45 research outputs found
“Knowledge Is Power”: A Mixed-Methods Study Exploring Adult Audience Preferences for Engagement and Learning Formats Over 3 Years of a Health Science Festival
© 2015, © 2015 SAGE Publications. Science festivals enable scientists to engage with publics, but format design reflecting different engagement models is contested. This study gathered mixed-methods data over 3 years (2011-2013) from on-site surveys (N = 661) of a health science festival, exploring audience preferences for dissemination or dialogue formats (lectures, discussions, community expo, lab experiments, and day out). Irrespective of time, age–group, or gender, lectures were significantly ranked the main attraction (76.8%), most highly attended (89.1%), and most useful format (83.8%). Thematic analysis revealed five themes exploring nonformal learning motivations for audiences, highlighting that knowledge/understanding acquisition is perceived as empowering greater health literacy
Bioelectrorheological model of the cell. 4. Analysis of the extensil deformation of cellular membrane in alternating electric field.
Analysis of the angular distribution of extensil mechanical stress, sigma e, generated in cytoplasmic membranes by an external oscillating electric field, is presented. Theoretical considerations show that sigma e is directly proportional to the local relative increase in membrane area and/or to the local relative decrease in its thickness. The magnitude of this stress depends on the position of the analyzed point of the membrane in relation to field direction. The maximal value, sigma eo, is reached at the cell "poles." The magnitude of sigma eo depends on electric and geometric parameters (in particular on field frequency) of the system studied. The foregoing analysis can be applied to quantitatively describe the destabilizing effects of the electric field on the cellular membrane, leading to its poration, fusion, and destruction
Bioelectrorheological model of the cell. 3. Viscoelastic shear deformation of the membrane.
An analytical electromechanical model of a spherical cell exposed to an alternating electric field was used to calculate shear stress generated in the cellular membrane. Shape deformation of Neurospora crassa (slime) spheroplasts was measured. Statistical analysis permitted empirical evaluation of creep of the cellular membrane within the range of infinitesimal stress. Final results were discussed in terms of various rheological models
How do observers perceive the depth of a Gothic cathedral interior along with the change of its proportions? Eye tracking survey
Inspiracją do podjęcia badań nad percepcją wnętrza gotyckiego kościoła były rozważania Juliusza Żórawskiego. W artykule zaprezentowano próbę weryfikacji poglądów Profesora dotyczących sposobu zapoznawania się z tą średniowieczną strukturą. Badania przeprowadzono przy użyciu okulografu stacjonarnego, który umożliwiał rejestrację ruchu gałek ocznych obserwatorów. W testach uczestniczyło 142 wolontariuszy, którzy przyglądali się pięciu przygotowanym przez autorów badania wizualizacjom wnętrz katedr francuskich z XII i XIII w. Ilustracje przedstawiały obiekty o różnej wysokości i głębokości. Celem badania było także określenie, dzięki jakim elementom architektonicznym obserwatorzy najchętniej odczytują głębokość nawy głównej wraz ze zmianą jej proporcji.The study of how people perceive an interior of a Gothic church was inspired by ideas of Juliusz Żórawski. The paper presents an attempt at verifying Żórawski’s views concerning people’s reactions to such medieval buildings. The research was carried out by means of a stationary eye tracker, which made it possible to register the movement of eyes of the participants. 142 volunteers took part in the tests. Each of them looked at five different visualizations showing the interiors of French cathedrals from the 12th and the 13th century. The images showed interiors of various height and length. The aim of the research was to determine which architectural elements make it most probable for the observers to perceive the depth of the main aisle when changes are made to the interior’s proportions
Bioelectrorheological model of the cell. 3. Viscoelastic shear deformation of the membrane
Bioelectrorheological model of the cell. 5. Electrodestruction of cellular membrane in alternating electric field.
Recently proposed analysis of the extensil stress developed in a cellular membrane subjected to an alternating electric field (Pawłowski, P., and M. Fikus, 1993. Bioelectrorheological model of the cell. 4. Analysis of the extensil deformation of the membrane in an alternating field. Biophys. J. 65:535-540) was applied in calculations of extensil stress threshold values, sigma eo[d], producing experimentally observed electrodestruction of cells within the frequency range of 7 x 10(1) - 3 x 10(5) Hz. It was shown that the susceptibility (s[d] = 1/sigma eo[d]), of the membrane to this process varies with field frequency and depends on the type of cells. Electrodestruction is facilitated in the 10(5)-Hz field. A rheological hypothesis explaining the experimentally observed dependence of membrane stability on electric field frequency was proposed and successfully tested for two other phenomena: electroporation and electrofusion
Bioelectrorheological model of the cell. VI. Experimental verification of the rheological model of cytoplasmic membrane.
The susceptibility of the Neurospora crassa (slime) cellular membrane to electroporation and electrodestruction in an alternating electric field was further investigated. The results were analyzed according to the dynamic rheological model of the cytoplasmic membrane. Based on an analytical description of membrane susceptibility to electroporation, the rheological parameters of the foregoing process in N. crassa cellular membrane were found: they closely resemble those previously determined for the membranes' destruction. This suggests that both processes are temporally related and are induced within the same structures of the membrane. The dependence of the destruction of the membrane on the time of application and the frequency of the electric field was theoretically predicted and experimentally confirmed
Determination of electric parameters of cell membranes by a dielectrophoresis method.
Marszalek, P., J. J. Zielinsky, and M. Fikus (1989. Bioelectrochem. Bioenerg. 22:289-298) have described a novel design for measuring the complete dielectrophoretic spectrum of a single cell. From the analysis of the dielectrophoretic spectrum, the membrane conductivity, sigma membr, and the membrane dielectric permittivity, epsilon membr, of the cell may be determined according to the theory of dielectrophoresis described by Sauer, F. A. (1985. Interactions between Electromagnetic Field and Cells. A. Chiabrera, C. Nicolini, and H.P. Schwan, editors. Plenum Publishing Corp., New York. 181-202). At Fo, the net force experienced by a single shell sphere in a nonuniform periodic field is zero, and the sphere ceases to move in the field. In other words, at Fo, the effective polarizability, chi eff, of the sphere (the polarizability of sphere minus the polarizability of the medium) is equal to zero. For biological cells in high conductivity medium, e.g., the isotonic saline, sigma membr falls below 2 x 10(-6) S m-1, where Fo becomes insensitive to sigma membr, and the method becomes impractical. In a low conductivity medium, 0.3 M sucrose, sigma membr of cells is generally higher and the method may be applied. Assuming a membrane thickness of 9 nm, epsilon membr of Neurospora crassa slime cells was determined to be in the range of 8.3-9.4 epsilon o, and of myeloma Tib9 to be 9.4 epsilon o, epsilon o being the dielectric permittivity of the free space. The values for the slime cells were compared with values obtained by the dielectric spectroscopy method which measures average values for cells in suspension