Shape coexistence and evolution in 98Sr

NASA Astrophysics Data System (ADS)

Park, J.; Garnsworthy, A. B.; Krücken, R.; Andreoiu, C.; Ball, G. C.; Bender, P. C.; Chester, A.; Close, A.; Finlay, P.; Garrett, P. E.; Glister, J.; Hackman, G.; Hadinia, B.; Leach, K. G.; Rand, E. T.; Sjue, S.; Starosta, K.; Svensson, C. E.; Tardiff, E.

2016-01-01

Shape coexistence between the strongly deformed ground state and the weakly deformed 02+ state in 98Sr has been a major topic of interest due to the energy difference of 215 keV, which is the smallest in all even-even nuclei. The electric monopole transition strength ρ2(E 0 ) is an important quantity that can relate the deformation difference and the shape mixing between the two 0+ states, which are admixtures of the vibrational (S) and the rotational (D) states in a simple mixing model. In a β -decay spectroscopy experiment, the experimental ρ2(E 0 ) was measured. A value of 0.053(5) is consistent with the previous measurement and was combined with known electric quadrupole transition strengths B (E 2 ) in calculations of a two-state mixing model. Based on a systematic study on neighboring Kr, Zr, and Mo isotopes, the mixing of the 0+ and 2+ states in 98Sr was determined to be 8.6% and 1.3%, respectively, corresponding to deformation parameters βD=0.38 (1 ) and βS=-0.23 (2 ) . These parameters reproduce experimental transition strengths well except for the 41+→21+ transition, which suggests a smaller D-band deformation for J ≥4 .

Effect of deformations on the compactness of odd-Z superheavy nuclei formed in cold and hot fusion reactions

NASA Astrophysics Data System (ADS)

Kaur, Gurjit; Sandhu, Kirandeep; Sharma, Manoj K.

2018-03-01

Using the extended fragmentation theory, the compactness of hot and cold fusion reactions is analyzed for odd-Z nuclei ranging Z = 105- 117. The calculations for the present work are carried out at T = 0MeV and ℓ = 0 ħ, as the temperature and angular momentum effects remain silent while addressing the orientation degree of freedom (i.e. compact angle configuration). In the hot fusion, 48Ca (spherical) + actinide (prolate) reaction, the non-equatorial compact (nec) shape is obtained for Z = 113 nucleus. On the other hand, Z > 113 nuclei favor equatorial compact (ec) configuration. The distribution of barrier height (VB) illustrate that the ec-shape is obtained when the magnitude of quadrupole deformation of the nucleus is higher than the hexadecupole deformation. In other words, negligible or small -ve β4-deformations support ec configurations. On the other hand, large (+ve) magnitude of the β4-deformation suggests that the configuration appears for compact angle θc < 90 °, leading to nec structure. Similar deformation effects are observed for Bi-induced reactions, in which not belly-to-belly compact (nbbc) configurations are seen at θc = 42 °. In addition to the effect of β2 and β4-deformations, the exclusive role of octupole deformations (β3) is also analyzed. The β3-deformations do not follow the reflection symmetry as that of β2 and β4, leading to the possible occurrence of compact configuration within 0° to 180° angular range.

Spin-dependent γ softness or triaxiality in even-even 132-138Nd nuclei

NASA Astrophysics Data System (ADS)

Chai, Qing-Zhen; Wang, Hua-Lei; Yang, Qiong; Liu, Min-Liang

2015-02-01

The properties of γ instability in rapidly rotating even-even 132-138Nd isotopes have been investigated using the pairing-deformation self-consistent total-Routhian-surface calculations in a deformation space of (β2, γ, β4). It is found that even-even 134-138Nd nuclei exhibit triaxiality in both ground and excited states, even up to high-spin states. The lightest isotope possesses a well-deformed prolate shape without a γ deformation component. The current numerical results are compared with previous calculations and available observables such as quadrupole deformation β2 and the feature of γ-band levels, showing basically a general agreement with the observed trend of γ correlations (e.g. the pattern of the odd-even energy staggering of the γ band). The existing differences between theory and experiment are analyzed and discussed briefly. Supported by National Natural Science Foundation of China (10805040,11175217), Foundation and Advanced Technology Research Program of Henan Province(132300410125) and S & T Research Key Program of Henan Province Education Department (13A140667)

Recoil- α -fission and recoil- α – α -fission events observed in the reaction 48 Ca + 243 Am

DOE PAGES

Forsberg, U.; Rudolph, D.; Andersson, L. -L.; ...

2016-04-26

A recent high-resolution α, X-ray, and γ-ray coincidence-spectroscopy experiment at GSI offered the first glimpse of excitation schemes of isotopes along α-decay chains of Z=115. To understand these observations and to make predictions about shell structure of superheavy nuclei below 288115, we employed nuclear DFT. We find that the presence and nature of low-energy E1 transitions in well-deformed nuclei around Z=110, N=168 strongly depends on the strength of the spin-orbit coupling; hence, it provides an excellent constraint on theoretical models of superheavy nuclei.

Parameterization of deformed nuclei for Glauber modeling in relativistic heavy ion collisions

DOE PAGES

Sorensen, P.; Tang, A. H.; Videbaek, F.; ...

2015-08-04

In this study, the density distributions of large nuclei are typically modeled with a Woods–Saxon distribution characterized by a radius R 0 and skin depth a. Deformation parameters β are then introduced to describe non-spherical nuclei using an expansion in spherical harmonics R 0(1+β 2Y 2 0+β 4Y 4 0). But when a nucleus is non-spherical, the R 0 and a inferred from electron scattering experiments that integrate over all nuclear orientations cannot be used directly as the parameters in the Woods–Saxon distribution. In addition, the β 2 values typically derived from the reduced electric quadrupole transition probability B(E2)↑ aremore » not directly related to the β 2 values used in the spherical harmonic expansion. B(E2)↑ is more accurately related to the intrinsic quadrupole moment Q 0 than to β 2. One can however calculate Q 0 for a given β 2 and then derive B(E2)↑ from Q 0. In this paper we calculate and tabulate the R 0, a , and β 2 values that when used in a Woods–Saxon distribution, will give results consistent with electron scattering data. We then present calculations of the second and third harmonic participant eccentricity (ε 2 and ε 3) with the new and old parameters. We demonstrate that ε 3 is particularly sensitive to a and argue that using the incorrect value of a has important implications for the extraction of viscosity to entropy ratio (η/s) from the QGP created in Heavy Ion collisions.« less

Deformation of nuclei as a function of angular momentum in the U(6) ⊃ SU(3) model

NASA Astrophysics Data System (ADS)

Partensky, A.; Quesne, C.

1981-10-01

In the framework of a hybrid rotational model, proposed recently by Moshinsky as a consequence of a comparison between the Gneuss and Greiner extension of the Bohr and Mottelson model and the interacting boson model, we study the shape of nuclei by calculating the average of the expectation value of the square of the deformation parameter β with respect to the rotational states with the same angular momentum belonging to a given irreducible representation of SU(3). This work generalises to three dimensions the corresponding analysis carried out in two dimensions by Chacón, Moshinsky, and Vanagas. We use the canonical chain for U(3), i.e., the chain U(6) ⊃ U(3) ⊃ U(2) ⊃ U(1), to obtain an analytical formula for the quantity studied. We bring out the overall stretching effect of the angular momentum on the shape of nuclei. The influence of other parameters, such as the boson number and the irreducible representation of SU(3), is also studied.

Skyrme random-phase-approximation description of lowest Kπ=2γ+ states in axially deformed nuclei

NASA Astrophysics Data System (ADS)

Nesterenko, V. O.; Kartavenko, V. G.; Kleinig, W.; Kvasil, J.; Repko, A.; Jolos, R. V.; Reinhard, P.-G.

2016-03-01

The lowest quadrupole γ -vibrational Kπ=2+ states in axially deformed rare-earth (Nd, Sm, Gd, Dy, Er, Yb, Hf, W) and actinide (U) nuclei are systematically investigated within the separable random-phase-approximation (SRPA) based on the Skyrme functional. The energies Eγ and reduced transition probabilities B (E 2 ) of 2γ+ states are calculated with the Skyrme forces SV-bas and SkM*. The energies of two-quasiparticle configurations forming the SRPA basis are corrected by using the pairing blocking effect. This results in a systematic downshift of Eγ by 0.3-0.5 MeV and thus in a better agreement with the experiment, especially in Sm, Gd, Dy, Hf, and W regions. For other isotopic chains, a noticeable overestimation of Eγ and too weak collectivity of 2γ+ states still persist. It is shown that domains of nuclei with low and high 2γ+ collectivity are related to the structure of the lowest two-quasiparticle states and conservation of the Nilsson selection rules. The description of 2γ+ states with SV-bas and SkM* is similar in light rare-earth nuclei but deviates in heavier nuclei. However SV-bas much better reproduces the quadrupole deformation and energy of the isoscalar giant quadrupole resonance. The accuracy of SRPA is justified by comparison with exact RPA. The calculations suggest that a further development of the self-consistent calculation schemes is needed for a systematic satisfactory description of the 2γ+ states.

Study of phase transition of even and odd nuclei based on q-deforme SU(1,1) algebraic model

NASA Astrophysics Data System (ADS)

Jafarizadeh, M. A.; Amiri, N.; Fouladi, N.; Ghapanvari, M.; Ranjbar, Z.

2018-04-01

The q-deformed Hamiltonian for the SO (6) ↔ U (5) transitional case in s, d interaction boson model (IBM) can be constructed by using affine SUq (1 , 1) Lie algebra in the both IBM-1 and 2 versions and IBFM. In this research paper, we have studied the energy spectra of 120-128Xe isotopes and 123-131Xe isotopes and B(E2) transition probabilities of 120-128Xe isotopes in the shape phase transition region between the spherical and gamma unstable deformed shapes of the theory of quantum deformation. The theoretical results agree with the experimental data fairly well. It is shown that the q-deformed SO (6) ↔ U (5) transitional dynamical symmetry remains after deformation.

Role of higher-multipole deformations and noncoplanarity in the decay of the compound nucleus *220Th within the dynamical cluster-decay model

NASA Astrophysics Data System (ADS)

Hemdeep, Chopra, Sahila; Kaur, Arshdeep; Kaushal, Pooja; Gupta, Raj K.

2018-04-01

Background: The formation and decay of the *220Th compound nucleus (CN) formed via some entrance channels (16O+204Pb,40Ar+180Hf,48Ca+172Yb,82Se+138Ba ) at near barrier energies has been studied within the dynamical cluster-decay model (DCM) [Hemdeep et al. Phys. Rev. C 95, 014609 (2017), 10.1103/PhysRevC.95.044603], for quadrupole deformations (β2 i) and "optimum" orientations (θopt) of the two nuclei or decay fragments lying in the same plane (coplanar nuclei, Φ =0∘ ). Purpose: We aim to investigate the role of higher-multipole deformations, the octupole (β3 i) and hexadecupole (β4 i), and "compact" orientations (θc i) together with the noncoplanarity degree of freedom (Φc) in the noncompound nucleus (nCN) cross section, already observed in the above mentioned study with quadrupole deformations (β2 i) alone, the Φ =0∘ case. Methods: The dynamical cluster-decay model (DCM), based on the quantum mechanical fragmentation theory (QMFT), is used to analyze the decay channel cross sections σx n for various experimentally studied entrance channels. The parameter Ra (equivalently, the neck length Δ R in Ra=R1+R2+Δ R ), which fixes both the preformation and penetration paths, is used to best fit both unobserved (1 n ,2 n ) and observed (3 n -5 n ) decay channel cross sections, keeping the root-mean-square (r.m.s) deviation to the minimum, which allows us to predict the nCN effects, if any, and fusion-fission (ff) cross sections in various reactions at different CN excitation energies E*. Results: For the decay of CN *220Th, the mass fragmentation potential V (Ai ) and preformation yields P0( Ai ) show an asymmetric fission mass distribution, in agreement with one observed in experiments, independent of adding or not adding (β3 i,β4 i ), and irrespective of large changes (by 36° and 34°), respectively, in "compact" orientations θc i and noncoplanarity Φc, and also in the potential energy surface V (Ai ) in light mass (1 n -5 n ) decays. Whereas the 3 n - and 5 n -decay channels fit nearly exactly, i.e., they are always the pure CN decays, the 4 n -decay channel shows the presence of large (˜95 % ) nCN content whose magnitude in every case remains the same within <1 % and hence does not get modified, in contrast to our earlier studies of other CN. Also, the near constancy of best fitted Ra(≡Δ R ) with E*, and with an upper limiting value for reactions with magic nuclei as reaction partner(s), independent of the entrance channel nuclei, allows us to predict the decay channel cross sections σx n,x =3 -5 for 16O+204Pb reaction, whose sum (=∑35σx n ) fits the observed σER data nicely. Also, the variations of CN fusion/formation probability PC N and survival probability Psurv follow the required systematic behavior, giving credence to our DCM analysis. Conclusions: With the inclusion of higher-multipole deformations and "compact" noncoplanarity degree of freedom (Φc≠0 ), the results of our above-mentioned earlier study, using quadrupole deformation (β2 i) alone for coplanar (Φc=0 ) nuclei, remain the same; i.e., of the measured 3 n -5 n decay channels of CN *220Th, the 3 n and 5 n decays are always pure CN decays and the 4 n decay is mainly of nCN content σn CN, whose magnitude also remains constant (within <1 % ) under all approximations. Furthermore, the upper limiting value of the linear dependence of first turning point Ra on E* is shown to be a better choice for predicting the decay channel cross sections σx n for reactions like 16O+204Pb using magic nuclei, whose experimental determination will be a good test of our model.

Deformed shell model results for neutrinoless double beta decay of nuclei in A = 60 - 90 region

NASA Astrophysics Data System (ADS)

Sahu, R.; Kota, V. K. B.

2015-03-01

Nuclear transition matrix elements (NTME) for the neutrinoless double beta decay (Oνββ or OνDBD) of 70Zn, 80Se and 82Se nuclei are calculated within the framework of the deformed shell model (DSM) based on Hartree-Fock (HF) states. For 70Zn, jj44b interaction in 2p3/2, 1f5/2, 2p1/2 and 1g9/2 space with 56Ni as the core is employed. However, for 80Se and 82Se nuclei, a modified Kuo interaction with the above core and model space are employed. Most of our calculations in this region were performed with this effective interaction. However, jj44b interaction has been found to be better for 70Zn. The above model space was used in many recent shell model (SM) and interacting boson model (IBM) calculations for nuclei in this region. After ensuring that DSM gives good description of the spectroscopic properties of low-lying levels in these three nuclei considered, the NTME are calculated. The deduced half-lives with these NTME, assuming neutrino mass is 1 eV, are 1.1 × 1026, 2.3 × 1027 and 2.2 × 1024 yr for 70Zn, 80Se and 82Se, respectively.

Quadrupole deformation ({beta},{gamma}) of light {Lambda} hypernuclei in a constrained relativistic mean field model: Shape evolution and shape polarization effect of the {Lambda} hyperon

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lu Bingnan; Zhao Enguang; Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Accelerator, Lanzhou 730000

2011-07-15

The shapes of light normal nuclei and {Lambda} hypernuclei are investigated in the ({beta},{gamma}) deformation plane by using a newly developed constrained relativistic mean field (RMF) model. As examples, the results of some C, Mg, and Si nuclei are presented and discussed in details. We found that for normal nuclei the present RMF calculations and previous Skyrme-Hartree-Fock models predict similar trends of the shape evolution with the neutron number increasing. But some quantitative aspects from these two approaches, such as the depth of the minimum and the softness in the {gamma} direction, differ a lot for several nuclei. For {Lambda}more » hypernuclei, in most cases, the addition of a {Lambda} hyperon alters slightly the location of the ground state minimum toward the direction of smaller {beta} and softer {gamma} in the potential energy surface E{approx}({beta},{gamma}). There are three exceptions, namely, {sub {Lambda}}{sup 13}C, {sub {Lambda}}{sup 23}C, and {sub {Lambda}}{sup 31}Si in which the polarization effect of the additional {Lambda} is so strong that the shapes of these three hypernuclei are drastically different from their corresponding core nuclei.« less

Similarity-transformed dyson mapping and SDG-interacting boson hamiltonian

NASA Astrophysics Data System (ADS)

Navrátil, P.; Dobeš, J.

1991-10-01

The sdg-interacting boson hamiltonian is constructed from the fermion shell-model input. The seniority boson mapping as given by the similarity-transformed Dyson boson mapping is used. The s, d, and g collective boson amplitudes are determined consistently from the mapped hamiltonian. Influence of the starting shell-model parameters is discussed. Calculations for the Sm isotopic chain and for the 148Sm, 150Nd, and 196Pt nuclei are presented. Calculated energy levels as well as E2 and E4 properties agree rather well with experimental ones. To obtain such agreement, the input shell-model parameters cannot be fixed at a constant set for several nuclei but have to be somewhat varied, especially in the deformed region. Possible reasons for this variation are discussed. Effects of the explicit g-boson consideration are shown.

Collectivity of light Ge and As isotopes

NASA Astrophysics Data System (ADS)

Corsi, A.; Delaroche, J.-P.; Obertelli, A.; Baugher, T.; Bazin, D.; Boissinot, S.; Flavigny, F.; Gade, A.; Girod, M.; Glasmacher, T.; Grinyer, G. F.; Korten, W.; Libert, J.; Ljungvall, J.; McDaniel, S.; Ratkiewicz, A.; Signoracci, A.; Stroberg, R.; Sulignano, B.; Weisshaar, D.

2013-10-01

Background: The self-conjugate nuclei of the A˜70 mass region display rapid shape evolution over isotopic or isotonic chains. Shape coexistence has been observed in Se and Kr isotopes reflecting the existence of deformed subshell gaps corresponding to different shell configurations. As and Ge isotopes are located halfway between such deformed nuclei and the Z=28 shell closure.Purpose: The present work aims at clarifying the low-lying spectroscopy of 66Ge and 67As, and providing a better insight into the evolution of collectivity in light even-even Ge and even-odd As isotopes.Methods: We investigate the low-lying levels and collectivity of the neutron deficient 67As and 66Ge through intermediate-energy Coulomb excitation, inelastic scattering, and proton knockout measurements. The experiment was performed using a cocktail beam of 68Se, 67As, and 66Ge nuclei at an energy of 70-80 MeV/nucleon. Spectroscopic properties of the low-lying states are compared to those calculated via shell model with the JUN45 interaction and beyond-mean-field calculations with the five-dimensional collective Hamiltonian method implemented using the Gogny D1S interaction. The structure evolution of the lower-mass Ge and As isotopes is discussed.Results: Reduced electric quadrupole transition probabilities B(E2) have been extracted from the Coulomb-excitation cross sections measured in 66Ge and 67As. The value obtained for the B(E2;01+→21+) in 66Ge is in agreement with a recent measurement, ruling out the existence of a minimum at N=34 in the B(E2) systematics as previously observed. New transitions have been found in 67As and were assigned to the decay of low-lying negative-parity states.

The structure of nuclei far from stability. [Dept. of Physics and Astronomy, Louisiana State Univ. , Baton Rouge, Louisiana

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zganjar, E.F.

1993-01-01

Studies on nuclei near Z=82 contributed to the establishment of a new region of nuclear deformation and a new class of nuclear structure at closed shells. A important aspect of this work is the establishment of the connection between low-lying 0[sup +] states in even[endash]even nuclei and the occurrence of shape coexistence in the odd-mass neighbors (E0 transitions in [sup 185]Pt, shape coexistence in [sup 184]Pt and [sup 187]Au). A new type of picosecond lifetime measurement system capable of measuring the lifetime of states that decay only by internal conversion was developed and applied to the [sup 186,188]Tl decay tomore » determine the lifetime of the 0[sub 2][sup +] and 2[sub 2][sup +] deformed states in [sup 186,188]Hg. A search for the population of superdeformed states in [sup 192]Hg by the radioactive decay of [sup 192]Tl was accomplished by using a prototype internal pair formation spectrometer.« less

Deformation of nuclei as a function of angular momentum in the U(6)containsSU(3) model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Partensky, A.

1981-10-15

In the framework of a hybrid rotational model, proposed recently by Moshinsky as a consequence of a comparison between the Gneuss and Greiner extension of the Bohr and Mottelson model and the interacting boson model, we study the shape of nuclei by calculating the average of the expectation value of the square of the deformation parameter ..beta.. with respect to the rotational states with the same angular momentum belonging to a given irreducible representation of SU(3). This work generalises to three dimensions the corresponding analysis carried out in two dimensions by Chacon, Moshinsky, and Vanagas. We use the canonical chainmore » for U(3), i.e.,the chain U(6)containsU(3)containsU(2)containsU(1), to obtain an analytical formula for the quantity studied. We bring out the overall stretching effect of the angular momentum on the shape of nuclei. The influence of other parameters, such as the boson number and the irreducible representation of SU(3), is also studied.« less

Direct evidence of octupole deformation in neutron-rich 144Ba

DOE PAGES

Bucher, B.; Zhu, S.; Wu, C. Y.; ...

2016-03-17

Here, the neutron-rich nucleus 144Ba (t 1/2 = 11.5 s) is expected to exhibit some of the strongest octupole correlations among nuclei with mass numbers A less than 200. Until now, indirect evidence for such strong correlations has been inferred from observations such as enhanced E1 transitions and interleaving positive- and negative-parity levels in the ground-state band. In this experiment, the octupole strength was measured directly by sub-barrier, multistep Coulomb excitation of a post-accelerated 650-MeV 144Ba beam on a 1.0–mg/cm 2 208Pb target. The measured value of the matrix element, < 3 1–∥M(E3)∥0 1 + >= 0.65( +17 –23) ebmore » 3/2, corresponds to a reduced B(E3) transition probability of 48( +25 –34) W.u. This result represents an unambiguous determination of the octupole collectivity, is larger than any available theoretical prediction, and is consistent with octupole deformation.« less

Density of high-spin states in38Ar and42Ca

NASA Astrophysics Data System (ADS)

Kern, Th.; Betz, P.; Bitterwolf, E.; Glatz, F.; Röpke, H.

1980-03-01

The γ-decay modes of38Ar levels with E x ≦11,630keV and of42Ca levels with E x ≦10,036keV have been studied using the35Cl( α, pγ) reaction at 16MeV and the39K( α, pγ) reaction at 15.14 MeV, respectively. In both nuclei the number of states with J≧6 exceeds fifty. Weak coupling calculations of the Bansal and French type reproduce the density of high-spin states. The success of the model implies that the excitations of up to four particles from the d 3/2 into the f 7/2 shell play a role in both nuclei. The structure of deformed states was found to be predominantly 4 p/s 6 h in38Ar and 4 p/s 2 h in42Ca, respectively.

Parity doublet structures in doubly-odd 216Fr

NASA Astrophysics Data System (ADS)

Pragati, Â.; Deo, A. Y.; Tandel, S. K.; Bhattacharjee, S. S.; Chakraborty, S.; Rai, S.; Wahid, S. G.; Kumar, S.; Muralithar, S.; Singh, R. P.; Bala, Indu; Garg, Ritika; Jain, A. K.

2018-04-01

Parity doublet structures are established in 216Fr, which lies at the lower boundary of enhanced octupole collectivity in the trans-lead region. The newly identified levels are established as the simplex partner of a previously reported band leading to parity doublets with small (˜55 keV) average energy splitting, a feature typical of nuclei with near-static octupole deformation. The observed levels do not follow a regular pattern of rotational bands, indicating low quadrupole collectivity. However, enhanced octupole correlations are evident from the small energy splitting and large B(E1)/B(E2) values. Staggering in E1 transition energies and B(E1)/B(E2) ratios is noted. The enhancement of octupole correlations in 216Fr is attributed to the availability of a neutron orbital with a K = 3/2 component.

Superdeformed shapes and configurations in thallium nuclei

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reviol, W.; Mueller, W.F.; Riedinger, L.L.

1997-09-01

Superdeformation studies in {sup 189,191,192}Tl at Gammasphere are discussed. New results on {sup 191}Tl are the observation of interband transitions between the signature partner E2 bands and the measurement of an average quadrupole moment (Q{sub 0} = 18 {+-} 1 eb) for these superdeformed structures. These data enable them to derive absolute M1 strengths and confirm that the 81st proton occupies the [642]5/2 orbital. Tentative data for one superdeformed sequence in {sup 189}Tl are consistent with the prediction of a decrease in quadrupole deformation for the lightest nuclei at the limit of this island of superdeformation.

Deformed shell model results for neutrinoless positron double beta decay of nuclei in the A = 60-90 region

NASA Astrophysics Data System (ADS)

Sahu, R.; Srivastava, P. C.; Kota, V. K. B.

2013-09-01

Nuclear transition matrix elements (NTME) for neutrinoless positron double beta decay (0νβ+β+ and 0νβ+EC) of 64Zn, 74Se, 78Kr and 84Sr nuclei, which are in the A = 60-90 region, are calculated within the framework of the deformed shell model (DSM) based on Hartree-Fock states. For 64Zn, GXPF1A interaction in 1f7/2, 2p3/2, 1f5/2 and 2p1/2 space with 40Ca as the core is employed. Similarly for 74Se, 78Kr and 84Sr nuclei, 56Ni is taken as the inert core employing a modified Kuo interaction in 2p3/2, 1f5/2, 2p1/2 and 1g9/2 space. After ensuring that the DSM gives a good description of the spectroscopic properties of low-lying levels in the four nuclei considered, the NTME are calculated. The half-lives deduced with these NTME, assuming the neutrino mass is 1 eV, are smallest for 78Kr with the half-life for β+EC decay being ˜1027 yr. For all others, the half-lives are in the range of ˜1028-1029 yr.

Large-scale deformed quasiparticle random-phase approximation calculations of the γ -ray strength function using the Gogny force

NASA Astrophysics Data System (ADS)

Martini, M.; Péru, S.; Hilaire, S.; Goriely, S.; Lechaftois, F.

2016-07-01

Valuable theoretical predictions of nuclear dipole excitations in the whole chart are of great interest for different nuclear applications, including in particular nuclear astrophysics. Here we present large-scale calculations of the E 1 γ -ray strength function obtained in the framework of the axially symmetric deformed quasiparticle random-phase approximation based on the finite-range Gogny force. This approach is applied to even-even nuclei, the strength function for odd nuclei being derived by interpolation. The convergence with respect to the adopted number of harmonic oscillator shells and the cutoff energy introduced in the 2-quasiparticle (2 -q p ) excitation space is analyzed. The calculations performed with two different Gogny interactions, namely D1S and D1M, are compared. A systematic energy shift of the E 1 strength is found for D1M relative to D1S, leading to a lower energy centroid and a smaller energy-weighted sum rule for D1M. When comparing with experimental photoabsorption data, the Gogny-QRPA predictions are found to overestimate the giant dipole energy by typically ˜2 MeV. Despite the microscopic nature of our self-consistent Hartree-Fock-Bogoliubov plus QRPA calculation, some phenomenological corrections need to be included to take into account the effects beyond the standard 2 -q p QRPA excitations and the coupling between the single-particle and low-lying collective phonon degrees of freedom. For this purpose, three prescriptions of folding procedure are considered and adjusted to reproduce experimental photoabsorption data at best. All of them are shown to lead to somewhat similar predictions of the E 1 strength, both at low energies and for exotic neutron-rich nuclei. Predictions of γ -ray strength functions and Maxwellian-averaged neutron capture rates for the whole Sn isotopic chain are also discussed and compared with previous theoretical calculations.

Influence of sticking vs non-sticking limits of moment of inertia and higher order deformations in the decay of 214,216Rn* compound systems

NASA Astrophysics Data System (ADS)

Mittal, Rajni; Jain, Deepika; Sharma, Manoj K.

2017-12-01

The dynamical cluster decay model (DCM) is employed to explore the relative effect of sticking (IS) and non-sticking (INS) limits of moment of inertia (MOI) in the decay of hot and rotating 214,216Rn* compound nuclei, formed in 16,18O + 198Pt reactions. Beside this, the nuclear deformation effects i.e. quadrupole β2 (static and dynamic) and higher order static deformations up to hexadecapole (β4) are duly incorporated and studied within DCM. The influence of both 'INS/IS' addressing rotational energy component and 'deformations' is gauged through the barrier characteristics, preformation factor and barrier lowering effects. The experimentally given ER and ff data is addressed by optimizing the neck-length ΔR, that strongly depends on the limiting angular momentum, which in turn depends on the sticking or non-sticking limits of interaction. In addition to this, the influence of increase in energy and neutron number is probed in reference to ER survival probability of Rn compound nucleus. Finally, the ff cross-sections of 214,216Rn* nuclei are predicted within sticking limit of moment of inertia as the same seems to be more suitable for such decay paths.

Reflection Asymmetric Shapes in the Neutron-Rich 140,143Ba Isotopes

NASA Astrophysics Data System (ADS)

Zhu Sheng-jiang (S, J. Zhu; Wang, Mu-ge; J, H. Hamilton; A, V. Ramayya; B, R. S. Babu; W, C. Ma; Long, Gui-lu; Deng, Jing-kang; Zhu, Ling-yan; Li, Ming; T, N. Ginter; J, Komicki; J, D. Cole; R, Aryaeinejad; Y, K. Dardenne; M, W. Drigert; J, O. Rasmussen; Ts, Yu Oganessian; M, A. Stoyer; S, Y. Chu; K, E. Gregorich; M, F. Mohar; S, G. Prussin; I, Y. Lee; N, R. Johnson; F, K. McGowan

1997-08-01

Level schemes for the neutron-rich 140,143Ba nuclei have been determined by study of prompt γ-rays in spontaneous fission of 252Cf. The level pattern and enhanced E1 transitions between π = + and π = - bands show reflection asymmetric shapes with simplex quantum number s = +1 in 140Ba and s = ±i in 143Ba, respectively. The octupole deformation stability with spin variation has been discussed.

Deformation effect on spectral statistics of nuclei

NASA Astrophysics Data System (ADS)

Sabri, H.; Jalili Majarshin, A.

2018-02-01

In this study, we tried to get significant relations between the spectral statistics of atomic nuclei and their different degrees of deformations. To this aim, the empirical energy levels of 109 even-even nuclei in the 22 ≤ A ≤ 196 mass region are classified as their experimental and calculated quadrupole, octupole, hexadecapole and hexacontatetrapole deformations values and analyzed by random matrix theory. Our results show an obvious relation between the regularity of nuclei and strong quadrupole, hexadecapole and hexacontatetrapole deformations and but for nuclei that their octupole deformations are nonzero, we have observed a GOE-like statistics.

Octupole deformation in neutron-rich actinides and superheavy nuclei and the role of nodal structure of single-particle wavefunctions in extremely deformed structures of light nuclei

NASA Astrophysics Data System (ADS)

Afanasjev, A. V.; Abusara, H.; Agbemava, S. E.

2018-03-01

Octupole deformed shapes in neutron-rich actinides and superheavy nuclei as well as extremely deformed shapes of the N∼ Z light nuclei have been investigated within the framework of covariant density functional theory. We confirmed the presence of new region of octupole deformation in neutron-rich actinides with the center around Z∼ 96,N∼ 196 but our calculations do not predict octupole deformation in the ground states of superheavy Z≥slant 108 nuclei. As exemplified by the study of 36Ar, the nodal structure of the wavefunction of occupied single-particle orbitals in extremely deformed structures allows to understand the formation of the α-clusters in very light nuclei, the suppression of the α-clusterization with the increase of mass number, the formation of ellipsoidal mean-field type structures and nuclear molecules.

Calculation of multidimensional potential energy surfaces for even-even transuranium nuclei: systematic investigation of the triaxiality effect on the fission barrier

NASA Astrophysics Data System (ADS)

Chai, Qing-Zhen; Zhao, Wei-Juan; Liu, Min-Liang; Wang, Hua-Lei

2018-05-01

Static fission barriers for 95 even-even transuranium nuclei with charge number Z = 94–118 have been systematically investigated by means of pairing self-consistent Woods-Saxon-Strutinsky calculations using the potential energy surface approach in multidimensional (β 2, γ, β 4) deformation space. Taking the heavier 252Cf nucleus (with the available fission barrier from experiment) as an example, the formation of the fission barrier and the influence of macroscopic, shell and pairing correction energies on it are analyzed. The results of the present calculated β 2 values and barrier heights are compared with previous calculations and available experiments. The role of triaxiality in the region of the first saddle is discussed. It is found that the second fission barrier is also considerably affected by the triaxial deformation degree of freedom in some nuclei (e.g., the Z=112–118 isotopes). Based on the potential energy curves, general trends of the evolution of the fission barrier heights and widths as a function of the nucleon numbers are investigated. In addition, the effects of Woods-Saxon potential parameter modifications (e.g., the strength of the spin-orbit coupling and the nuclear surface diffuseness) on the fission barrier are briefly discussed. Supported by National Natural Science Foundation of China (11675148, 11505157), the Project of Youth Backbone Teachers of Colleges and Universities of Henan Province (2017GGJS008), the Foundation and Advanced Technology Research Program of Henan Province (162300410222), the Outstanding Young Talent Research Fund of Zhengzhou University (1521317002) and the Physics Research and Development Program of Zhengzhou University (32410017)

Electric Quadrupole E2- Transitions of 170-174 Yb Isotopes

NASA Astrophysics Data System (ADS)

Abu El Sheikh, Mohd Kh. M.; Okhunov, Abdurahim A.; Usmanov, Ph. N.; Hassan, Torla HJ

2017-12-01

The non-adiabatic effects which is manifested in the electric properties of low-lying states of even-even deformed nuclei are studied. A simple phenomenological model which takes into account the Coriolis mixing of {K}π ={0}n+,{2}n+ and {K}π ={1}ν + state bands. The Calculations for isotopes 170-174 Yb, are carried out. The reduced probability of electric quadrupole transitions from the states {0}ν + and {2}ν + - bands to the ground (gr) state band is calculated and non adiabatic effect is discussed. The ratio of E2- transitions RIK from {0}2+, {0}3+, {2}1+, and {2}2+ bands are calculated and compared with the experimental data.

Individual Low-Energy Toroidal Dipole State in Mg 24

NASA Astrophysics Data System (ADS)

Nesterenko, V. O.; Repko, A.; Kvasil, J.; Reinhard, P.-G.

2018-05-01

The low-energy dipole excitations in Mg 24 are investigated within the Skyrme quasiparticle random phase approximation for axial nuclei. The calculations with the force SLy6 reveal a remarkable feature: the lowest IπK =1-1 excitation (E =7.92 MeV ) in Mg 24 is a vortical toroidal state (TS) representing a specific vortex-antivortex realization of the well-known spherical Hill's vortex in a strongly deformed axial confinement. This is a striking example of an individual TS which can be much more easily discriminated in experiment than the toroidal dipole resonance embracing many states. The TS acquires the lowest energy due to the huge prolate axial deformation in Mg 24 . The result persists for different Skyrme parametrizations (SLy6, SVbas, SkM*). We analyze spectroscopic properties of the TS and its relation with the cluster structure of Mg 24 . Similar TSs could exist in other highly prolate light nuclei. They could serve as promising tests for various reactions to probe a vortical (toroidal) nuclear flow.

Experimental study of the electric dipole strength in the even Mo nuclei and its deformation dependence

NASA Astrophysics Data System (ADS)

Erhard, M.; Junghans, A. R.; Nair, C.; Schwengner, R.; Beyer, R.; Klug, J.; Kosev, K.; Wagner, A.; Grosse, E.

2010-03-01

Two methods based on bremsstrahlung were applied to the stable even Mo isotopes for the experimental determination of the photon strength function covering the high excitation energy range above 4 MeV with its increasing level density. Photon scattering was used up to the neutron separation energies Sn and data up to the maximum of the isovector giant resonance (GDR) were obtained by photoactivation. After a proper correction for multistep processes the observed quasicontinuous spectra of scattered photons show a remarkably good match to the photon strengths derived from nuclear photoeffect data obtained previously by neutron detection and corrected in absolute scale by using the new activation results. The combined data form an excellent basis to derive a shape dependence of the E1 strength in the even Mo isotopes with increasing deviation from the N=50 neutron shell (i.e., with the impact of quadrupole deformation and triaxiality). The wide energy coverage of the data allows for a stringent assessment of the dipole sum rule and a test of a novel parametrization developed previously which is based on it. This parametrization for the electric dipole strength function in nuclei with A>80 deviates significantly from prescriptions generally used previously. In astrophysical network calculations it may help to quantify the role the p-process plays in cosmic nucleosynthesis. It also has impact on the accurate analysis of neutron capture data of importance for future nuclear energy systems and waste transmutation.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sukhovoj, A. M., E-mail: suchovoj@nf.jinr.ru; Mitsyna, L. V., E-mail: mitsyna@nf.jinr.ru; Jovancevic, N., E-mail: nikola.jovancevic@uns.ac.rs

The intensities of two-step cascades in 43 nuclei of mass number in the range of 28 ≤ A ≤ 200 were approximated to a high degree of precision within a modified version of the practical cascade-gammadecay model introduced earlier. In this version, the rate of the decrease in the model-dependent density of vibrational levels has the same value for any Cooper pair undergoing breakdown. The most probable values of radiative strength functions both for E1 and for M1 transitions are determined by using one or two peaks against a smooth model dependence on the gamma-transition energy. The statement that themore » thresholds for the breaking of Cooper pairs are higher for spherical than for deformed nuclei is a basic result of the respective analysis. The parameters of the cascade-decay process are now determined to a precision that makes it possible to observe the systematic distinctions between them for nuclei characterized by different parities of neutrons and protons.« less

Collective systematics in the mass 80 region

NASA Astrophysics Data System (ADS)

Tabor, S. L.

1986-07-01

The deformation of nuclei around A~80 is found to vary systematically as a function of the product of the number of protons and neutrons (or holes) (NpNn) in the shell extending from 28 to 50 particles. A similar result was reported previously for heavier even A nuclei, but this is the first investigation of a region in which neutrons and protons fill the same major shell and the first application of the technique to odd A nuclei. The systematic behavior is seen in both energy level spacings and electromagnetic quadrupole transition strengths and in both even-even and odd A nuclei. These systematics hold for the measures of deformation not involving the positions of the 0+ states, which are strongly affected by the coexistence of weakly and strongly deformed shapes in some A~80 nuclei. A rather surprising result is that the deformations of the odd-Z-even-N nuclei are substantially larger than those of the even-Z-odd-N nuclei.

Description of transitional nuclei in the sdg boson model

NASA Astrophysics Data System (ADS)

Lac, V.-S.; Kuyucak, S.

1992-03-01

We study the transitional nuclei in the framework of the sdg boson model. This extension is necessitated by recent measurements of E2 and E4 transitions in the Pt and Os isotopes which can not be explained in the sd boson models. We show how γ-unstable and triaxial shapes arise from special choices of sdg model hamiltonians and discuss ways of limiting the number of free parameters through consistency and coherence conditions. A satisfactory description of E2 and E4 properties is obtained for the Pt and Os nuclei, which also predicts dynamic shape transitions in these nuclei.

Novel solution of power law for γ-bands

NASA Astrophysics Data System (ADS)

Gupta, J. B.

The power law expression E = aIb offers a single-term formula with just two parameters for expressing the level energies in the spectra of even-Z even-N nuclei. Its application to ground band spectra for a wide range of nuclei has been demonstrated in our earlier works. Here, we extend its application to the rotational bands built on an excited state of K = 2 γ-vibration band and Kπ = 0 2+ beta band. A novel assumption of a virtual level with spin zero for γ-bands is made and its validity and use is illustrated. Here, the constancy of the parameters “b” and “a” with spin, offers a more realistic view of the dependence of the nuclear core deformation on spin, in the excited bands. Also, it enables a spinwise view, not available in the other energy fit expressions.

Configuration-constrained cranking Hartree-Fock pairing calculations for sidebands of nuclei

NASA Astrophysics Data System (ADS)

Liang, W. Y.; Jiao, C. F.; Wu, Q.; Fu, X. M.; Xu, F. R.

2015-12-01

Background: Nuclear collective rotations have been successfully described by the cranking Hartree-Fock-Bogoliubov (HFB) model. However, for rotational sidebands which are built on intrinsic excited configurations, it may not be easy to find converged cranking HFB solutions. The nonconservation of the particle number in the BCS pairing is another shortcoming. To improve the pairing treatment, a particle-number-conserving (PNC) pairing method was suggested. But the existing PNC calculations were performed within a phenomenological one-body potential (e.g., Nilsson or Woods-Saxon) in which one has to deal the double-counting problem. Purpose: The present work aims at an improved description of nuclear rotations, particularly for the rotations of excited configurations, i.e., sidebands. Methods: We developed a configuration-constrained cranking Skyrme Hartree-Fock (SHF) calculation with the pairing correlation treated by the PNC method. The PNC pairing takes the philosophy of the shell model which diagonalizes the Hamiltonian in a truncated model space. The cranked deformed SHF basis provides a small but efficient model space for the PNC diagonalization. Results: We have applied the present method to the calculations of collective rotations of hafnium isotopes for both ground-state bands and sidebands, reproducing well experimental observations. The first up-bendings observed in the yrast bands of the hafnium isotopes are reproduced, and the second up-bendings are predicted. Calculations for rotational bands built on broken-pair excited configurations agree well with experimental data. The band-mixing between two Kπ=6+ bands observed in 176Hf and the K purity of the 178Hf rotational state built on the famous 31 yr Kπ=16+ isomer are discussed. Conclusions: The developed configuration-constrained cranking calculation has been proved to be a powerful tool to describe both the yrast bands and sidebands of deformed nuclei. The analyses of rotational moments of inertia help to understand the structures of nuclei, including rotational alignments, configurations, and competitions between collective and single-particle excitations.

Quantum self-organization and nuclear collectivities

NASA Astrophysics Data System (ADS)

Otsuka, T.; Tsunoda, Y.; Togashi, T.; Shimizu, N.; Abe, T.

2018-02-01

The quantum self-organization is introduced as one of the major underlying mechanisms of the quantum many-body systems. In the case of atomic nuclei as an example, two types of the motion of nucleons, single-particle states and collective modes, dominate the structure of the nucleus. The outcome of the collective mode is determined basically by the balance between the effect of the mode-driving force (e.g., quadrupole force for the ellipsoidal deformation) and the resistance power against it. The single-particle energies are one of the sources to produce such resistance power: a coherent collective motion is more hindered by larger gaps between relevant single particle states. Thus, the single-particle state and the collective mode are “enemies” each other. However, the nuclear forces are demonstrated to be rich enough so as to enhance relevant collective mode by reducing the resistance power by changing singleparticle energies for each eigenstate through monopole interactions. This will be verified with the concrete example taken from Zr isotopes. Thus, when the quantum self-organization occurs, single-particle energies can be self-organized, being enhanced by (i) two quantum liquids, e.g., protons and neutrons, (ii) two major force components, e.g., quadrupole interaction (to drive collective mode) and monopole interaction (to control resistance). In other words, atomic nuclei are not necessarily like simple rigid vases containing almost free nucleons, in contrast to the naïve Fermi liquid picture. Type II shell evolution is considered to be a simple visible case involving excitations across a (sub)magic gap. The quantum self-organization becomes more important in heavier nuclei where the number of active orbits and the number of active nucleons are larger. The quantum self-organization is a general phenomenon, and is expected to be found in other quantum systems.

Collectivity in the light radon nuclei measured directly via Coulomb excitation

NASA Astrophysics Data System (ADS)

Gaffney, L. P.; Robinson, A. P.; Jenkins, D. G.; Andreyev, A. N.; Bender, M.; Blazhev, A.; Bree, N.; Bruyneel, B.; Butler, P. A.; Cocolios, T. E.; Davinson, T.; Deacon, A. N.; De Witte, H.; DiJulio, D.; Diriken, J.; Ekström, A.; Fransen, Ch.; Freeman, S. J.; Geibel, K.; Grahn, T.; Hadinia, B.; Hass, M.; Heenen, P.-H.; Hess, H.; Huyse, M.; Jakobsson, U.; Kesteloot, N.; Konki, J.; Kröll, Th.; Kumar, V.; Ivanov, O.; Martin-Haugh, S.; Mücher, D.; Orlandi, R.; Pakarinen, J.; Petts, A.; Peura, P.; Rahkila, P.; Reiter, P.; Scheck, M.; Seidlitz, M.; Singh, K.; Smith, J. F.; Van de Walle, J.; Van Duppen, P.; Voulot, D.; Wadsworth, R.; Warr, N.; Wenander, F.; Wimmer, K.; Wrzosek-Lipska, K.; Zielińska, M.

2015-06-01

Background: Shape coexistence in heavy nuclei poses a strong challenge to state-of-the-art nuclear models, where several competing shape minima are found close to the ground state. A classic region for investigating this phenomenon is in the region around Z =82 and the neutron midshell at N =104 . Purpose: Evidence for shape coexistence has been inferred from α -decay measurements, laser spectroscopy, and in-beam measurements. While the latter allow the pattern of excited states and rotational band structures to be mapped out, a detailed understanding of shape coexistence can only come from measurements of electromagnetic matrix elements. Method: Secondary, radioactive ion beams of 202Rn and 204Rn were studied by means of low-energy Coulomb excitation at the REX-ISOLDE in CERN. Results: The electric-quadrupole (E 2 ) matrix element connecting the ground state and first excited 21+ state was extracted for both 202Rn and 204Rn, corresponding to B (E 2 ;21+→01+) =29-8+8 and 43-12+17 W.u., respectively. Additionally, E 2 matrix elements connecting the 21+ state with the 41+ and 22+ states were determined in 202Rn. No excited 0+ states were observed in the current data set, possibly owing to a limited population of second-order processes at the currently available beam energies. Conclusions: The results are discussed in terms of collectivity and the deformation of both nuclei studied is deduced to be weak, as expected from the low-lying level-energy schemes. Comparisons are also made to state-of-the-art beyond-mean-field model calculations and the magnitude of the transitional quadrupole moments are well reproduced.

Scissors Modes and Spin Excitations in Light Nuclei Including ΔN=2 Excitations: Behaviour of 8Be and 10Be

NASA Astrophysics Data System (ADS)

Fayache, M. S.; Sharma, S. Shelley; Zamick, L.

1996-10-01

Shell model calculations are performed for magnetic dipole excitations in8Be and10Be, first with a quadrupole-quadrupole interaction (Q·Q) and then with a realistic interaction. The calculations are performed both in a 0pspace and in a large space which includes all 2ℏωexcitations. In the 0pwithQ·Qwe have an analytic expression for the energies of all states. In this limit we find that in10Be theL=1S=0 scissors mode with isospinT=1 is degenerate with that ofT=2. By projection from an intrinsic state we can obtain simple expressions forB(M1) to the scissors modes in8Be and10Be. We plot cumulative sums for energy-weighted isovector orbital transitions fromJ=0+ground states to the 1+excited states. These have the structure of a low-energy plateau and a steep rise to a high-energy plateau. The relative magnitudes of these plateaux are discussed. By comparing8Be and10Be we find that contrary to the behaviour in heavy deformed nuclei,B(M1)orbitalis not proportional toB(E2). On the other hand, a sum rule which relatesB(M1) to the difference (B(E2)isoscalar-B(E2)isovector) succeeds in describing the difference in behaviours in the two nuclei. The results forQ·Qand the realistic interactions are compared, as are the results in the 0pspace and the large (0p+2ℏω) space. The Wigner supermultiplet scheme is a very useful guide in analyzing the shell model results.

Study of ^{14}C Cluster Decay Half-Lives of Heavy Deformed Nuclei

NASA Astrophysics Data System (ADS)

Shamami, S. Rahimi; Pahlavani, M. R.

2018-01-01

A theoretical model based on deformed Woods-Saxon, Coulomb and centrifugal terms are constructed to evaluate the half-lives for the cluster radioactivity of various super heavy nuclei. Deformation have been applied on all parts of their potential containing nuclear barrier for cluster decay. Also, both parent and daughter nuclei are considered to be deformed. The calculated results of ^{14}C cluster radioactivity half-lives are compared with available experimental data. A satisfactory agreement between theoretical and measured data is achieved. Also, obtained half-lives for each decay family is agreed with Geiger-Nuttall law.

Skyrme RPA description of γ-vibrational states in rare-earth nuclei

NASA Astrophysics Data System (ADS)

Nesterenko, V. O.; Kartavenko, V. G.; Kleinig, W.; Kvasil, J.; Repko, A.; Jolos, R. V.; Reinhard, P.-G.

2016-01-01

The lowest γ-vibrational states with Kπ = 2+γ in well-deformed Dy, Er and Yb isotopes are investigated within the self-consistent separable quasiparticle random-phase-approximation (QRPA) approach based on the Skyrme functional. The energies Eγ and reduced transition probabilities B(E2)γ of the states are calculated with the Skyrme force SV-mas10. We demonstrate the strong effect of the pairing blocking on the energies of γ-vibrational states. It is also shown that collectivity of γ-vibrational states is strictly determined by keeping the Nilsson selection rules in the corresponding lowest 2qp configurations.

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

NASA Astrophysics Data System (ADS)

Praharaj, Choudhury

2016-03-01

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

Surface symmetry energy of nuclear energy density functionals

NASA Astrophysics Data System (ADS)

Nikolov, N.; Schunck, N.; Nazarewicz, W.; Bender, M.; Pei, J.

2011-03-01

We study the bulk deformation properties of the Skyrme nuclear energy density functionals (EDFs). Following simple arguments based on the leptodermous expansion and liquid drop model, we apply the nuclear density functional theory to assess the role of the surface symmetry energy in nuclei. To this end, we validate the commonly used functional parametrizations against the data on excitation energies of superdeformed band heads in Hg and Pb isotopes and fission isomers in actinide nuclei. After subtracting shell effects, the results of our self-consistent calculations are consistent with macroscopic arguments and indicate that experimental data on strongly deformed configurations in neutron-rich nuclei are essential for optimizing future nuclear EDFs. The resulting survey provides a useful benchmark for further theoretical improvements. Unlike in nuclei close to the stability valley, whose macroscopic deformability hangs on the balance of surface and Coulomb terms, the deformability of neutron-rich nuclei strongly depends on the surface symmetry energy; hence, its proper determination is crucial for the stability of deformed phases of the neutron-rich matter and description of fission rates for r-process nucleosynthesis.

Vibrational and rotational sequences in 101Mo and 103,4Ru studied via multinucleon transfer reactions

DOE PAGES

Regan, P. H.; Wheldon, C.; Yamamoto, A. D.; ...

2005-04-01

The near-yrast states of 42 101Mo 59 and 44 103,4Ru 59,60 have been studied following their population via heavy-ion multinucleon transfer reactions between a 136 Xe beam and a thin, self-supporting 100Mo target. The ground state sequence in 104Ru can be understood as demonstrating a simple evolution from a quasi-vibrational structure at lower spins to statically deformed, quasi-rotational excitation involving the population of a pair of low-Ω h 11/2 neutron orbitals. The effect of the decoupled h 11/2 orbital on this vibration-to-rotational evolution is demonstrated by an extension of the "E-GOS" prescription to include odd-A nuclei. The experimental results aremore » also compared with self-consistent Total Routhian Surface calculations which also highlight the polarising role of the highly aligned neutron h 11/2 orbital in these nuclei.« less

Isomer spectroscopy of neutron-rich $$^{165,167}$$Tb

DOE PAGES

Gurgi, L. A.; Regan, P. H.; Soderstrom, P. -A.; ...

2017-01-01

We present information on the excited states in the prolate-deformed, neutron-rich nuclei 165,167Tb 100,102. The nuclei of interest were synthesised following in-flight fission of a 345 MeV per nucleon 238U primary beam on a 2 mm 9Be target at the Radioactive Ion-Beam Factory (RIBF), RIKEN, Japan. The exotic nuclei were separated and identified event-by-event using the BigRIPS separator, with discrete energy gamma-ray decays from isomeric states with half-lives in the μs regime measured using the EURICA gamma-ray spectrometer. Metastable-state decays are identified in 165Tb and 167Tb and interpreted as arising from hindered E1 decay from the 72 –[523] single quasi-protonmore » Nilsson configuration to rotational states built on the 32 –[411] single quasi-proton ground state. Lastly, these data correspond to the first spectroscopic information in the heaviest, odd-A terbium isotopes reported to date and provide information on proton Nilsson configurations which reside close to the Fermi surface as the 170Dy doubly-midshell nucleus is approached.« less

Shell evolution beyond Z = 28 and N = 50: Spectroscopy of 81,82,83,84Zn

NASA Astrophysics Data System (ADS)

Shand, C. M.; Podolyák, Zs.; Górska, M.; Doornenbal, P.; Obertelli, A.; Nowacki, F.; Otsuka, T.; Sieja, K.; Tostevin, J. A.; Tsunoda, Y.; Authelet, G.; Baba, H.; Calvet, D.; Château, A.; Chen, S.; Corsi, A.; Delbart, A.; Gheller, J. M.; Giganon, A.; Gillibert, A.; Isobe, T.; Lapoux, V.; Matsushita, M.; Momiyama, S.; Motobayashi, T.; Niikura, M.; Otsu, H.; Paul, N.; Péron, C.; Peyaud, A.; Pollacco, E. C.; Roussé, J.-Y.; Sakurai, H.; Santamaria, C.; Sasano, M.; Shiga, Y.; Steppenbeck, D.; Takeuchi, S.; Taniuchi, R.; Uesaka, T.; Wang, H.; Yoneda, K.; Ando, T.; Arici, T.; Blazhev, A.; Browne, F.; Bruce, A. M.; Carroll, R. J.; Chung, L. X.; Cortés, M. L.; Dewald, M.; Ding, B.; Dombrádi, Zs.; Flavigny, F.; Franchoo, S.; Giacoppo, F.; Gottardo, A.; Hadyńska-Klęk, K.; Jungclaus, A.; Korkulu, Z.; Koyama, S.; Kubota, Y.; Lee, J.; Lettmann, M.; Linh, B. D.; Liu, J.; Liu, Z.; Lizarazo, C.; Louchart, C.; Lozeva, R.; Matsui, K.; Miyazaki, T.; Moschner, K.; Nagamine, M.; Nakatsuka, N.; Nishimura, S.; Nita, C. R.; Nobs, C. R.; Olivier, L.; Ota, S.; Orlandi, R.; Patel, Z.; Regan, P. H.; Rudigier, M.; Şahin, E.; Saito, T.; Söderström, P.-A.; Stefan, I.; Sumikama, T.; Suzuki, D.; Vajta, Zs.; Vaquero, V.; Werner, V.; Wimmer, K.; Wu, J.; Xu, Z. Y.

2017-10-01

We report on the measurement of new low-lying states in the neutron-rich 81,82,83,84Zn nuclei via in-beam γ-ray spectroscopy. These include the 41+ → 21+ transition in 82Zn, the 21+ → 0g.s.+ and 41+ → 21+ transitions in 84Zn, and low-lying states in 81,83Zn were observed for the first time. The reduced E ( 21+) energies and increased E (41+) / E (2+1) ratios at N = 52, 54 compared to those in 80Zn attest that the magicity is confined to the neutron number N = 50 only. The deduced level schemes are compared to three state-of-the-art shell model calculations and a good agreement is observed with all three calculations. The newly observed 2+ and 4+ levels in 84Zn suggest the onset of deformation towards heavier Zn isotopes, which has been incorporated by taking into account the upper sdg orbitals in the Ni78-II and the PFSDG-U models.

Tables of E2 transition probabilities from the first 2 + states in even-even nuclei [B(E2) evaluation for 0 + 1 → 2 + 1 transitions in even-even nuclei

DOE PAGES

Pritychenko, B.; Birch, M.; Singh, B.; ...

2015-11-03

A complete B(E2)↑ evaluation and compilation for even-even nuclei has been presented. The present paper is a continuation of P.H. Stelson and L. Grodzins, and S. Raman et al. nuclear data evaluations and was motivated by a large number of new measurements. It extends the list of evaluated nuclides from 328 to 452, includes an extended list of nuclear reaction kinematics parameters and comprehensive shell model analysis. Evaluation policies for analysis of experimental data have been discussed and conclusions are given. Moreover, future plans for B(E2)↑ systematics and experimental technique analyses of even-even nuclei are outlined.

High resolution in-beam γ-ray spectroscopy

NASA Astrophysics Data System (ADS)

Kern, J.; Dousse, J.-Cl.; Gasser, M.; Perny, B.; Rhême, Ch.

1985-01-01

An in-beam curved crystal facility has been installed at the SIN variable energy cyclotron. Using the (110) planes of a 3.0 mm thick quartz lamina bent at 3.15 m, diffraction peaks typically 6 arcsec wide (FWHM) are obtained. The energy resolution is thus, for instance, 110 eV at 170 keV in 3rd order. Due to a sophisticated detector system and heavy shielding, the sensitivity of the instrument is quite good. The facility proves quite useful in (p,xnγ) reaction studies whenever the γ-ray spectrum is very complex, e.g. in the study of odd-odd deformed nuclei. Complicated multiplets appearing in the 176Yb(p,3nγ)174Lu spectrum could be successfully resolved. From the results we derive that the g-factors of the 142 d, Jπ=6- isomer, take anomalous values.

Spin singlet and spin triplet pairing correlations on shape evolution in s d -shell N =Z Nuclei

NASA Astrophysics Data System (ADS)

Ha, Eunja; Cheoun, Myung-Ki; Sagawa, H.

2018-02-01

We study the shape evolution of N =Z nuclei 24Mg,28Si, and 32S in the axially symmetric deformed Woods-Saxon model, taking into account both T =0 and T =1 pairing interactions. We find the coexistence of T =0 and T =1 superfluidity phases in the large deformation region | β2|>0.3 in these three nuclei. The interplay between the two pairing interactions has an important effect on determining the deformation of the ground states in these nuclei. The self-energy contributions from the pairing correlations to the single particle (s.p.) energies are also examined.

Precision investigations of nuclei and nucleons with the (e, e'. gamma. ) reaction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Papanicolas, C.N.; Ammons, E.A.; Cardman, L.S.

1988-11-20

Recent theoretical and experimental investigations of the (e, e'..gamma..) reaction show that it provides a probe of unparalleled precision and selectivity. Experiments aimed towards the isolation of multipole form factors in mixed transitions, the study of continuum excitations in nuclei, and the measurement of the response of the proton are underway at several laboratories.

Pocket formula for nuclear deformations of actinides

NASA Astrophysics Data System (ADS)

Manjunatha, H. C.; Sridhar, K. N.

2018-06-01

We have formulated a pocket formula for quadrupole (β2), octupole (β3), hexadecapole (β4) and hexacontatetrapole (β6) deformation of the nuclear ground state of all isotopes of actinide nuclei (89 < Z < 103). This formula is first of its kind and produces a nuclear deformation of all isotopes actinide nuclei 89 < Z < 103 with simple inputs of Z and A. Hence, this formula is useful in the fields of nuclear physics to study the structure and interaction of nuclei.

{Delta}I = 2 energy staggering in normal deformed dysprosium nuclei

DOE Office of Scientific and Technical Information (OSTI.GOV)

Riley, M.A.; Brown, T.B.; Archer, D.E.

1996-12-31

Very high spin states (I{ge}50{Dirac_h}) have been observed in {sup 155,156,157}Dy. The long regular band sequences, free from sharp backbending effects, observed in these dysprosium nuclei offer the possibility of investigating the occurence of any {Delta}I = 2 staggering in normal deformed nuclei. Employing the same analysis techniques as used in superdeformed nuclei, certain bands do indeed demonstrate an apparent staggering and this is discussed.

Role of deformation in odd-even staggering in reaction cross sections for 30,31,32Ne and 36,37,38Mg isotopes

NASA Astrophysics Data System (ADS)

Urata, Y.; Hagino, K.; Sagawa, H.

2017-12-01

We discuss the role of pairing antihalo effect in the observed odd-even staggering in reaction cross sections for 30,31,32Ne and 36,37,38Mg isotopes by taking into account the ground-state deformation of these nuclei. To this end, we construct the ground-state density for the Ne,3130 and Mg,3736 nuclei based on a deformed Woods-Saxon potential, while for the 32Ne and 38Mg nuclei we also take into account the pairing correlation using the Hartree-Fock-Bogoliubov method. We demonstrate that, when the one-neutron separation energy is small for the odd-mass nuclei, a significant odd-even staggering still appears even with finite deformation, although the degree of staggering is somewhat reduced compared to the spherical case. This implies that the pairing antihalo effect in general plays an important role in generating the odd-even staggering in reaction cross sections for weakly bound nuclei.

Spontaneous fission of the end product in α-decay chain of recoiled superheavy nucleus: A theoretical study

NASA Astrophysics Data System (ADS)

Kaur, Amandeep; Sawhney, Gudveen; Sharma, Manoj K.; Gupta, Raj K.

The temperature-dependent preformed cluster model [PCM(T)] is employed to extend our recent work [Niyti, G. Sawhney, M. K. Sharma and R. K. Gupta, Phys. Rev. C 91 (2015) 054606] on α-decay chains of various isotopes of Z = 113-118 superheavy nuclei (SHN), to spontaneous fissioning nuclei 103266Lr, 104267Rf, 105266‑268Db, 111281Rg, and 112282Cn occurring as end products of these α-decay chains. The behavior of fragment mass distribution and competitive emergence of the dominant decay mode, i.e., the α-emission versus spontaneous fission (SF), are studied for identifying the most probable heavy fission fragments, along with the estimation of SF half-life times T1/2SF and total kinetic energy (TKE) of the above noted isotopes of Z = 103-112 nuclei decaying via the SF process. The mass distributions of chosen nuclei are clearly symmetric, independent of mass and temperature. The most preferred decay fragment is found to lie in the neighborhood of doubly magic shell closures of Z = 50 and N = 82, with largest preformation factor P0. In addition, a comparative study of the “hot compact” and “cold elongated” configurations of β2i-deformed and 𝜃iopt-oriented nuclei indicates significantly different behaviors of the two mass fragmentation yields, favoring “hot compact” configuration.

Octupole deformation in odd-odd nuclei

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sheline, R.K.

1988-01-01

Comparison of the experimental and theoretical ground-state spins of odd-odd nuclei in the region 220less than or equal toAless than or equal to228 generally shows agreement with a folded Yukawa octupole deformed model with epsilon/sub 3/ = 0.08 and some lack of agreement with the same model with epsilon/sub 3/ = 0. Thus in spite of limited spectroscopic information, the ground-state spins suggest the existence of octupole deformation in odd-odd nuclei in the region 220less than or equal toAless than or equal to228.

Multiplication free neural network for cancer stem cell detection in H-and-E stained liver images

NASA Astrophysics Data System (ADS)

Badawi, Diaa; Akhan, Ece; Mallah, Ma'en; Üner, Ayşegül; ćetin-Atalay, Rengül; ćetin, A. Enis

2017-05-01

Markers such as CD13 and CD133 have been used to identify Cancer Stem Cells (CSC) in various tissue images. It is highly likely that CSC nuclei appear as brown in CD13 stained liver tissue images. We observe that there is a high correlation between the ratio of brown to blue colored nuclei in CD13 images and the ratio between the dark blue to blue colored nuclei in H&E stained liver images. Therefore, we recommend that a pathologist observing many dark blue nuclei in an H&E stained tissue image may also order CD13 staining to estimate the CSC ratio. In this paper, we describe a computer vision method based on a neural network estimating the ratio of dark blue to blue colored nuclei in an H&E stained liver tissue image. The neural network structure is based on a multiplication free operator using only additions and sign operations. Experimental results are presented.

Derivation of an optical potential for statically deformed rare-earth nuclei from a global spherical potential

DOE PAGES

Nobre, G. P. A.; Palumbo, A.; Herman, M.; ...

2015-02-25

The coupled-channel theory is a natural way of treating nonelastic channels, in particular those arising from collective excitations characterized by nuclear deformations. A proper treatment of such excitations is often essential to the accurate description of experimental nuclear-reaction data and to the prediction of a wide variety of scattering observables. Stimulated by recent work substantiating the near validity of the adiabatic approximation in coupled-channel calculations for scattering on statically deformed nuclei, we explore the possibility of generalizing a global spherical optical model potential (OMP) to make it usable in coupled-channel calculations on this class of nuclei. To do this, wemore » have deformed the Koning-Delaroche global spherical potential for neutrons, coupling a sufficient number of states of the ground state band to ensure convergence. We present an extensive study of the effects of collective couplings and nuclear deformations on integrated cross sections as well as on angular distributions for neutron-induced reactions on statically deformed nuclei in the rare-earth region. We choose isotopes of three rare-earth elements (Gd, Ho, W), which are known to be nearly perfect rotors, to exemplify the results of the proposed method. Predictions from our model for total, elastic and inelastic cross sections, as well as for elastic and inelastic angular distributions, are in reasonable agreement with measured experimental data. In conclusion, these results suggest that the deformed Koning-Delaroche potential provides a useful regional neutron optical potential for the statically deformed rare earth nuclei.« less

Calculating Absolute Transition Probabilities for Deformed Nuclei in the Rare-Earth Region

NASA Astrophysics Data System (ADS)

Stratman, Anne; Casarella, Clark; Aprahamian, Ani

2017-09-01

Absolute transition probabilities are the cornerstone of understanding nuclear structure physics in comparison to nuclear models. We have developed a code to calculate absolute transition probabilities from measured lifetimes, using a Python script and a Mathematica notebook. Both of these methods take pertinent quantities such as the lifetime of a given state, the energy and intensity of the emitted gamma ray, and the multipolarities of the transitions to calculate the appropriate B(E1), B(E2), B(M1) or in general, any B(σλ) values. The program allows for the inclusion of mixing ratios of different multipolarities and the electron conversion of gamma-rays to correct for their intensities, and yields results in absolute units or results normalized to Weisskopf units. The code has been tested against available data in a wide range of nuclei from the rare earth region (28 in total), including 146-154Sm, 154-160Gd, 158-164Dy, 162-170Er, 168-176Yb, and 174-182Hf. It will be available from the Notre Dame Nuclear Science Laboratory webpage for use by the community. This work was supported by the University of Notre Dame College of Science, and by the National Science Foundation, under Contract PHY-1419765.

Role of hexadecapole deformation of projectile 28Si in heavy-ion fusion reactions near the Coulomb barrier

NASA Astrophysics Data System (ADS)

Kaur, Gurpreet; Hagino, K.; Rowley, N.

2018-06-01

The vast knowledge regarding the strong influence of quadrupole deformation β2 of colliding nuclei in heavy-ion sub-barrier fusion reactions inspires a desire to quest the sensitivity of fusion dynamics to higher order deformations, such as β4 and β6 deformations. However, such studies have rarely been carried out, especially for deformation of projectile nuclei. In this article, we investigated the role of β4 of the projectile nucleus in the fusion of the 28Si+92Zr system. We demonstrated that the fusion barrier distribution is sensitive to the sign and value of the β4 parameter of the projectile, 28Si, and confirmed that the 28Si nucleus has a large positive β4. This study opens an indirect way to estimate deformation parameters of radioactive nuclei using fusion reactions, which is otherwise difficult because of experimental constraints.

Population and decay of a Kπ=8- two-quasineutron isomer in 244Pu

NASA Astrophysics Data System (ADS)

Hota, S. S.; Tandel, S. K.; Chowdhury, P.; Ahmad, I.; Carpenter, M. P.; Chiara, C. J.; Greene, J. P.; Hoffman, C. R.; Jackson, E. G.; Janssens, R. V. F.; Kay, B. P.; Khoo, T. L.; Kondev, F. G.; Lakshmi, S.; Lalkovski, S.; Lauritsen, T.; Lister, C. J.; McCutchan, E. A.; Moran, K.; Peterson, D.; Shirwadkar, U.; Seweryniak, D.; Stefanescu, I.; Toh, Y.; Zhu, S.

2016-08-01

The decay of a Kπ=8- isomer in 244Pu and the collective band structures populating the isomer were studied using deep inelastic excitations with 47Ti and 208Pb beams, respectively. Precise measurements of M 1 /E 2 branching ratios in the band confirm a 9 /2-[734] ν⊗7 /2+[624] ν configuration assignment for the isomer, validating the systematics of Kπ=8- , two-quasineutron isomers observed in even-Z , N =150 isotones. These isomers around the deformed shell gap at N =152 provide critical benchmarks for theoretical predictions of single-particle energies in this gateway region to superheavy nuclei.

Masses and β -Decay Spectroscopy of Neutron-Rich Odd-Odd Eu,162160 Nuclei: Evidence for a Subshell Gap with Large Deformation at N =98

NASA Astrophysics Data System (ADS)

Hartley, D. J.; Kondev, F. G.; Orford, R.; Clark, J. A.; Savard, G.; Ayangeakaa, A. D.; Bottoni, S.; Buchinger, F.; Burkey, M. T.; Carpenter, M. P.; Copp, P.; Gorelov, D. A.; Hicks, K.; Hoffman, C. R.; Hu, C.; Janssens, R. V. F.; Klimes, J. W.; Lauritsen, T.; Sethi, J.; Seweryniak, D.; Sharma, K. S.; Zhang, H.; Zhu, S.; Zhu, Y.

2018-05-01

The structure of deformed neutron-rich nuclei in the rare-earth region is of significant interest for both the astrophysics and nuclear structure fields. At present, a complete explanation for the observed peak in the elemental abundances at A ˜160 eludes astrophysicists, and models depend on accurate quantities, such as masses, lifetimes, and branching ratios of deformed neutron-rich nuclei in this region. Unusual nuclear structure effects are also observed, such as the unexpectedly low energies of the first 2+ levels in some even-even nuclei at N =98 . In order to address these issues, mass and β -decay spectroscopy measurements of the Eu97 160 and Eu99 162 nuclei were performed at the Californium Rare Isotope Breeder Upgrade radioactive beam facility at Argonne National Laboratory. Evidence for a gap in the single-particle neutron energies at N =98 and for large deformation (β2˜0.3 ) is discussed in relation to the unusual phenomena observed at this neutron number.

Shell-model method for Gamow-Teller transitions in heavy deformed odd-mass nuclei

NASA Astrophysics Data System (ADS)

Wang, Long-Jun; Sun, Yang; Ghorui, Surja K.

2018-04-01

A shell-model method for calculating Gamow-Teller (GT) transition rates in heavy deformed odd-mass nuclei is presented. The method is developed within the framework of the projected shell model. To implement the computation requirement when many multi-quasiparticle configurations are included in the basis, a numerical advancement based on the Pfaffian formula is introduced. With this new many-body technique, it becomes feasible to perform state-by-state calculations for the GT nuclear matrix elements of β -decay and electron-capture processes, including those at high excitation energies in heavy nuclei which are usually deformed. The first results, β- decays of the well-deformed A =153 neutron-rich nuclei, are shown as the example. The known log(f t ) data corresponding to the B (GT- ) decay rates of the ground state of 153Nd to the low-lying states of 153Pm are well described. It is further shown that the B (GT) distributions can have a strong dependence on the detailed microscopic structure of relevant states of both the parent and daughter nuclei.

Octupole deformations in high-K isomeric states of heavy and superheavy nuclei

NASA Astrophysics Data System (ADS)

Minkov, N.; Walker, P. M.

2016-01-01

We study the effects of quadrupole-octupole deformations on the energy and magnetic properties of high-K isomeric states in even-even heavy and superheavy nuclei. The neutron two-quasiparticle (2qp) isomeric energies and magnetic dipole moments are calculated within a deformed shell model with the Bardeen-Cooper- Schrieffer (BCS) pairing interaction over a wide range of quadrupole and octupole deformations. We found that in most cases the magnetic moments exhibit a pronounced sensitivity to the octupole deformation, while the 2qp energies indicate regions of nuclei in which the presence of high-K isomeric states may be associated with the presence of octupole softness or even with octupole deformation. In the present work we also examine the influence of the BCS pairing strength on the energy of the blocked isomer configuration. We show that the formation of 2qp energy minima in the space of quadrupole-octupole and eventually higher multipolarity deformations is a subtle effect depending on nuclear pairing correlations.

Single-particle states vs. collective modes: friends or enemies ?

NASA Astrophysics Data System (ADS)

Otsuka, T.; Tsunoda, Y.; Togashi, T.; Shimizu, N.; Abe, T.

2018-05-01

The quantum self-organization is introduced as one of the major underlying mechanisms of the quantum many-body systems. In the case of atomic nuclei as an example, two types of the motion of nucleons, single-particle states and collective modes, dominate the structure of the nucleus. The collective mode arises as the balance between the effect of the mode-driving force (e.g., quadrupole force for the ellipsoidal deformation) and the resistance power against it. The single-particle energies are one of the sources to produce such resistance power: a coherent collective motion is more hindered by larger spacings between relevant single particle states. Thus, the single-particle state and the collective mode are "enemies" against each other. However, the nuclear forces are rich enough so as to enhance relevant collective mode by reducing the resistance power by changing single-particle energies for each eigenstate through monopole interactions. This will be verified with the concrete example taken from Zr isotopes. Thus, the quantum self-organization occurs: single-particle energies can be self-organized by (i) two quantum liquids, e.g., protons and neutrons, (ii) monopole interaction (to control resistance). In other words, atomic nuclei are not necessarily like simple rigid vases containing almost free nucleons, in contrast to the naïve Fermi liquid picture. Type II shell evolution is considered to be a simple visible case involving excitations across a (sub)magic gap. The quantum self-organization becomes more important in heavier nuclei where the number of active orbits and the number of active nucleons are larger.

Description of deformed nuclei in the sdg boson model

NASA Astrophysics Data System (ADS)

Li, S. C.; Kuyucak, S.

1996-02-01

We present a study of deformed nuclei in the framework of the sdg interacting boson model utilizing both numerical diagonalization and analytical {1}/{N} expansion techniques. The focus is on the description of high-spin states which have recently become computationally accessible through the use of computer algebra in the {1}/{N} expansion formalism. A systematic study is made of high-spin states in rare-earth and actinide nuclei.

Evolution of deformation in neutron-rich Ba isotopes up to A =150

NASA Astrophysics Data System (ADS)

Licǎ, R.; Benzoni, G.; Rodríguez, T. R.; Borge, M. J. G.; Fraile, L. M.; Mach, H.; Morales, A. I.; Madurga, M.; Sotty, C. O.; Vedia, V.; De Witte, H.; Benito, J.; Bernard, R. N.; Berry, T.; Bracco, A.; Camera, F.; Ceruti, S.; Charviakova, V.; Cieplicka-Oryńczak, N.; Costache, C.; Crespi, F. C. L.; Creswell, J.; Fernandez-Martínez, G.; Fynbo, H.; Greenlees, P. T.; Homm, I.; Huyse, M.; Jolie, J.; Karayonchev, V.; Köster, U.; Konki, J.; Kröll, T.; Kurcewicz, J.; Kurtukian-Nieto, T.; Lazarus, I.; Lund, M. V.; Mǎrginean, N.; Mǎrginean, R.; Mihai, C.; Mihai, R. E.; Negret, A.; Orduz, A.; Patyk, Z.; Pascu, S.; Pucknell, V.; Rahkila, P.; Rapisarda, E.; Regis, J. M.; Robledo, L. M.; Rotaru, F.; Saed-Samii, N.; Sánchez-Tembleque, V.; Stanoiu, M.; Tengblad, O.; Thuerauf, M.; Turturica, A.; Van Duppen, P.; Warr, N.; IDS Collaboration

2018-02-01

The occurrence of octupolar shapes in the Ba isotopic chain was recently established experimentally up to N =90 . To further extend the systematics, the evolution of shapes in the most neutron-rich members of the Z =56 isotopic chain accessible at present, Ba,150148, has been studied via β decay at the ISOLDE Decay Station. This paper reports on the first measurement of the positive- and negative-parity low-spin excited states of 150Ba and presents an extension of the β -decay scheme of 148Cs. Employing the fast timing technique, half-lives for the 21+ level in both nuclei have been determined, resulting in T1 /2=1.51 (1 ) ns for 148Ba and T1 /2=3.4 (2 ) ns for 150Ba. The systematics of low-spin states, together with the experimental determination of the B (E 2 :2+→0+) transition probabilities, indicate an increasing collectivity in Ba-150148, towards prolate deformed shapes. The experimental data are compared to symmetry conserving configuration mixing (SCCM) calculations, confirming an evolution of increasingly quadrupole deformed shapes with a definite octupolar character.

Analytic Description of Critical Point Nuclei in a Spherical-Axially Deformed Shape Phase Transition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Iachello, F.

2001-07-30

An approximate solution at the critical point of the spherical to axially deformed shape phase transition in nuclei is presented. The eigenvalues of the Hamiltonian are expressed in terms of zeros of Bessel functions of irrational order.

Charged lepton flavor violation in a class of radiative neutrino mass generation models

NASA Astrophysics Data System (ADS)

Chowdhury, Talal Ahmed; Nasri, Salah

2018-04-01

We investigate the charged lepton flavor violating processes μ →e γ , μ →e e e ¯, and μ -e conversion in nuclei for a class of three-loop radiative neutrino mass generation models with electroweak multiplets of increasing order. We find that, because of certain cancellations among various one-loop diagrams which give the dipole and nondipole contributions in an effective μ e γ vertex and a Z-penguin contribution in an effective μ e Z vertex, the flavor violating processes μ →e γ and μ -e conversion in nuclei become highly suppressed compared to μ →e e e ¯ process. Therefore, the observation of such a pattern in LFV processes may reveal the radiative mechanism behind neutrino mass generation.

Nuclear Deformation at Finite Temperature

NASA Astrophysics Data System (ADS)

Alhassid, Y.; Gilbreth, C. N.; Bertsch, G. F.

2014-12-01

Deformation, a key concept in our understanding of heavy nuclei, is based on a mean-field description that breaks the rotational invariance of the nuclear many-body Hamiltonian. We present a method to analyze nuclear deformations at finite temperature in a framework that preserves rotational invariance. The auxiliary-field Monte Carlo method is used to generate a statistical ensemble and calculate the probability distribution associated with the quadrupole operator. Applying the technique to nuclei in the rare-earth region, we identify model-independent signatures of deformation and find that deformation effects persist to temperatures higher than the spherical-to-deformed shape phase-transition temperature of mean-field theory.

Half-lives of α -decaying nuclei in the medium-mass region within the transfer matrix method

NASA Astrophysics Data System (ADS)

Wu, Shuangxiang; Qian, Yibin; Ren, Zhongzhou

2018-05-01

The α -decay half-lives of even-even nuclei from Sm to Th are systematically studied based on the transfer matrix method. For the nuclear potential, a type of cosh-parametrized form is applied to calculate the penetration probability. Through a least-squares fit to experimental half-lives, we optimize the parameters in the potential and the α preformation factor P0. During this process, P0 is treated as a constant for each parent nucleus. Eventually, the calculated half-lives are found to agree well with the experimental data, which verifies the accuracy of the present approach. Furthermore, in recent studies, P0 is regulated by the shell and paring effects plus the nuclear deformation. To this end, P0 is here associated with the structural quantity, i.e., the microscopic correction of nuclear mass (Emic). In this way, the agreement between theory and experiment is greatly improved by more than 20%, validating the appropriate treatment of P0 in the scheme of Emic.

Adiabatically describing rare earths using microscopic deformations

NASA Astrophysics Data System (ADS)

Nobre, Gustavo; Dupuis, Marc; Herman, Michal; Brown, David

2017-09-01

Recent works showed that reactions on well-deformed nuclei in the rare-earth region are very well described by an adiabatic method. This assumes a spherical optical potential (OP) accounting for non-rotational degrees of freedom while the deformed configuration is described by couplings to states of the g.s. rotational band. This method has, apart from the global OP, only the deformation parameters as inputs, with no additional fit- ted variables. For this reason, it has only been applied to nuclei with well-measured deformations. With the new computational capabilities, microscopic large-scale calculations of deformation parameters within the HFB method based on the D1S Gogny force are available in the literature. We propose to use such microscopic deformations in our adi- abatic method, allowing us to reproduce the cross sections agreements observed in stable nuclei, and to reliably extend this description to nuclei far from stability, describing the whole rare-earth region. Since all cross sections, such as capture and charge exchange, strongly depend on the correct calculation of absorption from the incident channel (from direct reaction mechanisms), this approach significantly improves the accuracy of cross sections and transitions relevant to astrophysical studies. The work at BNL was sponsored by the Office of Nuclear Physics, Office of Science of the US Department of Energy, under Contract No. DE-AC02-98CH10886 with Brookhaven Science Associates, LLC.

Resource Letter NSM-1: New insights into the nuclear shell model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dean, David Jarvis; Hamilton, J. H.

2011-01-01

This Resource Letter provides a guide to the literature on the spherical shell model as applied to nuclei. The nuclear shell model describes the structure of nuclei starting with a nuclear core developed by the classical neutron and proton magic numbers N,Z=2,8,20,28,50,82, 126, where gaps occur in the single-particle energies as a shell is filled, and the interactions of valence nucleons that reside beyond that core. Various modern extensions of this model for spherical nuclei are likewise described. Significant extensions of the nuclear shell model include new magic numbers for spherical nuclei and now for deformed nuclei as well. Whenmore » both protons and neutrons have shell gaps at the same spherical or deformed shapes, they can reinforce each other to give added stability to that shape and lead to new magic numbers. The vanishings of the classical spherical shell model energy gaps and magic numbers in new neutron-rich nuclei are described. Spherical and deformed shell gaps are seen to be critical for the existence of elements with Z > 100.« less

Generation of high-energy neutron beam by fragmentation of relativistic heavy nuclei

NASA Astrophysics Data System (ADS)

Yurevich, Vladimir

2016-09-01

The phenomenon of multiple production of neutrons in reactions with heavy nuclei induced by high-energy protons and light nuclei is analyzed using a Moving Source Model. The Lorentz transformation of the obtained neutron distributions is used to study the neutron characteristics in the inverse kinematics where relativistic heavy nuclei bombard a light-mass target. The neutron beam generated at 0∘has a Gaussian shape with a maximum at the energy of the projectile nucleons and an energy resolution σE/E < 4% above 6 GeV.

Sub-barrier quasifission in heavy element formation reactions with deformed actinide target nuclei

NASA Astrophysics Data System (ADS)

Hinde, D. J.; Jeung, D. Y.; Prasad, E.; Wakhle, A.; Dasgupta, M.; Evers, M.; Luong, D. H.; du Rietz, R.; Simenel, C.; Simpson, E. C.; Williams, E.

2018-02-01

Background: The formation of superheavy elements (SHEs) by fusion of two massive nuclei is severely inhibited by the competing quasifission process. Low excitation energies favor SHE survival against fusion-fission competition. In "cold" fusion with spherical target nuclei near 208Pb, SHE yields are largest at beam energies significantly below the average capture barrier. In "hot" fusion with statically deformed actinide nuclei, this is not the case. Here the elongated deformation-aligned configurations in sub-barrier capture reactions inhibits fusion (formation of a compact compound nucleus), instead favoring rapid reseparation through quasifission. Purpose: To determine the probabilities of fast and slow quasifission in reactions with prolate statically deformed actinide nuclei, through measurement and quantitative analysis of the dependence of quasifission characteristics at beam energies spanning the average capture barrier energy. Methods: The Australian National University Heavy Ion Accelerator Facility and CUBE fission spectrometer have been used to measure fission and quasifission mass and angle distributions for reactions with projectiles from C to S, bombarding Th and U target nuclei. Results: Mass-asymmetric quasifission occurring on a fast time scale, associated with collisions with the tips of the prolate actinide nuclei, shows a rapid increase in probability with increasing projectile charge, the transition being centered around projectile atomic number ZP=14 . For mass-symmetric fission events, deviations of angular anisotropies from expectations for fusion fission, indicating a component of slower quasifission, suggest a similar transition, but centered around ZP˜8 . Conclusions: Collisions with the tips of statically deformed prolate actinide nuclei show evidence for two distinct quasifission processes of different time scales. Their probabilities both increase rapidly with the projectile charge. The probability of fusion can be severely suppressed by these two quasifission processes, since the sub-barrier heavy element yield is likely to be determined by the product of the probabilities of surviving each quasifission process.

The nucleus is irreversibly shaped by motion of cell boundaries in cancer and non-cancer cells.

PubMed

Tocco, Vincent J; Li, Yuan; Christopher, Keith G; Matthews, James H; Aggarwal, Varun; Paschall, Lauren; Luesch, Hendrik; Licht, Jonathan D; Dickinson, Richard B; Lele, Tanmay P

2018-02-01

Actomyosin stress fibers impinge on the nucleus and can exert compressive forces on it. These compressive forces have been proposed to elongate nuclei in fibroblasts, and lead to abnormally shaped nuclei in cancer cells. In these models, the elongated or flattened nuclear shape is proposed to store elastic energy. However, we found that deformed shapes of nuclei are unchanged even after removal of the cell with micro-dissection, both for smooth, elongated nuclei in fibroblasts and abnormally shaped nuclei in breast cancer cells. The lack of shape relaxation implies that the nuclear shape in spread cells does not store any elastic energy, and the cellular stresses that deform the nucleus are dissipative, not static. During cell spreading, the deviation of the nucleus from a convex shape increased in MDA-MB-231 cancer cells, but decreased in MCF-10A cells. Tracking changes of nuclear and cellular shape on micropatterned substrata revealed that fibroblast nuclei deform only during deformations in cell shape and only in the direction of nearby moving cell boundaries. We propose that motion of cell boundaries exert a stress on the nucleus, which allows the nucleus to mimic cell shape. The lack of elastic energy in the nuclear shape suggests that nuclear shape changes in cells occur at constant surface area and volume. © 2017 Wiley Periodicals, Inc.

Population and decay of a K π = 8 – two-quasineutron isomer in Pu 244

DOE PAGES

Hota, S. S.; Tandel, S. K.; Chowdhury, P.; ...

2016-08-22

Here, the decay of a K π = 8 – isomer in 244Pu and the collective band structures populating the isomer were studied using deep inelastic excitations with 47Ti and 208Pb beams, respectively. Precise measurements of M1/E2 branching ratios in the band confirm a 9/2 –[734] νⓍ7/2 +[624] ν configuration assignment for the isomer, validating the systematics of K π = 8 –, two-quasineutron isomers observed in even-Z, N = 150 isotones. These isomers around the deformed shell gap at N = 152 provide critical benchmarks for theoretical predictions of single-particle energies in this gateway region to superheavy nuclei.

Population and decay of a K π = 8 – two-quasineutron isomer in Pu 244

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hota, S. S.; Tandel, S. K.; Chowdhury, P.

Here, the decay of a K π = 8 – isomer in 244Pu and the collective band structures populating the isomer were studied using deep inelastic excitations with 47Ti and 208Pb beams, respectively. Precise measurements of M1/E2 branching ratios in the band confirm a 9/2 –[734] νⓍ7/2 +[624] ν configuration assignment for the isomer, validating the systematics of K π = 8 –, two-quasineutron isomers observed in even-Z, N = 150 isotones. These isomers around the deformed shell gap at N = 152 provide critical benchmarks for theoretical predictions of single-particle energies in this gateway region to superheavy nuclei.

Spin-dependent μ → e conversion

DOE PAGES

Cirigliano, Vincenzo; Davidson, Sacha; Kuno, Yoshitaka

2017-05-22

The experimental sensitivity to μ→e conversion on nuclei is expected to improve by four orders of magnitude in coming years. Here, we consider the impact of μ→e flavour-changing tensor and axial-vector four-fermion operators which couple to the spin of nucleons. Such operators, which have not previously been considered, contribute to μ→e conversion in three ways: in nuclei with spin they mediate a spin-dependent transition; in all nuclei they contribute to the coherent (A 2-enhanced) spin-independent conversion via finite recoil effects and via loop mixing with dipole, scalar, and vector operators. Furthermore, we estimate the spin-dependent rate in Aluminium (the targetmore » of the upcoming COMET and Mu2e experiments), show that the loop effects give the greatest sensitivity to tensor and axial-vector operators involving first-generation quarks, and discuss the complementarity of the spin-dependent and independent contributions to μ→e conversion.« less

Spin-dependent μ → e conversion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cirigliano, Vincenzo; Davidson, Sacha; Kuno, Yoshitaka

The experimental sensitivity to μ→e conversion on nuclei is expected to improve by four orders of magnitude in coming years. Here, we consider the impact of μ→e flavour-changing tensor and axial-vector four-fermion operators which couple to the spin of nucleons. Such operators, which have not previously been considered, contribute to μ→e conversion in three ways: in nuclei with spin they mediate a spin-dependent transition; in all nuclei they contribute to the coherent (A 2-enhanced) spin-independent conversion via finite recoil effects and via loop mixing with dipole, scalar, and vector operators. Furthermore, we estimate the spin-dependent rate in Aluminium (the targetmore » of the upcoming COMET and Mu2e experiments), show that the loop effects give the greatest sensitivity to tensor and axial-vector operators involving first-generation quarks, and discuss the complementarity of the spin-dependent and independent contributions to μ→e conversion.« less

High-lying Gamow-Teller excited states in the deformed nuclei,76Ge,82Se and N = 20 nuclei in the island of inversion by the Deformed QRPA (DQRPA)

NASA Astrophysics Data System (ADS)

Cheoun, Myung-Ki; Ha, Eunja

2013-07-01

With the advent of high analysis technology in detecting the Gamow-Teller (GT) excited states beyond one nucleon emission threshold, the quenching of the GT strength to the Ikeda sum rule (ISR) seems to be recovered by the high-lying (HL) GT states. We address that these HL GT excited states result from the smearing of the Fermi surface by the increase of the chemical potential owing to the deformation within a framework of the deformed quasi-particle random phase approximation (DQRPA). Detailed mechanism leading to the smearing is discussed, and comparisons to the available experimental data on 76Ge,82Se and N = 20 nuclei are shown to explain the strong peaks on the HL GT excited states.

A probabilistic template of human mesopontine tegmental nuclei from in vivo 7T MRI.

PubMed

Bianciardi, Marta; Strong, Christian; Toschi, Nicola; Edlow, Brian L; Fischl, Bruce; Brown, Emery N; Rosen, Bruce R; Wald, Lawrence L

2018-04-15

Mesopontine tegmental nuclei such as the cuneiform, pedunculotegmental, oral pontine reticular, paramedian raphe and caudal linear raphe nuclei, are deep brain structures involved in arousal and motor function. Dysfunction of these nuclei is implicated in the pathogenesis of disorders of consciousness and sleep, as well as in neurodegenerative diseases. However, their localization in conventional neuroimages of living humans is difficult due to limited image sensitivity and contrast, and a stereotaxic probabilistic neuroimaging template of these nuclei in humans does not exist. We used semi-automatic segmentation of single-subject 1.1mm-isotropic 7T diffusion-fractional-anisotropy and T 2 -weighted images in healthy adults to generate an in vivo probabilistic neuroimaging structural template of these nuclei in standard stereotaxic (Montreal Neurological Institute, MNI) space. The template was validated through independent manual delineation, as well as leave-one-out validation and evaluation of nuclei volumes. This template can enable localization of five mesopontine tegmental nuclei in conventional images (e.g. 1.5T, 3T) in future studies of arousal and motor physiology (e.g. sleep, anesthesia, locomotion) and pathology (e.g. disorders of consciousness, sleep disorders, Parkinson's disease). The 7T magnetic resonance imaging procedure for single-subject delineation of these nuclei may also prove useful for future 7T studies of arousal and motor mechanisms. Copyright © 2017 Elsevier Inc. All rights reserved.

Half-Lives of Proton Emitters With a Deformed Density-Dependent Model

NASA Astrophysics Data System (ADS)

Qian, Yi-Bin; Ren, Zhong-Zhou; Ni, Dong-Dong; Sheng, Zong-Qiang

2010-11-01

Half-lives of proton radioactivity are investigated with a deformed density-dependent model. The single folding potential which is dependent on deformation and orientation is employed to calculate the proton decay width through the deformed potential barrier. In addition, the spectroscopic factor is taken into account in the calculation, which is obtained in the relativistic mean field theory with NL3. The calculated results of semi-spherical nuclei are found to be in good agreement with the experimental data, and the results of well-deformed nuclei are also satisfactory. Moreover, a formula for the spherical proton emission half-life based on the Gamow quantum tunneling theory is presented.

Final-state interactions in two-nucleon knockout reactions

NASA Astrophysics Data System (ADS)

Colle, Camille; Cosyn, Wim; Ryckebusch, Jan

2016-03-01

Background: Exclusive two-nucleon knockout after electroexcitation of nuclei [A (e ,e'N N ) in brief] is considered to be a primary source of information about short-range correlations (SRCs) in nuclei. For a proper interpretation of the data, final-state interactions (FSIs) need to be theoretically controlled. Purpose: Our goal is to quantify the role of FSI effects in exclusive A (e ,e'p N ) reactions for four target nuclei representative of the whole mass region. Our focus is on processes that are SRC driven. We investigate the role of FSIs for two characteristic detector setups corresponding to "small" and "large" coverage of the available phase space. Method: Use is made of a factorized expression for the A (e ,e'p N ) cross section that is proportional to the two-body center-of-mass (c.m.) momentum distribution of close-proximity pairs. The A (e ,e'p p ) and A (e ,e'p n ) reactions for the target nuclei 12C,27Al,56Fe, and 208Pb are investigated. The elastic attenuation mechanisms in the FSIs are included using the relativistic multiple-scattering Glauber approximation (RMSGA). Single-charge exchange (SCX) reactions are also included. We introduce the nuclear transparency TAp N, defined as the ratio of exclusive (e ,e'p N ) cross sections on nuclei to those on "free" nucleon pairs, as a measure for the aggregated effect of FSIs in p N knockout reactions from nucleus A . A toy model is introduced in order to gain a better understanding of the A dependence of TAp N. Results: The transparency TAp N drops from 0.2 -0.3 for 12C to 0.04 -0.07 for 208Pb. For all considered kinematics, the mass dependence of TAp N can be captured by the power law TAp N∝A-λ with 0.4 ≲λ ≲0.5 . Apart from an overall reduction factor, we find that FSIs only modestly affect the distinct features of SRC-driven A (e ,e'p N ) which are dictated by the c.m. distribution of close-proximity pairs. Conclusion: The SCX mechanisms represent a relatively small (order of a few percent) contribution of SRC-driven A (e ,e'p N ) processes. The mass dependence of FSI effects in exclusive A (e ,e'p N ) can be captured in a robust power law and is in agreement with the predictions obtained in a toy model.

Open sd-shell nuclei from first principles

DOE PAGES

Jansen, Gustav R.; Signoracci, Angelo J.; Hagen, Gaute; ...

2016-07-05

We extend the ab initio coupled-cluster effective interaction (CCEI) method to open-shell nuclei with protons and neutrons in the valence space, and compute binding energies and excited states of isotopes of neon and magnesium. We employ a nucleon-nucleon and three-nucleon interaction from chiral effective field theory evolved to a lower cutoff via a similarity renormalization group transformation. We find good agreement with experiment for binding energies and spectra, while charge radii of neon isotopes are underestimated. For the deformed nuclei 20Ne and 24Mg we reproduce rotational bands and electric quadrupole transitions within uncertainties estimated from an effective field theory formore » deformed nuclei, thereby demonstrating that collective phenomena in sd-shell nuclei emerge from complex ab initio calculations.« less

Open sd-shell nuclei from first principles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jansen, Gustav R.; Signoracci, Angelo J.; Hagen, Gaute

We extend the ab initio coupled-cluster effective interaction (CCEI) method to open-shell nuclei with protons and neutrons in the valence space, and compute binding energies and excited states of isotopes of neon and magnesium. We employ a nucleon-nucleon and three-nucleon interaction from chiral effective field theory evolved to a lower cutoff via a similarity renormalization group transformation. We find good agreement with experiment for binding energies and spectra, while charge radii of neon isotopes are underestimated. For the deformed nuclei 20Ne and 24Mg we reproduce rotational bands and electric quadrupole transitions within uncertainties estimated from an effective field theory formore » deformed nuclei, thereby demonstrating that collective phenomena in sd-shell nuclei emerge from complex ab initio calculations.« less

Neck formation and deformation effects in a preformed cluster model of exotic cluster decays

NASA Astrophysics Data System (ADS)

Kumar, Satish; Gupta, Raj K.

1997-01-01

Using the nuclear proximity approach and the two center nuclear shape parametrization, the interaction potential between two deformed and pole-to-pole oriented nuclei forming a necked configuration in the overlap region is calculated and its role is studied for the cluster decay half-lives. The barrier is found to move to a larger relative separation, with its proximity minimum lying in the neighborhood of the Q value of decay and its height and width reduced considerably. For cluster decay calculations in the preformed cluster model of Malik and Gupta, due to deformations and orientations of nuclei, the (empirical) preformation factor is found to get reduced considerably and agrees nicely with other model calculations known to be successful for their predictions of cluster decay half-lives. Comparison with the earlier case of nuclei treated as spheres suggests that the effects of both deformations and neck formation get compensated by choosing the position of cluster preformation and the inner classical turning point for penetrability calculations at the touching configuration of spherical nuclei.

Synthesis reactions and radioactive properties of transactinoid elements

NASA Astrophysics Data System (ADS)

Oganessian, Yu. Ts.

1994-10-01

It is well known that the heaviest elements of the periodic table have been synthesized in the cold fusion of magic nuclei of Pb with Z less than 26 ions. Because of dynamic limitations for fusion under strong Coulomb interaction of nuclei, the cross-sections of cold fusion reactions diminish exponentially with growing compound nucleus atomic number. For element Z = 110 produced in the reaction Pb-208(Ni-62,n)(sub 271)110, the expected cross-section is 10(exp -36) sq cm. In still more asymmetric reactions, when isotopes of actinoid elements irradiated with relatively light ions (Z less than or equal 12) are used as the target material, the compound nuclei possess an excitation energy of approx. 50 MeV. At this energy the nuclear shell effects are strongly suppressed and, as a result, in the case of hot compound nuclei of transactinoid elements the fission barrier is practically absent. The transition of these nuclei into the ground state depends strongly on the dynamic properties of the system with respect to the fission degree of freedom. Experimental studies were going on in two directions: (1) determination of the fission time by measuring the prefission neutrons (of Cf-Fm nuclei) in a wide interval of excitation energies; (2) direct synthesis of known nuclides with Z = 102-105 in reactions with ions of Ne-22, Mg-26, Al-27 and P-31 when final nuclei are produced in the ground state after the evaporation of five or six neutrons from the excited compound nuclei (E(sub x) = 50-60 MeV). The dependence of the reaction cross-section (HI, 5-6n) on the atomic number of the compound nucleus in different target-ion combinations points to the possibility of synthesizing new elements in hot fusion reactions. The advantage of these reactions arises from the use of neutron-rich nuclei like Cm-248 and Cf-249 which allows us to synthesize nuclei close to the deformed shell N = 162, for which a considerable growth of stability against spontaneous fission is predicted. Experimental set-ups and methods of detecting rare events of formation and decay of transactinide nuclei are described.

Study of Cold Fusion Reactions Using Collective Clusterization Approach

NASA Astrophysics Data System (ADS)

Kaur, Gurjit; Sandhu, Kirandeep; Sharma, Manoj K.

2017-10-01

Within the framework of the dynamical cluster decay model (DCM), the 1n evaporation cross-sections ({σ }1n) of cold fusion reactions (Pb and Bi targets) are calculated for {Z}{CN}=104-113 superheavy nuclei. The calculations are carried out in the fixed range of excitation energy {E}{CN}* =15+/- 1 {MeV}, so that the comparative analysis of reaction dynamics can be worked out. First of all, the fission barriers (B f ) and neutron separation energies ({S}1n) are estimated to account the decreasing cross-sections of cold fusion reactions. In addition to this, the importance of hot optimum orientations of β 2i-deformed nuclei over cold one is explored at fixed angular momentum and neck-length parameters. The hot optimum orientations support all the target-projectile (t,p) combinations, which are explored experimentally in the cold fusion reactions. Some new target-projectile combinations are also predicted for future exploration. Further, the 1n cross-sections are addressed for {Z}{CN}=104-113 superheavy nuclei at comparable excitation energies which show the decent agrement with experimental data upto {Z}{CN}=109 nuclei. Finally, to understand the dynamics of higher-Z superheavy nuclei, the cross-sections are also calculated at maximum available energies around the Coulomb barrier and the effect of non-sticking moment of inertia ({I}{NS}) is also investigated at these energies. Supported by the Council of Scientific and Industrial Research (CSIR), in the Form of Research Project Grant No. 03(1341)/15/EMR-II, and to DST, New Delhi, for INSPIRE-Fellowship Grant No. DST/INSPIRE/03/2015/000199

Unexpected Decrease in Moment of Inertia Between N = 98-100 in 162,164Gd

NASA Astrophysics Data System (ADS)

Jones, E. F.; Hamilton, J. H.; Gore, P. M.; Ramayya, A. V.; Hwang, J. K.; Delima, A. P.; Zhu, S. J.; Beyer, C. J.; Luo, Y. X.; Kormicki, J.; Zhang, X. Q.; Ma, W. C.; Rasmussen, J. O.; Lee, I. Y.; Wu, S. C.; Folden, C. M.; Fallon, P.; Zielinski, P.; Gregorich, K. E.; Macchiavelli, A. O.; Ginter, T. N.; Stoyer, M.; Cole, J. D.; Janssens, R. V. F.; Ahmad, I.; Daniel, A. V.; Ter-Akopian, G. M.; Oganessian, Yu. Ts.; Donangelo, R.; Asztalos, S. J.

2003-10-01

From γ-γ-γ coincidence studies of the prompt γ-rays emitted in the spontaneous fission (SF) of 252Cf with Gammasphere, the yrast energy levels in neutron-rich 162,164Gd were identified for the first time from 2+ to 16+ and from 2+ to 14+, respectively. The 2+ level energies are 71.6 and 73.3 keV in 162,164Gd, respectively. The transition energies from every level in 164Gd are higher than those from the same levels in 162Gd. There is a systematic decrease at every level of the moment of inertia (MOI) and similarly β2 deformation in N = 100 164Gd compared to N = 98 162Gd. The minimum in E(2+) and maxima in MOI and β2 occur at N = 98. This behavior is unexpected compared to the E(2+) and β2 trends in Er, Yb, and Hf nuclei where the minima and maxima occur at neutron midshell, N = 104.

Strongly deformed nuclear shapes at ultra-high spin and shape coexistence in N ~ 90 nuclei

DOE PAGES

Riley, M. A.; Aguilar, A.; Evans, A. O.; ...

2009-01-01

The N ~ 90 region of the nuclear chart has featured prominently as the spectroscopy of nuclei at extreme spin has progressed. This talk will present recent discoveries from investigations of high spin behavior in the N ~ 90 Er, Tm and Yb nuclei utilizing the Gammasphere gamma-ray spectrometer. In particular it will include discussion of the beautiful shape evolution and coexistence observed in these nuclei along with the identification of a remarkable new family of band structures. The latter are very weakly populated rotational sequences with high moment of inertia that bypass the classic terminating configurations near spin 40-50h,more » marking a return to collectivity that extends discrete γ-ray spectroscopy to well over 60h. Establishing the nature of the yrast states in these nuclei beyond the oblate band-termination states has been a major goal for the past two decades. Cranking calculations suggest that these new structures most likely represent stable triaxial strongly deformed bands that lie in a valley of favored shell energy in deformation and particle-number space.« less

Effective field theory of emergent symmetry breaking in deformed atomic nuclei

DOE PAGES

Papenbrock, Thomas F.; Weidenmüller, H. A.

2015-09-03

Spontaneous symmetry breaking in non-relativistic quantum systems has previously been addressed in the framework of effective field theory. Low-lying excitations are constructed from Nambu–Goldstone modes using symmetry arguments only. In this study, we extend that approach to finite systems. The approach is very general. To be specific, however, we consider atomic nuclei with intrinsically deformed ground states. The emergent symmetry breaking in such systems requires the introduction of additional degrees of freedom on top of the Nambu–Goldstone modes. Symmetry arguments suffice to construct the low-lying states of the system. Lastly, in deformed nuclei these are vibrational modes each of whichmore » serves as band head of a rotational band.« less

Hauser-Feshbach calculations in deformed nuclei

DOE PAGES

Grimes, S. M.

2013-08-22

Hauser Feshbach calculations for deformed nuclei are typically done with level densities appropriate for deformed nuclei but with Hauser Feshbach codes which enforce spherical symmetry by not including K as a parameter in the decay sums. A code has been written which does allow the full K dependence to be included. Calculations with the code have been compared with those from a conventional Hauser Feshbach code. The evaporation portion (continuum) is only slightly affected by this change but the cross sections to individual (resolved) levels are changed substantially. It is found that cross sections to neighboring levels with the samemore » J but differing K are not the same. The predicted consequences of K mixing will also be discussed.« less

Evolutional schemes for objects with active nuclei

NASA Technical Reports Server (NTRS)

Komberg, B. V.

1979-01-01

The observational properties of quasistellar objects (QSO) reveal that they are extremely violent nuclei of distant galaxies, but the evolutionary stage of these galaxies is still undetermined. Various published attempts to classify QSO under different criteria - including the one based on the morphological type of the surrounding galaxy E- or S- are analyzed. There are evidences that radioactive quasars reside in E-, while radio-quiet quasars reside in both E- and S- systems. The latter may be evolutionary connected to Seyfert-like objects. A correlation between the nuclei activity level in systems of different morphological type and the relative amount of gas in them is noted. From the point of view of activity level and the duration of active stage of nuclei it is concluded that an interaction of galaxies with the intergalactic medium is of particular importance and must be most conspicuous in spheriodal systems of central regions of rich clusters, in tight groups and binary galaxies.

/B(E2) values from low-energy Coulomb excitation at an ISOL facility: the /N=80,82 Te isotopes

NASA Astrophysics Data System (ADS)

Barton, C. J.; Caprio, M. A.; Shapira, D.; Zamfir, N. V.; Brenner, D. S.; Gill, R. L.; Lewis, T. A.; Cooper, J. R.; Casten, R. F.; Beausang, C. W.; Krücken, R.; Novak, J. R.

2003-01-01

B(E2;0+1→2+1) values for the unstable, neutron-rich nuclei 132,134Te were determined through Coulomb excitation, in inverse kinematics, of accelerated beams of these nuclei. The systematics of measured B(E2) values from the ground state to the first excited state have been extended to the N=82 shell closure in the Te nuclei and have been compared with the predictions of different theories. The measurements were performed at the Holifield Radioactive Ion Beam Facility (HRIBF) using the GRAFIK detector. The success of this approach, which couples a 5.7% efficient through-well NaI(Tl) γ-ray detector with thin foil microchannel plate beam detectors, also demonstrates the feasibility for Coulomb excitation studies of neutron-rich nuclei even further from the valley of beta stability, both at present-generation ISOL facilities and at the proposed Rare Isotope Accelerator.

Study of hot thermally fissile nuclei using relativistic mean field theory

NASA Astrophysics Data System (ADS)

Quddus, Abdul; Naik, K. C.; Patra, S. K.

2018-07-01

We have studied the properties of hot 234,236U and 240Pu nuclei in the framework of relativistic mean field formalism. The recently developed FSUGarnet and IOPB-I parameter sets are implemented for the first time to deform nuclei at finite temperature. The results are compared with the well known NL3 set. The said isotopes are structurally important because of the thermally fissile nature of 233,235U and 239Pu as these nuclei (234,236U and 240Pu) are formed after the absorption of a thermal neutron, which undergoes fission. Here, we have evaluated the nuclear properties, such as shell correction energy, neutron-skin thickness, quadrupole and hexadecapole deformation parameters and asymmetry energy coefficient for these nuclei as a function of temperature.

[Influence of estradiol on tryptophan hydroxylase and 5-hydroxytryptamine content in raphe nuclei of rats under forced swimming stress].

PubMed

Yang, Fu-zhong; Wu, Yan; Zhang, Wei-guo; Cai, Yi-yun; Shi, Shen-xun

2010-07-20

To investigate the effect of estradiol (E2) on tryptophan hydroxylase (TPH) and 5-hydroxytryptamine (5-HT) content in raphe nuclei of rats under forced swimming stress and explore the role of estrogen and stress in disease mechanism of depression in women. At Week 3 post-ovariectomy, 35 ovariectomized (OVX) female SD rats were randomly divided into 5 groups (n = 7): non-stress group, control group, estradiol (E2) group and fluoxetine (FLX) group and E2 plus FLX group. Animals were administered with different drugs for 2 weeks. At Day 14, animals except those in the non-stress group were subjected to the 15 min forced swimming test (FST). At 2 hours post-FST, all animals including those in the non-stress group were perfused with 4% paraformaldehyde and brains removed for TPH and 5-HT immunofluorescence staining. We compared the content of TPH and 5-HT by observing and calculating the integrated optical density (IOD) of immunofluorescent-positive signals in raphe nuclei. (1) The IOD value of TPH- and 5-HT-positive region in raphe nuclei of rats in the control group was significantly lower than that of the non-stress group (P < 0.01); (2) the IOD value of TPH- and 5-HT-positive region in raphe nuclei of rats in the E2, FLX and E2 plus FLX groups was significantly higher than that in the control group (P < 0.05). Forced swimming stress can decrease the TPH and 5-HT content in raphe nuclei. Such changes can be prevented by a pre-administration of estradiol. Similar results are observed with antidepressant fluoxetine. These effects may underlie the role of estradiol and stress in the disease mechanism of depression in women.

The B(E2;4^+1->2^+1) / B(E2;2^+1->0^+1) Ratio in Even-Even Nuclei

NASA Astrophysics Data System (ADS)

Loelius, C.; Sharon, Y. Y.; Zamick, L.; G"Urdal, G.

2009-10-01

We considered 207 even-even nuclei throughout the chart of nuclides for which the NNDC Tables had data on the energies and lifetimes of the 2^+1 and 4^+1 states. Using these data we calculated for each nucleus the electric quadrupole transition strengths B(E2;4^+1->2^+1) and B(E2;2^+1->0^+1), as well as their ratio. The internal conversion coefficients were obtained by using the NNDC HSICC calculator. For each nucleus we plotted the B(E2) ratio against A, N, and Z. We found that for close to 90% of the nuclei considered the ratio had values between 0.5 and 2.5. Most of the outliers had magic numbers of protons or neutrons. Our ratio results were compared with the theoretical predictions for this ratio by different models--10/7 in the rotational model and 2 in the simplest vibrational model. In the rotational regions (for 150 < A < 180 and A > 220) the ratios were indeed close to 10/7. For the few nuclei thought to be vibrational the ratios were usually less than 2. Otherwise, we got a wide scatter of ratio values. Hence other models, including the NpNn scheme, must be considered in interpreting these results.

Prenatal caffeine intake differently affects synaptic proteins during fetal brain development.

PubMed

Mioranzza, Sabrina; Nunes, Fernanda; Marques, Daniela M; Fioreze, Gabriela T; Rocha, Andréia S; Botton, Paulo Henrique S; Costa, Marcelo S; Porciúncula, Lisiane O

2014-08-01

Caffeine is the psychostimulant most consumed worldwide. However, little is known about its effects during fetal brain development. In this study, adult female Wistar rats received caffeine in drinking water (0.1, 0.3 and 1.0 g/L) during the active cycle in weekdays, two weeks before mating and throughout pregnancy. Cerebral cortex and hippocampus from embryonic stages 18 or 20 (E18 or E20, respectively) were collected for immunodetection of the following synaptic proteins: brain-derived neurotrophic factor (BDNF), TrkB receptor, Sonic Hedgehog (Shh), Growth Associated Protein 43 (GAP-43) and Synaptosomal-associated Protein 25 (SNAP-25). Besides, the estimation of NeuN-stained nuclei (mature neurons) and non-neuronal nuclei was verified in both brain regions and embryonic periods. Caffeine (1.0 g/L) decreased the body weight of embryos at E20. Cortical BDNF at E18 was decreased by caffeine (1.0 g/L), while it increased at E20, with no major effects on TrkB receptors. In the hippocampus, caffeine decreased TrkB receptor only at E18, with no effects on BDNF. Moderate and high doses of caffeine promoted an increase in Shh in both brain regions at E18, and in the hippocampus at E20. Caffeine (0.3g/L) decreased GAP-43 only in the hippocampus at E18. The NeuN-stained nuclei increased in the cortex at E20 by lower dose and in the hippocampus at E18 by moderate dose. Our data revealed that caffeine transitorily affect synaptic proteins during fetal brain development. The increased number of NeuN-stained nuclei by prenatal caffeine suggests a possible acceleration of the telencephalon maturation. Although some modifications in the synaptic proteins were transient, our data suggest that caffeine even in lower doses may alter the fetal brain development. Copyright © 2014 ISDN. Published by Elsevier Ltd. All rights reserved.

Evolution of E 2 transition strength in deformed hafnium isotopes from new measurements on 172Hf,174Hf, and 176Hf

NASA Astrophysics Data System (ADS)

Rudigier, M.; Nomura, K.; Dannhoff, M.; Gerst, R.-B.; Jolie, J.; Saed-Samii, N.; Stegemann, S.; Régis, J.-M.; Robledo, L. M.; Rodríguez-Guzmán, R.; Blazhev, A.; Fransen, Ch.; Warr, N.; Zell, K. O.

2015-04-01

Background: The available data for E 2 transition strengths in the region between neutron-deficient hafnium and platinum isotopes are far from complete. More and precise data are needed to enhance the picture of structure evolution in this region and to test state-of-the-art nuclear models. In a simple model, the maximum collectivity is expected at the middle of the major shell. However, for actual nuclei, particularly in heavy-mass regions, which should be highly complex, this picture may no longer be the case, and one should use a more realistic nuclear-structure model. We address this point by studying the spectroscopy of Hf as a representative case. Purpose: We remeasure the 21+ half-lives of 172,174,176Hf, for which there is some disagreement in the literature. The main goal is to measure, for the first time, the half-lives of higher-lying states of the rotational band. The new results are compared to a theoretical calculation for absolute transition strengths. Method: The half-lives were measured using γ -γ and conversion-electron-γ delayed coincidences with the fast timing method. For the determination of half-lives in the picosecond region, the generalized centroid difference method was applied. For the theoretical calculation of the spectroscopic properties, the interacting boson model is employed, whose Hamiltonian is determined based on microscopic energy-density functional calculations. Results: The measured 21+ half-lives disagree with results from earlier γ -γ fast timing measurements, but are in agreement with data from Coulomb excitation experiments and other methods. Half-lives of the 41+ and 61+ states were measured, as well as a lower limit for the 81+ states. Conclusions: This work shows the importance of a mass-dependent effective boson charge in the interacting boson model for the description of E 2 transition rates in chains of nuclei. It encourages further studies of the microscopic origin of this mass dependence. New experimental values on transition rates in nuclei from neighboring isotopic chains could support these studies.

The quest for novel modes of excitation in exotic nuclei

NASA Astrophysics Data System (ADS)

Paar, N.

2010-06-01

This paper provides an insight into several open problems in the quest for novel modes of excitation in nuclei with isospin asymmetry, deformation and finite-temperature characteristics in stellar environments. Major unsolved problems include the nature of pygmy dipole resonances, the quest for various multipole and spin-isospin excitations both in neutron-rich and proton drip-line nuclei mainly driven by loosely bound nucleons, excitations in unstable deformed nuclei and evolution of their properties with the shape phase transition. Exotic modes of excitation in nuclei at finite temperatures characteristic of supernova evolution present open problems with a possible impact in modeling astrophysically relevant weak interaction rates. All these issues challenge self-consistent many-body theory frameworks at the frontiers of on-going research, including nuclear energy density functionals, both phenomenological and constrained by the strong interaction physics of QCD, models based on low-momentum two-nucleon interaction Vlow-k and correlated realistic nucleon-nucleon interaction VUCOM, supplemented by three-body force, as well as two-nucleon and three-nucleon interactions derived from the chiral effective field theory. Joined theoretical and experimental efforts, including research with radioactive isotope beams, are needed to provide insight into dynamical properties of nuclei away from the valley of stability, involving the interplay of isospin asymmetry, deformation and finite temperature.

Adaptive segmentation of nuclei in H&S stained tendon microscopy

NASA Astrophysics Data System (ADS)

Chuang, Bo-I.; Wu, Po-Ting; Hsu, Jian-Han; Jou, I.-Ming; Su, Fong-Chin; Sun, Yung-Nien

2015-12-01

Tendiopathy is a popular clinical issue in recent years. In most cases like trigger finger or tennis elbow, the pathology change can be observed under H and E stained tendon microscopy. However, the qualitative analysis is too subjective and thus the results heavily depend on the observers. We develop an automatic segmentation procedure which segments and counts the nuclei in H and E stained tendon microscopy fast and precisely. This procedure first determines the complexity of images and then segments the nuclei from the image. For the complex images, the proposed method adopts sampling-based thresholding to segment the nuclei. While for the simple images, the Laplacian-based thresholding is employed to re-segment the nuclei more accurately. In the experiments, the proposed method is compared with the experts outlined results. The nuclei number of proposed method is closed to the experts counted, and the processing time of proposed method is much faster than the experts'.

Feasibility of Harvesting Radon from FRIB Beam Dump

DOE Office of Scientific and Technical Information (OSTI.GOV)

Visser, A.; Scielzo, N.

The observation of a permanent electric dipole moment (EDM) in an atom would signal a long-soughtafter presence of time-reversal violation and would have far reaching consequences for both particle physics and cosmology. Currently, the most stringent limitation on time-reversal violating effects in the nucleus comes from studies of stable 199Hg. However, for certain nuclei which have an octupole deformed shape, such as 223Rn, the time-reversal violating interactions are expected to be 100-1000 times greater than in 199Hg (Auerbach et al. 1996). As a result, there is great interest in searching for EDMs in octupole deformed nuclei and some of themore » initial studies of these nuclei have been featured on the cover of the journal Nature (Gaffney et al. 2013). All the octupole deformed nuclei of interest are radioactive and therefore available only in limited quantities. The primary challenge for an EDM experiment using radon is to collect large enough samples to perform sensitive searches.« less

Fission of actinide nuclei using multi-nucleon transfer reactions

NASA Astrophysics Data System (ADS)

Léguillon, Romain; Nishio, Katsuhisa; Hirose, Kentaro; Orlandi, Riccardo; Makii, Hiroyuki; Nishinaka, Ichiro; Ishii, Tetsuro; Tsukada, Kazuaki; Asai, Masato; Chiba, Satoshi; Ohtsuki, Tsutomu; Araki, Shohei; Watanabe, Yukinobu; Tatsuzawa, Ryotaro; Takaki, Naoyuki

2014-09-01

We are promoting a campaign to measure fission-fragment mass distributions for neutron-rich actinide nuclei populated by transfer reactions from their ground state up to an excitation energy of several tens MeV. We thus obtain the excitation energy dependence of the mass distribution. The experiment was carried out at the 20 MV JAEA tandem facility at Tokai. We report on the data obtained in the direct reaction 18 O + 232 Th . Transfer-channels and excitation energies of the fissioning nuclei were identified using silicon dE-E detectors located at forward angle. Two fission fragments were detected in coincidence using multi-wire proportional counters. Fission fragment masses were determined by kinematic consideration. We obtained the fission fragment mass distributions for 13 nuclei from actinium to uranium and some fission barrier heights. We are promoting a campaign to measure fission-fragment mass distributions for neutron-rich actinide nuclei populated by transfer reactions from their ground state up to an excitation energy of several tens MeV. We thus obtain the excitation energy dependence of the mass distribution. The experiment was carried out at the 20 MV JAEA tandem facility at Tokai. We report on the data obtained in the direct reaction 18 O + 232 Th . Transfer-channels and excitation energies of the fissioning nuclei were identified using silicon dE-E detectors located at forward angle. Two fission fragments were detected in coincidence using multi-wire proportional counters. Fission fragment masses were determined by kinematic consideration. We obtained the fission fragment mass distributions for 13 nuclei from actinium to uranium and some fission barrier heights. Present study is supported by the Ministry of Education, Culture, Sports, Science and Technology of Japan.

Lifetime Measurement of Nickel-58 Using RDM with GRETINA

NASA Astrophysics Data System (ADS)

Loelius, Charles

2014-09-01

The structure of nuclei near the doubly magic 56Ni has provided a sensitive probe of configuration mixing across the N=Z=28 shell gap. The shell model description of nuclei in this region is well established, with the gxpf1 interaction accurately reproducing the energy levels and transition strengths of Nuclei in the vicinity of 56Ni. However, there remain open questions as to the effects of higher lying orbitals beyond the pf shell. These can be addressed by a study of the B(E2)'s of nuclei in near the shell gap, particularly the B(E2;4+ -->2+) where effects of high l orbitals may be enhanced. 58Ni provides a strong candidate for study, as the only previous B(E2;4+ -->2+) measurement using the Doppler Shift Attenuation Method resulted in a B(E2) three times larger than that predicted by theory. In order to determine the possible effects of higher lying orbitals, a second measurement of the lifetime of 58Ni was undertaken at the National Superconducting Cyclotron Laboratory using the the Gamma-Ray Energy Tracking in Beam Nuclear Array (GRETINA) and the Recoil Distance Method (RDM). Preliminary results of this measurement will be presented.

Total Routhian surface calculations of triaxial or γ-soft properties in even- A N = 76 isotones with 54 ≤ Z ≤ 68

NASA Astrophysics Data System (ADS)

Yang, Qiong; Wang, Hua-Lei; Chai, Qing-Zhen; Liu, Min-Liang

2015-09-01

Total Routhian surface (TRS) calculations for even-even N = 76 isotones with 54 ≤ Z ≤ 68 have been performed in three-dimensional (β2, γ, β4) deformation space. Calculated results of the equilibrium deformations are presented and compared with other theoretical predictions and available experimental data. The behavior of collective angular momentum shows the neutron rotation-alignment is preferred in the lighter N = 76 isotones, while for the heavier ones the proton alignment is favored. Moreover, multi-pair nucleon alignments and their competition (e.g., in 144Er) are predicted. It is pointed out that these nuclei in the N = 76 isotonic chain exhibit triaxiality or γ softness in high-spin states as well as ground states. Based on deformation-energy curves with respect to axial and non-axial quadrupole deformations, the shape instabilities are evaluated in detail and predicted, particularly in γ direction. Such instabilities are also supported by the odd- and even-spin level staggering of the observed γ bands, which is usually used to distinguish between γ-rigid and γ7-soft asymmetry. Supported by National Natural Science Foundation of China (10805040, 11175217), Foundation and Advanced Technology Research Program of Henan Province(132300410125), S & T Research Key Program of Henan Province Education Department (13A140667)

Population of Nuclei Via 7Li-Induced Binary Reactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clark, Rodney M.; Phair, Larry W.; Descovich, M.

2005-08-08

The authors have investigated the population of nuclei formed in binary reactions involving {sup 7}Li beams on targets of {sup 160}Gd and {sup 184}W. The {sup 7}Li + {sup 184}W data were taken in the first experiment using the LIBERACE Ge-array in combination with the STARS Si {Delta}E-E telescope system at the 88-Inch Cyclotron of the Lawrence Berkeley National Laboratory. By using the Wilczynski binary transfer model, in combination with a standard evaporation model, they are able to reproduce the experimental results. This is a useful method for predicting the population of neutron-rich heavy nuclei formed in binary reactions involvingmore » beams of weakly bound nuclei formed in binary reactions involving beams of weakly bound nuclei and will be of use in future spectroscopic studies.« less

Systematic study of fission barriers of excited superheavy nuclei

NASA Astrophysics Data System (ADS)

Sheikh, J. A.; Nazarewicz, W.; Pei, J. C.

2009-07-01

A systematic study of fission-barrier dependence on excitation energy has been performed using the self-consistent finite-temperature Hartree-Fock + BCS (FT-HF + BCS) formalism with the SkM* Skyrme energy density functional. The calculations have been carried out for even-even superheavy nuclei with Z ranging between 110 and 124. For an accurate description of fission pathways, the effects of triaxial and reflection-asymmetric degrees of freedom have been fully incorporated. Our survey demonstrates that the dependence of isentropic fission barriers on excitation energy changes rapidly with particle number, pointing to the importance of shell effects even at large excitation energies characteristic of compound nuclei. The fastest decrease of fission barriers with excitation energy is predicted for deformed nuclei around N=164 and spherical nuclei around N=184 that are strongly stabilized by ground-state shell effects. For the nuclei Pu240 and Fm256, which exhibit asymmetric spontaneous fission, our calculations predict a transition to symmetric fission at high excitation energies owing to the thermal quenching of static reflection asymmetric deformations.

Low-lying electric-dipole strengths of Ca, Ni, and Sn isotopes imprinted on total reaction cross sections

NASA Astrophysics Data System (ADS)

Horiuchi, W.; Hatakeyama, S.; Ebata, S.; Suzuki, Y.

2017-08-01

Low-lying electric-dipole (E 1 ) strength of a neutron-rich nucleus contains information on neutron-skin thickness, deformation, and shell evolution. We discuss the possibility of making use of total reaction cross sections on 40Ca, 120Sn, and 208Pb targets to probe the E 1 strength of neutron-rich Ca, Ni, and Sn isotopes. They exhibit large enhancement of the E 1 strength at neutron number N >28 , 50, and 82, respectively, due to a change of the single-particle orbits near the Fermi surface participating in the transitions. The density distributions and the electric-multipole strength functions of those isotopes are calculated by the Hartree-Fock+BCS and the canonical-basis-time-dependent-Hartree-Fock-Bogoliubov methods, respectively, using three kinds of Skyrme-type effective interaction. The nuclear and Coulomb breakup processes are respectively described with the Glauber model and the equivalent photon method in which the effect of finite-charge distribution is taken into account. The three Skyrme interactions give different results for the total reaction cross sections because of different Coulomb breakup contributions. The contribution of the low-lying E 1 strength is amplified when the low-incident energy is chosen. With an appropriate choice of the incident energy and target nucleus, the total reaction cross section can be complementary to the Coulomb excitation for analyzing the low-lying E 1 strength of unstable nuclei.

Identification of significant E0 strength in the 22+ → 21+ transitions of 58,60,62Ni

NASA Astrophysics Data System (ADS)

Evitts, L. J.; Garnsworthy, A. B.; Kibédi, T.; Smallcombe, J.; Reed, M. W.; Brown, B. A.; Stuchbery, A. E.; Lane, G. J.; Eriksen, T. K.; Akber, A.; Alshahrani, B.; de Vries, M.; Gerathy, M. S. M.; Holt, J. D.; Lee, B. Q.; McCormick, B. P.; Mitchell, A. J.; Moukaddam, M.; Mukhopadhyay, S.; Palalani, N.; Palazzo, T.; Peters, E. E.; Ramirez, A. P. D.; Stroberg, S. R.; Tornyi, T.; Yates, S. W.

2018-04-01

The E0 transition strength in the 22+ →21 + transitions of 58,60,62Ni have been determined for the first time following a series of measurements at the Australian National University (ANU) and the University of Kentucky (UK). The CAESAR Compton-suppressed HPGe array and the Super-e solenoid at ANU were used to measure the δ (E 2 / M 1) mixing ratio and internal conversion coefficient of each transition following inelastic proton scattering. Level half-lives, δ (E 2 / M 1) mixing ratios and γ-ray branching ratios were measured at UK following inelastic neutron scattering. The new spectroscopic information was used to determine the E0 strengths. These are the first 2+ →2+E0 transition strengths measured in nuclei with spherical ground states and the E0 component is found to be unexpectedly large; in fact, these are amongst the largest E0 transition strengths in medium and heavy nuclei reported to date.

Single-particle Analyses of Compositions, Morphology, and Viscosity of Aerosol Particles Collected During GoAmazon2014

NASA Astrophysics Data System (ADS)

Adachi, K.; Gong, Z.; Bateman, A. P.; Martin, S. T.; Cirino, G. G.; Artaxo, P.; Sedlacek, A. J., III; Buseck, P. R.

2014-12-01

Single-particle analysis using transmission electron microscopy (TEM) shows composition and morphology of individual aerosol particles collected during the GoAmazon2014 campaign. These TEM results indicate aerosol types and mixing states, both of which are important for evaluating particle optical properties and cloud condensation nuclei activity. The samples were collected at the T3 site, which is located in the Amazon forest with influences from the urban pollution plume from Manaus. Samples were also collected from the T0 site, which is in the middle of the jungle with minimal to no influences of anthropogenic sources. The aerosol particles mainly originated from 1) anthropogenic pollution (e.g., nanosphere soot, sulfate), 2) biogenic emissions (e.g., primary biogenic particles, organic aerosols), and 3) long-range transport (e.g., sea salts). We found that the biogenic organic aerosol particles contain homogeneously distributed potassium. Particle viscosity is important for evaluating gas-particle interactions and atmospheric chemistry for the particles. Viscosity can be estimated from the rebounding behavior at controlled relative humidities, i.e., highly viscous particles display less rebound on a plate than low-viscosity particles. We collected 1) aerosol particles from a plate (non-rebounded), 2) those that had rebounded from the plate and were then captured onto an adjacent sampling plate, and 3) particles from ambient air using a separate impactor sampler. Preliminary results show that more than 90% of non-rebounded particles consisted of nanosphere soot with or without coatings. The coatings mostly consisted of organic matter. Although rebounded particles also contain nanosphere soot (number fraction 64-69%), they were mostly internally mixed with sulfate, organic matter, or their mixtures. TEM tilted images suggested that the rebounded particles were less deformed on the substrate, whereas the non-rebounded particles were more deformed, which could reflect differences in their viscosity.

Large-scale deformed QRPA calculations of the gamma-ray strength function based on a Gogny force

NASA Astrophysics Data System (ADS)

Martini, M.; Goriely, S.; Hilaire, S.; Péru, S.; Minato, F.

2016-01-01

The dipole excitations of nuclei play an important role in nuclear astrophysics processes in connection with the photoabsorption and the radiative neutron capture that take place in stellar environment. We present here the results of a large-scale axially-symmetric deformed QRPA calculation of the γ-ray strength function based on the finite-range Gogny force. The newly determined γ-ray strength is compared with experimental photoabsorption data for spherical as well as deformed nuclei. Predictions of γ-ray strength functions and Maxwellian-averaged neutron capture rates for Sn isotopes are also discussed.

Revisiting Grodzins systematics of B(E2) values

DOE PAGES

Pritychenko, B.; Birch, M.; Singh, B.

2017-04-03

Using Grodzins formalism, we analyze systematics of our latest evaluated B(E2) data for all the even–even nuclei in Z=2–104. The analysis indicates a low predictive power of systematics for a large number of cases, and a strong correlation between B(E2) fit values and nuclear structure effects. These findings provide a strong rationale for introduction of individual or elemental (grouped by Z) fit parameters. The current estimates of quadrupole collectivities for systematics of even–even nuclei yield complementary values for comparison with experimental results and theoretical calculations. Furthermore, the lists of fit parameters and predicted B(E2) values are given and possible implicationsmore » are discussed.« less

Semantic modeling of the structural and process entities during plastic deformation of crystals and rocks

NASA Astrophysics Data System (ADS)

Babaie, Hassan; Davarpanah, Armita

2016-04-01

We are semantically modeling the structural and dynamic process components of the plastic deformation of minerals and rocks in the Plastic Deformation Ontology (PDO). Applying the Ontology of Physics in Biology, the PDO classifies the spatial entities that participate in the diverse processes of plastic deformation into the Physical_Plastic_Deformation_Entity and Nonphysical_Plastic_Deformation_Entity classes. The Material_Physical_Plastic_Deformation_Entity class includes things such as microstructures, lattice defects, atoms, liquid, and grain boundaries, and the Immaterial_Physical_Plastic_Deformation_Entity class includes vacancies in crystals and voids along mineral grain boundaries. The objects under the many subclasses of these classes (e.g., crystal, lattice defect, layering) have spatial parts that are related to each other through taxonomic (e.g., Line_Defect isA Lattice_Defect), structural (mereological, e.g., Twin_Plane partOf Twin), spatial-topological (e.g., Vacancy adjacentTo Atom, Fluid locatedAlong Grain_Boundary), and domain specific (e.g., displaces, Fluid crystallizes Dissolved_Ion, Void existsAlong Grain_Boundary) relationships. The dynamic aspect of the plastic deformation is modeled under the dynamical Process_Entity class that subsumes classes such as Recrystallization and Pressure_Solution that define the flow of energy amongst the physical entities. The values of the dynamical state properties of the physical entities (e.g., Chemical_Potential, Temperature, Particle_Velocity) change while they take part in the deformational processes such as Diffusion and Dislocation_Glide. The process entities have temporal parts (phases) that are related to each other through temporal relations such as precedes, isSubprocessOf, and overlaps. The properties of the physical entities, defined under the Physical_Property class, change as they participate in the plastic deformational processes. The properties are categorized into dynamical, constitutive, spatial, temporal, statistical, and thermodynamical. The dynamical properties, categorized under the Dynamical_Rate_Property and Dynamical_State_Property classes, subsume different classes of properties (e.g., Fluid_Flow_Rate, Temperature, Chemical_Potential, Displacement, Electrical_Charge) based on the physical domain (e.g., fluid, heat, chemical, solid, electrical). The properties are related to the objects under the Physical_Entity class through diverse object type (e.g., physicalPropertyOf) and data type (e.g., Fluid_Pressure unit 'MPa') properties. The changes of the dynamical properties of the physical entities, described by the empirical laws (equations) modeled by experimental structural geologists, are modeled through the Physical_Property_Dependency class that subsumes the more specialized constitutive, kinetic, and thermodynamic expressions of the relationships among the dynamic properties. Annotation based on the PDO will make it possible to integrate and reuse experimental plastic deformation data, knowledge, and simulation models, and conduct semantic-based search of the source data originating from different rock testing laboratories.

Thalamus surface shape deformity in obsessive-compulsive disorder and schizophrenia.

PubMed

Kang, Do-Hyung; Kim, Sun Hyung; Kim, Chi-Won; Choi, Jung-Seok; Jang, Joon Hwan; Jung, Myung Hun; Lee, Jong-Min; Kim, Sun I; Kwon, Jun Soo

2008-04-16

The authors performed a three-dimensional shape deformation analysis to clarify the various patterns of specific thalamic nuclei abnormality using three age-matched and sex-matched groups of 22 patients with obsessive-compulsive disorder (OCD), 22 patients with schizophrenia and 22 control participants. Compared with the healthy volunteers, the anterior, lateral outward surface deformities of the thalamus were significant in OCD patients, whereas the posterior, medial outward deformities of the thalamus were prominent in schizophrenia patients. In terms of thalamic asymmetry, both OCD and schizophrenia patients exhibited the loss of a leftward pattern of asymmetry on the posterior, medial surface of the thalamus. Different patterns of shape abnormality of specific thalamic nuclei may be related to the different phenomenology of OCD and schizophrenia.

Hierarchical Distribution of the Tau Cytoskeletal Pathology in the Thalamus of Alzheimer's Disease Patients.

PubMed

Rüb, Udo; Stratmann, Katharina; Heinsen, Helmut; Del Turco, Domenico; Ghebremedhin, Estifanos; Seidel, Kay; den Dunnen, Wilfred; Korf, Horst-Werner

2016-01-01

In spite of considerable progress in neuropathological research on Alzheimer's disease (AD), knowledge regarding the exact pathoanatomical distribution of the tau cytoskeletal pathology in the thalamus of AD patients in the advanced Braak and Braak AD stages V or VI of the cortical cytoskeletal pathology is still fragmentary. Investigation of serial 100 μm-thick brain tissue sections through the thalamus of clinically diagnosed AD patients with Braak and Braak AD stage V or VI cytoskeletal pathologies immunostained with the anti-tau AT8 antibody, along with the affection of the extraterritorial reticular nucleus of the thalamus, reveals a consistent and severe tau immunoreactive cytoskeletal pathology in the limbic nuclei of the thalamus (e.g., paraventricular, anterodorsal and laterodorsal nuclei, limitans-suprageniculate complex). The thalamic nuclei integrated into the associative networks of the human brain (e.g., ventral anterior and mediodorsal nuclei) are only mildly affected, while its motor precerebellar (ventral lateral nucleus) and sensory nuclei (e.g., lateral and medial geniculate bodies, ventral posterior medial and lateral nuclei, parvocellular part of the ventral posterior medial nucleus) are more or less spared. The highly stereotypical and characteristic thalamic distribution pattern of the AD-related tau cytoskeletal pathology represents an anatomical mirror of the hierarchical topographic distribution of the cytoskeletal pathology in the interconnected regions of the cerebral cortex of AD patients. These pathoanatomical parallels support the pathophysiological concept of a transneuronal spread of the disease process of AD along anatomical pathways. The AD-related tau cytoskeletal pathology in the thalamus most likely contributes substantially to the neuropsychiatric disease symptoms (e.g., dementia), attention deficits, oculomotor dysfunctions, altered non-discriminative aspects of pain experience of AD patients, and the disruption of their waking and sleeping patterns.

Deformation dependence of the isovector giant dipole resonance: The neodymium isotopic chain revisited

NASA Astrophysics Data System (ADS)

Donaldson, L. M.; Bertulani, C. A.; Carter, J.; Nesterenko, V. O.; von Neumann-Cosel, P.; Neveling, R.; Ponomarev, V. Yu.; Reinhard, P.-G.; Usman, I. T.; Adsley, P.; Brummer, J. W.; Buthelezi, E. Z.; Cooper, G. R. J.; Fearick, R. W.; Förtsch, S. V.; Fujita, H.; Fujita, Y.; Jingo, M.; Kleinig, W.; Kureba, C. O.; Kvasil, J.; Latif, M.; Li, K. C. W.; Mira, J. P.; Nemulodi, F.; Papka, P.; Pellegri, L.; Pietralla, N.; Richter, A.; Sideras-Haddad, E.; Smit, F. D.; Steyn, G. F.; Swartz, J. A.; Tamii, A.

2018-01-01

Proton inelastic scattering experiments at energy Ep = 200 MeV and a spectrometer scattering angle of 0° were performed on 144,146,148,150Nd and 152Sm exciting the IsoVector Giant Dipole Resonance (IVGDR). Comparison with results from photo-absorption experiments reveals a shift of resonance maxima towards higher energies for vibrational and transitional nuclei. The extracted photo-absorption cross sections in the most deformed nuclei, 150Nd and 152Sm, exhibit a pronounced asymmetry rather than a distinct double-hump structure expected as a signature of K-splitting. This behaviour may be related to the proximity of these nuclei to the critical point of the phase shape transition from vibrators to rotors with a soft quadrupole deformation potential. Self-consistent random-phase approximation (RPA) calculations using the SLy6 Skyrme force provide a relevant description of the IVGDR shapes deduced from the present data.

Anisotropy and chemical composition of ultra-high energy cosmic rays using arrival directions measured by the Pierre Auger Observatory

DOE PAGES

Abreu, P

2011-06-17

The Pierre Auger Collaboration has reported evidence for anisotropy in the distribution of arrival directions of the cosmic rays with energies E > E th = 5.5 x 10 19 eV. These show a correlation with the distribution of nearby extragalactic objects, including an apparent excess around the direction of Centaurus A. If the particles responsible for these excesses at E > E th are heavy nuclei with charge Z, the proton component of the sources should lead to excesses in the same regions at energies E/Z. We here report the lack of anisotropies in these directions at energies abovemore » E th/Z (for illustrative values of Z = 6,13,26). If the anisotropies above E th are due to nuclei with charge Z, and under reasonable assumptions about the acceleration process, these observations imply stringent constraints on the allowed proton fraction at the lower energies.« less

The deformation stimulated luminescence in KCl, KBr and KI crystals

NASA Astrophysics Data System (ADS)

Shunkeyev, K.; Sergeyev, D.; Drozdowski, W.; Brylev, K.; Myasnikova, L.; Barmina, A.; Zhanturina, N.; Sagimbaeva, Sh; Aimaganbetova, Z.

2017-05-01

Currently, strengthening of the intensity of luminescence in alkali halide crystals (AHC) at lattice symmetry lowering is discussed as a promising direction for the development of scintillation detectors [1-3]. In this regard, for the study of anion excitons and radiation defects in the AHC anion sublattice at deformation, the crystals with the same sizes of cations and different sizes of anions were chosen. In the X-ray spectra of KCl at 10 K, the luminescence at 3.88 eV; 3.05 eV and 2.3 eV is clearly visible. The luminescence at 3.05 eV corresponds to the tunneling recharge [F*, H]. Luminescence at 3.88 eV is quenched in the region of thermal destruction of F‧-centers and characterizes tunneling recharge of F‧, VK-centers. In KCl at 90 K, the luminescence of self-trapped excitons (STE) is completely absent. In KBr at deformation not only STE luminescence, but also deformation stimulated luminescence at 3.58 eV were recorded, the last one corresponds to tunneling recharge of F‧, VK-centers. In KI crystal at 10 K and 90 K at deformation, only STE luminescence is enhanced. There are no deformation luminescence bands in KI compares with KBr and KCl crystals.

Spatiotemporal expression of Ezh2 in the developing mouse cochlear sensory epithelium.

PubMed

Chen, Yan; Li, Wenyan; Li, Wen; Chai, Renjie; Li, Huawei

2016-09-01

The enhancer of zeste 2 polycomb repressive complex 2 subunit (Ezh2) is a histone-lysine Nmethyltransferase enzyme that participates in DNA methylation. Ezh2 has also been reported to play crucial roles in stem cell proliferation and differentiation. However, the detailed expression profile of Ezh2 during mouse cochlear development has not been investigated. Here, we examined the spatiotemporal expression of Ezh2 in the cochlea during embryonic and postnatal development. Ezh2 expression began to be observed in the whole otocyst nuclei at embryonic day 9.5 (E9.5). At E12.5, Ezh2 was expressed in the nuclei of the cochlear prosensory epithelium. At E13.5 and E15.5, Ezh2 was expressed from the apical to the basal turns in the nuclei of the differentiating cochlear epithelium. At postnatal day (P) 0 and 7, the Ezh2 expression was located in the nuclei of the cochlear epithelium in all three turns and could be clearly seen in outer and inner hair cells, supporting cells, the stria vascularis, and spiral ganglion cells. Ezh2 continued to be expressed in the cochlear epithelium of adult mice. Our results provide the basic Ezh2 expression pattern and might be useful for further investigating the detailed role of Ezh2 during cochlear development.

Nuclear longitudinal form factors for axially deformed charge distributions expanded by nonorthogonal basis functions

NASA Astrophysics Data System (ADS)

Liu, Jian; Zhang, Jinjuan; Xu, Chang; Ren, Zhongzhou

2017-05-01

In this paper, the nuclear longitudinal form factors are systematically studied from the intrinsic charge multipoles. For axially deformed nuclei, two different types of density profiles are used to describe their charge distributions. For the same charge distributions expanded with different basis functions, the corresponding longitudinal form factors are derived and compared with each other. Results show the multipoles Cλ of longitudinal form factors are independent of the basis functions of charge distributions. Further numerical calculations of longitudinal form factors of 12C indicates that the C 0 multipole reflects the contributions of spherical components of all nonorthogonal basis functions. For deformed nuclei, their charge RMS radii can also be determined accurately by the C 0 measurement. The studies in this paper examine the model-independent properties of electron scattering, which are useful for interpreting electron scattering experiments on exotic deformed nuclei. Supported by National Natural Science Foundation of China (11505292, 11175085, 11575082, 11235001, 11275138, and 11447226), by Shandong Provincial Natural Science Foundation, China (BS2014SF007), Fundamental Research Funds for Central Universities (15CX02072A).

g-factor calculations from the generalized seniority approach

NASA Astrophysics Data System (ADS)

Maheshwari, Bhoomika; Jain, Ashok Kumar

2018-05-01

The generalized seniority approach proposed by us to understand the B(E1)/B(E2)/B(E3) properties of semi-magic nuclei has been widely successful in the explanation of the same and has led to an expansion in the scope of seniority isomers. In the present paper, we apply the generalized seniority scheme to understand the behavior of g-factors in semi-magic nuclei. We find that the magnetic moment and the gfactors do show a particle number independent behavior as expected and the understanding is consistent with the explanation of transition probabilities.

Hybrid theory and calculation of e-N2 scattering. [quantum mechanics - nuclei (nuclear physics)

NASA Technical Reports Server (NTRS)

Chandra, N.; Temkin, A.

1975-01-01

A theory of electron-molecule scattering was developed which was a synthesis of close coupling and adiabatic-nuclei theories. The theory is shown to be a close coupling theory with respect to vibrational degrees of freedom but is a adiabatic-nuclei theory with respect to rotation. It can be applied to any number of partial waves required, and the remaining ones can be calculated purely in one or the other approximation. A theoretical criterion based on fixed-nuclei calculations and not on experiment can be given as to which partial waves and energy domains require the various approximations. The theory allows all cross sections (i.e., pure rotational, vibrational, simultaneous vibration-rotation, differential and total) to be calculated. Explicit formulae for all the cross sections are presented.

Population of Nuclei Via 7Li-Induced Binary Reactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clark, R M; Phair, L W; Descovich, M

2005-08-09

The authors have investigated the population of nuclei formed in binary reactions involving {sup 7}Li beams on targets of {sup 160}Gd and {sup 184}W. The {sup 7}Li + {sup 184}W data were taken in the first experiment using the LIBERACE Ge-array in combination with the STARS Si {Delta}E-E telescope system at the 88-Inch Cyclotron of the Lawrence Berkeley National Laboratory. By using the Wilczynski binary transfer model, in combination with a standard evaporation model, they are able to reproduce the experimental results. This is a useful method for predicting the population of neutron-rich heavy nuclei formed in binary reactions involvingmore » beams of weakly bound nuclei and will be of use in future spectroscopic studies.« less

Development of the septal region in the rat. II. Morphogenesis in normal and x-irradiated embryos

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bayer, S.A.

1979-01-01

Morphogenesis of the septal region was examined in normal rat embryos from embryonic day (E) 10 to E22. The greater part of the septal region is postulated to form from two separate anlagen which can be clearly distinguished in the telencephalon by E13 and E14. One lies in the anterior ventromedial wall and presumably forms the nucleus of the diagonal band, medial, lateral, and triangular septal nuclei. The other lies in the posterior ventrolateral ridge and presumably forms the bed nuclei of the stria terminalis and the anterior commissure. On E15, the early differentiating cells in these anlagen fuse inmore » the same region where the anterior commissure will cross on E17. On E16 and E17, a prominent subependymal zone develops in the anterior septal region and presumably gives rise to the nucleus accumbens. A quantitative analysis was made of three cell zones (neuroepithelium, subependymal zone, differentiating cell zone) at coronal levels through the developing nucleus accumbens and the nucleus of the diagonal band (anterior level) and the medial and lateral septal nuclei (middle and posterior levels). To accurately locate regions of primitive mitotic and migratory cells within the zones at each level, the number of cells surviving a single exposure to 200 R x-rays in embryonic brains (E15 to E22) were compared with controls. Each zone responded differently to x-ray insult. The radiosensitivity of the neuroepithelium decreases significantly after E19; the subependymal zone is highly radiosensitive throughout; the differentiating cell zone is radioresistant throughout. The significance of these findings is discussed in the light of the autoradiographic determination of the time of formation of septal neurons.« less

Empirical moments of inertia of axially asymmetric nuclei

DOE PAGES

Allmond, J. M.; Wood, J. L.

2017-02-06

We extracted empirical moments of inertia, J1, J2, J3, of atomic nuclei with E(4more » $$+\\atop{1}$$)/E(2$$+\\atop{1}$$ ) > 2.7 from experimental 2$$+\\atop{g,y}$$, energies and electric quadrupole matrix elements, determined from multi- step Coulomb excitation data, and the results are compared to expectations based on rigid and irro- tational inertial flow. Only by having the signs of the E2 matrix elements, i.e., <2$$+\\atop{g}$$ ||M (E2)||2$$+\\atop{g}$$> and <0$$+\\atop{g}$$ ||M (E2)||2$$+\\atop{g}$$> < 2$$+\\atop{g}$$ ||M (E2)||2$$+\\atop{γ}$$> <2$$+\\atop{γ}$$ ||M (E2)||0$$+\\atop{g}$$> , can a unique solution to all three components of the inertia tensor of an asymmetric top be obtained. And while the absolute moments of inertia fall between the rigid and irrotational values as expected, the relative moments of inertia appear to be qualitatively consistent with the β 2 sin 2(γ ) dependence of the Bohr Hamiltonian which originates from a SO(5) in- variance. A better understanding of inertial flow is central to improving collective models, particularly hydrodynamic-based collective models. The results suggest that a better description of collective dynamics and inertial flow for atomic nuclei is needed. The inclusion of vorticity degrees of freedom may provide a path forward. This is our first report of empirical moments of inertia for all three axes and the results should challenge both collective and microscopic descriptions of inertial flow.« less

Deformable mirrors development program at ESO

NASA Astrophysics Data System (ADS)

Stroebele, Stefan; Vernet, Elise; Brinkmann, Martin; Jakob, Gerd; Lilley, Paul; Casali, Mark; Madec, Pierre-Yves; Kasper, Markus

2016-07-01

Over the last decade, adaptive optics has become essential in different fields of research including medicine and industrial applications. With this new need, the market of deformable mirrors has expanded a lot allowing new technologies and actuation principles to be developed. Several E-ELT instruments have identified the need for post focal deformable mirrors but with the increasing size of the telescopes the requirements on the deformable mirrors become more demanding. A simple scaling up of existing technologies from few hundred actuators to thousands of actuators will not be sufficient to satisfy the future needs of ESO. To bridge the gap between available deformable mirrors and the future needs for the E-ELT, ESO started a development program for deformable mirror technologies. The requirements and the path to get the deformable mirrors for post focal adaptive optics systems for the E-ELT is presented.

Systematics of nuclear deformation in large regions

NASA Astrophysics Data System (ADS)

Zhao, Y. M.; Arima, A.; Casten, R. F.

2001-06-01

In this paper we present the systematics of nuclear deformation for even-even, even-odd, odd-even, and doubly odd nuclei in four regions: the 50

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gupta, J. B.; Hamilton, J. H.

The change in the structure of the collective levels with spin angular momentum in atomic nuclei is often expressed in terms of the classical concepts of the kinematic and the dynamic moments of inertia varying with spin. For the well deformed even-even nuclei the kinematic moment of inertia increases with spin up to 10%-20%, at say I{sup {pi}} = 12{sup +}. However, for the shape transitional nuclei, or almost spherical nuclei, it increases with spin much faster. The pitfalls of using the rotor model form of kinematic moment of inertia in such cases are pointed out here. Alternative methods ofmore » extracting the nuclear structure information are explored. The important role of the ground state deformation is illustrated. The use of the power index formula for evaluating the effective moment of inertia, free from the assumption of the rotor model, is described.« less

Properties of r-process nuclei near N=82 shell closure

NASA Astrophysics Data System (ADS)

Farhan, A. R.; Sharma, M. M.

2004-10-01

We have studied properties of nuclei in r-process region near N=82 shell closure with the RMF calculations in a deformed basis using the force NL-SV1 that includes vector self-coupling of w meson. It is shown that nuclei above N=82 in several isotopic chains in the r-process region exhibit an onset of deformation beyond the drip line. Consequently, induced by the deformation these nuclei show an extra stability above the shell closure. This stability of nuclei is expected to contribute to the r-process nucleosynthesis of nuclei below the abundance peak at A ˜130. A comparison with the mass formulae shows that our microscopic calculations with NL-SV1 show a decrease of shell strength with increase in isospin. This is in contrast to the strong shell effects shown by FRDM and ETF-SI in going to the drip line. The stiffness of the shell structure with FRDM and ETF-SI is known to lead to a shortfall in the r-process abundances. This shortcoming of the above mass formulae has inspired an ad-hoc inclusion of shell quenching in the mass formula ETF-SI(Q) with a view to better reproduce the r-process abundances. In comparison, our model shows a decrease of the shell strength in going from the r-process path to the drip line. Therefore, this represents a natural behaviour as required by r-process abundances. It may, however, be confirmed in network chain calculations using inputs from our microscopic model.

α-cluster versus non-α-cluster decay of the excited compound nucleus Ce124* using the dynamical cluster-decay model

NASA Astrophysics Data System (ADS)

Kaur, Arshdeep; Chopra, Sahila; Gupta, Raj K.

2014-03-01

The dynamical cluster-decay model (DCM), an extended version of the preformed cluster model (PCM) for ground-state (T =0) decays, is applied to study the decay of the proton-rich compound nucleus Ce124* formed in the S32 + Mo92 reaction at an above-barrier beam energy of 150 MeV. Application of the statistical code pace4 to experimental data shows large deviations in all cases of proton clusters' (2p, 3p, and 4p) evaporation residue (ER) and the non-α nucleus Be6 intermediate mass fragment (IMF). Furthermore, the α-nucleus Be8 decay is not observed in this experiment (not even the upper limit is given). Using the DCM, with effects of deformations up to hexadecapole and "compact" orientations included, for the best-fitted cross sections of 2p and 3p ERs and of Li5 and Be6 IMFs, the relative cross section of Be8 is found to be more than that of Be6, possibly due to the α-nucleus structure of Be8. The same is shown to be true for C12 versus C10, i.e., α-nuclei clusters are populated strongly relative to non-α clusters, similar to what was predicted by one of us (R.K.G.) et al. [S. Kumar, D. Bir, and R. K. Gupta, Phys. Rev. C 51, 1762 (1995), 10.1103/PhysRevC.51.1762] for ground-state decays of such nuclei and the decay of Ba116* formed in the Ni58 + Ni58 reaction at various compound nucleus excitation energies [R. K. Gupta et al., J. Phys. G: Nucl. Part. Phys. 32, 345 (2006), 10.1088/0954-3899/32/3/009]. The only parameter of the DCM is the neck-length ΔR, related to the "barrier-lowering" parameter. The compound nucleus formation probability and "barrier-lowering/-modification" effects are analyzed, and the role of varying the deformations of Be6 and/or Be8 nuclei on relative cross sections is studied, since the measured deformations are not available. The ones used here are from relativistic mean-field calculations [β2(6Be )=-0.087 and β2(8Be)=-0.094]. Calculations are also presented for a beam energy of 140 MeV, supporting the above result.

Shape evolution of 72,74Kr with temperature in covariant density functional theory

NASA Astrophysics Data System (ADS)

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

Huntington’s disease (HD): Degeneration of select nuclei and widespread occurrence of neuronal nuclear and axonal inclusions in the brainstem

PubMed Central

Rüb, U; Hentschel, M; Stratmann, K; Brunt, ER; Heinsen, H; Seidel, K; Bouzrou, M; Auburger, G; Paulson, HL; Vonsattel, JP; Lange, HW; Korf, HW; den Dunnen, WF

2014-01-01

Huntington’s disease (HD) is a progressive polyglutamine disease that leads to a severe striatal and layer-specific neuronal loss in the cerebral neo-and allocortex. Since some of the clinical symptoms (e.g. oculomotor dysfunctions) suggested a degeneration of select brainstem nuclei we performed a systematic investigation of the brainstem of eight clinically diagnosed and genetically confirmed HD patients. This postmortem investigation revealed a consistent neuronal loss in the substantia nigra, pontine nuclei, reticulotegmental nucleus of the pons, superior and inferior olives, in the area of the excitatory burst neurons for horizontal saccades, raphe interpositus nucleus, and vestibular nuclei. Immunoreactive intranuclear neuronal inclusions were present in all degenerated and apparently spared brainstem nuclei, and immunoreactive axonal inclusions were observed in all brainstem fiber tracts of the HD patients. Degeneration of brainstem nuclei can account for a number of less well understood clinical HD symptoms (i.e. cerebellar, oculomotor and vestibular symptoms), while the formation of axonal aggregates may represent a crucial event in the cascades of pathological events leading to neurodegeneration in HD. PMID:24779419

Brueckner G -matrix approach for neutron-proton pairing correlations in the deformed BCS approach

NASA Astrophysics Data System (ADS)

Ha, Eunja; Cheoun, Myung-Ki; Šimkovic, F.

2015-10-01

Ground states of even-even Ge isotopes with mass number A =64 -76 have been studied in the deformed Bardeen-Cooper-Schrieffer (BCS) theory by taking neutron-proton (n p ) pairing correlations as well as neutron-neutron (n n ) and proton-proton (p p ) pairing correlations. The n p pairing has two different modes J =0 ,T =1 (isotriplet) and J =1 ,T =0 (isosinglet). In this work, the Brueckner G matrix, based on the CD-Bonn potential, has been exploited to reduce the ambiguity regarding nucleon-nucleon interactions inside nuclei compared to the results by a simple schematic phenomenological force. We found that the G matrix plays important roles to obtain reasonable descriptions of even-even nuclei compared to the schematic force. The n p pairing strength has been shown to have a clear correlation with quadrupole deformation parameter β2 for the isotopes, and affects the smearing of the Fermi surfaces of not only N =Z nuclei but also N ≠Z nuclei. In particular, the coexistence of the like particle (n n and p p ) and the n p pairing modes was found to become more salient by the G -matrix approach than by the schematic force approach.

Empirical p-n interactions, the synchronized filling of Nilsson orbitals, and emergent collectivity

NASA Astrophysics Data System (ADS)

Cakirli, R. B.

2014-09-01

The onset of collectivity and deformation, changes to the single particle energies and magic numbers and so on are strongly influenced by, for example, proton (p) and neutron (n) interactions inside atomic nuclei. Experimentally, using binding energies (or masses), one can extract an average p-n interaction between the last two protons and the last two neutrons, called δVpn. We have studied δVpn values using calculations of spatial overlaps between p and n Nilsson orbitals, considering different deformations, for the Z= 50-82, N= 82-126 shells, and comparison of these theoretical results with experimental δVpn values. Our results show that enhanced valence p-n interactions are closely correlated with the development of collectivity, shape changes, and the saturation of deformation in nuclei. We note that the difference of the Nilsson quantum numbers of the last filled Nilsson p and n orbitals, has a special relation, 0[110], in which they differ by only a single quantum in the z-direction, for those nuclei where δVpn is largest for each Z in medium mass and heavy nuclei. The synchronised filling of such orbital pairs correlates with the emergence of collectivity.

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

DOE PAGES

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

2015-09-10

Here, whether atomic nuclei can possess triaxial shapes at their ground states is still a subject of ongoing debate. According to theory, good prospects for low-spin triaxiality are in the neutron-rich Mo-Ru region. Recently, transition quadrupole moments in rotational bands of even-mass neutron-rich isotopes of molybdenum and ruthenium nuclei have been measured. The new data have provided a challenge for theoretical descriptions invoking stable triaxial deformations. The purpose of this study is to understand experimental data on rotational bands in the neutron-rich Mo-Ru region, we carried out theoretical analysis of moments of inertia, shapes, and transition quadrupole moments of neutron-richmore » even-even nuclei around 110Ru using self-consistent mean-field and shell model techniques. Methods: To describe yrast structures in Mo and Ru isotopes, we use nuclear density functional theory (DFT) with the optimized energy density functional UNEDF0. We also apply triaxial projected shell model (TPSM) to describe yrast and positive-parity, near-yrast band structures. As a result, our self-consistent DFT calculations predict triaxial ground-state deformations in 106,108Mo and 108,110,112Ru and reproduce the observed low-frequency behavior of moments of inertia. As the rotational frequency increases, a negative-gamma structure, associated with the aligned ν(h 11/2) 2 pair, becomes energetically favored. The computed transition quadrupole moments vary with angular momentum, which reflects deformation changes with rotation; those variations are consistent with experiment. The TPSM calculations explain the observed band structures assuming stable triaxial shapes. Lastly, the structure of neutron-rich even-even nuclei around Ru-110 is consistent with triaxial shape deformations. Our DFT and TPSM frameworks provide a consistent and complementary description of experimental data.« less

Isoscalar compression modes within fluid dynamic approach

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kolomietz, V. M.; Cyclotron Institute, Texas A and M University, College Station, Texas 77843-3366; Shlomo, S.

2000-06-01

We study the nuclear isoscalar monopole and dipole compression modes in nuclei within the fluid dynamic approach (FDA) with and without the effect of relaxation. For a wide region of the medium and heavy nuclei, the FDA predicts that the isoscalar giant monopole resonance (ISGMR) and the isoscalar giant dipole resonance (ISGDR) exhaust about 90% of the corresponding model-independent sum rules. In the case of neglecting the effect of relaxation, the FDA, when adjusted to reproduce the centroid energy E0 of the ISGMR, results with centroid energy E1 of the ISGDR which is in agreement with the predictions of themore » self-consistent Hartree-Fock random-phase approximation calculations and the scaling model but significantly larger than the experimental value. We also show that the FDA leads to the correct hydrodynamic limit for the ratio (E1/E0){sub FDA}. We find that the ratio (E1/E0){sub FDA} depends on the relaxation time and approaches the preliminary experimental value (E1/E0){sub exp}=1.5{+-}0.1 in a short relaxation time limit. (c) 2000 The American Physical Society.« less

The quadrupole moments of some even–even nuclei around the mass of A ~ 80: {sup 68−80}Ge on the neighborhood of {sup 76−84}Kr and {sup 76−84}Se isotopes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yoruk, Abdulkadir, E-mail: yorukabdulkadir@hotmail.com; Turkan, Nureddin, E-mail: nureddin.turkan@medeniyet.edu.tr

2016-09-15

We have carried out the calculation of the quadrupole moments Q(2{sub 1}{sup +}) and electromagnetic transition rates B(E2) of some levels within the framework of the interacting boson model for even-mass Ge nuclei. The presented predictions of the quadrupole moments and B(E2) ratios for Ge nuclei are compared with the results of some previous experimental and theoretical ones along with those of the neighboring Kr and Se isotopes and then it was seen that they agree well with the previous experimental and theoretical ones.

Violations of K-Conservation in 178Hf

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hayes, A. B.; Cline, D.; Wu, C. Y.

2006-03-13

Coulomb excitation of K{pi}=6+(t1/2=77 ns), 8-(t1/2=4.0 s) and 16+(t1/2=31 y) 178Hf isomers has led to the measurement of a set of E{lambda} matrix elements, coupling the isomer bands to the {gamma}- and ground state bands. The resulting matrix elements, derived using a coupled-channel semiclassical Coulomb excitation search code, have been used to probe the K-components in the wave functions and revealed the onset and saturation of K-mixing in low-K bands, whereas K-mixing is negligible in the high-K bands. The implications can be applied to other quadrupole-deformed nuclei. An upper limit on the Coulomb depopulation yield of the 16+ isomer wasmore » calculated based on the present set of matrix elements.« less

Interplay between proton-neutron pairing and deformation in self-conjugated medium mass nuclei

NASA Astrophysics Data System (ADS)

Gambacurta, Danilo; Lacroix, Denis

2016-05-01

We employ a model combining self-consistent mean-field and shell model techniques to study the competition between particle-like and proton-neutron pairing correlations in fp-shell even-even self-conjugate nuclei. Deformation effects are realistically and microscopically described. The resulting approach can give a precise description of pairing correlations and eventually treat the coexistence of different condensate formed of pairs with different total spin/ isospin. The standard BCS calculations are systematically compared with approaches including correlation effects beyond the independent quasi-particle picture. The competition between proton-neutron correlations in the isoscalar and isovector channels is also analyzed, as well as their dependence on the deformation properties.

A continuum theory of grain size evolution and damage

NASA Astrophysics Data System (ADS)

Ricard, Y.; Bercovici, D.

2009-01-01

Lithospheric shear localization, as occurs in the formation of tectonic plate boundaries, is often associated with diminished grain size (e.g., mylonites). Grain size reduction is typically attributed to dynamic recrystallization; however, theoretical models of shear localization arising from this hypothesis are problematic because (1) they require the simultaneous action of two creep mechanisms (diffusion and dislocation creep) that occur in different deformation regimes (i.e., in grain size stress space) and (2) the grain growth ("healing") laws employed by these models are derived from normal grain growth or coarsening theory, which are valid in the absence of deformation, although the shear localization setting itself requires deformation. Here we present a new first principles grained-continuum theory, which accounts for both coarsening and damage-induced grain size reduction in a monomineralic assemblage undergoing irrecoverable deformation. Damage per se is the generic process for generation of microcracks, defects, dislocations (including recrystallization), subgrains, nuclei, and cataclastic breakdown of grains. The theory contains coupled macroscopic continuum mechanical and grain-scale statistical components. The continuum level of the theory considers standard mass, momentum, and energy conservation, as well as entropy production, on a statistically averaged grained continuum. The grain-scale element of the theory describes both the evolution of the grain size distribution and mechanisms for both continuous grain growth and discontinuous grain fracture and coalescence. The continuous and discontinuous processes of grain size variation are prescribed by nonequilibrium thermodynamics (in particular, the treatment of entropy production provides the phenomenological laws for grain growth and reduction); grain size evolution thus incorporates the free energy differences between grains, including both grain boundary surface energy (which controls coarsening) and the contribution of deformational work to these free energies (which controls damage). In the absence of deformation, only two mechanisms that increase the average grain size are allowed by the second law of thermodynamics. One mechanism, involving continuous diffusive mass transport from small to large grains, captures the essential components of normal grain growth theories of Lifshitz-Slyosov and Hillert. The second mechanism involves the aggregation of grains and is described using a Smoluchovski formalism. With the inclusion of deformational work and damage, the theory predicts two mechanisms for which the thermodynamic requirement of entropy positivity always forces large grains to shrink and small ones to grow. The first such damage-driven mechanism involving continuous mass transfer from large to small grains tends to homogenize the distribution of grain size toward its initial mean grain size. The second damage mechanism favors the creation of small grains by discontinuous division of larger grains and reduces the mean grain size with time. When considered separately, most of these mechanisms allow for self-similar grain size distributions whose scales (i.e., statistical moments such as the mean, variance, and skewness) can all be described by a single grain scale, such as the mean or maximum. However, the combination of mechanisms, e.g., one that captures the competition between continuous coarsening and mean grain size reduction by breakage, does not generally permit a self-similar solution for the grain size distribution, which contradicts the classic assumption that grain growth laws allowing for both coarsening and recrystallization can be treated with a single grain scale such as the mean size.

Double-β decay matrix elements from lattice quantum chromodynamics

NASA Astrophysics Data System (ADS)

Tiburzi, Brian C.; Wagman, Michael L.; Winter, Frank; Chang, Emmanuel; Davoudi, Zohreh; Detmold, William; Orginos, Kostas; Savage, Martin J.; Shanahan, Phiala E.; Nplqcd Collaboration

2017-09-01

A lattice quantum chromodynamics (LQCD) calculation of the nuclear matrix element relevant to the n n →p p e e ν¯eν¯e transition is described in detail, expanding on the results presented in Ref. [P. E. Shanahan et al., Phys. Rev. Lett. 119, 062003 (2017), 10.1103/PhysRevLett.119.062003]. This matrix element, which involves two insertions of the weak axial current, is an important input for phenomenological determinations of double-β decay rates of nuclei. From this exploratory study, performed using unphysical values of the quark masses, the long-distance deuteron-pole contribution to the matrix element is separated from shorter-distance hadronic contributions. This polarizability, which is only accessible in double-weak processes, cannot be constrained from single-β decay of nuclei, and is found to be smaller than the long-distance contributions in this calculation, but non-negligible. In this work, technical aspects of the LQCD calculations, and of the relevant formalism in the pionless effective field theory, are described. Further calculations of the isotensor axial polarizability, in particular near and at the physical values of the light-quark masses, are required for precise determinations of both two-neutrino and neutrinoless double-β decay rates in heavy nuclei.

Transneuronal pathways to the vestibulocerebellum

NASA Technical Reports Server (NTRS)

Kaufman, G. D.; Mustari, M. J.; Miselis, R. R.; Perachio, A. A.

1996-01-01

The alpha-herpes virus (pseudorabies, PRV) was used to observe central nervous system (CNS) pathways associated with the vestibulocerebellar system. Retrograde transneuronal migration of alpha-herpes virions from specific lobules of the gerbil and rat vestibulo-cerebellar cortex was detected immunohistochemically. Using a time series analysis, progression of infection along polyneuronal cerebellar afferent pathways was examined. Pressure injections of > 20 nanoliters of a 10(8) plaque forming units (pfu) per ml solution of virus were sufficient to initiate an infectious locus which resulted in labeled neurons in the inferior olivary subnuclei, vestibular nuclei, and their afferent cell groups in a progressive temporal fashion and in growing complexity with increasing incubation time. We show that climbing fibers and some other cerebellar afferent fibers transported the virus retrogradely from the cerebellum within 24 hours. One to three days after cerebellar infection discrete cell groups were labeled and appropriate laterality within crossed projections was preserved. Subsequent nuclei labeled with PRV after infection of the flocculus/paraflocculus, or nodulus/uvula, included the following: vestibular (e.g., z) and inferior olivary nuclei (e.g., dorsal cap), accessory oculomotor (e.g., Darkschewitsch n.) and accessory optic related nuclei, (e.g., the nucleus of the optic tract, and the medial terminal nucleus); noradrenergic, raphe, and reticular cell groups (e.g., locus coeruleus, dorsal raphe, raphe pontis, and the lateral reticular tract); other vestibulocerebellum sites, the periaqueductal gray, substantia nigra, hippocampus, thalamus and hypothalamus, amygdala, septal nuclei, and the frontal, cingulate, entorhinal, perirhinal, and insular cortices. However, there were differences in the resulting labeling between infection in either region. Double-labeling experiments revealed that vestibular efferent neurons are located adjacent to, but are not included among, flocculus-projecting supragenual neurons. PRV transport from the vestibular labyrinth and cervical muscles also resulted in CNS infections. Virus propagation in situ provides specific connectivity information based on the functional transport across synapses. The findings support and extend anatomical data regarding vestibulo-olivo-cerebellar pathways.

Influence of Axisymmetrically Deformed Explosions in Type II Supernovae on the Reproduction of the Solar System Abundances

NASA Astrophysics Data System (ADS)

Nagataki, Shigehiro

1999-01-01

We have tried to reproduce the solar system abundances using the nucleosynthesis products of Type Ia and Type II supernovae. In particular, we examined the effects of axisymmetrically deformed explosions in Type II supernovae. 44Ca and 47,48Ti are enhanced considerably in axisymmetrically deformed explosion models because of the active alpha-rich freezeout. The enhancement of nuclei around A=45 is a welcome result since it solves the problem of the nuclei shortage. Moreover, 59Co, 63,65Cu, and 66Zn are enhanced enough to reproduce the solar system abundances. The enhancement of Cu and Zn means the possibility that these nuclei, which have been said to be produced by the slow process, can be synthesized fairly well during the explosive nucleosynthesis. To discuss their origin quantitatively, the position of the mass cut is a very important parameter that is very difficult to determine numerically at present. We also stress that an axisymmetrically deformed explosion of Type II supernovae of the degree that is considered in this analysis is not excluded by the results of calculations of explosive nucleosynthesis, that is, the nucleosynthesis products are not extremely disturbed and the solar system abundances can be reproduced fairly well by the axisymmetrically deformed explosion models. This conclusion will be good for the theory of core collapse including the rotation of an iron core, magnetic field, and axisymmetrically modified neutrino radiation from a rotating protoneutron star, which possibly can cause an axisymmetrically deformed explosion.

Review of metastable states in heavy nuclei

DOE PAGES

Dracoulis, G. D.; Walker, P. M.; Kondev, F. G.

2016-05-31

Here, the structure of nuclear isomeric states is reviewed in the context of their role in contemporary nuclear physics research. Emphasis is given to high-spin isomers in heavy nuclei, with A ≳ 150. The possibility to exploit isomers to study some of the most exotic nuclei is a recurring theme. In spherical nuclei, the role of octupole collectivity is discussed in detail, while in deformed nuclei the limitations of the K quantum number are addressed. Isomer targets and isomer beams are considered, along with applications related to energy storage, astrophysics, medicine, and experimental advances.

In-vivo cell tracking to quantify endothelial cell migration during zebrafish angiogenesis

NASA Astrophysics Data System (ADS)

Menon, Prahlad G.; Rochon, Elizabeth R.; Roman, Beth L.

2016-03-01

The mechanism of endothelial cell migration as individual cells or collectively while remaining an integral component of a functional blood vessel has not been well characterized. In this study, our overarching goal is to define an image processing workflow to facilitate quantification of how endothelial cells within the first aortic arch and are proximal to the zebrafish heart behave in response to the onset of flow (i.e. onset of heart beating). Endothelial cell imaging was conducted at this developmental time-point i.e. ~24-28 hours post fertilization (hpf) when flow first begins, using 3D+time two-photon confocal microscopy of a live, wild-type, transgenic, zebrafish expressing green fluorescent protein (GFP) in endothelial cell nuclei. An image processing pipeline comprised of image signal enhancement, median filtering for speckle noise reduction, automated identification of the nuclei positions, extraction of the relative movement of nuclei between consecutive time instances, and finally tracking of nuclei, was designed for achieving the tracking of endothelial cell nuclei and the identification of their movement towards or away from the heart. Pilot results lead to a hypothesis that upon the onset of heart beat and blood flow, endothelial cells migrate collectively towards the heart (by 21.51+/-10.35 μm) in opposition to blood flow (i.e. subtending 142.170+/-21.170 with the flow direction).

Deformation potentials for band-to-band tunneling in silicon and germanium from first principles

NASA Astrophysics Data System (ADS)

Vandenberghe, William G.; Fischetti, Massimo V.

2015-01-01

The deformation potentials for phonon-assisted band-to-band tunneling (BTBT) in silicon and germanium are calculated using a plane-wave density functional theory code. Using hybrid functionals, we obtain: DTA = 4.1 × 108 eV/cm, DTO = 1.2 × 109 eV/cm, and DLO = 2.2 × 109 eV/cm for BTBT in silicon and DTA = 7.8 × 108 eV/cm and DLO = 1.3 × 109 eV/cm for BTBT in germanium. These values agree with experimentally measured values and we explain why in diodes, the TA/TO phonon-assisted BTBT dominates over LO phonon-assisted BTBT despite the larger deformation potential for the latter. We also explain why LO phonon-assisted BTBT can nevertheless dominate in many practical applications.

Study of yrast bands and electromagnetic properties in neutron-rich 114-128Cd isotopes

NASA Astrophysics Data System (ADS)

Chaudhary, Ritu; Pandit, Rakesh K.; Devi, Rani; Khosa, S. K.

2018-02-01

The projected shell model framework has been employed to carry out a systematic study on the deformation systematics of E (21+) and E (41+) / E (21+) values, BCS subshell occupation numbers, yrast spectra, backbending phenomena and electromagnetic quantities in 114-128Cd isotopes. Present calculations reproduce the observed systematics of the E (21+), R42 and B (E 2 ;2+ →0+) values for 114-128Cd isotopic mass chain and give the evidence that deformation increases as one moves from 114Cd to 118Cd, thereafter it decreases up to 126Cd. This in turn confirms 118Cd to be the most deformed nucleus in this set of isotopic mass chain. The emergence of backbending, decrease in B (E 2) values and change in g-factors in all these isotopes are intimately related to the crossing of g-band by 2-qp bands.

Electrical percolation threshold of magnetostrictive inclusions in a piezoelectric matrix under simulated sintering conditions

NASA Astrophysics Data System (ADS)

Bedard, Antoine Joseph; Barbero, Ever J.

2018-03-01

Magnetoelectric (ME) composites can be produced by embedding magnetostrictive H particles in a piezoelectric E matrix derived from a piezoelectric powder precursor. Previously, using a bi-disperse hard-shell model (Barbero and Bedard in Comput Part Mech, 2018. https://doi.org/10.1007/s40571-017-0165-4), it has been shown that the electrical percolation threshold of the conductive H phase can be increased by decreasing the piezoelectric E particle size, relative to the H phase particle size, and by increasing short-range affinity between the E and H particles. This study builds on our previous study by exploring what happens during sintering of the ME composite when either the H or E particles undergo deformation. It was found that deformation of the H particles reduces the percolation threshold, and that deformation of E particles increases inter-phase H-E mechanical coupling, thus contributing to enhancing of ME coupling.

Coulomb Excitation of n-rich nuclei along the N = 50 shell closure

NASA Astrophysics Data System (ADS)

Padilla-Rodal, E.; Galindo-Uribarri, A.; Batchelder, J. C.; Beene, J. R.; Bingham, C.; Brown, B. A.; Lagergren, K. B.; Mueller, P. E.; Radford, D. C.; Stracener, D. W.; Urrego-Blanco, J. P.; Varner, R. L.; Yu, C.-H.

2008-04-01

Recently, we have been investigating characteristics of nuclear states around the neutron-rich mass A=80 region [1]. Using the Radioactive Ion Beams (RIBs) produced at HRIBF, we have successfully measured the B(E2) values for ^78,80,82Ge , using Coulomb excitation in inverse kinematics. For the germanium isotopes, these data allow a study of the systematic trend between the subshell N= 40 and the N=50 shell. Using the same technique, we have measured the B(E2) value of various nuclei along the N=50 shell including the radioactive nucleus ^84Se. This value together with our previously measured ^82Ge, and the recent result on ^80Zn from ISOLDE [2] are providing basic experimental information needed for a better understanding of the neutron-rich nuclei around A˜80. We report the new results and compare with shell model calculations. [1] E. Padilla-Rodal et al., Phys. Rev. Lett. 94 (2005) 122501. [2] J. Van de Walle et al., Phys. Rev. Lett. 99 (2007) 142501.

DAMQT: A package for the analysis of electron density in molecules

NASA Astrophysics Data System (ADS)

López, Rafael; Rico, Jaime Fernández; Ramírez, Guillermo; Ema, Ignacio; Zorrilla, David

2009-09-01

DAMQT is a package for the analysis of the electron density in molecules and the fast computation of the density, density deformations, electrostatic potential and field, and Hellmann-Feynman forces. The method is based on the partition of the electron density into atomic fragments by means of a least deformation criterion. Each atomic fragment of the density is expanded in regular spherical harmonics times radial factors, which are piecewise represented in terms of analytical functions. This representation is used for the fast evaluation of the electrostatic potential and field generated by the electron density and nuclei, as well as for the computation of the Hellmann-Feynman forces on the nuclei. An analysis of the atomic and molecular deformations of the density can be also carried out, yielding a picture that connects with several concepts of the empirical structural chemistry. Program summaryProgram title: DAMQT1.0 Catalogue identifier: AEDL_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEDL_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: GPLv3 No. of lines in distributed program, including test data, etc.: 278 356 No. of bytes in distributed program, including test data, etc.: 31 065 317 Distribution format: tar.gz Programming language: Fortran90 and C++ Computer: Any Operating system: Linux, Windows (Xp, Vista) RAM: 190 Mbytes Classification: 16.1 External routines: Trolltech's Qt (4.3 or higher) ( http://www.qtsoftware.com/products), OpenGL (1.1 or higher) ( http://www.opengl.org/), GLUT 3.7 ( http://www.opengl.org/resources/libraries/glut/). Nature of problem: Analysis of the molecular electron density and density deformations, including fast evaluation of electrostatic potential, electric field and Hellmann-Feynman forces on nuclei. Solution method: The method of Deformed Atoms in Molecules, reported elsewhere [1], is used for partitioning the molecular electron density into atomic fragments, which are further expanded in spherical harmonics times radial factors. The partition is used for defining molecular density deformations and for the fast calculation of several properties associated to density. Restrictions: The current version is limited to 120 atoms, 2000 contracted functions, and l=5 in basis functions. Density must come from a LCAO calculation (any level) with spherical (not Cartesian) Gaussian functions. Unusual features: The program contains an OPEN statement to binary files (stream) in file GOPENMOL.F90. This statement has not a standard syntax in Fortran 90. Two possibilities are considered in conditional compilation: Intel's ifort and Fortran2003 standard. This latter is applied to compilers other than ifort (gfortran uses this one, for instance). Additional comments: The distribution file for this program is over 30 Mbytes and therefore is not delivered directly when download or e-mail is requested. Instead a html file giving details of how the program can be obtained is sent. Running time: Largely dependent on the system size and the module run (from fractions of a second to hours). References: [1] J. Fernández Rico, R. López, I. Ema, G. Ramírez, J. Mol. Struct. (Theochem) 727 (2005) 115.

Spin excitations in the deformed nuclei 154Sm, 158Gd and 168Er

NASA Astrophysics Data System (ADS)

Frekers, D.; Wörtche, H. J.; Richter, A.; Abegg, R.; Azuma, R. E.; Celler, A.; Chan, C.; Drake, T. E.; Helmer, R.; Jackson, K. P.; King, J. D.; Miller, C. A.; Schubank, R.; Vetterli, M. C.; Yen, S.

1990-07-01

An intermediate energy proton scattering experiment has been performed to probe spin excitation in the deformed rare earth nuclei 154Sm, 158Gd and 168Er for energies up to 12 MeV. A concentration of spin M1 strength is observed between 6 and 10MeV with a total strength of about 11 μN2 independent of the nucleus. The strength function shows two distinct structures separated by about 2.5 MeV and each having a width of about 2 MeV.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dracoulis, G. D.; Walker, P. M.; Kondev, F. G.

Here, the structure of nuclear isomeric states is reviewed in the context of their role in contemporary nuclear physics research. Emphasis is given to high-spin isomers in heavy nuclei, with A ≳ 150. The possibility to exploit isomers to study some of the most exotic nuclei is a recurring theme. In spherical nuclei, the role of octupole collectivity is discussed in detail, while in deformed nuclei the limitations of the K quantum number are addressed. Isomer targets and isomer beams are considered, along with applications related to energy storage, astrophysics, medicine, and experimental advances.

Weak e+e- lines from internal pair conversion observed in collisions of 238U with heavy nuclei

NASA Astrophysics Data System (ADS)

Heinz, S.; Berdermann, E.; Heine, F.; Joeres, O.; Kienle, P.; Koenig, I.; Koenig, W.; Kozhuharov, C.; Leinberger, U.; Rhein, M.; Schröter, A.; Tsertos, H.

1998-01-01

We present the results of a Doppler-shift correction to the measured e+e- sum-energy spectra obtained from e+e- coincidence measurements in 238U +206Pb and 238U +181Ta collisions at beam energies close to the Coulomb barrier, using an improved experimental setup at the double-Orange spectrometer of GSI. Internal-Pair-Conversion (IPC) e+e- pairs from discrete nuclear transitions of a moving emitter have been observed following Coulomb excitation of the 1.844 MeV (E1) transition in 206Pb and neutron transfer to the 1.770 MeV (M1) transition in 207Pb. In the collision system 238U +181Ta, IPC transitions were observed from the Ta-like as well as from the U-like nuclei. In all systems the Doppler-shift corrected e+e- sum-energy spectra show weak lines at the energies expected from the corresponding γ ray spectra with cross sections being consistent with the measured excitation cross sections of the γ lines and the theoretically predicted IPC coefficients. No other than IPC e+e- sum-energy lines were found in the measured spectra. The transfer cross sections show a strong dependence on the distance of closest approach (Rmin), thus signaling also a strong dependence on the bombarding energy close to the Coulomb barrier.

Proxy-SU(3) symmetry in heavy deformed nuclei

NASA Astrophysics Data System (ADS)

Bonatsos, Dennis; Assimakis, I. E.; Minkov, N.; Martinou, Andriana; Cakirli, R. B.; Casten, R. F.; Blaum, K.

2017-06-01

Background: Microscopic calculations of heavy nuclei face considerable difficulties due to the sizes of the matrices that need to be solved. Various approximation schemes have been invoked, for example by truncating the spaces, imposing seniority limits, or appealing to various symmetry schemes such as pseudo-SU(3). This paper proposes a new symmetry scheme also based on SU(3). This proxy-SU(3) can be applied to well-deformed nuclei, is simple to use, and can yield analytic predictions. Purpose: To present the new scheme and its microscopic motivation, and to test it using a Nilsson model calculation with the original shell model orbits and with the new proxy set. Method: We invoke an approximate, analytic, treatment of the Nilsson model, that allows the above vetting and yet is also transparent in understanding the approximations involved in the new proxy-SU(3). Results: It is found that the new scheme yields a Nilsson diagram for well-deformed nuclei that is very close to the original Nilsson diagram. The specific levels of approximation in the new scheme are also shown, for each major shell. Conclusions: The new proxy-SU(3) scheme is a good approximation to the full set of orbits in a major shell. Being able to replace a complex shell model calculation with a symmetry-based description now opens up the possibility to predict many properties of nuclei analytically and often in a parameter-free way. The new scheme works best for heavier nuclei, precisely where full microscopic calculations are most challenged. Some cases in which the new scheme can be used, often analytically, to make specific predictions, are shown in a subsequent paper.

Control of cell nucleus shapes via micropillar patterns.

PubMed

Pan, Zhen; Yan, Ce; Peng, Rong; Zhao, Yingchun; He, Yao; Ding, Jiandong

2012-02-01

We herein report a material technique to control the shapes of cell nuclei by the design of the microtopography of substrates to which the cells adhere. Poly(D,L-lactide-co-glycolide) (PLGA) micropillars or micropits of a series of height or depth were fabricated, and some surprising self deformation of the nuclei of bone marrow stromal cells (BMSCs) was found in the case of micropillars with a sufficient height. Despite severe nucleus deformation, BMSCs kept the ability of proliferation and differentiation. We further demonstrated that the shapes of cell nuclei could be regulated by the appropriate micropillar patterns. Besides circular and elliptoid shapes, some unusual nucleus shapes of BMSCs have been achieved, such as square, cross, dumbbell, and asymmetric sphere-protrusion. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

Simulation of Texture Evolution during Uniaxial Deformation of Commercially Pure Titanium

NASA Astrophysics Data System (ADS)

Bishoyi, B.; Debta, M. K.; Yadav, S. K.; Sabat, R. K.; Sahoo, S. K.

2018-03-01

The evolution of texture in commercially pure (CP) titanium during uniaxial tension and compression through VPSC (Visco-plastic self-consistent) simulation is reported in the present study. CP-titanium was subjected to both uniaxial tension and compression upto 35% deformation. During uniaxial tension, tensile twin of \\{10\\bar{1}2\\}\\unicode{x003C;}\\bar{1}011\\unicode{x003E;} type and compressive twin of \\{11\\bar{2}2\\}\\unicode{x003C;}11\\bar{2}\\bar{3}\\unicode{x003E;} type were observed in the samples. However, only tensile twin of \\{10\\bar{1}2\\}\\unicode{x003C;}\\bar{1}011\\unicode{x003E;} type and compressive twin of type was observed in the samples during uniaxial compression. Volume fractions of the twins were increased linearly as a function of percentage deformation during uniaxial tension. Whereas, during uniaxial compression the twinning volume fraction was increased up to 20% deformation and then decreased rapidly on further increasing the percentage deformation. During uniaxial tension, the general t-type textures were observed in the samples irrespective of the percentage deformation. The initial non-basal texture was oriented to split basal texture during uniaxial compression of the sample. VPSC formulation was used for simulating the texture development in the material. Different hardening parameters were estimated through correlating the simulated stress-strain curve with the experimental stress-strain data. It was observed that, prismatic slip \\{10\\bar{1}0\\}\\unicode{x003C;}11\\bar{2}0\\unicode{x003E;} operated as the primary deformation mode during uniaxial tension whereas basal slip \\{0001\\}\\unicode{x003C;}11\\bar{2}0\\unicode{x003E;} acquired the leading role during deformation through uniaxial compression. It was also revealed that active deformation modes were fully depending on percentage deformation, loading direction, and orientation of grains.

The Heavy Nuclei eXplorer (HNX) Small Explorer Mission

NASA Astrophysics Data System (ADS)

Mitchell, John; Binns, W. Robert; Hams, Thomas; Israel, Martin; Krizmanic, John; Link, Jason; Rauch, Brian; Sakai, Kenichi; Sasaki, Makoto; Westphal, Andrew; Wiedenbeck, Mark; Heavy Nuclei eXplorer Collaboration

2015-04-01

The Heavy Nuclei eXplorer (HNX) will investigate the nature of the reservoirs of nuclei at the cosmic-ray sources, the mechanisms by which nuclei are removed from the reservoirs and injected into the cosmic accelerators, and the acceleration mechanism. HNX will use two large high-precision instruments, the Extremely-heavy Cosmic-ray Composition Observer (ECCO) and the Cosmic-ray Trans-Iron Galactic Element Recorder (CosmicTIGER), flying in the SpaceX DragonLab, to measure, for the first time, the abundance of every individual element in the periodic table from carbon through the actinides, providing the first measurement of many of these elements. HNX will measure several thousand ultra-heavy galactic cosmic ray (UHGCR) nuclei Z >= 30, including about 50 actinides, and will: determine whether GCRs are accelerated from new or old material, and find their age; measure the mix of nucleosynthesis processes responsible for the UHGCRs; determine how UHGCR elements are selected for acceleration, and measure the mean integrated pathlength traversed by UHGCRs before observation. The scientific motivation and instrument complement of HNX will be discussed.

Surprises in Studies of Superdeformation in the Mass A ~80 Region.

NASA Astrophysics Data System (ADS)

Lafosse, Dennis R.

1996-11-01

The study of superdeformation (SD) in the light nuclei around A ~80 only recently began with the advent of the third generation of γ-ray detector arrays. The uc(gammasphere) array in conjunction with the Washington University uc(microball) have offered unprecedented sensitivity in this mass region, which has been applied effectively to the study of these nuclei. Whereas there were no SD bands known in this light mass region only two years ago, over 20 bands in 9 nuclei have recently been discovered. Interesting systematic properties are beginning to emerge. For example, the measured deformations of the yrast SD bands in _38Sr nuclei show a large dependence on neutron number; the deformation of the yrast band in ^80Sr was determined to be surprisingly small, and comparable to that of the yrast normal-deformed states! Individual nuclei have also revealed surprising features. For example, an SD band in ^81Sr was found to decay out to another (SD?) state, but then to decay back into the SD band. A very interesting result was found in ^87Nb. Two SD bands in ^87Nb have been found to mutually interact with each other, and resulting cross transitions between the two bands have been observed. This interaction has been traced to a crossing of two neutron orbitals. Finally, future surprises may be in store. SD bands in this mass region are observed to extremely high rotational frequencies, often approaching hbarω=1.5 MeV. The extreme Coriolis force then brings the N=6 i_13/2 orbital down to the Fermi surface. Thus, SD bands having deformations approaching β_2=0.8 may be observed as a result of the high deformation driving property of these ``superintruder'' orbitals. The first hint of such states may have already been discovered in ^87Nb. One of the SD bands in this nucleus reveals a crossing which is likely due to the occupation of the i_13/2 orbital at the highest frequencies. The work to be presented is the result of an ongoing collaboration between Washington University, Oak Ridge National Laboratory, the University of Pittsburgh and Florida State University.

Development of the precerebellar nuclei in the rat: IV. The anterior precerebellar extramural migratory stream and the nucleus reticularis tegmenti pontis and the basal pontine gray.

PubMed

Altman, J; Bayer, S A

1987-03-22

Sequential thymidine radiograms from rats injected on days E16, E17, E18, and E19 and killed 2 hours after injection and at daily intervals up to day E22 were used to establish the site of origin, migratory route, and settling patterns of neurons of the nucleus reticularis tegmenti pontis and basal pontine gray. The nucleus reticularis tegmenti pontis neurons, which are produced predominantly on days E15 and E16, derive from the primary precerebellar neuroepithelium. These cells, unlike those of the lateral reticular and external cuneate nuclei, take an anteroventral subpial route, forming the anterior precerebellar extramural migratory stream. This migratory stream reaches the anterior pole of the pons by day E18. In rats injected on day E16 and killed on day E18 some of the cells that reach the pons are unlabeled, indicating that they represent the early component of neurons generated on day E15. The cells labeled on day E16 begin to settle in the pons on day E19, 3 days after their production. These cells, migrating in an orderly temporal sequence, form a posterodorsal-to-anteroventral gradient in the nucleus reticularis tegmenti pontis. Unlike the neurons of all the other precerebellar nuclei, the basal pontine gray neurons derive from the secondary precerebellar neuroepithelium. The secondary precerebellar neuroepithelium forms on day E16 as an outgrowth of the primary precerebellar neuroepithelium, and it remains mitotically active through day E19, spanning the entire period of basal pontine gray neurogenesis. The secondary precerebellar neuroepithelium is surrounded by a horizontal layer of postmitotic cells, representing the head-waters of the anterior precerebellar extramural migratory stream. In rats injected on day E18 and killed on day E19 the cells are labeled in the proximal half of the stream around the medulla but those closer to the pons are unlabeled, indicating an orderly sequence of migration. In rats injected on day E18 and killed on day E20 the labeled cells reach the pole of the pons. In the basal pontine gray the sequentially generated neurons settle in a precise order. The neurons generated on day E16 form a small core posteriorly and the neurons generated on days E17, E18, and E19 form regular concentric rings around the core in an inside-out sequence.

The study of the physics of cometary nuclei

NASA Technical Reports Server (NTRS)

Whipple, F. L.

1983-01-01

On the basis of the icy conglometate model of cometary nuclei various observations demonstrate the spotted nature of many or most nuclei, i.e., regions of unusual activity, either high or low. Rotation periods, spin axes and even precession of the axes have been determined. Narrow dust jets near the nuclei of some bright comets require that small sources be embedded in larger active areas. Certain evidence suggests that very dusty areas and very dusty comets may be less active, respectively, than surrounding areas or other comets.

Nuclear structure studies with gamma-ray beams

DOE PAGES

Tonchev, Anton; Bhatia, Chitra; Kelley, John; ...

2015-05-28

In stable and weakly bound neutron-rich nuclei, a resonance-like concentration of dipole states has been observed for excitation energies below the neutron-separation energy. This clustering of strong dipole states has been named the Pygmy Dipole Resonance (PDR) in contrast to the Giant Dipole Resonance (GDR) that dominates the E1 response. Understanding the PDR is presently of great interest in nuclear structure and nuclear astrophysics. High-sensitivity studies of E1 and M1 transitions in closed-shell nuclei using monoenergetic and 100% linearly-polarized photon beams are presented.

Nuclear Structure Studies with Gamma-Ray Beams

NASA Astrophysics Data System (ADS)

Tonchev, Anton; Bhatia, Chitra; Kelley, John; Raut, Rajarshi; Rusev, Gencho; Tornow, Werner; Tsoneva, Nadia

2015-05-01

In stable and weakly bound neutron-rich nuclei, a resonance-like concentration of dipole states has been observed for excitation energies below the neutron-separation energy. This clustering of strong dipole states has been named the Pygmy Dipole Resonance (PDR) in contrast to the Giant Dipole Resonance (GDR) that dominates the E1 response. Understanding the PDR is presently of great interest in nuclear structure and nuclear astrophysics. High-sensitivity studies of E1 and M1 transitions in closed-shell nuclei using monoenergetic and 100% linearly-polarized photon beams are presented.

Pondermotive acceleration of charged particles along the relativistic jets of an accreting blackhole

NASA Astrophysics Data System (ADS)

Ebisuzaki, T.; Tajima, T.

2014-05-01

Accreting blackholes such as miniquasars and active galactic nuclei can contribute to the highest energy components of intra- (˜1015 eV) galactic and extra-galactic components (˜1020 eV) of cosmic rays. Alfven wave pulses which are excited in the accretion disk around blackholes propagate in relativistic jets. Because of their highly non-linear nature of the waves, charged particles (protons, ions, and electrons) can be accelerated to high energies in relativistic jets in accreting blackhole systems, the central engine of miniquasars and active galactic nuclei.

Statistical error propagation in ab initio no-core full configuration calculations of light nuclei

DOE PAGES

Navarro Pérez, R.; Amaro, J. E.; Ruiz Arriola, E.; ...

2015-12-28

We propagate the statistical uncertainty of experimental N N scattering data into the binding energy of 3H and 4He. Here, we also study the sensitivity of the magnetic moment and proton radius of the 3 H to changes in the N N interaction. The calculations are made with the no-core full configuration method in a sufficiently large harmonic oscillator basis. For those light nuclei we obtain Δ E stat (3H) = 0.015 MeV and Δ E stat ( 4He) = 0.055 MeV .

Nuclear exoticism

DOE Office of Scientific and Technical Information (OSTI.GOV)

Penionzhkevich, Yu. E., E-mail: pyuer@mail.ru

2016-07-15

Extreme states of nuclearmatter (such that feature high spins, large deformations, high density and temperature, or a large excess of neutrons and protons) play an important role in studying fundamental properties of nuclei and are helpful in solving the problem of constructing the equation of state for nuclear matter. The synthesis of neutron-rich nuclei near the nucleon drip lines and investigation of their properties permit drawing conclusions about the positions of these boundaries and deducing information about unusual states of such nuclei and about their decays. At the present time, experimental investigations along these lines can only be performed viamore » the cooperation of leading research centers that possess powerful heavy-ion accelerators, such as the Large Hadron Collider (LHC) at CERN and the heavy-ion cyclotrons at the Joint Institute for Nuclear Research (JINR, Dubna), where respective experiments are being conducted by physicists from about 20 JINR member countries. The present article gives a survey of the most recent results in the realms of super neutron-rich nuclei. Implications of the change in the structure of such nuclei near the nucleon drip lines are discussed. Information about the results obtained by measuring the masses (binding energies) of exotic nuclei, the nucleon-distribution radii (neutron halo) and momentum distributions in them, and their deformations and quantum properties is presented. It is shown that the properties of nuclei lying near the stability boundaries differ strongly from the properties of other nuclei. The problem of the stability of nuclei that is associated with the magic numbers of 20 and 28 is discussed along with the effect of new magic numbers.« less

Interacting Boson Model and nucleons

NASA Astrophysics Data System (ADS)

Otsuka, Takaharu

2012-10-01

An overview on the recent development of the microscopic derivation of the Interacting Boson Model is presented with some remarks not found elsewhere. The OAI mapping is reviewed very briefly, including the basic correspondence from nucleon-pair to boson. The new fermionboson mapping method is introduced, where intrinsic states of nucleons and bosons for a wide variation of shapes play an important role. Nucleon intrinsic states are obtained from mean field models, which is Skyrme model in examples to be shown. This method generates IBM-2 Hamiltonian which can describe and predict various situations of quadrupole collective states, including U(5), SU(3), O(6) and E(5) limits. The method is extended so that rotational response (cranking) can be handled, which enables us to describe rotational bands of strongly deformed nuclei. Thus, we have obtained a unified framework for the microscopic derivation of the IBM covering all known situations of quadrupole collectivity at low energy.

Nuclear quantum shape-phase transitions in odd-mass systems

NASA Astrophysics Data System (ADS)

Quan, S.; Li, Z. P.; Vretenar, D.; Meng, J.

2018-03-01

Microscopic signatures of nuclear ground-state shape-phase transitions in odd-mass Eu isotopes are explored starting from excitation spectra and collective wave functions obtained by diagonalization of a core-quasiparticle coupling Hamiltonian based on energy density functionals. As functions of the physical control parameter—the number of nucleons—theoretical low-energy spectra, two-neutron separation energies, charge isotope shifts, spectroscopic quadrupole moments, and E 2 reduced transition matrix elements accurately reproduce available data and exhibit more-pronounced discontinuities at neutron number N =90 compared with the adjacent even-even Sm and Gd isotopes. The enhancement of the first-order quantum phase transition in odd-mass systems can be attributed to a shape polarization effect of the unpaired proton which, at the critical neutron number, starts predominantly coupling to Gd core nuclei that are characterized by larger quadrupole deformation and weaker proton pairing correlations compared with the corresponding Sm isotopes.

Geiger-Nuttall Law for Nuclei in Strong Electromagnetic Fields.

PubMed

Delion, D S; Ghinescu, S A

2017-11-17

We investigate the influence of a strong laser electromagnetic field on the α-decay rate by using the Hennenberger frame of reference. We introduce an adimensional parameter D=S_{0}/R_{0}, where R_{0} is the geometrical nuclear radius and S_{0}∼sqrt[I]/ω^{2} is a length parameter depending on the laser intensity I and frequency ω. We show that the barrier penetrability has a strong increase for intensities corresponding to D>D_{crit}=1, due to the fact that the resulting Coulomb potential becomes strongly anisotropic even for spherical nuclei. As a consequence, the contribution of the monopole term increases the barrier penetrability by 2 orders of magnitude, while the total contribution has an effect of 6 orders of magnitude at D∼3D_{crit}. In the case of deformed nuclei, the electromagnetic field increases the penetrability by an additional order of magnitude for a quadrupole deformation β_{2}∼0.3. The influence of the electromagnetic field can be expressed in terms of a shifted Geiger-Nuttal law by a term depending on S_{0} and deformation.

Geiger-Nuttall Law for Nuclei in Strong Electromagnetic Fields

NASA Astrophysics Data System (ADS)

Delion, D. S.; Ghinescu, S. A.

2017-11-01

We investigate the influence of a strong laser electromagnetic field on the α -decay rate by using the Hennenberger frame of reference. We introduce an adimensional parameter D =S0/R0, where R0 is the geometrical nuclear radius and S0˜√{I }/ω2 is a length parameter depending on the laser intensity I and frequency ω . We show that the barrier penetrability has a strong increase for intensities corresponding to D >Dcrit=1 , due to the fact that the resulting Coulomb potential becomes strongly anisotropic even for spherical nuclei. As a consequence, the contribution of the monopole term increases the barrier penetrability by 2 orders of magnitude, while the total contribution has an effect of 6 orders of magnitude at D ˜3 Dcrit. In the case of deformed nuclei, the electromagnetic field increases the penetrability by an additional order of magnitude for a quadrupole deformation β2˜0.3 . The influence of the electromagnetic field can be expressed in terms of a shifted Geiger-Nuttal law by a term depending on S0 and deformation.

Anisotropy and chemical composition of ultra-high energy cosmic rays using arrival directions measured by the Pierre Auger Observatory

NASA Astrophysics Data System (ADS)

Pierre Auger Collaboration; Abreu, P.; Aglietta, M.; Ahn, E. J.; Albuquerque, I. F. M.; Allard, D.; Allekotte, I.; Allen, J.; Allison, P.; Alvarez Castillo, J.; Alvarez-Muñiz, J.; Ambrosio, M.; Aminaei, A.; Anchordoqui, L.; Andringa, S.; Antičić, T.; Anzalone, A.; Aramo, C.; Arganda, E.; Arqueros, F.; Asorey, H.; Assis, P.; Aublin, J.; Ave, M.; Avenier, M.; Avila, G.; Bäcker, T.; Balzer, M.; Barber, K. B.; Barbosa, A. F.; Bardenet, R.; Barroso, S. L. C.; Baughman, B.; Bäuml, J.; Beatty, J. J.; Becker, B. R.; Becker, K. H.; Bellétoile, A.; Bellido, J. A.; BenZvi, S.; Berat, C.; Bertou, X.; Biermann, P. L.; Billoir, P.; Blanco, F.; Blanco, M.; Bleve, C.; Blümer, H.; Boháčová, M.; Boncioli, D.; Bonifazi, C.; Bonino, R.; Borodai, N.; Brack, J.; Brogueira, P.; Brown, W. C.; Bruijn, R.; Buchholz, P.; Bueno, A.; Burton, R. E.; Caballero-Mora, K. S.; Caramete, L.; Caruso, R.; Castellina, A.; Catalano, O.; Cataldi, G.; Cazon, L.; Cester, R.; Chauvin, J.; Cheng, S. H.; Chiavassa, A.; Chinellato, J. A.; Chou, A.; Chudoba, J.; Clay, R. W.; Coluccia, M. R.; Conceição, R.; Contreras, F.; Cook, H.; Cooper, M. J.; Coppens, J.; Cordier, A.; Cotti, U.; Coutu, S.; Covault, C. E.; Creusot, A.; Criss, A.; Cronin, J.; Curutiu, A.; Dagoret-Campagne, S.; Dallier, R.; Dasso, S.; Daumiller, K.; Dawson, B. R.; de Almeida, R. M.; De Domenico, M.; De Donato, C.; de Jong, S. J.; De La Vega, G.; de Mello Junior, W. J. M.; de Mello Neto, J. R. T.; De Mitri, I.; de Souza, V.; de Vries, K. D.; Decerprit, G.; del Peral, L.; Deligny, O.; Dembinski, H.; Dhital, N.; Di Giulio, C.; Diaz, J. C.; Díaz Castro, M. L.; Diep, P. N.; Dobrigkeit, C.; Docters, W.; D'Olivo, J. C.; Dong, P. N.; Dorofeev, A.; dos Anjos, J. C.; Dova, M. T.; D'Urso, D.; Dutan, I.; Ebr, J.; Engel, R.; Erdmann, M.; Escobar, C. O.; Etchegoyen, A.; Facal San Luis, P.; Fajardo Tapia, I.; Falcke, H.; Farrar, G.; Fauth, A. C.; Fazzini, N.; Ferguson, A. P.; Ferrero, A.; Fick, B.; Filevich, A.; Filipčič, A.; Fliescher, S.; Fracchiolla, C. E.; Fraenkel, E. D.; Fröhlich, U.; Fuchs, B.; Gaior, R.; Gamarra, R. F.; Gambetta, S.; García, B.; García Gámez, D.; Garcia-Pinto, D.; Gascon, A.; Gemmeke, H.; Gesterling, K.; Ghia, P. L.; Giaccari, U.; Giller, M.; Glass, H.; Gold, M. S.; Golup, G.; Gomez Albarracin, F.; Gómez Berisso, M.; Gonçalves, P.; Gonzalez, D.; Gonzalez, J. G.; Gookin, B.; Góra, D.; Gorgi, A.; Gouffon, P.; Gozzini, S. R.; Grashorn, E.; Grebe, S.; Griffith, N.; Grigat, M.; Grillo, A. F.; Guardincerri, Y.; Guarino, F.; Guedes, G. P.; Guzman, A.; Hague, J. D.; Hansen, P.; Harari, D.; Harmsma, S.; Harton, J. L.; Haungs, A.; Hebbeker, T.; Heck, D.; Herve, A. E.; Hojvat, C.; Hollon, N.; Holmes, V. C.; Homola, P.; Hörandel, J. R.; Horneffer, A.; Hrabovský, M.; Huege, T.; Insolia, A.; Ionita, F.; Italiano, A.; Jarne, C.; Jiraskova, S.; Kadija, K.; Kampert, K. H.; Karhan, P.; Kasper, P.; Kégl, B.; Keilhauer, B.; Keivani, A.; Kelley, J. L.; Kemp, E.; Kieckhafer, R. M.; Klages, H. O.; Kleifges, M.; Kleinfeller, J.; Knapp, J.; Koang, D.-H.; Kotera, K.; Krohm, N.; Krömer, O.; Kruppke-Hansen, D.; Kuehn, F.; Kuempel, D.; Kulbartz, J. K.; Kunka, N.; La Rosa, G.; Lachaud, C.; Lautridou, P.; Leão, M. S. A. B.; Lebrun, D.; Lebrun, P.; Leigui de Oliveira, M. A.; Lemiere, A.; Letessier-Selvon, A.; Lhenry-Yvon, I.; Link, K.; López, R.; Lopez Aüera, A.; Louedec, K.; Lozano Bahilo, J.; Lucero, A.; Ludwig, M.; Lyberis, H.; Maccarone, M. C.; Macolino, C.; Maldera, S.; Mandat, D.; Mantsch, P.; Mariazzi, A. G.; Marin, J.; Marin, V.; Maris, I. C.; Marquez Falcon, H. R.; Marsella, G.; Martello, D.; Martin, L.; Martinez, H.; Martínez Bravo, O.; Mathes, H. J.; Matthews, J.; Matthews, J. A. J.; Matthiae, G.; Maurizio, D.; Mazur, P. O.; Medina-Tanco, G.; Melissas, M.; Melo, D.; Menichetti, E.; Menshikov, A.; Mertsch, P.; Meurer, C.; Mićanović, S.; Micheletti, M. I.; Miller, W.; Miramonti, L.; Mollerach, S.; Monasor, M.; Monnier Ragaigne, D.; Montanet, F.; Morales, B.; Morello, C.; Moreno, E.; Moreno, J. C.; Morris, C.; Mostafá, M.; Moura, C. A.; Mueller, S.; Muller, M. A.; Müller, G.; Münchmeyer, M.; Mussa, R.; Navarra, G.; Navarro, J. L.; Navas, S.; Necesal, P.; Nellen, L.; Nelles, A.; Nhung, P. T.; Niemietz, L.; Nierstenhoefer, N.; Nitz, D.; Nosek, D.; Nožka, L.; Nyklicek, M.; Oehlschläger, J.; Olinto, A.; Oliva, P.; Olmos-Gilbaja, V. M.; Ortiz, M.; Pacheco, N.; Pakk Selmi-Dei, D.; Palatka, M.; Pallotta, J.; Palmieri, N.; Parente, G.; Parizot, E.; Parra, A.; Parsons, R. D.; Pastor, S.; Paul, T.; Pech, M.; Pȩkala, J.; Pelayo, R.; Pepe, I. M.; Perrone, L.; Pesce, R.; Petermann, E.; Petrera, S.; Petrinca, P.; Petrolini, A.; Petrov, Y.; Petrovic, J.; Pfendner, C.; Phan, N.; Piegaia, R.; Pierog, T.; Pieroni, P.; Pimenta, M.; Pirronello, V.; Platino, M.; Ponce, V. H.; Pontz, M.; Privitera, P.; Prouza, M.; Quel, E. J.; Querchfeld, S.; Rautenberg, J.; Ravel, O.; Ravignani, D.; Revenu, B.; Ridky, J.; Riggi, S.; Risse, M.; Ristori, P.; Rivera, H.; Rizi, V.; Roberts, J.; Robledo, C.; Rodrigues de Carvalho, W.; Rodriguez, G.; Rodriguez Martino, J.; Rodriguez Rojo, J.; Rodriguez-Cabo, I.; Rodríguez-Frías, M. D.; Ros, G.; Rosado, J.; Rossler, T.; Roth, M.; Rouillé-d'Orfeuil, B.; Roulet, E.; Rovero, A. C.; Rühle, C.; Salamida, F.; Salazar, H.; Salina, G.; Sánchez, F.; Santander, M.; Santo, C. E.; Santos, E.; Santos, E. M.; Sarazin, F.; Sarkar, B.; Sarkar, S.; Sato, R.; Scharf, N.; Scherini, V.; Schieler, H.; Schiffer, P.; Schmidt, A.; Schmidt, F.; Schmidt, T.; Scholten, O.; Schoorlemmer, H.; Schovancova, J.; Schovánek, P.; Schöder, F.; Schulte, S.; Schuster, D.; Sciutto, S. J.; Scuderi, M.; Segreto, A.; Settimo, M.; Shadkam, A.; Shellard, R. C.; Sidelnik, I.; Sigl, G.; Silva Lopez, H. H.; Śmiałkowski, A.; Šmída, R.; Snow, G. R.; Sommers, P.; Sorokin, J.; Spinka, H.; Squartini, R.; Stapleton, J.; Stasielak, J.; Stephan, M.; Strazzeri, E.; Stutz, A.; Suarez, F.; Suomijärvi, T.; Supanitsky, A. D.; Šuša, T.; Sutherland, M. S.; Swain, J.; Szadkowski, Z.; Szuba, M.; Tamashiro, A.; Tapia, A.; Tartare, M.; Taşcąu, O.; Tavera Ruiz, C. G.; Tcaciuc, R.; Tegolo, D.; Thao, N. T.; Thomas, D.; Tiffenberg, J.; Timmermans, C.; Tiwari, D. K.; Tkaczyk, W.; Todero Peixoto, C. J.; Tomé, B.; Tonachini, A.; Travnicek, P.; Tridapalli, D. B.; Tristram, G.; Trovato, E.; Tueros, M.; Ulrich, R.; Unger, M.; Urban, M.; Valdés Galicia, J. F.; Valiño, I.; Valore, L.; van den Berg, A. M.; Varela, E.; Vargas Cáardenas, B.; Vázquez, J. R.; Vázquez, R. A.; Veberič, D.; Verzi, V.; Vicha, J.; Videla, M.; Villaseñor, L.; Wahlberg, H.; Wahrlich, P.; Wainberg, O.; Warner, D.; Watson, A. A.; Weber, M.; Weidenhaupt, K.; Weindl, A.; Westerhoff, S.; Whelan, B. J.; Wieczorek, G.; Wiencke, L.; Wilczyńska, B.; Wilczyński, H.; Will, M.; Williams, C.; Winchen, T.; Winders, L.; Winnick, M. G.; Wommer, M.; Wundheiler, B.; Yamamoto, T.; Yapici, T.; Younk, P.; Yuan, G.; Yushkov, A.; Zamorano, B.; Zas, E.; Zavrtanik, D.; Zavrtanik, M.; Zaw, I.; Zepeda, A.; Ziolkowski, M.

2011-06-01

The Pierre Auger Collaboration has reported evidence for anisotropy in the distribution of arrival directions of the cosmic rays with energies E > Eth = 5.5 × 1019 eV. These show a correlation with the distribution of nearby extragalactic objects, including an apparent excess around the direction of Centaurus A. If the particles responsible for these excesses at E > Eth are heavy nuclei with charge Z, the proton component of the sources should lead to excesses in the same regions at energies E/Z. We here report the lack of anisotropies in these directions at energies above Eth/Z (for illustrative values of Z = 6,13,26). If the anisotropies above Eth are due to nuclei with charge Z, and under reasonable assumptions about the acceleration process, these observations imply stringent constraints on the allowed proton fraction at the lower energies.

On the equivalence of experimental B(E2) values determined by various techniques

DOE PAGES

Birch, M.; Pritychenko, B.; Singh, B.

2016-06-30

In this paper, we establish the equivalence of the various techniques for measuring B(E2) values using a statistical analysis. Data used in this work come from the recent compilation by B. Pritychenko et al. (2016). We consider only those nuclei for which the B(E2) values were measured by at least two different methods, with each method being independently performed at least twice. Our results indicate that most prevalent methods of measuring B(E2) values are equivalent, with some weak evidence that Doppler-shift attenuation method (DSAM) measurements may differ from Coulomb excitation (CE) and nuclear resonance fluorescence (NRF) measurements. However, such anmore » evidence appears to arise from discrepant DSAM measurements of the lifetimes for 60Ni and some Sn nuclei rather than a systematic deviation in the method itself.« less

Electron-positron pair production in ion collisions at low velocity beyond Born approximation

NASA Astrophysics Data System (ADS)

Lee, R. N.; Milstein, A. I.

2016-10-01

We derive the spectrum and the total cross section of electromagnetic e+e- pair production in the collisions of two nuclei at low relative velocity β. Both free-free and bound-free e+e- pair production is considered. The parameters ηA,B =ZA,B α are assumed to be small compared to unity but arbitrary compared to β (ZA,B are the charge numbers of the nuclei and α is the fine structure constant). Due to a suppression of the Born term by high power of β, the first Coulomb correction to the amplitude appears to be important at ηA,B ≳ β. The effect of a finite nuclear mass is discussed. In contrast to the result obtained in the infinite nuclear mass limit, the terms ∝M-2 are not suppressed by the high power of β and may easily dominate at sufficiently small velocities.

Field evidence for linking Altosid applications with increased amphibian deformities in southern leopard frogs [abstract

USGS Publications Warehouse

Sparling, D.W.

1998-01-01

During the summer of 1997 we repeatedly sprayed Altosid, a formulation of 4% methoprene used for mosquito control, on six constructed macrocosms. Six additional macrocosms were sprayed with Abate4E, containing the organophosphate pesticide temephos, and six were sprayed with water (controls). The wetlands were created on an impermeable foundation for research purposes and averaged 215 m2 in area and 0.5 m deep. Application rates and frequency of Abate4E and Altosid followed label directions and mimicked procedures for mosquito control in National Wildlife Refuges. In early September juvenile frogs and metamorphing tadpoles were collected with dip nets from each pond and examined for deformities. In all, 91 juveniles and metamorph southern leopard frogs (Rana utricularia) were collected from Altosid sprayed wetlands with 14 (15%) demonstrating deformities. Seventyseven juveniles and metamorphs were collected from control wetlands with three (4%) showing deformities. Only six juveniles and metamorphs were collected from Abate4E wetlands and none showed deformities. Deformities included missing or deformed hind limbs (9 of 10 involving only the right hind limb), missing eyes, and abnormal color. The differences in rate of deformities was dependent on treatment (X2=6.44, p< 0.02). The number of leopard frogs caught per unit effort (tadpoles and juveniles) differed among treatments (p=0.032) with Abate4E wetlands producing fewer individuals per capture effort than either Altosid or control wetlands.

A drop in uniaxial and biaxial nonlinear extensional flows

NASA Astrophysics Data System (ADS)

Favelukis, M.

2017-08-01

In this theoretical report, we explore small deformations of an initially spherical drop subjected to uniaxial or biaxial nonlinear extensional creeping flows. The problem is governed by the capillary number (Ca), the viscosity ratio (λ), and the nonlinear intensity of the flow (E). When the extensional flow is linear (E = 0), the familiar internal circulations are obtained and the same is true with E > 0, except that the external and internal flow rates increase with increasing E. If E < 0, the external flow consists of some unconnected regions leading to the same number of internal circulations (-3/7 < E < 0) or twice the number of internal circulations (E < -3/7), when compared to the linear case. The shape of the deformed drop is represented in terms of a modified Taylor deformation parameter, and the conditions for the breakup of the drop by a center pinching mechanism are also established. When the flow is linear (E = 0), the literature predicts prolate spheroidal drops for uniaxial flows (Ca > 0) and oblate spheroidal drops for biaxial flows (Ca < 0). For the same |Ca|, if E > 0, the drop is more elongated than the linear case, while E < 0 results in less elongated drops than the linear case. Compared to the linear case, for both uniaxial and biaxial extensional flows, E > 0 tends to facilitate drop breakup, while E < 0 makes drop breakup more difficult.

Evolution of Structure in Nuclei: Meditation by Sub-Shell Modifications and Relation to Binding Energies

NASA Astrophysics Data System (ADS)

Casten, R. F.; Cakirli, R. B.

2009-03-01

Understanding the development of configuration mixing, coherence, collectivity, and deformation in nuclei is one of the crucial challenges in nuclear structure physics, and one which has become all the more important with the advent of next generation facilities for the study of exotic nuclei. We will discuss recent work on phase/shape transitional behavior in nuclei, and the role of changes in sub-shell structure in mediating such transitional regions. We will also discuss a newly found, much deeper, link between nuclear structure and nuclear binding energies.

Multi-tissue and multi-scale approach for nuclei segmentation in H&E stained images.

PubMed

Salvi, Massimo; Molinari, Filippo

2018-06-20

Accurate nuclei detection and segmentation in histological images is essential for many clinical purposes. While manual annotations are time-consuming and operator-dependent, full automated segmentation remains a challenging task due to the high variability of cells intensity, size and morphology. Most of the proposed algorithms for the automated segmentation of nuclei were designed for specific organ or tissues. The aim of this study was to develop and validate a fully multiscale method, named MANA (Multiscale Adaptive Nuclei Analysis), for nuclei segmentation in different tissues and magnifications. MANA was tested on a dataset of H&E stained tissue images with more than 59,000 annotated nuclei, taken from six organs (colon, liver, bone, prostate, adrenal gland and thyroid) and three magnifications (10×, 20×, 40×). Automatic results were compared with manual segmentations and three open-source software designed for nuclei detection. For each organ, MANA obtained always an F1-score higher than 0.91, with an average F1 of 0.9305 ± 0.0161. The average computational time was about 20 s independently of the number of nuclei to be detected (anyway, higher than 1000), indicating the efficiency of the proposed technique. To the best of our knowledge, MANA is the first fully automated multi-scale and multi-tissue algorithm for nuclei detection. Overall, the robustness and versatility of MANA allowed to achieve, on different organs and magnifications, performances in line or better than those of state-of-art algorithms optimized for single tissues.

Deformation of nuclei as a function of angular momentum in the U(6) ⊃ SU(3) model

NASA Astrophysics Data System (ADS)

Partensky, A.; Quesne, C.

1982-08-01

Moshińsky proposed recently a hybrid rotational model resulting from a comparison between the Gneuss and Greiner extension of the Bohr-Mottelson model and the interacting boson model. In this hybrid rotational model, we study the shape of nuclei by calculating the average of the expectation value of the square of the deformation parameter β with respect to the rotational states with the same angular momentum belonging to a given irreducible representation of SU(3). This work generalizes to three dimensions the corresponding analysis carried out in two dimensions by Chacón, Moshińsky, and Vanagas. We use the canonical chain of U(3) to obtain an analytical formula for the quantity studied. The overall stretching effect of the angular momentum on the shape of nuclei is demonstrated.

Lifetimes of excited states in triaxially deformed 107Tc and 109,111,113Rh

NASA Astrophysics Data System (ADS)

Hagen, T. W.; Görgen, A.; Korten, W.; Grente, L.; Salsac, M.-D.; Farget, F.; Braunroth, T.; Bruyneel, B.; Celikovic, I.; Clément, E.; de France, G.; Delaune, O.; Dewald, A.; Dijon, A.; Hackstein, M.; Jacquot, B.; Litzinger, J.; Ljungvall, J.; Louchart, C.; Michelagnoli, C.; Napoli, D. R.; Recchia, F.; Rother, W.; Sahin, E.; Siem, S.; Sulignano, B.; Theisen, Ch.; Valiente-Dobon, J. J.

2018-03-01

Lifetimes of excited states in 107Tc, 109Rh, 111Rh, and 113Rh were measured at GANIL using the Recoil-Distance Doppler Shift method. The neutron-rich nuclei were produced in fission reactions in inverse kinematics with a 238U beam impinging on a 9Be target. Fission fragments were identified event-by-event in the ray-tracing spectrometer VAMOS++ and correlated with prompt γ rays observed around the target position with the EXOGAM Ge detector array. Several lifetimes were obtained for states in the positive-parity yrast bands in the four nuclei and compared to triaxial particle-rotor calculations. The results clarify the configuration for the strongest positive-parity band in 107Tc and suggest a gradual increase of triaxial deformation with atomic number Z, reaching almost maximum triaxiality for the neutron-rich Rh nuclei.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Butler, P. A., E-mail: peter.butler@liverpool.ac.uk

2016-07-07

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

Expression of S100 beta in sensory and secretory cells of the vertebrate inner ear

NASA Technical Reports Server (NTRS)

Fermin, C. D.; Martin, D. S.

1995-01-01

We evaluated anti-S100 beta expression in the chick (Gallus domesticus) inner ear and determined that: 1) the monomer anti-S100 beta is expressed differentially in the vestibular and auditory perikarya; 2) expression of S100 beta in the afferent nerve terminals is time-related to synapse and myelin formation; 3) the expression of the dimer anti-S100 alpha alpha beta beta and monomer anti-S100 beta overlaps in most inner ear cell types. Most S100 alpha alpha beta beta positive cells express S100 beta, but S100 beta positive cells do not always express S100 alpha alpha beta beta. 4) the expression of S100 beta is diffused over the perikaryal cytoplasm and nuclei of the acoustic ganglia but is concentrated over the nuclei of the vestibular perikarya. 6) S100 beta is expressed in secretory cells, and it is co-localized with GABA in sensory cells. 7) Color thresholding objective quantitation indicates that the amount of S100 beta was higher (mean 22, SD +/- 4) at E19 than at E9 (mean 34, SD +/- 3) in afferent axons. 8) Moreover, S100 beta was unchanged between E11-E19 in the perikaryal cytoplasm, but did change over the nuclei. At E9, 74%, and at E21, 5% of vestibular perikarya were positive. The data suggest that S100 beta may be physically associated with neuronal and ionic controlling cells of the vertebrate inner ear, where it could provide a dual ionic and neurotrophic modulatory function.

Shape coexistence and shape transition in light nuclei

NASA Astrophysics Data System (ADS)

Saxena, G.; Kumawat, M.; Singh, U. K.; Kaushik, M.; Jain, S. K.

2018-05-01

A systematic study has been performed to investigate the shape coexistence and shape transition for even-even nuclei between Z = 10-20 by employing Relativistic Mean-Filed plus BCS (RMF+BCS) approach. We calculate ground state properties viz. binding energy, deformation etc. for even-even nuclei to find the shape coexistence and shape transition. These results are found in agreement of recent experiments and consistent with other parameters of RMF and other theories.

Physical Characteristics of Asteroid-like Comet Nucleus C/2001 OG108 (LONEOS)

NASA Technical Reports Server (NTRS)

Abell, P. A.; Fernandez, Y. R.; Pravec, P.; French, L. M.; Farnham, T. L.; Gaffey, M. J.; Hardersen, P. S.; Kusnirak, P.; Sarounova, L.; Sheppard, S. S.

2003-01-01

For many years several investigators have suggested that some portion of the near-Earth asteroid population may actually be extinct cometary nuclei. Evidence used to support these hypotheses was based on: observations of asteroid orbits and associated meteor showers (e.g. 3200 Phaethon and the Geminid meteor shower); low activity of short period comet nuclei, which implied nonvolatile surface crusts (e.g. Neujmin 1, Arend-Rigaux); and detections of transient cometary activity in some near-Earth asteroids (e.g. 4015 Wilson-Harrington). Recent investigations have suggested that approximately 5-10% of the near- Earth asteroid population may be extinct comets. However if members of the near-Earth asteroid population are extinct cometary nuclei, then there should be some objects within this population that are near their final stages of evolution and so should demonstrate only low levels of activity. The recent detections of coma from near-Earth object 2001 OG108 have renewed interest in this possible comet-asteroid connection. This paper presents the first high quality ground-based near-infrared reflectance spectrum of a comet nucleus combined with detailed lightcurve and albedo measurements.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kumar, S.; Sihotra, S.; Singh, K.

The level structures in {sup 98,99}Rh, and {sup 99}Pd nuclei have been investigated through in beam γ-ray spectroscopic techniques following the {sup 75}As({sup 28}Si, xpyn) fusion-evaporation reaction at E{sub lab} = 120 MeV. These investigations were carried out using Indian-National-Gamma-Array (INGA) consisting of Compton-suppressed clover detectors at the Inter-University Accelerator Centre, New Delhi. The level structures observed in {sup 99}Pd, and {sup 98,99}Rh have been established up to ∼ 11 MeV, 10 MeV and 16 MeV excitation energy and spin ∼ 23ħ, 23ħ, and 28ħ respectively. In the doubly-odd {sup 98}Rh nucleus, new band structures and isomeric states have beenmore » identified at lower spins and new states below the previously identified 2{sup +} ground state (T{sub 1/2} = 8.5 m) are identified. In the present work {sup 99}Rh structure have been observed similar to {sup 101}Rh which is based on p{sub 1/2} and g{sub 9/2} orbitals. Various positive and negative parity states in these nuclei are observed to be energetically more favored with respect to the neighboring ones, and are likely to be the maximally aligned states obtained by angular momentum coupling of the valence particles (holes). The level structures observed in {sup 99}Pd have been interpreted in the framework of a microscopic theory based on the deformed Hartree-Fock (HF) and angular momentum projection techniques. Band structures at low excitation energy are based on the low-Ω νg{sub 7/2} and νd{sub 5/2} orbitals, have been observed in {sup 99}Pd. Band structure at higher spins are reproduced with the ν(g{sub 7/2}){sup 2}⊗ν(g{sub 9/2}){sup −1}⊗ν(h{sub 11/2}){sup 2}⊗π(g{sub 9/2}){sup 6} configurations. Observation of new E1 transitions linking the opposite parity νh{sub 11/2} and νd{sub 5/2} bands provide fingerprints of possible octupole correlations in {sup 99}Pd. The extracted values of the B(E1)/B(E2) ratios for the lower levels in the νh{sub 11/2} band are ∼ 10{sup −7} [fm]{sup −2}.« less

Shear fabrics reveal orogen-parallel deformations, NW Lesser Garhwal Himalaya, Uttarakhand, India

NASA Astrophysics Data System (ADS)

Biswas, T.; Bose, N.; Mukherjee, S.

2017-12-01

Shear deformation along the Himalayan belt is poorly understood unlike that across the orogen. Field observations and structural analysis along Bhagirathi river section along the National Highway 34 reveals NW Lesser Himalaya (Garhwal region, India) suffered both compression and extension parallel to the orogenic belt and thus forms a unique venue of great structural and tectonic interest. Meso-scale ductile- and brittle shear fabrics, such as S-C, C-P, Y-P, Y-S; are emphasized describing such deformations. Extensional shear fabric strikes N43oE and compressional shear fabrics N39.5oE, which are at a low-angle with the orogenic trend. Our study reviews orogen parallel deformation, both extension as well as compression, taking examples from other part of the world (e.g., Central Andes, N Apennines and SW Alps) and from other terrains in the Himalaya. Proposed models are evaluated and compared with the study area. The results shows that the pre-existing remnant structures (e.g., the Delhi-Haridwar ridge) on the under-thrusting Indian shield/plate plays a vital role in modifying thin-skinned tectonics along with migration of the eastward extrusion of the Tibetian plateau (hinterland deformation) into the Himalayan foreland.

Red blood cell dynamics: from cell deformation to ATP release.

PubMed

Wan, Jiandi; Forsyth, Alison M; Stone, Howard A

2011-10-01

The mechanisms of red blood cell (RBC) deformation under both static and dynamic, i.e., flow, conditions have been studied extensively since the mid 1960s. Deformation-induced biochemical reactions and possible signaling in RBCs, however, were proposed only fifteen years ago. Therefore, the fundamental relationship between RBC deformation and cellular signaling dynamics i.e., mechanotransduction, remains incompletely understood. Quantitative understanding of the mechanotransductive pathways in RBCs requires integrative studies of physical models of RBC deformation and cellular biochemical reactions. In this article we review the physical models of RBC deformation, spanning from continuum membrane mechanics to cellular skeleton dynamics under both static and flow conditions, and elaborate the mechanistic links involved in deformation-induced ATP release. This journal is © The Royal Society of Chemistry 2011

Arbitrary amplitude nucleus-acoustic solitons in multi-ion quantum plasmas with relativistically degenerate electrons

NASA Astrophysics Data System (ADS)

Sultana, S.; Schlickeiser, R.

2018-02-01

A three component degenerate relativistic quantum plasma (consisting of relativistically degenerate electrons, nondegenerate inertial light nuclei, and stationary heavy nuclei) is considered to model the linear wave and also the electrostatic solitary waves in the light nuclei-scale length. A well-known normal mode analysis is employed to investigate the linear wave properties. A mechanical-motion analog (Sagdeev-type) pseudo-potential approach, which reveals the existence of large amplitude solitary excitations, is adopted to study the nonlinear wave properties. Only the positive potential solitary excitations are found to exist in the plasma medium under consideration. The basic properties of the arbitrary amplitude electrostatic acoustic modes in the light nuclei-scale length and their existence domain in terms of soliton speed (Mach number) are examined. The modifications of solitary wave characteristics and their existence domain with the variation of different key plasma configuration parameters (e.g., electrons degeneracy parameter, inertial light nuclei number density, and degenerate electron number density) are also analyzed. Our results, which may be helpful to explain the basic features of the nonlinear wave propagation in multi-component degenerate quantum plasmas, in connection with astrophysical compact objects (e.g., white dwarfs) are briefly discussed.

Towards automated segmentation of cells and cell nuclei in nonlinear optical microscopy.

PubMed

Medyukhina, Anna; Meyer, Tobias; Schmitt, Michael; Romeike, Bernd F M; Dietzek, Benjamin; Popp, Jürgen

2012-11-01

Nonlinear optical (NLO) imaging techniques based e.g. on coherent anti-Stokes Raman scattering (CARS) or two photon excited fluorescence (TPEF) show great potential for biomedical imaging. In order to facilitate the diagnostic process based on NLO imaging, there is need for an automated calculation of quantitative values such as cell density, nucleus-to-cytoplasm ratio, average nuclear size. Extraction of these parameters is helpful for the histological assessment in general and specifically e.g. for the determination of tumor grades. This requires an accurate image segmentation and detection of locations and boundaries of cells and nuclei. Here we present an image processing approach for the detection of nuclei and cells in co-registered TPEF and CARS images. The algorithm developed utilizes the gray-scale information for the detection of the nuclei locations and the gradient information for the delineation of the nuclear and cellular boundaries. The approach reported is capable for an automated segmentation of cells and nuclei in multimodal TPEF-CARS images of human brain tumor samples. The results are important for the development of NLO microscopy into a clinically relevant diagnostic tool. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Search for Medium Modifications of the ρ Meson

NASA Astrophysics Data System (ADS)

Nasseripour, R.; Wood, M. H.; Djalali, C.; Weygand, D. P.; Tur, C.; Mosel, U.; Muehlich, P.; Adams, G.; Amaryan, M. J.; Ambrozewicz, P.; Anghinolfi, M.; Asryan, G.; Avakian, H.; Bagdasaryan, H.; Baillie, N.; Ball, J. P.; Baltzell, N. A.; Barrow, S.; Battaglieri, M.; Bedlinskiy, I.; Bektasoglu, M.; Bellis, M.; Benmouna, N.; Berman, B. L.; Biselli, A. S.; Blaszczyk, L.; Bouchigny, S.; Boiarinov, S.; Bradford, R.; Branford, D.; Briscoe, W. J.; Brooks, W. K.; Bültmann, S.; Burkert, V. D.; Butuceanu, C.; Calarco, J. R.; Careccia, S. L.; Carman, D. S.; Carnahan, B.; Casey, L.; Chen, S.; Cole, P. L.; Collins, P.; Coltharp, P.; Crabb, D.; Crannell, H.; Crede, V.; Cummings, J. P.; Dashyan, N.; de Masi, R.; de Vita, R.; de Sanctis, E.; Degtyarenko, P. V.; Denizli, H.; Dennis, L.; Deur, A.; Dharmawardane, K. V.; Dickson, R.; Dodge, G. E.; Doughty, D.; Dugger, M.; Dytman, S.; Dzyubak, O. P.; Egiyan, H.; Egiyan, K. S.; El Fassi, L.; Elouadrhiri, L.; Eugenio, P.; Fedotov, G.; Feldman, G.; Feuerbach, R. J.; Funsten, H.; Garçon, M.; Gavalian, G.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Gordon, C. I. O.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guler, N.; Guo, L.; Gyurjyan, V.; Hadjidakis, C.; Hafidi, K.; Hakobyan, H.; Hakobyan, R. S.; Hanretty, C.; Hardie, J.; Hersman, F. W.; Hicks, K.; Hleiqawi, I.; Holtrop, M.; Hyde-Wright, C. E.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Ito, M. M.; Jenkins, D.; Jo, H. S.; Johnstone, J. R.; Joo, K.; Juengst, H. G.; Kalantarians, N.; Kellie, J. D.; Khandaker, M.; Kim, W.; Klein, A.; Klein, F. J.; Klimenko, A. V.; Kossov, M.; Krahn, Z.; Kramer, L. H.; Kubarovsky, V.; Kuhn, J.; Kuhn, S. E.; Kuleshov, S. V.; Lachniet, J.; Laget, J. M.; Langheinrich, J.; Lawrence, D.; Li, Ji; Livingston, K.; Lu, H. Y.; MacCormick, M.; Markov, N.; Mattione, P.; McAleer, S.; McKinnon, B.; McNabb, J. W. C.; Mecking, B. A.; Mehrabyan, S.; Melone, J. J.; Mestayer, M. D.; Meyer, C. A.; Mibe, T.; Mikhailov, K.; Minehart, R.; Mirazita, M.; Miskimen, R.; Mokeev, V.; Moriya, K.; Morrow, S. A.; Moteabbed, M.; Mueller, J.; Munevar, E.; Mutchler, G. S.; Nadel-Turonski, P.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Niczyporuk, B. B.; Niroula, M. R.; Niyazov, R. A.; Nozar, M.; Osipenko, M.; Ostrovidov, A. I.; Park, K.; Pasyuk, E.; Paterson, C.; Pereira, S. Anefalos; Pierce, J.; Pivnyuk, N.; Pocanic, D.; Pogorelko, O.; Pozdniakov, S.; Preedom, B. M.; Price, J. W.; Prok, Y.; Protopopescu, D.; Raue, B. A.; Riccardi, G.; Ricco, G.; Ripani, M.; Ritchie, B. G.; Ronchetti, F.; Rosner, G.; Rossi, P.; Sabatié, F.; Salamanca, J.; Salgado, C.; Santoro, J. P.; Sapunenko, V.; Schumacher, R. A.; Serov, V. S.; Sharabian, Y. G.; Sharov, D.; Shvedunov, N. V.; Smith, E. S.; Smith, L. C.; Sober, D. I.; Sokhan, D.; Stavinsky, A.; Stepanyan, S. S.; Stepanyan, S.; Stokes, B. E.; Stoler, P.; Strakovsky, I. I.; Strauch, S.; Taiuti, M.; Tedeschi, D. J.; Tkabladze, A.; Tkachenko, S.; Todor, L.; Ungaro, M.; Vineyard, M. F.; Vlassov, A. V.; Watts, D. P.; Weinstein, L. B.; Williams, M.; Wolin, E.; Yegneswaran, A.; Zana, L.; Zhang, B.; Zhang, J.; Zhao, B.; Zhao, Z. W.

2007-12-01

The photoproduction of vector mesons on various nuclei has been studied using the CLAS detector at Jefferson Laboratory. The vector mesons, ρ, ω, and ϕ, are observed via their decay to e+e-, in order to reduce the effects of final-state interactions in the nucleus. Of particular interest are possible in-medium effects on the properties of the ρ meson. The ρ mass spectrum is extracted from the data on various nuclei, H2, C, Fe, and Ti. We observe no significant mass shift and some broadening consistent with expected collisional broadening for the ρ meson.

Parallel Implementation of Numerical Solution of Few-Body Problem Using Feynman's Continual Integrals

NASA Astrophysics Data System (ADS)

Naumenko, Mikhail; Samarin, Viacheslav

2018-02-01

Modern parallel computing algorithm has been applied to the solution of the few-body problem. The approach is based on Feynman's continual integrals method implemented in C++ programming language using NVIDIA CUDA technology. A wide range of 3-body and 4-body bound systems has been considered including nuclei described as consisting of protons and neutrons (e.g., 3,4He) and nuclei described as consisting of clusters and nucleons (e.g., 6He). The correctness of the results was checked by the comparison with the exactly solvable 4-body oscillatory system and experimental data.

The reduced transition probabilities for excited states of rare-earths and actinide even-even nuclei

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ghumman, S. S.

The theoretical B(E2) ratios have been calculated on DF, DR and Krutov models. A simple method based on the work of Arima and Iachello is used to calculate the reduced transition probabilities within SU(3) limit of IBA-I framework. The reduced E2 transition probabilities from second excited states of rare-earths and actinide even–even nuclei calculated from experimental energies and intensities from recent data, have been found to compare better with those calculated on the Krutov model and the SU(3) limit of IBA than the DR and DF models.

Chiral electroweak currents in nuclei

DOE PAGES

Riska, D. O.; Schiavilla, R.

2017-01-10

Here, the development of the chiral dynamics based description of nuclear electroweak currents is reviewed. Gerald E. (Gerry) Brown’s role in basing theoretical nuclear physics on chiral Lagrangians is emphasized. Illustrative examples of the successful description of electroweak observables of light nuclei obtained from chiral effective field theory are presented.

In-beam studies of sup 96 Zr and sup 98 Zr: Collective excitations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Henry, E.A.; Meyer, R.A.; Aprahamian, A.

1988-04-18

Nearly two decades ago signatures of deformation in the ground state bands of {sup 100}Zr and {sup 102}Zr were identified, and the rapid change in the deformation of heavy zirconium nuclei noted. It is now well accepted that the short-range proton-neutron interaction between the 1g{sub 9/2} and 1g{sub 7/2} spin-orbit partners plays an important role in producing ground state deformation in this region. Nevertheless, recent studies of zirconium nuclei, including those in the transition region, continue to refine our understanding of the interplay between single-particle and collective degrees of freedom. In this report we discuss some aspects of the levelmore » structures of {sup 96}Zr and {sup 98}Zr with emphasis on collective excitations. 18 refs., 2 tabs.« less

In-medium similarity renormalization group for closed and open-shell nuclei

NASA Astrophysics Data System (ADS)

Hergert, H.

2017-02-01

We present a pedagogical introduction to the in-medium similarity renormalization group (IMSRG) framework for ab initio calculations of nuclei. The IMSRG performs continuous unitary transformations of the nuclear many-body Hamiltonian in second-quantized form, which can be implemented with polynomial computational effort. Through suitably chosen generators, it is possible to extract eigenvalues of the Hamiltonian in a given nucleus, or drive the Hamiltonian matrix in configuration space to specific structures, e.g., band- or block-diagonal form. Exploiting this flexibility, we describe two complementary approaches for the description of closed- and open-shell nuclei: the first is the multireference IMSRG (MR-IMSRG), which is designed for the efficient calculation of nuclear ground-state properties. The second is the derivation of non-empirical valence-space interactions that can be used as input for nuclear shell model (i.e., configuration interaction (CI)) calculations. This IMSRG+shell model approach provides immediate access to excitation spectra, transitions, etc, but is limited in applicability by the factorial cost of the CI calculations. We review applications of the MR-IMSRG and IMSRG+shell model approaches to the calculation of ground-state properties for the oxygen, calcium, and nickel isotopic chains or the spectroscopy of nuclei in the lower sd shell, respectively, and present selected new results, e.g., for the ground- and excited state properties of neon isotopes.

Valence p-n interactions and sufficient conditions for the development of collectivity in heavy nuclei

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sharon, Y.Y.

1988-04-01

The P scheme of Casten, Brenner, and Haustein is used to suggest that nuclei will always become deformed when there are more than 10 valence nucleons of each type (protons and neutrons). Utilizing this scheme, necessary and sufficient conditions are also suggested for the onset of nuclear collectivity.

Structural and decay properties of Z = 132, 138 superheavy nuclei

NASA Astrophysics Data System (ADS)

Rather, Asloob A.; Ikram, M.; Usmani, A. A.; Kumar, Bharat; Patra, S. K.

2016-12-01

In this paper, we analyze the structural properties of Z = 132 and Z = 138 superheavy nuclei within the ambit of axially deformed relativistic mean-field framework with NL3 * parametrization and calculate the total binding energies, radii, quadrupole deformation parameter, separation energies, density distributions. We also investigate the phenomenon of shape coexistence by performing the calculations for prolate, oblate and spherical configurations. For clear presentation of nucleon distributions, the two-dimensional contour representation of individual nucleon density and total matter density has been made. Further, a competition between possible decay modes such as α-decay, β-decay and spontaneous fission of the isotopic chain of superheavy nuclei with Z = 132 within the range 312 ≤ A ≤ 392 and 318 ≤ A ≤ 398 for Z = 138 is systematically analyzed within self-consistent relativistic mean-field model. From our analysis, we inferred that the α-decay and spontaneous fission are the principal modes of decay in majority of the isotopes of superheavy nuclei under investigation apart from β-decay as dominant mode of decay in 318-322138 isotopes.

Origin of fine structure of the giant dipole resonance in s d -shell nuclei

NASA Astrophysics Data System (ADS)

Fearick, R. W.; Erler, B.; Matsubara, H.; von Neumann-Cosel, P.; Richter, A.; Roth, R.; Tamii, A.

2018-04-01

A set of high-resolution zero-degree inelastic proton scattering data on 24Mg, 28Si, 32S, and 40Ca provides new insight into the long-standing puzzle of the origin of fragmentation of the giant dipole resonance (GDR) in s d -shell nuclei. Understanding is achieved by comparison with random phase approximation calculations for deformed nuclei using for the first time a realistic nucleon-nucleon interaction derived from the Argonne V18 potential with the unitary correlation operator method and supplemented by a phenomenological three-nucleon contact interaction. A wavelet analysis allows one to extract significant scales both in the data and calculations characterizing the fine structure of the GDR. The fair agreement for scales in the range of a few hundred keV supports the surmise that the fine structure arises from ground-state deformation driven by α clustering.

Deformed shell model calculations of half lives for β+/EC decay and 2ν β+β+/β+EC/ECEC decay in medium-heavy N~Z nuclei

NASA Astrophysics Data System (ADS)

Mishra, S.; Shukla, A.; Sahu, R.; Kota, V. K. B.

2008-08-01

The β+/EC half-lives of medium heavy N~Z nuclei with mass number A~64-80 are calculated within the deformed shell model (DSM) based on Hartree-Fock states by employing a modified Kuo interaction in (2p3/2,1f5/2,2p1/2,1g9/2) space. The DSM model has been quite successful in predicting many spectroscopic properties of N~Z medium heavy nuclei with A~64-80. The calculated β+/EC half-lives, for prolate and oblate shapes, compare well with the predictions of the calculations with Skyrme force by Sarriguren Going further, following recent searches, half-lives for 2ν β+β+/β+EC/ECEC decay for the nucleus Kr78 are calculated using DSM and the results compare well with QRPA predictions.

SU-E-J-109: Accurate Contour Transfer Between Different Image Modalities Using a Hybrid Deformable Image Registration and Fuzzy Connected Image Segmentation Method.

PubMed

Yang, C; Paulson, E; Li, X

2012-06-01

To develop and evaluate a tool that can improve the accuracy of contour transfer between different image modalities under challenging conditions of low image contrast and large image deformation, comparing to a few commonly used methods, for radiation treatment planning. The software tool includes the following steps and functionalities: (1) accepting input of images of different modalities, (2) converting existing contours on reference images (e.g., MRI) into delineated volumes and adjusting the intensity within the volumes to match target images (e.g., CT) intensity distribution for enhanced similarity metric, (3) registering reference and target images using appropriate deformable registration algorithms (e.g., B-spline, demons) and generate deformed contours, (4) mapping the deformed volumes on target images, calculating mean, variance, and center of mass as the initialization parameters for consecutive fuzzy connectedness (FC) image segmentation on target images, (5) generate affinity map from FC segmentation, (6) achieving final contours by modifying the deformed contours using the affinity map with a gradient distance weighting algorithm. The tool was tested with the CT and MR images of four pancreatic cancer patients acquired at the same respiration phase to minimize motion distortion. Dice's Coefficient was calculated against direct delineation on target image. Contours generated by various methods, including rigid transfer, auto-segmentation, deformable only transfer and proposed method, were compared. Fuzzy connected image segmentation needs careful parameter initialization and user involvement. Automatic contour transfer by multi-modality deformable registration leads up to 10% of accuracy improvement over the rigid transfer. Two extra proposed steps of adjusting intensity distribution and modifying the deformed contour with affinity map improve the transfer accuracy further to 14% averagely. Deformable image registration aided by contrast adjustment and fuzzy connectedness segmentation improves the contour transfer accuracy between multi-modality images, particularly with large deformation and low image contrast. © 2012 American Association of Physicists in Medicine.

A comparison of deformation and failure behaviors of AZ31 and E-form Mg alloys under V-bending test

NASA Astrophysics Data System (ADS)

Choi, Shi-Hoon; Singh, Jaiveer; Kim, Min-Seong; Yoon, Jeong-Whan

2016-08-01

Deformation and failure behaviors of magnesium (Mg) alloys (AZ31 and E-form) were investigated using V-bending test. Formability of these Mg alloys was discussed in terms of minimum bending radius. Microtexture evolution in the deformed Mg alloys was examined via electron back-scattered diffraction (EBSD) technique. Two level simulation technique which combined continuum finite element method (FEM) and crystal plasticity FEM successfully simulated the microtexture evolution in Mg alloys during V-bending test. The effect of deformation twinning on the failure in Mg alloys was also examined.

The Bloch equation with terms induced by an electric field

NASA Astrophysics Data System (ADS)

Garbacz, Piotr

2018-01-01

The Bloch equation of the nuclear magnetization of spin-1/2 nuclei in molecules, which have permanent electric dipole moments μe that are placed simultaneously in a magnetic field B and an electric field E, is derived. It is shown that if the principal components of the nuclear magnetic shielding tensor σ and the dipole moment μe are known, then the measurement of the transverse component to the magnetic field B of the nuclear magnetization, which is induced by the application of the electric field oscillating at the half of the spin precession frequency, allows determining the orientation of the dipole moment μe with respect to the principal axis system of the symmetric part of the tensor σ. Four-component relativistic density functional theory computations, which have been performed for several molecules containing heavy nuclei, i.e., 207Pb, 205Tl, 199Hg, 195Pt, and 125Te, indicate that coefficients of the relaxation matrix perturbed by the electric field E are in favorable cases of the order of 1000 pm2 V-2 T-2. Therefore, the spin dynamics is perturbed at experimentally observable levels for the strengths of electric and magnetic fields E = 5 kV/mm and B = 10 T, respectively.

Investigations of the structure and electromagnetic interactions of few body systems

NASA Astrophysics Data System (ADS)

Harper, E. P.; Lehman, D. R.; Prats, F.

The structure and electromagnetic interactions of few-body systems were investigated. The structural properties of the very light nuclei are examined by developing theoretical models that begin from the basic interactions between the constituents and that are solved exactly (numerically), i.e., full three- or four-body dynamics. Such models are then used in an attempt to understand the details of the strong and electromagnetic interactions of the few-nucleon nuclei after the basic underlying reaction mechanisms are understood with simpler models. Topics included: (1) set up the equations for the low-energy photodisintegration of (3)He and (3)H including final-state interactions and the E1 plus E2 operators; (2) develop a unified picture of the p + d (YIELDS) (3)He + (GAMMA), p + d (YIELDS) (3)He + (PI) (0), p + d (YIELDS) (3)H + (PI) (+) reactions at intermediate energies; (3) calculate the elastic and inelastic (1(+) (YIELDS) 0 (+)) form factors for (6)Li with three-body ((ALPHA)NN) wave functions; (4) calculate static properties (RMS radius, magnetic moment, and quadrupole moment) of (6)Li with three-body wave functions; and (5) develop the theory for the coincidence reactions (6)Li(p,2p)n(ALPHA), (6)Li(e,e'p)n(ALPHA), and (6)Li(e,e'd)(ALPHA).

[Morphologic changes in cultures of different tissues exposed to the toxins of C1. perfringens types B, C, E and F].

PubMed

Ermakova, M P; Zemlianitskaia, E P

1975-11-01

There were revealed morphological peculiarities of the action of C1. perfringens toxins, types B, C, D, E and F on the cultures of fibroblasts of chick embryo, amniotic cells and intestinal tissue. The toxin type B was characterized by a marked vocuolization of the cell cytoplasm; the action of the toxin of type C was expressed in the swelling of the nuclei and the lysis of the chromatine substance, the toxin of type E casued kariorhexis, and the toxin of type F--hyperchromatosis of the nuclei. All the cultures proved to be insensitive to the toxin of type D. Peculiarity of the morphological affection of the cells permitted to differentiate toxin of type B in the cultures of the fibroblasts of chick embryo, whereas the toxins of types C, E and F--in the cultures of the amniotic cells under control of the reaction of neutralization with the homologous antitoxic sera.

Coulomb-nuclear interference with {sup 6}Li: Isospin character of the 2{sub 1}{sup +} excitation in {sup 70,72,74}Ge

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barbosa, M.D.L.; Borello-Lewin, T.; Horodynski-Matsushigue, L.B.

2005-02-01

Ratios of B(E2) to B(IS2), that is, of the reduced quadrupole transition probabilities related, respectively, to charge and mass were extracted through Coulomb-nuclear interference (CNI) for the excitation of the 2{sub 1}{sup +} states in {sup 70,72,74}Ge, with a relative accuracy of less than 4%. For this purpose, the CNI angular distributions associated with the inelastic scattering of 28-MeV incident {sup 6}Li ions accelerated by the Sao Paulo Pelletron, and momentum analyzed by the Enge magnetic spectrograph were interpreted within the DWBA-DOMP approach (distorted wave approximation for the scattering process and deformed optical model for the structure representation) with globalmore » {sup 6}Li optical parameters. The present CNI results demonstrate an abrupt change in the B(E2)/B(IS2) ratio for {sup 74}Ge: although for {sup 70,72}Ge, values of the order of 1.0 or slightly higher were obtained, this ratio is 0.66 (7) for {sup 74}Ge. The heavier Ge isotope is thus one of the few nuclei that, so far, have been shown to present clear mixed symmetry components in their ground-state band.« less

Evidence for higher order QED effects in e+ e- pair production at the BNL Relativistic Heavy Ion Collider.

PubMed

Baltz, A J

2008-02-15

A new lowest order QED calculation for BNL Relativistic Heavy-Ion Collider e+ e- pair production has been carried out with a phenomenological treatment of the Coulomb dissociation of the heavy-ion nuclei observed in the STAR ZDC triggers. The lowest order QED result for the experimental acceptance is nearly 2 standard deviations larger than the STAR data. A corresponding higher-order QED calculation is consistent with the data.

CRPropa 2.0 - A public framework for propagating high energy nuclei, secondary gamma rays and neutrinos

NASA Astrophysics Data System (ADS)

Kampert, Karl-Heinz; Kulbartz, Jörg; Maccione, Luca; Nierstenhoefer, Nils; Schiffer, Peter; Sigl, Günter; van Vliet, Arjen René

2013-02-01

Version 2.0 of CRPropa [CRPropa is published under the 3rd version of the GNU General Public License (GPLv3). It is available, together with a detailed documentation of the code, at https://crpropa.desy.de.] is public software to model the extra-galactic propagation of ultra-high energy nuclei of atomic number Z⩽26 through structured magnetic fields and ambient photon backgrounds taking into account all relevant particle interactions. CRPropa covers the energy range 7×1016

Electrohydrodynamics of a viscous drop with inertia.

PubMed

Nganguia, H; Young, Y-N; Layton, A T; Lai, M-C; Hu, W-F

2016-05-01

Most of the existing numerical and theoretical investigations on the electrohydrodynamics of a viscous drop have focused on the creeping Stokes flow regime, where nonlinear inertia effects are neglected. In this work we study the inertia effects on the electrodeformation of a viscous drop under a DC electric field using a novel second-order immersed interface method. The inertia effects are quantified by the Ohnesorge number Oh, and the electric field is characterized by an electric capillary number Ca_{E}. Below the critical Ca_{E}, small to moderate electric field strength gives rise to steady equilibrium drop shapes. We found that, at a fixed Ca_{E}, inertia effects induce larger deformation for an oblate drop than a prolate drop, consistent with previous results in the literature. Moreover, our simulations results indicate that inertia effects on the equilibrium drop deformation are dictated by the direction of normal electric stress on the drop interface: Larger drop deformation is found when the normal electric stress points outward, and smaller drop deformation is found otherwise. To our knowledge, such inertia effects on the equilibrium drop deformation has not been reported in the literature. Above the critical Ca_{E}, no steady equilibrium drop deformation can be found, and often the drop breaks up into a number of daughter droplets. In particular, our Navier-Stokes simulations show that, for the parameters we use, (1) daughter droplets are larger in the presence of inertia, (2) the drop deformation evolves more rapidly compared to creeping flow, and (3) complex distribution of electric stresses for drops with inertia effects. Our results suggest that normal electric pressure may be a useful tool in predicting drop pinch-off in oblate deformations.

Active Galactic Nuclei

NASA Technical Reports Server (NTRS)

Mushotzky, Richard

2004-01-01

In the last 5 years the first high quality moderate resolution spectra of AGN in the x-ray band have become available thanks to the gratings on Chandra and XMM. Next year this type of data will be extended to E > 3 keV with the launch of Astro-E2. I will summarize some of the outstanding results from these new data and what we may expect from Astro-E2.

HPV E6/E7 RNA in situ hybridization signal patterns as biomarkers of three-tier cervical intraepithelial neoplasia grade.

PubMed

Evans, Mark F; Peng, Zhihua; Clark, Kelli M; Adamson, Christine S-C; Ma, Xiao-Jun; Wu, Xingyong; Wang, Hongwei; Luo, Yuling; Cooper, Kumarasen

2014-01-01

Cervical lesion grading is critical for effective patient management. A three-tier classification (cervical intraepithelial neoplasia [CIN] grade 1, 2 or 3) based on H&E slide review is widely used. However, for reasons of considerable inter-observer variation in CIN grade assignment and for want of a biomarker validating a three-fold stratification, CAP-ASCCP LAST consensus guidelines recommend a two-tier system: low- or high-grade squamous intraepithelial lesions (LSIL or HSIL). In this study, high-risk HPV E6/E7 and p16 mRNA expression patterns in eighty-six CIN lesions were investigated by RNAscope chromogenic in situ hybridization (CISH). Specimens were also screened by immunohistochemistry for p16INK4a (clone E6H4), and by tyramide-based CISH for HPV DNA. HPV genotyping was performed by GP5+/6+ PCR combined with cycle-sequencing. Abundant high-risk HPV RNA CISH signals were detected in 26/32 (81.3%) CIN 1, 22/22 (100%) CIN 2 and in 32/32 (100%) CIN 3 lesions. CIN 1 staining patterns were typified (67.7% specimens) by abundant diffusely staining nuclei in the upper epithelial layers; CIN 2 lesions mostly (66.7%) showed a combination of superficial diffuse-stained nuclei and multiple dot-like nuclear and cytoplasmic signals throughout the epithelium; CIN 3 lesions were characterized (87.5%) by multiple dot-like nuclear and cytoplasmic signals throughout the epithelial thickness and absence/scarcity of diffusely staining nuclei (trend across CIN grades: P<0.0001). These data are consistent with productive phase HPV infections exemplifying CIN 1, transformative phase infections CIN 3, whereas CIN 2 shows both productive and transformative phase elements. Three-tier data correlation was not found for the other assays examined. The dual discernment of diffuse and/or dot-like signals together with the assay's high sensitivity for HPV support the use of HPV E6/E7 RNA CISH as an adjunct test for deciding lesion grade when CIN 2 grading may be beneficial (e.g. among young women) or when 'LSIL vs. HSIL' assignment is equivocal.

HPV E6/E7 RNA In Situ Hybridization Signal Patterns as Biomarkers of Three-Tier Cervical Intraepithelial Neoplasia Grade

PubMed Central

Evans, Mark F.; Peng, Zhihua; Clark, Kelli M.; Adamson, Christine S.-C.; Ma, Xiao-Jun; Wu, Xingyong; Wang, Hongwei; Luo, Yuling; Cooper, Kumarasen

2014-01-01

Cervical lesion grading is critical for effective patient management. A three-tier classification (cervical intraepithelial neoplasia [CIN] grade 1, 2 or 3) based on H&E slide review is widely used. However, for reasons of considerable inter-observer variation in CIN grade assignment and for want of a biomarker validating a three-fold stratification, CAP-ASCCP LAST consensus guidelines recommend a two-tier system: low- or high-grade squamous intraepithelial lesions (LSIL or HSIL). In this study, high-risk HPV E6/E7 and p16 mRNA expression patterns in eighty-six CIN lesions were investigated by RNAscope chromogenic in situ hybridization (CISH). Specimens were also screened by immunohistochemistry for p16INK4a (clone E6H4), and by tyramide-based CISH for HPV DNA. HPV genotyping was performed by GP5+/6+ PCR combined with cycle-sequencing. Abundant high-risk HPV RNA CISH signals were detected in 26/32 (81.3%) CIN 1, 22/22 (100%) CIN 2 and in 32/32 (100%) CIN 3 lesions. CIN 1 staining patterns were typified (67.7% specimens) by abundant diffusely staining nuclei in the upper epithelial layers; CIN 2 lesions mostly (66.7%) showed a combination of superficial diffuse-stained nuclei and multiple dot-like nuclear and cytoplasmic signals throughout the epithelium; CIN 3 lesions were characterized (87.5%) by multiple dot-like nuclear and cytoplasmic signals throughout the epithelial thickness and absence/scarcity of diffusely staining nuclei (trend across CIN grades: P<0.0001). These data are consistent with productive phase HPV infections exemplifying CIN 1, transformative phase infections CIN 3, whereas CIN 2 shows both productive and transformative phase elements. Three-tier data correlation was not found for the other assays examined. The dual discernment of diffuse and/or dot-like signals together with the assay’s high sensitivity for HPV support the use of HPV E6/E7 RNA CISH as an adjunct test for deciding lesion grade when CIN 2 grading may be beneficial (e.g. among young women) or when ‘LSIL vs. HSIL’ assignment is equivocal. PMID:24625757

Triple Differential Cross Sections for single ionization of the Ethane molecule

NASA Astrophysics Data System (ADS)

Ali, Esam; Nixon, Kate; Ning, Chuangang; Murray, Andrew; Madison, Don

2015-09-01

We report experimental and theoretical results for electron-impact (e,2e) ionization of the Ethane molecule (C2H6) in the coplanar scattering geometry for four different ejected electron energies Ea = 5,10,15, and 20 eV respectively, and for each ejected electron energy, the projectile scattering angle is fixed at 10°. We will show that the TDCS is very sensitive for the case of two heavy nuclei surrounded by lighter H nuclei. On the theoretical side, we have used the M3DW coupled with the Orientation Averaged Molecular Orbital (OAMO) approximation and proper average (PA) over all orientations. These approximations show good agreement with experimental data for the binary peaks. However, for the recoil peak region, experiment finds a noticeable peak while theory predicts no peak. No recoil peak suggests no (or very weak) nuclear scattering, so we have investigated the importance of nuclear scattering by moving the nuclei closer to the center of mass. This work is supported by the US National Science Foundation under Grant No. PHY-1068237 and XSEDE resources provided by the Texas Advanced Computing Center (Grant No. TG-MCA07S029).

Direct observation of nucleation in the bulk of an opaque sample

DOE PAGES

Xu, Chaoling; Zhang, Yubin; Godfrey, Andrew; ...

2017-02-14

Remarkably little is known about the physical phenomena leading to nucleation of new perfect crystals within deformed metals during annealing, in particular how and where volumes with nearly perfect lattices evolve from structures filled with dislocations, and how local variations at the micrometer length scale affect this nucleation process. We present here the first experimental measurements that relate directly nucleation of recrystallization to the local deformation microstructure in the bulk of a sample of cold rolled aluminum, further deformed locally by a hardness indentation. White beam differential aperture X-ray microscopy is used for the measurements, allowing us to map amore » selected gauge volume in the bulk of the sample in the deformed state, then anneal the sample and map the exact same gauge volume in the annealed state. It is found that nuclei develop at sites of high stored energy and they have crystallographic orientations from those present in the deformed state. Accordingly we suggest that for each nucleus the embryonic volume arises from a structural element contained within the voxels identified with the same orientation. In conclusion, possible nucleation mechanisms are discussed and the growth potentials of the nuclei are also analyzed and discussed.« less

Direct observation of nucleation in the bulk of an opaque sample.

PubMed

Xu, Chaoling; Zhang, Yubin; Godfrey, Andrew; Wu, Guilin; Liu, Wenjun; Tischler, Jonathan Z; Liu, Qing; Juul Jensen, Dorte

2017-02-14

Remarkably little is known about the physical phenomena leading to nucleation of new perfect crystals within deformed metals during annealing, in particular how and where volumes with nearly perfect lattices evolve from structures filled with dislocations, and how local variations at the micrometer length scale affect this nucleation process. We present here the first experimental measurements that relate directly nucleation of recrystallization to the local deformation microstructure in the bulk of a sample of cold rolled aluminum, further deformed locally by a hardness indentation. White beam differential aperture X-ray microscopy is used for the measurements, allowing us to map a selected gauge volume in the bulk of the sample in the deformed state, then anneal the sample and map the exact same gauge volume in the annealed state. It is found that nuclei develop at sites of high stored energy and they have crystallographic orientations from those present in the deformed state. Accordingly we suggest that for each nucleus the embryonic volume arises from a structural element contained within the voxels identified with the same orientation. Possible nucleation mechanisms are discussed and the growth potentials of the nuclei are also analyzed and discussed.

An optical potential for the statically deformed actinide nuclei derived from a global spherical potential

NASA Astrophysics Data System (ADS)

Al-Rawashdeh, S. M.; Jaghoub, M. I.

2018-04-01

In this work we test the hypothesis that a properly deformed spherical optical potential, used within a channel-coupling scheme, provides a good description for the scattering data corresponding to neutron induced reactions on the heavy, statically deformed actinides and other lighter deformed nuclei. To accomplish our goal, we have deformed the Koning-Delaroche spherical global potential and then used it in a channel-coupling scheme. The ground-state is coupled to a sufficient number of inelastic rotational channels belonging to the ground-state band to ensure convergence. The predicted total cross sections, elastic and inelastic angular distributions are in good agreement with the experimental data. As a further test, we compare our results to those obtained by a global channel-coupled optical model whose parameters were obtained by fitting elastic and inelastic angular distributions in addition to total cross sections. Our results compare quite well with those obtained by the fitted, channel-coupled optical model. Below neutron incident energies of about 1MeV, our results show that scattering into the rotational excited states of the ground-state band plays a significant role in the scattering process and must be explicitly accounted for using a channel-coupling scheme.

Comet Wild 2 and the two kinds of cometary sub-nuclei population

NASA Astrophysics Data System (ADS)

Illes-Almar, E.

On the 2nd January 2004 Stardust encountered the nucleus of comet Wild 2 by 240 km. 72 images have been collected - among them the up-till-now best views of a cometary nucleus. The "pockmarked" surface of the comet is peculiar as the "craters" are not normal craters: neither in shape nor in cross section. Their shapes are rather irregular and generally not central or axisymmetric. Furthermore they have flat bottoms and very steep walls that seem almost perpendicular to the surface. One has the feeling that they are not impact craters. In the framework of our `two kinds of cometary sub-nuclei population' hypothesis (Illés-Almár, 1995, 2002) the cavities can be explained by the stronger sublimation where the loose sub-nuclei are exposed to the surface. The almost vertical walls resemble to the vertical walls of the sublimated CO2 ice on the South polar cap of Mars. References: Illés-Almár, E.: On two different populations of cometary sub-nuclei. Antarctic Meteorites XX. June 6-8, 1995, Tokyo. Abstracts pp. 93-94, 1995. Illés-Almár, E.: Comet Borrelly and the two kinds of cometary sub-nuclei population. (submitted to Adv. Sp. Res. in 2002)

Computational efficient segmentation of cell nuclei in 2D and 3D fluorescent micrographs

NASA Astrophysics Data System (ADS)

De Vylder, Jonas; Philips, Wilfried

2011-02-01

This paper proposes a new segmentation technique developed for the segmentation of cell nuclei in both 2D and 3D fluorescent micrographs. The proposed method can deal with both blurred edges as with touching nuclei. Using a dual scan line algorithm its both memory as computational efficient, making it interesting for the analysis of images coming from high throughput systems or the analysis of 3D microscopic images. Experiments show good results, i.e. recall of over 0.98.

Plate tectonics beyond plate boundaries: the role of ancient structures in intraplate orogenesis

NASA Astrophysics Data System (ADS)

Heron, Philip; Pysklywec, Russell; Stephenson, Randell

2015-04-01

The development of orogens that occur at a distance from plate boundaries (i.e., `intraplate' deformation) cannot be adequately explained through conventional plate tectonic theory. Intraplate deformation infers a more complex argument for lithospheric and mantle interaction than plate tectonic theory allows. As a result, the origins of intraplate orogenesis are enigmatic. One hypothesis is the amalgamation of continental material (i.e., micro-plates) leaves inherent scars on the crust and mantle lithosphere. Previous studies into continent-continent collisions identify a number of scenarios from accretionary tectonics that affect the crust and mantle (namely, the development of a Rayleigh-Taylor instability, lithospheric underplating, lithospheric delamination, and lithospheric subduction). Any of these processes may weaken the lithosphere allowing episodic reactivation of faults within continental interiors. Hence, continental convergence (i.e., shortening) at a time after continental collision may cause the already weakened crust and mantle lithosphere to produce intraplate deformation. In order to better understand the processes involved in deformation away from plate boundaries, we present suites of continental shortening models (using the high-resolution thermal-mechanical modelling code SOPALE) to identify the preferred style of deformation. We model ancient structures by applying weak subduction scarring, changing the rheological conditions, and modifying the thermal structure within the lithosphere. To highlight the role of surface processes on plate and lithosphere deformation, the effect of climate-driven erosion and deposition on the tectonic structure of intraplate deformation is also addressed. We explore the relevance of the models to previously studied regions of intraplate orogenesis, including the Pyrenees in Europe, the Laramide orogen in North America, Tien Shan orogen in Central Asia, and Central Australia. The findings of the simulations with regards to past and future North American intraplate deformation are also discussed. Our results indicate that there exists a number of tectonic environments that can be produced relating to continental accretion, and that specific observational constraints to the local area (e.g., geological, geophysical, geodetic) are required to be integrated directly into the analyses for better interpretation. The models shown here find that although rheological changes to the lithosphere can produce a range of deformation during continental convergence (i.e., crustal thickening, thinning, and folding), mantle weak zones from ancient subduction can generate more localized deformation and topography.

Feasibility of observing the α decay chains from isotopes of SHN with Z = 128, Z = 126, Z = 124 and Z = 122

NASA Astrophysics Data System (ADS)

Santhosh, K. P.; Priyanka, B.; Nithya, C.

2016-11-01

Within the Coulomb and proximity potential model for deformed nuclei (CPPMDN), the alpha decay properties of 34 isotopes of the superheavy nuclei with Z = 128 within the range 306 ≤ A ≤ 339 have been studied, considering both the parent and daughter nuclei to be deformed. The manuscript also deals with the decay properties of the isotopes of Z = 126 (within 288 ≤ A ≤ 339), Z = 124 (within 284 ≤ A ≤ 339) and Z = 122 (within 280 ≤ A ≤ 339). The alpha decay half lives thus evaluated have been compared with the values evaluated using other theoretical models and it was seen that, our theoretical alpha decay half lives match well with these values. Through the present study, we have underlined and have established the fact that, among the 192 isotopes considered in the present study, only those isotopes 321-324,328-335128, 318-320,323-327126, 305-308,315-322124 and 298-307,311-314122 can be synthesised and detected through alpha decay in laboratory. As the alpha decay half lives of these superheavy isotopes lie within the experimental limits, we hope these predictions, on the decay modes of these unknown nuclei, to pave the way for the future experiments. The proton separation energy calculations on 306-339128, 288-336126, 284-339124 and 280-339122 superheavy nuclei have also been done and the study revealed the probable proton emitters among these nuclei.

Nuclear spectroscopy of doubly-even130,132Ba

NASA Astrophysics Data System (ADS)

Gupta, Anuradha; Gupta, Surbhi; Singh, Suram; Bharti, Arun

2018-05-01

A comparative study of some high-spin characteristic nuclear structure properties of doubly-even 130,132Ba nuclei has been made using two microscopic frameworks - CHFB and PSM. The yrast spectra, intrinsic quadrupole moment and deformation systematics of these nuclei have been successfully calculated. Further, the calculated data from both the frameworks is also compared with the available experimental data and a good agreement has been obtained. The present CHFB calculations describes very well the low spin structure of even-even 130,132Ba nuclei whereas PSM calculations provide a qualitative description of the high-spin band structure of doubly-even 130,132Ba nuclei.

Proceedings of the international conference on nuclear physics, August 24-30, 1980, Berkeley, California. Volume 1. Abstracts. [Berkeley, California, August 24-30, 1980 (abstracts only)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1980-01-01

This volume contains all abstracts (931) received by the conference organizers before June 20, 1980. The abstracts are grouped according to the following topics: nucleon-nucleon interactions, free and in nuclei; distribution of matter, charge, and magnetism; exotic nuclei and exotic probes; giant resonances and other high-lying excitations; applications of nuclear science; nuclei with large angular momentum and deformation; heavy-ion reactions and relaxation phenomena; new techniques and instruments; pion absorption and scattering by nuclei; and miscellaneous. Some of these one-page abstracts contain data. A complete author index is provided. (RWR)

Description of the Hexadecapole Deformation Parameter in the sdg Interacting Boson Model

NASA Astrophysics Data System (ADS)

Liu, Yu-xin; Sun, Di; Wang, Jia-jun; Han, Qi-zhi

1998-04-01

The hexadecapole deformation parameter β4 of the rare-earth and actinide nuclei is investigated in the framework of the sdg interacing boson model. An explicit relation between the geometric hexadecapole deformation parameter β4 and the intrinsic deformation parameters epsilon4, epsilon2 are obtained. The deformation parameters β4 of the rare-earths and actinides are determined without any free parameter. The calculated results agree with experimental data well. It also shows that the SU(5) limit of the sdg interacting boson model can describe the β4 systematics as well as the SU(3) limit.

Ultrasound-induced oscillations of gas bubbles in contact with gelatin gel surfaces

NASA Astrophysics Data System (ADS)

Fukui, Sosuke; Ando, Keita

2017-11-01

Ultrasound-induced dynamics of gas bubbles in the vicinity of deformable boundaries are studied experimentally, as a simplified model of sonoporation in medicine. In our experiment, 28-kHz underwater ultrasound was irradiated to a gas bubble nuclei (of radius from 60 μm to 200 μm) sitting at gel surfaces (of gelatin concentration from 6 wt% to 16 wt%) and the bubble dynamics were recorded by a high-speed camera. The repeated deformation of the gel surface was found to be in phase with volumetric oscillation of the bubble. A liquid jet, which can appear toward the collapse phase in the bubble oscillation in volume, produced localized surface deformation, which is an important observation in the context of sonoporation. We characterize the maximum displacement of the gel surface with varying the bubble nuclei radius (in comparison to the resonant radius fixed approximately at 117 μm). We also examine the phase difference between the ultrasound and the bubble dynamics under the influence of the deformable boundary. The Research Grant of Keio Leading-edge Laboratory of Science & Technology.

Systematization of α-decaying nuclei based on shell structures: The case of odd-even and odd-odd nuclei

NASA Astrophysics Data System (ADS)

Yarman, Tolga; Zaim, Nimet; Yarman, Ozan; Kholmetskii, Alexander; Arık, Metin

In previous studies, we provided a novel systematization of α-decaying even-even and even-odd nuclei starting with the classically adopted mechanism [T. Yarman et al., Eur. Phys. J. A 52 (2016) 140; Eur. Phys. J. A 53 (2017) 4]. Knowing beforehand the measured decay half-life, we had taken as a parameter the probability of the α-particle as being first born in a unit period of time, within the parent nucleus before it is emitted out. We thence developed a scaffold based on shell properties of families composed of “alike nuclei”. Along the same line, we now present a systematization of odd-even (OE) as well as odd-odd (OO) nuclei. We apply our approach further to the investigation of the effect of pairing (e.g., the effect when the number of nucleons is increased by one neutron), and that of unpairing (e.g., the effect when the number of nucleons is decreased by one neutron); thus it becomes an even number for the case of odd-even nuclei (Case OE), and an odd number in the case of odd-odd nuclei (Case OO). For the first case (OE), we pick the exemplar set 161Re, 217Fr, 243Bk, 263Db; where we delineate by, respectively, Re, Fr, Bk, and Db all of the odd-even or odd-odd isotopes that neighbor the four mentioned odd-even isotopes on the proposed scaffold. We proceed in the same way for the second case (OO). Thus, we choose the exemplar set of odd-odd nuclei 172Ir, 218Ac, 244Es. We then gather all of the Ir, Ac, and Es odd-odd and odd-even isotopes that neighbor the three mentioned odd-odd isotopes on the proposed scaffold. We show that, in the former case, pairing, as expected, generally increases stability of the given nucleus; and in the latter case, unpairing works in just the opposite direction — i.e., it generally increases instability. We disclose “stability peaks” versus Z for both sets of nuclei, we tackle here. Furthermore, we present a study to highlight an outlook of “odd-A nuclei” at hand. Contrary to the general expectation, we unveil no systematic on that.

Foldover-free shape deformation for biomedicine.

PubMed

Yu, Hongchuan; Zhang, Jian J; Lee, Tong-Yee

2014-04-01

Shape deformation as a fundamental geometric operation underpins a wide range of applications, from geometric modelling, medical imaging to biomechanics. In medical imaging, for example, to quantify the difference between two corresponding images, 2D or 3D, one needs to find the deformation between both images. However, such deformations, particularly deforming complex volume datasets, are prone to the problem of foldover, i.e. during deformation, the required property of one-to-one mapping no longer holds for some points. Despite numerous research efforts, the construction of a mathematically robust foldover-free solution subject to positional constraints remains open. In this paper, we address this challenge by developing a radial basis function-based deformation method. In particular we formulate an effective iterative mechanism which ensures the foldover-free property is satisfied all the time. The experimental results suggest that the resulting deformations meet the internal positional constraints. In addition to radial basis functions, this iterative mechanism can also be incorporated into other deformation approaches, e.g. B-spline based FFDs, to develop different deformable approaches for various applications. Crown Copyright © 2013. Published by Elsevier Inc. All rights reserved.

Microscopic time-dependent analysis of neutrons transfers at low-energy nuclear reactions with spherical and deformed nuclei

NASA Astrophysics Data System (ADS)

Samarin, Viacheslav

2014-03-01

Time-dependent Schrödinger equation is numerically solved by difference method for external neutrons of nuclei 6He, 18O, 48Са, 238U at their grazing collisions with energies in the vicinity of a Coulomb barrier. The spin-orbital interaction and Pauli's exclusion principle were taken into consideration during the solution.

The role of seniority-zero states in nuclear level densities

DOE PAGES

Åberg, S.; Carlsson, B. G.; Døssing, Th.; ...

2015-06-01

At low excitation energies seniority-zero states dominate the level density of K=0 bands in deformed even–even nuclei, while they play no role at higher excitation energies. We describe the level densities in a Fermi-gas model as well as in a combinatorial level-density model and compare to detailed experimental data for some rare-earth nuclei.

eEF1A Controls ascospore differentiation through elevated accuracy, but controls longevity and fruiting body formation through another mechanism in Podospora anserina.

PubMed Central

Silar, P; Lalucque, H; Haedens, V; Zickler, D; Picard, M

2001-01-01

Antisuppressor mutations in the eEF1A gene of Podospora anserina were previously shown to impair ascospore formation, to drastically increase life span, and to permit the development of the Crippled Growth degenerative process. Here, we show that eEF1A controls ascospore formation through accuracy level maintenance. Examination of antisuppressor mutant perithecia reveals two main cytological defects, mislocalization of spindle and nuclei and nuclear death. Antisuppression levels are shown to be highly dependent upon both the mutation site and the suppressor used, precluding any correlation between antisuppression efficiency and severity of the sporulation impairment. Nevertheless, severity of ascospore differentiation defect is correlated with resistance to paromomycin. We also show that eEF1A controls fruiting body formation and longevity through a mechanism(s) different from accuracy control. In vivo, GFP tagging of the protein in a way that partly retains its function confirmed earlier cytological observation; i.e., this factor is mainly diffuse within the cytosol, but may transiently accumulate within nuclei or in defined regions of the cytoplasm. These data emphasize the fact that the translation apparatus exerts a global regulatory control over cell physiology and that eEF1A is one of the key factors involved in this monitoring. PMID:11514440

Critical insights into nuclear collectivity from complementary nuclear spectroscopic methods

NASA Astrophysics Data System (ADS)

Garrett, P. E.; Wood, J. L.; Yates, S. W.

2018-06-01

Low-energy collectivity of nuclei has been, and is being, characterized in a critical manner using data from a variety of spectroscopic methods, including Coulomb excitation, β decay, inelastic scattering of charged and uncharged particles, transfer reactions, etc. In addition to level energies and spins, transition multipolarities and intensities, lifetimes, and nuclear moments are available. The totality of information from these probes must be considered in achieving an accurate vision of the excitations in nuclei and determining the applicability of nuclear models. From these data, major changes in our view of low-energy collectivity in nuclei have emerged; most notable is the demise of the long-held view of low-energy quadrupole collectivity near closed shells as due to vibrations about a spherical equilibrium shape. In this contribution, we focus on the basic predictions of the spherical harmonic vibrator limit of the Bohr Hamiltonian. Properties such as B(E2) values, quadrupole moments, E0 strengths, etc are outlined. Using the predicted properties as a guide, evidence is cited for and against the existence of vibrational states, and especially multi-phonon states, in nuclei that are, or historically were considered to be, spherical or have a nearly spherical shape in their ground state. It is found that very few of the nuclei that were identified in the last major survey seeking nearly spherical harmonic vibrators satisfy the more stringent guidelines presented herein. Details of these fundamental shifts in our view of low-energy collectivity in nuclei are presented.

In-beam spectroscopy of the k π=0- bands in230 236U

NASA Astrophysics Data System (ADS)

Zeyen, P.; Ackermann, B.; Dämmrich, U.; Euler, K.; Grafen, V.; Günther, C.; Herzog, P.; Marten-Tölle, M.; Prillwitz, B.; Tölle, R.; Lauterbach, Ch.; Maier, H. J.

1987-12-01

The K π=0- bands in even uranium nuclei were studied in the compound reactions231Pa( p, 2 n)230U,230, 232Th( α,2 n)232, 234U and236U( d, pn)236U. In-beam γ-rays were measured in coincidence with conversion-electrons, which were detected with an iron-free orange spectrometer. The negative-parity levels are observed up to intermediate spins ( I<13-). In addition, the 1- and 3- levels in230U were confirmed by a decay study with an isotope separated230Pa source. For the heavier isotopes ( A≥232) the properties of the K π=0- bands (energies and γ-branchings) are consistent with a vibrational character of these bands. For230U the K π=0- band lies at rather low energy ( E(1-)=367 keV), and the level spacings within this band are very similar to those of the isotones228Th and226Ra, which might indicate the onset of a stable octupole deformation.

Nilsson diagrams for light neutron-rich nuclei with weakly-bound neutrons

NASA Astrophysics Data System (ADS)

Hamamoto, Ikuko

2007-11-01

Using Woods-Saxon potentials and the eigenphase formalism for one-particle resonances, one-particle bound and resonant levels for neutrons as a function of quadrupole deformation are presented, which are supposed to be useful for the interpretation of spectroscopic properties of some light neutron-rich nuclei with weakly bound neutrons. Compared with Nilsson diagrams in textbooks that are constructed using modified oscillator potentials, we point out a systematic change of the shell structure in connection with both weakly bound and resonant one-particle levels related to small orbital angular momenta ℓ. Then, it is seen that weakly bound neutrons in nuclei such as C15-19 and Mg33-37 may prefer being deformed as a result of the Jahn-Teller effect, due to the near degeneracy of the 1d5/2-2s1/2 levels and the 1f7/2-2p3/2 levels in the spherical potential, respectively. Furthermore, the absence of some one-particle resonant levels compared with the Nilsson diagrams in textbooks is illustrated.

New K isomers in the neutron-rich N =100 isotones 162Sm, 163Eu, and 164Gd

NASA Astrophysics Data System (ADS)

Yokoyama, R.; Go, S.; Kameda, D.; Kubo, T.; Inabe, N.; Fukuda, N.; Takeda, H.; Suzuki, H.; Yoshida, K.; Kusaka, K.; Tanaka, K.; Yanagisawa, Y.; Ohtake, M.; Sato, H.; Shimizu, Y.; Baba, H.; Kurokawa, M.; Nishimura, D.; Ohnishi, T.; Iwasa, N.; Chiba, A.; Yamada, T.; Ideguchi, E.; Fujii, T.; Nishibata, H.; Ieki, K.; Murai, D.; Momota, S.; Sato, Y.; Hwang, J. W.; Kim, S.; Tarasov, O. B.; Morrissey, D. J.; Sherrill, B. M.; Simpson, G.; Praharaj, C. R.

2017-03-01

Very neutron-rich Z ˜60 isotopes produced by in-flight fission of a 345 MeV/nucleon 238U beam at the RI Beam Factory, RIKEN Nishina Center, have been studied by delayed γ -ray spectroscopy. New isomers were discovered in the neutron-rich N =100 isotones 162Sm, 163Eu, and 164Gd. Half-lives, γ -ray energies, and relative intensities of these isomers were obtained. Level schemes were proposed for these nuclei and the first 2+ and 4+ states were assigned for the even-even nuclei. The first 2+ and 4+ state energies decrease as the proton numbers get smaller. The energies and the half-lives of the new isomers are very similar to those of 4- isomers known in less neutron-rich N =100 isotones 168Er and 170Yb. A deformed Hartree-Fock with angular momentum projection model suggests Kπ=4- two-quasiparticle states with ν 7 /2 [633 ]⊗ν 1 /2 [521 ] configurations with similar excitation energy. The results suggest that neutron-rich N =100 nuclei are well deformed and the deformation gets larger as Z decreases to 62. The onset of K isomers with the same configuration at almost the same energy in N =100 isotones indicates that the neutron single-particle structures of neutron-rich isotones down to Z =62 do not change significantly from those of the Z =70 stable nuclei. Systematics of the excitation energies of new isomers can be explained without the predicted N =100 shell gap.

Multi-scale Investigation on Microstructure, Mechanical Properties, and Deformation Mechanisms in Mg Alloys

NASA Astrophysics Data System (ADS)

Zhang, Dalong

Mg and its alloys are promising candidates for light-weight structural applications, e.g., aircraft, automobile, electronic, etc. However, the inherent hexagonal close packed crystal structure makes the deformation of Mg anisotropic, namely deformation only occurs predominantly by dislocation slip in the close-packed (0001) plane (i.e., basal plane), or by deformation twinning in {101¯2} planes. Both basal slip and twinning cause the crystal to re-orient. Consequently, polycrystalline Mg alloys that have undergone thermomechanical processing usually contain strong texture, i.e., preferred crystallographic orientation in grains. The texture in turn leads to anisotropic deformation in wrought Mg alloys. For example, in extruded Mg alloys, the compressive yield strength is usually much lower than the tensile yield strength (so-called yield asymmetry and strength differential). It is the anisotropy that hinders the broader application of Mg alloys. Recent modeling studies on Mg predict that certain alloying elements, particularly rare-earth elements (e.g., Y, Ce, Nd, Gd, etc.), could alter the active deformation modes and enhance homogeneous deformation and overall mechanical properties in Mg. Therefore, the objective of this dissertation research is to investigate experimentally the effects of alloying element Y in reducing the intrinsic and extrinsic anisotropy, modifying texture, and enhancing the overall strength and ductility for Mg. In addition, the research also uncovered some unexpected "side effects" of Y and these phenomena were studied and explained from a fundamental perspective. The methodology used in this work is described as follows. Ultrafine grained Mg 2.5 at.% Y alloy (UFG Mg-2.5Y) was prepared by powder metallurgy method, including gas atomization for producing Mg-2.5Y powder, degassing and hot isostatic pressing (HIP), and hot extrusion. Both the as-HIPed and the as-extruded materials were characterized by electron back-scattered diffraction (EBSD), transmission electron microscopy (TEM), and/or atom probe tomography (APT). It is noted that different configurations of stacking faults (all in basal plane, i.e., basal stacking faults, BSFs for short) were observed in the as-extruded Mg-2.5Y, whereas no BSFs were documented in the as-HIPed alloy. Feasible models to explain the formation of BSFs were proposed based on the activity of different dislocations. Tension and compression tests were carried out along the extrusion direction (ED) for UFG Mg-2.5Y. Unlike common Mg alloys exhibiting yield asymmetry, the UFG Mg-2.5Y exhibits yield "symmetry" and significantly reduced strength differential. Namely, the deformation is more isotropic. In addition to post-mortem TEM characterization for deformed UFG Mg-2.5Y, in-situ TEM was also performed, in an effort to understand the fundamental deformation mechanisms in UFG Mg-Y that lead to reduced anisotropy. In-situ TEM for single-crystal Mg-Y nano-pillars reveals that deformation twinning is replaced by dislocation slip in non-basal planes (i.e., prismatic planes), which diametrically differs from any other Mg alloys. However, it is noted that deformation twinning still occurs in the polycrystalline UFG Mg-2.5Y occasionally, and a new type of stacking faults (i.e., prismatic stacking faults, PSFs for short) may be present in the vicinity of twins. Feasible mechanisms explaining the formation of PSFs are proposed.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Allmond, J. M.; Wood, J. L.

We extracted empirical moments of inertia, J1, J2, J3, of atomic nuclei with E(4more » $$+\\atop{1}$$)/E(2$$+\\atop{1}$$ ) > 2.7 from experimental 2$$+\\atop{g,y}$$, energies and electric quadrupole matrix elements, determined from multi- step Coulomb excitation data, and the results are compared to expectations based on rigid and irro- tational inertial flow. Only by having the signs of the E2 matrix elements, i.e., <2$$+\\atop{g}$$ ||M (E2)||2$$+\\atop{g}$$> and <0$$+\\atop{g}$$ ||M (E2)||2$$+\\atop{g}$$> < 2$$+\\atop{g}$$ ||M (E2)||2$$+\\atop{γ}$$> <2$$+\\atop{γ}$$ ||M (E2)||0$$+\\atop{g}$$> , can a unique solution to all three components of the inertia tensor of an asymmetric top be obtained. And while the absolute moments of inertia fall between the rigid and irrotational values as expected, the relative moments of inertia appear to be qualitatively consistent with the β 2 sin 2(γ ) dependence of the Bohr Hamiltonian which originates from a SO(5) in- variance. A better understanding of inertial flow is central to improving collective models, particularly hydrodynamic-based collective models. The results suggest that a better description of collective dynamics and inertial flow for atomic nuclei is needed. The inclusion of vorticity degrees of freedom may provide a path forward. This is our first report of empirical moments of inertia for all three axes and the results should challenge both collective and microscopic descriptions of inertial flow.« less

Energy spectrum inverse problem of q-deformed harmonic oscillator and entanglement of composite bosons

NASA Astrophysics Data System (ADS)

Sang, Nguyen Anh; Thu Thuy, Do Thi; Loan, Nguyen Thi Ha; Lan, Nguyen Tri; Viet, Nguyen Ai

2017-06-01

Using the simple deformed three-level model (D3L model) proposed in our early work, we study the entanglement problem of composite bosons. Consider three first energy levels are known, we can get two energy separations, and can define the level deformation parameter δ. Using connection between q-deformed harmonic oscillator and Morse-like anharmonic potential, the deform parameter q also can be derived explicitly. Like the Einstein’s theory of special relativity, we introduce the observer e˙ects: out side observer (looking from outside the studying system) and inside observer (looking inside the studying system). Corresponding to those observers, the outside entanglement entropy and inside entanglement entropy will be defined.. Like the case of Foucault pendulum in the problem of Earth rotation, our deformation energy level investigation might be useful in prediction the environment e˙ect outside a confined box.

A New Insight into Neutrino Energy Loss by Electron Capture of Iron Group Nuclei in Magnetar Surfaces

NASA Astrophysics Data System (ADS)

Liu, Jing-Jing; Gu, Wei-Min

2016-06-01

Based on the relativistic mean-field effective interactions theory, and the Lai dong model, we discuss the influences of superstrong magnetic fields (SMFs) on electron Fermi energy, nuclear blinding energy, and single-particle level structure in magnetar surfaces. Using the Shell-Model Monte Carlo method and the Random Phase Approximation theory, we analyze the neutrino energy loss rates (NELRs) by electron capture for iron group nuclei in SMFs. First, when B 12 < 100, we find that the SMFs have a slight influence on the NELRs for most nuclides at relativistic low temperatures (e.g., T 9 = 0.233); nevertheless, the NELRs increase by more than four orders of magnitude at relativistic high temperatures (e.g., T 9 = 15.53). When B 12 > 100, the NELRs decrease by more than three orders of magnitude (e.g., at T 9 = 15.53 for 52-61Fe, 55-60Co, and 56-63Ni). Second, for a certain value of magnetic field and temperature, the NELRs increase by more than four orders of magnitude when {ρ }7≤slant {10}3, but as the density increases (I.e., when {ρ }7\\gt {10}3), there is almost no influence on the density of NELRs. For the density around {ρ }7={10}2, there is an abrupt increase in NELRs when B 12 ≥ 103.5. Such jumps are an indication that the underlying shell structure has changed due to single-particle behavior by SMFs. Finally, we compare our NELRs with those of Fuller et al. (FFN) and Nabi & Klapdor-Kleingrothaus (NKK). For the case without SMFs, one finds that our rates for certain nuclei are close to about five orders of magnitude lower than FFN and NKK at relativistic low temperatures (e.g., T 9 = 1). However, at a relativistic high temperature (e.g., T 9 = 3), our results are in good agreement with NKK, but about one order of magnitude lower than FFN. For the case with SMFs, our NELRs for some iron group nuclei can be about five orders of magnitude higher than those of FFN and NKK. (Note that B 12, T 9, and ρ 7 are in units of 1012 G, 109 K, and {10}7 {{g}} {{cm}}-3, respectively.)

Skin surface and sub-surface strain and deformation imaging using optical coherence tomography and digital image correlation

NASA Astrophysics Data System (ADS)

Hu, X.; Maiti, R.; Liu, X.; Gerhardt, L. C.; Lee, Z. S.; Byers, R.; Franklin, S. E.; Lewis, R.; Matcher, S. J.; Carré, M. J.

2016-03-01

Bio-mechanical properties of the human skin deformed by external forces at difference skin/material interfaces attract much attention in medical research. For instance, such properties are important design factors when one designs a healthcare device, i.e., the device might be applied directly at skin/device interfaces. In this paper, we investigated the bio-mechanical properties, i.e., surface strain, morphological changes of the skin layers, etc., of the human finger-pad and forearm skin as a function of applied pressure by utilizing two non-invasive techniques, i.e., optical coherence tomography (OCT) and digital image correlation (DIC). Skin deformation results of the human finger-pad and forearm skin were obtained while pressed against a transparent optical glass plate under the action of 0.5-24 N force and stretching naturally from 90° flexion to 180° full extension respectively. The obtained OCT images showed the deformation results beneath the skin surface, however, DIC images gave overall information of strain at the surface.

The discovery of a conjugate system of faults in the Wharton Basin intraplate deformation zone

PubMed Central

Singh, Satish C.; Hananto, Nugroho; Qin, Yanfang; Leclerc, Frederique; Avianto, Praditya; Tapponnier, Paul E.; Carton, Helene; Wei, Shengji; Nugroho, Adam B.; Gemilang, Wishnu A.; Sieh, Kerry; Barbot, Sylvain

2017-01-01

The deformation at well-defined, narrow plate boundaries depends on the relative plate motion, but how the deformation takes place within a distributed plate boundary zone remains a conundrum. This was confirmed by the seismological analyses of the 2012 great Wharton Basin earthquakes [moment magnitude (Mw) 8.6], which suggested the rupture of several faults at high angles to one another. Using high-resolution bathymetry and seismic reflection data, we report the discovery of new N294°E-striking shear zones, oblique to the plate fabric. These shear zones are expressed by sets of normal faults striking at N335°E, defining the direction of the principal compressional stress in the region. Also, we have imaged left-lateral strike-slip faults along reactivated N7°E-oriented oceanic fracture zones. The shear zones and the reactivated fracture zones form a conjugate system of faults, which accommodate present-day intraplate deformation in the Wharton Basin. PMID:28070561

The discovery of a conjugate system of faults in the Wharton Basin intraplate deformation zone.

PubMed

Singh, Satish C; Hananto, Nugroho; Qin, Yanfang; Leclerc, Frederique; Avianto, Praditya; Tapponnier, Paul E; Carton, Helene; Wei, Shengji; Nugroho, Adam B; Gemilang, Wishnu A; Sieh, Kerry; Barbot, Sylvain

2017-01-01

The deformation at well-defined, narrow plate boundaries depends on the relative plate motion, but how the deformation takes place within a distributed plate boundary zone remains a conundrum. This was confirmed by the seismological analyses of the 2012 great Wharton Basin earthquakes [moment magnitude ( M w ) 8.6], which suggested the rupture of several faults at high angles to one another. Using high-resolution bathymetry and seismic reflection data, we report the discovery of new N294°E-striking shear zones, oblique to the plate fabric. These shear zones are expressed by sets of normal faults striking at N335°E, defining the direction of the principal compressional stress in the region. Also, we have imaged left-lateral strike-slip faults along reactivated N7°E-oriented oceanic fracture zones. The shear zones and the reactivated fracture zones form a conjugate system of faults, which accommodate present-day intraplate deformation in the Wharton Basin.

Ductile bookshelf faulting: A new kinematic model for Cenozoic deformation in northern Tibet

NASA Astrophysics Data System (ADS)

Zuza, A. V.; Yin, A.

2013-12-01

It has been long recognized that the most dominant features on the northern Tibetan Plateau are the >1000 km left-slip strike-slip faults (e.g., the Atyn Tagh, Kunlun, and Haiyuan faults). Early workers used the presence of these faults, especially the Kunlun and Haiyuan faults, as evidence for eastward lateral extrusion of the plateau, but their low documented offsets--100s of km or less--can not account for the 2500 km of convergence between India and Asia. Instead, these faults may result from north-south right-lateral simple shear due to the northward indentation of India, which leads to the clockwise rotation of the strike-slip faults and left-lateral slip (i.e., bookshelf faulting). With this idea, deformation is still localized on discrete fault planes, and 'microplates' or blocks rotate and/or translate with little internal deformation. As significant internal deformation occurs across northern Tibet within strike-slip-bounded domains, there is need for a coherent model to describe all of the deformational features. We also note the following: (1) geologic offsets and Quaternary slip rates of both the Kunlun and Haiyuan faults vary along strike and appear to diminish to the east, (2) the faults appear to kinematically link with thrust belts (e.g., Qilian Shan, Liupan Shan, Longmen Shan, and Qimen Tagh) and extensional zones (e.g., Shanxi, Yinchuan, and Qinling grabens), and (3) temporal relationships between the major deformation zones and the strike-slip faults (e.g., simultaneous enhanced deformation and offset in the Qilian Shan and Liupan Shan, and the Haiyuan fault, at 8 Ma). We propose a new kinematic model to describe the active deformation in northern Tibet: a ductile-bookshelf-faulting model. With this model, right-lateral simple shear leads to clockwise vertical axis rotation of the Qaidam and Qilian blocks, and left-slip faulting. This motion creates regions of compression and extension, dependent on the local boundary conditions (e.g., rigid Tarim vs. eastern China moving eastward relative to Eurasia), which results in the development of thrust and extensional belts. These zones heterogeneously deform the wall-rock of the major strike-slip faults, causing the faults to stretch (an idea described by W.D. Means 1989 GEOLOGY). This effect is further enhanced by differential fault rotation, leading to more slip in the west, where the effect of India's indentation is more pronounced, than in the east. To investigate the feasibility of this model, we have examined geologic offsets, Quaternary fault slip rates, and GPS velocities, both from existing literature and our own observations. We compare offsets with the estimated shortening and extensional strain in the wall-rocks of the strike-slip faults. For example, if this model is valid, the slip on the eastern segment of the Haiyuan fault (i.e., ~25 km) should be compatible with shortening in the Liupan Shan and extension in the Yinchuan graben. We also present simple analogue model experiments to document the strain accumulated in bookshelf fault systems under different initial and boundary conditions (e.g., rigid vs. free vs. moving boundaries, heterogeneous or homogenous materials, variable strain rates). Comparing these experimentally derived strain distributions with those observed within the plateau can help elucidate which factors dominantly control regional deformation.

Activation of Actuating Hydrogels with WS2 Nanosheets for Biomimetic Cellular Structures and Steerable Prompt Deformation.

PubMed

Zong, Lu; Li, Xiankai; Han, Xiangsheng; Lv, Lili; Li, Mingjie; You, Jun; Wu, Xiaochen; Li, Chaoxu

2017-09-20

Macroscopic soft actuation is intrinsic to living organisms in nature, including slow deformation (e.g., contraction, bending, twisting, and curling) of plants motivated by microscopic swelling and shrinking of cells, and rapid motion of animals (e.g., deformation of jellyfish) motivated by cooperative nanoscale movement of motor proteins. These actuation behaviors, with an exceptional combination of tunable speed and programmable deformation direction, inspire us to design artificial soft actuators for broad applications in artificial muscles, nanofabrication, chemical valves, microlenses, soft robotics, etc. However, so far artificial soft actuators have been typically produced on the basis of poly(N-isopropylacrylamide) (PNiPAM), whose deformation is motived by volumetric shrinkage and swelling in analogue to plant cells, and exhibits sluggish actuation kinetics. In this study, alginate-exfoliated WS 2 nanosheets were incorporated into ice-template-polymerized PNiPAM hydrogels with the cellular microstructures which mimic plant cells, yet the prompt steerable actuation of animals. Because of the nanosheet-reinforced pore walls formed in situ in freezing polymerization and reasonable hierarchical water channels, this cellular hybrid hydrogel achieves super deformation speed (on the order of magnitude of 10° s), controllable deformation direction, and high near-infrared light responsiveness, offering an unprecedented platform of artificial muscles for various soft robotics and devices (e.g., rotator, microvalve, aquatic swimmer, and water-lifting filter).

A Cerenkov-delta E-Cerenkov detector for high energy cosmic ray isotopes and an accelerator study of Ar-40 and Fe-56 fragmentation. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Lau, K. H.

1985-01-01

A high energy cosmic ray detector--the High Energy Isotope Spectrometer Telescope (HEIST) is described. It is a large area (0.25 m(swp 2) SR) balloon borne isotope spectrometer designed to make high resolution measurements of isotopes in the element range from neon to nickel (10 Z 28) at energies of about 2 GeV/nucleon. HEIST determines the mass of individual nuclei by measuring both the change in the Lorentz factor (delta gamma) that results from traversing the NaI stack, and the energy loss (delta E) in the stack. Since the total energy of an isotope is given by E = (gamma M), the mass M can be determined by M = delta E/delta, gamma. The instrument is designed to achieve a typical mass resolution of 0.2 amu. The isotopic composition of the fragments from the breakup of high energy An-40 and Fe-56 nuclei are measured experimentally. Isotope yields are compared with calculated yields based on semi-empirical cross-section formulae.

Axially deformed solution of the Skyrme-Hartree-Fock-Bogolyubov equations using the transformed harmonic oscillator basis (III) HFBTHO (v3.00): A new version of the program

NASA Astrophysics Data System (ADS)

Perez, R. Navarro; Schunck, N.; Lasseri, R.-D.; Zhang, C.; Sarich, J.

2017-11-01

We describe the new version 3.00 of the code HFBTHO that solves the nuclear Hartree-Fock (HF) or Hartree-Fock-Bogolyubov (HFB) problem by using the cylindrical transformed deformed harmonic oscillator basis. In the new version, we have implemented the following features: (i) the full Gogny force in both particle-hole and particle-particle channels, (ii) the calculation of the nuclear collective inertia at the perturbative cranking approximation, (iii) the calculation of fission fragment charge, mass and deformations based on the determination of the neck, (iv) the regularization of zero-range pairing forces, (v) the calculation of localization functions, (vi) a MPI interface for large-scale mass table calculations. Program Files doi:http://dx.doi.org/10.17632/c5g2f92by3.1 Licensing provisions: GPL v3 Programming language: FORTRAN-95 Journal reference of previous version: M.V. Stoitsov, N. Schunck, M. Kortelainen, N. Michel, H. Nam, E. Olsen, J. Sarich, and S. Wild, Comput. Phys. Commun. 184 (2013). Does the new version supersede the previous one: Yes Summary of revisions: 1. the Gogny force in both particle-hole and particle-particle channels was implemented; 2. the nuclear collective inertia at the perturbative cranking approximation was implemented; 3. fission fragment charge, mass and deformations were implemented based on the determination of the position of the neck between nascent fragments; 4. the regularization method of zero-range pairing forces was implemented; 5. the localization functions of the HFB solution were implemented; 6. a MPI interface for large-scale mass table calculations was implemented. Nature of problem:HFBTHO is a physics computer code that is used to model the structure of the nucleus. It is an implementation of the energy density functional (EDF) approach to atomic nuclei, where the energy of the nucleus is obtained by integration over space of some phenomenological energy density, which is itself a functional of the neutron and proton intrinsic densities. In the present version of HFBTHO, the energy density derives either from the zero-range Skyrme or the finite-range Gogny effective two-body interaction between nucleons. Nuclear super-fluidity is treated at the Hartree-Fock-Bogolyubov (HFB) approximation. Constraints on the nuclear shape allows probing the potential energy surface of the nucleus as needed e.g., for the description of shape isomers or fission. The implementation of a local scale transformation of the single-particle basis in which the HFB solutions are expanded provide a tool to properly compute the structure of weakly-bound nuclei. Solution method: The program uses the axial Transformed Harmonic Oscillator (THO) single-particle basis to expand quasiparticle wave functions. It iteratively diagonalizes the Hartree-Fock-Bogolyubov Hamiltonian based on generalized Skyrme-like energy densities and zero-range pairing interactions or the finite-range Gogny force until a self-consistent solution is found. A previous version of the program was presented in M.V. Stoitsov, N. Schunck, M. Kortelainen, N. Michel, H. Nam, E. Olsen, J. Sarich, and S. Wild, Comput. Phys. Commun. 184 (2013) 1592-1604 with much of the formalism presented in the original paper M.V. Stoitsov, J. Dobaczewski, W. Nazarewicz, P. Ring, Comput. Phys. Commun. 167 (2005) 43-63. Additional comments: The user must have access to (i) the LAPACK subroutines DSYEEVR, DSYEVD, DSYTRF and DSYTRI, and their dependencies, which compute eigenvalues and eigenfunctions of real symmetric matrices, (ii) the LAPACK subroutines DGETRI and DGETRF, which invert arbitrary real matrices, and (iii) the BLAS routines DCOPY, DSCAL, DGEMM and DGEMV for double-precision linear algebra (or provide another set of subroutines that can perform such tasks). The BLAS and LAPACK subroutines can be obtained from the Netlib Repository at the University of Tennessee, Knoxville: http://netlib2.cs.utk.edu/.

Analysis of isomeric ratios for medium-mass nuclei

DOE Office of Scientific and Technical Information (OSTI.GOV)

Danagulyan, A. S.; Hovhannisyan, G. H., E-mail: hov-gohar@ysu.am; Bakhshiyan, T. M.

Values of the isomeric ratios for product nuclei originating from simple charge-exchange reactions were analyzed. The cross sections for the formation of product nuclei in ground and isomeric states were calculated with the aid of the TALYS 1.4 and EMPIRE 3.2 codes. The calculated values of the isomeric ratios were compared with their experimental counterparts taken from the EXFOR database. For the {sup 86,87}Y, {sup 94,95,96,99}Tc, and {sup 44}Sc nuclei, the experimental values of the isomeric ratios exceed the respective calculated values. The nuclei in question feature weak deformations and have high-spin yrast lines and rotational bands. The possible reasonmore » behind the discrepancy between theoretical and experimental isomeric ratios is that the decay of yrast states leads with a high probability to the formation of isomeric states of detected product nuclei.« less

New method of limb deformities correction in children.

PubMed Central

Atar, D.; Lehman, W. B.; Grant, A. D.; Strongwater, A.; Frankel, V. H.; Posner, M.; Golyakhovsky, V.

1992-01-01

A new "bloodless" technique (Ilizarov) was used to correct 36 limb deformities in 29 children. There were six leg length discrepancies, five achondroplasias, four deformed feet, five joint contractures, one rotational deformity of tibia, and in three the apparatus was used as an external fixator after corrective osteotomy. Lengthening was accomplished in 15 of the 16 procedures (93%). Average increase in femur length was 10 cm (32%), in tibial length 7.5 cm (30%), in humerus 11 cm (40%). Bony union was achieved in two out of five pseudoarthroses. Four deformed feet were fully corrected. Joint contractures were corrected in four out of five. The complication rate is as high as in other methods but with the Ilizarov apparatus, longer segments of bone were lengthened and more complex deformities were treated. Complications lessened as experience was gained. Images Fig. 1a,b Fig. 1 Fig. 1c Fig. 1d Fig. 1e Fig. 2a Fig. 2b Fig. 2c Fig. 2d Fig. 2e Fig. 3a Fig. 3b Fig. 3c Fig. 3d Fig. 4a Fig. 4b Fig. 4c Fig. 4d Fig. 4e Fig. 5a Fig. 5b Fig. 5c Fig. 5d PMID:1490205

The 3D model: explaining densification and deformation mechanisms by using 3D parameter plots.

PubMed

Picker, Katharina M

2004-04-01

The aim of the study was to analyze very differently deforming materials using 3D parameter plots and consequently to gain deeper insights into the densification and deformation process described with the 3D model in order to define an ideal tableting excipient. The excipients used were dicalcium phosphate dihydrate (DCPD), sodium chloride (NaCl), microcrystalline cellulose (MCC), xylitol, mannitol, alpha-lactose monohydrate, maltose, hydroxypropyl methylcellulose (HPMC), sodium carboxymethylcellulose (NaCMC), cellulose acetate (CAC), maize starch, potato starch, pregelatinized starch, and maltodextrine. All of the materials were tableted to graded maximum relative densities (rhorel, max) using an eccentric tableting machine. The data which resulted, namely force, displacement, and time, were analyzed by the application of 3D modeling. Different particle size fractions of DCPD, CAC, and MCC were analyzed in addition. Brittle deforming materials such as DCPD exhibited a completely different 3D parameter plot, with low time plasticity, d, and low pressure plasticity, e, and a strong decrease in omega values when densification increased, in contrast to the plastically deforming MCC, which had much higher d, e, and omega values. e and omega values changed only slightly when densification increased for MCC. NaCl showed less of a decrease in omega values than DCPD did, and the d and e values were between those of MCC and DCPD. The sugar alcohols, xylitol and mannitol, behaved in a similar fashion to sodium chloride. This is also valid for the crystalline sugars, alpha-lactose monohydrate, and maltose. However, the sugars are more brittle than the sugar alcohols. The cellulose derivatives, HPMC, NaCMC, and CAC, are as plastic as MCC, however, their elasticity depends on substitution indicated by lower (more elastic) or higher (less elastic) omega values. The native starches, maize starch and potato starch, are very elastic, and pregelatinized starch and maltodextrine are less elastic and exhibited higher omega values. Deformation behavior as shown in 3D parameter plots depends on particle size for polymers such as CAC and MCC; however, it does not depend on particle size for brittle materials such as DCPD. An ideally deforming tableting excipient should exhibit high e, d, and omega values with a constant ratio of e and omega at increasing densification.

Dynamic shape transitions in the sdg boson model

NASA Astrophysics Data System (ADS)

Kuyucak, S.

The dynamic evolution of shapes in the sdg interacting boson model is investigated using the angular momentum projected mean field theory. Deformed nuclei are found to be quite stable against shape changes but transitional nuclei could exhibit dynamic shape transitions in the region L = 10-20. Conditions of existence and experimental signatures for dynamic shape transitions are discussed together with a likely candidate, 192Os.

Figure Caption for pair of images of 'Comet Nucleus Q

NASA Technical Reports Server (NTRS)

2002-01-01

Figure Caption for pair of images of 'Comet Nucleus Q'. 21Jul94 Last Look at the Q-nuclei First image - March 30, 1994. Two Q-nuclei and a split nucleus, P. Second image - July 20, 1994. at T - 10 hours. Both nuclei still show no sign of further fragmentation, although the coma near each is being stretched out along the direction of motion. Both images were taken with the WFPC2 Planetary Camera using a red filter. Credit: H. A. Weaver and T. E. Smith

The orientation distribution of tunneling-related quantities

NASA Astrophysics Data System (ADS)

Seif, W. M.; Refaie, A. I.; Botros, M. M.

2018-03-01

In the nuclear tunneling processes involving deformed nuclei, most of the tunneling-related quantities depend on the relative orientations of the participating nuclei. In the presence of different multipole deformations, we study the variation of a few relevant quantities for the α-decay and the sub-barrier fusion processes, in an orientation degree of freedom. The knocking frequency and the penetration probability are evaluated within the Wentzel-Kramers-Brillouin approximation. The interaction potential is calculated with Skyrme-type nucleon-nucleon interaction. We found that the width of the potential pocket, the Coulomb barrier radius, the penetration probability, the α-decay width, and the fusion cross-section follow consistently the orientation-angle variation of the radius of the deformed nucleus. The orientation distribution patterns of the pocket width, the barrier radius, the logarithms of the penetrability, the decay width, and the fusion cross-section are found to be highly analogous to pattern of the deformed-nucleus radius. The curve patterns of the orientation angle distributions of the internal pocket depth, the Coulomb barrier height and width, as well as the knocking frequency simulate inversely the variation of the deformed nucleus radius. The predicted orientation behaviors will be of a special interest in predicting the optimum orientations for the tunneling processes.

Effective field theory for triaxially deformed nuclei

NASA Astrophysics Data System (ADS)

Chen, Q. B.; Kaiser, N.; Meißner, Ulf-G.; Meng, J.

2017-10-01

Effective field theory is generalized to investigate the rotational motion of triaxially deformed even-even nuclei. The Hamiltonian for the triaxial rotor is obtained up to next-to-leading order within the effective field theory formalism. Its applicability is examined by comparing with a five-dimensional rotor-vibrator Hamiltonian for the description of the energy spectra of the ground state and γ band in Ru isotopes. It is found that by taking into account the next-to-leading order corrections, the ground state band in the whole spin region and the γ band in the low spin region are well described. The deviations for high-spin states in the γ bands point towards the importance of including vibrational degrees of freedom in the effective field theory formulation.

Systematics of signature inversion in odd-odd nuclei in the mass regions A=80 and A=160

NASA Astrophysics Data System (ADS)

Zheng, Renrong; Zhu, Shunquan; Cheng, Nanpu; Wen, Jiayan

2001-07-01

Based on an axially symmetric rotor plus quasiparticles model, the study of the signature inversion (SI) in odd-odd nuclei in the mass region A=160 is extended to include the region A=80. In spite of many differences between the two mass regions, the calculation results show that the possible SI mechanism, which has been confirmed by the calculation of odd-odd nuclei in the A=160 region (i.e., the competition between the n-p interaction and the Coriolis force in low-K space) is also appropriate for odd-odd nuclei in the A=80 region. This seems to indicate that there may be a universal mechanism of SI in odd-odd nuclei for different mass regions.

High-density amorphous ice: nucleation of nanosized low-density amorphous ice

NASA Astrophysics Data System (ADS)

Tonauer, Christina M.; Seidl-Nigsch, Markus; Loerting, Thomas

2018-01-01

The pressure dependence of the crystallization temperature of different forms of expanded high-density amorphous ice (eHDA) was scrutinized. Crystallization at pressures 0.05-0.30 GPa was followed using volumetry and powder x-ray diffraction. eHDA samples were prepared via isothermal decompression of very high-density amorphous ice at 140 K to different end pressures between 0.07-0.30 GPa (eHDA0.07-0.3). At 0.05-0.17 GPa the crystallization line T x (p) of all eHDA variants is the same. At pressures  >0.17 GPa, all eHDA samples decompressed to pressures  <0.20 GPa exhibit significantly lower T x values than eHDA0.2 and eHDA0.3. We rationalize our findings with the presence of nanoscaled low-density amorphous ice (LDA) seeds that nucleate in eHDA when it is decompressed to pressures  <0.20 GPa at 140 K. Below ~0.17 GPa, these nanosized LDA domains are latent within the HDA matrix, exhibiting no effect on T x of eHDA<0.2. Upon heating at pressures  ⩾0.17 GPa, these nanosized LDA nuclei transform to ice IX nuclei. They are favored sites for crystallization and, hence, lower T x . By comparing crystallization experiments of bulk LDA with the ones involving nanosized LDA we are able to estimate the Laplace pressure and radius of ~0.3-0.8 nm for the nanodomains of LDA. The nucleation of LDA in eHDA revealed here is evidence for the first-order-like nature of the HDA  →  LDA transition, supporting water’s liquid-liquid transition scenarios.

Precortical phase of Alzheimer’s disease (AD)-related tau cytoskeletal pathology

PubMed Central

Stratmann, Katharina; Heinsen, Helmut; Korf, Horst-Werner; Del Turco, Domenico; Ghebremedhin, Estifanos; Seidel, Kay; Bouzrou, Mohamed; Grinberg, Lea T.; Bohl, Jürgen; Wharton, Stephen B; den Dunnen, Wilfred; Rüb, Udo

2015-01-01

Alzheimer’s disease (AD) represents the most frequent progressive neuropsychiatric disorder worldwide leading to dementia and accounts for 60 to 70% of demented individuals. In view of the early appearance of neuronal deposits of the hyperphosphorylated cytoskeletal protein tau in the transentorhinal and entorhinal regions of the allocortex (i.e. in Braak and Braak AD stage I in the evolution of the AD-related cortical tau cytoskeletal pathology) it has been believed for a long time that these allocortical regions represent the first brain targets of the AD-related tau cytoskeletal pathology. However, recent pathoanatomical studies suggested that the subcortical brain nuclei that send efferent projections to the transentorhinal and entorhinal regions may also comprise AD-related cytoskeletal changes already at very early Braak and Braak AD stages. In order to corroborate these initial results we systematically investigated the presence and extent of the AD-related cytoskeletal pathology in serial thick tissue sections through all the subcortical nuclei known to send efferent projections to these vulnerable allocortical regions of three individuals with Braak and Braak AD stage 0 and fourteen individuals with Braak and Braak AD stage I by means of immunostainings with the anti-tau antibody AT8. These investigations revealed consistent AT8 immunoreactive neuronal tau cytoskeletal pathology in a subset of these subcortical nuclei (i.e. medial septal nucleus, nuclei of the vertical and horizontal limbs of the diagonal band of Broca, basal nucleus of Meynert; claustrum; hypothalamic ventromedial, tuberomamillary and supramamillary nuclei, perifornical region and lateral area; thalamic central medial, laterodorsal, subparafascicular, and central lateral nuclei, medial pulvinar and limitans-suprageniculate complex; peripeduncular nucleus, dopaminergic substantia nigra and ventral tegmental area, periaqueductal gray, midbrain and pontine dorsal raphe nuclei, locus coeruleus, and parabrachial nuclei) in the Braak and Braak AD stage 0 individuals and in all of these subcortical nuclei in the Braak and Braak AD stage I individuals. The widespread affection of the subcortical nuclei in our Braak and Braak AD stage I individuals shows that the extent of the subcortical tau cytoskeletal pathology in this AD stage has been considerably underestimated during the last decades. In addition, our novel findings in the Braak and Braak AD stage 0 individuals support the concept that subcortical nuclei become already affected during an early ‘pre-cortical’ evolutional phase before the first AD-related cytoskeletal changes occur in the well-known cortical predilection sites of the mediobasal temporal lobe (i.e. transentorhinal and entorhinal regions). In addition, our new findings indicate that the AD-related tau cytoskeletal pathology by no means is confined to single subcortical nuclei of Braak and Braak AD stage 0 individuals, but may develop in a large variety of their subcortical nuclei interconnected with the allocortical entorhinal and transentorhinal regions. Accordingly, these very early involved subcortical brain regions may represent the origin of the AD-related tau cytoskeletal pathology, from where the neuronal cytoskeletal pathology takes an ascending course towards the secondarily affected allocortex and spreads transneuronally along anatomical pathways and interconnectivities in predictable and stereotypical sequences PMID:26193084

Deformation dependence of proton decay rates and angular distributions in a time-dependent approach

NASA Astrophysics Data System (ADS)

Carjan, N.; Talou, P.; Strottman, D.

1998-12-01

A new, time-dependent, approach to proton decay from axially symmetric deformed nuclei is presented. The two-dimensional time-dependent Schrödinger equation for the interaction between the emitted proton and the rest of the nucleus is solved numerically for well defined initial quasi-stationary proton states. Applied to the hypothetical proton emission from excited states in deformed nuclei of 208Pb, this approach shows that the problem cannot be reduced to one dimension. There are in general more than one directions of emission with wide distributions around them, determined mainly by the quantum numbers of the initial wave function rather than by the potential landscape. The distribution of the "residual" angular momentum and its variation in time play a major role in the determination of the decay rate. In a couple of cases, no exponential decay was found during the calculated time evolution (2×10-21 sec) although more than half of the wave function escaped during that time.

A microscopic explanation of the isotonic multiplet at N=90

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gupta, J. B., E-mail: jbgupta2011@gmail.com

2014-08-14

The shape phase transition from spherical to soft deformed at N=88-90 was observed long ago. After the prediction of the X(5) symmetry, for which analytical solution of the nuclear Hamiltonian is given [1], good examples of X(5) nuclei were identified in the N=90 isotones of Nd, Sm, Gd and Dy, in the recent works. The N=90 isotones have almost the similar deformed level structure, forming the isotonic multiplet in Z=50-66, N=82-104 quadrant. This is explained microscopically in terms of the Nilsson level diagram. Using the Dynamic Pairing-Plus-Quadrupole model of Kumar-Baranger, the quadrupole deformation and the occupancies of the neutrons andmore » protons in these nuclei have been calculated, which support the formation of N=88, 90 isotonic multiplets. The existence of F-spin multiplets in Z=66-82, N=82-104 quadrant, identified in earlier works on the Interacting Boson Model, is also explained in our study.« less

Recent advances in analysis and prediction of Rock Falls, Rock Slides, and Rock Avalanches using 3D point clouds

NASA Astrophysics Data System (ADS)

Abellan, A.; Carrea, D.; Jaboyedoff, M.; Riquelme, A.; Tomas, R.; Royan, M. J.; Vilaplana, J. M.; Gauvin, N.

2014-12-01

The acquisition of dense terrain information using well-established 3D techniques (e.g. LiDAR, photogrammetry) and the use of new mobile platforms (e.g. Unmanned Aerial Vehicles) together with the increasingly efficient post-processing workflows for image treatment (e.g. Structure From Motion) are opening up new possibilities for analysing, modeling and predicting rock slope failures. Examples of applications at different scales ranging from the monitoring of small changes at unprecedented level of detail (e.g. sub millimeter-scale deformation under lab-scale conditions) to the detection of slope deformation at regional scale. In this communication we will show the main accomplishments of the Swiss National Foundation project "Characterizing and analysing 3D temporal slope evolution" carried out at Risk Analysis group (Univ. of Lausanne) in close collaboration with the RISKNAT and INTERES groups (Univ. of Barcelona and Univ. of Alicante, respectively). We have recently developed a series of innovative approaches for rock slope analysis using 3D point clouds, some examples include: the development of semi-automatic methodologies for the identification and extraction of rock-slope features such as discontinuities, type of material, rockfalls occurrence and deformation. Moreover, we have been improving our knowledge in progressive rupture characterization thanks to several algorithms, some examples include the computing of 3D deformation, the use of filtering techniques on permanently based TLS, the use of rock slope failure analogies at different scales (laboratory simulations, monitoring at glacier's front, etc.), the modelling of the influence of external forces such as precipitation on the acceleration of the deformation rate, etc. We have also been interested on the analysis of rock slope deformation prior to the occurrence of fragmental rockfalls and the interaction of this deformation with the spatial location of future events. In spite of these recent advances, a great challenge still remains in the development of new algorithms for more accurate techniques for 3D point cloud treatment (e.g. filtering, segmentation, etc.) aiming to improve rock slope characterization and monitoring, a series of exciting research findings are expected in the forthcoming years.

The Interaction of Statistics and Geology -- Finite Deformations.

DTIC Science & Technology

1980-11-01

UNCLASSIFIlED TR-178-SER-2 N 7 DIZO9 f l l ff-63f ~ l f f PRNEO VN TO TTSISF61/ EOM.’..lN 11 1 .1 2I " IIIj.5IIHL4. 1. 111 1----_III MICROCOPY RESOLUTION TEST ... Ramsey (1967). These might be the result of a sequence of linear deformations or homogeneous strains. In this section we summarize the description of...problem may be found in textbooks (see e.g. Theil (1971)) on Econometrics : y=B&+f, x=&+e where the errors of measurement e and f of x and y are

Evaluating the relationship between lateral slip and repeated fold deformation along a transtensive step-over on the San Andreas fault at the Frazier Mountain site

NASA Astrophysics Data System (ADS)

Weldon, R. J.; Streig, A. R.; Frazier Mountain SoSAFE Trenching Team

2011-12-01

Transtensive step-overs known as sags are among the most ubiquitous features of strike slip faults. These structures create closed depressions that collect sediment, are often wet and thus preserve organic material that can be used to date the thick and rapidly accumulating section. It is clear from historical ruptures that these depressions grow incrementally with each earthquake. We are developing methods to carefully document and separate individual folding events, and to relate the amount of sagging or folding to the amount of horizontal slip creating the sag, with the goal of generating slip per event chronologies. This will be useful as sags are often the best sites for preserving evidence of earthquake timing, and determining slip at these sites will eliminate the ambiguity inherent in tying earthquake age data from micro-stratigraphic sites to nearby undated sites with good micro-geomorphic slip evidence. We apply this approach to the Frazier Mountain site on the Southern San Andreas fault where we integrate trenching, cone penetrometer testing (CPT), surveying, photomosaicing, B4 LiDAR data and GIS techniques to make a detailed 3D map of subsurface geology, fault traces and related folds across the site. These data are used to generate structure contour and isopach maps for key stratigraphic units in order to evaluate fold deformation of paleo-ground surfaces across a transtensional step-over on the San Andreas fault. Approximately 20 trenches show the main active trace of the San Andreas fault right stepping ~30 m over ~100 m along strike producing two small synclinal sags that dramatically thicken the stratigraphic section. The northwest sag is about 50 m long, 5 m wide, and the southwest sag measures 20 m long and about 8 m wide. The Frazier Mountain site has yielded good earthquake chronologies, and relationships between fold deformation and surface fault rupture for the last 6 earthquakes. We observe that the degree of sagging in the synclines varies along strike for each feature, but that the ratio of fold deformation between earthquake horizons remains constant in both synclines. The penultimate earthquake, E2, produced a depression that was infilled by gravel which was subsequently folded in the most recent earthquake in 1857. Fine-grained alluvial units overlie the gravel and fill the 1857 depression such that the current surface is relatively horizontal. E2 has double the observed folding associated with the 1857 event in the core of the NW syncline. Earthquake E6 has double the amount of fold deformation observed across the E3 paleo-surface in both sags, and three times the deformation observed on the E2 surface in the NW sag. Ratios of fold deformation between events are E2 = 2*E1, E6 = 3*E2, and E6 = 2*E3. We plan to model the folding to quantitatively assess the lateral offset, but to date we have only been able to establish minimum offset values (Scharer, Gibson, Weldon, Streig, this meeting). Qualitatively, the realitive amounts of folding suggest all slip events are similar to 1857, which had ~5 meters slip at this site.

Initial Eccentricity in Deformed 197Au+197Au and 238U+238U Collisions at RHIC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Filip, Peter; Lednicky, Richard; Masui, Hiroshi

2010-07-07

Initial eccentricity and eccentricity fluctuations of the interaction volume created in relativistic collisions of deformed {sup 197}Au and {sup 238}U nuclei are studied using optical and Monte-Carlo (MC) Glauber simulations. It is found that the non-sphericity noticeably influences the average eccentricity in central collisions and eccentricity fluctuations are enhanced due to deformation. Quantitative results are obtained for Au+Au and U+U collisions at energy {radical}s{sub NN} = 200 GeV.

Shape coexistence in 140Sm and the onset of deformation below N=82 from lifetime measurements

NASA Astrophysics Data System (ADS)

Cardona, M. A.; Lunardi, S.; Bazzacco, D.; de Angelis, G.; Roca, V.

1991-08-01

Different deformations for the two bands built above the (πh11/2)2 10+ and the (νh11/2)-2 10+ states in 140Sm have been determined from lifetime measurements using the reaction 106Pd(37Cl,p2n)140Sm at 143 MeV. The β values derived for the N=78 and N=80 core nuclei, coexisting in 140Sm, complete the systematics of nuclear deformation from N=72 to 80.

On the elastic–plastic decomposition of crystal deformation at the atomic scale

DOE PAGES

Stukowski, Alexander; Arsenlis, A.

2012-03-02

Given two snapshots of an atomistic system, taken at different stages of the deformation process, one can compute the incremental deformation gradient field, F, as defined by continuum mechanics theory, from the displacements of atoms. However, such a kinematic analysis of the total deformation does not reveal the respective contributions of elastic and plastic deformation. We develop a practical technique to perform the multiplicative decomposition of the deformation field, F = F eF p, into elastic and plastic parts for the case of crystalline materials. The described computational analysis method can be used to quantify plastic deformation in a materialmore » due to crystal slip-based mechanisms in molecular dynamics and molecular statics simulations. The knowledge of the plastic deformation field, F p, and its variation with time can provide insight into the number, motion and localization of relevant crystal defects such as dislocations. As a result, the computed elastic field, F e, provides information about inhomogeneous lattice strains and lattice rotations induced by the presence of defects.« less

Analysis of Quasi-Elastic e-n and e-p Scattering from Deuterium

NASA Astrophysics Data System (ADS)

Balsamo, Alexander; Gilfoyle, Gerard; CLAS12 Collaboration

2017-09-01

One of Jefferson Lab's goals is to unravel the quark-gluon structure of nuclei. We will use the ratio, R, of electron-neutron to electron-proton scattering on deuterium to probe the magnetic form factor of the neutron. We have developed an end-to-end analysis from simulation to extraction of R in quasi-elastic kinematics for an approved experiment with the CLAS12 detector. We focus on neutrons detected in the CLAS12 calorimeters and protons measured with the CLAS12 forward detector. Events were generated with the Quasi-Elastic Event Generator (QUEEG) and passed through the Monte Carlo code gemc to simulate the CLAS12 response. These simulated events were reconstructed using the latest CLAS12 Common Tools. We first match the solid angle for e-n and e-p events. The electron information is used to predict the path of both a neutron and proton through CLAS12. If both particles interact in CLAS12 the e-n and e-p events have the same solid angle. We select QE events by searching for nuclei near the predicted position. An angular cut between the predicted 3-momentum of the nucleon and the measured value, θpq, separates QE and inelastic events. We will show the simulated R as a function of the four-momentum transfer Q2. Work supported by the University of Richmond and the US Department of Energy.

Proflavine sensitivity of RNA processing in isolated nuclei.

PubMed Central

Yannarell, A; Niemann, M; Schumm, D E; Webb, T E

1977-01-01

The intercalating agent proflavine inhibits the processing and subsequent release of preformed messenger RNA and ribosomal RNA from isolated liver nuclei to surrogate cytoplasm. The direct effect of proflavine on these processes, as monitored in a reconstituted cell-free system, supports the theory that base-paired segments (i.e. hairpin loops) in the precursor RNA's are involved as recognition sites in nuclear RNA processing. PMID:866181

The magnification of structural anomalies with Grodzins systematic in the framework of Asymmetric Rotor Model

NASA Astrophysics Data System (ADS)

Bindra, Amit; Mittal, H. M.

2018-07-01

The dependence of Grodzins systematic as shape fluctuation energy product ESF * B (E 2) ↑ and rotational energy product EROT * B (E 2) ↑ on the Asymmetry parameter γ0 is carried out in the Z = 50-82, N = 82-126 major shell space. The Asymmetry parameter γ0, varying from 0° to 60°, reflects the change in nuclear structure from prolate to oblate. Strong anomalies are highlighted in the shape transitional isotopes. The product ESF * B (E 2) ↑ evolves from low negative values for vibrator nuclei, passing close to zero and then substantially increasing towards triaxial rotor limit with γ0 ∼ 30 °. However, the product EROT * B (E 2) ↑ decreases as a function of γ0 for all the nuclei approaching towards triaxiality from Z = 50-82, N = 82-126. Anomalies are also noticed for the N > 104 region where the product EROT * B (E 2) ↑ decreases in zigzag phase for 188-196Pt isotopes corresponding to γ0 ∼ 25- 30 ° and this reflects the breakdown of coherence between rotational energy EROT and excitation strength B (E 2) ↑. The product EROT * B (E 2) ↑ indicates the shape phase transition for Pt isotopic chain from spherical to γ - soft to slightly triaxial. We have studied for the first time the role of Grodzins systematic ESF and EROT in the framework of Asymmetric Rotor Model.

3D Tensorial Elastodynamics for Isotropic Media on Vertically Deformed Meshes

NASA Astrophysics Data System (ADS)

Shragge, J. C.

2017-12-01

Solutions of the 3D elastodynamic wave equation are sometimes required in industrial and academic applications of elastic reverse-time migration (E-RTM) and full waveform inversion (E-FWI) that involve vertically deformed meshes. Examples include incorporating irregular free-surface topography and handling internal boundaries (e.g., water bottom) directly into the computational meshes. In 3D E-RTM and E-FWI applications, the number of forward modeling simulations can number in the tens of thousands (per iteration), which necessitates the development of stable, accurate and efficient 3D elastodynamics solvers. For topographic scenarios, most finite-difference solution approaches use a change-of-variable strategy that has a number of associated computational challenges, including difficulties in handling of the free-surface boundary condition. In this study, I follow a tensorial approach and use a generalized family of analytic transforms to develop a set of analytic equations for 3D elastodynamics that directly incorporates vertical grid deformations. Importantly, this analytic approach allows for the specification of an analytic free-surface boundary condition appropriate for vertically deformed meshes. These equations are both straightforward and efficient to solve using a velocity-stress formulation with finite-difference (MFD) operators implemented on a fully staggered grid. Moreover, I demonstrate that the use of mimetic finite difference (MFD) methods allows stable, accurate, and efficient numerical solutions to be simulated for typical topographic scenarios. Examples demonstrate that high-quality elastic wavefields can be generated for topographic surfaces exhibiting significant topographic relief.

Multifaceted Quadruplet of Low-Lying Spin-Zero States in 66Ni: Emergence of Shape Isomerism in Light Nuclei

NASA Astrophysics Data System (ADS)

Leoni, S.; Fornal, B.; Mǎrginean, N.; Sferrazza, M.; Tsunoda, Y.; Otsuka, T.; Bocchi, G.; Crespi, F. C. L.; Bracco, A.; Aydin, S.; Boromiza, M.; Bucurescu, D.; Cieplicka-Oryǹczak, N.; Costache, C.; Cǎlinescu, S.; Florea, N.; GhiÅ£ǎ, D. G.; Glodariu, T.; Ionescu, A.; Iskra, Ł. W.; Krzysiek, M.; Mǎrginean, R.; Mihai, C.; Mihai, R. E.; Mitu, A.; NegreÅ£, A.; NiÅ£ǎ, C. R.; Olǎcel, A.; Oprea, A.; Pascu, S.; Petkov, P.; Petrone, C.; Porzio, G.; Şerban, A.; Sotty, C.; Stan, L.; Ştiru, I.; Stroe, L.; Şuvǎilǎ, R.; Toma, S.; Turturicǎ, A.; Ujeniuc, S.; Ur, C. A.

2017-04-01

A search for shape isomers in the 66Ni nucleus was performed, following old suggestions of various mean-field models and recent ones, based on state-of-the-art Monte Carlo shell model (MCSM), all considering 66Ni as the lightest nuclear system with shape isomerism. By employing the two-neutron transfer reaction induced by an 18O beam on a 64Ni target, at the sub-Coulomb barrier energy of 39 MeV, all three lowest-excited 0+ states in 66Ni were populated and their γ decay was observed by γ -coincidence technique. The 0+ states lifetimes were assessed with the plunger method, yielding for the 02+, 03+, and 04+ decay to the 21+ state the B (E 2 ) values of 4.3, 0.1, and 0.2 Weisskopf units (W.u.), respectively. MCSM calculations correctly predict the existence of all three excited 0+ states, pointing to the oblate, spherical, and prolate nature of the consecutive excitations. In addition, they account for the hindrance of the E 2 decay from the prolate 04+ to the spherical 21+ state, although overestimating its value. This result makes 66Ni a unique nuclear system, apart from U,238236 , in which a retarded γ transition from a 0+ deformed state to a spherical configuration is observed, resembling a shape-isomerlike behavior.

The Brainstem Tau Cytoskeletal Pathology of Alzheimer's Disease: A Brief Historical Overview and Description of its Anatomical Distribution Pattern, Evolutional Features, Pathogenetic and Clinical Relevance.

PubMed

Rüb, Udo; Stratmann, Katharina; Heinsen, Helmut; Turco, Domenico Del; Seidel, Kay; Dunnen, Wilfred den; Korf, Horst-Werner

2016-01-01

The human brainstem is involved in the regulation of the sleep/waking cycle and normal sleep architectonics and is crucial for the performance of a variety of somatomotor, vital autonomic, oculomotor, vestibular, auditory, ingestive and somatosensory functions. It harbors the origins of the ascending dopaminergic, cholinergic, noradrenergic, serotonergic systems, as well the home base of the descending serotonergic system. In contrast to the cerebral cortex the affection of the brainstem in Alzheimer's disease (AD) by the neurofibrillary or tau cytoskeletal pathology was recognized only approximately fourty years ago in initial brainstem studies. Detailed pathoanatomical investigations of silver stained or tau immunostained brainstem tissue sections revealed nerve cell loss and prominent ADrelated cytoskeletal changes in the raphe nuclei, locus coeruleus, and in the compact parts of the substantia nigra and pedunculopontine nucleus. An additional conspicuous AD-related cytoskeletal pathology was also detected in the auditory brainstem system of AD patients (i.e. inferior colliculus, superior olive, dorsal cochlear nucleus), in the oculomotor brainstem network (i.e. rostral interstitial nucleus of the medial longitudinal fascicle, Edinger-Westphal nucleus, reticulotegmental nucleus of pons), autonomic system (i.e. central and periaqueductal grays, parabrachial nuclei, gigantocellular reticular nucleus, dorsal motor vagal and solitary nuclei, intermediate reticular zone). The alterations in these brainstem nuclei offered for the first time adequate explanations for a variety of less understood disease symptoms of AD patients: Parkinsonian extrapyramidal motor signs, depression, hallucinations, dysfunctions of the sleep/wake cycle, changes in sleeping patterns, attentional deficits, exaggerated pupil dilatation, autonomic dysfunctions, impairments of horizontal and vertical saccades, dysfunctional smooth pursuits. The very early occurrence of the AD-related cytoskeletal pathology in some of these brainstem nuclei points to a major and strategic role of the brainstem in the induction and brain spread of the AD-related cytoskeletal pathology.

New Mechanism of Low Energy Nuclear Reactions Using Superlow

NASA Astrophysics Data System (ADS)

Gareev, F. A.; Zhidkova, I. E.

2006-03-01

We proposed a new mechanism of LENR (low energy nuclear reactions) cooperative processes in the whole system - nuclei+atoms+condensed matter can occur at smaller threshold than the corresponding ones assoiciated with free constituents. The cooperative processes can be induced and enhanced by (``superlow energy'') external fields. The excess heat is the emission of internal energy, and transmutations from LENR are the result of redistribution of the internal energy of the whole system. A review of possible stimulation mechanisms of LENR is presented. We have concluded that transmutation of nuclei at low energies and excess heat are possible in the framework of the known fundamental physical laws: The universal resonance synchronization principle, and based on it, different enhancement mechanisms of reaction rates are responsible for these processes. The excitation and ionization of atoms may play the role of a trigger for LENR. F.A. Gareev, I.E. Zhidkova, E-print arXiv Nucl-th/0511092 v1 30 Nov 2005. F.A. Gareev, In: FPB-98, Novosibirsk, June 1998, p.92; F.A.Gareev, G.F. Gareeva, in: Novosibirsk, July 2000, p.161. F.A. Gareev, I.E. Zhidkova and Yu.L. Ratis, Preprint JINR P4-2004-68, Dubna, 2004. F.A. Gareev, I.E. Zhidkova, E-print arXiv Nucl-th/0505021 9 May 2005.

Research at the University of Kentucky Accelerator Laboratory

DOE PAGES

Hicks, S. F.; Kovash, M. A.

2017-10-26

The Department of Physics and Astronomy at the University of Kentucky operates a 7-MV CN Van de Graaff accelerator that produces primary beams of protons, deuterons, and helium ions. An in-terminal pulsing and bunching system operates at 1.875 MHz and is capable of providing 1 ns beam bunches at an average current of several microamperes. Nearly all ongoing research programs involve secondary pulsed neutrons produced with gas cells containing deuterium or tritium, as well as with a variety of solid targets. Most experiments are performed at a target station positioned over a deep pit, so as to reduce the backgroundmore » created by backscattered neutrons. Here, recent experiments will be described; these include: measurements of n-p scattering total cross sections from E n = 90 to 1800 keV to determine the n-p effective range parameter; the response of the plastic scintillator BC-418 below 1 MeV to low-energy recoil protons; n-p radiative capture cross sections important for our understanding of nucleosynthesis approximately 2 minutes after the occurrence of the Big Bang; γ-ray spectroscopy following inelastic neutron scattering to study nuclear structure relevant to double-β decay and to understand the role of phonon-coupled excitations in weakly deformed nuclei; and measurements of neutron elastic and inelastic scattering cross sections for nuclei that are important for energy production and for our global understanding of the interaction of neutrons with matter.« less

Research at the University of Kentucky Accelerator Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hicks, S. F.; Kovash, M. A.

The Department of Physics and Astronomy at the University of Kentucky operates a 7-MV CN Van de Graaff accelerator that produces primary beams of protons, deuterons, and helium ions. An in-terminal pulsing and bunching system operates at 1.875 MHz and is capable of providing 1 ns beam bunches at an average current of several microamperes. Nearly all ongoing research programs involve secondary pulsed neutrons produced with gas cells containing deuterium or tritium, as well as with a variety of solid targets. Most experiments are performed at a target station positioned over a deep pit, so as to reduce the backgroundmore » created by backscattered neutrons. Here, recent experiments will be described; these include: measurements of n-p scattering total cross sections from E n = 90 to 1800 keV to determine the n-p effective range parameter; the response of the plastic scintillator BC-418 below 1 MeV to low-energy recoil protons; n-p radiative capture cross sections important for our understanding of nucleosynthesis approximately 2 minutes after the occurrence of the Big Bang; γ-ray spectroscopy following inelastic neutron scattering to study nuclear structure relevant to double-β decay and to understand the role of phonon-coupled excitations in weakly deformed nuclei; and measurements of neutron elastic and inelastic scattering cross sections for nuclei that are important for energy production and for our global understanding of the interaction of neutrons with matter.« less

Review of Livermore-Led Neutron Capture Studies Using DANCE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parker, W; Sheets, S; Agvaanluvsan, U

2007-05-11

We have made neutron capture cross-section measurements using the white neutron source at the Los Alamos Science Center, the DANCE detector array (Detector for Advanced Neutron Capture Experiments) and targets important for basic science and stockpile stewardship. In this paper, we review results from (n,{gamma}) reactions on {sup 94,95}Mo, {sup 152,154,157,160,nat}Gd, {sup 151,153}Eu and {sup 242m}Am for neutron energies from < 1eV up to {approx} 20 keV. We measured details of the {gamma}-ray cascade following neutron capture, for comparison with results of statistical model simulations. We determined the neutron energy dependent (n,{gamma}) cross section and gained information about statistical decaymore » properties, including the nuclear level density and the photon strength function. Because of the high granularity of the detector array, it is possible to look at gamma cascades with a specified number of transitions (a specific multiplicity). We simulated {gamma}-ray cascades using a combination of the DICEBOX/GEANT computer codes. In the case of the deformed nuclei, we found evidence of a scissors-mode resonance. For the Eu, we also determined the (n,{gamma}) cross sections. For the {sup 94,95}Mo, we focused on the spin and parity assignments of the resonances and the determination of the photon strength functions for the compound nuclei {sup 95,96}Mo. Future plans include measurements on actinide targets; our immediate interest is in {sup 242m}Am.« less

A Coupled Creep-Plasticity Model for Residual Stress Relaxation of a Shot-Peened Nickel-Base Superalloy

DTIC Science & Technology

2007-05-01

4 1e+5 1e+ 6 1000MPa... 6 1e-5 1e- 4 1e-3 1e-2 1e-1 1e-1 1e+0 1e+1 1e+2 1e+3 1e+ 4 1e+5 1e+ 6 1000MPa 900MPa 800MPa C re ep R at e (/s ) Creep Time (s) 0% Prestrain, 650°C...increase in strain rate. The change in deformation response is significant even for small plastic strains. 1e-9 1e-8 1e-7 1e- 6 1e-5 1e- 4 1e-3

Brain shift computation using a fully nonlinear biomechanical model.

PubMed

Wittek, Adam; Kikinis, Ron; Warfield, Simon K; Miller, Karol

2005-01-01

In the present study, fully nonlinear (i.e. accounting for both geometric and material nonlinearities) patient specific finite element brain model was applied to predict deformation field within the brain during the craniotomy-induced brain shift. Deformation of brain surface was used as displacement boundary conditions. Application of the computed deformation field to align (i.e. register) the preoperative images with the intraoperative ones indicated that the model very accurately predicts the displacements of gravity centers of the lateral ventricles and tumor even for very limited information about the brain surface deformation. These results are sufficient to suggest that nonlinear biomechanical models can be regarded as one possible way of complementing medical image processing techniques when conducting nonrigid registration. Important advantage of such models over the linear ones is that they do not require unrealistic assumptions that brain deformations are infinitesimally small and brain tissue stress-strain relationship is linear.

Elasticity and anelasticity of microcrystalline aluminum samples having various deformation and thermal histories

NASA Astrophysics Data System (ADS)

Betekhtin, V. I.; Kadomtsev, A. G.; Kardashev, B. K.

2006-08-01

The effect of the amplitude of vibrational deformation on the elastic modulus and internal friction of microcrystalline aluminum samples produced by equal-channel angular pressing was studied. The samples have various deformation and thermal histories. The elastic and inelastic (microplastic) properties of the samples are investigated. As the degree of plastic deformation increases, the Young’s modulus E, the amplitude-independent decrement δi, and the microplastic flow stress σ increase. As the annealing temperature increases, the quantities δi and σ decrease noticeably and the modulus E exhibits a more complex behavior. The experimental data are discussed under the assumption that the dislocation mobility depends on both the spectrum of point defects and the internal stresses, whose level is determined by the degree of plastic deformation and the temperature of subsequent annealing. The concept of internal stresses is also used to analyze the data on the effect of the degree of deformation and annealing on the rupture strength of the samples.

Cyclic Deformation and Fatigue of Monocrystalline Ni-Base Superalloys.

DTIC Science & Technology

1983-12-16

understanding crack nucleation (Laird et al at Pennsylvania, Fine et al at Northwestern, Neumann et al at Dusseldorf and Mughrabi et al at Stuttgart...hardened alloy in a project supported by the army. This work concentrated on the stability of precipitates under cyclic deformation ( Al -Ag, Al -Cu systems...and the strain-localization behavior of alloys containing shearable precipitates ( Al -Cu, e") and non-shearable precipitates ( Al -Cu, e’). Furthermore

{gamma}-vibrational states in superheavy nuclei

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun Yang; Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000; Joint Institute for Nuclear Astrophysics, University of Notre Dame, Notre Dame, Indiana 46556

2008-04-15

Recent experimental advances have made it possible to study excited structure in superheavy nuclei. The observed states have often been interpreted as quasiparticle excitations. We show that in superheavy nuclei collective vibrations systematically appear as low-energy excitation modes. By using the microscopic Triaxial Projected Shell Model, we make a detailed prediction on {gamma}-vibrational states and their E2 transition probabilities to the ground state band in fermium and nobelium isotopes where active structure research is going on, and in {sup 270}Ds, the heaviest isotope where decay data have been obtained for the ground-state and for an isomeric state.

Deformations of W A,D,E SCFTs

DOE PAGES

Intriligator, Ken; Nardoni, Emily

2016-09-08

We discuss aspects of theories with superpotentials given by Arnold’s A, D, E singularities, particularly the novelties that arise when the fields are matrices. We focus on 4d N=1 variants of susy QCD, with U(N c ) or SU(N c ) gauge group, N f fundamental flavors, and adjoint matter fields X and Y appearing in W A,D,E (X, Y) superpotentials. Many of our considerations also apply in other possible contexts for matrix-variable W A,D,E . The 4d W A,D,E SQCD-type theories RG flow to superconformal field theories, and there are proposed duals in the literature for the W Ak,more » W Dk, and W E7 cases. As we review, the W Deven and W E7 duals rely on a conjectural, quantum truncation of the chiral ring. We explore these issues by considering various deformations of the W A,D,E superpotentials, and the resulting RG flows and IR theories. Rather than finding supporting evidence for the quantum truncation and W Deven and W E7 duals, we note some challenging evidence to the contrary.« less

New constraints on the Pan-African tectonics and the role of the Mwembeshi Zone in Central Zambia: Deformation style and timing of two orthogonal shortening events

NASA Astrophysics Data System (ADS)

Naydenov, Kalin; Lehmann, Jeremie; Saalmann, Kerstin; Milani, Lorenzo; Kinnaird, Judith; Charlesworth, Guy; Rankin, William; Frei, Dirk

2014-05-01

In Central Zambia the Mwembeshi Zone (MwZ) separates two branches of the Late Neoproterozoic - Cambrian Pan-African Orogen: the NE-convex Lufilian Arc and the E-W trending Zambezi Belt whose distinct features emphasize the role of the zone as a regional structural and metamorphic boundary. North of the MwZ, the Hook Batholith was emplaced within the low metamorphic grade Neoproterozoic metasedimentary rocks, and represents the largest Pan-African intrusion in Southern Africa. The granitoids and their host-rocks were affected by two deformation events. During the D1 deformation of E-W shortening, two high-strained zones developed in the batholith. To the NE, the Nalusanga Zone (NZ) is a ~3 km wide NW-striking subvertical sinistral strike-slip shear zone. To the SW, a ~2.5 km wide N-S trending subvertical pure-shear Itezhi-Tezhi Zone (ITZ) formed. In both structures, the granitoids show a smooth transition from weakly deformed rocks to porphyroclastic mylonites. Microstructural analysis defined them as medium metamorphic grade zones, deforming the granitoids at temperatures between 500 and 550°C. The lower greenschist facies metamorphism in the country rocks indicates that the deformation occurred during the cooling of the granitoids. D1 in the metasedimentary rocks east of the Hook batholith formed tight, upright folds with subvertical axial-planar cleavage and NNW-SSE trending axis consistent with the E-W shortening. U-Pb zircon geochronology and cross-cutting relationships between granites bracket D1 deformation between 549 ± 2 Ma and 541 ± 3 Ma in the NZ and in the SE part of the batholith. In the ITZ, the 533 ± 3 Ma age on a deformed granite indicates prolonged E-W shortening during granite emplacement and cooling history. D2 represents a stage of N-S shortening. Airborne geophysical data revealed bending of the N-S trending ITZ and rotation to the east. The D1 structures in the granitoids are cut by D2 north-vergent thrusts and subvertical NW trending dextral strike-slip zones. East of the granite, D2 resulted in E-W trending open folds that refolded the D1 structures. This folding becomes more intense and the folds are tighter when approaching the MwZ to the south. Along the MwZ, the molasse rocks, deposited after D1 (post ~528 Ma, based on new detrital-zircon ages), recorded high-strain greenschist facies coaxial deformation and the formation of E-W trending isoclinal folds with a steep south-dipping axial planar cleavage. This study shows that the area north of the MwZ is characterised by two orthogonal contraction events. The newly described D1 event of E-W shortening in the Hook area cannot be correlated with any of the published Pan-African tectonic models for the Lufilian Arc and Zambezi Belt. The D2 event of N-S shortening affected the region in response to the final docking between the Lufilian Arc and the Zambezi Belt. The strongest effect of this event was observed along the MwZ, which, during this stage, was a zone of intense coaxial deformation.

Stability of superheavy nuclei

NASA Astrophysics Data System (ADS)

Pomorski, K.; Nerlo-Pomorska, B.; Bartel, J.; Schmitt, C.

2018-03-01

The potential-energy surfaces of an extended set of heavy and superheavy even-even nuclei with 92 ≤Z ≤126 and isospins 40 ≤N -Z ≤74 are evaluated within the recently developed Fourier shape parametrization. Ground-state and decay properties are studied for 324 different even-even isotopes in a four-dimensional deformation space, defined by nonaxiality, quadrupole, octupole, and hexadecapole degrees of freedom. Nuclear deformation energies are evaluated in the framework of the macroscopic-microscopic approach, with the Lublin-Strasbourg drop model and a Yukawa-folded mean-field potential. The evolution of the ground-state equilibrium shape (and possible isomeric, metastable states) is studied as a function of Z and N . α -decay Q values and half-lives, as well as fission-barrier heights, are deduced. In order to understand the transition from asymmetric to symmetric fission along the Fm isotopic chain, the properties of all identified fission paths are investigated. Good agreement is found with experimental data wherever available. New interesting features about the population of different fission modes for nuclei beyond Fm are predicted.

Annihilation of Antiprotons in Heavy Nuclei.

DTIC Science & Technology

1986-04-01

Scattering Models, Acta Physica Polonica 1311, 425 (1980). T.E. Kalogeropoalos, L. Gray, A . Nandy, and J. Roy, Antiproton-nucleon Annihilation into...I th a Rpor Annihilation of AntiprotonsI the period ,- tpril 1985 to in Heavy Nuclei December 1985 April 1986 Author: Lawrence Livermore National...will be available to the general public, including foreign nationals. A ~AY 2 - >i K2U~ prepared for the: Air Force Rocket Propulsion Laboratory Air

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miyao, Tadahiro; Spohn, Herbert

The retarded van der Waals potential, as first obtained by Casimir and Polder, is usually computed on the basis of nonrelativistic quantum electrodynamics . The Hamiltonian describes two infinitely heavy nuclei, charge e, separated by a distance R and two spinless electrons, charge -e, nonrelativistically coupled to the quantized radiation field. Casimir and Polder used the dipole approximation and small coupling to the Maxwell field. We employ here the full Hamiltonian and determine the asymptotic strength of the leading -R{sup -7} potential, which is valid for all e. Our computation is based on a path integral representation and expands inmore » 1/R, rather than in e.« less

Quantization of Differences Between Atomic and Nuclear Rest Masses and Self-organization of Atoms and Nuclei

NASA Astrophysics Data System (ADS)

Gareev, F. A.; Zhidkova, I. E.

2007-03-01

We come to the conclusion that all atomic models based on either the Newton equation and the Kepler laws, or the Maxwell equations, or the Schrodinger and Dirac equations are in reasonable agreement with experimental data. We can only suspect that these equations are grounded on the same fundamental principle(s) which is (are) not known or these equations can be transformed into each other. We proposed a new mechanism of LENR: cooperative processes in the whole system nuclei + atoms + condensed matter - nuclear reactions in plasma - can occur at smaller threshold energies than the corresponding ones on free constituents. We were able to quantize phenomenologically the first time the differences between atomic and nuclear rest masses by the formula: δδM =n1/n2 X 0.0076294 (in MeV/ c^2), ni=1,2,3,.... Note that this quantization rule is justified for atoms and nuclei with different A, N and Z and the nuclei and atoms represent a coherent synchronized systems - a complex of coupled oscillators (resonators). The cooperative resonance synchronization mechanisms can explain how electron volt (atomic-) scale processes can induce and control nuclear MeV (nuclear-) scale processes and reactions., F.A. Gareev, I.E. Zhidkova, E-print arXiv Nucl-th/ 0610002 2006.

Wave Propagation and Dynamics of Lattice Structures.

DTIC Science & Technology

1984-05-01

Progress in Solid Mechanics, North Holand Publishing Company, Amsterdam, 1960. [7) Y. K. Linn, and T. J. McDaniel, ’n)amics of Beam Type Periodic...deformation. -99- APPENDIX F FREQUENCY RESPONSE AND IMPULSE RESPONSE FUNCTIONS FOR LONGITUDINAL VIBRATION IN AN ELASTIC ROD Figure F1 shows the elastic rod to b...6 (F38) Rearranging eqn. (F38), .HE(w) = e’ 4e~3 ~e e 2 e1" +e " 6 e r (F39) Mlultiplying eqn. ( F1 =39) by 6Ŕ 6- and aragn te - . e 6 -e _ aix

Microscopic Shell Model Calculations for sd-Shell Nuclei

NASA Astrophysics Data System (ADS)

Barrett, Bruce R.; Dikmen, Erdal; Maris, Pieter; Shirokov, Andrey M.; Smirnova, Nadya A.; Vary, James P.

Several techniques now exist for performing detailed and accurate calculations of the structure of light nuclei, i.e., A ≤ 16. Going to heavier nuclei requires new techniques or extensions of old ones. One of these is the so-called No Core Shell Model (NCSM) with a Core approach, which involves an Okubo-Lee-Suzuki (OLS) transformation of a converged NCSM result into a single major shell, such as the sd-shell. The obtained effective two-body matrix elements can be separated into core and single-particle (s.p.) energies plus residual two-body interactions, which can be used for performing standard shell-model (SSM) calculations. As an example, an application of this procedure will be given for nuclei at the beginning ofthe sd-shell.

MC generator HARDPING: Nuclear effects in hard interactions of leptons and hadrons with nuclei

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berdnikov, Ya. A.; Ivanov, A. E.; Kim, V. T.

2016-01-22

Hadron and lepton production in hard interaction of high-energy particles with nuclei are considered in context of developing of Monte Carlo generator HARDPING (Hard Probe Interaction Generator). Such effects as energy losses and multiple re-scattering initial and produced hadrons and their constituents are taken into account. These effects are implemented in current version of generator HARDPING. Data of experiments HERMES on hadron production in lepton-nuclei collisions and E866 on muon pair production in proton-nuclei collisions were described with current version of generator HARDPING. Predictions from recent version HARPING 3.0 for lepton pairs production at proton beam energy I20 GeV aremore » presented.« less

β4 systematics in rare-earth and actinide nuclei: sdg interacting boson model description

NASA Astrophysics Data System (ADS)

Devi, Y. D.; Kota, V. K. B.

1992-07-01

The observed variation of hexadecupole deformation parameter β4 with mass number A in rare-earth and actinide nuclei is studied in the sdg interacting boson model (IBM) using single j-shell Otsuka-Arima-Iachello mapped and IBM-2 to IBM-1 projected hexadecupole transition operator together with SUsdg(3) and SUsdg(5) coherent states. The SUsdg(3) limit is found to provide a good description of data.

Komar energy and Smarr formula for noncommutative inspired Schwarzschild black hole

NASA Astrophysics Data System (ADS)

Banerjee, Rabin; Gangopadhyay, Sunandan

2011-11-01

We calculate the Komar energy E for a noncommutative inspired Schwarzschild black hole. A deformation from the conventional identity E = 2 ST H is found in the next to leading order computation in the noncommutative parameter θ (i.e. {{O}(sqrt{θ}e^{-M^2/θ})}) which is also consistent with the fact that the area law now breaks down. This deformation yields a nonvanishing Komar energy at the extremal point T H = 0 of these black holes. We then work out the Smarr formula, clearly elaborating the differences from the standard result M = 2 ST H , where the mass ( M) of the black hole is identified with the asymptotic limit of the Komar energy. Similar conclusions are also shown to hold for a deSitter-Schwarzschild geometry.

Spatial and Temporal Characteristics of Land Deformation in Northern Saudi Arabia: Inferences from Radar Interferometric Applications

NASA Astrophysics Data System (ADS)

Othman, A.; Sultan, M.; Gebremichael, E.; Sefry, S.; Yanar, R.; Alharbi, H.; Albalawi, S.; Emil, M. K.; Pankratz, H. G.

2016-12-01

Over the past two decades, land deformation phenomena and related losses in public and private property were reported from the northern part of the Kingdom of Saudi Arabia in Al Jowf region (100,212 km²; from lat: 29.25°N to 30.90°N, from long: 37.60°E to 40.70°E). We applied an integrated approach (geotechnical, geology, remote sensing, geodesy, hydrogeology, and GIS) to identify areas affected by these phenomena, quantify the nature and magnitude of deformation, investigate the factors controlling the deformation, and recommend solutions for these problems. We applied a three-fold approach in three different areas (Alisawiyah, Wadi Alsarhan, and Sakaka areas) to accomplish the following: (1) assess the spatial distribution of land deformation and quantify deformation rates using InSAR methods Persistent Scatterer Interferometry (PSI) and Small BAseline Subsets (SBAS); (2) generate a GIS database to encompass all relevant data and derived products (e.g., remote sensing, geology, geotechnical, GPS, groundwater extraction rates, distribution of urban areas, etc.), and (3) correlate findings from the InSAR exercise with relevant spatial and temporal datasets in search of causal effects. Findings revealed the following: (1) high and consistent subsidence rates (5 to 13 mm/yr) from multiple interferometric techniques; (2) subsided areas correlated largely with the distribution of irrigated agricultural land over alluvial and unconfined aquifers (e.g., Tawil and Jauf aquifers), areas characterized by high and a progressive increase in groundwater extraction (1.2 bcm/yr) as evidenced from the satellite-based temporal distribution of irrigated lands (area irrigated lands: 1998: 37,737 ha; 2013: 70,869 ha); (3) high subsidence rates ( 8 mm/yr) were also detected over urban areas (e.g., Sakaka, Dumat Aljandal, and Tubarjal ), subsidence being caused by disposal of wastewater in the subsurface leading to rise in water tables, dissolution of substrate rocks/sediments (e.g., carbonates, evaporates, sabkhas), and settling of buildings and infrastructures; (4) presence of numerous sinkholes within the Aruma formation (limestone and dolomite) that appear as incoherent circular domains (diameter range: 20 to 50 m) on the derived radar products within subsiding areas (subsidence rates: up to 6 mm/yr).

Biological Ice Nuclei: They are Everywhere, What are Their Roles? (Invited)

NASA Astrophysics Data System (ADS)

Schnell, R. C.

2009-12-01

Biological ice nuclei active at temperatures warmer than -2C were first observed in the late 1960s associated with decaying grass and tree leaves; discovered more by accident than in a planned experiment. The active component of the decaying leaves was subsequently found to be produced by a few living bacteria, the two most ubiquitous being strains of P. syringae and E. herbicola. The active bacterial ice nuclei are easily deactivated by anaerobic, chemical and heat stresses. The same grass and tree leaves, when well decayed, generally contain less active ice nuclei (threshold temperatures of -5C to - 6C) in the 0.1 micron diameter range compared to the larger (1 micron) bacteria associated ice nuclei. The well decayed leaf litter ice nuclei are stable over a wide range of stresses and time; some samples of leaf derived nuclei stored at room temperature have exhibited the same ice nucleus concentration for over 30 years. Fungi also have active ice nuclei that are stable over many decades. Active ice nuclei are found in marine waters associated with plankton, and are produced by at least one marine dinoflagellate (Heterocapsa niei) that expresses ice nucleus activity almost as warm as terrestrial bacteria ice nuclei. Living ice nucleus bacteria have been found in marine fogs far at sea, in precipitation in Antarctica as well as over many continental areas, in air in the high Arctic, on vegetation around the world, on remote ice bound islands, and growing on and inside water storing vegetation on isolated tropical mountain peaks. But why? What is the evolutionary advantage for the ice nucleus gene to be expressed in such a wide range of environments, by greatly different species? There is an energy cost for bacteria and fungi to support the ice gene, so it probably is not a genetic anomaly. Possibly the ice nuclei play many roles? These could include damaging plants to acquire a food source, an aid in survival and dispersal in clouds, initiation of precipitation to help plant growth, initiating ice formation and subsequent scavenging of water vapor in cold climates (e.g. Arctic and high elevation lichen), living in symbiosis with high elevation vegetation that freezes nightly, and probably a range of others we have not observed or yet hypothesized. Bacterial ice nucleation is truly an intriguing and fantastic phenomenon for which we have just begun to understand.

Influence of deformed surface diffuseness on alpha decay half-lives of actinides and lanthanides

NASA Astrophysics Data System (ADS)

Dahmardeh, S.; Alavi, S. A.; Dehghani, V.

2017-07-01

By using semiclassical WKB method and taking into account the Bohr-Sommerfeld quantization condition, the alpha decay half-lives of some deformed lanthanide (with 151 ≤ A ≤ 160 and 66 ≤ Z ≤ 73) and rare-earth nuclei (with 217 ≤ A ≤ 261 and 92 ≤ Z ≤ 104) have been calculated. The effective potential has been considered as sum of deformed Woods-Saxon nuclear potential, deformed Coulomb potential, and centrifugal potential. The influence of deformed surface diffuseness on the potential barrier, transmission coefficient at each angle, assault frequency, and alpha decay half-lives has been investigated. Good agreement between calculated half-lives with deformed surface diffuseness and experiment is observed. Relative differences between calculated half-lives with deformed surface diffuseness and with constant surface diffuseness were significant.

Teleseismic shear-wave splitting in SE Tibet: Insight into complex crust and upper-mantle deformation

NASA Astrophysics Data System (ADS)

Huang, Zhouchuan; Wang, Liangshu; Xu, Mingjie; Ding, Zhifeng; Wu, Yan; Wang, Pan; Mi, Ning; Yu, Dayong; Li, Hua

2015-12-01

We measured shear-wave splitting of teleseismic XKS phases (i.e., SKS, SKKS and PKS) recorded by more than 300 temporary ChinArray stations in Yunnan of SE Tibet. The first-order pattern of XKS splitting measurements shows that the fast polarization directions (φ) change (at ∼26-27°N) from dominant N-S in the north to E-W in the south. While splitting observations around the eastern Himalayan syntax well reflect anisotropy in the lithosphere under left-lateral shear deformation, the dominant E-W φ to the south of ∼26°N is consistent with the maximum extension in the crust and suggest vertically coherent pure-shear deformation throughout the lithosphere in Yunnan. However, the thin lithosphere (<80 km) could account for only part (<0.7 s) of the observed splitting delay times (δt, 0.9-1.5 s). Anisotropy in the asthenosphere is necessary to explain the NW-SE and nearly E-W φ in these regions. The NE-SW φ can be explained by the counter flow caused by the subduction and subsequent retreat of the Burma slab. The E-W φ is consistent with anisotropy due to the absolute plate motion in SE Tibet and the eastward asthenospheric flow from Tibet to eastern China accompanying the tectonic evolution of the plateau. Our results provide new information on different deformation fields in different layers under SE Tibet, which improves our understanding on the complex geodynamics related to the tectonic uplift and southeastward expansion of Tibetan material under the plateau.

Multifractal Analysis of Seismically Induced Soft-Sediment Deformation Structures Imaged by X-Ray Computed Tomography

NASA Astrophysics Data System (ADS)

Nakashima, Yoshito; Komatsubara, Junko

Unconsolidated soft sediments deform and mix complexly by seismically induced fluidization. Such geological soft-sediment deformation structures (SSDSs) recorded in boring cores were imaged by X-ray computed tomography (CT), which enables visualization of the inhomogeneous spatial distribution of iron-bearing mineral grains as strong X-ray absorbers in the deformed strata. Multifractal analysis was applied to the two-dimensional (2D) CT images with various degrees of deformation and mixing. The results show that the distribution of the iron-bearing mineral grains is multifractal for less deformed/mixed strata and almost monofractal for fully mixed (i.e. almost homogenized) strata. Computer simulations of deformation of real and synthetic digital images were performed using the egg-beater flow model. The simulations successfully reproduced the transformation from the multifractal spectra into almost monofractal spectra (i.e. almost convergence on a single point) with an increase in deformation/mixing intensity. The present study demonstrates that multifractal analysis coupled with X-ray CT and the mixing flow model is useful to quantify the complexity of seismically induced SSDSs, standing as a novel method for the evaluation of cores for seismic risk assessment.

Broadscale postseismic deformation and lower crustal relaxation in the central Bayankala Block (central Tibetan Plateau) observed using InSAR data

NASA Astrophysics Data System (ADS)

Zhao, Dezheng; Qu, Chunyan; Shan, Xinjian; Zuo, Ronghu; Liu, Yunhua; Gong, Wenyu; Zhang, Guohong

2018-04-01

We have generated a more than 500 km long postseismic deformation rate map and cumulative displacement time series in the central Bayankala Block of the Tibetan Plateau using ENVISAT/ASAR data from 2003 to 2010 by the π-RATE stacking algorithm. This rate map spans a period of ∼7.2 years and reveals that postseismic motion of 2001 Kokoxili earthquake exhibits a striking signal, dominating crustal deformation of the central Bayankala Block with a cross-fault magnitude ∼9-11 mm/yr in line of sight (LOS) (∼93.1°E). The southern and northern parts of the postseismic deformation field exhibit different patterns and variable magnitudes, reflecting asymmetry of the displacement distribution. Postseismic motion affects eastward extrusion of the central Bayankala Block, which reaches ∼15 km north of the Ganzi-Yushu fault. To further investigate viscoelastic relaxation of the lower crust in this area after approximately two years, E-M, E-M-M and E-S models are constructed. The result shows that the best fit viscosity for the lower crust is about 1 × 1019 Pa·s. Comparison between cumulative displacements resolved by these three models shows that viscoelastic relaxation of the lower crust makes the most significant contribution to postseismic stress relaxation after 2001 event.

The Long Adventurous Journey of Rhombic Lip Cells in Jawed Vertebrates: A Comparative Developmental Analysis

PubMed Central

Wullimann, Mario F.; Mueller, Thomas; Distel, Martin; Babaryka, Andreas; Grothe, Benedikt; Köster, Reinhard W.

2011-01-01

This review summarizes vertebrate rhombic lip and early cerebellar development covering classic approaches up to modern developmental genetics which identifies the relevant differential gene expression domains and their progeny. Most of this information is derived from amniotes. However, progress in anamniotes, particularly in the zebrafish, has recently been made. The current picture suggests that rhombic lip and cerebellar development in jawed vertebrates (gnathostomes) share many characteristics. Regarding cerebellar development, these include a ptf1a expressing ventral cerebellar proliferation (VCP) giving rise to Purkinje cells and other inhibitory cerebellar cell types, and an atoh1 expressing upper rhombic lip giving rise to an external granular layer (EGL, i.e., excitatory granule cells) and an early ventral migration into the anterior rhombencephalon (cholinergic nuclei). As for the lower rhombic lip (LRL), gnathostome commonalities likely include the formation of precerebellar nuclei (mossy fiber origins) and partially primary auditory nuclei (likely convergently evolved) from the atoh1 expressing dorsal zone. The fate of the ptf1a expressing ventral LRL zone which gives rise to (excitatory cells of) the inferior olive (climbing fiber origin) and (inhibitory cells of ) cochlear nuclei in amniotes, has not been determined in anamniotes. Special for the zebrafish in comparison to amniotes is the predominant origin of anamniote excitatory deep cerebellar nuclei homologs (i.e., eurydendroid cells) from ptf1a expressing VCP cells, the sequential activity of various atoh1 paralogs and the incomplete coverage of the subpial cerebellar plate with proliferative EGL cells. Nevertheless, the conclusion that a rhombic lip and its major derivatives evolved with gnathostome vertebrates only and are thus not an ancestral craniate character complex is supported by the absence of a cerebellum (and likely absence of its afferent and efferent nuclei) in jawless fishes PMID:21559349

The role of major rift faults in the evolution of deformation bands in the Rio do Peixe Basin, Brazil

NASA Astrophysics Data System (ADS)

Hilario Bezerra, Francisco; Araujo, Renata; Maciel, Ingrid; Cezar Nogueira, Francisco; Balsamo, Fabrizio; Storti, Fabrizio; Souza, Jorge Andre; Carvalho, Bruno

2017-04-01

Many studies have investigated on the evolution and properties of deformation bands, but their occurrence and relationships with basin-boundary faults remain elusive when the latter form by brittle reactivation of structural inheritance in crystalline basements. The main objective of our study was to systematically record the location, kinematics, geometry, and density of deformation bands in the early Cretaceous Rio do Peixe basin, NE Brazil, and analyze their relationship with major syn-rift fault zones. Reactivation in early Cretaceous times of continental-scale ductile shear zones led to the development of rift basins in NE Brazil. These shear zones form a network of NE- and E-W-trending structures hundreds of kilometers long and 3-10 km wide. They were active in the Brasiliano orogeny at 540-740 Ma. Brittle reactivation of these structures occurred in Neocomian times ( 140-120 Ma) prior the breakup between the South American and African plates in the late Cretaceous. The Rio do Peixe basin formed at the intersection between the NE-SW-striking Portalegre shear zone and the E-W-striking Patos shear zone. The brittle fault systems developed by the shear zone reactivation are the Portalegre Fault and the Malta Fault, respectively. In this research we used field structural investigations and drone imagery with centimetric resolution. Our results indicate that deformation bands occur in poorly sorted, medium to coarse grain size sandstones and localize in 3-4 km wide belts in the hanging wall of the two main syn-rifts fault systems. Deformation bands formed when sandstones were not completely lithified. They strike NE along the Portalegre Fault and E-W along the Malta Fault and have slip lineations with rake values ranging from 40 to 90. The kinematics recorded in deformation bands is consistent with that characterizing major rift fault systems, i.e. major extension with a strike-slip component. Since deformations bands are typical sub-seismic features, our findings can have implications for the prediction of deformation band occurrence in sedimentary basins and their geometric and kinematic relations with major basin-boundary fault systems.

Microscopic insight into the structure of gallium isotopes

NASA Astrophysics Data System (ADS)

Verma, Preeti; Sharma, Chetan; Singh, Suram; Bharti, Arun; Khosa, S. K.

2012-07-01

Projected Shell Model technique has been applied to odd-A71-81Ga nuclei with the deformed single-particle states generated by the standard Nilsson potential. Various nuclear structure quantities have been calculated with this technique and compared with the available experimental data in the present work. The known experimental data of the yrast bands in these nuclei are persuasively described and the band diagrams obtained for these nuclei show that the yrast bands in these odd-A Ga isotopes don't belong to the single intrinsic state only but also have multi-particle states. The back-bending in moment of inertia and the electric quadrupole transitions are also calculated.

Patient-specific non-linear finite element modelling for predicting soft organ deformation in real-time: application to non-rigid neuroimage registration.

PubMed

Wittek, Adam; Joldes, Grand; Couton, Mathieu; Warfield, Simon K; Miller, Karol

2010-12-01

Long computation times of non-linear (i.e. accounting for geometric and material non-linearity) biomechanical models have been regarded as one of the key factors preventing application of such models in predicting organ deformation for image-guided surgery. This contribution presents real-time patient-specific computation of the deformation field within the brain for six cases of brain shift induced by craniotomy (i.e. surgical opening of the skull) using specialised non-linear finite element procedures implemented on a graphics processing unit (GPU). In contrast to commercial finite element codes that rely on an updated Lagrangian formulation and implicit integration in time domain for steady state solutions, our procedures utilise the total Lagrangian formulation with explicit time stepping and dynamic relaxation. We used patient-specific finite element meshes consisting of hexahedral and non-locking tetrahedral elements, together with realistic material properties for the brain tissue and appropriate contact conditions at the boundaries. The loading was defined by prescribing deformations on the brain surface under the craniotomy. Application of the computed deformation fields to register (i.e. align) the preoperative and intraoperative images indicated that the models very accurately predict the intraoperative deformations within the brain. For each case, computing the brain deformation field took less than 4 s using an NVIDIA Tesla C870 GPU, which is two orders of magnitude reduction in computation time in comparison to our previous study in which the brain deformation was predicted using a commercial finite element solver executed on a personal computer. Copyright © 2010 Elsevier Ltd. All rights reserved.

Measuring the B(E2) of the 1/2- ->3/2- transition in 7 Be

NASA Astrophysics Data System (ADS)

Henderson, S. L.; Ahn, T.; Caprio, M. A.; Constantinou, Ch.; Simon, A.; Twinsol Collaboration

2017-09-01

Ab-initio methods have been successful in describing the structure of light nuclei using realistic nucleon-nucleon interactions, but more experimental data is needed for light unstable nuclei. Recent no-core configuration interaction calculations have made predictions for the ratio of E2 transition strengths for the first excited state transition in 7 Be and 7 Li . Additional calculations that include clustering effects show a significant difference in the 7 Be and 7 Li B(E2) value. The E2 transition strength of the 7 Be first excited state has never been measured, which provides an interesting opportunity to investigate the accuracy of these calculations. To measure this E2 transition strength, a Coulomb Excitation experiment was performed at the University of Notre Dame. 7 Be was produced and separated using TwinSol. A beam of 7 Be ions were scattered off a gold target and the gamma rays from the inelastically scattered ions were detected using six clover Ge detectors. The most recent results for the E2 transition strength and its comparison to the no-core configuration interaction approach will be shown. In addition, new systematic checks on the experiment will be presented including the first stages of a Geant4 simulation to help account for beam anisotropies. This work has been supported by US NSF Grant No. PHY 14-19765 and DOE Grant Number DE-FG02-95ER-40934.

Testing the QGSJET01 and QGSJETII-04 models with the help of atmospheric muons

NASA Astrophysics Data System (ADS)

Dedenko, Leonid G.; Lukyashin, Anton V.; Roganova, Tatiana M.; Fedorova, Galina F.

2017-06-01

More accurate original calculations of the atmospheric vertical muon energy spectra at energies 102 - 105 GeV have been carried out in terms of the QGSJET01 and QGSJETII-04 models. The Gaisser-Honda approximations of the measured energy spectra of primary protons, helium and nitrogen nuclei have been used. The CORSIKA package has been used to simulate cascades in the standard atmosphere induced by different primary particles with various fixed energies E. Statistics of simulated cascades for secondary particles with energies (0.01 - 1) · E was increased up to 106. It has been shown that predictions of the QGSJET01 and QGSJETII-04 models for these muon fluxes are below the data of the classical experiments L3 + Cosmic, MACRO and LVD by factors of ˜ 1.7-2 at energies above 102 GeV. It has been concluded that these tested models underestimate the production of the most energetic secondary particles, namely, π-mesons and K-mesons, in interactions of primary protons and other primary nuclei with nuclei in the atmosphere by the same factors.

Testing of the DPMJET and VENUS hadronic interaction models with help of the atmospheric muons

NASA Astrophysics Data System (ADS)

Dedenko, L. G.; Lukyashin, A. V.; Roganova, T. M.; Fedorova, G. F.

2017-01-01

The more accurate original calculations of the atmospheric vertical muon energy spectra at energies 102 - 105 GeV have been carried out in terms of DPMJET and VENUS models. The Gaisser-Honda approximations of the measured energy spectra of primary protons, helium and nitrogen nuclei have been used. The package CORSIKA has been used to simulate cascades in the standard atmosphere induced by different primary particles with various fixed energies E. Statistics of simulated cascades for secondary particles with energies (0.01-1)·E was increased up to 106. It has been shown that predictions of the DPMJET and VENUS models for these muon fluxes are below the data of the classical experiments L3 + Cosmic, MACRO and LVD by factors of ˜ 1.6-1.95 at energies above 102 GeV. It has been concluded that these tested models underestimate the production of the most energetic secondary particles, namely, π-mesons and K-mesons, in interactions of the primary protons and other primary nuclei with nuclei in the atmosphere by the same factors.

Nuclear Structure Studies with Radioactive Ion Beams in the Mass A = 80 Region

NASA Astrophysics Data System (ADS)

Galindo-Uribarri, A.; Padilla-Rodal, E.; Batchelder, J. C.; Beene, J. R.; Lagergren, K. B.; Mueller, P. E.; Radford, D. C.; Stracener, D. W.; Urrego-Blanco, J. P.; Varner, R. L.; Yu, C.-H.

2009-03-01

An experimental program to measure spectroscopic properties of neutron-rich nuclei in the A = 80 region is underway at the Holifield Radioactive Ion Beam Facility. Our approach has been to get a comprehensive picture of the shell structure in this region by studying a series of properties of low lying states (E(2+), B(E2), g-factors and quadrupole moments). The beams, instrumentation and techniques developed specifically for this purpose have allowed us to systematically study the behavior of these observables along isotopic and isotonic chains using both stable and radioactive nuclei under almost identical experimental conditions. We have developed many techniques and detectors for in-beam gamma spectroscopy with radioactive ion beams. Most of the detectors can be used individually or in combination. Generally these detector systems have very large efficiencies. We give examples of their use from three recent experiments; namely, Coulomb excitation of n-rich nuclei along the N = 50 shell closure, the static quadrupole moment of the first 2+ in 78Ge and g-factor measurements of n-rich isotopes near N = 50.

The Heavy Nuclei eXplorer (HNX) Mission

NASA Astrophysics Data System (ADS)

Krizmanic, John; Mitchell, John; Binns, W. Robert; Hams, Thomas; Israel, Martin; Link, Jason; Rauch, Brian; Sakai, Kenichi; Sasaki, Makoto; Westphal, Andrew; Wiedenbeck, Mark; Heavy Nuclei eXplorer Collaboration

2016-03-01

The Heavy Nuclei eXplorer (HNX) will use two large high-precision instruments, the Extremely-heavy Cosmic-ray Composition Observer (ECCO) and the Cosmic-ray Trans-Iron Galactic Element Recorder (CosmicTIGER), designed to fly in a SpaceX DragonLab Capsule, to measure the cosmic-ray abundance of every individual element in the periodic table from carbon through curium, providing the first measurement of many of these elements. These measurements provide an investigation on the nature of the source material of cosmic rays, the processes that inject them into cosmic accelerators, and the acceleration mechanisms. HNX will measure several thousand ultra-heavy galactic cosmic ray (UHGCR) nuclei with Z >= 30 , including about 50 actinides (Z >= 79). These data allow for a measurement of the mix of new and old material that is accelerated to GCRs, determine their age, measure the mix of nucleosynthesis processes responsible for the UHGCRs, determine how UHGCR elements are selected for acceleration, and measure the mean integrated pathlength traversed by UHGCRs before observation. The scientific motivation and instrumentation of HNX will be discussed as well as recent beam test results.

Do predators cause frog deformities? The need for an eco-epidemiological approach.

PubMed

Johnson, Pieter T J; Bowerman, Jay

2010-11-15

Renewed controversy has emerged over the likely causes and consequences of deformed amphibians, particularly those with missing limbs. The results of a series of experiments by Ballengée and Sessions (2009) implicate aquatic predators (i.e. dragonfly larvae) in causing such abnormalities. Skelly and Benard (2010), however, argued that the small scale of these experiments and the absence of a correlation between predator abundance and deformity frequencies in natural amphibian populations undermine such a conclusion. Drawing upon our experiences with frog malformations, we suggest that the study of amphibian deformities has been hindered by two, interrelated problems. First, empirical studies often fail to critically define the expected baseline level of abnormalities and differentiate between "epidemic" and "endemic" frequencies of malformations. Second, recognizing the likelihood of multiple causes in driving amphibian malformations, continued research needs to embrace a "multiple lines of evidence" approach that allows for complex etiologies by integrating field surveys, diagnostic pathology, comparative modeling, and experiments across a range of ecological scales. We conclude by highlighting the results of a recent study that uses this approach to identify the role of aquatic predators (i.e., fishes and dragonflies) in causing high frequencies of deformed frogs in Oregon. By combining long-term data, comparative data and mechanistic experiments, this study provides compelling evidence that certain predators do cause deformities under ecologically relevant conditions. In light of continuing concerns about amphibian deformities and population declines, we emphasize the need to integrate ecological, epidemiological, and developmental tools in addressing such environmental enigmas. Copyright © 2010 Wiley-Liss, Inc., A Wiley Company.

The Spectrum of Scalar Indices of Agyrotropy

NASA Astrophysics Data System (ADS)

Scudder, J. D.; Daughton, W. S.

2017-12-01

Quantitative scalar measures of departures from gyrotropy will be contrasted using 3D-PIC guide field simulations of a reconnection layer. Of interest are the sensitivity of 4 different proposed methods for inventorying the occurrence of needed signatures of demagnetization for identification of reconnection sites. Visual maps will be presented using the originally formulated diagnostic A0e for agyrotropy and three relatively recent attempts to generalize it. These visuals highlight the essentially common information contained in these approaches. The ``flavor'' distinctions between these techniques will be organized in terms of the types of deformations of the eVDF required for their distinctions to be present/significant. The first class of disturbances are those that explicitly cause the eVDF to depend on gyro phase in addition to pitch angle, while the second class requires a strong coordinated deformation of the eVDF in both polar angles. In the first class the magnetic field remains as an eigenvector of the deformed pressure tensor as in the originally proposed diagnostic A0e; in the second class NO eigenvector is aligned with the magnetic field and accompanies a more violent disruption of magnetization than the first class. The 3D VPIC guide simulation will be used as a data base to show the relative frequency of occurrence of these two types of disruptions in regions with non-zero agyrotropy. As far as identifying whether a region has demagnetization or not all techniques are virtually interchangeable and are shown to be statistically strongly correlated using billions of estimates. Accordingly, extensive early surveys using A0e to survey PIC reconnection geometries for signatures of demagnetization are not supplanted by the existence of alternate recipes for quantifying the geometry of the pressure tensor that get slightly larger values in relatively esoteric circumstances. Of the two types of deformation of the eVDF required to produce different ``flavors'' of agyrotropy, the gyro phase only modulations resolved completely by A0e are statistically the more common instances of demagnetization in 3D-PIC simulations.

The N-Terminal Amphipathic Helix of the Topological Specificity Factor MinE Is Associated with Shaping Membrane Curvature

PubMed Central

Shih, Yu-Ling; Huang, Kai-Fa; Lai, Hsin-Mei; Liao, Jiahn-Haur; Lee, Chai-Siah; Chang, Chiao-Min; Mak, Huey-Ming; Hsieh, Cheng-Wei; Lin, Chu-Chi

2011-01-01

Pole-to-pole oscillations of the Min proteins in Escherichia coli are required for the proper placement of the division septum. Direct interaction of MinE with the cell membrane is critical for the dynamic behavior of the Min system. In vitro, this MinE-membrane interaction led to membrane deformation; however, the underlying mechanism remained unclear. Here we report that MinE-induced membrane deformation involves the formation of an amphipathic helix of MinE2–9, which, together with the adjacent basic residues, function as membrane anchors. Biochemical evidence suggested that the membrane association induces formation of the helix, with the helical face, consisting of A2, L3, and F6, inserted into the membrane. Insertion of this helix into the cell membrane can influence local membrane curvature and lead to drastic changes in membrane topology. Accordingly, MinE showed characteristic features of protein-induced membrane tubulation and lipid clustering in in vitro reconstituted systems. In conclusion, MinE shares common protein signatures with a group of membrane trafficking proteins in eukaryotic cells. These MinE signatures appear to affect membrane curvature. PMID:21738659

Heavy ions in space (M0001)

NASA Technical Reports Server (NTRS)

Adams, J. H., Jr.; Slberberg, R.; Tsao, C. H.

1984-01-01

The ojectives are to investigate three components of heavy nuclei in space: (1) a recently observed anomalous component of low-energy nuclei of N, O, and Ne; (2) the heavy nuclei in the Van Allen radiation belts; and (3) the UH nuclei (Z 30) of the galactic radiation. The study of the anomalous flux of N, O, and Ne nuclei in the unexplored energy region above 100 MeV/u is expected to provide new insights into the source of this component. Its observation in this experiment will confirm that these ions are singly charged. Knowledge of the energy spectra of the heavy nuclei observed in the Van Allen belts is expected to enhance the understanding of the origin of the belts (e.g., injection and local acceleration pocesses). The observation of these heavy ions could show, for the first time, that low-energy particles of extraterrestrial origin can diffuse to the innermost parts of the magnetosphere. Measurements of the UH component are expected to contribute information concerning its source, interstellar propagation, and the galactic storage time.

Challenging Cosmic Ray Propagation with Antiprotons: Evidence for a "Fresh" Nuclei Component?

NASA Technical Reports Server (NTRS)

Moskalenko, Igor V.; Strong, Andrew W.; Mashnik, Stepan G.; Ormes, Jonathan F.

2002-01-01

Recent measurements of the cosmic ray (CR) antiproton flux have been shown to challenge existing CR propagation models. It was shown that the reacceleration models designed to match secondary to primary nuclei ratio (e.g., Boron/Carbon) produce too few antiprotons, while the traditional non-reacceleration models can reproduce the antiproton flux but fall short of explaining the low-energy decrease in the secondary to primary nuclei ratio. Matching both the secondary to primary nuclei ratio and antiproton flux requires artificial breaks in the diffusion coefficient and the primary injection spectrum suggesting the need for other approaches. In the present paper we discuss one possibility to overcome these difficulties. Using the measured antiproton flux to fix the diffusion coefficient, we show that the spectra of primary nuclei as measured in the heliosphere may contain a fresh local unprocessed component at low energies, thus decreasing the measured secondary to primary nuclei ratio. A model reproducing antiprotons, B/C ratio, and abundances up to Ni is presented.

Infrared Spectroscopic Imaging for Prostate Pathology Practice

DTIC Science & Technology

2011-04-01

features – geometric properties of epithelial cells/nuclei and lumens – that are quantified based on H&E stained images as well as FT-IR images of...the samples. By restricting the features used to geometric measures, we sought to mimic the pattern recognition process employed by human experts, and...relatively dark and can be modeled as small elliptical areas in the stained images. This geometrical model is often confounded as multiple nuclei can be

Optical, Near-IR, and Sub-mm IFU Observations of the Nearby Dual Active Galactic Nuclei MRK 463

NASA Astrophysics Data System (ADS)

Treister, Ezequiel; Privon, George C.; Sartori, Lia F.; Nagar, Neil; Bauer, Franz E.; Schawinski, Kevin; Messias, Hugo; Ricci, Claudio; U, Vivian; Casey, Caitlin; Comerford, Julia M.; Muller-Sanchez, Francisco; Evans, Aaron S.; Finlez, Carolina; Koss, Michael; Sanders, David B.; Urry, C. Megan

2018-02-01

We present optical and near-IR Integral Field Unit (IFU) and ALMA band 6 observations of the nearby dual active galactic nuclei (AGNs) Mrk 463. At a distance of 210 Mpc, and a nuclear separation of ∼4 kpc, Mrk 463 is an excellent laboratory to study the gas dynamics, star formation processes and supermassive black hole (SMBH) accretion in a late-stage gas-rich major galaxy merger. The IFU observations reveal a complex morphology, including tidal tails, star-forming clumps, and emission-line regions. The optical data, which map the full extent of the merger, show evidence for a biconical outflow and material outflowing at >600 km s‑1, both associated with the Mrk 463E nucleus, along with large-scale gradients likely related to the ongoing galaxy merger. We further find an emission-line region ∼11 kpc south of Mrk 463E that is consistent with photoionization by an AGN. Compared to the current AGN luminosity, the energy budget of the cloud implies a luminosity drop in Mrk 463E by a factor of 3–20 over the last 40,000 years. The ALMA observations of 12CO(2–1) and adjacent 1 mm continuum reveal the presence of ∼109 M ⊙ in molecular gas in the system. The molecular gas shows velocity gradients of ∼800 km s‑1 and ∼400 km s‑1 around the Mrk 463E and 463W nuclei, respectively. We conclude that, in this system, the infall of ∼100s M ⊙ yr‑1 of molecular gas is in rough balance with the removal of ionized gas by a biconical outflow being fueled by a relatively small, <0.01% of accretion onto each SMBH.

Systematic analysis of hot Yb* isotopes using the energy density formalism

NASA Astrophysics Data System (ADS)

Jain, Deepika; Sharma, Manoj K.; Rajni; Kumar, Raj; Gupta, Raj K.

2014-10-01

A systematic study of the spin-orbit density interaction potential is carried out, with spherical as well as deformed choices of nuclei, for a variety of near-symmetric and asymmetric colliding nuclei leading to various isotopes of the compound nucleus Yb*, using the semiclassical extended Thomas-Fermi formulation (ETF) of the Skyrme energy density formalism (SEDF). We observe that the spin-orbit density interaction barrier height ( and barrier position ( increase systematically with the increase in number of neutrons in both the projectile and target, for spherical systems. On allowing deformation effects with optimum orientations, the barrier-height increases by a large order of magnitude, as compared to the spherical case, in going from 156Yb* to 172Yb* nuclear systems formed via near-symmetric Ni+Mo or asymmetric O+Sm colliding nuclei, except that for the oblate-shaped nuclei, the is the highest and shifts towards a smaller (compact) interaction radius. The temperature does not change the behavior of spin-orbit density dependent ( and independent ( interaction potentials, except for some minor changes in the magnitude. The orientation degree of freedom also plays an important role in modifying the barrier characteristics and hence produces a large effect on the fusion cross section. The fusion excitation function of the compound nuclei 160, 164Yb* formed in different incoming channels, show clearly that the new forces GSkI and KDE0v1 respond better than the old SIII force. Among the first two, KDE0v1 seems to perform better. The fusion cross-sections are also predicted for a few other isotopes of Yb*.

Effects of Mode of Deformation and Extent of Reduction on Evolution of {111}-Fiber During Cold Rolling of Ni-16Cr Alloy

NASA Astrophysics Data System (ADS)

Mehta, K. K.; Mandal, R. K.; Singh, A. K.

2018-07-01

The high ratio of relative resolved shear stress on a twin to planar slip system results in microstructural latent hardening (some kind of overshooting) by the twin system on the primary slip planes, which leads to development of the {111}-fiber in Ni-16Cr alloy. The development of {111}-fiber starts as early as around 16 pct cold reduction in Ni-16Cr alloy and persists with maximum average intensity ranging from 35 to 40 pct additional deformation, i.e., around 50 pct cold reduction in unidirectional (U) and two-step cross (T)-rolling modes. In between 50 and 68 pct reductions in U and T modes, the fiber becomes unstable and starts disappearing. However, in multistep cross (M) rolling, the {111}-fiber formation starts late, i.e., at around 50 pct reduction, and maintains its stability up to additional deformation ranging from 35 to 40 pct, i.e., around 90 pct cold reduction. Thus, the life of {111}-fiber remains stable only within the range from 35 to 40 pct intermediate deformation during cold rolling of Ni-16Cr alloy irrespective of modes of rolling. However, the start and end of fiber stabilities depend on the modes of deformation by rolling. The maximum average intensity of {111}-fiber that can be attained in Ni-16Cr alloy is around 3.6× random in any of the deformation modes.

Effects of Mode of Deformation and Extent of Reduction on Evolution of {111}-Fiber During Cold Rolling of Ni-16Cr Alloy

NASA Astrophysics Data System (ADS)

Mehta, K. K.; Mandal, R. K.; Singh, A. K.

2018-04-01

The high ratio of relative resolved shear stress on a twin to planar slip system results in microstructural latent hardening (some kind of overshooting) by the twin system on the primary slip planes, which leads to development of the {111}-fiber in Ni-16Cr alloy. The development of {111}-fiber starts as early as around 16 pct cold reduction in Ni-16Cr alloy and persists with maximum average intensity ranging from 35 to 40 pct additional deformation, i.e., around 50 pct cold reduction in unidirectional (U) and two-step cross (T)-rolling modes. In between 50 and 68 pct reductions in U and T modes, the fiber becomes unstable and starts disappearing. However, in multistep cross (M) rolling, the {111}-fiber formation starts late, i.e., at around 50 pct reduction, and maintains its stability up to additional deformation ranging from 35 to 40 pct, i.e., around 90 pct cold reduction. Thus, the life of {111}-fiber remains stable only within the range from 35 to 40 pct intermediate deformation during cold rolling of Ni-16Cr alloy irrespective of modes of rolling. However, the start and end of fiber stabilities depend on the modes of deformation by rolling. The maximum average intensity of {111}-fiber that can be attained in Ni-16Cr alloy is around 3.6× random in any of the deformation modes.

Ghost beams and the energy spectra of anomalous positrons

NASA Astrophysics Data System (ADS)

Fox, J. D.; Kemper, K. W.; Cottle, P. D.

1995-05-01

It is suggested that nuclear reactions induced by medium mass projectiles, with {A}/{q} close to that of the primary beam, could explain the anomalous positron-electron peaks observed in sub-barrier collisions of very heavy nuclei. The reactions result in prominent γ-rays which convert to e +e - pairs in material near the target. Possible experiments to examine this hypothesis are suggested.

Cosmic jets

NASA Technical Reports Server (NTRS)

Rees, M. J.

1986-01-01

The evidence that active galactic nuclei produce collimated plasma jets is summarised. The strongest radio galaxies are probably energised by relativistic plasma jets generated by spinning black holes interacting with magnetic fields attached to infalling matter. Such objects can produce e(+)-e(-) plasma, and may be relevant to the acceleration of the highest-energy cosmic ray primaries. Small-scale counterparts of the jet phenomenon within our own galaxy are briefly reviewed.

EMC effect for light nuclei: New results from Jefferson Lab

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aji Daniel

High energy lepton scattering has been the primary tool for mapping out the quark distributions of nucleons and nuclei. Measurements of deep inelastic scattering in nuclei show that the quark distributions in heavy nuclei are not simply the sum of the quark distributions of the constituent proton and neutron, as one might expect for a weakly bound system. This modification of the quark distributions in nuclei is known as the EMC effect. I will discuss the results from Jefferson Lab (JLab) experiment E03-103, a precise measurement of the EMC effect in few-body nuclei with emphasis on the large x region.more » Data from the light nuclei suggests that the nuclear dependence of the high x quark distribution may depend on the nucleon's local environment, rather than being a purely bulk effect. In addition, I will also discuss about a future experiment at the upgraded 12 GeV Jefferson Lab facility which will further investigate the role of the local nuclear environment and the influence of detailed nuclear structure to the modification of quark distributions.« less

LAD Prize Talk: Lab Astro and the Origins of the Chemical Elements

NASA Astrophysics Data System (ADS)

Lawler, James E.

2017-06-01

Only a few of the lightest or primordial nuclei were made just after the Big Bang. Other light nuclei up to the Fe-group are made by fusion in stars. Heavier nuclei are made primarily via r(apid)-process and s(low)-process n(eutron)-capture events. Although the s-process n-capture is fairly well understood, the r-process n-capture events remain poorly understood. The relative role of Core Collapse SNe and n-star mergers will likely be understood in the next few decades. I will discuss recent studies of old Metal-Poor stars that are revealing some new details of nucleosynthesis. This progress is due to the availability of high resolution spectra from large ground based telescopes, access to the UV via HST, and better laboratory data. Our laboratory astrophysics program has focused primarily on the measurement of transition probabilities by combining radiative lifetimes with emission branching fractions. The use of Time Resolved Laser Induced Fluorescence (TRLIF) to measure radiative lifetimes in metallic atoms and ions provides an absolute scale for transition probabilities accurate to a few percent [e.g. 1]. The development and application of TRLIF to neutral and ionized atoms of nearly all elements is due to a simple, versatile, and reliable atom/ion beam source based on a hollow cathode discharge [2, 3]. Fourier transform spectrometers (FTSs) are essential in the measurement of emission branching fractions for atoms and ions with dense spectra such as the rare earths [e.g. 4, 5]. A 3 m focal length echelle spectrometer is important to the measurement of weak branches which might otherwise be obscured by multiplex noise in FTS data [6, 7]. References: [1] E. A. Den Hartog et al., ApJS 194: 35 (2011). [2] D. W. Duquette et al., Phys. Rev. A24, 2847 (1981). [3] S. Salih & J. E. Lawler, Phys. Rev. A29, 3753, (1983). [4] J. W. Brault, J. Opt. Soc. Am. 66, 1081 (1976). [5] J. E. Lawler et al., ApJS 182, 51 (2009). [6] M. P. Wood & J. E. Lawler, Appl. Opt. 51, 8407 (2012). [7] C. Sneden et al., ApJ 817:53 (2016).

The triaxiality and Coriolis effects on the fission barrier in isovolumic nuclei with mass number A = 256 based on multidimensional total Routhian surface calculations

NASA Astrophysics Data System (ADS)

Chai, Qing-Zhen; Zhao, Wei-Juan; Wang, Hua-Lei; Liu, Min-Liang; Xu, Fu-Rong

2018-05-01

The triaxiality and Coriolis effects on the first fission barrier in even-even nuclei with A=256 have been studied in terms of the approach of multidimensional total Routhian surface calculations. The present results are compared with available data and other theories, showing a good agreement. Based on the deformation energy or Routhian curves, the first fission barriers are analyzed, focusing on their shapes, heights, and evolution with rotation. It is found that, relative to the effect on the ground-state minimum, the saddle point, at least the first one, can be strongly affected by the triaxial deformation degree of freedom and Coriolis force. The evolution trends of the macroscopic and microscopic (shell and pairing) contributions as well as the triaxial fission barriers are briefly discussed.

Pre-scission model predictions of fission fragment mass distributions for super-heavy elements

NASA Astrophysics Data System (ADS)

Carjan, N.; Ivanyuk, F. A.; Oganessian, Yu. Ts.

2017-12-01

The total deformation energy just before the moment of neck rupture for the heaviest nuclei for which spontaneous fission has been detected (Ds281279-, 281Rg and Cn284282-) is calculated. The Strutinsky's prescription is used and nuclear shapes just before scission are described in terms of Cassinian ovals defined for the fixed value of elongation parameter α = 0.98 and generalized by the inclusion of four additional shape parameters: α1, α3, α4, and α6. Supposing that the probability of each point in the deformation space is given by Boltzmann factor, the distribution of the fission-fragment masses is estimated. The octupole deformation α3 at scission is found to play a decisive role in determining the main feature of the mass distribution: symmetric or asymmetric. Only the inclusion of α3 leads to an asymmetric division. Finally, the calculations are extended to an unexplored region of super-heavy nuclei: the even-even Fl (Z = 114), Lv (Z = 116), Og (Z = 118) and (Z = 126) isotopes. For these nuclei, the most probable mass of the light fragment has an almost constant value (≈136) like in the case of the most probable mass of the heavy fragment in the actinide region. It is the neutron shell at 82 that makes this light fragment so stable. Naturally, for very neutron-deficient isotopes, the mass division becomes symmetric when N = 2 × 82.

Thouless-Valatin rotational moment of inertia from linear response theory

NASA Astrophysics Data System (ADS)

Petrík, Kristian; Kortelainen, Markus

2018-03-01

Spontaneous breaking of continuous symmetries of a nuclear many-body system results in the appearance of zero-energy restoration modes. These so-called spurious Nambu-Goldstone modes represent a special case of collective motion and are sources of important information about the Thouless-Valatin inertia. The main purpose of this work is to study the Thouless-Valatin rotational moment of inertia as extracted from the Nambu-Goldstone restoration mode that results from the zero-frequency response to the total-angular-momentum operator. We examine the role and effects of the pairing correlations on the rotational characteristics of heavy deformed nuclei in order to extend our understanding of superfluidity in general. We use the finite-amplitude method of the quasiparticle random-phase approximation on top of the Skyrme energy density functional framework with the Hartree-Fock-Bogoliubov theory. We have successfully extended this formalism and established a practical method for extracting the Thouless-Valatin rotational moment of inertia from the strength function calculated in the symmetry-restoration regime. Our results reveal the relation between the pairing correlations and the moment of inertia of axially deformed nuclei of rare-earth and actinide regions of the nuclear chart. We have also demonstrated the feasibility of the method for obtaining the moment of inertia for collective Hamiltonian models. We conclude that from the numerical and theoretical perspective, the finite-amplitude method can be widely used to effectively study rotational properties of deformed nuclei within modern density functional approaches.

Early stage fatigue damage occurs in bovine tendon fascicles in the absence of changes in mechanics at either the gross or micro-structural level

PubMed Central

Shepherd, Jennifer H.; Riley, Graham P.; Screen, Hazel R.C.

2014-01-01

Many tendon injuries are believed to result from repetitive motion or overuse, leading to the accumulation of micro-damage over time. In vitro fatigue loading can be used to characterise damage during repeated use and investigate how this may relate to the aetiology of tendinopathy. This study considered the effect of fatigue loading on fascicles from two functionally distinct bovine tendons: the digital extensor and deep digital flexor. Micro-scale extension mechanisms were investigated in fascicles before or after a period of cyclic creep loading, comparing two different measurement techniques – the displacement of a photo-bleached grid and the use of nuclei as fiducial markers. Whilst visual damage was clearly identified after only 300 cycles of creep loading, these visual changes did not affect either gross fascicle mechanics or fascicle microstructural extension mechanisms over the 900 fatigue cycles investigated. However, significantly greater fibre sliding was measured when observing grid deformation rather than the analysis of nuclei movement. Measurement of microstructural extension with both techniques was localised and this may explain the absence of change in microstructural deformation in response to fatigue loading. Alternatively, the data may demonstrate that fascicles can withstand a degree of matrix disruption with no impact on mechanics. Whilst use of a photo-bleached grid to directly measure the collagen is the best indicator of matrix deformation, nuclei tracking may provide a better measure of the strain perceived directly by the cells. PMID:25001495

Long-term deformation in the Mississippi Embayment (Central USA) imaged by high-resolution seismic reflection data

NASA Astrophysics Data System (ADS)

Hao, Yanjun

Large magnitude intraplate earthquakes are a puzzling exception to plate tectonic theory. Unlike earthquakes occurring along plate boundaries, large continental intraplate earthquakes are a rare occurrence and are often distributed over broad regions. Albeit rare, their occurrence can cause widespread damage because of the low attenuation of seismic energy typical of plate interiors [Hanks and Johnston, 1992]. In the Central USA, most of the recent tectonic intraplate seismicity concentrates along the New Madrid seismic zone (NMSZ), where three large (M>7) earthquakes occurred between 1811--1812 [Johnston and Schweig, 1996]. Here the low surface deformation rates [Calais and Stein, 2009] conflict with the elevated instrument-recorded seismicity and the occurrence of historical and prehistorical large magnitude events [Tuttle et al., 2002]. One of the promising hypotheses proposed to reconcile this apparent contradiction is that intraplate earthquakes may be temporally clustered, episodic or cyclic, and may migrate spatially at the regional or continental scale across multiple faults or fault systems. In order to test this hypothesis and to understand how and where the long-term deformation is accommodated in the Mississippi Embayment, Central USA, I utilize high-resolution seismic reflection data acquired by the Mississippi River Project [Magnani and McIntosh, 2009] and by a 2010 survey across the Meeman-Shelby fault [Magnani, 2011; Hao et al., 2013]. To identify the location of Quaternary deformation and characterize deformation history, I acquired, processed, and interpreted the seismic reflection data and integrated them with other available geophysical (e.g. seismicity, crustal and lithospheric models) and geological (e.g. magmatism and borehole) data. For my research, I focus on three regions in the Mississippi Embayment: 1) the Meeman-Shelby fault west of Memphis, Tennessee, 2) the eastern Reelfoot rift margin north of Memphis, Tennessee, and 3) the area in southeastern Arkansas along the Alabama-Oklahoma transform zone. Quaternary deformation and prolonged history of activity of the imaged faults is documented at all sites. The results show that Quaternary seismic activity in the Mississippi Embayment is accommodated by faults additional to the NMSZ fault system, and that fault activity is controlled by certain paleotectonic structures inherited from the Proterozoic and Paleozoic history of the North American continent. The identification of Quaternary seismogenic faults outside the footprint of the NMSZ and of the lower crustal anomaly (i.e. "rift pillow") supports seismotectonic models that predict deformation over a large area (e.g. Forte et al., 2007) and calls into questions in models that predict concentration of strain in the NMSZ region (e.g. Pollitz et al., 2001). A comparison between the newly imaged faults and the NMSZ faults shows that the former are indistinguishable from the latter except for the occurrence of instrumental seismicity. Based on the analysis of the location and sense of displacement of Quaternary deformation in the northern Mississippi Embayment, I propose a new fault network to reconcile the wide distribution of Quaternary faults with concentration of instrumental seismicity along the NMSZ. The fault network consists of three distinct trends of faults: ~N45°E right-lateral strike-slip faults, ~N20°W reverse faults, and ~N25°E right-lateral strike-slip faults. Different faults in the fault network appear to have been active at different times across the northern embayment. The available age data suggest a northward migration of the deformation, with the NMSZ representing the latest and youngest fault system.

Deformation rate-, hold time-, and cycle-dependent shape-memory performance of Veriflex-E resin

NASA Astrophysics Data System (ADS)

McClung, Amber J. W.; Tandon, Gyaneshwar P.; Baur, Jeffery W.

2013-02-01

Shape-memory polymers have attracted great interest in recent years for application in reconfigurable structures (for instance morphing aircraft, micro air vehicles, and deployable space structures). However, before such applications can be attempted, the mechanical behavior of the shape-memory polymers must be thoroughly understood. The present study represents an assessment of viscous effects during multiple shape-memory cycles of Veriflex-E, an epoxy-based, thermally triggered shape-memory polymer resin. The experimental program is designed to explore the influence of multiple thermomechanical cycles on the shape-memory performance of Veriflex-E. The effects of the deformation rate and hold times at elevated temperature on the shape-memory behavior are also investigated.

Finite Deformations and Internal Forces in Elastic-Plastic Crystals: Interpretations From Nonlinear Elasticity and Anharmonic Lattice Statics

DTIC Science & Technology

2009-09-01

Sec. 2, while the latter ase—which implicitly includes the effects of image forces of efects in neighboring volume elements—may be more practical rom...versetzungen und eigenspannungen,” Arch . Ration. Mech. Anal., 4, pp. 273–334. 25 Lee, E. H., 1969, “Elastic-Plastic Deformation at Finite Strains,” ASME J...Rev., 73, pp. 373–382. 27 Kroner, E., and Seeger, A., 1959, “Nicht-Lineare Elastizitatstheorie der Verset- zungen und Eigenspannungen,” Arch . Ration

Role of higher-multipole deformations in exotic {sup 14}C cluster radioactivity

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

2011-06-15

We have studied nine cases of spontaneous emission of {sup 14}C clusters in the ground-state decays of the same number of parent nuclei from the trans-lead region, specifically from {sup 221}Fr to {sup 226}Th, using the preformed cluster model (PCM) of Gupta and collaborators, with choices of spherical, quadrupole deformation ({beta}{sub 2}) alone, and higher-multipole deformations ({beta}{sub 2}, {beta}{sub 3}, {beta}{sub 4}) with cold ''compact'' orientations {theta}{sup c} of decay products. The calculated {sup 14}C cluster decay half-life times are found to be in nice agreement with experimental data only for the case of higher-multipole deformations ({beta}{sub 2}-{beta}{sub 4}) andmore » {theta}{sup c} orientations of cold elongated configurations. In other words, compared to our earlier study of clusters heavier than {sup 14}C, where the inclusion of {beta}{sub 2} alone, with ''optimum'' orientations, was found to be enough to give the best comparison with data, here for {sup 14}C cluster decay the inclusion of higher-multipole deformations (up to hexadecapole), together with {theta}{sup c} orientations, is found to be essential on the basis of the PCM. Interestingly, whereas both the penetration probability and assault frequency work simply as scaling factors, the preformation probability is strongly influenced by the order of multipole deformations and orientations of nuclei. The possible role of Q value and angular-momentum effects are also considered in reference to {sup 14}C cluster radioactivity.« less

The Cosmic-Ray Proton and Helium Spectra between 0.4 and 200 GV

NASA Astrophysics Data System (ADS)

Boezio, M.; Carlson, P.; Francke, T.; Weber, N.; Suffert, M.; Hof, M.; Menn, W.; Simon, M.; Stephens, S. A.; Bellotti, R.; Cafagna, F.; Castellano, M.; Circella, M.; De Marzo, C.; Finetti, N.; Papini, P.; Piccardi, S.; Spillantini, P.; Ricci, M.; Casolino, M.; De Pascale, M. P.; Morselli, A.; Picozza, P.; Sparvoli, R.; Barbiellini, G.; Bravar, U.; Schiavon, P.; Vacchi, A.; Zampa, N.; Mitchell, J. W.; Ormes, J. F.; Streitmatter, R. E.; Golden, R. L.; Stochaj, S. J.

1999-06-01

We report on the hydrogen nuclei (protons and deuterons) spectrum from 0.15 to 200 GeV and on the helium nuclei spectrum over the energy range from 0.2 to 100 GeV nucleon-1 at the top of the atmosphere measured by the balloon-borne experiment Cosmic Antiparticle Ring-Imaging Cerenkov Experiment (CAPRICE), which was flown from Lynn Lake, Manitoba, Canada, on 1994 August 8-9. We also report on the proton spectrum over the energy range from 0.15 to 4.2 GeV. The experiment used the NMSU-WiZard/CAPRICE balloon-borne magnet spectrometer equipped with a solid radiator Ring-Imaging Cerenkov (RICH) detector and a silicon-tungsten calorimeter for particle identification. This was the first time a RICH was used together with an imaging calorimeter in a balloon-borne experiment. These detectors allowed for clear particle identification, as well as excellent control of the detector efficiencies. The data were collected during 18 hr at a residual mean atmospheric depth of 3.9 g cm-2. With this apparatus 516,463 hydrogen and 32,457 helium nuclei were identified in the rigidity range 0.4 to 200 GV and 1.2 to 200 GV, respectively. The observed energy spectrum at the top of the atmosphere can be represented by (1.1+/-0.1)×104 E-2.73+/-0.06 particles (m2 GeV sr s)-1 for hydrogen (E in GeV) between 20 and 200 GeV and (4.3+/-0.9)×102 E-2.65+/-0.07 particles (m2 GeV nucleon-1 sr s)-1 for helium nuclei (E in GeV nucleon-1) between 10 and 100 GeV nucleon-1. These spectra are in good agreement with other recent measurements above 10 GeV. The observed spectra flatten below 10 GeV due to solar modulation and are consistent with earlier measurements when solar modulation is taken into account. Between 5 and 200 GV the hydrogen to helium ratio as a function of rigidity was found to be approximately constant at 6.1+/-0.1.

The Heavy Nuclei eXplorer (HNX) Mission

NASA Technical Reports Server (NTRS)

Binns, W. R.; Adams, J. H.; Barbier, L. M.; Craig, N.; Cummings, A. C.; Cummings, J. R.; Doke, T.; Hasebe, N.; Hayashi, T.; Whitaker, Ann F. (Technical Monitor)

2001-01-01

The primary scientific objectives of HNX, which was recently selected by NASA for a Small Explorer (SMEX) Mission Concept Study, are to measure the age of the galactic cosmic rays (GCR) since nucleosynthesis, determine the injection mechanism for the GCR accelerator (Volatility or FIP), and study the mix of nucleosynthetic processes that contribute to the source of GCRs. The experimental goal of HNX is to measure the elemental abundances of all individual stable nuclei from neon through the actinides and possibly beyond. HNX is composed of two instruments: ECCO, which measures elemental abundances of nuclei with Z greater than or equal to 72, and ENTICE. which measures elemental abundances of nuclei with Z between 10 and 82. We describe the mission and the science that can be addressed by HNX.

Photonuclear interactions of ultrahigh energy cosmic rays and their astrophysical consequences

NASA Technical Reports Server (NTRS)

Puget, J. L.; Stecker, F. W.; Bredekamp, J. H.

1975-01-01

Results of detailed Monte Carlo calculations of the interaction histories of ultrahigh energy cosmic-ray nuclei with intergalactic radiation fields are presented. Estimates of these fields and empirical determinations of photonuclear cross sections are used, including multinuclear disintegrations for nuclei up to 56Fe. Intergalactic and galactic energy loss rates and nucleon loss rates for nuclei up to 56Fe are also given. Astrophysical implications are discussed in terms of expected features in the cosmic-ray spectrum between quintillion and sextillion eV for the universal and supercluster origin hypotheses. The results of these calculations indicate that ultrahigh energy cosmic rays cannot be universal in origin regardless of whether they are protons or nuclei. Both the supercluster and galactic origin hypotheses, however, are possible regardless of nuclear composition.

Understanding the Effect of Grain Boundary Character on Dynamic Recrystallization in Stainless Steel 316L

NASA Astrophysics Data System (ADS)

Beck, Megan; Morse, Michael; Corolewski, Caleb; Fritchman, Koyuki; Stifter, Chris; Poole, Callum; Hurley, Michael; Frary, Megan

2017-08-01

Dynamic recrystallization (DRX) occurs during high-temperature deformation in metals and alloys with low to medium stacking fault energies. Previous simulations and experimental research have shown the effect of temperature and grain size on DRX behavior, but not the effect of the grain boundary character distribution. To investigate the effects of the distribution of grain boundary types, experimental testing was performed on stainless steel 316L specimens with different initial special boundary fractions (SBF). This work was completed in conjunction with computer simulations that used a modified Monte Carlo method which allowed for the addition of anisotropic grain boundary energies using orientation data from electron backscatter diffraction (EBSD). The correlation of the experimental and simulation work allows for a better understanding of how the input parameters in the simulations correspond to what occurs experimentally. Results from both simulations and experiments showed that a higher fraction of so-called "special" boundaries ( e.g., Σ3 twin boundaries) delayed the onset of recrystallization to larger strains and that it is energetically favorable for nuclei to form on triple junctions without these so-called "special" boundaries.

Asymmetric Magnetosphere Deformation Driven by Hot Flow Anomaly(ies)

NASA Technical Reports Server (NTRS)

Safrankova, J.; Goncharov, O.; Nemecek, Z.; Prech, L.; Sibeck, D. G.

2012-01-01

We present a case study of a large deformation of the magnetopause on November 26, 2008. The investigation is based on observations of five THEMIS spacecraft located at the dawn flank in the magnetosphere and magnetosheath, on Cluster measurements at the dusk magnetosheath, and is supported by ACE solar wind monitoring. The main revelation of our study is that the interaction of the IMF discontinuity with the bow shock creates either one very elongated hot flow anomaly (HFA) or a pair of them that is (are) simultaneously observed at both flanks. Whereas the dusk HFA is weak and does not cause observable deformation of the magnetopause, the pressure variations connected with the dawn HFA lead to a magnetopause displacement by approx. = 5 R(sub E) outward from its nominal position. This is followed by a rapid inward motion of the magnetopause approx. = 4 R(sub E) inward with respect to the model location. The surface deformation is so large that the outermost THEMIS spacecraft was in the magnetosphere, whereas the spacecraft located 9 R(sub E) inbound entered into the magnetosheath at the same time. The whole event lasted about 5 minutes.

Strength evolution of simulated carbonate-bearing faults: The role of normal stress and slip velocity

NASA Astrophysics Data System (ADS)

Mercuri, Marco; Scuderi, Marco Maria; Tesei, Telemaco; Carminati, Eugenio; Collettini, Cristiano

2018-04-01

A great number of earthquakes occur within thick carbonate sequences in the shallow crust. At the same time, carbonate fault rocks exhumed from a depth < 6 km (i.e., from seismogenic depths) exhibit the coexistence of structures related to brittle (i.e., cataclasis) and ductile deformation processes (i.e., pressure-solution and granular plasticity). We performed friction experiments on water-saturated simulated carbonate-bearing faults for a wide range of normal stresses (from 5 to 120 MPa) and slip velocities (from 0.3 to 100 μm/s). At high normal stresses (σn > 20 MPa) fault gouges undergo strain-weakening, that is more pronounced at slow slip velocities, and causes a significant reduction of frictional strength, from μ = 0.7 to μ = 0.47. Microstructural analysis show that fault gouge weakening is driven by deformation accommodated by cataclasis and pressure-insensitive deformation processes (pressure solution and granular plasticity) that become more efficient at slow slip velocity. The reduction in frictional strength caused by strain weakening behaviour promoted by the activation of pressure-insensitive deformation might play a significant role in carbonate-bearing faults mechanics.

miR-195 inhibited abnormal activation of osteoblast differentiation in MC3T3-E1 cells via targeting RAF-1.

PubMed

Chao, Chen; Li, Feng; Tan, Zhiping; Zhang, Weizhi; Yang, Yifeng; Luo, Cheng

2018-01-15

Recent reports have demonstrated that RAF-1 L613V (a mutant of RAF-1) mutant mice show bone deformities similar to Noonan syndrome. It has been suggested that RAF-1 L613V might abnormally activate osteoblast differentiation of MC3T3-E1 cells. To demonstrate that RAF-1 is associated with bone deformity and that RAF-1 L613V dependent bone deformity could be inhibited by microRNA-195 (miR-195), we first investigated the amplifying influence of wild-type RAF-1 (WT) or RAF-1 L613V (L613V) on the viability and differentiation of MC3T3-E1 cells induced by bone morphogenetic protein-2 (BMP-2) via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, alkaline phosphatase (ALP) and Alizarin Red S (ARS) staining, quantitative real-time polymerase chain reaction (qRT-PCR) and western blot analysis. Subsequently, we investigated the blocking effect and its mechanism of miR-195 for abnormal activation of osteoblast differentiation of MC3T3-E1 cells via targeting RAF-1. RAF-1, especially RAF-1 L613V , abnormally activates osteoblast differentiation of MC3T3-E1 cells induced by BMP-2. Meanwhile, miR-195 could inhibit the cell viability and differentiation of MC3T3-E1 cells. Transfection of miR-195 largely suppressed the L613V-induced viability and osteoblast differentiation of MC3T3-E1 cells and attenuated the accelerative effect of L613V on runt-related transcription factor-2 (Runx2), Osterix (OSX), alkaline phosphatase (ALP), osteocalcin (OCN), and distal-less homeobox 5 (DLX5) osteogenic gene expressions. In addition, miR-195 decreased the expression of RAF-1 mRNA and protein by directly targeting the 3'-untranslated regions (3'-UTR) of RAF-1 mRNA in MC3T3-E1 cells. Our findings indicated that miR-195 inhibited WT and L613V RAF-1 induced hyperactive osteoblast differentiation in MC3T3-E1 cells by targeting RAF-1. miR-195 might be a novel therapeutic agent for the treatment of L613V-induced bone deformity in Noonan syndrome. Copyright © 2017. Published by Elsevier Inc.

Automated Segmentation of Nuclei in Breast Cancer Histopathology Images.

PubMed

Paramanandam, Maqlin; O'Byrne, Michael; Ghosh, Bidisha; Mammen, Joy John; Manipadam, Marie Therese; Thamburaj, Robinson; Pakrashi, Vikram

2016-01-01

The process of Nuclei detection in high-grade breast cancer images is quite challenging in the case of image processing techniques due to certain heterogeneous characteristics of cancer nuclei such as enlarged and irregularly shaped nuclei, highly coarse chromatin marginalized to the nuclei periphery and visible nucleoli. Recent reviews state that existing techniques show appreciable segmentation accuracy on breast histopathology images whose nuclei are dispersed and regular in texture and shape; however, typical cancer nuclei are often clustered and have irregular texture and shape properties. This paper proposes a novel segmentation algorithm for detecting individual nuclei from Hematoxylin and Eosin (H&E) stained breast histopathology images. This detection framework estimates a nuclei saliency map using tensor voting followed by boundary extraction of the nuclei on the saliency map using a Loopy Back Propagation (LBP) algorithm on a Markov Random Field (MRF). The method was tested on both whole-slide images and frames of breast cancer histopathology images. Experimental results demonstrate high segmentation performance with efficient precision, recall and dice-coefficient rates, upon testing high-grade breast cancer images containing several thousand nuclei. In addition to the optimal performance on the highly complex images presented in this paper, this method also gave appreciable results in comparison with two recently published methods-Wienert et al. (2012) and Veta et al. (2013), which were tested using their own datasets.

Automated Segmentation of Nuclei in Breast Cancer Histopathology Images

PubMed Central

Paramanandam, Maqlin; O’Byrne, Michael; Ghosh, Bidisha; Mammen, Joy John; Manipadam, Marie Therese; Thamburaj, Robinson; Pakrashi, Vikram

2016-01-01

The process of Nuclei detection in high-grade breast cancer images is quite challenging in the case of image processing techniques due to certain heterogeneous characteristics of cancer nuclei such as enlarged and irregularly shaped nuclei, highly coarse chromatin marginalized to the nuclei periphery and visible nucleoli. Recent reviews state that existing techniques show appreciable segmentation accuracy on breast histopathology images whose nuclei are dispersed and regular in texture and shape; however, typical cancer nuclei are often clustered and have irregular texture and shape properties. This paper proposes a novel segmentation algorithm for detecting individual nuclei from Hematoxylin and Eosin (H&E) stained breast histopathology images. This detection framework estimates a nuclei saliency map using tensor voting followed by boundary extraction of the nuclei on the saliency map using a Loopy Back Propagation (LBP) algorithm on a Markov Random Field (MRF). The method was tested on both whole-slide images and frames of breast cancer histopathology images. Experimental results demonstrate high segmentation performance with efficient precision, recall and dice-coefficient rates, upon testing high-grade breast cancer images containing several thousand nuclei. In addition to the optimal performance on the highly complex images presented in this paper, this method also gave appreciable results in comparison with two recently published methods—Wienert et al. (2012) and Veta et al. (2013), which were tested using their own datasets. PMID:27649496

Uptake and metabolism of (/sup 3/H)testosterone in the brain, pituitary gland and genital tract of the male cynomolgus monkey

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bonsall, R.W.; Rees, H.D.; Micheal, R.P.

1986-03-01

To study the mechanism by which testosterone restores the sexual potency of castrated cynomolgus monkeys, two males (body weights 5.2 and 5.3 kg) were castrated and, 3 days later, injected with 3 mCi (/sup 3/H)testosterone ((/sup 3/H)T) as an intravenous bolus. After 30 min, males were killed and brains and samples of other tissues were rapidly removed and placed on ice. Samples were dissected from the right halves of the brain and homogenized. Purified cell nuclei were prepared and ether extracts were analyzed by reverse-phase HPCL. Generally, unchanged (/sup 3/H)T was the major form of radioactivity in brain and pituitarymore » gland, but in cell nuclei from hypothalamus, preoptic area and amygdala, a large proportion (34 - 61%) was in the form of (/sup 3/H)estradiol ((/sup 4/H)E/sub 2/). Little or no (/sup 3/H)dihydrotestosterone ((/sup 3/H)DHT) was detected in cell nuclei from any brain region or from pituitary gland. However, (/sup 3/H)DHT was the major form (61 - 95%) of radioactivity in cell nuclei from glans penis, prostrate and seminal vesicles. In autoradiograms of the left halves of the same brains, the percentage of cells that accumulated radioactivity in their nuclei was high in specific regions of the hypothalamus, preoptic areas and amygdala. The authors conclude that the peripheral actions of T are mediated via DHT, but its central actions are dependent on unchanged T or on E/sub 2/ formed locally by aromatization.« less

Liquid Between Macromolecules in Protein Crystals: Static Versus Dynamics

NASA Technical Reports Server (NTRS)

Chernov, A. A.

2005-01-01

Protein crystals are so fragile that they often can not be handled by tweezers. Indeed, measurements of the Young modulus, E, of lysozyme crystals resulted in E approx. equals 0.1 - 1 GPa, the lower figures, 0.1 - 0.5 GPa, being obtained from triple point bending of as-grown and not cross-linked crystals sitting in solution. The bending strength was found to be approx.10(exp -2) E. On the other hand, ultrasound speed and Mandelstam-Raman-Brilloin light scattering experiments led to much higher figures, E approx. equals 2.7 GPa. The lower figures for E were found from static or low frequency crystal deformations measurements, while the higher moduli are based on high frequency lattice vibrations, 10(exp 7) - 10(exp 10) 1/s. The physical reason for the about an order of magnitude discrepancy is in different behavior of water filling space between protein molecules. At slow lattice deformation, the not-bound intermolecular water has enough time to flow from the compressed to expanded regions of the deformed crystal. At high deformation frequencies in the ultra- and hypersound waves, the water is confined in the intermolecular space and, on that scale, behaves like a solid, thus contributing to the elastic crystal moduli. In this case, the reciprocal crystal modulus is expected to be an average of the water protein and water compressibilities (reciprocal compressibilities): the bulk modulus for lysozyme is 26 GPa, for water it is 7 GPa. Anisotropy of the crystal moduli comes from intermolecular contacts within the lattice while the high frequency hardness comes from the bulk of protein molecules and water bulk moduli. These conclusions are based on the analysis of liquid flow in porous medium to be presented.

Lorentz symmetry violation and UHECR experiments

NASA Astrophysics Data System (ADS)

Gonzalez-Mestres, L.

2001-08-01

Lorentz symmetry violation (LSV) at Planck scale can be tested through ultra-high energy cosmic rays (UHECR). We discuss deformed Lorentz symmetry (DLS) and energy non-conservation (ENC) patterns where the effective LSV parameter varies like the square of the momentum scale (e.g. quadratically de-formed relativistic kinematics, QDRK). In such patterns, a ≈ 106 LSV at Planck scale would be enough to produce observable effects on the properties of cosmic rays at the ≈ 1020 eV scale: absence of GZK cutoff, stability of unstable particles, lower interaction rates, kinematical failure of any parton model and of standard formulae for Lorentz contraction and time dilation... Its phenomeno-logical implications are compatible with existing data. Precise signatures are discussed in several patterns. If the effective LSV or ENC parameter is taken to vary linearly with the momentum scale (e.g. linearly deformed relativistic kinematics, LDRK), contradictions seem to arise with UHECR data. Conse-quences are important for UHECR and high-energy gamma-ray exper iments, as well as for high-energy cosmic rays and gravitational waves.

Strain rate sensitivity of a TRIP-assisted dual-phase high-entropy alloy

NASA Astrophysics Data System (ADS)

Basu, Silva; Li, Zhiming; Pradeep, K. G.; Raabe, Dierk

2018-05-01

Dual-phase high-entropy alloys (DP-HEAs) with transformation induced plasticity (TRIP) have an excellent strength-ductility combination. To reveal their strain-rate sensitivity and hence further understand the corresponding deformation mechanisms, we investigated the tensile behavior and microstructural evolution of a typical TRIP-DP-HEA (Fe50Mn30Co10Cr10, at. %) under different strain rates (i.e., 5 × 10-3 s-1, 1 × 10-3 s-1, 5 × 10-4 s-1 and 1 × 10-4 s-1) at room temperature. The strain rate range was confined to this regime in order to apply the digital image correlation technique for probing the local strain evolution during tensile deformation at high resolution and to correlate it to the microstructure evolution. Grain size effects of the face-centered cubic (FCC) matrix and the volume fractions of the hexagonal-close packed (HCP) phase prior to deformation were also considered. The results show that within the explored strain rate regime the TRIP-DP-HEA has a fairly low strain rate sensitivity parameter within the range from 0.004 to 0.04, which is significantly lower than that of DP and TRIP steels. Samples with varying grain sizes (e.g., 2.8 μm and 38 μm) and starting HCP phase fractions (e.g., 25% and 72%) at different strain rates show similar deformation mechanisms, i.e., dislocation plasticity and strain-induced transformation from the FCC matrix to the HCP phase. The low strain rate sensitivity is attributed to the observed dominant displacive transformation mechanism. Also, the coarse-grained alloy samples with a very high starting HCP phase fraction ( 72%) prior to deformation show very good ductility with a total elongation of 60%, suggesting that both, the initial and the transformed HCP phase in the TRIP-DP-HEA are ductile and deform further via dislocation slip at the different strain rates which were probed.

Monte Carlo simulations of electron lateral distributions in the core region of 10(13) - 10(16) eV air showers

NASA Technical Reports Server (NTRS)

Ash, A. G.

1985-01-01

This paper contains details of computer models of shower development which have been used to investigate the experimental data on shower cores observed in the Leeds 35 sq m and Sacramento Peak (New Mexico) 20 sq m arrays of current limited spark (discharge) chambers. The simulations include predictions for primaries ranging from protons to iron nuclei (with heavy nuclei treated using both superposition and fragmentation models).

Deep inelastic scattering of leptons from nuclear targets and the BFKL Pomeron

NASA Astrophysics Data System (ADS)

Bialas, Andrzej; Czyz, Wieslaw; Florkowski, Wojciech

1997-06-01

We calculate shadowing in the process of deep inelastic interactions of leptons with nuclei in the perturbative regime of QCD. We find appreciable shadowing for heavy nuclei (e.g., Pb) in the region of a small Bjorken scaling variable 10-5<=x<=10-3. This shadowing depends weakly on Q2, but it may be strongly influenced, especially at x>=10-3, by the existence of real parts of the forward scattering amplitudes.

Large scale shell model study of nuclear spectroscopy in nuclei around 132Sn

NASA Astrophysics Data System (ADS)

Lo Iudice, N.; Bianco, D.; Andreozzi, F.; Porrino, A.; Knapp, F.

2012-10-01

The properties of low-lying 2+ states in chains of nuclei in the proximity of the magic number N=82 are investigated within a new shell model approach exploiting an iterative algorithm alternative to Lanczos. The calculation yields levels and transition strengths in overall good agreement with experiments. The comparative analysis of the E2 and M1 transitions supports, in many cases, the scheme provided by the interacting boson model.

Capabilities of the LDEF-2 heavy nuclei collection

NASA Technical Reports Server (NTRS)

Drach, J.; Price, P. B.; Salamon, M. H.; Tarle, G.; Ahlen, S. P.

1985-01-01

To take the next big step beyond High Energy Astronomy Observatory (HEAO-3) the Heavy Nuclei Collector (HNC), to be carried on an LDEF reflight, has the goals of greatly increased collecting power ( 30 actinides) and charge resolution sigma sub Z or = 0.25 E for Z up to approximately 100, which will provide abundances of all the charges 40 or Z or = 96 and permit sensitive searches for hypothetical particles such as monopoles, superheavy elements, and quark nuggets.

Iberia versus Europe - Effects of continental break-up and round-up on hydrocarbon habitat

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bourrouilh, R.; Zolnai, G.

1988-08-01

Based on the continuity of foldbelts and the positions of intermountain continental nuclei and transcontinental megashears, a close Pangea fit is proposed for the central and north Atlantic borderlands. The Variscan arch segment missing between Brittany and Galicia in the Gulf of Gascony (Biscaye) can tentatively be identified with the Flemish Cap block off Newfoundland. At the same time the northwest African-Gondwana border (central Morocco) was located some 800 km farther to the west-northwest, as compared to its present position in southwestern Europe (Iberia). During the opening of the central and northern segments of the Atlantic Ocean (Jurassic and Cretaceous)more » and during the closure of the western Mediterranean basin, i.e., the thrust of Africa toward southern Europe (Tertiary), the European continental mass underwent deformation in the transtensive and transpressive modes, which reactivated parts of its inherited structural network. The trailing south European continental margin was partially dismembered into loosely bound continental blocks, to be assembled again during the subsequent Alpine orogenic cycle. These events can be compared with processes known in the northernmost and western segments of the North American continent. Mechanisms are proposed for the formation and deformation of inter- and intraplate basins by way of moderate shifts (wrenching) and slight rotations, the direction of which changed during the Mesozoic-Tertiary according to the global stress field. The above evolution and mechanisms had multiple and decisive effects on hydrocarbon generation, habitat, and accumulation.« less

Left ventricular myocardial velocities and deformation indexes in top-level athletes.

PubMed

D'Andrea, Antonello; Cocchia, Rosangela; Riegler, Lucia; Scarafile, Raffaella; Salerno, Gemma; Gravino, Rita; Golia, Enrica; Pezzullo, Enrica; Citro, Rodolfo; Limongelli, Giuseppe; Pacileo, Giuseppe; Cuomo, Sergio; Caso, Pio; Russo, Maria Giovanna; Bossone, Eduardo; Calabrò, Raffaele

2010-12-01

The aim of this study was to define the range of left ventricular (LV) velocities and deformation indexes in highly trained athletes, analyzing potential differences induced by different long-term training protocols. Standard echocardiography, pulsed-wave tissue Doppler echocardiography, and two-dimensional strain echocardiography of the interventricular septum and lateral wall were performed in 370 endurance athletes and 280 power athletes. Using pulsed-wave tissue Doppler, the following parameters of myocardial function were assessed: systolic peak velocities (S(m)), early (E(m)) and late (A(m)) diastolic velocities, and the E(m)/A(m) ratio. By two-dimensional strain echocardiography, peaks of regional systolic strain and LV global longitudinal strain were calculated. LV mass index and ejection fraction did not significantly differ between the two groups. However, power athletes showed an increased sum of wall thicknesses (P < .01) and relative wall thickness, while LV stroke volume and LV end-diastolic diameter (P < .001) were greater in endurance athletes. By pulsed-wave tissue Doppler analysis, E(m) and E(m)/A(m) at both the septal and lateral wall levels were higher in endurance athletes. By two-dimensional strain echocardiography, myocardial deformation indexes were comparable between the two groups. E(m)/A(m) ratios ≥ 1 were found in the overall population, while 90 % of athletes had an E(m) ≥ 16 cm/sec, S(m) ≥ 10 cm/sec, and global longitudinal strain ≤ -16%. Multivariate analyses evidenced independent positive association between Em peak velocity and LV end-diastolic volume (P < .001) and an independent correlation of global longitudinal strain with the sum of LV wall thicknesses (P < .005). This study describes the full spectrum of systolic and diastolic myocardial velocities and deformation indexes in a large population of competitive athletes. Copyright © 2010 American Society of Echocardiography. Published by Mosby, Inc. All rights reserved.

Low-Spin States From Decay Studies in the Mass 80 Region

PubMed Central

Döring, J.; Aprahamian, A.; Wiescher, M.

2000-01-01

Neutron-deficient nuclei in the mass 80 region are known to exhibit strongly deformed ground states deduced mainly from yrast-state properties measured in-beam via heavy-ion fusion-evaporation reactions. Vibrational excitations and non-yrast states as well as their interplay with the observed rotational collectivity have been less studied to date within this mass region. Thus, several β-decay experiments have been performed to populate low-spin states in the neutron-deficient 80,84Y and 80,84Sr nuclei. An overview of excited 0+ states in Sr and Kr nuclei is given and conclusions about shape evolution at low-spins are presented. In general, the non-yrast states in even-even Sr nuclei show mainly vibration-like collectivity which evolves to rotational behavior with increasing spin and decreasing neutron number. PMID:27551586

Geometrically Nonlinear Transient Analysis of Laminated Composite Plates.

DTIC Science & Technology

1982-03-01

theory (CPT), in which normals to the midsurface before deformation are assumed to remain straight and normal to the midsurface after deformation (i.e...the plate are negligible when compared to the inplane stresses, and normals to the plate midsurface before deformation remain straight but not...necessarily normal to the midsurface after deformation. $ Equations of motion The plate under consideration is composed of a finite number of orthotropic

Axons take a dive

PubMed Central

Tong, Cheuk Ka; Cebrián-Silla, Arantxa; Paredes, Mercedes F; Huang, Eric J; García-Verdugo, Jose Manuel; Alvarez-Buylla, Arturo

2015-01-01

In the walls of the lateral ventricles of the adult mammalian brain, neural stem cells (NSCs) and ependymal (E1) cells share the apical surface of the ventricular–subventricular zone (V–SVZ). In a recent article, we show that supraependymal serotonergic (5HT) axons originating from the raphe nuclei in mice form an extensive plexus on the walls of the lateral ventricles where they contact E1 cells and NSCs. Here we further characterize the contacts between 5HT supraependymal axons and E1 cells in mice, and show that suprependymal axons tightly associated to E1 cells are also present in the walls of the human lateral ventricles. These observations raise interesting questions about the function of supraependymal axons in the regulation of E1 cells. PMID:26413556

Nonrotational states in isotonic chains of heavy nuclei

NASA Astrophysics Data System (ADS)

Adamian, G. G.; Malov, L. A.; Antonenko, N. V.; Jolos, R. V.

2018-03-01

The ground-state deformations of heavy nuclei are explored with the microscopic-macroscopic approach using the single-particle Woods-Saxon potential of the quasiparticle-phonon model. The calculations of the energies of low-lying nonrotational states take into account the residual pairing and phonon-quasiparticle interactions. The spectra of these states are presented for the N =147 -161 isotones. The sensitivity of the calculated results to the parameters of the model is studied. A rather good description of the available experimental data is demonstrated.

Nonthermal electron-positron pairs and cold matter in the central engines of active galactic nuclei

NASA Technical Reports Server (NTRS)

Zdziarski, Andrzej A.

1992-01-01

The nonthermal e(+/-) pair model of the central engine of active galactic nuclei (AGNs) is discussed. The model assumes that nonthermal e(+/-) pairs are accelerated to highly relativistic energies in a compact region close to the central black hole and in the vicinity of some cold matter. The model has a small number of free parameters and explains a large body of AGN observations from EUV to soft gamma-rays. In particular, the model explains the existence of the UV bump, the soft X-rays excess, the canonical hard X-ray power law, the spectral hardening above about 10 keV, and some of the variability patterns in the soft and hard X-rays. In addition, the model explains the spectral steepening above about 50 keV seen in NGC 4151.

Vector Meson Photoproduction on Nuclei

NASA Astrophysics Data System (ADS)

Djalali, Chaden

2011-10-01

Chiral symmetry, which is spontaneously broken in vacuum, is predicted to be partially restored in ordinary nuclear matter. The properties of vector mesons, such as their masses and/or widths are expected to change in the medium. The photoproduction reaction off nuclei is a very clean way of producing the ρ, ω and φ mesons, and detect them via their hadronic or leptonic decays. The leptonic decay to e+e- has a small branching ratio but has the advantage of being free from final state interactions. One critical aspect in all these experiments is the correct determination of the shape and magnitude of the combinatorial background. The in-medium mass distributions and yields are compared to those measured in vacuum. No significant shift is observed in the masses of the mesons, however substantial increase in their widths is reported.

Estimation of M 1 scissors mode strength for deformed nuclei in the medium- to heavy-mass region by statistical Hauser-Feshbach model calculations

NASA Astrophysics Data System (ADS)

Mumpower, M. R.; Kawano, T.; Ullmann, J. L.; Krtička, M.; Sprouse, T. M.

2017-08-01

Radiative neutron capture is an important nuclear reaction whose accurate description is needed for many applications ranging from nuclear technology to nuclear astrophysics. The description of such a process relies on the Hauser-Feshbach theory which requires the nuclear optical potential, level density, and γ -strength function as model inputs. It has recently been suggested that the M 1 scissors mode may explain discrepancies between theoretical calculations and evaluated data. We explore statistical model calculations with the strength of the M 1 scissors mode estimated to be dependent on the nuclear deformation of the compound system. We show that the form of the M 1 scissors mode improves the theoretical description of evaluated data and the match to experiment in both the fission product and actinide regions. Since the scissors mode occurs in the range of a few keV to a few MeV, it may also impact the neutron capture cross sections of neutron-rich nuclei that participate in the rapid neutron capture process of nucleosynthesis. We comment on the possible impact to nucleosynthesis by evaluating neutron capture rates for neutron-rich nuclei with the M 1 scissors mode active.

Initial eccentricity in deformed {sup 197}Au+{sup 197}Au and {sup 238}U+{sup 238}U collisions at {radical}(s{sub NN})=200 GeV at the BNL Relativistic Heavy Ion Collider

DOE Office of Scientific and Technical Information (OSTI.GOV)

Filip, Peter; Lednicky, Richard; Masui, Hiroshi

2009-11-15

Initial eccentricity and eccentricity fluctuations of the interaction volume created in relativistic collisions of deformed {sup 197}Au and {sup 238}U nuclei are studied using optical and Monte Carlo (MC) Glauber simulations. It is found that the nonsphericity noticeably influences the average eccentricity in central collisions, and eccentricity fluctuations are enhanced from deformation. Quantitative results are obtained for Au+Au and U+U collisions at energy {radical}(s{sub NN})=200 GeV.

A comprehensive characterization of asphalt mixtures in compression.

DOT National Transportation Integrated Search

2013-08-01

Permanent deformation (i.e., rutting) is one of the major distresses in asphalt pavements, and it consists of : irrecoverable deformation due to viscoplastic flow and viscofracture fatigue damage. The mechanisms of rutting have not : been well addres...

Roles of endothelial A-type lamins in migration of T cells on and under endothelial layers

NASA Astrophysics Data System (ADS)

Song, Kwang Hoon; Lee, Jaehyun; Park, Hyoungjun; Kim, Hye Mi; Park, Jeehun; Kwon, Keon Woo; Doh, Junsang

2016-03-01

Stiff nuclei in cell-dense microenvironments may serve as distinct biomechanical cues for cell migration, but such a possibility has not been tested experimentally. As a first step addressing this question, we altered nuclear stiffness of endothelial cells (ECs) by reducing the expression of A-type lamins using siRNA, and investigated the migration of T cells on and under EC layers. While most T cells crawling on control EC layers avoided crossing over EC nuclei, a significantly higher fraction of T cells on EC layers with reduced expression of A-type lamins crossed over EC nuclei. This result suggests that stiff EC nuclei underlying T cells may serve as “duro-repulsive” cues to direct T cell migration toward less stiff EC cytoplasm. During subendothelial migration under EC layers with reduced expression of A-type lamins, T cells made prolonged contact and substantially deformed EC nuclei, resulting in reduced speed and directional persistence. This result suggests that EC nuclear stiffness promotes fast and directionally persistent subendothelial migration of T cells by allowing minimum interaction between T cells and EC nuclei.

New particle formation events as a source for cloud condensation nuclei in an urban environment

NASA Astrophysics Data System (ADS)

Wonaschütz, Anna; Burkart, Julia; Wagner, Robert; Reischl, Georg; Steiner, Gerhard; Hitzenberger, Regina

2014-05-01

Nucleation and growth events have been observed in many remote, urban and rural environments. The new particles can contribute significantly to cloud condensation nuclei concentrations, after growing into the appropriate size range (Kerminen et al., 2012). Several studies have attempted to quantify this contribution (e.g. Asmi et al., 2011, Matsui et al., 2013), but only a limited number of them to date have used simultaneous measurements of CCN concentrations and particle size distributions for this purpose (e.g. Levin et al., 2012). In this study, a data set from an urban background station, consisting of 22 months of size distribution and 12 months of CCN concentration measurements (Burkart et al., 2011, Burkart et al., 2012) with 10 months of overlapping measurements is combined to explore the variability of CCN concentrations, their possible causes, and the contribution of nucleation and growth events to CCN concentrations. Consistent with observations in many other locations, nucleation and growth events occur on 30% of all days in spring and summer, on 11% of days in fall and on 4% of days in winter. This suggests a potentially large source of CCN from nucleation and growth events, particularly in the warm season. We acknowledge funding from FWF (Austrian Science Fund) P19515-N20 References: Asmi E., Kivekas, N., Kerminen, V. M., Komppula, M., Hyvarinen, A. P., Hatakka, J., Viisanen, Y., and Lihavainen, H.: Secondary new particle formation in Northern Finland Pallas site between the years 2000 and 2010, Atmos. Chem. Phys., 11, 12959-12972, doi: 10.5194/acp-11-12959-2011, 2011 Burkart J., Steiner, G., Reischl, G., and Hitzenberger, R.: Long-term study of cloud condensation nuclei (CCN) acticvation of the atmospheric aerosol in Vienna, Atmos. Environ., 45, 5751-5759, doi: 10.1016/j.atmosenv.2011.07.022, 2011. Burkart J., Hitzenberger, R., Reischl, G., Bauer, H., Leder, K., and Puxbaum, H.: Activation of "synthetic ambient" aerosols - relation to chemical composition of particles < 100 nm, Atmos. Environ., 54, 583-591, doi: 10.1016/j.atmosenv.2012.01.063, 2012. Kerminen V.-M., Paramonov, M., Anttila, T., Riipinen, I., Fountoukis, C., Korhonen, H., Asmi, E., Laakso, L., Lihavainen, H., Swietlicki, E., Svenningsson, B., Asmi, A., Pandis, S. N., Kulmala, M., and Petäjä, T.: Cloud condensation nuclei production associated with atmospheric nucleation: a synthesis based on existing literature and new results, Atmos. Chem. Phys., 12, 12037-12059, doi: 10.5194/acp-12-12037-2012, 2012. Levin, E. J. T., Prenni, A. J., Petters, M. D., Kreidenweis, S. M., Sullivan, R. C., Atwood, S. A., Ortega, J., DeMott, P. J., and Smith, J. N.: An annual cycle of size-resolved aerosol hygroscopicity at a forested site in Colorado, J. Geophys. Res., 117, 06201, doi:10.1029/2011JD016854, 2012. Matsui, H., Koike, M., Kondo, Y., Takegawa, N., Wiedensohler, A., Fast, J. D., and Zaveri, R. A.: Impact of new particle formation on the concentrations of aerosols and cloud condensation nuclei around Beijing, J. Geophys. Res., 116, 19208, doi:10.1029/2011JD016025, 2011.

Nuclear magnetic resonance studies of formyltetrahydrofolate synthetase interactions with formate and methylammonium ion.

PubMed

Wendland, M F; Stevens, T H; Buttlaire, D H; Everett, G W; Himes, R H

1983-02-15

Using nuclear magnetic resonance techniques, we have measured the internuclear distances separating the nucleotide-bound metal from the carbon and hydrogen nuclei of formate as well as the carbon of methylammonium cation when bound to formyltetrahydrofolate synthetase. Measurements were made of the paramagnetic effect on the spin-lattice relaxation rates (1/T1) of 13C and 1H nuclei arising from the replacement of Mg2+ with Mn2+, which binds to the enzyme in the form of a metal-nucleotide complex. Distances from Mn2+ to the formate carbon and proton were found to be 6.3 and 7.4 A, respectively, in the E . ATP . Mn2+ . formate complex and 6.0 and 7.1 A, respectively, in the E . ADP . Mn2+ . formate complex. When tetrahydrofolate was added to the latter complex, the exchange of formate was greatly reduced and became rate limiting for relaxation. These results are consistent with substantial conformational effects produced by the binding of the cofactor. The distance from Mn2+ to the methylammonium carbon in the E . ADP . Mn2+ . CH3NH+3, E . ADP . Mn2+ . formate . CH3NH3+, and E . ADP . Mn2+ . tetrahydrofolate . CH3NH3+ complexes was estimated to be in the range of 7.4-12 A. However, in the E . ADP . Mn2+ formate . tetrahydrofolate . CH3NH3+ complex, the data suggest that exchange of cation contributes significantly to relaxation. These results, combined with other known features of the enzyme, suggest that there may be a monovalent cation site within the active site of the enzyme.

New Global Calculation of Nuclear Masses and Fission Barriers for Astrophysical Applications

NASA Astrophysics Data System (ADS)

Möller, P.; Sierk, A. J.; Bengtsson, R.; Ichikawa, T.; Iwamoto, A.

2008-05-01

The FRDM(1992) mass model [1] has an accuracy of 0.669 MeV in the region where its parameters were determined. For the 529 masses that have been measured since, its accuracy is 0.46 MeV, which is encouraging for applications far from stability in astrophysics. We are developing an improved mass model, the FRDM(2008). The improvements in the calculations with respect to the FRDM(1992) are in two main areas. (1) The macroscopic model parameters are better optimized. By simulation (adjusting to a limited set of now known nuclei) we can show that this actually makes the results more reliable in new regions of nuclei. (2) The ground-state deformation parameters are more accurately calculated. We minimize the energy in a four-dimensional deformation space (ɛ2, V3, V4, V6,) using a grid interval of 0.01 in all 4 deformation variables. The (non-finalized) FRDM (2008-a) has an accuracy of 0.596 MeV with respect to the 2003 Audi mass evaluation before triaxial shape degrees of freedom are included (in progress). When triaxiality effects are incorporated preliminary results indicate that the model accuracy will improve further, to about 0.586 MeV. We also discuss very large-scale fission-barrier calculations in the related FRLDM (2002) model, which has been shown to reproduce very satisfactorily known fission properties, for example barrier heights from 70Se to the heaviest elements, multiple fission modes in the Ra region, asymmetry of mass division in fission and the triple-humped structure found in light actinides. In the superheavy region we find barriers consistent with the observed half-lives. We have completed production calculations and obtain barrier heights for 5254 nuclei heavier than A = 170 for all nuclei between the proton and neutron drip lines. The energy is calculated for 5009325 different shapes for each nucleus and the optimum barrier between ground state and separated fragments is determined by use of an ``immersion'' technique.

Aerodynamic effects of corrugation and deformation in flapping wings of hovering hoverflies.

PubMed

Du, Gang; Sun, Mao

2012-05-07

We investigated the aerodynamic effects of wing deformation and corrugation of a three-dimensional model hoverfly wing at a hovering condition by solving the Navier-Stokes equations on a dynamically deforming grid. Various corrugated wing models were tested. Insight into whether or not there existed significant aerodynamic coupling between wing deformation (camber and twist) and wing corrugation was obtained by comparing aerodynamic forces of four cases: a smooth-plate wing in flapping motion without deformation (i.e. a rigid flat-plate wing in flapping motion); a smooth-plate wing in flapping motion with deformation; a corrugated wing in flapping motion without deformation (i.e. a rigid corrugated wing in flapping motion); a corrugated wing in flapping motion with deformation. There was little aerodynamic coupling between wing deformation and corrugation: the aerodynamic effect of wing deformation and corrugation acting together was approximately a superposition of those of deformation and corrugation acting separately. When acting alone, the effect of wing deformation was to increase the lift by 9.7% and decrease the torque (or aerodynamic power) by 5.2%, and that of wing corrugation was to decrease the lift by 6.5% and increase the torque by 2.2%. But when acting together, the wing deformation and corrugation only increased the lift by ~3% and decreased the torque by ~3%. That is, the combined aerodynamic effect of deformation and corrugation is rather small. Thus, wing corrugation is mainly for structural, not aerodynamic, purpose, and in computing or measuring the aerodynamic forces, using a rigid flat-plate wing to model the corrugated deforming wing at hovering condition can be a good approximation. Copyright © 2012 Elsevier Ltd. All rights reserved.

Temperature dependence of dynamic deformation in FCC metals, aluminum and invar

DOE PAGES

Chen, Laura; Swift, D. C.; Austin, R. A.; ...

2017-01-01

Laser-driven shock experiments were performed on fcc metals, aluminum and invar, at a range of initial temperatures from approximately 120-800 K to explore the effect of initial temperature on dynamic strength properties at strain rates reaching up to 10 7 s -1. In aluminum, velocimetry data demonstrated an increase of peak stress of the elastic wave, σ E, with initial temperature. Alternatively, for invar, σ E exhibits little-to-no decrease over the same initial temperature range. Aluminum’s unusual deformation behavior is found to primarily be due to anharmonic vibrational effects. Differences in the magnetic structure of aluminum and invar can accountmore » for discrepancies in high rate deformation behavior.« less

Deformation Microstructures of the Yugu Peridotites in the Gyeonggi Massif, Korea: Implications for Olivine Fabric Transition in Mantle Shear Zones

NASA Astrophysics Data System (ADS)

Jung, H.; Park, M.

2017-12-01

Large-scale emplaced peridotite bodies may provide insights into plastic deformation process and tectonic evolution in the mantle shear zone. Due to the complexity of deformation microstructures and processes in natural mantle rocks, the evolution of pre-existing olivine fabrics is still not well understood. In this study, we examine well-preserved transitional characteristics of microstructures and olivine fabrics developed in a mantle shear zone from the Yugu peridotite body, the Gyeonggi Massif, Korean Peninsula. The Yugu peridotite body predominantly comprises spinel harzburgite together with minor lherzolite, dunite, and clinopyroxenite. We classified highly deformed peridotites into four textural types based on their microstructural characteristics: proto-mylonite; proto-mylonite to mylonite transition; mylonite; and ultra-mylonite. Olivine fabrics changed from A-type (proto-mylonite) via D-type (mylonite) to E-type (ultra-mylonite). Olivine fabric transition is interpreted as occurring under hydrous conditions at low temperature and high strain, because of characteristics such as Ti-clinohumite defects (and serpentine) and fluid inclusion trails in olivine, and a hydrous mineral (pargasite) in the matrix, especially in the ultra-mylonitic peridotites. Even though the ultra-mylonitic peridotites contained extremely small (24-30 μm) olivine neoblasts, the olivine fabrics showed a distinct (E-type) pattern rather than a random one. Analysis of the lattice preferred orientation strength, dislocation microstructures, recrystallized grain-size, and deformation mechanism maps of olivine suggest that the proto-mylonitic, mylonitic, and ultra-mylonitic peridotites were deformed by dislocation creep (A-type), DisGBS (D-type), and combination of dislocation and diffusion creep (E-type), respectively.

Tensile and creep properties of the experimental oxide dispersion strengthened iron-base sheet alloy MA-956E at 1365 K

NASA Technical Reports Server (NTRS)

Whittenberger, J. D.

1978-01-01

A study of the 1365 K tensile properties, creep characteristics and residual room temperature properties after creep testing of the experimental oxide dispersion strengthened iron-base alloy MA-956E (Fe-20Cr-4.5Al-0.5Ti-0.5Y2O3) was conducted. The 1365 K tensile properties, particularly ductility, are strongly dependent on strain rate. It appears that MA-956E does not easily undergo slow plastic deformation. Rather than deform under creep loading conditions, the alloy apparently fails by a crack nucleation and growth mechanism. Fortunately, there appears to be a threshold stress below which crack nucleation and/or growth does not occur.

a HARTREE-FOCK Nuclear Mass Table

NASA Astrophysics Data System (ADS)

Goriely, S.; Tondeur, F.; Pearson, J. M.

2001-03-01

We present the first complete nuclear mass table, HFBCS-1, to be based on the Hartree-Fock-BCS method. The force used, MSk7, is a 10-parameter Skyrme force, along with a 4-parameter δ-function pairing force and a 2-parameter phenomenological Wigner term. Our tabulation presents 9200 nuclei, including all those lying between the drip lines over the range Z, N≥8 and Z≤120. The root-mean-square error of our fit to the 1888 nuclei in this range for which measured masses are given in the 1995 Audi-Wapstra compilation is 0.738 MeV. In addition to the calculated masses, we show the calculated neutron- and proton-separation energies, and beta-decay energies. We also give for each nucleus in the table the calculated values for the deformation parameters and deformation energy (with axial and left-right symmetry assumed), and for the charge radius.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gulshani, P., E-mail: matlap@bell.net

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

Experimental signature of collective enhancement in nuclear level density

NASA Astrophysics Data System (ADS)

Pandit, Deepak; Bhattacharya, Srijit; Mondal, Debasish; Roy, Pratap; Banerjee, K.; Mukhopadhyay, S.; Pal, Surajit; De, A.; Dey, Balaram; Banerjee, S. R.

2018-04-01

We present a probable experimental signature of collective enhancement in the nuclear level density (NLD) by measuring the neutron and the giant dipole resonance (GDR) γ rays emitted from the rare-earth 169Tm compound nucleus populated at 26.1 MeV excitation energy. An enhanced yield is observed in both neutron and γ -ray spectra corresponding to the same excitation energy in the daughter nuclei. The enhancement could only be reproduced by including a collective enhancement factor in the Fermi gas model of NLD to explain the neutron and GDR spectra simultaneously. The experimental results show that the relative enhancement factor is of the order of 10 and the fadeout occurs at ˜14 MeV excitation energy, much before the commonly accepted transition from deformed to spherical shape. We also explain how the collective enhancement contribution changes the inverse level density parameter k from 8 to 9.5 MeV observed recently in several deformed nuclei.

First Direct Mass Measurements of Nuclides around Z =100 with a Multireflection Time-of-Flight Mass Spectrograph

NASA Astrophysics Data System (ADS)

Ito, Y.; Schury, P.; Wada, M.; Arai, F.; Haba, H.; Hirayama, Y.; Ishizawa, S.; Kaji, D.; Kimura, S.; Koura, H.; MacCormick, M.; Miyatake, H.; Moon, J. Y.; Morimoto, K.; Morita, K.; Mukai, M.; Murray, I.; Niwase, T.; Okada, K.; Ozawa, A.; Rosenbusch, M.; Takamine, A.; Tanaka, T.; Watanabe, Y. X.; Wollnik, H.; Yamaki, S.

2018-04-01

The masses of 246Es, 251Fm, and the transfermium nuclei Md-252249 and 254No, produced by hot- and cold-fusion reactions, in the vicinity of the deformed N =152 neutron shell closure, have been directly measured using a multireflection time-of-flight mass spectrograph. The masses of 246Es and 249,250,252Md were measured for the first time. Using the masses of Md,250249 as anchor points for α decay chains, the masses of heavier nuclei, up to 261Bh and 266Mt, were determined. These new masses were compared with theoretical global mass models and demonstrated to be in good agreement with macroscopic-microscopic models in this region. The empirical shell gap parameter δ2 n derived from three isotopic masses was updated with the new masses and corroborates the existence of the deformed N =152 neutron shell closure for Md and Lr.

Coulomb excitation of a radioactive beam of rubidium-78

NASA Astrophysics Data System (ADS)

Schwartz, Jazmin

2000-11-01

Much attention has been focused on the structure of nuclei far from stability and on the technologies necessary to study them. The increased interest in these nuclei is due to their importance in generalizing nuclear structure, and to the crucial roles many of them play in astrophysical processes. One approach being investigated to reach the driplines is the construction of radioactive beam facilities for nuclear physics research at the drip- lines. One of the more promising tools for research into the structure of these exotic nuclei is the use of Coulomb excitation reactions. This process has the advantage of having relatively large excitation cross sections (in the order of barns) which are directly calculable, as they involve only the matrix elements of the electro-magnetic interaction. Thus, experimental observables can be directly related to nuclear matrix elements. Coulomb excitation is normally inferred by measuring the gamma-rays emitted during the subsequent de-excitation of states. When radioactive beams are used, a background of gamma-rays arising from β+ decay of the beam is present, which can be intense. The presently available radioactive beams are usually not intense (<10 5) pps, so the gamma-rays of interest are never strong and it is difficult to suppress gamma-rays from background processes. Nevertheless, by exploiting the characteristics of prompt excitation, photons emitted through the Coulomb excitation mechanism can be separated from backgrounds by measuring gamma-rays emitted with appropriate time and intensity correlations with respect to the scattered ions. This thesis reports on a ``proof-of-principle'' experiment involving the Coulomb excitation of a low energy (E/A < 1.5 MeV/u), low intensity (~104 particles per second) beam of radioactive nuclei. We have produced a secondary radioactive beam of 78Rb and Coulomb re- excited it. The beam was produced in the fusion evaporation reaction 24Mg(58Ni,3pn)78Rb using beams delivered by the Argonne National Laboratory ATLAS accelerator, at a beam energy of 260 MeV and an intensity of 20 pnA. A gamma-ray spectrum has been extracted consisting of transitions associated with re-excitation of A = 78 isobars. We see the excitation of stable 78Kr which is well known and serves as a reference. Gamma-rays associated with excitation of 78Rbgs, R78b4+ , R78b4- , and 78Sr were also observed. There are also indications of the excitation of the A = 75 impurities of the beam. Calculation of the relative yields indicate that 78Rbgs and R78b4+,4- are all very deformed (β2 ~ 0.4), and that the isomers have partial alignment of quasi-particles with J = 4 and K = 3 at their bandheads. This incomplete alignment is consistent with calculations coupling g/ particles to a highly deformed core.

Photonuclear interactions of ultrahigh energy cosmic rays and their astrophysical consequences

NASA Technical Reports Server (NTRS)

Puget, J. L.; Stecker, F. W.; Bredekamp, J. H.

1976-01-01

Results are presented for detailed Monte Carlo calculations of the interaction histories of ultrahigh-energy cosmic-ray nuclei with intergalactic radiation fields, using improved estimates of these fields and empirical determinations of photonuclear cross sections, including multinuclear disintegrations for nuclei up to Fe-56. Intergalactic and galactic energy-loss rates and nucleon-loss rates for nuclei up to Fe-56 are also given. Astrophysical implications are discussed in terms of expected features in the cosmic-ray spectrum between 10 to the 18th and 10 to the 21st power eV for the universal and supercluster origin hypotheses. The results of these calculations indicate that ultrahigh-energy cosmic rays cannot be universal in origin regardless of whether they are protons or nuclei. Both the supercluster and galactic origin hypotheses, however, are possible regardless of nuclear composition.

Lead, platinum, and other heavy elements in the primary cosmic radiation - HEAO 3 results

NASA Technical Reports Server (NTRS)

Binns, W. R.; Israel, M. H.; Brewster, N. R.; Fixsen, D. J.; Garrard, T. L.

1985-01-01

An observation of the abundances of cosmic-ray lead-group and platinum-group nuclei is reported, using data from the HEAO 3 Heavy Nuclei Experiment. From an analysis of 580 days of exposure, 322 nuclei were selected with reasonable charge resolution, E at least 1.3 GeV/nucleon and Z at least 50. The data show a defined abundance peak in the 'platinum' region (Z from 74 to 80), a small abundance of 'lead' (Z from 81 to 83), and a significant number of 'secondary' nuclei in the range of Z between 62 and 73. Possible explanations are offered for the deduced ratio in space of 0.25 plus or minus 0.09 for 'Pb/Pt' being distinctly lower than that predicted by any of the standard models for cosmic-ray sources and propagation effects.

Hyperheavy nuclei in covariant density functional theory: the existence and stability

NASA Astrophysics Data System (ADS)

Gyawali, Abhinaya; Agbemava, Sylvester; Afanasjev, Anatoli

2017-09-01

The limits of existence of finite nuclei is one of interesting questions of modern low-energy nuclear physics. A lot of theoretical efforts have been dedicated to the study of superheavy nuclei with Z < 126. However, very little is known about existence and stability of hyperheavy nuclei with proton numbers Z > 126 . Almost all investigations of such nuclei consider only spherical shapes for the ground states. However, the study of superheavy nuclei indicates that such assumption leads in many cases to misinterpretation of the situation. Thus, we performed a systematic investigation of such nuclei for proton numbers from 122 up to 184 and from two-proton drip line up to two-neutron one within the axial relativistic Hartree-Bogoliubov theory. The calculations are carried out in large deformation space extending from megadeformed oblate shapes via spherical ones up to scission configuration. The stability of such nuclei against fission (including triaxial and octupole shapes) and beta-decays have been investigated and the islands of their stability have been defined. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under Award No. DE-SC0013037 and by Department of Energy, National Nuclear Security Administration under Award Number DE-NA0002925.

Enhancing NMR of insensitive nuclei by transfer of SABRE spin hyperpolarization

NASA Astrophysics Data System (ADS)

Pravdivtsev, Andrey N.; Yurkovskaya, Alexandra V.; Zimmermann, Herbert; Vieth, Hans-Martin; Ivanov, Konstantin L.

2016-09-01

We describe the performance of methods for enhancing NMR (Nuclear Magnetic Resonance) signals of "insensitive", but important NMR nuclei, which are based on the SABRE (Signal Amplification By Reversible Exchange) technique, i.e., on spin order transfer from parahydrogen (H2 molecule in its nuclear singlet spin state) to a substrate in a transient organometallic complex. Here such transfer is performed at high magnetic fields by INEPT-type NMR pulse sequences, modified for SABRE. Signal enhancements up to three orders of magnitude are obtained for 15N nuclei; the possibility of sensitive detection of 2D-NMR 1H-15N spectra of SABRE complexes and substrates is demonstrated.

Cross Section Measurements of the Radioactive 107Pd and Stable 105,108Pd Nuclei at J-PARC/MLF/ANNRI

NASA Astrophysics Data System (ADS)

Nakamura, S.; Kimura, A.; Kitatani, F.; Ohta, M.; Furutaka, K.; Goko, S.; Hara, K. Y.; Harada, H.; Hirose, K.; Kin, T.; Koizumi, M.; Oshima, M.; Toh, Y.; Kino, K.; Hiraga, F.; Kamiyama, T.; Kiyanagi, Y.; Katabuchi, T.; Mizumoto, M.; Igashira, M.; Hori, J.; Fujii, T.; Fukutani, S.; Takamiya, K.

2014-05-01

The measurements of the neutron-capture cross sections were performed for the radioactive 107Pd and stable 105,108Pd nuclei by the time-of flight method using an apparatus called “Accurate Neutron-Nucleus Reaction measurement Instrument (ANNRI)” installed at the neutron Beam Line No.4 of the Materials and Life science experimental Facility (MLF) in the J-PARC. The neutron-capture cross sections of 107Pd and 105,108Pd have been measured in the low energy region from the thermal to a few hundreds eV. From the measurements, new information was obtained for some resonances of these Pd nuclei.

Infrared Spectroscopic Imaging for Prostate Pathology Practice

DTIC Science & Technology

2010-03-01

lassification a lgorithm u ses mo rphological f eatures – geometric pr operties of epithelial cells/nuclei and lumens – that are quantified based on H&E stained...images as well as FT-IR images of the samples. By restricting the features used to geometric measures, we sought to m imic t he pa ttern r...be modeled as small elliptical areas in the stained images. This geometrical model is often confounded as multiple nuclei can be so close as to ap

Determination of the charge radii of several light nuclei from precision, high-energy electron elastic scattering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kabir, Al Amin

2015-12-01

Analysis of high-energy electron scattering has been used to determine the charge radii of nuclei for several decades. Recent analysis of the Lamb shift in muonic hydrogen found an r.m.s. radius significantly different than the electron scattering result. To understand this puzzle we have analyzed the "LEDEX" data for the (e, e'p) reaction. This experiment includes measurements on several light nuclei, hydrogen, deuterium, lithium, boron, and carbon. To test our ability to measure absolute cross sections, as well as our ability to extract the charge radius, we tested our technique against the extremely well-measured carbon case and found excellent agreementmore » using the Fourier-Bessel parametrization. We then extended the procedure to boron and lithium, which show nice agreement with the latest theoretical calculations. For hydrogen, we see clearly the limits of this technique and therefore, the charge radius is determined from the traditional extrapolation to q 2 = 0. We will show that there is a model dependence in extracting the charge radius of hydrogen and its unambiguous determination is very difficult with available electron-scattering measurements.« less

Automated seeding-based nuclei segmentation in nonlinear optical microscopy.

PubMed

Medyukhina, Anna; Meyer, Tobias; Heuke, Sandro; Vogler, Nadine; Dietzek, Benjamin; Popp, Jürgen

2013-10-01

Nonlinear optical (NLO) microscopy based, e.g., on coherent anti-Stokes Raman scattering (CARS) or two-photon-excited fluorescence (TPEF) is a fast label-free imaging technique, with a great potential for biomedical applications. However, NLO microscopy as a diagnostic tool is still in its infancy; there is a lack of robust and durable nuclei segmentation methods capable of accurate image processing in cases of variable image contrast, nuclear density, and type of investigated tissue. Nonetheless, such algorithms specifically adapted to NLO microscopy present one prerequisite for the technology to be routinely used, e.g., in pathology or intraoperatively for surgical guidance. In this paper, we compare the applicability of different seeding and boundary detection methods to NLO microscopic images in order to develop an optimal seeding-based approach capable of accurate segmentation of both TPEF and CARS images. Among different methods, the Laplacian of Gaussian filter showed the best accuracy for the seeding of the image, while a modified seeded watershed segmentation was the most accurate in the task of boundary detection. The resulting combination of these methods followed by the verification of the detected nuclei performs high average sensitivity and specificity when applied to various types of NLO microscopy images.

Hubble Space Telescope observations of comet P/Shoemaker-Levy 9 (1993e)

USGS Publications Warehouse

Weaver, H.A.; Feldman, P.D.; A'Hearn, M.F.; Arpigny, C.; Brown, R.A.; Helin, E.F.; Levy, D.H.; Marsden, B.G.; Meech, K.J.; Larson, S.M.; Noll, K.S.; Scotti, J.V.; Sekanina, Z.; Shoemaker, C.S.; Shoemaker, E.M.; Smith, T.E.; Storrs, A.D.; Yeomans, D.K.; Zellner, B.

1994-01-01

The Hubble Space Telescope observed the fragmented comet P/Shoemaker-Levy 9 (1993e) (P indicates that it is a periodic comet) on 1 July 1993. Approximately 20 individual nuclei and their comae were observed in images taken with the Planetary Camera. After subtraction of the comae light, the 11 brightest nuclei have magnitudes between ~23.7 and 24.8. Assuming that the geometric albedo is 0.04, these magnitudes imply that the nuclear diameters are in the range ~2.5 to 4.3 kilometers. If the density of each nucleus is 1 gram per cubic centimeter, the total energy deposited by the impact of these 11 nuclei into Jupiter's atmosphere next July will be ~4 x 1030 ergs (~108 megatons of TNT). This latter number should be regarded as an upper limit because the nuclear magnitudes probably contain a small residual coma contribution. The Faint Object Spectrograph was used to search for fluorescence from OH, which is usually an excellent indicator of cometary activity. No OH emission was detected, and this can be translated into an upper limit on the water production rate of ~2 x 1027 molecules per second.

Coulomb excitation of radioactive 20, 21Na

NASA Astrophysics Data System (ADS)

Schumaker, M. A.; Cline, D.; Hackman, G.; Pearson, C.; Svensson, C. E.; Wu, C. Y.; Andreyev, A.; Austin, R. A. E.; Ball, G. C.; Bandyopadhyay, D.; Becker, J. A.; Boston, A. J.; Boston, H. C.; Buchmann, L.; Churchman, R.; Cifarelli, F.; Cooper, R. J.; Cross, D. S.; Dashdorj, D.; Demand, G. A.; Dimmock, M. R.; Drake, T. E.; Finlay, P.; Gallant, A. T.; Garrett, P. E.; Green, K. L.; Grint, A. N.; Grinyer, G. F.; Harkness, L. J.; Hayes, A. B.; Kanungo, R.; Lisetskiy, A. F.; Leach, K. G.; Lee, G.; Maharaj, R.; Martin, J.-P.; Moisan, F.; Morton, A. C.; Mythili, S.; Nelson, L.; Newman, O.; Nolan, P. J.; Orce, J. N.; Padilla-Rodal, E.; Phillips, A. A.; Porter-Peden, M.; Ressler, J. J.; Roy, R.; Ruiz, C.; Sarazin, F.; Scraggs, D. P.; Waddington, J. C.; Wan, J. M.; Whitbeck, A.; Williams, S. J.; Wong, J.

2009-12-01

The low-energy structures of the radioactive nuclei 20, 21Na have been examined using Coulomb excitation at the TRIUMF-ISAC radioactive ion beam facility. Beams of ˜ 5×106 ions/s were accelerated to 1.7MeV/A and Coulomb excited in a 0.5mg/cm^2 natTi target. Two TIGRESS HPGe clover detectors perpendicular to the beam axis were used for γ -ray detection, while scattered nuclei were observed by the Si detector BAMBINO. For 21Na , Coulomb excitation from the 3/2+ ground state to the first excited 5/2+ state was observed, while for 20Na , Coulomb excitation was observed from the 2+ ground state to the first excited 3+ and 4+ states. For both beams, B ( λ L) values were determined using the 2+ rightarrow 0+ de-excitation in 48Ti as a reference. The resulting B( E2) ↓ value for 21Na is 137±9 e^2fm^4, while the resulting B( λ L) ↓ values for 20Na are 55±6 e^2fm^4 for the 3+ rightarrow 2+ , 35.7±5.7 e^2 fm^4 for the 4+ rightarrow 2+ , and 0.154±0.030 μ_ N^2 for the 4+ rightarrow 3+ transitions. This analysis significantly improves the measurement of the 21Na B( E2) value, and provides the first experimental determination of B( λ L) values for the proton dripline nucleus 20Na .-1

Investigating nuclear shell structure in the vicinity of 78Ni: Low-lying excited states in the neutron-rich isotopes Zn,8280

NASA Astrophysics Data System (ADS)

Shiga, Y.; Yoneda, K.; Steppenbeck, D.; Aoi, N.; Doornenbal, P.; Lee, J.; Liu, H.; Matsushita, M.; Takeuchi, S.; Wang, H.; Baba, H.; Bednarczyk, P.; Dombradi, Zs.; Fulop, Zs.; Go, S.; Hashimoto, T.; Honma, M.; Ideguchi, E.; Ieki, K.; Kobayashi, K.; Kondo, Y.; Minakata, R.; Motobayashi, T.; Nishimura, D.; Otsuka, T.; Otsu, H.; Sakurai, H.; Shimizu, N.; Sohler, D.; Sun, Y.; Tamii, A.; Tanaka, R.; Tian, Z.; Tsunoda, Y.; Vajta, Zs.; Yamamoto, T.; Yang, X.; Yang, Z.; Ye, Y.; Yokoyama, R.; Zenihiro, J.

2016-02-01

The low-lying level structures of nuclei in the vicinity of 78Ni were investigated using in-beam γ -ray spectroscopy to clarify the nature of the nuclear magic numbers Z =28 and N =50 in systems close to the neutron drip line. Nucleon knockout reactions were employed to populate excited states in 80Zn and 82Zn. A candidate for the 41+ level in 80Zn was identified at 1979(30) keV, and the lifetime of this state was estimated to be 136-67+92 ps from a line-shape analysis. Moreover, the energy of the 21+ state in 82Zn is reported to lie at 621(11) keV. The large drop in the 21+ energy at 82Zn indicates the presence of a significant peak in the E (21+) systematics at N =50 . Furthermore, the E (41+) /E (21+) and B (E 2 ;41+→21+) /B (E 2 ;21+→0g.s . +) ratios in 80Zn were deduced to be 1.32 (3 ) and 1 .12-60+80 , respectively. These results imply that 80Zn can be described in terms of two-proton configurations with a 78Ni core and are consistent with a robust N =50 magic number along the Zn isotopic chain. These observations, therefore, indicate a persistent N =50 shell closure in nuclei far from the line of β stability, which in turn suggests a doubly magic structure for 78Ni.

Early stage fatigue damage occurs in bovine tendon fascicles in the absence of changes in mechanics at either the gross or micro-structural level.

PubMed

Shepherd, Jennifer H; Riley, Graham P; Screen, Hazel R C

2014-10-01

Many tendon injuries are believed to result from repetitive motion or overuse, leading to the accumulation of micro-damage over time. In vitro fatigue loading can be used to characterise damage during repeated use and investigate how this may relate to the aetiology of tendinopathy. This study considered the effect of fatigue loading on fascicles from two functionally distinct bovine tendons: the digital extensor and deep digital flexor. Micro-scale extension mechanisms were investigated in fascicles before or after a period of cyclic creep loading, comparing two different measurement techniques - the displacement of a photo-bleached grid and the use of nuclei as fiducial markers. Whilst visual damage was clearly identified after only 300 cycles of creep loading, these visual changes did not affect either gross fascicle mechanics or fascicle microstructural extension mechanisms over the 900 fatigue cycles investigated. However, significantly greater fibre sliding was measured when observing grid deformation rather than the analysis of nuclei movement. Measurement of microstructural extension with both techniques was localised and this may explain the absence of change in microstructural deformation in response to fatigue loading. Alternatively, the data may demonstrate that fascicles can withstand a degree of matrix disruption with no impact on mechanics. Whilst use of a photo-bleached grid to directly measure the collagen is the best indicator of matrix deformation, nuclei tracking may provide a better measure of the strain perceived directly by the cells. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Extra-dimensional Demons: a method for incorporating missing tissue in deformable image registration.

PubMed

Nithiananthan, Sajendra; Schafer, Sebastian; Mirota, Daniel J; Stayman, J Webster; Zbijewski, Wojciech; Reh, Douglas D; Gallia, Gary L; Siewerdsen, Jeffrey H

2012-09-01

A deformable registration method capable of accounting for missing tissue (e.g., excision) is reported for application in cone-beam CT (CBCT)-guided surgical procedures. Excisions are identified by a segmentation step performed simultaneous to the registration process. Tissue excision is explicitly modeled by increasing the dimensionality of the deformation field to allow motion beyond the dimensionality of the image. The accuracy of the model is tested in phantom, simulations, and cadaver models. A variant of the Demons deformable registration algorithm is modified to include excision segmentation and modeling. Segmentation is performed iteratively during the registration process, with initial implementation using a threshold-based approach to identify voxels corresponding to "tissue" in the moving image and "air" in the fixed image. With each iteration of the Demons process, every voxel is assigned a probability of excision. Excisions are modeled explicitly during registration by increasing the dimensionality of the deformation field so that both deformations and excisions can be accounted for by in- and out-of-volume deformations, respectively. The out-of-volume (i.e., fourth) component of the deformation field at each voxel carries a magnitude proportional to the excision probability computed in the excision segmentation step. The registration accuracy of the proposed "extra-dimensional" Demons (XDD) and conventional Demons methods was tested in the presence of missing tissue in phantom models, simulations investigating the effect of excision size on registration accuracy, and cadaver studies emulating realistic deformations and tissue excisions imparted in CBCT-guided endoscopic skull base surgery. Phantom experiments showed the normalized mutual information (NMI) in regions local to the excision to improve from 1.10 for the conventional Demons approach to 1.16 for XDD, and qualitative examination of the resulting images revealed major differences: the conventional Demons approach imparted unrealistic distortions in areas around tissue excision, whereas XDD provided accurate "ejection" of voxels within the excision site and maintained the registration accuracy throughout the rest of the image. Registration accuracy in areas far from the excision site (e.g., > ∼5 mm) was identical for the two approaches. Quantitation of the effect was consistent in analysis of NMI, normalized cross-correlation (NCC), target registration error (TRE), and accuracy of voxels ejected from the volume (true-positive and false-positive analysis). The registration accuracy for conventional Demons was found to degrade steeply as a function of excision size, whereas XDD was robust in this regard. Cadaver studies involving realistic excision of the clivus, vidian canal, and ethmoid sinuses demonstrated similar results, with unrealistic distortion of anatomy imparted by conventional Demons and accurate ejection and deformation for XDD. Adaptation of the Demons deformable registration process to include segmentation (i.e., identification of excised tissue) and an extra dimension in the deformation field provided a means to accurately accommodate missing tissue between image acquisitions. The extra-dimensional approach yielded accurate "ejection" of voxels local to the excision site while preserving the registration accuracy (typically subvoxel) of the conventional Demons approach throughout the rest of the image. The ability to accommodate missing tissue volumes is important to application of CBCT for surgical guidance (e.g., skull base drillout) and may have application in other areas of CBCT guidance.

Extra-dimensional Demons: A method for incorporating missing tissue in deformable image registration

PubMed Central

Nithiananthan, Sajendra; Schafer, Sebastian; Mirota, Daniel J.; Stayman, J. Webster; Zbijewski, Wojciech; Reh, Douglas D.; Gallia, Gary L.; Siewerdsen, Jeffrey H.

2012-01-01

Purpose: A deformable registration method capable of accounting for missing tissue (e.g., excision) is reported for application in cone-beam CT (CBCT)-guided surgical procedures. Excisions are identified by a segmentation step performed simultaneous to the registration process. Tissue excision is explicitly modeled by increasing the dimensionality of the deformation field to allow motion beyond the dimensionality of the image. The accuracy of the model is tested in phantom, simulations, and cadaver models. Methods: A variant of the Demons deformable registration algorithm is modified to include excision segmentation and modeling. Segmentation is performed iteratively during the registration process, with initial implementation using a threshold-based approach to identify voxels corresponding to “tissue” in the moving image and “air” in the fixed image. With each iteration of the Demons process, every voxel is assigned a probability of excision. Excisions are modeled explicitly during registration by increasing the dimensionality of the deformation field so that both deformations and excisions can be accounted for by in- and out-of-volume deformations, respectively. The out-of-volume (i.e., fourth) component of the deformation field at each voxel carries a magnitude proportional to the excision probability computed in the excision segmentation step. The registration accuracy of the proposed “extra-dimensional” Demons (XDD) and conventional Demons methods was tested in the presence of missing tissue in phantom models, simulations investigating the effect of excision size on registration accuracy, and cadaver studies emulating realistic deformations and tissue excisions imparted in CBCT-guided endoscopic skull base surgery. Results: Phantom experiments showed the normalized mutual information (NMI) in regions local to the excision to improve from 1.10 for the conventional Demons approach to 1.16 for XDD, and qualitative examination of the resulting images revealed major differences: the conventional Demons approach imparted unrealistic distortions in areas around tissue excision, whereas XDD provided accurate “ejection” of voxels within the excision site and maintained the registration accuracy throughout the rest of the image. Registration accuracy in areas far from the excision site (e.g., > ∼5 mm) was identical for the two approaches. Quantitation of the effect was consistent in analysis of NMI, normalized cross-correlation (NCC), target registration error (TRE), and accuracy of voxels ejected from the volume (true-positive and false-positive analysis). The registration accuracy for conventional Demons was found to degrade steeply as a function of excision size, whereas XDD was robust in this regard. Cadaver studies involving realistic excision of the clivus, vidian canal, and ethmoid sinuses demonstrated similar results, with unrealistic distortion of anatomy imparted by conventional Demons and accurate ejection and deformation for XDD. Conclusions: Adaptation of the Demons deformable registration process to include segmentation (i.e., identification of excised tissue) and an extra dimension in the deformation field provided a means to accurately accommodate missing tissue between image acquisitions. The extra-dimensional approach yielded accurate “ejection” of voxels local to the excision site while preserving the registration accuracy (typically subvoxel) of the conventional Demons approach throughout the rest of the image. The ability to accommodate missing tissue volumes is important to application of CBCT for surgical guidance (e.g., skull base drillout) and may have application in other areas of CBCT guidance. PMID:22957637

State diagram for adhesion dynamics of deformable capsules under shear flow.

PubMed

Luo, Zheng Yuan; Bai, Bo Feng

2016-08-17

Due to the significance of understanding the underlying mechanisms of cell adhesion in biological processes and cell capture in biomedical applications, we numerically investigate the adhesion dynamics of deformable capsules under shear flow by using a three-dimensional computational fluid dynamic model. This model is based on the coupling of the front tracking-finite element method for elastic mechanics of the capsule membrane and the adhesion kinetics simulation for adhesive interactions between capsules and functionalized surfaces. Using this model, three distinct adhesion dynamic states are predicted, such as detachment, rolling and firm-adhesion. Specifically, the effects of capsule deformability quantified by the capillary number on the transitions of these three dynamic states are investigated by developing an adhesion dynamic state diagram for the first time. At low capillary numbers (e.g. Ca < 0.0075), whole-capsule deformation confers the capsule a flattened bottom in contact with the functionalized surface, which hence promotes the rolling-to-firm-adhesion transition. It is consistent with the observations from previous studies that cell deformation promotes the adhesion of cells lying in the rolling regime. However, it is surprising to find that, at relatively high capillary numbers (e.g. 0.0075 < Ca < 0.0175), the effect of capsule deformability on its adhesion dynamics is far more complex than just promoting adhesion. High deformability of capsules makes their bottom take a concave shape with no adhesion bond formation in the middle. The appearance of this specific capsule shape inhibits the transitions of both rolling-to-firm-adhesion and detachment-to-rolling, and it means that capsule deformation no longer promotes the capsule adhesion. Besides, it is interesting to note that, when the capillary number exceeds a critical value (e.g. Ca = 0.0175), the rolling state no longer appears, since capsules exhibit large deviation from the spherical shape.

Predictions on the modes of decay of odd Z superheavy isotopes within the range 105 ≤ Z ≤ 135

NASA Astrophysics Data System (ADS)

Santhosh, K. P.; Nithya, C.

2018-05-01

The decay modes of 1051 odd Z superheavy nuclei within the range 105 ≤ Z ≤ 135, and their daughter nuclei are studied by comparing the alpha decay half-lives with the spontaneous fission half-lives. The alpha decay half-lives are calculated using the Coulomb and proximity potential model for deformed nuclei (CPPMDN) proposed by Santhosh et al. (2011) and the spontaneous fission half-lives are obtained with the shell-effect dependent formula of Santhosh et al. (Santhosh and Nithya, 2016). For a theoretical comparison, the alpha decay half-lives are also computed with the Coulomb and proximity potential model (CPPM), Viola-Seaborg-Sobiczewski semi-empirical relation (VSS), Universal curve of Poenaru et al. (UNIV), the analytical formula of Royer, and the Universal decay law of Qi et al. (UDL). The predicted decay modes and half-lives were compared with the available experimental results. The proton and neutron separation energies are calculated to identify those nuclei, which decay through proton and neutron emission. From the entire study of odd Z superheavy elements, it is seen that among 1051 nuclei, 233 nuclei exhibit proton emission and 18 nuclei exhibit neutron emission. 56 nuclei are stable against alpha decay with negative Q value for the decay. 92 nuclei show alpha decay followed by spontaneous fission and 9 nuclei show alpha decay followed by proton emission. 39 nuclei decay through full alpha chain and 595 nuclei decay through spontaneous fission. We hope that the study will be very useful for the future experimental investigations in this field.

Computer-assisted bladder cancer grading: α-shapes for color space decomposition

NASA Astrophysics Data System (ADS)

Niazi, M. K. K.; Parwani, Anil V.; Gurcan, Metin N.

2016-03-01

According to American Cancer Society, around 74,000 new cases of bladder cancer are expected during 2015 in the US. To facilitate the bladder cancer diagnosis, we present an automatic method to differentiate carcinoma in situ (CIS) from normal/reactive cases that will work on hematoxylin and eosin (H and E) stained images of bladder. The method automatically determines the color deconvolution matrix by utilizing the α-shapes of the color distribution in the RGB color space. Then, variations in the boundary of transitional epithelium are quantified, and sizes of nuclei in the transitional epithelium are measured. We also approximate the "nuclear to cytoplasmic ratio" by computing the ratio of the average shortest distance between transitional epithelium and nuclei to average nuclei size. Nuclei homogeneity is measured by computing the kurtosis of the nuclei size histogram. The results show that 30 out of 34 (88.2%) images were correctly classified by the proposed method, indicating that these novel features are viable markers to differentiate CIS from normal/reactive bladder.

Evolvement of preformation probability of alpha cluster decay of parent nuclei 84≤Z≤92 having N=126

NASA Astrophysics Data System (ADS)

Kaur, Rupinder; Singh, Bir Bikram; Kaur, Mandeep; Sandhu, B. S.; Kaur, Maninder

2018-05-01

The preformed cluster decay model (PCM) based on collective clusterisation approach of quantum mechanical fragmentation theory (QMFT) has been applied to study the ground state decay of trans-lead parent nuclei 84≤Z≤92 with N=126 emitting α cluster. Within PCM, the α cluster is assumed to be preborn with certain preformation probability P0α before tunneling the potential barrier with penetrability Pα. The nuclear structure information of the emitted α cluster is carried out by P0α . The present work reveals that the relative P0α found to increase as the Z number of parent nuclei moves away from magic proton shell closure i.e. Z=82. It is observed that Pα also increases, consequently, shorter half life T1/2 α of α cluster decay of parent nuclei with increasing Z. The PCM calculated results for the T1/2 α of parent nuclei under study are very well compared with available experimental data.

Autologous Minced Muscle Grafts: A Tissue Engineering Therapy for the Volumetric Loss of Skeletal Muscle

DTIC Science & Technology

2013-07-24

report that over the first 16 wk postinjury, MG transplantation 1) promotes remarkable regeneration of innervated muscle fibers within the defect area...i.e., de novo muscle fiber regeneration); 2) reduced evidence of chronic injury in the remaining muscle mass compared with nonrepaired muscles ...cated nuclei in 30% of fibers observed in nonrepaired muscles ); and 3) significantly improves net torque production (i.e., 55% of the functional deficit

Dimuon production in proton-nucleus interactions

NASA Astrophysics Data System (ADS)

Peng, J. C.

Results from the Fermilab experiments E772 and E789 on the Drell-Yan cross sections, quarkonia production, and open-charm production are presented. These data provide information on the parton distributions in the nucleons and nuclei. They also shed light on the origin of the J/(Psi) suppression observed in heavy ion collisions. The physics motivation and the proposed measurements for a new experiment to probe the sea quark distributions in the proton are also discussed.

Critical temperature for shape transition in hot nuclei within covariant density functional theory

NASA Astrophysics Data System (ADS)

Zhang, W.; Niu, Y. F.

2018-05-01

Prompted by the simple proportional relation between critical temperature for pairing transition and pairing gap at zero temperature, we investigate the relation between critical temperature for shape transition and ground-state deformation by taking even-even Cm-304286 isotopes as examples. The finite-temperature axially deformed covariant density functional theory with BCS pairing correlation is used. Since the Cm isotopes are the newly proposed nuclei with octupole correlations, we studied in detail the free energy surface, the Nilsson single-particle (s.p.) levels, and the components of s.p. levels near the Fermi level in 292Cm. Through this study, the formation of octupole equilibrium is understood by the contribution coming from the octupole driving pairs with Ω [N ,nz,ml] and Ω [N +1 ,nz±3 ,ml] for single-particle levels near the Fermi surfaces as it provides a good manifestation of the octupole correlation. Furthermore, the systematics of deformations, pairing gaps, and the specific heat as functions of temperature for even-even Cm-304286 isotopes are discussed. Similar to the relation between the critical pairing transition temperature and the pairing gap at zero temperature Tc=0.6 Δ (0 ) , a proportional relation between the critical shape transition temperature and the deformation at zero temperature Tc=6.6 β (0 ) is found for both octupole shape transition and quadrupole shape transition for the isotopes considered.

Investigation of primary static recrystallization in a NiTiFe shape memory alloy subjected to cold canning compression using the coupling crystal plasticity finite element method with cellular automaton

NASA Astrophysics Data System (ADS)

Zhang, Yanqiu; Jiang, Shuyong; Hu, Li; Zhao, Yanan; Sun, Dong

2017-10-01

The behavior of primary static recrystallization (SRX) in a NiTiFe shape memory alloy (SMA) subjected to cold canning compression was investigated using the coupling crystal plasticity finite element method (CPFEM) with the cellular automaton (CA) method, where the distribution of the dislocation density and the deformed grain topology quantified by CPFEM were used as the input for the subsequent SRX simulation performed using the CA method. The simulation results were confirmed by the experimental ones in terms of microstructures, average grain size and recrystallization fraction, which indicates that the proposed coupling method is well able to describe the SRX behavior of the NiTiFe SMA. The results show that the dislocation density exhibits an inhomogeneous distribution in the deformed sample and the recrystallization nuclei mainly concentrate on zones where the dislocation density is relatively higher. An increase in the compressive deformation degree leads to an increase in nucleation rate and a decrease in grain boundary spaces in the compression direction, which reduces the growth spaces for the SRX nuclei and impedes their further growth. In addition, both the mechanisms of local grain refinement in the incomplete SRX and the influence of compressive deformation degree on the grain size of SRX were vividly illustrated by the corresponding physical models.

Deformation behavior of welded steel sandwich panels under quasi-static loading

DOT National Transportation Integrated Search

2011-03-16

This paper summarizes basic research (i.e., testing and analysis) : conducted to examine the deformation behavior of flat-welded : steel sandwich panels under two types of quasi-static loading: : (1) uniaxial compression; and (2) bending through an i...

Landslide precursory deformation interpretation using ALOS-2/PALSAR-2 InSAR image along Min River in Maoxien, Sichuan Province, China

NASA Astrophysics Data System (ADS)

Sato, H. P.

2017-12-01

Maoxien area in Sichuan Province, China has many landslide. For example, landslide (rock avalanche) occurred on the slope in Xinmocun Village in Maoxeien on 24 June 2017. I produced and interpreetd InSAR image using ALOS/PALSAR data observed on 19 Jul 2007-3 Sep 2007 and on 27 Jan 2011-14 Mar 2011, and ALOS-2/PALSAR-2 data observed on 26 Jul 2015-13 Dec 2015 and on 13 Dec 2015-11 Dec 2016. These images give good coherence and it was easy to identify local landslide surface deformation. As a result, e.g., two slopes were estimated to have local landslide surface deformation; one is at 103.936587 deg E and 32.04462 deg N, another is at 103.674754 deg E and 31.852838 N. However, the slope in Xinmocun Village was not identified as landslide precursory deformation. In the poster I will present more InSAR image observed after 11 Dec 2016 and discuss the possibility of local landslide surface deformaton using InSAR image. ALOS/PALSAR and ALOS-2/PALSAR-2 data were provided by JAXA through Landslide Working Group in JAXA and through Special Research 2015-B-02 of Earthquake Research Institute/Tokyo University. This study was supported by KAKENHI (17H02973).

Deformable Image Registration based on Similarity-Steered CNN Regression.

PubMed

Cao, Xiaohuan; Yang, Jianhua; Zhang, Jun; Nie, Dong; Kim, Min-Jeong; Wang, Qian; Shen, Dinggang

2017-09-01

Existing deformable registration methods require exhaustively iterative optimization, along with careful parameter tuning, to estimate the deformation field between images. Although some learning-based methods have been proposed for initiating deformation estimation, they are often template-specific and not flexible in practical use. In this paper, we propose a convolutional neural network (CNN) based regression model to directly learn the complex mapping from the input image pair (i.e., a pair of template and subject) to their corresponding deformation field. Specifically, our CNN architecture is designed in a patch-based manner to learn the complex mapping from the input patch pairs to their respective deformation field. First, the equalized active-points guided sampling strategy is introduced to facilitate accurate CNN model learning upon a limited image dataset. Then, the similarity-steered CNN architecture is designed, where we propose to add the auxiliary contextual cue, i.e., the similarity between input patches, to more directly guide the learning process. Experiments on different brain image datasets demonstrate promising registration performance based on our CNN model. Furthermore, it is found that the trained CNN model from one dataset can be successfully transferred to another dataset, although brain appearances across datasets are quite variable.

Mössbauer analysis of the magnetic structure of a high-carbon austenitic steel upon deformation and under pressure

NASA Astrophysics Data System (ADS)

Shabashov, V. A.; Korshunov, L. G.; Zamatovskii, A. E.; Litvinov, A. V.

2007-10-01

A large plastic deformation of Hadfield steel (frictional action, shear under pressure, filing, and rolling) leads to the growth of an internal effective field at 57Fe nuclei, magnetic-degeneracy removal in the spectra, and delay of the paraprocess up to room temperature. In the Mössbauer spectrum of the 120G13 Hadfield steel, the reversible formation of a hyperfine structure, which is supposedly connected with magnetic ordering, has been detected in situ upon quasi-hydrostatic compression to 26 GPa. The observed growth of magnetic characteristics upon deformation and under high pressure is explained by the deformation-induced redistribution of carbon with the formation of short-range ordering of oxygen and manganese.

Influence of hadron and atmospheric models on computation of cosmic ray ionization in the atmosphere-Extension to heavy nuclei

NASA Astrophysics Data System (ADS)

Mishev, A. L.; Velinov, P. I. Y.

2014-12-01

In the last few years an essential progress in development of physical models for cosmic ray induced ionization in the atmosphere is achieved. The majority of these models are full target, i.e. based on Monte Carlo simulation of an electromagnetic-muon-nucleon cascade in the atmosphere. Basically, the contribution of proton nuclei is highlighted, i.e. the contribution of primary cosmic ray α-particles and heavy nuclei to the atmospheric ionization is neglected or scaled to protons. The development of cosmic ray induced atmospheric cascade is sensitive to the energy and mass of the primary cosmic ray particle. The largest uncertainties in Monte Carlo simulations of a cascade in the Earth atmosphere are due to assumed hadron interaction models, the so-called hadron generators. In the work presented here we compare the ionization yield functions Y for primary cosmic ray nuclei, such as α-particles, Oxygen and Iron nuclei, assuming different hadron interaction models. The computations are fulfilled with the CORSIKA 6.9 code using GHEISHA 2002, FLUKA 2011, UrQMD hadron generators for energy below 80 GeV/nucleon and QGSJET II for energy above 80 GeV/nucleon. The observed difference between hadron generators is widely discussed. The influence of different atmospheric parametrizations, namely US standard atmosphere, US standard atmosphere winter and summer profiles on ion production rate is studied. Assuming realistic primary cosmic ray mass composition, the ion production rate is obtained at several rigidity cut-offs - from 1 GV (high latitudes) to 15 GV (equatorial latitudes) using various hadron generators. The computations are compared with experimental data. A conclusion concerning the consistency of the hadron generators is stated.

The Energetic Trans-Iron Composition Experiment (ENTICE) on the Heavy Nuclei Explorer (HNX)

NASA Technical Reports Server (NTRS)

Israel, M. H.; Adams, J. H.; Barbier, L. M.; Binns, W. R.; Christian, E. R.; Cummings, A. C.; Cummings, J. R.; Doke, T.; Hasebe, N.; Hayashi, T.;

DOE Office of Scientific and Technical Information (OSTI.GOV)

Biehl, Daniel; Fedynitch, Anatoli; Winter, Walter

We study the Glashow resonance ν-bar {sub e} + e {sup −} → W {sup −} → hadrons at 6.3 PeV as diagnostic of the production processes of ultra-high energy neutrinos. The focus lies on describing the physics of neutrino production from pion decay as accurate as possible by including the kinematics of weak decays and Monte Carlo simulations of pp and pγ interactions. We discuss optically thick (to photohadronic interactions) sources, sources of cosmic ray ''nuclei'' and muon damped sources. Even in the proposed upgrade IceCube-Gen2, a discrimination of scenarios such as pp versus pγ is extremely challenging undermore » realistic assumptions. Nonetheless, the Glashow resonance can serve as a smoking gun signature of neutrino production from photohadronic (Aγ) interactions of heavier nuclei, as the expected Glashow event rate exceeds that of pp interactions. We finally quantify the exposures for which the non-observation of Glashow events exerts pressure on certain scenarios.« less

Theory of Nuclear Quadrupole Interactions in the Chemical Ferromagnet p-Cl-Ph-CH-N=TEMPO

NASA Astrophysics Data System (ADS)

Briere, Tina M.; Jeong, Junho; Sahoo, N.; Das, T. P.; Ohira, S.; Nishiyama, K.; Nagamine, K.

2002-03-01

The study(Junho Jeong et al., Physica B 289-290, 132 (2000).) of the magnetic hyperfine properties of chemical ferromagnets provides valuable information about the electronic spin distributions in the individual molecules. Insights into the electronic charge distributions and their anisotropy can be obtained from electric quadrupole interactions for the different nuclei in these systems. For this purpose we have studied the nuclear quadrupole interactions(T. P. Das and E. L. Hahn "Nuclear Quadrupole Resonance Spectroscopy", Academic Press Inc., New York, 1958.) for the 14^N nuclei in the NO group and the bridge nitrogen, the 17^O nucleus in the NO group and the 35^Cl nucleus in the p-Cl-Ph-CH-N=TEMPO system both by itself and in the presence of trapped μ and Mu. Comparison will be made between our results and available experimental quadrupole coupling constant (e^2qQ) and asymmetry parameter (η) data.

UHECR mass composition measurement at Telescope Array via stereoscopic observation

NASA Astrophysics Data System (ADS)

Stroman, Thomas; Telescope Array Collaboration

2015-04-01

The masses of primary ultra-high-energy cosmic-ray (UHECR) nuclei cannot be measured directly on an individual basis, but constraints on the chemical composition can be inferred from the distributions of observable properties. The atmospheric slant depth at which a UHECR-induced extensive air shower reaches its maximum number of particles, Xmax, is particularly sensitive to the mass of the incident nucleus, occurring earlier in the shower's longitudinal development for heavier nuclei at a given energy. The Telescope Array in west-central Utah, the northern hemisphere's largest UHECR detector, is equipped for accurate Xmax and energy measurements via stereoscopic fluorescence observation. Using data from seven years of operation, we will present Xmax distributions at several energies E >10 18 . 2eV , and compare them to distributions predicted by detailed detector simulations under an assortment of assumed UHECR compositions and high-energy hadronic interaction models.

Dependence of stress-induced omega transition and mechanical twinning on phase stability in metastable β Ti–V alloys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, X.L.; Li, L.; Mei, W.

2015-09-15

Tensile properties and deformation microstructures of a series of binary β Ti–16–22V alloys have been investigated. The results show that the plastic deformation mode changes from the plate-like stress-induced ω phase transformation with a special habit plane of (− 5052){sub ω}//(3 − 3 − 2){sub β} to (332)<113> type deformation twinning with increasing the content of vanadium in the β Ti–16–22 wt.% V alloys. The plate-like stress-induced ω phase has a special orientation relationship with the β phase matrix, i.e., [110]{sub β}//[− 12 − 10]{sub ω}, (3 − 3 − 2){sub β}//(− 5052){sub ω} and (− 55 − 4){sub β}//(30more » − 31){sub ω}. The alloys plastically deformed by stress-induced ω phase transformation exhibit relatively higher yield strength than those deformed via (332)<113> type deformation twinning. It can be concluded that the stability of β phase plays a significant role in plastic deformation mode, i.e., stress-induced ω phase transformation or (332)<113> type deformation twinning, which governs the mechanical property of the β Ti–16–22 wt.% V alloys. - Highlights: • Tensile properties and deformed microstructures of β Ti–16–22V alloys were studied. • Stress-induced ω phase transformation and (332)<113> twinning occur in the alloys. • Stability of β phase plays a significant role in plastic deformation mode. • Plastic deformation mode governs the mechanical property of the alloys.« less

Modification de l'état d'ordre local d'alliages austénitiques Fe-Cr-Ni au cours de la déformation plastique par traction

NASA Astrophysics Data System (ADS)

Aïdi, B.; Bertrand, C.; Viltange, M.; Dimitrov, O.

1993-09-01

The influence of plastic deformation, by extension at room temperature, on electrical resistivity has been determined in four austenitic Fe-Cr-Ni alloys with 16 wt% Cr and 20, 25, 45 or 75 wt% Ni, in two different states of local order. Two experimental methods have been used (4.2 K resistance measurements before and after deformation, continuous resistance measurements during room-temperature extension tests); the possibilities of the second method and the corrections to be applied are particularly discussed. Resistivity is found to slightly increase at the beginning of deformation ( e < 0.05), then to strongly decrease. The amplitude of the observed effects increases with the nickel content, and with the initial degree of local order. In the high deformation range ( e = 0.15), the resistivity decrease varies linearly with the initial contribution of local order to electrical resistivity. These effects are attributed to a destruction of the local order existing in the solid solutions, by the glide of dislocations during plastic deformation.

Stable reflexive sheaves of degree zero on Calabi-Yau manifolds

NASA Astrophysics Data System (ADS)

Nakashima, Tohru

2017-11-01

We give sufficient conditions for the existence of μ-stable reflexive sheaves E on a Calabi-Yau threefold such that the first Chern classes c1(E) satisfy c1(E) ṡH2 = 0 for some ample line bundle H. We also prove a result concerning deformations to construct rank two μ-stable sheaves on arbitrary smooth projective varieties.

Shell Corrections Stabilizing Superheavy Nuclei and Semi-spheroidal Atomic Clusters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Poenaru, Dorin N.

2008-01-24

The macroscopic-microscopic method is used to illustrate the shell effect stabilizing superheavy nuclei and to study the stability of semi-spheroidal clusters deposited on planar surfaces. The alpha decay of superheavy nuclei is calculated using three models: the analytical superasymmetric fission model; the universal curve, and the semiempirical formula taking into account the shell effects. Analytical relationships are obtained for the energy levels of the new semi-spheroidal harmonic oscillator (SSHO) single-particle model and for the surface and curvature energies of the semi-spheroidal clusters. The maximum degeneracy of the SSHO is reached at a super-deformed prolate shape for which the minimum ofmore » the liquid drop model energy is also attained.« less

Vitamin C and E Supplements Enhance the Antioxidant Capacity of Erythrocytes Obtained from Aged Rats.

PubMed

Xiong, Yanlian; Xiong, Yanlei; Zhou, Shuai; Sun, Yanan; Zhao, Yuqi; Ren, Xiaotong; Zhang, Yingfang; Zhang, Naili

2017-04-01

The main purpose of the present study was to investigate the effects of vitamin C and E supplements on the antioxidant capacity of erythrocytes obtained from young and aged rats. Male Wistar rats aged 3 and 24 months were used. Vitamins C and E were injected at doses of 200 mg/kg (day) intraperitoneally in young and aged groups. The antioxidant capacity, oxidant stress parameters, and deformability of red blood cells collected from different age stages were evaluated. An in vitro oxidation system was constructed to explore the mechanisms of antioxidant capacity change in the vitamin treatment groups. Treatment with vitamins C and E can effectively restore the antioxidant capacity and deformability of red blood cells (RBCs) in aged rats. Under in vitro oxidative conditions, an age-dependent decline in the influx rate of L-cysteine was observed. This was significantly improved following treatment with vitamins C and E. We present evidence of an improvement in the antioxidant capacity of RBCs by treatment with vitamins C and E in aged rats. These observations also suggest that treatment with vitamins C and E improves glutathione synthesis by enhancing the influx rate of L-cysteine through the modification of membrane proteins and lipids.

Elasticity of entangled polymer loops: Olympic gels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vilgis, T.A.; Otto, M.

1997-08-01

In this Rapid Communication we present a scaling theory for the elasticity of olympic gels, i.e., gels where the elasticity is a consequence of topology only. It is shown that two deformation regimes exist. The first is the nonaffine deformation regime where the free energy scales linear with the deformation. In the large (affine) deformation regime the free energy is shown to scale as F{proportional_to}{lambda}{sup 5/2} where {lambda} is the deformation ratio. Thus a highly non-Hookian stress-strain relation is predicted. {copyright} {ital 1997} {ital The American Physical Society}

Hardness and deformation mechanisms of highly elastic carbon nitride thin films as studied by nanoindentation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hainsworth, S.V.; Page, T.F.; Sjoestroem, H.

1997-05-01

Carbon nitride (CN{sub x}) thin films (0.18 < x < 0.43), deposited by magnetron sputtering of C in a N{sub 2} discharge, have been observed to be extremely resistant to plastic deformation during surface contact (i.e., exhibit a purely elastic response over large strains). Elastic recoveries as high as 90% have been measured by nanoindentation. This paper addresses the problems of estimating Young`s modulus (E) and hardness (H) in such cases and shows how different strategies involving analysis of both loading and unloading curves and measuring the work of indentation each present their own problems. The results of some cyclicmore » contact experiments are also presented and possible deformation mechanisms in the fullerene-like CN{sub x} structures discussed.« less

A homogeneous 2D deformation of geological interest: Rotation shear

NASA Astrophysics Data System (ADS)

Bastida, Fernando; Bobillo-Ares, Nilo C.; Aller, Jesús; Lisle, Richard J.

2018-07-01

We define a simple two-dimensional deformation called "rotation shear". It has one line of no finite longitudinal strain with invariant direction and another one that rotates with the deformation. An analysis of this deformation is carried out. Rotation shear superficially resembles simple shear but the analysis reveals that the two deformations have very different properties. In general, lines deformed by simple shear show a more complex deformation history and undergo greater longitudinal strain, i.e. are more extended, than lines deformed by rotation shear. Rotation shear is used to explain the development of geological structures such as kink bands, ideal similar folds, crenulation and crenulation cleavage and shear zones.

A versatile triple radiofrequency quadrupole system for cooling, mass separation and bunching of exotic nuclei

NASA Astrophysics Data System (ADS)

Haettner, Emma; Plaß, Wolfgang R.; Czok, Ulrich; Dickel, Timo; Geissel, Hans; Kinsel, Wadim; Petrick, Martin; Schäfer, Thorsten; Scheidenberger, Christoph

2018-02-01

The combination of in-flight separation with a gas-filled stopping cell has opened a new field for experiments with exotic nuclei. For instance, at the SHIP/SHIPTRAP facility at GSI in Darmstadt high-precision mass measurements of rare nuclei have been successfully performed. In order to extend the reach of SHIPTRAP to exotic nuclei that are produced together with high rates of unwanted reaction products, a novel compact radio frequency quadrupole (RFQ) system has been developed. It implements ion cooling, identification and separation according to mass numbers and bunching capabilities. The system has a total length of one meter only and consists of an RFQ cooler, an RFQ mass filter and an RFQ buncher. A mass resolving power (FWHM) of 240 at a transmission efficiency of 90% has been achieved. The suppression of contaminants from neighboring masses by more than four orders of magnitude has been demonstrated at rates exceeding 106 ions/s. A longitudinal emittance of 0.45 eV μs has been achieved with the RFQ buncher, which will enable improved time-of-flight mass spectrometry downstream of the device. With this triple RFQ system the measurement of e.g. N= Z nuclides in the region up to tin will become possible at SHIPTRAP. The technology is also well suited for other rare-isotope facilities with experimental setups behind a stopping cell, such as the fragment separator FRS with the FRS Ion Catcher at GSI.

Quadrupole collectivity in 42Ca from low-energy Coulomb excitation with AGATA

NASA Astrophysics Data System (ADS)

Hadyńska-Klęk, K.; Napiorkowski, P. J.; Zielińska, M.; Srebrny, J.; Maj, A.; Azaiez, F.; Valiente Dobón, J. J.; Kicińska-Habior, M.; Nowacki, F.; Naïdja, H.; Bounthong, B.; Rodríguez, T. R.; de Angelis, G.; Abraham, T.; Anil Kumar, G.; Bazzacco, D.; Bellato, M.; Bortolato, D.; Bednarczyk, P.; Benzoni, G.; Berti, L.; Birkenbach, B.; Bruyneel, B.; Brambilla, S.; Camera, F.; Chavas, J.; Cederwall, B.; Charles, L.; Ciemała, M.; Cocconi, P.; Coleman-Smith, P.; Colombo, A.; Corsi, A.; Crespi, F. C. L.; Cullen, D. M.; Czermak, A.; Désesquelles, P.; Doherty, D. T.; Dulny, B.; Eberth, J.; Farnea, E.; Fornal, B.; Franchoo, S.; Gadea, A.; Giaz, A.; Gottardo, A.; Grave, X.; Grębosz, J.; Görgen, A.; Gulmini, M.; Habermann, T.; Hess, H.; Isocrate, R.; Iwanicki, J.; Jaworski, G.; Judson, D. S.; Jungclaus, A.; Karkour, N.; Kmiecik, M.; Karpiński, D.; Kisieliński, M.; Kondratyev, N.; Korichi, A.; Komorowska, M.; Kowalczyk, M.; Korten, W.; Krzysiek, M.; Lehaut, G.; Leoni, S.; Ljungvall, J.; Lopez-Martens, A.; Lunardi, S.; Maron, G.; Mazurek, K.; Menegazzo, R.; Mengoni, D.; Merchán, E.; Męczyński, W.; Michelagnoli, C.; Million, B.; Myalski, S.; Napoli, D. R.; Niikura, M.; Obertelli, A.; Özmen, S. F.; Palacz, M.; Próchniak, L.; Pullia, A.; Quintana, B.; Rampazzo, G.; Recchia, F.; Redon, N.; Reiter, P.; Rosso, D.; Rusek, K.; Sahin, E.; Salsac, M.-D.; Söderström, P.-A.; Stefan, I.; Stézowski, O.; Styczeń, J.; Theisen, Ch.; Toniolo, N.; Ur, C. A.; Wadsworth, R.; Wasilewska, B.; Wiens, A.; Wood, J. L.; Wrzosek-Lipska, K.; Ziębliński, M.

2018-02-01

A Coulomb-excitation experiment to study electromagnetic properties of 42Ca was performed using a 170-MeV calcium beam from the TANDEM XPU facility at INFN Laboratori Nazionali di Legnaro. γ rays from excited states in 42Ca were measured with the AGATA spectrometer. The magnitudes and relative signs of ten E 2 matrix elements coupling six low-lying states in 42Ca, including the diagonal E 2 matrix elements of 21+ and 22+ states, were determined using the least-squares code gosia. The obtained set of reduced E 2 matrix elements was analyzed using the quadrupole sum rule method and yielded overall quadrupole deformation for 01,2 + and 21,2 + states, as well as triaxiality for 01,2 + states, establishing the coexistence of a weakly deformed ground-state band and highly deformed slightly triaxial sideband in 42Ca. The experimental results were compared with the state-of-the-art large-scale shell-model and beyond-mean-field calculations, which reproduce well the general picture of shape coexistence in 42Ca.

Fission and Properties of Neutron-Rich Nuclei

NASA Astrophysics Data System (ADS)

Hamilton, Joseph H.; Ramayya, A. V.; Carter, H. K.

2008-08-01

Opening session. Nuclear processes in stellar explosions / M. Wiescher. In-beam [symbol]-ray spectroscopy of neutron-rich nuclei at NSCL / A. Gade -- Nuclear structure I. Shell-model structure of neutron-rich nuclei beyond [symbol]Sn / A. Covello ... [et al.]. Shell structure and evolution of collectivity in nuclei above the [symbol]Sn core / S. Sarkar and M. S. Sarkar. Heavy-ion fusion using density-constrained TDHF / A. S. Umar and V. E. Oberacker. Towards an extended microscopic theory for upper-fp shell nuclei / K. P. Drumev. Properties of the Zr and Pb isotopes near the drip-line / V. N. Tarasov ... [et al.]. Identification of high spin states in [symbol] Cs nuclei and shell model calculations / K. Li ... [et al.]. Recent measurements of spherical and deformed isomers using the Lohengrin fission-fragment spectrometer / G. S. Simpson ... [et al.] -- Nuclear structure II. Nuclear structure investigation with rare isotope spectroscopic investigations at GSI / P. Boutachkov. Exploring the evolution of the shell structures by means of deep inelastic reactions / G. de Anaelis. Probing shell closures in neutron-rich nuclei / R. Krücken for the S277 and REX-ISOLDEMINIBALL collaborations. Structure of Fe isotopes at the limits of the pf-shell / N. Hoteling ... [et al.]. Spectroscopy of K isomers in shell-stabilized trans-fermium nuclei / S. K. Tandel ... [et al.] -- Radioactive ion beam facilities. SPIRAL2 at GANIL: a world leading ISOL facility for the next decade / S. Gales. New physics at the International Facility for Antiproton and Ion Research (FAIR) next to GSI / I. Augustin ... [et al.]. Radioactive beams from a high powered ISOL system / A. C. Shotter. RlKEN RT beam factory / T. Motobayashi. NSCL - ongoing activities and future perspectives / C. K. Gelbke. Rare isotope beams at Argonne / W. F. Henning. HRIBF: scientific highlights and future prospects / J. R. Beene. Radioactive ion beam research done in Dubna / G. M. Ter-Akopian ... [et al.] -- Fission I. Fission-fragment spectroscopy with STEFF / A. G. Smith ... [et al.]. Gamma ray multiplicity of [symbol]Cf spontaneous fission using LiBerACE / D. L. Bleuel ... [et al.]. Excitation energy dependence of fragment mass and total kinetic energy distributions in proton-induced fission of light actinides / I. Nishinaka ... [et al.]. A dynamical calculation of multi-modal nuclear fission / T. Wada and T. Asano. Structure of fission potential energy surfaces in ten-dimensional spaces / V. V. Pashkevich, Y. K Pyatkov and A. V. Unzhakova. A possible enhancement of nuclear fission in scattering with low energy charged particles / V. Gudkov. Dynamical multi-break processes in the [symbol]Sn + [symbol]Ni system at 35 MeV/Nucleon / M. Papa and ISOSPIN-RE VERSE collaboration -- New experimental techniques. MTOF - a high resolution isobar separator for studies of exotic decays / A. Piechaczek ... [et al.]. Development of ORRUBA: a silicon array for the measurement of transfer reactions in inverse kinematics / S. D. Pain ... [et al.]. Indian national gamma array: present & future / R. K. Bhowmik. Absolute intensities of [symbol] rays emitted in the decay of [symbol]U / H. C. Griffin -- Superheavy elements theory and experiments / M. G. Itkis ... [et al.]. Study of superheavy elements at SHIP / S. Hofinann. Heaviest nuclei from [symbol]Ca-induced reactions / Yu. Ts. Oaanessian. Superheavy nuclei and giant nuclear systems / W. Greiner and V. Zagrebaev. Fission approach to alpha-decay of superheavy nuclei / D.N. Poenaru and W. Greiner. Superheavy elements in the Magic Islands / C. Samanta. Relativistic mean field studies of superheavy nuclei / A. V. Afanas jev. Understanding the synthesis of the heaviest nuclei / W. Loveland -- Mass measurements and g-factors. G factor measurements in neutron-rich [symbol]Cf fission fragments, measured using the gammasphere array / R. Orlandi ... [et al.]. Technique for measuring angular correlations and g-factors in neutron rich nuclei produced by the spontaneous fission of [symbol]Cf / A. V. Daniel ... [et al.]. Magnetic moment measurements in a radioactive beam environment / N. Benczer-Koller and G. Kumbartzki. g-Factor measurements of picosecond states: opportunities and limitations of the recoil-in-vacuum method / N. J. Stone ... [et al.]. Precision mass measurements and trap-assisted spectroscopy of fission products from Ni to Pd / A. Jokinen -- Fission II. Fission research at IRMM / F.-J. Hambsch. Fission yield measurements at the IGISOL facility with JYFLTRAP / H. Penttilä ... [et al.]. Fission of radioactive beams and dissipation in nuclear matter / A. Heinz (for the CHARMS collaboration). Fission of [symbol]U at 80 MeVlu and search for new neutron-rich isotopes / C.M. Folden, III ... [et al.]. Measurement of the average energy and multiplicity of prompt-fission neutrons and gamma rays from [symbol], [symbol], and [symbol] for incident neutron energies of 1 to 200 MeV / R. C. Haight ... [et al.]. Fission measurements with DANCE / M. Jandel ... [et al.]. Measured and calculated neutron-induced fission cross sections of [symbol]Pu / F. Tovesson and T. S. Hill. The fission barrier landscape / L. Phair and L. G. Moretto. Fast neutron-induced fission of some actinides and sub-actinides / A. B. Lautev ... [et al.] -- Fission III/Nuclear structure III. Complex structure in even-odd staggering of fission fragment yields / M. Caamāno and F. Rejmund. The surrogate method: past, present and future / S. R. Lesher ... [et al]. Effects of nuclear incompressibility on heavy-ion fusion / H. Esbensen and Ş. Mişicu. High spin states in [symbol]Pm / A. Dhal ... [et al]. Structure of [symbol]Sm, spherical vibrator versus softly deformed rotor / J. B. Gupta -- Astrophysics. Measuring the astrophysical S-factor in plasmas / A. Bonasera ... [et al.]. Is there shell quenching or shape coexistence in Cd isotopes near N = 82? / J. K. Hwang, A. V. Ramayya and J. H. Hamilton. Spectroscopy of neutron-rich palladium and cadmium isostopes near A= 120 / M. A. Stoyer and W. B. Walters -- Nuclear structure IV. First observation of new neutron-rich magnesium, aluminum and silicon isotopes / A. Stolz ... [et al.]. Spectroscopy of [symbol]Na revolution of shell structure with isospin / V. Tripathi ... [et al.]. Rearrangement of proton single particle orbitals in neutron-rich potassium isotopes - spectroscopy of [symbol]K / W. Królas ... [et al.]. Laser spectroscopy and the nature of the shape transition at N [symbol] 60 / B. Cheal ... [et al.]. Study of nuclei near stability as fission fragments following heavy-ion reactions / N. Fotiadis. [symbol]C and [symbol]N: lifetime measurements of their first-excited states / M. Wiedeking ... [et al.] -- Nuclear astrophysics. Isomer spectroscopy near [symbol]Sn - first observation of excited states in [symbol]Cd / M. Pfitzner ... [et al.]. Nuclear masses and what they imply for the structures of neutron rich nuclei / A. Awahamian and A. Teymurazyan. Multiple nucleosynthesis processes in the early universe / F. Montes. Single-neutron structure of neutron-rich nuclei near N = 50 and N = 82 / J. A. Cizewski ... [et al.]. [symbol]Cadmium: ugly duckling or young swan / W. B. Walters ... [et al.] -- Nuclear structure V. Evidence for chiral doublet bands in [symbol]Ru / Y. X. Luo ... [et al.]. Unusual octupole shape deformation terms and K-mixing / J. O. Rasmussen ... [et al.]. Spin assignments, mixing ratios, and g-factors in neutron rich [symbol]Cf fission products / C. Goodin ... [et al.]. Level structures and double [symbol]-bands in [symbol]Mo, [symbol]Mo and [symbol]Ru / S. J. Zhu ... [et al.] -- Nuclear theory. Microscopic dynamics of shape coexistence phenomena around [symbol]Se and [symbol]Kr / N. Hinohara ... [et al.]. Nuclear structure, double beta decay and test of physics beyond the standard model / A. Faessler. Collective modes in elastic nuclear matter / Ş. Mişicu and S. Bastrukov. From N = Z to neutron rich: magnetic moments of Cu isotopes at and above the [symbol]Ni and [symbol]Ni double shell closures - what next? / N. J. Stone, J. R. Stone and U. Köster -- Nuclear structure VI. Decay studies of nuclei near [symbol]Ni / R. Grzywacz. Weakening of the [symbol]Ni core for Z > 28, N > 50? / J. A. Winger ... [et al.]. Coulomb excitation of the odd-A [symbol]Cu isotopes with MINIBALL and REX-ISOLDE / I. Stefanescu ... [et al.]. Neutron single particle states and isomers in odd mass nickel isotopes near [symbol]Ni / M. M. Raiabali ... [et al.]. [symbol] and [symbol]-delayed neutron decay studies of [symbol]Ch at the HRIBF / S. V. Ilvushkin ... [et al.] -- Posters. Properties of Fe, Ni and Zn isotope chains near the drip-line / V. N. Tarasov ... [et al.]. Probing nuclear structure of [symbol]Xe / J. B. Gupta. Shape coexistence in [symbol]Zr and large deformation in [symbol]Zr / J. K. Hwang ... [et al.]. Digital electronics and their application to beta decay spectroscopy / S. N. Liddick, S. Padgett and R. Grzywacz. Nuclear shape and structure in neutron-rich [symbol]Tc / Y. X. Luo ... [et al.]. Speeding up the r-process. Investigation of first forbidden [symbol] decays in N > 50 isotopes near [symbol]Ni / S. Padgett ... [et al.]. Yields of fission products from various actinide targets / E. H. Sveiewski ... [et al.].

Improved segmentation of abnormal cervical nuclei using a graph-search based approach

NASA Astrophysics Data System (ADS)

Zhang, Ling; Liu, Shaoxiong; Wang, Tianfu; Chen, Siping; Sonka, Milan

2015-03-01

Reliable segmentation of abnormal nuclei in cervical cytology is of paramount importance in automation-assisted screening techniques. This paper presents a general method for improving the segmentation of abnormal nuclei using a graph-search based approach. More specifically, the proposed method focuses on the improvement of coarse (initial) segmentation. The improvement relies on a transform that maps round-like border in the Cartesian coordinate system into lines in the polar coordinate system. The costs consisting of nucleus-specific edge and region information are assigned to the nodes. The globally optimal path in the constructed graph is then identified by dynamic programming. We have tested the proposed method on abnormal nuclei from two cervical cell image datasets, Herlev and H and E stained liquid-based cytology (HELBC), and the comparative experiments with recent state-of-the-art approaches demonstrate the superior performance of the proposed method.

Two-neutron decay within RMF+BCS approach

NASA Astrophysics Data System (ADS)

Kumawat, M.; Singh, U. K.; Saxena, G.; Kaushik, M.; Jain, S. K.

2018-05-01

A theoretical global study has been done for identifying possible candidates of 2n-radioactivity for all even and odd nuclei under proton number Z ≤ 40 by employing Relativistic Mean-Filed plus BCS (RMF+BCS) approach. We investigate two-and one-neutron separation energy, deformation, pairing energy, wave-function, potential and other ground state properties for our study of even and odd Z nuclei to find candidates of 2n-decay within Z ≤ 40. These results are found in agreement of recent experiments and consistent with other parameters of RMF and other theories.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moller, Peter; Pereira, J; Hennrich, S

Measurements of the {beta}-decay properties of A {approx}< 110 r-process nuclei have been completed at the National Superconducting Cyclotron Laboratory, at Michigan State University. {beta}-decay half-lives for {sup 105}Y, {sup 106,107}Zr and {sup 108,111}Mo, along with ,B-delayed neutron emission probabilities of 104Y, 109,11OMo and upper limits for 105Y, 103-107Zr and 108,111 Mo have been measured for the first time. Studies on the basis of the quasi-random phase approximation are used to analyze the ground-state deformation of these nuclei.

Residual Stresses and Sliding Wear.

DTIC Science & Technology

1982-05-25

case of rolling contact, taking into account strain hardening during plastic deformation. ..-s calculations (forSAE 52100 at a hardness level of 58.5 R...can reach -800- 1000 MPa. If 033 was comparable to these values, it would indeed effect the wear rate. It is evident that an experimental deter...cc o 40 1 °2 00 I I +A ) S l~lll0 44MUK I CQ E3 e0 El 0 Uc 00 E3 (3 80 j40 c (vclq) SSHHI +ce ce mCQ ce (2E e0 4El EJ) E - 0 El 0 E0 .. t El 0 (vdNp

Neutrino-Induced Nucleosynthesis in Helium Shells of Early Core-Collapse Supernovae

NASA Astrophysics Data System (ADS)

Banerjee, Projjwal; Qian, Yong-Zhong; Heger, Alexander; Haxton, Wick

2016-02-01

We summarize our studies on neutrino-driven nucleosynthesis in He shells of early core-collapse supernovae with metallicities of Z ≲ 10-3 Z⊙. We find that for progenitors of ˜ 11-15 M⊙, the neutrons released by 4He(ν¯ee, e+n)3H in He shells can be captured to produce nuclei with mass numbers up to A ˜ 200. This mechanism is sensitive to neutrino emission spectra and flavor oscillations. In addition, we find two new primary mechanisms for neutrino-induced production of 9Be in He shells. The first mechanism produces 9Be via 7Li(n,γ)8Li(n,γ)9Li(e- ν¯ee)9Be and relies on a low explosion energy for its survival. The second mechanism operates in progenitors of ˜ 8 M⊙, where 9Be can be produced directly via 7Li(3H, n0)9Be during the rapid expansion of the shocked Heshell material. The light nuclei 7Li and 3H involved in these mechanisms are produced by neutrino interactions with 4He. We discuss the implications of neutrino-induced nucleosynthesis in He shells for interpreting the elemental abundances in metal-poor stars.

Microgravity in the STS-29 space shuttle discovery affected the vestibular system of chick embryos

NASA Technical Reports Server (NTRS)

Fermin, C. D.; Martin, D.; Jones, T.; Vellinger, J.; Deuser, M.; Hester, P.; Hullinger, R.

1996-01-01

Out of 32 embryos flown (16 @ E2 + 16 @ E9) for 5 days, 16 survived. All sixteen E2 were dead at landing. Eight were opened and eight were incubated at 1.0G. Autopsy showed that 4 E2 survived over 24 hours in space. Eight E14 hatched without anatomical malformations, and 8 E14 were fixed. The height of the macular epithelia was 31 mu m (mean) in control and 26 mu m in flight chicks. The cross-sectional area of macular nuclei of control was 17 mu m(2) for hair cells and 14 mu m(2) in supporting cells. In flight, cross-sectional area was 17 mu m(2) in hair cells and 15 mu m(2) in supporting cells (n=250). The shape factor of cartilage cells (1.0 = perfect circle) between control (mean = 0.70) and flight (mean = 0.72), and the area of cartilaginous cells between controls (mean = 9 mu m(2)) and flight (mean = 9 mu m(2)) did not differ (n=300). The nuclei of support cells were closer to the basement membrane in flight than in control chicks. The immunoreactivity of otoconia with anti keratan, fibronectin or chrondroitin sulfate was not different between flight and control ears. There were more afferent fibers inside the macular epithelia of flight (p<0.05) than control. Three of 8 flight animals had elevated vestibular thresholds (VT), with normal mean response amplitudes and latencies. Modified afferent innervation patterns requiring weeks to compensate are sufficient to elevate VT, and should be investigated further. Other reversible (sublethal) microgravity effects on sensory epithelia (vacuoles, swelling, etc) require quantification.

Mutagenic assessment of Lithobates catesbeianus tadpoles exposed to the 2,4-D herbicide in a simulated realistic scenario.

PubMed

Mesak, Carlos; de Oliveira Mendes, Bruna; de Oliveira Ferreira, Raíssa; Malafaia, Guilherme

2018-05-01

The aim of the current study is to assess possible erythrocyte mutagenic effects on Lithobates catesbeianus tadpoles exposed to water contaminated with 2,4-D. In order to do so, tadpoles were exposed to a predictive and environmentally relevant herbicide concentration (1.97 mg/L), which is likely to be found in lentic environments formed by superficial water runoffs in pasture areas where the herbicide was applied. The micronucleus test, as well as tests for other nuclear abnormalities, was conducted after 3, 5, and 9 days of exposure (d.e.). Changes in the biomass and mouth-cloaca length or interference in the larval development of the animals (in the three evaluated times) were not recorded. However, tadpoles exposed to 2,4-D showed the highest total number of nuclear abnormalities, as well as the highest frequency of binucleated erythrocytes and kidney-shaped nuclei (shortly after 3 d.e.). The micronucleus frequency was also higher in animals exposed to 2,4-D (in the 3rd, 5th, and 9th d.e.), as well as the frequency of binucleated cells (3rd, 5th, and 9th d.e.) presenting notched (9th d.e.) and blebbled (9th d.e.) nuclei in comparison to those of the control, after 5 and 9 days of exposure. Therefore, the current study is a pioneer in showing that 2,4-D has a mutagenic effect on L. catesbeianus tadpoles, even at low concentrations (environmentally relevant) and for a short period of time, a fact that may lead to direct losses in anuran populations living in areas adjacent to those subjected to 2,4-D herbicide application.

PROCEEDINGS: ADVANCES IN PARTICLE SAMPLING AND MEASUREMENT (ASHEVILLE, NC, MAY 1978)

EPA Science Inventory

The proceedings consist of 17 papers on improved instruments and techniques for sampling and measuring particulate emissions and aerosols; e.g., cascade impactors, cyclone collectors, and diffusion-battery/nuclei-counter combinations. Transmissometers and instruments for measurin...

Molecular and behavioral profiling of Dbx1-derived neurons in the arcuate, lateral and ventromedial hypothalamic nuclei.

PubMed

Sokolowski, Katie; Tran, Tuyen; Esumi, Shigeyuki; Kamal, Yasmin; Oboti, Livio; Lischinsky, Julieta; Goodrich, Meredith; Lam, Andrew; Carter, Margaret; Nakagawa, Yasushi; Corbin, Joshua G

2016-05-21

Neurons in the hypothalamus function to regulate the state of the animal during both learned and innate behaviors, and alterations in hypothalamic development may contribute to pathological conditions such as anxiety, depression or obesity. Despite many studies of hypothalamic development and function, the link between embryonic development and innate behaviors remains unexplored. Here, focusing on the embryonically expressed homeodomain-containing gene Developing Brain Homeobox 1 (Dbx1), we explored the relationship between embryonic lineage, post-natal neuronal identity and lineage-specific responses to innate cues. We found that Dbx1 is widely expressed across multiple developing hypothalamic subdomains. Using standard and inducible fate-mapping to trace the Dbx1-derived neurons, we identified their contribution to specific neuronal subtypes across hypothalamic nuclei and further mapped their activation patterns in response to a series of well-defined innate behaviors. Dbx1-derived neurons occupy multiple postnatal hypothalamic nuclei including the lateral hypothalamus (LH), arcuate nucleus (Arc) and the ventral medial hypothalamus (VMH). Within these nuclei, Dbx1 (+) progenitors generate a large proportion of the Pmch-, Nesfatin-, Cart-, Hcrt-, Agrp- and ERα-expressing neuronal populations, and to a lesser extent the Pomc-, TH- and Aromatase-expressing populations. Inducible fate-mapping reveals distinct temporal windows for development of the Dbx1-derived LH and Arc populations, with Agrp(+) and Cart(+) populations in the Arc arising early (E7.5-E9.5), while Pmch(+) and Hcrt(+) populations in the LH derived from progenitors expressing Dbx1 later (E9.5-E11.5). Moreover, as revealed by c-Fos labeling, Dbx1-derived cells in male and female LH, Arc and VMH are responsive during mating and aggression. In contrast, Dbx1-lineage cells in the Arc and LH have a broader behavioral tuning, which includes responding to fasting and predator odor cues. We define a novel fate map of the hypothalamus with respect to Dbx1 expression in hypothalamic progenitor zones. We demonstrate that in a temporally regulated manner, Dbx1-derived neurons contribute to molecularly distinct neuronal populations in the LH, Arc and VMH that have been implicated in a variety of hypothalamic-driven behaviors. Consistent with this, Dbx1-derived neurons in the LH, Arc and VMH are activated during stress and other innate behavioral responses, implicating their involvement in these diverse behaviors.

Proton-neutron sdg boson model and spherical-deformed phase transition

NASA Astrophysics Data System (ADS)

Otsuka, Takaharu; Sugita, Michiaki

1988-12-01

The spherical-deformed phase transition in nuclei is described in terms of the proton-neutron sdg interacting boson model. The sdg hamiltonian is introduced to model the pairing+quadrupole interaction. The phase transition is reproduced in this framework as a function of the boson number in the Sm isotopes, while all parameters in the hamiltonian are kept constant at values reasonable from the shell-model point of view. The sd IBM is derived from this model through the renormalization of g-boson effects.

M1 excitation in Sm isotopes and the proton-neutron sdg interacting boson model

NASA Astrophysics Data System (ADS)

Mizusaki, Takahiro; Otsuka, Takaharu; Sugita, Michiaki

1991-10-01

The magnetic-dipole scissors mode in spherical to deformed Sm isotopes is studied in terms of the proton-neutron sdg interacting boson model, providing a good agreement with recent experiment by Ziegler et al. The present calculation correctly reproduces the increase of M1 excitation strength in going from spherical to deformed nuclei. It is suggested that there may be 1+ states which do not correspond to the scissors mode but absorb certain M1 strength from the ground state.

Thin-skinned tectonics in the Central Basin of the Iranian Plateau in the Semnan area, Central Iran

NASA Astrophysics Data System (ADS)

Bouzari, Soheila; Konon, Andrzej; Koprianiuk, Marek; Julapour, Ali A.

2013-01-01

During continent-continent convergence of the Arabian and Eurasian plates, and after the late Eocene inversion of a back-arc rift, the Iranian Plateau underwent broad subsidence resulting in the formation of the Central Basin (Morley et al., 2009). New 2D seismic data acquired by National Iranian Oil Company (NIOC) in the NW-SW-trending arm of the Central Basin suggest that during the main stage of shortening (middle-late? Miocene to Pliocene), strain concentrations resulted in the development of the thin-skinned Kuh-e-Gachab, Kuh-e-Gugerd, Garmsar and Sorkh-e-Kuh structures. These structures are built of Oligocene-Miocene/Pliocene(?) rocks belonging to the Lower Red, Qom and Upper Red formations. Seismic data suggest that one of these structures comprises the south-verging Kuh-e-Gachab anticline, which is bounded by the N-dipping Kuh-e-Gachab thrust and cored by a complex array of thrust sheets forming a triangle zone. During the deformation process, two salt evaporate levels played a significant role as detachment horizons. The main detachment horizon was rooted within the Lower Red Formation, whereas the second detachment horizon was located along evaporites belonging to the Upper Red Formation. Variations in the thin-skinned style of deformation between the larger triangle zone in the western part of the Kuh-e-Gachab structure contrasts with less shortening in the smaller triangle zone to the east. This suggests that the change resulted from the increase of thickness of the mobile detachment horizon to the east. Contraction deformations are still active south of the Alborz Mountains, which is confirmed by GPS data and present-day seismicity.

NMR assignment of a PDZ domain in complex with a HPV51 E6 derived N-terminally pyroglutamic acid modified peptide.

PubMed

Mischo, André; Ohlenschläger, Oliver; Ramachandran, Ramadurai; Görlach, Matthias

2013-04-01

The resonance assignment of an amino-terminal pyroglutamic acid containing peptide derived from the E6 protein of human papillomavirus (HPV) type 51 in complex with PDZ domain 2 of hDlg/SAP-97 is reported. The assignments include (1)H, (13)C and (15)N resonances for the protein and peptide in the complex and all of the peptide's pyroglutamic acid nuclei.

High spin states in 162Lu

NASA Astrophysics Data System (ADS)

Gupta, S. L.; Pancholi, S. C.; Juneja, P.; Mehta, D.; Kumar, Ashok; Bhowmik, R. K.; Muralithar, S.; Rodrigues, G.; Singh, R. P.

1997-09-01

An experimental investigation of the odd-odd 162Lu nucleus, following the 148Sm(19F,5n) reaction at beam energy Elab=112 MeV, has been performed through in-beam gamma-ray spectroscopy. It revealed three signature-split bands. The yrast band based on πh11/2⊗νi13/2 configuration exhibits anomalous signature splitting (the unfavored signature Routhian lying lower than the favored one) whose magnitude Δe'~25 keV, is considerably reduced in contrast to sizable normal signature splitting Δe'~125 and 60 keV observed in the yrast πh11/2 bands of the neighboring odd-A 161,163Lu nuclei, respectively. The signature inversion in this band occurs at spin ~20ħ (frequency=0.37 MeV). The second signature-split band, observed above the band crossing associated with the alignment of a pair of i13/2 quasineutrons, is a band based on the four-quasiparticle [πh11/2[523]7/2-⊗νh9/2[521]3/2-⊗(νi13/2)2], i.e., EABAp(Bp), configuration. The third signature-split band is also likely to be a four-quasiparticle band with configuration similar to the second band but involving F quasineutron, i.e., FABAp(Bp). The experimental results are discussed in comparison with the existing data in the neighboring nuclei and in the framework of the cranking shell model.

Micro-analyses of Interplanetary Dust Particles (IDPs) and Micrometeorites (MMs): Implications for sample return missions to undifferentiated protoplanets

NASA Astrophysics Data System (ADS)

Rietmeijer, F.

The good news is that the original, typically non-chondritic, presolar dust had an extremely simple mineralogy of predominantly Mg-rich olivines and -pyroxenes, pyrrhotite (Fe7 S8 ), Fe-o xides and Fe,Ni-metal. This unique property is preserved in the least modified protoplanets for in situ sampling (e.g. STARDUST, MUSES-C) and in their debris in the form of stratospheric IDPs and MMs. The corollary is that mineralogical complexity in all extraterrestrial materials is an evolved secondary property. The earliest stages of solar system evolution were defined by hierarchical dust accretion whereby the accreting dust was recycled prior to the formation of the final surviving protoplanets. This recycling concentrated initially minor elements so they could form new minerals , e.g. alkali-feldspars and plagioclase. The least- modified protoplanets are comet nuclei, i.e. random mixtures of rubble piles and dirty snowballs, and the icy (ultra)carbonaceous asteroids. Second best are the dormant, extinct and rare active comet nuclei among the near-Earth asteroids that are relatively easy to access by sample return missions. Third are the anhydrous CO/CV carbonaceous chondrites and the low metamorphic grade, unequilibrated ordinary chondrites from the main asteroid belt. Lithification of the original rubble piles in these asteroids erased all structural properties but not the mineralogy and chemistry of the accreted entities, i.e. matrix, chondrules and CAIs.Consequently , returned samples of small chips, fragments or powders from the surface of undifferentiated protoplanets will amply suffice for a full mineralogical and chemical characterization of these small bodies, including modifications from interactions with the space environment, e.g. space weathering, regolith formation and the black mantle on icy-protoplanets. Major improvements in the sensitivity of available micro-analytical tools means that in situ acquired samples can be analyzed at scales of individual, n m-s i z e d constituents to determine the major rock-forming and minor element abundances , isotopic compositions, the nature of and chemical bonds in organic matter. The nature of solid s , crystalline or amorphous, can be identified and the solid-state modification as a function of composition. Measurements of noble gas abundances and isotopes and the physical properties (e.g. density) require samples of only a few nano-grams. Sample site selection on rubble piles is critical. For example, boulders and pebbles in comet nuclei might be proto- CI material that is the most pristine, anhydrous lithified rock in the solar system.

Cosmic mass spectrometer

NASA Astrophysics Data System (ADS)

Anchordoqui, Luis A.; Barger, Vernon; Weiler, Thomas J.

2018-03-01

We argue that if ultrahigh-energy (E ≳1010GeV) cosmic rays are heavy nuclei (as indicated by existing data), then the pointing of cosmic rays to their nearest extragalactic sources is expected for 1010.6 ≲ E /GeV ≲1011. This is because for a nucleus of charge Ze and baryon number A, the bending of the cosmic ray decreases as Z / E with rising energy, so that pointing to nearby sources becomes possible in this particular energy range. In addition, the maximum energy of acceleration capability of the sources grows linearly in Z, while the energy loss per distance traveled decreases with increasing A. Each of these two points tend to favor heavy nuclei at the highest energies. The traditional bi-dimensional analyses, which simultaneously reproduce Auger data on the spectrum and nuclear composition, may not be capable of incorporating the relative importance of all these phenomena. In this paper we propose a multi-dimensional reconstruction of the individual emission spectra (in E, direction, and cross-correlation with nearby putative sources) to study the hypothesis that primaries are heavy nuclei subject to GZK photo-disintegration, and to determine the nature of the extragalactic sources. More specifically, we propose to combine information on nuclear composition and arrival direction to associate a potential clustering of events with a 3-dimensional position in the sky. Actually, both the source distance and maximum emission energy can be obtained through a multi-parameter likelihood analysis to accommodate the observed nuclear composition of each individual event in the cluster. We show that one can track the level of GZK interactions on an statistical basis by comparing the maximum energy at the source of each cluster. We also show that nucleus-emitting-sources exhibit a cepa stratis structure on Earth which could be pealed off by future space-missions, such as POEMMA. Finally, we demonstrate that metal-rich starburst galaxies are highly-plausible candidate sources, and we use them as an explicit example of our proposed multi-dimensional analysis.

Velocity of Ejection of Meteor Particle from the Nucleus of Comets

NASA Astrophysics Data System (ADS)

Safarov, Abduljalol; Ibadinov, Khursand

2016-07-01

The time and velocity of dust particles of anomalous tail of comets was determine. Velocity ejection of dust particles from the nuclei of comets C/1851 U1, C/1877 G1, C/1921 E1, C/1925 V1, C/1962 C1, C/1969 T1, C/1975 V2, 2P/1924 and 26P/1927 F1 reaching up to 0.4 km/s can be attributed to the removal of large dust particles from the surface of the icy nucleus of comet sublimating molecules. In comets C/1823 Y1, C/1844 Y1, C/1882 R1, C/1883 D1, C/1888 R1, C/1892 E1, D/1894 F1, C/1910 A1, C/1921 E1, C/1922 U1, C/1930 D1, C/1930 O1, C/1931 P1, C/1932 M1, C/1935 A1, C/1954 O1, C/1961 O1, C/1963 A1, C/1968 H1, C/1973 E1, C/1980 P1, C/1984 N2, C/1987 P1, C/1995 O1, C/1999 H1, C/1999 T2, C/1999 S4, C/2002 T7, C/2004 F4, C/2004 Q2, 6P/1950, 7P/1869 G1, 7P/1933, 10P/1930, 19P/1918, 34P/1938 J1, 35P/1939, 67P/1982, 73P/1930 J1, 96P/1986 J1 and 109P/1862 O1 ejection velocity (up to a few km/s) of the particles of anomalous tail from the nuclei significantly exceed the thermal velocity of the molecules sublimating ice nuclei. Such velocity may be explained by the removal of particles from the surface of the nucleus after the collision of the comet nucleus with meteoroids

Chaos in nuclei: Theory and experiment

NASA Astrophysics Data System (ADS)

Muñoz, L.; Molina, R. A.; Gómez, J. M. G.

2018-05-01

During the last three decades the quest for chaos in nuclei has been quite intensive, both with theoretical calculations using nuclear models and with detailed analyses of experimental data. In this paper we outline the concept and characteristics of quantum chaos in two different approaches, the random matrix theory fluctuations and the time series fluctuations. Then we discuss the theoretical and experimental evidence of chaos in nuclei. Theoretical calculations, especially shell-model calculations, have shown a strongly chaotic behavior of bound states in regions of high level density. The analysis of experimental data has shown a strongly chaotic behavior of nuclear resonances just above the one-nucleon emission threshold. For bound states, combining experimental data of a large number of nuclei, a tendency towards chaotic motion is observed in spherical nuclei, while deformed nuclei exhibit a more regular behavior associated to the collective motion. On the other hand, it had never been possible to observe chaos in the experimental bound energy levels of any single nucleus. However, the complete experimental spectrum of the first 151 states up to excitation energies of 6.20 MeV in the 208Pb nucleus have been recently identified and the analysis of its spectral fluctuations clearly shows the existence of chaotic motion.

Non-classical continuum theory for solids incorporating internal rotations and rotations of Cosserat theories

NASA Astrophysics Data System (ADS)

Surana, K. S.; Joy, A. D.; Reddy, J. N.

2017-03-01

This paper presents a non-classical continuum theory in Lagrangian description for solids in which the conservation and the balance laws are derived by incorporating both the internal rotations arising from the Jacobian of deformation and the rotations of Cosserat theories at a material point. In particular, in this non-classical continuum theory, we have (i) the usual displacements ( ±b \\varvec{u}) and (ii) three internal rotations ({}_i ±b \\varvec{Θ}) about the axes of a triad whose axes are parallel to the x-frame arising from the Jacobian of deformation (which are completely defined by the skew-symmetric part of the Jacobian of deformation), and (iii) three additional rotations ({}_e ±b \\varvec{Θ}) about the axes of the same triad located at each material point as additional three degrees of freedom referred to as Cosserat rotations. This gives rise to ±b \\varvec{u} and {}_e ±b \\varvec{{Θ} as six degrees of freedom at a material point. The internal rotations ({}_i ±b \\varvec{Θ}), often neglected in classical continuum mechanics, exist in all deforming solid continua as these are due to Jacobian of deformation. When the internal rotations {}_i ±b \\varvec{Θ} are resisted by the deforming matter, conjugate moment tensor arises that together with {}_i ±b \\varvec{Θ} may result in energy storage and/or dissipation, which must be accounted for in the conservation and the balance laws. The Cosserat rotations {}_e ±b \\varvec{Θ} also result in conjugate moment tensor which, together with {}_e ±b \\varvec{Θ}, may also result in energy storage and/or dissipation. The main focus of the paper is a consistent derivation of conservation and balance laws that incorporate aforementioned physics and associated constitutive theories for thermoelastic solids. The mathematical model derived here has closure, and the constitutive theories derived using two alternate approaches are in agreement with each other as well as with the condition resulting from the entropy inequality. Material coefficients introduced in the constitutive theories are clearly defined and discussed.

Multiscale Modeling of Deformation Twinning Based on Field Theory of Multiscale Plasticity (FTMP)

DTIC Science & Technology

2013-09-01

of the deformation twinning: nucleation, growth (into, e.g., lenticular shapes), lattice rotation (satisfying the mirror symmetry), the attendant...Nucleation and subsequent growth into lenticular shapes is realistically captured. • Stress-strain responses accompanied by serration and overall softening

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Yoonyoung; Ishiguro, Masateru; Usui, Fumihiko

We investigated the population of asteroids in comet-like orbits using available asteroid size and albedo catalogs of data taken with the Infrared Astronomical Satellite, AKARI, and the Wide-field Infrared Survey Explorer on the basis of their orbital properties (i.e., the Tisserand parameter with respect to Jupiter, T{sub J}, and the aphelion distance, Q). We found that (1) there are 123 asteroids in comet-like orbits by our criteria (i.e., Q > 4.5 AU and T{sub J} < 3), (2) 80% of them have low albedo, p{sub v} < 0.1, consistent with comet nuclei, (3) the low-albedo objects among them have amore » size distribution shallower than that of active comet nuclei, that is, the power index of the cumulative size distribution is around 1.1, and (4) unexpectedly, a considerable number (i.e., 25 by our criteria) of asteroids in comet-like orbits have high albedo, p{sub v} > 0.1. We noticed that such high-albedo objects mostly consist of small (D < 3 km) bodies distributed in near-Earth space (with perihelion distance of q < 1.3 AU). We suggest that such high-albedo, small objects were susceptible to the Yarkovsky effect and drifted into comet-like orbits via chaotic resonances with planets.« less

Cannabinoid type-1 receptor signaling in central serotonergic neurons regulates anxiety-like behavior and sociability

PubMed Central

Häring, Martin; Enk, Vanessa; Aparisi Rey, Alejandro; Loch, Sebastian; Ruiz de Azua, Inigo; Weber, Tillmann; Bartsch, Dusan; Monory, Krisztina; Lutz, Beat

2015-01-01

The endocannabinoid (eCB) system possesses neuromodulatory functions by influencing the release of various neurotransmitters, including γ-aminobutyric acid (GABA) and glutamate. A functional interaction between eCBs and the serotonergic system has already been suggested. Previously, we showed that cannabinoid type-1 (CB1) receptor mRNA and protein are localized in serotonergic neurons of the raphe nuclei, implying that the eCB system can modulate serotonergic functions. In order to substantiate the physiological role of the CB1 receptor in serotonergic neurons of the raphe nuclei, we generated serotonergic 5-hydroxytryptamine (5-HT) neuron-specific CB1 receptor-deficient mice, using the Cre/loxP system with a tamoxifen-inducible Cre recombinase under the control of the regulatory sequences of the tryptophan hydroxylase 2 gene (TPH2-CreERT2), thus, restricting the recombination to 5-HT neurons of the central nervous system (CNS). Applying several different behavioral paradigms, we revealed that mice lacking the CB1 receptor in serotonergic neurons are more anxious and less sociable than control littermates. Thus, we were able to show that functional CB1 receptor signaling in central serotonergic neurons modulates distinct behaviors in mice. PMID:26388750

Reward deficiency and anti-reward in pain chronification.

PubMed

Borsook, D; Linnman, C; Faria, V; Strassman, A M; Becerra, L; Elman, I

2016-09-01

Converging lines of evidence suggest that the pathophysiology of pain is mediated to a substantial degree via allostatic neuroadaptations in reward- and stress-related brain circuits. Thus, reward deficiency (RD) represents a within-system neuroadaptation to pain-induced protracted activation of the reward circuits that leads to depletion-like hypodopaminergia, clinically manifested anhedonia, and diminished motivation for natural reinforcers. Anti-reward (AR) conversely pertains to a between-systems neuroadaptation involving over-recruitment of key limbic structures (e.g., the central and basolateral amygdala nuclei, the bed nucleus of the stria terminalis, the lateral tegmental noradrenergic nuclei of the brain stem, the hippocampus and the habenula) responsible for massive outpouring of stressogenic neurochemicals (e.g., norepinephrine, corticotropin releasing factor, vasopressin, hypocretin, and substance P) giving rise to such negative affective states as anxiety, fear and depression. We propose here the Combined Reward deficiency and Anti-reward Model (CReAM), in which biopsychosocial variables modulating brain reward, motivation and stress functions can interact in a 'downward spiral' fashion to exacerbate the intensity, chronicity and comorbidities of chronic pain syndromes (i.e., pain chronification). Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Estimation of M 1 scissors mode strength for deformed nuclei in the medium- to heavy-mass region by statistical Hauser-Feshbach model calculations

DOE PAGES

Mumpower, Matthew Ryan; Kawano, Toshihiko; Ullmann, John Leonard; ...

2017-08-17

Radiative neutron capture is an important nuclear reaction whose accurate description is needed for many applications ranging from nuclear technology to nuclear astrophysics. The description of such a process relies on the Hauser-Feshbach theory which requires the nuclear optical potential, level density, and γ-strength function as model inputs. It has recently been suggested that the M1 scissors mode may explain discrepancies between theoretical calculations and evaluated data. We explore statistical model calculations with the strength of the M1 scissors mode estimated to be dependent on the nuclear deformation of the compound system. We show that the form of the M1more » scissors mode improves the theoretical description of evaluated data and the match to experiment in both the fission product and actinide regions. Since the scissors mode occurs in the range of a few keV to a few MeV, it may also impact the neutron capture cross sections of neutron-rich nuclei that participate in the rapid neutron capture process of nucleosynthesis. As a result, we comment on the possible impact to nucleosynthesis by evaluating neutron capture rates for neutron-rich nuclei with the M1 scissors mode active.« less

Kinematic Model for the Sierra Nevada Frontal Fault Zone, California: Paleomagnetism of the Eureka Valley Tuff

NASA Astrophysics Data System (ADS)

Rood, D. H.; Burbank, D. W.; Luyendyk, B. P.

2005-12-01

We document the geometry, timing, rates, and kinematic style of Late Tertiary deformation between Sonora Pass and Mono Basin, central Sierra Nevada, California. Observed mismatches between geodetic and geologic deformation rates in the western Great Basin may be primarily due to underestimates of true geologic deformation. Relatively little attention has been paid to the role of permanent deformation between faults, i.e. folding or crustal block rotation. Current slip discrepancies may be accounted for if a significant component of off-fault transrotational deformation is present. We use geologic and paleomagnetic data to address the kinematic development of the Sierra Nevada frontal fault zone (SNFFZ), and to quantify both the elastic and inelastic strain accumulated across the Sierra Nevada-Basin and Range transition since ~9 Ma. The complex structure of this transition, between the regions of Sonora Pass and Mono Basin, may be a result of three distinct modes of dextral shear accommodation (transtensional, transpressional, and crustal thinning). The study area is characterized by four important structural elements that lie between the SNFFZ and Walker Lane Belt: (1) N- to NNW-striking normal and oblique faults, dominantly E-dipping, and associated W-tilted fault blocks; (2) NW-striking dextral faults; (3) ENE- to NE-striking left-lateral oblique faults that may accommodate overall dextral shear through clockwise vertical axis rotations of fault blocks; (4) E- to NE-trending folds, which may accommodate N-S shortening at large-scale left steps in the dextral transtensional fault system. Between Bridgeport and Mono Basins, a regional E- to NE-trending fold is present that affects both the Tertiary volcanic strata and a Quaternary glacial outwash surface. To the west, normal faulting rates on the SNFFZ are 1-2 mm/yr (Bursik and Sieh, 1989). This slip decreases to the north, into the folded region of the Bodie Hills. This kinematic relationship suggests that the region may be an accommodation zone between two linking faults, possibly an active fold that accommodates N-S shortening at a large-scale left step in the range front fault system. We collected ~200 paleomagnetic samples from the Late Miocene Eureka Valley Tuff of the Stanislaus Group at 21 sites over a 125-km-long, E-W transect (from the Sierra Nevada foothills to east of Mono Basin). Stepwise AF demagnetization reveals a stable characteristic remnant magnetization. Our preliminary data suggest 20-40 degrees of clockwise rotation adjacent to faults of the SNFFZ. An expanded dataset aims to identify specific structural domains, quantify differential vertical axis block rotations, and test geometric models of transrotation (i.e. block-specific versus gradational) during transtensional lithospheric deformation.

Properties of true quaternary fission of nuclei with allowance for its multistep and sequential character

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kadmensky, S. G., E-mail: kadmensky@phys.vsu.ru; Titova, L. V.; Bulychev, A. O.

An analysis of basicmechanisms of binary and ternary fission of nuclei led to the conclusion that true ternary and quaternary fission of nuclei has a sequential two-step (three-step) character, where, at the first step, a fissile nucleus emits a third light particle (third and fourth light particles) under shakeup effects associated with a nonadiabatic character of its collective deformation motion, whereupon the residual nucleus undergoes fission to two fission fragments. Owing to this, the formulas derived earlier for the widths with respect to sequential two- and three-step decays of nuclei in constructing the theory of two-step twoproton decays and multistepmore » decays in chains of genetically related nuclei could be used to describe the relative yields and angular and energy distributions of third and fourth light particles emitted in (α, α), (t, t), and (α, t) pairs upon the true quaternary spontaneous fission of {sup 252}Cf and thermal-neutron-induced fission of {sup 235}U and {sup 233}U target nuclei. Mechanisms that explain a sharp decrease in the yield of particles appearing second in time and entering into the composition of light-particle pairs that originate from true quaternary fission of nuclei in relation to the yields of analogous particles in true ternary fission of nuclei are proposed.« less

Quasifree π0 and π- Electroproduction on 4He in the Δ-Resonance Region

NASA Astrophysics Data System (ADS)

Steenbakkers, M. F. M.; van Batenburg, M. F.; Bauer, Th. S.; Blok, H. P.; Botto, T.; Dodge, G. E.; Groep, D. L.; Heimberg, P.; Hesselink, W. H. A.; Higinbotham, D. W.; Jans, E.; Jun, Y.; Ketel, T. J.; Lapikás, L.; de Lange, D. J. J.; Norum, B. E.; Passchier, I.; Starink, R.; Todor, L.; de Vries, H.

2005-10-01

The reactions He4(e,e'pHe3)π- and He4(e,e'pHe3)π0 were studied simultaneously, and for the first time, in a large kinematical domain including the Δ-resonance region. This was achieved by detecting the recoiling He3 and H3 nuclei instead of the emitted pions. The dependences of the cross section on the recoil momentum prec, the invariant mass WπN, and the direction θπ,q' and ϕπ,q' of the produced pion, are globally well described by the results of (quasifree) distorted-wave impulse approximation calculations. However, in the Δ-resonance region there are clear discrepancies, which point to medium modifications of the Δ in He4.

MO-C-17A-08: Evaluation of Lung Deformation Using Three Dimensional Strain Maps

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cui, T; Huang, Q; Miller, W

2014-06-15

Purpose: To develop a systematic approach to generate three dimensional (3D) strain maps of lung using the displacement vector field (DVF) during the respiratory deformation, and to demonstrate its application in evaluating deformable image registration (DIR). Methods: A DVF based strain tensor at each voxel of interest (VOI) was calculated from the relative displacements between the VOI and each of the six nearest neighbors. The maximum and minimum stretches of a VOI can be determined by the principal strains (E{sub 1}, E{sub 2} and E{sub 3}), which are the eigenvalues and the corresponding strain tensors. Two healthy volunteers enrolled inmore » this study under IRB-approved protocol, each was scanned using 3D Hyperpolarized He-3 tagging-MRI and 3D proton-MRI with TrueFISP sequence at the endof- inhalation (EOI) and the end-of-exhalation (EOE) phases. 3D DVFs of tagging- and proton-MRI were obtained by the direct measurements of the tagging grid trajectory and by the DIR method implemented in commercial software. Results: 3D strain maps were successfully generated for all DVFs. The principal strain E1s were calculated as 0.43±0.05 and 0.17±0.25 for tagging-MRI and proton-MRI, respectively. The large values of E{sub 1} indicate the predominant lung motion in the superior-inferior (SI) direction. Given that the DVFs from the tagging images are considered as the ground truth, the discrepancies in the DIR-based strain maps suggest the inaccuracy of the DIR algorithm. In the E{sub 1} maps of tagging-MRI for subject 1, the fissures were distinguishable by the larger values (0.49±0.02) from the adjacent tissues (0.41±0.03) due to the larger relative displacement between the lung lobes. Conclusion: We have successfully developed a methodology to generate DVF-based 3D strain maps of lung. It can potentially enable us to better understand the pulmonary biomechanics and to evaluate and improve the DIR algorithms for the lung deformation. We are currently studying more subjects to evaluate this tool.« less

Neotectonic deformation in Tunisia (North of the African plate)

NASA Astrophysics Data System (ADS)

Soumaya, Abdelkader; Ben Ayed, Noureddine; Kadri, Ali; Delvaux, Damien; Khayati Ammar, Hayet; Braham, Ahmed

2017-04-01

In Tunisia, at the extreme North of the African plate, the neotectonic context is largely influenced by the Eurasia-Africa convergence. The aim of this work is to characterize the neotectonic regime that affected this region during Quaternary. Field work investigations integrated with published data allowed to evidence a spatial-temporal variation of the tectonic stress regime during this period. The spatial repartition of the different types of Quaternary to historical deformation shows a North-South neotectonic zoning in Tunisia. After lower Pleistocene, the Tellian domain (Maghrebides) in the North and its Atlassic foreland in central Tunisia are affected by NNW-SSE compression. It generated E-W to NE-SW folds and reverse faults, well developed in the Plio-Quaternary molassic basins of Kechabta and Jendouba (Northern Tunisia). In the Atlas, the major E-W and N-S pre-existing faults have been reactivated with dextral and sinistral strike-slip kinematic respectively, associated to en-echelon folds (Kasserine, N-S Axis, Northern Chott belt...). After the Tyrrhenian, a submeridian compressional regime affected Northern Tunisia (e.g., Bizerte region) and was responsible for the E-W folding of marine strata. More to the South, in the Tunisian Sahel, transtensional tectonics with a NW-SE horizontal maximal compression (SHmax) deformed the Tyrrhenian marine series (Khénis, Skanès, Monastir…). During the Holocene and up to present-day times, N-S compressional tectonics reactivated the E-W pre-existing faults with a reverse movement in Northern Tunisia (Bulla Regia, Utica …), generating historical earthquakes. In Central Tunisia, the Aqueduct of Cherichira (built around AD 850) is displaced by a N-S normal fault. Similarly, a mosaic of a roman house is shifted by 10 cm, along a N-S sinistral normal fault. These deformations evidence a transtensional tectonic regime. During the Quaternary, all the NW-SE oriented grabens are subsiding (e.g., Bizerte Lake, Grombalia, and others in central Atlas). They can be explained by the coexistence of extensional and compressional structures in a general compressional tectonic regime with NNW-SSE SHmax.

Global deformation of the Earth, surface mass anomalies, and the geodetic infrastructure required to study these processes

NASA Astrophysics Data System (ADS)

Kusche, J.; Rietbroek, R.; Gunter, B.; Mark-Willem, J.

2008-12-01

Global deformation of the Earth can be linked to loading caused by mass changes in the atmosphere, the ocean and the terrestrial hydrosphere. World-wide geodetic observation systems like GPS, e.g., the global IGS network, can be used to study the global deformation of the Earth directly and, when other effects are properly modeled, provide information regarding the surface loading mass (e.g., to derive geo-center motion estimates). Vice versa, other observing systems that monitor mass change, either through gravitational changes (GRACE) or through a combination of in-situ and modeled quantities (e.g., the atmosphere, ocean or hydrosphere), can provide indirect information on global deformation. In the framework of the German 'Mass transport and mass distribution' program, we estimate surface mass anomalies at spherical harmonic resolution up to degree and order 30 by linking three complementary data sets in a least squares approach. Our estimates include geo-center motion and the thickness of a spatially uniform layer on top of the ocean surface (that is otherwise estimated from surface fluxes, evaporation and precipitation, and river run-off) as a time-series. As with all current Earth observing systems, each dataset has its own limitations and do not realize homogeneous coverage over the globe. To assess the impact that these limitations might have on current and future deformation and loading mass solutions, a sensitivity study was conducted. Simulated real-case and idealized solutions were explored in which the spatial distribution and quality of GPS, GRACE and OBP data sets were varied. The results show that significant improvements, e.g., over the current GRACE monthly gravity fields, in particular at the low degrees, can be achieved when these solutions are combined with present day GPS and OBP products. Our idealized scenarios also provide quantitative implications on how much surface mass change estimates may improve in the future when improved observing systems become available.

The behaviour of monazite at high temperature and high stress in the lower crust

NASA Astrophysics Data System (ADS)

Clark, Chris; Taylor, Richard; Erickson, Timmons; Reddy, Steven; Fougerouse, Denis; Fitzsimons, Ian; Hand, Martin

2017-04-01

Monazite is fast becoming the go to geochronometer for establishing the timing of metamorphic, deformational and hydrothermal events in crustal rocks. This is principally due to monazite forming in rocks that are petrologically useful (e.g. metapelites), it's susceptibility to recrystallization (both fluid and deformation driven) and the suite of trace elements it incorporates during growth. In dry conditions (i.e. the melt-depleted lower crust) monazite has a high closure temperature. It therefore has the ability to record the timing of prograde to peak metamorphic conditions. The reactivity of monazite in the presence of fluid allows the timing of post-peak fluid and melt crystallisation events to be constrained. Under high-stress monazite will recrystallise, forming new crystals that can be used to constrain the age of deformational events - this feature is particularly useful as high-grade reworking of lower crustal rocks often leave no geochronological record within other accessory minerals (e.g. zircon). However, it has long been recognised that monazite can record a cryptic range and/or distribution of ages that are difficult reconcile with how we traditionally believe the lower crust responds to deformational events - e.g. the anhydrous nature of lower crustal rocks and the preservation of granulite facies mineral assemblages. Here we present datasets collected by a suite of microanalytical techniques on monazite grains from lower-crustal rocks that have experienced deformation, fluid-rock interaction and ultrahigh temperature metamorphism. To better understand how monazite behaves in these environments we integrate electron probe, electron backscatter diffraction, laser ablation split stream petrochronology, transmission electron microscopy and Atom Probe Tomography datasets to image and quantify behaviour of key elements from the micro- to the nanoscale. When used sequentially, these techniques provide a detailed view of the processes that re-distribute U-Th-REE-Y-Pb at the nanoscale. Understanding how monazite behaves under different stress and thermal conditions is the key to using this geochronometer to develop and refine event chronologies in the lower crust.

Quality of life of individuals with cleft lip and palate pre- and post-surgical correction of dentofacial deformity.

PubMed

Beluci, Marli Luiz; Genaro, Katia Flores

2016-04-01

To assesses the quality of life and the impact of oral health conditions in the pre- and post-surgical correction of dentofacial deformity of individuals with cleft lip and palate. Quantitative and prospective study in a referral hospital in the period from June 2011 to May 2013. A total of 50 participants responded the questionnaires World Health Organization Quality of Life - Bref (WHOQOL-Bref) and Oral Health Impact Profile - 14 (OHIP-14), approximately 3 days before and 3 to 12 months after surgery. The "t" test for paired samples and Wilcoxon test were used for statistical analysis with a significance level of 5%. After surgery, differences were found in the domains: Physical, Psychological, Environmental and General Questions of the WHOQOL-Bref and domains: Psychological Discomfort, Psychological Disability, Social Disability, Handicap and Overall Score of OHIP-14. Surgical correction of dentofacial deformity improved quality of life and had positive impact of oral health condition. Avaliar a qualidade de vida e o impacto das condições de saúde oral nos períodos pré e pós-correção cirúrgica da deformidade dentofacial de indivíduos com fissura labiopalatina operada. Estudo quantitativo e prospectivo, realizado em um hospital de referência, no período de junho de 2011 a maio de 2013. Participaram 50 indivíduos que responderam aos questionários World Health Organization Quality of Life - Bref (WHOQOL-Bref) e Oral Health Impact Profile - 14 (OHIP-14), aproximadamente 3 dias antes e entre 3 e 12 meses após a cirurgia. Os testes "t" para amostras pareadas e de Wilcoxon foram usados para análise estatística, com nível de significância de 5%. Após a cirurgia, foram encontradas diferenças nos domínios: Físico, Psicológico, Meio Ambiente e nas Questões Gerais do WHOQOL-Bref e nos domínios: Desconforto Psicológico, Limitação Psicológica, Limitação Social, Incapacidade e no Escore Geral do OHIP-14. A correção cirúrgica da deformidade dentofacial propiciou melhora da qualidade de vida e impacto positivo da condição da saúde oral.

Isomer spectroscopy using RI beam

NASA Astrophysics Data System (ADS)

Odahara, Atsuko

2009-10-01

We have studied systematically high-spin oblate shape isomers in the N=83 isotones, which have revealed the characteristics of nuclear structure, such as the preserving pairing interactions at high-spin states, decrease of Z=64 proton shell gap energy as the decrease of proton number from 64 to 60 and so on. Recently, it became possible to search for isomers by the secondary fusion reaction at high-spin states in nuclei, which could not be populated by the stable beam and stable target, using RCNP RI beam line at Osaka University. RI beams enable us to study high-spin states in nuclei in wide mass region. By using the RI beams delivered by RIBF and the high-efficiency γ-ray detection system GRETINA, it will be possible to investigate nuclei far from the stability line. Single-particle energies and nucleon-nucleon interactions of these nuclei close to drip line are expected to be the test ground of nuclear models, such as shell structures. We have a plan to search for isomers with half lives of ˜μsec to ˜msec and to explore the decay mechanism of isomers in the proton-rich nuclei along N=Z line with 80< A<100. Moreover we try to search for nuclei beyond the proton drip line, which could be defined that isomeric states would be bound by the centrifugal potential although the ground states would be unbound against the proton emission. Isomers are expected to reveal the following characteristics of these nuclei. (1) Existence of isomers could prove the magicity of N=Z=50 and the large neutron-proton interaction, as one of the candidates of isomers is spin-gap isomer which is caused by the lowering of excitation energies resulting from the stretch coupling of spins of high-j (g9/2) holes of the ^100Sn core. (2) Isomers could prove the nuclear deformation which is caused by the evolution of shell structure. One of spin-gap isomers in ^94Ag was reported to have large prolate deformation. (3) This mass region is on the way of the rapid proton (rp) synthesis pass. Recently, neutrino reactions in the super novae were reported to play a role of the synthesis of the rp-process nuclei. In the case of no path or slow down of rp process, isomers could contribute to synthesis of rp-nuclei with larger Z, although the production rates of isomers are small.

EMC effect: Past, Present, and Future

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fomin, Nadia

2015-09-01

Since the discovery of the EMC effect over 30 years ago, it has been of great theoretical interest and studied in several experimental measurements. No unified picture arose to explain the underlying cause of per nucleon structure function modification in nuclei. Precise measurements on light nuclei from JLab’s 6 GeV era revitalized this research by showing that traditional A or density dependent models of this nuclear modification do not work. The measurements will be reviewed, discussed and preliminary data on heavy targets from JLab’s E03-103 will be presented.

Astrophysics related programs at center for underground physics (CUP)

NASA Astrophysics Data System (ADS)

Kim, Yeongduk

2018-04-01

We are developing experimental programs related to particle astrophysics at the Center for Underground Physics (CUP); searching for neutrino-less double beta decay (0νββ) of 100Mo nuclei and sterile neutrinos in the mass range of eV using reactor neutrinos. Expected sensitivities of AMoRE double beta decay experiment and the results from recent NEOS experiment are described. Utilizing the facilities for ultra-low radioactivity measurement at the center, we are planning to measure the decay of 180mTa which is important to the nucleosynthesis of heavy nuclei.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ye, Zhihong

The experiment, E08-014, in Hall-A at Jefferson Lab aims to study the short-range correlations (SRC) which are necessary to explain the nuclear strength absent in the mean field theory. The cross sections for 2H, 3He, 4He, 12C, 40Ca and 48Ca, were measured via inclusive quasi-elastic electron scattering from these nuclei in a Q2 range between 0.8 and 2.8 (GeV/c) 2 for x>1. The cross section ratios of heavy nuclei to 2H were extracted to study two-nucleon SRC for 1

Mid-Infrared Properties of the Swift Burst Alert Telescope Active Galactic Nuclei Sample of the Local Universe. 1. Emission-Line Diagnostics

DTIC Science & Technology

2010-06-20

reserved. Printed in the U.S.A. MID-INFRARED PROPERTIES OF THE SWIFT BURST ALERT TELESCOPE ACTIVE GALACTIC NUCLEI SAMPLE OF THE LOCAL UNIVERSE . I. EMISSION... the AGNs. We also compare the mid-infrared emission lines in the BAT AGNs with those from published studies of ULIRGs, Palomar- Green quasars, star...supermassive black holes (e.g., Rees 1984; Peterson et al. 2004). One way to approach the study of AGNs is to concentrate on those in the local universe

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

NASA Astrophysics Data System (ADS)

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

2002-04-01

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

Neotectonic reactivation of the western section of the Malargüe fold and thrust belt (Tromen volcanic plateau, Southern Central Andes)

NASA Astrophysics Data System (ADS)

Sagripanti, Lucía; Rojas Vera, Emilio A.; Gianni, Guido M.; Folguera, Andrés; Harvey, Jonathan E.; Farías, Marcelo; Ramos, Victor A.

2015-03-01

This study examines the neotectonic deformation and development of the Tromen massif, a Quaternary retroarc volcanic field located in the western section of the Malargüe fold and thrust belt in the Southern Central Andes. The linkages between neotectonic deformation in the intra-arc zone and the recent retroarc structures of the Tromen volcanic plateau are not clearly understood. These retroarc deformations affect the mid-section of the fold and thrust belt, leaving to the east a 200 km-wide deformed zone that can be considered inactive over the last 12-10 Ma. This out-of-sequence deformation west of the orogenic front area has not been previously addressed in detail. In this study, exhaustive mapping is used to describe and discriminate structures with a neotectonic component from those fossilized by Pleistocene strata. Two balanced cross-sections are constructed showing the distribution of the youngest deformations and their relation to pre-Miocene structures. An important means for evaluating this is the morphometric and morphological analyses that allowed identification of perturbations in the fluvial network associated with active structures. In a broader perspective, neotectonic activity in the fold and thrust belt is discussed and inferred to be caused by local mechanical weakening of the retroarc zone, due to injection of asthenospheric material evidenced by magnetotelluric surveys. Thus, deformation imposed by the oblique convergence between South American and Nazca plates, while to the south being limited to the Liquiñe-Ofqui fault system that runs through the arc zone, in the retroarc area is located at the site of magmatic emplacement, presumably in association with a thermally weakened-upper crust. This control exemplifies the relationship that exists between surficial processes, magmatic emplacement and upper asthenospheric dynamics in the Southern Central Andes.

Diffuse Hard X-Ray Emission in Starburst Galaxies as Synchrotron from Very High Energy Electrons

NASA Astrophysics Data System (ADS)

Lacki, Brian C.; Thompson, Todd A.

2013-01-01

The origin of the diffuse hard X-ray (2-10 keV) emission from starburst galaxies is a long-standing problem. We suggest that synchrotron emission of 10-100 TeV electrons and positrons (e ±) can contribute to this emission, because starbursts have strong magnetic fields. We consider three sources of e ± at these energies: (1) primary electrons directly accelerated by supernova remnants, (2) pionic secondary e ± created by inelastic collisions between cosmic ray (CR) protons and gas nuclei in the dense interstellar medium of starbursts, and (3) pair e ± produced between the interactions between 10 and 100 TeV γ-rays and the intense far-infrared (FIR) radiation fields of starbursts. We create one-zone steady-state models of the CR population in the Galactic center (R <= 112 pc), NGC 253, M82, and Arp 220's nuclei, assuming a power-law injection spectrum for electrons and protons. We consider different injection spectral slopes, magnetic field strengths, CR acceleration efficiencies, and diffusive escape times, and include advective escape, radiative cooling processes, and secondary and pair e ±. We compare these models to extant radio and GeV and TeV γ-ray data for these starbursts, and calculate the diffuse synchrotron X-ray and inverse Compton (IC) luminosities of these starbursts in the models which satisfy multiwavelength constraints. If the primary electron spectrum extends to ~PeV energies and has a proton/electron injection ratio similar to the Galactic value, we find that synchrotron emission contributes 2%-20% of their unresolved, diffuse hard X-ray emission. However, there is great uncertainty in this conclusion because of the limited information on the CR electron spectrum at these high energies. IC emission is likewise a minority of the unresolved X-ray emission in these starbursts, from 0.1% in the Galactic center to 10% in Arp 220's nuclei, with the main uncertainty being the starbursts' magnetic field. We also model generic starbursts, including submillimeter galaxies, in the context of the FIR-X-ray relation, finding that anywhere between 0% and 16% of the total hard X-ray emission is synchrotron for different parameters, and up to 2% in the densest starbursts assuming an E -2.2 injection spectrum and a diffusive escape time of 10 Myr (E/3 GeV)-1/2 (h/100 pc). Neutrino observations by IceCube and TeV γ-ray data from HESS, VERITAS, and CTA can further constrain the synchrotron X-ray emission of starbursts. Our models do not constrain the possibility of hard, second components of primary e ± from sources like pulsars in starbursts, which could enhance the synchrotron X-ray emission further.

Pauli energy spectrum for twist-deformed spacetime

NASA Astrophysics Data System (ADS)

Daszkiewicz, Marcin

2018-04-01

In this paper, we define the Pauli Hamiltonian function for the twist-deformed N-enlarged Newton-Hooke spacetime provided by M. Daszkiewicz [Mod. Phys. Lett. A 27, 1250083 (2012)]. Further, we derive its energy spectrum, i.e. we find the corresponding eigenvalues as well as the proper eigenfunctions.

Deformation partitioning provides insight into elastic, plastic, and viscous contributions to bone material behavior.

PubMed

Ferguson, V L

2009-08-01

The relative contributions of elastic, plastic, and viscous material behavior are poorly described by the separate extraction and analysis of the plane strain modulus, E('), the contact hardness, H(c) (a hybrid parameter encompassing both elastic and plastic behavior), and various viscoelastic material constants. A multiple element mechanical model enables the partitioning of a single indentation response into its fundamental elastic, plastic, and viscous deformation components. The objective of this study was to apply deformation partitioning to explore the role of hydration, tissue type, and degree of mineralization in bone and calcified cartilage. Wet, ethanol-dehydrated, and PMMA-embedded equine cortical bone samples and PMMA-embedded human femoral head tissues were analyzed for contributions of elastic, plastic and viscous deformation to the overall nanoindentation response at each site. While the alteration of hydration state had little effect on any measure of deformation, unembedded tissues demonstrated significantly greater measures of resistance to plastic deformation than PMMA-embedded tissues. The PMMA appeared to mechanically stabilize the tissues and prevent extensive permanent deformation within the bone material. Increasing mineral volume fraction correlated with positive changes in E('), H(c), and resistance to plastic deformation, H; however, the partitioned deformation components were generally unaffected by mineralization. The contribution of viscous deformation was minimal and may only play a significant role in poorly mineralized tissues. Deformation partitioning enables a detailed interpretation of the elastic, plastic, and viscous contributions to the nanomechanical behavior of mineralized tissues that is not possible when examining modulus and contact hardness alone. Varying experimental or biological factors, such as hydration or mineralization level, enables the understanding of potential mechanisms for specific mechanical behavior patterns that would otherwise be hidden within a more complex set of material property parameters.

Isobaric analog states in rare-earth nuclei studied with the ( 3He, t) charge-exchange reaction at θL = 0°

NASA Astrophysics Data System (ADS)

Jänecke, J.; Aarts, E. H. L.; Drentje, A. G.; Harakeh, M. N.; Gaarde, C.

1983-02-01

The ( 3He, t) charge-exchange reaction leading to the ground-state isobaric analog states (IAS) of 152, 154, 156, 158, 160Gd, 160,162Dy, 162,164,166,168,170Er, 170, 172, 174, 176Yb and 176, 178, 180Hf has been studied at θL = 0° and E( 3He) = 60.5 MeV. The reaction 28Si( 3He, t) 28P was used for energy calibration. The centroid energies of most IAS were determined to ±6 keV. Coulomb displacement energies have been extracted from the measured Q-values. They display the influence of non-spherical nuclear shapes which increase the rms radii and lower the Coulomb displacement energies. The dependence on both quadrupole and hexadecapole deformations is apparent with deformation parameters in good agreement with results from other measurements. The total widths Γ of the IAS are in the range 30 to 110 keV. They increase more strongly with neutron excess than is known for the IAS of the Sn and Te isotopes. The width of the IAS of 176Yb is anomalously low. The zero-degree ( 3He, t) cross sections are in the range 5 to 20 μb/sr. They generally increase with neutron excess except for the sequence of Yb isotopes. No systematic dependence on ( N - Z) appears to exist. Excitation energies and zero-degree cross sections for the reactions 28Si( 3He, t) 28P, 16O( 3He,t) 16F and 12C( 3He,t) 12N are reported.

Morphology of subcortical brain nuclei is associated with autonomic function in healthy humans.

PubMed

Ruffle, James K; Coen, Steven J; Giampietro, Vincent; Williams, Steven C R; Apkarian, A Vania; Farmer, Adam D; Aziz, Qasim

2018-01-01

The autonomic nervous system (ANS) is a brain body interface which serves to maintain homeostasis by influencing a plethora of physiological processes, including metabolism, cardiorespiratory regulation and nociception. Accumulating evidence suggests that ANS function is disturbed in numerous prevalent clinical disorders, including irritable bowel syndrome and fibromyalgia. While the brain is a central hub for regulating autonomic function, the association between resting autonomic activity and subcortical morphology has not been comprehensively studied and thus was our aim. In 27 healthy subjects [14 male and 13 female; mean age 30 years (range 22-53 years)], we quantified resting ANS function using validated indices of cardiac sympathetic index (CSI) and parasympathetic cardiac vagal tone (CVT). High resolution structural magnetic resonance imaging scans were acquired, and differences in subcortical nuclei shape, that is, 'deformation', contingent on resting ANS activity were investigated. CSI positively correlated with outward deformation of the brainstem, right nucleus accumbens, right amygdala and bilateral pallidum (all thresholded to corrected P < 0.05). In contrast, parasympathetic CVT negatively correlated with inward deformation of the right amygdala and pallidum (all thresholded to corrected P < 0.05). Left and right putamen volume positively correlated with CVT (r = 0.62, P = 0.0047 and r = 0.59, P = 0.008, respectively), as did the brainstem (r = 0.46, P = 0.049). These data provide novel evidence that resting autonomic state is associated with differences in the shape and volume of subcortical nuclei. Thus, subcortical morphological brain differences in various disorders may partly be attributable to perturbation in autonomic function. Further work is warranted to investigate these findings in clinical populations. Hum Brain Mapp 39:381-392, 2018. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Microscopic description of quadrupole collectivity in neutron-rich nuclei across the N = 126 shell closure

NASA Astrophysics Data System (ADS)

Rodríguez-Guzmán, R.; Robledo, L. M.; Sharma, M. M.

2015-06-01

The quadrupole collectivity in Nd, Sm, Gd, Dy, Er, Yb, Hf and W nuclei with neutron numbers 122 ≤ N ≤ 156 is studied, both at the mean field level and beyond, using the Gogny energy density functional. Besides the robustness of the N = 126 neutron shell closure, it is shown that the onset of static deformations in those isotopic chains with increasing neutron number leads to an enhanced stability and further extends the corresponding two-neutron drip lines far beyond what could be expected from spherical calculations. Independence of the mean-field predictions with respect to the particular version of the Gogny energy density functional employed is demonstrated by comparing results based on the D1S and D1M parameter sets. Correlations beyond mean field are taken into account in the framework of the angular momentum projected generator coordinate method calculation. It is shown that N = 126 remains a robust neutron magic number when dynamical effects are included. The analysis of the collective wave functions, average deformations and excitation energies indicate that, with increasing neutron number, the zero-point quantum corrections lead to dominant prolate configurations in the 0{1/+}, 0{2/+}, 2{1/+} and 2{2/+} states of the studied nuclei. Moreover, those dynamical deformation effects provide an enhanced stability that further supports the mean-field predictions, corroborating a shift of the r-process path to higher neutron numbers. Beyond mean-field calculations provide a smaller shell gap at N = 126 than the mean-field one in good agreement with previous theoretical studies. However, the shell gap still remains strong enough in the two-neutron drip lines.

Cosmic ray isotope measurements with a new Cerenkov X total energy telescope

NASA Technical Reports Server (NTRS)

Webber, W. R.; Kish, J. C.; Schrier, D. A.

1985-01-01

Measurements of the isotopic composition of cosmic nuclei with Z = 7-20 are reported. These measurements were made with a new version of a Cerenkov x total E telescope. Path length and uniformity corrections are made to all counters to a RMS level 1%. Since the Cerenkov counter is crucial to mass measurements using the C x E technique - special care was taken to optimize the resolution of the 2.4 cm thick Pilot 425 Cerenkov counter. This counter exhibited a beta = 1 muon equivalent LED resolution of 24%, corresponding to a total of 90 p.e. collected at the 1st dynodes of the photomultiplier tubes.

Variations of the relative abundances of He, (C,N,O) and Fe-group nuclei in solar cosmic rays and their relationship to solar particle acceleration

NASA Technical Reports Server (NTRS)

Bertsch, D. L.; Biswas, S.; Fichtel, C. E.; Pellerin, C. J.; Reames, D. V.

1973-01-01

Measurements of the flux of helium nuclei in the 24 January 1971 event and of helium and (C,N,O) nuclei in the 1 September 1971 event are combined with previous measurements to obtain the relative abundances of helium, (C,N,O), and Fe-group nuclei in these events. These data are then summarized together with previously reported results to show that, even when the same detector system using a dE/dx plus range technique is used, differences in the He/(C,N,O) value in the same energy/nucleon interval are observed in solar cosmic ray events. Further, when the He/(C,N,O) value is lower the He/(Fe-group nuclei) value is also systematically lower in these large events. When solar particle acceleration theory is analyzed, it is seen that the results suggest that, for large events, Coulomb energy loss probably does not play a major role in determining solar particle composition at higher energies (10 MeV). The variations in multicharged nuclei composition are more likely due to partial ionization during the acceleration phase.

Analytical Solutions to Coupled HM Problems to Highlight the Nonlocal Nature of Aquifer Storage

NASA Astrophysics Data System (ADS)

De Simone, Silvia; Carrera, Jesús

2017-11-01

Specific storage reflects the volumetric deformation capacity of permeable media. Classical groundwater hydrology equates elastic storage to medium compressibility (plus fluid compressibility times porosity). However, it is unclear if storage behavior can be represented by a single parameter. Hydraulic gradients act as body forces that push the medium in the direction of flow causing it to deform instantaneously everywhere, i.e., even in regions where pressure would not have changed according to conventional fluid flow. Therefore, actual deformation depends not only on the mechanical properties of the medium but also on aquifer geometry and on surrounding strata, which act like constraints to displacements. Here we discuss the question and highlight the nonlocal nature of storage (i.e., the volume of water released at a point depends on the poroelastic response over the whole aquifer). Proper evaluation of transient pressure and water release from storage requires acknowledging the hydromechanical coupling, which generally involves the use of numerical methods. We propose analytical solutions to the HM problem of fluid injection (extraction) into finite aquifers with one-dimensional or cylindrical geometries. We find that pressure response is much faster (virtually instantaneous) and larger than expected from traditional purely hydraulic solutions when aquifer deformation is restrained, whereas the pressure response is reversed (i.e., pressure drop in response to injection) when the permeable medium is free to deform. These findings suggest that accounting for hydromechanical coupling may be required when hydraulic testing is performed in low permeability media, which is becoming increasingly demanded for energy-related applications.

On- and off-fault coseismic surface deformation associated with the September 2013 M7.7 Balochistan, Pakistan earthquake measured from mapping and automated pixel correlation

NASA Astrophysics Data System (ADS)

Gold, R. D.; Reitman, N. G.; Briggs, R. W.; Barnhart, W. D.; Hayes, G. P.

2014-12-01

The 24 September 2013 Mw7.7 Balochistan, Pakistan earthquake ruptured a ~200 km-long stretch of the Hoshab fault in southern Pakistan. We remotely measured the coseismic surface deformation field using high-resolution (0.5 m) pre- and post-event satellite imagery. We measured ~300 near-field (0-10 m from fault) laterally offset piercing points (streams, terrace risers, roads, etc.) and find peak left-lateral offsets of ~12-15 m. We characterized the far-field (0-10 km from fault) displacement field using manual (~250 measurements) and automated image cross-correlation methods (e.g., pixel tracking) and find peak displacement values of ~16 m, which commonly exceed the on-fault displacement magnitudes. Our preliminary observations suggest the following: (1) coseismic surface displacement typically increases with distance away from the surface trace of the fault (e.g., highest displacement values in the far field), (2) for certain locations along the fault rupture, as little as 50% of the coseismic displacement field occurred in the near-field; and (3) the magnitudes of individual displacements are inversely correlated to the width of the surface rupture zone (e.g., largest displacements where the fault zone is narrowest). This analysis highlights the importance of identifying field study sites spanning fault sections with narrow deformation zones in order to capture the entire deformation field. For regions of distributed deformation, these results would predict that geologic slip rate studies underestimate a fault's complete slip rate.

Genetic relationship between deformation and low-Ca content in olivine from magmatic systems: evidence from the Poyi ultramafic intrusion, NW China

NASA Astrophysics Data System (ADS)

Yao, Zhuo-sen; Qin, Ke-zhang; Xue, Sheng-chao

2017-12-01

The deformation features (e.g., undulose extinction and subgrain boundaries) and low Ca content (<1000 ppm) of high-Fo olivine have been widely used as indictors for the mantle origin of olivine in the past. However, grains with these characteristics are also found in some crustal intrusions, e.g., Duke Island and Bushveld complexes. Here, we study this type of olivine in the Poyi ultramafic intrusion, NW China, to trace the formation of these unusual features in magmatic systems. As a result of the possible Ca-depleted parental melt and low Ca olivine/melt partition coefficient, olivine from the Poyi intrusion is extremely depleted in Ca. On the other hand, it has been confirmed that trace elements with large ionic radii (e.g., Ca2+ and Al3+) are chemically segregated at the grain boundary of olivine, exerting a dragging influence on grain boundary processes (named as solute drag effect). In this regard, the low Ca content in olivine weakens the solute drag effect, and in doing so it enhances the rate and strength of grain deformation, which occurs to accommodate the stress derived by fast compaction of the crystal mush in Poyi intrusion. Therefore, there is a genetic relationship between the plastic deformation and low Ca content in olivines from magmatic cumulates, and this link is one of the reasons causing the widespread deformation observed in Ca-depleted olivine from Poyi and other intrusions. What is more important, this work fills the gaps in the interpretation of this type of olivine in volcanic rocks.

Seismic sources in El Salvador. A geological and geodetic contribution

NASA Astrophysics Data System (ADS)

Alonso-Henar, J.; Martínez-Díaz, J. J.; Benito, B.; Alvarez-Gomez, J. A.; Canora, C.; Capote, R.; Staller, A.; Tectónica Activa, Paleosismicidad y. Riesgos Asociados UCM-910368

2013-05-01

El Salvador Fault Zone is a deformation band of 150 km long and 20 km wide within the Salvadorian volcanic arc. This shear band distributes the deformation between main strike-slip faults trending N90°-100°E and around 30 km long, and secondary normal faults trending between N120°E and N170°E. The ESFZ continues westward and is relieved by the Jalpatagua Fault. Eastward ESFZ becomes less clear disappearing at Golfo de Fonseca. The ESFZ deforms and offsets quaternary deposits with a right lateral movement in its main segments. Five segments have been proposed for the whole fault zone, from the Jalpatagua Fault to the Golfo de Fonseca. Paleoseismic studies in the Berlin and San Vicente Segments reveal an important amount of quaternary deformation. In fact, the San Vicente Segment was the source of the February 13, 2001 destructive earthquake. In this work we propose 18 capable seismic sources within El Salvador. The slip rate of each source has been obtained through out the combination of GPS data and paleoseismic data when it has been possible. We also have calculated maximum theoretical intensities produced by the maximum earthquakes related with each fault. We have taken into account several scenarios considering different possible surface rupture lengths up to 50 km and Mw 7.6 in some of the strike slip faults within ESFZ.

ARL Summer Student Research Symposium Compendium of Abstracts. Volume 2

DTIC Science & Technology

2015-12-01

to withstand ballistic/blast impact. The mechanical response of these materials is primarily determined by the active deformation modes operating...atomic scale deformation mechanisms such as basal, prismatic, pyramidal slip and twinning on the microstructure of the system (i.e., loading orientation...deformation, the dependence of peak strength on grain size, and the mechanisms of failure are discussed. I wish to acknowledge the mentorship of Dr

A constitutive law for finite element contact problems with unclassical friction

NASA Technical Reports Server (NTRS)

Plesha, M. E.; Steinetz, B. M.

1986-01-01

Techniques for modeling complex, unclassical contact-friction problems arising in solid and structural mechanics are discussed. A constitutive modeling concept is employed whereby analytic relations between increments of contact surface stress (i.e., traction) and contact surface deformation (i.e., relative displacement) are developed. Because of the incremental form of these relations, they are valid for arbitrary load-deformation histories. The motivation for the development of such a constitutive law is that more realistic friction idealizations can be implemented in finite element analysis software in a consistent, straightforward manner. Of particular interest is modeling of two-body (i.e., unlubricated) metal-metal, ceramic-ceramic, and metal-ceramic contact. Interfaces involving ceramics are of engineering importance and are being considered for advanced turbine engines in which higher temperature materials offer potential for higher engine fuel efficiency.

Mesozoic to Eocene ductile deformation of western Central Iran: From Cimmerian collisional orogeny to Eocene exhumation

NASA Astrophysics Data System (ADS)

Kargaranbafghi, Fariba; Neubauer, Franz; Genser, Johann; Faghih, Ali; Kusky, Timothy

2012-09-01

To advance our understanding of the Mesozoic to Eocene tectonics and kinematics of basement units exposed in the south-western Central Iran plateau, this paper presents new structural and thermochronological data from the Chapedony metamorphic core complex and hangingwall units, particularly from the Posht-e-Badam complex. The overall Paleogene structural characteristics of the area are related to an oblique convergent zone. The Saghand area represents part of a deformation zone between the Arabian and Eurasian plates, and can be interpreted to result from the Central Iran intracontinental deformation acting as a weak zone during Mesozoic to Paleogene times. Field and microstructural evidence reveal that the metamorphic and igneous rocks suffered a ductile shear deformation including mylonitization at the hangingwall boundary of the Eocene Chapedony metamorphic core complex. Comparison of deformation features in the mylonites and other structural features within the footwall unit leads to the conclusion that the mylonites were formed in a subhorizontal shear zone by NE-SW stretching during Middle to Late Eocene extensional tectonics. The Chapedony metamorphic core complex is characterized by amphibolite-facies metamorphism and development of S and S-L tectonic fabrics. The Posht-e-Badam complex was deformed by two stages during Cimmerian tectonic processes forming the Paleo-Tethyan suture.

Rules governing the composition of revolving clusters in quasiband and prolate-deformation states of atomic nuclei

PubMed Central

Pauling, Linus

1982-01-01

A set of rules, involving the magic and semimagic values of neutron and proton numbers and the proton/neutron ratio, is formulated for the composition of the revolving clusters producing the values of the moment of inertia given by the differences in energy of the adjacent levels in quasibands and bands of nuclei. The cluster compositions assigned with use of these rules to isotopes of Kr, Sr, Zr, Mo, and the actinon nuclei and to successive levels of the ground-state band of 158Er lead to reasonable values of the radius of revolution (the distance from the center of the nonrevolving sphere to the center of the cluster). These values correspond to a spheron diameter of about 3.20 fm. PMID:16593256

Generalization of the NpNn scheme to nonyrast levels of even-even nuclei

NASA Astrophysics Data System (ADS)

Zhao, Y. M.; Arima, A.

2003-07-01

In this Brief Report we present the systematics of excitation energies for even-even nuclei in two regions: the 50

Elastic modulus and thermal stress in coating during heat cycling with different substrate shapes

NASA Astrophysics Data System (ADS)

Gaona, Daniel; Valarezo, Alfredo

2015-09-01

The elastic modulus of a deposit ( E d) can be obtained by monitoring the temperature (Δ T) and curvature (Δ k) of a one-side coated long plate, namely, a onedimensional (1D) deformation model. The aim of this research is to design an experimental setup that proves whether a 1D deformation model can be scaled for complex geometries. The setup includes a laser displacement sensor mounted on a robotic arm capable of scanning a specimen surface and measuring its deformation. The reproducibility of the results is verified by comparing the present results with Stony Brook University Laboratory's results. The Δ k-Δ T slope error is less than 8%, and the E d estimation error is close to 2%. These values reveal the repeatability of the experiments. Several samples fabricated with aluminum as the substrate and 100MXC nanowire (Fe and Cr alloy) as the deposit are analyzed and compared with those in finite element (FE) simulations. The linear elastic behavior of 1D (flat long plate) and 2D (squared plate) specimens during heating/cooling cycles is demonstrated by the high linearity of all Δ k-Δ T curves (over 97%). The E d values are approximately equal for 1D and 2D analyses, with a median of 96 GPa and standard deviation of 2 GPa. The correspondence between the experimental and simulated results for the 1D and 2D specimens reveals that deformation and thermal stress in coated specimens can be predicted regardless of specimen geometry through FE modeling and by using the experimental value of E d. An example of a turbine-bladeshaped substrate is presented to validate the approach.

q -deformed statistics and the role of light fermionic dark matter in SN1987A cooling

NASA Astrophysics Data System (ADS)

Guha, Atanu; J, Selvaganapathy; Das, Prasanta Kumar

2017-01-01

The light dark matter (≃1 - 30 MeV ) particles pair produced in electron-positron annihilation e-e+→ γ χ χ ¯ inside the supernova core can take away the energy released in the supernova SN1987A explosion. Working within the formalism of q -deformed statistics [with the average value of the supernovae core temperature (fluctuating) being TS N=30 MeV ] and using the Raffelt's criterion on the emissivity for any new channel ɛ ˙ (e+e-→χ χ ¯ )≤1 019 erg g-1 s-1 , we find that as the deformation parameter q changes from 1.0 (undeformed scenario) to 1.1 (deformed scenario), the lower bound on the scale Λ of the dark matter effective theory varies from 3.3 ×1 06 TeV to 3.2 ×1 07 TeV for a dark matter fermion of mass mχ=30 MeV . Using the optical depth criteria on the free streaming of the dark matter fermion, we find the lower bound on Λ ˜1 08 TeV for mχ=30 MeV . In a scenario, where the dark matter fermions are pair produced in the outermost sector of the supernova core [with radius 0.9 Rc≤r ≤Rc , Rc(=10 km ) being the supernova core radius or the radius of protoneutron star], we find that the bound on Λ (˜3 ×1 07 TeV ) obtained from SN cooling criteria (Raffelt's criteria) is comparable with the bound obtained from free streaming (optical depth criterion) for light fermion dark matter of mass mχ=10 - 30 MeV .

Use of the ( e , e prime n ) reaction to study the giant multipole resonances in sup 116 Sn

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miskimen, R.A.; Ammons, E.A.; Arruda-Neto, J.D.T.

1991-04-01

The giant multipole resonances in {sup 116}Sn have been studied using the ({ital e},{ital e}{prime}{ital n}) reaction. Data were taken at effective momentum transfers of 0.37, 0.45, and 0.55 fm{sup {minus}1} and a multipole analysis of the data was performed. The inferred multipole strength functions identify the {ital E}2 and {ital E}0 resonances as distinct peaks at 12.2 and 17.9 MeV, respectively. The energy-weighted sum-rule strengths for the {ital E}2 and {ital E}0 resonances, obtained using a Lorentzian fit to the data, are 34{plus minus}13% and 93{plus minus}37%. When compared with results from alpha scattering and pion scattering the sum-rulemore » strengths exhibit approximate agreement, but the {ital E}0 strength identified in this measurement lies at higher excitation energy, consistent with the trend observed in heavier nuclei. The ({ital e},{ital e}{prime}{ital n}) data are compared with a continuum random phase approximation (RPA) calculation of the {ital E}2 and {ital E}0 strengths, and with an open-shell RPA calculation of the {ital E}2 strength. Both calculations disagree with the data in the region of the {ital E}2 resonance.« less

Effect of channel coupling on the elastic scattering of lithium isotopes

NASA Astrophysics Data System (ADS)

Furumoto, T.; Suhara, T.; Itagaki, N.

2018-04-01

Herein, we investigated the channel coupling (CC) effect on the elastic scatterings of lithium (Li) isotopes (A =6 -9) for 12C and 28Si targets at E /A =50 -60 MeV. The wave functions of the Li isotopes were obtained using the stochastic multi-configuration mixing method based on the microscopic-cluster model. The proton radii of the 7Li, 8Li, and 9Li nuclei became smaller as the number of valence neutrons increased. The valence neutrons in the 8Li and 9Li nuclei exhibited a glue-like behavior, thereby attracting the α and t clusters. Based on the transition densities derived from these microscopic wave functions, the elastic-scattering cross section was calculated using a microscopic coupled-channel method with a complex G -matrix interaction. The existing experimental data for the elastic scatterings of the Li isotopes and 10Be nuclei were well reproduced. The Li isotope elastic cross sections were demonstrated for the 12C and 28Si targets at E /A =53 MeV. The glue-like effect of the valence neutrons on the Li isotope was clearly demonstrated by the CC effect on elastic scattering. Finally, we realize that the valence neutrons stabilized the bindings of the core parts and the CC effect related to core excitation was indeed reduced.

Cosmic Ray Observation at Mount Chacaltaya for beyond the Knee Region

NASA Astrophysics Data System (ADS)

Tsunesada, Y.; Kakimoto, F.; Furuhata, F.; Matsumoto, H.; Sugawara, T.; Wakamatsu, H.; Gotoh, E.; Nakatani, H.; Nishi, K.; Tajima, N.; Yamada, Y.; Shimoda, S.; Yoshii, H.; Kaneko, T.; Ogio, S.; Matsubara, Y.; Kadota, K.; Tokuno, H.; Mizumoto, Y.; Shirasaki, Y.; Toyoda, Y.; Burgoa, O.; Flores, V.; Miranda, P.; Salinas, J.; Velarde, A.

We have installed a new air shower array at Mount Chacaltaya (5,200m above sea level) to observe primary cosmic rays with energies greater than 1015 eV. In our previous experiments, we measured energy spectrum and nuclear composition of primary cosmic rays around the knee region. Above all, we obtained the cosmic ray composition with three independent techniques, namely from the equi-intensity cuts, the arrival time distributions of Cherenkov lights associated with air showers, and the lateral distributions of Cherenkov photons around the shower axis. All the results from these experiments are in agreement and show that the average mass of cosmic ray nuclei increases with energies below and above the knee, and dominated by heavier nuclei as iron at 1016 eV. This result is consistent with the confinement and rigidity dependent acceleration models, and suggests that the cosmic ray origins are supernova remnants of massive population as Wolf-Rayet stars. It is of quite interest whether the mass of cosmic ray nuclei continues to increase with energies, or decreases by contributions of lighter components expected from the extra-galactic cosmic ray models. In this paper, we describe the characteristics of the new array and preliminary results from the first observation.

Excitation energy dependence of fragment-mass distributions from fission of 180,190Hg formed in fusion reactions of 36Ar + 144,154Sm

DOE PAGES

Nishio, K.; Andreyev, A. N.; Chapman, R.; ...

2015-06-30

Mass distributions of fission fragments from the compound nuclei 180Hg and 190 Hg formed in fusion reactions 36Ar + 144 Smand 36Ar + 154Sm, respectively, were measured at initial excitation energies of E*( 180Hg) = 33-66 MeV and E*( 190Hg) = 48-71 MeV. In the fission of 180Hg, the mass spectra were well reproduced by assuming only an asymmetric-mass division, with most probable light and heavy fragment masses more » $$\\overline{A}_L$$/ $$\\overline{A}_H$$ = 79/101. The mass asymmetry for 180Hg agrees well with that obtained in the low-energy β +/EC-delayed fission of 180Tl, from our earlier ISOLDE(CERN) experiment. Fission of 190Hg is found to proceed in a similar way, delivering the mass asymmetry of $$\\overline{A}_L$$/ $$\\overline{A}_H$$ = 83/107, throughout the measured excitation energy range. The persistence as a function of excitation energy of the mass-asymmetric fission for both proton-rich Hg isotopes gives strong evidence for the survival of microscopic effects up to effective excitation energies of compound nuclei as high as 40 MeV. In conclusion, this behavior is different from fission of actinide nuclei and heavier mercury isotope 198Hg.« less

Ultra heavy cosmic ray experiment (A0178)

NASA Technical Reports Server (NTRS)

Thompson, A.; Osullivan, D.; Bosch, J.; Keegan, R.; Wenzel, K. P.; Jansen, F.; Domingo, C.

1992-01-01

The Ultra Heavy Cosmic Ray Experiment (UHCRE) is based on a modular array of 192 side viewing solid state nuclear track detector stacks. These stacks were mounted in sets of four in 48 pressure vessels using 16 peripheral LDEF trays. The geometry factor for high energy cosmic ray nuclei, allowing for Earth shadowing, was 30 sq m sr, giving a total exposure factor of 170 sq m sr y at an orbital inclination of 28.4 degs. Scanning results indicate that about 3000 cosmic ray nuclei in the charge region with Z greater than 65 were collected. This sample is more than ten times the current world data in the field (taken to be the data set from the HEAO-3 mission plus that from the Ariel-6 mission) and is sufficient to provide the world's first statistically significant sample of actinide cosmic rays. Results are presented including a sample of ultra heavy cosmic ray nuclei, analysis of pre-flight and post-flight calibration events and details of track response in the context of detector temperature history. The integrated effect of all temperature and age related latent track variations cause a maximum charge shift of + or - 0.8e for uranium and + or - 0.6e for the platinum-lead group. Astrophysical implications of the UHCRE charge spectrum are discussed.

Nuclear structure for SNe r- and neutrino processes

NASA Astrophysics Data System (ADS)

Suzuki, Toshio

2014-09-01

SNe r- and neutrino-processes are investigated based on recent advances in the studies of spin responses in nuclei. New shell-model Hamiltonians, which can well describe spin responses in nuclei with proper tensor components, are used to make accurate evaluations of reaction cross sections and rates in astrophysical processes. Nucleosyntheses in SNe r- and ν -processes as well as rp-processes are discussed with these new reaction rates with improved accuracies. (1) Beta-decay rates for N = 126 isotones are evaluated by shell-model calculations, and new rates are applied to study r-process nucleosynthesis in SNe's around its third peak as well as beyond the peak region up to uranium. (2) ν -processes for light-element synthesis in core-collapse SNe are studied with a new shell-model Hamiltonian in p-shell, SFO. Effects of MSW ν -oscillations on the production yields of 7Li and 11B and sensitivity of the yield ratio on ν -oscillation parameters are discussed. ν -induced reactions on 16O are also studied. (3) A new shell-model Hamiltonian in pf-shell, GXPF1J, is used to evaluate e-capture rates in pf-shell nuclei at stellar environments. New e-capture rates are applied to study nucleosynthesis in type-Ia supernova explosions, rp-process and X-ray bursts.

Fission barriers at the end of the chart of the nuclides

NASA Astrophysics Data System (ADS)

Möller, Peter; Sierk, Arnold J.; Ichikawa, Takatoshi; Iwamoto, Akira; Mumpower, Matthew

2015-02-01

We present calculated fission-barrier heights for 5239 nuclides for all nuclei between the proton and neutron drip lines with 171 ≤A ≤330 . The barriers are calculated in the macroscopic-microscopic finite-range liquid-drop model with a 2002 set of macroscopic-model parameters. The saddle-point energies are determined from potential-energy surfaces based on more than 5 000 000 different shapes, defined by five deformation parameters in the three-quadratic-surface shape parametrization: elongation, neck diameter, left-fragment spheroidal deformation, right-fragment spheroidal deformation, and nascent-fragment mass asymmetry. The energy of the ground state is determined by calculating the lowest-energy configuration in both the Nilsson perturbed-spheroid (ɛ ) and the spherical-harmonic (β ) parametrizations, including axially asymmetric deformations. The lower of the two results (correcting for zero-point motion) is defined as the ground-state energy. The effect of axial asymmetry on the inner barrier peak is calculated in the (ɛ ,γ ) parametrization. We have earlier benchmarked our calculated barrier heights to experimentally extracted barrier parameters and found average agreement to about 1 MeV for known data across the nuclear chart. Here we do additional benchmarks and investigate the qualitative and, when possible, quantitative agreement and/or consistency with data on β -delayed fission, isotope generation along prompt-neutron-capture chains in nuclear-weapons tests, and superheavy-element stability. These studies all indicate that the model is realistic at considerable distances in Z and N from the region of nuclei where its parameters were determined.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Möller, Peter; Sierk, Arnold J.; Ichikawa, Takatoshi

We present calculated fission-barrier heights for 5239 nuclides for all nuclei between the proton and neutron drip lines with 171 ≤ A ≤ 330. The barriers are calculated in the macroscopic-microscopic finite-range liquid-drop (FRLDM) with a 2002 set of macroscopic-model parameters. The saddle-point energies are determined from potential-energy surfaces based on more than five million different shapes, defined by five deformation parameters in the three-quadratic-surface shape parametrization: elongation, neck diameter, left-fragment spheroidal deformation, right-fragment spheroidal deformation, and nascent-fragment mass asymmetry. The energy of the ground state is determined by calculating the lowest-energy configuration in both the Nilsson perturbed-spheroid (ϵ) andmore » the spherical-harmonic (β) parametrizations, including axially asymmetric deformations. The lower of the two results (correcting for zero-point motion) is defined as the ground-state energy. The effect of axial asymmetry on the inner barrier peak is calculated in the (ϵ,γ) parametrization. We have earlier benchmarked our calculated barrier heights to experimentally extracted barrier parameters and found average agreement to about one MeV for known data across the nuclear chart. Here we do additional benchmarks and investigate the qualitative and, when possible, quantitative agreement and/or consistency with data on β-delayed fission, isotope generation along prompt-neutron-capture chains in nuclear-weapons tests, and superheavy-element stability. In addition these studies all indicate that the model is realistic at considerable distances in Z and N from the region of nuclei where its parameters were determined.« less

Primary Cosmic-Ray Spectra in the Knee Region

NASA Astrophysics Data System (ADS)

Ter-Antonyan, Samvel V.; Biermann, P. L.

2003-07-01

Using EAS inverse approach and KASCADE EAS data the primary energy spectra for different primary nuclei at energies 1015 - 1017 eV are obtained in the framework of multi-comp onent model of primary cosmic ray origin and QGSJET and SIBYLL interaction models. The rigidity-dep endent behavior of spectra is the same for two interaction models. The extrap olation of the obtained primary spectra in a 1017 - 1018 eV energy range displays a presence of the extragalactic component of primary cosmic rays.

A Regional Real-time Forecast of Marine Boundary Layers During VOCALS-REx

DTIC Science & Technology

2011-01-01

Condensation Nuclei) concentration pro- motes more precipitation, leading to the destruction and structural change of the clouds (e.g., Stevens et al...and Muñoz, 2004), investigations of cloud and dynamic pro- cesses in case studies (Mocko and Cotton , 1995; Mechem and Kogan, 2003; Thompson et al...land breeze, Geophys. Res. Lett., 32, L05605, doi:10.1029/2004GL022139, 2005. Golaz, J.-C., Larson, V. E., and Cotton ,W. R: A PDF-based model for

Chemical Agonists of the PML/Daxx Pathway for Prostate Cancer Therapy

DTIC Science & Technology

2011-04-01

positive nuclei. These data suggest that the assay is highly specific and will not suffer from promiscuous reactivity with NIH library compounds...Figure 16B). Strikingly, when we compared Daxx levels in PCa cell lines to a nontumorigenic human prostatic epithelial line, PWR -1E, they were...Lysates from six different cell types ( PWR -1E, ALVA-31 Daxx K/D, ALVA-31 WT, DU145, LNCaP, and PC3) were normalized for total protein content (60 μg

Geant4 Simulations for the Radon Electric Dipole Moment Search at TRIUMF

NASA Astrophysics Data System (ADS)

Rand, Evan; Bangay, Jack; Bianco, Laura; Dunlop, Ryan; Finlay, Paul; Garrett, Paul; Leach, Kyle; Phillips, Andrew; Svensson, Carl; Sumithrarachchi, Chandana; Wong, James

2010-11-01

The existence of a permanent electric dipole moment (EDM) requires the violation of time-reversal symmetry (T) or, equivalently, the violation of charge conjugation C and parity P (CP). Although no particle EDM has yet been found, current theories beyond the Standard Model, e.g. multiple-Higgs theories, left-right symmetry, and supersymmetry, predict EDMs within current experimental reach. In fact, present limits on the EDMs of the neutron, electron and ^199Hg atom have significantly reduced the parameter spaces of these models. The measurement of a non-zero EDM would be a direct measurement of the violation of time-reversal symmetry, and would represent a clear signal of new physics beyond the Standard Model. Recent theoretical calculations predict large enhancements in the atomic EDMs for atoms with octupole-deformed nuclei, making odd-A Rn isotopes prime candidates for the EDM search. The Geant4 simulations presented here are essential for the development towards an EDM measurement. They provide an accurate description of γ-ray scattering and backgrounds in the experimental apparatus, and are being used to study the overall sensitivity of the RnEDM experiment at TRIUMF in Vancouver, B.C.

Annual Technical Report, Materials Research Laboratory, 1 July 1981-30 June 1982.

DTIC Science & Technology

1982-06-30

of making source regions is best for our purposes. Principal Investizator: P.J. Stiles (Physics). Personnel: E . Crisman (Engineering) and J-I Lee...of Dislocation Substructure in Aluminum Single Crystals Following Dynamic Deformation," C.Y. Chiem and J. Duffy, MEA 79-23742/3, MRL E -137, October...Engineering), Y. Zuiki (Engineering), A. Azar (Engineering), E . Lavernia (Engineering), P. Rosakis (Engineering). Publications: "Experimental Determination of

Cytotoxic and genotoxic characterization of aluminum and silicon oxide nanoparticles in macrophages.

PubMed

Hashimoto, Masanori; Imazato, Satoshi

2015-05-01

Although aluminum oxide and silicon oxide nanoparticles are currently available as dental materials, there is a lack of basic information concerning their biocompatibility. This study evaluates the biological responses of cultured macrophages (RAW264) to aluminum oxide (Al2O3NPs) and silicon oxide nanoparticles (SiO2NPs) by analyzing cytotoxicity and genotoxicity. The nanoparticles are amorphous and spherical, with diameters of 13 nm for the Al2O3NPs and 12 nm for the SiO2NPs. The cultured RAW264 are exposed to the nanoparticles (NPs) and examined for cytotoxicity using the WST-8 cell viability and Hoechst/PI apoptosis assay, for genotoxicity by micronucleus analysis, for changes in nuclear shape (deformed nuclei) and for comet assay using confocal microscopy, and micromorphological analysis is done using scanning and transmission electron microscopes. Nuclei and DNA damage because of exposure to both types of NPs is observed by inmunostaining genotoxicity testing. The cytotoxicity and genotoxicity are well correlated in this study. Numerous NPs are observed as large aggregates in vesicles, but less or nonexistent NP internalization is seen in the nucleus or cytoplasm. These morphological results suggest that a primary cause of cell disruption is the chemical changes of the NPs in the low pH of vesicles (i.e., ionization of Al2O3 or SiO2) for both types of oxide NPs. Although further research on the elution of NP concentrations on cell or tissue activity under simulated clinical conditions is required, NP concentrations over 200 μg/mL are large enough to induce cytotoxic and genotoxic effects to cells. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Fate of 3H-thymidine labelled myogenic cells in regeneration of muscle isografts.

PubMed

Gutmann, E; Mares, V; Stichová, J

1976-03-05

Intact and denervated extensor digitorum longus (EDL) muscles of 20-day-old inbred Lewis-Wistar rats were labelled with 3H-thymidine. Ninety minutes after the injection of the isotope 4.0% of the nuclei were labelled in the intact (i.e. innervated) and 9.6% in the muscles, denervated 3 days before administration of the isotope. The labelled EDL muscles were grafted into the bed of the previously removed EDL muscles of inbred animals and these isografts were studied 30 days later. In the EDL muscles, regenerated from innervated isografts only occasionally labelled endothelial cells were found whereas in the muscles regenerated from denervated isografts also parenchymal muscle nuclei were regularly labelled. The incidence of labelled nuclei in the regenerated EDL muscles was, however, about 20 times lower than in the donor EDL muscles. The presen experiments provide a direct proof of utilization of donor satelite cell nuclei for regeneration in grafted muscle tissue. With respect to the low incidence of labelled nuclei in regenerated EDL muscles, other sources of cells apparently also contribute to the regeneration process.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Piccioli, Zachary; McKee, Courtney H.; Leszczynski, Anna

We investigated the nuclear import of low risk HPV11 E7 protein using 1) transfection assays in HeLa cells with EGFP fusion plasmids containing 11E7 and its domains and 2) nuclear import assays in digitonin-permeabilized HeLa cells with GST fusion proteins containing 11E7 and its domains. The EGFP-11E7 and EGFP-11cE7{sub 39-98} localized mostly to the nucleus. The GST-11E7 and GST-11cE7{sub 39-98} were imported into the nuclei in the presence of either Ran-GDP or RanG19V-GTP mutant and in the absence of nuclear import receptors. This suggests that 11E7 enters the nucleus via a Ran-dependent pathway, independent of nuclear import receptors, mediated bymore » a nuclear localization signal located in its C-terminal domain (cNLS). This cNLS contains the zinc binding domain consisting of two copies of Cys-X-X-Cys motif. Mutagenesis of Cys residues in these motifs changed the localization of the EGFP-11cE7/-11E7 mutants to cytoplasmic, suggesting that the zinc binding domain is essential for nuclear localization of 11E7.« less

A generalized law for brittle deformation of Westerly granite

USGS Publications Warehouse

Lockner, D.A.

1998-01-01

A semiempirical constitutive law is presented for the brittle deformation of intact Westerly granite. The law can be extended to larger displacements, dominated by localized deformation, by including a displacement-weakening break-down region terminating in a frictional sliding regime often described by a rate- and state-dependent constitutive law. The intact deformation law, based on an Arrhenius type rate equation, relates inelastic strain rate to confining pressure Pc, differential stress ????, inelastic strain ??i, and temperature T. The basic form of the law for deformation prior to fault nucleation is In ????i = c - (E*/RT) + (????/a??o)sin-??(???? i/2??o) where ??o and ??o are normalization constants (dependent on confining pressure), a is rate sensitivity of stress, and ?? is a shape parameter. At room temperature, eight experimentally determined coefficients are needed to fully describe the stress-strain-strain rate response for Westerly granite from initial loading to failure. Temperature dependence requires apparent activation energy (E* ??? 90 kJ/mol) and one additional experimentally determined coefficient. The similarity between the prefailure constitutive law for intact rock and the rate- and state-dependent friction laws for frictional sliding on fracture surfaces suggests a close connection between these brittle phenomena.

A Model for Estimating Nonlinear Deformation and Damage in Ceramic Matrix Composites (Preprint)

DTIC Science & Technology

2011-07-01

composite along a fiber direction are given by 2 EEE TL1   (A3) 1 TTLL 1 E2 EE     (A4) and the longitudinal (L) and transverse (T...properties of a single ply are given by  fMffL v1EvEE  (A5)   ffTfM MfT T v1EvE EE E   (A6)   L fMMfff L E v1EvE     (A7

GENETIC INFLUENCE OF APOE4 GENOTYPE ON HIPPOCAMPAL MORPHOMETRY - AN N=725 SURFACE-BASED ADNI STUDY

PubMed Central

Shi, Jie; Leporé, Natasha; Gutman, Boris A.; Thompson, Paul M.; Baxter, Leslie C.; Caselli, Richard L.; Wang, Yalin

2014-01-01

The apolipoprotein E (APOE) e4 allele is the most prevalent genetic risk factor for Alzheimer’s disease (AD). Hippocampal volumes are generally smaller in AD patients carrying the e4 allele compared to e4 non-carriers. Here we examined the effect of APOE e4 on hippocampal morphometry in a large imaging database – the Alzheimer’s Disease Neuroimaging Initiative (ADNI). We automatically segmented and constructed hippocampal surfaces from the baseline MR images of 725 subjects with known APOE genotype information including 167 with AD, 354 with mild cognitive impairment (MCI), and 204 normal controls. High-order correspondences between hippocampal surfaces were enforced across subjects with a novel inverse consistent surface fluid registration method. Multivariate statistics consisting of multivariate tensor-based morphometry (mTBM) and radial distance were computed for surface deformation analysis. Using Hotelling’s T2 test, we found significant morphological deformation in APOE e4 carriers relative to non-carriers in the entire cohort as well as in the non-demented (pooled MCI and control) subjects, affecting the left hippocampus more than the right, and this effect was more pronounced in e4 homozygotes than heterozygotes. Our findings are consistent with previous studies that showed e4 carriers exhibit accelerated hippocampal atrophy; we extend these findings to a novel measure of hippocampal morphometry. Hippocampal morphometry has significant potential as an imaging biomarker of early stage AD. PMID:24453132