Characterizing quantum dynamics with initial system-environment correlations

We fully characterize the reduced dynamics of an open quantum system initially correlated with its environment. Using a photonic qubit coupled to a simulated environment we tomographically reconstruct a superchannel---a generalised channel that treats preparation procedures as inputs---from measurement of the system alone, despite its coupling to the environment. We introduce novel quantitative measures for determining the strength of initial correlations, and to allow an experiment to be optimised in regards to its environment.Comment: 10 pages, 15 figure

Confinement of the Sun's interior magnetic field: some exact boundary-layer solutions

High-latitude laminar confinement of the Sun's interior magnetic field is shown to be possible, as originally proposed by Gough and McIntyre (1998) but contrary to a recent claim by Brun and Zahn (A&A 2006). Mean downwelling as weak as 2x10^-6cm/s -- gyroscopically pumped by turbulent stresses in the overlying convection zone and/or tachocline -- can hold the field in advective-diffusive balance within a confinement layer of thickness scale ~ 1.5Mm ~ 0.002 x (solar radius) while transmitting a retrograde torque to the Ferraro-constrained interior. The confinement layer sits at the base of the high-latitude tachocline, near the top of the radiative envelope and just above the `tachopause' marking the top of the helium settling layer. A family of exact, laminar, frictionless, axisymmetric confinement-layer solutions is obtained for uniform downwelling in the limit of strong rotation and stratification. A scale analysis shows that the flow is dynamically stable and the assumption of laminar flow realistic. The solution remains valid for downwelling values of the order of 10^-5cm/s but not much larger. This suggests that the confinement layer may be unable to accept a much larger mass throughput. Such a restriction would imply an upper limit on possible internal field strengths, perhaps of the order of hundreds of gauss, and would have implications also for ventilation and lithium burning. The solutions have interesting chirality properties not mentioned in the paper owing to space restrictions, but described at http://www.atmos-dynamics.damtp.cam.ac.uk/people/mem/papers/SQBO/solarfigure.htmlComment: 6 pages, 3 figures, to appear in conference proceedings: Unsolved Problems in Stellar Physic

OncoLog Volume 51, Number 09, September 2006

Zeroing In on a Moving Target New Life for an Old Drug House Call: Managing Your Medications DiaLog: Adjuvant Therapy for Aggressive Kidney Cancer, by Christopher G. Wood, MD, Associate Professor of Urology and Cancer Biologyhttps://openworks.mdanderson.org/oncolog/1184/thumbnail.jp

Third Dredge-up in Low Mass Stars: Solving the LMC Carbon Star Mystery

A long standing problem with asymptotic giant branch (AGB) star models has been their inability to produce the low-luminosity carbon stars in the Large and Small Magellanic Clouds. Dredge-up must begin earlier and extend deeper. We find this for the first time in our models of LMC metallicity. Such features are not found in our models of SMC metallicity. The fully implicit and simultaneous stellar evolution code STARS has been used to calculate the evolution of AGB stars with metallicities of Z=0.008 and Z=0.004, corresponding to the observed metallicities of the Large and Small Magellanic Clouds, respecitively. Third dredge-up occurs in stars of 1Msol and above and carbon stars were found for models between 1Msol and 3Msol. We use the detailed models as input physics for a population synthesis code and generate carbon star luminosity functions. We now find that we are able to reproduce the carbon star luminosity function of the LMC without any manipulation of our models. The SMC carbon star luminosity function still cannot be produced from our detailed models unless the minimum core mass for third dredge-up is reduced by 0.06Msol.Comment: 6 pages, 5 figures. Accepted for publication in MNRA

Conservation Biology for Seven Palm Species from Diverse Genera

Arecaceae are a relatively large family with a considerable number of species of local and global socioeconomic importance. Many species are also under threat of impending extinction, indicating an urgent need to improve their conservation prospects. Here we present studies on seven palm species (Adonidia merrillii, Caryota urens, Livistona muelleri, Ravenea rivularis, Sabal [minor var. louisiana], Trachycarpus latisectus, and Wallichia disticha) from diverse genera in relation to various seed traits, including germination, desiccation tolerance, and weight. Germination varied from ca. 12-100% and mean time to germinate ranged from four days to four and one-half weeks at 30°C. Six of the species were newly screened for seed conservation biology and of these two were found to possess desiccationtolerant seeds, indicating opportunities for longer-term storage and improved use