The relationship between leadership practices and organisational culture: An education management perspective

The relationship between leadership practice of the principal and school culture was investigated and recommendations on the skills principals need to establish a school culture conducive to teaching and learning are provided. Two standardised questionnaires were used to measure the existing leadership practices and organisational culture in 30 schools. Correlations between leadership practices and school cultures were determined by means of linear regressions and portrayed by scatter plots. It was found that each of the leadership practices tested was positively related to either of the two main elements of organisational culture: sociability or solidarity. The findings provided a sound basis for the appointment of principals able to cultivate a positive school culture.Keywords: correlation; culture; education; leadership; management; organisation; relationshipSouth African Journal of Education Vol. 26 (4) 2006: pp. 609-62

Some recent results in aerospace vehicle trajectory optimization techniques

Algorithms and computation techniques for solving trajectory optimization problem

Gender differences in physical activity and fitness—association with self-reported health and health-relevant attitudes in a middle-aged Swiss urban population

In Switzerland lack of exercise is common. To improve physical exercise in both women and men, campaigns should consider the motivation for physical activity with respect to gender. This study explores the patterns of self-reported sport activity, habitual physical activity and physical fitness, and associated indicators of self-reported health, health-relevant attitudes, and resources in an urban Swiss population. Using the Bern Lifestyle Panel questionnaire, 511 women and 413 men, aged 55-65years, in the German-speaking capital of Switzerland were assessed. From the three surveys carried out from 1996 to 1998, this study used the data from the 1997 survey for a cross-sectional analysis. Women demonstrated a lower prevalence of sport activity than men but a higher prevalence of habitual physical activity. Forty-six percent of the women but 80% of the men reported a high level of fitness. In the logistic regression analysis, sport activity in the women was significantly associated with indicators of health, health-relevant attitudes such as internal and external health locus of control, and social class. Among the men, no association with health-relevant orientation could be found. The probability of habitual physical activity among the women was associated with perceived good health, health-relevant orientation and social class, while related factors among the men were indicators of health. In both women and men, perceived good health was strongly associated with self-reported physical fitness. Additionally, women's fitness was related to perceived disease-related limitation and indicators of health status. The findings indicate a gender-specific distribution of sport activity, habitual physical activity and fitness. Compared to men, physical activity in women is associated more with health-relevant orientation. Along with indicators of health, attention should be paid to both female and male perception of health and self-reported attitudes when there is an attempt to improve physical activity. Since self-reported health status, disease-related limitations, and habitual physical activity, among others, are strongly affected by sociocultural and structural influences, caution should be kept in drawing general conclusions from the finding

Exploring the functional domain and the target of the tetanus toxin light chain in neurohypophysial terminals

The tetanus toxin light chain blocks calcium induced vasopressin release from neurohypophysial nerve terminals. Here we show that histidine residue 233 within the putative zinc binding motif of the tetanus toxin light chain is essential for the inhibition of exocytosis, in the rat. The zinc chelating agent dipicolinic acid as well as captopril, an inhibitor of zinc-dependent peptidases, counteract the effect of the neurotoxin. Synthetic peptides, the sequences of which correspond to motifs present in the cytoplasmic domain of the synaptic vesicle membrane protein synaptobrevin 1 and 2, prevent the effect of the tetanus toxin light chain. Our results indicate that zinc bound to the zinc binding motif constitutes the active site of the tetanus toxin light chain. Moreover they suggest that cleavage of synaptobrevin by the neurotoxin causes the inhibition of exocytotic release of vasopressin from secretory granules

Evaluation of the application of ERTS-1 data to the regional land use planning process

The author has identified the following significant results. Employing simple and economical extraction methods, ERTS can provide valuable data to the planners at the state or regional level with a frequency never before possible. Interactive computer methods of working directly with ERTS digital information show much promise for providing land use information at a more specific level, since the data format production rate of ERTS justifies improved methods of analysis

The Potential Role of Marine Fungi in Plastic Degradation – A Review

Plastic debris has been accumulating in the marine realm since the start of plastic mass production in the 1950s. Due to the adverse effects on ocean life, the fate of plastics in the marine environment is an increasingly important environmental issue. Microbial degradation, in addition to weathering, has been identified as a potentially relevant breakdown route for marine plastic debris. Although many studies have focused on microbial colonization and the potential role of microorganisms in breaking down marine plastic debris, little is known about fungi-plastic interactions. Marine fungi are a generally understudied group of microorganisms but the ability of terrestrial and lacustrine fungal taxa to metabolize recalcitrant compounds, pollutants, and some plastic types (e.g., lignin, solvents, pesticides, polyaromatic hydrocarbons, polyurethane, and polyethylene) indicates that marine fungi could be important degraders of complex organic matter in the marine realm, too. Indeed, recent studies demonstrated that some fungal strains from the ocean, such as Zalerion maritimum have the ability to degrade polyethylene. This mini-review summarizes the available information on plastic-fungi interactions in marine environments. We address (i) the currently known diversity of fungi colonizing marine plastic debris and provide (ii) an overview of methods applied to investigate the role of fungi in plastic degradation, highlighting their advantages and drawbacks. We also highlight (iii) the underestimated role of fungi as plastic degraders in marine habitats

Comparative Evolution of Jupiter and Saturn

We present evolutionary sequences for Jupiter and Saturn, based on new nongray model atmospheres, which take into account the evolution of the solar luminosity and partitioning of dense components to deeper layers. The results are used to set limits on the extent to which possible interior phase separation of hydrogen and helium may have progressed in the two planets. When combined with static models constrained by the gravity field, our evolutionary calculations constrain the helium mass fraction in Jupiter to be between 0.20 and 0.27, relative to total hydrogen and helium. This is in agreement with the Galileo determination. The helium mass fraction in Saturn's atmosphere lies between 0.11 and 0.25, higher than the Voyager determination. Based on the discrepancy between the Galileo and Voyager results for Jupiter, and our models, we predict that Cassini measurements will yield a higher atmospheric helium mass fraction for Saturn relative to the Voyager value.Comment: 18 pages, LaTeX, 4 figures. submitted to ``Planetary and Space Science.'