Counting Linear Extensions: Parameterizations by Treewidth.

We consider the -complete problem of counting the number of linear extensions of a poset ; a fundamental problem in order theory with applications in a variety of distinct areas. In particular, we study the complexity of parameterized by the well-known decompositional parameter treewidth for two natural graphical representations of the input poset, i.e.

Solving Problems on Graphs of High Rank-Width.

A modulator in a graph is a vertex set whose deletion places the considered graph into some specified graph class. The cardinality of a modulator to various graph classes has long been used as a structural parameter which can be exploited to obtain fixed-parameter algorithms for a range of hard problems. Here we investigate what happens when a graph contains a modulator which is large but "well-structured" (in the sense of having bounded rank-width).

[The effect of brilliant cresyl blue on erythrocyte degeneration in patients after acute stroke].

The authors investigated the disintegration of red cells by the action of brilliant cresyl blue in patients after an acute cerebrovascular attack and compared them with the disintegration in blood donors. In the patients the disintegration was assessed within 24 hours after the attack and after one year. The disintegration was assessed in two incubation solutions i.

[Changes in circulation of the blood in cerebral arteries in relation to age].

The authors examined 12 people under 40 years and 12 above 40 years, mostly healthy volunteers. They investigated the rate of blood flow in the median cerebral artery after compression of the homolateral and contralateral internal carotid. They found that in more advanced age the rate of flow in the mentioned arteries is significantly reduced.

[Cerebral circulation using transcranial and extracranial doppler ultrasonography in a patient with vertigo and ischemia in the area of the brain stem].

The authors examined 32 patients with vertigo, 17 patients with focal ischaemia of the brain stem and 24 patients without signs of affections of the central nervous system by transcranial and extracranial Doppler ultrasonography. They measured the flow velocity in the basilar artery (BA), in the intracranial portion of the vertebral artery (VA) and in the extracranial portion of the internal carotid artery (ICA). In patients with vertigo they investigated functional and organic changes in the area of the cervical spine.