of-mass energy of $\\sqrt{s_\\mathrm{NN}} =$ 8.16 TeV. The measurement is performed using events with exactly one isolated electron or muon and at least four jets. The data sample corresponds to an integrated luminosity of 174 nb$^{-1}$. The significance of the $\\mathrm{t}\\overline{\\mathrm{t}}$ signal against the background-only hypothesis is above five standard deviations. The measured cross section is $\\sigma_{\\mathrm{t}\\overline{\\mathrm{t}}} =$ 45$\\pm$8 nb, consistent with predictions from perturbative quantum chromodynamics.

  20. Input/output properties of the lateral vestibular nucleus

    Science.gov (United States)

    Boyle, R.; Bush, G.; Ehsanian, R.

    2004-01-01

    This article is a review of work in three species, squirrel monkey, cat, and rat studying the inputs and outputs from the lateral vestibular nucleus (LVN). Different electrophysiological shock paradigms were used to determine the synaptic inputs derived from thick to thin diameter vestibular nerve afferents. Angular and linear mechanical stimulations were used to activate and study the combined and individual contribution of inner ear organs and neck afferents. The spatio-temporal properties of LVN neurons in the decerebrated rat were studied in response to dynamic acceleration inputs using sinusoidal linear translation in the horizontal head plane. Outputs were evaluated using antidromic identification techniques and identified LVN neurons were intracellularly injected with biocytin and their morphology studied.

  1. Reward and reinforcement activity in the nucleus accumbens during learning

    Directory of Open Access Journals (Sweden)

    John Thomas Gale

    2014-04-01

    Full Text Available The nucleus accumbens core (NAcc has been implicated in learning associations between sensory cues and profitable motor responses. However, the precise mechanisms that underlie these functions remain unclear. We recorded single-neuron activity from the NAcc of primates trained to perform a visual-motor associative learning task. During learning, we found two distinct classes of NAcc neurons. The first class demonstrated progressive increases in firing rates at the go-cue, feedback/tone and reward epochs of the task, as novel associations were learned. This suggests that these neurons may play a role in the exploitation of rewarding behaviors. In contrast, the second class exhibited attenuated firing rates, but only at the reward epoch of the task. These findings suggest that some NAcc neurons play a role in reward-based reinforcement during learning.

  2. Nuclear receptors outside the nucleus: extranuclear signalling by steroid receptors

    Science.gov (United States)

    Levin, Ellis R.; Hammes, Stephen R.

    2017-01-01

    Steroid hormone receptors mediate numerous crucial biological processes and are classically thought to function as transcriptional regulators in the nucleus. However, it has been known for more than 50 years that steroids evoke rapid responses in many organs that cannot be explained by gene regulation. Mounting evidence indicates that most steroid receptors in fact exist in extranuclear cellular pools, including at the plasma membrane. This latter pool, when engaged by a steroid ligand, rapidly activates signals that affect various aspects of cellular biology. Research into the mechanisms of signalling instigated by extranuclear steroid receptor pools and how this extranuclear signalling is integrated with responses elicited by nuclear receptor pools provides novel understanding of steroid hormone signalling and its roles in health and disease. PMID:27729652

  3. One-pion production in neutrino-nucleus collisions

    Energy Technology Data Exchange (ETDEWEB)

    Hernández, E. [Departamento de Física Fundamental e IUFFyM, Universidad de Salamanca, E-37008 Salamanca (Spain); Nieves, J. [Instituto de Física Corpuscular (IFIC), Centro Mixto CSIC-Universidad de Valencia, Institutos de Investigación de Paterna, Apartado 22085, E-46071 Valencia (Spain); Vicente-Vacas, J. M. [Departamento de Física Teórica e IFIC, Centro Mixto Universidad de Valencia-CSIC, Institutos de Investigación de Paterna, Apartado 22085, E-46071 Valencia (Spain)

    2015-05-15

    We use our model for neutrino pion production on the nucleon to study pion production on a nucleus. The model is conveniently modified to include in-medium corrections and its validity is extended up to 2 GeV neutrino energies by the inclusion of new resonant contributions in the production process. Our results are compared with recent MiniBooNE data measured in mineral oil. Our total cross sections are below data for neutrino energies above ≈ 1 GeV. As with other theoretical calculations, the agreement with data improves if we neglect pion final state interaction. This is also the case for differential cross sections convoluted over the neutrino flux.

  4. Role of the nucleus in apoptosis: signaling and execution.

    Science.gov (United States)

    Prokhorova, Evgeniia A; Zamaraev, Alexey V; Kopeina, Gelina S; Zhivotovsky, Boris; Lavrik, Inna N

    2015-12-01

    Since their establishment in the early 1970s, the nuclear changes upon apoptosis induction, such as the condensation of chromatin, disassembly of nuclear scaffold proteins and degradation of DNA, were, and still are, considered as the essential steps and hallmarks of apoptosis. These are the characteristics of the execution phase of apoptotic cell death. In addition, accumulating data clearly show that some nuclear events can lead to the induction of apoptosis. In particular, if DNA lesions resulting from deregulation during the cell cycle or DNA damage induced by chemotherapeutic drugs or viral infection cannot be efficiently eliminated, apoptotic mechanisms, which enable cellular transformation to be avoided, are activated in the nucleus. The functional heterogeneity of the nuclear organization allows the tight regulation of these signaling events that involve the movement of various nuclear proteins to other intracellular compartments (and vice versa) to initiate and govern apoptosis. Here, we discuss how these events are coordinated to execute apoptotic cell death.

  5. The dolphin cochlear nucleus: topography, histology and functional implications.

    Science.gov (United States)

    Malkemper, E P; Oelschläger, H H A; Huggenberger, S

    2012-02-01

    Despite the outstanding auditory capabilities of dolphins, there is only limited information available on the cytology of the auditory brain stem nuclei in these animals. Here, we investigated the cochlear nuclei (CN) of five brains of common dolphins (Delphinus delphis) and La Plata dolphins (Pontoporia blainvillei) using cell and fiber stain microslide series representing the three main anatomical planes. In general, the CN in dolphins comprise the same set of subnuclei as in other mammals. However, the volume ratio of the dorsal cochlear nucleus (DCN) in relation to the ventral cochlear nucleus (VCN) of dolphins represents a minimum among the mammals examined so far. Because, for example, in cats the DCN is necessary for reflexive orientation of the head and pinnae towards a sound source, the massive restrictions in head movability in dolphins and the absence of outer ears may be correlated with the reduction of the DCN. Moreover, the same set of main neuron types were found in the dolphin CN as in other mammals, including octopus and multipolar cells. Because the latter two types of neurons are thought to be involved in the recognition of complex sounds, including speech, we suggest that, in dolphins, they may be involved in the processing of their communication signals. Comparison of the toothed whale species studied here revealed that large spherical cells were present in the La Plata dolphin but absent in the common dolphin. These neurons are known to be engaged in the processing of low-frequency sounds in terrestrial mammals. Accordingly, in the common dolphin, the absence of large spherical cells seems to be correlated with a shift of its auditory spectrum into the high-frequency range above 20 kHz. The existence of large spherical cells in the VCN of the La Plata dolphin, however, is enigmatic asthis species uses frequencies around 130 kHz. Copyright © 2011 Wiley Periodicals, Inc.

  6. Intrinsic properties and neuropharmacology of midline paraventricular thalamic nucleus neurons.

    Directory of Open Access Journals (Sweden)

    Miloslav eKolaj

    2014-04-01

    Full Text Available Neurons in the midline and intralaminar thalamic nuclei are components of an interconnected brainstem, limbic and prefrontal cortex neural network that is engaged during arousal, vigilance, motivated and addictive behaviors, and stress. To better understand the cellular mechanisms underlying these functions, here we review some of the recently characterized electrophysiological and neuropharmacological properties of neurons in the paraventricular thalamic nucleus (PVT, derived from whole cell patch clamp recordings in acute rat brain slice preparations. PVT neurons display firing patterns and ionic conductances (IT and IH that exhibit significant diurnal change. Their resting membrane potential is maintained by various ionic conductances that include inward rectifier (Kir, hyperpolarization-activated nonselective cation (HCN and TWIK-related acid sensitive (TASK K+ channels. Firing patterns are regulated by high voltage-activated (HVA and low voltage-activated (LVA Ca2+ conductances. Moreover, transient receptor potential (TRP-like nonselective cation channels together with Ca2+- and Na+-activated K+ conductances (KCa; KNa contribute to unique slow afterhyperpolarizing potentials (sAHPs that are generally not detectable in lateral thalamic or reticular thalamic nucleus neurons. We also report on receptor-mediated actions of GABA, glutamate, monoamines and several neuropeptides: arginine vasopressin, gastrin-releasing peptide, thyrotropin releasing hormone and the orexins (hypocretins. This review represents an initial survey of intrinsic and transmitter-sensitive ionic conductances that are deemed to be unique to this population of midline thalamic neurons, information that is fundamental to an appreciation of the role these thalamic neurons may play in normal central nervous system (CNS physiology and in CNS disorders that involve the dorsomedial thalamus.

  7. Subthalamic nucleus electrical stimulation modulates calcium activity of nigral astrocytes.

    Directory of Open Access Journals (Sweden)

    Elodie Barat

    Full Text Available BACKGROUND: The substantia nigra pars reticulata (SNr is a major output nucleus of the basal ganglia, delivering inhibitory efferents to the relay nuclei of the thalamus. Pathological hyperactivity of SNr neurons is known to be responsible for some motor disorders e.g. in Parkinson's disease. One way to restore this pathological activity is to electrically stimulate one of the SNr input, the excitatory subthalamic nucleus (STN, which has emerged as an effective treatment for parkinsonian patients. The neuronal network and signal processing of the basal ganglia are well known but, paradoxically, the role of astrocytes in the regulation of SNr activity has never been studied. PRINCIPAL FINDINGS: In this work, we developed a rat brain slice model to study the influence of spontaneous and induced excitability of afferent nuclei on SNr astrocytes calcium activity. Astrocytes represent the main cellular population in the SNr and display spontaneous calcium activities in basal conditions. Half of this activity is autonomous (i.e. independent of synaptic activity while the other half is dependent on spontaneous glutamate and GABA release, probably controlled by the pace-maker activity of the pallido-nigral and subthalamo-nigral loops. Modification of the activity of the loops by STN electrical stimulation disrupted this astrocytic calcium excitability through an increase of glutamate and GABA releases. Astrocytic AMPA, mGlu and GABA(A receptors were involved in this effect. SIGNIFICANCE: Astrocytes are now viewed as active components of neural networks but their role depends on the brain structure concerned. In the SNr, evoked activity prevails and autonomous calcium activity is lower than in the cortex or hippocampus. Our data therefore reflect a specific role of SNr astrocytes in sensing the STN-GPe-SNr loops activity and suggest that SNr astrocytes could potentially feedback on SNr neuronal activity. These findings have major implications given the

  8. Temporal Expression of Wnt1 Defines the Competency State and Terminal Identity of Progenitors in the Developing Cochlear Nucleus and Inferior Colliculus

    Directory of Open Access Journals (Sweden)

    Stephen Brown

    2017-08-01

    Full Text Available The auditory system contains a diverse array of interconnected anatomical structures that mediate the perception of sound. The cochlear nucleus of the hindbrain serves as the initial site of convergence for auditory stimuli, while the inferior colliculus of the midbrain serves as an integration and relay station for all ascending auditory information. We used Genetic Inducible Fate Mapping (GIFM to determine how the timing of Wnt1 expression is related to the competency states of auditory neuron progenitors. We demonstrate that the Wnt1 lineage defines progenitor pools of auditory neurons in the developing midbrain and hindbrain. The timing of Wnt1 expression specifies unique cell types during embryogenesis and follows a mixed model encompassing a brief epoch of de novo expression followed by rapid and progressive lineage restriction to shape the inferior colliculus. In contrast, Wnt1 fate mapping of the embryonic hindbrain revealed de novo induction of Wnt1 in auditory hindbrain progenitors, which is related to the development of biochemically distinct neurons in the cochlear nucleus. Thus, we uncovered two modes of lineage allocation that explain the relationship between the timing of Wnt1 expression and the development of the cochlear nucleus and the inferior colliculus. Finally, our analysis of Wnt1sw/sw mutant mice demonstrated a functional requirement of Wnt1 for the development of auditory midbrain and hindbrain neurons. Collectively, our study provides a deeper understanding of Wnt1 lineage allocation and function in mammalian brain development.

  9. GABAergic projections to the oculomotor nucleus in the goldfish (Carassius auratus

    Directory of Open Access Journals (Sweden)

    M. Angeles eLuque

    2011-02-01

    Full Text Available The mammalian oculomotor nucleus receives a strong -aminobutyric acid (GABAergic synaptic input, whereas such projections have rarely been reported in fish. In order to determine whether this synaptic organization is preserved across vertebrates, we investigated the GABAergic projections to the oculomotor nucleus in the goldfish by combining retrograde transport of biotin dextran amine, injected into the antidromically identified oculomotor nucleus, and GABA immunohistochemistry. The main source of GABAergic afferents to the oculomotor nucleus was the ipsilateral anterior octaval nucleus, with only a few, if any, GABAergic neurons being located in the contralateral tangential and descending nuclei of the octaval column. In mammals there is a nearly exclusive ipsilateral projection from vestibular neurons to the oculomotor nucleus via GABAergic inhibitory inputs; thus, the vestibulooculomotor GABAergic circuitry follows a plan that appears to be shared throughout the vertebrate phylogeny. The second major source of GABAergic projections was the rhombencephalic reticular formation, primarily from the medial area but, to a lesser extent, from the inferior area. A few GABAergic oculomotor projecting neurons were also observed in the ipsilateral nucleus of the medial longitudinal fasciculus. The GABAergic projections from neurons located in both the reticular formation surrounding the abducens nucleus and the nucleus of the medial reticular formation have primarily been related to the control of saccadic eye movements. Finally, all retrogradely labeled internuclear neurons of the abducens nucleus, and neurons in the cerebellum (close to the caudal lobe, were negative for GABA. These data suggest that the vestibuloocular and saccadic inhibitory GABAergic systems appear early in vertebrate phylogeny to modulate the firing properties of the oculomotor nucleus motoneurons.

  10. Aging changes in body shape

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003998.htm Aging changes in body shape To use the sharing ... and both sexes. Height loss is related to aging changes in the bones, muscles, and joints. People ...

  11. Magnetic shape memory: Magnetoelastic sponges

    Science.gov (United States)

    Acet, Mehmet

    2009-11-01

    Nickel-manganese-gallium foams connected internally by sizeable single-crystalline elements provide magnetic-field-induced strains comparable to free-standing bulk single crystals, and demonstrate feasibility for the application of magnetic shape memory.

  12. Nuclear Shape, Mechanics, and Mechanotransduction

    National Research Council Canada - National Science Library

    Dahl, Kris Noel; Ribeiro, Alexandre J.S; Lammerding, Jan

    2008-01-01

    .... Here, we discuss the effect of intra- and extracellular forces on nuclear shape and structure and how these force-induced changes could be implicated in nuclear mechanotransduction, ie, force-induced...

  13. S-shaped learning curves.

    Science.gov (United States)

    Murre, Jaap M J

    2014-04-01

    In this article, learning curves for foreign vocabulary words are investigated, distinguishing between a subject-specific learning rate and a material-specific parameter that is related to the complexity of the items, such as the number of syllables. Two experiments are described, one with Turkish words and one with Italian words. In both, S-shaped learning curves were observed, which were most obvious if the subjects were not very familiar with the materials and if they were slow learners. With prolonged learning, the S shapes disappeared. Three different mathematical functions are proposed to explain these S-shaped curves. A further analysis clarifies why S-shaped learning curves may go unnoticed in many experiments.

  14. Shape-Morphing Nanocomposite Origami

    Science.gov (United States)

    2015-01-01

    Nature provides a vast array of solid materials that repeatedly and reversibly transform in shape in response to environmental variations. This property is essential, for example, for new energy-saving technologies, efficient collection of solar radiation, and thermal management. Here we report a similar shape-morphing mechanism using differential swelling of hydrophilic polyelectrolyte multilayer inkjets deposited on an LBL carbon nanotube (CNT) composite. The out-of-plane deflection can be precisely controlled, as predicted by theoretical analysis. We also demonstrate a controlled and stimuli-responsive twisting motion on a spiral-shaped LBL nanocomposite. By mimicking the motions achieved in nature, this method offers new opportunities for the design and fabrication of functional stimuli-responsive shape-morphing nanoscale and microscale structures for a variety of applications. PMID:24689908

  15. Corticotropin-releasing factor within the central nucleus of the amygdala and the nucleus accumbens shell mediates the negative affective state of nicotine withdrawal in rats

    OpenAIRE

    Marcinkiewcz, Catherine A.; Prado, Melissa M.; Isaac, Shani K.; Marshall, Alex.; Rylkova, Daria; Bruijnzeel, Adrie W.

    2009-01-01

    Tobacco addiction is a chronic disorder that is characterized by a negative affective state upon smoking cessation and relapse after periods of abstinence. Previous research has shown that an increased central release of corticotropin-releasing factor (CRF) at least partly mediates the deficit in brain reward function associated with nicotine withdrawal in rats. The aim of these studies was to investigate the role of CRF in the central nucleus of the amygdala (CeA), the lateral bed nucleus of...

  16. Electrochromic fiber-shaped supercapacitors.

    Science.gov (United States)

    Chen, Xuli; Lin, Huijuan; Deng, Jue; Zhang, Ye; Sun, Xuemei; Chen, Peining; Fang, Xin; Zhang, Zhitao; Guan, Guozhen; Peng, Huisheng

    2014-12-23

    An electrochromic fiber-shaped super-capacitor is developed by winding aligned carbon nanotube/polyaniline composite sheets on an elastic fiber. The fiber-shaped supercapacitors demonstrate rapid and reversible chromatic transitions under different working states, which can be directly observed by the naked eye. They are also stretchable and flexible, and are woven into textiles to display designed signals in addition to storing energy. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. ESR powder line shape calculations

    Energy Technology Data Exchange (ETDEWEB)

    Vitko, J. Jr.; Huddleston, R.E.

    1976-05-01

    A program has been developed for computing the ESR spectrum of a collection of randomly oriented spins subject only to an electronic Zeeman interaction and having a Lorentzian single crystal line shape. Other single crystal line shapes, including numerical solutions of the Bloch equations, can be accommodated with minor modifications. The program differs in several features from those existing elsewhere, thus enabling one to study saturation effects, over-modulation effects, both absorptive and dispersive signals, and second and higher order derivative signals.

  18. NONCONVEX REGULARIZATION FOR SHAPE PRESERVATION

    Energy Technology Data Exchange (ETDEWEB)

    CHARTRAND, RICK [Los Alamos National Laboratory

    2007-01-16

    The authors show that using a nonconvex penalty term to regularize image reconstruction can substantially improve the preservation of object shapes. The commonly-used total-variation regularization, {integral}|{del}u|, penalizes the length of the object edges. They show that {integral}|{del}u|{sup p}, 0 < p < 1, only penalizes edges of dimension at least 2-p, and thus finite-length edges not at all. We give numerical examples showing the resulting improvement in shape preservation.

  19. Interactive online brain shape visualization

    Directory of Open Access Journals (Sweden)

    Anisha Keshavan

    2017-02-01

    Full Text Available The open-source Mindboggle package improves the labeling and morphometry estimates of brain imaging data. At the 2015 Brainhack event, we developed a web-based, interactive, brain shape visualization of Mindboggle outputs. The application links a 3D brain visualization with boxplots that describe shape measures across a selected cortical label. The code is freely available at http://www.github.com/akeshavan/roygbiv and a demo is online at http://roygbiv.mindboggle.info.

  20. Detecting shapes in noise: tuning characteristics of global shape mechanisms

    Science.gov (United States)

    Schmidtmann, Gunnar; Gordon, Gael E.; Bennett, David M.; Loffler, Gunter

    2013-01-01

    The proportion of signal elements embedded in noise needed to detect a signal is a standard tool for investigating motion perception. This paradigm was applied to the shape domain to determine how local information is pooled into a global percept. Stimulus arrays consisted of oriented Gabor elements that sampled the circumference of concentric radial frequency (RF) patterns. Individual Gabors were oriented tangentially to the shape (signal) or randomly (noise). In different conditions, signal elements were located randomly within the entire array or constrained to fall along one of the concentric contours. Coherence thresholds were measured for RF patterns with various frequencies (number of corners) and amplitudes (“sharpness” of corners). Coherence thresholds (about 10% = 15 elements) were lowest for circular shapes. Manipulating shape frequency or amplitude showed a range where thresholds remain unaffected (frequency ≤ RF4; amplitude ≤ 0.05). Increasing either parameter caused thresholds to rise. Compared to circles, thresholds increased by approximately four times for RF13 and five times for amplitudes of 0.3. Confining the signals to individual contours significantly reduced the number of elements needed to reach threshold (between 4 and 6), independent of the total number of elements on the contour or contour shape. Finally, adding external noise to the orientation of the elements had a greater effect on detection thresholds than adding noise to their position. These results provide evidence for a series of highly sensitive, shape-specific analysers which sum information globally but only from within specific annuli. These global mechanisms are tuned to position and orientation of local elements from which they pool information. The overall performance for arrays of elements can be explained by the sensitivity of multiple, independent concentric shape detectors rather than a single detector integrating information widely across space (e.g. Glass

  1. Bayesian Vision for Shape Recovery

    Science.gov (United States)

    Jalobeanu, Andre

    2004-01-01

    We present a new Bayesian vision technique that aims at recovering a shape from two or more noisy observations taken under similar lighting conditions. The shape is parametrized by a piecewise linear height field, textured by a piecewise linear irradiance field, and we assume Gaussian Markovian priors for both shape vertices and irradiance variables. The observation process. also known as rendering, is modeled by a non-affine projection (e.g. perspective projection) followed by a convolution with a piecewise linear point spread function. and contamination by additive Gaussian noise. We assume that the observation parameters are calibrated beforehand. The major novelty of the proposed method consists of marginalizing out the irradiances considered as nuisance parameters, which is achieved by Laplace approximations. This reduces the inference to minimizing an energy that only depends on the shape vertices, and therefore allows an efficient Iterated Conditional Mode (ICM) optimization scheme to be implemented. A Gaussian approximation of the posterior shape density is computed, thus providing estimates both the geometry and its uncertainty. We illustrate the effectiveness of the new method by shape reconstruction results in a 2D case. A 3D version is currently under development and aims at recovering a surface from multiple images, reconstructing the topography by marginalizing out both albedo and shading.

  2. NPY and VGF Immunoreactivity Increased in the Arcuate Nucleus, but Decreased in the Nucleus of the Tractus Solitarius, of Type-II Diabetic Patients

    Science.gov (United States)

    Saderi, Nadia; Salgado-Delgado, Roberto; Avendaño-Pradel, Rafael; Basualdo, Maria del Carmen; Ferri, Gian-Luca; Chávez-Macías, Laura; Escobar, Carolina; Buijs, Ruud M.

    2012-01-01

    Ample animal studies demonstrate that neuropeptides NPY and α-MSH expressed in Arcuate Nucleus and Nucleus of the Tractus Solitarius, modulate glucose homeostasis and food intake. In contrast is the absence of data validating these observations for human disease. Here we compare the post mortem immunoreactivity of the metabolic neuropeptides NPY, αMSH and VGF in the infundibular nucleus, and brainstem of 11 type-2 diabetic and 11 non-diabetic individuals. α-MSH, NPY and tyrosine hydroxylase in human brain are localized in the same areas as in rodent brain. The similar distribution of NPY, α-MSH and VGF indicated that these neurons in the human brain may share similar functionality as in the rodent brain. The number of NPY and VGF immuno positive cells was increased in the infundibular nucleus of diabetic subjects in comparison to non-diabetic controls. In contrast, NPY and VGF were down regulated in the Nucleus of the Tractus Solitarius of diabetic patients. These results suggest an activation of NPY producing neurons in the arcuate nucleus, which, according to animal experimental studies, is related to a catabolic state and might be the basis for increased hepatic glucose production in type-2 diabetes. PMID:22808091

  3. Input-output organization of inhibitory neurons in the interstitial nucleus of Cajal projecting to the contralateral trochlear and oculomotor nucleus.

    Science.gov (United States)

    Sugiuchi, Y; Takahashi, M; Shinoda, Y

    2013-08-01

    Neurons in the interstitial nucleus of Cajal (INC) that are known to be involved in eye and head movements are excitatory. We investigated the input-output organization of inhibitory INC neurons involved in controlling vertical saccades. Intracellular recordings were made in INC neurons activated antidromically by stimulation of the contralateral trochlear or oculomotor nucleus, and their synaptic input properties from the superior colliculi (SCs) and the contralateral INC were analyzed in anesthetized cats. Many INC neurons projected to the contralateral trochlear nucleus, Forel's field H, INC, and oculomotor nucleus, and mainly received monosynaptic excitation followed by disynaptic inhibition from the ipsi- and contralateral SCs. After sectioning the commissural connections between the SCs, these neurons received monosynaptic excitation from the ipsilateral medial SC and disynaptic inhibition via the INC from the contralateral lateral SC. Another group of INC neurons were antidromically activated from the contralateral oculomotor nucleus, INC and Forel's field H, but not from the trochlear nucleus, and received monosynaptic excitation from the ipsilateral lateral SC and disynaptic inhibition from the contralateral medial SC. The former group was considered to inhibit contralateral trochlear and inferior rectus motoneurons in upward saccades, whereas the latter was considered to inhibit contralateral superior rectus and inferior oblique motoneurons in downward saccades. The mutual inhibition existed between these two groups of INC neurons for upward saccades on one side and downward saccades on the other. This pattern of input-output organization of inhibitory INC neurons suggests that the basic neural circuits for horizontal and vertical saccades are similar.

  4. Shape analysis in medical image analysis

    CERN Document Server

    Tavares, João

    2014-01-01

    This book contains thirteen contributions from invited experts of international recognition addressing important issues in shape analysis in medical image analysis, including techniques for image segmentation, registration, modelling and classification, and applications in biology, as well as in cardiac, brain, spine, chest, lung and clinical practice. This volume treats topics such as, anatomic and functional shape representation and matching; shape-based medical image segmentation; shape registration; statistical shape analysis; shape deformation; shape-based abnormity detection; shape tracking and longitudinal shape analysis; machine learning for shape modeling and analysis; shape-based computer-aided-diagnosis; shape-based medical navigation; benchmark and validation of shape representation, analysis and modeling algorithms. This work will be of interest to researchers, students, and manufacturers in the fields of artificial intelligence, bioengineering, biomechanics, computational mechanics, computationa...

  5. Redistribution of particles across the nucleus of comet 67P/Churyumov-Gerasimenko

    Science.gov (United States)

    Thomas, N.; Davidsson, B.; El-Maarry, M. R.; Fornasier, S.; Giacomini, L.; Gracia-Berná, A. G.; Hviid, S. F.; Ip, W.-H.; Jorda, L.; Keller, H. U.; Knollenberg, J.; Kührt, E.; La Forgia, F.; Lai, I. L.; Liao, Y.; Marschall, R.; Massironi, M.; Mottola, S.; Pajola, M.; Poch, O.; Pommerol, A.; Preusker, F.; Scholten, F.; Su, C. C.; Wu, J. S.; Vincent, J.-B.; Sierks, H.; Barbieri, C.; Lamy, P. L.; Rodrigo, R.; Koschny, D.; Rickman, H.; A'Hearn, M. F.; Barucci, M. A.; Bertaux, J.-L.; Bertini, I.; Cremonese, G.; Da Deppo, V.; Debei, S.; de Cecco, M.; Fulle, M.; Groussin, O.; Gutierrez, P. J.; Kramm, J.-R.; Küppers, M.; Lara, L. M.; Lazzarin, M.; Lopez Moreno, J. J.; Marzari, F.; Michalik, H.; Naletto, G.; Agarwal, J.; Güttler, C.; Oklay, N.; Tubiana, C.

    2015-11-01

    Context. We present an investigation of the surface properties of areas on the nucleus of comet 67P/Churyumov-Gerasimenko. Aims: We aim to show that transport of material from one part of the cometary nucleus to another is a significant mechanism that influences the appearance of the nucleus and the surface thermal properties. Methods: We used data from the OSIRIS imaging system onboard the Rosetta spacecraft to identify surface features on the nucleus that can be produced by various transport mechanisms. We used simple calculations based on previous works to establish the plausibility of dust transport from one part of the nucleus to another. Results: We show by observation and modeling that "airfall" as a consequence of non-escaping large particles emitted from the neck region of the nucleus is a plausible explanation for the smooth thin deposits in the northern hemisphere of the nucleus. The consequences are also discussed. We also present observations of aeolian ripples and ventifacts. We show by numerical modeling that a type of saltation is plausible even under the rarified gas densities seen at the surface of the nucleus. However, interparticle cohesive forces present difficulties for this model, and an alternative mechanism for the initiation of reptation and creep may result from the airfall mechanism. The requirements on gas density and other parameters of this alternative make it a more attractive explanation for the observations. The uncertainties and implications are discussed.

  6. Prospects for measuring coherent neutrino-nucleus elastic scattering at a stopped-pion neutrino source

    OpenAIRE

    Scholberg, Kate

    2005-01-01

    Rates of coherent neutrino-nucleus elastic scattering at a high-intensity stopped-pion neutrino source in various detector materials (relevant for novel low-threshold detectors) are calculated. Sensitivity of a coherent neutrino-nucleus elastic scattering experiment to new physics is also explored.

  7. The performance of a hydrogel nucleus pulposus prosthesis in an ex vivo canine model

    NARCIS (Netherlands)

    Bergknut, N.; Smolders, L.A.; Koole, L.H.; Voorhout, G.; Hagman, R.E.; Lagerstedt, A.S.; Saralidze, K.; Hazewinkel, H.A.W.; van der Veen, A.J.; Meij, B.P.

    2010-01-01

    A nucleus pulposus prosthesis (NPP) made of the hydrogel N-vinyl-2-pyrrolidinone copolymerized with 2-(4'-iodobenzoyl)-oxo-ethyl methacrylate has recently been developed. The special features of this NPP, i.e. intrinsic radiopacity and its ability to swell in situ to fill the nucleus cavity and

  8. Rotational structures in the odd-odd nucleus {sup 80}Y

    Energy Technology Data Exchange (ETDEWEB)

    Bucurescu, D. [Institutul de Fizica Atomica, Bucharest (Romania); Ur, C.A. [Institutul de Fizica Atomica, Bucharest (Romania); Bazzacco, D. [Istituto Nazionale di Fisica Nucleare, Padua (Italy)]|[Padua Univ. (Italy). Dipt. di Fisica; Rossi-Alvarez, C. [Istituto Nazionale di Fisica Nucleare, Padua (Italy)]|[Padua Univ. (Italy). Dipt. di Fisica; Spolaore, P. [Istituto Nazionale di Fisica Nucleare, Legnaro (Italy). Lab. Nazionali di Legnaro; Petrache, C.M. [Istituto Nazionale di Fisica Nucleare, Padua (Italy)]|[Padua Univ. (Italy). Dipt. di Fisica; Ionescu-Bujor, M. [Institutul de Fizica Atomica, Bucharest (Romania); Lunardi, S. [Istituto Nazionale di Fisica Nucleare, Padua (Italy)]|[Padua Univ. (Italy). Dipt. di Fisica; Medina, N.H. [Istituto Nazionale di Fisica Nucleare, Padua (Italy)]|[Padua Univ. (Italy). Dipt. di Fisica; Napoli, D.R. [Istituto Nazionale di Fisica Nucleare, Legnaro (Italy). Lab. Nazionali di Legnaro; De Poli, M. [Istituto Nazionale di Fisica Nucleare, Legnaro (Italy). Lab. Nazionali di Legnaro; De Angelis, G. [Istituto Nazionale di Fisica Nucleare, Legnaro (Italy). Lab. Nazionali di Legnaro; Brandolini, F. [Istituto Nazionale di Fisica Nucleare, Padua (Italy)]|[Padua Univ. (Italy). Dipt. di Fisica; Gadea, A. [Istituto Nazionale di Fisica Nucleare, Legnaro (Italy). Lab. Nazionali di Legnaro; Pavan, P. [Istituto Nazionale di Fisica Nucleare, Legnaro (Italy). Lab. Nazionali di Legnaro; Segato, G.F. [Istituto Nazionale di Fisica Nucleare, Padua (Italy)]|[Padua Univ. (Italy). Dipt. di Fisica

    1995-09-01

    High spin states have been observed for the first time in the odd-odd nucleus {sup 80}Y, by using the {sup 24}Mg({sup 58}Ni,pn) reaction at 180 MeV. Eight rotational bands have been established, indicating a nucleus with appreciable deformation. (orig.)

  9. Methods for the mineralogical and textural analysis of comet nucleus samples

    Science.gov (United States)

    Stoeffler, D.; Dueren, H.; Knoelker, J.

    1989-01-01

    The objectives and instrumental requirements of a petrographic analysis of porous comet nucleus material are reviewed. Assumptions about its composition and texture, and the available techniques for the microscopic analysis of comet analogue material are investigated. New techniques required for the petrographic investigation of natural and artificial comet nucleus samples are also considered.

  10. Dopamine efflux in nucleus accumbens shell and core in response to appetitive classical conditioning

    NARCIS (Netherlands)

    Cheng, J. J.; de Bruin, J. P. C.; Feenstra, M. G. P.

    2003-01-01

    Dopamine transmission within the nucleus accumbens has been implicated in associative reinforcement learning. We investigated the effect of appetitive classical conditioning on dopamine efflux in the rat nucleus accumbens shell and core, as dopamine may be differentially activated by conditioned and

  11. Three-Dimensional Organization of Chromosome Territories in the Human Interphase Nucleus

    NARCIS (Netherlands)

    T.A. Knoch (Tobias); J. Langowski (Jörg)

    1999-01-01

    textabstractDespite the successful linear sequencing of the human genome its three-dimensional structure is widely unknown. The regulation of genes has been shown to be connected closely to the three-dimensional organization of the genome in the cell nucleus. The nucleus of the cell has for a long

  12. The Stimulatory Effect of Notochordal Cell-Conditioned Medium in a Nucleus Pulposus Explant Culture

    NARCIS (Netherlands)

    de Vries, Stefan A H; van Doeselaar, Marina; Meij, Björn P; Tryfonidou, Marianna A; Ito, K|info:eu-repo/dai/nl/345809610

    2016-01-01

    Objectives: Notochordal cell-conditioned medium (NCCM) has previously shown to have a stimulatory effect on nucleus pulposus cells (NPCs) and bone marrow stromal cells (BMSCs) in alginate and pellet cultures. These culture methods provide a different environment than the nucleus pulposus (NP)

  13. The Stimulatory Effect of Notochordal-Cell Conditioned Medium in a Nucleus Pulposus Explant Culture

    NARCIS (Netherlands)

    de Vries, Stefan; Doeselaar, Marina van; Meij, Björn; Tryfonidou, M; Ito, Keita

    2015-01-01

    OBJECTIVES: Notochordal cell-conditioned medium (NCCM) has previously shown to have a stimulatory effect on nucleus pulposus cells (NPCs) and bone marrow stromal cells (BMSCs) in alginate and pellet cultures. These culture methods provide a different environment than the nucleus pulposus (NP)

  14. Whisker movements evoked by stimulation of single motor neurons in the facial nucleus of the rat

    NARCIS (Netherlands)

    L.J. Herfst (Lucas); M. Brecht (Michael)

    2008-01-01

    textabstractThe lateral facial nucleus is the sole output structure whose neuronal activity leads to whisker movements. To understand how single facial nucleus neurons contribute to whisker movement we combined single-cell stimulation and high-precision whisker tracking. Half of the 44 stimulated

  15. Non-compound nucleus fission in actinide and pre-actinide regions

    Indian Academy of Sciences (India)

    fragment angular distribution in 28Si+176Yb reaction did not show a large contribution from the non-compound nucleus fission. Data on the evaporation residue cross-sections, in addition to those on mass and angular distributions, are necessary for better understanding of the contribution from non-compound nucleus ...

  16. Protein Kinase C Epsilon Activity in the Nucleus Accumbens and Central Nucleus of the Amygdala Mediates Binge Alcohol Consumption.

    Science.gov (United States)

    Cozzoli, Debra K; Courson, Justin; Rostock, Charlotte; Campbell, Rianne R; Wroten, Melissa G; McGregor, Hadley; Caruana, Amanda L; Miller, Bailey W; Hu, Jia-Hua; Wu Zhang, Ping; Xiao, Bo; Worley, Paul F; Crabbe, John C; Finn, Deborah A; Szumlinski, Karen K

    2016-03-15

    Protein kinase C epsilon (PKCε) is emerging as a potential target for the development of pharmacotherapies to treat alcohol use disorders, yet little is known regarding how a history of a highly prevalent form of drinking, binge alcohol intake, influences enzyme priming or the functional relevance of kinase activity for excessive alcohol intake. Immunoblotting was employed on tissue from subregions of the nucleus accumbens (NAc) and the amygdala to examine both idiopathic and binge drinking-induced changes in constitutive PKCε priming. The functional relevance of PKCε translocation for binge drinking and determination of potential upstream signaling pathways involved were investigated using neuropharmacologic approaches within the context of two distinct binge drinking procedures, drinking in the dark and scheduled high alcohol consumption. Binge alcohol drinking elevated p(Ser729)-PKCε levels in both the NAc and the central nucleus of the amygdala (CeA). Moreover, immunoblotting studies of selectively bred and transgenic mouse lines revealed a positive correlation between the propensity to binge drink alcohol and constitutive p(Ser729)-PKCε levels in the NAc and CeA. Finally, neuropharmacologic inhibition of PKCε translocation within both regions reduced binge alcohol consumption in a manner requiring intact group 1 metabotropic glutamate receptors, Homer2, phospholipase C, and/or phosphotidylinositide-3 kinase function. Taken together, these data indicate that PKCε signaling in both the NAc and CeA is a major contributor to binge alcohol drinking and to the genetic propensity to consume excessive amounts of alcohol. Copyright © 2016 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

  17. Shape memory polymer foams for endovascular therapies

    Science.gov (United States)

    Wilson, Thomas S [Castro Valley, CA; Maitland, Duncan J [Pleasant Hill, CA

    2012-03-13

    A system for occluding a physical anomaly. One embodiment comprises a shape memory material body wherein the shape memory material body fits within the physical anomaly occluding the physical anomaly. The shape memory material body has a primary shape for occluding the physical anomaly and a secondary shape for being positioned in the physical anomaly.

  18. Separable Representation of Nucleon-Nucleus Optical Potentials as Input to (d; p) Reaction Calculations

    Science.gov (United States)

    Hlophe, Linda D.

    The three-body description of deuteron-induced nuclear reactions requires the nucleon-nucleon (NN) and effective nucleon-nucleus interactions as input. The latter are given by Optical Model Potentials (OMPs), which are complex as well as energy-dependent. While a lot of effort has been dedicated to creating separable NN potentials, the same is not true for the nucleon-nucleus OMPs. In this work, separable representations of nucleon-nucleus OMPs are presented. To construct separable representations of neutron-nucleus OMPs, a scheme due to Ernst, Shakin, and Thaler (EST) is adopted as a starting point. It is shown that, by including both incoming and outgoing scattering states in the EST scheme, separable expansions for complex neutron-nucleus potentials that partially obey reciprocity are obtained. For the application to neutron-nucleus potentials that are complex as well as energy-dependent, a further generalization is carried out leading to an energy-dependent separable expansion that exactly fulfills reciprocity. By working exclusively with half-shell transition matrices in momentum space, the implementation of these separable representation schemes is straightforward. The proton-nucleus interaction consists of a short-ranged nuclear piece as well as the long-ranged point-Coulomb potential. After separating the point-Coulomb piece via the Gell-Mann-Goldberger relation, one is left with the short-ranged potential in the Coulomb basis. An extension of the separable representation schemes for neutron-nucleus OMPs to proton-nucleus systems thus requires scattering solutions in the Coulomb basis. This complicates a momentum space implementation of the aforementioned separable expansions. However, by employing the techniques first suggested by Elster, Liu, and Thaler, the separable representation schemes generalized for proton-nucleus OMPs are implemented in a similar manner to neutron-nucleus OMPs. Taking into account the internal structure of the nucleus leads to

  19. Neurotransmitter mechanisms in the nucleus accumbens septi and related regions in the rat brain

    Energy Technology Data Exchange (ETDEWEB)

    Walaas, I.

    1981-06-30

    The investigation compares the localization of different transmitter candidates, particularly the amino acide ..gamma..-aminobutyrate (GABA) and glutamate (GLU), in limbic and basal ganglia regions in the rat brain. In particular, the characteristics of nucleus accumbens septi have been studied in some detail. GABA neurons have been found in nucleus accumbens, and GABA projections from this nucleus have been identified in restricted basal forebrain and mesencephalic regions. GLU projections from the neo- or allocortex have been found to terminate in nucleus accumbens and other forebrain and hypothalamic nuclei. Neurotransmitters in local neurons have been identified in the hippocampus, nucleus accumbens, septum and caudatoputamen by means of local kainic acid injections, while neurons in the mediobasal hypothalamus have been studied after systemic treatment of newborn animals with monosodium glutamate. The results are discussed as a basis for a better understanding of limbic-basal ganglia interactions.

  20. Projection of secondary vestibular neurons to the abducens nucleus in the carpet shark Cephaloscyllium isabella.

    Science.gov (United States)

    Montgomery, J C; Cotton, P

    1985-01-01

    The abducens nucleus in carpet sharks is not a discrete delimited nucleus, as the dendrites of the motoneurons extend into the reticular formation and the medial longitudinal fasciculus. Injections of horseradish peroxidase (HRP) designed to trace the inputs to these neurons are therefore difficult to confine to this system alone. Despite this problem a consistent finding from injection of HRP in the area of the abducens nucleus is the retrograde labelling of a column of cells in the contralateral octaval nuclei. The column of cells is predominantly in the ventral portion of the descending octaval nucleus, but does straddle the entrance of nerve VIII, extending into the caudal part of the ascending octaval nucleus. Labelled cells correspond in location and morphology to those cells receiving input from horizontal canal afferent fibers, confirming the trineuronal nature of the horizontal vestibulo-ocular reflex arc in elasmobranch fishes.

  1. Preservation of the nucleus X-pelvic floor motosystem in amyotrophic lateral sclerosis

    DEFF Research Database (Denmark)

    Schrøder, H D; Reske-Nielsen, E

    1984-01-01

    were observed in Onuf's nucleus X, not even in 8 cases in which other caudal motoneuron nuclei presented a severe loss of neurons. The striated sphincters proper demonstrated no signs of neurogenic atrophy in contrast to muscles in the limbs. The bulbo- and ischiocavernosus muscles, also supposedly......Fourteen cases of amyotrophic lateral sclerosis (ALS) were investigated neuropathologically, emphazising the sacral spinal cord which contains Onuf's nucleus X. The nucleus innervates the pelvic sphincters. In two cases, small striated pelvic muscles were studied. No changes characteristic of ALS...... innervated by Onuf's nucleus, were without pathological changes. Moreover, the latter two muscles were found to have a composition very similar to that of the sphincters. This indicates that a characteristic morphology of the nucleus X-innervated muscles exists. A review of the clinical records of all...

  2. Influence of recipient cytoplasm cell stage on transcription in bovine nucleus transfer embryos

    DEFF Research Database (Denmark)

    Smith, Steven D.; Soloy, Eva; Kanka, Jiri

    1996-01-01

    Nucleus transfer for the production of multiple embryos derived from a donor embryo relies upon the reprogramming of the donor nucleus so that it behaves similar to a zygotic nucleus. One indication of nucleus reprogramming is the RNA synthetic activity. In normal bovine embryogenesis, the embryo...... relies upon maternally derived RNA transcripts up to the 8-cell stage, at which time it begins to transcribe its own RNA. In this experiment, RNA synthesis was detected in nucleus transfer embryos (NTE) and control embryos by pulsing with 3H-uridine, fixation, and autoradiography on semithin sections....... NTE were produced using either a MII phase (nonactivated) cytoplasts at 32 hr of maturation or S-phase (activated) cytoplasts activated with calcium ionophore A23187 and cycloheximide treatment approximately 8 hr prior to fusion with a blastomere from an in-vitro-produced morula stage embryo at 32 hr...

  3. Systematic study of multiparticle production in nucleus–nucleus ...

    Indian Academy of Sciences (India)

    An experimental analysis of 855 events induced by 14.6 A GeV 28Si in nuclear emul- sion is presented. ... In order to accumulate knowledge about the intermittent behaviour of shower particles, the scaled factorial ..... problem associated with the shape dependence of the single-particle density distribution can be taken care ...

  4. Emotional collectives: How groups shape emotions and emotions shape groups.

    Science.gov (United States)

    van Kleef, Gerben A; Fischer, Agneta H

    2016-01-01

    Group settings are epicentres of emotional activity. Yet, the role of emotions in groups is poorly understood. How do group-level phenomena shape group members' emotional experience and expression? How are emotional expressions recognised, interpreted and shared in group settings? And how do such expressions influence the emotions, cognitions and behaviours of fellow group members and outside observers? To answer these and other questions, we draw on relevant theoretical perspectives (e.g., intergroup emotions theory, social appraisal theory and emotions as social information theory) and recent empirical findings regarding the role of emotions in groups. We organise our review according to two overarching themes: how groups shape emotions and how emotions shape groups. We show how novel empirical approaches break important new ground in uncovering the role of emotions in groups. Research on emotional collectives is thriving and constitutes a key to understanding the social nature of emotions.

  5. Shape Control of Solar Collectors Using Shape Memory Alloy Actuators

    Science.gov (United States)

    Lobitz, D. W.; Grossman, J. W.; Allen, J. J.; Rice, T. M.; Liang, C.; Davidson, F. M.

    1996-01-01

    Solar collectors that are focused on a central receiver are designed with a mechanism for defocusing the collector or disabling it by turning it out of the path of the sun's rays. This is required to avoid damaging the receiver during periods of inoperability. In either of these two cases a fail-safe operation is very desirable where during power outages the collector passively goes to its defocused or deactivated state. This paper is principally concerned with focusing and defocusing the collector in a fail-safe manner using shape memory alloy actuators. Shape memory alloys are well suited to this application in that once calibrated the actuators can be operated in an on/off mode using a minimal amount of electric power. Also, in contrast to other smart materials that were investigated for this application, shape memory alloys are capable of providing enough stroke at the appropriate force levels to focus the collector. Design and analysis details presented, along with comparisons to test data taken from an actual prototype, demonstrate that the collector can be repeatedly focused and defocused within accuracies required by typical solar energy systems. In this paper the design, analysis and testing of a solar collector which is deformed into its desired shape by shape memory alloy actuators is presented. Computations indicate collector shapes much closer to spherical and with smaller focal lengths can be achieved by moving the actuators inward to a radius of approximately 6 inches. This would require actuators with considerably more stroke and some alternate SMA actuators are currently under consideration. Whatever SMA actuator is finally chosen for this application, repeatability and fatigue tests will be required to investigate the long term performance of the actuator.

  6. Finite Element Study of a Lumbar Intervertebral Disc Nucleus Replacement Device.

    Science.gov (United States)

    Coogan, Jessica S; Francis, W Loren; Eliason, Travis D; Bredbenner, Todd L; Stemper, Brian D; Yoganandan, Narayan; Pintar, Frank A; Nicolella, Daniel P

    2016-01-01

    Nucleus replacement technologies are a minimally invasive alternative to spinal fusion and total disc replacement that have the potential to reduce pain and restore motion for patients with degenerative disc disease. Finite element modeling can be used to determine the biomechanics associated with nucleus replacement technologies. The current study focuses on a new nucleus replacement device designed as a conforming silicone implant with an internal void. A validated finite element model of the human lumbar L3-L4 motion segment was developed and used to investigate the influence of the nucleus replacement device on spine biomechanics. In addition, the effect of device design changes on biomechanics was determined. A 3D, L3-L4 finite element model was constructed from medical imaging data. Models were created with the normal intact nucleus, the nucleus replacement device, and a solid silicone implant. Probabilistic analysis was performed on the normal model to provide quantitative validation metrics. Sensitivity analysis was performed on the silicone Shore A durometer of the device. Models were loaded under axial compression followed by flexion/extension, lateral bending, or axial rotation. Compressive displacement, endplate stresses, reaction moment, and annulus stresses were determined and compared between the different models. The novel nucleus replacement device resulted in similar compressive displacement, endplate stress, and annulus stress and slightly higher reaction moment compared with the normal nucleus. The solid implant resulted in decreased displacement, increased endplate stress, decreased annulus stress, and decreased reaction moment compared with the novel device. With increasing silicone durometer, compressive displacement decreased, endplate stress increased, reaction moment increased, and annulus stress decreased. Finite element analysis was used to show that the novel nucleus replacement device results in similar biomechanics compared with the

  7. Finite element study of a lumbar intervertebral disc nucleus replacement device

    Directory of Open Access Journals (Sweden)

    Jessica S Coogan

    2016-12-01

    Full Text Available Nucleus replacement technologies are a minimally invasive alternative to spinal fusion and total disc replacement that have the potential to reduce pain and restore motion for patients with degenerative disc disease. Finite element modeling can be used to determine the biomechanics associated with nucleus replacement technologies. The current study focuses on a new nucleus replacement device designed as a conforming silicone implant with an internal void. A validated finite element model of the human lumbar L3-L4 motion segment was developed and used to investigate the influence of the nucleus replacement device on spine biomechanics. In addition, the effect of device design changes on biomechanics was determined. A 3D, L3-L4 finite element model was constructed from medical imaging data. Models were created with the normal intact nucleus, the nucleus replacement device, and a solid silicone implant. Probabilistic analysis was performed on the normal model to provide quantitative validation metrics. Sensitivity analysis was performed on the silicone Shore A durometer of the device. Models were loaded under axial compression followed by flexion/extension, lateral bending, or axial rotation. Compressive displacement, endplate stresses, reaction moment, and annulus stresses were determined and compared between the different models. The novel nucleus replacement device resulted in similar compressive displacement, endplate stress, and annulus stress and slightly higher reaction moment compared with the normal nucleus. The solid implant resulted in decreased displacement, increased endplate stress, decreased annulus stress, and decreased reaction moment compared with the novel device. With increasing silicone durometer, compressive displacement decreased, endplate stress increased, reaction moment increased, and annulus stress decreased. Finite element analysis was used to show that the novel nucleus replacement device results in similar biomechanics

  8. Triaxiality and isospin-forbidden E1 decays in the N=Z nucleus sup 64 Ge

    Energy Technology Data Exchange (ETDEWEB)

    Ennis, P.J.; Lister, C.J. (A.W. Wright Nuclear Structure Lab., Yale Univ., New Haven, CT (United States)); Gelletly, W.; Price, H.G. (SERC Daresbury Lab., Warrington (United Kingdom)); Varly, B.J. (Schuster Lab., Univ. Manchester (United Kingdom)); Butler, P.A.; Hoare, T. (Oliver Lodge Lab., Univ. Liverpool (United Kingdom)); Cwiok, S. (Inst. of Physics, Warsaw Inst. of Tech. (Poland)); Nazarewicz, W. (Joint Inst. of Heavy-Ion Research, Holifield Heavy-Ion Research Facility, Oak Ridge, TN (United States))

    1991-12-16

    The neutron-deficient isotope {sup 64}{sub 32}Ge{sub 32} was produced in the reaction {sup 12}C({sup 54}Fe, 2n{gamma}){sup 64}Ge at a beam energy of 165 MeV. The production cross section for {sup 64}Ge was measured to be 640{+-}70 {mu}b, which represents only {proportional to}0.1% of the total fusion cross section. The Daresbury recoil separator was operated in conjunction with a large {gamma}-array to study recoil-{gamma}{gamma} correlations and measure recoil-{gamma} angular distributions. A level scheme for {sup 64}Ge was constructed containing 19 levels. The nucleus appears to have a structure consistent with a {gamma}-soft shape. Shape changes induced by aligned g{sub 9/2} nucleons are discussed. An overview of octupole correlations in the A{approx equal}60-80 mass region is given. Evidence for forbidden E1 transitions was found which is indicative of considerable isospin mixing. (orig.).

  9. Statistical models of shape optimisation and evaluation

    CERN Document Server

    Davies, Rhodri; Taylor, Chris

    2014-01-01

    Deformable shape models have wide application in computer vision and biomedical image analysis. This book addresses a key issue in shape modelling: establishment of a meaningful correspondence between a set of shapes. Full implementation details are provided.

  10. Clinical study of intelligent phacoemulsification for hard nucleus cataract extraction

    Directory of Open Access Journals (Sweden)

    Cun Sun

    2016-07-01

    Full Text Available AIM: To compare the efficiency and safety of torsional phacoemulsification with or without intelligent phacoemulsification(IPsoftware in hard nucleus cataract extraction. METHODS: Ninety two eyes with Ⅳ-Ⅴgrades cataracts were enrolled in this randomized prospective study. Operated eyes were divided into two groups-those operated without IP software(non-IP group, n=43and those operated using IP software(IP group, n=49. The two groups were compared in terms of ultrasound time(USTand cumulative dissipated energy(CDE. Post-operative outcome measures included the corneal edema and best-corrected visual acuity(BCVAat 1,7d and 3mo postoperatively, corneal endothelial cell density and percentage of hexagonal cell at 7d and 3mo postoperatively. RESULTS: UST was measured as 52.51±9.64s in non-IP Group and 48.79±7.13s in IP Group(P=0.030. CDE was 15.78±3.73% in non-IP Group and 14.29±2.77% in IP Group(P=0.026. At the first postoperative day, the rate of BCVA>0.1 in non-IP Group was 56%, and the rate in IP Group was 79%(P=0.066. Corneal edema in non-IP Group was 2.98±0.77 scores, and in IP Group it was 2.61±0.64 scores(P=0.021. At the postoperative 7 and 30d, the BCVA and corneal edema were no differences between two groups. At the postoperative 7d, corneal endothelial cell density in non-IP Group were 2497.95±211.48/mm2, less than 2586.26±154.71/mm2 in IP Group(P=0.029; percentage of hexagonal cell in IP group was 48.33±8.69%,higher than 44.19±9.48% of non-IP group(P=0.030. CONCLUSION: In hard nucleus cataract extraction, the IP software can combine the advantages of the two kinds of ultrasonic modes, which is more effective with lower ultrasound energy and less injury for the corneal endothclium, and is helpful for the recovery of vision at early stage after surgeries.

  11. Geniculohypothalamic GABAergic projections gate suprachiasmatic nucleus responses to retinal input.

    Science.gov (United States)

    Hanna, Lydia; Walmsley, Lauren; Pienaar, Abigail; Howarth, Michael; Brown, Timothy M

    2017-06-01

    Visual input to the suprachiasmatic nucleus circadian clock is critical for animals to adapt their physiology and behaviour in line with the solar day. In addition to direct retinal projections, the clock receives input from the visual thalamus, although the role of this geniculohypothalamic pathway in circadian photoreception is poorly understood. In the present study, we develop a novel brain slice preparation that preserves the geniculohypothalamic pathway to show that GABAergic thalamic neurons inhibit retinally-driven activity in the central clock in a circadian time-dependent manner. We also show that in vivo manipulation of thalamic signalling adjusts specific features of the hypothalamic light response, indicating that the geniculohypothalamic pathway is primarily activated by crossed retinal inputs. Our data provide a mechanism by which geniculohypothalamic signals can adjust the magnitude of circadian and more acute hypothalamic light responses according to time-of-day and establish an important new model for future investigations of the circadian visual system. Sensory input to the master mammalian circadian clock, the suprachiasmatic nucleus (SCN), is vital in allowing animals to optimize physiology and behaviour alongside daily changes in the environment. Retinal inputs encoding changes in external illumination provide the principle source of such information. The SCN also receives input from other retinorecipient brain regions, primarily via the geniculohypothalamic tract (GHT), although the contribution of these indirect projections to circadian photoreception is currently poorly understood. To address this deficit, in the present study, we established an in vitro mouse brain slice preparation that retains connectivity across the extended circadian system. Using multi-electrode recordings, we first confirm that this preparation retains intact optic projections to the SCN, thalamus and pretectum and a functional GHT. We next show that optogenetic

  12. A multi-compartment model for interneurons in the dorsal lateral geniculate nucleus.

    Directory of Open Access Journals (Sweden)

    Geir Halnes

    2011-09-01

    Full Text Available GABAergic interneurons (INs in the dorsal lateral geniculate nucleus (dLGN shape the information flow from retina to cortex, presumably by controlling the number of visually evoked spikes in geniculate thalamocortical (TC neurons, and refining their receptive field. The INs exhibit a rich variety of firing patterns: Depolarizing current injections to the soma may induce tonic firing, periodic bursting or an initial burst followed by tonic spiking, sometimes with prominent spike-time adaptation. When released from hyperpolarization, some INs elicit rebound bursts, while others return more passively to the resting potential. A full mechanistic understanding that explains the function of the dLGN on the basis of neuronal morphology, physiology and circuitry is currently lacking. One way to approach such an understanding is by developing a detailed mathematical model of the involved cells and their interactions. Limitations of the previous models for the INs of the dLGN region prevent an accurate representation of the conceptual framework needed to understand the computational properties of this region. We here present a detailed compartmental model of INs using, for the first time, a morphological reconstruction and a set of active dendritic conductances constrained by experimental somatic recordings from INs under several different current-clamp conditions. The model makes a number of experimentally testable predictions about the role of specific mechanisms for the firing properties observed in these neurons. In addition to accounting for the significant features of all experimental traces, it quantitatively reproduces the experimental recordings of the action-potential- firing frequency as a function of injected current. We show how and why relative differences in conductance values, rather than differences in ion channel composition, could account for the distinct differences between the responses observed in two different neurons, suggesting

  13. The influence of shape-holding conditions on shape recovery of polyurethane-shape memory polymer foams

    Science.gov (United States)

    Tobushi, H.; Matsui, R.; Hayashi, S.; Shimada, D.

    2004-08-01

    The thermomechanical properties of polyurethane-shape memory polymer (SMP) foams and the influence of shape-holding conditions on shape recovery were investigated experimentally. The results obtained can be summarized as follows. (1) By cooling the foam down to below the glass transition temperature Tg after compressive deformation above Tg, stress decreases and the deformed shape is fixed. By heating the shape-fixed foam up to above Tg under no load, the original shape is recovered. (2) The shape deformed above Tg is maintained for six months under no load at Tg- 60 K without depending on the maximum strain, and the original shape is recovered by heating thereafter. (3) If the deformed shape is held at high temperature, the original shape is not recovered. (4) The ratio of shape irrecovery increases in proportion to the holding strain, holding temperature and holding time.

  14. Lunar Regolith Particle Shape Analysis

    Science.gov (United States)

    Kiekhaefer, Rebecca; Hardy, Sandra; Rickman, Douglas; Edmunson, Jennifer

    2013-01-01

    Future engineering of structures and equipment on the lunar surface requires significant understanding of particle characteristics of the lunar regolith. Nearly all sediment characteristics are influenced by particle shape; therefore a method of quantifying particle shape is useful both in lunar and terrestrial applications. We have created a method to quantify particle shape, specifically for lunar regolith, using image processing. Photomicrographs of thin sections of lunar core material were obtained under reflected light. Three photomicrographs were analyzed using ImageJ and MATLAB. From the image analysis measurements for area, perimeter, Feret diameter, orthogonal Feret diameter, Heywood factor, aspect ratio, sieve diameter, and sieve number were recorded. Probability distribution functions were created from the measurements of Heywood factor and aspect ratio.

  15. Event shape engineering with ALICE

    CERN Document Server

    Dobrin, A

    2013-01-01

    The strong fluctuations in the initial energy density of heavy-ion collisions allow an efficient selection of events corresponding to a specific initial geometry. For such "shape engineered events", the elliptic flow coefficient, $v_2$, of unidentified charged particles, pions and (anti-)protons in Pb-Pb collisions at $\\snn = 2.76$ TeV is measured by the ALICE collaboration. $v_2$ obtained with the event plane method at mid-rapidity, $|\\eta|<0.8$, is reported for different collision centralities as a function of transverse momentum, $\\pt$, out to $\\pt=20$ GeV/$c$. The measured $v_2$ for the shape engineered events is significantly larger or smaller than the average which demonstrates the ability to experimentally select events with the desired shape of the initial spatial asymmetry.

  16. Shape and Dimensions of Ripples

    DEFF Research Database (Denmark)

    Jacobsen, Niels Gjøl

    In this work, the flow and bed load transport over ripple profiles under the influence of oscillatory will be investigated. The investigation is made through a parametric study, where the bed shape and the ripple steepness are varied. For the sediment transport, the Shields parameter relative to ...... is to investigate how a perturbation on top of the ripple influences the flow. It will be seen that both the shape and the velocity of the crest are affecting the period averaged flow globally.......In this work, the flow and bed load transport over ripple profiles under the influence of oscillatory will be investigated. The investigation is made through a parametric study, where the bed shape and the ripple steepness are varied. For the sediment transport, the Shields parameter relative...

  17. Quantifying the shape of aging

    DEFF Research Database (Denmark)

    Wrycza, Tomasz F; Missov, Trifon I; Baudisch, Annette

    2015-01-01

    of aging rates, suggest the shape of aging as a novel and valuable alternative concept for comparative aging research. The concept of shape captures the direction and degree of change in the force of mortality over age, which—on a demographic level—reflects aging. We 1) provide a list of shape properties......In Biodemography, aging is typically measured and compared based on aging rates. We argue that this approach may be misleading, because it confounds the time aspect with the mere change aspect of aging. To disentangle these aspects, here we utilize a time-standardized framework and, instead...... suggested here aim to provide a general means to classify aging patterns independent of any particular mortality model and independent of any species-specific time-scale. Thereby they support systematic comparative aging research across different species or between populations of the same species under...

  18. Optimal shapes for best draining

    Science.gov (United States)

    Sherwood, J. D.

    2009-11-01

    The container shape that minimizes the volume of draining fluid remaining on the walls of the container after it has been emptied from its base is determined. The film of draining fluid is assumed to wet the walls of the container, and is sufficiently thin so that its curvature may be neglected. Surface tension is ignored. The initial value problem for the thickness of a film of Newtonian fluid is studied, and is shown to lead asymptotically to a similarity solution. From this, and from equivalent solutions for power-law fluids, the volume of the residual film is determined. The optimal container shape is not far from hemispherical, to minimize the surface area, but has a conical base to promote draining. The optimal shape for an axisymmetric mixing vessel, with a hole at the center of its base for draining, is also optimal when inverted in the manner of a washed wine glass inverted and left to drain.

  19. Tunable polymer multi-shape memory effect.

    Science.gov (United States)

    Xie, Tao

    2010-03-11

    Shape memory polymers are materials that can memorize temporary shapes and revert to their permanent shape upon exposure to an external stimulus such as heat, light, moisture or magnetic field. Such properties have enabled a variety of applications including deployable space structures, biomedical devices, adaptive optical devices, smart dry adhesives and fasteners. The ultimate potential for a shape memory polymer, however, is limited by the number of temporary shapes it can memorize in each shape memory cycle and the ability to tune the shape memory transition temperature(s) for the targeted applications. Currently known shape memory polymers are capable of memorizing one or two temporary shapes, corresponding to dual- and triple-shape memory effects (also counting the permanent shape), respectively. At the molecular level, the maximum number of temporary shapes a shape memory polymer can memorize correlates directly to the number of discrete reversible phase transitions (shape memory transitions) in the polymer. Intuitively, one might deduce that multi-shape memory effects are achievable simply by introducing additional reversible phase transitions. The task of synthesizing a polymer with more than two distinctive and strongly bonded reversible phases, however, is extremely challenging. Tuning shape memory effects, on the other hand, is often achieved through tailoring the shape memory transition temperatures, which requires alteration in the material composition. Here I show that the perfluorosulphonic acid ionomer (PFSA), which has only one broad reversible phase transition, exhibits dual-, triple-, and at least quadruple-shape memory effects, all highly tunable without any change to the material composition.

  20. Emotional collectives : How groups shape emotions and emotions shape groups

    NARCIS (Netherlands)

    van Kleef, G.A.; Fischer, A.H.

    2016-01-01

    Group settings are epicentres of emotional activity. Yet, the role of emotions in groups is poorly understood. How do group-level phenomena shape group members’ emotional experience and expression? How are emotional expressions recognised, interpreted and shared in group settings? And how do such

  1. Star-Shaped Conjugated Systems

    Directory of Open Access Journals (Sweden)

    Heiner Detert

    2010-05-01

    Full Text Available The present review deals with the preparation and the properties of star-shaped conjugated compounds. Three, four or six conjugated arms are attached to cross-conjugated cores, which consist of single atoms (B, C+, N, benzene or azine rings or polycyclic ring systems, as for example triphenylene or tristriazolotriazine. Many of these shape-persistent [n]star compounds tend to π-stacking and self-organization, and exhibit interesting properties in materials science: Linear and non-linear optics, electrical conductivity, electroluminescence, formation of liquid crystalline phases, etc.

  2. Decay Properties of the Halo Nucleus $^{11}$Li

    CERN Multimedia

    2002-01-01

    During the past years a considerable experimental effort has been devoted to the production and study of nuclei close to the neutron and proton drip-lines. The most spectacular phenomenon encountered is the occurrence of neutron halos in the loosely bound neutron rich nuclei. \\\\ \\\\ Another interesting feature, observed at ISOLDE, which most likely is connected to the halo structure, is the very strong (super-allowed) Gamow-Teller $\\beta$- transitions to highly excited states which are systematically observed for the lightest neutron rich drip-line nuclei. These transitions might be viewed as arising from the quasi-free $\\beta$ -decay of the halo neutrons. It is proposed to make a detailed study of the $\\beta$- strength function for $^{11}$Li, a nuclide having a half-life of 8.2 ms and a Q $\\beta$-value of 20.73~MeV. \\\\ \\\\ So far only a lower limit of the Gamow-Teller transition rate to highly excited states ($\\approx$~18.5~MeV) in the daughter nucleus has been obtained from measurements of $\\beta$-delayed tri...

  3. Nicotinic modulation of serotonergic activity in the dorsal raphe nucleus.

    Science.gov (United States)

    Hernandez-Lopez, Salvador; Garduño, Julieta; Mihailescu, Stefan

    2013-01-01

    Cholinergic signaling mediated by nicotinic receptors has been associated to a large number of physiological and behavioral processes such as learning, memory, attention, food-intake and mood disorders. Although it is well established that many nicotinic actions are mediated through an increase in serotonin (5-HT) release, the physiological mechanisms by which nicotine produces these effects are still unclear. The dorsal raphe nucleus (DRN) contains the major amount of 5-HT neurons projecting to different parts of the brain. DRN also contains nicotinic acetylcholine receptors (nAChRs) located at somatic and presynaptic elements. Nicotine produces both inhibitory and excitatory effects on different subpopulations of 5-HT DRN neurons. In this review, we describe the presynaptic and postsynaptic mechanisms by which nicotine increases the excitability of DRN neurons as well as the subtypes of nAChRs involved. We also describe the inhibitory effects of nicotine and the role of 5-HT1A receptors in this effect. These nicotinic actions modulate the activity of different neuronal subpopulations in the DRN, changing the 5-HT tone in the brain areas where these groups of neurons project. Some of the physiological implications of nicotine-induced 5-HT release are discussed.

  4. Developmental switch of leptin signaling in arcuate nucleus neurons.

    Science.gov (United States)

    Baquero, Arian F; de Solis, Alain J; Lindsley, Sarah R; Kirigiti, Melissa A; Smith, M Susan; Cowley, Michael A; Zeltser, Lori M; Grove, Kevin L

    2014-07-23

    Leptin is well known for its role in the regulation of energy homeostasis in adults, a mechanism that at least partially results from the inhibition of the activity of NPY/AgRP/GABA neurons (NAG) in the arcuate nucleus of the hypothalamus (ARH). During early postnatal development in the rodent, leptin promotes axonal outgrowth from ARH neurons, and preautonomic NAG neurons are particularly responsive to leptin's trophic effects. To begin to understand how leptin could simultaneously promote axonal outgrowth from and inhibit the activity of NAG neurons, we characterized the electrochemical effects of leptin on NAG neurons in mice during early development. Here, we show that NAG neurons do indeed express a functional leptin receptor throughout the early postnatal period in the mouse; however, at postnatal days 13-15, leptin causes membrane depolarization in NAG neurons, rather than the expected hyperpolarization. Leptin action on NAG neurons transitions from stimulatory to inhibitory in the periweaning period, in parallel with the acquisition of functional ATP-sensitive potassium channels. These findings are consistent with the idea that leptin provides an orexigenic drive through the NAG system to help rapidly growing pups meet their energy requirements. Copyright © 2014 the authors 0270-6474/14/349982-13$15.00/0.

  5. Nucleus accumbens core and pathogenesis of compulsive checking

    Science.gov (United States)

    Ballester González, Javier; Dvorkin-Gheva, Anna; Silva, Charmaine; Foster, Jane A.

    2015-01-01

    To investigate the role of the nucleus accumbens core (NAc) in the development of quinpirole-induced compulsive checking, rats received an excitotoxic lesion of NAc or sham lesion and were injected with quinpirole (0.5 mg/kg) or saline; development of checking behavior was monitored for 10 biweekly tests. The results showed that even after the NAc lesion, quinpirole still induced compulsive checking, suggesting that the pathogenic effects produced by quinpirole lie outside the NAc. Although the NAc lesion did not prevent the induction of compulsive checking, it altered how quickly it develops, suggesting that the NAc normally contributes toward the induction of compulsive checking. Saline-treated rats with an NAc lesion were hyperactive, but did not develop compulsive checking, indicating that hyperactivity by itself is not sufficient for the pathogenesis of compulsive checking. It is proposed that compulsive checking is the exaggerated output of a security motivation system and that the NAc serves as a neural hub for coordinating the orderly activity of neural modules of this motivational system. Evidence is considered suggesting that the neurobiological condition for the pathogenesis of compulsive checking is two-fold: activation of dopamine D2/D3 receptors without concurrent stimulation of D1-like receptors and long-term plastic changes related to quinpirole-induced sensitization. PMID:25426580

  6. Comparative study of alpha + nucleus elastic scattering using different models

    Science.gov (United States)

    Al-Ghamdi, A. H.; Ibraheem, Awad A.; El-Azab Farid, M.

    2015-01-01

    The alpha (α) elastic scattering from different targets potential over the energy range 10-240 MeV has been analyzed in the framework of the single-folding (SF) optical model. Four targets are considered, namely, 24Mg, 28Si, 32S and 40Ca. The SF calculations for the real central part of the nuclear optical potential are performed by folding an effective α-α interaction with the α-cluster distribution density in the target nucleus. The imaginary part of the optical potential is expressed in the phenomenological Woods-Saxon (WS) form. The calculated angular distributions of the elastic scattering differential cross-section using the derived semimicroscopic potentials successfully reproduce 36 sets of data all over the measured angular ranges. The obtained results confirm the validity of the α-cluster structure of the considered nuclei. For the sake of comparison, the same sets of data are reanalyzed using microscopic double-folded optical potentials based upon the density-dependent Jeukenne-Lejeune-Mahaux (JLM) effective nucleon-nucleon interaction.

  7. The thalamic reticular nucleus: structure, function and concept.

    Science.gov (United States)

    Pinault, Didier

    2004-08-01

    On the basis of theoretical, anatomical, psychological and physiological considerations, Francis Crick (1984) proposed that, during selective attention, the thalamic reticular nucleus (TRN) controls the internal attentional searchlight that simultaneously highlights all the neural circuits called on by the object of attention. In other words, he submitted that during either perception, or the preparation and execution of any cognitive and/or motor task, the TRN sets all the corresponding thalamocortical (TC) circuits in motion. Over the last two decades, behavioural, electrophysiological, anatomical and neurochemical findings have been accumulating, supporting the complex nature of the TRN and raising questions about the validity of this speculative hypothesis. Indeed, our knowledge of the actual functioning of the TRN is still sprinkled with unresolved questions. Therefore, the time has come to join forces and discuss some recent cellular and network findings concerning this diencephalic GABAergic structure, which plays important roles during various states of consciousness. On the whole, the present critical survey emphasizes the TRN's complexity, and provides arguments combining anatomy, physiology and cognitive psychology.

  8. Examining exotic structure of proton-rich nucleus $^{23}$Al

    CERN Document Server

    Fang, D Q; Ma, C W; Wang, K; Yan, T Z; Ma, Y G; Cai, X Z; Shen, W Q; Ren, Z Z; Sun, Z Y; Chen, J G; Tian, W D; Zhong, C; Hosoi, M; Izumikawa, T; Kanungo, R; Nakajima, S; Ohnishi, T; Ohtsubo, T; Ozawa, A; Suda, T; Sugawara, K; Suzuki, T; Takisawa, A; Tanaka, K; Yamaguchi, T; Tanihata, I

    2007-01-01

    The longitudinal momentum distribution (P_{//}) of fragments after one-proton removal from ^{23} Al and reaction cross sections (\\sigma_R) for ^{23,24} Al on carbon target at 74A MeV have been measured. The ^{23,24} Al ions were produced through projectile fragmentation of 135 A MeV ^{28} Si primary beam using RIPS fragment separator at RIKEN. P_{//} is measured by a direct time-of-flight (TOF) technique, while \\sigma_R is determined using a transmission method. An enhancement in \\sigma_R is observed for ^{23} Al compared with ^{24} Al. The P_{//} for ^{22} Mg fragments from ^{23} Al breakup has been obtained for the first time. FWHM of the distributions has been determined to be 232 \\pm 28 MeV/c. The experimental data are discussed by using Few-Body Glauber model. Analysis of P_{//} demonstrates a dominant d-wave configuration for the valence proton in ground state of ^{23} Al, indicating that ^{23} Al is not a proton halo nucleus.

  9. Caudate Nucleus in Retrieval of Trace Eyeblink Conditioning after Consolidation

    Science.gov (United States)

    Flores, Luke C.; Disterhoft, John F.

    2013-01-01

    Trace eyeblink conditioning (EBC) is an associative learning task in which a stimulus-free trace period separates the presentation of a behaviorally neutral conditioned stimulus (CS, whisker stimulation) from a behaviorally salient unconditioned stimulus (US, airpuff to the eye). Repeated pairings of the CS with the US results in the emergence of the conditioned response (CR, eyeblink following CS presentation and preceding US presentation). The goal of these experiments was to determine whether the caudate nucleus (CN) plays a role in retrieval of previously acquired trace EBC after memory consolidation. Lesions of the CN were made one month after initial trace EBC. CN lesioned rabbits performed fewer adaptive CRs and more short-latency non-adaptive responses than sham lesioned controls. They were not able to improve their CR performance after consolidation as were controls. Single unit recordings taken from separate cohorts of rabbits demonstrated that neurons in the CN were still responsive to the CS and US one month after initial trace EBC, particularly in the medial and ventral CN on trials when a CR occurred. The proportion of rate increasing neurons was higher in trace conditioned than in pseudo conditioned rabbits. Neurons in regions destroyed in the behavioral experiment demonstrated prolonged firing during the trace period, which might underlie the results from the behavioral experiment. These data demonstrate that the CN plays an important role in retrieval of a previously learned associative task after memory consolidation has occurred. PMID:23407942

  10. Thalamocortical projections of the anteroventral thalamic nucleus in the rabbit.

    Science.gov (United States)

    Shibata, Hideshi; Yoshiko, Honda

    2015-04-01

    The anterior thalamic nuclei are one of the regions that play critical roles in behavioral learning and memory functions. A part of the anterior thalamic nuclei, the anteroventral nucleus (AV) is well developed and differentiated into the parvocellular (AVp) and magnocellular (AVm) division in the rabbit. The AV is crucial for learning discriminative avoidance conditioning. Although communication between the AV and cortex is considered important in learning, little is known about the neural connections of the AV in the rabbit. Thus, this study used anterograde tracer biotinylated dextran amine and the retrograde tracer cholera toxin B subunit to examine the organization of the thalamocortical projections of the AV. Our data show that each division of the AV provides a unique set of projections to restricted regions and layers of the retrosplenial cortex and presubiculum. In addition, the AVp projects to layers I and IV of retrosplenial areas 29 and 30 and to layers I and VI of the presubiculum. The dorsolateral AVm projects to layers I and IV of area 29 and to layers I, III, and V of the presubiculum. However, the ventromedial AVm only projects to layer I of area 29. These projections are generally organized such that the rostral-to-caudal axis of the AV corresponds to the caudal-to-rostral axis of the retrosplenial cortex and to the temporal-to-septal axis of the presubiculum. These findings suggest distinct functional roles played by each division of the AV in the learning and memory functions. © 2014 Wiley Periodicals, Inc.

  11. Subthalamic nucleus stimulation affects incentive salience attribution in Parkinson's disease.

    Science.gov (United States)

    Serranová, Tereza; Jech, Robert; Dušek, Petr; Sieger, Tomáš; Růžička, Filip; Urgošík, Dušan; Růžička, Evžen

    2011-10-01

    Deep brain stimulation (DBS) of the subthalamic nucleus (STN) can induce nonmotor side effects such as behavioral and mood disturbances or body weight gain in Parkinson's disease (PD) patients. We hypothesized that some of these problems could be related to an altered attribution of incentive salience (ie, emotional relevance) to rewarding and aversive stimuli. Twenty PD patients (all men; mean age ± SD, 58.3 ± 6 years) in bilateral STN DBS switched ON and OFF conditions and 18 matched controls rated pictures selected from the International Affective Picture System according to emotional valence (unpleasantness/pleasantness) and arousal on 2 independent visual scales ranging from 1 to 9. Eighty-four pictures depicting primary rewarding (erotica and food) and aversive fearful (victims and threat) and neutral stimuli were selected for this study. In the STN DBS ON condition, the PD patients attributed lower valence scores to the aversive pictures compared with the OFF condition (P weight gain correlated with arousal ratings from the food pictures in the STN DBS ON condition (P weight gain. Copyright © 2011 Movement Disorder Society.

  12. Targeting of nucleus-encoded proteins to chloroplasts in plants.

    Science.gov (United States)

    Jarvis, Paul

    2008-07-01

    Most chloroplast proteins are encoded in the nucleus and synthesized on free, cytosolic ribosomes in precursor form. Each precursor has an amino-terminal extension called a transit peptide, which directs the protein through a post-translational targeting pathway and is removed upon arrival inside the organelle. This 'protein import' process is mediated by the coordinate action of two multiprotein complexes, one in each of the envelope membranes: the TOC and TIC (Translocon at the Outer/ Inner envelope membrane of Chloroplasts) machines. Many components of these complexes have been identified biochemically in pea; these include transit peptide receptors, channel proteins, and molecular chaperones. Intriguingly, the Arabidopsis genome encodes multiple, homologous genes for receptor components of the TOC complex. Careful analysis indicated that the different receptor isoforms operate in different import pathways with distinct precursor recognition specificities. These 'substrate-specific' import pathways might play a role in the differentiation of different plastid types, and/or act to prevent deleterious competition effects between abundant and nonabundant precursors. Until recently, all proteins destined for internal chloroplast compartments were thought to possess a cleavable transit peptide, and to engage the TOC/TIC machinery. New studies using proteomics and other approaches have revealed that this is far from true. Remarkably, a significant number of chloroplast proteins are transported via a pathway that involves the endoplasmic reticulum and Golgi apparatus. Other recent reports have elucidated an intriguing array of protein targeting routes leading to the envelope membranes themselves.

  13. On Parallel Streams through the Mouse Dorsal Lateral Geniculate Nucleus

    Directory of Open Access Journals (Sweden)

    Daniel eDenman

    2016-03-01

    Full Text Available The mouse visual system is an emerging model for the study of cortical and thalamic circuit function. To maximize the usefulness of this model system, it is important to analyze the similarities and differences between the organization of all levels of the murid visual system with other, better studied systems (e.g., non-human primates and the domestic cat. While the understanding of mouse retina and cortex has expanded rapidly, less is known about mouse dorsal lateral geniculate nucleus (dLGN. Here, we study whether parallel processing streams exist in mouse dLGN. We use a battery of stimuli that have been previously shown to successfully distinguish parallel streams in other species: electrical stimulation of the optic chiasm, contrast-reversing stationary gratings at varying spatial phase, drifting sinusoidal gratings, dense noise for receptive field reconstruction, and frozen contrast-modulating noise. As in the optic nerves of domestic cats and non-human primates, we find evidence for multiple conduction velocity groups after optic chiasm stimulation. As in so-called ‘visual mammals’, we find a subpopulation of mouse dLGN cells showing non-linear spatial summation. However, differences in stimulus selectivity and sensitivity do not provide sufficient basis for identification of clearly distinct classes of relay cells. Nevertheless, consistent with presumptively homologous status of dLGNs of all mammals, there are substantial similarities between response properties of mouse dLGN neurons and those of cats and primates.

  14. Multiparametric characterization of neuronal subpopulations in the ventrolateral preoptic nucleus.

    Science.gov (United States)

    Dubourget, Romain; Sangare, Aude; Geoffroy, Hélène; Gallopin, Thierry; Rancillac, Armelle

    2017-04-01

    The characterization of neuronal properties is a necessary first step toward understanding how the ventrolateral preoptic nucleus (VLPO) neuronal network regulates slow-wave sleep (SWS). Indeed, the electrophysiological heterogeneity of VLPO neurons suggests the existence of subtypes that could differently contribute in SWS induction and maintenance. The aim of the present study was to define cell classes in the VLPO using an unsupervised clustering classification method. Electrophysiological features extracted from 289 neurons recorded in whole-cell patch-clamp allowed the identification of three main classes of VLPO neurons subdivided into five distinct subpopulations (cluster 1, 2a, 2b, 3a and 3b). The high occurrence of a low-threshold calcium spike (LTS) was one of the most distinctive features of cluster 1 and 3. Since sleep-promoting neurons are generally identified by their ability to generate an LTS and by their inhibitory response to noradrenaline (NA), 189 neurons from our dataset were also tested for this neurotransmitter. Neurons from cluster 3 were the most frequently inhibited by NA. Biocytin labeling and Neurolucida reconstructions of 112 neurons furthermore revealed a small dendritic arbor of cluster 3b neurons compared, in particular, to cluster 2b neurons. Altogether, we performed an exhaustive characterization of VLPO neuronal subtypes that is a crucial step toward a better understanding of the neuronal network within the VLPO and thereby sleep physiology.

  15. Sex hormone receptors are present in the human suprachiasmatic nucleus.

    Science.gov (United States)

    Kruijver, Frank P M; Swaab, Dick F

    2002-05-01

    The suprachiasmatic nucleus (SCN) is the clock of the brain that orchestrates circadian and circannual biological rhythms, such as the rhythms of hormones, body temperature, sleep and mood. These rhythms are frequently disturbed in menopause and even more so in dementia and can be restored in postmenopausal women by sex hormone replacement therapy (SHRT). Although it seems clear, both from clinical and experimental studies, that sex hormones influence circadian rhythms, it is not known whether this is by a direct or an indirect effect on the SCN. Therefore, using immunocytochemistry in the present study, we investigated whether the human SCN expresses sex hormone receptors in 5 premenopausal women and 5 young men. SCN neurons appeared to contain estrogen receptor-alpha (ERalpha), estrogen receptor-beta (ERbeta) and progesterone receptors. Median ratings of ER immunoreactivity per individual and per gender group revealed a statistically significantly stronger nuclear ERalpha expression pattern in female SCN neurons (p sexual dimorphic tendency was observed for nuclear ERbeta (p > 0.1) and progesterone receptors (p > 0.7). These data seem to support previously reported functional and structural SCN differences in relation to sex and sexual orientation and indicate for the first time that estrogen and progesterone may act directly on neurons of the human biological clock. In addition, the present findings provide a potential neuroendocrine mechanism by which SHRT can act to improve or restore SCN-related rhythm disturbances, such as body temperature, sleep and mood. Copyright 2002 S. Karger AG, Basel

  16. Dust evolution with active galactic nucleus feedback in elliptical galaxies

    Science.gov (United States)

    Hirashita, Hiroyuki; Nozawa, Takaya

    2017-12-01

    We have recently suggested that dust growth in the cold gas phase dominates the dust abundance in elliptical galaxies while dust is efficiently destroyed in the hot X-ray emitting plasma (hot gas). In order to understand the dust evolution in elliptical galaxies, we construct a simple model that includes dust growth in the cold gas and dust destruction in the hot gas. We also take into account the effect of mass exchange between these two gas components induced by active galactic nucleus (AGN) feedback. We survey reasonable ranges of the relevant parameters in the model and find that AGN feedback cycles actually produce a variety in cold gas mass and dust-to-gas ratio. By comparing with an observational sample of nearby elliptical galaxies, we find that, although the dust-to-gas ratio varies by an order of magnitude in our model, the entire range of the observed dust-to-gas ratios is difficult to be reproduced under a single parameter set. Variation of the dust growth efficiency is the most probable solution to explain the large variety in dust-to-gas ratio of the observational sample. Therefore, dust growth can play a central role in creating the variation in dust-to-gas ratio through the AGN feedback cycle and through the variation in dust growth efficiency.

  17. Lateral cervical nucleus projections to periaqueductal gray matter in cat.

    Science.gov (United States)

    Mouton, Leonora J; Klop, Esther-Marije; Broman, Jonas; Zhang, Mengliang; Holstege, Gert

    2004-04-12

    The midbrain periaqueductal gray matter (PAG) integrates the basic responses necessary for survival of individuals and species. Examples are defense behaviors such as fight, flight, and freezing, but also sexual behavior, vocalization, and micturition. To control these behaviors the PAG depends on strong input from more rostrally located limbic structures, as well as from afferent input from the lower brainstem and spinal cord. Mouton and Holstege (2000, J Comp Neurol 428:389-410) showed that there exist at least five different groups of spino-PAG neurons, each of which is thought to subserve a specific function. The lateral cervical nucleus (LCN) in the upper cervical cord is not among these five groups. The LCN relays information from hair receptors and noxious information and projects strongly to the contralateral ventroposterior and posterior regions of thalamus and to intermediate and deep tectal layers. The question is whether the LCN also projects to the PAG. The present study in cat, using retrograde and anterograde tracing techniques, showed that neurons located in the lateral two-thirds of the LCN send fibers to the lateral part of the PAG, predominantly at rostrocaudal levels A0.6-P0.2. This part of the PAG is known to be involved in flight behavior. A concept is put forward according to which the LCN-PAG pathway alerts the animal about the presence of cutaneous stimuli that might represent danger, necessitating flight. J. Comp. Neurol. 471:434-445, 2004. Copyright 2004 Wiley-Liss, Inc.

  18. The mesencephalic nucleus of the trigeminal nerve and the SIDS.

    Science.gov (United States)

    Andrisani, Giovanni; Andrisani, Giorgia

    2015-01-01

    Sudden infant death syndrome (SIDS) is a major cause of infant mortality throughout the world, yet its cause and mechanism of action remain poorly understood. Here, we discuss a novel model of the etiology of SIDS which ties together what is known about the brain regions thought to be affected in SIDS infants with a defined neuroanatomical circuit and a documented preventative factor in young children. We propose that SIDS occurs due to a lack of sufficient development and plasticity of glutamatergic synapses in the mesencephalic nucleus of the trigeminal nerve (Me5) and reticular formation (RF) of the brainstem. This model is supported by evidence of brainstem dysfunction in SIDS as well as evidence of signaling through the Me5 and RF in another means of regulating cortical arousal. Furthermore, long-term plasticity of glutamatergic synapses is well known to play a critical role in learning and memory in other regions of the brain, implying that those mechanisms may also be relevant in the development of brainstem circuitry. This model clearly explains why SIDS deaths appear so suddenly with little pathological explanation and suggests a potentially novel way to prevent these deaths from occurring. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Nucleus accumbens shell moderates preference bias during voluntary choice behavior.

    Science.gov (United States)

    Jang, Hyeran; Jung, Kanghoon; Jeong, Jaehoon; Park, Sang Ki; Kralik, Jerald D; Jeong, Jaeseung

    2017-09-01

    The nucleus accumbens (NAc) shell lies anatomically at a critical intersection within the brain's reward system circuitry, however, its role in voluntary choice behavior remains unclear. Rats with electrolytic lesions in the NAc shell were tested in a novel foraging paradigm. Over a continuous two-week period they freely chose among four nutritionally identical but differently flavored food pellets by pressing corresponding levers. We examined the lesion's effects on three behavioral dynamics components: motivation (when to eat), preference bias (what to choose) and persistence (how long to repeat the same choice). The lesion led to a marked increase in the preference bias: i.e., increased selection of the most-preferred choice option, and decreased selection of the others. We found no effects on any other behavioral measures, suggesting no effect on motivation or choice persistence. The results implicate the NAc shell in moderating the instrumental valuation process by inhibiting excessive bias toward preferred choice options. © The Author (2017). Published by Oxford University Press.

  20. Depolarizing actions of hydrogen sulfide on hypothalamic paraventricular nucleus neurons.

    Directory of Open Access Journals (Sweden)

    C Sahara Khademullah

    Full Text Available Hydrogen sulfide (H2S is a novel neurotransmitter that has been shown to influence cardiovascular functions as well and corticotrophin hormone (CRH secretion. Since the paraventricular nucleus of the hypothalamus (PVN is a central relay center for autonomic and endocrine functions, we sought to investigate the effects of H2S on the neuronal population of the PVN. Whole cell current clamp recordings were acquired from the PVN neurons and sodium hydrosulfide hydrate (NaHS was bath applied at various concentrations (0.1, 1, 10, and 50 mM. NaHS (1, 10, and 50 mM elicited a concentration-response relationship from the majority of recorded neurons, with almost exclusively depolarizing effects following administration. Cells responded and recovered from NaHS administration quickly and the effects were repeatable. Input differences from baseline and during the NaHS-induced depolarization uncovered a biphasic response, implicating both a potassium and non-selective cation conductance. The results from the neuronal population of the PVN shed light on the possible physiological role that H2S has in autonomic and endocrine function.

  1. In vivo histamine voltammetry in the mouse premammillary nucleus.

    Science.gov (United States)

    Samaranayake, Srimal; Abdalla, Aya; Robke, Rhiannon; Wood, Kevin M; Zeqja, Anisa; Hashemi, Parastoo

    2015-06-07

    Histamine plays a major role in the mediation of allergic reactions such as peripheral inflammation. This classical monoamine is also a neurotransmitter involved in the central nervous system but its role in this context is poorly understood. Studying histamine neurotransmission is important due to its implications in many neurological disorders. The sensitivity, selectivity and high temporal resolution of fast scan cyclic voltammetry (FSCV) offer many advantages for studying electroactive neurotransmitters. Histamine has previously been studied with FSCV; however, the lack of a robust Faradaic electrochemical signal makes it difficult to selectively identify histamine in complex media, as found in vivo. In this work, we optimize an electrochemical waveform that provides a stimulation-locked and unique electrochemical signal towards histamine. We describe in vitro waveform optimization and a novel in vivo physiological model for stimulating histamine release in the mouse premammillary nucleus via stimulation of the medial forebrain bundle. We demonstrate that a robust signal can be used to effectively identify histamine and characterize its in vivo kinetics.

  2. Contour Detection of Leukocyte Cell Nucleus Using Morphological Image

    Science.gov (United States)

    Supriyanti, R.; Satrio, G. P.; Ramadhani, Y.; Siswandari, W.

    2017-04-01

    Leukocytes are blood cells that do not contain color pigments. Leukocyte function to the tool body’s defenses. Abnormal forms of leukocytes can be a sign of serious diseases such example is leukemia. Most laboratories still use cell morphology examination to assist the diagnosis of illness associated with white blood cells such example is leukemia because of limited resources, both infrastructure, and human resources as happens in developing nations, such as Indonesia. This examination is less expensive and quicker process. However, morphological review requires the expertise of a specialist clinical pathology were limited. This process is sometimes less valid cause in some cases trying to differentiate morphology blast cells into the type of myoblasts, lymphoblast, monoblast, or erythroblast thus potentially misdiagnosis. The goal of this research is to develop a detection device types of blood cells automatically as lower-priced, easy to use and accurate so that the tool can be distributed across all units in existing health services throughout Indonesia and in particular for remote areas. However, because the variables used in the identification of abnormal leukocytes are very complex, in this paper, we emphasize on the contour detection of leukocyte cell nucleus using the morphological image. The results show that this method is promising for further development.

  3. Nucleus accumbens shell moderates preference bias during voluntary choice behavior

    Science.gov (United States)

    Jang, Hyeran; Jung, Kanghoon; Jeong, Jaehoon; Park, Sang Ki; Kralik, Jerald D.

    2017-01-01

    Abstract The nucleus accumbens (NAc) shell lies anatomically at a critical intersection within the brain’s reward system circuitry, however, its role in voluntary choice behavior remains unclear. Rats with electrolytic lesions in the NAc shell were tested in a novel foraging paradigm. Over a continuous two-week period they freely chose among four nutritionally identical but differently flavored food pellets by pressing corresponding levers. We examined the lesion’s effects on three behavioral dynamics components: motivation (when to eat), preference bias (what to choose) and persistence (how long to repeat the same choice). The lesion led to a marked increase in the preference bias: i.e., increased selection of the most-preferred choice option, and decreased selection of the others. We found no effects on any other behavioral measures, suggesting no effect on motivation or choice persistence. The results implicate the NAc shell in moderating the instrumental valuation process by inhibiting excessive bias toward preferred choice options. PMID:28992274

  4. The hypothalamic arcuate nucleus and the control of peripheral substrates.

    Science.gov (United States)

    Joly-Amado, Aurélie; Cansell, Céline; Denis, Raphaël G P; Delbes, Anne-Sophie; Castel, Julien; Martinez, Sarah; Luquet, Serge

    2014-10-01

    The arcuate nucleus (ARC) of the hypothalamus is particularly regarded as a critical platform that integrates circulating signals of hunger and satiety reflecting energy stores and nutrient availability. Among ARC neurons, pro-opiomelanocortin (POMC) and agouti-related protein and neuropeptide Y (NPY/AgRP neurons) are considered as two opposing branches of the melanocortin signaling pathway. Integration of circulating signals of hunger and satiety results in the release of the melanocortin receptor ligand α-melanocyte-stimulating hormone (αMSH) by the POMC neurons system and decreases feeding and increases energy expenditure. The orexigenic/anabolic action of NPY/AgRP neurons is believed to rely essentially on their inhibitory input onto POMC neurons and second-orders targets. Recent updates in the field have casted a new light on the role of the ARC neurons in the coordinated regulation of peripheral organs involved in the control of nutrient storage, transformation and substrate utilization independent of food intake. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. The pedunculopontine tegmental nucleus and the nucleus basalis magnocellularis: Do both have a role in sustained attention?

    Directory of Open Access Journals (Sweden)

    Latimer Mary P

    2008-01-01

    Full Text Available Abstract Background It is well established that nucleus basalis magnocellularis (NbM lesions impair performance on tests of sustained attention. Previous work from this laboratory has also demonstrated that pedunculopontine tegmental nucleus (PPTg lesioned rats make more omissions on a test of sustained attention, suggesting that it might also play a role in mediating this function. However, the results of the PPTg study were open to alternative interpretation. We aimed to resolve this by conducting a detailed analysis of the effects of damage to each brain region in the same sustained attention task used in our previous work. Rats were trained in the task before surgery and post-surgical testing examined performance in response to unpredictable light signals of 1500 ms and 4000 ms duration. Data for PPTg lesioned rats were compared to control rats, and rats with 192 IgG saporin infusions centred on the NbM. In addition to operant data, video data of rats' performance during the task were also analysed. Results Both lesion groups omitted trials relative to controls but the effect was milder and transient in NbM rats. The number of omitted trials decreased in all groups when tested using the 4000 ms signal compared to the 1500 ms signal. This confirmed previous findings for PPTg lesioned rats. Detailed analysis revealed that the increase in omissions in PPTg rats was not a consequence of motor impairment. The video data (taken on selected days showed reduced lever orientation in PPTg lesioned rats, coupled with an increase in unconditioned behaviours such as rearing and sniffing. In contrast NbM rats showed evidence of inadequate lever pressing. Conclusion The question addressed here is whether the PPTg and NbM both have a role in sustained attention. Rats bearing lesions of either structure showed deficits in the test used. However, we conclude that the most parsimonious explanation for the deficit observed in PPTg rats is inadequate response

  6. Kleptochloroplast Enlargement, Karyoklepty and the Distribution of the Cryptomonad Nucleus in Nusuttodinium (= Gymnodinium) aeruginosum (Dinophyceae).

    Science.gov (United States)

    Onuma, Ryo; Horiguchi, Takeo

    2015-05-01

    The unarmoured freshwater dinoflagellate Nusuttodinium (= Gymnodinium) aeruginosum retains a cryptomonad-derived kleptochloroplast and nucleus, the former of which fills the bulk of its cell volume. The paucity of studies following morphological changes to the kleptochloroplast with time make it unclear how the kleptochloroplast enlarges and why the cell ultimately loses the cryptomonad nucleus. We observed, both at the light and electron microscope level, morphological changes to the kleptochloroplast incurred by the enlargement process under culture conditions. The distribution of the cryptomonad nucleus after host cell division was also investigated. The volume of the kleptochloroplast increased more than 20-fold, within 120h of ingestion of the cryptomonad. Host cell division was not preceded by cryptomonad karyokinesis so that only one of the daughter cells inherited a cryptomonad nucleus. The fate of all daughter cells originating from a single cell through five generations was closely monitored, and this observation revealed that the cell that inherited the cryptomonad nucleus consistently possessed the largest kleptochloroplast for that generation. Therefore, this study suggests that some important cryptomonad nucleus division mechanism is lost during ingestion process, and that the cryptomonad nucleus carries important information for the enlargement of the kleptochloroplast. Copyright © 2015 Elsevier GmbH. All rights reserved.

  7. Shape evolution of 72,74Kr with temperature in covariant density functional theory

    Science.gov (United States)

    Zhang, Wei; Niu, Yi-Fei

    2017-09-01

    The rich phenomena of deformations in neutron-deficient krypton isotopes, such as shape evolution with neutron number and shape coexistence, have attracted the interest of nuclear physicists for decades. It is interesting to study such shape phenomena using a novel way, e.g. by thermally exciting the nucleus. In this work, we develop the finite temperature covariant density functional theory for axially deformed nuclei with the treatment of pairing correlations by the BCS approach, and apply this approach for the study of shape evolution in 72,74Kr with increasing temperature. For 72Kr, with temperature increasing, the nucleus firstly experiences a relatively quick weakening in oblate deformation at temperature T ∼0.9 MeV, and then changes from oblate to spherical at T ∼2.1 MeV. For 74Kr, its global minimum is at quadrupole deformation β 2 ∼ ‑0.14 and abruptly changes to spherical at T∼ 1.7 MeV. The proton pairing transition occurs at critical temperature 0.6 MeV following the rule T c=0.6Δ p(0), where Δ p(0) is the proton pairing gap at zero temperature. The signatures of the above pairing transition and shape changes can be found in the specific heat curve. The single-particle level evolutions with temperature are presented. Supported by National Natural Science Foundation of China (11105042, 11305161, 11505157), Open Fund of Key Laboratory of Time and Frequency Primary Standards, CAS, and Support from Henan Administration of Foreign Experts Affairs

  8. The Efferent Connections Of The Nucleus Of The Optic Tract And The Superior Colliculus In The Rabbit

    NARCIS (Netherlands)

    Holstege, Gert; Collewijn, Han

    1982-01-01

    3H-leucine injections were made in tectal and pretectal areas in the rabbit. After injections in the nucleus of the optic tract (NOT) labeled fibers were distributed bilaterally to the superior colliculus, the dorsal part of the medial geniculate nucleus (MGd), and the pulvinar nucleus, and

  9. Thermodynamics of droplet formation around a soluble condensation nucleus in the atmosphere of a solvent vapor.

    Science.gov (United States)

    Shchekin, A K; Shabaev, I V; Rusanov, A I

    2008-12-07

    An expression for the work of formation of a spherical droplet condensing on a soluble condensation nucleus out of a solvent vapor is derived. The dependence of the formation work on the solvent vapor chemical potential and the droplet and the nucleus residue sizes is analyzed. The balance of the solute matter between the liquid film and the nucleus residue and the effect of overlapping the surface layers of the thin film have been taken into account. It is shown that the equations of the chemical equilibrium of a solute and a solvent in the droplet, resulting from the generating properties of the formation work, coincide with the generalized Gibbs-Kelvin-Kohler and Ostwald-Freundlich equations. The numerical solution of these equations at a fixed number of molecules of the nucleus matter (at an initial size of the nucleus specified) has been performed in the case of the solvent vapor undersaturated over the bulk liquid solvent phase. The solution links the equilibrium sizes of the droplet and the soluble nucleus residue with the chemical potential or the pressure of the solvent vapor saturated over the droplet. It also determines the limiting sizes of the droplet with small nucleus residue above which the chemical equilibrium of the residue surface and the solution film does not exist. The existence of the limiting sizes is responsible for the specific behavior of the droplet thermodynamic characteristics and the work of droplet formation at deliquescence transition from the droplet state with a partly dissolved nucleus to the state of complete dissolution of the nucleus.

  10. Bradycardic effects mediated by activation of G protein-coupled estrogen receptor in rat nucleus ambiguus.

    Science.gov (United States)

    Brailoiu, G Cristina; Arterburn, Jeffrey B; Oprea, Tudor I; Chitravanshi, Vineet C; Brailoiu, Eugen

    2013-03-01

    The G protein-coupled estrogen receptor (GPER) has been identified in several brain regions, including cholinergic neurons of the nucleus ambiguus, which are critical for parasympathetic cardiac regulation. Using calcium imaging and electrophysiological techniques, microinjection into the nucleus ambiguus and blood pressure measurement, we examined the in vitro and in vivo effects of GPER activation in nucleus ambiguus neurons. A GPER selective agonist, G-1, produced a sustained increase in cytosolic Ca(2+) concentration in a concentration-dependent manner in retrogradely labelled cardiac vagal neurons of nucleus ambiguus. The increase in cytosolic Ca(2+) produced by G-1 was abolished by pretreatment with G36, a GPER antagonist. G-1 depolarized cultured cardiac vagal neurons of the nucleus ambiguus. The excitatory effect of G-1 was also identified by whole-cell visual patch-clamp recordings in nucleus ambiguus neurons, in medullary slices. To validate the physiological relevance of our in vitro studies, we carried out in vivo experiments. Microinjection of G-1 into the nucleus ambiguus elicited a decrease in heart rate; the effect was blocked by prior microinjection of G36. Systemic injection of G-1, in addition to a previously reported decrease in blood pressure, also reduced the heart rate. The G-1-induced bradycardia was prevented by systemic injection of atropine, a muscarinic antagonist, or by bilateral microinjection of G36 into the nucleus ambiguus. Our results indicate that GPER-mediated bradycardia occurs via activation of cardiac parasympathetic neurons of the nucleus ambiguus and support the involvement of the GPER in the modulation of cardiac vagal tone.

  11. Calcium fluxes cause nuclear shrinkage and the translocation of phospholipase C-delta1 into the nucleus.

    Science.gov (United States)

    Okada, Masashi; Taguchi, Katsutoshi; Maekawa, Shohei; Fukami, Kiyoko; Yagisawa, Hitoshi

    2010-03-26

    Phospholipase C-delta1 (PLCdelta1) is the most fundamental form of the eukaryotic PLC and thought to play important roles in the regulation of cells. We previously reported that PLCdelta1 shuttles between the cytoplasm and nucleus, and an influx of Ca2+ triggers the nuclear import of PLCdelta1 via Ca2+-dependent interaction with importin beta1, although the physiological meaning of this is unclear. Here we have examined the distribution of PLCdelta1 using primary cultures of rat hippocampal neurons. Treatment of 7DIV neurons with ionomycin or thapsigargin caused the nuclear localization of PLCdelta1 as has been observed in other cell lines. Similar results were obtained with neurons treated with glutamate, suggesting that the nuclear localization of PLCdelta1 plays some roles in excitotoxicity associated with ischemic stress. Generally, cells undergoing ischemic or hypoxic cell death show nuclear shrinkage. We confirmed that a massive influx of Ca2+ caused similar results. Furthermore, overexpression of GFP-PLCdelta1 facilitated ionomycin-induced nuclear shrinkage in embryonic fibroblasts derived from PLCdelta1 gene-knockout mice (PLCdelta1KO-MEF). By contrast, an E341A mutant that cannot bind with importin beta1 and be imported into the nucleus by ionomycin and also lacks enzymatic activity did not cause nuclear shrinkage in PLCdelta1KO-MEF. Nuclear translocation and the PLC activity of PLCdelta1, therefore, may regulate the nuclear shape by controlling the nuclear scaffold during stress-induced cell death caused by high levels of Ca2+. 2010 Elsevier Ireland Ltd. All rights reserved.

  12. Shape analysis of synthetic diamond

    CERN Document Server

    Mullan, C

    1997-01-01

    Two-dimensional images of synthetic industrial diamond particles were obtained using a camera, framegrabber and PC-based image analysis software. Various methods for shape quantification were applied, including two-dimensional shape factors, Fourier series expansion of radius as a function of angle, boundary fractal analysis, polygonal harmonics, and comer counting methods. The shape parameter found to be the most relevant was axis ratio, defined as the ratio of the minor axis to the major axis of the ellipse with the same second moments of area as the particle. Axis ratio was used in an analysis of the sorting of synthetic diamonds on a vibrating table. A model was derived based on the probability that a particle of a given axis ratio would travel to a certain bin. The model described the sorting of bulk material accurately but it was found not to be applicable if the shape mix of the feed material changed dramatically. This was attributed to the fact that the particle-particle interference was not taken int...

  13. How Faults Shape the Earth.

    Science.gov (United States)

    Bykerk-Kauffman, Ann

    1992-01-01

    Presents fault activity with an emphasis on earthquakes and changes in continent shapes. Identifies three types of fault movement: normal, reverse, and strike faults. Discusses the seismic gap theory, plate tectonics, and the principle of superposition. Vignettes portray fault movement, and the locations of the San Andreas fault and epicenters of…

  14. Cell shape: taking the heat.

    Science.gov (United States)

    Kunda, Patricia; Rohn, Jennifer L; Baum, Buzz

    2008-06-03

    Preservation of cell architecture under physically stressful conditions is a basic requirement for many biological processes and is critical for mechanosensory systems built to translate subtle changes in cell shape into changes in organism behaviour. A new study reveals how an extracellular protein--Spam--helps mechanosensory organs in the fruit fly to withstand the effects of the water loss that accompanies heat shock.

  15. The pear-shaped bladder.

    Science.gov (United States)

    Ambos, M A; Bosniak, M A; Lefleur, R S; Madayag, M A

    1977-01-01

    The tear-drop or pear-shaped bladder was originally described in cases of pelvic hematoma. It may also be seen, however, with a variety of other entities, including pelvic lipomatosis, inferior vena cava occlusion, lymphocysts, and enlarged pelvic lymph nodes. Pertinent radiographic findings of these conditions are reviewed.

  16. A stereological study of the mediodorsal thalamic nucleus in Down syndrome

    DEFF Research Database (Denmark)

    Karlsen, A S; Korbo, S; Uylings, H B M

    2014-01-01

    The total number of neurons and glial cells in the mediodorsal thalamic (MDT) nucleus of four aged females with Down syndrome (DS; mean age 69years) was estimated and compared to six age- and sex-matched controls. The MDT nucleus was delineated on coronal sections, and cell numbers (large and small...... neurons, oligodendrocytes, and astrocytes) were estimated using the optical fractionator technique. The DS brains had an average of 3.41×10(6) total neurons in the MDT nucleus in contrast to 5.97×10(6) in the controls, with no overlap (2p=0.004), affecting large (projecting) and small (local inhibitory...

  17. A role of nucleus accumbens dopamine receptors in the nucleus accumbens core, but not shell, in fear prediction error.

    Science.gov (United States)

    Li, Susan S Y; McNally, Gavan P

    2015-08-01

    Two experiments used an associative blocking design to study the role of dopamine receptors in the nucleus accumbens shell (AcbSh) and core (AcbC) in fear prediction error. Rats in the experimental groups were trained to a visual fear-conditioned stimulus (conditional stimulus [CS]) A in Stage I, whereas rats in the control groups were not. In Stage II, all rats received compound fear conditioning of the visual CSA and an auditory CSB. Rats were later tested for their fear responses to CSB. All rats received microinjections of saline or the D1-D2 receptor antagonist cis-(z)-flupenthixol prior to Stage II. These microinjections targeted either the AcbSh (Experiment 1) or the AcbC (Experiment 2). In each experiment, Stage I fear conditioning of CSA blocked fear learning to CSB. Microinjection of cis-(z)-flupenthixol (10 or 20 μg) into the AcbSh (Experiment 1) had no effect on fear learning or associative blocking. In contrast, microinjection of cis-(z)-flupenthixol (10 or 20 μg) into the AcbC (Experiment 2) attenuated blocking and so enabled fear learning to CSB. These results identify the AcbC as the critical locus for dopamine receptor contributions to fear prediction error and the associative blocking of fear learning. (c) 2015 APA, all rights reserved).

  18. SHAPE CHARACTERIZATION OF CONCRETE AGGREGATE

    Directory of Open Access Journals (Sweden)

    Jing Hu

    2011-05-01

    Full Text Available As a composite material, the performance of concrete materials can be expected to depend on the properties of the interfaces between its two major components, aggregate and cement paste. The microstructure at the interfacial transition zone (ITZ is assumed to be different from the bulk material. In general, properties of conventional concrete have been found favoured by optimum packing density of the aggregate. Particle size is a common denominator in such studies. Size segregation in the ITZ among the binder particles in the fresh state, observed in simulation studies by concurrent algorithm-based SPACE system, additionally governs density as well as physical bonding capacity inside these shell-like zones around aggregate particles. These characteristics have been demonstrated qualitatively pertaining also after maturation of the concrete. Such properties of the ITZs have direct impact on composite properties. Despite experimental approaches revealed effects of aggregate grain shape on different features of material structure (among which density, and as a consequence on mechanical properties, it is still an underrated factor in laboratory studies, probably due to the general feeling that a suitable methodology for shape characterization is not available. A scientific argument hindering progress is the interconnected nature of size and shape. Presently, a practical problem preventing shape effects to be emphasized is the limitation of most computer simulation systems in concrete technology to spherical particles. New developments at Delft University of Technology will make it possible in the near future to generate jammed states, or other high-density fresh particle mixtures of non-spherical particles, which thereupon can be subjected to hydration algorithms. This paper will sketch the outlines of a methodological approach for shape assessment of loose (non-embedded aggregate grains, and demonstrate its use for two types of aggregate, allowing

  19. $N-N$, $P_{T}-N$ and $P_{T}-P_{T}$ fluctuations in nucleus-nucleus collisions at the NA61/SHINE experiment arXiv

    CERN Document Server

    Andronov, Evgeny

    The NA61/SHINE experiment aims to discover the critical point of strongly interacting matter and study the properties of the onset of deconfinement. For these goals a scan of the two dimensional phase diagram ($T-\\mu_{B}$) is being performed at the SPS by measurements of hadron production in proton-proton, proton-nucleus and nucleus-nucleus interactions as a function of collision energy. This paper presents preliminary results from Be+Be collisions on pseudorapidity dependences of transverse momentum and multiplicity fluctuations expressed in terms of strongly intensive quantities. It is shown that non-trivial effects evolve from the Poissonian-like fluctuations for small pseudorapidity intervals with expansion of the acceptance. These fluctuations are supposed to be sensitive to the existence of the critical point. The results will be compared to the predictions from the EPOS model.

  20. Atmospheric Aerosols: Cloud Condensation Nucleus Activity of Selected Organic Molecules

    Science.gov (United States)

    Rosenorn, T.; Henning, S.; Hartz, K. H.; Kiss, G.; Pandis, S.; Bilde, M.

    2005-12-01

    Gas/particle partitioning of vapors in the atmosphere plays a major role in both climate through micro meteorology and in the physical and chemical processes of a single particle. This work has focused on the cloud droplet activation of a number of pure and mixed compounds. The means used to investigate these processes have been the University of Copenhagen cloud condensation nucleus counter setup and the Carnegie Mellon University CCNC setup. The importance of correct water activity modeling has been addressed and it has been pointed out that the molecular mass is an important parameter to consider when choosing model compounds for cloud activation models. It was shown that both traditional Kohler theory and Kohler theory modified to account for limited solubility reproduce measurements of soluble compounds well. For less soluble compounds it is necessary to use Kohler theory modified to account for limited solubility. It was also shown that this works for mixtures of compounds containing both inorganic salts and dicarboxylic acids. It has also been shown that particle phase and humidity history is important for activation behavior of particles consisting of two slightly soluble organic substances (succinic and adipic acid) and a soluble salt (NaCl). Model parameters for terpene oxidation product cloud activation have been derived. These are based on two sets of average parameters covering monoterpene oxidation products and sesquiterpene oxidation products. All parameters except the solubility were estimated and an effective solubility was calculated as the fitting parameter. The average solubility of the model compound found for mono terpene oxidation products is similar to those of sodium chloride and ammonium sulfate; however the higher molecular weight leads to a slightly higher activation diameter at fixed supersaturation. On a molar basis the monoterpene oxidation products show a 1.5 times higher effective solubility than the sesquiterpene oxidation products.

  1. Visual signal processing in the macaque lateral geniculate nucleus.

    Science.gov (United States)

    Seim, Thorstein; Valberg, Arne; Lee, Barry B

    2012-03-01

    Comparisons of S- or prepotential activity, thought to derive from a retinal ganglion cell afferent, with the activity of relay cells of the lateral geniculate nucleus (LGN) have sometimes implied a loss, or leak, of visual information. The idea of the "leaky" relay cell is reconsidered in the present analysis of prepotential firing and LGN responses of color-opponent cells of the macaque LGN to stimuli varying in size, relative luminance, and spectral distribution. Above a threshold prepotential spike frequency, called the signal transfer threshold (STT), there is a range of more than 2 log units of test field luminance that has a 1:1 relationship between prepotential- and LGN-cell firing rates. Consequently, above this threshold, the LGN cell response can be viewed as an extension of prepotential firing (a "nonleaky relay cell"). The STT level decreased when the size of the stimulus increased beyond the classical receptive field center, indicating that the LGN cell is influenced by factors other than the prepotential input. For opponent ON cells, both the excitatory and the inhibitory response decreased similarly when the test field size increased beyond the center of the receptive field. These findings have consequences for the modeling of LGN cell responses and transmission of visual information, particularly for small fields. For instance, for LGN ON cells, information in the prepotential intensity-response curve for firing rates below the STT is left to be discriminated by OFF cells. Consequently, for a given light adaptation, the STT improves the separation of the response range of retinal ganglion cells into "complementary" ON and OFF pathways.

  2. Processing of emotional information in the human subthalamic nucleus.

    Science.gov (United States)

    Buot, Anne; Welter, Marie-Laure; Karachi, Carine; Pochon, Jean-Baptiste; Bardinet, Eric; Yelnik, Jérôme; Mallet, Luc

    2013-12-01

    The subthalamic nucleus (STN) is an efficient target for treating patients with Parkinson's disease as well as patients with obsessive-compulsive disorder (OCD) using high frequency stimulation (HFS). In both Parkinson's disease and OCD patients, STN-HFS can trigger abnormal behaviours, such as hypomania and impulsivity. To investigate if this structure processes emotional information, and whether it depends on motor demands, we recorded subthalamic local field potentials in 16 patients with Parkinson's disease using deep brain stimulation electrodes. Recordings were made with and without dopaminergic treatment while patients performed an emotional categorisation paradigm in which the response varied according to stimulus valence (pleasant, unpleasant and neutral) and to the instruction given (motor, non-motor and passive). Pleasant, unpleasant and neutral stimuli evoked an event related potential (ERP). Without dopamine medication, ERP amplitudes were significantly larger for unpleasant compared with neutral pictures, whatever the response triggered by the stimuli; and the magnitude of this effect was maximal in the ventral part of the STN. No significant difference in ERP amplitude was observed for pleasant pictures. With dopamine medication, ERP amplitudes were significantly increased for pleasant compared with neutral pictures whatever the response triggered by the stimuli, while ERP amplitudes to unpleasant pictures were not modified. These results demonstrate that the ventral part of the STN processes the emotional valence of stimuli independently of the motor context and that dopamine enhances processing of pleasant information. These findings confirm the specific involvement of the STN in emotional processes in human, which may underlie the behavioural changes observed in patients with deep brain stimulation.

  3. Encoding of aversion by dopamine and the nucleus accumbens

    Directory of Open Access Journals (Sweden)

    James Edgar Mccutcheon

    2012-09-01

    Full Text Available Adaptive motivated behavior requires rapid discrimination between beneficial and harmful stimuli. Such discrimination leads to the generation of either an approach or rejection response, as appropriate, and enables organisms to maximize reward and minimize punishment. Classically, the nucleus accumbens (NAc and the dopamine projection to it are considered an integral part of the brain’s reward circuit, i.e., they direct approach and consumption behaviors and underlie positive reinforcement. This reward-centered framing ignores important evidence about the role of this system in encoding aversive events. One reason for bias towards reward is the difficulty in designing experiments in which animals repeatedly experience punishments; another is the challenge in dissociating the response to an aversive stimulus itself from the reward/relief experienced when an aversive stimulus is terminated. Here, we review studies that employ techniques with sufficient time resolution to measure responses in ventral tegmental area (VTA and NAc to aversive stimuli as they are delivered. We also present novel findings showing that the same stimulus – intraoral infusion of sucrose – has differing effects on NAc shell dopamine release depending on the prior experience. Here, for some rats, sucrose was rendered aversive by explicitly pairing it with malaise in a conditioned taste aversion paradigm. Thereafter, sucrose infusions led to a suppression of dopamine with a similar magnitude and time course to intra-oral infusions of a bitter quinine solution. The results are discussed in the context of regional differences in dopamine signaling and the implications of a pause in phasic dopamine release within the NAc shell. Together with our data, the emerging literature suggests an important role for differential phasic dopamine signaling in aversion versus reward.

  4. Rhythmic Coupling Among Cells in the Suprachiasmatic Nucleus

    Science.gov (United States)

    Colwell, Christopher S.

    2008-01-01

    In mammals, the part of the nervous system responsible for most circadian behavior can be localized to a pair of structures in the hypothalamus known as the suprachiasmatic nucleus (SCN). Previous studies suggest that the basic mechanism responsible for the generation of these rhythms is intrinsic to individual cells. There is also evidence that the cells within the SCN are coupled to one another and that this coupling is important for the normal functioning of the circadian system. One mechanism that mediates coordinated electrical activity is direct electrical connections between cells formed by gap junctions. In the present study, we used a brain slice preparation to show that developing SCN cells are dye coupled. Dye coupling was observed in both the ventrolateral and dorsomedial subdivisions of the SCN and was blocked by application of a gap junction inhibitor, halothane. Dye coupling in the SCN appears to be regulated by activity-dependent mechanisms as both tetrodotoxin and the GABAA agonist muscimol inhibited the extent of coupling. Furthermore, acute hyperpolarization of the membrane potential of the original biocytin-filled neuron decreased the extent of coupling. SCN cells were extensively dye coupled during the day when the cells exhibit synchronous neural activity but were minimally dye coupled during the night when the cells are electrically silent. Immunocytochemical analysis provides evidence that a gap-junction—forming protein, connexin32, is expressed in the SCN of postnatal animals. Together the results are consistent with a model in which gap junctions provide a means to couple SCN neurons on a circadian basis. PMID:10861563

  5. Search for and study of linking transitions between super- and normal deformed wells in the {sup 151}Tb nucleus; Recherche et etude de transitions de liaison entre les puits super- et normalement deformes dans le noyau {sup 151}Tb

    Energy Technology Data Exchange (ETDEWEB)

    Robin, J

    2003-12-01

    While the superdeformation phenomenon has been observed many times in different mass regions, the excitation energy and angular momentum are not known for most of the superdeformed bands, mainly in the A {approx} 150 mass region. We have thus undertaken the search for and study of linking transitions between super and normal deformed potential wells in the Tb{sup 151} nucleus with the EUROBALL-IV spectrometer based at the subatomic research institute of Strasbourg. This nucleus presents the peculiarity of having an excited superdeformed band identical to the yrast one of Dy{sup 152}, which has recently been linked to normal deformed states. As the Dy{sup 152} nucleus exhibits a shape coexistence in the first potential well, we have also searched for collective rotational bands with prolate but moderate shape, coexisting with the oblate structure of Tb{sup 151}. The discovery of new superdeformed bands in the Tb{sup 151,152} isotopes, the extension to lower and higher spins of the previously known bands, and mean field calculations with a deformed Woods-Saxon potential have contributed to improve our knowledge as well as raise new questions on the orbitals configuration assignments of these bands. (author)

  6. System-size dependence of strangeness production in nucleus-nucleus collisions at $\\sqrt{s_{NN}}$ = 17.3 GeV

    CERN Document Server

    Alt, C; Baatar, B; Barna, D; Bartke, J; Betev, L; Bialkowska, H; Billmeier, A; Blume, C; Boimska, B; Botje, M; Bracinik, J; Bramm, R; Brun, R; Buncic, P; Cerny, V; Christakoglou, P; Chvala, O; Cramer, J G; Csató, P; Darmenov, N; Dimitrov, A; Dinkelaker, P; Eckardt, V; Farantatos, G; Flierl, D; Fodor, Z; Foka, P; Freund, P; Friese, V; Gál, J; Gazdzicki, M; Georgopoulos, G; Gladysz-Dziadus, E; Grebieszkow, K; Hegyi, S; Höhne, C; Kadija, K; Karev, A; Kliemant, M; Kniege, S; Kolesnikov, V I; Kollegger, T; Kornas, E; Korus, R; Kowalski, M; Kraus, I; Kreps, M; Van Leeuwen, M; Lévai, Peter; Litov, L; Lungwitz, B; Makariev, M; Malakhov, A I; Markert, C; Mateev, M; Mayes, B W; Melkumov, G L; Meurer, C; Mischke, A; Mitrovski, M; Molnár, J; Mrówczynski, S; Pálla, G; Panagiotou, A D; Panayotov, D; Petridis, A; Pikna, M; Pinsky, L; Pühlhofer, F; Reid, J G; Renfordt, R; Richard, A; Roland, C; Roland, G; Rybczynski, M; Rybicki, A; Sandoval, A; Sann, H; Schmitz, N; Seyboth, P; Siklér, F; Sitár, B; Skrzypczak, E; Stefanek, G; Stock, R; Ströbele, H; Susa, T; Szentpétery, I; Sziklai, J; Trainor, T A; Trubnikov, V; Varga, D; Vassiliou, M; Veres, G I; Vesztergombi, G; Vranic, D; Wetzler, A; Wlodarczyk, Z; Yoo, I K; Zaranek, J; Zimányi, J

    2005-01-01

    Emission of pi plus or minus , K plus or minus , phi, and Lambda was measured in near-central C + C and Si + Si collisions at 158 AGeV beam energy. Together with earlier data for p + p, S + S, and Pb + Pb, the system-size dependence of relative strangeness production in nucleus-nucleus collisions is obtained. Its fast rise and the saturation observed at about 60 participating nucleons can be understood as the onset of the formation of coherent systems of increasing size. copy 2005 The American Physical Society.

  7. Superdeformation in Asymmetric N$>$Z Nucleus $^{40}$Ar

    CERN Document Server

    Ideguchi, E; Morikawa, T; Oshima, M; Koizumi, M; Toh, Y; Kimura, A; Harada, H; Furutaka, K; Nakamura, S; Kitatani, F; Hatsukawa, Y; Shizuma, T; Sugawara, M; Miyatake, H; Watanabe, Y X; Hirayama, Y; Oi, M

    2009-01-01

    A rotational band with five $\\gamma$-ray transitions ranging from 2$^{+}$ to 12$^{+}$ states was identified in $^{40}$Ar. This band is linked through $\\gamma$ transitions from the excited 2$^{+}$, 4$^{+}$ and 6$^{+}$ levels to the low-lying states; this determines the excitation energy and the spin-parity of the band. The deduced transition quadrupole moment of 1.45$^{+0.49}_{-0.31} eb$ indicates that the band has a superdeformed shape. The nature of the band is revealed by cranked Hartree--Fock--Bogoliubov calculations and a multiparticle--multihole configuration is assigned to the band.

  8. Superdeformation in asymmetric N>Z nucleus {sup 40}Ar

    Energy Technology Data Exchange (ETDEWEB)

    Ideguchi, E., E-mail: ideguchi@cns.s.u-tokyo.ac.j [Center for Nuclear Study, University of Tokyo, Wako, Saitama 351-0198 (Japan); Ota, S. [Center for Nuclear Study, University of Tokyo, Wako, Saitama 351-0198 (Japan); Morikawa, T. [Department of Physics, Kyushu University, Hakozaki, Fukuoka 812-8581 (Japan); Oshima, M.; Koizumi, M.; Toh, Y.; Kimura, A.; Harada, H.; Furutaka, K.; Nakamura, S.; Kitatani, F.; Hatsukawa, Y.; Shizuma, T. [Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan); Sugawara, M. [Chiba Institute of Technology, Narashino, Chiba 275-0023 (Japan); Miyatake, H.; Watanabe, Y.X.; Hirayama, Y. [Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Oi, M. [Institute of Natural Sciences, Senshu University, Tokyo 101-8425 (Japan)

    2010-03-15

    A rotational band with five gamma-ray transitions ranging from 2{sup +} to 12{sup +} states was identified in {sup 40}Ar. This band is linked through gamma transitions from the excited 2{sup +}, 4{sup +} and 6{sup +} levels to the low-lying states; this determines the excitation energy and the spin-parity of the band. The deduced transition quadrupole moment of 1.45{sub -0.31}{sup +0.49}+-0.15 eb indicates that the band has a superdeformed shape. The nature of the band is revealed by cranked Hartree-Fock-Bogoliubov calculations and a multiparticle-multihole configuration is assigned to the band.

  9. Effect of Decompression Therapy Combined with Joint Mobilization on Patients with Lumbar Herniated Nucleus Pulposus

    National Research Council Canada - National Science Library

    Lee, Younghwa; Lee, Chang-Ryeol; Cho, Misuk

    2012-01-01

    [Purpose] The purpose of this study was to examine the effects of decompression therapy combined with joint mobilization on the pain and range of motion of patients with lumbar herniated nucleus pulposus. [Subjects...

  10. The Developmental Remodeling of Eye‐Specific Afferents in the Ferret Dorsal Lateral Geniculate Nucleus

    National Research Council Canada - National Science Library

    Speer, Colenso M; Mikula, Shawn; Huberman, Andrew D; Chapman, Barbara

    2010-01-01

    Ferret vision mandala. This photo was created by overlapping multiple images of a horizontal section through the central portion of the adult ferret lateral geniculate nucleus and superior colliculus...

  11. Decreased number of oxytocin neurons in the paraventricular nucleus of the human hypothalamus in AIDS

    NARCIS (Netherlands)

    Purba, J. S.; Hofman, M. A.; Portegies, P.; Troost, D.; Swaab, D. F.

    1993-01-01

    The number of immunocytochemically identified vasopressin (AVP) and oxytocin (OXT) neurons was determined morphometrically in the paraventricular nucleus of the hypothalamus of 20 acquired immunodeficiency syndrome (AIDS) patients and 10 controls. The AIDS group consisted of 14 homosexual males (age

  12. Facebook usage on smartphones and gray matter volume of the nucleus accumbens.

    Science.gov (United States)

    Montag, Christian; Markowetz, Alexander; Blaszkiewicz, Konrad; Andone, Ionut; Lachmann, Bernd; Sariyska, Rayna; Trendafilov, Boris; Eibes, Mark; Kolb, Julia; Reuter, Martin; Weber, Bernd; Markett, Sebastian

    2017-06-30

    A recent study has implicated the nucleus accumbens of the ventral striatum in explaining why online-users spend time on the social network platform Facebook. Here, higher activity of the nucleus accumbens was associated with gaining reputation on social media. In the present study, we touched a related research field. We recorded the actual Facebook usage of N=62 participants on their smartphones over the course of five weeks and correlated summary measures of Facebook use with gray matter volume of the nucleus accumbens. It appeared, that in particular higher daily frequency of checking Facebook on the smartphone was robustly linked with smaller gray matter volumes of the nucleus accumbens. The present study gives additional support for the rewarding aspects of Facebook usage. Moreover, it shows the feasibility to include real life behavior variables in human neuroscientific research. Copyright © 2017 Elsevier B.V. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    Venkatesh Rengaraj

    2009-01-01

    Full Text Available 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 makes the rest of the steps of MSICS comfortable. Use of trypan blue in white and brown cataracts makes the capsulorrhexis and prolapse simple and safe. Extra caution should be taken in cases with hypermature cataracts with weak zonules and subluxated cataracts.

  14. c-Met must translocate to the nucleus to initiate calcium signals.

    Science.gov (United States)

    Gomes, Dawidson A; Rodrigues, Michele A; Leite, M Fatima; Gomez, Marcus V; Varnai, Peter; Balla, Tamas; Bennett, Anton M; Nathanson, Michael H

    2008-02-15

    Hepatocyte growth factor (HGF) is important for cell proliferation, differentiation, and related activities. HGF acts through its receptor c-Met, which activates downstream signaling pathways. HGF binds to c-Met at the plasma membrane, where it is generally believed that c-Met signaling is initiated. Here we report that c-Met rapidly translocates to the nucleus upon stimulation with HGF. Ca(2+) signals that are induced by HGF result from phosphatidylinositol 4,5-bisphosphate hydrolysis and inositol 1,4,5-trisphosphate formation within the nucleus rather than within the cytoplasm. Translocation of c-Met to the nucleus depends upon the adaptor protein Gab1 and importin beta1, and formation of Ca(2+) signals in turn depends upon this translocation. HGF may exert its particular effects on cells because it bypasses signaling pathways in the cytoplasm to directly activate signaling pathways in the nucleus.

  15. Effects of damage to median raphe nucleus on ingestive behavior and wheel running activity.

    Science.gov (United States)

    Shahid Salles, M S; Heym, J; Gladfelter, W E

    1979-01-01

    The effects of damage to the median raphe nucleus on the ingestive behavior and wheel running activity of rats were studied. This nucleus was damaged by the placement of either electrolytic or chemical (5,7-dihydroxytryptamine) lesions. After the placement of either type of lesion, wheel running activity was significantly decreased for the duration of the 8 week post-operative period. Although there were transient decreases in both food and water intakes after damage to the median raphe nucleus, these decreases did not appear to result from impairments in neuro-regulatory mechanisms. Rather, the decrease in food intake seemed to be related to the decrease in locomotor activity, and the decrease in water intake appeared to be linked to the decrease in food intake. In some rats with electrolytic lesions in the median raphe nucleus, the decrease in water intake was followed by a transient period of hyperdipsia.

  16. Phenomenological features of two-proton virtual decay of the 45Fe nucleus

    Science.gov (United States)

    Kadmensky, S. G.; Ivankov, Yu. V.; Lyubashevsky, D. E.

    2017-09-01

    On the basis of the theory of diagonal two-proton two-step virtual decays of spherical nuclei that was developed earlier and the superfluid model of the nucleus, the total and partial widths for the two-proton decay of the 45Fe parent nucleus in the ground state to the ground state of the 43Cr daughter nucleus were calculated along with the angular distribution of protons emitted in this decay. The calculated features of this mode of 45Fe decay were shown to be highly sensitive to the choice of form for nucleon shell potentials. It is also shown that there exists a potential such with which one can construct a successful simultaneous description of the experimental total width and the angular distribution of emitted protons for the aforementioned two-proton mode of decay of the 45Fe nucleus.

  17. Projection and synaptic connectivity of trigeminal mesencephalic nucleus neurons controlling jaw reflexes

    National Research Council Canada - National Science Library

    Yoshida, Atsushi; Moritani, Masayuki; Nagase, Yoshitaka; Bae, Yong Chul

    2017-01-01

    Neurons in the trigeminal mesencephalic nucleus (Vmes) receive deep sensation (proprioception) from jaw-closing muscle spindles and periodontal ligaments and project primarily to the jaw-closing motoneuron pool...

  18. The Arcuate Nucleus: A Site of Fast Negative Feedback for Corticosterone Secretion in Male Rats

    NARCIS (Netherlands)

    Leon-Mercado, Luis; Herrera Moro Chao, Daniela; Basualdo, María Del Carmen; Kawata, Mitsuhiro; Escobar, Carolina; Buijs, Ruud M.

    2017-01-01

    Variations in circulating corticosterone (Cort) are driven by the paraventricular nucleus of the hypothalamus (PVN), mainly via the sympathetic autonomic nervous system (ANS) directly stimulating Cort release from the adrenal gland and via corticotropin-releasing hormone targeting the

  19. Efferent connections of the anterior hypothalamic nucleus: a biocytin study in the cat.

    Science.gov (United States)

    Kanemaru, H; Nakamura, H; Isayama, H; Kawabuchi, M; Tashiro, N

    2000-02-01

    The efferent connections of the anterior hypothalamic nucleus (AH) were examined using biocytin as anterograde tracer in the cat. The results provide several new findings in addition to confirming earlier observations. In the hypothalamus, the AH projections terminated mainly in the medial regions which are related to the defensive, reproductive and feeding behaviors, and autonomic functions. Moreover, we found dense patches of the AH terminals in the medial preoptic area and ventromedial hypothalamic nucleus, which suggests the existence of modular connections between sub-regions of each nucleus. In addition, the AH projected to regions which may be related to the emotional and autonomic responses, i.e., such regions in the amygdala, midline thalamus, septum, subthalamus, and midbrain. The data suggest that the AH may play an important role in the autonomic functions and behaviors between animals, and thus may play a key role in the defensive behavior elicited in the medial preoptic area and ventromedial hypothalamic nucleus.

  20. 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 ...