We consider the problem of assigning wavelengths to demands in an optical network of m links. We assume that the route of each demand is fixed and the number of wavelengths available on a fiber is some parameter μ. Our aim is to minimize the maximum ratio between the number of fibers deployed on a link e and the number of fibers required on the same link e when wavelength assignment is allowed ...

We study the Independent Set problem in H-free graphs, i.e., graphs excluding some fixed graph H as an induced subgraph. prove several inapproximability results both for polynomial-time and parameterized algorithms. Halldórsson [SODA 1995] showed that every $$\delta >0$$ has a $$(\frac{d-1}{2}+\delta )$$ -approximation algorithm $$K_{1,d}$$ -free graphs. extend this result by showing $$K_{a,b}$...

BACKGROUND The percentage of hypochromic red blood cells (RBC), defined as those with a cellular haemoglobin < 28 g/dl has been suggested to be a sensitive marker of functional iron deficiency in maintenance haemodialysis (HD) patients. Thus, during rHuEpo therapy an increase in hypochromic RBC to > 10% would indicate that more intensive iron supplementation may be required. METHODS We invest...

In contrast to deterministic or nondeterministic computation, it is a fundamental open problem in randomized computation how to separate diierent ran-domized time classes (at this point we do not even know how to separate linear randomized time from O(n log n) randomized time) or how to compare them relative to corresponding deterministic time classes. In other words we are far from understandi...

The most important biothiols include glutathione, homocysteine (HCY), cysteine and proteins. The aim of the presented study was to evaluate the influence of lead on the biothiol turnover--the concentration of HCY and protein sulfhydryl groups (P-SH) in the serum and reduced glutathione (G-SH) in erythrocytes--in individuals (employees of metal works) exposed to lead and to evaluate its probable...

Hemocytometric parameters like red blood cell (RBC) count, mean red blood cell volume (MCV), reticulocyte count, red blood cell distribution width (RDW-SD) and zinc protoporphyrin (ZPP) are frequently established for discrimination between iron-deficiency anemia and thalassemia in subjects with microcytic erythropoiesis. However, no single marker or combination of tests is optimal for discrimin...

compared to extraintestinal disease complications such as arthritis or osteopathy, anaemia in IBD has received little attention. Anaemia is, however, the most common systemic manifestation of IBD 1,2 In a recent review by Gisbert and Gomollón, the prevalence of anaemia in patients with IBD ranged from 16% to 74%, varying from 16% outpatients to 68% in hospitalised patients2. Goodhand et al.3 de...

Previous studies of the associations of measures of occupational lead exposure with measures of semen quality and infertility among male workers have produced conflicting results. The current study was undertaken to examine these associations among a population of workers with a broad range of measures of current and historical lead exposure. Ninety-seven lead-exposed workers from a South Afric...

BACKGROUND Exposure to lead (Pb) in environmental and occupational settings continues to be a serious public health problem and may pose an elevated risk of genetic damage. OBJECTIVES The aim of this study was to assess the level of oxidative stress and DNA damage in subjects occupationally exposed to lead. MATERIAL AND METHODS We studied a population of 78 male workers exposed to lead in a...

The time-constrained packet routing problem is to schedule a set of packets to be transmitted through a multinode network, where every packet has a source and a destination (as in traditional packet routing problems) as well as a release time and a deadline. The objective is to schedule the maximum number of packets subject to deadline constraints. This problem is studied in [1], where it is sh...