Short-lived isomers in Po-192 and Po-194

Isomeric states in Po194 and Po192 were studied at the velocity filter SHIP. The isotopes were produced in the fusion-evaporation reactions Pr141(Fe56, p2n)Po194 and Sm144(V51, p2n)Po192. Several new γ-ray transitions were attributed to the isomers and γ−γ coincidences for both isomers were studied for the first time. The 459-keV transition earlier, tentatively proposed as de-exciting the isomeric level in Po194, was replaced by a new 248-keV transition, and the spin of this isomer was reassigned from (11−) to (10−). The de-excitation of the (11−) isomeric level in Po192 by the 154-keV transition was confirmed and a parallel de-excitation by a 733-keV (E3) transition to (8+) level of the ground-state band was suggested. Moreover, side feeding to the (4+) level of the ground-state band was proposed. The paper also discusses strengths of transitions de-exciting 11− isomers in neighboring Po and Pb isotopes

Alpha decay of 176Au

International audienceThe isotope Au176 has been studied in the complete fusion reaction Ca40+Pr141 → 176Au+5n at the velocity filter SHIP (GSI, Darmstadt). The complex fine-structure α decay of two isomeric states in Au176 feeding several previously unknown excited states in the daughter nucleus Ir172 is presented. An α-decay branching ratio of bα=9.5(11)% was deduced for the high-spin isomer in Ir172

Instability of the rhodium magnetic moment as origin of the metamagnetic phase transition in alpha-FeRh

Based on ab initio total energy calculations we show that two magnetic states of rhodium atoms together with competing ferromagnetic and antiferromagnetic exchange interactions are responsible for a temperature induced metamagnetic phase transition, which experimentally is observed for stoichiometric alpha-FeRh. A first-principle spin-based model allows to reproduce this first-order metamagnetic transition by means of Monte Carlo simulations. Further inclusion of spacial variation of exchange parameters leads to a realistic description of the experimental magneto-volume effects in alpha-FeRh.Comment: 10 pages, 13 figures, accepted for publication in Phys. Rev.

Emergence of qualia from brain activity or from an interaction of proto-consciousness with the brain: which one is the weirder? Available evidence and a research agenda

This contribution to the science of consciousness aims at comparing how two different theories can explain the emergence of different qualia experiences, meta-awareness, meta-cognition, the placebo effect, out-of-body experiences, cognitive therapy and meditation-induced brain changes, etc. The first theory postulates that qualia experiences derive from specific neural patterns, the second one, that qualia experiences derive from the interaction of a proto-consciousness with the brain\u2019s neural activity. From this comparison it will be possible to judge which one seems to better explain the different qualia experiences and to offer a more promising research agenda

Meditation-induced near-death experiences: a 3-year longitudinal study

Near-death experiences (NDEs) are life transformational events that are increasingly being subjected to empirical research. However, to date, no study has investigated the phenomenon of a meditation-induced near-death experience (MI-NDE) that is referred to in ancient Buddhist texts. Given that some advanced Buddhist meditators can induce NDEs at a pre-planned point in time, the MI-NDE may make NDEs more empirically accessible and thus advance understanding into the psychology of death-related processes. The present study recruited 12 advanced Buddhist meditators and compared the MI-NDE against two other meditation practices (i.e. that acted as control conditions) in the same participant group. Changes in the content and profundity of the MI-NDE were assessed longitudinally over a 3-year period. Findings demonstrated that compared to the control conditions, the MI-NDE prompted significantly greater pre-post increases in NDE profundity, mystical experiences and non-attachment. Furthermore, participants demonstrated significant increases in NDE profundity across the 3-year study period. Findings from an embedded qualitative analysis (using grounded theory) demonstrated that participants (i) were consciously aware of experiencing NDEs, (ii) retained volitional control over the content and duration of NDEs and (iii) elicited a rich array of non-worldly encounters and spiritual experiences. In addition to providing corroborating evidence in terms of the content of a “regular” (i.e. non-meditation-induced) NDE, novel NDE features identified in the present study indicate that there exist unexplored and/or poorly understood dimensions to NDEs. Furthermore, the study indicates that it would be feasible - including ethically feasible - for future research to recruit advanced meditators in order to assess real-time changes in neurological activity during NDEs

Repetitive N-WASP–Binding Elements of the Enterohemorrhagic Escherichia coli Effector EspFU Synergistically Activate Actin Assembly

Enterohemorrhagic Escherichia coli (EHEC) generate F-actin–rich adhesion pedestals by delivering effector proteins into mammalian cells. These effectors include the translocated receptor Tir, along with EspFU, a protein that associates indirectly with Tir and contains multiple peptide repeats that stimulate actin polymerization. In vitro, the EspFU repeat region is capable of binding and activating recombinant derivatives of N-WASP, a host actin nucleation-promoting factor. In spite of the identification of these important bacterial and host factors, the underlying mechanisms of how EHEC so potently exploits the native actin assembly machinery have not been clearly defined. Here we show that Tir and EspFU are sufficient for actin pedestal formation in cultured cells. Experimental clustering of Tir-EspFU fusion proteins indicates that the central role of the cytoplasmic portion of Tir is to promote clustering of the repeat region of EspFU. Whereas clustering of a single EspFU repeat is sufficient to bind N-WASP and generate pedestals on cultured cells, multi-repeat EspFU derivatives promote actin assembly more efficiently. Moreover, the EspFU repeats activate a protein complex containing N-WASP and the actin-binding protein WIP in a synergistic fashion in vitro, further suggesting that the repeats cooperate to stimulate actin polymerization in vivo. One explanation for repeat synergy is that simultaneous engagement of multiple N-WASP molecules can enhance its ability to interact with the actin nucleating Arp2/3 complex. These findings define the minimal set of bacterial effectors required for pedestal formation and the elements within those effectors that contribute to actin assembly via N-WASP-Arp2/3–mediated signaling pathways

First Experiment at TASCA Towards X-Ray Fingerprinting of Element 115 Decay Chains

To identify the atomic number of superheavy nuclei produced in Ca-48-induced fusion-evaporation reactions, an experiment aiming at measuring characteristic X-rays is being prepared at GSI, Darmstadt, Germany. The gas-filled separator TASCA will be employed, sending the residues towards the multi-coincidence detector setup TASISpec. Two ion-optical modes relying on differing magnetic polarities of the quadrupole magnets can be used at TASCA. New simulations and experimental tests of transmission and background suppression for these two focusing modes into TASISpec are presented