Ayahuasca’s ‘afterglow’: improved mindfulness and cognitive flexibility in ayahuasca drinkers

Rationale: There is a growing body of evidence demonstrating the therapeutic potential of ayahuasca for treating depression and anxiety. However, the mechanisms of action involved in ayahuasca’s therapeutic effects are unclear. Mindfulness and cognitive flexibility may be two possible psychological mechanisms. Like other classic psychedelics, ayahuasca also leads to an 'afterglow' effect of improved subjective wellbeing that persists after the acute effects have subsided. This period may offer a window of increased therapeutic potential. Objective: to explore changes in mindfulness and cognitive flexibility before, and within 24 hours after ayahuasca use. Methods: Forty-eight participants (54% female) were assessed on measures of mindfulness (Five Facets Mindfulness Questionnaire, FFMQ), decentering (Experiences Questionnaire, EQ) and cognitive flexibility (Cognitive Flexibility Scale, CFS), and completed the Stroop and Wisconsin Picture Card Sorting Task (WPCST) before drinking ayahuasca, and again within 24-hours. Results: Mindfulness (FFMQ total scores and four of the five mindfulness facets; Observe, Describe, Act with Awareness and Non-reactivity) and decentering (EQ) significantly increased in the 24 hours after ayahuasca use. Cognitive flexibility (CFS and WPCST) significantly improved in the 24 hours after ayahuasca use. Changes in both mindfulness and cognitive flexibility were not influenced by prior ayahuasca use. Conclusions: The present study supports ayahuasca’s ability to enhance mindfulness and further reports changes in cognitive flexibility in the 'afterglow' period occur, suggesting both could be possible psychological mechanisms concerning the psychotherapeutic effects of ayahuasca. Given psychological gains occurred regardless of prior ayahuasca use suggests potentially therapeutic effects for both naïve and experienced ayahuasca drinkers

Mean-Field Description of Fusion Barriers with Skyrme's Interaction

Fusion barriers are determined in the framework of the Skyrme energy-density functional together with the semi-classical approach known as the Extended Thomas-Fermi method. The barriers obtained in this way with the Skyrme interaction SkM* turn out to be close to those generated by phenomenological models like those using the proximity potentials. It is also shown that the location and the structure of the fusion barrier in the vicinity of its maximum and beyond can be quite accurately described by a simple analytical form depending only on the masses and the relative isospin of target and projectile nucleus.Comment: 7 pages, latex, 5 figure

Coordinate-space solution of the Skyrme-Hartree-Fock-Bogolyubov equations within spherical symmetry. The program HFBRAD (v1.0)

We describe the first version (v1.00) of the code HFBRAD which solves the Skyrme-Hartree-Fock or Skyrme-Hartree-Fock-Bogolyubov equations in the coordinate representation within the spherical symmetry. A realistic representation of the quasiparticle wave functions on the space lattice allows for performing calculations up to the particle drip lines. Zero-range density-dependent interactions are used in the pairing channel. The pairing energy is calculated by either using a cut-off energy in the quasiparticle spectrum or the regularization scheme proposed by A. Bulgac and Y. Yu.Comment: 39 pages, 9 figure

Continuum QRPA response for deformed neutron-rich nuclei

We discuss properties of the quadrupole collective excitation of the deformed neutron-rich nucleus $^{38}$Mg within the framework of quasi-particle random phase approximation (QRPA). We first solve the coupled-channels equations to obtain the single-particle levels, and construct the ground state by treating the pairing correlations in the BCS approximation. We then solve the QRPA equation using the response function formalism, by including the continuum spectra with the box dicscretization method. We show that the collectivity of the gamma vibration (the lowest $K^\pi=2^+$ mode) is significantly enhanced if protons and neutrons have different deformations. We also discuss an attempt towards full continuum QRPA calculations for deformed nuclei.Comment: 8 pages, 2 eps figures. Use espcrc1.sty. A talk given at the International Conference on Collective Motion in Nuclei Under Extreme Conditions (COMEX1), June 10 - 13, 2003, Paris, France. To be published in the proceedings (Nucl. Phys. A

Microscopic Transport Theory of Nuclear Processes

We formulate a microscopic theory of the decay of a compound nucleus through fission which generalizes earlier microscopic approaches of fission dynamics performed in the framework of the adiabatic hypothesis. It is based on the constrained Hartree-Fock-Bogoliubov procedure and the Generator Coordinate Method, and requires an effective nucleon-nucleon interaction as the only input quantity. The basic assumption is that the slow evolution of the nuclear shape must be treated explicitely, whereas the rapidly time-dependent intrinsic excitations can be treated by statistical approximations. More precisely, we introduce a reference density which represents the slow evolution of the nuclear shape by a reduced density matrix and the state of intrinsic excitations by a canonical distribution at each given shape of the nucleus. The shape of the nuclear density distribution is described by parameters ("generator coordinates"), not by "superabundant" degrees of freedom introduced in addition to the complete set of nucleonic degrees of freedom. We first derive a rigorous equation of motion for the reference density and, subsequently, simplify this equation on the basis of the Markov approximation. The temperature which appears in the canonical distribution is determined by the requirement that, at each time t, the reference density should correctly reproduce the mean excitation energy at given values of the shape parameters. The resulting equation for the "local" temperature must be solved together with the equations of motion obtained for the reduced density matrix.Comment: 33 pages, accepted in Nucl. Phys.

Superdeformed bands in neutron-rich Sulfur isotopes suggested by cranked Skyrme-Hartree-Fock calculations

On the basis of the cranked Skyrme-Hartree-Fock calculations in the three-dimensional coordinate-mesh representation, we suggest that, in addition to the well-known candidate 32S, the neutron-rich nucleus 36S and the drip-line nuclei,48S and 50S, are also good candidates for finding superdeformed rotational bands in Sulfur isotopes. Calculated density distributions for the superdeformed states in 48S and 50S exhibit superdeformed neutron skinsComment: 18 pages including 10 ps figure

Spin-orbit interaction in Hartree-Fock calculations

The contribution of the spin-orbit interaction in Hartree-Fock calculations for closed shell nuclei is studied. We obtain explicit expressions for the finite range spin-orbit force. New terms with respect to the traditional spin-orbit expressions are found. The importance of the finite-range is analyzed. Results obtained with spin-orbit terms taken from realistic interactions are presented. The effect of the spin-orbit isospin dependent terms is evaluated.Comment: To be published on Nuovo Cimento

Bulk properties of rotating nuclei and the validity of the liquid drop model at finite angular momenta

Out of self-consistent semi-classical calculations performed within the so-called Extended Thomas-Fermi approach for 212 nuclei at all even angular momentum values I ranging between 0 and 80 \hbar and using the Skyrme SkM* effective force, the I-dependence of associated liquid drop model parameters has been studied. The latter have been obtained trough separate fits of the calculated values of the strong interaction as well as direct and exchange Coulomb energies. The theoretical data basis so obtained, has allowed to make a rough quantitative assessment of the variation with I of the usual volume and surface energy parameters up to spin of \sim 30-40 \hbar. As a result of the combined variation of the surface and Coulomb energies, it has been shown that this I-dependence results in a significant enhancement of the fission stability of very heavy nuclei, balancing thus partially the well-known instability due to centrifugal forces.Comment: 27 pages, LaTeX (elsart) with 13 embeded postscript figure

Continuum quasiparticle random phase approximation and the time dependent Hartree-Fock-Bogoliubov approach

Quadrupole excitations of neutron-rich nuclei are analyzed by using the linear response method in the Quasiparticle Random Phase Approximation (QRPA). The QRPA response is derived starting from the time-dependent Hartree-Fock-Bogoliubov (HFB) equations. The residual interaction between the quasiparticles is determined consistently from the two-body force used in the HFB equations, and the continuum coupling is treated exactly. Calculations are done for the neutron-rich oxygen isotopes. It is found that pairing correlations affect the low-lying states, and that a full treatment of the continuum can change the structure of the states in the giant resonance region.Comment: 17 pages, 7 figures. Revised version with comments and references adde

Spin-Orbit Splitting in Non-Relativistic and Relativistic Self-Consistent Models

The splitting of single-particle energies between spin-orbit partners in nuclei is examined in the framework of different self-consistent approachs, non-relativistic as well as relativistic. Analytical expressions of spin-orbit potentials are given for various cases. Proton spin-orbit splittings are calculated along some isotopic chains (O, Ca, Sn) and they are compared with existing data. It is found that the isotopic dependence of the relativistic mean field predictions is similar to that of some Skyrme forces while the relativistic Hartree-Fock approach leads to a very different dependence due to the strong non-locality.Comment: 12 pages, RevTeX, 4 new figs.in .zip format, unchanged conclusions, Phys. ReV.