The Greedy Independent Set in a Random Graph with Given Degrees

We analyse the size of an independent set in a random graph on n vertices with specified vertex degrees, constructed via a simple greedy algorithm: order the vertices arbitrarily, and, for each vertex in turn, place it in the independent set unless it is adjacent to some vertex already chosen. We find the limit of the expected proportion of vertices in the greedy independent set as (the jamming constant), expressed as an integral whose upper limit is defined implicitly, valid whenever the second moment of a random vertex degree is uniformly bounded. We further show that the random proportion of vertices in the independent set converges in probability to the jamming constant as . The results hold under weaker assumptions in a random multigraph with given degrees constructed via the configuration model. © 2017 Wiley Periodicals, Inc. Random Struct. Alg., 51, 565–586, 2017     

On String Graph Limits and the Structure of a Typical String Graph

We study limits of convergent sequences of string graphs, that is graphs with an intersection representation consisting of curves in the plane. We use these results to study the limiting behavior of a sequence of random string graphs. We also prove similar results for several related graph classes.     

Stress-strain relationships for spruce wood: Influence of strain rate,moisture content and loading direction

The influence of strain rate, moisture content and loading direction on the stress-strain relationships for spruce wood has been investigated. The strain rates were approximately 8×10⁻³ s⁻¹, 17s⁻¹ and 1000 s⁻¹, and the states of moisture content were those corresponding to oven dry, fiber saturated and fully saturated. Compressive loads were applied along the principal directions of the stem of the tree, i.e., radially, tangentially and axially. The low and medium strain-rate tests were performed with the aid of a servohydraulic testing machine, while the high strain-rate tests were carried out using the split Hopkinson pressure bar (SHPB) technique. Magnesium or steel bars were used in the different SHPB tests in order to reduce impedance mismatch for the different directions of the wood specimens. The strain rate was found to have large influence on the behavior of the wood, especially under the condition of full saturation, where water transport in the deforming specimen is of major importance.     

Vocal Behavior and Vocal Loading Factors for Preschool Teachers at Work Studied with Binaural DAT Recordings

Preschool teachers are at risk for developing voice problems such as vocal fatigue and vocal nodules. The purpose of this report was to study preschool teachers' voice use during work. Ten healthy female preschool teachers working at daycare centers (DCC) served as subjects. A binaural recording technique was used. Two microphones were placed on both sides of the subject's head, at equal distance from the mouth, and a portable DAT recorder was attached to the subject's waist. Recordings were made of a standard reading passage before work (baseline) and of spontaneous speech during work. The recording technique allowed separate analyses of the level of the background noise, and of the subjects' voice sound pressure level, mean fundamental frequency, and total phonation time. Among the results, mean background noise level for the ten DCCs was 76.1 dBA (range 73.0-78.2), which is more than 20 dB higher than what is recommended where speech communication is important (50-55 dBA). The subjects spoke on an average of 9.1 dB louder (p < 0.0001), and with higher mean fundamental frequency (247 Hz) during work as compared to the baseline (202 Hz) (p < 0.0001). Mean phonation time for the group was 17%, which was considered high. It was concluded that preschool teachers do have a highly vocally demanding profession. Important steps to reduce the vocal loading for this occupation would be to decrease the background noise levels and include pauses so that preschool teachers can rest their voices.     

Adsorption of polar lipids at the water-oil interface

Dietary fat has long been recognized as an essential component in nutrition. However, most of the lipids present in food need to be converted into more bioavailable compounds. Lipases have a crucial role in converting triglycerides into more polar lipids with increased water solubility and a tendency to form micelles. However, the surface active molecules generated by lipolysis may have a detrimental effect on the interfacial biocatalysis. In the present work we evaluate the interfacial properties of lipase-generated molecules during fat digestion. By using the pendant drop technique we assessed the amphiphilic character of fatty acid salts, monoglycerides, and diglycerides as individual surfactants and mixtures. The experimental results are fitted with a mathematical model, which assists in the determination of the interfacial properties of the surfactants. Our results show that monoglycerides have considerably higher interfacial activity than fatty acid salts and diglycerides. Therefore, the interface will soon be dominated by monoglycerides. The pH dependency of the interfacial activity of fatty acids is also explored in the current work. We believe that our results can contribute to a better understanding of the complex interfacial phenomena occurring during fat digestion.     

Ameisensäure

Analytical and Bioanalytical Chemistry -     

Die titrimetrische Bestimmung von Kaliumxanthogenat

Ohne Zusammenfassung     

On the size of identifying codes in binary hypercubes

In this paper, we consider identifying codes in binary Hamming spaces Fn, i.e., in binary hypercubes. The concept of (r,??)-identifying codes was introduced by Karpovsky, Chakrabarty and Levitin in 1998. Currently, the subject forms a topic of its own with several possible applications, for example, to sensor networks.Let us denote by the smallest possible cardinality of an (r,??)-identifying code in Fn. In 2002, Honkala and Lobstein showed for ?=1 that