Influence of pore size distribution on drying behaviour of porous media by a continuous model

Bundle of capillaries, drying kinetics, continuous model, relative permeability, capillary pressure, control volume method

Modelling the influence of microstructure on elastic properties and tensile damage behaviour of Mo-base silicide alloys

Mo-Si-B alloys, Real microstructures, Voronoi structures, Microstructural characterization, Modelling and finite element simulations, Effective material properties, Damage and Crack growth, tensile strength, fracture toughness

Simulation of the deformation behaviour of two-phase composites

Two-phase polycrystal, elasto-viscoplastic material model, heterogeneity, anisotropy, flow behaviour, crystallographic texture, strain field

Numerical investigation of micro and macro mechanical behaviour of granular media via a discrete element approach

Magdeburg, Univ., Fak. für Mathematik, Diss., 2009

Reproducibility and Reliability of the Quality of Life Questionnaire in Patients With Atrial Fibrillation

Abstract Background: Studies have shown the impact of atrial fibrillation (AF) on the patients' quality of life. Specific questionnaires enable the evaluation of relevant events. We previously developed a questionnaire to assess the quality of life of patients with AF (AFQLQ version 1), which was reviewed in this study, and new domains were added. Objective: To demonstrate the reproducibility of the AFQLQ version 2 (AFQLQ v.2), which included the domains of fatigue, illness perception and well-being. Methods: We applied 160 questionnaires (AFQLQ v.2 and SF-36) to 40 patients, at baseline and 15 days after, to measure inter- and intraobserver reproducibility. The analysis of quality of life stability was determined by test-retest, applying the Bartko intraclass correlation coefficient (ICC). Internal consistency was assessed by Cronbach's alpha test. Results: The total score of the test-retest (n = 40) had an ICC of 0.98 in the AFQLQ v.2, and of 0.94 in the SF36. In assessing the intra- and interobserver reproducibility of the AFQLQ v.2, the ICC reliability was 0.98 and 0.97, respectively. The internal consistency had a Cronbach's alpha coefficient of 0.82, compatible with good agreement of the AFQLQ v.2. Conclusion: The AFQLQ v.2 performed better than its previous version. Similarly, the domains added contributed to make it more comprehensive and robust to assess the quality of life of patients with AF.

Impact of casting parameters and chemical composition on the solidification behaviour of Al-Si-Cu hypoeutectic alloy

Magdeburg, Univ., Fak. für Maschinenbau, Diss., 2010

Existence, multiplicity and behaviour of solutions of some elliptic differential equations of higher order

Magdeburg, Univ., Fak. für Mathematik, Diss., 2009

Visual recognition systems in a car passenger compartment with the focus on facial driver identification

Magdeburg, Univ., Fak. für Informatik, Diss., 2014

Targeted search engines for children : search user interfaces and information-seeking behaviour

Magdeburg, Univ., Fak. für Informatik, Diss., 2015

Oviposition behaviour of Gryon gallardoi (Hymenoptera, Scelionidae) on eggs of different ages of Spartocera dentiventris (Hemiptera, Coreidae)

The oviposition behaviour of Gryon gallardoi (Brèthes, 1914) on eggs of Spartocera dentiventris Mendonça Jr. (Berg, 1884) of different ages (2, 3, 4, 5, 6, 7, 8 and 12 days) was investigated. Groups of 12 eggs of each age were exposed to single females of G. gallardoi, and the oviposition behaviour was recorded under a stereomicroscope for two hours. Ten replicates were used for each age. In order to identify the moment the parasitoid egg was released inside the host, 1-day old eggs of S. dentiventris were exposed to G. gallardoi females, and the oviposition was interrupted at intervals of 20, 40, 60, 80, 100, 120, 140 and 160s after ovipositor insertion had initiated. Five behavioural steps were recorded: drumming, ovipositor insertion, marking, walking and resting. The average drumming and ovipositor insertion times increased with the host age (P<0.01). Ovipositor insertion usually occurred next to the longitudinal extremities of the host eggs. Marking took on average 19.5 ± 0.7s, and as walking and resting, was not affected by host age. Self-parasitism behaviour was observed in only 13.8 ± 2.3% of the eggs, being more evident with increasing patch depletion (reduction in non-parasitized eggs in the egg group, P<0.01), again with no variation due to changes in host egg age. For all ages tested, self-parasitized host eggs were less frequently contacted and accepted than non-parasitized ones (P<0.01). The parasitoid egg was released 137.0 ± 3.7s after ovipositor insertion. Spartocera dentiventris egg condition can lead to parasitoid behavioural changes, especially during the process of host choice and discrimination.

The optimal behaviour of firms facing stochastic costs

This paper aims at assessing the optimal behavior of a firm facing stochastic costs of production. In an imperfectly competitive setting, we evaluate to what extent a firm may decide to locate part of its production in other markets different from which it is actually settled. This decision is taken in a stochastic environment. Portfolio theory is used to derive the optimal solution for the intertemporal profit maximization problem. In such a framework, splitting production between different locations may be optimal when a firm is able to charge different prices in the different local markets.

Human capital in export-based internationalisation. "Managerial determinants and their influence upon the export behaviour of the firm: four case-studies of catalan exporting SMEs"

Export activities are a major source of economic growth and are considered important both at the national level and for individual businesses. Moreover, in the case of SMEs, they gain particular relevance, exporting being the most common foreign market entry mode for these firms. The decision maker’s role in the export activity is crucial, particularly in the case of SMEs. However, the extant literature on internationalization is characterized by a lack of consensus among scholars as to what constitutes the managerial factor in determining exporting. Therefore, this study focuses on the following issue: Which are the decision maker’s characteristics and perceptions that may influence the export behaviour of Catalan SMEs? To address this question a multiple case study method is applied across four Catalan exporting SMEs. The methodology chosen for analysing the empirical data is relying on the proposition testing approach while the investigation is conducted including both within and cross-case analysis. The findings show that high educational level, language skills, high risk tolerance, innovativeness as well as strongly perceived export stimuli as compared to low and easy to overcome export barriers positively influence the export involvement and development of SMEs. The study provides further insights into the research topic by jointly studying managerial characteristics and perceptions. Additionally, the majority of research on exporting topics has been carried out in the USA, so there is a clear need of investigation in the field in other countries, moreover in Spain where the exporting activities have not been as widely studied.

Daily physical activities and sports in adult survivors of childhood cancer and healthy controls: a population-based questionnaire survey.

BACKGROUND: Healthy lifestyle including sufficient physical activity may mitigate or prevent adverse long-term effects of childhood cancer. We described daily physical activities and sports in childhood cancer survivors and controls, and assessed determinants of both activity patterns. METHODOLOGY/PRINCIPAL FINDINGS: The Swiss Childhood Cancer Survivor Study is a questionnaire survey including all children diagnosed with cancer 1976-2003 at age 0-15 years, registered in the Swiss Childhood Cancer Registry, who survived ≥5 years and reached adulthood (≥20 years). Controls came from the population-based Swiss Health Survey. We compared the two populations and determined risk factors for both outcomes in separate multivariable logistic regression models. The sample included 1058 survivors and 5593 controls (response rates 78% and 66%). Sufficient daily physical activities were reported by 52% (n = 521) of survivors and 37% (n = 2069) of controls (p<0.001). In contrast, 62% (n = 640) of survivors and 65% (n = 3635) of controls reported engaging in sports (p = 0.067). Risk factors for insufficient daily activities in both populations were: older age (OR for ≥35 years: 1.5, 95CI 1.2-2.0), female gender (OR 1.6, 95CI 1.3-1.9), French/Italian Speaking (OR 1.4, 95CI 1.1-1.7), and higher education (OR for university education: 2.0, 95CI 1.5-2.6). Risk factors for no sports were: being a survivor (OR 1.3, 95CI 1.1-1.6), older age (OR for ≥35 years: 1.4, 95CI 1.1-1.8), migration background (OR 1.5, 95CI 1.3-1.8), French/Italian speaking (OR 1.4, 95CI 1.2-1.7), lower education (OR for compulsory schooling only: 1.6, 95CI 1.2-2.2), being married (OR 1.7, 95CI 1.5-2.0), having children (OR 1.3, 95CI 1.4-1.9), obesity (OR 2.4, 95CI 1.7-3.3), and smoking (OR 1.7, 95CI 1.5-2.1). Type of diagnosis was only associated with sports. CONCLUSIONS/SIGNIFICANCE: Physical activity levels in survivors were lower than recommended, but comparable to controls and mainly determined by socio-demographic and cultural factors. Strategies to improve physical activity levels could be similar as for the general population.

Five-day plan for smoking cessation using group behaviour therapy.

The "Five-Day Plan to Stop Smoking" (FDP) is an educational group technique for smoking cessation. We studied a cohort of 123 smokers (55 men, 68 women, mean age 42 years) who participated in 11 successive FDP sessions held in Switzerland between 1995 and 1998 and who were followed up for at least 12 months by telephone or direct interview. Overall, 102 of the 123 subjects (83%) had stopped smoking by the end of the FDP, and self-declared smoking cessation rate was 25% after one year. The following factors potentially associated with outcome were studied: age, sex, smoking habit duration, cigarettes per day, Fagerström Test for Nicotine Dependence (FTND), group size, and medical presence among the group leaders. Smoking habit duration was the only variable which showed a statistically significant association with success: the rate of smoking cessation was higher among patients who had smoked for less than 20 years (34.7% vs. 18.9%, p = 0.049). Stress was the most common cause of relapse. The FDP appears to be an effective smoking cessation therapy. Propositions are made in order to improve the success rate of future sessions.

A simple genetic basis for complex social behaviour mediates widespread gene expression differences.

A remarkable social polymorphism is controlled by a single Mendelian factor in the fire ant Solenopsis invicta. A genomic element marked by the gene Gp-9 determines whether workers tolerate one or many fertile queens in their colony. Gp-9 was recently shown to be part of a supergene with two nonrecombining variants, SB and Sb. SB/SB and SB/Sb queens differ in how they initiate new colonies, and in many physiological traits, for example odour and maturation rate. To understand how a single genetic element can affect all these traits, we used a microarray to compare gene expression patterns between SB/SB and SB/Sb queens of three different age classes: 1-day-old unmated queens, 11-day-old unmated queens and mated, fully reproductive queens collected from mature field colonies. The number of genes that were differentially expressed between SB/SB and SB/Sb queens of the same age class was smallest in 1-day-old queens, maximal in 11-day-old queens and intermediate in reproductive queens. Gene ontology analysis showed that SB/SB queens upregulate reproductive genes faster than SB/Sb queens. For all age classes, genes inside the supergene were overrepresented among the differentially expressed genes. Consistent with the hypothesized greater number of transposons in the Sb supergene, 13 transposon genes were upregulated in SB/Sb queens. Viral genes were also upregulated in SB/Sb mature queens, consistent with the known greater parasite load in colonies headed by SB/Sb queens compared with colonies headed by SB/SB queens. Eighteen differentially expressed genes between reproductive queens were involved in chemical signalling. Our results suggest that many genes in the supergene are involved in regulating social organization and queen phenotypes in fire ants.