2,340 research outputs found
Motion Planning in Humans and Robots
We present a general framework for generating trajectories and actuator forces that will take a robot system from an initial configuration to a goal configuration in the presence of obstacles observed with noisy sensors. The central idea is to find the motion plan that optimizes a performance criterion dictated by specific task requirements. The approach is motivated by studies of human voluntary manipulation tasks that suggest that human motions can be described as solutions of certain optimization problems
Interaction of chemical patterns in coupled layers
We investigate the interaction between reaction-diffusion systems coupled by diffusion. The photosensitive CDIMA (chorine dioxide–iodine–malonic acid) reaction allows us to study experimentally the mutual influence of two layers of Turing patterns coupled via a diffusive interaction. By illuminating each of the layers with different intensities of homogeneous external light, the chemical conditions in each layer can be shifted, allowing us to study the result of diffusive interaction between Turing patterns with different spatial configurations. Our experiments suggest a complex scenario for the interaction between different patterns, strongly dependent on the spatial characteristics of the interacting patterns. Numerical simulations are also reported in full agreement with experimental observationsThis work has been supported by the DGI (Spain) under Project No. FIS2010-21023 and Xunta de Galicia (Spain) under Project Nos. PGIDIT05PXIC20607PN and INCITE07PXI206131ES and by the NSF (USA). D.G.M. acknowledges a Ramon y Cajal Fellowship from the Ministry of Science and Technology of Spain and a Marie Curie International Reintegration Grant from the EU248346-NMSSBLS, as well as financial support from the CSIC-SPAIN (JAE-DOC
The ACS Virgo Cluster Survey II. Data Reduction Procedures
The ACS Virgo Cluster Survey is a large program to carry out multi-color
imaging of 100 early-type members of the Virgo Cluster using the Advanced
Camera for Surveys (ACS) on the Hubble Space Telescope. Deep F475W and F850LP
images (~ SDSS g and z) are being used to study the central regions of the
program galaxies, their globular cluster systems, and the three-dimensional
structure of Virgo itself. In this paper, we describe in detail the data
reduction procedures used for the survey, including image registration,
drizzling strategies, the computation of weight images, object detection, the
identification of globular cluster candidates, and the measurement of their
photometric and structural parameters.Comment: 33 pages, 8 figures. Accepted for publication in ApJS. Also available
at http://www.physics.rutgers.edu/~pcote/acs/publications.htm
Synthesis, structural characterization and antimicrobial activity of silver(I) complexes with 1-benzyl-1H-tetrazoles
Herein, we report the synthesis and structural characteristics of three tetrazole-containing compounds, 1-benzyl-1H-tetrazole (bntz), 1-benzyl-1H-tetrazol-5-amine (bntza) and 1-(4-methoxybenzyl)-1H-tetrazol-5-amine (mbntza) and the corresponding silver(I) complexes of the general formula [Ag(NO3-O)(L-N4)(2)](n), L = bntz (1), bntza (2) and mbntza (3). Silver(I) complexes 1-3 and 1-benzyl-1H-tetrazoles have been studied in detail by NMR, IR and UV-Vis spectroscopic methods and the structures of 1 and 2 have been determined by single-crystal X-ray diffraction analysis. The results of these analyses revealed a monodentate coordination of the ligands to Ag(I) ion via the N4 tetrazole nitrogen. The antimicrobial potential of silver(I) complexes 1-3 was evaluated against the broad panel of Gram-positive and Gram-negative bacteria and fungi, displaying their remarkable inhibiting activity with MIC (minimal inhibitory concentration) values in the range 2-8 and 0.16-1.25 mu g/mL (3.8-16.3 and 0.31-2.15 mu M), respectively. On the other hand, 1-benzyl-1H-tetrazoles used for the synthesis of the silver(I) complexes were not active against the investigated strains, suggesting that the activity of the complexes originates from the Ag(I) ion exclusively. Moreover, silver(I) complexes 1-3 have good therapeutic potential, which can be deduced from their moderate cytotoxicity on the human fibroblast cell line MRC5, with IC50 values falling in the range 30-60 mu g/mL (57.7-103.4 mu M).Related to published version: [https://imagine.imgge.bg.ac.rs/handle/123456789/1144]This is the peer-reviewed version of the article: Andrejević, T. P., Nikolić, A. M., Glišić, B., Wadepohl, H., Vojnović, S., Zlatović, M., Petković, M., Nikodinović-Runić, J., Opsenica, I. M., & Djuran, M. (2018). Synthesis, structural characterization and antimicrobial activity of silver(I) complexes with 1-benzyl-1H-tetrazoles. Polyhedron, 154, 325–333. [https://doi.org/10.1016/j.poly.2018.08.001
On the Transmission of Colour Image Over Double Generalized Gamma FSO Channel
In this paper performance analysis of colour image Free Space Optics (FSO) transmission over Double Generalized Gamma (DGG) turbulence communication channel is carried out. At the reception side, we have used an average bit error rate (ABER) for reconstructed image performance measure, as the function of FSO link transmission parameters, such as propagation distance, Rytov variance and turbulence shaping and severity parameters (γ1, γ2, m1, m2). Obtained results cover a large number of colour image FSO transmission scenarios, for Gamma-Gamma, Double-Weibull and K turbulence models channels considered as special cases
Long-Lived Coherent Acoustic Phonons in Epitaxially Grown III-V Adiabatic Cavities
We provide evidence of strongly confined coherent acoustic phonons inside
high quality factor phononic cavities that exhibit tailoredphonon potentials.
Using GaAs/AlAs quasiperiodic superlattices, these functional phonon potentials
are realized by adiabatically changing the layer thicknesses along the growth
direction. Room temperature ultrafast vibrational spectroscopy reveals discrete
phonon levels in the range of GHz. Additionally, we confirm
that phononic cavities significantly retard the energy loss rate of the
photoexcited carriers as evidenced by time-resolved photoluminescence
measurements. These results highlight the potential of opto-phononic devices
that can bridge the divide between phononics and optoelectronics by
concurrently engineering electronic and phononic properties.Comment: In this version, we have incorporated a new section addressing the
temporal dynamics of cavity phonons. Additionally, the analysis and
discussion of time-resolved photoluminescence (TRPL) results have been
enhance
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