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We investigate the hardness of approximating the longest path and the longest cycle in directed graphs on n vertices. We show that neither of these two problems can be polynomial time approximated within n(1-epsilon)for any epsilon > 0 unless P = NP. In particular, the result holds for digraphs of constant bounded outdegree that contain a Hamiltonian cycle. Assuming the stronger complexity conject
The European Gaia astrometry mission is due for launch in 2011. Gaia will rely on the proven principles of the ESA Hipparcos mission to create an all-sky survey of about one billion stars throughout our Galaxy and beyond, by observing all objects down to 20 mag. Through its massive measurement of stellar distances, motions and multicolour photometry, it will provide fundamental data necessary for
Patients with contact allergy to sesquiterpene lactones (SLs) are usually hypersensitive to Asteraceae plant products such as herbal teas. The objective of this study was to show sensitizers in chamomile tea by patch testing with thin-layer chromatograms. Tea made from German chamomile was separated by thin-layer chromatography. Strips of the thin-layer chromatograms were used for patch testing SL
Estrogen and progesterone are key regulators of normal breast epithelial cell proliferation and differentiation. They are also involved in the initiation and progression of breast tumorigenesis. Several experimental studies have demonstrated that steroid hormones affect cell cycle proteins associated with tumor initiation and progression. Hormone replacement therapy (HT) is widely used to alleviat
The importance of particular genes in neuronal death following global cerebral ischemia can readily be studied in genetically modified mice provided a reliable model of ischemia is available. For that purpose, we developed a mouse model of global cerebral ischemia that induces consistent damage to different regions of the brain and with a low mortality rate. Twelve minutes of ischemia was induced
A quantitative determination of 2s vacancy lifetimes in surface and bulk atoms of free Ne clusters has been made. While for free atoms the 2s inner-valence hole has a ps lifetime, it reduces to 6+/-1 fs for cluster bulk atoms. For surface atoms, the lifetime is on average longer than 30 fs. The lifetime estimate was obtained from fits of high-resolution photoelectron spectra of Ne clusters. The sh
The relation between supraphysiologic circulating testosterone levels and prostatic diseases is unclear and difficult to study in men. Animal models may be advantageous. Based on a pilot study, testosterone enantate 50 mg (n=12) or 25 mg (n=12) was administered to guinea-pigs intramuscularly every 3 weeks, for either 7 or 14 months. The histopathology of the prostate was described. Epithelial hype
The Klebsiella pneumoniae ozenae KIIIA strain was isolated from the River Rhine soon after a serious mercury pollution episode and was selected for mercury resistance as well as for intergeneric DNA mobilization helper potential. This transfer helper capacity was shown to be related to the presence of a Tn3-like transposable element, Tn5403. Because transposon-mediated fusion was found to be invol
We compared hypnotizability between two samples from different Universities in Sweden. One test was administered in Swedish (University of Skövde) using a translated Swedish version of the HGSHS:A (Bergman, Trenter, & Kallio, 2003). At Lund University, the original English version of the HGSHS:A (Shor & Orne 1962) was used and participants also completed the Inventory Scale of Hypnotic Dep
Aim: This study aims to investigate cardiac structure and function in patients with asymptomatic primary hyperparathyroidism (pHPT) and if there is any relation to severity regarding serum levels of calcium (Ca) and parathyroid hormone. Methods and Results: We consecutively included 50 patients (mean age 62.9 +/- 11 years, 45 women) with clinically diagnosed pHPT. We prospectively recruited 50 hea
We propose a way to estimate a parametric quantile function when the dependent variable, e.g. the survival time, is censored. We discuss one way to do this, transforming the problem of finding the p-quantile for the true, uncensored, survival times into a problem of finding the q-quantile for the observed, censored, times. The q-value involves the distribution of the censoring times, which is unkn
The evolution of cooperation requires benefits of group living to exceed costs. Hence, some components of fitness are expected to increase with increasing group size, whereas others may decrease because of competition among group members. The social spiders provide an excellent system to investigate the costs and benefits of group living: they occur in groups of various sizes and individuals are r
Background and Objectives. From 1994 to 1997 we conducted a population-based, prospective study on intensive therapy in newly diagnosed symptomatic myeloma patients younger than 60 years, comparing their survival to that of a conventionally treated historic population. Long-term results are presented, including the impact of the degree of response on survival and relapse pattern after transplantat
A technique for optical control of the spatial distribution of laser-accelerated ion beams is presented. An ultra-short laser pulse, tightly focused to relativistic intensities on a thin foil target, drives a beam of MeV ions. An auxiliary, nanosecond laser pulse drives a shock and locally deforms the initially flat target prior to the main pulse interaction. By changing the properties of the shoc
