295 research outputs found
The shape of Fe K line emitted from relativistic accretion disc around AGN black holes
The relativistically broadened Fe K line, originating from the
accretion disc in a vicinity of a super massive black hole, is observed in only
less than 50\% of type 1 Active Galactic Nuclei (AGN). In this study we
investigate could this lack of detections be explained by the effects of
certain parameters of the accretion disc and black hole, such as the
inclination, the inner and outer radius of disc and emissivity index. In order
to determine how these parameters affect the Fe K line shape, we
simulated about 60,000 Fe K line profiles emitted from the
relativistic disc.
Based on simulated line profiles, we conclude that the lack of the Fe
K line detection in type 1 AGN could, be caused by the specific
emitting disc parameters, but also by the limits in the spectral resolution and
sensitivity of the X-ray detectors.Comment: Based on the talk presented Balkan Workshop BW2018 (10-14 June 2018,
Ni\v{s}, Serbia), accepted for publishing in International Journal of Modern
Physics A, 8 figures, 1 table, 15 page
Pea-Barley Bi-Crop Silage in Milk Production
Whole crop silage (WCS) from barley or wheat has many advantages as roughage feed. The possibility to use the same harvest machinery as in harvesting grass reduces investment costs. The farms which are specialised in grass production may have shortage of open field area for manure spreading, in which case WCS can be the answer. However, digestibility and protein content of WCS is usually lower than in grass silage, which is limiting the feed intake and performance of the dairy cows. Cultivation of grains with grain legumes increases digestibility and protein content of the stand (Lunnan, 1988). Feeding of bi-crop pea-wheat silages has increased forage intake and milk yield compared to grass silage (Salawu et al., 2002; Adesogan et al., 2004). In this experiment pea-barley bi-crop silage was studied since in Finland barley harvested for WCS is more digestible than wheat
A previously unobserved conformation for the human Pex5p receptor suggests roles for intrinsic flexibility and rigid domain motions in ligand binding
BACKGROUND: The C-terminal tetratricopeptide (TPR) repeat domain of Pex5p recognises proteins carrying a peroxisomal targeting signal type 1 (PTS1) tripeptide in their C-terminus. Previously, structural data have been obtained from the TPR domain of Pex5p in both the liganded and unliganded states, indicating a conformational change taking place upon cargo protein binding. Such a conformational change would be expected to play a major role both during PTS1 protein recognition as well as in cargo release into the peroxisomal lumen. However, little information is available on the factors that may regulate such structural changes. RESULTS: We have used a range of biophysical and computational methods to further analyse the conformational flexibility and ligand binding of Pex5p. A new crystal form for the human Pex5p C-terminal domain (Pex5p(C)) was obtained in the presence of Sr(2+ )ions, and the structure presents a novel conformation, distinct from all previous liganded and apo crystal structures for Pex5p(C). The difference relates to a near-rigid body movement of two halves of the molecule, and this movement is different from that required to reach a ring-like conformation upon PTS1 ligand binding. The bound Sr(2+ )ion changes the dynamic properties of Pex5p(C) affecting its conformation, possibly by making the Sr(2+)-binding loop – located near the hinge region for the observed domain motions – more rigid. CONCLUSION: The current data indicate that Pex5p(C) is able to sample a range of conformational states in the absence of bound PTS1 ligand. The domain movements between various apo conformations are distinct from those involved in ligand binding, although the differences between all observed conformations so far can be characterised by the movement of the two halves of Pex5p(C) as near-rigid bodies with respect to each other
Inverse Modeling for MEG/EEG data
We provide an overview of the state-of-the-art for mathematical methods that
are used to reconstruct brain activity from neurophysiological data. After a
brief introduction on the mathematics of the forward problem, we discuss
standard and recently proposed regularization methods, as well as Monte Carlo
techniques for Bayesian inference. We classify the inverse methods based on the
underlying source model, and discuss advantages and disadvantages. Finally we
describe an application to the pre-surgical evaluation of epileptic patients.Comment: 15 pages, 1 figur
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