274 research outputs found
High-Speed Bi-directional Optical Wireless System in Non-Directed Line-of-Sight Configuration
We propose and experimentally demonstrate the first bi-directional optical wireless link operating in non-direct line-of-sight (Nd-LOS). The system is based on visible light emitting diode (LED) for downlink and infrared LED for uplink. We achieve around 250 Mbit/s for both downstream and upstream transmission, with the ambient light noise of usual indoor illumination level (500 lx), produced by warm-white LED. 100 Mbit/s are guaranteed inside 12 m of a common room scenario, without LOS tracking. An optimized discrete multi-tone modulation gives bit-error-ratios always below of the common forward-error-correction threshold of 1.5 ×10. These results indicate that this scheme has great potential for practical VLC system implementation
Interventi comuni per la difesa dell'ambiente marino quale elemento unificante del parco transfrontaliero
Si riportano alcune esperienze di ricerca ambientale e gestionale propedeutiche alla creazione del Parco Internazionale delle Bocche di Bonifacio tra i ricercatori del Parco Nazionale dell'Arcipelago di La Maddalena e del Parco Regionale della Corsica
Redefining the Genetic Hierarchies Controlling Skeletal Myogenesis: Pax-3 and Myf-5 Act Upstream of MyoD
AbstractWe analyzed Pax-3 (splotch)Myf-5 (targeted with nlacZ), and splotch/Myf-5 homozygous mutant mice to investigate the roles that these genes play in programming skeletal myogenesis. In splotch and Myf-5 homozygous embryos, myogenic progenitor cell perturbations and early muscle defects are distinct. Remarkablysplotch/Myf-5 double homozygotes have a dramatic phenotype not seen in the individual mutants: body muscles are absent. MyoD does not rescue this double mutant phenotype since activation of this gene proves to be dependent on either Pax-3 or Myf-5. ThereforePax-3 and Myf-5 define two distinct myogenic pathways, and MyoD acts genetically downstream of these genes for myogenesis in the body. This genetic hierarchy does not appear to operate for head muscle formation
Electrodynamic friction of a charged particle passing a conducting plate
The classical electromagnetic friction of a charged particle moving with
prescribed constant velocity parallel to a planar imperfectly conducting
surface is reinvestigated. As a concrete example, the Drude model is used to
describe the conductor. The transverse electric and transverse magnetic
contributions have very different character both in the low velocity
(nonrelativistic) and high velocity (ultrarelativistic) regimes. Both numerical
and analytical results are given. Most remarkably, the transverse magnetic
contribution to the friction has a maximum for , and persists
in the limit of vanishing resistivity for sufficiently high velocities. We also
show how Vavilov-\v{C}erenkov radiation can be treated in the same formalism.Comment: 13 pages, 7 figures. This is the extensively revised version accepted
by Physical Review Researc
Skeletal Myogenic Progenitors Originating from Embryonic Dorsal Aorta Coexpress Endothelial and Myogenic Markers and Contribute to Postnatal Muscle Growth and Regeneration
Skeletal muscle in vertebrates is derived from somites, epithelial structures of the paraxial mesoderm, yet many unrelated reports describe the occasional appearance of myogenic cells from tissues of nonsomite origin, suggesting either transdifferentiation or the persistence of a multipotent progenitor. Here, we show that clonable skeletal myogenic cells are present in the embryonic dorsal aorta of mouse embryos. This finding is based on a detailed clonal analysis of different tissue anlagen at various developmental stages. In vitro, these myogenic cells show the same morphology as satellite cells derived from adult skeletal muscle, and express a number of myogenic and endothelial markers. Surprisingly, the latter are also expressed by adult satellite cells. Furthermore, it is possible to clone myogenic cells from limbs of mutant c-Met-/- embryos, which lack appendicular muscles, but have a normal vascular system. Upon transplantation, aorta-derived myogenic cells participate in postnatal muscle growth and regeneration, and fuse with resident satellite cells.
The potential of the vascular system to generate skeletal muscle cells may explain observations of nonsomite skeletal myogenesis and raises the possibility that a subset of satellite cells may derive from the vascular system
3.4 Gbit/s Visible Optical Wireless Transmission Based on RGB LED
In this paper, we experimentally realized a gigabit-class indoor visible light communication system using commercially available RGB White LED and exploiting an optimized DMT modulation. We achieved data rate of 1.5 Gbit/s with single channel and 3.4 Gbit/s by implementing WDM transmission at standard illumination levels. In both experiments, the resulting bit error ratios were below the FEC limit. To the best of our knowledge, these values are the highest ever achieved in VLC systems
Modelization and Characterization of a CMOS Camera as an Optical Real-Time Oscilloscope
Complementary Metal-Oxide Semiconductor (CMOS) camera sensors are embedded in many consumer electronics products: thanks to the Rolling Shutter (RS) readout mode, they can detect a time-varying light intensity, which is the key to realize Optical Camera Communication (OCC). To this aim, we introduce here a model describing the camera as a Real-Time Oscilloscope (RTO) detecting optical signals; by means of this approach, we can now characterize the Complementary Metal-Oxide Semiconductor (CMOS) camera by means of parameters that correspond to common oscilloscope specifications, such as the frequency response, the noise, the Signal to Noise Ratio (SNR), the total harmonic distortion (THD), etc.; all of these are introduced and measured in terms of the camera parameters. This approach provides for the first time a set of quantitative tools that should be used to maximize the OCC transmission performance by allowing the optimal selection of the camera settings
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