4,490 research outputs found

    Being, doing, and play: A theoretical and clinical exploration

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    This paper explores the metonymy of the following aphorism, delivered by Winnicott in a 1967 lecture: “From being comes doing, but there can be no do before be.” (1970, p. 25, emphasis in original). This aphorism has been little discussed or explored in the literature, but Winnicott articulated similar ideas in his more academic papers (e.g., 1965, 1970). These similar communications about being and doing will be examined alongside more contemporary thinking about the ideas to which Winnicott alludes in this aphorism; works by Benjamin (1988) and Akhtar (2000) in particular will be brought to bear on the subject. Two case studies will then be discussed, in order to examine the clinical implications of the theoretical discussion. Ultimately, such exploration will substantiate the claim that, through the metonymy of being and doing, Winnicott was alluding to a “statement of human nature” that he published just 3 years later (1970, p. 2). Winnicott’s own concept of play will then be posited as a critical, third element comprising “the life of a human being,” which will serve to situate the discussion within a contemporary, relational framework (1970, p. 2)

    The Spin Distribution of Fast Spinning Neutron Stars in Low Mass X-Ray Binaries: Evidence for Two Sub-Populations

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    We study the current sample of rapidly rotating neutron stars in both accreting and non-accreting binaries in order to determine whether the spin distribution of accreting neutron stars in low-mass X-ray binaries can be reconciled with current accretion torque models. We perform a statistical analysis of the spin distributions and show that there is evidence for two sub-populations among low-mass X-ray binaries, one at relatively low spin frequency, with an average of ~300 Hz and a broad spread, and a peaked population at higher frequency with average spin frequency of ~575 Hz. We show that the two sub-populations are separated by a cut-point at a frequency of ~540 Hz. We also show that the spin frequency of radio millisecond pulsars does not follow a log-normal distribution and shows no evidence for the existence of distinct sub-populations. We discuss the uncertainties of different accretion models and speculate that either the accreting neutron star cut-point marks the onset of gravitational waves as an efficient mechanism to remove angular momentum or some of the neutron stars in the fast sub-population do not evolve into radio millisecond pulsars.Comment: Submitted to Ap

    Dynamical mean-filed approximation to small-world networks of spiking neurons: From local to global, and/or from regular to random couplings

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    By extending a dynamical mean-field approximation (DMA) previously proposed by the author [H. Hasegawa, Phys. Rev. E {\bf 67}, 41903 (2003)], we have developed a semianalytical theory which takes into account a wide range of couplings in a small-world network. Our network consists of noisy NN-unit FitzHugh-Nagumo (FN) neurons with couplings whose average coordination number ZZ may change from local (ZNZ \ll N ) to global couplings (Z=N1Z=N-1) and/or whose concentration of random couplings pp is allowed to vary from regular (p=0p=0) to completely random (p=1). We have taken into account three kinds of spatial correlations: the on-site correlation, the correlation for a coupled pair and that for a pair without direct couplings. The original 2N2 N-dimensional {\it stochastic} differential equations are transformed to 13-dimensional {\it deterministic} differential equations expressed in terms of means, variances and covariances of state variables. The synchronization ratio and the firing-time precision for an applied single spike have been discussed as functions of ZZ and pp. Our calculations have shown that with increasing pp, the synchronization is {\it worse} because of increased heterogeneous couplings, although the average network distance becomes shorter. Results calculated by out theory are in good agreement with those by direct simulations.Comment: 19 pages, 2 figures: accepted in Phys. Rev. E with minor change

    IUE observations of Fe 2 galaxies

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    Repeated observations of the Seyfert 1 galaxies I Zw 1 and II Zw 136, which have very strong Fe II emission lines in the optical region, were made at low resolution with the IUE Satellite. The ultraviolet spectra are very similar: both are variable and show broad emission features of Fe II (especially the UV multiplets 1, 33, 60, 62, and 63) as well as the emission lines usually strong in Seyferts and quasars. The data strongly support the hypothesis that the optical Fe II emission lines are primarily due to collisional excitation and that resonance fluorescence makes only a minor contribution to the excitation of these lines

    Gravitational waves from rapidly rotating neutron stars

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    Rapidly rotating neutron stars in Low Mass X-ray Binaries have been proposed as an interesting source of gravitational waves. In this chapter we present estimates of the gravitational wave emission for various scenarios, given the (electromagnetically) observed characteristics of these systems. First of all we focus on the r-mode instability and show that a 'minimal' neutron star model (which does not incorporate exotica in the core, dynamically important magnetic fields or superfluid degrees of freedom), is not consistent with observations. We then present estimates of both thermally induced and magnetically sustained mountains in the crust. In general magnetic mountains are likely to be detectable only if the buried magnetic field of the star is of the order of B1012B\approx 10^{12} G. In the thermal mountain case we find that gravitational wave emission from persistent systems may be detected by ground based interferometers. Finally we re-asses the idea that gravitational wave emission may be balancing the accretion torque in these systems, and show that in most cases the disc/magnetosphere interaction can account for the observed spin periods.Comment: To appear in 'Gravitational Waves Astrophysics: 3rd Session of the Sant Cugat Forum on Astrophysics, 2014', Editor: Carlos F. Sopuert

    Gravitational wave emission from a magnetically deformed non-barotropic neutron star

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    A strong candidate for a source of gravitational waves is a highly magnetised, rapidly rotating neutron star (magnetar) deformed by internal magnetic stresses. We calculate the mass quadrupole moment by perturbing a zeroth-order hydrostatic equilibrium by an axisymmetric magnetic field with a \emph{linked poloidal-toroidal structure}. In this work, we do \emph{not} require the model star to obey a barotropic equation of state (as a realistic neutron star is not barotropic), allowing us to explore the hydromagnetic equilibria with fewer constraints. We derive the relation between the ratio of poloidal-to-total field energy Λ\Lambda and ellipticity ϵ\epsilon and briefly compare our results to those obtained using the barotropic assumption. Then, we present some examples of how our results can be applied to astrophysical contexts. First, we show how our formulae, in conjunction with current gravitational wave (non-)detections of the Crab pulsar and the Cassiopeia A central compact object (Cas A CCO), can be used to constrain the strength of the internal toroidal fields of those objects. We find that, for the Crab pulsar (whose canonical equatorial dipole field strength, inferred from spin down, is 4×1084\times 10^8 T) to emit detectable gravitational radiation, the neutron star must have a strong toroidal field component, with maximum internal toroidal field strength Btm=7×1012B_{\mathrm{tm}}=7\times 10^{12} T; for gravitational waves to be detected from the Cas A CCO at 300 Hz, Btm1013B_{\mathrm{tm}}\sim 10^{13} T, whereas detection at 100 Hz would require Btm1014B_{\mathrm{tm}}\sim 10^{14} T. Using our results, we also show how the gravitational wave signal emitted by a magnetar immediately after its birth (assuming it is born rapidly rotating, with Λ0.2\Lambda\lesssim 0.2) makes such a newborn magnetar a stronger candidate for gravitational wave detection than, for example, an SGR giant flare.Comment: 15 pages, 8 figures, 2 table

    Generalized Rate-Code Model for Neuron Ensembles with Finite Populations

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    We have proposed a generalized Langevin-type rate-code model subjected to multiplicative noise, in order to study stationary and dynamical properties of an ensemble containing {\it finite} NN neurons. Calculations using the Fokker-Planck equation (FPE) have shown that owing to the multiplicative noise, our rate model yields various kinds of stationary non-Gaussian distributions such as gamma, inverse-Gaussian-like and log-normal-like distributions, which have been experimentally observed. Dynamical properties of the rate model have been studied with the use of the augmented moment method (AMM), which was previously proposed by the author with a macroscopic point of view for finite-unit stochastic systems. In the AMM, original NN-dimensional stochastic differential equations (DEs) are transformed into three-dimensional deterministic DEs for means and fluctuations of local and global variables. Dynamical responses of the neuron ensemble to pulse and sinusoidal inputs calculated by the AMM are in good agreement with those obtained by direct simulation. The synchronization in the neuronal ensemble is discussed. Variabilities of the firing rate and of the interspike interval (ISI) are shown to increase with increasing the magnitude of multiplicative noise, which may be a conceivable origin of the observed large variability in cortical neurons.Comment: 19 pages, 9 figures, accepted in Phys. Rev. E after minor modification
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