1,188 research outputs found
Multigrid solver for axisymmetrical 2D fluid equations
We have developed an efficient algorithm for steady axisymmetrical 2D fluid
equations. The algorithm employs multigrid method as well as standard implicit
discretization schemes for systems of partial differential equations. Linearity
of the multigrid method with respect to the number of grid points allowed us to
use grid, where we could achieve solutions in several minutes.
Time limitations due to nonlinearity of the system are partially avoided by
using multi level grids(the initial solution on grid was
extrapolated steady solution from grid which allowed using
"long" integration time steps). The fluid solver may be used as the basis for
hybrid codes for DC discharges.Comment: preliminary version; presented at 28 ICPIG, July 15-20, 2007, Prague,
Czech Republi
Multinationals, innovation and institutional context: IPR protection and distance effects
We characterize the knowledge production process whereby the inventive capabilities of the firm generate innovation output in highly inventive multinational enterprises (MNEs). We explore the sensitivity of this relationship to the strength of intellectual property rights (IPR) protection across the MNEs R&D subsidiaries. We argue that MNE innovative performance will be enhanced when the firm’s R&D activities are based in locations where IPR protection is stronger. Moreover, when considering the internal geography of the MNEs R&D activities, innovation performance depends on the distance between the home- and host-country IPR regime. Thus, innovation performance is worse, as the difference between home and host IPR regimes increases. Finally, we explore asymmetries in this relationship, in particular that the deterioration is more marked when MNEs locate their R&D activities in host economies with IPR protection significantly less strict than in their home country. We test these ideas using a unique new dataset about the most innovative MNEs in the world, an unbalanced panel of around 900 MNEs observed for the period 2004 to 2013 and find strong support for all our hypotheses
Grid-Obstacle Representations with Connections to Staircase Guarding
In this paper, we study grid-obstacle representations of graphs where we
assign grid-points to vertices and define obstacles such that an edge exists if
and only if an -monotone grid path connects the two endpoints without
hitting an obstacle or another vertex. It was previously argued that all planar
graphs have a grid-obstacle representation in 2D, and all graphs have a
grid-obstacle representation in 3D. In this paper, we show that such
constructions are possible with significantly smaller grid-size than previously
achieved. Then we study the variant where vertices are not blocking, and show
that then grid-obstacle representations exist for bipartite graphs. The latter
has applications in so-called staircase guarding of orthogonal polygons; using
our grid-obstacle representations, we show that staircase guarding is
\textsc{NP}-hard in 2D.Comment: To appear in the proceedings of the 25th International Symposium on
Graph Drawing and Network Visualization (GD 2017
Photoresponse from noble metal nanoparticles-multi walled carbon nanotube composites
In this Letter, we investigated the photo-response of multi wall carbon nanotube-based composites
obtained from in situ thermal evaporation of noble metals (Au, Ag, and Cu) on the nanotube films. The
metal deposition process produced discrete nanoparticles on the nanotube outer walls. The
nanoparticle-carbon nanotube films were characterized by photo-electrochemical measurements in a
standard three electrode cell. The photocurrent from the decorated carbon nanotubes remarkably
increased with respect to that of bare multiwall tubes. With the aid of first-principle calculations, these
results are discussed in terms of metal nanoparticle–nanotube interactions and electronic charge transfer
at the interface.VC 2012 American Institute of Physics
Participatory design of a thematic questionnaire in the field of victimization studies
The paper introduces the results of a two-step process that led to the design of a new questionnaire in the field of victimization studies. A desk-based review of national Crime and Victimization Surveys from five EU countries was performed and resulted in identifying opportunities to improve the consistency among these surveys as well as the need to include more independent variables in order to measure fear of crime and its correlation with sociological variables. Then 12 experts in survey-based measures of crime-related issues were involved in a Delphi panel with the objective of enhancing a participatory design of a new questionnaire addressing individual and space-based determinants of the perception of insecurity, which has been poorly explored to date
On the construction of model Hamiltonians for adiabatic quantum computation and its application to finding low energy conformations of lattice protein models
In this report, we explore the use of a quantum optimization algorithm for
obtaining low energy conformations of protein models. We discuss mappings
between protein models and optimization variables, which are in turn mapped to
a system of coupled quantum bits. General strategies are given for constructing
Hamiltonians to be used to solve optimization problems of
physical/chemical/biological interest via quantum computation by adiabatic
evolution. As an example, we implement the Hamiltonian corresponding to the
Hydrophobic-Polar (HP) model for protein folding. Furthermore, we present an
approach to reduce the resulting Hamiltonian to two-body terms gearing towards
an experimental realization.Comment: 35 pages, 8 figure
Integrated management strategies of Meloidogyne incognita and Pseudopyrenochaeta lycopersici on tomato using a Bacillus firmus-based product and two synthetic nematicides in two consecutive crop cycles in greenhouse
vandetanib improves anti tumor effects of l19mtnfα in xenograft models of esophageal cancer
Purpose: Targeting the tumor vasculature by vascular disrupting agents (VDAs) has shown therapeutic activity in mouse models. In most cases, however, VDA efficacy is substantially compromised by the inability of these drugs to completely kill tumor cells located at the periphery of the tumor mass. In this study, we investigated anti-tumor effects of L19mTNFα, a fusion protein composed of L19 (scFv), specific for the angiogenesis-associated ED-B containing fibronectin isoform, and murine TNFα, in xenograft models of esophageal cancer. Experimental design: We evaluated ED-B expression in esophageal cancer samples. Subsequently, we generated subcutaneous xenografts from primary tumors, treated them with the L19mTNFα scFv, and determined effects on tumor vasculature, viability and proliferation, and VEGF expression and infiltration by hematopoietic cells. To overcome tumor resistance, L19mTNFα scFv was combined with vandetanib, a tyrosine kinase inhibitor of VEGF receptor, epidermal growth factor receptor, and RET signaling. Results: ED-B was broadly expressed by esophageal cancer cell lines, as well as xenografts and primary surgical samples of esophageal cancer. Administration of L19mTNFα acutely damaged tumor vasculature and increased necrosis, indicating a VDA-like activity of this immunoconjugate. This event was followed, however, by rapid tumor growth recovery associated with increased expression of VEGF and recruitment of CD11b+Gr1+ myeloid cells into tumors. Combination of L19mTNFα with vandetanib severely impaired vascular functions in tumors, leading to a reduction of cell proliferation and increased necrosis, without apparent signs of toxicity. Conclusion: These findings indicate that a combination of vascular damaging agents with anti-angiogenic drugs could represent a promising therapeutic strategy for esophageal cancer. Clin Cancer Res; 17(3); 447–58. ©2010 AACR
New Selective Processing Technique for Solar Cells
Abstract A new selective processing technique based on a confined dynamic liquid drop\meniscus is presented. This approach is based on localized wet treatment of silicon wafers using confined and dynamic liquid drop that while in contact with the wafer forms a dynamic liquid meniscus. Such new technique allows to touch in specific defined positions the silicon wafer (front and/or back) in order to perform any kind of wet processing without the need of protective photo-resist. The new selective processing technique allows the metallizations (front and back) of mono and multi crystalline silicon solar cells. The front grid contacts are obtained by locally etching the silicon nitride, forming in a thin layer of meso-porous silicon and totally filling the meso-porous layer by pulse reverse plating a Nickel film. Copper and Tin are then electroplated using the same selective processing. This technology provides an effective solution to avoid silver pastes for front contact grid, as it guarantees low specific contact resistivity (550 μΩcm 2 on a 75 Ω/□ n-type doped emitter) and good adhesion to the silicon substrate (i.e. greater than 550 g/mm). The Al back side of the solar cell are also treated by the new selective process. Tin is directly deposited on Aluminum back contact showing adhesion higher than silver on silicon (i.e. > 1N/mm)
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