Species-specific shifts in centromere sequence composition are coincident with breakpoint reuse in karyotypically divergent lineages

The evolution of three classes of centromere sequences across nine species of macropodine marsupials were compared with that of other genes, showing that each species has experienced differential expansion and contraction of individual classes

Understanding recruitment and retention in the NHS community pharmacy stop smoking service: perceptions of smoking cessation advisers

NIHR Programme Grants for Applied Research Programme (RP-PG-0609-10181

An Upper Mass Limit on a Red Supergiant Progenitor for the Type II-Plateau Supernova SN 2006my

We analyze two pre-supernova (SN) and three post-SN high-resolution images of the site of the Type II-Plateau supernova SN 2006my in an effort to either detect the progenitor star or to constrain its properties. Following image registration, we find that an isolated stellar object is not detected at the location of SN 2006my in either of the two pre-SN images. In the first, an I-band image obtained with the Wide-Field and Planetary Camera 2 on board the Hubble Space Telescope, the offset between the SN 2006my location and a detected source ("Source 1") is too large: > 0.08", which corresponds to a confidence level of non-association of 96% from our most liberal estimates of the transformation and measurement uncertainties. In the second, a similarly obtained V-band image, a source is detected ("Source 2") that has overlap with the SN 2006my location but is definitively an extended object. Through artificial star tests carried out on the precise location of SN 2006my in the images, we derive a 3-sigma upper bound on the luminosity of a red supergiant that could have remained undetected in our pre-SN images of log L/L_Sun = 5.10, which translates to an upper bound on such a star's initial mass of 15 M_Sun from the STARS stellar evolutionary models. Although considered unlikely, we can not rule out the possibility that part of the light comprising Source 1, which exhibits a slight extension relative to other point sources in the image, or part of the light contributing to the extended Source 2, may be due to the progenitor of SN 2006my. Only additional, high-resolution observations of the site taken after SN 2006my has faded beyond detection can confirm or reject these possibilities.Comment: Minor text changes from Version 1. Appendix added detailing the determination of confidence level of non-association of point sources in two registered astronomical image

Multiple sulfur isotope constraints on the sulfur cycle in the modern ocean

We present 28 multiple sulfur isotope measurements of seawater sulfate (δ34SSO4δ34SSO4 and Δ33SSO4Δ33SSO4) from the modern ocean over a range of water depths and sites along the eastern margin of the Pacific Ocean. The average measured δ34SSO4δ34SSO4 is 21.24‰ (±0.88‰,2σ±0.88‰,2σ) with a calculated Δ33SSO4Δ33SSO4 of +0.050‰+0.050‰ (±0.014‰,2σ±0.014‰,2σ). With these values, we use a box-model to place constraints on the gross fraction of pyrite burial in modern sediments. This model presents an improvement on previous estimates of the global pyrite burial flux because it does not rely on the assumed value of δ34Spyriteδ34Spyrite, which is poorly constrained, but instead uses new information about the relationship between δ34Sδ34S and δ33Sδ33S in global marine sulfate. Our calculations indicate that the pyrite burial flux from the modern ocean is between 10% and 45% of the total sulfur lost from the oceans, with a more probable range between 20% and 35%

Dealing with mobility: Understanding access anytime, anywhere

The rapid and accelerating move towards the adoption and use of mobile technologies has increasingly provided people and organisations with the ability to work away from the office and on the move. The new ways of working afforded by these technologies are often characterised in terms of access to information and people ‘anytime, anywhere’. This paper presents a study of mobile workers that highlights different facets of access to remote people and information, and different facets of anytime, anywhere. Four key factors in mobile work are identified from the study: the role of planning, working in ‘dead time’, accessing remote technological and informational resources, and monitoring the activities of remote colleagues. By reflecting on these issues, we can better understand the role of technology and artefact use in mobile work and identify the opportunities for the development of appropriate technological solutions to support mobile workers

Progenitor mass of the type IIP supernova 2005cs

The progenitor mass of type IIP supernova can be determined from either hydrodynamic modeling of the event or pre-explosion observations. To compare these approaches, we determine parameters of the sub-luminous supernova 2005cs and estimate its progenitor mass. We compute the hydrodynamic models of the supernova to describe its light curves and expansion velocity data. We estimate a presupernova mass of 17.3 Msun, an explosion energy of 4.1x10^{50} erg, a presupernova radius of 600 Rsun, and a radioactive Ni-56 mass of 0.0082 Msun. The derived progenitor mass of SN 2005cs is 18.2 Msun, which is in-between those of low-luminosity and normal type IIP supernovae. The obtained progenitor mass of SN 2005cs is higher than derived from pre-explosion images. The masses of four type IIP supernovae estimated by means of hydrodynamic modeling are systematically higher than the average progenitor mass for the 9-25 Msun mass range. This result, if confirmed for a larger sample, would imply that a serious revision of the present-day view on the progenitors of type IIP supernovae is required.Comment: 9 pages, 9 figures, 2 tables, accepted for publication in Astronomy & Astrophysic

Uranium tailings bibliography

A bibliography containing 1,212 references is presented with its focus on the general problem of reducing human exposure to the radionuclides contained in the tailings from the milling of uranium ore. The references are divided into seven broad categories: uranium tailings pile (problems and perspectives), standards and philosophy, etiology of radiation effects, internal dosimetry and metabolism, environmental transport, background sources of tailings radionuclides, and large-area decontamination. (JSR

Far-infrared vibrational properties of linear C60 polymers: A comparison between neutral and charged materials

We report the far-infrared transmittance spectrum of a pure phase of the orthorhombic high-temperature and high-pressure C-60 polymer and compare the results with a previously published spectrum of the charged RbC60 orthorhombic polymer. Assignments for both spectra are made with the aid of first-principles quantum molecular dynamics simulations of the two materials. We find that the striking spectral differences between the neutral and charged linear fullerene polymers can be fully accounted for by charge effects on the C-60 ball

On-chain electrodynamics of metallic (TMTSF)_2 X salts: Observation of Tomonaga-Luttinger liquid response

We have measured the electrodynamic response in the metallic state of three highly anisotropic conductors, (TMTSF)_2 X, where X=PF_6, AsF_6, or ClO_4, and TMTSF is the organic molecule tetramethyltetraselenofulvalene. In all three cases we find dramatic deviations from a simple Drude response. The optical conductivity has two features: a narrow mode at zero frequency, with a small spectral weight, and a mode centered around 200 cm^{-1}, with nearly all of the spectral weight expected for the relevant number of carriers and single particle bandmass. We argue that these features are characteristic of a nearly one-dimensional half- or quarter-filled band with Coulomb correlations, and evaluate the finite energy mode in terms of a one-dimensional Mott insulator. At high frequencies (\hbar\omega > t_\perp, the transfer integral perpendicular to the chains), the frequency dependence of the optical conductivity \sigma_1(\omega) is in agreement with calculations based on an interacting Tomonaga-Luttinger liquid, and is different from what is expected for an uncorrelated one-dimensional semiconductor. The zero frequency mode shows deviations from a simple Drude response, and can be adequately described with a frequency dependent mass and relaxation rate.Comment: 12 pages, 7 figures, RevTeX; minor corrections to text and references; To be published in Phys. Rev. B, 15 July 199