Incidence and Survival for Merkel Cell Carcinoma in Queensland, Australia, 1993-2010

Importance: Merkel cell carcinoma (MCC) is an uncommon but highly invasive form of skin cancer. The mechanisms that cause MCC are yet to be fully determined. Objectives To compare the incidence and survival rates of MCC in Queensland, Australia, known to be a high-risk area, with MCC incidence and survival elsewhere in the world. We also analyzed incidence trends and differences in survival by key demographic and clinical characteristics. Design, Setting, and Participants: Retrospective cohort study of population-based administrative data for MCC collected by the Queensland Cancer Registry and supplemented with detailed histopathologic data. Deidentified records were obtained of all Queensland residents diagnosed as having MCC during the period from 1993 to 2010. A subsample of histopathologic records were reviewed by a senior dermatopathologist to determine the potential for misclassification. A total of 879 eligible cases of MCC were included in the study. Main Outcomes and Measures: Incidence rates were directly age standardized to the 2000 United States Standard Population. Trends were examined using Joinpoint software with results expressed in terms of the annual percentage change. The period method was used to calculate 5-year relative survival, and adjusted hazard ratios were obtained from multivariate Poisson models.Results: There were 340 cases of MCC diagnosed in Queensland between 2006 and 2010, corresponding to an incidence rate of 1.6 per 100 000 population. Men (2.5 per 100 000) had higher incidence than women (0.9 per 100 000), and rates peaked at 20.7 per 100 000 for persons 80 years or older. The overall incidence of MCC increased by an average of 2.6% per year from 1993 onwards. Relative survival was 41% after 5 years, with significantly better survival found for those younger than 70 years at diagnosis (56%-60%), those with tumors on the face or ears (51%), and those with stage I lesions (49%). Conclusions and Relevance: Incidence rates for MCC in Queensland are at least double those of any that have been previously published elsewhere in the world. It is likely that Queensland’s combination of a predominantly white population, outdoor lifestyle, and exposure to sunlight has played a role in this unwanted result. Interventions are required to increase awareness of MCC among clinicians and the public

A spectropolarimetric view on the nature of the peculiar Type I SN 2005hk

We report two spectropolarimetric observations of SN 2005hk, which is a close copy of the "very peculiar" SN 2002cx, showing low peak luminosity, slow decline, high ionization near peak and an unusually low expansion velocity of only about 7,000 km s^-1. Further to the data presented by Chornock et al., (2006), at -4 days before maximum, we present data of this object taken on 9 November 2005 (near maximum) and 23 November (+ two weeks) that show the continuum and most of the spectral lines to be polarized at levels of about 0.2-0.3%. At both epochs the data corresponds to the Spectropolarimetric Type D1. The general low level of line polarization suggests that the line forming regions for most species observed in the spectrum have a similar shape to that of the photosphere, which deviates from a spherical symmetry by <10%. In comparison with spectropolarimetry of Type Ia and Core-collapse SNe at similar epochs, we find that the properties of SN 2005hk are most similar to those of Type Ia SNe. In particular, we find the low levels of continuum and line polarization to indicate that the explosion mechanism is approximately spherical, with homogeneous ejecta (unlike the chemically segregated ejecta of CCSNe). We discuss the possibility that SN 2005hk was the result of the pure deflagration of a white dwarf and note the issues concerning this interpretation.Comment: ApJ accepted, uses emulateapj, 16 pages, 10 figures, figures 3 and 4 update

Spectropolarimetry of the Type Ia SN 2007sr Two Months After Maximum Light

We present late time spectropolarimetric observations of SN 2007sr, obtained with the VLT telescope at ESO Paranal Observatory when the object was 63 days after maximum light. The late time spectrum displays strong line polarization in the CaII absorption features. SN 2007sr adds to the case of some normal Type Ia SNe that show high line polarization or repolarization at late times, a fact that might be connected with the presence of high velocity features at early times

A Search for Variability in the Spectral Line Shapes of tau Bootis: Does this Star Really Have a Planet?

An analysis is made of the spectral line shapes of tau Bootis using high resolution (0.026 A) and high signal-to-noise (S/N~400) data in an effort to confirm the planet hypothesis for this star. Changes in the line shape are quantified using spectral line bisectors and line residuals. We detect no variations in either of these quantities above the level of the noise in the data. One spectral line, Fe I 6213 A, does show a hint of sinusoidal variations in the bisector velocity span when phased to the radial velocity period of 3.3 days, but this is not seen in the bisectors for two other lines, nor in the line residuals. Comparisons of the data to the bisector and residual variations expected for nonradial pulsations indicate that we can exclude those sectoral nonradial modes having m>2 and all sectoral modes with k>1, where k is the ratio of the horizontal to vertical velocities for the pulsations. The lack of line shape variability and the 469 m/s radial velocity amplitude is still consistent with nonradial sectoral modes m=1, and possibly m=2, but with k~1, which is at least 3 orders of magnitude less than the predicted value given the 3.3 day period of tau Bootis. Such low values of k can probably be excluded given the lack of photometric variations for this star. Although the measurements presented here do not prove, without any doubt, that tau Boo has a planetary companion, they do add significantly to the increasing body of evidence in favor of this hypothesis.Comment: LaTeX. 22 pages, 9 figures. Accepted in the Astrophysical Journa

Comparing P-stars with Observations

P-stars are compact stars made of up and down quarks in $\beta$-equilibrium with electrons in a chromomagnetic condensate. P-stars are able to account for compact stars as well as stars with radius comparable with canonical neutron stars. We compare p-stars with different available observations. Our results indicate that p-stars are able to reproduce in a natural manner several observations from isolated and binary pulsars.Comment: 15 pages, 2 figures; accepted for publication in Astrophysical Journa

A naked-eye triple system with a nonaccreting black hole in the inner binary

Several dozen optical echelle spectra demonstrate that HR 6819 is a hierarchical triple. A classical Be star is in a wide orbit with an unconstrained period around an inner 40 d binary consisting of a B3 III star and an unseen companion in a circular orbit. The radial-velocity semi-amplitude of 61.3 km/s of the inner star and its minimum (probable) mass of 5.0 Msun (6.3 +- 0.7 Msun) imply a mass of the unseen object of >= 4.2 Msun (>= 5.0 +- 0.4 Msun), that is, a black hole (BH). The spectroscopic time series is stunningly similar to observations of LB-1. A similar triple-star architecture of LB-1 would reduce the mass of the BH in LB-1 from ~70 Msun to a level more typical of Galactic stellar remnant BHs. The BH in HR 6819 probably is the closest known BH to the Sun, and together with LB-1, suggests a population of quiet BHs. Its embedment in a hierarchical triple structure may be of interest for models of merging double BHs or BH + neutron star binaries. Other triple stars with an outer Be star but without BH are identified; through stripping, such systems may become a source of single Be stars.Comment: Accepted as Letter to the Editor for A&