Model-based Crowd Behaviours in Human-solution Space

Realistic crowd simulation has been pursued for decades, but it still necessitates tedious human labour and a lot of trial and error. The majority of currently used crowd modelling is either empirical (model-based) or data-driven (model-free). Model-based methods cannot fit observed data precisely, whereas model-free methods are limited by the availability/quality of data and are uninterpretable. In this paper, we aim at taking advantage of both model-based and data-driven approaches. In order to accomplish this, we propose a new simulation framework built on a physics-based model that is designed to be data-friendly. Both the general prior knowledge about crowds encoded by the physics-based model and the specific real-world crowd data at hand jointly influence the system dynamics. With a multi-granularity physics-based model, the framework combines microscopic and macroscopic motion control. Each simulation step is formulated as an energy optimization problem, where the minimizer is the desired crowd behaviour. In contrast to traditional optimization-based methods which seek the theoretical minimizer, we designed an acceleration-aware data-driven scheme to compute the minimizer from real-world data in order to achieve higher realism by parameterizing both velocity and acceleration. Experiments demonstrate that our method can produce crowd animations that are more realistically behaved in a variety of scales and scenarios when compared to the earlier methods.     

Vortex-Antivortex Lattices in Superconducting Films with Magnetic Pinning Arrays

No Heading We found a rich variety of vortex structures when a thin superconducting film (SC) is covered with a lattice of out-of-plane magnetized magnetic dots (MDs). The vortices are confined to the MD regions, and antivortices nucleate into regular lattices which relax through several second order transitions towards single-dot vortex-antivortex configurations with increasing period of the magnetic array. Creation of vortex-antivortex pairs with increasing MD-magnetization is controlled by a single quantity - the superfluid velocity. We demonstrate that due to the vortex-antivortex pairs and the supercurrents induced by the MDs, the critical current in the sample actually increases if exposed to a homogeneous external magnetic field, contrary to conventional SC behavior. We explain further experimental implications, such as the magnetic field-induced-superconductivity.PACS numbers: 74.78.–w, 74.25.Op, 74.25.Qt, 74.25.Dw.     

The Structure and Manipulation of Vortex States in a Superconducting Square with 2 × 2 Blind Holes

No Heading We consider a mesoscopic square superconductor with 2 × 2 blind holes in the presence of a homogeneous magnetic field. Under suitable conditions a diagonal L = 2 state is realized and the system reduces to double degenerate states with different flux configurations, which can be considered as logic states. We show the possibility of manipulation of these states by circulating currents in a loop near the superconductor.PACS numbers: 74.20.De, 85.25.Hv, 74.78.Na, 74.25.Qt, 74.25.Ha.     

Lasioglossins: Three Novel Antimicrobial Peptides from the Venom of the Eusocial Bee Lasioglossum laticeps (Hymenoptera: Halictidae)

Three novel structurally related pentadecapeptides, named lasioglossins, were isolated from the venom of the eusocial bee Lasioglossum laticeps. Their primary sequences were established as H‐Val‐Asn‐Trp‐Lys‐Lys‐Val‐Leu‐Gly‐Lys‐Ile‐Ile‐Lys‐Val‐Ala‐Lys‐NH₂ (LL‐I), H‐Val‐Asn‐Trp‐Lys‐Lys‐Ile‐Leu‐Gly‐Lys‐Ile‐Ile‐Lys‐Val‐Ala‐Lys‐NH₂ (LL‐II) and H‐Val‐Asn‐Trp‐Lys‐Lys‐Ile‐Leu‐Gly‐Lys‐Ile‐Ile‐Lys‐Val‐Val‐Lys‐NH₂ (LL‐III). These lasioglossins exhibited potent antimicrobial activity against both Gram‐positive and Gram‐negative bacteria, low haemolytic and mast cell degranulation activity, and a potency to kill various cancer cells in vitro. The lasioglossin CD spectra were measured in the presence of trifluoroethanol and sodium dodecyl sulfate solution and indicated a high degree of α‐helical conformation. NMR spectroscopy, which was carried out in trifluoroethanol/water confirmed a curved α‐helical conformation with a concave hydrophobic and convex hydrophilic side. To understand the role of this bend on biological activity, we studied lasioglossin analogues in which the Gly in the centre of the molecule was replaced by other amino acid residues (Ala, Lys, Pro). The importance of the N‐terminal part of the molecule to the antimicrobial activity was revealed through truncation of five residues from both the N and C termini of the LL‐III peptide. C‐terminal deamidation of LL‐III resulted in a drop in antimicrobial activity, but esterification of the C terminus had no effect. Molecular modelling of LL‐III and the observed NOE contacts indicated the possible formation of a bifurcated H‐bond between hydrogen from the Lys15 CONH peptide bond and one H of the C‐terminal CONH₂ to the Ile11 oxygen atom. Such interactions cannot form with C‐terminal esterification.     

The synthesis of bi- and trichromophoric dyes bearing an s-triazinyl ring spacer

An alternative procedure has been described for the syntheses of several bi- and trichromophoric compounds consisting of 1-aminopyrene and 3-aminobenzanthrone chromophoric subsystems connected by an s-triazinyl ring spacer. The synthetic method used, which utilises an autoclave under autogenous pressure, is suitable for the nucleophilic substitution of both chlorine atoms within the triazinyl ring by weakly basic aromatic amines. The structures of the synthesized compounds were confirmed using elemental analysis, ¹H NMR, and mass spectra. UV/vis absorption and fluorescence spectra and fluorescence quantum yields were measured. The dependence of fluorescence intensity and fluorescence quantum yields on solvent polarity was investigated.     

Hybrid Solar Cells from a Blend of Poly(3‐hexylthiophene) and Ligand‐Capped TiO2 Nanorods

Hybrid bulk heterojunction solar cells based on nanocrystalline TiO₂ (nc‐TiO₂) nanorods capped with trioctylphosphine oxide (TOPO) and regioregular poly(3‐hexylthiophene) (P3HT) are processed from solution and characterized in order to relate the device function (optical absorption, charge separation, and transport and photovoltaic properties) to active‐layer properties and device parameters. Annealing the blend films is found to greatly improve the polymer–metal oxide interaction at the nc‐TiO₂/P3HT interface, resulting in a six‐fold increase of the charge separation yield and improved photovoltaic device performance under simulated solar illumination. In addition, the influence of the organic ligand at the nc‐TiO₂ particle surface is found to be crucial for charge separation. Ligand‐exchange procedures applied on the TOPO‐capped nc‐TiO₂ nanorods with an amphiphilic ruthenium‐based dye are found to further improve the charge‐separation yield at the polymer–nanocrystal interface. However, the poor photocurrents generated in the hybrid blend devices, before and after ligand exchange, suggest that transport within or between nanoparticles limits performance. By comparison with other donor–acceptor bulk heterojunction systems, we conclude that charge transport in the nc‐TiO₂:P3HT blend films is limited by the presence of an intrinsic trap distribution mainly associated with the nc‐TiO₂ particles.     

Calcium hydrosilicate as a base for producing thermal insulation products

We have conducted research on the process for producing thermal insulation materials using calcium silicates with the addition of glass fibres. These materials have excellent refractoriness, heat resistance, mechanical strength and dimensional stability and are suitable for refractory coatings, as heat insulators, and as a lagging product.

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Resume Nous avons mené une recherche sur le processus de fabrication de matériaux d’isolation avec des silicates de calcium renforcés de fibres de verre. Ces isolants présentent d’excelllentes résistances à la chaleur et au feu, aussi bien que de bonnes résistance mécanique et stabilité dimensionelle, et se prêtent donc à la confection de revêtements réfractaires, d’isolants thermiques et de calorifuges.