Fragmentation and systematics of the Pygmy Dipole Resonance in the stable N=82 isotones

The low-lying electric dipole (E1) strength in the semi-magic nucleus 136Xe has been measured which finalizes the systematic survey to investigate the so-called pygmy dipole resonance (PDR) in all stable even N=82 isotones with the method of nuclear resonance fluorescence using real photons in the entrance channel. In all cases, a fragmented resonance-like structure of E1 strength is observed in the energy region 5 MeV to 8 MeV. An analysis of the fragmentation of the strength reveals that the degree of fragmentation decreases towards the proton-deficient isotones while the total integrated strength increases indicating a dependence of the total strength on the neutron-to-proton ratio. The experimental results are compared to microscopic calculations within the quasi-particle phonon model (QPM). The calculation includes complex configurations of up to three phonons and is able to reproduce also the fragmentation of the E1 strength which allows to draw conclusions on the damping of the PDR. Calculations and experimental data are in good agreement in the degree of fragmentation and also in the integrated strength if the sensitivity limit of the experiments is taken into account

Recurrence Quantification Analysis and Principal Components in the Detection of Short Complex Signals

Recurrence plots were introduced to help aid the detection of signals in complicated data series. This effort was furthered by the quantification of recurrence plot elements. We now demonstrate the utility of combining recurrence quantification analysis with principal components analysis to allow for a probabilistic evaluation for the presence of deterministic signals in relatively short data lengths.Comment: 10 pages, 3 figures; Elsevier preprint, elsart style; programs used for analysis available for download at http://homepages.luc.edu/~cwebbe

Radial orbit instability: review and perspectives

This paper presents elements about the radial orbit instability, which occurs in spherical self-gravitating systems with a strong anisotropy in the radial velocity direction. It contains an overview on the history of radial orbit instability. We also present the symplectic method we use to explore stability of equilibrium states, directly related to the dissipation induced instability mechanism well known in theoretical mechanics and plasma physics.Comment: 10 pages, submitted to Transport Theory and Statistical Physics, proceedings of Vlasovia 2009 International Conference. Corrected for typos, redaction, and references adde

Critical fluctuations in superconductors and the magnetic field penetration depth

The superconducting transition is studied within the one-loop renormalization group in fixed dimension $D=3$ and at the critical point. A tricritical behavior is found, and for $\kappa > \kappa_c$, an attractive charged fixed point, distinct from that of a neutral superfluid. The critical exponents of the continuous transition are evaluated, and it is shown that the anomalous dimension of the gauge field equals unity. This implies the proportionality of the magnetic field penetration depth and the superconducting correlation length below the transition. The penetration depth exponent is nonclassical. We argue that it can not be extracted from the dual theory in a straightforward manner since it is not renormalized by fluctuations of the dual field.Comment: 12 pages, LaTex, two figures available upon reques

Isospin Character of the Pygmy Dipole Resonance in 124Sn

The pygmy dipole resonance has been studied in the proton-magic nucleus 124Sn with the (a,a'g) coincidence method at E=136 MeV. The comparison with results of photon-scattering experiments reveals a splitting into two components with different structure: one group of states which is excited in (a,a'g) as well as in (g,g') reactions and a group of states at higher energies which is only excited in (g,g') reactions. Calculations with the self-consistent relativistic quasiparticle time-blocking approximation and the quasiparticle phonon model are in qualitative agreement with the experimental results and predict a low-lying isoscalar component dominated by neutron-skin oscillations and a higher-lying more isovector component on the tail of the giant dipole resonance

Learning to laugh : children and being human in early modern thought

This essay explores the construction of the human in early modern English thought, and uses discussions of the nature and use of laughter as a distinguishing feature of humanity from classical arguments as well as early modern ones. Using these classical, reformed English discussions of education and of the nature of children reveals an anxiety about the status of the child. Laughing appropriately - using tile mind and not merely the body - is a key feature of being human, and as such, the child's lack of "true' laughter reveals that child's status to be never always-already human. "Human' is a created rather than merely a natural status

Perceived coach autonomy support, basic need satisfaction and the well- and ill-being of elite youth soccer players: A longitudinal investigation

Objectives: Drawing from the Basic Needs Theory [BNT; Ryan, R. M., & Deci, E. L. (2002). An overview of self-determination theory. In E. L. Deci & R. M. Ryan (Eds.), Handbook of self-determination research (pp. 3-33). Rochester, NY: University of Rochester Press], the major purpose of the present study was to test a hypothesized sequence of temporal relationships between perceptions of coach autonomy support, basic need satisfaction and indices of well- and ill-being. A subsidiary aim was to ascertain the assumed mediational role of basic need satisfaction in explicating the perceived autonomy support and well-/ill-being relationships over time.\ud \ud Method: Participants (N = 54 males) from an elite youth soccer academy in the UK completed a multi-section questionnaire tapping the targeted variables on six occasions across two competitive seasons.\ud \ud Results: Multi-level regression analyses revealed that perceptions of coach autonomy support positively predicted within-person changes and between-person mean differences in basic need satisfaction and well-being over time. \ud \ud Satisfaction scores for the needs for competence and relatedness were found to predict within-person changes in subjective vitality. These same needs partially mediated the coach autonomy support-subjective vitality link over the two seasons.\ud \ud Conclusions: The findings partially support the tenets of BNT, and are discussed in terms of their practical application to participants involved in an elite youth sport setting. \u