A note on dual giant gravitons in AdS4×CP3AdS_{4}\times \mathbb{CP}^{3}

We study some of the properties of dual giant gravitons - D2-branes wrapped on an $S^{2}\subset AdS_{4}$ - in type IIA string theory on $AdS_{4}\times \mathbb{CP}^{3}$. In particular we confirm that the spectrum of small fluctuations about the giant is both real and independent of the size of the graviton. We also extend previously developed techniques for attaching open strings to giants to this D2-brane giant and focus on two particular limits of the resulting string sigma model: In the pp-wave limit we quantize the string and compute the spectrum of bosonic excitations while in the semiclassical limit, we read off the fast string Polyakov action and comment on the comparison to the Landau-Lifshitz action for the dual open spin chain.Comment: v3 significantly changed: added coupling to RR 1-form and turned on worldvolume gauge field, computed gauge field fluctuation, added comments on closure of the sl(2) sector and re-written to improve clarity. This version published in JHE

Acceleration of solar wind particles by traveling interplanetary shocks

The acceleration of thermal solar wind protons at spherical interplanetary shocks driven by coronal mass ejections is investigated. The solar wind velocity distribution is represented using $\kappa$-functions, which are transformed in response to simulated shock transitions in the fixed-frame flow speed, plasma number density, and temperature. These heated solar wind distributions are specified as source spectra at the shock from which particles with sufficient energy can be injected into the diffusive shock acceleration process. It is shown that for shock-accelerated spectra to display the classically expected power-law indices associated with the compression ratio, diffusion length scales must exceed the width of the compression region. The maximum attainable energies of shock-accelerated spectra are found to be limited by the transit times of interplanetary shocks, while spectra may be accelerated to higher energies in the presence of higher levels of magnetic turbulence or at faster-moving shocks. Indeed, simulations suggest fast-moving shocks are more likely to produce very high-energy particles, while strong shocks, associated with harder shock-accelerated spectra, are linked to higher intensities of energetic particles. The prior heating of the solar wind distribution is found to complement shock acceleration in reproducing the intensities of typical energetic storm particle events, especially where injection energies are high. Moreover, simulations of $\sim$0.2 to 1 MeV proton intensities are presented that naturally reproduce the observed flat energy spectra prior to shock passages. Energetic particles accelerated from the solar wind, aided by its prior heating, are shown to contribute substantially to intensities during energetic storm particle events.Comment: 26 pages, 21 figures, 5 tables. Accepted for publication in the Astrophysical Journa

Thermal simulation of magnetization reversals for size-distributed assemblies of core-shell exchange biased nanoparticles

A temperature dependent coherent magnetization reversal model is proposed for size-distributed assemblies of ferromagnetic nanoparticles and ferromagnetic-antiferromagnetic core-shell nanoparticles. The nanoparticles are assumed to be of uniaxial anisotropy and all aligned along their easy axis. The thermal dependence is included by considering thermal fluctuations, implemented via the N\'eel-Arrhenius theory. Thermal and angular dependence of magnetization reversal loops, coercive field and exchange-bias field are obtained, showing that F-AF size-distributed exchange-coupled nanoparticles exhibit temperature-dependent asymmetric magnetization reversal. Also, non-monotonic evolutions of He and Hc with T are demonstrated. The angular dependence of Hc with T exhibits a complex behavior, with the presence of an apex, whose position and amplitude are strongly T dependent. The angular dependence of He with T exhibits complex behaviors, which depends on the AF anisotropy and exchange coupling. The resulting angular behavior demonstrates the key role of the size distribution and temperature in the magnetic response of nanoparticles.Comment: Revised arguments in Introduction and last sectio

Oxford afrikaans–eng-els/english–afrikaans skoolwoordeboek/school dictionary.

Phillip Louw (Senior Redakteur/Senior Editor). Oxford Afrikaans–Eng-els/English–Afrikaans Skoolwoordeboek/School Dictionary. 2007, xii + 578 pp. ISBN 978 0 19 578742 9. Kaapstad/Cape Town: Oxford University Press Southern Africa (Pty) Ltd. Prys/Price: R99.95

SASPEN Case Study

Prenatally, the patient was diagnosed with dilated intestinal loops. The patient, born at term, was diagnosed with gastroschisis during the neonatal term

A note on the universality of the Hagedorn behavior of pp-wave strings

Following on from recent studies of string theory on a one-parameter family of integrable deformations of $AdS_{5}\times S^{5}$ proposed by Lunin and Maldacena, we carry out a systematic analysis of the high temperature properties of type IIB strings on the associated pp-wave geometries. In particular, through the computation of the thermal partition function and free energy we find that not only does the theory exhibit a Hagedorn transition in both the $(J,0,0)$ and $(J,J,J)$ class of pp-waves, but that the Hagedorn temperature is insensitive to the deformation suggesting an interesting universality in the high temperature behaviour of the pp-wave string theory. We comment also on the implications of this universality on the confinement/deconfinement transition in the dual $\mathcal{N}=1$ Leigh-Strassler deformation of ${\cal N}=4$ Yang-Mills theory.Comment: 25 pages; fixed minor typo; added reference

ABJM Dibaryon Spectroscopy

We extend the proposal for a detailed map between wrapped D-branes in Anti-de Sitter space and baryon-like operators in the associated dual conformal field theory provided in hep-th/0202150 to the recently formulated AdS_4 \times CP^3/ABJM correspondence. In this example, the role of the dibaryon operator of the 3-dimensional CFT is played by a D4-brane wrapping a CP^2 \subset CP^3. This topologically stable D-brane in the AdS_4 \times CP^3 is nothing but one-half of the maximal giant graviton on CP^3.Comment: 26 page

Beyond the Planar Limit in ABJM

In this article we consider gauge theories with a U(N)X U(N) gauge group. We provide, for the first time, a complete set of operators built from scalar fields that are in the bi fundamental of the two groups. Our operators diagonalize the two point function of the free field theory at all orders in 1/N. We then use this basis to investigate non-planar anomalous dimensions in the ABJM theory. We show that the dilatation operator reduces to a set of decoupled harmonic oscillators, signaling integrability in a nonplanar large N limit.Comment: v2: minor revisison

Is longpunksie-aspirasie 'n onskuldige prosedure?

Diagnostic lung punctures were done with parental consent in 29 previously untreated children aged 2 months to 9 years (median age 16 months), with radiologically proved broncho- or lobar pneumonia. Radiological examination was repeated after the procedure. Positive bacteriological cultures were obtained in 5 cases (17,2%): H. influenzae (2), a-haemolytic streptococci (2), and D. pneumoniae (1). Six patients (20,7%) developed overt pneumothorax and 1 had haemoptysis. All 7 patients recovered completely. Pneumothorax occurred in 5 of the 6 patients during the first 19 aspirations carried out by 6 different operators, while no local anaesthesia was used. The subsequent 11 punctures, among which only one case of pneumothorax occurred, were done by one person only after infiltration of the site with local anaesthetic. The incidence of pneumothorax seems to relate to the experience and skill of the operator, possibly to the use of local anaesthetic, and most important, whether identified by means of routine radiological examination after the procedure. Lung puncture does not appear to be an invariably innocuous procedure and should probably be reserved for special cases where uncommon aetiological agents are anticipated, for instance intractable pneumonitis accompanying immunodeficiency disease, the use of immunosuppressives, or with malignancy.S. Afr. Med. J. 48, 597 (1974)