Toward understanding the early stages of an impulsively accelerated coronal mass ejection

The expanding magnetic flux in coronal mass ejections (CMEs) often forms a cavity. A spherical model is simultaneously fit to STEREO EUVI and COR1 data of an impulsively accelerated CME on 25 March 2008, which displays a well-defined extreme ultraviolet (EUV) and white-light cavity of nearly circular shape already at low heights ~ 0.2 Rs. The center height h(t) and radial expansion r(t) of the cavity are obtained in the whole height range of the main acceleration. We interpret them as the axis height and as a quantity proportional to the minor radius of a flux rope, respectively. The three-dimensional expansion of the CME exhibits two phases in the course of its main upward acceleration. From the first h and r data points, taken shortly after the onset of the main acceleration, the erupting flux shows an overexpansion compared to its rise, as expressed by the decrease of the aspect ratio from k=h/r ~ 3 to k ~ (1.5-2.0). This phase is approximately coincident with the impulsive rise of the acceleration and is followed by a phase of very gradual change of the aspect ratio (a nearly self-similar expansion) toward k ~ 1.5 at h ~ 10 Rs. The initial overexpansion of the CME cavity can be caused by flux conservation around a rising flux rope of decreasing axial current and by the addition of flux to a growing, or even newly forming,flux rope by magnetic reconnection. Further analysis will be required to decide which of these contributions is dominant. The data also suggest that the horizontal component of the impulsive cavity expansion (parallel to the solar surface) triggers the associated EUV wave, which subsequently detaches from the CME volume.Comment: in press, A&A, 201

Characterisation of HTSC ceramics from their resistive transition

The resistivity vs. temperature relation in bulk ceramic HTSC under self-field conditions as well as in weak external magnetic fields is modelled by local Lorentz force induced fluxon motion with temperature dependent pinning. A pinning force density and two viscous drag coefficients in intergrain and intragrain regions, respectively, can be used as characteristic parameters describing the temperature, current, and external field dependences of the sample resistance.Comment: 12 pages, LaTeX2e, 6 figures (epsfig), to be published in Supercond. Sci. and Techno

Development of the Hedonic Overeating-Questionnaire (HEDO-Q)

Addictive-like eating is prevalent, but a clear conceptualization and operationalization outside of an addiction framework is lacking. By adopting a biopsychological framework of food reward, this study sought to develop and evaluate a brief self-report questionnaire for the trait assessment of hedonic overeating and dyscontrol. Items in the Hedonic Overeating-Questionnaire (HEDO-Q) were constructed following a rational approach and psychometrically evaluated in a large random sample from the German population (N = 2531). A confirmatory factor analysis supported the unidimensional nature of the six-item HEDO-Q with the three postulated components of wanting, liking, and dyscontrol. Psychometric properties were favorable with good corrected item-total correlations, acceptable item difficulty and homogeneity, and high internal consistency. Population norms were provided. The HEDO-Q revealed strict measurement invariance for sex and partial invariance for age and weight status. Discriminant validity was demonstrated in distinguishing participants with versus without eating disturbances or obesity. Associations with the established measures of eating disorder and general psychopathology supported the convergent and divergent validity of the HEDO-Q. This first evaluation indicates good psychometric properties of the HEDO-Q in the general population. Future validation work is warranted on the HEDO-Q's stability, sensitivity to change, and predictive and construct validity

Slow Rise and Partial Eruption of a Double-Decker Filament. I Observations and Interpretation

We study an active-region dextral filament which was composed of two branches separated in height by about 13 Mm. This "double-decker" configuration sustained for days before the upper branch erupted with a GOES-class M1.0 flare on 2010 August 7. Analyzing this evolution, we obtain the following main results. 1) During hours before the eruption, filament threads within the lower branch were observed to intermittently brighten up, lift upward, and then merge with the upper branch. The merging process contributed magnetic flux and current to the upper branch, resulting in its quasi-static ascent. 2) This transfer might serve as the key mechanism for the upper branch to lose equilibrium by reaching the limiting flux that can be stably held down by the overlying field or by reaching the threshold of the torus instability. 3) The erupting branch first straightened from a reverse S shape that followed the polarity inversion line and then writhed into a forward S shape. This shows a transfer of left-handed helicity in a sequence of writhe-twist-writhe. The fact that the initial writhe is converted into the twist of the flux rope excludes the helical kink instability as the trigger process of the eruption, but supports the occurrence of the instability in the main phase, which is indeed indicated by the very strong writhing motion. 4) A hard X-ray sigmoid, likely of coronal origin, formed in the gap between the two original filament branches in the impulsive phase of the associated flare. This supports a model of transient sigmoids forming in the vertical flare current sheet. 5) Left-handed magnetic helicity is inferred for both branches of the dextral filament. 6) Two types of force-free magnetic configurations are compatible with the data, a double flux rope equilibrium and a single flux rope situated above a loop arcade

Renormalisation of hierarchically interacting Cannings processes

In order to analyse universal patterns in the large space-time behaviour of interacting multi-type stochastic populations on countable geographic spaces, a key approach has been to carry out a renormalisation analysis in the hierarchical mean-field limit. This has provided considerable insight into the structure of interacting systems of finite-dimensional diffusions, such as Fisher-Wright or Feller diffusions, and their infinite-dimensional analogues, such as Fleming-Viot or Dawson-Watanabe superdiffusions. The present paper brings a new class of interacting jump processes into focus. We start from a single-colony $C^\Lambda$-process, which arises as the continuum-mass limit of a $\Lambda$-Cannings individual-based population model, where $\Lambda$ is a finite non-negative measure that describes the offspring mechanism, i.e., how individuals in a single colony are replaced via resampling. The key feature of the $\Lambda$-Cannings individual-based population model is that the offspring of a single individual can be a positive fraction of the total population. After that we introduce a system of hierarchically interacting $C^\Lambda$-processes, where the interaction comes from migration and reshuffling-resampling on all hierarchical space-time scales simultaneously. More precisely, individuals live in colonies labelled by the hierarchical group $\Omega_N$ of order N, and are subject to migration based on a sequence of migration coefficients \b{c}=(c_k)_{k \in N_0} and to reshuffling-resampling based on a sequence of resampling measures $\Lambda=(\Lambda_k)_{k \in N_0}$, both acting in k-blocks for all $k \in N_0$. The reshuffling is linked to the resampling: before resampling in a block takes place all individuals in that block are relocated uniformly, i.e., resampling is done in a locally ``panmictic'' manner. We refer to this system as the C^{\frac{\b{c};\Lambda}{N}}-process. The dual process of the $C^\Lambda$-process is the $\Lambda$-coalescent, whereas the dual process of the C^{\frac{\b{c};\Lambda}{N}}-process is a spatial coalescent with multi-level block coalescence. For the above system we carry out a full renormalisation analysis in the hierarchical mean-field limit $N \rightarrow \infty$. Our main result is that, in the limit as $N \rightarrow \infty$, on each hierarchical scale $k \in N_0$ the k-block averages of the C^{\frac{\b{c};\Lambda}{N}}-process converge to a random process that is a superposition of a $C^{\Lambda_k}$-process and a Fleming-Viot process, the latter with a volatility $d_k$ and with a drift of strength $c_k$ towards the limiting $(k+1)$-block average. It turns out that $d_k$ is a function of $c_l$ and $\Lambda_l$ for all $

In-line treatment of metal contaminated storm water by charred microporous polymers

CIVINS (Civilian Institutions) Thesis documentThis paper examines the feasibility of using an in-line storm water treatment system to remove heavy metals from storm water discharges. There are a number of commercially available microporous carbons that have a demonstrated affinity for the uptake of metals. Industry currently utilizes in-line storm water treatment processes to remove settle able solids, oils and greases; these processes could easily be altered to include the adsorption of dissolved contaminants such as metals. Two charred microporous polymers, Supelcarb(TM) and Carboxen-1011(TM) were measured for adsorption capacity for Cu(2+) and Ni(2+) removal in both batch and flow through experiments. Results indicate Cu(2+) was removed but not Ni(2+). A scenario was conducted based on experimentally derived Cu(2+) adsorption results to estimate the filter service time for the adsorbers tested when placed with in existing in-line storm water treatment system and exposed to Cu(2+) contaminated storm water. Storm water flows from 1, 2, 5, and 10 years storms were evaluated. Filter service time for the 1 year storm was 3.5 and 6 hours for Supelcarb(TM) and Carboxen-1011(TM) respectively. As storm intensity increased the filter service time decreased. This scenario illustrates that Supelcarb(TM) and Carboxen-1011(TM) are not good adsorbers in this situation. However, removal of heavy metal contaminated storm water by charred microporous polymer adsorption is a viable pollution control strategy.http://archive.org/details/inlinetreatmento1094524343U.S. Naval Postgraduate School, CIVINS programApproved for public release; distribution is unlimited

Effect of selected plant species within biodiverse pasture on in vitro fatty acid biohydrogenation and tissue fatty acid composition of lamb

The effect of botanical diversity on supply of polyunsaturated fatty acids (PUFA) to ruminants in vitro, and the fatty acid (FA) composition of muscle in lambs was investigated. Six plant species, commonly grown as part of UK herbal ley mixtures (Trifolium pratense, Lotus corniculatus, Achillea millefolium, Centaurea nigra, Plantago lanceolata and Prunella vulgaris), were assessed for FA profile, and in vitro biohydrogenation of constituent PUFA, to estimate intestinal supply of PUFA available for absorption by ruminants. Modelling the in vitro data suggested that L. Corniculatus and P. Vulgaris had the greatest potential to increase 18:3 n-3 supply to ruminants, having the highest amounts escaping in vitro biohydrogenation . Biodiverse pastures were established using the six selected species, under-sown in a perennial ryegrass-based sward. Lambs were grazed (~50 days) on biodiverse or control pastures and the effects on the FA composition of m. longissimus thoracis (lean and subcutaneous fat) and m. semimembranosus (lean) were determined. Biodiverse pasture increased 18:2 n-6 and 18:3 n-3 contents of m. semimembranosus (+14.8 and +7.2 mg/100g tissue respectively) and the subcutaneous fat of m. l. thoracis (+158 and +166 mg/100g tissue respectively) relative to feeding a perennial ryegrass pasture. However, there was no effect on total concentrations of saturated FA in the tissues studied. It was concluded that enhancing biodiversity had a positive impact on muscle FA profile reflected by increased levels of total PUFA