The inception of Symplectic Geometry: the works of Lagrange and Poisson during the years 1808-1810

The concept of a symplectic structure first appeared in the works of Lagrange on the so-called "method of variation of the constants". These works are presented, together with those of Poisson, who first defined the composition law called today the "Poisson bracket". The method of variation of the constants is presented using today's mathematical concepts and notations.Comment: Presented at the meeting "Poisson 2008" in Lausanne, July 2008. Published in Letters in Mathematical Physics. 22 page

Recognising and understanding cryopyrin-associated periodic syndrome in adults

Cryopyrin-associated periodic syndrome (CAPS) is a group of rare hereditary autoinflammatory diseases characterised by recurrent flares of mild to severe systemic inflammation and fever. CAPS is the umbrella term for a spectrum of individual conditions, namely familial cold autoinflammatory syndrome (FCAS), Muckle-Wells syndrome (MWS) and neonatal-onset multisystem inflammatory disease (NOMID), also known as chronic infantile neurologic, cutaneous and articular (CINCA) syndrome. The flare symptoms include fever, fatigue, rashes, headaches, arthralgia and myalgia that can last for a few hours or for several days. These symptoms are debilitating, contributing to poor quality of life for patients if left untreated. Serious life-changing complications such as hearing loss, blindness and AA amyloidosis resulting in kidney failure can occur. Until recently, treatment of the disease was symptomatic using non-steroidal anti-inflammatory and immunosuppressant drugs with limited success. In contrast, biological treatments targeting interleukin 1 (IL-1) have proved remarkably effective, often associated with complete and sustained disease remission, vastly improved quality of life and avoidance of serious long-term complications

An Obstruction to Quantization of the Sphere

In the standard example of strict deformation quantization of the symplectic sphere $S^2$, the set of allowed values of the quantization parameter $\hbar$ is not connected; indeed, it is almost discrete. Li recently constructed a class of examples (including $S^2$) in which $\hbar$ can take any value in an interval, but these examples are badly behaved. Here, I identify a natural additional axiom for strict deformation quantization and prove that it implies that the parameter set for quantizing $S^2$ is never connected.Comment: 23 page. v2: changed sign conventio

Four dimensional Lie symmetry algebras and fourth order ordinary differential equations

Realizations of four dimensional Lie algebras as vector fields in the plane are explicitly constructed. Fourth order ordinary differential equations which admit such Lie symmetry algebras are derived. The route to their integration is described.Comment: 12 page

Fabric formed concrete: Physical modelling for assessment of digital form finding methods

Fabric formwork is a novel concrete construction method which replaces conventional prismatic moulds with lightweight, high strength sheets of fabric. The geometry of fabric formed structures is therefore dictated by the behaviour of fabric under hydrostatic loading. While there are numerous examples of digital and physical modelling of this problem, there have only been limited efforts to link the two through measurement. In this investigation, a number of small scale fabric formed beams were manufactured using both ‘free hanging’ and ‘keel mould’ methods, and the resulting forms were accurately measured with a digital 3D scanner. Computational form finding tools were also developed, enabling a comparison to be made between the predicted and build geometries. This allowed assessment of both the accuracy of the construction methods and the limitations of the form finding techniques used. The data collected provides a useful assessment of existing form finding techniques and will be used as a reference data set as these are developed further

A design methodology to reduce the embodied carbon of concrete buildings using thin-shell floors

This paper explores the potential of thin concrete shells as a low-carbon alternative to floor slabs and beams, which typically make up the majority of structural material in multi-storey buildings. A simple and practical system is proposed, featuring pre-cast textile reinforced concrete shells with a network of prestressed steel tension ties. A non-structural ll is included to provide a level top surface. Building on previous experimental and theoretical work, a complete design methodology is presented. This is then used to explore the structural behaviour of the proposed system, refi ne its design, and evaluate potential carbon savings. Compared to at slabs of equivalent structural performance, signi cant embodied carbon reductions (53-58%) are demonstrated across spans of 6-18m. Self-weight reductions of 43-53% are also achieved, which would save additional material in columns and foundations. The simplicity of the proposed structure, and conservatism of the design methodology, indicate that further savings could be made with future refinements. These results show that considerable embodied carbon reductions are possible through innovative structural design, and that thin-shell floors are a practical means of achieving this

Traffic noise alters individual social connectivity, but not space-use, of Red-backed Fairywrens

The prevalence of human-generated noise is posing novel challenges to birds, by changing how they communicate or causing them to disperse away from the source of noise. We sought to understand how noise affected space-use and social connectivity in a small passerine bird, the Red-backed Fairywren (Malurus melanocephalus). As the displaced birds would likely be forced to occupy a smaller area that may already have resident individuals, we predicted that noise-affected birds would show increased social connectivity that may include new individuals. To test this, we introduced an experimental point-source of traffic noise to groups of fairywrens in an otherwise quiet habitat and compared the change in social connectivity of birds in groups exposed to noise to the changes in social connectivity in neighbouring groups unaffected by noise. Contrary to our prediction, noise-affected birds had reduced social connectivity during experimental noise treatments, as measured by weighted-degree, which was driven by a reduction of interactions with birds of neighbouring groups outside the noise zone. Additionally, we did not discern a change in space-use in response to our noise treatment. Therefore, we suggest that noise reduces the efficacy of signal transmission and detection in this species, resulting in the reduction of social connectivity between groups of this otherwise highly social songbird

Thin-shell textile-reinforced concrete floors for sustainable buildings

Steel-reinforced concrete, cast in flat prismatic forms, dominates multi-storey building construction around the world. Despite the fluidity of the material, opportunities to create efficient geometries through manipulation of form are habitually overlooked, resulting in inefficient cracked sections, high steel requirements and large carbon footprints. This project brings together modern developments in computational design, materials and construction to propose a novel thin-shell concrete flooring system for multi-storey buildings, creating a low embodied energy and lightweight alternative to traditional reinforced concrete flat slabs. In this investigation, the performance of various shell geometries are compared using finite element analysis. A functional design is produced and found to offer reductions of 62% in embodied energy and 64% in weight compared to an equivalent flat slab

Alterations in vasodilator-stimulated phosphoprotein (VASP) phosphorylation: associations with asthmatic phenotype, airway inflammation and β\u3csub\u3e2\u3c/sub\u3e-agonist use

Background Vasodilator-stimulated phosphoprotein (VASP) mediates focal adhesion, actin filament binding and polymerization in a variety of cells, thereby inhibiting cell movement. Phosphorylation of VASP via cAMP and cGMP dependent protein kinases releases this brake on cell motility. Thus, phosphorylation of VASP may be necessary for epithelial cell repair of damage from allergen-induced inflammation. Two hypotheses were examined: (1) injury from segmental allergen challenge increases VASP phosphorylation in airway epithelium in asthmatic but not nonasthmatic normal subjects, (2) regular in vivo β2-agonist use increases VASP phosphorylation in asthmatic epithelium, altering cell adhesion. Methods Bronchial epithelium was obtained from asthmatic and non-asthmatic normal subjects before and after segmental allergen challenge, and after regularly inhaled albuterol, in three separate protocols. VASP phosphorylation was examined in Western blots of epithelial samples. DNA was obtained for β2-adrenergic receptor haplotype determination. Results Although VASP phosphorylation increased, it was not significantly greater after allergen challenge in asthmatics or normals. However, VASP phosphorylation in epithelium of nonasthmatic normal subjects was double that observed in asthmatic subjects, both at baseline and after challenge. Regularly inhaled albuterol significantly increased VASP phosphorylation in asthmatic subjects in both unchallenged and antigen challenged lung segment epithelium. There was also a significant increase in epithelial cells in the bronchoalveolar lavage of the unchallenged lung segment after regular inhalation of albuterol but not of placebo. The haplotypes of the β2-adrenergic receptor did not appear to associate with increased or decreased phosphorylation of VASP. Conclusion Decreased VASP phosphorylation was observed in epithelial cells of asthmatics compared to nonasthmatic normals, despite response to β-agonist. The decreased phosphorylation does not appear to be associated with a particular β2-adrenergic receptor haplotype. The observed decrease in VASP phosphorylation suggests greater inhibition of actin reorganization which is necessary for altering attachment and migration required during epithelial repair

Kinematics of Metal-Poor Stars in the Galaxy. III. Formation of the Stellar Halo and Thick Disk as Revealed from a Large Sample of Non-Kinematically Selected Stars

(Abbreviated) We present a detailed analysis of the space motions of 1203 solar-neighborhood stars with metal abundances [Fe/H] <= -0.6, on the basis of a recently revised and supplemented catalog of metal-poor stars selected without kinematic bias (Beers et al. 2000). This sample, having available proper motions, radial velocities, and distance estimates for stars with a wide range of metal abundances, is by far the largest such catalog to be assembled to date. Unlike essentially all previous kinematically selected catalogs, the metal-poor stars in our sample exhibit a diverse distribution of orbital eccentricities, e, with no apparent correlation between [Fe/H] and e. This demonstrates, clearly and convincingly, that the evidence offered by Eggen, Lynden-Bell, and Sandage (1962) for a rapid collapse of the Galaxy, an apparent correlation between the orbital eccentricity of halo stars with metallicity, is basically the result of their proper-motion selection bias. However, even in our non-kinematically selected sample, we have identified a small concentration of high-e stars at [Fe/H] = -1.7, which may originate, in part, from infalling gas during the early formation of the Galaxy. The implications of our results for the formation of the Galaxy are also discussed, in particular in the context of the currently favored CDM theory of hierarchical galaxy formation.Comment: 51 pages, including 17 figures, to appear in AJ (June 2000), full paper with all figures embedded available at http://pluto.mtk.nao.ac.jp/people/chiba/preprint/halo5