Search results for "Transmission"
showing 10 items of 2080 documents
Side-lobe suppression in electro-optic pulse generation
2007
A simple method is presented for rejecting undesirable tails and wings, around the main pulses of a periodic train, which is generated by electro-optical, sinusoidal phase modulation. It is shown that, by using a broadband optical carrier, the nonlinear chirp components generated by sinusoidal phase modulation can be filtered out. Thus, nearly apodised picosecond pulsation can be generated.
Gaussian pulse propagation in dispersion-managed systems using chirped fiber gratings with group delay ripples
2005
We study the propagation of Gaussian-shaped pulses in grating-compensated dispersion-managed systems with group delay ripples (GDR). We show that the intersymbol interference caused by the GDR in gratings can be substantially reduced by nonlinear optical loop mirrors and the 40-Gb/s system performance can achieve transoceanic transmission in the presence of amplifier noise and random variations in ripple period of the gratings along the transmission line.
High performance configuration of all-raman N &#x000D7; 40 Gbit/s RZ-DPSK systems over ultrawave<sup>TM</sup> maps
2007
In order to explore the impact of the DPSK format on best system configuration, and to cross-check the simulation tools, transmission experiments involving 16 × 40 Gbit/s WDM channels on a recirculating loop including a symmetric UltrawaveTM fiber dispersion map are performed. In these experiments the RZ-DPSK format is used, and each 100 km span is brought to optical transparency with 75%(25%) of backward (forward) Raman gain. The pre-compensation is experimentally varied, and a significant transmission improvement after 4000 km for the pre-compensation of -350 ps/nm is observed.
Status of the EPIC thin and medium filters on-board XMM-Newton after more than 10 years of operation II: analysis of in-flight data
2013
After more than ten years of operation of the EPIC camera on board the X-ray observatory XMM-Newton we have reviewed the status of its thin and medium filters by performing both analysis of data collected in-flight and laboratory measurements on on-ground back-up filters. We have investigated the status of the EPIC thin and medium filters by performing an analysis of the optical loading in the PN offset maps to gauge variations in the optical and UV transmission of the filters. We both investigated repeated observations of single optically bright targets and performed a statistical analysis of the extent of loading versus visual magnitude at different epochs. We report the results of these …
Suppression of soliton self-frequency shift by up-shifted filtering
2002
We propose an efficient method for suppressing the soliton self-frequency shift in high-speed transmission lines by means of up-shifted filters.
A novel arousal-based individual screening reveals susceptibility and resilience to PTSD-like phenotypes in mice
2021
Translational animal models for studying post-traumatic stress disorder (PTSD) are valuable for elucidating the poorly understood neurobiology of this neuropsychiatric disorder. These models should encompass crucial features, including persistence of PTSD-like phenotypes triggered after exposure to a single traumatic event, trauma susceptibility/resilience and predictive validity. Here we propose a novel arousal-based individual screening (AIS) model that recapitulates all these features. The AIS model was designed by coupling the traumatization (24 h restraint) of C57BL/6 J mice with a novel individual screening. This screening consists of z-normalization of post-trauma changes in startle …
Relations between basal ganglia and hippocampus: Action of substantia nigra and pallidum
1986
Several interrelationships exist between basal ganglia and hippocampus. The ventral striatum appears to be involved in the control of the dopaminergic nigro-striatal pathway. The caudate, in turn, seems to influence the hippocampal theta rhythm and to inhibit hippocampal spikes. In the present work the role played by globus pallidus pars interna and substantia nigra pars compacta on hippocampal bioelectrical activity is studied. Injection of sodium penicillin i.v. produces steady interictal spikes in the hippocampus. Substantia nigra stimulation induces regular theta rhythm and inhibits the spikes. Pallidal stimulation, on the contrary, appears to strongly enhance epileptiform activity, pro…
Biosilicification of loricate choanoflagellate: organic composition of the nanotubular siliceous costal strips of Stephanoeca diplocostata.
2010
SUMMARY Loricate choanoflagellates (unicellular, eukaryotic flagellates; phylum Choanozoa) synthesize a basket-like siliceous lorica reinforced by costal strips (diameter of approximately 100 nm and length of 3 μm). In the present study, the composition of these siliceous costal strips is described, using Stephanoeca diplocostata as a model. Analyses by energy-dispersive X-ray spectroscopy (EDX), coupled with transmission electron microscopy (TEM), indicate that the costal strips comprise inorganic and organic components. The organic, proteinaceous scaffold contained one major polypeptide of mass 14 kDa that reacted with wheat germ agglutinin. Polyclonal antibodies were raised that allowed …
Presynaptic CB1 Receptors Regulate Synaptic Plasticity at Cerebellar Parallel Fiber Synapses
2011
Endocannabinoids are potent regulators of synaptic strength. They are generally thought to modify neurotransmitter release through retrograde activation of presynaptic type 1 cannabinoid receptors (CB1Rs). In the cerebellar cortex, CB1Rs regulate several forms of synaptic plasticity at synapses onto Purkinje cells, including presynaptically expressed short-term plasticity and, somewhat paradoxically, a postsynaptic form of long-term depression (LTD). Here we have generated mice in which CB1Rs were selectively eliminated from cerebellar granule cells, whose axons form parallel fibers. We find that in these mice, endocannabinoid-dependent short-term plasticity is eliminated at parallel fiber…
Physostigmine and Neuromuscular Transmission
1993
Single channel studies carried out in cultured rat myoballs and cultured hippocampal neurons, and ion flux studies performed on Torpedo electrocyte membrane vesicles, showed that physostigmine (Phy), a well-established acetylcholinesterase inhibitor, interacts directly with nicotinic acetylcholine receptors (nAChR). Low concentrations (0.1 microM) of Phy activate the receptor integral channel, whereas higher concentrations blocked the channel in its opened state. In contrast to channel activation by acetylcholine (ACh) and classical cholinergic agonists, however, Phy was capable of activating the nAChR channel even when the ACh binding sites were blocked by competitive antagonists, such as …