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Substantial Flexibility (substantial + flexibility)

Distribution by Scientific Domains

Life Sciences	50%
Chemistry	50%

Selected Abstracts

Estimating natal dispersal movement rates of female European ducks with multistate modelling

JOURNAL OF ANIMAL ECOLOGY, Issue 6 2003
Peter Blums
Summary 1We used up to 34 years of capture,recapture data from about 22 100 new releases of day-old female ducklings and multistate modelling to test predictions about the influence of environmental, habitat and management factors on natal dispersal probability of three species of ducks within the Engure Marsh, Latvia. 2The mean natal dispersal distances were very similar (c. 0·6,0·7 km) for all three species and were on average 2·7 times greater than breeding dispersal distances recorded within the same study system. 3We were unable to confirm the kinship hypothesis and found no evidence that young first-nesting females nested closer to their relatives (either mother or sister) than to the natal nest. 4Young female northern shovelers, like adults, moved from small islands to the large island when water level was high and vice versa when water level was low before the construction of elevated small islands. Movement probabilities between the two strata were much higher for young shovelers than adults, suggesting that young birds had not yet developed strong fidelity to the natal site. Movements of young female tufted ducks, unlike those of shovelers, were not dependent on water level fluctuations and reflected substantial flexibility in choice of first nesting sites. 5Data for young birds supported our earlier conclusion that common pochard nesting habitats in black-headed gull colonies were saturated during the entire study period. Young females, like the two adult age groups, moved into and out of colonies with similar probability. Fidelity probability of female pochards to each stratum increased with age, being the lowest (0·62) for young (DK) females, intermediate (0·78) for yearlings (SY) and the highest (0·84) for adult (ASY) females. 6Young female tufted ducks, like adults, showed higher probabilities of moving from islands to emergent marshes when water levels were higher both before and after habitat management. The relationship between the spring water levels and movement was much weaker for young females than for adults. 7Young female diving ducks exhibited much stronger (compared to adults) asymmetric movement with respect to proximity to water, with higher movement probabilities to near-water locations than away from these locations. 8Local survival of day-old ducklings during the first year of life was time-specific and very low (means for different strata/states 0·01,0·08) because of high rates of emigration and prefledging mortality. [source]

Analysis and control of heteroazeotropic batch distillation

AICHE JOURNAL, Issue 4 2005
S. Skouras
Abstract The separation of close-boiling and azeotropic mixtures by heterogeneous azeotropic distillation is addressed in batch columns. Both a common rectifier and a multivessel batch column are considered. Theoretical and graphical analyses of the process are presented for both column configurations and different separation strategies are presented. A simple control scheme is proposed for the practical operation of the columns, the implementation of different separation strategies and the realization of the final results. Dynamic simulations for mixtures classified under Serafimov's topological classes 2.0-2b and 3.1-2 verify the theoretical findings. The results show that heteroazeotropic batch distillation exhibits substantial flexibility. The column profile can be totally restored during the process and lie in regions different from those of the initial feed. The still path can cross distillation boundaries and the still product does not have to be the stable node of the feed region. Such results cannot be obtained by homogeneous azeotropic batch distillation. © 2005 American Institute of Chemical Engineers AIChE J, 2005 [source]

DNA vaccination against tumors

THE JOURNAL OF GENE MEDICINE, Issue 1 2005
Gérald J. Prud'homme
Abstract DNA vaccines have been used to generate protective immunity against tumors in a variety of experimental models. The favorite target antigens have been those that are frequently expressed by human tumors, such as carcinoembryonic antigen (CEA), ErbB2/neu, and melanoma-associated antigens. DNA vaccines have the advantage of being simple to construct, produce and deliver. They can activate all arms of the immune system, and allow substantial flexibility in modifying the type of immune response generated through codelivery of cytokine genes. DNA vaccines can be applied by intramuscular, dermal/epidermal, oral, respiratory and other routes, and pose relatively few safety concerns. Compared to other nucleic acid vectors, they are usually devoid of viral or bacterial antigens and can be designed to deliver only the target tumor antigen(s). This is likely to be important when priming a response against weak tumor antigens. DNA vaccines have been more effective in rodents than in larger mammals or humans. However, a large number of methods that might be applied clinically have been shown to ameliorate these vaccines. This includes in vivo electroporation, and/or inclusion of various immunostimulatory molecules, xenoantigens (or their epitopes), antigen-cytokine fusion genes, agents that improve antigen uptake or presentation, and molecules that activate innate immunity mechanisms. In addition, CpG motifs carried by plasmids can overcome the negative effects of regulatory T cells. There have been few studies in humans, but recent clinical trials suggest that plasmid/virus, or plasmid/antigen-adjuvant, prime-boost strategies generate strong immune responses, and confirm the usefulness of plasmid-based vaccination. Copyright © 2004 John Wiley & Sons, Ltd. [source]

Domain,Domain Interactions in the Iterative Type I Polyketide Synthase ATX from Aspergillus terreus

CHEMBIOCHEM, Issue 8 2008
Tomomi Moriguchi
Analyzing ATX mutants: ATX, a 6-methylsalicylic acid synthase from Aspergillus terreus, has five catalytic domains in its monomer and forms a homotetramer. Coexpression of inactive ATX catalytic domain mutants in yeast showed that ATX activity was reconstituted by all combinations of the domain mutants, suggesting that the five catalytic domains could interact with each other with substantial flexibility to carry out 6-methylsalicylic acid synthesis. [source]