64 research outputs found
Triangular buckling patterns of twisted inextensible strips
When twisting a strip of paper or acetate under high longitudinal tension,
one observes, at some critical load, a buckling of the strip into a regular
triangular pattern. Very similar triangular facets have recently been observed
in solutions to a new set of geometrically-exact equations describing the
equilibrium shape of thin inextensible elastic strips. Here we formulate a
modified boundary-value problem for these equations and construct post-buckling
solutions in good agreement with the observed pattern in twisted strips. We
also study the force-extension and moment-twist behaviour of these strips by
varying the mode number n of triangular facets
Trigonometry of 'complex Hermitian' type homogeneous symmetric spaces
This paper contains a thorough study of the trigonometry of the homogeneous
symmetric spaces in the Cayley-Klein-Dickson family of spaces of 'complex
Hermitian' type and rank-one. The complex Hermitian elliptic CP^N and
hyperbolic CH^N spaces, their analogues with indefinite Hermitian metric and
some non-compact symmetric spaces associated to SL(N+1,R) are the generic
members in this family. The method encapsulates trigonometry for this whole
family of spaces into a single "basic trigonometric group equation", and has
'universality' and '(self)-duality' as its distinctive traits. All previously
known results on the trigonometry of CP^N and CH^N follow as particular cases
of our general equations. The physical Quantum Space of States of any quantum
system belongs, as the complex Hermitian space member, to this parametrised
family; hence its trigonometry appears as a rather particular case of the
equations we obtain.Comment: 46 pages, LaTe
Assessing the efficacy of a modified assertive community-based treatment programme in a developing country
<p>Abstract</p> <p>Background</p> <p>A number of recently published randomized controlled trials conducted in developed countries have reported no advantage for assertive interventions over standard care models. One possible explanation could be that so-called "standard care" has become more comprehensive in recent years, incorporating some of the salient aspects of assertive models in its modus operandi. Our study represents the first randomised controlled trial assessing the effect of a modified assertive treatment service on readmission rates and other measures of outcome in a developing country.</p> <p>Methods</p> <p>High frequency service users were randomized into an intervention (n = 34) and a control (n = 26) group. The control group received standard community care and the active group an assertive intervention based on a modified version of the international model of assertive community treatment. Study visits were conducted at baseline and 12 months with demographic and illness information collected at visit 1 and readmission rates documented at study end. Symptomatology and functioning were measured at both visits using the PANSS, CDSS, ESRS, WHO-QOL and SOFAS.</p> <p>Results</p> <p>At 12 month follow-up subjects receiving the assertive intervention had significantly lower total PANSS (p = 0.02) as well as positive (p < 0.01) and general psychopathology (p = 0.01) subscales' scores. The mean SOFAS score was also significantly higher (p = 0.02) and the mean number of psychiatric admissions significantly lower (p < 0.01) in the intervention group.</p> <p>Conclusions</p> <p>Our results indicate that assertive interventions in a developing setting where standard community mental services are often under resourced can produce significant outcomes. Furthermore, these interventions need not be as expensive and comprehensive as international, first-world models in order to reduce inpatient days, improve psychopathology and overall levels of functioning in patients with severe mental illness.</p
Mixed Climatology, Non-synoptic Phenomena and Downburst Wind Loading of Structures
Modern wind engineering was born in 1961, when Davenport published a paper in which meteorology, micrometeorology, climatology, bluff-body aerodynamics and structural dynamics were embedded within a homogeneous framework of the wind loading of structures called today \u201cDavenport chain\u201d. Idealizing the wind with a synoptic extra-tropical cyclone, this model was so simple and elegant as to become a sort of axiom. Between 1976 and 1977 Gomes and Vickery separated thunderstorm from non-thunderstorm winds, determined their disjoint extreme distributions and derived a mixed model later extended to other Aeolian phenomena; this study, which represents a milestone in mixed climatology, proved the impossibility of labelling a heterogeneous range of events by the generic term \u201cwind\u201d. This paper provides an overview of this matter, with particular regard to the studies conducted at the University of Genova on thunderstorm downbursts
Rubans Ă©lastiques
International audienceElastic strips are critical points, among all arc lenght preserving variations, of the Sadowski functional. This functional measures the bending energy of an infinitely narrow strip. Two new classes of elastic strips are described. It is shown that the binormal curve of an elastic strip of the first class and the tangent curve of an elastic strip of the second class are spherical elastic curves
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