287 research outputs found
Double-resonant fast particle-wave interaction
In future fusion devices fast particles must be well confined in order to
transfer their energy to the background plasma. Magnetohydrodynamic
instabilities like Toroidal Alfv\'en Eigenmodes or core-localized modes such as
Beta Induced Alfv\'en Eigenmodes and Reversed Shear Alfv\'en Eigenmodes, both
driven by fast particles, can lead to significant losses. This is observed in
many ASDEX Upgrade discharges. The present study applies the drift-kinetic
HAGIS code with the aim of understanding the underlying resonance mechanisms,
especially in the presence of multiple modes with different frequencies. Of
particular interest is the resonant interaction of particles simultaneously
with two different modes, referred to as 'double-resonance'. Various mode
overlapping scenarios with different q profiles are considered. It is found
that, depending on the radial mode distance, double-resonance is able to
enhance growth rates as well as mode amplitudes significantly. Surprisingly, no
radial mode overlap is necessary for this effect. Quite the contrary is found:
small radial mode distances can lead to strong nonlinear mode stabilization of
a linearly dominant mode.Comment: 12 pages, 11 figures; Nuclear Fusion 52 (2012
Dissecting the Red Sequence--II. Star Formation Histories of Early-Type Galaxies Throughout the Fundamental Plane
This analysis uses spectra of ~16,000 nearby SDSS quiescent galaxies to track
variations in galaxy star formation histories along and perpendicular to the
Fundamental Plane (FP). We sort galaxies by their FP properties (sigma, R_e,
and I_e) and construct high S/N mean galaxy spectra that span the breadth and
thickness of the FP. From these spectra, we determine mean luminosity-weighted
ages, [Fe/H], [Mg/H], and [Mg/Fe] based on single stellar population models
using the method described in Graves & Schiavon (2008). In agreement with
previous work, the star formation histories of early-type galaxies are found to
form a two-parameter family. The major trend is that mean age, [Fe/H], [Mg/H],
and [Mg/Fe] all increase with sigma. However, no stellar population property
shows any dependence on R_e at fixed sigma, suggesting that sigma and not
dynamical mass (M_dyn ~ sigma^2 R_e) is the better predictor of past star
formation history. In addition to the main trend with sigma, galaxies also show
a range of population properties at fixed sigma that are strongly correlated
with surface brightness residuals from the FP, such that higher surface
brightness galaxies have younger mean ages, higher [Fe/H], higher [Mg/H], and
lower [Mg/Fe] than lower-surface brightness galaxies. These latter trends are a
major new constraint on star-formation histories.Comment: 23 pages, 14 figures. Accepted to Ap
Objective measurement of sedentary behaviour using accelerometers
Background: Sedentary behaviour (SB) is an important risk factor for a number of chronic diseases. Although gaps remain in our knowledge of the elements of SB most associated with reduced health outcomes, measuring SB is important, especially in less active patient populations where treatment-related changes may be seen first in changes in SB.Methods: We review current published work in the measurement of SB to make recommendations for SB measurement in clinical studies.Results: To help move our understanding of the area forward, we propose a set of derived measures of SB that can be easily understood and interpreted.Conclusion: Although there is more work required to determine and validate the most clinically relevant and sensitive measures of SB, there is enough understanding of how to measure SB to enable its inclusion in study protocols
Network analysis of the Viking Age in Ireland as portrayed in Cogadh Gaedhel re Gallaibh
Cogadh Gaedhel re Gallaibh (‘The War of the Gaedhil with the Gaill’) is a medieval Irish text, telling how an army under the leadership of Brian Boru challenged Viking invaders and their allies in Ireland, culminating with the Battle of Clontarf in 1014. Brian’s victory is widely remembered for breaking Viking power in Ireland, although much modern scholarship disputes traditional perceptions. Instead of an international conflict between Irish and Viking, interpretations based on revisionist scholarship consider it a domestic feud or civil war. Counterrevisionists challenge this view and a long-standing and lively debate continues. Here, we introduce quantitative measures to the discussions.We present statistical analyses of network data embedded in the text to position its sets of interactions on a spectrum from the domestic to the international. This delivers a picture that lies between antipodal traditional and revisionist extremes; hostilities recorded in the text are mostly between Irish and Viking—but internal conflict forms a significant proportion of the negative interactions too
The organic geochemistry of ancient sediments, part II
Chemical analysis of sediment and oil hydrocarbon content by gas chromatography and mass spectrometry to establish inception period of bio-organic evolutio
Simultaneous Attainment of High Electron and Ion Temperatures in ITB-Discharges with ECCD on ASDEX Upgrade
Spitzer IRS spectroscopy of 3CR radio galaxies and quasars: Testing the unified schemes
With the Spitzer Space Telescope Infrared Spectrograph (IRS) we have observed
seven powerful FR2 radio galaxies and seven quasars. Both samples, the galaxies
and the quasars, are comparable in isotropic 178 MHz luminosity (10^26.5 W/Hz <
P 178MHz < 10^29.5 W/Hz) and in redshift range (0.05 < z < 1.5). We find for
both samples similar distributions in the luminosity ratios of high- to
low-excitation lines ([NeV] 14.3 mu / [NeII] 12.8 mu) and of high-excitation
line to radio power ([NeV] 24.3 \mu / P 178MHz). This solves the long debate
about the apparent difference of quasars and radio galaxies in favor of the
orientation-dependent unified schemes. Furthermore, the luminosity ratio [OIII]
500.7 nm / [OIV] 25.9 mu of most galaxies is by a factor of ten lower than that
of the quasars. This suggests that the optical emission from the central NLR is
essentially absorbed (A_V} > 3) in the powerful FR2 galaxies and that the
[OIII] 500.7 nm luminosity does not serve as isotropic tracer for testing the
unified schemes.Comment: 5 pages, 3 figures, accepted as Letter for A&
A real-time, quantitative PCR method using hydrolysis probes for the monitoring of Plasmodium falciparum load in experimentally infected human volunteers
Background: The accurate quantification of Plasmodium falciparum parasite numbers by PCR is an important tool for monitoring growth kinetics in subjects infected and subsequently treated with anti-malarial agents
Litter size components in a full diallel cross of four maternal lines of rabbits
[EN] A crossbreeding experiment between 4 Spanish maternal lines of rabbits was performed to estimate crossbreeding effects on litter size components. The experiment was designed as a complete diallel cross involving 4 lines selected for litter size at weaning (A, V, H, and LP [L]) and their 12 simple crosses. Does from these 16 genetic groups were distributed among 4 Spanish farms, but only V line was present in all farms, allowing connectivity of the data. A total of 2,015 does in the third, fourth, or fifth gestations were subjected to laparoscopy. The recorded traits were ovulation rate (OR), number of implanted embryos (IE), total born (TB), embryo survival (ES), foetal survival (FS), and prenatal survival (PS). The differences in direct genetic effects, maternal genetic effects, and individual
heterosis between the lines were estimated according to Dickerson s model. Line A was significantly inferior to
lines V and H, whereas line LP was similar to A line, but for FS and PS, line A showed the best values, followed
by line LP. Comparing crossbred groups to line V, significant differences were shown favoring crossbred groups for OR and IE. The crossbred groups presented high implantation rate, but the foetal survival was lower than in V line. Important values for commercial production were presented by some crosses for OR (HV, 1.26 ova), IE (AH, 1.50 embryos; HV, 1.41 embryos), and TB (AH, 0.82 rabbits; HV, 0.78 rabbits). Relevant and significant reciprocal effects were found, especially for OR in all cases except the LV and VL crosses. These differences become nonsignificant in most of the other traits. Regarding direct genetic effects, line A presented lower estimates than the other lines with important values for OR, but the opposite was observed for FS. The maternal effects were significant only for some contrasts in OR and revealed that the LP line was inferior to the others (1.08 ova compared to the A line, 1.23 compared to the H line, and 0.38 compared to the V line). In general, high positive values for heterosis were found in crossbred does for OR and IE. The crosses, where lines A and H were involved, showed significant heterosis. The highest values were obtained by crossing lines A and H (1.18 ova for OR, 1.87 embryos for IE) followed by the cross
between lines H and V. Crosses between line LP and the other lines had a negative heterosis for FS and PS.This work was supported by the Spanish project AGL2011-30170 from the Spanish National Research Plan.Mohamed Ragab, M.; Sánchez Serrano, JP.; Mínguez Balaguer, C.; Vicente Antón, JS.; Baselga Izquierdo, M. (2014). Litter size components in a full diallel cross of four maternal lines of rabbits. Journal of Animal Science. 92(8):3231-3236. https://doi.org/10.2527/jas.2013-7286S3231323692
Influence of non-local thermodynamic equilibrium and Zeeman effects on magnetic equilibrium reconstruction using spectral motional Stark effect diagnostic
The Motional Stark Effect (MSE) diagnostic is a well established technique to infer the local internal magnetic field in fusion plasmas. In this paper, the existing forward model which describes the MSE data is extended by the Zeeman effect, fine-structure, and relativistic corrections in the interpretation of the MSE spectra for different experimental conditions at the tokamak ASDEX Upgrade. The contribution of the non-Local Thermodynamic Equilibrium (non-LTE) populations among the magnetic sub-levels and the Zeeman effect on the derived plasma parameters is different. The obtained pitch angle is changed by 3°…4° and by 0.5°…1° including the non-LTE and the Zeeman effects into the standard statistical MSE model. The total correction is about 4°. Moreover, the variation of the magnetic field strength is significantly changed by 2.2% due to the Zeeman effect only. While the data on the derived pitch angle still could not be tested against the other diagnostics, the results from an equilibrium reconstruction solver confirm the obtained values for magnetic field strength
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