19,453 research outputs found
Synaptic interactions between perifornical lateral hypothalamic area, locus coeruleus nucleus and the oral pontine reticular nucleus are implicated in the stage succession during sleep-wakefulness cycle
This Document is Protected by copyright and was first published by Frontiers. All rights reserved. it is reproduced with permissionThe perifornical area in the posterior lateral hypothalamus (PeFLH) has been implicated in several physiological functions including the sleep-wakefulness regulation. The PeFLH area contains several cell types including those expressing orexins (Orx; also known as hypocretins), mainly located in the PeF nucleus. The aim of the present study was to elucidate the synaptic interactions between Orx neurons located in the PeFLH area and different brainstem neurons involved in the generation of wakefulness and sleep stages such as the locus coeruleus (LC) nucleus (contributing to wakefulness) and the oral pontine reticular nucleus (PnO) nucleus (contributing to REM sleep). Anatomical data demonstrated the existence of a neuronal network involving the PeFLH area, LC, and the PnO nuclei that would control the sleep-wake cycle. Electrophysiological experiments indicated that PeFLH area had an excitatory effect on LC neurons. PeFLH stimulation increased the firing rate of LC neurons and induced an activation of the EEG. The excitatory effect evoked by PeFLH stimulation in LC neurons was blocked by the injection of the Orx-1 receptor antagonist SB-334867 into the LC. Similar electrical stimulation of the PeFLH area evoked an inhibition of PnO neurons by activation of GABAergic receptors because the effect was blocked by bicuculline application into the PnO. Our data also revealed that the LC and PnO nuclei exerted a feedback control on neuronal activity of PeFLH area. Electrical stimulation of LC facilitated firing activity of PeFLH neurons by activation of catecholaminergic receptors whereas PnO stimulation inhibited PeFLH neurons by activation of GABAergic receptors. In conclusion, Orx neurons of the PeFLH area seem to be an important organizer of the wakefulness and sleep stages in order to maintain a normal succession of stages during the sleep-wakefulness cycl
Transcranial Electric Stimulation Entrains Cortical Neuronal Populations in Rats
Low intensity electric fields have been suggested to affect the ongoing neuronal activity in vitro and in human studies. However, the physiological mechanism of how weak electrical fields affect and interact with intact brain activity is not well understood. We performed in vivo extracellular and intracellular recordings from the neocortex and hippocampus of anesthetized rats and extracellular recordings in behaving rats. Electric fields were generated by sinusoid patterns at slow frequency (0.8, 1.25 or 1.7 Hz) via electrodes placed on the surface of the skull or the dura. Transcranial electric stimulation (TES) reliably entrained neurons in widespread cortical areas, including the hippocampus. The percentage of TES phase-locked neurons increased with stimulus intensity and depended on the behavioral state of the animal. TES-induced voltage gradient, as low as 1 mV/mm at the recording sites, was sufficient to phase-bias neuronal spiking. Intracellular recordings showed that both spiking and subthreshold activity were under the combined influence of TES forced fields and network activity. We suggest that TES in chronic preparations may be used for experimental and therapeutic control of brain activity
AUSTRIA 2020: The impact of medium-term global trends on the Austrian economy
This study quantifies possible impacts of medium-term structural changes in the global economy on the Austrian economy. Emphasis is placed on the effects of continued medium term growth in emerging markets, especially in Asia and Latin America, on the structure of the Austrian economy. The issues here include the identification of price effects (due to increased demand for raw materials) that can be expected, as well as how these may impact the commodity composition of both exports and imports. Underlying global trends also involve both investment patterns and total factor productivity trends at a more regional level, also impacting on the Austrian economy. Finally, these structural changes at the global level also lead to changes in household incomes and the cost of living in Austria, impacting on patterns of inequality in Austria at the household level.CGE models, GTAP applications, household inequality
An assessment of the Instrument Pointing Subsystems (IPS) requirements for spacelab missions
Instrument Pointing Subsystem requirements for Spacelab missions in solar physics, stellar astronomy, and earth observation are analyzed and design guidelines for fine pointing instrument platforms are presented. The requirements for the platforms are time-phased based on NASA projections of flight mission models and payload scheduling. The experiments used for these projections are to be viewed as representative payloads. Other experiments or experiment groupings within any one discipline may be accommodated by an Instrument Pointing Subsystem that meets these requirements
Reconfigurable nanoelectronics using graphene based spintronic logic gates
This paper presents a novel design concept for spintronic nanoelectronics
that emphasizes a seamless integration of spin-based memory and logic circuits.
The building blocks are magneto-logic gates based on a hybrid
graphene/ferromagnet material system. We use network search engines as a
technology demonstration vehicle and present a spin-based circuit design with
smaller area, faster speed, and lower energy consumption than the
state-of-the-art CMOS counterparts. This design can also be applied in
applications such as data compression, coding and image recognition. In the
proposed scheme, over 100 spin-based logic operations are carried out before
any need for a spin-charge conversion. Consequently, supporting CMOS
electronics requires little power consumption. The spintronic-CMOS integrated
system can be implemented on a single 3-D chip. These nonvolatile logic
circuits hold potential for a paradigm shift in computing applications.Comment: 14 pages (single column), 6 figure
Hard X-ray imaging facility for space shuttle: A scientific and conceptual engineering study
A shuttle-accommodated instrument for imaging hard X-rays in the study of nonthermal particles and high temperature particles in various solar and cosmic phenomena was defined and its feasibility demonstrated. The imaging system configuration is described as well as the electronics, aspect systems, mechanical and thermal properties and the ground support equipment
Measurement of Transverse Polarization of Electrons Emitted in Free Neutron Decay
The final analysis of the experiment determining both components of the
transverse polarization of electrons (, )
emitted in the -decay of polarized, free neutrons is presented. The
T-odd, P-odd correlation coefficient quantifying ,
perpendicular to the neutron polarization and electron momentum, was found to
be 0.0040.005. This value is consistent with time reversal
invariance, and significantly improves both earlier result and limits on the
relative strength of imaginary scalar couplings in the weak interaction. The
value obtained for the correlation coefficient associated with
, 0.0670.004, agrees with the Standard Model
expectation, providing an important sensitivity test of the experimental setup.
The present result sets constraints on the imaginary part of scalar and tensor
couplings in weak interaction. Implications for parameters of the leptoquark
exchange model and minimal supersymmetric model (MSSM) with R-parity violation
are discussed
Specific instrumentation and diagnostics for high-intensity hadron beams
An overview of various typical instruments used for high-intensity hadron
beams is given. In addition, a few important diagnostic methods are discussed
which are quite special for these kinds of beams.Comment: 58 pages, contribution to the CAS - CERN Accelerator School: Course
on High Power Hadron Machines; 24 May - 2 Jun 2011, Bilbao, Spai
- …