Risk of cancer following primary total hip replacement or primary resurfacing arthroplasty of the hip : A retrospective cohort study in Scotland

Acknowledgements: We are grateful to Lee Barnsdale, Doug Clark, and Richard Dobbie for advice and assistance with data preparation before analysis, and to the three anonymous referees for their helpful comments and suggestions.Peer reviewedPublisher PD

Perceived, anticipated and experienced stigma: exploring manifestations and implications for young people's sexual and reproductive health and access to care in North-Western Tanzania

This work was conducted under the HPP, a five-year cooperative agreement supported by United States Agency for International Development [grant number AID-OAA-A-10-00067]

Near Infrared Adaptive Optics Imaging of QSO Host Galaxies

We report near-infrared (primarily H-band) adaptive optics (AO) imaging with the Gemini-N and Subaru Telescopes, of a representative sample of 32 nearby (z<0.3) QSOs selected from the Palomar-Green (PG) Bright Quasar Survey (BQS), in order to investigate the properties of the host galaxies. 2D modeling and visual inspection of the images shows that ~36% of the hosts are ellipticals, \~39% contain a prominent disk component, and ~25% are of undetermined type. 30% show obvious signs of disturbance. The mean M_H(host) = -24.82 (2.1L_H*), with a range -23.5 to -26.5 (~0.63 to 10 L_H*). At <L_H*, all hosts have a dominant disk component, while at >2 L_H* most are ellipticals. "Disturbed" hosts are found at all M_H(host), while "strongly disturbed" hosts appear to favor the more luminous hosts. Hosts with prominent disks have less luminous QSOs, while the most luminous QSOs are almost exclusively in ellipticals or in mergers (which presumably shortly will be ellipticals). At z<0.13, where our sample is complete at B-band, we find no clear correlation between M_B(QSO) and M_H(host). However, at z>0.15, the more luminous QSOs (M_B<-24.7), and 4/5 of the radio-loud QSOs, have the most luminous H-band hosts (>7L_H*), most of which are ellipticals. Finally, we find a strong correlation between the "infrared-excess", L_IR/L_BB, of QSOs with host type and degree of disturbance. Disturbed and strongly disturbed hosts and hosts with dominant disks have L_IR/L_BB twice that of non-disturbed and elliptical hosts, respectively. QSOs with "disturbed" and "strongly-disturbed" hosts are also found to have morphologies and mid/far-infrared colors that are similar to what is found for "warm" ultraluminous infrared galaxies, providing further evidence for a possible evolutionary connection between both classes of objects.Comment: 80 pages, accepted for publication in ApJ Supp

Tensor polarizability and dispersive quantum measurement of multilevel atoms

Optimally extracting information from measurements performed on a physical system requires an accurate model of the measurement interaction. Continuously probing the collective spin of an Alkali atom cloud via its interaction with an off-resonant optical probe is an important example of such a measurement where realistic modeling at the quantum level is possible using standard techniques from atomic physics. Typically, however, tutorial descriptions of this technique have neglected the multilevel structure of realistic atoms for the sake of simplification. In this paper we account for the full multilevel structure of Alkali atoms and derive the irreducible form of the polarizability Hamiltonian describing a typical dispersive quantum measurement. For a specific set of parameters, we then show that semiclassical predictions of the theory are consistent with our experimental observations of polarization scattering by a polarized cloud of laser-cooled Cesium atoms. We also derive the signal-to-noise ratio under a single measurement trial and use this to predict the rate of spin-squeezing with multilevel Alkali atoms for arbitrary detuning of the probe beam.Comment: Significant corrections to theory and data. Full quality figures and other information available from http://minty.caltech.edu/papers.ph

Red Companions to a z=2.15 Radio Loud Quasar

We have conducted observations of the environment around the z=2.15 radio loud quasar 1550-269 in search of distant galaxies associated either with it or the z=2.09 CIV absorber along its line of sight. Such objects will be distinguished by their red colours, R-K>4.5. We find five such objects in a 1.5 arcmin^2 field around the quasar, with typical K magnitudes of ~20.4 and no detected R band emission. We also find a sixth object with K=19.6+/-0.3, and undetected at R, just two arcseconds from the quasar. The nature of all these objects is currently unclear, and will remain so until we have determined their redshifts. We suggest that it is likely that they are associated with either the quasar or the CIV absorber, in which case their properties might be similar to those of the z=2.38 red Ly-alpha emitting galaxies discovered by Francis et al. (1997). The small separation between the quasar and the brightest of our objects suggests that it may be the galaxy responsible for the CIV metal line absorption system. The closeness to the quasar and the red colour might have precluded similar objects from being uncovered in previous searches for emission from CIV and eg. damped absorbers.Comment: To appear in "Photometric Redshifts and High Redshift Galaxies", eds. R. Weymann, L. Storrie-Lombardi, M. Sawicki & R. Brunne

States for phase estimation in quantum interferometry

Ramsey interferometry allows the estimation of the phase $\phi$ of rotation of the pseudospin vector of an ensemble of two-state quantum systems. For $\phi$ small, the noise-to-signal ratio scales as the spin-squeezing parameter $\xi$, with $\xi<1$ possible for an entangled ensemble. However states with minimum $\xi$ are not optimal for single-shot measurements of an arbitrary phase. We define a phase-squeezing parameter, $\zeta$, which is an appropriate figure-of-merit for this case. We show that (unlike the states that minimize $\xi$), the states that minimize $\zeta$ can be created by evolving an unentangled state (coherent spin state) by the well-known 2-axis counter-twisting Hamiltonian. We analyse these and other states (for example the maximally entangled state, analogous to the optical "NOON" state $|\psi> = (|N,0>+|0,N>)/\sqrt{2}$) using several different properties, including $\xi$, $\zeta$, the coefficients in the pseudo angular momentum basis (in the three primary directions) and the angular Wigner function $W(\theta,\phi)$. Finally we discuss the experimental options for creating phase squeezed states and doing single-shot phase estimation.Comment: 8 pages and 5 figure

Dust-penetrated morphology in the high-redshift universe: clues from NGC 922

Results from the Hubble Deep Field (HDF) North and South show a large percentage of high-redshift galaxies whose appearance falls outside traditional classification systems. The nature of these objects is poorly understood, but sub-mm observations indicate that at least some of these systems are heavily obscured (Sanders 2000). This raises the intriguing possibility that a physically meaningful classification system for high-redshift galaxies might be more easily devised at rest-frame infrared wavelengths, rather than in the optical regime. Practical realization of this idea will become possible with the advent of the Next Generation Space Telescope (NGST). In order to explore the capability of NGST for undertaking such science, we present NASA-IRTF and SCUBA observations of NGC 922, a chaotic system in our local Universe which bears a striking resemblance to objects such as HDF 2-86 (z=0.749) in the HDF North. If objects such as NGC 922 are common at high-redshifts, then this galaxy may serve as a local morphological `Rosetta stone' bridging low and high-redshift populations. In this paper we demonstrate that quantitative measures of galactic structure are recoverable in the rest-frame infrared for NGC 922 seen at high redshifts using NGST, by simulating the appearance of this galaxy at redshifts z=0.7 and z=1.2 in rest-frame K'. Our results suggest that the capability of efficiently exploring the rest-wavelength IR morphology of high-z galaxies should probably be a key factor in deciding the final choice of instruments for the NGST.Comment: 7 pages, 12 Figures. Accepted for publication in A&A. Better version of the figures can be found at http://www.inaoep.mx/~puerari/ngs

Quasi-Stellar Objects, Ultraluminous IR Galaxies, and Mergers

We test the hypothesis that QSOs are formed via strong tidal interactions or mergers, initially going through an ultraluminous infrared phase, by looking for traces to this phase in the host galaxies of QSOs. We present a systematic spectroscopic and imaging study of a sample of QSOs that may be in a transitionary stage. By modeling the spectra, we obtain ages for the recent starburst events in the host galaxies and interacting companions. We have discussed in detail the first 5 objects in the sample in previous publications; here we present results for the remaining 4 objects, and discuss the sample as a whole. We find that all 9 transition QSOs are undergoing tidal interactions and that 8 are major mergers. Every object also shows strong recent star-forming activity, and in at least eight cases this activity is directly related to the tidal interaction. The ages we derive for the starburst populations range from currently active star formation in some objects, to post-starburst ages < 300 Myr in others. There is also a clear connection between interactions, starbursts, and QSO activity. Seven of the QSOs in the sample are also ULIGs; statistical considerations show that the two phenomena are necessarily physically related in these objects. Our results imply one of two scenarios: (1) at least some ULIGs evolve to become classical QSOs, and the transition stage lasts < 300 Myr, or (2) at least some QSOs are born under the same conditions as ULIGs, and their lifetime as QSOs lasts < 300 Myr. We discuss other properties and trends found in the sample, and propose a model that accounts for all of them, as well as the youth of these systems. (abridged)Comment: 57 pages; uses AASTeX 5.02 and includes 7 eps figures. 4 additional figures in jpeg format. Postscript and PDF versions, including all 11 figures, available at http://www.ifa.hawaii.edu/~canaguby/preprints.html To appear in the July 10 issue of Ap