The order-disorder transition of the (3x3)Sn/Ge(111) phase

Growing attention has been drawn in the past years to the \alpha-phase (1/3 monolayer) of Sn on Ge(111), which undergoes a transition from the low temperature (3x3) phase to the room temperature (\sqrt3 x \sqrt3)R30 one. On the basis of scanning tunnelling microscopy experiments, this transition was claimed to be the manifestation of a surface charge density wave (SCDW), i.e. a periodic redistribution of charge, possibly accompanied by a periodic lattice distortion, which determines a change of the surface symmetry. As further experiments with different techniques were being performed, increasing doubts were cast about the SCDW model. We have measured by He scattering the long range order of the 1/3 monolayer phase of Sn on the Ge(111) surface throughout the phase transition. The transition has been found of the order-disorder type with a critical temperature Tc=220 K. The expected 3-State Potts critical exponents are shown to be consistent with the observed power law dependence of the (3x3) order parameter and its correlation length close to Tc, thus excluding a charge density wave driven phase transition.Comment: 6 pages with 4 figures; updated reference

Crystal structure of the yellow 1:2 molecular complex lumiflavin–bisnaphthalene-2,3-diol

In the first molecular complex of the physiologically active neutral form of isoalloxazine studied, lumiflavin–bisnaphthalene-2,3-diol, each flavin is sandwiched between two naphthalenediol molecules with extensive overlap but a moderately large (3·44 Å) spacing, indicating at most weak charge-transfer interaction and in agreement with the yellow colour of the complex, nearly the same as that of the parent lumiflavin

Experiences of health communication within the family: Parent and adolescent perspectives

Background: Adolescence is a critical period for the development of health and well-being and is a pivotal time for transition toward independent health decision making. Family health communication patterns, can influence behaviors and attitudes of adolescents. Health literacy is a pre-requisite for acquiring and comprehending health information. However, minimal research exists examining the connection between health literacy and family communication. Purpose: To examine the risk of limited health literacy and explore the experiences of health communication among families. Methods: 9 Adolescents and 8 parents completed demographic questionnaires, the Newest Vital Sign and private semi-structured qualitative interviews. Glazer’s grounded theory approach was used to identify thematic categories and theoretic cores of the qualitative data. Results: Limited health literacy risk was 12.5% for parents and 22/2% for adolescents. Narrow definitions of health, evaluation methods of information, opportunity and interpretation were the identified themes. Conclusions: Results from our study suggest that within families who are not at risk for limited health literacy, health communication is occurring related to topics of interest to adolescents. These conversations persist despite parental perceptions of these conversations being negative. Further research should investigate parent motivation related to health communication and the role that health literacy may play in motivation toward and ability to engage in family health communication

Digital Image Processing of Electron Micrographs: The PIC System II

The PIC system, an integrated package of Fortran programs and subroutines designed to run on the Digital Equipment Corporation VAX family of computers, has been developed for analysis of electron micrographs with emphasis on the particular requirements for structural analysis of biological macromolecules. The substantially improved VAX version of PIC reported here has been developed from an earlier PDP-11 version which was, in turn, developed from a set of IBM 370 programs called MDPP. PIC now encompasses over 150 commands or processing operations that afford a comprehensive range of image processing operations including image restoration, enhancement, Fourier analysis, correlation averaging, and multivariate statistical analysis including clustering and classification. In particular, we describe our software for correction of imperfect lattices, as well as programs for correlation alignment and averaging of single particle images

Experimental behaviour of a steel structure under natural fire

Current design codes for fire resistance of structures are based on isolated member tests subjected to standard fire conditions. Such tests do not reflect the behaviour of a complete building under either normal temperature or fire conditions. Many aspects of behaviour occur due to the interaction between members and cannot be predicted or observed in tests of isolated elements. Performance of real structures subject to real fires is often much better than that predicted from standard tests due to structural continuity and the provision of alternative load paths.http://www.sciencedirect.com/science/article/B6V37-4KN5C4D-1/1/8f781d0c96159d54029bef7c9ec451b

Experimental behaviour of a steel structure under natural fire

Current design codes for fire resistance of structures are based on isolated member tests subjected to standard fire conditions. Such tests do not reflect the behaviour of a complete building under either normal temperature or fire conditions. Many aspects of behaviour occur due to the interaction between members and cannot be predicted or observed in tests of isolated elements. Performance of real structures subject to real fires is often much better than that predicted from standard tests due to structural continuity and the provision of alternative load paths.http://www.sciencedirect.com/science/article/B6V37-4KN5C4D-1/1/8f781d0c96159d54029bef7c9ec451b