First comparison of wave observations from CoMP and AIA/SDO

Waves have long been thought to contribute to the heating of the solar corona and the generation of the solar wind. Recent observations have demonstrated evidence of quasi-periodic longitudinal disturbances and ubiquitous transverse wave propagation in many different coronal environments. This paper investigates signatures of different types of oscillatory behaviour, both above the solar limb and on-disk, by comparing findings from the Coronal Multi-channel Polarimeter (CoMP) and the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory (SDO) for the same active region. We study both transverse and longitudinal motion by comparing and contrasting time-distance images of parallel and perpendicular cuts along/across active region fan loops. Comparisons between parallel space-time features in CoMP Doppler velocity and transverse oscillations in AIA images are made, together with space-time analysis of propagating quasi-periodic intensity features seen near the base of loops in AIA. Signatures of transverse motions are observed along the same magnetic structure using CoMP Doppler velocity (Vphase=600-750km/s, P=3-6mins) and in AIA/SDO above the limb (P=3-8mins). Quasi-periodic intensity features (Vphase=100-200km/s, P=6-11mins) also travel along the base of the same structure. On the disk, signatures of both transverse and longitudinal intensity features were observed by AIA; both show similar properties to signatures found along structures anchored in the same active region three days earlier above the limb. Correlated features are recovered by space-time analysis of neighbouring tracks over perpendicular distances of <2.6Mm.Comment: 14 pages, 14 figures, 1 tabl

Re Burrard Yarrows Corporation, Vancouver Division, and International Brotherhood of Painters, Local 138

Union Grievance alleging improper contracting out. The union which is the grievor here is one of 11 unions signatory to the collective agreement with Burrard Yarrows Corporation — Vancouver Division. As an industrial collective agreement this poly-party agreement is somewhat unusual in that it provides for a form of closed shop union security with a role for the union hiring hall. At the same time it makes provision for seniority

Quantifying the Solar Cycle Modulation of Extreme Space Weather

By obtaining the analytic signal of daily sunspot numbers since 1818 we construct a new solar cycle phase clock that maps each of the last 18 solar cycles onto a single normalized 11 year epoch. This clock orders solar coronal activity and extremes of the aa index, which tracks geomagnetic storms at the Earth's surface over the last 14 solar cycles. We identify geomagnetically quiet intervals that are 40% of the normalized cycle, ±2π /5 in phase or ±2.2 years around solar minimum. Since 1868 only two severe (aa >300 nT) and one extreme (aa >500 nT) geomagnetic storms occurred in quiet intervals; 1–3% of severe (aa >300 nT) geomagnetic storms and 4–6% of C‐, M‐, and X‐class solar flares occurred in quiet intervals. This provides quantitative support to planning resilience against space weather impacts since only a few percent of all severe storms occur in quiet intervals and their start and end times are quantifiable

Evidence for a Black Hole and Accretion Disk in the LINER NGC 4203

We present spectroscopic observations from the Hubble Space Telescope that reveal for the first time the presence of a broad pedestal of Balmer-line emission in the LINER galaxy NGC 4203. The emission-line profile is suggestive of a relativistic accretion disk, and is reminiscent of double-peaked transient Balmer emission observed in a handful of other LINERs. The very broad line emission thus constitutes clear qualitative evidence for a black hole, and spatially resolved narrow-line emission in NGC 4203 can be used to constrain its mass, with M_BH less than 6 x 10^6 solar masses at 99.7% confidence. This value implies a ratio of black-hole mass to bulge mass of less than approximately 7 x 10^-4 in NGC 4203, which is less by a factor of ~3 - 9 than the mean ratio obtained for other galaxies. The availability of an independent constraint on central black-hole mass makes NGC4203 an important testbed for probing the physics of weak active galactic nuclei. Assuming M_BH near the detection limit, the ratio of observed luminosity to the Eddington luminosity is approximately 10^-4. This value is consistent with advection-dominated accretion, and hence with scenarios in which an ion torus irradiates an outer accretion disk that produces the observed double-peaked line emission. Follow-up observations will make it possible to improve the black-hole mass estimate and study variability in the nuclear emission.Comment: 10 pages (LaTeX, AASTeX v4.0), 2 postscript figures, accepted for publication in The Astrophysical Journal Letter

Tidal effects and the Proximity decay of nuclei

We examine the decay of the 3.03 MeV state of $^8$Be evaporated from an excited projectile-like fragment following a peripheral heavy-ion collision. The relative energy of the daughter $\alpha$ particles exhibits a dependence on the decay angle of the $^8$Be$^*$, indicative of a tidal effect. Comparison of the measured tidal effect with a purely Coulomb model suggests the influence of a measurable nuclear proximity interaction.Comment: 5 pages, 4 figure

Empirical Solar Wind Forecasting from the Chromosphere

Recently, we correlated the inferred structure of the solar chromospheric plasma topography with solar wind velocity and composition data measured at 1AU. We now offer a physical justification of these relationships and present initial results of a empirical prediction model based on them. While still limited by the fundamentally complex physics behind the origins of the solar wind and how its structure develops in the magnetic photosphere and expands into the heliosphere, our model provides a near continuous range of solar wind speeds and composition quantities that are simply estimated from the inferred structure of the chromosphere. We suggest that the derived quantities may provide input to other, more sophisticated, prediction tools or models such as those to study Coronal Mass Ejections (CME) propagation and Solar Energetic Particle (SEP) generation.Comment: In Press ApJ [March 2007] - 14 pages, 4 figures, one movie [available on request

Biomineralization of PbS and PbS-CdS core-shell nanocrystals and their application in quantum dot sensitized solar cells

Biomineralization utilizes biological systems to synthesize functional inorganic materials for application in diverse fields. In the current work, we enable biomineralization of quantum confined PbS and PbS–CdS core–shell nanocrystals and demonstrate their application in quantum dot sensitized solar cells (QDSSCs). An engineered strain of Stenotrophomonas maltophilia is utilized to generate a cystathionine γ-lyase that is active for the biomineralization of metal sulfide nanocrystals from a buffered aqueous solution of metal salts and L-cysteine. In the presence of lead acetate, this enzymatic route generates rock salt structured PbS nanocrystals. Controlling the growth conditions yields ∼4 nm PbS crystals with absorption and photoluminescence peaks at 910 nm and 1080 nm, respectively, consistent with the expected strong quantum confinement of PbS at this size. Quantum yields (QY) of the biomineralized PbS quantum dots, determined after phase transfer to the organic phase, range between 16 and 45%. These are the highest reported QY values for any biomineralized quantum dot materials to date and are comparable with QYs reported for chemically synthesized materials. Subsequent exposure to cadmium acetate results in the biomineralization of a thin CdS shell on the PbS core with a resultant blue-shift in optical properties. The photoluminescence peak shifts to 980 nm, consistent with the expected decrease in band gap energy of a PbS–CdS core–shell heterostructured quantum dot. HAADF-STEM imaging confirms the crystalline structure and size of the particles with complimentary XEDS analysis confirming the presence of Cd, Pb, and S in individual nanocrystals. Integration of these QDs into QDSSCs yields open circuit potentials of 0.43 V and 0.59 V for PbS and PbS–CdS, respectively, consistent with expectations for these materials and previously reported values for chemically synthesized QDs

Energy Distribution of Micro-events in the Quiet Solar Corona

Recent imaging observations of EUV line emissions have shown evidence for frequent flare-like events in a majority of the pixels in quiet regions of the solar corona. The changes in coronal emission measure indicate impulsive heating of new material to coronal temperatures. These heating or evaporation events are candidate signatures of "nanoflares" or "microflares" proposed to interpret the high temperature and the very existence of the corona. The energy distribution of these micro-events reported in the literature differ widely, and so do the estimates of their total energy input into the corona. Here we analyze the assumptions of the different methods, compare them by using the same data set and discuss their results. We also estimate the different forms of energy input and output, keeping in mind that the observed brightenings are most likely secondary phenomena. A rough estimate of the energy input observed by EIT on the SoHO satellite is of the order of 10% of the total radiative output in the same region. It is considerably smaller for the two reported TRACE observations. The discrepancy can be explained partially by different thresholds for flare detection. There is agreement on the slope and the absolute value of the distribution if the same method were used and a numerical error corrected. The extrapolation of the power law to unobserved energies that are many orders of magnitude smaller remains questionable. Nevertheless, these micro-events and unresolved smaller events are currently the best source of information on the heating process of the corona