107 research outputs found
ø-threshold and ø-tolerance chain graphs
AbstractIn this paper we introduce a class of graphs called ø-threshold graphs which generalize threshold graphs. These graphs are studied for various functions ø that include “max” and “min” as special cases. The graphs are then shown to fit into the more general setting of ø-tolerance intersection graphs previously introduced by Jacobson, McMorris, and Mulder. Finally, ø-tolerance chain graphs are studied for the same functions ø mentioned above
Adding Isolated Vertices Makes some Online Algorithms Optimal
An unexpected difference between online and offline algorithms is observed.
The natural greedy algorithms are shown to be worst case online optimal for
Online Independent Set and Online Vertex Cover on graphs with 'enough' isolated
vertices, Freckle Graphs. For Online Dominating Set, the greedy algorithm is
shown to be worst case online optimal on graphs with at least one isolated
vertex. These algorithms are not online optimal in general. The online
optimality results for these greedy algorithms imply optimality according to
various worst case performance measures, such as the competitive ratio. It is
also shown that, despite this worst case optimality, there are Freckle graphs
where the greedy independent set algorithm is objectively less good than
another algorithm. It is shown that it is NP-hard to determine any of the
following for a given graph: the online independence number, the online vertex
cover number, and the online domination number.Comment: A footnote in the .tex file didn't show up in the last version. This
was fixe
Pharmacokinetics and bioavailability of doxycycline in fasted and nonfasted broiler chickens
The pharmacokinetics and the influence of food on the kinetic profile and bioavailability of doxycycline was studied after a single intravenous (i.v.) and oral dose of 10.0 mg/kg body weight in 7-week-old broiler chickens. Following i.v. administration the drug was rapidly distributed in the body with a distribution half-life of 0.21 ± 0.01 h. The elimination half-life of 6.78 ± 0.06 h was relatively long and resulted from both a low total body clearance of 0.139 ± 0.007 L/h·kg and a large volume of distribution of 1.36 ± 0.06 L/kg. After oral administration to fasted chickens, the absorption of doxycycline was quite fast and substantial as shown by the absorption half-life of 0.39 ± 0.03 h, the maximal plasma concentration of 4.47 ± 0.16 —g/mL and the time to reach the Cmax of 1.73 ± 0.06 h. The distribution and the final elimination of the drug were slower than after i.v. administration. The absolute bioavailability was 73.4 ± 2.5%. The presence of food in the intestinal tract reduced and extended the absorption (t1/2a = 1.23 ± 0.21 h; Cmax = 3.07 ± 0.23 µg/mL; tmax = 3.34 ± 0.21 h). The absolute bioavailability was reduced to 61.1% ± 4.4%
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