Characterization of water in bacterial cellulose using dielectric spectroscopy and electron microscopy

It is shown that only 10% of the 99 wt% water present in bacterial cellulose (BC) gels, produced by Acetobacter xylinum, behave like free bulk water; the majority of the water molecules in the gels is more or less tightly bound to the cellulose. The magnitude of the diffusion coefficients of ions transported in the water phase of the BC gels as well as the information contained in freeze fracture transmission electron microscopic images of the gel structures indicates that the bulk-like water is confined in “lakes” rather than forming a continuous phase throughout the gel. Water desorption isotherms suggest that these “lakes” decrease in size with increasing oxygen concentration used during the biosynthesis process of the gels.     

Knowledge network hubs and measures of research impact, science structure, and publication output in nanostructured solar cell research

This study on co-authorship networks in the area of nanostructured solar cells aims to contribute to a further understanding of the use of research evaluation measures of science output, impact and structure in an emerging research field. The study incorporates quantitative bibliometric methods of analysis and social network analysis in combination with a qualitative case study research approach. Conclusions drawn from the results emphasise, firstly, the importance of distinguishing between early and later phases of the evolution of a novel research field, and secondly, the application of a systemic view on learning processes and knowledge diffusion in a science-based technology field.     

Flow Properties of Spices Measured with Powder Flow Tester and Ring Shear Tester-XS

Due to the importance of powder flow properties and the variety of available measuring methods, several studies were published regarding the comparison of different flow properties testers. Within this work, a ring shear tester from Dr. Dietmar Schulze and a powder flow tester from Brookfield Engineering Laboratories Inc. were compared for cumin (Cuminum cyminum L.), oregano (Origanum vulgare), and onion (Allium cepa) powder and granules. The spices showed similar flow behavior from both methods. Flow function plots and effective angle of internal friction measurements indicated contiguous trends and showed that the methods were comparable.     

Infant-feeding practices and beliefs about complementary feeding among low-income Brazilian mothers: a qualitative study

BACKGROUND: Breastfeeding and weaning practices are important determinants of growth and development not only in infancy but also later in life. OBJECTIVE: To describe infant-feeding practices and beliefs about complementary feeding among low-income Brazilian mothers. METHODS: Qualitative methods included focus group discussions with low-income mothers enrolled in a Family Health/Community Health Workers program in Ceará, Northeast Brazil. RESULTS: Breastfeeding is widely practiced in this area, and overall, mothers are knowledgeable about the benefits of breastfeeding for their infants and themselves. Practices of prolonged breastfeeding and delayed supplementation of infants with semisolid foods emerged as a problem among very poor women. In addition, the results showed common problems related to complementary feeding practices, such as the early introduction of solid foods and the use of expensive commercial cereals and formula for weaning. Cultural factors and taboos appeared to have an important influence on mothers' infant-feeding practices and eating patterns of their children. CONCLUSIONS: The results have implications for the design of breastfeeding promotion and interventions to improve complementary feeding. Improvements of the national Food Grant Program are also suggested, which are needed by low-income mothers to improve their infant-feeding practices.     

Gender and productivity differentials in science

The paper presents the results of an examination of gender differences in scientific productivity on a sample of 840 respondents, half the young scientific population in Croatia. In the last decade gender differences in the scientific productivity of young researchers have increased, which may be the result of introducing a more competitive scientific system. Young female researchers publish an average of two scientific papers less than their male counterparts in five years, and their publications reach 70.6% of males" publication productivity in the same period. In the case of both sexes, about 15% researchers publish about half of all research papers, but even the most productive women publish less than their male counterparts Socio-demographic, educational and qualificational predictors contribute more or less equally to the number of scientific publications by women and men. It is not until we introduce structural variables that a strong sex differentiation appears because these factors are much more powerful in explaining the production of women. They show that female scientists" publication productivity is more strongly influenced by their position in the social organization of science. There are also considerable sex differences in the case of individual productivity predictors. International contacts determine the number of papers by female scientists most of all. Attendance at scientific conferences abroad is the most powerful predictor of male productivity, too, but reviewing colleagues" papers and academic degree are also very important. This revised version was published online in June 2006 with corrections to the Cover Date.     

Learning at work: competence development or competence-stress

Changes in work and the ways in which it is carried out bring a need for upgrading workplace knowledge, skills and competencies. In today's workplaces, and for a number of reasons, workloads are higher than ever and stress is a growing concern (Health Risk Soc. 2(2) (2000) 173; Educat. Psychol. Meas. 61(5) (2001) 866). Increased demand for learning brings a risk that this will be an additional stress factor and thus a risk to health. Our research study is based on the control-demand-support model of Karasek and Theorell (Health Work: Stress, Productivity and the Reconstruction of Working Life, Basic Books/Harper, New York, 1990). We have used this model for our own empirical research with the aim to evaluate the model in the modern workplace. Our research enables us to expand the model in the light of current workplace conditions-especially those relating to learning. We report empirical data from a questionnaire survey of working conditions in two different branches of industry. We are able to define differences between companies in terms of working conditions and competence development. We describe and discuss the effects these conditions have on workplace competence development. Our research results show that increased workers' control of the learning process makes competence development more stimulating, is likely to simplify the work and reduces (learning-related) stress. It is therefore important that learning at work allows employees to control their learning and also allows time for the process of learning and reflection.     

Changes of scientific knowledge production and research productivity in a transitional society

The main objective of this paper is to provide an empirical insight into the changes in the basic characteristics of the knowledge production mode and of scientific productivity in the Croatian research system in the transitional period. Empirical analysis is based on the results of two comparable questionnaire studies. The first survey was conducted in 1990 and the sample covered 921 respondents, while the second survey was conducted in 2004 with a sample of 915 respondents. The central characteristics of the knowledge production mode and of productivity confirm an expected duality: the features that accompany the introduction of a competitive system of research funding and evaluation on the one hand, and the anachronistic and newly acquired peculiarity of the research system on the other. Thus, the gap between the improved scientific performance of the researchers and the conditions in which they work has deepened. Scientific productivity still lags behind the productivity of the (developed) countries. Though Croatian researchers publish less, they follow basic global trends in the structure of publications, especially the rise in foreign and co-authored works.     

Expression Pattern of 5-HT (Serotonin) Receptors during Normal Development of the Human Spinal Cord and Ganglia and in Fetus with Cervical Spina Bifida

The expression of 5-HT (serotonin) receptors (sr) was analyzed in the spinal cord and ganglia of 15 human conceptuses (5–10-weeks), and in the 9-week fetus with spina bifida. We used immunohistochemical method to detect sr-positive, apoptotic (caspase-3) and proliferating (Ki-67) cells, double immunofluorescence for co-localization with protein gene peptide (pgp) 9.5 and GFAP, as well as semiquantification and statistical measurements. Following the neurulation process, moderate (sr1 and sr2) and mild (sr3) expression characterized neuroblasts in the spinal cord and ganglia. During further development, sr1 expression gradually increased in the motoneurons, autonomic and sensory neurons, while sr2 and sr3 increased strongly in floor and roof plates. In the ganglia, sr3 expression increased during limited developmental period, while sr1 and sr2 increased throughout the investigated period. Co-expression of sr/pgp 9.5 characterized developing neurons, while sr/GFAP co-localized in the roof plate. In the spinal cord and ganglia of malformed fetus, weaker sr1 and sr2 and stronger sr3 expression accompanied morphological abnormalities. Anomalous roof plate morphology showed an excess of apoptotic and proliferating cells and increased sr3 expression. Our results indicate a human-species specific sr expression pattern, and the importance of sr1 in neuronal differentiation, and sr2 and sr3 in the control of the roof plate morphogenesis in normal and disturbed development.