4,080 research outputs found
A test for connectedness fitted for the blup-procedure
International audienc
Teaching breeding planning for a dual-purpose cattle population by a programmed exercise
International audienc
Computer aids for teaching animal breeding
International audienc
Strong spin-orbit splitting on Bi surfaces
Using first-principles calculations and angle-resolved photoemission, we show
that the spin-orbit interaction leads to a strong splitting of the surface
state bands on low-index surfaces of Bi. The dispersion of the states and the
corresponding Fermi surfaces are profoundly modified in the whole surface
Brillouin zone. We discuss the implications of these findings with respect to a
proposed surface charge density wave on Bi(111) as well as to the surface
screening, surface spin-density waves, electron (hole) dynamics in surface
states, and to possible applications to the spintronics.Comment: 4 pages 2 figure
Relationship between haemodynamic impairment and collateral blood flow in carotid artery disease
Collateral blood flow plays a pivotal role in steno-occlusive internal carotid artery (ICA) disease to prevent irreversible ischaemic damage. Our aim was to investigate the effect of carotid artery disease upon cerebral perfusion and cerebrovascular reactivity and whether haemodynamic impairment is influenced at brain tissue level by the existence of primary and/or secondary collateral. Eighty-eight patients with steno-occlusive ICA disease and 29 healthy controls underwent MR examination. The presence of collaterals was determined with time-of-flight, two-dimensional phase contrast MRA and territorial arterial spin labeling (ASL) imaging. Cerebral blood flow and cerebrovascular reactivity were assessed with ASL before and after acetazolamide. Cerebral haemodynamics were normal in asymptomatic ICA stenosis patients, as opposed to patients with ICA occlusion, in whom the haemodynamics in both hemispheres were compromised. Haemodynamic impairment in the affected brain region was always present in symptomatic patients. The degree of collateral blood flow was inversely correlated with haemodynamic impairment. Recruitment of secondary collaterals only occurred in symptomatic ICA occlusion patients. In conclusion, both CBF and cerebrovascular reactivity were found to be reduced in symptomatic patients with steno-occlusive ICA disease. The presence of collateral flow is associated with further haemodynamic impairment. Recruitment of secondary collaterals is associated with severe haemodynamic impairment
STM observation of electronic wave interference effect in finite-sized graphite with dislocation-network structures
Superperiodic patterns near a step edge were observed by STM on
several-layer-thick graphite sheets on a highly oriented pyrolitic graphite
substrate, where a dislocation network is generated at the interface between
the graphite overlayer and the substrate. Triangular- and rhombic-shaped
periodic patterns whose periodicities are around 100 nm were observed on the
upper terrace near the step edge. In contrast, only outlines of the patterns
similar to those on the upper terrace were observed on the lower terrace. On
the upper terrace, their geometrical patterns gradually disappeared and became
similar to those on the lower terrace without any changes of their periodicity
in increasing a bias voltage. By assuming a periodic scattering potential at
the interface due to dislocations, the varying corrugation amplitudes of the
patterns can be understood as changes in LDOS as a result of the beat of
perturbed and unperturbed waves, i.e. the interference in an overlayer. The
observed changes in the image depending on an overlayer height and a bias
voltage can be explained by the electronic wave interference in the ultra-thin
overlayer distorted under the influence of dislocation-network structures.Comment: 8 pages; 6 figures; Paper which a part of cond-mat/0311068 is
disscussed in detai
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