Realisations of W3W_3 Symmetry

We perform a systematic investigation of free-scalar realisations of the Za\-mo\-lod\-chi\-kov $W_3$ algebra in which the operator product of two spin-three generators contains a non-zero operator of spin four which has vanishing norm. This generalises earlier work where such an operator was required to be absent. By allowing this spin-four null operator we obtain several realisations of the $W_3$ algebra both in terms of two scalars as well as in terms of an arbitrary number $n$ of free scalars. Our analysis is complete for the case of two-scalar realisations.Comment: 14 pages, LATEX, UG-6/9

Semi-isostatic densification of heat-treated radiata pine

Semi-isostatic densification is a useful method to increase the density and to improve the mechanical properties of fast-grown softwood species like radiata pine. A major disadvantage of this method is the almost complete recovery of the original dimensions when densified wood is exposed to moisture. Heat treatment improves the dimensional stability of wood and might be a useful method to prevent this shape-recovery after densification. However, no or only a limited effect on the shape-recovery was found when densified radiata pine was exposed to moisture

Employment status, job characteristics and work-related health experience of people with a lower limb amputation in the Netherlands

Objectives: To describe the occupational situation of people with lower limb amputations in The Netherlands and to compare the health experience of workings and nonworking amputee patients with a nonimpaired reference population. Design: Cross-sectional study in which patients completed a questionnaire about their job participation. type of job, workplace adjustments to their limb loss, their position in the company, and a general health questionnaire. Setting: Orthopsdic workshops in The Netherlands with a population of lower limb amputees. Patients: Subjects were recruited from orthopedic workshops in the Netherlands. They ranged in age from Is to 60 years (mean, 44.5yr) and had a lower limb amputated at least 2 years (mean, 19.6yr) before this study. Main Outcome measures: A self-report questionnaire, with 1 part concerning patient characteristics and amputation-related factors, and the other concerning job characteristics, vocational handicaps, work adjustments, and working conditions; and a general health questionnaire (RAND-36) to measure health status. Results: Responses were received from 652 of the 687 patients (response: rate, 95%) who were sent the questionnaire. Sixty-foul percent of the respondents were working at the rime of the study (comparable with the employment rate of the general Dutch population), 31 % had work experience but were not presently working, and 5% had no work experience. After their amputations, people shifted to less physically demanding work. The mean delay between the amputation and the return to work was 2.3 years. Many people wished their work was better adjusted to the limitations presented by their disability and they mentioned having problems concerning possibilities fur promotion. Seventy-eight percent of those who stopped working within 2 years after the amputation said that amputation-related factors played a role in their decision. Thirty-four percent said that they might have worked longer if certain adjustments had been made. The health experience of people who were no longer working was significantly worse than that of the working people with amputations. Conclusions: Although amputee patients had a relatively good rate of job participation, they reported problems concerning the long delay between amputation and return to work, problems in finding suitable jobs, fewer possibilities for promotion, and problems in obtaining needed workplace modifications. People who had to stop working because of the amputation showed a worse health experience than working people

More on general pp-brane solutions

Recently it was found that the complete integration of the Einstein-dilaton-antisymmetric form equations depending on one variable and describing static singly charged $p$-branes leads to two and only two classes of solutions: the standard asymptotically flat black $p$-brane and the asymptotically non-flat $p$-brane approaching the linear dilaton background at spatial infinity. Here we analyze this issue in more details and generalize the corresponding uniqueness argument to the case of partially delocalized branes. We also consider the special case of codimension one and find, in addition to the standard domain wall, the black wall solution. Explicit relations between our solutions and some recently found $p$-brane solutions ``with extra parameters'' are presented.Comment: 29 pages, 2 figure

Mirror effect induced by the dilaton field on the Hawking radiation

We discuss the string creation in the near-extremal NS1 black string solution. The string creation is described by an effective field equation derived from a fundamental string action coupled to the dilaton field in a conformally invariant manner. In the non-critical string model the dilaton field causes a timelike mirror surface outside the horizon when the size of the black string is comparable to the Planck scale. Since the fundamental strings are reflected by the mirror surface, the negative energy flux does not propagate across the surface. This means that the evaporation stops just before the naked singularity of the extremal black string appears even though the surface gravity is non-zero in the extremal limit.Comment: 15 page

Executive functioning in adult ADHD: a meta-analytic review

. CONCLUSIONS: Neuropsychological difficulties in adult ADHD may not be confined to executive functioning. The field is in urgent need of better-designed executive functioning tests, methodological improvements, and direct comparisons with multiple clinical groups to answer questions of specificit