223 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
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
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
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&
Detection of cold chain breaks using partial least squares-class modelling based on biogenic amine profiles in tuna
The maintenance of the cold chain is essential to ensure foodstuff conformity and safety. However, gaps in the cold chain may be expected so designing analytical methods capable to detect cold chain breaks is a worthwhile issue. In this paper, the possibility of using the amount of nine biogenic amines (BAs) determined in Thunnus albacares by HPLC-FLD for detecting cold chain breaks is approached. Tuna is stored at 3 different temperature conditions for 8 storage periods. The evolution of the content of BAs is analyzed through parallel factor analysis (PARAFAC), in such a way that storage temperature, BAs and storage time profiles are estimated. PARAFAC has made it possible to observe two spoilage routes with different relative evolution of BAs. In addition, it has enabled to estimate the storage time, by considering the three storage temperatures, with errors of 0.5 and 1.0 days in fitting and in prediction, respectively. Furthermore, a class-modelling technique based on partial least squares is sequentially applied to decide, from the amount of BAs, if there has been a cold chain break. Firstly, samples stored at 25 °C are statistically discriminated from those kept at 4 °C and −18 °C; next, frozen samples are distinguished from those refrigerated. In the first case, the probabilities of false non-compliance and false compliance are almost zero, whereas in the second one, both probabilities are 10%. Globally, the results of this work have pointed out the feasibility of using the amount of BAs together with PLS-CM to decide if the cold chain has been maintained or not.Agencia Estatal de Investigación of Spanish Ministerio de Economía, Industria y Competitividad, Gobierno de España [project CTQ2017-88894-R] and Consejería de Educación de la Junta de Castilla y León [project BU012P17] both co-financed with European Regional Development Fun
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
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
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
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
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