Florence

In 1284 the Florence Commune started building the last set of walls that were to surround the city until the second half of the 19th century. In response to the strong demographic and economic expansion of the 13th century, the new walls would have to contain a space commensurate with the present and future grandeur of the Commune.¹ When completed in 1333, the walls circled the city for 8.5 kilometres and contained 73 towers, 15 doors and an area five times that included in the previous walls.     

Ribosome display of mammalian receptor domains

Many mammalian receptor domains, among them a large number of potential therapeutic target proteins, are highly aggregation-prone upon heterologous expression in bacteria. This severely limits functional studies of such receptor domains and also their engineering towards improved properties. One of these proteins is the Nogoreceptor, which plays a central role in mediating the inhibition of axon growth and functional recovery after injury of the adult mammalian central nervous system. We show here that the ligand binding domain of the Nogoreceptor folds to an active conformation in ternary ribosomal complexes, as formed in ribosome display. In these complexes the receptor is still connected, via a C-terminal tether, to the peptidyl tRNA in the ribosome and the mRNA also stays connected. The ribosome prevents aggregation of the protein, which aggregates as soon as the release from the ribosome is triggered. In contrast, no active receptor was observed in phage display, where aggregation appears to prevent incorporation of the protein into the phage coat. This strategy sets the stage for rapidly studying defined mutations of such aggregation-prone receptors in vitro and to improve their properties by in vitro evolution using the ribosome display technology.     

Statics Aware Grid Shells

We introduce a framework for the generation of polygonal gridshell architectural structures, whose topology is designed in order to excel in static performances. We start from the analysis of stress on the input surface and we use the resulting tensor field to induce an anisotropic nonEuclidean metric over it. This metric is derived by studying the relation between the stress tensor over a continuous shell and the optimal shape of polygons in a corresponding gridshell. Polygonal meshes with uniform density and isotropic cells under this metric exhibit variable density and anisotropy in Euclidean space, thus achieving a better distribution of the strain energy over their elements. Meshes are further optimized taking into account symmetry and regularity of cells to improve aesthetics. We experiment with quad meshes and hexdominant meshes, demonstrating that our gridshells achieve better static performances than stateoftheart gridshells.     

Understanding dengue fever dynamics: a study of seasonality in vector-borne disease models

Dengue fever dynamics show seasonality, with the disease transmission being higher during the warmer seasons. In this paper, we analyse seasonally forced epidemic models with and without vector dynamics. We assume small seasonal effects and obtain approximations for the real response of each state variable and also for the corresponding amplitude and phase via decomposition of the sinusoidal forcing into imaginary exponential functions. The analysis begins with the simplest susceptible-infected-susceptible (SIS) model, followed by the simplest model with vector dynamics, susceptible-infected-susceptible for hosts and uninfected-vector (SISUV). Finally, we compare the more complex susceptible-infected-recovered (SIR) and susceptible-infected-recovered for hosts and uninfected-vector (SIRUV) models and conclude that the models give basically the same information when we replace, in the SIR model, the human infectivity by a function of both human and mosquito infectivities.     

Review of Protecting Children from Domestic Violence: Strategies for Community Intervention.

Reviews the book Protecting children from domestic violence: Strategies for community intervention, edited by Peter J. Jaffe, Linda L. Baker, and Alison J. Cunningham (see record 2005-04430-000). The book emerged from the International Conference on Children Exposed to Domestic Violence that was held in London, Ontario in 2001. It begins with an excellent chapter by Jeffrey Edleson synthesizing the literature on the impact of exposure to domestic violence on children. Edleson's chapter is followed by two papers examining emerging assessments and treatment programs. The second section of the book addresses current thinking about individual and group intervention approaches. The third section of the book examines broader system level responses, including public awareness and school-based campaigns, as well as responses by the courts and police. This is a well-organized collection of papers that provides a good overview of the state of knowledge and innovative practice in an emerging field of practice. Protecting Children from Domestic Violence provides practitioners, policy makers, and researchers with an excellent overview of current knowledge and practices in working with children exposed to domestic violence. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Characterization of Micro-Powders for the Fabrication of Compression Molded THz Lenses

We investigate different micro-powders that can be used as base materials for THz lenses fabricated by compression molding. For this application materials with a very weak THz absorbance and low dispersion are required. By measuring the THz absorption coefficient and refractive index of pellets pressed from the different micro-powders, we identify several materials that are well suited for the fabrication of compression molded THz lenses (CMLs). In addition, a considerable range of the refractive index is covered by the samples, which will allow for the fabrication of CMLs with different focal lengths for one and the same lens design.     

Nanohybrid Materials with Tunable Birefringence via Cation Exchange in Polymer Films

In this work, a nanohybrid material based on a freestanding polymeric liquid crystal network capable of postmodification via cation exchange to tune birefringence is proposed. The smectic liquid crystal films can be infiltrated with a variety of cations, thereby changing the refractive indices (n_e and n_o) and the effective birefringence (Δn) of the nanohybrid material, with reversible cation infiltration occurring within minutes. Birefringence could be tuned between values of 0.06 and 0.19, depending on the cation infiltrated into the network. Upon infiltration, a decrease in the smectic layer spacing is found with layer contraction independent of the induced change in birefringence. Potential applications are in the field of specialty optical devices, such as flexible, retunable reflective filters.