WorldWideScience

Sample records for non-selective refocusing radio

  1. Design of non-selective refocusing pulses with phase-free rotation axis by gradient ascent pulse engineering algorithm in parallel transmission at 7T.

    Science.gov (United States)

    Massire, Aurélien; Cloos, Martijn A; Vignaud, Alexandre; Le Bihan, Denis; Amadon, Alexis; Boulant, Nicolas

    2013-05-01

    At ultra-high magnetic field (≥ 7T), B1 and ΔB0 non-uniformities cause undesired inhomogeneities in image signal and contrast. Tailored radiofrequency pulses exploiting parallel transmission have been shown to mitigate these phenomena. However, the design of large flip angle excitations, a prerequisite for many clinical applications, remains challenging due the non-linearity of the Bloch equation. In this work, we explore the potential of gradient ascent pulse engineering to design non-selective spin-echo refocusing pulses that simultaneously mitigate severe B1 and ΔB0 non-uniformities. The originality of the method lays in the optimization of the rotation matrices themselves as opposed to magnetization states. Consequently, the commonly used linear class of large tip angle approximation can be eliminated from the optimization procedure. This approach, combined with optimal control, provides additional degrees of freedom by relaxing the phase constraint on the rotation axis, and allows the derivative of the performance criterion to be found analytically. The method was experimentally validated on an 8-channel transmit array at 7T, using a water phantom with B1 and ΔB0 inhomogeneities similar to those encountered in the human brain. For the first time in MRI, the rotation matrix itself on every voxel was measured by using Quantum Process Tomography. The results are complemented with a series of spin-echo measurements comparing the proposed method against commonly used alternatives. Both experiments confirm very good performance, while simultaneously maintaining a low energy deposition and pulse duration compared to well-known adiabatic solutions. Copyright © 2013 Elsevier Inc. All rights reserved.

  2. Enhanced Quantum Communication via Optical Refocusing

    CERN Document Server

    Lupo, Cosmo; Pirandola, Stefano; Mancini, Stefano; Lloyd, Seth

    2011-01-01

    We consider the problem of quantum communication mediated by an optical refocusing system, which is schematized as a thin lens with a finite pupil. This model captures the basic features of all those situations in which a signal is either refocused by a repeater for long distance communication, or it is focused on a detector prior to the information decoding process. Introducing a general method for linear optical systems, we compute the communication capacity of the refocusing apparatus. Although the finite extension of the pupil may cause loss of information, we show that the presence of the refocusing system can substantially enhance the rate of reliable communication with respect to the free-space propagation.

  3. Enhanced quantum communication via optical refocusing

    Energy Technology Data Exchange (ETDEWEB)

    Lupo, Cosmo [School of Science and Technology, University of Camerino, I-62032 Camerino (Italy); Giovannetti, Vittorio [National Enterprise for Nanoscience and Nanotechnology (NEST), Scuola Normale Superiore and Istituto Nanoscienze, Consiglio Nazionale delle Ricerche (CNR), I-56126 Pisa (Italy); Pirandola, Stefano [Department of Computer Science, University of York, York YO10 5GH (United Kingdom); Mancini, Stefano [School of Science and Technology, University of Camerino, I-62032 Camerino (Italy); Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Perugia, I-06123 Perugia (Italy); Lloyd, Seth [Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2011-07-15

    We consider the problem of quantum communication mediated by a passive optical refocusing system. The model captures the basic features of all those situations in which a signal is either refocused by a repeater for long-distance communication, or it is focused on a detector prior to the information decoding process. Introducing a general method for linear passive optical systems, we determine the conditions under which optical refocusing implies information transmission gain. Although the finite aperture of the repeater may cause loss of information, we show that the presence of the refocusing system can substantially enhance the rate of reliable communication with respect to the free-space propagation. We explicitly address the transferring of classical messages over the quantum channel, but the results can be easily extended to include the case of transferring quantum messages as well.

  4. Enhanced quantum communication via optical refocusing

    Science.gov (United States)

    Lupo, Cosmo; Giovannetti, Vittorio; Pirandola, Stefano; Mancini, Stefano; Lloyd, Seth

    2011-07-01

    We consider the problem of quantum communication mediated by a passive optical refocusing system. The model captures the basic features of all those situations in which a signal is either refocused by a repeater for long-distance communication, or it is focused on a detector prior to the information decoding process. Introducing a general method for linear passive optical systems, we determine the conditions under which optical refocusing implies information transmission gain. Although the finite aperture of the repeater may cause loss of information, we show that the presence of the refocusing system can substantially enhance the rate of reliable communication with respect to the free-space propagation. We explicitly address the transferring of classical messages over the quantum channel, but the results can be easily extended to include the case of transferring quantum messages as well.

  5. Numerical refocusing of planar samples unlimited

    Science.gov (United States)

    Týč, Matěj; Chmelík, Radim

    2010-12-01

    This paper addresses the issue of numerical refocusing and its limits using the linear systems theory.Numerical refocusing is a well-known technique allowing looking above and below the focal plane of a sample in a manner similar to mechanically refocusing, but it can be used off-line. The most common implementation of this method is multiplication of angular spectrum of the recorded complex amplitude by the Fresnel propagating function. However, this approach is correct only in the case when monochromatic and spatially coherent illumination is used. Therefore it is not generally usable. If we concern ourselves with planar samples, we can afford to go into more details and we can perform the refocusing correctly, providing that we know imaging properties of the system in form of its transfer function. For instance, if we record the wave at a certain position, we can refocus as far as we want without introducing any error of this kind. Moreover, if we work with a binary approximation of the transfer function, we can derive a more general propagator that can be used to refocus under incoherent illumination with much more accurate results.

  6. Refocusing distance of a standard plenoptic camera.

    Science.gov (United States)

    Hahne, Christopher; Aggoun, Amar; Velisavljevic, Vladan; Fiebig, Susanne; Pesch, Matthias

    2016-09-19

    Recent developments in computational photography enabled variation of the optical focus of a plenoptic camera after image exposure, also known as refocusing. Existing ray models in the field simplify the camera's complexity for the purpose of image and depth map enhancement, but fail to satisfyingly predict the distance to which a photograph is refocused. By treating a pair of light rays as a system of linear functions, it will be shown in this paper that its solution yields an intersection indicating the distance to a refocused object plane. Experimental work is conducted with different lenses and focus settings while comparing distance estimates with a stack of refocused photographs for which a blur metric has been devised. Quantitative assessments over a 24 m distance range suggest that predictions deviate by less than 0.35 % in comparison to an optical design software. The proposed refocusing estimator assists in predicting object distances just as in the prototyping stage of plenoptic cameras and will be an essential feature in applications demanding high precision in synthetic focus or where depth map recovery is done by analyzing a stack of refocused photographs.

  7. Refocusing vibrating targets in SAR images

    Science.gov (United States)

    Wang, Qi; Santhanam, Balu; Pepin, Matthew; Atwood, Tom; Hayat, Majeed M.

    2012-06-01

    In synthetic-aperture radar (SAR) returned signals, ground-target vibrations introduce a phase modulation that is linearly proportional to the vibration displacement. Such modulation, termed the micro-Doppler effect, introduces ghost targets along the azimuth direction in reconstructed SAR images that prevents SAR from forming focused images of the vibrating targets. Recently, a discrete fractional Fourier transform (DFrFT) based method was developed to estimate the vibration frequencies and instantaneous vibration accelerations of the vibrating targets from SAR returned signals. In this paper, a demodulation-based algorithm is proposed to reconstruct focused SAR images of vibrating targets by exploiting the estimation results of the DFrFT-based vibration estimation method. For a single-component harmonic vibration, the history of the vibration displacement is first estimated from the estimated vibration frequency and the instantaneous vibration accelerations. Then a reference signal whose phase is modulated by the estimated vibration displacement with a delay of 180 degree is constructed. After that, the SAR phase history from the vibration target is multiplied by the reference signal and the vibration-induced phase modulation is canceled. Finally, the SAR image containing the re-focused vibration target is obtained by applying the 2-D Fourier transform to the demodulated SAR phase history. This algorithm is applied to simulated SAR data and successfully reconstructs the SAR image containing the re-focused vibrating target.

  8. Refocusing images and videos with a conventional compact camera

    Science.gov (United States)

    Kang, Lai; Wu, Lingda; Wei, Yingmei; Song, Hanchen; Yang, Zheng

    2015-03-01

    Digital refocusing is an interesting and useful tool for generating dynamic depth-of-field (DOF) effects in many types of photography such as portraits and creative photography. Since most existing digital refocusing methods rely on four-dimensional light field captured by special precisely manufactured devices or a sequence of images captured by a single camera, existing systems are either expensive for wide practical use or incapable of handling dynamic scenes. We present a low-cost approach for refocusing high-resolution (up to 8 mega pixels) images and videos based on a single shot using an easy to build camera-mirror stereo system. Our proposed method consists of four main steps, namely system calibration, image rectification, disparity estimation, and refocusing rendering. The effectiveness of our proposed method has been evaluated extensively using both static and dynamic scenes with various depth ranges. Promising experimental results demonstrate that our method is able to simulate various controllable realistic DOF effects. To the best of our knowledge, our method is the first that allows one to refocus high-resolution images and videos of dynamic scenes captured by a conventional compact camera.

  9. THE APPLICATION OF AN ENGINEERING BASED METHODOLOGY TO ORGANISATIONAL DIVERSIFICATION AND REFOCUSING - AN OVERVIEW

    National Research Council Canada - National Science Library

    Leonard, Pierre; Kruger, Paul

    2012-01-01

    .... Although various leading authors, top business professionals and consulting groups have different opinions regarding the use of diversification and refocusing, these seem to be alternative ways...

  10. Filtered refocusing: a volumetric reconstruction algorithm for plenoptic-PIV

    Science.gov (United States)

    Fahringer, Timothy W.; Thurow, Brian S.

    2016-09-01

    A new algorithm for reconstruction of 3D particle fields from plenoptic image data is presented. The algorithm is based on the technique of computational refocusing with the addition of a post reconstruction filter to remove the out of focus particles. This new algorithm is tested in terms of reconstruction quality on synthetic particle fields as well as a synthetically generated 3D Gaussian ring vortex. Preliminary results indicate that the new algorithm performs as well as the MART algorithm (used in previous work) in terms of the reconstructed particle position accuracy, but produces more elongated particles. The major advantage to the new algorithm is the dramatic reduction in the computational cost required to reconstruct a volume. It is shown that the new algorithm takes 1/9th the time to reconstruct the same volume as MART while using minimal resources. Experimental results are presented in the form of the wake behind a cylinder at a Reynolds number of 185.

  11. Development of the REFOCUS intervention to increase mental health team support for personal recovery.

    Science.gov (United States)

    Slade, Mike; Bird, Victoria; Le Boutillier, Clair; Farkas, Marianne; Grey, Barbara; Larsen, John; Leamy, Mary; Oades, Lindsay; Williams, Julie

    2015-12-01

    There is an emerging evidence base about best practice in supporting recovery. This is usually framed in relation to general principles, and specific pro-recovery interventions are lacking. To develop a theoretically based and empirically defensible new pro-recovery manualised intervention--called the REFOCUS intervention. Seven systematic and two narrative reviews were undertaken. Identified evidence gaps were addressed in three qualitative studies. The findings were synthesised to produce the REFOCUS intervention, manual and model. The REFOCUS intervention comprises two components: recovery-promoting relationships and working practices. Approaches to supporting relationships comprise coaching skills training for staff, developing a shared team understanding of recovery, exploring staff values, a Partnership Project with people who use the service and raising patient expectations. Working practices comprise the following: understanding values and treatment preferences; assessing strengths; and supporting goal-striving. The REFOCUS model describes the causal pathway from the REFOCUS intervention to improved recovery. The REFOCUS intervention is an empirically supported pro-recovery intervention for use in mental health services. It will be evaluated in a multisite cluster randomised controlled trial (ISRCTN02507940). © The Royal College of Psychiatrists 2015.

  12. Development of in-orbit refocusing mechanism for SpaceEye-1 electro-optical payload

    Science.gov (United States)

    Lee, Minwoo; Kim, Jongun; Chang, Jin-Soo; Kang, Myung-Seok

    2016-09-01

    SpaceEye-1 earth observation satellite, developed by Satrec Initiative Co. Ltd., is a 300 kg scale spacecraft with high resolution electro-optical payload (EOS-D) which performs 1 m GSD, 12 km swath in low earth orbit. Metering structure of EOS-D is manufactured with Carbon Fiber Reinforced Plastic (CFRP). Due to the moisture emission from CFRP metering structure, this spaceborne electro-optical payload undergoes shrinkage after orbit insertion. The shrinkage of metering structure causes change of the distance between primary and secondary mirror. In order to compensate the moisture shrinkage effect, two types of thermal refocusing mechanism were developed, analyzed and applied to EOS-D. Thermal analysis simulating in-orbit thermal condition and thermo-elastic displacement analysis was conducted to calculate the performance of refocusing mechanism. For each EOS-D telescope, analytical refocusing range (displacement change between primary and secondary mirror) was 2.5 um and 3.6 um. Thus, the refocusing mechanism can compensate the dimensional instability of metering structure caused by moisture emission. Furthermore, modal, static and wavefront error analysis was conducted in order to evaluate natural frequency, structural stability and optical performance. As a result, it can be concluded that the refocusing system of EOS-D payload can perform its function in orbit.

  13. Non-Selective Lexical Access in Different-Script Bilinguals

    Science.gov (United States)

    Moon, Jihye; Jiang, Nan

    2012-01-01

    Lexical access in bilinguals is known to be largely non-selective. However, most studies in this area have involved bilinguals whose two languages share the same script. This study aimed to examine bilingual lexical access among bilinguals whose two languages have distinct scripts. Korean-English bilinguals were tested in a phoneme monitoring task…

  14. Highly efficient (19)F heteronuclear decoupling in solid-state NMR spectroscopy using supercycled refocused-CW irradiation.

    Science.gov (United States)

    Equbal, Asif; Basse, Kristoffer; Nielsen, Niels Chr

    2016-12-07

    We present heteronuclear (19)F refocused CW (rCW) decoupling pulse sequences for solid-state magic-angle-spinning NMR applications. The decoupling sequences have been designed specifically to ensure suppression of the pertinent (13)C-(19)F dipolar coupling interactions while simultaneously suppressing strong anisotropic chemical shift as well as homonuclear (19)F-(19)F dipolar coupling effects as typically present in perfluorated compounds. In an extensive numerical and experimental analysis using a rigid, organic solid as a model compound, it becomes evident that the supercycled rCW schemes markedly improve the decoupling efficiency, leading to substantial enhancements in resolution and sensitivity when compared to previous state-of-the-art methods. Furthermore, considerable gains in robustness toward rf mismatch as well as offset in the radio-frequency carrier frequency are observed, all of which clearly render the new rCW schemes the methods of choice for (19)F decoupling in rigid, fluorinated compounds - which is further supported by a Floquet-based theoretical analysis.

  15. Development of an in-orbit refocusing mechanism for the meteosat second generation weather satellites

    NARCIS (Netherlands)

    Verhoeff, P.; Mierlo, H.A. van; Braam, B.C.; Hopman, J.; Werkhoven, W.P. van; Kluse, M. le

    1998-01-01

    A Refocusing Mechanism (REM) has been designed and built for the SEVIRI instrument, the imager in the Meteosat Second Generation (MSG) satellite. The purpose of the mechanism is in-orbit focal adjustment of a mirror assembly which forms part of SEVIRI. As the MSG satellite observes the earth and its

  16. A rapid magnetic resonance acoustic radiation force imaging sequence for ultrasonic refocusing

    Science.gov (United States)

    Mougenot, Charles; Pichardo, Samuel; Engler, Steven; Waspe, Adam; Constanciel Colas, Elodie; Drake, James M.

    2016-08-01

    Magnetic resonance guided acoustic radiation force imaging (MR-ARFI) is being used to correct for aberrations induced by tissue heterogeneities when using high intensity focusing ultrasound (HIFU). A compromise between published MR-ARFI adaptive solutions is proposed to achieve efficient refocusing of the ultrasound beam in under 10 min. In addition, an ARFI sequence based on an EPI gradient echo sequence was used to simultaneously monitor displacement and temperature with a large SNR and low distortion. This study was conducted inside an Achieva 3T clinical MRI using a Philips Sonalleve MR-HIFU system to emit a 1 ms pulsed sonication with duty cycle of 2.3% at 300 Wac inside a polymer phantom. Virtual elements defined by a Hadamard array with sonication patterns composed of 6 phase steps were used to characterize 64 groups of 4 elements to find the optimal phase of the 256 elements of the transducer. The 384 sonication patterns were acquired in 580 s to identify the set of phases that maximize the displacement at the focal point. Three aberrators (neonatal skull, 8 year old skull and a checkered pattern) were added to each sonication pattern to evaluate the performance of this refocusing algorithm (n  =  4). These aberrators reduced the relative intensities to 95.3%, 69.6% and 25.5% for the neonatal skull, 8 year old skull, and checkered pattern virtual aberrators respectively. Using a 10 min refocusing algorithm, relative intensities of 101.6%, 91.3% and 93.3% were obtained. Better relative intensities of 103.9%, 94.3% and 101% were achieved using a 25 min refocusing algorithm. An average temperature increase of 4.2 °C per refocusing test was induced for the 10 min refocusing algorithm, resulting in a negligible thermal dose of 2 EM. A rapid refocusing of the beam can be achieved while keeping thermal effects to a minimum.

  17. Refocusing from a plenoptic camera within seconds on a mobile phone

    Science.gov (United States)

    Gómez-Cárdenes, Ã.`scar; Marichal-Hernández, José G.; Rosa, Fernando L.; Lüke, Jonas P.; Fernández-Valdivia, Juan José; Rodríguez-Ramos, José M.

    2014-05-01

    Refocusing a plenoptic image by digital means and after the exposure has been thoroughly studied in the last years, but few efforts have been made in the direction of real time implementation in a constrained environment such as that provided by current mobile phones and tablets. In this work we address the aforementioned challenge demonstrating that a complete focal stack, comprising 31 refocused planes from a (256ff16)2 plenoptic image, can be achieved within seconds by a current SoC mobile phone platform. The election of an appropriate algorithm is the key to success. In a previous work we developed an algorithm, the fast approximate 4D:3D discrete Radon transform, that performs this task with linear time complexity where others obtain quadratic or linearithmic time complexity. Moreover, that algorithm does not requires complex number transforms, trigonometric calculus nor even multiplications nor oat numbers. Our algorithm has been ported to a multi core ARM chip on an off-the-shelf tablet running Android. A careful implementation exploiting parallelism at several levels has been necessary. The final implementation takes advantage of multi-threading in native code and NEON SIMD instructions. As a result our current implementation completes the refocusing task within seconds for a 16 megapixels image, much faster than previous attempts running on powerful PC platforms or dedicated hardware. The times consumed by the different stages of the digital refocusing are given and the strategies to achieve this result are discussed. Time results are given for a variety of environments within Android ecosystem, from the weaker/cheaper SoCs to the top of the line for 2013.

  18. Refocusing of Moving Targets in SAR Images via Parametric Sparse Representation

    Directory of Open Access Journals (Sweden)

    Yichang Chen

    2017-08-01

    Full Text Available In this paper, a parametric sparse representation (PSR method is proposed for refocusing of moving targets in synthetic aperture radar (SAR images. In regular SAR images, moving targets are defocused due to unknown motion parameters. Refocusing of moving targets requires accurate phase compensation of echo data. In the proposed method, the region of interest (ROI data containing the moving targets are extracted from the complex SAR image and represented in a sparse fashion through a parametric transform, which is related to the phase compensation parameter. By updating the reflectivities of moving target scatterers and the parametric transform in an iterative fashion, the phase compensation parameter can be accurately estimated and the SAR images of moving targets can be refocused well. The proposed method directly operates on small-size defocused ROI data, which helps to reduce the computational burden and suppress the clutter. Compared to other existing ROI-based methods, the proposed method can suppress asymmetric side-lobes and improve the image quality. Both simulated data and real SAR data collected by GF-3 satellite are used to validate the effectiveness of the proposed method.

  19. Refractive index measurements of multiple layers using numerical refocusing in FF-OCT.

    Science.gov (United States)

    Min, Gihyeon; Choi, Woo June; Kim, Ju Wan; Lee, Byeong Ha

    2013-12-02

    We propose and demonstrate the novel method of refractive index (RI) measurement for each layer of multilayered samples, which is based on numerical refocusing in full field optical coherence tomography (FF-OCT). The en-face FF-OCT image on an inner layer boundary of a multilayered sample is unintentionally blurred or defocused due to the RI of the sample itself, but can be numerically refocused. The refocusing is performed by numerically shifting the image sensor plane of the system, in general. However, by calculating the corresponding sample shift and then compared it with the actual sample shifting distance, we could extract the average RI of the layer between any two layer boundaries within the multilayered sample. In addition, the thickness of that particular layer could be derived at the same time. For the idea proof, several samples were prepared by stacking, for each sample, two transparent plates with a gap in between. While changing the material of the plate and filling the gap with oil, the RIs of the plate and the oil were measured. For oils of various RIs, from 1.2977 to 1.3857, the measured RIs were well matched with the reported ones within 0.205%. Moreover, even with a stack of various and multiple plates in front of the same oil layer, the oil RI and the physical thickness of the oil layer were extracted with average errors of only 0.065% and 0.990%, respectively.

  20. Robust and efficient 19F heteronuclear dipolar decoupling using refocused continuous-wave rf irradiation

    Science.gov (United States)

    Vinther, Joachim M.; Khaneja, Navin; Nielsen, Niels Chr.

    2013-01-01

    Refocused continuous wave (rCW) decoupling is presented as an efficient and robust means to obtain well-resolved magic-angle-spinning solid-state NMR spectra of low-γ spins, such as 13C dipolar coupled to fluorine. The rCW decoupling sequences, recently introduced for 1H decoupling, are very robust towards large isotropic and anisotropic shift ranges as often encountered for 19F spins. In rCW decoupling, the so-called refocusing pulses inserted into the CW irradiation eliminate critical residual second- and third-order dipolar coupling and dipolar-coupling against chemical shielding anisotropy cross-terms in the effective Hamiltonian through time-reversal (i.e. refocusing). As important additional assets, the rCW decoupling sequences are robust towards variations in rf amplitudes, operational at low to high spinning speeds, and easy to set-up for optimal performance experimentally. These aspects are demonstrated analytically/numerically and experimentally in comparison to state-of-the-art decoupling sequences such as TPPM, SPINAL-64, and frequency-swept variants of these.

  1. The Influence of Neurolinguistic Applications on Second Language Research: Reviewing the Issues and Refocusing the Debate

    Directory of Open Access Journals (Sweden)

    Masoud Mahmoodzadeh

    2015-03-01

    Full Text Available The influence of neurolinguistic applications on second language pedagogy has often been a controversial subject of dispute. As such, researchers in this field have faced with some blurred and conflicting views in terms of the pedagogical applicability of neurological discoveries for second language instruction. In light of this research-based concern, the current short paper attempts to review the related issues and refocus the current direction of the neurolinguistic-second language pedagogy debate. The paper also concludes with some suggestions made in favor of an alternative neurolinguistic outlook for L2 researchers.

  2. Radio Journalism.

    Science.gov (United States)

    Bittner, John R.; Bittner, Denise A.

    This book, a how-to-do-it guide for the novice and the professional alike, deals with several aspects of radio journalism: producing documentaries, preparing and announcing radio news, ethics and responsibility, regulation of radio journalism, and careers. It traces the history and growth of radio news, shows its impact on the public, and…

  3. Ibudilast: a non-selective phosphodiesterase inhibitor in brain disorders

    Directory of Open Access Journals (Sweden)

    Joanna Schwenkgrub

    2017-03-01

    Full Text Available Ibudilast (IBD is a non-selective (3, 4, 10, 11 phosphodiesterase (PDE inhibitor, used mainly as a bronchodilator for the treatment of bronchial asthma. PDE play a central role in cellular function (e.g. differentiation, synaptic plasticity and inflammatory response by metabolizing cyclic nucleotides. The results from preclinical and clinical studies indicate that IBD has a broader range of action through suppression of pro-inflammatory cytokines (IL-6, IL-1β, TNF-α, toll-like receptor 4 blockade (TLR-4, inhibition of a macrophage migration inhibitory factor (MIF, up-regulation the anti-inflammatory cytokine (IL-10, and promotion of neurotrophic factors (GDNF, NGF, NT-4. Recent data indicate that the efficacy of IBD appears to be independent from PDE inhibition activity and rather linked to glial activity attenuation. Additional advantages of IBD, such as crossing the blood–brain barrier, good tolerance and activity by oral administration, makes it a promising therapeutic candidate for treating neuroinflammatory conditions, where the currently available treatment remains unsatisfying due to poor tolerability and/or sub-optimal efficacy. IBD has no direct receptor affinity with exemption of some undefined effect on adenosine receptors that makes the drug devoid of its receptors-mediated adverse effects. Current article provides an overview of the pharmacology of IBD with a focus on preclinical and clinical data supporting its potential neuroprotective benefits for neurological conditions, including multiple sclerosis, neuropathic pain, medication overuse headache, stroke, opioid, alcohol and methamphetamine abuse.

  4. J-refocused 1H PRESS DEPT for localized 13C MR spectroscopy.

    Science.gov (United States)

    Chen, X; Boesiger, P; Henning, A

    2013-09-01

    Proton point-resolved spectroscopy (PRESS) localization has been combined with distortionless enhanced polarization transfer (DEPT) in multinuclear MRS to overcome the signal contamination problem in image-selected in vivo spectroscopy (ISIS)-combined DEPT, especially for lipid detection. However, homonuclear proton scalar couplings reduce the DEPT enhancement by modifying the spin coherence distribution under J modulation during proton PRESS localization. Herein, a J-refocused proton PRESS-localized DEPT sequence is presented to obtain simultaneously enhanced and localized signals from a large number of metabolites by in vivo (13) C MRS. The suppression of J modulation during PRESS and the substantial recovery of signal enhancement by J-refocused PRESS-localized DEPT were demonstrated theoretically by product operator formalism, numerically by the spin density matrix simulations for different scalar coupling conditions, and experimentally with a glutamate phantom at various TEs, as well as a colza oil phantom. The application of the sequence for localized detection of saturated and unsaturated fatty acids in the calf bone marrow and skeletal muscle of healthy subjects yielded high signal enhancements simultaneously obtained for all components.

  5. Highly efficient F-19 heteronuclear decoupling in solid-state NMR spectroscopy using supercycled refocused-CW irradiation

    DEFF Research Database (Denmark)

    Equbal, Asif; Basse, Kristoffer; Nielsen, Niels Christian

    2016-01-01

    We present heteronuclear F-19 refocused CW (rCW) decoupling pulse sequences for solid-state magic-angle- spinning NMR applications. The decoupling sequences have been designed specifically to ensure suppression of the pertinent C-13-F-19 dipolar coupling interactions while simultaneously suppress......We present heteronuclear F-19 refocused CW (rCW) decoupling pulse sequences for solid-state magic-angle- spinning NMR applications. The decoupling sequences have been designed specifically to ensure suppression of the pertinent C-13-F-19 dipolar coupling interactions while simultaneously...

  6. Refocused continuous-wave decoupling: A new approach to heteronuclear dipolar decoupling in solid-state NMR spectroscopy

    Science.gov (United States)

    Vinther, Joachim M.; Nielsen, Anders B.; Bjerring, Morten; van Eck, Ernst R. H.; Kentgens, Arno P. M.; Khaneja, Navin; Nielsen, Niels Chr.

    2012-12-01

    A novel strategy for heteronuclear dipolar decoupling in magic-angle spinning solid-state nuclear magnetic resonance (NMR) spectroscopy is presented, which eliminates residual static high-order terms in the effective Hamiltonian originating from interactions between oscillating dipolar and anisotropic shielding tensors. The method, called refocused continuous-wave (rCW) decoupling, is systematically established by interleaving continuous wave decoupling with appropriately inserted rotor-synchronized high-power π refocusing pulses of alternating phases. The effect of the refocusing pulses in eliminating residual effects from dipolar coupling in heteronuclear spin systems is rationalized by effective Hamiltonian calculations to third order. In some variants the π pulse refocusing is supplemented by insertion of rotor-synchronized π/2 purging pulses to further reduce the residual dipolar coupling effects. Five different rCW decoupling sequences are presented and their performance is compared to state-of-the-art decoupling methods. The rCW decoupling sequences benefit from extreme broadbandedness, tolerance towards rf inhomogeneity, and improved potential for decoupling at relatively low average rf field strengths. In numerical simulations, the rCW schemes clearly reveal superior characteristics relative to the best decoupling schemes presented so far, which we to some extent also are capable of demonstrating experimentally. A major advantage of the rCW decoupling methods is that they are easy to set up and optimize experimentally.

  7. Refocusing core intuitions: A concretizing role for analogy in conceptual change

    Science.gov (United States)

    Brown, David E.

    1993-12-01

    This article outlines a theoretical framework for viewing students' conceptions and the effect of analogies on students' conceptions. There are several points involved in this perspective: (a) Components of students' conceptions can be considered to be at various levels - verbal-symbolic knowledge, conscious models, implicit models, and core intuitions. (b) Components at the deeper, less articulated levels (especially core intuitions) are particularly entrenched. (c) Conceptual change in cases involving core intuitions can be considered to be the adjustment of attributive clusters for a class of situations. (d) In order to change the attributive cluster for a target situation, the target must be enriched with new concrete entities or features, providing nuclei for the reattribution of agency. (e) Analogies can help with this reattribution or refocusing by helping the student enrich his or her representation of the target situation.

  8. Service user experiences of REFOCUS: a process evaluation of a pro-recovery complex intervention.

    Science.gov (United States)

    Wallace, Genevieve; Bird, Victoria; Leamy, Mary; Bacon, Faye; Le Boutillier, Clair; Janosik, Monika; MacPherson, Rob; Williams, Julie; Slade, Mike

    2016-09-01

    Policy is increasingly focused on implementing a recovery-orientation within mental health services, yet the subjective experience of individuals receiving a pro-recovery intervention is under-studied. The aim of this study was to explore the service user experience of receiving a complex, pro-recovery intervention (REFOCUS), which aimed to encourage the use of recovery-supporting tools and support recovery-promoting relationships. Interviews (n = 24) and two focus groups (n = 13) were conducted as part of a process evaluation and included a purposive sample of service users who received the complex, pro-recovery intervention within the REFOCUS randomised controlled trial (ISRCTN02507940). Thematic analysis was used to analyse the data. Participants reported that the intervention supported the development of an open and collaborative relationship with staff, with new conversations around values, strengths and goals. This was experienced as hope-inspiring and empowering. However, others described how the recovery tools were used without context, meaning participants were unclear of their purpose and did not see their benefit. During the interviews, some individuals struggled to report any new tasks or conversations occurring during the intervention. Recovery-supporting tools can support the development of a recovery-promoting relationship, which can contribute to positive outcomes for individuals. The tools should be used in a collaborative and flexible manner. Information exchanged around values, strengths and goals should be used in care-planning. As some service users struggled to report their experience of the intervention, alternative evaluation approaches need to be considered if the service user experience is to be fully captured.

  9. High-speed, digitally refocused retinal imaging with line-field parallel swept source OCT

    Science.gov (United States)

    Fechtig, Daniel J.; Kumar, Abhishek; Ginner, Laurin; Drexler, Wolfgang; Leitgeb, Rainer A.

    2015-03-01

    MHz OCT allows mitigating undesired influence of motion artifacts during retinal assessment, but comes in state-of-the-art point scanning OCT at the price of increased system complexity. By changing the paradigm from scanning to parallel OCT for in vivo retinal imaging the three-dimensional (3D) acquisition time is reduced without a trade-off between speed, sensitivity and technological requirements. Furthermore, the intrinsic phase stability allows for applying digital refocusing methods increasing the in-focus imaging depth range. Line field parallel interferometric imaging (LPSI) is utilizing a commercially available swept source, a single-axis galvo-scanner and a line scan camera for recording 3D data with up to 1MHz A-scan rate. Besides line-focus illumination and parallel detection, we mitigate the necessity for high-speed sensor and laser technology by holographic full-range imaging, which allows for increasing the imaging speed by low sampling of the optical spectrum. High B-scan rates up to 1kHz further allow for implementation of lable-free optical angiography in 3D by calculating the inter B-scan speckle variance. We achieve a detection sensitivity of 93.5 (96.5) dB at an equivalent A-scan rate of 1 (0.6) MHz and present 3D in vivo retinal structural and functional imaging utilizing digital refocusing. Our results demonstrate for the first time competitive imaging sensitivity, resolution and speed with a parallel OCT modality. LPSI is in fact currently the fastest OCT device applied to retinal imaging and operating at a central wavelength window around 800 nm with a detection sensitivity of higher than 93.5 dB.

  10. Radio archive

    OpenAIRE

    Street, Sean

    2008-01-01

    The Centre for Broadcasting History Research, in association with the\\ud British Universities Film and Video Council, is developing an online\\ud audio archive of UK commercial radio, from 1973 to 1992. Work produced\\ud before the Broadcasting Act 1990 represents a different ethos to the role\\ud commercial radio played, and subsequently,continues to play, in the UK.\\ud The change in commercial radio since this period is extraordinary. It is\\ud impossible for the young student of radio, born si...

  11. Refocusing formative feedback to enhance learning in pre-registration nurse education.

    Science.gov (United States)

    Koh, Lai Chan

    2008-07-01

    The essential feature of a teaching system designed to enhance learning and emulate professional practice is that the crucial assessments should be performance-based, allowing plenty of opportunity for students to offer their own ideas and solutions. This involves the use of formative assessment and feedback. High quality formative assessment has been linked to enhancement of learning and ultimately to higher student achievement. Although formative assessment is acknowledged as important in its effect on students' approaches to learning, it appears that the assessment practice is under utilized in pre-registration nurse education. This paper refocuses on the purpose of formative assessment of theory. It examines, from educational literature, some of the benefits of formative assessment and its pedagogical implications on deep learning, motivation and self-esteem, self-regulated learning and employability. It discusses what constitutes quality feedback to highlight that it is not just an essential component but also a central feature of formative assessment. The extent to which formative assessment and feedback can be applied to pre-registration nurse education is also explored. If formative assessment and feedback is well planned and conducted in assessment practice, it is suggested that effective learning can be facilitated in everyday learning activity.

  12. International Council of Ophthalmology: Refocusing Ophthalmic Education in the Asia-Pacific Region and Beyond.

    Science.gov (United States)

    Golnik, Karl; Mayorga, Eduardo; Spivey, Bruce; Ritch, Robert; Gauthier, Tina-Marie

    2012-01-01

    The International Council of Ophthalmology (ICO) is a global organization with a regional focus. Working in partnership with supranational and ICO member societies, the ICO is building a "World Alliance for Sight" to improve access to the highest-quality eye care worldwide. Designed to preserve and restore vision on an international scale, the ICO initiative, "Refocusing Ophthalmic Education," enhances ophthalmic education of residents, subspecialists, medical students, and allied eye care personnel by redefining the most effective ways to teach and in creating beneficial educational opportunities. The "Teaching the Teachers" program helps ophthalmic educators incorporate more effective methods of training and continuing professional development to meet societal needs, achieved in part through regional courses for residency program directors; symposia, and keynote talks presented by ICO's World Ophthalmology Educational Colloquium, Conferences for Ophthalmic Educators, and ophthalmic surgical competency rubrics. Recognizing that standardized curricula are essential for consistent ophthalmic education, the ICO has developed a curricular framework whereby goals, expectations, knowledge base, competencies, and technical training are delineated. The ICO is defining worldwide models of team training and compiling best practice, which will include training-program accreditation to ensure improvement in the education of ophthalmologists. International Council of Ophthalmology Web-based teaching courses, a Webinar Network, and a technology blog further support information and communication technologies for teaching and learning. At the ICO's Center for Ophthalmic Educators (educators.icoph.org), trainers will find valuable teaching resources in multiple languages as well as ways to share ideas and collaborate with peers and other ophthalmic educators.

  13. Cognitive refocusing treatment for insomnia: a randomized controlled trial in university students.

    Science.gov (United States)

    Gellis, Les A; Arigo, Danielle; Elliott, Jennifer C

    2013-03-01

    This investigation assessed the efficacy of a technique specifically designed to change the style and content of presleep thoughts in order to reduce nighttime cognitive arousal and decrease insomnia severity. This investigation, termed "cognitive refocusing treatment for insomnia" (CRT-I), previously improved sleep in a small sample of veterans with primary insomnia. In this investigation, university students with poor sleep were randomly assigned to attend either one session of CRT-I and sleep hygiene education (SH: n=27) or one session of only SH (n=24). Insomnia severity (assessed by the Insomnia Severity Index) and nighttime arousal (assessed by the Pre-Sleep Arousal Scale) were measured at baseline and 1month posttreatment. A significant Group×Time interaction for insomnia severity suggested more improved sleep over time for those receiving CRT-I+SH. A trend for a Group×Time interaction showed decreased cognitive arousal over time among those receiving CRT-I. These findings provide preliminary support for the efficacy of CRT-I for insomnia treatment among college students. Continued study of CRT-I in a community-based sample appears warranted.

  14. MRI measurement of blood-brain barrier transport with a rapid acquisition refocused echo (RARE) method

    Science.gov (United States)

    Walton, Jeffrey H; Ng, Kit Fai; Anderson, Steven E; Rutledge, John C

    2015-01-01

    Dynamic Contrast Enhanced (DCE) MRI is increasingly being used to assess changes in capillary permeability. Most quantitative techniques used to measure capillary permeability are based on the Fick equation that requires measurement of signal reflecting both plasma and tissue concentrations of the solute being tested. To date, most Magnetic Resonance Imaging (MRI) methods for acquiring appropriate data quickly rely on gradient recalled echo (GRE) type acquisitions, which work well in clinical low field settings. However, acquiring this type of data on high field small animal preclinical MRIs is problematic due to geometrical distortions from susceptibility mismatch. This problem can be exacerbated when using small animal models to measure blood brain barrier (BBB) permeability, where precise sampling from the superior sagittal sinus (SSS) is commonly used to determine the plasma concentration of the contrast agent. Here we present results demonstrating that a standard saturation recovery rapid acquisition refocused echo (RARE) method is capable of acquiring T1 maps with good spatial and temporal resolution for Patlak analysis (Patlak, 1983) to assess changes in BBB Gd-DTPA permeability following middle cerebral artery occlusion with reperfusion in the rat. This method limits known problems with magnetic susceptibility mismatch and may thus allow greater accuracy in BBB permeability measurement in small animals. PMID:25998382

  15. Radio Eska Lodz, Commercial Radio As a Local Radio

    OpenAIRE

    Szews, Przemysław

    2015-01-01

    The article discusses aspects of network-based local radio using the example of Radio Eska Lodz. The author responds to questions about whether a commercial network radio station can fulfill the functions of local radio and on what this locality is actually based. In this respect, Radio Eska Lodz is characterized as part of the most popular commercial radio network in Poland. The introduction focuses on the process of transformation that local radio stations are undergoing, along with its gen...

  16. Solar Radio

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Scientists monitor the structure of the solar corona, the outer most regions of the Sun's atmosphere, using radio waves (100?s of MHz to 10?s of GHz). Variations in...

  17. Refocusing Seafood Sustainability as a Journey Using the Law of the Minimum

    Directory of Open Access Journals (Sweden)

    Elizabeth Fitzsimons

    2012-08-01

    Full Text Available Globally, seafood is an important protein source because it is a nutritious food source produced with relative efficiency compared to other proteins. Because of problems related to overfishing and deleterious environmental impacts, over the last decade, non-governmental organizations (NGOs have increased their focus on seafood sustainability while businesses have incorporated this issue into their corporate social responsibility (CSR reporting. Sustainability is a concept that can be addressed in terms of scale of issues considered (narrow vs. broad as well as the scope of how they are measured (undemanding or demanding. Currently, the message of seafood sustainability is becoming complicated in that the journey toward sustainability is being referred to as having achieved a state of sustainability. In addition, companies making a “sustainable” declaration are often at different points in the “scale/scope” arena. As a result, buyers, retailers and consumers have difficulty differentiating between these products. Furthermore, they often assume that a “sustainable” product has no further need for improvement, when in fact this is rarely the case. This change in reference from a continual process (a journey to a static point (it is sustainable limits further advances in seafood sustainability and the drive for continual improvement. Herein, the “Law of the Minimum”, growth toward an end goal will occur until one factor becomes limiting, is adopted as an analogy for sustainability. By refocusing the sustainability discussion on a progressive series of challenges to be met, the discussion will return to the journey as the central point. Doing so will help refresh the dialogue around seafood, and to create new opportunities for improvement.

  18. Can non-selective beta-blockers prevent hepatocellular carcinoma in patients with cirrhosis?

    DEFF Research Database (Denmark)

    Thiele, Maja; Wiest, Reiner; Gluud, Lise Lotte

    2013-01-01

    Hepatocellular carcinoma is the main liver-related cause of death in patients with compensated cirrhosis. The early phases are asymptomatic and the prognosis is poor, which makes prevention essential. We propose that non-selective beta-blockers decrease the incidence and growth of hepatocellular...... carcinoma via a reduction of the inflammatory load from the gut to the liver and inhibition of angiogenesis. Due to their effect on the portal pressure, non-selective beta-blockers are used for prevention of esophageal variceal bleeding. Recently, non-hemodynamic effects of beta-blockers have received...... reduce hepatic inflammation. Blockage of β-adrenoceptors also decrease angiogenesis by inhibition of vascular endothelial growth factors. Because gut-derived inflammation and neo-angiogenesis are important in hepatic carcinogenesis, non-selective beta-blockers can potentially reduce the development...

  19. How to sell successfully a perfume in the non-selective market?

    OpenAIRE

    Ramalho, Maria Rita Pinto Coelho de Magalhães

    2009-01-01

    A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics This document presents a market research on the positioning of perfumes in the non selective market. This project’s main goal had been to analyze the challenge of “successfully selling a perfume in the non-selective market” in order to propose potential solutions. To address this marketing problem, an exploratory research had been c...

  20. Radio astronomy

    CERN Document Server

    Alder, Berni

    1975-01-01

    Methods in Computational Physics, Volume 14: Radio Astronomy is devoted to the role of the digital computer both as a control device and as a calculator in addressing problems related to galactic radio noise. This volume contains four chapters and begins with a technical description of the hardware and the special data-handling problems of using radioheliography, with an emphasis on a selection of observational results obtained with the Culgoora radioheliograph and their significance to solar physics and to astrophysics in general. The subsequent chapter examines interstellar dispersion, i

  1. Digitale radio

    NARCIS (Netherlands)

    Schiphorst, Roel; Zondervan, L.

    2007-01-01

    Als eerste in Europa heeft Nederland begin december 2006 de omschakeling van analoge naar digitale ethertelevisie gemaakt. Voor de analoge FM-radio is er ook een digitale variant, T-DAB. T-DAB staat voor 'Terrestrial Digital Audio Broadcasting'. Dit artikel gaat verder in op deze techniek en de veld

  2. Non-selective β-blockers do not affect mortality in cirrhosis patients with ascites

    DEFF Research Database (Denmark)

    Bossen, Lars; Krag, Aleksander; Vilstrup, Hendrik

    2016-01-01

    The safety of non-selective β-blockers (NSBBs) in advanced cirrhosis has been questioned. We used data from three satavaptan trials to examine whether NSBBs increase mortality in cirrhosis patients with ascites. The trials were conducted in 2006-2008 and included 1198 cirrhosis patients with asci...

  3. Non-selective beta-blockers decrease thrombotic events in patients with heart failure

    NARCIS (Netherlands)

    De Peuter, Olav R.; Souverein, Patrick C.; Klungel, Olaf H.; Lip, Gregory Y.; Buller, Harry R.; De Boer, Anthonius; Kamphuisen, Pieter W.

    2010-01-01

    Background: Beta-blockers are often prescribed to patients with heart failure (HF) without distinctions between types of beta-blockers. The 2002 COMET study showed superiority of carvedilol (a non-selective beta-blocker) over metoprolol (selective beta-blocker) on mortality and cardiovascular events

  4. Time-Chunking and Hyper-Refocusing in a Digitally-Enabled Workplace: Six Forms of Knowledge Workers.

    Science.gov (United States)

    Gaskin, James E; Skousen, Tanner

    2016-01-01

    Until the turn of the millennium, switching tasks required moving locations or reconfiguring physical workspaces. However, contemporary digital tools and workspaces allow knowledge workers to perform an increasingly diverse set of tasks, with an increasingly extending arm of influence, all from the same physical location without any physical reconfigurations or traversing of physical space. Along with this increased ambidexterity comes an increase in the quantity and frequency of demands on the time of knowledge workers. This digitalization of work now tethers their ability to perform largely to their ability to intensely focus in small chunks, and then "hyper-jump" that focus to another task without traversing the cognitive cool downs or warm ups required to reconfigure their train of thought from one task to another. Accordingly, they must become more like the hyper-functioning tools they employ if they are to avoid becoming the bottleneck resource in the configuration of socio-technical elements comprising their work routines. In order to better understand how knowledge workers manage their time and maintain focus across multiple and interrupting tasks, we leverage current time prioritization literature to propose and theorize around two key constructs: time-chunking and hyper-refocusing. By combining the possible values for these two constructs, we hypothesize the emergence of six forms of knowledge workers and their relative expected performance. The effects of digitalization on these new worker forms are discussed. We conclude by discussing opportunities for new research questions regarding time-chunking strategies and the hyper-refocusing ability.

  5. The Radio JOVE Project - Shoestring Radio Astronomy

    Science.gov (United States)

    Thieman, J.; Flagg, R.; Greenman, W.; Higgins, C.; Reyes, F.; Sky, J.

    2010-01-01

    Radio JOVE is an education and outreach project intended to give students and other interested individuals hands-on experience in learning radio astronomy. They can do this through building a radio telescope from a relatively inexpensive kit that includes the parts for a receiver and an antenna as well as software for a computer chart recorder emulator (Radio Skypipe) and other reference materials

  6. The Radio JOVE Project - Shoestring Radio Astronomy

    Science.gov (United States)

    Thieman, J.; Flagg, R.; Greenman, W.; Higgins, C.; Reyes, F.; Sky, J.

    2010-01-01

    Radio JOVE is an education and outreach project intended to give students and other interested individuals hands-on experience in learning radio astronomy. They can do this through building a radio telescope from a relatively inexpensive kit that includes the parts for a receiver and an antenna as well as software for a computer chart recorder emulator (Radio Skypipe) and other reference materials

  7. Space Telecommunications Radio System STRS Cognitive Radio

    Science.gov (United States)

    Briones, Janette C.; Handler, Louis M.

    2013-01-01

    Radios today are evolving from awareness toward cognition. A software defined radio (SDR) provides the most capability for integrating autonomic decision making ability and allows the incremental evolution toward a cognitive radio. This cognitive radio technology will impact NASA space communications in areas such as spectrum utilization, interoperability, network operations, and radio resource management over a wide range of operating conditions. NASAs cognitive radio will build upon the infrastructure being developed by Space Telecommunication Radio System (STRS) SDR technology. This paper explores the feasibility of inserting cognitive capabilities in the NASA STRS architecture and the interfaces between the cognitive engine and the STRS radio. The STRS architecture defines methods that can inform the cognitive engine about the radio environment so that the cognitive engine can learn autonomously from experience, and take appropriate actions to adapt the radio operating characteristics and optimize performance.

  8. rTPPM: Towards Improving Solid-State NMR Two-Pulse Phase-Modulation Heteronuclear Dipolar Decoupling Sequence by Refocusing

    DEFF Research Database (Denmark)

    Equbal, Asif; Paul, Subhradip; Mithu, Venus Singh

    2014-01-01

    We present here a simple refocused modification, r TPPM, of the Two-Pulse Phase-Modulation (TPPM) heteronuclear decoupling method, which improves decoupling and makes the sequence much more robust with respect to essential experimental parameters. The modified sequence is compared with the establ...

  9. Time-Chunking and Hyper-Refocusing in a Digitally-Enabled Workplace: Six Forms of Knowledge Workers

    Science.gov (United States)

    Gaskin, James E.; Skousen, Tanner

    2016-01-01

    Until the turn of the millennium, switching tasks required moving locations or reconfiguring physical workspaces. However, contemporary digital tools and workspaces allow knowledge workers to perform an increasingly diverse set of tasks, with an increasingly extending arm of influence, all from the same physical location without any physical reconfigurations or traversing of physical space. Along with this increased ambidexterity comes an increase in the quantity and frequency of demands on the time of knowledge workers. This digitalization of work now tethers their ability to perform largely to their ability to intensely focus in small chunks, and then “hyper-jump” that focus to another task without traversing the cognitive cool downs or warm ups required to reconfigure their train of thought from one task to another. Accordingly, they must become more like the hyper-functioning tools they employ if they are to avoid becoming the bottleneck resource in the configuration of socio-technical elements comprising their work routines. In order to better understand how knowledge workers manage their time and maintain focus across multiple and interrupting tasks, we leverage current time prioritization literature to propose and theorize around two key constructs: time-chunking and hyper-refocusing. By combining the possible values for these two constructs, we hypothesize the emergence of six forms of knowledge workers and their relative expected performance. The effects of digitalization on these new worker forms are discussed. We conclude by discussing opportunities for new research questions regarding time-chunking strategies and the hyper-refocusing ability. PMID:27822193

  10. Supporting recovery in patients with psychosis through care by community-based adult mental health teams (REFOCUS): a multisite, cluster, randomised, controlled trial.

    Science.gov (United States)

    Slade, Mike; Bird, Victoria; Clarke, Eleanor; Le Boutillier, Clair; McCrone, Paul; Macpherson, Rob; Pesola, Francesca; Wallace, Genevieve; Williams, Julie; Leamy, Mary

    2015-06-01

    Mental health policy in many countries is oriented around recovery, but the evidence base for service-level recovery-promotion interventions is lacking. We did a cluster, randomised, controlled trial in two National Health Service Trusts in England. REFOCUS is a 1-year team-level intervention targeting staff behaviour to increase focus on values, preferences, strengths, and goals of patients with psychosis, and staff-patient relationships, through coaching and partnership. Between April, 2011, and May, 2012, community-based adult mental health teams were randomly allocated to provide usual treatment plus REFOCUS or usual treatment alone (control). Baseline and 1-year follow-up outcomes were assessed in randomly selected patients. The primary outcome was recovery and was assessed with the Questionnaire about Processes of Recovery (QPR). We also calculated overall service costs. We used multiple imputation to estimate missing data, and the imputation model captured clustering at the team level. Analysis was by intention to treat. This trial is registered, number ISRCTN02507940. 14 teams were included in the REFOCUS group and 13 in the control group. Outcomes were assessed in 403 patients (88% of the target sample) at baseline and in 297 at 1 year. Mean QPR total scores did not differ between the two groups (REFOCUS group 40·6 [SD 10·1] vs control 40·0 [10·2], adjusted difference 0·68, 95% CI -1·7 to 3·1, p=0·58). High team participation was associated with higher staff-rated scores for recovery-promotion behaviour change (adjusted difference -0·4, 95% CI -0·7 to -0·2, p=0·001) and patient-rated QPR interpersonal scores (-1·6, -2·7 to -0·5, p=0·005) at follow-up than low participation. Patients treated in the REFOCUS group incurred £1062 (95% CI -1103 to 3017) lower adjusted costs than those in the control group. Although the primary endpoint was negative, supporting recovery might, from the staff perspective, improve functioning and reduce needs

  11. REFOCUS Trial: protocol for a cluster randomised controlled trial of a pro-recovery intervention within community based mental health teams

    Directory of Open Access Journals (Sweden)

    Slade Mike

    2011-11-01

    Full Text Available Abstract Background There is a consensus about the importance of 'recovery' in mental health services, but the evidence base is limited. Methods/Design A two centre, cluster randomised controlled trial. Participants are community-based mental health teams, and service users aged 18-65 years with a primary clinical diagnosis of psychosis. In relation to the REFOCUS Manual researchintorecovery.com/refocus, which describes a 12-month, pro-recovery intervention based on the REFOCUS Model, the objectives are: (1 To establish the effectiveness of the intervention described in the REFOCUS Manual; (2 To validate the REFOCUS Model; (3 To establish and optimise trial parameters for the REFOCUS Manual; and (4 To understand the relationship between clinical outcomes and recovery outcomes. The hypothesis for the main study is that service users in the intervention arm will experience significantly greater increases in measures of personal recovery (as measured by the QPR compared to service users receiving care from control teams. The hypothesis for the secondary study is that black service users in the intervention arm will experience significantly greater increases in measures of personal recovery (as measured by the QPR and client satisfaction (as measured by the CSQ compared to Black service users receiving care from control teams. The intervention comprises treatment as usual plus two components: recovery-promoting relationships and working practices. The control condition is treatment as usual. The primary outcme is the Process of Recovery Questionnaire (QPR. Secondary outcomes are satisfaction, Goal setting - Personal Primary Outcome, hope, well-being, empowerment, and quality of life. Primary outcomes for the secondary study will be QPR and satisfaction. Cost data will be estimated, and clinical outcomes will also be reported (symptomatology, need, social disability, functioning. 29 teams (15 intervention and 14 control will be randomised. Within

  12. An opportunity to refocus on the 'humane' in experimental endpoints: moving beyond Directive 2010/63/EU.

    Science.gov (United States)

    Ashall, Vanessa; Millar, Kate

    2013-09-01

    Humane endpoints are a core refinement concept in animal experimentation. This paper identifies an urgent requirement for individuals and institutions to refocus on humane endpoints as part of the transposition of Directive 2010/63/EU into the national laws of the Member States, and to go beyond their legal construction when setting new guidance or applying humane endpoints in practice. It will be argued that requirements for humane endpoints within the Directive appear not to promote recent advances in best practice, but seem reliant on a narrow and potentially outdated definition of the term. We describe progress that has been made in encouraging change in the construction and application of humane endpoints, and suggest that Directive 2010/63/EU does not sufficiently acknowledge the conceptual complexity of this refinement strategy. For example, a useful development representing recent consensual views of best practice has been proposed by an EU consortium (in 2012). A complex approach to humane endpoints may place additional demands on institutions and raise challenges that would, unfortunately, not need to be overcome in order to remain within the Directive's current requirements regarding humane endpoints. We argue that there is now a need for a practical tool to help structure appropriate ethical reflection during research planning and experimentation, in order to facilitate best practice in the application of this important refinement concept. 2013 FRAME.

  13. Reducing cardiovascular risk factors in non-selected outpatients with schizophrenia

    DEFF Research Database (Denmark)

    Hansen, Mette Vinther; Hjorth, Peter; Kristiansen, Christina Blanner;

    2016-01-01

    glucose, serum lipids, and information on smoking and alcohol were obtained. Results: On average, small significant increases in body mass index (BMI) and waist circumferences were observed while small non-significant improvements in other cardiovascular risk factors were seen. Patients with high baseline......Objectives: Cardiovascular diseases are the most common causes of premature death in patients with schizophrenia. We aimed at reducing cardiovascular risk factors in non-selected outpatients with schizophrenia using methods proven effective in short-term trials. Furthermore, we examined whether any...... motivated to participate in the interventions, and it was difficult to monitor the recommended metabolic risk measures in the patient group. Future research should focus on simple strategies in health promotion that can be integrated into routine care....

  14. Radio frequency detection assembly and method for detecting radio frequencies

    Science.gov (United States)

    Cown, Steven H.; Derr, Kurt Warren

    2010-03-16

    A radio frequency detection assembly is described and which includes a radio frequency detector which detects a radio frequency emission produced by a radio frequency emitter from a given location which is remote relative to the radio frequency detector; a location assembly electrically coupled with the radio frequency detector and which is operable to estimate the location of the radio frequency emitter from the radio frequency emission which has been received; and a radio frequency transmitter electrically coupled with the radio frequency detector and the location assembly, and which transmits a radio frequency signal which reports the presence of the radio frequency emitter.

  15. Impact of cognitive radio on radio astronomy

    NARCIS (Netherlands)

    Bentum, M.J.; Boonstra, A.J.; Baan, W.A.

    2010-01-01

    The introduction of new communication techniques requires an increase in the efficiency of spectrum usage. Cognitive radio is one of the new techniques that fosters spectrum efficiency by using unoccupied frequency spectrum for communications. However, cognitive radio will increase the transmission

  16. Resonance and Radio

    Science.gov (United States)

    Starrett, Malin J.

    2008-01-01

    The science and technology of radio receives little attention in contemporary education. This article discusses ways to explore the basic operating principles of radio. (Contains 4 figures, 3 footnotes, and 2 notes.)

  17. Enhancing detection sensitivity in gradient liquid chromatography via post-column refocusing and strong-solvent remobilization.

    Science.gov (United States)

    De Vos, Jelle; Desmet, Gert; Eeltink, Sebastiaan

    2016-07-15

    We developed earlier the post-column refocusing strategy for isocratic separations, which employs trapping target analytes after an analytical separation and additionally focusing them using a strong remobilization solvent prior to detection, and have now extended it to high-speed gradient LC. A gradient separation of antibiotics and its metabolites, applying a linear aqueous acetonitrile gradient from 2 to 65% (v/v) ACN containing 0.1% FA in 10min, performed on an analytical column was selected as an application. Eluted heart-cut fractions were directed from the analytical silica C18 column to a trap column packed with Hypercarb particles. The remobilization of the target analytes was performed in back-flush mode using solvent mixtures tuned to maximize the solvent strength by mixing isopropanol into the remobilization solvent containing acetonitrile. Additionally, a viscosity-calibration experiment showed that the viscosity difference between trapping and remobilization solvents should be smaller than 0.15mPa·s to prevent viscous fingering. To keep the viscosity difference below this limit, during the gradient separation performed on the analytical column, the composition of the remobilization solvent was changed in time. An empirical equation is provided that allows for the selection of the optimal remobilization-solvent composition. To maximize the signal enhancement, the loading time of target analytes on the trap column should be optimized. Peak dispersion was further minimized by applying a flow rate that corresponded to the optimal van-Deemter flow rate of the trap column (20μL/min). Finally, decreasing the diameter of the trap column from 1mm to 0.3mm led to a significant enhancement of the detection sensitivity with more than one order of magnitude. Using an optimized trap configuration and elution/remobilization conditions, a signal enhancement of a factor of 14 was achieved for sulfaguanidine (early-eluting compound in the gradient separation) and 7

  18. Educational Radio in India

    OpenAIRE

    VYAS, R. V.; R. C. Sharma; Kumar, Ashwini

    2002-01-01

    There are a good number of research studies, which indicate that radio has been a good medium of education delivery. Many experiments have been conducted in different countries on the use of radio in education. Radio has been used in conventional education, non-formal education, for agricultural education, for community development, in distance education, so on and so forth. This paper explains various educational radio projects undertaken in India

  19. Commercial Radio as Communication.

    Science.gov (United States)

    Rothenbuhler, Eric W.

    1996-01-01

    Compares the day-to-day work routines of commercial radio with the principles of a theoretical communication model. Illuminates peculiarities of the conduct of communication by commercial radio. Discusses the application of theoretical models to the evaluation of practicing institutions. Offers assessments of commercial radio deriving from…

  20. Non-selective cation channels mediate chloroquine-induced relaxation in precontracted mouse airway smooth muscle.

    Directory of Open Access Journals (Sweden)

    Ting Zhang

    Full Text Available Bitter tastants can induce relaxation in precontracted airway smooth muscle by activating big-conductance potassium channels (BKs or by inactivating voltage-dependent L-type Ca2+ channels (VDLCCs. In this study, a new pathway for bitter tastant-induced relaxation was defined and investigated. We found nifedipine-insensitive and bitter tastant chloroquine-sensitive relaxation in epithelium-denuded mouse tracheal rings (TRs precontracted with acetylcholine (ACH. In the presence of nifedipine (10 µM, ACH induced cytosolic Ca2+ elevation and cell shortening in single airway smooth muscle cells (ASMCs, and these changes were inhibited by chloroquine. In TRs, ACH triggered a transient contraction under Ca2+-free conditions, and, following a restoration of Ca2+, a strong contraction occurred, which was inhibited by chloroquine. Moreover, the ACH-activated whole-cell and single channel currents of non-selective cation channels (NSCCs were blocked by chloroquine. Pyrazole 3 (Pyr3, an inhibitor of transient receptor potential C3 (TRPC3 channels, partially inhibited ACH-induced contraction, intracellular Ca2+ elevation, and NSCC currents. These results demonstrate that NSCCs play a role in bitter tastant-induced relaxation in precontracted airway smooth muscle.

  1. Ham radio for dummies

    CERN Document Server

    Silver, H Ward

    2013-01-01

    An ideal first step for learning about ham radio Beyond operating wirelessly, today's ham radio operators can transmit data and pictures; use the Internet, laser, and microwave transmitters; and travel to places high and low to make contact. This hands-on beginner guide reflects the operational and technical changes to amateur radio over the past decade and provides you with updated licensing requirements and information, changes in digital communication (such as the Internet, social media, and GPS), and how to use e-mail via radio. Addresses the critical use of ham radio for replacing downe

  2. Radiography of Spanish Radio

    Directory of Open Access Journals (Sweden)

    Dra. Emma Rodero Antón

    2007-01-01

    Full Text Available In its eighty years of existence, radio has been always characterized to adapt to the social, cultural and technological transformations. Thus it has been until this moment. Nevertheless, some years ago, the authors and professionals of this medium have been detecting a stagnation that affects to its structure. At a time in continuous technological evolution, radio demands a deep transformation. For that reason, from the conviction of which the future radio, public and commercial, will necessarily have to renew itself, in this paper we establish ten problems and their possible solutions to the radio crisis in order to draw an x-ray of radio in Spain. Radio has future, but it is necessary to work actively by it. That the radio continues being part of sound of our life, it will depend on the work of all: companies, advertisers, professionals, students, investigators and listeners.

  3. Faster pediatric 3-T abdominal magnetic resonance imaging: comparison between conventional and variable refocusing flip-angle single-shot fast spin-echo sequences

    Energy Technology Data Exchange (ETDEWEB)

    Ruangwattanapaisarn, Nichanan [Mahidol University, Department of Diagnostic and Therapeutic Radiology, Ramathibodi Hospital, Bangkok (Thailand); Stanford University, LPCH Department of Radiology, Stanford, CA (United States); Loening, Andreas M.; Saranathan, Manojkumar; Vasanawala, Shreyas S. [Stanford University, LPCH Department of Radiology, Stanford, CA (United States); Litwiller, Daniel V. [GE Healthcare, Rochester, MN (United States)

    2015-06-15

    Single-shot fast spin echo (SSFSE) is particularly appealing in pediatric patients because of its motion robustness. However radiofrequency energy deposition at 3 tesla forces long pauses between slices, leading to longer scans, longer breath-holds and more between-slice motion. We sought to learn whether modulation of the SSFSE refocusing flip-angle train could reduce radiofrequency energy deposition without degrading image quality, thereby reducing inter-slice pauses and overall scan times. We modulated the refocusing flip-angle train for SSFSE to minimize energy deposition while minimizing blurring and motion-related signal loss. In a cohort of 50 consecutive patients (25 boys, mean age 5.5 years, range 1 month to 17 years) referred for abdominal MRI we obtained standard SSFSE and variable refocusing flip-angle (vrfSSFSE) images and recorded sequence scan times. Two readers independently scored the images in blinded, randomized order for noise, tissue contrast, sharpness, artifacts and left lobe hepatic signal uniformity on a four-point scale. The null hypothesis of no difference between SSFSE and vrfSSFSE image-quality was assessed with a Mann-Whitney U test, and the null hypothesis of no scan time difference was assessed with the paired t-test. SSFSE and vrfSSFSE mean acquisition times were 54.3 and 26.2 s, respectively (P-value <0.0001). For each reader, SSFSE and vrfSSFSE noise, tissue contrast, sharpness and artifacts were not significantly different (P-values 0.18-0.86). However, SSFSE had better left lobe hepatic signal uniformity (P < 0.01, both readers). vrfSSFSE is twice as fast as SSFSE, with equivalent image quality with the exception of left hepatic lobe signal heterogeneity. (orig.)

  4. Analisis Kendala Perizinan Spektrum Frekuensi Radio untuk Radio Komunitas

    OpenAIRE

    Sri Wahyuningsih

    2014-01-01

    Izin penggunaan spektrum frekuensi radio diatur dalam Undang-undang No.36 tahun 1999 tentang Telekomunikasi. Saat ini masih ditemukan Radio Komunitas yang belum memiliki Izin Stasiun Radio (ISR). Penelitian ini bertujuan untuk menemu kenali kendala-kendala yang dihadapi Radio Komunitas pada proses pengajuan Izin Stasiun Radio (ISR). Teknik pengumpulan data melalui wawancara dengan penanggungjawab Radio Komunitas dan pejabat di lingkungan Balai Monitor Frekuensi Radio (Balmon) di Jakarta, Sema...

  5. Analisis Kendala Perizinan Spektrum Frekuensi Radio untuk Radio Komunitas

    OpenAIRE

    2014-01-01

    Izin penggunaan spektrum frekuensi radio diatur dalam Undang-undang No.36 tahun 1999 tentang Telekomunikasi. Saat ini masih ditemukan Radio Komunitas yang belum memiliki Izin Stasiun Radio (ISR). Penelitian ini bertujuan untuk menemu kenali kendala-kendala yang dihadapi Radio Komunitas pada proses pengajuan Izin Stasiun Radio (ISR). Teknik pengumpulan data melalui wawancara dengan penanggungjawab Radio Komunitas dan pejabat di lingkungan Balai Monitor Frekuensi Radio (Balmon) di Jakarta, Sema...

  6. Spent-beam refocusing analysis and multistage depressed collector design for a 75-W, 59- to 64-GHz coupled-cavity traveling-wave tube

    Science.gov (United States)

    Wilson, Jeffrey D.; Ramins, Peter; Force, Dale A.

    1990-01-01

    A computational design technique for coupled-cavity tubes (TWTs) equipped with spent-beam refocusers (SBRs) and multistage depressed collectors (MDCs) is described. A large-signal multidimensional computer program was used to analyze the TWT-SBR performance and to generate the spent-beam models used for MDC design. The results of a design involving a 75-W, 59 to 64 GHz TWT are presented. The SBR and MDC designs are shown, and the computed TWT, SBR, and MDC performances are described. Collector efficiencies in excess of 94 percent led to projected overall TWT efficiencies in the 40-percent range.

  7. Refocusing the Arts Aesthetic.

    Science.gov (United States)

    Bennefield, Robin M.

    1999-01-01

    African-American performing and visual-arts scholars comment on the continuing struggle to bring the work of black artists into the full view of the academy's white majority. Some feel the American art culture has been too slow to accept minority expression. Dance programs appear to be increasing in diversity faster than most other arts…

  8. Genomic saturation mutagenesis and polygenic analysis identify novel yeast genes affecting ethyl acetate production, a non-selectable polygenic trait

    Directory of Open Access Journals (Sweden)

    Tom Den Abt

    2016-03-01

    Full Text Available Isolation of mutants in populations of microorganisms has been a valuable tool in experimental genetics for decades. The main disadvantage, however, is the inability of isolating mutants in non-selectable polygenic traits. Most traits of organisms, however, are non-selectable and polygenic, including industrially important properties of microorganisms. The advent of powerful technologies for polygenic analysis of complex traits has allowed simultaneous identification of multiple causative mutations among many thousands of irrelevant mutations. We now show that this also applies to haploid strains of which the genome has been loaded with induced mutations so as to affect as many non-selectable, polygenic traits as possible. We have introduced about 900 mutations into single haploid yeast strains using multiple rounds of EMS mutagenesis, while maintaining the mating capacity required for genetic mapping. We screened the strains for defects in flavor production, an important non-selectable, polygenic trait in yeast alcoholic beverage production. A haploid strain with multiple induced mutations showing reduced ethyl acetate production in semi-anaerobic fermentation, was selected and the underlying quantitative trait loci (QTLs were mapped using pooled-segregant whole-genome sequence analysis after crossing with an unrelated haploid strain. Reciprocal hemizygosity analysis and allele exchange identified PMA1 and CEM1 as causative mutant alleles and TPS1 as a causative genetic background allele. The case of CEM1 revealed that relevant mutations without observable effect in the haploid strain with multiple induced mutations (in this case due to defective mitochondria can be identified by polygenic analysis as long as the mutations have an effect in part of the segregants (in this case those that regained fully functional mitochondria. Our results show that genomic saturation mutagenesis combined with complex trait polygenic analysis could be used

  9. Senior radio listeners

    DEFF Research Database (Denmark)

    Blaakilde, Anne Leonora

    Radiobroadcasting and the hardware materialization of radio have during the 20th century changed significantly, which means that senior radio listeners have travelled along with this evolution from large, impressive radio furnitures to DAB and small, wireless, mobile devices, and from grave...... and solemn radio voices to lightharted, laughing and chatting speakers. Senior radio listerners have experienced the development and refinements of technique, content and genres. It is now expected of all media users that they are capable of crossing media, combining, juggling and jumping between various...... media platforms, not the least when listening to radio. The elder generation is no exception from this. Recently, for instance, the Danish public broadcast DR has carried out an exodus of programmes targeted for the senior segment. These programmes are removed from regular FM and sent to DAB receivers...

  10. Fast Radio Bursts

    Indian Academy of Sciences (India)

    Akshaya Rane; Duncan Lorimer

    2017-09-01

    We summarize our current state of knowledge of fast radio bursts (FRBs) which were first discovered a decade ago. Following an introduction to radio transients in general, including pulsars and rotating radio transients, we discuss the discovery of FRBs. We then discuss FRB follow-up observations in the context of repeat bursts before moving on to review propagation effects on FRB signals, FRB progenitor models and an outlook on FRBs as potential cosmological tools.

  11. A Zynq-based Cluster Cognitive Radio

    OpenAIRE

    Rooks, Kurtis M.

    2014-01-01

    Traditional hardware radios provide very rigid solutions to radio problems. Intelligent software defined radios, also known as cognitive radios, provide flexibility and agility compared to hardware radio systems. Cognitive radios are well suited for radio applications in a changing radio frequency environment, such as dynamic spectrum access. In this thesis, a cognitive radio is demonstrated where the system self reconfigures to dem...

  12. Transformations of Radio Aesthetics

    Directory of Open Access Journals (Sweden)

    Grażyna Stachyra

    2015-09-01

    Full Text Available The paper presents some remarks upon the nature of contemporary radio communications in the context of the terms “aesthetics” and “aesthetisation”. The latter, denoting a process of turning aesthetic phenomena into unaesthetic ones, becomes the dominant strategy of formatted radio. The “surface aesthetisation,” which provides mainly pleasure and entertainment, transcends the simple styling of objects or environment and appears to be a more significant strand of contemporary culture. The article shows several examples of “surface” modelling of radio programming and explains their purpose in radio communication.

  13. STEM on the radio

    Science.gov (United States)

    Showstack, Randy

    2011-10-01

    Looking for an Internet radio station focusing on programing about science, technology, engineering, and math (STEM)? The U.S. National Science Foundation (NSF) announced on 26 September the launch of Science360 Radio, which it says is the first Internet radio stream dedicated to STEM programing. Science360 includes more than 100 radio shows and podcasts that are available on the Web as well as on iPhone and Android devices. The shows originate from a variety of sources, including NSF, other U.S. government agencies, science organizations, universities, and media outlets. For more information, see http://science360.gov/files/.

  14. Enhancing GNU Radio for Hardware Accelerated Radio Design

    OpenAIRE

    Irick, Charles Robert

    2010-01-01

    As technology evolves and new methods for designing radios arise, it becomes necessary to continue the search for fast and flexible development environments. Some of these new technologies include software defined radio (SDR), Field Programmable Gate Arrays (FPGAs), and the open source project GNU Radio. Software defined radio is a concept that GNU Radio has harnessed to allow developers to quickly create flexible radio designs. In terms of hardware, the maturity of FPGAs give ...

  15. Analisis Kendala Perizinan Spektrum Frekuensi Radio untuk Radio Komunitas

    Directory of Open Access Journals (Sweden)

    Sri Wahyuningsih

    2014-03-01

    Full Text Available Izin penggunaan spektrum frekuensi radio diatur dalam Undang-undang No.36 tahun 1999 tentang Telekomunikasi. Saat ini masih ditemukan Radio Komunitas yang belum memiliki Izin Stasiun Radio (ISR. Penelitian ini bertujuan untuk menemu kenali kendala-kendala yang dihadapi Radio Komunitas pada proses pengajuan Izin Stasiun Radio (ISR. Teknik pengumpulan data melalui wawancara dengan penanggungjawab Radio Komunitas dan pejabat di lingkungan Balai Monitor Frekuensi Radio (Balmon di Jakarta, Semarang dan Yogyakarta. Analisis data mengacu pada model Matthew B Miles dan A Michael Huberman. Hasil penelitian menyatakan kendala yang dihadapi terutama pada sertifikasi perangkat Radio Komunitas.

  16. Radio Graceful Hamming Graphs

    Directory of Open Access Journals (Sweden)

    Niedzialomski Amanda

    2016-11-01

    Full Text Available For k ∈ ℤ+ and G a simple, connected graph, a k-radio labeling f : V (G → ℤ+ of G requires all pairs of distinct vertices u and v to satisfy |f(u − f(v| ≥ k + 1 − d(u, v. We consider k-radio labelings of G when k = diam(G. In this setting, f is injective; if f is also surjective onto {1, 2, . . . , |V (G|}, then f is a consecutive radio labeling. Graphs that can be labeled with such a labeling are called radio graceful. In this paper, we give two results on the existence of radio graceful Hamming graphs. The main result shows that the Cartesian product of t copies of a complete graph is radio graceful for certain t. Graphs of this form provide infinitely many examples of radio graceful graphs of arbitrary diameter. We also show that these graphs are not radio graceful for large t.

  17. Radio Emission from Exoplanets

    OpenAIRE

    George, Samuel J.; Stevens, Ian R.

    2008-01-01

    We present results from new low frequency observations of two extrasolar planetary systems (Epsilon Eridani and HD128311) taken at 150 MHz with the Giant Metrewave Radio Telescope (GMRT). We do not detect either system, but are able to place tight upper limits on their low frequency radio emission.

  18. Valuing commercial radio licences

    NARCIS (Netherlands)

    Kerste, M.; Poort, J.; van Eijk, N.

    2015-01-01

    Within the EU regulatory framework, licensees for commercial radio broadcasting may be charged a fee to ensure optimal allocation of scarce resources but not to maximize public revenues. While radio licence renewal occurs in many EU countries, an objective, model-based approach for setting licence f

  19. Radio source evolution

    CERN Document Server

    Perucho, Manel

    2015-01-01

    Baldwin (1982) wrote that "the distribution of sources in the radio luminosity, P, overall physical size, D, diagram" could be considered as "the radio astronomer's H-R diagram". However, unlike the case of stars, not only the intrinsic properties of the jets, but also those of the host galaxy and the intergalactic medium are relevant to explain the evolutionary tracks of radio radio sources. In this contribution I review the current status of our understanding of the evolution of radio sources from a theoretical and numerical perspective, using the P-D diagram as a framework. An excess of compact (linear size < 10 kpc) sources could be explained by low-power jets being decelerated within the host galaxy, as shown by recent numerical simulations. These decelerated jets could also explain the population of the radio sources that have been recently classified as FR0. I will discuss the possible tracks that radio sources may follow within this diagram, and some of the physical processes that can explain the d...

  20. Radio broadcasting via satellite

    Science.gov (United States)

    Helm, Neil R.; Pritchard, Wilbur L.

    1990-10-01

    Market areas offering potential for future narrowband broadcast satellites are examined, including international public diplomacy, government- and advertising-supported, and business-application usages. Technical issues such as frequency allocation, spacecraft types, transmission parameters, and radio receiver characteristics are outlined. Service and system requirements, advertising revenue, and business communications services are among the economic issues discussed. The institutional framework required to provide an operational radio broadcast service is studied, and new initiatives in direct broadcast audio radio systems, encompassing studies, tests, in-orbit demonstrations of, and proposals for national and international commercial broadcast services are considered.

  1. Boom Booom Net Radio

    DEFF Research Database (Denmark)

    Grimshaw, Mark Nicholas; Yong, Louisa; Dobie, Ian

    1999-01-01

    of an existing Internet radio station; Boom Booom Net Radio. Whilst necessity dictates some use of technology-related terminology, wherever possible we have endeavoured to keep such jargon to a minimum and to either explain it in the text or to provide further explanation in the appended glossary.......Internet radio is one of the growth areas of the Internet but, as this article will show, is fraught with difficulties and frustration for both the modestly-funded broadcaster (bitcaster) and the listener. The article will illustrate some of these problems by means of a short case study...

  2. Shoestring Budget Radio Astronomy

    Science.gov (United States)

    Hoot, John E.

    2017-06-01

    The commercial exploitation of microwave frequencies for cellular, WiFi, Bluetooth, HDTV, and satellite digital media transmission has brought down the cost of the components required to build an effective radio telescope to the point where, for the cost of a good eyepiece, you can construct and operate a radio telescope. This paper sets forth a family of designs for 1421 MHz telescopes. It also proposes a method by which operators of such instruments can aggregate and archive data via the Internet. With 90 or so instruments it will be possible to survey the entire radio sky for transients with a 24 hour cadence.

  3. Unlocking radio broadcasts

    DEFF Research Database (Denmark)

    Lykke, Marianne; Skov, Mette

    2012-01-01

    This poster reports the preliminary results of a user study uncovering the information seeking behaviour of humanities scholars dedicated to radio research. The study is part of an interdisciplinary research project on radio culture and auditory resources. The purpose of the study is to inform...... the design of information architecture and interaction design of a research infrastructure that will enable future radio and audio based research. Results from a questionnaire survey on humanities scholars’ research interest and information needs, preferred access points, and indexing levels are reported...

  4. Ionosphere and Radio Communication

    Indian Academy of Sciences (India)

    Saradi Bora

    2017-02-01

    The Earth's ionosphere consists of plasma produced by thephotoionization of thin upper atmospheric gases by UV raysand photons of short wavelength from the sun. The upperionosphere is used for radio communication and navigationas it reflects long, medium, as well as short radio waves. Sincesolar radiation is the main cause of the existence of ionosphere,any variation in the radiations can affect the entireradio communication system. This article attempts to brieflyintroduce the readers to the study of ionosphere in the contextof its use as a radio reflector, with particular reference toIndia.

  5. Radio y elecciones

    Directory of Open Access Journals (Sweden)

    Alma Rosa Alva de la Selva

    2000-01-01

    Full Text Available En este trabajo se analiza el comportamiento de la radio en México ante la contienda electoral de julio de 2000. Se examina el papel de la radio como espacio para la discusión política, así como el tratamiento informativo que hizo del tema. Asimismo, se analiza la posible repercusión de factores de reciente surgimiento en el panorama radiofónico para un manejo más autónomo de la información política en la radio

  6. Unlocking radio broadcasts

    DEFF Research Database (Denmark)

    Skov, Mette; Lykke, Marianne

    2012-01-01

    This poster reports the preliminary results of a user study uncovering the information seeking behaviour of humanities scholars dedicated to radio research. The study is part of an interdisciplinary research project on radio culture and auditory resources. The purpose of the study is to inform...... the design of information architecture and interaction design of a research infrastructure that will enable future radio and audio based research. Results from a questionnaire survey on humanities scholars‟ research interest and information needs, preferred access points, and indexing levels are reported...

  7. The digital sport radio.

    Directory of Open Access Journals (Sweden)

    Hilario José ROMERO BEJARANO

    2014-07-01

    Full Text Available Radio has been immersed in recent years in a phase of technological integration and business of multimedia, as well as diversification of systems and channels for broadcasting. In addition, Internet has been consolidated as the platform of digital radio that more has evolved as a result of its continued expansion. However, the merger radio-Internet must be understood as a new form of communication, and not solely as a new complementary medium. In this context, it is of great interest to analyze that transformations in the way of reception, contents, languages, programs and schedules, has brought with it for the radio that integration. To this end is taken as main reference the sports areas, a key aspect and broadly representative of the current broadcasting landscape.

  8. Music, Radio, and Mediatization

    DEFF Research Database (Denmark)

    Krogh, Mads; Michelsen, Morten

    2016-01-01

    Mediatization has become a key concept for understanding the relations between media and other cultural and social fields. Contributing to the discussions related to the concept of mediatization, this article discusses how practices of radio and music(al life) influence each other. We follow Deacon......’s and Stanyer’s advice to supplement the concept of mediatization with ‘a series of additional concepts at lower levels of abstraction’ and suggest, in this respect, the notion of heterogeneous milieus of music– radio. Hereby, we turn away from the all-encompassing perspectives related to the concept...... of mediatization where media as such seem to be ascribed agency. Instead, we consider historical accounts of music–radio in order to address the complex non- linearity of concrete processes of mediatization as they take place in the multiple meetings between a decentred notion of radio and musical life....

  9. Unveiling the radio cosmos

    Science.gov (United States)

    Vanderlinde, Keith

    2017-02-01

    Using a radio telescope with no moving parts, the dark energy speeding up the expansion of the Universe can be probed in unprecedented detail, says Keith Vanderlinde, on behalf of the CHIME collaboration.

  10. Everyday Radio Telescope

    CERN Document Server

    Mandal, Pranshu; Kumar, Pratik; Yelikar, Anjali; Soni, Kanchan; T, Vineeth Krishna

    2016-01-01

    We have developed an affordable, portable college level radio telescope for amateur radio astronomy which can be used to provide hands-on experience with the fundamentals of a radio telescope and an insight into the realm of radio astronomy. With our set-up one can measure brightness temperature and flux of the Sun at 11.2 GHz and calculate the beam width of the antenna. The set-up uses commercially available satellite television receiving system and parabolic dish antenna. We report the detection of point sources like Saturn and extended sources like the galactic arm of the Milky way. We have also developed python pipeline, which are available for free download, for data acquisition and visualization.

  11. Division x: Radio Astronomy

    Science.gov (United States)

    Taylor, Russ; Chapman, Jessica; Rendong, Nan; Carilli, Christopher; Giovannini, Gabriele; Hills, Richard; Hirabayashi, Hisashi; Jonas, Justin; Lazio, Joseph; Morganti, Raffaella; Rubio, Monica; Shastri, Prajval

    2012-04-01

    This triennium has seen a phenomenal investment in development of observational radio astronomy facilities in all parts of the globe at a scale that significantly impacts the international community. This includes both major enhancements such as the transition from the VLA to the EVLA in North America, and the development of new facilities such as LOFAR, ALMA, FAST, and Square Kilometre Array precursor telescopes in Australia and South Africa. These developments are driven by advances in radio-frequency, digital and information technologies that tremendously enhance the capabilities in radio astronomy. These new developments foreshadow major scientific advances driven by radio observations in the next triennium. We highlight these facility developments in section 3 of this report. A selection of science highlight from this triennium are summarized in section 2.

  12. Boom Booom Net Radio

    DEFF Research Database (Denmark)

    Grimshaw, Mark Nicholas; Yong, Louisa; Dobie, Ian

    1999-01-01

    Internet radio is one of the growth areas of the Internet but, as this article will show, is fraught with difficulties and frustration for both the modestly-funded broadcaster (bitcaster) and the listener. The article will illustrate some of these problems by means of a short case study of an exi......Internet radio is one of the growth areas of the Internet but, as this article will show, is fraught with difficulties and frustration for both the modestly-funded broadcaster (bitcaster) and the listener. The article will illustrate some of these problems by means of a short case study...... of an existing Internet radio station; Boom Booom Net Radio. Whilst necessity dictates some use of technology-related terminology, wherever possible we have endeavoured to keep such jargon to a minimum and to either explain it in the text or to provide further explanation in the appended glossary....

  13. Social cognitive radio networks

    CERN Document Server

    Chen, Xu

    2015-01-01

    This brief presents research results on social cognitive radio networks, a transformational and innovative networking paradigm that promotes the nexus between social interactions and cognitive radio networks. Along with a review of the research literature, the text examines the key motivation and challenges of social cognitive radio network design. Three socially inspired distributed spectrum sharing mechanisms are introduced: adaptive channel recommendation mechanism, imitation-based social spectrum sharing mechanism, and evolutionarily stable spectrum access mechanism. The brief concludes with a discussion of future research directions which ascertains that exploiting social interactions for distributed spectrum sharing will advance the state-of-the-art of cognitive radio network design, spur a new line of thinking for future wireless networks, and enable novel wireless service and applications.

  14. Smart Radio Spectrum Management for Cognitive Radio

    Directory of Open Access Journals (Sweden)

    Partha Pratim Bhattacharya

    2011-08-01

    Full Text Available Today’s wireless networks are characterized by fixed spectrum assignment policy. The limited availablespectrum and the inefficiency in the spectrum usage necessitate a new communication paradigm toexploit the existing wireless spectrum opportunistically. Cognitive radio is a paradigm for wirelesscommunication in which either a network or a wireless node changes its transmission or receptionparameters to communicate efficiently avoiding interference with licensed or unlicensed users. It cancapture best available spectrum to meet user communication requirements (spectrum management. Inthis work, a fuzzy logic based system for spectrum management is proposed where the radio can shareunused spectrum depending on parameters like distance, signal strength, node velocity and availabilityof unused spectrum. The system is simulated and is found to give satisfactory results.

  15. Wireless radio a history

    CERN Document Server

    Coe, Lewis

    2006-01-01

    ""Informative...recommended""--Choice; ""interesting...a good read...well worth reading""--Contact Magazine. This history first looks at Marconi's wireless communications system and then explores its many applications, including marine radio, cellular telephones, police and military uses, television and radar. Radio collecting is also discussed, and brief biographies are provided for the major figures in the development and use of the wireless.

  16. Randomized trial of switching from prescribed non-selective non-steroidal anti-inflammatory drugs to prescribed celecoxib

    DEFF Research Database (Denmark)

    Macdonald, Thomas M; Hawkey, Chris J; Ford, Ian;

    2016-01-01

    BACKGROUND: Selective cyclooxygenase-2 inhibitors and conventional non-selective non-steroidal anti-inflammatory drugs (nsNSAIDs) have been associated with adverse cardiovascular (CV) effects. We compared the CV safety of switching to celecoxib vs. continuing nsNSAID therapy in a European setting...... primary events per 1000 patient-years exposure. There were only 15 adjudicated secondary upper gastrointestinal complication endpoints (0.078/100 patient-years on celecoxib vs. 0.053 on nsNSAIDs OT, 0.078 vs. 0.053 ITT). More gastrointestinal serious adverse reactions and haematological adverse reactions...

  17. Classics in radio astronomy

    CERN Document Server

    Sullivan, Woodruff Turner

    1982-01-01

    Radio techniques were the nrst to lead astronomy away from the quiescent and limited Universe revealed by traditional observations at optical wave­ lengths. In the earliest days of radio astronomy, a handful of radio physicists and engineers made one startling discovery after another as they opened up the radio sky. With this collection of classic papers and the extensive intro­ ductory material, the reader can experience these exciting discoveries, as well as understand the developing techniques and follow the motivations which prompted the various lines of inquiry. For instance he or she will follow in detail the several attempts to detect radio waves from the sun at the turn of the century; the unravelling by Jansky of a "steady hiss type static"; the incredible story of Reber who built a 9 meter dish in his backyard in 1937 and then mapped the Milky Way; the vital discoveries by Hey and colleagues of radio bursts from the Sun and of a discrete source in the constellation of Cygnus; the development of re...

  18. Capillary electrophoresis for the characterization of quantum dots after non-selective or selective bioconjugation with antibodies for immunoassay

    Directory of Open Access Journals (Sweden)

    Lai Edward PC

    2008-10-01

    Full Text Available Abstract Capillary electrophoresis coupled with laser-induced fluorescence was used for the characterization of quantum dots and their conjugates to biological molecules. The CE-LIF was laboratory-built and capable of injection (hydrodynamic and electrokinetic from sample volumes as low as 4 μL via the use of a modified micro-fluidic chip platform. Commercially available quantum dots were bioconjugated to proteins and immunoglobulins through the use of established techniques (non-selective and selective. Non-selective techniques involved the use of EDCHCl/sulfo-NHS for the conjugation of BSA and myoglobin to carboxylic acid-functionalized quantum dots. Selective techniques involved 1 the use of heterobifunctional crosslinker, sulfo-SMCC, for the conjugation of partially reduced IgG to amine-functionalized quantum dots, and 2 the conjugation of periodate-oxidized IgGs to hydrazide-functionalized quantum dots. The migration times of these conjugates were determined in comparison to their non-conjugated QD relatives based upon their charge-to-size ratio values. The performance of capillary electrophoresis in characterizing immunoconjugates of quantum dot-labeled IgGs was also evaluated. Together, both QDs and CE-LIF can be applied as a sensitive technique for the detection of biological molecules. This work will contribute to the advancements in applying nanotechnology for molecular diagnosis in medical field.

  19. Tools of radio astronomy

    CERN Document Server

    Wilson, Thomas L; Hüttemeister, Susanne

    2013-01-01

    This 6th edition of “Tools of Radio Astronomy”, the most used introductory text in radio astronomy, has been revised to reflect the current state of this important branch of astronomy. This includes the use of satellites, low radio frequencies, the millimeter/sub-mm universe, the Cosmic Microwave Background and the increased importance of mm/sub-mm dust emission. Several derivations and presentations of technical aspects of radio astronomy and receivers, such as receiver noise, the Hertz dipole and  beam forming have been updated, expanded, re-worked or complemented by alternative derivations. These reflect advances in technology. The wider bandwidths of the Jansky-VLA and long wave arrays such as LOFAR and mm/sub-mm arrays such as ALMA required an expansion of the discussion of interferometers and aperture synthesis. Developments in data reduction algorithms have been included. As a result of the large amount of data collected in the past 20 years, the discussion of solar system radio astronomy, dust em...

  20. Radio data archiving system

    Science.gov (United States)

    Knapic, C.; Zanichelli, A.; Dovgan, E.; Nanni, M.; Stagni, M.; Righini, S.; Sponza, M.; Bedosti, F.; Orlati, A.; Smareglia, R.

    2016-07-01

    Radio Astronomical Data models are becoming very complex since the huge possible range of instrumental configurations available with the modern Radio Telescopes. What in the past was the last frontiers of data formats in terms of efficiency and flexibility is now evolving with new strategies and methodologies enabling the persistence of a very complex, hierarchical and multi-purpose information. Such an evolution of data models and data formats require new data archiving techniques in order to guarantee data preservation following the directives of Open Archival Information System and the International Virtual Observatory Alliance for data sharing and publication. Currently, various formats (FITS, MBFITS, VLBI's XML description files and ancillary files) of data acquired with the Medicina and Noto Radio Telescopes can be stored and handled by a common Radio Archive, that is planned to be released to the (inter)national community by the end of 2016. This state-of-the-art archiving system for radio astronomical data aims at delegating as much as possible to the software setting how and where the descriptors (metadata) are saved, while the users perform user-friendly queries translated by the web interface into complex interrogations on the database to retrieve data. In such a way, the Archive is ready to be Virtual Observatory compliant and as much as possible user-friendly.

  1. Galactic radio astronomy

    CERN Document Server

    Sofue, Yoshiaki

    2017-01-01

    This book is a concise primer on galactic radio astronomy for undergraduate and graduate students, and provides wide coverage of galactic astronomy and astrophysics such as the physics of interstellar matter and the dynamics and structure of the Milky Way Galaxy and galaxies. Radio astronomy and its technological development have led to significant progress in galactic astronomy and contributed to understanding interstellar matter and galactic structures. The book begins with the fundamental physics of radio-wave radiation, i.e., black body radiation, thermal emission, synchrotron radiation, and HI and molecular line emissions. The author then gives overviews of ingredients of galactic physics, including interstellar matter such as the neutral (HI), molecular hydrogen, and ionized gases, as well as magnetic fields in galaxies. In addition, more advanced topics relevant to the Galaxy and galaxies are also contained here: star formation, supernova remnants, the Galactic Center and black holes, galactic dynamics...

  2. ANTENNA OF RADIO CONTROL

    Directory of Open Access Journals (Sweden)

    Ludwig Ilnytskyi

    2015-12-01

    Full Text Available The article is devoted to current issues in the field of radio monitoring. In this article was considered the antenna of radio control, which represents a grid from three vibrators. Threelement antenna array provides simultaneous control of two radio electronic devices that radiates at frequencies that are close to each other. Antenna system using simple technical means provides noise suppression, even if noise will have the same frequency as useful signal. This makes it possible to use the antenna system in conditions of multibeam wave propagation under the adjustment on the most intense by the power beam. Antenna system makes it possible to measure the electromagnetic field intensity, congestion of the frequency spectrum, direction of noise electromagnetic waves incidence, noise electric field intensity.

  3. Comets at radio wavelengths

    CERN Document Server

    Crovisier, Jacques; Colom, Pierre; Biver, Nicolas

    2016-01-01

    Comets are considered as the most primitive objects in the Solar System. Their composition provides information on the composition of the primitive solar nebula, 4.6 Gyr ago. The radio domain is a privileged tool to study the composition of cometary ices. Observations of the OH radical at 18 cm wavelength allow us to measure the water production rate. A wealth of molecules (and some of their isotopologues) coming from the sublimation of ices in the nucleus have been identified by observations in the millimetre and submillimetre domains. We present an historical review on radio observations of comets, focusing on the results from our group, and including recent observations with the Nan\\c{c}ay radio telescope, the IRAM antennas, the Odin satellite, the Herschel space observatory, ALMA, and the MIRO instrument aboard the Rosetta space probe.

  4. Mobile radio channels

    CERN Document Server

    Pätzold, Matthias

    2011-01-01

    Providing a comprehensive overview of the modelling, analysis and simulation of mobile radio channels, this book gives a detailed understanding of fundamental issues and examines state-of-the-art techniques in mobile radio channel modelling. It analyses several mobile fading channels, including terrestrial and satellite flat-fading channels, various types of wideband channels and advanced MIMO channels, providing a fundamental understanding of the issues currently being investigated in the field. Important classes of narrowband, wideband, and space-time wireless channels are explored in deta

  5. Saber sobre la radio

    OpenAIRE

    Mata, María Cristina; Universidad Nacional de Córdoba. Argentina

    1998-01-01

    La autora propone en este artículo repensar los fundamentos sobre los cuales se estructuran las asignaturas y talleres de radio en las escuelas de Comunicación Social en Latinoamérica, con el proposito de romper la escisión  entre teoría/práctica y de no violentar su complejidad: en la radio, entendida como práctica comunicativa, se juega en primer lugar una "red de vinculaciones e intercambios" en condiciones privilegiadas para la dialoguicidad. En un segundo lugar, asociado al desarrollo de...

  6. Pyrrolo- and pyridomorphinans: non-selective opioid antagonists and delta opioid agonists/mu opioid partial agonists.

    Science.gov (United States)

    Kumar, V; Clark, M J; Traynor, J R; Lewis, J W; Husbands, S M

    2014-08-01

    Opioid ligands have found use in a number of therapeutic areas, including for the treatment of pain and opiate addiction (using agonists) and alcohol addiction (using antagonists such as naltrexone and nalmefene). The reaction of imines, derived from the opioid ligands oxymorphone and naltrexone, with Michael acceptors leads to pyridomorphinans with structures similar to known pyrrolo- and indolomorphinans. One of the synthesized compounds, 5e, derived from oxymorphone had substantial agonist activity at delta opioid receptors but not at mu and/or kappa opioid receptors and in that sense profiled as a selective delta opioid receptor agonist. The pyridomorphinans derived from naltrexone and naloxone were all found to be non-selective potent antagonists and as such could have utility as treatments for alcohol abuse.

  7. Effects of the non-selective phosphodiesterase inhibitor pentoxifylline on regional cerebral blood flow and large arteries in healthy subjects

    DEFF Research Database (Denmark)

    Kruuse, Christina; Jacobsen, T B; Thomsen, Lars Lykke

    2000-01-01

    -inhalation SPECT. High-frequency ultrasound was used for measurements of temporal and radial artery diameter. Cyclic guanosine monophosphate (cGMP) and cyclic adenosine monophosphate (cAMP) concentrations were assessed in plasma. Except for increased heart rate (P blood pressure (P ... or to other mechanisms is not clear. In the present double-blind crossover study, 10 healthy subjects received pentoxifylline 300 mg or placebo intravenously on separate days. Blood flow velocity in the middle cerebral artery (V(mca)) was recorded by transcranial Doppler and rCBF was measured using (133)Xenon......The vasodilating properties of the non-selective phosphodiesterase (PDE) inhibitor pentoxifylline were evaluated. Pentoxifylline has been reported to increase cerebral blood flow (CBF) and improve recovery rate of stroke patients. Whether these results are due to a dilating effect on arteries...

  8. Non-selective beta-adrenergic blockade prevents reduction of the cerebral metabolic ratio during exhaustive exercise in humans

    DEFF Research Database (Denmark)

    Larsen, T.S.; Rasmussen, P.; Overgaard, M.

    2008-01-01

    of a non-selective beta-adrenergic (beta(1) + beta(2)) receptor antagonist (propranolol) reduced heart rate (69 +/- 8 to 58 +/- 6 beats min(-1)) and exercise capacity (239 +/- 42 to 209 +/- 31 W; P exercise with propranolol, the increase in a......Intense exercise decreases the cerebral metabolic ratio of oxygen to carbohydrates [O(2)/(glucose + (1/2)lactate)], but whether this ratio is influenced by adrenergic stimulation is not known. In eight males, incremental cycle ergometry increased arterial lactate to 15.3 +/- 4.2 mm (mean +/- s.......d.) and the arterial-jugular venous (a-v) difference from -0.02 +/- 0.03 mm at rest to 1.0 +/- 0.5 mm (P increased from 0.7 +/- 0.3 to 0.9 +/- 0.1 mm (P

  9. e-POP Radio Science Using Amateur Radio Transmissions

    Science.gov (United States)

    Frissell, N. A.; Perry, G. W.; Miller, E. S.; Shovkoplyas, A.; Moses, M. L.; James, H. G.; Yau, A. W.

    2015-12-01

    A major component of the enhanced Polar Outflow Probe (e-POP) Radio Receiver Instrument (RRI) mission is to utilize artificially generated radio emissions to study High Frequency (HF) radio wave propagation in the ionosphere. In the North American and European sectors, communications between amateur radio operators are a persistent and abundant source source of HF transmissions. We present the results of HF radio wave propagation experiments using amateur radio transmissions as an HF source for e-POP RRI. We detail how a distributed and autonomously operated amateur radio network can be leveraged to study HF radio wave propagation as well as the structuring and dynamics of the ionosphere over a large geographic region. In one case, the sudden disappearance of nearly two-dozen amateur radio HF sources located in the midwestern United States was used to detect a enhancement in foF2 in that same region. We compare our results to those from other more conventional radio instruments and models of the ionosphere to demonstrate the scientific merit of incorporating amateur radio networks for radio science at HF.

  10. A reconfigurable radio architecture for Cognitive Radio in emergency networks

    NARCIS (Netherlands)

    Zhang, Q.; Kokkeler, Andre B.J.; Smit, Gerardus Johannes Maria

    2006-01-01

    Cognitive Radio has been proposed as a promising technology to solve today’s spectrum scarcity problem. Cognitive Radio is able to sense the spectrum to find the free spectrum, which can be optimally used by Cognitive Radio without causing interference to the licensed user. In the scope of the

  11. A reconfigurable radio architecture for Cognitive Radio in emergency networks

    NARCIS (Netherlands)

    Zhang, Q.; Kokkeler, Andre B.J.; Smit, Gerardus Johannes Maria

    2006-01-01

    Cognitive Radio has been proposed as a promising technology to solve today’s spectrum scarcity problem. Cognitive Radio is able to sense the spectrum to find the free spectrum, which can be optimally used by Cognitive Radio without causing interference to the licensed user. In the scope of the Adapt

  12. A Reconfigurable Radio Architecture for Cognitive Radio in Emergency Networks

    NARCIS (Netherlands)

    Zhang, Qiwei; Kokkeler, Andre B.J.; Smit, Gerard J.M.

    2006-01-01

    Cognitive Radio has been proposed as a promising technology to solve today's spectrum scarcity problem. Cognitive Radio is able to sense the spectrum to find the free spectrum, which can be optimally used by Cognitive Radio without causing interference to the licensed user. In the scope of the Adapt

  13. Spectrum management and radio resource management considering cognitive radio systems

    NARCIS (Netherlands)

    Haartsen, Jaap C.; Wieweg, Lasse; Huschke, Jörg

    2005-01-01

    International fora and some national administrations define a cognitive radio (CR) as a pioneering radio communication system that would be capable of altering and adapting its transmitter and receiver parameters based on communication and the exchange of information with related detectable radio co

  14. Radio Fatwa : Islamic Tanya-Jawab Programmes on Radio Dakwah

    NARCIS (Netherlands)

    Sunarwoto,

    2012-01-01

    The present article is a study of radio fatwa in Indonesia with special reference to the Tanya-Jawab genres in radio dakwah.The concept of fatwa has changed over time. Such Islamic Tanya-Jawab programmes broadcast on radio dakwah are important to understand how fatwa is disseminated by means of medi

  15. The LOFAR radio environment

    CERN Document Server

    Offringa, A R; Zaroubi, S; van Diepen, G; Martinez-Ruby, O; Labropoulos, P; Brentjens, M A; Ciardi, B; Daiboo, S; Harker, G; Jelic, V; Kazemi, S; Koopmans, L V E; Mellema, G; Pandey, V N; Pizzo, R F; Schaye, J; Vedantham, H; Veligatla, V; Wijnholds, S J; Yatawatta, S; Zarka, P; Alexov, A; Anderson, J; Asgekar, A; Avruch, M; Beck, R; Bell, M; Bell, M R; Bentum, M; Bernardi, G; Best, P; Birzan, L; Bonafede, A; Breitling, F; Broderick, J W; Bruggen, M; Butcher, H; Conway, J; de Vos, M; Dettmar, R J; Eisloeffel, J; Falcke, H; Fender, R; Frieswijk, W; Gerbers, M; Griessmeier, J M; Gunst, A W; Hassall, T E; Heald, G; Hessels, J; Hoeft, M; Horneffer, A; Karastergiou, A; Kondratiev, V; Koopman, Y; Kuniyoshi, M; Kuper, G; Maat, P; Mann, G; McKean, J; Meulman, H; Mevius, M; Mol, J D; Nijboer, R; Noordam, J; Norden, M; Paas, H; Pandey, M; Pizzo, R; Polatidis, A; Rafferty, D; Rawlings, S; Reich, W; Rottgering, H J A; Schoenmakers, A P; Sluman, J; Smirnov, O; Sobey, C; Stappers, B; Steinmetz, M; Swinbank, J; Tagger, M; Tang, Y; Tasse, C; van Ardenne, A; van Cappellen, W; van Duin, A P; van Haarlem, M; van Leeuwen, J; van Weeren, R J; Vermeulen, R; Vocks, C; Wijers, R A M J; Wise, M; Wucknitz, O

    2012-01-01

    Aims: This paper discusses the spectral occupancy for performing radio astronomy with the Low-Frequency Array (LOFAR), with a focus on imaging observations. Methods: We have analysed the radio-frequency interference (RFI) situation in two 24-h surveys with Dutch LOFAR stations, covering 30-78 MHz with low-band antennas and 115-163 MHz with high-band antennas. This is a subset of the full frequency range of LOFAR. The surveys have been observed with a 0.76 kHz / 1 s resolution. Results: We measured the RFI occupancy in the low and high frequency sets to be 1.8% and 3.2% respectively. These values are found to be representative values for the LOFAR radio environment. Between day and night, there is no significant difference in the radio environment. We find that lowering the current observational time and frequency resolutions of LOFAR results in a slight loss of flagging accuracy. At LOFAR's nominal resolution of 0.76 kHz and 1 s, the false-positives rate is about 0.5%. This rate increases approximately linear...

  16. Division x: Radio Astronomy

    NARCIS (Netherlands)

    Taylor, Russ; Chapman, Jessica; Rendong, Nan; Carilli, Christopher; Giovannini, Gabriele; Hills, Richard; Hirabayashi, Hisashi; Jonas, Justin; Lazio, Joseph; Morganti, Raffaella; Rubio, Monica; Shastri, Prajval

    This triennium has seen a phenomenal investment in development of observational radio astronomy facilities in all parts of the globe at a scale that significantly impacts the international community. This includes both major enhancements such as the transition from the VLA to the EVLA in North

  17. Educational Broadcasting--Radio.

    Science.gov (United States)

    Ahamed, Uvais; Grimmett, George

    This manual is intended for those who must conduct educational radio broadcasting training courses in Asia-Pacific countries without the resources of experienced personnel, as well as for individuals to use in self-learning situations. The selection of material has been influenced by the need to use broadcasting resources effectively in programs…

  18. Albanian: Basic Radio Communications.

    Science.gov (United States)

    Defense Language Inst., Washington, DC.

    This volume has been designed as a supplement to a course in Albanian developed by the Defense Language Institute. The emphasis in this text is placed on radio communications instruction. The volume is divided into five exercises, each of which contains a vocabulary, dictation, and an air-to-ground communications procedure conducted in Albanian…

  19. Valuing commercial radio licences

    NARCIS (Netherlands)

    Kerste, M.; Poort, J.; van Eijk, N.

    2011-01-01

    Within the EU Regulatory Framework, licensees for commercial radio broadcasting may be charged a fee to ensure optimal allocation of scarce resources but not to maximize public revenues. In this paper, it is described how such a fee can be determined for the purpose of licence renewal or extension.

  20. Zelenchukskaya Radio Astronomical Observatory

    Science.gov (United States)

    Smolentsev, Sergey; Dyakov, Andrei

    2013-01-01

    This report summarizes information about Zelenchukskaya Radio Astronomical Observatory activities in 2012. Last year a number of changes took place in the observatory to improve some technical characteristics and to upgrade some units to the required status. The report provides an overview of current geodetic VLBI activities and gives an outlook for the future.

  1. Svetloe Radio Astronomical Observatory

    Science.gov (United States)

    Smolentsev, Sergey; Rahimov, Ismail

    2013-01-01

    This report summarizes information about the Svetloe Radio Astronomical Observatory activities in 2012. Last year, a number of changes took place in the observatory to improve some technical characteristics and to upgrade some units to their required status. The report provides an overview of current geodetic VLBI activities and gives an outlook for the future.

  2. Dust tori in radio galaxies

    NARCIS (Netherlands)

    van der Wolk, G.; Barthel, P. D.; Peletier, R. F.; Pel, J. W.

    2010-01-01

    Aims: We investigate the quasar - radio galaxy unification scenario and detect dust tori within radio galaxies of various types. Methods: Using VISIR on the VLT, we acquired sub-arcsecond (~0.40 arcsec) resolution N-band images, at a wavelength of 11.85 μm, of the nuclei of a sample of 27 radio gala

  3. Extragalactic radio continuum surveys and the transformation of radio astronomy

    Science.gov (United States)

    Norris, Ray P.

    2017-10-01

    Next-generation radio surveys are about to transform radio astronomy by discovering and studying tens of millions of previously unknown radio sources. These surveys will provide fresh insights for understanding the evolution of galaxies, measuring the evolution of the cosmic star-formation rate, and rivalling traditional techniques in the measurement of fundamental cosmological parameters. By observing a new volume of observational parameter space, they are also likely to discover unexpected phenomena. This Review traces the evolution of extragalactic radio continuum surveys from the earliest days of radio astronomy to the present, and identifies the challenges that must be overcome to achieve this transformational change.

  4. INOVASI RADIO KAMPUS (RANCANG BANGUN RADIO UDINUS DENGAN INOVASI TEKNOLOGI @RADIO

    Directory of Open Access Journals (Sweden)

    Wellia Shinta Sari

    2014-08-01

    Full Text Available Perkembangan Teknologi Informasi dan Komunikasi (TIK memaksa industri penyiaran untuk ikut menyesuaikan diri. Radio konvensional bisa jadi akan tertinggal jika tidak melakukan inovasi teknologi yang ada. Begitu juga dengan radio kampus, yang keberadaannya sangat dibutuhkan sebagai wadah kreativitas dan sarana pembelajaran di sebuah universitas, apalagi yang memiliki program studi penyiaran. Radio kampus Suara Dian yang masih konvensional sehingga hampir kehilangan eksistensinya harus segera dibenahi dan dihidupkan kembali dengan mengikuti perkembangan teknologi di era konvergensi. Metode Inovasi teknologi yang bisa dilakukan adalah dengan menggunakan teknologi @Radio Streaming, yang bukan sekedar streaming, tapi juga optimalisasi teknologi yang terintegrasi dinamis melalui RISE (Radio Broadcasting Integrated System. Dengan berbagai fitur unggul dari inovasi teknologi tersebut, maka diharapkan Radio kampus Udinus ”Suara Dian” dapat kembali hidup, berkembang dan lebih kompetitif ditengah industri penyiaran Radio. Kata kunci : radio, kampus, konvergensi, streaming.

  5. The importance of Radio Quiet Zone (RQZ) for radio astronomy

    Science.gov (United States)

    Umar, Roslan; Abidin, Zamri Zainal; Ibrahim, Zainol Abidin

    2013-05-01

    Most of radio observatories are located in isolated areas. Since radio sources from the universe is very weak, astronomer need to avoid radio frequency interference (RFI) from active spectrum users and radio noise produced by human made (telecommunication, mobile phone, microwave user and many more. There are many observatories around the world are surrounded by a Radio Quiet Zone (RQZ), which is it was set up using public or state laws. A Radio Quiet Zone normally consists of two areas: an exclusive area in which totally radio emissions are forbidden, with restrictions for residents and business developments, and a larger (radius up to 100 km above) coordination area where the power of radio transmission limits to threshold levels. Geographical Information System (GIS) can be used as a powerful tool in mapping large areas with varying RQZ profiles. In this paper, we report the initial testing of the usage of this system in order to identify the areas were suitable for Radio Quiet Zone. Among the important parameters used to develop the database for our GIS are population density, information on TV and telecommunication (mobile phones) transmitters, road networks (highway), and contour shielding. We will also use other information gathered from on-site RFI level measurements on selected 'best' areas generated by the GIS. The intention is to find the best site for the purpose of establishing first radio quiet zones for radio telescope in Malaysia.

  6. The mouse defense test battery: evaluation of the effects of non-selective and BZ-1 (omega1) selective, benzodiazepine receptor ligands.

    Science.gov (United States)

    Griebel, G.; Sanger, D.J.; Perrault, G.

    1996-11-01

    The behavioral effects of several benzodiazepine (BZ) (omega) receptor ligands were compared using the Mouse Defense Test Battery which has been designed to assess defensive reactions of Swiss mice confronted with a natural threat (a rat) and situations associated with this threat. Primary measures taken before, during and after rat confrontation were escape attempts, flight, risk assessment and defensive threat and attack. The drugs used included non-selective BZ (omega) full (clonazepam, clorazepate, chlordiazepoxide and diazepam) and partial (bretazenil and imidazenil) agonists, and BZ-1 (omega1) selective (abecarnil, CL 218,872 and zolpidem) receptor ligands. With the exception of clonazepam, non-selective BZ (omega) receptor compounds only partially affected flight behaviors. The drugs reduced some but not all flight measures in response to the approaching rat, whereas clonazepam attenuated all flight reactions. In contrast to their mild and inconsistent actions on flight, the non-selective BZ (omega) receptor agonists displayed clear effects on risk assessment when subjects were chased by the rat. When contact was forced between the subject and the rat, the non-selective BZ (omega) receptor full agonists reduced defensive threat and attack reactions, while the partial agonists imidazenil and bretazenil only weakly attenuated defensive attack behavior. Similarly, after the rat had been removed from the test area, the non-selective BZ (omega) receptor full agonists displayed greater efficacy than the partial agonists in reducing escape attempts. Overall, results obtained with the selective BZ-1 (omega1) receptor ligands demonstrated either no clear effects or no specific action on defensive reactions. Taken together, these data demonstrate that: (1) non-selective BZ (omega) agonists displaying high intrinsic activity affect a wider range of defensive behaviors than non-selective BZ (omega) receptor partial agonists; (2) the defense system does not involve

  7. Early Recovery of Salmonella from Food Using a 6-Hour Non-selective Pre-enrichment and Reformulation of Tetrathionate Broth

    Science.gov (United States)

    Daquigan, Ninalynn; Grim, Christopher J.; White, James R.; Hanes, Darcy E.; Jarvis, Karen G.

    2016-01-01

    Culture based methods are commonly employed to detect pathogens in food and environmental samples. These methods are time consuming and complex, requiring multiple non-selective and selective enrichment broths, and usually take at least 1 week to recover and identify pathogens. Improving pathogen detection in foods is a primary goal for regulatory agencies and industry. Salmonella detection in food relies on a series of culture steps in broth formulations optimized to resuscitate Salmonella and reduce the abundance of competitive bacteria. Examples of non-selective pre-enrichment broths used to isolate Salmonella from food include Lactose, Universal Pre-enrichment, BPW, and Trypticase Soy broths. Tetrathionate (TT) and Rappaport–Vassiliadis (RV) broths are employed after a 24-h non-selective enrichment to select for Salmonella and hamper the growth of competitive bacteria. In this study, we tested a new formulation of TT broth that lacks brilliant green dye and has lower levels of TT . We employed this TT broth formulation in conjunction with a 6-h non-selective pre-enrichment period and determined that Salmonella recovery was possible one day earlier than standard food culture methods. We tested the shortened culture method in different non-selective enrichment broths, enumerated Salmonella in the non-selective enrichments, and used 16S rRNA gene sequencing to determine the proportional abundances of Salmonella in the TT and RV selective enrichments. Together these data revealed that a 6-h non-selective pre-enrichment reduces the levels of competitive bacteria inoculated into the selective TT and RV broths, enabling the recovery of Salmonella 1 day earlier than standard culture enrichment methods. PMID:28082968

  8. Thermal and Nonthermal Radio Galaxies

    CERN Document Server

    Antonucci, Robert

    2011-01-01

    Radio galaxies were discovered and mapped in the 1950s. The optical spectra showed little or no nuclear continuum light. Some also revealed powerful high ionization emission lines, while others showed at most weak low-ionization emission lines. Quasars were found in the 1960s, and their spectra were dominated by powerful continuum radiation which was subsequently identified with optically thick thermal radiation from copious accretion flows, as well as high ionization narrow emission lines, and powerful broad permitted lines. By the 1980s, data from optical polarization and statistics of the radio properties required that many radio galaxies contain hidden quasar nuclei, hidden from the line of sight by dusty, roughly toroidal gas distributions. The radio galaxies with hidden quasars are referred to as "thermal." Do all radio galaxies have powerful hidden quasars? We now know the answer using arguments based on radio, infrared, optical and X-ray properties. Near the top of the radio luminosity function, for F...

  9. THE AUGER ENGINEERING RADIO ARRAY

    Directory of Open Access Journals (Sweden)

    Klaus Weidenhaupt

    2013-12-01

    Full Text Available The Auger Engineering Radio Array currently measures MHz radio emission from extensive air showers induced by high energy cosmic rays with 24 self-triggered radio detector stations. Its unique site, embedded into the baseline detectors and extensions of the Pierre Auger Observatory, allows to study air showers in great detail and to calibrate the radio emission. In its final stage AERA will expand to an area of approximately 20km2 to explore the feasibility of the radio-detection technique for future cosmic-ray detectors. The concept and hardware design of AERA as well as strategies to enable self-triggered radio detection are presented. Radio emission mechanisms are discussed based on polarization analysis of the first AERA data.

  10. Radio observations of Planck clusters

    CERN Document Server

    Kale, Ruta

    2012-01-01

    Recently, a number of new galaxy clusters have been detected by the ESA-Planck satellite, the South Pole Telescope and the Atacama Cosmology Telescope using the Sunyaev-Zeldovich effect. Several of the newly detected clusters are massive, merging systems with disturbed morphology in the X-ray surface brightness. Diffuse radio sources in clusters, called giant radio halos and relics, are direct probes of cosmic rays and magnetic fields in the intra-cluster medium. These radio sources are found to occur mainly in massive merging clusters. Thus, the new SZ-discovered clusters are good candidates to search for new radio halos and relics. We have initiated radio observations of the clusters detected by Planck with the Giant Metrewave Radio Telescope. These observations have already led to the detection of a radio halo in PLCKG171.9-40.7, the first giant halo discovered in one of the new Planck clusters.

  11. The effect of external divalent cations on spontaneous non-selective cation channel currents in rabbit portal vein myocytes.

    Science.gov (United States)

    Albert, A P; Large, W A

    2001-10-15

    1. The effects of external divalent cations on spontaneous single non-selective cation channel currents were studied in outside-out patches from rabbit portal vein smooth muscle cells in K+-free conditions. 2. In an external medium containing 1.5 mM Ca2+ (Ca2+o) the majority of spontaneous channel currents had a unitary conductance of 23 pS, reversal potential (Vr) of +10 mV and a low open probability (Po) at negative patch potentials. Some channels opened to a lower conductance state of about 13 pS suggesting that the cation channels have two conductance states. Open time and burst duration distributions could both be described by two exponentials with time constants of about of 1 ms and 7 ms for open times and 3 ms and 16 ms for burst durations. 3. In 0 Ca2+o the majority of spontaneous cation channels had a unitary conductance of 13 pS and Vr was shifted to +4 mV. Moreover the longer open time and longer burst duration time constants were both reduced to approximately half the values in 1.5 mM Ca2+o. 4. Compared to 0 Ca2+o the single channel currents in 3 microM and 100 microM Ca2+o had a 5- to 6-fold increase in Po which was accompanied by increases in both open times and burst durations. In 3 microM and 100 microM Ca2+o the unitary conductance of the single channel currents was between 22 and 26 pS. 5. At positive membrane potentials the single channel currents had an increased Po compared to negative potentials which was associated with increased open times and burst durations but these values were similar in 3 microM, 100 microM and 1.5 mM Ca2+o. 6. In 1.5 mM Sr2+o and 1.5 mM Ba2+o channels opened to the higher conductance state of about 22-25 pS and had a 3- to 7-fold greater Po than in 0 Ca2+o. 7. In conclusion, external divalent cations have marked effects on the unitary conductance and kinetic behaviour of non-selective cation channels in rabbit portal vein smooth muscle cells.

  12. Distributed Radio Interferometric Calibration

    CERN Document Server

    Yatawatta, Sarod

    2015-01-01

    Increasing data volumes delivered by a new generation of radio interferometers require computationally efficient and robust calibration algorithms. In this paper, we propose distributed calibration as a way of improving both computational cost as well as robustness in calibration. We exploit the data parallelism across frequency that is inherent in radio astronomical observations that are recorded as multiple channels at different frequencies. Moreover, we also exploit the smoothness of the variation of calibration parameters across frequency. Data parallelism enables us to distribute the computing load across a network of compute agents. Smoothness in frequency enables us reformulate calibration as a consensus optimization problem. With this formulation, we enable flow of information between compute agents calibrating data at different frequencies, without actually passing the data, and thereby improving robustness. We present simulation results to show the feasibility as well as the advantages of distribute...

  13. Tools of radio astronomy

    CERN Document Server

    Wilson, Thomas L; Hüttemeister, Susanne

    2009-01-01

    The recent years have seen breathtaking progress in technology, especially in the receiver and digital technologies relevant for radio astronomy, which has at the same time advanced to shorter wavelengths. This is the updated and completely revised 5th edition of the most used introductory text in radio astronomy. It presents a unified treatment of the entire field from centimeter to sub-millimeter wavelengths. Topics covered include instruments, sensitivity considerations, observational methods and interpretations of the data recorded with both single dishes and interferometers. This text is useful to both students and experienced practicing astronomers. Besides making major updates and additions throughout the book, the authors have re-organized a number of chapters to more clearly separate basic theory from rapidly evolving practical aspects. Further, problem sets have been added at the end of each chapter.

  14. Searches for radio transients

    CERN Document Server

    Bhat, N D R

    2011-01-01

    Exploration of the transient Universe is an exciting and fast-emerging area within radio astronomy. Known transient phenomena range in time scales from sub-nanoseconds to years or longer, thus spanning a huge range in time domain and hinting a rich diversity in their underlying physical processes. Transient phenomena are likely locations of explosive or dynamic events and they offer tremendous potential to uncover new physics and astrophysics. A number of upcoming next-generation radio facilities and recent advances in computing and instrumentation have provided a much needed impetus for this field which has remained a relatively uncharted territory for the past several decades. In this paper we focus mainly on the class of phenomena that occur on very short time scales (i.e. from $\\sim$ milliseconds to $\\sim$ nanoseconds), known as {\\it fast transients}, the detections of which involve considerable signal processing and data management challenges, given the high time and frequency resolutions required in the...

  15. Die radio in Afrika

    Directory of Open Access Journals (Sweden)

    S. de Villiers

    1966-03-01

    Full Text Available Omvang van radio-uitsendings in en na Afrika. — Redes vir die versnelde tempo van uitbreiding. — Radio as die geskikste massa-kommunikasiemiddel vir Afrika. — Faktore wat die verspreiding bemoeilik. — Skouspelagtige toename in luistertalle.Toe Plinius, wat in die jaar 79 oorlede is, in sy „Historia Naturalis” verklaar het dat daar altyd iets nuuts uit Afrika afkomstig is, kon hy nouliks voorsien het dat die „iets" negentien eeue later in die lug sou setel wat hierdie reuse-vasteland oorspan — ’n Babelse spraakverwarring en ’n ongekende, verbete woorde-oorlog in die etergolwe, onder meer daarop bereken om die harte en hoofde van derduisendes te verower.

  16. Radio frequency ion source

    CERN Document Server

    Shen Guan Ren; Gao Fu; LiuNaiYi

    2001-01-01

    The study on Radio Frequency Ion Source is mainly introduced, which is used for CIAE 600kV ns Pulse Neutron Generator; and obtained result is also presented. The RF ion source consists of a diameter phi 25 mm, length 200 mm, coefficient of expansion =3.5 mA, beam current on target >=1.5 mA, beam spot =100 h.

  17. Regeneration of transgenic citrus plants under non selective conditions results in high-frequency recovery of plants with silenced transgenes.

    Science.gov (United States)

    Domínguez, A; Fagoaga, C; Navarro, L; Moreno, P; Peña, L

    2002-06-01

    Insertion of foreign DNA into plant genomes frequently results in the recovery of transgenic plants with silenced transgenes. To investigate to what extent regeneration under selective conditions limits the recovery of transgenic plants showing gene silencing in woody species, Mexican lime [ Citrus aurantifolia (Christm.) Swing.] plants were transformed with the p25 coat protein gene of Citrus tristeza virus (CTV) with or without selection for nptII and uidA. Strikingly, more than 30% of the transgenic limes regenerated under non-selective conditions had silenced transgenes, and in all cases silencing affected all the three transgenes incorporated. These results indicate that the frequency of transgene silencing may be greatly underestimated when the rate of silencing is estimated from the number of regenerants obtained under selective conditions. To our knowledge, this is the first report in which the frequency of gene silencing after transformation has been quantified. When the integration pattern of T-DNA was analyzed in silenced and non-silenced lines, it was observed that inverted repeats as well as direct repeats and even single integrations were able to trigger gene silencing. Gene silencing has often been associated with the insertion of DNA sequences as inverted repeats. Interestingly, here, direct repeats and single-copy insertions were found in both silenced and non-silenced lines, suggesting that the presence of inverted-repeat T-DNAs and the subsequent formation of dsRNAs triggering gene silencing cannot account for all silencing events.

  18. Combining Non Selective Gas Sensors on a Mobile Robot for Identification and Mapping of Multiple Chemical Compounds

    Directory of Open Access Journals (Sweden)

    Victor Hernandez Bennetts

    2014-09-01

    Full Text Available In this paper, we address the task of gas distribution modeling in scenarios where multiple heterogeneous compounds are present. Gas distribution modeling is particularly useful in emission monitoring applications where spatial representations of the gaseous patches can be used to identify emission hot spots. In realistic environments, the presence of multiple chemicals is expected and therefore, gas discrimination has to be incorporated in the modeling process. The approach presented in this work addresses the task of gas distribution modeling by combining different non selective gas sensors. Gas discrimination is addressed with an open sampling system, composed by an array of metal oxide sensors and a probabilistic algorithm tailored to uncontrolled environments. For each of the identified compounds, the mapping algorithm generates a calibrated gas distribution model using the classification uncertainty and the concentration readings acquired with a photo ionization detector. The meta parameters of the proposed modeling algorithm are automatically learned from the data. The approach was validated with a gas sensitive robot patrolling outdoor and indoor scenarios, where two different chemicals were released simultaneously. The experimental results show that the generated multi compound maps can be used to accurately predict the location of emitting gas sources.

  19. Combining non selective gas sensors on a mobile robot for identification and mapping of multiple chemical compounds.

    Science.gov (United States)

    Bennetts, Victor Hernandez; Schaffernicht, Erik; Pomareda, Victor; Lilienthal, Achim J; Marco, Santiago; Trincavelli, Marco

    2014-09-17

    In this paper, we address the task of gas distribution modeling in scenarios where multiple heterogeneous compounds are present. Gas distribution modeling is particularly useful in emission monitoring applications where spatial representations of the gaseous patches can be used to identify emission hot spots. In realistic environments, the presence of multiple chemicals is expected and therefore, gas discrimination has to be incorporated in the modeling process. The approach presented in this work addresses the task of gas distribution modeling by combining different non selective gas sensors. Gas discrimination is addressed with an open sampling system, composed by an array of metal oxide sensors and a probabilistic algorithm tailored to uncontrolled environments. For each of the identified compounds, the mapping algorithm generates a calibrated gas distribution model using the classification uncertainty and the concentration readings acquired with a photo ionization detector. The meta parameters of the proposed modeling algorithm are automatically learned from the data. The approach was validated with a gas sensitive robot patrolling outdoor and indoor scenarios, where two different chemicals were released simultaneously. The experimental results show that the generated multi compound maps can be used to accurately predict the location of emitting gas sources.

  20. How Healthcare Can Refocus on Its Super-Customers (Patients, n =1) and Customers (Doctors and Nurses) by Leveraging Lessons from Amazon, Uber, and Watson.

    Science.gov (United States)

    Kolker, Evelyne; Özdemir, Vural; Kolker, Eugene

    2016-06-01

    Healthcare is transforming with data-intensive omics technologies and Big Data. The "revolution" has already happened in technology, but the bottlenecks have shifted to the social domain: Who can be empowered by Big Data? Who are the users and customers? In this review and innovation field analysis, we introduce the idea of a "super-customer" versus "customer" and relate both to 21st century healthcare. A "super-customer" in healthcare is the patient, sample size of n = 1, while "customers" are the providers of healthcare (e.g., doctors and nurses). The super-customers have been patients, enabled by unprecedented social practices, such as the ability to track one's physical activities, personal genomics, patient advocacy for greater autonomy, and self-governance, to name but a few. In contrast, the originally intended customers-providers, doctors, and nurses-have relatively lagged behind. With patients as super-customers, there are valuable lessons to be learned from industry examples, such as Amazon and Uber. To offer superior quality service, healthcare organizations have to refocus on the needs, pains, and aspirations of their super-customers by enabling the customers. We propose a strategic solution to this end: the PPT-DAM (People-Process-Technology empowered by Data, Analytics, and Metrics) approach. When applied together with the classic Experiment-Execute-Evaluate iterative methodology, we suggest PPT-DAM is an extremely powerful approach to deliver quality health services to super-customers and customers. As an example, we describe the PPT-DAM implementation by the Benchmarking Improvement Program at the Seattle Children's Hospital. Finally, we forecast that cognitive systems in general and IBM Watson in particular, if properly implemented, can bring transformative and sustainable capabilities in healthcare far beyond the current ones.

  1. Compact radio cores in radio-quiet AGNs

    CERN Document Server

    Maini, Alessandro; Norris, Ray P; Giovannini, Gabriele; Spitler, Lee R

    2016-01-01

    The mechanism of radio emission in radio-quiet (RQ) active galactic nuclei (AGN) is still debated and might arise from the central AGN, from star formation activity in the host, or from either of these sources. A direct detection of compact and bright radio cores embedded in sources that are classified as RQ can unambiguously determine whether a central AGN significantly contributes to the radio emission. We search for compact, high-surface-brightness radio cores in RQ AGNs that are caused unambiguously by AGN activity. We used the Australian Long Baseline Array to search for compact radio cores in four RQ AGNs located in the Extended Chandra Deep Field South (ECDFS). We also targeted four radio-loud (RL) AGNs as a control sample. We detected compact and bright radio cores in two AGNs that are classified as RQ and in one that is classified as RL. Two RL AGNs were not imaged because the quality of the observations was too poor. We report on a first direct evidence of radio cores in RQ AGNs at cosmological reds...

  2. Radio emision from supernova remnants

    Science.gov (United States)

    Dubner, G.

    2016-06-01

    The vast majority of supernova remnants (SNRs) in our Galaxy and nearby galaxies have been discovered through radio observations, and only a very small number of the SNRs catalogued in the Milky Way have not been detected in the radio band, or are poorly defined by current radio observations. The study of the radio emission from SNRs is an excellent tool to investigate morphological characteristics, marking the location of shock fronts and contact discontinuities; the presence, orientation and intensity of the magnetic field; the energy spectrum of the emitting particles; and the dynamical consequences of the interaction with the circumstellar and interstellar medium. I will review the present knowledge of different important aspects of radio remnants and their impact on the interstellar gas. Also, new radio studies of the Crab Nebula carried out with the Karl Jansky Very Large Array (JVLA) at 3 GHz and with ALMA at 100 GHz, will be presented.

  3. Flexible Adaptation in Cognitive Radios

    CERN Document Server

    Li, Shujun

    2013-01-01

    This book provides an introduction to software-defined radio and cognitive radio, along with methodologies for applying knowledge representation, semantic web, logic reasoning and artificial intelligence to cognitive radio, enabling autonomous adaptation and flexible signaling. Readers from the wireless communications and software-defined radio communities will use this book as a reference to extend software-defined radio to cognitive radio, using the semantic technology described. Readers with a background in semantic web and artificial intelligence will find in this book the application of semantic web and artificial intelligence technologies to wireless communications. For readers in networks and network management, this book presents a new approach to enable interoperability, collaborative optimization and flexible adaptation of network components. Provides a comprehensive ontology covering the core concepts of wireless communications using a formal language; Presents the technical realization of using a ...

  4. Software defined radio architectures evaluation

    OpenAIRE

    Palomo, Alvaro; Villing, Rudi; Farrell, Ronan

    2008-01-01

    This paper presents an performance evaluation of GNU Radio and OSSIE, two open source Software Defined Radio (SDR) architectures. The two architectures were compared by running implementations of a BPSK waveform utilising a software loopback channel on each. The upper bound full duplex throughput was found to be around 700kbps in both cases, though OSSIE was slightly faster than GNU Radio. CPU and memory loads did not differ significantly.

  5. Uzaybimer Radio Telescope Control System

    Science.gov (United States)

    Balbay, R.; Öz, G. K.; Arslan, Ö.; Özeren, F. F.; Küçük, İ.

    2016-12-01

    A 13 meters former NATO radar is being converted into a radio telescope. The radio telescope is controlled by a system which has been developed at UZAYBİMER. The Telescope Control System(TCS) has been designed using modern industrial systems. TCS has been developed in LabView platform in which works Windows embedded OS. The position feedback used on radio telescopes is an industrial EtherCAT standard. ASCOM library is used for astronomical calculations.

  6. Non-selective regulation of peroxide and superoxide resistance genes by PerR in Campylobacter jejuni

    Directory of Open Access Journals (Sweden)

    Jong-Chul eKim

    2015-02-01

    Full Text Available Campylobacter jejuni is an important foodborne pathogen. The molecular mechanisms for the regulation of oxidative stress resistance have not yet been understood fully in this bacterium. In this study, we investigated how PerR (peroxide stress regulator modulates the transcriptional regulation of both peroxide and superoxide resistance genes in C. jejuni, particularly under oxidative stress conditions. The transcriptional levels of ahpC, katA, and sodB were substantially increased by aeration and oxidant exposure. Interestingly, a perR mutation completely abrogated the transcriptional response of ahpC, katA and sodB to oxidants. Furthermore, we demonstrated that perR transcription was reduced by aeration and oxidant exposure. In contrast to the unique role of PerR homologs in peroxide stress regulation in other bacteria, interestingly, C. jejuni PerR directly regulates the transcription of sodB, the most important gene in superoxide defense, as evidenced by the alteration of sodB transcription by the perR mutation and direct binding of rPerR to the sodB promoter. In addition, we also observed notable morphological changes in C. jejuni from spiral rods to coccoid morphology under aerobic conditions. Based on the intracellular ATP levels, C. jejuni entered a viable-but-non-culturable state under aerobic conditions. These findings clearly demonstrate that C. jejuni possesses a unique regulatory mechanism of oxidative stress defense that does not specifically distinguish between peroxide and superoxide defense, and PerR plays a pivotal role in this non-selective regulation of oxidative stress resistance in C. jejuni.

  7. The incentive amplifying effects of nicotine are reduced by selective and non-selective dopamine antagonists in rats.

    Science.gov (United States)

    Palmatier, Matthew I; Kellicut, Marissa R; Brianna Sheppard, A; Brown, Russell W; Robinson, Donita L

    2014-11-01

    Nicotine is a psychomotor stimulant with 'reinforcement enhancing' effects--the actions of nicotine in the brain increase responding for non-nicotine rewards. We hypothesized that this latter effect of nicotine depends on increased incentive properties of anticipatory cues; consistent with this hypothesis, multiple laboratories have reported that nicotine increases sign tracking, i.e. approach to a conditioned stimulus (CS), in Pavlovian conditioned-approach tasks. Incentive motivation and sign tracking are mediated by mesolimbic dopamine (DA) transmission and nicotine facilitates mesolimbic DA release. Therefore, we hypothesized that the incentive-promoting effects of nicotine would be impaired by DA antagonists. To test this hypothesis, separate groups of rats were injected with nicotine (0.4mg/kg base) or saline prior to Pavlovian conditioning sessions in which a CS (30s illumination of a light or presentation of a lever) was immediately followed by a sweet reward delivered in an adjacent location. Both saline and nicotine pretreated rats exhibited similar levels of conditioned approach to the reward location (goal tracking), but nicotine pretreatment significantly increased approach to the CS (sign tracking), regardless of type (lever or light). The DAD1 antagonist SCH-23390 and the DAD2/3 antagonist eticlopride reduced conditioned approach in all rats, but specifically reduced goal tracking in the saline pretreated rats and sign tracking in the nicotine pretreated rats. The non-selective DA antagonist flupenthixol reduced sign-tracking in nicotine rats at all doses tested; however, only the highest dose of flupenthixol reduced goal tracking in both nicotine and saline groups. The reductions in conditioned approach behavior, especially those by SCH-23390, were dissociated from simple motor suppressant effects of the antagonists. These experiments are the first to investigate the effects of dopaminergic drugs on the facilitation of sign-tracking engendered by

  8. Radio-induced brain lesions

    Directory of Open Access Journals (Sweden)

    Gorgan Mircea Radu

    2014-03-01

    Full Text Available Introduction : Radiotherapy, an important tool in multimodal oncologic treatment, can cause radio-induced brain lesion development after a long period of time following irradiation.

  9. Internet Resources for Radio Astronomy

    Science.gov (United States)

    Andernach, H.

    A subjective overview of Internet resources for radio-astronomical information is presented. Basic observing techniques and their implications for the interpretation of publicly available radio data are described, followed by a discussion of existing radio surveys, their level of optical identification, and nomenclature of radio sources. Various collections of source catalogues and databases for integrated radio source parameters are reviewed and compared, as well as the web interfaces to interrogate the current and ongoing large-area surveys. Links to radio observatories with archives of raw (uv-) data are presented, as well as services providing images, both of individual objects or extracts (``cutouts'') from large-scale surveys. While the emphasis is on radio continuum data, a brief list of sites providing spectral line data, and atomic or molecular information is included. The major radio telescopes and surveys under construction or planning are outlined. A summary is given of a search for previously unknown optically bright radio sources, as performed by the students as an exercise, using Internet resources only. Over 200 different links are mentioned and were verified, but despite the attempt to make this report up-to-date, it can only provide a snapshot of the situation as of mid-1998.

  10. Radio Frequency Anechoic Chamber Facility

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Supports the design, manufacture, and test of antenna systems. The facility is also used as an electromagnetic compatibility/radio frequency interference...

  11. Military Mail Radio

    Directory of Open Access Journals (Sweden)

    Bîlbîie Răduţ

    2015-12-01

    Full Text Available Cultural and scientific personalities from the army, military experts and creators of the doctrine have collaborated with the radio from the beginnings of radiophony, the educational role of this new, persuasive communication channel being evident not only for Romania or the Romanian army but also for all the countries that had radiophony services. This happens in the context of the end of the crisis and the start of economic and social development, promoting culture, creating a solid class of peasants with a certain social status, in villages, together with the priest, teacher and gendarme, increasing of the number of subscriptions and development of the Romanian radiophony.

  12. Radio Frequency Identification

    Indian Academy of Sciences (India)

    V Rajaraman

    2017-06-01

    Radio Frequency Identification (RFID) has been around sinceearly 2000. Its use has currently become commonplace as thecost of RFID tags has rapidly decreased. RFID tags have alsobecome more ‘intelligent’ with the incorporation of processorsand sensors in them. They are widely used now in manyinnovative ways. RFIDs are an integral part of Internet ofThings (IOT) and IT systems of smart cities. In this article,we introduce the technology used by RFID systems, illustratetheir use in several applications, and discuss problems of privacyand security when they are used.

  13. Treatment with non-selective beta blockers is associated with reduced severity of systemic inflammation and improved survival of patients with acute-on-chronic liver failure

    DEFF Research Database (Denmark)

    Mookerjee, Rajeshwar P; Pavesi, Marco; Thomsen, Karen Louise

    2016-01-01

    BACKGROUND AND AIMS: Non-selective beta-blockers (NSBBs) have been shown to have deleterious outcomes in patients with refractory ascites, alcoholic hepatitis and spontaneous bacterial peritonitis leading many physicians to stop the drug in these cases. Acute on chronic liver failure (ACLF...

  14. Growth characteristics and ion contents of non-selected and salt-selected callus lines of highbush blueberry (Vacdnium corymbosum) cultivars Blue Crop and Denise Blue.

    Science.gov (United States)

    Muralitharan, M S; Van Steveninck, R F; Chandler, S E

    1990-07-01

    Non-selected and sodium chloride selected callus lines of Vacdnium corymbosum L.cv Blue Crop and cv. Denise Blue were grown on media supplemented with 0-100 mM NaCl. For both cultivars, fresh weight and dry weight yields were greater in selected lines on all levels of NaCl. Selected lines of Blue Crop displayed better growth than selected lines of Denise Blue at most concentrations of NaCl. Internal Na(+) and Cl(-) concentrations in selected and non-selected lines of both cultivars increased as external concentration was raised. However, selected lines of Blue Crop and Denise Blue accumulated more Na(+) and Cl(-) than non-selected lines. Selected lines of both cultivars maintained higher levels of K(+) than non-selected lines on all external NaCl levels. Selected lines of Blue Crop had higher levels of Na(+) and Cl(-) than that of Denise Blue. The results suggest Na(+) and Cl(-) accumulation could be a mechanism allowing better growth in selected lines at moderate salinity levels (50-75 mM NaCl).

  15. Comparison of subtypes of Listeria monocytogenes isolates from naturally contaminated watershed samples using a combination of non-selective and selective enrichment methods

    Science.gov (United States)

    Two enrichment methods for Listeria monocytogenes using Immuno Magnetic Separation were tested to determine if they selected the same subtypes of isolates. Both methods included a non-selective enrichment and one included subculture in Fraser Broth. Naturally contaminated watershed samples from the ...

  16. Evaluation of GNU Radio Platform Enhanced for Hardware Accelerated Radio Design

    OpenAIRE

    Karve, Mrudula Prabhakar

    2010-01-01

    The advent of software radio technology has enabled radio developers to design and imple- ment radios with great ease and flexibility. Software radios are effective in experimentation and development of radio designs. However, they have limitations when it comes to high- speed, high-throughput designs. This limitation can be overcome by introducing a hardware element to the software radio platform. Enhancing GNU Radio for Hardware Accelerated Radio Design project implements suc...

  17. The coexistence of cognitive radio and radio astronomy

    NARCIS (Netherlands)

    Bentum, Marinus Jan; Boonstra, A.J.; Baan, W.A.

    2009-01-01

    An increase of the efficiency of spectrum usage requires the development of new communication techniques. Cognitive radio may be one of those new technique, which uses unoccupied frequency bands for communications. This will lead to more power in the bands and therefore an increasing level of Radio

  18. The coexistence of cognitive radio and radio astronomy

    NARCIS (Netherlands)

    Bentum, M.J.; Boonstra, A.J.; Baan, W.A.

    2009-01-01

    An increase of the efficiency of spectrum usage requires the development of new communication techniques. Cognitive radio may be one of those new technique, which uses unoccupied frequency bands for communications. This will lead to more power in the bands and therefore an increasing level of Radio

  19. Radio Quiet AGN

    CERN Document Server

    Czerny, B; Karas, V; Ponti, G

    2005-01-01

    Active Galactic Nuclei are powered by accretion onto massive black holes. Although radio-quiet objects are not as spectacular sources of very high energy photons as radio-loud ones this class of objects also represents a challenge for modeling high energy processes close to a black hole. Both a hot optically thin plasma and a cooler optically thick accretion disk are usually thought to be present in the vicinity of a black hole although the details of the accretion flow are still under discussion. The role of the disk seems to decrease with a drop in the Eddington ratio: in sources like quasars and Narrow Line Seyfert 1 galaxies disk flow dominates while in Seyfert galaxies the disk retreats, and in sources like LINERS or Sgr A* a disk is most likely absent. Shocks and reconnections are possibly taking place in an inner hot flow and in the magnetic corona above the cold disk. Uncollimated outflow is also present and it may carry significant fraction of available mass and energy.

  20. Radio astronomy from space

    Science.gov (United States)

    Woan, G.

    2011-04-01

    At frequencies below about 30 MHz, radio astronomy becomes increasingly difficult from the Earth's surface, mainly due to a combination of poor ionospheric seeing and strong terrestrial interference. The obvious move is to space, either as free-flying spacecraft or with a telescope located somewhere on the Moon. All the major space agencies have a renewed interest in the Moon as a site for exploration and science, and low-frequency radio astronomy is probably the strongest of the astronomical objectives put forward in these programmes. Although the Sun is a strong source of interference in extra-solar system work, it is also a prime target for study in itself. A constellation of satellites (as proposed for the SIRA mission) would be able to image both the Sun and the inner heliosphere over the entire low-frequency band. Here we investigate some of the advantages and limitations of astronomy at these very low frequencies, using space- and lunar-based antennas.

  1. 78 FR 32165 - Commercial Radio Operators; Correction

    Science.gov (United States)

    2013-05-29

    ... COMMISSION 47 CFR Part 0 Commercial Radio Operators; Correction AGENCY: Federal Communication Commission...) Administers the Commission's commercial radio operator program (part 13 of this chapter); the Commission's... rules concerning radio operator licenses for maritime and aviation in order to reduce...

  2. Radio Relics in Cosmological Simulations

    Indian Academy of Sciences (India)

    M. Hoeft; S. E. Nuza; S. Gottlöber; R. J. van Weeren; H. J. A. Röttgering; M. Brüggen

    2011-12-01

    Radio relics have been discovered in many galaxy clusters. They are believed to trace shock fronts induced by cluster mergers. Cosmological simulations allow us to study merger shocks in detail since the intra-cluster medium is heated by shock dissipation. Using high resolution cosmological simulations, identifying shock fronts and applying a parametric model for the radio emission allows us to simulate the formation of radio relics. We analyze a simulated shock front in detail. We find a rather broad Mach number distribution. The Mach number affects strongly the number density of relativistic electrons in the downstream area, hence, the radio luminosity varies significantly across the shock surface. The abundance of radio relics can be modeled with the help of the radio power probability distribution which aims at predicting radio relic number counts. Since the actual electron acceleration efficiency is not known, predictions for the number counts need to be normalized by the observed number of radio relics. For the characteristics of upcoming low frequency surveys we find that about thousand relics are awaiting discovery.

  3. Tuning in to pavement radio

    NARCIS (Netherlands)

    Ellis, S.D.K.

    1989-01-01

    This article describes a phenomenon known all over Africa, for which there is no really satisfactory term in English but which is summed up in the French term 'radio trottoir', literally 'pavement radio'. It may be defined as the popular and unofficial discussion of current affairs in Africa,

  4. Cognitive Radio for Emergency Networks

    NARCIS (Netherlands)

    Zhang, Q.; Kokkeler, Andre B.J.; Smit, Gerardus Johannes Maria

    2006-01-01

    In the scope of the Adaptive Ad-hoc Freeband (AAF) project, an emergency network built on top of Cognitive Radio is proposed to alleviate the spectrum shortage problem which is the major limitation for emergency networks. Cognitive Radio has been proposed as a promising technology to solve todayâ?~B

  5. Radio Loud AGNs are Mergers

    CERN Document Server

    Chiaberge, Marco; Lotz, Jennifer; Norman, Colin

    2015-01-01

    We measure the merger fraction of Type 2 radio-loud and radio-quiet active galactic nuclei at z>1 using new samples. The objects have HST images taken with WFC3 in the IR channel. These samples are compared to the 3CR sample of radio galaxies at z>1 and to a sample of non-active galaxies. We also consider lower redshift radio galaxies with HST observations and previous generation instruments (NICMOS and WFPC2). The full sample spans an unprecedented range in both redshift and AGN luminosity. We perform statistical tests to determine whether the different samples are differently associated with mergers. We find that all (92%) radio-loud galaxies at z>1 are associated with recent or ongoing merger events. Among the radio-loud population there is no evidence for any dependence of the merger fraction on either redshift or AGN power. For the matched radio-quiet samples, only 38% are merging systems. The merger fraction for the sample of non-active galaxies at z>1 is indistinguishable from radio-quiet objects. This...

  6. Relics of Double Radio Sources

    CERN Document Server

    Dwarakanath, K S

    2009-01-01

    We have formed a new sample which consists of extended extragalactic radio sources without obvious active galactic nuclei (AGN) in them. Most of these sources appear to be dead double radio sources. These sources with steep spectra ($\\alpha < $ -1.8; S $\\propto \

  7. Cognitive Radio for Emergency Networks

    NARCIS (Netherlands)

    Zhang, Qiwei; Kokkeler, A.B.J.; Smit, G.J.M.

    2006-01-01

    In the scope of the Adaptive Ad-hoc Freeband (AAF) project, an emergency network built on top of Cognitive Radio is proposed to alleviate the spectrum shortage problem which is the major limitation for emergency networks. Cognitive Radio has been proposed as a promising technology to solve todayâ?~B

  8. The Radio Phenomenon in Italy.

    Science.gov (United States)

    Faenza, Roberto

    One in a series of studies of experiments in new audiovisual techniques in Europe and the situations in some member countries, this paper traces the development of radio in Italy. Opposing views about radio broadcasting (public monopoly vs. freedom of broadcasting) are examined, and the various political and legal aspects of communications in…

  9. Radio outburst of BL Lacertae

    Science.gov (United States)

    Buemi, C. S.; Leto, P.; Trigilio, C.; Umana, G.; Giroletti, M.; Orienti, M.; Raiteri, C. M.; Villata, M.; Bach, U.

    2013-04-01

    We report on extremely high radio flux of BL Lacertae at 43 and 8 GHz. Observations at 43 GHz with the 32 m radio telescope in Noto (Italy) revealed a flux density of 10.5 +/- 0.2 Jy on 2013 April 10.65, while observations at 8 GHz with the 32 m radio telescope in Medicina (Italy) detected a flux density of 8.2 +/- 0.7 Jy on April 12.22. These extremely high radio fluxes show that the radio activity likely correlated to the strong optical, near-infrared, and gamma-ray activity of 2011-2012 (see ATels #4028, #4031, #4155, #4271, #4277, #4349, #4565, #4600), and X-ray activity of late 2012 (ATels #4557, #4627), is far to be exhausted.

  10. Radio Emission from Globular Clusters

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Radio emission of globular clusters is studied by analyzing the VLA radio survey data of the NVSS and FIRST. We find that 13 clusters have radio sources within their half-mass radii of clusters. Sources detected previously in NGC 7078and NGC 6440 are identified. Pulsars in NGC 6121, NGC 6440 and NGC 7078cannot be detected because of the insufficient survey sensitivity and resolution.There may be a pulsar in the core of Terzan 1. The nature of the extended radio source near the core of NGC 6440 remains unclear. In the core of a globular cluster,there may be many neutron stars or an intermediate mass black hole, but this cannot be clarified with the current radio observations.

  11. CONSTRAINING RADIO EMISSION FROM MAGNETARS

    Energy Technology Data Exchange (ETDEWEB)

    Lazarus, P.; Kaspi, V. M.; Dib, R. [Department of Physics, Rutherford Physics Building, McGill University, 3600 University Street, Montreal, Quebec H3A 2T8 (Canada); Champion, D. J. [Max-Planck-Institut fuer Radioastronomie, Auf dem Huegel 69, 53121 Bonn (Germany); Hessels, J. W. T., E-mail: plazar@physics.mcgill.ca [Netherlands Institute for Radio Astronomy (ASTRON), Postbus 2, 7990 AA Dwingeloo (Netherlands)

    2012-01-10

    We report on radio observations of five magnetars and two magnetar candidates carried out at 1950 MHz with the Green Bank Telescope in 2006-2007. The data from these observations were searched for periodic emission and bright single pulses. Also, monitoring observations of magnetar 4U 0142+61 following its 2006 X-ray bursts were obtained. No radio emission was detected for any of our targets. The non-detections allow us to place luminosity upper limits of L{sub 1950} {approx}< 1.60 mJy kpc{sup 2} for periodic emission and L{sub 1950,single} {approx}< 7.6 Jy kpc{sup 2} for single pulse emission. These are the most stringent limits yet for the magnetars observed. The resulting luminosity upper limits together with previous results are discussed, as is the importance of further radio observations of radio-loud and radio-quiet magnetars.

  12. Constraining Radio Emission from Magnetars

    CERN Document Server

    Lazarus, Patrick; Champion, David J; Hessels, Jason W T; Dib, Rim

    2011-01-01

    We report on radio observations of five magnetars and two magnetar candidates carried out at 1950 MHz with the Green Bank Telescope in 2006-2007. The data from these observations were searched for periodic emission and bright single pulses. Also, monitoring observations of magnetar 4U0142+61 following its 2006 X-ray bursts were obtained. No radio emission was detected was detected for any of our targets. The non-detections allow us to place luminosity upper limits (at 1950 MHz) of approximately L < 1.60 mJy kpc^2 for periodic emission and L < 7.6 Jy kpc^2 for single pulse emission. These are the most stringent limits yet for the magnetars observed. The resulting luminosity upper limits together with previous results are discussed, as is the importance of further radio observations of radio-loud and radio-quiet magnetars.

  13. Radio propagation measurement and channel modelling

    CERN Document Server

    Salous, Sana

    2013-01-01

    While there are numerous books describing modern wireless communication systems that contain overviews of radio propagation and radio channel modelling, there are none that contain detailed information on the design, implementation and calibration of radio channel measurement equipment, the planning of experiments and the in depth analysis of measured data. The book would begin with an explanation of the fundamentals of radio wave propagation and progress through a series of topics, including the measurement of radio channel characteristics, radio channel sounders, measurement strategies

  14. CURIE: Cubesat Radio Interferometry Experiment

    Science.gov (United States)

    Sundkvist, D. J.; Saint-Hilaire, P.; Bain, H. M.; Bale, S. D.; Bonnell, J. W.; Hurford, G. J.; Maruca, B.; Martinez Oliveros, J. C.; Pulupa, M.

    2016-12-01

    The CUbesat Radio Interferometry Experiment (CURIE) is a proposed two-element radio interferometer, based on proven and developed digital radio receivers and designed to fit within a Cubesat platform. CURIE will launch as a 6U Cubesat and then separate into two 3U Cubesats once in orbit. CURIE measures radio waves from 0.1-19MHz, which must be measured from space, as those frequencies fall below the cutoff imposed by Earth's ionosphere. The principal science objective for CURIE is to use radio interferometry to study radio burst emissions from solar eruptive events such as flares and coronal mass ejections (CMEs) in the inner heliosphere, providing observations important for our understanding of the heliospheric space weather environment. The influence of space weather can be felt at Earth and other planets, as radiation levels increase and lead to auroral activity and geomagnetic effects. CURIE will be able to determine the location and size of radio burst source regions and then to track their movement outward from the Sun. In addition to the primary objective CURIE will measure the gradients of the local ionospheric density and electron temperature on the spatial scale of a few kilometers, as well as create an improved map of the radio sky at these unexplored frequencies. A space based radio interferometry observatory has long been envisioned, in orbit around the Earth or the Moon, or on the far side of the Moon. Beyond its important science objectives, CURIE will prove that the concept of a dedicated space-based interferometer can be realized by using relatively cheap Cubesats. CURIE will therefore not only provide new important science results but also serve as a pathfinder in the development of new space-based radio observation techniques for helio- and astro-physics.

  15. The faint radio sky: radio astronomy becomes mainstream

    Science.gov (United States)

    Padovani, Paolo

    2016-09-01

    Radio astronomy has changed. For years it studied relatively rare sources, which emit mostly non-thermal radiation across the entire electromagnetic spectrum, i.e. radio quasars and radio galaxies. Now, it is reaching such faint flux densities that it detects mainly star-forming galaxies and the more common radio-quiet active galactic nuclei. These sources make up the bulk of the extragalactic sky, which has been studied for decades in the infrared, optical, and X-ray bands. I follow the transformation of radio astronomy by reviewing the main components of the radio sky at the bright and faint ends, the issue of their proper classification, their number counts, luminosity functions, and evolution. The overall "big picture" astrophysical implications of these results, and their relevance for a number of hot topics in extragalactic astronomy, are also discussed. The future prospects of the faint radio sky are very bright, as we will soon be flooded with survey data. This review should be useful to all extragalactic astronomers, irrespective of their favourite electromagnetic band(s), and even stellar astronomers might find it somewhat gratifying.

  16. A Radio Astronomy Science Education Partnership - GAVRT and Radio JOVE

    Science.gov (United States)

    Higgins, C. A.; Thieman, J. R.; Bunnell, K.; Soholt, G.

    2009-12-01

    The planet Jupiter provides an excellent subject to educate, engage, and inspire students and teachers to learn science. The Goldstone Apple-Valley Radio Telescope (GAVRT) program (http://www.lewiscenter.org/gavrt) and The Radio JOVE project (http://radiojove.gsfc.nasa.gov) each have a long history of allowing students and teachers to interact with scientists and real radio telescopes. The upcoming Juno mission to Jupiter (2011 launch) allows both GAVRT and Radio JOVE to combine efforts and engage with the NASA Juno mission, thus increasing the excitement and learning potential for teachers, students, and the general public. Teachers can attend workshops for training to operate a 34-meter radio telescope and/or build their own simple radio telescope, both of which can be used directly in the classroom. We will overview some classroom activities and highlight some teacher-student experiences. In addition, we will update our efforts on greater Web-based control of the radio telescopes, as well as highlight our upcoming workshops to allow better access for teachers in different parts of the Country.

  17. The faint radio sky: radio astronomy becomes mainstream

    CERN Document Server

    Padovani, Paolo

    2016-01-01

    Radio astronomy has changed. For years it studied relatively rare sources, which emit mostly non-thermal radiation across the entire electromagnetic spectrum, i.e. radio quasars and radio galaxies. Now it is reaching such faint flux densities that it detects mainly star-forming galaxies and the more common radio-quiet active galactic nuclei. These sources make up the bulk of the extragalactic sky, which has been studied for decades in the infrared, optical, and X-ray bands. I follow the transformation of radio astronomy by reviewing the main components of the radio sky at the bright and faint ends, the issue of their proper classification, their number counts, luminosity functions, and evolution. The overall "big picture" astrophysical implications of these results, and their relevance for a number of hot topics in extragalactic astronomy, are also discussed. The future prospects of the faint radio sky are very bright, as we will soon be flooded with survey data. This review should be useful to all extragalac...

  18. The Radio Language Arts Project: adapting the radio mathematics model.

    Science.gov (United States)

    Christensen, P R

    1985-01-01

    Kenya's Radio Language Arts Project, directed by the Academy for Educational Development in cooperation with the Kenya Institute of Education in 1980-85, sought to teach English to rural school children in grades 1-3 through use of an intensive, radio-based instructional system. Daily 1/2 hour lessons are broadcast throughout the school year and supported by teachers and print materials. The project further was aimed at testing the feasibility of adaptation of the successful Nicaraguan Radio Math Project to a new subject area. Difficulties were encountered in articulating a language curriculum with the precision required for a media-based instructional system. Also a challenge was defining the acceptable regional standard for pronunciation and grammar; British English was finally selected. An important modification of the Radio Math model concerned the role of the teacher. While Radio Math sought to reduce the teacher's responsibilities during the broadcast, Radio Language Arts teachers played an important instructional role during the English lesson broadcasts by providing translation and checks on work. Evaluations of the Radio language Arts Project suggest significant gains in speaking, listening, and reading skills as well as high levels of satisfaction on the part of parents and teachers.

  19. Implementing Software Defined Radio

    CERN Document Server

    Grayver, Eugene

    2013-01-01

    Software Defined Radio makes wireless communications easier, more efficient, and more reliable. This book bridges the gap between academic research and practical implementation. When beginning a project, practicing engineers, technical managers, and graduate students can save countless hours by considering the concepts presented in these pages. The author covers the myriad options and trade-offs available when selecting an appropriate hardware architecture. As demonstrated here, the choice between hardware- and software-centric architecture can mean the difference between meeting an aggressive schedule and bogging down in endless design iterations. Because of the author’s experience overseeing dozens of failed and successful developments, he is able to present many real-life examples. Some of the key concepts covered are: Choosing the right architecture for the market – laboratory, military, or commercial Hardware platforms – FPGAs, GPPs, specialized and hybrid devices Standardization efforts to ens...

  20. Correlation radio range finder

    Directory of Open Access Journals (Sweden)

    A. Sorochan

    2012-10-01

    Full Text Available In work widely known methods of range measuring are short characterized. The basic attention is given features of signal processing in a correlation method of range measuring. The signal with angular modulation with one-voice-frequency fluctuation is used as a probing signal. The absence of Doppler effect on the formation of the correlation integral, the frequency instability of the transmitter, the phase change on reflection from the target is presented. It is noticed that the result of signal processing in the range measuring instrument is reduced to formation on an exit one-voice-frequency harmonious fluctuation equal to modulating frequency that provides high characteristics of a radio range finder.

  1. MUSIC RADIO-JOURNALISM

    Directory of Open Access Journals (Sweden)

    Dubovtceva Ludmila I.

    2014-04-01

    Full Text Available The article is based on years of practical experience, the author highlights the main radio genres in which music correspondent, music reviewer, music commentator, and music leading and a disc jockey work. Theoretical principles of their creative activities are analyzed in common journalistic genres, such as interview, reportage, talk show, live broadcast, radiofilm, as well as specialized genres like concert on demand and music competition. Journalist’ speech is seen as a logical element, the incoming with music in art-structural relationships. However, it does not become the predominant sound layer and aims to harmonious correlation or local penetration into music opus. In addition, important links in music journalism are defined the auxiliary "offscreen" editor's job and keeping the original sound archive. The author cites a number of own work examples on the air.

  2. Teaching radio astronomy with Affordable Small Radio Telescope (ASRT)

    Science.gov (United States)

    Joshi, Bhal Chandra

    A simple, easy to build and portable radio telescope, called Affordable Small Radio Telescope (ASRT), has been developed by the Radio Physics Laboratory (RPL), a radio astronomy teaching unit associated with the National Centre for Radio Astrophysics (TIFR) and Inter-University Centre for Astronomy and Astrophysics (IUCAA), which are two premier astronomy institutes in India. ASRT consists of off-the-shelf available Direct to Home television dishes and is easy to assemble. Our design is scalable from simple very low cost telescope to more complex yet moderately costing instrument. ASRT provides a platform for demonstrating radio physics concepts through simple hands-on experiment as well as for carrying out solar monitoring by college/University students. The presentation will highlight the concept of ASRT and the different experiments that can be carried out using it. The solar monitoring observations will be discussed along-with details of methods for calibrating these measurements. The pedagogical usefulness of ASRT in introducing undergraduatephysics students to astrophysics, measurements and analysis methods used in radio astronomy will also be discussed. Use of ASRT in the last three years in the programs of RPL, namely the annual Radio Astronomy Winter School for College students (RAWSC) and Pulsar Observing for Students (POS) is also presented. This year a new program was initiated to form a virtual group of an ASRT community, which will not only share their measurements, but also think of improving the pedagogical usefulness of ASRT by innovative experiments. This initiative is presented with the best practices drawn from our experience in using ASRT as a tool for student training in space sciences. The talk will also point out future ideas in involving a larger body of students in simple radio astronomy experiments with the ASRT, which RPL is likely to nucleate as part of its mandate.

  3. South African Radio League Introduction to Amateur Radio: A study guide for the Radio Amateur Examination

    CSIR Research Space (South Africa)

    Burger, Chris

    2016-01-01

    Full Text Available recognition of amateur radio licences. South African radio amateurs can exercise their privileges in more than 80 countries and territories with minimal paperwork. In exchange, we have an obligation to ensure that all licence holders possess a minimum level...

  4. Radio Astronomy Explorer /RAE/. I - Observations of terrestrial radio noise.

    Science.gov (United States)

    Herman, J. R.; Caruso, J. A.; Stone, R. G.

    1973-01-01

    Radio Astronomy Explorer (RAE) I data are analyzed to establish characteristics of HF terrestrial radio noise at an altitude of about 6000 km. Time and frequency variations in amplitude of the observed noise well above cosmic noise background are explained on the basis of temporal and spatial variations in ionospheric critical frequency coupled with those in noise source distributions. It is shown that terrestrial radio noise regularly breaks through the ionosphere and reaches RAE with magnitudes 15 dB and more above cosmic noise background, on frequencies above the F-layer critical frequency.

  5. Dust tori in radio galaxies

    CERN Document Server

    van der Wolk, G; Peletier, R F; Pel, J W

    2009-01-01

    We investigate the validity of the quasar - radio galaxy unification scenario and determine the presence of dust tori among radio galaxies of various types. Actively accreting supermassive black holes in the centres of radio galaxies may be uncovered through their dust tori reradiating the optical and ultraviolet continuum in mid-infrared bands. Using VISIR on the VLT, we have obtained sub-arcsecond (~0.40") resolution N-band images, at a wavelength of 11.85 micron, of the nuclei of a sample of 27 radio galaxies of four types in the redshift range z=0.006-0.156. The sample consists of 8 edge-darkened, low-power Fanaroff-Riley class I (FR-I) radio galaxies, 6 edge-brightened, class II (FR-II) radio galaxies displaying low-excitation optical emission, 7 FR-IIs displaying high-excitation optical emission, and 6 FR-II broad emission line radio galaxies. Out of the sample of 27 objects, 10 nuclei are detected and several have constraining non-detections at 10 sigma sensitivities of 7 mJy. On the basis of the core ...

  6. Radio emission in Mercury magnetosphere

    Science.gov (United States)

    Varela, J.; Reville, V.; Brun, A. S.; Pantellini, F.; Zarka, P.

    2016-10-01

    Context. Active stars possess magnetized wind that has a direct impact on planets that can lead to radio emission. Mercury is a good test case to study the effect of the solar wind and interplanetary magnetic field (IMF) on radio emission driven in the planet magnetosphere. Such studies could be used as proxies to characterize the magnetic field topology and intensity of exoplanets. Aims: The aim of this study is to quantify the radio emission in the Hermean magnetosphere. Methods: We use the magnetohydrodynamic code PLUTO in spherical coordinates with an axisymmetric multipolar expansion for the Hermean magnetic field, to analyze the effect of the IMF orientation and intensity, as well as the hydrodynamic parameters of the solar wind (velocity, density and temperature), on the net power dissipated on the Hermean day and night side. We apply the formalism derived by Zarka et al. (2001, Astrophys. Space Sci., 277, 293), Zarka (2007, Planet. Space Sci., 55, 598) to infer the radio emission level from the net dissipated power. We perform a set of simulations with different hydrodynamic parameters of the solar wind, IMF orientations and intensities, that allow us to calculate the dissipated power distribution and infer the existence of radio emission hot spots on the planet day side, and to calculate the integrated radio emission of the Hermean magnetosphere. Results: The obtained radio emission distribution of dissipated power is determined by the IMF orientation (associated with the reconnection regions in the magnetosphere), although the radio emission strength is dependent on the IMF intensity and solar wind hydro parameters. The calculated total radio emission level is in agreement with the one estimated in Zarka et al. (2001, Astrophys. Space Sci., 277, 293) , between 5 × 105 and 2 × 106 W.

  7. Chronic Periprosthetic Hip Joint Infection. A Retrospective, Observational Study on the Treatment Strategy and Prognosis in 130 Non-Selected Patients

    DEFF Research Database (Denmark)

    Lange, Jeppe; Troelsen, Anders; Søballe, Kjeld

    2016-01-01

    INTRODUCTION: Limited information is available regarding the treatment strategy and prognosis of non-selected patients treated for chronic periprosthetic hip joint infection. Such information is important as no head-to-head studies on treatment strategies are available. The purpose of this study...... is to report on the treatment strategy and prognosis of a non-selected, consecutive patient population. METHODS: We identified 130 patients in the National Patient Registry, consecutively treated for a chronic periprosthetic hip joint infection between 2003-2008 at 11 departments of orthopaedic surgery. We.......00001). After adjusting for selected confounders, the mortality risk was no longer significantly different. The 5-year re-infection rate after re-implantation was 14.6% (95%CI 8.0-23.1). Re-infections occurred mainly within 3 years of follow-up. The overall 1-year survival rate was 92% (95%CI 86...

  8. Technology, Empowerment and Community Radio

    OpenAIRE

    Scifo, Salvatore

    2015-01-01

    This article will provide an overview of the conceptual contours of community media and community radio, highlighting some of the key questions shaping the debate and, with the help of a case study, show how digital media in the context of community radio can help local groups to get a voice in their local media systems, and how a university-based radio station, and its students and volunteers, play an important role for a more diverse and vibrant media content available in their area.

  9. Radio Search For Extrasolar Planets

    Science.gov (United States)

    Zarka, P.

    Theoretical justification and ongoing observational efforts in view of detecting radio emissions from extrasolar planets will be presented. On the "prediction" side, a heuris- tic scaling law has been established relating the radio output of any magnetized flow- obstacle system to the incident magnetic energy flux on the obstacle. Its confirmation by the observation of radio emission from extrasolar planets would help to understand the energy budget of such a system. On the "detection" side, specific procedures have been developed for interference mitigation and weak burst detection.

  10. Advanced Radio Resource Management for Multi Antenna Packet Radio Systems

    OpenAIRE

    Stanislav Nonchev; Mikko Valkama

    2010-01-01

    In this paper, we propose fairness-oriented packet scheduling (PS) schemes with power-efficientcontrol mechanism for future packet radio systems. In general, the radio resource managementfunctionality plays an important role in new OFDMA based networks. The control of the networkresource division among the users is performed by packet scheduling functionality based on maximizingcell coverage and capacity satisfying, and certain quality of service requirements. Moreover, multiantennatransmit-r...

  11. Recent Radio Monitoring of Microquasars with RATAN-600 Radio Telescope

    CERN Document Server

    Trushkin, S A; Kotani, T; Nizhelskij, N A; Namiki, M; Tsuboi, M; Voitsik, P A

    2007-01-01

    We report about the multi-frequency (1-30 GHz) daily monitoring of the radio flux variability of the three microquasars: SS433, GRS1915+105 and Cyg X-3 during the period from September 2005 to May 2006. 1. We detected clear correlation of the flaring radio fluxes and X-rays 'spikes' at 2-12 keV emission detected in RXTE ASM from GRS1915+105 during eight relatively bright (200-600 mJy) radio flares in October 2005. The 1-22 GHz spectra of these flares in maximum were optically thick at frequencies lower 2.3 GHz and optically thin at the higher frequencies. During the radio flares the spectra of the X-ray spikes become softer than those of the quiescent phase. Thus these data indicated the transitions from very high/hard states to high/soft ones during which massive ejections are probably happened. These ejections are visible as the detected radio flares. 2. After of the quiescent radio emission we have detected a drop down of the fluxes (~20 mJy) from Cyg X-3. That is a sign of the following bright flare. Inde...

  12. Radio frequency integrated circuit design for cognitive radio systems

    CERN Document Server

    Fahim, Amr

    2015-01-01

    This book fills a disconnect in the literature between Cognitive Radio systems and a detailed account of the circuit implementation and architectures required to implement such systems.  Throughout the book, requirements and constraints imposed by cognitive radio systems are emphasized when discussing the circuit implementation details.  In addition, this book details several novel concepts that advance state-of-the-art cognitive radio systems.  This is a valuable reference for anybody with background in analog and radio frequency (RF) integrated circuit design, needing to learn more about integrated circuits requirements and implementation for cognitive radio systems. ·         Describes in detail cognitive radio systems, as well as the circuit implementation and architectures required to implement them; ·         Serves as an excellent reference to state-of-the-art wideband transceiver design; ·         Emphasizes practical requirements and constraints imposed by cognitive radi...

  13. Innovativeness and the Public Radio Audience.

    Science.gov (United States)

    Williams, Wenmouth, Jr.; Krugman, Dean M.

    1981-01-01

    A public radio audience was surveyed to test the hypothesis that a relationship exists between innovativeness and public radio listening. Rather than supporting the hypothesis, findings indicate that the entertainment and information elements of public radio are the primary attractions for the public radio audience. (MER)

  14. On the evaluation of Web Radio

    NARCIS (Netherlands)

    Field, A.N.; Hartel, Pieter H.

    We develop an evaluation method for Web radio, and perform it to see what we can be learnt about seven prominent Web radio sites. We also evaluate a commercial FM radio station for control purposes. We present a taxonomy of Web radio, and we give our observations and conclusions on this evaluation.

  15. On the evaluation of Web Radio

    NARCIS (Netherlands)

    Field, A.N.; Hartel, P.H.

    2001-01-01

    We develop an evaluation method for Web radio, and perform it to see what we can be learnt about seven prominent Web radio sites. We also evaluate a commercial FM radio station for control purposes. We present a taxonomy of Web radio, and we give our observations and conclusions on this evaluation.

  16. On the evaluation of Web Radio

    NARCIS (Netherlands)

    Field, A.N.; Hartel, Pieter H.

    2001-01-01

    We develop an evaluation method for Web radio, and perform it to see what we can be learnt about seven prominent Web radio sites. We also evaluate a commercial FM radio station for control purposes. We present a taxonomy of Web radio, and we give our observations and conclusions on this evaluation.

  17. Reconfigurable, Digital EVA Radio Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The nature of human exploration missions to the Moon and Mars demands a frequency-agile, reconfigurable, durable digital radio delivering telemetry, ranging, voice,...

  18. Reconfigurable, Digital EVA Radio Project

    Data.gov (United States)

    National Aeronautics and Space Administration — AeroAstro proposes to develop a low-power, low-volume and lightweight, state-of-the-art digital radio capable of operating in a wide variety of bands, from VHF...

  19. The Concept of 'Radio Music'

    DEFF Research Database (Denmark)

    Fjeldsøe, Michael

    2016-01-01

    In the late 1920s, young composers and musicians turned towards new fields of activity and new media in order to reach a larger audience. In Germany, this effort was part of the movement of Neue Sachlichkeit, and for a short period of time, Radiomusik was considered the ideal means for a democratic......, as discussed by Kurt Weill and Paul Hindemith, was at first greeted with great expectations, but soon a more realistic attitude prevailed. Weill, himself a radio critic as well, composed Der Lindberghflug (1929) as a piece of ‘radio music theatre’, but then changed some of its features in order to turn...... it into a didactical play for amateurs, a so-called Lehrstück. The article will present the concept of ‘radio music’ developed within German Neue Sachlichkeit and discuss the relevance of such a concept for current research in the field of radio and music....

  20. Miniaturized Digital EVA Radio Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Bennett Aerospace and Team Partners propose to develop a small, lightweight, and very power-efficient mobile radio for use on the Lunar surface. Our Team will...

  1. RADIO NOISE ADVANCES SEXUAL MATURITY

    African Journals Online (AJOL)

    ansistf-lewis

    Supplementary radio noise advances sexual maturity in domestic pullets exposed .... non-stimulatory photoperiod in some way provides a stimulus for initiating rapid gonadal development. However, the ..... Congress, New Delhi, India. Vol II ...

  2. Coherent Radio Emission from Pulsars

    CERN Document Server

    Mitra, Dipanjan; Gil, Janusz

    2015-01-01

    We review a physical model where the high brightness temperature of 10$^{25}-10^{30}$ K observed in pulsar radio emission is explained by coherent curvature radiation excited in the relativistic electron-positron plasma in the pulsar magnetosphere.

  3. SETI and International Radio Law

    Science.gov (United States)

    Lyall, F.

    2010-04-01

    The use of radio in SETI is subject to international rules agreed through the International Telecommunication Union. These are summarised. An opportunity for their revision will arise in 2012. Suggestions may be made.

  4. Radio Implementation of a Testbed For Cognitive Radio Source Localization Using USRPS and GNU Radio

    Science.gov (United States)

    2014-09-01

    pp. 116–130, 2009. [4] R.A. Rashid , M.A. Sarijari, N. Fisal, S.K.S. Yusof and N.H. Mahalin, “Spectrum sensing measurement using GNU Radio and...USRP software radio platform,” in Proc. 7th Int. Conf. Wireless and Mobile Commun., Luxembourg, 2011. [5] R.A. Rashid , M.A. Sarijari, N. Fisal...Sarijari, A. Marwanto, N. Fisal, S.K.S. Yusof and R.A Rashid , “Energy detection sensing based on GNU Radio and USRP: An analysis study,” in Proc

  5. Radio and line transmission 2

    CERN Document Server

    Roddy, Dermot

    2013-01-01

    Radio and Line Transmission, Volume 2 gives a detailed treatment of the subject as well as an introduction to additional advanced subject matter. Organized into 14 chapters, this book begins by explaining the radio wave propagation, signal frequencies, and bandwidth. Subsequent chapters describe the transmission lines and cables; the aerials; tuned and coupled circuits; bipolar transistor amplifiers; field-effect transistors and circuits; thermionic valve amplifiers; LC oscillators; the diode detectors and modulators; and the superheterodyne receiver. Other chapters explore noise and interfere

  6. Radio interferometry and satellite tracking

    CERN Document Server

    Kawase, Seiichiro

    2012-01-01

    Worldwide growth of space communications has caused a rapid increase in the number of satellites operating in geostationary orbits, causing overcrowded orbits. This practical resource is designed to help professionals overcome this problem. This timely book provides a solid understanding of the use of radio interferometers for tracking and monitoring satellites in overcrowded environments. Practitioners learn the fundamentals of radio interferometer hardware, including antennas, receiving equipment, signal processing and phase detection, and measurement accuracies. This in-depth volume describ

  7. A zero-power radio receiver.

    Energy Technology Data Exchange (ETDEWEB)

    Brocato, Robert Wesley

    2004-09-01

    This report describes both a general methodology and some specific examples of passive radio receivers. A passive radio receiver uses no direct electrical power but makes sole use of the power available in the radio spectrum. These radio receivers are suitable as low data-rate receivers or passive alerting devices for standard, high power radio receivers. Some zero-power radio architectures exhibit significant improvements in range with the addition of very low power amplifiers or signal processing electronics. These ultra-low power radios are also discussed and compared to the purely zero-power approaches.

  8. The radio properties of infrared-faint radio sources

    Science.gov (United States)

    Middelberg, E.; Norris, R. P.; Hales, C. A.; Seymour, N.; Johnston-Hollitt, M.; Huynh, M. T.; Lenc, E.; Mao, M. Y.

    2011-02-01

    Context. Infrared-faint radio sources (IFRS) are objects that have flux densities of several mJy at 1.4 GHz, but that are invisible at 3.6 μm when using sensitive Spitzer observations with μJy sensitivities. Their nature is unclear and difficult to investigate since they are only visible in the radio. Aims: High-resolution radio images and comprehensive spectral coverage can yield constraints on the emission mechanisms of IFRS and can give hints to similarities with known objects. Methods: We imaged a sample of 17 IFRS at 4.8 GHz and 8.6 GHz with the Australia Telescope Compact Array to determine the structures on arcsecond scales. We added radio data from other observing projects and from the literature to obtain broad-band radio spectra. Results: We find that the sources in our sample are either resolved out at the higher frequencies or are compact at resolutions of a few arcsec, which implies that they are smaller than a typical galaxy. The spectra of IFRS are remarkably steep, with a median spectral index of -1.4 and a prominent lack of spectral indices larger than -0.7. We also find that, given the IR non-detections, the ratio of 1.4 GHz flux density to 3.6 μm flux density is very high, and this puts them into the same regime as high-redshift radio galaxies. Conclusions: The evidence that IFRS are predominantly high-redshift sources driven by active galactic nuclei (AGN) is strong, even though not all IFRS may be caused by the same phenomenon. Compared to the rare and painstakingly collected high-redshift radio galaxies, IFRS appear to be much more abundant, but less luminous, AGN-driven galaxies at similar cosmological distances.

  9. The radio properties of infrared-faint radio sources

    CERN Document Server

    Middelberg, Enno; Hales, Christopher A; Seymour, Nick; Johnston-Hollitt, Melanie; Huynh, Minh T; Lenc, Emil; Mao, Minnie Y

    2010-01-01

    Infrared-faint radio sources (IFRS) are objects that have flux densities of several mJy at 1.4GHz, but that are invisible at 3.6um when using sensitive Spitzer observations with uJy sensitivities. Their nature is unclear and difficult to investigate since they are only visible in the radio. High-resolution radio images and comprehensive spectral coverage can yield constraints on the emission mechanisms of IFRS and can give hints to similarities with known objects. We imaged a sample of 17 IFRS at 4.8GHz and 8.6GHz with the Australia Telescope Compact Array to determine the structures on arcsecond scales. We added radio data from other observing projects and from the literature to obtain broad-band radio spectra. We find that the sources in our sample are either resolved out at the higher frequencies or are compact at resolutions of a few arcsec, which implies that they are smaller than a typical galaxy. The spectra of IFRS are remarkably steep, with a median spectral index of -1.4 and a prominent lack of spec...

  10. The Excess Radio Background and Fast Radio Transients

    CERN Document Server

    Kehayias, John; Weiler, Thomas J

    2015-01-01

    In the last few years ARCADE 2, combined with older experiments, has detected an additional radio background, measured as a temperature and ranging in frequency from 22 MHz to 10 GHz, not accounted for by known radio sources and the cosmic microwave background. One type of source which has not been considered in the radio background is that of fast transients (those with event times much less than the observing time). We present a simple estimate, and a more detailed calculation, for the contribution of radio transients to the diffuse background. As a timely example, we estimate the contribution from the recently-discovered fast radio bursts (FRBs). Although their contribution is likely 6 or 7 orders of magnitude too small (though there are large uncertainties in FRB parameters) to account for the ARCADE~2 excess, our development is general and so can be applied to any fast transient sources, discovered or yet to be discovered. We estimate parameter values necessary for transient sources to noticeably contrib...

  11. Solar Imaging Radio Array (SIRA): Radio Aperture Synthesis from Space

    Science.gov (United States)

    MacDowall, R.; Kaiser, M.; Gopalswamy, N.

    2003-05-01

    SIRA, the Solar Imaging Radio Array, will be a constellation of about 16 microsats designed to image radio sources in the solar corona and heliosphere using aperture synthesis techniques. These images will permit the mapping and tracking of CME-driven shocks (type II radio bursts) and solar flare electrons (type III radio bursts) as a function of time from near the sun to 1 AU. Two dimensional imaging of the CME-driven shock front is important for determination of space weather effects of CMEs, whereas imaging of the ubiquitous type III bursts will permit the derivation of density maps in the outer corona and solar wind. This will be the first mission to image the heliosphere (and the celestial sphere) with good angular resolution at frequencies below the ionospheric cutoff ( 10 MHz). The radio images are intrinsically complementary to white-light coronograph data, such as those of SDO, and can play a valuable role in the NASA Living with a Star program.

  12. Radio Halos in future surveys in the radio continuum

    CERN Document Server

    Cassano, R; Norris, Ray P; Roettgering, H J A; Johnston-Hollitt, M; Trasatti, M

    2012-01-01

    Giant radio halos (RH) are Mpc-scale synchrotron sources detected in a significant fraction of massive and merging galaxy clusters.Their statistical properties can be used to discriminate among various models for their origin. Theoretical predictions are important as new radio telescopes are about to begin to survey the sky at low and high frequencies with unprecedented sensitivity. We carry out Monte Carlo simulations to model the formation and evolution of RH in a cosmological framework by assuming that RH are either generated in turbulent merging clusters, or are purely hadronic sources generated in more relaxed clusters, "off-state" halos. The models predict that the luminosity function of RH at high radio luminosities is dominated by the contribution of RH generated in turbulent clusters. The generation of these RH becomes less efficient in less massive systems causing a flattening of the luminosity function at lower luminosities. This flattening is compensated by the contribution of "off-state" RH that ...

  13. IA-Regional-Radio - Social Network for Radio Recommendation

    Science.gov (United States)

    Dziczkowski, Grzegorz; Bougueroua, Lamine; Wegrzyn-Wolska, Katarzyna

    This chapter describes the functions of a system proposed for the music hit recommendation from social network data base. This system carries out the automatic collection, evaluation and rating of music reviewers and the possibility for listeners to rate musical hits and recommendations deduced from auditor's profiles in the form of regional Internet radio. First, the system searches and retrieves probable music reviews from the Internet. Subsequently, the system carries out an evaluation and rating of those reviews. From this list of music hits, the system directly allows notation from our application. Finally, the system automatically creates the record list diffused each day depending on the region, the year season, the day hours and the age of listeners. Our system uses linguistics and statistic methods for classifying music opinions and data mining techniques for recommendation part needed for recorded list creation. The principal task is the creation of popular intelligent radio adaptive on auditor's age and region - IA-Regional-Radio.

  14. Localization and cooperative communication methods for cognitive radio

    Science.gov (United States)

    Duval, Olivier

    We study localization of nearby nodes and cooperative communication for cognitive radios. Cognitive radios sensing their environment to estimate the channel gain between nodes can cooperate and adapt their transmission power to maximize the capacity of the communication between two nodes. We study the end-to-end capacity of a cooperative relaying scheme using orthogonal frequency-division modulation (OFDM) modulation, under power constraints for both the base station and the relay station. The relay uses amplify-and-forward and decode-and-forward cooperative relaying techniques to retransmit messages on a subset of the available subcarriers. The power used in the base station and the relay station transmitters is allocated to maximize the overall system capacity. The subcarrier selection and power allocation are obtained based on convex optimization formulations and an iterative algorithm. Additionally, decode-and-forward relaying schemes are allowed to pair source and relayed subcarriers to increase further the capacity of the system. The proposed techniques outperforms non-selective relaying schemes over a range of relay power budgets. Cognitive radios can be used for opportunistic access of the radio spectrum by detecting spectrum holes left unused by licensed primary users. We introduce a spectrum holes detection approach, which combines blind modulation classification, angle of arrival estimation and number of sources detection. We perform eigenspace analysis to determine the number of sources, and estimate their angles of arrival (AOA). In addition, we classify detected sources as primary or secondary users with their distinct second-orde one-conjugate cyclostationarity features. Extensive simulations carried out indicate that the proposed system identifies and locates individual sources correctly, even at -4 dB signal-to-noise ratios (SNR). In environments with a high density of scatterers, several wireless channels experience nonline-of-sight (NLOS

  15. Characterisation of PDO olive oil Chianti Classico by non-selective (UV-visible, NIR and MIR spectroscopy) and selective (fatty acid composition) analytical techniques

    Energy Technology Data Exchange (ETDEWEB)

    Casale, M., E-mail: monica@dictfa.unige.it [Universita degli Studi di Genova, Department of Chemistry and Food and Pharmaceutical Technologies, Via Brigata Salerno 13, I-16147, Genoa (Italy); Oliveri, P.; Casolino, C. [Universita degli Studi di Genova, Department of Chemistry and Food and Pharmaceutical Technologies, Via Brigata Salerno 13, I-16147, Genoa (Italy); Sinelli, N. [Universita degli Studi di Milano, Department of Food Science and Technology, Via Celoria, 2 - I-20133 Milan (Italy); Zunin, P.; Armanino, C.; Forina, M.; Lanteri, S. [Universita degli Studi di Genova, Department of Chemistry and Food and Pharmaceutical Technologies, Via Brigata Salerno 13, I-16147, Genoa (Italy)

    2012-01-27

    Highlights: Black-Right-Pointing-Pointer Characterisation of the Italian PDO extra virgin olive oil Chianti Classico. Black-Right-Pointing-Pointer Comparison between non-selective (UV-vis, NIR and MIR spectroscopy) and selective (fatty acid composition) analytical techniques. Black-Right-Pointing-Pointer Synergy among spectroscopic techniques, by the fusion of the respective spectra. Black-Right-Pointing-Pointer Prediction of the content of oleic and linoleic acids in the olive oils. - Abstract: An authentication study of the Italian PDO (protected designation of origin) extra virgin olive oil Chianti Classico was performed; UV-visible (UV-vis), Near-Infrared (NIR) and Mid-Infrared (MIR) spectroscopies were applied to a set of samples representative of the whole Chianti Classico production area. The non-selective signals (fingerprints) provided by the three spectroscopic techniques were utilised both individually and jointly, after fusion of the respective profile vectors, in order to build a model for the Chianti Classico PDO olive oil. Moreover, these results were compared with those obtained by the gas chromatographic determination of the fatty acids composition. In order to characterise the olive oils produced in the Chianti Classico PDO area, UNEQ (unequal class models) and SIMCA (soft independent modelling of class analogy) were employed both on the MIR, NIR and UV-vis spectra, individually and jointly, and on the fatty acid composition. Finally, PLS (partial least square) regression was applied on the UV-vis, NIR and MIR spectra, in order to predict the content of oleic and linoleic acids in the extra virgin olive oils. UNEQ, SIMCA and PLS were performed after selection of the relevant predictors, in order to increase the efficiency of both classification and regression models. The non-selective information obtained from UV-vis, NIR and MIR spectroscopy allowed to build reliable models for checking the authenticity of the Italian PDO extra virgin olive oil

  16. [Cost-effectiveness analysis of celecoxib versus non-selective non-steroidal anti-inflammatory drug therapy for the treatment of osteoarthritis in Spain: A current perspective].

    Science.gov (United States)

    De Lossada, A; Oteo-Álvaro, Á; Giménez, S; Oyagüez, I; Rejas, J

    2016-01-01

    To assess the cost-effectiveness of celecoxib and non-selective non-steroidal anti-inflammatory drugs for the treatment of osteoarthritis in clinical practice in Spain. A decision-tree model using distribution, doses, treatment duration and incidence of GI and CV events observed in the pragmatic PROBE-designed «GI-Reasons» trial was used for cost-effectiveness. Effectiveness was expressed in terms of event averted and quality-adjusted life-years (QALY) gained. QALY were calculated based on utility decrement in case of any adverse events reported in GI-Reasons trial. The National Health System perspective in Spain was applied; cost calculations included current prices of drugs plus cost of adverse events occurred. The analysis was expressed as an incremental cost-effectiveness ratio per QALY gained and per event averted. One-way and probabilistic analyses were performed. Compared with non-selective non-steroidal anti-inflammatory drugs, at current prices, celecoxib treatment had higher overall treatment costs €201 and €157, respectively. However, celecoxib was associated with a slight increase in QALY gain and significantly lower incidence of gastrointestinal events (pcost-effectiveness ratio of €13,286 per QALY gained and €4,471 per event averted. Sensitivity analyses were robust, and confirmed the results of the base case. Celecoxib at current price may be considered as a cost-effective alternative vs. non-selective non-steroidal anti-inflammatory drugs in the treatment of osteoarthritis in daily practice in the Spanish NHS. Copyright © 2015 Sociedad Española de Médicos de Atención Primaria (SEMERGEN). Publicado por Elsevier España, S.L.U. All rights reserved.

  17. Further evidence for differences between non-selective and BZ-1 (omega 1) selective, benzodiazepine receptor ligands in murine models of "state" and "trait" anxiety.

    Science.gov (United States)

    Griebel, G; Sanger, D J; Perrault, G

    1996-01-01

    The behavioural effects of several BZ (omega) receptor ligands were compared in mice using the light/dark choice task, an animal model of "state" anxiety, and the free-exploration test, which has been proposed as an experimental model of "trait" anxiety. The drugs used included non-selective full (alprazolam, clorazepate, chlordiazepoxide and diazepam), partial agonists (bretazenil, imidazenil and Ro 19-8022) and BZ-1 (omega 1) selective receptor ligands (abecarnil, CL 218,872 and zolpidem). In the light/dark choice task, non-selective full agonists elicited clear anxiolytic-like effects increasing time spent in the lit box and simultaneously reducing attempts at entry into the illuminated cage followed by withdrawal responses, a measure of risk assessment. With the exception of abecarnil, both non-selective partial agonists and BZ-1 (omega 1) selective receptor ligands displayed reduced efficacy compared to the full agonists as they decreased risk assessment responses without altering time in the lit box. In addition, the weak anxiolytic-like actions displayed by selective BZ-1 (omega 1) agents were evident only at doses which reduced locomotor activity, indicating that this effect may be non-specific. In the free-exploration test, non-selective BZ (omega) receptor agonists markedly increased the percentage of time spent in the novel compartment and reduced the number of attempts to enter whereas selective BZ-1 (omega 1) receptor ligands displayed a weaker neophobia-reducing effect as they reduced risk assessment responses only. As was the case in the light/dark choice task, this latter effect was observed at locomotor depressant doses. These findings indicate that while both full and partial BZ (omega) receptor agonists are equally effective against "trait" anxiety, full agonists may be superior in reducing "state" anxiety. In addition, the lack of specific effects of selective BZ-1 (omega 1) receptor ligands in reducing both types of anxiety suggests that the BZ

  18. 企业归核化战略的市场价值效应和启示--基于中国上市公司的实证分析%The Effects of Refocusing Strategy on Corporate Market Value:An Empirical Study on Listed Companies in China

    Institute of Scientific and Technical Information of China (English)

    付彦; 徐二明; 彭诚

    2015-01-01

    With the divestiture samples in China’s stock market from 2009 to 2013,it is found that the refocusing strategy can improve corporate market value continuously.Among the divestitures samples,firms with refocusing strategy have more corporate market value improvement.However,there is a U ?shaped relationship between the value effect of refocusing strategy and the pre?refocusing diversification level.%本文以2009—2013年中国上市公司剥离事件为样本,着重区分了剥离样本中实施归核化与非归核化战略的企业,对归核化的市场价值效应及其与前期多元化水平的关系进行了实证研究。结果表明:归核化战略整体上能持续提升企业市场价值;剥离样本中实施归核化比非归核化战略更能提升企业市场价值;但归核化战略的市场价值效应与前期多元化水平呈 U 型曲线关系。

  19. Reconfigurable radio systems network architectures and standards

    CERN Document Server

    Iacobucci, Maria Stella

    2013-01-01

    This timely book provides a standards-based view of the development, evolution, techniques and potential future scenarios for the deployment of reconfigurable radio systems.  After an introduction to radiomobile and radio systems deployed in the access network, the book describes cognitive radio concepts and capabilities, which are the basis for reconfigurable radio systems.  The self-organizing network features introduced in 3GPP standards are discussed and IEEE 802.22, the first standard based on cognitive radio, is described. Then the ETSI reconfigurable radio systems functional ar

  20. Unseen cosmos the universe in radio

    CERN Document Server

    Graham-Smith, Francis

    2013-01-01

    Radio telescopes have transformed our understanding of the Universe. Pulsars, quasars, Big Bang cosmology: all are discoveries of the new science of radio astronomy. Here, Francis Graham-Smith describes the birth, development, and maturity of radio astronomy, from the first discovery of cosmic radio waves to its present role as a major part of modern astronomy. Radio is part of the electromagnetic spectrum, covering infra-red, visible light, ultraviolet, X-rays, and gamma-rays, and Graham-Smith explains why it is that radio waves give us a unique view of the Universe. Tracing the development o

  1. The radio properties of bright Seyfert galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Giuricin, G.; Mardirossian, F.; Mezzetti, M.; Bertotti, G. (Centro Interuniversitario Regionale per l' Astrofisica e la Cosmologia (Italy) Centre for Advanced Research in Space Optics (Italy))

    1990-03-01

    The radio properties of a sample of 69 bright spectroscopically selected Seyfert galaxies, which suffers from little bias toward Markarian galaxies with strong UV excess. At variance with most of the earlier results, generally based on galaxy samples which are strongly biased toward the inclusion of Markarian objects, there is no clear evidence of a significant difference in the major radio properties (radio power, radio-to-optical luminosity ratio, radio spectral index and radio size) of type 1 and type 2 Seyferts. The resulting observational scenario appears now to be more consistent than before with the idea that Seyfert 2 galaxies are simply Seyfert 1 obscured objects. 70 refs.

  2. Expected Number Counts of Radio Galaxy Clusters

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Clusters of galaxies may contain radio sources if they still experience successive mergers at present. This has been confirmed by radio observations that about 30% of nearby clusters possess radio halos. We present a theoretical prediction of radio cluster counts using a semi-analytic approach which incorporates the empirical correlation between radio power and dynamical mass of clusters, and the cluster mass function described by the Press-Schechter formalism. The total population of radio clusters over the whole sky and their redshift distribution are given.

  3. Radio-Optical Imaging of ATLBS Survey

    Indian Academy of Sciences (India)

    Kshitij Thorat

    2011-12-01

    We present the radio-optical imaging of ATLBS, a sensitive radio survey (Subrahmanyan et al. 2010). The primary aim of the ATLBS survey is to image low-power radio sources which form the bulk of the radio source population to moderately high red-shifts ( ∼ 1.0). The accompanying multiband optical and near infra-red observations provide information about the hosts and environments of the radio sources. We give here details of the imaging of the radio data and optical data for the ATLBS survey.

  4. Optimization of nuclear magnetic resonance refocusing pulses to enhance signal intensity in gradient B0 field∗%优化重聚脉冲提高梯度场核磁共振信号强度*

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    It is an efficient protocol to use the refocusing flip angle pulse optimization technique to solve special engineering technical problems in nuclear magnetic resonance (NMR) measurements. By reducing RF pulse duration, the low refocusing flip angle pulses can consume lower power, satisfy specific absorption rate of samples, and improve signal-to-noise ratio as well. To further analyze the function mechanism of pulse angles, the dependence of signal intensity on RF pulse is studied in homogenous magnetic field and constant gradient magnetic field respectively. Afterwards, echo amplitudes with various tip angles and flip angles ranging from 0◦ to 180◦ are compared with conventional sequence of 90◦ pulse followed by 180◦ pulses theoretically and experimentally. For the constant gradient field, the refocusing pulse of flip angle can be as low as 140◦, defined as the optimum herein, to obtain the strongest signal intensity, enhanced by 13%compared with that of 180◦. Moreover, T1 distributions measured by the conventional and optimal sequences for distilled water at room temperature are compared, and good conformances of T1 between the two pulse sequences are obtained, which demonstrates the optimal refocusing pulse can be directly applied to T1 measurement. The results provide constructive suggestion for designing pulse sequences for signal intensity enhancement in NMR logging while drilling and NMR online quick analysis.%  缩短射频脉冲宽度,有助于解决脉冲电力消耗大、样品吸收率高、信噪比低等极端条件核磁共振探测的关键问题。本文首先分析射频脉冲角度对核磁共振自旋回波信号强度的影响机理,基于Bloch方程推导了回波信号幅度与扳转角、重聚角的关系。在特制核磁共振分析仪上采用变脉冲角度技术,分别在均匀磁场和梯度磁场条件下实现对扳转角和重聚角与回波信号强度关系的数值模拟和实验测量。结果表明,

  5. Modular Software-Defined Radio

    Directory of Open Access Journals (Sweden)

    Rhiemeier Arnd-Ragnar

    2005-01-01

    Full Text Available In view of the technical and commercial boundary conditions for software-defined radio (SDR, it is suggestive to reconsider the concept anew from an unconventional point of view. The organizational principles of signal processing (rather than the signal processing algorithms themselves are the main focus of this work on modular software-defined radio. Modularity and flexibility are just two key characteristics of the SDR environment which extend smoothly into the modeling of hardware and software. In particular, the proposed model of signal processing software includes irregular, connected, directed, acyclic graphs with random node weights and random edges. Several approaches for mapping such software to a given hardware are discussed. Taking into account previous findings as well as new results from system simulations presented here, the paper finally concludes with the utility of pipelining as a general design guideline for modular software-defined radio.

  6. A Repeating Fast Radio Burst

    CERN Document Server

    Spitler, L G; Hessels, J W T; Bogdanov, S; Brazier, A; Camilo, F; Chatterjee, S; Cordes, J M; Crawford, F; Deneva, J; Ferdman, R D; Freire, P C C; Kaspi, V M; Lazarus, P; Lynch, R; Madsen, E C; McLaughlin, M A; Patel, C; Ransom, S M; Seymour, A; Stairs, I H; Stappers, B W; van Leeuwen, J; Zhu, W W

    2016-01-01

    Fast Radio Bursts are millisecond-duration astronomical radio pulses of unknown physical origin that appear to come from extragalactic distances. Previous follow-up observations have failed to find additional bursts at the same dispersion measures (i.e. integrated column density of free electrons between source and telescope) and sky position as the original detections. The apparent non-repeating nature of the fast radio bursts has led several authors to hypothesise that they originate in cataclysmic astrophysical events. Here we report the detection of ten additional bursts from the direction of FRB121102, using the 305-m Arecibo telescope. These new bursts have dispersion measures and sky positions consistent with the original burst. This unambiguously identifies FRB121102 as repeating and demonstrates that its source survives the energetic events that cause the bursts. Additionally, the bursts from FRB121102 show a wide range of spectral shapes that appear to be predominantly intrinsic to the source and wh...

  7. Phenomenology of magnetospheric radio emissions

    Science.gov (United States)

    Carr, T. D.; Desch, M. D.; Alexander, J. K.

    1983-01-01

    Jupiter has now been observed over 24 octaves of the radio spectrum, from about 0.01 MHz to 300,000 MHz. Its radio emissions fill the entire spectral region where interplanetary electromagnetic propagation is possible at wavelengths longer than infrared. Three distinct types of radiation are responsible for this radio spectrum. Thermal emission from the atmosphere accounts for virtually all the radiation at the high frequency end. Synchrotron emission from the trapped high-energy particle belt deep within the inner magnetosphere is the dominant spectral component from about 4000 to 40 MHz. The third class of radiation consists of several distinct components of sporadic low frequency emission below 40 MHz. The decimeter wavelength emission is considered, taking into account the discovery of synchrotron emission, radiation by high-energy electrons in a magnetic field, and the present status of Jovian synchrotron phenomenology. Attention is also given to the decameter and hectometer wavelength emission, and emissions at kilometric wavelengths.

  8. An Update on Radio Supernovae

    Science.gov (United States)

    van Dyk, Schuyler D.; Sramek, Richard A.; Weiler, Kurt W.; Montes, Marcos J.; Panagia, Nino

    The radio emission from supernovae (SNe) is nonthermal synchrotron radiation of high brightness temperature, with a ``turn-on'' delay at longer wavelengths, power-law decline after maximum with index beta, and spectral index alpha asymptotically decreasing with time to a final, optically thin value. Radio supernovae (RSNe) are best described by the Chevalier (1982) ``mini-shell'' model, with modifications by Weiler \\etal\\ (1990). RSNe observations provide a valuable probe of the SN circumstellar environment and constraints on progenitor masses. We present a progress report on a number of recent RSNe, as well as on new behavior from RSNe 1979C and 1980K, and on RSNe as potential distance indicators. In particular, we present updated radio light curves for SN 1993J in M81.

  9. Radio Context Awareness and Applications

    Directory of Open Access Journals (Sweden)

    Luca Reggiani

    2013-01-01

    Full Text Available The context refers to “any information that can be used to characterize the situation of an entity, where an entity can be a person, place, or physical object.” Radio context awareness is defined as the ability of detecting and estimating a system state or parameter, either globally or concerning one of its components, in a radio system for enhancing performance at the physical, network, or application layers. In this paper, we review the fundamentals of context awareness and the recent advances in the main radio techniques that increase the context awareness and smartness, posing challenges and renewed opportunities to added-value applications in the context of the next generation of wireless networks.

  10. Miniature EVA Software Defined Radio

    Science.gov (United States)

    Pozhidaev, Aleksey

    2012-01-01

    As NASA embarks upon developing the Next-Generation Extra Vehicular Activity (EVA) Radio for deep space exploration, the demands on EVA battery life will substantially increase. The number of modes and frequency bands required will continue to grow in order to enable efficient and complex multi-mode operations including communications, navigation, and tracking applications. Whether conducting astronaut excursions, communicating to soldiers, or first responders responding to emergency hazards, NASA has developed an innovative, affordable, miniaturized, power-efficient software defined radio that offers unprecedented power-efficient flexibility. This lightweight, programmable, S-band, multi-service, frequency- agile EVA software defined radio (SDR) supports data, telemetry, voice, and both standard and high-definition video. Features include a modular design, an easily scalable architecture, and the EVA SDR allows for both stationary and mobile battery powered handheld operations. Currently, the radio is equipped with an S-band RF section. However, its scalable architecture can accommodate multiple RF sections simultaneously to cover multiple frequency bands. The EVA SDR also supports multiple network protocols. It currently implements a Hybrid Mesh Network based on the 802.11s open standard protocol. The radio targets RF channel data rates up to 20 Mbps and can be equipped with a real-time operating system (RTOS) that can be switched off for power-aware applications. The EVA SDR's modular design permits implementation of the same hardware at all Network Nodes concept. This approach assures the portability of the same software into any radio in the system. It also brings several benefits to the entire system including reducing system maintenance, system complexity, and development cost.

  11. Microwave radio transmission design guide

    CERN Document Server

    Manning, Trevor

    2009-01-01

    This newly revised second edition provides a current, comprehensive treatment of the subject with a focus on applying practical knowledge to real-world networks. It includes a wealth of important updates, including discussions on backhaul capacity limitations, ethernet over radio, details on the latest cellular radio standards (2.5G, 3G, and 4G). You also learn about recent changes in spectrum management, including the availability of unlicensed bands and new mm band frequencies between 70 and 90 GHz. Additionally, you find more details on the fundamentals of antennas, especially at VHF/UHF le

  12. Intelligent Cognitive Radio Models for Enhancing Future Radio Astronomy Observations

    Directory of Open Access Journals (Sweden)

    Ayodele Abiola Periola

    2016-01-01

    Full Text Available Radio astronomy organisations desire to optimise the terrestrial radio astronomy observations by mitigating against interference and enhancing angular resolution. Ground telescopes (GTs experience interference from intersatellite links (ISLs. Astronomy source radio signals received by GTs are analysed at the high performance computing (HPC infrastructure. Furthermore, observation limitation conditions prevent GTs from conducting radio astronomy observations all the time, thereby causing low HPC utilisation. This paper proposes mechanisms that protect GTs from ISL interference without permanent prevention of ISL data transmission and enhance angular resolution. The ISL transmits data by taking advantage of similarities in the sequence of observed astronomy sources to increase ISL connection duration. In addition, the paper proposes a mechanism that enhances angular resolution by using reconfigurable earth stations. Furthermore, the paper presents the opportunistic computing scheme (OCS to enhance HPC utilisation. OCS enables the underutilised HPC to be used to train learning algorithms of a cognitive base station. The performances of the three mechanisms are evaluated. Simulations show that the proposed mechanisms protect GTs from ISL interference, enhance angular resolution, and improve HPC utilisation.

  13. Radio access selection in multi-radio access systems

    NARCIS (Netherlands)

    Jorgušeski, L.; Litjens, R.; Zhiyi, C.; Nikookar, H.

    2007-01-01

    Future wireless access systems will be characterized by their heterogeneity from technological point of view. It is envisaged that in certain areas end-users will have a choice between various radio accesses (RAs) such as e.g. classical cellular networks (GSM, UMTS, WiMAX, etc), WLAN hot-spots, or o

  14. Cosmic downsizing of powerful radio galaxies to low radio luminosities

    CERN Document Server

    Rigby, E E; Best, P N; Rosario, D; Röttgering, H J A

    2015-01-01

    At bright radio powers ($P_{\\rm 1.4 GHz} > 10^{25}$ W/Hz) the space density of the most powerful sources peaks at higher redshift than that of their weaker counterparts. This paper establishes whether this luminosity-dependent evolution persists for sources an order of magnitude fainter than those previously studied, by measuring the steep--spectrum radio luminosity function (RLF) across the range $10^{24} 10^{26}$ W/Hz the redshift of the peak space density increases with luminosity, whilst at lower radio luminosities the position of the peak remains constant within the uncertainties. This `cosmic downsizing' behaviour is found to be similar to that seen at optical wavelengths for quasars, and is interpreted as representing the transition from radiatively efficient to inefficient accretion modes in the steep-spectrum population. This conclusion is supported by constructing simple models for the space density evolution of these two different radio galaxy classes; these are able to successfully reproduce the ...

  15. RADIO FATWA Islamic Tanya-Jawab Programmes on Radio Dakwah

    Directory of Open Access Journals (Sweden)

    Sunarwoto S.

    2012-07-01

    Full Text Available The present article is a study of radio fatwa in Indonesia with special referenceto the Tanya-Jawab genres in radio dakwah.The concept of fatwa haschanged over time. Such Islamic Tanya-Jawab programmes broadcast onradio dakwah are important to understand how fatwa is disseminated bymeans of media, since Islamic Tanya-Jawab programmes can be consideredas part of fatwa. These programmes give not only information about Islam,but also become a forum in which interpretation of Islam takes place. Thiscan be seen in the discussion on the Islamic ruling on eating “dog meat”, inwhich interpretation of Islamic law is highly contested.[Artikel ini mendisukusikan radio fatwa di Indonesia, utamanya tentangprogram tanya-jawab yang disiarkan radio dakwah. Konsep fatwa terusberubah dan program tanya-jawab merupakan salah satu cara bagaimanafatwa disebarluaskan melalui berbagai media. Penulis berpendapat bahwaprogram Tanya-Jawab dapat disebut sebagai salah satu bentuk fatwa. Inikarena program tersebut tidak saja mengetengahkan informasi mengenaiIslam, namun juga interpretasi mengenai Islam. Pedebatan mengenai hukummemakan daging anjing merupakan salah satu contoh isu kontrovesial yang akan dijelaskan melalui artikel ini.

  16. 75 FR 10439 - Cognitive Radio Technologies and Software Defined Radios

    Science.gov (United States)

    2010-03-08

    ... clarification filed by Cisco Systems, Inc. (``Cisco'') requesting that the Commission clarify: (1) The... of software that controls security measures in software defined radios. 3. In responding to the Cisco... response to the Cisco petition for reconsideration that raised the issue of using open source software...

  17. Characterisation of PDO olive oil Chianti Classico by non-selective (UV-visible, NIR and MIR spectroscopy) and selective (fatty acid composition) analytical techniques.

    Science.gov (United States)

    Casale, M; Oliveri, P; Casolino, C; Sinelli, N; Zunin, P; Armanino, C; Forina, M; Lanteri, S

    2012-01-27

    An authentication study of the Italian PDO (protected designation of origin) extra virgin olive oil Chianti Classico was performed; UV-visible (UV-vis), Near-Infrared (NIR) and Mid-Infrared (MIR) spectroscopies were applied to a set of samples representative of the whole Chianti Classico production area. The non-selective signals (fingerprints) provided by the three spectroscopic techniques were utilised both individually and jointly, after fusion of the respective profile vectors, in order to build a model for the Chianti Classico PDO olive oil. Moreover, these results were compared with those obtained by the gas chromatographic determination of the fatty acids composition. In order to characterise the olive oils produced in the Chianti Classico PDO area, UNEQ (unequal class models) and SIMCA (soft independent modelling of class analogy) were employed both on the MIR, NIR and UV-vis spectra, individually and jointly, and on the fatty acid composition. Finally, PLS (partial least square) regression was applied on the UV-vis, NIR and MIR spectra, in order to predict the content of oleic and linoleic acids in the extra virgin olive oils. UNEQ, SIMCA and PLS were performed after selection of the relevant predictors, in order to increase the efficiency of both classification and regression models. The non-selective information obtained from UV-vis, NIR and MIR spectroscopy allowed to build reliable models for checking the authenticity of the Italian PDO extra virgin olive oil Chianti Classico. Copyright © 2011 Elsevier B.V. All rights reserved.

  18. Cosmological measurements with forthcoming radio continuum surveys

    CSIR Research Space (South Africa)

    Raccanelli, A

    2012-08-01

    Full Text Available -correlation between radio sources and cosmic microwave background (CMB) maps (the integrated Sachs–Wolfe effect), the crosscorrelation of radio sources with foreground objects resulting from cosmic magnification, and a joint analysis together with the CMB power...

  19. Newnes radio and electronics engineer's pocket book

    CERN Document Server

    Moorshead, H W; Perry, J

    1978-01-01

    Newnes Radio and Electronics Engineer's Pocket Book, Fifteenth Edition provides reference of the information relevant in radio and electronics engineering. The book presents tables, illustrations, and diagrams of various data used in radio and electronics engineering. The coverage of the text includes abbreviations and symbols, electrical equations, and code conversions. The text will be useful to engineers, technicians, and other professionals who require a reference about the different aspects of radio and electronics.

  20. Sensitive Radio Survey of Obscured Quasar Candidates

    CERN Document Server

    Alexandroff, Rachael M; van Velzen, Sjoert; Greene, Jenny E; Strauss, Michael A

    2016-01-01

    We study the radio properties of moderately obscured quasars over a range of redshifts to understand the role of radio activity in accretion using the Jansky Very Large Array (JVLA) at 6.0GHz and 1.4GHz. Our z~2.5 sample consists of optically-selected obscured quasar candidates, all of which are radio-quiet, with typical radio luminosities of $\

  1. Low Frequency Radio Experiment (LORE)

    Science.gov (United States)

    Manoharan, P. K.; Naidu, Arun; Joshi, B. C.; Roy, Jayashree; Kate, G.; Pethe, Kaiwalya; Galande, Shridhar; Jamadar, Sachin; Mahajan, S. P.; Patil, R. A.

    2016-03-01

    In this paper, we present a case study of Low Frequency Radio Experiment (LORE) payload to probe the corona and the solar disturbances at solar offsets greater than 2 solar radii, i.e., at frequencies below 30 MHz. The LORE can be complimentary to the planned Indian solar mission, “Aditya-L1” and its other payloads as well as synergistic to ground-based interplanetary scintillation (IPS) observations, which are routinely carried out by the Ooty Radio Telescope. We discuss the baseline design and technical details of the proposed LORE and its particular suitability for providing measurements on the detailed time and frequency structure of fast drifting type-III and slow drifting type-II radio bursts with unprecedented time and frequency resolutions. We also brief the gonio-polarimetry, which is possible with better-designed antennas and state-of-the-art electronics, employing FPGAs and an intelligent data management system. These would enable us to make a wide range of studies, such as nonlinear plasma processes in the Sun-Earth distance, in-situ radio emission from coronal mass ejections (CMEs), interplanetary CME driven shocks, nature of ICMEs driving decelerating IP shocks and space weather effects of solar wind interaction regions.

  2. Radio properties of local AGN

    NARCIS (Netherlands)

    Nagar, NM; Falcke, H; Wilson, AS; Mujica, R; Maiolino, R

    2004-01-01

    This article focuses on the radio properties of the similar to 470 nearby bright (northern) galaxies of the Palomar spectroscopic sample. Almost half the sample's galaxies have nuclei with emission-lines characteristic of AGN but with L-H alpha = 50% of all LLAGNs; there is no evidence against all L

  3. Radio observations of massive stars

    CERN Document Server

    Blomme, Ronny

    2011-01-01

    Detectable radio emission occurs during almost all phases of massive star evolution. I will concentrate on the thermal and non-thermal continuum emission from early-type stars. The thermal radio emission is due to free-free interactions in the ionized stellar wind material. Early ideas that this would lead to an easy and straightforward way of measuring the mass-loss rates were thwarted by the presence of clumping in the stellar wind. Multi-wavelength observations provide important constraints on this clumping, but do not allow its full determination. Non-thermal radio emission is associated with binarity. This conclusion was already known for some time for Wolf-Rayet stars and in recent years it has become clear that it is also true for O-type stars. In a massive-star binary, the two stellar winds collide and around the shocks a fraction of the electrons are accelerated to relativistic speeds. Spiralling in the magnetic field these electrons emit synchrotron radiation, which we detect as non-thermal radio em...

  4. Radio emission in Mercury magnetosphere

    CERN Document Server

    Varela, J; Brun, A S; Pantellini, F; Zarka, P

    2016-01-01

    Context: Active stars possess magnetized wind that has a direct impact on planets that can lead to radio emission. Mercury is a good test case to study the effect of the solar wind and interplanetary magnetic field on radio emission driven in the planet magnetosphere. Such studies could be used as proxies to characterize the magnetic field topology and intensity of exoplanets. Aims: The aim of this study is to quantify the radio emission in the Hermean magnetosphere. Methods: We use the MHD code PLUTO in spherical coordinates with an axisymmetric multipolar expansion for the Hermean magnetic field, to analyze the effect of the interplanetary magnetic field (IMF) orientation and intensity, as well as the hydrodynamic parameters of the solar wind (velocity, density and temperature), on the net power dissipated on the Hermean day and night side. We apply the formalism derived by Zarka [2001, 2007] to infer the radio emission level from the net dissipated power. We perform a set of simulations with different hydr...

  5. Radio frequency propagation made easy

    CERN Document Server

    Faruque, Saleh

    2015-01-01

    This book introduces Radio Frequency Propagation to a broad audience.  The author blends theory and practice to bring readers up-to-date in key concepts, underlying principles and practical applications of wireless communications.  The presentation is designed to be easily accessible, minimizing mathematics and maximizing visuals.

  6. Radio Frequency Solid State Amplifiers

    CERN Document Server

    Jacob, J

    2015-01-01

    Solid state amplifiers are being increasingly used instead of electronic vacuum tubes to feed accelerating cavities with radio frequency power in the 100 kW range. Power is obtained from the combination of hundreds of transistor amplifier modules. This paper summarizes a one hour lecture on solid state amplifiers for accelerator applications.

  7. LEP radio-frequency cavity

    CERN Multimedia

    1991-01-01

    One of the copper radio-frequency accelerating cavities installed for the first phase of LEP (1989-1995). Bunches of electrons and positrons circulated in LEP in opposite directions and were accelerated in eight different sets of 16 cavities (situated on either side of the four experiments), gaining 400 million volts of accelerating power per turn.

  8. Utrecht and Galactic Radio Astronomy

    NARCIS (Netherlands)

    van Woerden, H.

    Important roles in early Dutch Galactic radio astronomy were played by several Utrecht astronomers: Van de Hulst, Minnaert and Houtgast. The poster announcing the conference contained a number of pictures referring to scientific achievements of the Astronomical Institute Utrecht. One of these

  9. The Highest Redshift Radio Galaxies

    CERN Document Server

    Van Breugel, W

    2000-01-01

    At low redshifts powerful radio sources are uniquely associated with massive galaxies, and are thought to be powered by supermassive black holes. Modern 8m -- 10m telescopes may be used used to find their likely progenitors at very high redshifts to study their formation and evolution.

  10. Young Radio Amateurs Speak English.

    Science.gov (United States)

    Freund, Bilha

    1997-01-01

    In an Israeli elementary school program to stimulate students' development of oral English skills, students write dialogs and conversation themes in areas of interest, then practice and conduct the conversations with amateur radio operators around the world. Challenges and successes are detailed. (MSE)

  11. Public safety and cognitive radio

    NARCIS (Netherlands)

    Heskamp, Marnix; Schiphorst, Roel; Slump, Kees; Wyglinsk, Alexander M.; Nekovee, Maziar; Hou, Y. Thomas

    2009-01-01

    This book gives comprehensive and balanced coverage of the principles of cognitive radio communications, cognitive networks, and details of their implementation, including the latest developments in the standards and spectrum policy. Case studies, end-of-chapter questions, and descriptions of variou

  12. Radio Monitoring of Protoplanetary Discs

    Science.gov (United States)

    Ubach, C.; Maddison, S. T.; Wright, C. M.; Wilner, D. J.; Lommen, D. J. P.; Koribalski, B.

    2017-01-01

    Protoplanetary disc systems observed at radio wavelengths often show excess emission above that expected from a simple extrapolation of thermal dust emission observed at short millimetre wavelengths. Monitoring the emission at radio wavelengths can be used to help disentangle the physical mechanisms responsible for this excess, including free-free emission from a wind or jet, and chromospheric emission associated with stellar activity. We present new results from a radio monitoring survey conducted with Australia Telescope Compact Array over the course of several years with observation intervals spanning days, months and years, where the flux variability of 11 T Tauri stars in the Chamaeleon and Lupus star forming regions was measured at 7 and 15 mm and 3 and 6 cm. Results show that for most sources are variable to some degree at 7 mm, indicating the presence of emission mechanisms other than thermal dust in some sources. Additionally, evidence of grain growth to cm-sized pebbles was found for some sources that also have signs of variable flux at 7 mm. We conclude that multiple processes contributing to the emission are common in T Tauri stars at 7 mm and beyond, and that a detection at a single epoch at radio wavelengths should not be used to determine all processes contributing to the emission.

  13. Radio frequency modulation made easy

    CERN Document Server

    Faruque, Saleh

    2017-01-01

    This book introduces Radio Frequency Modulation to a broad audience. The author blends theory and practice to bring readers up-to-date in key concepts, underlying principles and practical applications of wireless communications. The presentation is designed to be easily accessible, minimizing mathematics and maximizing visuals.

  14. China's Largest Radio Antenna System

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    @@ After three-and-half-year efforts, the National Astronomical Observatories at CAS (NAOC) has constructed two arrays of radio antennae: a 50m antenna at Miyun Station in Beijing and a 40m antenna in Kunming, capital of southwest China's Yunnan Province.

  15. Hybrid spread spectrum radio system

    Science.gov (United States)

    Smith, Stephen F [London, TN; Dress, William B [Camas, WA

    2010-02-09

    Systems and methods are described for hybrid spread spectrum radio systems. A method, includes receiving a hybrid spread spectrum signal including: fast frequency hopping demodulating and direct sequence demodulating a direct sequence spread spectrum signal, wherein multiple frequency hops occur within a single data-bit time and each bit is represented by chip transmissions at multiple frequencies.

  16. Constraining Radio Emission from Magnetars

    NARCIS (Netherlands)

    Lazarus, P.; Kaspi, V.M.; Champion, D.; Hessels, J.W.T.; Dib, R.

    2012-01-01

    We report on radio observations of five magnetars and two magnetar candidates carried out at 1950 MHz with the Green Bank Telescope in 2006-2007. The data from these observations were searched for periodic emission and bright single pulses. Also, monitoring observations of magnetar 4U 0142+61 follow

  17. Radio Properties of Pinwheel Nebulae

    CERN Document Server

    Monnier, J D; Tuthill, P G; Danchi, W C

    2002-01-01

    A small number of dusty Wolf-Rayet stars have been resolved into pinwheel nebulae, defined by their ``rotating'' spiral dust shells observed in the infrared. This morphology is naturally explained by dust formation associated with colliding winds in a binary system. In order to confirm and further explore this hypothesis, we have observed the known pinwheel nebulae (WR 104 and WR 98a) as well as the suspected binary WR 112 at multiple radio wavelengths with the Very Large Array to search for non-thermal radio emission from colliding winds. The spectrum of each target is nearly flat between 5 and 22 GHz, consistent with the presence of non-thermal emission that is reduced at low frequencies by free-free absorption. This emission must lie outside the radio ``photosphere,'' leading us to estimate a lower limit to the physical size of the non-thermal emitting region that is larger than expected from current theory. Based on a radio and infrared comparison to WR 104 and 98a, we conclude that WR 112 is a likely can...

  18. 47 CFR 90.185 - Multiple licensing of radio transmitting equipment in the mobile radio service.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Multiple licensing of radio transmitting equipment in the mobile radio service. 90.185 Section 90.185 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PRIVATE LAND MOBILE RADIO SERVICES...

  19. 62. The Return of Educational Radio?

    Science.gov (United States)

    Berman, Sally D.

    2008-01-01

    This paper examines one of the traditional technologies of distance education, radio, and presents examples of educational and community radio usage in Asia and Africa. Instead of merely transposing western approaches to distance education in developing countries, it is suggested that the developed world can learn from uses of radio in developing…

  20. Radio Broadcasting and Public Education in Africa.

    Science.gov (United States)

    Perraton, Hilary

    1981-01-01

    The strengths and weaknesses of radio for distance learning in the Third World are determined through an examination of its use for upgrading teachers, to support education and development broadly, for mass education through radio campaigns, and through the radio schools of Latin America. Eighteen references are listed. (CHC)

  1. Radio labeling with pre-assigned frequencies

    NARCIS (Netherlands)

    Bodlaender, H.L.; Broersma, H.J.; Fomin, F.V.; Pyatkin, A.V.; Woeginer, G.J.

    2007-01-01

    A radio labeling of a graph G is an assignment of pairwise distinct, positive integer labels to the vertices of G such that labels of adjacent vertices differ by at least 2. The radio labeling problem (RL) consists in determining a radio labeling that minimizes the maximum label that is used (the so

  2. Classic Radio Theatre in Contemporary Education.

    Science.gov (United States)

    West, Keith

    Radio theater production has been a component of secondary and post-secondary education since the late 1920s. Since the reduction in radio theater in the 1950s, such courses have been used to prepare students for other fields--television, film, etc. Radio theater production can be approached in two ways: classic production and modern production.…

  3. Fast radio flashes observed with LOFAR prototypes

    NARCIS (Netherlands)

    Nigl, A.

    2008-01-01

    This thesis consists of a detailed analysis of several observations with prototype stations of the Low Frequency Array (LOFAR). Chapter 1 introduces the field of radio astronomy, briefly describes the radio telescopes which were used and discusses radio frequency interference (RFI) and important too

  4. New trends in meteor radio receivers

    Science.gov (United States)

    Rault, Jean-Louis

    2014-01-01

    Recent progresses in low cost—but performing—SDR (software defined radio) technology presents a major breakthrough in the domain of meteor radio observations. Their performances are now good enough for meteor work and should therefore encourage newcomers to join the meteor radio community.

  5. 78 FR 23150 - Commercial Radio Operators

    Science.gov (United States)

    2013-04-18

    ... COMMISSION 47 CFR Parts 0, 1, 13, 80 and 87 Commercial Radio Operators AGENCY: Federal Communications Commission. ACTION: Final rule. SUMMARY: This document amends our rules concerning commercial radio operator... hold an appropriate commercial radio operator license. The Commission initiated this proceeding...

  6. 46 CFR 169.715 - Radio.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Radio. 169.715 Section 169.715 Shipping COAST GUARD..., Miscellaneous Systems, and Equipment § 169.715 Radio. (a) Radiotelegraph and radiotelephone installations are... Regulations, part 83. (b) A valid certificate issued by the FCC is evidence that the radio installation is...

  7. Radio labeling with pre-assigned frequencies

    NARCIS (Netherlands)

    Bodlaender, H.L.; Broersma, H.J.; Fomin, F.V.; Pyatkin, A.V.; Woeginer, G.J.

    2002-01-01

    A radio labeling of a graph G is an assignment of pairwise distinct, positive integer labels to the vertices of G such that labels of adjacent vertices differ by at least 2. The radio labeling problem (RL) consists in determining a radio labeling that minimizes the maximum label that is used (the

  8. Radio labeling with pre-assigned frequencies

    NARCIS (Netherlands)

    Bodlaender, H.L.; Broersma, Haitze J.; Fomin, F.V.; Pyatkin, A.V.; Woeginger, Gerhard

    2002-01-01

    A radio labeling of a graph $G$ is an assignment of pairwise distinct, positive integer labels to the vertices of $G$ such that labels of adjacent vertices differ by at least $2$. The radio labeling problem (\\mbox{\\sc RL}) consists in determining a radio labeling that minimizes the maximum label

  9. The Dynamics of Radio Galaxies and Double–Double Radio Galaxies

    Indian Academy of Sciences (India)

    C. Konar; M. Jamrozy; M. J. Hardcastle; J. H. Croston; S. Nandi; D. J. Saikia; J. Machalski

    2011-12-01

    Relativistic and magnetized plasma ejected by radio loud AGNs through jets form the diffuse lobes of radio galaxies. The radiating particles (electron/electron–positron) in lobes emit in radio via the synchrotron process and X-ray via inverse-Compton scattering of cosmic microwave background photons. The thermal environment around radio galaxies emits X-rays via the thermal bremsstrahlung process. By combining information from these processes we can measure physical conditions in and around the radio lobes and thus study the dynamics of radio galaxies, including double–double radio galaxies.

  10. Radio responding media. Prosumers, media innovation in web-based radio

    OpenAIRE

    Brundu, Gabriella

    2015-01-01

    After a century of traditional broadcasting, this is the history of how the radio as a medium entered the web world, becoming web-based radios. Our case is based on an Italian web-radio, Radio Casa Bertallot, which started to make radio programmes using the possibilities of new media technology and the internet to create a platform for interacting with the users. The founder Alessio Bertallot, expressed his view on the radio production by describing the radio as, a place, as a home, a room, ...

  11. The Role of Alternative Programming in College Radio.

    Science.gov (United States)

    Sauls, Samuel J.

    College radio is quite often viewed as the true alternative to commercial radio. However, what is alternative radio and how does college radio factor into the ideal? To further understand this concept, this paper focuses on the role of alternative programming in college radio. Areas discussed include alternative radio as a non-mainstream form of…

  12. De radio en radio: el escenario radiofónico

    Directory of Open Access Journals (Sweden)

    Lic. Dulce María García Dávila

    1999-01-01

    Full Text Available Este artículo discierne sobre concepciones modernas de programación radiofónica y presenta los resultados que arrojó el estudio del escenario radiofónico de la ciudad de Maracaibo, con el uso de la técnica de la audiografía. Nos ofrece una descripción de los tipos de programación, la música, los programas informativos y de opinión, las estrategias de promoción y publicitarias más utilizadas por las emisoras de amplitud modulada en la ciudad. Este estudio forma parte de una primera etapa del proyecto de investigación titulado "Hacia un modelo de radio educativa y popular para el Occidente del país, a partir de la experiencia de Radio Fe y Alegría 850 AM".

  13. Radio Astronomy Explorer (RAE) 1 observations of terrestrial radio noise

    Science.gov (United States)

    Herman, J. R.; Caruso, J. A.

    1971-01-01

    Radio Astonomy Explorer (RAE) 1 data are analyzed to establish characteristics of HF terrestrial radio noise at an altitude of about 6000 km. Time and frequency variations in amplitude of the observed noise well above cosmic noise background are explained on the basis of temporal and spatial variations in ionospheric critical frequency coupled with those in noise source distributions. It is shown that terrestrial noise regularly breaks through the ionosphere and reaches RAE with magnitudes 15 or more db higher than cosmic noise background. Maximum terrestrial noise is observed when RAE is over the dark side of the Earth in the neighborhood of equatorial continental land masses where thunderstorms occur most frequently. The observed noise level is 30-40 db lower with RAE over oceans.

  14. Advanced Radio Resource Management for Multi Antenna Packet Radio Systems

    CERN Document Server

    Nonchev, Stanislav; 10.5121/ijwmn.2010.2201

    2010-01-01

    In this paper, we propose fairness-oriented packet scheduling (PS) schemes with power-efficient control mechanism for future packet radio systems. In general, the radio resource management functionality plays an important role in new OFDMA based networks. The control of the network resource division among the users is performed by packet scheduling functionality based on maximizing cell coverage and capacity satisfying, and certain quality of service requirements. Moreover, multiantenna transmit-receive schemes provide additional flexibility to packet scheduler functionality. In order to mitigate inter-cell and co-channel interference problems in OFDMA cellular networks soft frequency reuse with different power masks patterns is used. Stemming from the earlier enhanced proportional fair scheduler studies for single-input multiple-output (SIMO) and multiple-input multipleoutput (MIMO) systems, we extend the development of efficient packet scheduling algorithms by adding transmit power considerations in the ove...

  15. K. C. Yeh: Radio Science Editor

    Science.gov (United States)

    Advances in satellite technology and computer science have had the greatest impact on radio science in the last quarter century, according to Kung Chie Yeh, the new editor of Radio Science. Yeh, whose term began July 1 (Eos, April 12, 1983, p. 137, February 22, 1983, p. 73), is a professor in the electrical engineering department at the University of Illinois at Urbana-Champaign.An international authority on ionospheric radio physics, Yeh also is known for his work on trans-ionospheric radio wave propagation as it affects earth-space communications and satellite navigation. Hehas been studying radio science for nearly 30 years.

  16. Radio Frequency Interference Mitigation at the WSRT

    CERN Document Server

    Fridman, P A; Millenaar, R P

    2010-01-01

    The sensitivity of radio astronomical stations is often limited by man-made radio frequency interference (RFI) due to a variety of terrestrial activities. An RFI mitigation subsystem (RFIMS) based on real-time digital signalprocessing is proposed here for the Westerbork Synthesis Radio Telescope based on a powerful field programmable gate array processor. In this system the radio astronomy signals polluted by RFI are "cleaned" with the RFIMS before routine back-end correlation processing takes place. The high temporal and frequency resolution of RFIMS allows the detection and excision of RFI better than do standard radio telescope back-end configurations.

  17. Fast Radio Bursts and Radio Transients from Black Hole Batteries

    CERN Document Server

    Mingarelli, Chiara M F; Lazio, T Joseph W

    2015-01-01

    Most black holes (BHs) will absorb a neutron star (NS) companion fully intact, without tidal disruption, suggesting the pair will remain dark to telescopes. Even without tidal disruption, electromagnetic luminosity is generated from the battery phase of the binary when the BH interacts with the NS magnetic field. Originally the luminosity was expected in high-energy X-rays or gamma-rays, however we conjecture that some of the battery power is emitted in the radio bandwidth. While the luminosity and timescale are suggestive of fast radio bursts (FRBs; millisecond-scale radio transients) NS--BH coalescence rates are too low to make these a primary FRB source. Instead, we propose the transients form a FRB sub-population, distinguishable by a double peak with a precursor. The rapid ramp-up in luminosity manifests as a precursor to the burst which is $20\\%-80\\%$ as luminous, given 0.5~ms timing resolution. The main burst is from the peak luminosity before merger. The post-merger burst follows from the NS magnetic ...

  18. 47 CFR 95.201 - (R/C Rule 1) What is the Radio Control (R/C) Radio Service?

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false (R/C Rule 1) What is the Radio Control (R/C) Radio Service? 95.201 Section 95.201 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PERSONAL RADIO SERVICES Radio Control (R/C) Radio Service...

  19. Radio-quiet Fast Coronal Mass Ejections

    Science.gov (United States)

    Gopalswamy, N.; Aguilar-Rodriguez, E.; Kaiser, M. L.; Howard, R. A.

    2004-12-01

    Coronal mass ejections (CMEs) drive shocks in the interplanetary medium that produce type II radio emission. These CMEs are faster and wider on the average, than the general population of CMEs. However, when we start from fast (speed > 900 km/s) and wide (angular width > 60 degrees), more than half of them are not associated with radio bursts. In order to understand why these CMEs are radio quiet, we collected all the fast and wide (FW) CMEs detected by the Solar and Heliospheric Observatory (SOHO) mission's Large Angle and Spectrometric Coronagraph (LASCO) and isolated those without associated type II radio bursts. The radio bursts were identified in the dynamic spectra of the Radio and Plasma Wave (WAVES) Experiment on board the Wind spacecraft. We also checked the list against metric type II radio bursts reported in Solar Geophysical Data and isolated those without any radio emission. This exercise resulted in about 140 radio-quiet FW CMEs. We identified the source regions of these CMEs using the Solar Geophysical Data listings, cross-checked against the eruption regions in the SOHO/EIT movies. We explored a number of possibilities for the radio-quietness: (i) Source region being too far behind the limb, (ii) flare size, (iii) brightness of the CME, and (iv) the density of the ambient medium. We suggest that a combination of CME energy and the Alfven speed profile of the ambient medium is primarily responsible for the radio-quietness of these FW CMEs.

  20. Relic Radio Bubbles and Cluster Cooling Flows

    CERN Document Server

    De Young, D S

    2003-01-01

    Recent suggestions that buoyant radio emitting cavities in the intracluster medium can cause significant reheating of cooling flows are re-examined when the effects of the intracluster magnetic field are included. Expansion of the cavity creates a tangential magnetic field in the ICM around the radio source, and this field can suppress instabilities that mix the ICM and the radio source. The onset of instability can be delayed for ~100 million years, and calculation of the actual reheating time shows that this may not occur until about 1Gy after creation of the cavity. These results may explain why the relic radio bubbles are still intact at such late times, and it may imply that the role of radio sources in reheating the ICM should be re-examined. In addition, the existence of relic radio cavities may also imply that the particle content of radio source lobes is primarily electrons and protons rather than electrons and positrons.

  1. Propagation engineering in radio links design

    CERN Document Server

    Ghasemi, Abdollah; Ghasemi, Farshid

    2013-01-01

    Propagation Engineering in Radio Link Design covers the basic principles of radiowaves propagation in a practical manner.  This fundamental understanding enables the readers to design radio links efficiently. This book elaborates on new achievements as well as recently developed propagation models.  This is in addition to a comprehensive overview of fundamentals of propagation in various scenarios. It examines theoretical calculations, approaches and applied procedures needed for radio links design. The authors study and analysis of the main propagation phenomena and its mechanisms based on the recommendations of International Telecommunications Union, (ITU). The book has been organized in 9 chapters and examines the role of antennas and passive reflectors in radio services, propagation mechanisms related to radar, satellite, short distance, broadcasting and trans-horizon radio links, with two chapters devoted to radio noise and main  parameters of radio link design. The book presents some 278 illustration...

  2. Curved Radio Spectra of Weak Cluster Shocks

    CERN Document Server

    Kang, Hyesung

    2015-01-01

    We explore a diffusive shock acceleration (DSA) model for radio relics in which a spherical shock impinges on a magnetized cloud of fossil relativistic electrons in the cluster periphery. Such a scenario could explain uniformity of the surface brightness and spectral curvature in the integrated spectra of thin arc-like radio relics. Toward this end, we perform DSA simulations of spherical shocks with the parameters relevant for the Sausage radio relic in cluster CIZA J2242.8+5301, and calculate the ensuing radio synchrotron emission from re-accelerated electrons. The surface brightness profile of radio-emitting postshock region and the volume-integrated radio spectrum are calculated as well. We find that the observed width of the Sausage relic can be explained reasonably well by shocks with speed $u_s \\sim 3,000 \\kms$ and sonic Mach number $M_s \\sim 3$. These shocks produce curved radio spectra that steepen gradually over $(0.1-10) \

  3. KARAKTERISTIK BAHASA PENYIAR RADIO JPI FM SOLO

    Directory of Open Access Journals (Sweden)

    Muhammad Rohmadi

    2004-06-01

    Full Text Available Bahasa adalah alat komunikasi yang digunakan penyiar Radio JPI FM Solo untuk berkomunikasi dengan para pendengarnya. Bahasa penyiar radio memiliki berbagai variasi dan karakter tersendiri dibandingkan bahasa-bahasa yang digunakan dalam ranah pendidikan, pemerintahan, dan keluarga. Karakteristik ragam bahasa penyiar Radio JPI FM Solo diwarnal campur kode, alih kode, dan nuansa humor dalam siarannya. Tujuan utama penyiar Radio JPI FM Solo adalah untuk menarik simpati pendengar dan berinteraksi dengan para pendengar Radio JPI FM Solo secara kreatif. Selain itu, ragam bahasa penyiar Radio JPI FM Solo memanfatkan beberapa fungsi utama ketika berkomunikasi dengan pendengarnya. Fungsi-fungsi tersebut adalah fungsi puitik, fungsi direktif, fungsi fatis, fungsi ekspresif, dan fungsi referensial dalam siaran Radio JPI FM Solo.

  4. Radio Frequency Power Load and Associated Method

    Science.gov (United States)

    Srinivasan, V. Karthik (Inventor); Freestone, Todd M. (Inventor); Sims, William Herbert, III (Inventor)

    2014-01-01

    A radio frequency power load and associated method. A radio frequency power load apparatus may include a container with an ionized fluid therein. The apparatus may include one conductor immersed in a fluid and another conductor electrically connected to the container. A radio frequency transmission system may include a radio frequency transmitter, a radio frequency amplifier connected to the transmitter and a radio frequency power load apparatus connected to the amplifier. The apparatus may include a fluid having an ion source therein, one conductor immersed in a fluid, and another conductor electrically connected to the container. A method of dissipating power generated by a radio frequency transmission system may include constructing a waveguide with ionized fluid in a container and connecting the waveguide to an amplifier of the transmission system.

  5. Radio Recombination Lines of Hydrogen

    Indian Academy of Sciences (India)

    G. Peach

    2015-12-01

    The impact theory of spectral line broadening is used to obtain complete profiles for radio recombination lines perturbed by electron and proton impact. The collisions can be divided into two types: inelastic, where transitions take place between hydrogen levels with different principal quantum number and elastic, where the transitions are only between degenerate levels for a particular value of . The widths of the radio lines are essentially determined by inelastic electron collisions and elastic proton collisions with the emitting hydrogen atom occupying either the upper or lower levels of the line. Here, earlier work is extended to examine the contribution from proton collisions to the line width in more detail, and it is shown that the trends in the behaviour of the widths again confirm previous results.

  6. The radio-frequency quadrupole

    CERN Document Server

    Vretenar, Maurizio

    2013-01-01

    Radio-frequency quadrupole (RFQ) linear accelerators appeared on the accelerator scene in the late 1970s and have since revolutionized the domain of low-energy proton and ion acceleration. The RFQ makes the reliable production of unprecedented ion beam intensities possible within a compact radio-frequency (RF) resonator which concentrates the three main functions of the low-energy linac section: focusing, bunching and accelerating. Its sophisticated electrode structure and strict beam dynamics and RF requirements, however, impose severe constraints on the mechanical and RF layout, making the construction of RFQs particularly challenging. This lecture will introduce the main beam optics, RF and mechanical features of a RFQ emphasizing how these three aspects are interrelated and how they contribute to the final performance of the RFQ.

  7. Exploration of the Radio-Loud/Radio Quiet Dichotomy for QSO: Using Radio Morphology and 4D Eigenvector 1

    Science.gov (United States)

    Zamfir, Sebastian; Sulentic, J. W.; Marziani, P.; Dultzin, D.

    2007-12-01

    The reality of a RL/RQ Dichotomy for QSO remains an open problem. Recent studies not only provide us with contradictory results, but also display the confusion of comparing conclusions drawn on the basis of different views on "what means radio-loud"? We propose a definition of radio loudness based on three criteria (simultaneously applied): radio morphology, radio luminosity and radio-optical flux density ratio. Fanaroff-Riley II radio sources (FRIIs) are assumed to be the parent population of RL quasars, while the core dominated RL quasars are assumed to be preferentially aligned FRIIs. Orientation-unification then suggests the RQ-RL boundary is set by the least radio luminous FRII and by the lowest radio-optical ratio for an FRII. We also consider RL and RQ quasars in the context of a 4D Eigenvector 1 (4DE1) Parameter Space that is defined independently of any radio measure. Using Sloan Digital Sky Survey (SDSS) spectroscopic data for 400+ QSO (z<0.7 and brighter than psf g =17.5), coupled with FIRST and NVSS radio surveys (1.4GHz), we show that classical RL sources distribute very differently from the RQ majority of QSO.

  8. LEP Radio Frequency Copper Cavity

    CERN Multimedia

    The pulse of a particle accelerator. 128 of these radio frequency cavities were positioned around CERN's 27-kilometre LEP ring to accelerate electrons and positrons. The acceleration was produced by microwave electric oscillations at 352 MHz. The electrons and positrons were grouped into bunches, like beads on a string, and the copper sphere at the top stored the microwave energy between the passage of individual bunches. This made for valuable energy savings as it reduced the heat generated in the cavity.

  9. Very high redshift radio galaxies

    Energy Technology Data Exchange (ETDEWEB)

    van Breugel, W.J.M., LLNL

    1997-12-01

    High redshift radio galaxies (HzRGs) provide unique targets for the study of the formation and evolution of massive galaxies and galaxy clusters at very high redshifts. We discuss how efficient HzRG samples ae selected, the evidence for strong morphological evolution at near-infracd wavelengths, and for jet-induced star formation in the z = 3 800 HzRG 4C41 17

  10. The most luminous radio galaxies

    Directory of Open Access Journals (Sweden)

    Malcolm S. Longair

    2006-01-01

    Full Text Available Se discuten las propiedades de las fuentes de radio extragal acticas m as brillantes y de sus galaxias an trionas. Estas fuentes est an asociadas con las galaxias m as masivas conocidas hasta el corrimiento al rojo de al menos 2. Resultan ser una clase unica de objetos para estudiar los n ucleos gal acticos extremadamente activos y sus galaxias an trionas, y representan retos para entender la formaci on de las galaxias m as masivas.

  11. TEACHING ENGLISH LISTENING BY RADIO

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    After noting the difficulty of teaching the skill of listening in China, the paper reports on an English by radio project at the author’s university, and suggests the reasons for its success. Problems in the teaching of listening in China THE development of listening skills for non-English majors receives some emphasis in Chinese universities nowadays. More authentic British and American recorded materials are being included. But listening is

  12. Workshop on Radio Recombination Lines

    CERN Document Server

    1980-01-01

    Since their first detection 15 years ago, radio recombination lines from several elements have been observed in a wide variety of objects including HII regions, planetary nebulae, molecular clouds, the diffuse interstellar medium, and recently, other galaxies. The observations span almost the entire range from 0.1 to 100 GHz, and employ both single­ djsh and aperture synthesis techniques. The theory of radio recombination lines has also advanced strongly, to the point where it is perhaps one of the best-understood in astro­ physics. In a parallel development, it has become possible over the last decade to study these same highly-excited atoms in the laboratory; this work provides further confirmation of the theoretical framework. However there has been continuing controversy over the astrophysical interpre­ tation of radio recombination line observations, especially regarding the role of stimulated emission. A workshop was held in Ottawa on 24-25 August, 1979, bringing together many of the active scientist...

  13. The AGN content of deep radio surveys and radio emission in radio-quiet AGN. Why every astronomer should care about deep radio fields

    CERN Document Server

    Padovani, P; Miller, N; Kellermann, K I; Mainieri, V; Rosati, P; Tozzi, P; Vattakunnel, S

    2014-01-01

    We present our very recent results on the sub-mJy radio source populations at 1.4 GHz based on the Extended Chandra Deep Field South VLA survey, which reaches ~ 30 {\\mu}Jy, with details on their number counts, evolution, and luminosity functions. The sub-mJy radio sky turns out to be a complex mix of star-forming galaxies and radio-quiet AGN evolving at a similar, strong rate and declining radio-loud AGN. While the well-known flattening of the radio number counts below 1 mJy is mostly due to star-forming galaxies, these sources and AGN make up an approximately equal fraction of the sub-mJy sky. Our results shed also light on a fifty-year-old issue, namely radio emission from radio-quiet AGN, and suggest that it is closely related to star formation, at least at z ~ 1.5 - 2. The implications of our findings for future, deeper radio surveys, including those with the Square Kilometre Array, are also discussed. One of the main messages, especially to non-radio astronomers, is that radio surveys are reaching such f...

  14. Sources of the Radio Background Considered

    Energy Technology Data Exchange (ETDEWEB)

    Singal, J.; /KIPAC, Menlo Park /Stanford U.; Stawarz, L.; /KIPAC, Menlo Park /Stanford U. /Jagiellonian U., Astron. Observ.; Lawrence, A.; /Edinburgh U., Inst. Astron. /KIPAC, Menlo Park /Stanford U.; Petrosian, V.; /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Stanford U., Appl. Phys. Dept.

    2011-08-22

    We investigate possible origins of the extragalactic radio background reported by the ARCADE 2 collaboration. The surface brightness of the background is several times higher than that which would result from currently observed radio sources. We consider contributions to the background from diffuse synchrotron emission from clusters and the intergalactic medium, previously unrecognized flux from low surface brightness regions of radio sources, and faint point sources below the flux limit of existing surveys. By examining radio source counts available in the literature, we conclude that most of the radio background is produced by radio point sources that dominate at sub {mu}Jy fluxes. We show that a truly diffuse background produced by elections far from galaxies is ruled out because such energetic electrons would overproduce the observed X-ray/{gamma}-ray background through inverse Compton scattering of the other photon fields. Unrecognized flux from low surface brightness regions of extended radio sources, or moderate flux sources missed entirely by radio source count surveys, cannot explain the bulk of the observed background, but may contribute as much as 10%. We consider both radio supernovae and radio quiet quasars as candidate sources for the background, and show that both fail to produce it at the observed level because of insufficient number of objects and total flux, although radio quiet quasars contribute at the level of at least a few percent. We conclude that the most important population for production of the background is likely ordinary starforming galaxies above redshift 1 characterized by an evolving radio far-infrared correlation, which increases toward the radio loud with redshift.

  15. Design Space Decomposition for Cognitive and Software Defined Radios

    OpenAIRE

    Fayez, Almohanad Samir

    2013-01-01

    Software Defined Radios (SDRs) lend themselves to flexibility and extensibility because theydepend on software to implement radio functionality. Cognitive Engines (CEs) introduceintelligence to radio by monitoring radio performance through a set of meters and configuringthe underlying radio design by modifying its knobs. In Cognitive Radio (CR) applications,CEs intelligently monitor radio performance and reconfigure them to meet it applicationand RF channel needs. While the issue of introduci...

  16. Radio y cultura: una propuesta de radio ciudadana en Internet

    Directory of Open Access Journals (Sweden)

    Mauricio Andrés Álvarez-Moreno

    2015-01-01

    Full Text Available El presente artículo es resultado de la investigación para optar a título de magíster “La Peña Cultural: modelo de radio ciudadana en Internet”, realizada durante los años 2013 y 2014 para la Universidad de Medellín. En ella se realiza una exploración de la radio en Internet como plataforma con herramientas multimediales que podrían afianzar la formación de ciudadanía reflexiva por medio de contenidos de promoción cultural. De la misma manera, identifica, a partir de un rastreo de emisoras en Colombia, cómo esas herramientas –las redes sociales, podcasts, chats, canales de video y nuevas formas comunicativas– permiten la participación activa de los ciudadanos en su producción. Rescatar el uso de tecnologías que facilitan la comunicación, como la radio en Internet, para reconocer y recuperar el valor de la promoción cultural propia de un estado en aras de la formación de una ciudadanía reflexiva, es el acercamiento que se hizo a partir de la etnografía y la investigación aplicada y que ahora se expone en este artículo. Es la forma en que los ciudadanos podrían converger en un medio de comunicación para producir contenidos que fortalezcan su identidad cultural o, si se quiere, su visión de nación. Es la apuesta por establecer una alternativa a los ya tradicionales modelos, una guía para la comunidad interesada en promover una ciudadanía reflexiva del patrimonio cultural. Palabras clave

  17. Radio Galaxy Zoo: host galaxies and radio morphologies derived from visual inspection

    Science.gov (United States)

    Banfield, J. K.; Wong, O. I.; Willett, K. W.; Norris, R. P.; Rudnick, L.; Shabala, S. S.; Simmons, B. D.; Snyder, C.; Garon, A.; Seymour, N.; Middelberg, E.; Andernach, H.; Lintott, C. J.; Jacob, K.; Kapińska, A. D.; Mao, M. Y.; Masters, K. L.; Jarvis, M. J.; Schawinski, K.; Paget, E.; Simpson, R.; Klöckner, H.-R.; Bamford, S.; Burchell, T.; Chow, K. E.; Cotter, G.; Fortson, L.; Heywood, I.; Jones, T. W.; Kaviraj, S.; López-Sánchez, Á. R.; Maksym, W. P.; Polsterer, K.; Borden, K.; Hollow, R. P.; Whyte, L.

    2015-11-01

    We present results from the first 12 months of operation of Radio Galaxy Zoo, which upon completion will enable visual inspection of over 170 000 radio sources to determine the host galaxy of the radio emission and the radio morphology. Radio Galaxy Zoo uses 1.4 GHz radio images from both the Faint Images of the Radio Sky at Twenty Centimeters (FIRST) and the Australia Telescope Large Area Survey (ATLAS) in combination with mid-infrared images at 3.4 μm from the Wide-field Infrared Survey Explorer (WISE) and at 3.6 μm from the Spitzer Space Telescope. We present the early analysis of the WISE mid-infrared colours of the host galaxies. For images in which there is >75 per cent consensus among the Radio Galaxy Zoo cross-identifications, the project participants are as effective as the science experts at identifying the host galaxies. The majority of the identified host galaxies reside in the mid-infrared colour space dominated by elliptical galaxies, quasi-stellar objects and luminous infrared radio galaxies. We also find a distinct population of Radio Galaxy Zoo host galaxies residing in a redder mid-infrared colour space consisting of star-forming galaxies and/or dust-enhanced non-star-forming galaxies consistent with a scenario of merger-driven active galactic nuclei (AGN) formation. The completion of the full Radio Galaxy Zoo project will measure the relative populations of these hosts as a function of radio morphology and power while providing an avenue for the identification of rare and extreme radio structures. Currently, we are investigating candidates for radio galaxies with extreme morphologies, such as giant radio galaxies, late-type host galaxies with extended radio emission and hybrid morphology radio sources.

  18. Interference Cancellation System Design Using GNU Radio

    Science.gov (United States)

    2015-12-01

    ARL-TR-7546 ● DEC 2015 US Army Research Laboratory Interference Cancellation System Design Using GNU Radio by Jan Paolo...Interference Cancellation System Design Using GNU Radio by Jan Paolo Acosta Sensors and Electron Devices Directorate, ARL...Design Using GNU Radio 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Jan Paolo Acosta 5d. PROJECT NUMBER

  19. Local radio, public opinion and citizen participation

    OpenAIRE

    BUENDÍA ASTUDILLO, ALEXANDER; Doctor Educación Univ. Del Cauca; Pino Correa, Juan Carlos; Universidad del Cauca, Popayán - Cauca

    2008-01-01

    This paper shows how local radio stations that foster citizen participation and public opinion can develop into agents of social mobilization, as long they hold a broad notion of democracy. The article gives an account of the involvement that the ECCO research group (Universidad del Cauca, Colombia) has had in the project “Citizen radio: Room for democracy”, where researchers have given support to local radio stations and have sought to understand how these media conceive, assume and work tow...

  20. Radio continuum jet in NGC 7479

    OpenAIRE

    Laine, Seppo; Beck, Rainer

    2008-01-01

    The barred galaxy NGC 7479 hosts a remarkable jet-like radio continuum feature: bright, 12-kpc long in projection, and hosting an aligned magnetic field. The degree of polarization is 6%-8% along the jet, and remarkably constant, which is consistent with helical field models. The radio brightness of the jet suggests strong interaction with the ISM and hence a location near the disk plane. We observed NGC 7479 at four wavelengths with the VLA and Effelsberg radio telescopes. The equipartition ...

  1. Millisecond extragalactic radio bursts as magnetar flares

    CERN Document Server

    Popov, S B

    2013-01-01

    Properties of the population of millisecond extragalactic radio bursts discovered by Thornton et al. (2013) are in good correspondence with the hypothesis that such events are related to hyperflares of magnetars, as was proposed by us after the first observation of an extragalactic millisecond radio burst by Lorimer et al. (2007). We also point that some of multiple millisecond radio bursts from M31 discovered by Rubio-Herrera et al. (2013) also can be related to weaker magnetar bursts.

  2. "Bonne Route"...avec Radio France Internationale ("Have a Good Trip"...with Radio France Internationale).

    Science.gov (United States)

    de Saivre, Denyse

    1989-01-01

    Radio France International, the Alliance Francaise, and the Hachette publishing company have collaborated to develop an instructional radio series linking the broadcasts with published instructional materials. Considerations addressed in the program's development are discussed. (MSE)

  3. Fast Radio Bursts and Radio Transients from Black Hole Batteries

    Science.gov (United States)

    Mingarelli, Chiara; Levin, Janna; Lazio, Joseph

    2016-03-01

    Most black holes (BHs) will absorb a neutron star (NS) companion fully intact, without tidal disruption, suggesting the pair will remain dark to telescopes. Even without tidal disruption, electromagnetic (EM) luminosity is generated from the battery phase of the binary when the BH interacts with the NS magnetic field. Originally the luminosity was expected in high-energy X-rays or gamma-rays, however we conjecture that some of the battery power is emitted in the radio bandwidth. While the luminosity and timescale are suggestive of fast radio bursts (FRBs), NS-BH coalescence rates are too low to make these a primary FRB source. Instead, we propose the transients form a FRB sub-population, distinguishable by a double peak. The main burst is from the peak luminosity before merger, while the post-merger burst follows from the NS magnetic field migration to the BH, causing a shock. NS-BH pairs are desirable for ground-based gravitational wave (GW) observatories since the pair might not be detected any other way, with EM counterparts augmenting the scientific leverage beyond the GW signal. Valuably, EM signal can break degeneracies in the parameters encoded in the GW as well as probe the NS magnetic field strength, yielding insights into open problems in NS magnetic field decay.

  4. Air shower radio detection with LOPES

    Energy Technology Data Exchange (ETDEWEB)

    Bluemer, J; Apel, W D; Arteaga, J C; Badea, F; Bekk, K; Bozdog, H; Daumiller, K [Institut fuer Kernphysik, Forschungszentrum Karlsruhe (Germany); Asch, T [Inst. Prozessdatenverarbeitung und Elektronik, Forschungszentrum Karlsruhe (Germany); Auffenberg, J [Fachbereich Physik, Universitaet Wuppertal (Germany); Baehren, L; Butcher, H [ASTRON, Dwingeloo (Netherlands); Bertaina, M; Chiavassa, A [Dipartimento di Fisica Generale dell' Universita Torino (Italy); Biermann, P L [Max-Planck-Institut fuer Radioastronomie Bonn (Germany); Brancus, I M [National Institute of Physics and Nuclear Engineering, Bucharest (Romania); Brueggemann, M; Buchholz, P [Fachbereich Physik, Universitaet Siegen (Germany); Buitink, S [Department of Astrophysics, Radboud University Nijmegen (Netherlands); Cossavella, F; Souza, V de [Institut fuer Experimentelle Kernphysik, Universitaet Karlsruhe (Germany)], E-mail: Johannes.Bluemer@ik.fzk.de (and others)

    2008-07-15

    LOPES is an array of 30 radio antenna co-located with the KASCADE-Grande extensive air shower detector in Karlsruhe, Germany. It is designed as a digital radio interferometer for the detection of radio emission from extensive air showers. LOPES features high bandwidth and fast data processing. A unique asset is the concurrent operation with KASCADE-Grande. We report about the progress in understanding the radio signals measured by LOPES. In addition, the status and further perspectives of LOPES and the large scale application of this novel detection technique are sketched.

  5. GNU Based Security in Software Defined Radio

    Directory of Open Access Journals (Sweden)

    H. B. Bhadka

    2012-11-01

    Full Text Available Various new technologies are explored for radio communication toward the 21st century. Among them the technology of "software defined radio" attracts large attention. Software Defined Radio (SDR technology implements some of the functional modules of a radio system in software enabling highly flexible handsets. SDR devices may be reconfigured dynamically via the download of new software modules. Malicious or malfunctioning downloaded software present serious security risks to SDR devices and networks in which they operate. Together with the use of software downloading, future terminals will become a platform to support the deployment of yet unspecified services and applications.

  6. Radio communications with extra-terrestrial civilizations

    Science.gov (United States)

    Kotelnikov, V. A.

    1974-01-01

    Communications between civilizations within our galaxy at the present level of radio engineering is possible, although civilizations must begin to search for each other to achieve this. If an extra-terrestrial civilization possessing a technology at our level wishes to make itself known and will transmit special radio signals to do this, then it can be picked up by us at a distance of several hundreds of light years using already existing radio telescopes and specially built radio receivers. If it wishes, this civilization can also send us information without awaiting our answer.

  7. Cosmological measurements with forthcoming radio continuum surveys

    CSIR Research Space (South Africa)

    Raccanelli

    2012-08-01

    Full Text Available –819 (2012) doi:10.1111/j.1365-2966.2012.20634.x Cosmological measurements with forthcoming radio continuum surveys Alvise Raccanelli,1� Gong-Bo Zhao,1 David J. Bacon,1 Matt J. Jarvis,2,3 Will J. Percival,1 Ray P. Norris,4 Huub Ro¨ttgering,5 Filipe B. Abdalla... of Universe – radio continuum: galaxies. 1 IN T RO D U C T I O N Radio surveys for cosmology are entering a new phase with the construction of the Low Frequency Array (LOFAR) for radio �E-mail: alvise.raccanelli@port.ac.uk astronomy (Ro¨ttgering 2003...

  8. Radio systems engineering a tutorial approach

    CERN Document Server

    Santos, Héctor J De Los; Ponte, Juan

    2015-01-01

    This book is intended for readers who already have knowledge of devices and circuits for radio-frequency (RF) and microwave communication and are ready to study the systems engineering-level aspects of modern radio communications systems. The authors provide a general overview of radio systems with their components, focusing on the analog parts of the system and their non-idealities. Based on the physical functionality of the various building blocks of a modern radio system, block parameters are derived, which allows the examination of their influence on the overall system performance. The dis

  9. Radio emission of the sun and planets

    CERN Document Server

    Zheleznyakov, V V

    1970-01-01

    International Series of Monographs in Natural Philosophy, Volume 25: Radio Emission of the Sun and Planets presents the origin of the radio emission of the planets. This book examines the outstanding triumphs achieved by radio astronomy of the solar system. Comprised of 10 chapters, this volume begins with an overview of the physical conditions in the upper layers of the Sun, the Moon, and the planets. This text then examines the three characteristics of radio emission, namely, the frequency spectrum, the polarization, and the angular spectrum. Other chapters consider the measurements of the i

  10. Signal processing for cognitive radios

    CERN Document Server

    Jayaweera, Sudharman K

    2014-01-01

    This book covers power electronics, in depth, by presenting the basic principles and application details, and it can be used both as a textbook and reference book.  Introduces the specific type of CR that has gained the most research attention in recent years: the CR for Dynamic Spectrum Access (DSA). Provides signal processing solutions to each task by relating the tasks to materials covered in Part II. Specialized chapters then discuss specific signal processing algorithms required for DSA and DSS cognitive radios  

  11. Radio frequency integrated circuit design

    CERN Document Server

    Rogers, John W M

    2010-01-01

    This newly revised and expanded edition of the 2003 Artech House classic, Radio Frequency Integrated Circuit Design, serves as an up-to-date, practical reference for complete RFIC know-how. The second edition includes numerous updates, including greater coverage of CMOS PA design, RFIC design with on-chip components, and more worked examples with simulation results. By emphasizing working designs, this book practically transports you into the authors' own RFIC lab so you can fully understand the function of each design detailed in this book. Among the RFIC designs examined are RF integrated LC

  12. HF radio systems and circuits

    CERN Document Server

    Sabin, William

    1998-01-01

    A comprehensive reference for the design of high frequency communications systems and equipment. This revised edition is loaded with practical data, much of which cannot be found in other reference books. Its approach to the subject follows the needs of an engineer from system definition and performance requirements down to the individual circuit elements that make up radio transmitters and receivers. The accompanying disk contains updated software on filters, matching networks and receiver analysis. SciTech Publishing also provides many other products related to Communication Systems Design.

  13. Radio

    DEFF Research Database (Denmark)

    Buhl, Hans

    2015-01-01

    Radioen blev opfundet ad flere omgange. Teknologien kom frem kort før 1900, mens det først var omkring 1. Verdenskrig, at radioen blev opfundet som massemedium. Det skete, da en opfindsom amerikaner fandt på at sende musik ud i æteren til de unge mænd, der smuglyttede til telegrammerne mellem de ...

  14. Double-double radio galaxies : Further insights into the formation of the radio structures

    NARCIS (Netherlands)

    Brocksopp, C.; Kaiser, C.R.; Schoenmakers, A. P.; de Bruyn, A. G.

    2011-01-01

    Double-double radio galaxies (DDRGs) offer a unique opportunity for us to study multiple episodes of jet activity in large-scale radio sources. We use radio data from the Very Large Array and the literature to model two DDRGs, B1450+333 and B1834+620, in terms of their dynamical evolution. We find t

  15. Beamed radio and far infrared emission in quasars and radio galaxies

    NARCIS (Netherlands)

    Hoekstra, H; Barthel, PD; Hes, R

    1997-01-01

    Simple orientation model predictions for the radio to far infrared spectral energy distributions of radio-loud AGN are confronted with observations at various radio frequencies. This model is subsequently used to investigate 60 mu m far-infrared data. The results are supportive of the unified scheme

  16. Double-double radio galaxies: further insights into the formation of the radio structures

    NARCIS (Netherlands)

    Brocksopp, C.; Kaiser, C. R.; Schoenmakers, A. P.; de Bruyn, A. G.

    2011-01-01

    Double-double radio galaxies (DDRGs) offer a unique opportunity for us to study multiple episodes of jet activity in large-scale radio sources. We use radio data from the Very Large Array and the literature to model two DDRGs, B1450+333 and B1834+620, in terms of their dynamical evolution. We find t

  17. Beamed radio and far infrared emission in quasars and radio galaxies

    NARCIS (Netherlands)

    Hoekstra, H; Barthel, PD; Hes, R

    Simple orientation model predictions for the radio to far infrared spectral energy distributions of radio-loud AGN are confronted with observations at various radio frequencies. This model is subsequently used to investigate 60 mu m far-infrared data. The results are supportive of the unified scheme

  18. A Profile of Independent Local Radio (Commercial Radio in Great Britain).

    Science.gov (United States)

    Sidel, M. Kent

    Commercial and noncommercial radio in the United States and Great Britain have followed opposite paths of development. Unlike the United States, where commercial radio was the historical cornerstone of the broadcasting system, the Independent Local Radio (ILR) of Britain is the newcomer into an environment heavy with the heritage of the…

  19. Kothmale Community Radio Interorg Project: True Community Radio or Feel-Good Propaganda?

    Science.gov (United States)

    Harvey-Carter, Liz

    2009-01-01

    The Kothmale Community Radio and Interorg project in Sri Lanka has been hailed as an example of how a community radio initiative should function in a developing nation. However, there is some question about whether the Kothmale Community Interorg Project is a true community radio initiative that empowers local communities to access ICT services…

  20. 76 FR 70904 - Commission Organization; Practice and Procedure; Radio Broadcast Services; and Experimental Radio...

    Science.gov (United States)

    2011-11-16

    ... COMMISSION 47 CFR Parts 0, 1, 73, and 74 Commission Organization; Practice and Procedure; Radio Broadcast Services; and Experimental Radio, Auxiliary, Special Broadcast and Other Program Distributional Services... obsolete. Section 1.805 of the Commission's rules requires common carriers engaged in public radio...

  1. Radio Observations of SNR Environments

    Directory of Open Access Journals (Sweden)

    Estela M. Reynoso

    2007-01-01

    Full Text Available Se calcula que la mayor a de los remanentes de supernovas (RSNs en nuestra galaxia se encuentran muy cerca o dentro de las nubes moleculares en las que nacieron sus estrellas progenitoras. Cuando un RSN interact ua con nubes interestelares, no s olo se altera la morfolog a y la evoluci on del RSN sino que tambi en las nubes se calientan, se comprimen, se disocian, o sufren modi caciones en su qu mica. La turbulencia que se genera en las nubes moleculares puede desencadenar formaci on estelar. El estudio de la emisi on en radio en l neas at omicas y moleculares proveniente de RSNs aporta informaci on fundamental para describir el ambiente en el cual evoluciona un RSN y determinar posibles sitios de interacci on RSN-nube interestelar. La detecci on de m asers de OH en la l nea sat elite de 1720 MHz permite acotar tanto las caracter sticas del medio ambiente chocado como de la din amica del frente de choque del RSN. En este art culo presento una recopilaci on de distintos resultados obtenidos a partir de observaciones en radio en diferentes l neas espectrales y bajo distintas condiciones en direcci on a algunos RSNs y sus entornos

  2. ELF and VLF radio waves

    Science.gov (United States)

    Barr, R.; Jones, D. L.; Rodger, C. J.

    2000-11-01

    This review covers developments in ELF and VLF radio-wave propagation research over the last 50 years of the Journal of Atmospheric and Solar-Terrestrial Physics. A review of such a large field, over such a long period, cannot be fully comprehensive and the authors have therefore covered important areas which have they themselves have found interesting. The survey begins with a review of work on natural and man made sources of ELF and VLF radiation. This is followed by sections on experimental and theoretical studies of unperturbed (ambient) ELF and VLF radio propagation. Schumann resonance research, which is currently undergoing a renaissance, is then reviewed. A review of research into transient perturbations of ELF and VLF propagation follows, extending from the early work on nuclear explosions up to the current work on sprites. The review concludes with a brief summary of the VLF navigation systems of the USSR and USA, (Alpha and Omega) whose development and life-span covered most of the last 50 years.

  3. Synergy Between Radio and Optical Telescopes: Optical Followup of Extragalactic Radio Sources

    Indian Academy of Sciences (India)

    C. H. Ishwara-Chandra

    2013-06-01

    Distance measurement is a must to characterize any source in the sky. In the radio band, it is rarely possible to get distance or redshift measurements. The optical band is the most used band to get distance estimate of sources, even for those originally discovered in other bands of the electromagnetic spectrum. However, the spectroscopic redshift measurements even for fairly bright radio sample is grossly incomplete, implying un-explored discovery space. Here we discuss the scope of optical follow up of radio sources, in particular the radio loud AGNs, from the present generation radio telescopes.

  4. Kajian implementasi radio siaran digital di Indonesia [Study of digital radio broadcasting implementation in Indonesia

    Directory of Open Access Journals (Sweden)

    Amry Daulat Gultom

    2015-12-01

    Full Text Available Peraturan Menteri Komunikasi dan Informatika RI nomor 21 tahun 2009 tentang  Standar Penyiaran Digital Untuk Penyiaran Radio pada Pita VHF di Indonesia menyatakan bahwa dalam rangka mengatasi permasalahan penggunaan frekuensi VHF Band II untuk penyiaran radio FM yang tidak sesuai dengan rencana induk, serta tidak terpenuhinya permohonan untuk penggunaan kanal frekuensi dari masyarakat, maka perlu dicarikan saluran siaran alternatif dengan menggunakan sistem penyiaran radio digital standard DAB Family. Hingga saat ini belum ada perkembangan berarti terkait implementasinya, sehingga perlu dilakukan penelitian untuk mengetahui potensi radio siaran digital, kesiapan dari sisi pemerintah, operator, dan masyarakat, dan kendala yang dihadapi serta merumuskan strategi yang akan digunakan mengatasinya. Metode analisis yang digunakan adalah SWOT dan TOWS kualitatif dari data wawancara dan studi literatur. Hasil penelitian menunjukkan bahwa pihak stasiun radio sudah siap terhadap digitalisasi radio siaran, pihak pemerintah belum begitu siap karena belum adanya regulasi pendukung Permen Kominfo tentang standard radio digital, dan masyarakat juga belum siap karena kurangnya sosialisasi dan masih susah didapatkannya perangkat penerima siaran radio digital. Pengintegrasian penerima siaran radio digital pada kendaraan bermotor roda empat dan telepon genggam yang baru dapat meningkatkan keberadaan perangkat penerima siaran radio digital.*****The Minister of Communication and Information Regulation number 21 of 2009 on Digital Broadcasting Standards for VHF Band Radio Broadcasting in Indonesia stated that in order to overcome the problems of VHF Band II frequency utilization for FM radio broadcasting that is not in accordance with the master plan, as well as non-fulfillment of the request for frequency channels utilization of the society, neeed to find alternative broadcast channel by DAB Family digital radio broadcasting system. Until now there has no

  5. Correlation between radio and broad-line emissions in radio-loud quasars

    CERN Document Server

    Cao, X; Cao, Xinwu

    1999-01-01

    Radio emission is a good indicator of the jet power of radio-loud quasars, while the emission in broad-line can well represent the accretion disc radiation in quasars. We compile a sample of all sources of which the broad-line fluxes are available from 1 Jy, S4 and S5 radio source catalogues. A correlation between radio and broad-line emission for this sample of radio-loud quasars is presented, which is in favour of a close link between the accretion processes and the relativistic jets. The BL Lac objects seem to follow the statistical behaviour of the quasars, but with fainter broad-line emission.

  6. Radio-loud and radio-quiet quasars: one population, different epochs of observation

    CERN Document Server

    Blundell, Katherine

    2008-01-01

    I bring together evidence for the rapidity with which quasars' radio synchrotron lobe emission fades and for the intermittency with which jet plasma is ejected from individual quasars and radio galaxies and affirm the picture presented by Nipoti et al (2005) that the radio-loudness of quasars is a function of the epoch at which they are observed. I briefly illustrate this account with examples of successive episodes of jet activity where the axis along which jet plasma is launched appears to have precessed. A new model for the weak core radio emission from radio-quiet quasars, that is not any kind of jet ejecta, is also briefly described.

  7. Farmer participation in radio campaigns for technology adoption:

    African Journals Online (AJOL)

    Peter Berglez

    Key words: radio campaign, participation, radio production, adoption, ... from the AFRRI hybrid maize campaign in Mangochi, Malawi, Journal of ... communication action research project whose goal was to investigate how radio and modern.

  8. 76 FR 67397 - Radio Broadcasting Services; Llano, Texas

    Science.gov (United States)

    2011-11-01

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Llano, Texas AGENCY: Federal Communications Commission... 47 CFR Part 73 Radio, Radio broadcasting. Federal Communications Commission. Nazifa Sawez,...

  9. 77 FR 59882 - Radio Broadcasting Services; Tignall, GA

    Science.gov (United States)

    2012-10-01

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Tignall, GA AGENCY: Federal Communications Commission... Radio, Radio broadcasting. Federal Communications Commission. Nazifa Sawez, Assistant Chief,...

  10. 76 FR 37049 - Radio Broadcasting Services; Bastrop, LA

    Science.gov (United States)

    2011-06-24

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Bastrop, LA AGENCY: Federal Communications Commission... Subjects in 47 CFR Part 73 Radio, Radio broadcasting. Federal Communications Commission. Nazifa...

  11. 78 FR 32 - Radio Broadcasting Services; Westley, CA

    Science.gov (United States)

    2013-01-02

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Westley, CA AGENCY: Federal Communications Commission.... 8. List of Subjects in 47 CFR Part 73 Radio, Radio broadcasting. Federal Communications...

  12. 77 FR 58799 - Radio Broadcasting Services; Roaring Springs, TX

    Science.gov (United States)

    2012-09-24

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Roaring Springs, TX AGENCY: Federal Communications... 47 CFR Part 73 Radio, Radio broadcasting. Federal Communications Commission. Nazifa Sawez,...

  13. 77 FR 64758 - Radio Broadcasting Services; Randsburg, CA

    Science.gov (United States)

    2012-10-23

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Randsburg, CA AGENCY: Federal Communications... Radio, Radio broadcasting. Federal Communications Commission. Nazifa Sawez, Assistant Chief,...

  14. Mobile radio channel as a complex medium

    DEFF Research Database (Denmark)

    Matic, Dusan; Prasad, Ramjee; Kalluri, Dikshitulu K.

    2001-01-01

    Optical fibres have almost unlimited capacity, but can not the address the users desire for mobility and ubiquitous access. The synergy of these two worlds can be seen in the direction of the Radio-over-Fibre. This paper presents to the reader an introduction for the mobile radio channel - basic ...

  15. Spectrum access games for cognitive radio networks

    CSIR Research Space (South Africa)

    Masonta, MT

    2010-09-01

    Full Text Available Cognitive Radio (CR) is seen as a key enabling technology for addressing current under-utilization and inefficient use of radio frequency spectrum. The use of CR will see most of the spectrum white spaces being used opportunistically without causing...

  16. Mars' radio spectrum and the flying dust.

    NARCIS (Netherlands)

    Roos-Serote, M.; Stam, D.M.; Fender, R.P.

    2004-01-01

    Mars' radio spectrum at centimeter wavelengths is produced by thermal radiation from the surface and sub-surface. Observations at 2.8 cm made in the 1975 and 1978 show variations of its radio brightness as a function of longitude on the planet (Doherty et al. , ApJ 233, 1979). In addition, an overal

  17. Evaluating Large-Scale Interactive Radio Programmes

    Science.gov (United States)

    Potter, Charles; Naidoo, Gordon

    2009-01-01

    This article focuses on the challenges involved in conducting evaluations of interactive radio programmes in South Africa with large numbers of schools, teachers, and learners. It focuses on the role such large-scale evaluation has played during the South African radio learning programme's development stage, as well as during its subsequent…

  18. Adaptive and Distributed Beamforming for Cognitive Radio

    NARCIS (Netherlands)

    Lian, X.

    2013-01-01

    Cognitive Radio (CR) is an energy efficient technique that is capable of optimizing the premium radio resources, such as power and spectrum. In this thesis, we focus on exploiting spatial diversity for CR. We have adopted two spatial signal processing techniques, i.e., Adaptive Beamforming (ABF) and

  19. Local control of cognitive radio networks

    NARCIS (Netherlands)

    Doerr, C.; Grunwald, D.; Sicker, D.C.

    2009-01-01

    In a network deployment, a cognitive radio will have to perform two fundamental tasks. First, each cognitive radio needs to optimize its internal operation, and second, it needs to derive a configuration that will enable and optimize communication with other nodes in the network. This latter require

  20. Interactive radio: distance education in the classroom.

    Science.gov (United States)

    1988-01-01

    The Honduran Association for Socioeconomic Growth and Development (AVANCE) in conjunction with the U.S. Agency for International Development's Radio Learning Project has developed and promoted programs for radio that encourage interactive learning in Latin America. The Second Interamerican Conference on Interactive Radio was recently held in Tela, Honduras where educators and participants came to attend workshops on scriptwriting, instructional design, community support and other related topics. The participants had the opportunity to study the second generation of interactive radio. Beginning in 1973, Nicaragua began an interactive radio program written for early grade mathematics students. Currently, Honduras is marketing a mathematics program entitled, La Familia de los Numeros," or the Family of Numbers to other countries. In Bolivia, an organization called, "Fe y Alegria," or Faith and Happiness is broadcasting educational programs through the use of interactive radio. In Ecuador, testing has begun to study the viability of interactive radio for their educational system, and in Costa Rica, replication of Honduras' "Familia de los Numeros" has begun. Teachers have noted an improved grasp of subject matter and better attentiveness through the use of interactive radio programs. The programs present 30 minutes of mathematics information and 30 minutes of language information. For each grade, 170 programs have been developed.

  1. Transient pulsed radio emission from a magnetar.

    Science.gov (United States)

    Camilo, Fernando; Ransom, Scott M; Halpern, Jules P; Reynolds, John; Helfand, David J; Zimmerman, Neil; Sarkissian, John

    2006-08-24

    Anomalous X-ray pulsars (AXPs) are slowly rotating neutron stars with very bright and highly variable X-ray emission that are believed to be powered by ultra-strong magnetic fields of >10(14) G, according to the 'magnetar' model. The radio pulsations that have been observed from more than 1,700 neutron stars with weaker magnetic fields have never been detected from any of the dozen known magnetars. The X-ray pulsar XTE J1810-197 was revealed (in 2003) as the first AXP with transient emission when its luminosity increased 100-fold from the quiescent level; a coincident radio source of unknown origin was detected one year later. Here we show that XTE J1810-197 emits bright, narrow, highly linearly polarized radio pulses, observed at every rotation, thereby establishing that magnetars can be radio pulsars. There is no evidence of radio emission before the 2003 X-ray outburst (unlike ordinary pulsars, which emit radio pulses all the time), and the flux varies from day to day. The flux at all radio frequencies is approximately equal--and at >20 GHz XTE J1810-197 is currently the brightest neutron star known. These observations link magnetars to ordinary radio pulsars, rule out alternative accretion models for AXPs, and provide a new window into the coronae of magnetars.

  2. Orbiting low frequency array for radio astronomy

    NARCIS (Netherlands)

    Rajan, Rai Thilak; Rajan, Raj; Engelen, Steven; Bentum, Marinus Jan; Verhoeven, Chris

    2011-01-01

    Recently new and interesting science drivers have emerged for very low frequency radio astronomy from 0.3 MHz to 30 MHz. However Earth bound radio observations at these wavelengths are severely hampered by ionospheric distortions, man made interference, solar flares and even complete reflection belo

  3. Commercial French Radio in the Classroom.

    Science.gov (United States)

    Melpignano, Richard J.

    1980-01-01

    Describes several techniques for implementing commercial radio to improve listening comprehension skills in the foreign language student. Canadian radio, accessible to much of the northern United States, brings news, weather, and sports, in French, to the student of French and provides major components for sharpening comprehension skills. (PJM)

  4. Regulation of Wire and Radio Communication.

    Science.gov (United States)

    Federal Communications Commission, Washington, DC.

    This bulletin reviews early federal regulation of telegraphy, telephone, and radio communications, and the development of the Radio Acts of 1912 and 1927, the Communications Act of 1934, and the Communications Satellite Act of 1962. A large portion of the discussion focuses on the regulatory power and procedures of the Federal Communications…

  5. Orbiting low frequency array for radio astronomy

    NARCIS (Netherlands)

    Rajan, Rai Thilak; Engelen, Steven; Bentum, Mark; Verhoeven, Chris

    2011-01-01

    Recently new and interesting science drivers have emerged for very low frequency radio astronomy from 0.3 MHz to 30 MHz. However Earth bound radio observations at these wavelengths are severely hampered by ionospheric distortions, man made interference, solar flares and even complete reflection belo

  6. Reconfigurable Radio-Over-Fiber Networks [Invited

    DEFF Research Database (Denmark)

    Vegas Olmos, Juan José; Tafur Monroy, Idelfonso

    2015-01-01

    This paper discusses reconfigurable Radio-over-Fiber networks, including activities in coherent remote access units, silicon photonics for microwave photonics and optical switching.......This paper discusses reconfigurable Radio-over-Fiber networks, including activities in coherent remote access units, silicon photonics for microwave photonics and optical switching....

  7. Need a Classroom Stimulus? Introduce Radio Astronomy

    Science.gov (United States)

    Derman, Samuel

    2010-01-01

    Silently, invisibly, ceaselessly, our planet Earth is showered by radio waves from every direction and from every region of space. This radio energy originates in our solar system, throughout the Milky Way galaxy, and far beyond, out to the remotest reaches of the universe. Detecting and unraveling the origins of these invisible signals is what…

  8. Mars' radio spectrum and the flying dust.

    NARCIS (Netherlands)

    M. Roos-Serote; D.M. Stam; R.P. Fender

    2004-01-01

    Mars' radio spectrum at centimeter wavelengths is produced by thermal radiation from the surface and sub-surface. Observations at 2.8 cm made in the 1975 and 1978 show variations of its radio brightness as a function of longitude on the planet (Doherty et al. , ApJ 233, 1979). In addition, an overal

  9. A Radio-Controlled Car Challenge

    Science.gov (United States)

    Roman, Harry T.

    2010-01-01

    Watching a radio-controlled car zip along a sidewalk or street has become a common sight. Within this toy are the basic ingredients of a mobile robot, used by industry for a variety of important and potentially dangerous tasks. In this challenge, students consider modifying an of-the-shelf, radio-controlled car, adapting it for a robotic task.

  10. 47 CFR 32.2231 - Radio systems.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Radio systems. 32.2231 Section 32.2231 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES UNIFORM SYSTEM OF ACCOUNTS FOR TELECOMMUNICATIONS COMPANIES Instructions for Balance Sheet Accounts § 32.2231 Radio systems. (a...

  11. Towards Cognitive Radio for emergency networks

    NARCIS (Netherlands)

    Zhang, Qiwei; Hoeksema, F.W.; Kokkeler, A.B.J.; Smit, G.J.M.

    2006-01-01

    Large parts of the assigned spectrum is underutilized while the increasing number of wireless multimedia applications leads to spectrum scarcity. Cognitive Radio is an option to utilize non-used parts of the spectrum that actually are assigned to primary services. The benefits of Cognitive Radio are

  12. Antenna Construction and Propagation of Radio Waves.

    Science.gov (United States)

    Marine Corps Inst., Washington, DC.

    Developed as part of the Marine Corps Institute (MCI) correspondence training program, this course on antenna construction and propagation of radio waves is designed to provide communicators with instructions in the selection and/or construction of the proper antenna(s) for use with current field radio equipment. Introductory materials include…

  13. Basic radio interferometry for future lunar missions

    NARCIS (Netherlands)

    Aminaei, Amin; Klein Wolt, Marc; Chen, Linjie; Bronzwaer, Thomas; Pourshaghaghi, Hamid Reza; Bentum, Mark J.; Falcke, Heino

    2014-01-01

    In light of presently considered lunar missions, we investigate the feasibility of the basic radio interferometry (RIF) for lunar missions. We discuss the deployment of two-element radio interferometer on the Moon surface. With the first antenna element is envisaged to be placed on the lunar lander,

  14. The RadioSat (sm) network

    Science.gov (United States)

    Noreen, Gary K.

    1991-09-01

    The RadioSat network under development by radio Satellite Corporation will use mobile satellite (MSAT) technology to provide diverse personal communications, broadcast, and navigation services. The network will support these services simultaneously for integrated mobile radios throughout Canada and the United States. The RadioSat network takes advantage of several technological breakthroughs, all coming to fruition by the time the first MSAT satellite is launched in 1994. The most important of these breakthroughs is the enormous radiated power of each MSAT spacecraft - orders of magnitude greater than the radiated power of previous L-band spacecraft. Another important breakthrough is the development of advanced digital audio compression algorithms, enabling the transmission of broadcast quality music at moderate data rates. Finally, continuing dramatic increases in VLSI capabilities permit the production of complex, multi-function mobile satellite radios in very large quantities at prices little more than those of conventional car radios. In addition to performance breakthroughs and their economic implications to RadioSat, the design of the RadioSat network is reviewed.

  15. A review on radio based activity recognition

    Directory of Open Access Journals (Sweden)

    Shuangquan Wang

    2015-02-01

    Full Text Available Recognizing human activities in their daily living enables the development and widely usage of human-centric applications, such as health monitoring, assisted living, etc. Traditional activity recognition methods often rely on physical sensors (camera, accelerometer, gyroscope, etc. to continuously collect sensor readings, and utilize pattern recognition algorithms to identify user׳s activities at an aggregator. Though traditional activity recognition methods have been demonstrated to be effective in previous work, they raise some concerns such as privacy, energy consumption and deployment cost. In recent years, a new activity recognition approach, which takes advantage of body attenuation and/or channel fading of wireless radio, has been proposed. Compared with traditional activity recognition methods, radio based methods utilize wireless transceivers in environments as infrastructure, exploit radio communication characters to achieve high recognition accuracy, reduce energy cost and preserve user׳s privacy. In this paper, we divide radio based methods into four categories: ZigBee radio based activity recognition, WiFi radio based activity recognition, RFID radio based activity recognition, and other radio based activity recognition. Some existing work in each category is introduced and reviewed in detail. Then, we compare some representative methods to show their advantages and disadvantages. At last, we point out some future research directions of this new research topic.

  16. Software defined radio based multi-carrier multi-function waveform for cognitive radio

    Science.gov (United States)

    Zhou, Ruolin; Li, Xue; Chakravarthy, Vasu; Wu, Zhiqiang

    2010-04-01

    In this paper, we demonstrate an adaptive multicarrier multi-function waveform generator for cognitive radio via software defined radio. Using a USRP (universal software radio peripheral) software defined radio boards and GNU radio software, we implement a multi-carrier waveform generator which can generate multi-function waveforms such as OFDM, NC-OFDM, MC-CDMA, NC-MC-CDMA, CI/MC-CDMA, NCCI/ MC-CDMA, TDCS for cognitive radio. Additionally, we demonstrate a portable overlay cognitive radio using this multicarrier multi-function waveform generator. This cognitive radio is capable of detecting primary users in real time and adaptively adjusting its transmission parameters to avoid interference to primary users. More importantly, this cognitive radio can take advantage of multiple spectrum holes by employing non-contiguous multi-carrier transmission technologies. Additionally, we demonstrate that when the primary user transmission changes, the cognitive radio dynamically adjusts its transmission accordingly. We also demonstrate seamless real time video transmission between two cognitive radio nodes, while avoiding interference from primary users and interference to primary users operating in the same spectrum.

  17. Steep Spectrum Radio Sources in Galaxy Clusters

    Science.gov (United States)

    Clarke, Tracy E.

    2012-05-01

    Steep spectrum radio emission associated with galaxy clusters comes from compact central active galactic nuclei (AGN) driven radio sources in dense cool core clusters as well as from large regions of diffuse (halo and relic) emission associated with dynamically complex merging systems. These radio halos and relics are best traced at low radio frequencies where details of their morphology, location and spectral index distribution can be used to probe the underlying acceleration mechanism(s) as well as important details of large scale structure formation. Low frequency radio observations also play an important role in the study of AGN feedback into the intracluster medium and the regulation of cooling cores. While spectacular results are coming from the current generation of low frequency instruments, there will soon be a new revolution in studies of steep spectrum sources with the upcoming generation of low frequency interferometers on Earth and ultimately the moon.

  18. Optical spectroscopy of four young radio sources

    Science.gov (United States)

    Fan, Xu-Liang; Bai, Jin-Ming; Hu, Chen; Wang, Jian-Guo

    2017-01-01

    We report the optical spectroscopy of four young radio sources which are observed with the Lijiang 2.4 m telescope. The Eddington ratios of these sources are similar with those of narrow-line Seyfert 1 galaxies (NLS1s). Their Fe II emission is strong while [O III] strength is weak. These results confirm the NLS1 features of young radio sources, except that the width of broad Hβ of young radio sources is larger than that of NLS1s. We thus suggest that the young radio sources are the high black hole mass counterparts of steep-spectrum radio-loud NLS1s. In addition, the broad Hβ component of 4C 12.50 is the blue wing of the narrow component, but not from the broad line region.

  19. Optical Spectroscopy of Four Young Radio Sources

    CERN Document Server

    Fan, Xu-Liang; Hu, Chen; Wang, Jian-Guo

    2016-01-01

    We report the optical spectroscopy of four young radio sources which are observed with the Lijiang 2.4m telescope. The Eddington ratios of these sources are similar with those of narrow-line Seyfert 1 galaxies (NLS1s). Their Fe {\\sc ii} emission is strong while [O {\\sc iii}] strength is weak. These results confirm the NLS1 features of young radio sources, except that the width of broad H$\\beta$ of young radio sources is larger than that of NLS1s. We thus suggest that the young radio sources are the high black hole mass counterparts of steep-spectrum radio-loud NLS1s. In addition, the broad H$\\beta$ component of \\astrobj{4C 12.50} is the blue wing of the narrow component, but not from the broad line region.

  20. Radio Wavelength Transients: Current and Emerging Prospects

    CERN Document Server

    Lazio, J

    2008-01-01

    Known classes of radio wavelength transients range from the nearby--stellar flares and radio pulsars--to the distant Universe--\\gamma-ray burst afterglows. Hypothesized classes of radio transients include analogs of known objects, e.g., extrasolar planets emitting Jovian-like radio bursts and giant-pulse emitting pulsars in other galaxies, to the exotic, prompt emission from \\gamma-ray bursts, evaporating black holes, and transmitters from other civilizations. A number of instruments and facilities are either under construction or in early observational stages and are slated to become available in the next few years. With a combination of wide fields of view and wavelength agility, the detection and study of radio transients will improve immensely.

  1. On Achievable Performance of Cognitive Radio Systems

    CERN Document Server

    Haddad, Majed; Hayar, Aawatif Menouni

    2007-01-01

    In this contribution, we investigate the idea of using cognitive radio to reuse locally unused spectrum to increase the total system capacity. We consider a multiband/wideband system in which the primary and cognitive users wish to communicate to different receivers, subject to mutual interference and assume that each user knows only his channel and the unused spectrum through adequate sensing. Under this scheme, a cognitive radio will listen to the channel and, if sensed idle, will transmit during the voids. Within this setting, we provide two simple methods for sensing the idle sub-bands over the total bandwidth. We impose the constraint that users successively transmit over available bands through proper water filling. For the first time, our study has quantified the achievable gain of using cognitive radio with respect to classical radio devices and derive the total spectral efficiency as well as the maximum number of possible pairwise communications of such a cognitive radio system. We finally show that ...

  2. A mechanism for fast radio bursts

    CERN Document Server

    Romero, Gustavo E; Vieyro, Florencia L

    2015-01-01

    Fast radio bursts are mysterious transient sources likely located at cosmological distances. The derived brightness temperatures exceed by many orders of magnitude the self-absorption limit of incoherent synchrotron radiation, implying the operation of a coherent emission process. We propose a radiation mechanism for fast radio bursts where the emission arises from collisionless Bremsstrahlung in strong plasma turbulence excited by relativistic electron beams. We discuss possible astrophysical scenarios in which this process might operate. The emitting region is a turbulent plasma hit by a relativistic jet, where Langmuir plasma waves produce a concentration of intense electrostatic soliton-like regions (cavitons). The resulting radiation is coherent and, under some physical conditions, can be polarised and have a power-law distribution in energy. We obtain radio luminosities in agreement with the inferred values for fast radio bursts. The timescale of the radio flare in some cases can be extremely fast, of t...

  3. Giant radio galaxies and cosmic web

    Science.gov (United States)

    Heinämäki, Pekka

    2016-10-01

    Giant radio galaxies create the welldistinguishable class of sources.These sources are characterized with edge-brightened radio lobes withhighly collimated radio jets and large linear sizes which make themthe largest individual structures in the Universe. They are also knownto be hosted by elliptical/disturbed host galaxies and avoid clustersand high galaxy density regions. Because of GRG, large linear sizeslobes extend well beyond the interstellar media and host galaxyhalo the evolution of the radio lobes may depend on interactionwith this environment. Using our method to extract filamentarystructure of the galaxies in our local universe we study whetherradio lobe properties in some giant radio galaxies are determinedon an interaction of this filament ambient.

  4. Statistical properties of extragalactic radio sources

    Institute of Scientific and Technical Information of China (English)

    Zhang Jiang-Shui

    2004-01-01

    In this paper, a large sample of extragalactic radio sources is analysed to show their statistical properties. The core and total radio powers are used to determine the core-dominance parameter for galaxies, BL Lacertae objects and quasars; mutual correlations between core radio power, total radio power, redshift and core dominance parameter are 0examined for different subclasses. A statistically significant correlation between the total and core radio power is confirmed. There are no obvious correlations between core-dominance parameter and the total power for our whole sample and quasars, but there is a statistically significant anti-correlation for our galaxy sample. Some discussions and comparison of the correlations with those obtained by other authors are also given.

  5. The crisis of the radio producing

    Directory of Open Access Journals (Sweden)

    Dr. Raúl Garcés

    2007-09-01

    Full Text Available In a media world highly influenced by new technologies revolution and the increasing impact of television, speeches on radio are frequently polarized: in one side, some scholars argue radio belongs to the past and it is no longer able of attracting younger audiences. In the other, lay those who predict long life to radio as a source of alternative and communitarian communication experiences. The author reviews the arguments that sustain both perspectives and emphasizes the need of renovating radio producing with audacious and creative formulas. At the same time, he discusses some of the challenges Cuban radio has ahead to attract new audiences, when television and printed press are recovering from the economic crack the Island suffered after Eastern European socialism disappeared.

  6. Cognitive Radio RF: Overview and Challenges

    Directory of Open Access Journals (Sweden)

    Van Tam Nguyen

    2012-01-01

    Full Text Available Cognitive radio system (CRS is a radio system which is aware of its operational and geographical environment, established policies, and its internal state. It is able to dynamically and autonomously adapt its operational parameters and protocols and to learn from its previous experience. Based on software-defined radio (SDR, CRS provides additional flexibility and offers improved efficiency to overall spectrum use. CRS is a disruptive technology targeting very high spectral efficiency. This paper presents an overview and challenges of CRS with focus on radio frequency (RF section. We summarize the status of the related regulation and standardization activities which are very important for the success of any emerging technology. We point out some key research challenges, especially implementation challenges of cognitive radio (CR. A particular focus is on RF front-end, transceiver, and analog-to-digital and digital-to-analog interfaces which are still a key bottleneck in CRS development.

  7. Infrared imaging of WENSS radio sources

    CERN Document Server

    Villani, D

    1999-01-01

    We have performed deep imaging in the IR J- and K-bands for three sub-samples of radio sources extracted from the Westerbork Northern Sky Survey, a large low-frequency radio survey containing Ultra Steep Spectrum (USS), Gigahertz Peaked Spectrum (GPS) and Flat Spectrum (FS) sources. We present the results of these IR observations, carried out with the ARcetri Near Infrared CAmera (ARNICA) at the Nordic Optical Telescope (NOT), providing photometric and morphologic information on high redshift radio galaxies and quasars. We find that the radio galaxies contained in our sample do not show the pronounced radio/IR alignment claimed for 3CR sources. IR photometric measurements of the gravitational lens system 1600+434 are also presented.

  8. Planck early results: Spectral energy distributions and radio continuum spectra of northern extragalactic radio sources

    CERN Document Server

    Aatrokoski, J; Aghanim, N; Aller, H D; Aller, M F; Angelakis, E; Arnaud, M; Ashdown, M; Aumont, J; Baccigalupi, C; Balbi, A; Banday, A J; Barreiro, R B; Bartlett, J G; Battaner, E; Benabed, K; Benoît, A; Berdyugin, A; Bernard, J -P; Bersanelli, M; Bhatia, R; Bonaldi, A; Bonavera, L; Bond, J R; Borrill, J; Bouchet, F R; Bucher, M; Burigana, C; Burrows, D N; Cabella, P; Capalbi, M; Cappellini, B; Cardoso, J -F; Catalano, A; Cavazzuti, E; Cayón, L; Challinor, A; Chamballu, A; Chary, R -R; Chiang, L -Y; Christensen, P R; Clements, D L; Colafrancesco, S; Colombi, S; Couchot, F; Coulais, A; Cutini, S; Cuttaia, F; Danese, L; Davies, R D; Davis, R J; de Bernardis, P; de Gasperis, G; de Rosa, A; de Zotti, G; Delabrouille, J; Delouis, J -M; Dickinson, C; Dole, H; Donzelli, S; Doré, O; Dörl, U; Douspis, M; Dupac, X; Efstathiou, G; Enßlin, T A; Finelli, F; Forni, O; Frailis, M; Franceschi, E; Fuhrmann, L; Galeotta, S; Ganga, K; Gargano, F; Gasparrini, D; Gehrels, N; Giard, M; Giardino, G; Giglietto, N; Giommi, P; Giordano, F; Giraud-Héraud, Y; González-Nuevo, J; Górski, K M; Gratton, S; Gregorio, A; Gruppuso, A; Harrison, D; Henrot-Versillé, S; Herranz, D; Hildebrandt, S R; Hivon, E; Hobson, M; Holmes, W A; Hovest, W; Hoyland, R J; Huffenberger, K M; Jaffe, A H; Juvela, M; Keihänen, E; Keskitalo, R; King, O; Kisner, T S; Kneissl, R; Knox, L; Krichbaum, T P; Kurki-Suonio, H; Lagache, G; Lähteenmäki, A; Lamarre, J -M; Lasenby, A; Laureijs, R J; Lavonen, N; Lawrence, C R; Leach, S; Leonardi, R; León-Tavares, J; Linden-V\\ornle, M; Lindfors, E; López-Caniego, M; Lubin, P M; Macías-Pérez, J F; Maffei, B; Maino, D; Mandolesi, N; Mann, R; Maris, M; Martínez-González, E; Masi, S; Massardi, M; Matarrese, S; Matthai, F; Max-Moerbeck, W; Mazziotta, M N; Mazzotta, P; Melchiorri, A; Mendes, L; Mennella, A; Michelson, P F; Mingaliev, M; Mitra, S; Miville-Deschênes, M -A; Moneti, A; Monte, C; Montier, L; Morgante, G; Mortlock, D; Munshi, D; Murphy, A; Naselsky, P; Natoli, P; Nestoras, I; Netterfield, C B; Nieppola, E; Nilsson, K; N\\orgaard-Nielsen, H U; Noviello, F; Novikov, D; Novikov, I; O'Dwyer, I J; Osborne, S; Pajot, F; Partridge, B; Pasian, F; Patanchon, G; Pavlidou, V; Pearson, T J; Perdereau, O; Perotto, L; Perri, M; Perrotta, F; Piacentini, F; Piat, M; Plaszczynski, S; Platania, P; Pointecouteau, E; Polenta, G; Ponthieu, N; Poutanen, T; Prézeau, G; Prunet, S; Puget, J -L; Rachen, J P; Rainó, S; Reach, W T; Readhead, A; Rebolo, R; Reeves, R; Reinecke, M; Reinthal, R; Renault, C; Ricciardi, S; Richards, J; Riller, T; Riquelme, D; Ristorcelli, I; Rocha, G; Rosset, C; Rowan-Robinson, M; Rubi\; Rusholme, B; Saarinen, J; Sandri, M; Savolainen, P; Scott, D; Seiffert, M D; Sievers, A; Sillanpää, A; Smoot, G F; Sotnikova, Y; Starck, J -L; Stevenson, M; Stivoli, F; Stolyarov, V; Sudiwala, R; Sygnet, J -F; Takalo, L; Tammi, J; Tauber, J A; Terenzi, L; Thompson, D J; Toffolatti, L; Tomasi, M; Tornikoski, M; Torre, J -P; Tosti, G; Tramacere, A; Tristram, M; Tuovinen, J; Türler, M; Turunen, M; Umana, G; Ungerechts, H; Valenziano, L; Valtaoja, E; Varis, J; Verrecchia, F; Vielva, P; Villa, F; Vittorio, N; Wandelt, B D; Wu, J; Yvon, D; Zacchei, A; Zensus, J A; Zhou, X; Zonca, A

    2011-01-01

    Spectral energy distributions (SEDs) and radio continuum spectra are presented for a northern sample of 104 extragalactic radio sources, based on the Planck Early Release Compact Source Catalog (ERCSC) and simultaneous multifrequency data. The nine Planck frequencies, from 30 to 857 GHz, are complemented by a set of simultaneous observations ranging from radio to gamma-rays. This is the first extensive frequency coverage in the radio and millimetre domains for an essentially complete sample of extragalactic radio sources, and it shows how the individual shocks, each in their own phase of development, moving in the relativistic jet, shape the radio spectra. The SEDs presented in this paper were fitted with second and third degree polynomials to estimate the frequencies of the synchrotron and inverse Compton (IC) peaks, and the spectral indices of low and high frequency radio data, including the Planck ERCSC data, were calculated. SED modelling methods are discussed, with an emphasis on proper, physical modelli...

  9. A Comparative Study of the Efficiency of Using Non-Selective Nonsteroidal Anti-Inflammatory Drugs in Patients with Endoprosthetic Total Knee and Hip Arthroplasty

    Directory of Open Access Journals (Sweden)

    V. V. Logvinenko

    2012-01-01

    Full Text Available Objective: to compare the postoperative efficacy and safety of non-selective nonsteroidal anti-inflammatory drugs in patients undergoing endoprosthetic total knee and hip arthroplasty (ETKAP and ETHAP. Subjects and methods. The study included 60 patients who were referred for ETKAP or ETHAP and randomly assigned to 3 groups. Groups 1, 2, and 3 patients were anesthetized with ketorolac, metamizol, and paracetamol, respectively. Real-time evaluation of the efficiency of postoperative analgesia was carried out within 3 days after surgery; the patients were questioned about bowel function, the onset of the first active movement in the ward, and occurring unpleasant sensations. Results. Reduced or no appetite was more common in the paracetamol and metamizol groups than in the ketorolac; the paracetamol group was found to have dizziness in 20% of cases, which was not observed in the two other groups. The patients who started to have routine hospital diet in the first 24 postoperative hours were significantly fewer among the paracetamol-treated patients. The shortest time to the first active movement was observed in the ketorolac group, which corresponded to the end of the first 24 hours and significantly distinguished it from the other groups. This appeared to be due to the best analgesic effect that, after epidural block, was significantly more effective (according to VAS scores in the ketorolac group, if not enhanced in any group, which agrees with information available on the drug as a worthy alternative to opioids due to its valid analgesic effect. Conclusion. __Intravenous ketorolac is a worthy alternative to narcotic analgesics in ensuring the comfortable course of the immediate postoperative period in patients operated on the knee and hip joints. Key words: ketorolac (ketorol, postoperative analgesia, endoprosthetic knee and hip arthroplasty.

  10. Effect of selective and non-selective serotonin receptor activation on L-DOPA-induced therapeutic efficacy and dyskinesia in parkinsonian rats.

    Science.gov (United States)

    Tronci, E; Fidalgo, C; Stancampiano, R; Carta, M

    2015-10-01

    Selective activation of 5-HT1 receptors has been shown to produce near to full suppression of L-DOPA-induced dyskinesia (LID) in animal models of Parkinson's disease; however, a reduction of the therapeutic effect of L-DOPA has been reported in several studies. Conversely, we recently found that increasing the serotonergic tone with chronic administration of the serotonin precursor 5-hydroxy-tryptophan (5-HTP) can reduce LID in 6-OHDA-lesioned rats, without affecting L-DOPA efficacy. To directly compare the effects of selective versus non-selective serotonin receptor activation, here we first tested different acute doses of the 5-HT1A/1B receptor agonist eltoprazine and 5-HTP on LID in order to identify doses of the individual compounds showing similar anti-dyskinetic efficacy in L-DOPA-primed dyskinetic rats. About 50% reduction of LID was observed with 0.1 mg/kg and 24 mg/kg of eltoprazine and 5-HTP, respectively; we then compared the effect of the two drugs, individually and in combination, on L-DOPA-induced stepping test in L-DOPA-naïve parkinsonian animals and LID over three weeks of L-DOPA treatment. Results showed that eltoprazine induced significant worsening of L-DOPA-mediated performance in the stepping test, while 5-HTP did not. Interestingly, combination of 5-HTP with eltoprazine prevented the reduction in the forelimb use induced by eltoprazine. Moreover, 5-HTP and eltoprazine given individually showed similar efficacy also upon chronic treatment, and had additive effect in dampening the appearance of LID when given in combination. Finally, chronic administration of eltoprazine and/or 5-HTP did not affect striatal serotonin innervation, compared to l-DOPA alone, as measured by serotonin transporter expression.

  11. Oxidative transformation of micropollutants during municipal wastewater treatment: comparison of kinetic aspects of selective (chlorine, chlorine dioxide, ferrate VI, and ozone) and non-selective oxidants (hydroxyl radical).

    Science.gov (United States)

    Lee, Yunho; von Gunten, Urs

    2010-01-01

    Chemical oxidation processes have been widely applied to water treatment and may serve as a tool to minimize the release of micropollutants (e.g. pharmaceuticals and endocrine disruptors) from municipal wastewater effluents into the aquatic environment. The potential of several oxidants for the transformation of selected micropollutants such as atenolol, carbamazepine, 17 alpha-ethinylestradiol (EE2), ibuprofen, and sulfamethoxazole was assessed and compared. The oxidants include chlorine, chlorine dioxide, ferrate(VI), and ozone as selective oxidants versus hydroxyl radicals as non-selective oxidant. Second-order rate constants (k) for the reaction of each oxidant show that the selective oxidants react only with some electron-rich organic moieties (ERMs), such as phenols, anilines, olefins, and deprotonated-amines. In contrast, hydroxyl radicals show a nearly diffusion-controlled reactivity with almost all organic moieties (k>or=10(9)M(-1) s(-1)). Due to a competition for oxidants between a target micropollutant and wastewater matrix (i.e. effluent organic matter, EfOM), a higher reaction rate with a target micropollutant does not necessarily translate into more efficient transformation. For example, transformation efficiencies of EE2, a phenolic micropollutant, in a selected wastewater effluent at pH 8 varied only within a factor of 7 among the selective oxidants, even though the corresponding k for the reaction of each selective oxidant with EE2 varied over four orders of magnitude. In addition, for the selective oxidants, the competition disappears rapidly after the ERMs present in EfOM are consumed. In contrast, for hydroxyl radicals, the competition remains practically the same during the entire oxidation. Therefore, for a given oxidant dose, the selective oxidants were more efficient than hydroxyl radicals for transforming ERMs-containing micropollutants, while hydroxyl radicals are capable of transforming micropollutants even without ERMs. Besides Ef

  12. A trs20 mutation that mimics an SEDT-causing mutation blocks selective and non-selective autophagy: a model for TRAPP III organization.

    Science.gov (United States)

    Brunet, Stephanie; Shahrzad, Nassim; Saint-Dic, Djenann; Dutczak, Hartley; Sacher, Michael

    2013-10-01

    TRAPP is a multisubunit complex that functions in membrane traffic. Mutations in the mammalian TRAPP protein C2 are linked to the skeletal disorder spondyloepiphyseal dysplasia tarda (SEDT) that is thought to arise from an inability to secrete procollagen from the endoplasmic reticulum. Here, we show that C2 binds to the SNARE protein Syntaxin 5 and this interaction is weakened by an SEDT-causing missense mutation (D47Y). Interestingly, the equivalent mutation (D46Y) in the yeast C2 homolog Trs20p does not block anterograde traffic but did affect endocytosis. The trs20D46Y mutation interfered with the interaction between Trs20p and Trs85p (TRAPP III-specific subunit), Trs120p and Trs130p (TRAPP II-specific subunits). Size exclusion chromatography suggested that this yeast mutation destabilized the TRAPP III complex that is involved in autophagy. We further show that this mutation blocks both the selective cytosol-to-vacuole (cvt) pathway as well as non-selective autophagy. We demonstrate that the apparent molecular size of the TRAPP III complex is dependent upon membranes, and that the presence of TRAPP III is dependent upon Atg9p. Finally, we demonstrate that lipidated Bet3p is enriched in TRAPP III and that lipidation increases the efficiency of autophagy. Our study suggests that Trs20p acts as an adaptor for Trs85p and Trs120p and reveals complexities in TRAPP III assembly and function. The implications of C2D47Y in SEDT are discussed. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  13. The selective and non-selective cyclooxygenase inhibitors valdecoxib and piroxicam induce the same postoperative analgesia and control of trismus and swelling after lower third molar removal

    Directory of Open Access Journals (Sweden)

    V. Benetello

    2007-08-01

    Full Text Available We compared the clinical efficacy of orally administered valdecoxib and piroxicam for the prevention of pain, trismus and swelling after removal of horizontally and totally intrabony impacted lower third molars. Twenty-five patients were scheduled to undergo removal of symmetrically positioned lower third molars in two separate appointments. Valdecoxib (40 mg or piroxicam (20 mg was administered in a double-blind, randomized and crossed manner for 4 days after the surgical procedures. Objective and subjective parameters were recorded for comparison of postoperative courses. Both agents were effective for postoperative pain relief (N = 19. There was a similar mouth opening at suture removal compared with the preoperative values (86.14 ± 4.36 and 93.12 ± 3.70% of the initial measure for valdecoxib and piroxicam, respectively; ANOVA. There was no significant difference regarding the total amount of rescue medication taken by the patients treated with valdecoxib or piroxicam (173.08 ± 91.21 and 461.54 ± 199.85 mg, respectively; Wilcoxon test. There were no significant differences concerning the swelling observed on the second postoperative day compared to baseline measures (6.15 ± 1.84 and 8.46 ± 2.04 mm for valdecoxib and piroxicam, respectively; ANOVA or on the seventh postoperative day (1.69 ± 1.61 and 2.23 ± 2.09 mm for valdecoxib and piroxicam, respectively; ANOVA. The cyclooxygenase-2 selective inhibitor valdecoxib is as effective as the non-selective cyclooxygenase inhibitor piroxicam for pain, trismus and swelling control after removal of horizontally and totally intrabony impacted lower third molars.

  14. COMPARISON OF SELECTIVE AND NON SELECTIVE CYCLO-OXYGENASE 2 INHIBITORS IN EXPERIMENTAL COLITIS EXACERBATION: role of leukotriene B4 and superoxide dismutase

    Directory of Open Access Journals (Sweden)

    José Wander BREGANÓ

    2014-09-01

    Full Text Available Context Nonsteroidal anti-inflammatory drugs are considered one of the most important causes of reactivation of inflammatory bowel disease. With regard to selective cyclo-oxygenase 2 inhibitors, the results are controversial in experimental colitis as well as in human studies. Objectives The aim this study is to compare nonsteroidal anti-inflammatory drugs effects, selective and non selective cyclo-oxygenase 2 inhibitors, in experimental colitis and contribute to the understanding of the mechanisms which nonsteroidal anti-inflammatory drugs provoke colitis exacerbation. Methods Six groups of rats: without colitis, with colitis, and colitis treated with celecoxib, ketoprofen, indometacin or diclofenac. Survival rates, hemoglobin, plasmatic albumin, colonic tissue of interleukin-1ß, interleukin-6, tumor necrosis factor alpha, prostaglandin E2, catalase, superoxide dismutase, thiobarbituric acid-reactive substances, chemiluminescence induced by tert-butil hydroperoxides, and tissue and plasmatic leukotriene B4 were determined. Results The groups treated with diclofenac or indometacin presented lower survival rates, hemoglobin and albumin, higher tissue and plasmatic leukotriene B4 and tissue superoxide dismutase than the group treated with celecoxib. Ketoprofen presented an intermediary behavior between diclofenac/indometacin and celecoxib, concerning to survival rate and albumin. The groups without colitis, with colitis and with colitis treated with celecoxib showed leukotriene B4 and superoxide dismutase lower levels than the groups treated with nonselective cyclo-oxygenase 2 inhibitors. Conclusions Diclofenac and indometacin presented the highest degree of induced colitis exacerbation with nonsteroidal anti-inflammatory drugs, celecoxib did not show colitis exacerbation, and ketoprofen presented an intermediary behavior between diclofenac/indometacin and celecoxib. These results suggest that leukotriene B4 and superoxide dismutase can be

  15. A COMPARATIVE STUDY OF CHAIN DYNAMICS OF DI-AND TRI-BLOCK COPOLYMERS IN SEMIDILUTE SOLUTION IN A NON-SELECTIVE SOLVENT

    Institute of Scientific and Technical Information of China (English)

    Wei Li; Liang-zhi Hong; To Ngai; Hai-ying Huang; Tian-bai He; Chi Wu

    2004-01-01

    The chain dynamics of a pair of diblock poly(styrene-b-butadiene) (PS210-b-PB960) and triblock poly(styrene-b-butadiene-b-styrene) (PS200-b-PB1815-b-PS200) copolymers in both dilute and semidilute toluene solutions has been comparatively studied by dynamic laser light scattering. As expected, the mutual diffusion of individual chain changes into a fast cooperative diffusion of the chain segments ("blobs") between two neighboring entanglement points for both the copolymers as the solution changes from dilute to semidilute. Further increases of the concentration lead to a second slow relaxation mode. For the triblock chains, there exists an additional middle relaxation between the fast and the slow modes.with 0.33 <α< 0.44, much smaller than 0.75 predicted or 0.72 observed for linear homopolymer chains in good solvent. It implies that the solvent quality of toluene for PB might not be as good as that for PS. Due to such a difference in solubility, it is reasonable to speculate that the PB and PS blocks are transiently segregated in semidilute solution. The relaxation of these transient PB and PS richer domains leads to the observed slow relaxation. Such a speculation is supported by the appearance of an additional slow relaxation mode in the study of polyisoprene-b-polystyrene-b-polyisoprene in semidilute solution in cyclohexane, a non-selective solvent, in which we alternated the solubility difference by a variation of the solution temperature.

  16. Radio language teaching in Kenyan sch

    Directory of Open Access Journals (Sweden)

    Maurice Imhoof

    2013-02-01

    Full Text Available The Radio Language Arts Project in Kenya is currently testing the feasibility of using radio intensively to serve as the major medium of English instruction in the formal classroom setting. The project, now in its third and final year of lesson development and experimentation, is evaluating the effectiveness of radio in teaching English to children in the first three primary grades. The thirty-minute, daily broacasts are part of the normal school curriculum. Preliminary results show substantial achievement gains by the radio students and strong support from school personnel. The project demonstrates that carefully designed, written, and produced radio lessons, aided by human interaction fostered by a teacher or other guide, can be an effective alternative to more complex and more costly techniques. In Kenia word die uitvoerbaarheid daarvan om die radio intensief te gebruik as die belangrikste medium by die onderrig van Engels in die formele klassituasie, getoets deur projek "Radio Language Arts". Die projek, wat tans in sy derde en finale jaar van lesontwikkeling en eksperimentasie verkeer, evalueer die doeltreffendheid van die radio in Engels-onderrig aan kinders in die eerste drie jaar van die primere skool. Die halfuur lange, daaglikse uitsendings vorm deel van die norm ale kurrikulum. Voorlopige resultate vertoon aansienlike winste in die prestasies van radio-leerlinge en 'n sterk aanhang deur personeel. Die projek demonstreer dat noukeurig ontwerpte, geskrewe en uitgevoerde radio-lesse, ondersteun deur menslike interaksie in die vorm van 'n onderwyser of gids, 'n doeltreffende alternatief kan wees vir meer ingewikkelde en duur metodes.

  17. Microbial radio-resistance of Salmonella Typhimurium in egg increases due to repetitive irradiation with electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Tesfai, Adiam T.; Beamer, Sarah K.; Matak, Kristen E. [West Virginia University, Division of Animal and Nutritional Sciences, PO Box 6108, Morgantown, WV 26508 (United States); Jaczynski, Jacek, E-mail: Jacek.Jaczynski@mail.wvu.ed [West Virginia University, Division of Animal and Nutritional Sciences, PO Box 6108, Morgantown, WV 26508 (United States)

    2011-04-15

    Ionizing radiation improves food safety. However, foodborne pathogens develop increased resistance in response to sub-lethal stresses such as heat, pH, antibiotics, etc. Therefore, it is hypothesized that foodborne pathogens may develop increased radio-resistance to electron beam (e-beam) radiation. The objective was to determine if D{sub 10}-value for Salmonella Typhimurium in de-shelled raw egg (egg white and yolk mixed together) increases due to repetitive processing with e-beam at sub-lethal doses. Survivors were enumerated on non-selective (TSA) and selective (XLD) media. Survivors from the highest dose were isolated and used in subsequent e-beam cycle. This process was repeated four times for a total of five e-beam cycles. D{sub 10}-values for S. Typhimurium enumerated on TSA and XLD following each e-beam cycle were calculated as inverse reciprocal of the slope of survivor curves. D{sub 10}-values for the ATCC strain were 0.59{+-}0.031 and 0.46{+-}0.022 kGy on TSA and XLD, respectively. However, following the fifth e-beam cycle, the respective D{sub 10}-values increased (P<0.05) to 0.69{+-}0.026 and 0.61{+-}0.029 kGy, respectively. S. Typhimurium showed a trend (P>0.05) to develop radio-resistance faster on selective media, likely due to facilitated selection of radio-resistant cells within microbial population following each e-beam cycle. For all five e-beam cycles, S. Typhimurium had higher (P<0.05) D{sub 10}-values on non-selective media, indicating that sub-lethal injury followed by cellular repair and recovery are important for radio-resistance and inactivation of this microorganism. This study demonstrated that e-beam efficiently inactivates S. Typhimurium in raw egg; however, similar to other inactivation techniques and factors affecting microbial growth, S. Typhimurium develops increased radio-resistance if repetitively processed with e-beam at sub-lethal doses.

  18. 77 FR 50053 - Radio Broadcasting Services; Westley, CA

    Science.gov (United States)

    2012-08-20

    ... 73 Radio, Radio broadcasting. Federal Communications Commission. Peter H. Doyle, Chief, Audio.... FOR FURTHER INFORMATION CONTACT: Michael Wagner, Media Bureau, (202) 418-2700 or Rolanda F. Smith...

  19. Bayesian Inference for Radio Observations

    CERN Document Server

    Lochner, Michelle; Zwart, Jonathan T L; Smirnov, Oleg; Bassett, Bruce A; Oozeer, Nadeem; Kunz, Martin

    2015-01-01

    (Abridged) New telescopes like the Square Kilometre Array (SKA) will push into a new sensitivity regime and expose systematics, such as direction-dependent effects, that could previously be ignored. Current methods for handling such systematics rely on alternating best estimates of instrumental calibration and models of the underlying sky, which can lead to inaccurate uncertainty estimates and biased results because such methods ignore any correlations between parameters. These deconvolution algorithms produce a single image that is assumed to be a true representation of the sky, when in fact it is just one realisation of an infinite ensemble of images compatible with the noise in the data. In contrast, here we report a Bayesian formalism that simultaneously infers both systematics and science. Our technique, Bayesian Inference for Radio Observations (BIRO), determines all parameters directly from the raw data, bypassing image-making entirely, by sampling from the joint posterior probability distribution. Thi...

  20. Can Radio Telescopes Find Axions?

    Science.gov (United States)

    Kohler, Susanna

    2017-08-01

    axions. Now scientists Katharine Kelley and Peter Quinn at ICRAR, University of Western Australia, have explored how we might use next-generation radio telescopes to search for photons that were created by axions interacting with the magnetic fields of our galaxy.Hope for Next-Gen TelescopesPotential axion coupling strengths vs. mass (click for a closer look). The axion mass is thought to lie between a eV and a meV; two theoretical models are shown with dashed lines. The plot shows the sensitivity of the upcoming SKA and its precursors, ASKAP and MEERKAT. [KelleyQuinn 2017]By using a simple galactic halo model and reasonable assumptions for the central galactic magnetic field even taking into account the time dependence of the field Kelley and Quinn estimate the radio-frequency power density that we would observe at Earth from axions being converted to photons within the Milky Ways magnetic field.The authors then compare this signature to the detection capabilities of upcoming radio telescope arrays. They show that the upcoming Square Kilometer Array and its precursors should have the capability to detect signs of axions across large parts of parameter space.Kelley and Quinn conclude that theres good cause for optimism about future radio telescopes ability to detect axions. And if we did succeed in making a detection, it would be a triumph for both particle physics and astrophysics, finally providing an explanation for the universes dark matter.CitationKatharine Kelley and P. J. Quinn 2017 ApJL 845 L4. doi:10.3847/2041-8213/aa808d

  1. Direct Broadcast Satellite: Radio Program

    Science.gov (United States)

    Hollansworth, James E.

    1992-01-01

    NASA is committed to providing technology development that leads to the introduction of new commercial applications for communications satellites. The Direct Broadcast Satellite-Radio (DBS-R) Program is a joint effort between The National Aeronautics and Space Administration (NASA) and The United States Information Agency/Voice of America (USIA/VOA) directed at this objective. The purpose of this program is to define the service and develop the technology for a direct-to-listener satellite sound broadcasting system. The DBS-R Program, as structured by NASA and VOA, is now a three-phase program designed to help the U.S. commercial communications satellite and receiver industry bring about this new communications service. Major efforts are being directed towards frequency planning hardware and service development, service demonstration, and experimentation with new satellite and receiver technology.

  2. The LWA1 Radio Telescope

    CERN Document Server

    Ellingson, S W; Craig, J; Hartman, J; Dowell, J; Wolfe, C N; Clarke, T E; Hicks, B C; Kassim, N E; Ray, P S; Rickard, L J; Schinzel, F K; Weiler, K W

    2012-01-01

    LWA1 is a new radio telescope operating in the frequency range 10-88 MHz, located in central New Mexico. The telescope consists of 258 pairs of dipole-type antennas whose outputs are individually digitized and formed into beams. Simultaneously, signals from all dipoles can be recorded using one of the instrument's "all dipoles" modes, facilitating all-sky imaging. Notable features of the instrument include high intrinsic sensitivity (about 6 kJy zenith system equivalent flux density), large instantaneous bandwidth (up to 78 MHz), and 4 independently-steerable beams utilizing digital "true time delay" beamforming. This paper summarizes the design of LWA1 and its performance as determined in commissioning experiments. We describe the method currently in use for array calibration, and report on measurements of sensitivity and beamwidth.

  3. Breve historia de Radio Sahara

    Directory of Open Access Journals (Sweden)

    Montes Fernández, Francisco José

    2013-01-01

    Full Text Available La historia de Radio Sahara es uno de los períodos menos estudiado en nuestra bibliografía, lo cual tampoco es sintomático sino una muestra más de lo mucho que hay que investigar sobre la historia reciente denuestro país, especialmente en el terreno de la radiodifusión. He profundizado en todo lo que he podido, pero es indudable que queda mucho camino por recorrer. Aquí hay pistas y datos todos verdaderos sobre una parte importante, pero no lo doy por finalizado sino que aspiro a que sirva de aliciente para que futuros investigadores continúen con el camino iniciado. Se trata de describir lo que fue la historia de esta emisora

  4. Grote Reber, Radio Astronomy Pioneer, Dies

    Science.gov (United States)

    2002-12-01

    Grote Reber, one of the earliest pioneers of radio astronomy, died in Tasmania on December 20, just two days shy of his 91st birthday. Reber was the first person to build a radio telescope dedicated to astronomy, opening up a whole new "window" on the Universe that eventually produced such landmark discoveries as quasars, pulsars and the remnant "afterglow" of the Big Bang. His self- financed experiments laid the foundation for today's advanced radio-astronomy facilities. Grote Reber Grote Reber NRAO/AUI photo "Radio astronomy has changed profoundly our understanding of the Universe and has earned the Nobel Prize for several major contributions. All radio astronomers who have followed him owe Grote Reber a deep debt for his pioneering work," said Dr. Fred Lo, director of the National Radio Astronomy Observatory (NRAO). "Reber was the first to systematically study the sky by observing something other than visible light. This gave astronomy a whole new view of the Universe. The continuing importance of new ways of looking at the Universe is emphasized by this year's Nobel Prizes in physics, which recognized scientists who pioneered X-ray and neutrino observations," Lo added. Reber was a radio engineer and avid amateur "ham" radio operator in Wheaton, Illinois, in the 1930s when he read about Karl Jansky's 1932 discovery of natural radio emissions coming from outer space. As an amateur operator, Reber had won awards and communicated with other amateurs around the world, and later wrote that he had concluded "there were no more worlds to conquer" in radio. Learning of Jansky's discovery gave Reber a whole new challenge that he attacked with vigor. Analyzing the problem as an engineer, Reber concluded that what he needed was a parabolic-dish antenna, something quite uncommon in the 1930s. In 1937, using his own funds, he constructed a 31.4-foot-diameter dish antenna in his back yard. The strange contraption attracted curious attention from his neighbors and became

  5. Brightest Cluster Galaxies in the Extended GMRT radio halo cluster sample. Radio properties and cluster dynamics

    CERN Document Server

    Kale, Ruta; Cassano, Rossella; Giacintucci, Simona; Bardelli, sandro; Dallacasa, Daniele; Zucca, Elena

    2015-01-01

    Brightest Cluster Galaxies (BCGs) show exceptional properties over the whole electromagnetic spectrum. Their special location at the centres of galaxy clusters raises the question of the role of the environment on their radio properties. To decouple the effect of the galaxy mass and of the environment in their statistical radio properties, we investigate the possible dependence of the occurrence of radio loudness and of the fractional radio luminosity function on the dynamical state of the hosting cluster. We studied the radio properties of the BCGs in the Extended GMRT Radio Halo Survey (EGRHS). We obtained a statistical sample of 59 BCGs, which was divided into two classes, depending on the dynamical state of the host cluster, i.e. merging (M) and relaxed (R). Among the 59 BCGs, 28 are radio-loud, and 31 are radio--quiet. The radio-loud sources are located favourably located in relaxed clusters (71\\%), while the reverse is true for the radio-quiet BCGs, mostly located in merging systems (81\\%). The fraction...

  6. Characterising Radio Emissions in Cosmic Filaments

    Science.gov (United States)

    Miller, R. O.

    2014-02-01

    A growing number of radio studies probe galaxy clusters into the low-power regime in which star formation is the dominant source of radio emission. However, at the time of writing no comparably deep observations have focused exclusively on the radio populations of cosmic filaments. This thesis describes the ATCA 2.1 GHz observations and subsequent analysis of two such regions - labelled Zone 1 (between clusters A3158 and A3125/A3128) and Zone 2 (between A3135 and A3145) - in the Horologium-Reticulum Supercluster (HRS). Source count profiles of both populations are discussed and a radio luminosity function for Zone 1 is generated. While the source counts of Zone 2 appear to be consistent with expected values, Zone 1 exhibits an excess of counts across a wide flux range (1 mJy< S_1.4 < 200 mJy). An excess in radio activity at the lower extent of this range (log P_1.4 < 22.5; within the SF-dominated regime) is also suggested by the radio luminosity function for that region, and brief colour analysis suggests that such an excess is indeed predominantly associated with a starforming population. The differences between the two filamentary zones is attributed to cosmic variation. The regions are both small (~ 1 degree square), and are significantly separated in the HRS. Further radio observations of filaments are required and the results combined into a larger sample size in order to arrive at a generalised model filamentary population.

  7. Giant Radio Galaxies: I. Intergalactic Barometers

    CERN Document Server

    Malarecki, J M; Saripalli, L; Subrahmanyan, R; Jones, D H; Duffy, A R; Rioja, M

    2013-01-01

    We present new wideband radio observations with the Australia Telescope Compact Array of a sample of 12 giant radio galaxies. The radio observations are part of a larger radio-optical study aimed at relating the radio structures with the ambient medium on large scales. With projected linear sizes larger than 0.7 Mpc, these objects are ideal candidates for the study of the Warm-Hot Intergalactic Medium (WHIM). The sample includes sources with sizes spanning 0.8 to 3.2 Mpc and total powers of 1.2*10^24 to 4.0*10^26 W Hz^-1 at 2.1 GHz. Redshifts were limited to z<0.15 to permit spectroscopic observations of the hosts and neighbouring galaxies, which were obtained using the AAOmega spectrograph on the Anglo-Australian Telescope. We derive lobe energy densities from the radio observations via equipartition arguments. The inferred pressures in the lobes of the giant radio sources, which range from 1.1*10^-15 to 2.0*10^-14 Pa (80 to 1500 cm^-3 K), are lower than previously inferred from X-ray observations of dens...

  8. RADIO FLARES FROM GAMMA-RAY BURSTS

    Energy Technology Data Exchange (ETDEWEB)

    Kopač, D.; Mundell, C. G.; Kobayashi, S.; Virgili, F. J. [Astrophysics Research Institute, Liverpool John Moores University, Liverpool, L3 5RF (United Kingdom); Harrison, R. [Department of Astrophysics, School of Physics and Astronomy, Tel Aviv University, 69978 Tel Aviv (Israel); Japelj, J.; Gomboc, A. [Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana (Slovenia); Guidorzi, C. [Department of Physics and Earth Sciences, University of Ferrara, Via Saragat, 1, I-44122 Ferrara (Italy); Melandri, A., E-mail: D.Kopac@ljmu.ac.uk [INAF/Brera Astronomical Observatory, via Bianchi 46, I-23807, Merate (Italy)

    2015-06-20

    We present predictions of centimeter and millimeter radio emission from reverse shocks (RSs) in the early afterglows of gamma-ray bursts (GRBs) with the goal of determining their detectability with current and future radio facilities. Using a range of GRB properties, such as peak optical brightness and time, isotropic equivalent gamma-ray energy, and redshift, we simulate radio light curves in a framework generalized for any circumburst medium structure and including a parameterization of the shell thickness regime that is more realistic than the simple assumption of thick- or thin-shell approximations. Building on earlier work by Mundell et al. and Melandri et al. in which the typical frequency of the RS was suggested to lie at radio rather than optical wavelengths at early times, we show that the brightest and most distinct RS radio signatures are detectable up to 0.1–1 day after the burst, emphasizing the need for rapid radio follow-up. Detection is easier for bursts with later optical peaks, high isotropic energies, lower circumburst medium densities, and at observing frequencies that are less prone to synchrotron self-absorption effects—typically above a few GHz. Given recent detections of polarized prompt gamma-ray and optical RS emission, we suggest that detection of polarized radio/millimeter emission will unambiguously confirm the presence of low-frequency RSs at early time.

  9. The reproducible radio outbursts of SS Cygni

    Science.gov (United States)

    Russell, T. D.; Miller-Jones, J. C. A.; Sivakoff, G. R.; Altamirano, D.; O'Brien, T. J.; Page, K. L.; Templeton, M. R.; Körding, E. G.; Knigge, C.; Rupen, M. P.; Fender, R. P.; Heinz, S.; Maitra, D.; Markoff, S.; Migliari, S.; Remillard, R. A.; Russell, D. M.; Sarazin, C. L.; Waagen, E. O.

    2016-08-01

    We present the results of our intensive radio observing campaign of the dwarf nova SS Cyg during its 2010 April outburst. We argue that the observed radio emission was produced by synchrotron emission from a transient radio jet. Comparing the radio light curves from previous and subsequent outbursts of this system (including high-resolution observations from outbursts in 2011 and 2012) shows that the typical long and short outbursts of this system exhibit reproducible radio outbursts that do not vary significantly between outbursts, which is consistent with the similarity of the observed optical, ultraviolet and X-ray light curves. Contemporaneous optical and X-ray observations show that the radio emission appears to have been triggered at the same time as the initial X-ray flare, which occurs as disc material first reaches the boundary layer. This raises the possibility that the boundary region may be involved in jet production in accreting white dwarf systems. Our high spatial resolution monitoring shows that the compact jet remained active throughout the outburst with no radio quenching.

  10. Radio Science Measurements with Suppressed Carrier

    Science.gov (United States)

    Asmar, Sami; Divsalar, Dariush; Oudrhiri, Kamal

    2013-01-01

    Radio Science started when it became apparent with early Solar missions that occultations by planetary atmospheres would affect the quality of radio communications. Since then the atmospheric properties and other aspects of planetary science, solar science, and fundamental physics were studied by scientists. Radio Science data was always extracted from a received pure residual carrier (without data modulation). For some missions, it is very desirable to obtain Radio Science data from a suppressed carrier modulation. In this paper we propose a method to extract Radio Science data when a coded suppressed carrier modulation is used in deep space communications. Type of modulation can be BPSK, QPSK, OQPSK, MPSK or even GMSK. However we concentrate mostly on BPSK modulation. The proposed method for suppressed carrier simply tries to wipe out data that acts as an interference for Radio Science measurements. In order to measure the estimation errors in amplitude and phase of the Radio Science data we use Cramer-Rao bound (CRB). The CRB for the suppressed carrier modulation with non-ideal data wiping is then compared with residual carrier modulation under the same noise condition. The method of derivation of CRB for non-ideal data wiping is an innovative method that presented here. Some numerical results are provided for coded system.

  11. Radio Properties of Brightest Cluster Members

    CERN Document Server

    Andernach, H

    2009-01-01

    We searched the literature for radio images and fluxes of brightest cluster members (BCMs) in 1169 Abell clusters, selected on the basis of their BM or RS type or on textual notes in the Abell catalog indicating the presence of dominant galaxies. We inspected the images of existing radio surveys (NVSS, SUMSS, FIRST, WENSS, etc.) and used the CATS and VizieR catalog browsers, as well as additional literature, to collect radio fluxes and radio morphologies for 1423 BCMs. We found 578 (41%) of these BCMs with detected radio emission, of which 223 are detected at only a single frequency. Using the survey images and published high-resolution images, we estimated the best available position angle for the innermost radio structure and for the largest angular size of each source. DSS images were used to obtain the orientation of the optical major axis of the outer envelope of the BCMs, and the acute difference angle between major optical and radio axes was derived for 102 objects. Its distribution shows a similar bim...

  12. THE FUNDAMENTAL PLANE FOR RADIO MAGNETARS

    Energy Technology Data Exchange (ETDEWEB)

    Rea, Nanda; Torres, Diego F. [Institut de Ciencies de l' Espai (CSIC-IEEC), Campus UAB, Torre C5, 2a Planta, 08193 Barcelona (Spain); Pons, Jose A. [Departament de Fisica Aplicada, Universitat d' Alacant, Ap. Correus 99, 03080 Alacant (Spain); Turolla, Roberto [Dipartimento di Fisica e Astronomia, Universita di Padova, via F. Marzolo 8, I-35131 Padova (Italy)

    2012-03-20

    High magnetic fields are a distinguishing feature of neutron stars and the existence of sources (the soft gamma repeaters, SGRs, and the anomalous X-ray pulsars) hosting an ultramagnetized neutron star (or magnetar) has been recognized in the past few decades. Magnetars are believed to be powered by magnetic energy and not by rotation, as with normal radio pulsars. Until recently, the radio quietness and magnetic fields typically above the quantum critical value (B{sub Q} {approx_equal} 4.4 Multiplication-Sign 10{sup 13} G) were among the characterizing properties of magnetars. The recent discovery of radio-pulsed emission from a few of them, and of a low dipolar magnetic field SGR, weakened further the idea of a clean separation between normal pulsars and magnetars. In this Letter, we show that radio emission from magnetars might be powered by rotational energy, similarly to what occurs in normal radio pulsars. The peculiar characteristics of magnetars radio emission should be traced in the complex magnetic geometry of these sources. Furthermore, we propose that magnetar radio activity or inactivity can be predicted from the knowledge of the star's rotational period, its time derivative, and the quiescent X-ray luminosity.

  13. Radio Wave Propagation and the Provenance of Fast Radio Bursts

    CERN Document Server

    Cordes, J M; Spitler, L G; Chatterjee, S; Wasserman, I

    2016-01-01

    We analyze plasma dispersion and scattering of fast radio bursts (FRBs) to identify the dominant locations of free electrons along their lines of sight and thus constrain the distances of the burst sources themselves. We establish the average $\\tau$-DM relation for Galactic pulsars and use it as a benchmark for discussing FRB scattering. Though scattering times $\\tau$ for FRBs are large in the majority of the 17 events we analyze, they are systematically smaller than those of Galactic pulsars that have similar dispersion measures (DMs). The lack of any correlation between $\\tau$ and DM for FRBs suggests that the intergalactic medium (IGM) cannot account for both $\\tau$ and DM. We therefore consider mixed models involving the IGM and host galaxies. If the IGM contributes significantly to DM while host galaxies dominate $\\tau$, the scattering deficit with respect to the mean Galactic trend can be explained with a $\\tau$-DM relation in the host that matches that for the Milky Way. However, it is possible that ho...

  14. Radio Interferometric Calibration Using a Riemannian Manifold

    CERN Document Server

    Yatawatta, Sarod

    2013-01-01

    In order to cope with the increased data volumes generated by modern radio interferometers such as LOFAR (Low Frequency Array) or SKA (Square Kilometre Array), fast and efficient calibration algorithms are essential. Traditional radio interferometric calibration is performed using nonlinear optimization techniques such as the Levenberg-Marquardt algorithm in Euclidean space. In this paper, we reformulate radio interferometric calibration as a nonlinear optimization problem on a Riemannian manifold. The reformulated calibration problem is solved using the Riemannian trust-region method. We show that calibration on a Riemannian manifold has faster convergence with reduced computational cost compared to conventional calibration in Euclidean space.

  15. ARCADE Detection of an Extragalactic Radio Background

    Science.gov (United States)

    Kogut, Alan J.

    2009-01-01

    Sometimes when we look for one thing we stumble on something else. The Absolute Radiometer for Cosmology, Astrophysics, and Diffuse Emission (ARCADE) was designed to measure the blackbody spectrum of the cosmic microwave background to search for spectral distortions related to the epoch of reionization. Instead, the July 2006 flight found evidence for an extragalactic radio background with amplitude six times brighter than the expected contribution from faint radio sources. The author discusses the ARCADE instrument and the evidence for an extragalactic radio background.

  16. Nature of microstructure in pulsar radio emission

    CERN Document Server

    Machabeli, G Z; Melikidze, G I; Shapakidze, D; Machabeli, George; Khechinashvili, David; Melikidze, George; Shapakidze, David

    2000-01-01

    We present a model for microstructure in pulsar radio emission. We propose that micropulses result from the alteration of the radio wave generation region by nearly transverse drift waves propagating across the pulsar magnetic field and encircling the bundle of the open magnetic field lines. It is demonstrated that such waves can modify significantly curvature of these dipolar field lines. This in turn affects strongly fulfillment of the resonance conditions necessary for the excitation of radio waves. The time-scale of micropulses is therefore determined by the wavelength of drift waves. Main features of the microstructure are naturally explained in the frame of this model.

  17. Compact radio cores in seyfert galaxies

    CERN Document Server

    Roy, A L; Kesteven, M J; Troup, E R; Reynolds, J E

    1994-01-01

    Abstract We have observed a sample of 157 Seyfert galaxies with a 275 km baseline radio interferometer to search for compact, high brightness temperature radio emission from the active nucleus. We obtain the surprising result that compact radio cores are much more common in Seyfert 2 than in Seyfert 1 galaxies, which at first seems to be inconsistent with orientation unification schemes. We propose a model, involving optical depth effects in the narrow-line region, which can reconcile our result with the standard unified scheme. (Accepted for publication in ApJ 1994 Sep 10)

  18. Application of mesh network radios to UGS

    Science.gov (United States)

    Calcutt, Wade; Jones, Barry; Roeder, Brent

    2008-04-01

    During the past five years McQ has been actively pursuing integrating and applying wireless mesh network radios as a communications solution for unattended ground sensor (UGS) systems. This effort has been rewarded with limited levels of success and has ultimately resulted in a corporate position regarding the use of mesh network radios for UGS systems. A discussion into the background of the effort, the challenges of implementing commercial off-the-shelf (COTS) mesh radios with UGSs, the tradeoffs involved, and an overview of the future direction is presented.

  19. DARPA NetCentric radio demonstration

    Science.gov (United States)

    Stotts, Larry B.; Seidel, Scott; Krout, Tim; Kolodzy, Paul

    2007-04-01

    The objective of the DARPA Network Centric Radio System1 (NCRS) Program was to design, develop, integrate, and demonstrate the enabling communication technologies and system capabilities required to enable network centric warfare. NCRS is a First Generation Mobile, Ad Hoc Network (MANET) designed to enable ground and airborne vehicle based on-the-move and on-the-halt network centric connectivity. It demonstrated a gateway architecture that offers interoperability among various current, future, coalition and first responder communications radios, via the network, not the radio. This capability illustrated a new dimension for military communications interoperability.

  20. Parsec-scale radio structures in Quasars

    Science.gov (United States)

    Coldwell, G.; Paragi, Z.; Gurvits, L.

    Very Long Baseline Interferometry (VLBI) con su nueva extensión para el radio telescopio orbital, VSOP/HALCA, ofrece una incomparable resolución angular alcanzando escalas de milisegundos y submilisegundos de arco a longitudes de onda de centímetros. En este trabajo presentamos observaciones y análisis de estructuras en radio, en escalas de parsec, para 3 radio fuentes extragalácticas de la muestra de VSOP Survey y 1 quasar, 1442+101, del proyecto `VSOP High Redshift'.

  1. Deep images of cluster radio halos

    CERN Document Server

    Bacchi, M; Giovannini, G; Govoni, F

    2003-01-01

    New radio data are presented for the clusters A401, A545, A754, A1914, A2219 and A2390, where the presence of diffuse radio emission was suggested from the images of the NRAO VLA Sky Survey. Sensitive images of these clusters, obtained with the Very Large Array (VLA)at 20 cm confirm the existence of the diffuse sources and allow us to derive their fluxes and intrinsic parameters.The correlation between the halo radio power and cluster X-ray luminosity is derived for a large sample of halo clusters, and is briefly discussed.

  2. Radio Channel State Prediction by Kalman Filter

    Directory of Open Access Journals (Sweden)

    Peter Ziacik

    2005-01-01

    Full Text Available In this article there is the description Kalman filter using as a radio channel state predictor. Simulator of prediction has been created in MATLAB environment and it is capable to simulate the prediction of radio signal envelope by Clark’s model of radio channel, which is implemented to the simulator. Simulations were realized for prediction range 0.41 ms and 6.24 ms and as comparing criterion we used the prediction error. It is clear from simulations, that with the duration of prediction the prediction error is enlarging, which may cause the erroneous decision of adaptation algorithms.

  3. The kpc-scale radio source population

    OpenAIRE

    Augusto, Pedro; Gonzalez-Serrano, J. Ignacio; Edge, Alastair C.; Gizani, Nectaria A. B.; Wilkinson, Peter N.; Perez-Fournon, Ismael

    1999-01-01

    We are conducting a multi-wavelength (radio, optical, and X-ray) observational campaign to classify, morphologically and physically, a sample of 55 flat-spectrum radio sources dominated by structure on kpc-scales. This sample contains 22 compact-/medium-sized symmetric object candidates, a class of objects thought to be the early stages of the evolution of radio galaxies. The vast majority of the remaining objects have core-plus-one-sided-jet structures, half of which present sharply bent jet...

  4. Rotating Radio Transients: X-ray observations

    CERN Document Server

    Rea, Nanda

    2007-01-01

    Rotating Radio Transients (RRATs) are a new class of neutron stars discovered through the emission of radio bursts. Eleven sources are known up to now, but population studies predict these objects to be more numerous than the normal radio pulsar population. Multiwavelength observations of these peculiar objects are in progress to disentangle their spectral energy distribution, and then study in detail their nature. In this review I report on the current state of the art on these objects, and in particular on the results of new X-ray observations.

  5. Pulse Compression Technique of Radio Fuze

    Institute of Scientific and Technical Information of China (English)

    HU Xiu-juan; DENG Jia-hao; SANG Hui-ping

    2006-01-01

    The advantages of using phase-coded pulse compression technique for radio fuze systems are evaluated. With building mathematical models a matched filter has be en implemented successfully. Various simulations for pulse compression waveform coding were done to evaluate the performance of fuze system under noisy environment. The results of the simulation and the data analysis show that the phase-coded pulse compression gets a good result in the signal identification of the radio fuze with matched filter. Simultaneously, a suitable sidelobe suppression filter is established by simulation, the suppressed sidelobe level is acceptable to radio fuze application.

  6. Effects of selective and non-selective inhibitors of nitric oxide synthase on morphine- and endomorphin-1-induced analgesia in acute and neuropathic pain in rats.

    Science.gov (United States)

    Makuch, Wioletta; Mika, Joanna; Rojewska, Ewelina; Zychowska, Magdalena; Przewlocka, Barbara

    2013-12-01

    Nitric oxide (NO) has been reported to be involved in the mechanisms of pain generation throughout the nervous system. We examined the effects of intrathecally (i.t.) administered nitric oxide synthase (NOS) inhibitors on the antinociceptive effects of morphine and endomorphin-1 during acute pain and in chronic constriction injury (CCI)-exposed rats. We used N(G)-nitro-l-arginine methyl ester (l-NAME), a non-selective NOS inhibitor; 7-nitroindazole (7-NI) or 1-(2-trifluoromethyl-phenyl)-imidazole (TRIM), selective inhibitors of neuronal NOS (NOS1); and 1400W dihydrochloride, a selective inhibitor of inducible NOS (NOS2). Morphine (0.5-2.5 μg) and endomorphin-1 (2.5-20 μg) in acute pain and morphine (10-40 μg) and endomorphin-1 (5-20 μg) after CCI-injury were combined with NOS inhibitors. For acute pain, the ED50 for endomorphin-1 (7.1 μg) was higher than that of morphine (1.3 μg) in the tail-flick test. For neuropathic pain, the ED50 value for morphine was much higher (43.2 μg) than that of endomorphin-1 (9.2 μg) in von Frey test. NOS inhibitors slightly influenced pain thresholds in both pain models. Moreover, in neuropathic pain, the effects of morphine were more potentiated by L-NAME, TRIM, 7-NI and 1400W (12×, 8.6×, 4.1× and 5.3×, respectively) than were the effects of endomorphin-1 (2.7×, 4.3×, 3.4× and 2.1×, respectively) in the von Frey test. Minocycline which is known to enhance the efficiency of morphine in neuropathic pain, decreased the mRNA expression of NOS1 in the DRG and NOS2 and C1q in the spinal cord after CCI. Both NOS2 and IBA-1 protein levels in the spinal cord and NOS1, NOS2 and IBA1 protein levels in DRG decreased after minocycline administration. In conclusion, our results provide evidence that both neuronal and non-neuronal NOS/NO pathways contribute to the behavioural pain responses evoked by nerve injury. The NOS inhibitors regardless of the type of pain enhanced morphine antinociception and, to a lesser extent, altered the

  7. Therapeutic applications of selective and non-selective inhibitors of monoamine oxidase A and B that do not cause significant tyramine potentiation.

    Science.gov (United States)

    Youdim, Moussa B H; Weinstock, Marta

    2004-01-01

    The major side effect with the use of first generation of non selective monoamine oxidase (MAO) inhibitors as neuropsychiatric drugs was what became known as the "cheese reaction". Namely, potentiation of sympathomimetic activity of ingested tyramine present in cheese and other food stuff, resulting from its ability to release noradrenaline, when prevented from metabolism by MAO. The identification of two forms of MAO, termed types A and B and their selective irreversible inhibitors resolved some of this problems. However irreversible MAO-A inhibitors continue to induce a cheese reaction, whereas MAO-B inhibitors at their selective dosage did not and led to introduction of L-deprenyl (selegiline) as an anti-Parkinson drug, since dopamine is equally well metabolized by both enzyme forms. The cheese reaction is a consequence of inhibition of MAO-A, the enzyme responsible for metabolism of noradrenaline and serotonin, located in peripheral adrenergic neurons. The consequence of these findings were the development of reversible MAO-A inhibitors (RIMA), moclobemide and brofaromin, as antidepressants and possible anti-Parkinson activity, with limited tyramine potentiation, since the amine can displace the inhibitor from its binding site on the enzyme. It has always been deemed a greater pharmacological advantage to inhibit both forms of the enzymes to get the full functional activities of the amine neurotransmitters, and without inducing a "cheese reaction". This was not possible until recently, with the development of the novel cholinesterase-brain selective MAO-AB inhibitor, TV3326 (N-propargyl-(3R)-aminoidnan-5-yl-ethyl methylcarbamate hemitartiate), a carbamate derivative of the irreversible MAO-B inhibitor anti-Parkinson drug, rasagiline. This drug is a brain selective MAO-A and B inhibitor, with little inhibition of liver and small intestine enzymes. Pharmacologically it has limited tyramine potentiation, very similar to moclobemide and being a MAO-AB inhibitor it

  8. Effects of a non-selective TRPC channel blocker, SKF-96365, on melittin-induced spontaneous persistent nociception and inflammatory pain hypersensitivity

    Institute of Scientific and Technical Information of China (English)

    Jing Ding; Jia-Rui Zhang; Yan Wang; Chun-Li Li; Dan Lu; Su-Min Guan; Jun Chen

    2012-01-01

    Objective Melittin is the main peptide in bee venom and causes both persistent spontaneous nociception and pain hypersensitivity.Our recent studies indicated that both transient receptor potential (TRP) vanilloid receptor 1 (TRPV1) and canonical TRPs (TRPCs) are involved in mediating the melittin-induced activation of different subpopulations of primary nociceptive cells.Here,we further determined whether TRPC channels are involved in melittin-induced inflammatory nociceptive responses in behavioral assays.Methods The anti-nociceptive and anti-hyperalgesic effects of localized peripheral administration of three doses of the non-selective TRPC antagonist,SKF-96365 (1-{β-[3-(4-methoxyphenyl)propoxy]-4-methoxyphenyl}-1H-imidazole hydrochloride),were evaluated in melittin tests.Pain-related behaviors were rated by counting the number of paw flinches,and measuring paw withdrawal thermal latency (s) and paw withdrawl mechanical threshold (g),over a 1-h time-course.Results Localized peripheral SKF-96365 given before melittin prevented,and given after melittin significantly suppressed,the melittin-evoked persistent spontaneous nociception.Pre-blockade and post-suppression of activation of primary nociceptive activity resulted in decreased hypersensitivity to both thermal and mechanical stimuli applied to the primary injury site of the ipsilateral hindpaw,despite dose-effect differences between thermal and mechanical hyperalgesia.However,local administration of SKF-96365 into the contralateral hindpaw had no significant effect on any pain-associated behaviors.In addition,SKF-96365 had no effect on baseline threshold for either thermal or mechanical sensitivity under normal conditions.Conclusion Besides TRPV1,SKF-96365-sensitive TRPC channels might also be involved in the pathophysiological processing of melittin-induced inflammatory pain and hypersensitivity.Therapeutically,SKF-96365 is equally effective in preventing primary thermal and mechanical hyperalgesia as well as

  9. Differential effects of selective frankincense (Ru Xiang) essential oil versus non-selective sandalwood (Tan Xiang) essential oil on cultured bladder cancer cells: a microarray and bioinformatics study

    Science.gov (United States)

    2014-01-01

    cancer cell death. While frankincense essential oil elicited selective cancer cell death via NRF-2-mediated oxidative stress, sandalwood essential oil induced non-selective cell death via DNA damage and cell cycle arrest. PMID:25006348

  10. Optical and millimeter-wave radio seamless MIMO transmission based on a radio over fiber technology.

    Science.gov (United States)

    Kanno, Atsushi; Kuri, Toshiaki; Hosako, Iwao; Kawanishi, Tetsuya; Yoshida, Yuki; Yasumura, Yoshihiro; Kitayama, Ken-ichi

    2012-12-31

    Multi-input multi-output (MIMO) transmission of two millimeter-wave radio signals seamlessly converted from polarization-division-multiplexed quadrature-phase-shift-keying optical signals is successfully demonstrated, where a radio access unit basically consisting of only optical-to-electrical converters and a radio receiver performs total signal equalization of both the optical and the radio paths and demodulation with digital signal processing (DSP). Orthogonally polarized optical components that are directly converted to two-channel radio components can be demultiplexed and demodulated with high-speed DSP as in optical digital coherent detection. 20-Gbaud optical and radio seamless MIMO transmission provides a total capacity of 74.4 Gb/s with a forward error correction overhead of 7%.

  11. Joint radio and optical observations of the most radio-powerful intracloud lightning discharges

    Directory of Open Access Journals (Sweden)

    A. R. Jacobson

    2013-03-01

    Full Text Available The most radio-powerful intracloud lightning emissions are associated with a phenomenon variously called "narrow bipolar events" or "compact intracloud discharges". This article examines in detail the coincidence and timing relationship between, on the one hand, the most radio-powerful intracloud lightning events and, on the other hand, optical outputs (or lack thereof of the same discharge process. This is done, first, using coordinated very high frequency (VHF and optical observations from the FORTE satellite and, second, using coordinated sferic and all-sky optical observations from the Los Alamos Sferic Array. In both cases, it is found that the sought coincidences are exceedingly rare. Moreover, in the handful of coincidences between optical and intense radio emissions that have been identified, the radio emissions differ from their usual behavior, by being accompanied by approximately simultaneous "conventional" lightning radio emissions. It is implied that the most radio-powerful intracloud emission process essentially differs from ordinary incandescent lightning.

  12. 3C 57 as an Atypical Radio-Loud Quasar: Implications for the Radio-Loud/Radio-Quiet Dichotomy

    CERN Document Server

    Sulentic, J W; Marziani, P; del Olmo, A; Stirpe, G M; Zamfir, S; Plauchu-Frayn, I

    2015-01-01

    Lobe-dominated radio-loud (LD RL) quasars occupy a restricted domain in the 4D Eigenvector 1 (4DE1) parameter space which implies restricted geometry/physics/kinematics for this subclass compared to the radio-quiet (RQ) majority of quasars. We discuss how this restricted domain for the LD RL parent population supports the notion for a RQ-RL dichotomy among Type 1 sources. 3C 57 is an atypical RL quasar that shows both uncertain radio morphology and falls in a region of 4DE1 space where RL quasars are rare. We present new radio flux and optical spectroscopic measures designed to verify its atypical optical/UV spectroscopic behaviour and clarify its radio structure. The former data confirms that 3C 57 falls off the 4DE1 quasar "main sequence" with both extreme optical FeII emission (R_{FeII} ~ 1) and a large CIV 1549 profile blueshift (~ -1500 km/s). These parameter values are typical of extreme Population A sources which are almost always RQ. New radio measures show no evidence for flux change over a 50+ year ...

  13. Unified Schemes for Radio-loud AGN: Recent Results

    OpenAIRE

    Padovani, Paolo

    1997-01-01

    After briefly summarizing the main tenets of unified schemes of Active Galactic Nuclei, I review some recent results in the field of unification of radio-loud sources, both for the low-luminosity (BL Lacs and Fanaroff-Riley type I radio galaxies) and high-luminosity (radio quasars and Fanaroff-Riley type II radio galaxies) populations.

  14. 47 CFR 80.1153 - Station log and radio watches.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Station log and radio watches. 80.1153 Section... SERVICES STATIONS IN THE MARITIME SERVICES Voluntary Radio Installations General § 80.1153 Station log and radio watches. (a) Licensees of voluntary ships are not required to maintain radio station logs....

  15. Sending the right message : forty years of BBC Radio News

    NARCIS (Netherlands)

    Luscombe-Serlie, J.C.

    2012-01-01

    Radio is, compared to television and newspapers, an under-researched area in media studies. This research has looked at BBC Radio News in the period 1966-2008; it is a case study into the views of 43 (former) writers of the BBC Radio Newsroom and BBC Radio One. Interviews were conducted with practit

  16. Radio Path Prediction Software for Command and Control Scenario Developers

    Science.gov (United States)

    2006-06-01

    Microwave Experimenter’s Manual, 1990), ( ARRL Handbook for Radio Amateurs, 2001), (Saunders, 1999). Effective Isotropic Radiated Power (EIRP...receiver should have the same polarization for best performance. ( ARRL Handbook for Radio Amateurs, 2001), (McLarnon). Reflections and Delay...if” questions. 18 References ARRL Handbook for Radio Amateurs. Amateur Radio Relay League 2001. ARRL UHF/Microwave Experimenter’s Manual

  17. 47 CFR 2.107 - Radio astronomy station notification.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Radio astronomy station notification. 2.107....107 Radio astronomy station notification. (a) Pursuant to No. 1492 of Article 13 and Section F of Appendix 3 to the international Radio Regulations (Geneva, 1982), operators of radio astronomy stations...

  18. 77 FR 75946 - Radio Broadcasting Services; Dove Creek, CO

    Science.gov (United States)

    2012-12-26

    ... COMMISSION 47 CFR Part 73 . Radio Broadcasting Services; Dove Creek, CO AGENCY: Federal Communications... 47 CFR Part 73 Radio, Radio broadcasting. Federal Communications Commission. Nazifa Sawez, Assistant... Communications Commission proposes to amend 47 CFR Part 73 as follows: PART 73--RADIO BROADCAST SERVICES 1....

  19. 78 FR 37474 - Radio Broadcasting Services; Dove Creek, Colorado

    Science.gov (United States)

    2013-06-21

    ... COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Dove Creek, Colorado AGENCY: Federal Communications... CFR Part 73 Radio, Radio broadcasting. Federal Communications Commission. Nazifa Sawez, Chief, Audio... amends 47 CFR part 73 as follows: PART 73--RADIO BROADCAST SERVICES 0 1. The authority citation for...

  20. 78 FR 71557 - Radio Broadcasting Services; Tohatchi, New Mexico

    Science.gov (United States)

    2013-11-29

    ... COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Tohatchi, New Mexico AGENCY: Federal Communications... Radio, Radio broadcasting. Federal Communications Commission. Nazifa Sawez, Assistant Chief, Audio... proposes to amend 47 CFR part 73 as follows: PART 73--RADIO BROADCAST SERVICES 0 1. The authority...

  1. 47 CFR 1.83 - Applications for radio operator licenses.

    Science.gov (United States)

    2010-10-01

    ... this chapter. (b) Application filing procedures for commercial radio operator licenses are set forth in... file applications for commercial radio operator licenses is contained in the bulletin “Commercial Radio... 47 Telecommunication 1 2010-10-01 2010-10-01 false Applications for radio operator licenses....

  2. 47 CFR 20.9 - Commercial mobile radio service.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Commercial mobile radio service. 20.9 Section... COMMERCIAL MOBILE RADIO SERVICES § 20.9 Commercial mobile radio service. (a) The following mobile services shall be treated as common carriage services and regulated as commercial mobile radio...

  3. 49 CFR 220.45 - Radio communication shall be complete.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Radio communication shall be complete. 220.45... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD COMMUNICATIONS Radio and Wireless Communication Procedures § 220.45 Radio communication shall be complete. Any radio communication which is not fully understood...

  4. 75 FR 52872 - Radio Broadcasting Services; Blythe, CA

    Science.gov (United States)

    2010-08-30

    ... COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Blythe, CA AGENCY: Federal Communications Commission. ACTION: Final rule. SUMMARY: The Audio Division, at the request of Prescott Valley Radio Broadcasting... Congressional Review Act, see U.S.C. 801(a)(1)(A). List of Subjects in 47 CFR Part 73 Radio, Radio...

  5. 75 FR 82279 - Radio Broadcasting Services; Various Locations

    Science.gov (United States)

    2010-12-30

    ... COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Various Locations AGENCY: Federal Communications... Subjects in 47 CFR Part 73 Radio, Radio broadcasting. 0 As stated in the preamble, the Federal Communications Commission amends 47 CFR part 73 as follows: PART 73--RADIO BROADCASTING SERVICES 0 1....

  6. The radio structure of NGC 1275

    Energy Technology Data Exchange (ETDEWEB)

    Pedlar, A.; Ghataure, H.S.; Davies, R.D.; Harrison, B.A. (Nuffield Radio Astronomy Labs., Jodrell Bank (UK)); Perley, R.; Crane, P.C. (National Radio Astronomy Observatory, Socorro, NM. (USA)); Unger, S.W. (Royal Greenwich Observatory, Hailsham (UK))

    1990-10-01

    We present high dynamic range VLA and MERLIN images of NGC 1275 at wavelengths of 18, 22, 90 and 199 cm with angular resolutions ranging from 0.3 to 40 arcsec. Over the central 30 arcsec there is evidence for collimated ejection mainly in PA 160{sup o}. Outside this region the radio structure shows evidence of a sharp change in direction to approximately PA 235{sup o}, before merging into the 10-arcmin radio halo. On arcsec and arcmin angular scales, there is considerable asymmetry between the structure north and south of the active nucleus. We consider the radio source structure to be consistent with an asymmetrical Fanaroff-Riley type I source, with the jet collimation axis close to the line-of-sight. The radio 'halo' consists of the outer lobes of this structure. (author).

  7. Young Radio Pulsars in Galactic Globular Clusters

    CERN Document Server

    Boyles, Jason; Turk, Phil J; Mnatsakanov, Robert; Lynch, Ryan S; Ransom, Scott M; Freire, Paulo C; Belczynski, Khris

    2011-01-01

    Currently three isolated radio pulsars and one binary radio pulsar with no evidence of any previous recycling are known in 97 surveyed Galactic globular clusters. As pointed out by Lyne et al., the presence of these pulsars cannot be explained by core-collapse supernovae, as is commonly assumed for their counterparts in the Galactic disk. We apply a Bayesian analysis to the results from surveys for radio pulsars in globular clusters and find the number of potentially observable non-recycled radio pulsars present in all clusters to be -0.6. In this case, the potentially observable population of such young pulsars is 447^{+1420}_{-399} (the error bars give the 95% confidence interval) and their birth rate is 0.012^{+0.037}_{-0.010} pulsars per century. The mostly likely creation scenario to explain these pulsars is the electron capture supernova of a OMgNe white dwarf.

  8. Radio spectral index from NVSS and TGSS

    CERN Document Server

    Tiwari, Prabhakar

    2016-01-01

    We extract the radio spectral index, $\\alpha$, from the 541,195 common sources observed in 150 MHz TIFR GMRT Sky Survey (TGSS) and 1.4 GHz NRAO VLA Sky Survey (NVSS). These catalogs cover about $80\\%$ of the sky and represent the largest radio population. We confirm the steepening of $\\alpha$ with increasing flux density. Further, we observe an increase in $\\alpha$ with source size (TGSS measured) saturating araound size 50 arcsec to $0.83\\pm0.01$. From this saturated value, we constrain the electron energy injection spectral index, $\\gamma$, and the fractional contribution of supernova remnants to the total radio flux. Our results indicate relatively low $\\gamma \\sim 1.8-1.9$ and a large supernova remnants contribution ($\\sim 15-25\\%$). For very compact sources the convection and the thermal radio emission are likely to be important.

  9. Reconfigurable, Cognitive Software Defined Radio Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Intelligent Automation Inc, (IAI) is currently developing a software defined radio (SDR) platform that can adaptively switch between different modes of operation for...

  10. Reconfigurable, Cognitive Software Defined Radio Project

    Data.gov (United States)

    National Aeronautics and Space Administration — IAI is actively developing Software Defined Radio platforms that can adaptively switch between different modes of operation by modifying both transmit waveforms and...

  11. Department of design and radio production

    Directory of Open Access Journals (Sweden)

    Iu. V. Mykhatskyi

    1998-09-01

    Full Text Available Department of radio production in the 100 year anniversary of Kiev Polytechnic Institute celebrates 30 years - it was launched as part of the radio department since September 1968. Fourth at the Faculty Department was created by the Council with the support of faculty "old" departments. Department saw the feasibility of establishing another department, referring to the need to improve the content and organization of educational process specialties "Design and Production of Radio" according to the needs of industry, designers technologists features a complicated radioaparatobuduvanni required at the time their number increased. in the order of the Minister of Higher and Secondary Special Education of Ukraine, organization department, its functions and tasks was determined as a function of the Department profiling responsible for setting training educational work among the students of specialty "Design and Production of Radio" and the quality of training.

  12. Radio imaging of launch vehicles and payloads

    Science.gov (United States)

    Rowe, Harrison E.

    1988-01-01

    The detection and tracing of rockets and payloads by microwave or millimeter-wave passive radio temperature measurements is analytically studied using radio astronomical techniques. Radio image reconstruction is performed by spatial filtering of multiple, simultaneous, equally-spaced radio brightness measurements. Both Wiener filtering for complex images and matched filtering for separated, point targets are considered. Output SNR is found to improve as receiver integration time increases, but blurring due to image motion places a limit on receiver integration time with fixed spatial filters. Little difference is found between an antenna with tapered illumination and low sidelobes and a maximum gain antenna with high sidelobes for interpolation. Several numerical examples are presented in order to give a preliminary indication of the magnitudes of system parameters.

  13. Detecting the cosmic web with radio surveys

    CERN Document Server

    Vazza, F; Gheller, C; Ferrari, C; Bonafede, A

    2016-01-01

    We study the challenges to detect the cosmic web at radio wavelengths with state-of-the-art cosmological simulations of extragalactic magnetic fields. The incoming generation of radio surveys operating at low frequency, like LOFAR, SKA-LOW and MWA will have the best chance to detect the large-scale, low surface brightness emission from the shocked cosmic web. The detected radio emission will enable to constrain the average magnetisation level of the gas in filaments and the acceleration efficiency of electrons by strong shocks. In case of detections, through statistical modelling (e.g. correlation functions) it will be possible to discriminate among competing scenarios for the magnetisation of large-scale structures (i.e. astrophysical versus primordial scenarios), making radio surveys an important probe of cosmic magnetogenesis.

  14. Distortion mitigation in cognitive radio receivers

    NARCIS (Netherlands)

    Mahrof, Dlovan Hoshiar

    2015-01-01

    The exponential increase of wireless communication increasingly leads to spectrum congestion. Attempts are being made to increase RF spectrum utilization efficiency by introducing Cognitive Radio (CR) concept. A CR tries to intelligently solve the congestion problem via Dynamic Spectrum Acce

  15. Observations of Radio Giant Pulses with GAVRT

    CERN Document Server

    Jones, Glenn

    2015-01-01

    Radio giant pulses provide a unique opportunity to study the pulsar radio emission mechanism in exquisite detail. Previous studies have revealed a wide range of properties and phenomena, including extraordinarily high brightness temperatures, sub-nanosecond emission features, and banded dynamic spectra. New measurements of giant pulse characteristics can help guide and test theoretical emission models. To this end, an extensive observation campaign has begun which will provide more than 500 hours on the Crab with a 34-meter antenna located in California, USA. The observations are being done as part of an educational outreach program called the Goldstone-Apple Valley Radio Telescope (GAVRT). This antenna has a novel wide bandwidth receiver which provides up to 8 GHz of instantaneous bandwidth in the range of 2.5 to 14 GHz. These observations will provide detailed information about the variability, amplitude distribution, and detailed frequency structure of radio giant pulses. In addition, a database of pulses ...

  16. Radio VLBI and the quantum interference paradox

    CERN Document Server

    Singal, Ashok K

    2016-01-01

    We address here the question of interference of radio signals from astronomical sources like distant quasars, in a very long baseline interferometer (VLBI), where two (or more) distantly located radio telescopes (apertures), receive simultaneous signal from the sky. In an equivalent optical two-slit experiment, it is generally argued that for the photons involved in the interference pattern on the screen, it is not possible, even in principle, to ascertain which of the two slits a particular photon went through. It is argued that any procedure to ascertain this destroys the interference pattern. But in the case of the modern radio VLBI, it is a routine matter to record the phase and amplitude of the voltage outputs from the two radio antennas on a recording media separately and then do the correlation between the two recorded signals later in an offline manner. Does this not violate the quantum interference principle? We provide a resolution of this problem here.

  17. Goldstone Apple Valley Radio Telescope Project.

    Science.gov (United States)

    Ibe, Mary; MacLaren, Dave

    2003-01-01

    Describes the Goldstone Apple Valley Radio Telescope (GAVRT) project as a way of teaching astronomy concepts to middle school students. The project provides students opportunities to work with professional scientists. (SOE)

  18. Radio Astronomical Polarimetry and the Lorentz Group

    CERN Document Server

    Britton, M C

    1999-01-01

    In radio astronomy the polarimetric properties of radiation are often modified during propagation and reception. Effects such as Faraday rotation, receiver cross-talk, and differential amplification act to change the state of polarized radiation. A general description of such transformations is useful for the investigation of these effects and for the interpretation and calibration of polarimetric observations. Such a description is provided by the Lorentz group, which is intimately related to the transformation properties of polarized radiation. In this paper the transformations that commonly arise in radio astronomy are analyzed in the context of this group. This analysis is then used to construct a model for the propagation and reception of radio waves. The implications of this model for radio astronomical polarimetry are discussed.

  19. Radio Band Observations of Blazar Variability

    CERN Document Server

    Aller, Margo F; Hughes, Philip A

    2010-01-01

    The properties of blazar variability in the radio band are studied using the unique combination of temporal resolution from single dish monitoring and spatial resolution from VLBA imaging; such measurements, now available in all four Stokes parameters, together with theoretical simulations, identify the origin of radio band variability and probe the characteristics of the radio jet where the broadband blazar emission originates. Outbursts in total flux density and linear polarization in the optical-to-radio bands are attributed to shocks propagating within the jet spine, in part based on limited modeling invoking transverse shocks; new radiative transfer simulations allowing for shocks at arbitrary angle to the flow direction confirm this picture by reproducing the observed centimeter-band variations observed more generally, and are of current interest since these shocks may play a role in the gamma-ray flaring detected by Fermi. Recent UMRAO multifrequency Stokes V studies of bright blazars identify the spec...

  20. Reconfigurable Power-Aware EVA Radio Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced Extra Vehicular Activity (EVA) radio system is a pivotal technology for the successful support of the International Space Station beyond 2020 and future...

  1. The Velocity Distribution of Isolated Radio Pulsars

    CERN Document Server

    Arzoumanian, Z; Cordes, J M

    2002-01-01

    (Abridged) We infer the velocity distribution of radio pulsars by modelling their birth, evolution, and detection in large-scale 0.4 GHz pulsar surveys, and by comparing model distributions of measurable pulsar properties with survey data using a likelihood function. We test models that characterize a population's birth rate, luminosity, shutoff of radio emission, birth locations, and birth velocities. We infer that the radio beam luminosity (i) is comparable to the energy flux of relativistic particles in models for spin-driven magnetospheres, signifying that radio emission losses reach nearly 100% for the oldest pulsars; and (ii) scales approximately as sqrt(Edot) which, in magnetosphere models, is proportional to the voltage drop available for acceleration of particles. We find that a two-component velocity distribution with characteristic velocities of 90 km/s and 500 km/s is greatly preferred to any one-component distribution. We explore some consequences of the preferred birth velocity distribution: (i)...

  2. Radio broadcasting for sustainable development in southern ...

    African Journals Online (AJOL)

    Patrick O. Waeber and Yvonne Orengo

    2008-12-03

    Dec 3, 2008 ... A convergence between the two movements aimed at promoting environmental, social and ..... 80 members (men and women) of eight radio Listening Groups who had been ...... traditional media to the Internet. FAO. Rome.

  3. Radio Supernovae in the Local Universe

    CERN Document Server

    Kamble, Atish; Berger, Edo; Zauderer, Ashley; Chakraborti, Sayan; Williams, Peter

    2014-01-01

    In the last three decades, about 50 radio supernovae have been detected as a result of targeted searches of optically discovered supernovae in the local universe. Despite this relatively small number some diversity among them has already been identified which is an indication of the underlying richness of radio supernovae waiting to be discovered. For example, comparison of star formation and supernova discovery rate imply that as many as half of the supernovae remain undetected in the traditional optical searches, either because of intrinsic dimness or due to dust obscuration. This has far reaching consequences to the models of stellar and galaxy evolution. A radio sky survey would be ideal to uncover larger supernova population. Transient radio sky would benefit significantly from such a survey. With the advent of advanced gravitational wave detectors a new window is set to open on the local Universe. Localization of these gravitational detectors is poor to identify electromagnetic counterparts of the gravi...

  4. Cognitive Radio Networks From Theory to Practice

    CERN Document Server

    Khattab, Ahmed; Bayoumi, Magdy

    2013-01-01

    This book describes a communication paradigm that could shape the future of wireless communication networks, Opportunistic Spectrum Access (OSA) in Cognitive Radio Networks (CRN).  While several theoretical OSA approaches have been proposed, they are challenged by the practical limitations of cognitive radios: the key enabling technology of OSA.  This book presents an unprecedented formulation of the OSA problem in CNR that takes into account the practical limitations encountered due to existing technologies. Based on such a problem formulation, this book presents a framework and protocol details implementing the analytically-optimized solution of this problem. Unlike the state-of-the-art of CRN implementations that typically target software define radios which are not suitable for real systems, this book describes the implementation of distributed OSA, using practical radio transceiver technologies. It provides a thorough characterization of the gains available to theoretical OSA approaches if the practica...

  5. Radio Afterglows of Gamma Ray Bursts

    Science.gov (United States)

    Resmi, Lekshmi

    2017-09-01

    This review focuses on the physics of Gamma Ray Bursts probed through their radio afterglow emission. Even though radio band is the least explored of the afterglow spectrum, it has played an important role in the progress of GRB physics, specifically in confirming the hypothesized relativistic effects. Currently radio astronomy is in the beginning of a revolution. The high sensitive Square Kilometer Array (SKA) is being planned, its precursors and pathfinders are about to be operational, and several existing instruments are undergoing upgradation. Thus, the afterglow results from detection statistics and follow up programs are expected to improve in the coming years. We list a few avenues unique to radio band which if explored to full potential have the promise to greatly contribute to the future of GRB physics.

  6. Software Defined Multiband EVA Radio Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of this research is to propose a reliable, lightweight, programmable, multi-band, multi-mode, miniaturized frequency-agile EVA software defined radio...

  7. Software Defined Multiband EVA Radio Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of Phase 2 is to build a reliable, lightweight, programmable, multi-mode, miniaturized EVA Software Defined Radio (SDR) that supports data telemetry,...

  8. Spatial Identification of Passive Radio Frequency Identification Tags Using Software Defined Radios

    Science.gov (United States)

    2012-03-01

    of 56 MBytes per second [20]. All communications between the main board and GNU Radio on the host PC take place through this controller. More recent...Digital AGC and Data signal from the main board are both determined by the Python code generated by GNU Radio on the host PC. This local oscillator signal...running Ubuntu 10.10 and GNU Radio , a USRP1 SDR with a Flex 900 daughter card and two Alien 9611-CR antennas. The GNU Radio installation has been

  9. Phenomenology of Neptune's radio emissions observed by the Voyager planetary radio astronomy experiment

    Science.gov (United States)

    Pedersen, B. M.; Lecacheux, A.; Zarka, P.; Aubier, M. G.; Kaiser, M. L.; Desch, M. D.

    1992-01-01

    The Neptune flyby in 1989 added a new planet to the known number of magnetized planets generating nonthermal radio emissions. We review the Neptunian radio emission morphology as observed by the planetary radio astronomy experiment on board Voyager 2 during a few weeks before and after closest approach. We present the characteristics of the two observed recurrent main components of the Neptunian kilometric radiation, i.e., the 'smooth' and the 'bursty' emissions, and we describe the many specific features of the radio spectrum during closest approach.

  10. DARC servis konvencionalne FM radio-difuzije / DARC service conventional FM radio broadcasting

    Directory of Open Access Journals (Sweden)

    Mladen Manjak

    2006-07-01

    Full Text Available Konvencionalna FM radio-difuzija može ponuditi dodatne servise uz pomoć podnosioca smještenih u slobodnom dijelu osnovnog opsega multipleksiranog signala. U radu su prikazane osnovne karakteristike DARC servisa FM radio-difuzije i njegove moguće primjene. / Conventional FM radio broadcasting can offer additional services by means of a subcarrier placed in a clear part of the beseband multiplex signal. This paper contains elementary characteristics of DARC service conventional FM radio broadcasting and possible applications.

  11. Voyager-Jupiter radio science data papers

    Science.gov (United States)

    Levy, G. S.; Wood, G. E.

    1980-01-01

    The reduction and interpretation of the radio science data from the Voyager 1 and 2 encounters of the planet Jupiter and its satellites resulted in the preparation of several papers for publication in the special Voyager-Jupiter issue of the Journal of Geophysical Research. The radio science and tracking systems of the Deep Space Network provide the data which makes this research possible. This article lists submitted papers by title, with their authors and with abstracts of their contents.

  12. Big Data Challenges for Large Radio Arrays

    Science.gov (United States)

    Jones, Dayton L.; Wagstaff, Kiri; Thompson, David; D'Addario, Larry; Navarro, Robert; Mattmann, Chris; Majid, Walid; Lazio, Joseph; Preston, Robert; Rebbapragada, Umaa

    2012-01-01

    Future large radio astronomy arrays, particularly the Square Kilometre Array (SKA), will be able to generate data at rates far higher than can be analyzed or stored affordably with current practices. This is, by definition, a "big data" problem, and requires an end-to-end solution if future radio arrays are to reach their full scientific potential. Similar data processing, transport, storage, and management challenges face next-generation facilities in many other fields.

  13. First Colombian Solar Radio Interferometer: current stage

    Science.gov (United States)

    Guevara Gómez, J. C.; Martínez Oliveros, J. C.; Calvo-Mozo, B.

    2017-10-01

    Solar radio astronomy is a fast developing research field in Colombia. Here, we present the scientific goals, specifications and current state of the First Colombian Solar Radio Interferometer consisting of two log-periodic antennas covering a frequency bandwidth op to 800 MHz. We describe the importance and benefits of its development to the radioastronomy in Latin America and its impact on the scientific community and general public.

  14. Envelope Soliton in Solar Radio Emission

    Institute of Scientific and Technical Information of China (English)

    WANG De-Yu; Wangde; G. P. Chernov

    2000-01-01

    Several envelope soliton fine structures have been observed in solar radio metric-wave emission. We present amodel of 1ongitudinal modulational instability to explain these fine structures. It is found that this instability canonly occur in the condition of sound velocity being larger than Alfven velocity in corona. Therefore, the envelopesoliton fine structures should display in the coronal region with high temperature and low magnetic field, whichcorresponds to the solar radio emission in the region of meter and decameter wavelength.

  15. Cognitive Radio Networks for Tactical Wireless Communications

    Science.gov (United States)

    2014-12-01

    APs work as wireless routers and form a wireless backbone network. The MSs can either access the BSs/APs directly, or use other MSs as multi-hop...Cognitive radio networks for tactical wireless communications Helen Tang; Susan Watson DRDC – Ottawa Research Centre Defence Research and...Development Canada Scientific Report DRDC-RDDC-2014-R185 December 2014 Cognitive radio networks for tactical wireless communications Helen Tang

  16. Big Data Challenges for Large Radio Arrays

    Science.gov (United States)

    Jones, Dayton L.; Wagstaff, Kiri; Thompson, David; D'Addario, Larry; Navarro, Robert; Mattmann, Chris; Majid, Walid; Lazio, Joseph; Preston, Robert; Rebbapragada, Umaa

    2012-01-01

    Future large radio astronomy arrays, particularly the Square Kilometre Array (SKA), will be able to generate data at rates far higher than can be analyzed or stored affordably with current practices. This is, by definition, a "big data" problem, and requires an end-to-end solution if future radio arrays are to reach their full scientific potential. Similar data processing, transport, storage, and management challenges face next-generation facilities in many other fields.

  17. Gravitational wave astronomy with radio galaxy surveys

    OpenAIRE

    Raccanelli, Alvise

    2016-01-01

    In the next decade, new astrophysical instruments will deliver the first large-scale maps of gravitational waves and radio sources. Therefore, it is timely to investigate the possibility to combine them to provide new and complementary ways to study the Universe. Using simulated catalogues appropriate to the planned surveys, it is possible to predict measurements of the cross-correlation between radio sources and GW maps and the effects of a stochastic gravitational wave background on galaxy ...

  18. Status of Radio Ice Cherenkov Experiment (RICE)

    CERN Document Server

    Allen, C; Besson, D; Frichter, G; Kotov, S A; Kravchenko, I V; McKay, D; Miller, T; Piccirillo, L; Ralston, J P; Seckel, D; Seunarine, S; Spiczak, G M

    1997-01-01

    RICE is designed to detect ultrahigh energy (>100 TeV) neutrinos from astrophysical sources. It will consist of an array of compact radio (100 to 1000 MHz) receivers buried in ice at the South Pole. During the 1995-96 and 1996-97 austral summers, several receivers transmitters were deployed in bore holes drilled for the AMANDA project, at depths of 141 to 260 m. This was the first in situ test of radio receivers in deep ice for neutrino astronomy.

  19. Expanded radio art as PhD practice

    OpenAIRE

    Hall, M.

    2015-01-01

    Radio After Radio: Redefining Radio Art in the Light of New Media Technology through Expanded Practice is the title of my PhD practice based research. This paper focuses on the extended boundaries of radio art, considering how radio art might be defined in relation to sound art, music, and media art. Mapping the shifting parameters of radio art in the digital era has prompted a consideration of how radio can be seen to be moving from being a predominantly shared "live" event to one consumed "...

  20. Radio flares from gamma-ray bursts

    CERN Document Server

    Kopac, D; Kobayashi, S; Virgili, F J; Harrison, R; Japelj, J; Guidorzi, C; Melandri, A; Gomboc, A

    2015-01-01

    We present predictions of centimeter and millimeter radio emission from reverse shocks in the early afterglows of gamma-ray bursts with the goal of determining their detectability with current and future radio facilities. Using a range of GRB properties, such as peak optical brightness and time, isotropic equivalent gamma-ray energy and redshift, we simulate radio light curves in a framework generalized for any circumburst medium structure and including a parametrization of the shell thickness regime that is more realistic than the simple assumption of thick- or thin-shell approximations. Building on earlier work by Mundell et al. (2007) and Melandri et al. (2010) in which the typical frequency of the reverse shock was suggested to lie at radio, rather than optical wavelengths at early times, we show that the brightest and most distinct reverse-shock radio signatures are detectable up to 0.1 -- 1 day after the burst, emphasizing the need for rapid radio follow-up. Detection is easier for bursts with later opt...

  1. Radio-flaring Ultracool Dwarf Population Synthesis

    Science.gov (United States)

    Route, Matthew

    2017-08-01

    Over a dozen ultracool dwarfs (UCDs), low-mass objects of spectral types ≥M7, are known to be sources of radio flares. These typically several-minutes-long radio bursts can be up to 100% circularly polarized and have high brightness temperatures, consistent with coherent emission via the electron cyclotron maser operating in approximately kilogauss magnetic fields. Recently, the statistical properties of the bulk physical parameters that describe these UCDs have become described adequately enough to permit synthesis of the population of radio-flaring objects. For the first time, I construct a Monte Carlo simulator to model the population of these radio-flaring UCDs. This simulator is powered by Intel Secure Key (ISK), a new processor technology that uses a local entropy source to improve random number generation that has heretofore been used to improve cryptography. The results from this simulator indicate that only ∼5% of radio-flaring UCDs within the local interstellar neighborhood (radio-flaring fraction and suggest that the observed behavior is likely a result of several factors. The performance of ISK as compared to other pseudorandom number generators is also evaluated, and its potential utility for other astrophysical codes is briefly described.

  2. Radio-quiet Gamma-ray Pulsars

    Science.gov (United States)

    Lin, Lupin Chun-Che

    2016-09-01

    A radio-quiet γ-ray pulsar is a neutron star that has significant γ-ray pulsation but without observed radio emission or only limited emission detected by high sensitivity radio surveys. The launch of the Fermi spacecraft in 2008 opened a new epoch to study the population of these pulsars. In the 2nd Fermi Large Area Telescope catalog of γ-ray pulsars, there are 35 (30 % of the 117 pulsars in the catalog) known samples classified as radio-quiet γ-ray pulsars with radio flux density (S1400) of less than 30 μJy. Accompanying the observations obtained in various wavelengths, astronomers not only have the opportunity to study the emitting nature of radio-quiet γ-ray pulsars but also have proposed different models to explain their radiation mechanism. This article will review the history of the discovery, the emission properties, and the previous efforts to study pulsars in this population. Some particular cases known as Geminga-like pulsars (e.g., PSR J0633+1746, PSR J0007+7303, PSR J2021+4026, and so on) are also specified to discuss their common and specific features.

  3. HI absorption in nearby compact radio galaxies

    Science.gov (United States)

    Glowacki, M.; Allison, J. R.; Sadler, E. M.; Moss, V. A.; Curran, S. J.; Musaeva, A.; Deng, C.; Parry, R.; Sligo, M. C.

    2017-01-01

    HI absorption studies yield information on both AGN feeding and feedback processes. This AGN activity interacts with the neutral gas in compact radio sources, which are believed to represent the young or recently re-triggered AGN population. We present the results of a survey for HI absorption in a sample of 66 compact radio sources at 0.040 100 km s-1) features, indicative of disturbed gas kinematics. Such broad, shallow and offset features are also found within low-excitation radio galaxies which is attributed to disturbed circumnuclear gas, consistent with early-type galaxies typically devoid of a gas-rich disk. Comparing mid-infrared colours of our galaxies with HI detections indicates that narrow and deep absorption features are preferentially found in late-type and high-excitation radio galaxies in our sample. These features are attributed to gas in galactic disks. By combining XMM-Newton archival data with 21-cm data, we find support that absorbed X-ray sources may be good tracers of HI content within the host galaxy. This sample extends previous HI surveys in compact radio galaxies to lower radio luminosities and provides a basis for future work exploring the higher redshift universe.

  4. The fundamental plane for radio magnetars

    CERN Document Server

    Rea, Nanda; Torres, Diego F; Turolla, Roberto

    2012-01-01

    High magnetic fields are a distinguishing feature of neutron stars and the existence of sources (the soft gamma repeaters and the anomalous X-ray pulsars) hosting an ultra-magnetized neutron star (or magnetar) has been recognized in the past few decades. Magnetars are believed to be powered by magnetic energy and not by rotation, as with normal radio pulsars. Until recently, the radio quietness and magnetic fields typically above the quantum critical value (Bq~4.4x10^{13} G), were among the characterizing properties of magnetars. The recent discovery of radio pulsed emission from a few of them, and of a low dipolar magnetic field soft gamma repeater, weakened further the idea of a clean separation between normal pulsars and magnetars. In this Letter we show that radio emission from magnetars might be powered by rotational energy, similarly to what occurs in normal radio pulsars. The peculiar characteristics of magnetars radio emission should be traced in the complex magnetic geometry of these sources. Further...

  5. Radio Source Morphology: 'nature or nuture'?

    Science.gov (United States)

    Banfield, Julie; Emonts, Bjorn; O'Sullivan, Shane

    2012-10-01

    Radio sources, emanating from supermassive black-holes in the centres of active galaxies, display a large variety of morphological properties. It is a long-standing debate to what extent the differences between various types of radio sources are due to intrinsic properties of the central engine (`nature') or due to the properties of the interstellar medium that surrounds the central engine and host galaxy (`nurture'). Settling this `nature vs. nurture' debate for nearby radio galaxies, which can be studied in great detail, is vital for understanding the properties and evolution of radio galaxies throughout the Universe. We propose to observe the radio galaxy NGC 612 where previous observations have detected the presence of a large-scale HI bridge between the host galaxy and a nearby galaxy NGC 619. We request a total of 13 hrs in the 750m array-configuration to determine whether or not the 100 kpc-scale radio source morphology is directly related to the intergalactic distribution of neutral hydrogen gas.

  6. Scaling down: local radio in India.

    Science.gov (United States)

    Anjaneyulu, K

    1989-01-01

    All India Radio (AIR) is one of the world's largest national radio networks. In the past 5 years, AIR has been experimenting with the idea of local radio stations. The governmental view of local radio is one that supports the idea of a close association with the hub of the community. It also believes that the radio station should act as a "mouthpiece" of the community. A large number of local programs are field-based. Access programs, service programs, and specific programs concerning family welfare, national integration, communal harmony and others relevant to the local broadcast area are produced. Community service broadcasts, the role of a local station as a mediator between local factions and access programs are further discussed. The experiences and development of the 1st local station at Nagercoil in the southern Indian state of Tamilnadu is discussed in detail. The greatest attribute of local radio is that it works directly with and is often directly controlled by the people it is designed to serve.

  7. Cognitive Radio — Genetic Algorithm Approach

    Science.gov (United States)

    Reddy, Y. B.

    2005-03-01

    Cognitive Radio (CR) is relatively a new technology, which intelligently detects a particular segment of the radio spectrum currently in use and selects unused spectrum quickly without interfering the transmission of authorized users. Cognitive Radios can learn about current use of spectrum in their operating area, make intelligent decisions, and react to immediate changes in the use of spectrum by other authorized users. The goal of CR technology is to relieve radio spectrum overcrowding, which actually translates to a lack of access to full radio spectrum utilization. Due to this adaptive behavior, the CR can easily avoid the interference of signals in a crowded radio frequency spectrum. In this research, we discuss the possible application of genetic algorithms (GA) to create a CR that can respond intelligently in changing and unanticipated circumstances and in the presence of hostile jammers and interferers. Genetic algorithms are problem solving techniques based on evolution and natural selection. GA models adapt Charles Darwin's evolutionary theory for analysis of data and interchanging design elements in hundreds of thousands of different combinations. Only the best-performing combinations are permitted to survive, and those combinations "reproduce" further, progressively yielding better and better results.

  8. Astrophysical results of the Mauritius radio telescope

    Science.gov (United States)

    Somanah, R.; Issur, N.; Oozeer, N.

    2013-04-01

    One of the first scientific justifications of building the Mauritius Radio Telescope (hereafter referred to as MRT) was to complement the Cambridge 6C survey, which is a radio map of most of the northern sky at 150 MHz [1]; the MRT would then be the equivalent of the 6C survey for the southern sky and together we would obtain a whole sky radio map at 150 MHz. When the MRT was built, there were no radio surveys of the southern sky at frequencies less than 408 MHz; the frequency of 150 MHz was also chosen to complement the other radio surveys of the southern sky, which have been done at higher frequencies. Furthermore low radio frequencies like 150 MHz are bound to see new sources that would have been missed at higher frequencies due to the form of their spectra. Interesting features of resolved objects can also be studied in more details. In this paper, a brief description of the MRT will be made as well as the observations and imaging with the MRT data, and some astrophysical results obtained since its commissioning in 1992 (20 years of existence this year 2012).

  9. Optically Faint Radio Sources: Reborn AGN?

    CERN Document Server

    Filho, Mercedes E; Lobo, Catarina; Antón, Sonia

    2011-01-01

    We have discovered a number of relatively strong radio sources in the field-of-view of SDSS galaxy clusters which present no optical counterparts down to the magnitude limits of the SDSS. The optically faint radio sources appear as double-lobed or core-jet objects on the FIRST radio images and have projected angular sizes ranging from 0.5 to 1.0 arcmin. We have followed-up these sources with near-infrared imaging using the wide-field imager HAWK-I on the VLT. K_s-band emitting regions, about 1.5 arcsec in size and coincident with the centers of the radio structures, were detected in all the sources, with magnitudes in the range 17-20 mag. We have used spectral modelling to characterize the sample sources. In general, the radio properties are similar to those observed in 3CRR sources but the optical-radio slopes are consistent with moderate to high redshift (z<4) gigahertz-peaked spectrum sources. Our results suggest that these unusual objects are galaxies whose black hole has been recently re-ignited but r...

  10. Realistic Radio Communications in Pilot Simulator Training

    Science.gov (United States)

    Burki-Cohen, Judith; Kendra, Andrew J.; Kanki, Barbara G.; Lee, Alfred T.

    2000-01-01

    Simulators used for total training and evaluation of airline pilots must satisfy stringent criteria in order to assure their adequacy for training and checking maneuvers. Air traffic control and company radio communications simulation, however, may still be left to role-play by the already taxed instructor/evaluators in spite of their central importance in every aspect of the flight environment. The underlying premise of this research is that providing a realistic radio communications environment would increase safety by enhancing pilot training and evaluation. This report summarizes the first-year efforts of assessing the requirement and feasibility of simulating radio communications automatically. A review of the training and crew resource/task management literature showed both practical and theoretical support for the need for realistic radio communications simulation. A survey of 29 instructor/evaluators from 14 airlines revealed that radio communications are mainly role-played by the instructor/evaluators. This increases instructor/evaluators' own workload while unrealistically lowering pilot communications load compared to actual operations, with a concomitant loss in training/evaluation effectiveness. A technology review searching for an automated means of providing radio communications to and from aircraft with minimal human effort showed that while promising, the technology is still immature. Further research and the need for establishing a proof-of-concept are also discussed.

  11. The reproducible radio outbursts of SS Cygni

    CERN Document Server

    Russell, T D; Sivakoff, G R; Altamirano, D; O'Brien, T J; Page, K L; Templeton, M R; Koerding, E G; Knigge, C; Rupen, M P; Fender, R P; Heinz, S; Maitra, D; Markoff, S; Migliari, S; Remillard, R A; Russell, D M; Sarazin, C L; Waagen, E O

    2016-01-01

    We present the results of our intensive radio observing campaign of the dwarf nova SS Cyg during its 2010 April outburst. We argue that the observed radio emission was produced by synchrotron emission from a transient radio jet. Comparing the radio light curves from previous and subsequent outbursts of this system (including high-resolution observations from outbursts in 2011 and 2012) shows that the typical long and short outbursts of this system exhibit reproducible radio outbursts that do not vary significantly between outbursts, which is consistent with the similarity of the observed optical, ultraviolet and X-ray light curves. Contemporaneous optical and X-ray observations show that the radio emission appears to have been triggered at the same time as the initial X-ray flare, which occurs as disk material first reaches the boundary layer. This raises the possibility that the boundary region may be involved in jet production in accreting white dwarf systems. Our high spatial resolution monitoring shows th...

  12. Radio Planetary Nebulae in the Magellanic Clouds

    CERN Document Server

    Filipović, M D; Reid, W A; Payne, J L; Parker, Q A; Crawford, E J; Bojičić, I S; De Horta, A Y; Hughes, A; Dickel, J; Stootman, F

    2009-01-01

    We report the extragalactic radio-continuum detection of 15 planetary nebulae (PNe) in the Magellanic Clouds (MCs) from recent Australia Telescope Compact Array+Parkes mosaic surveys. These detections were supplemented by new and high resolution radio, optical and IR observations which helped to resolve the true nature of the objects. Four of the PNe are located in the Small Magellanic Cloud (SMC) and 11 are located in the Large Magellanic Cloud (LMC). Based on Galactic PNe the expected radio flux densities at the distance of the LMC/SMC are up to ~2.5 mJy and ~2.0 mJy at 1.4 GHz, respectively. We find that one of our new radio PNe in the SMC has a flux density of 5.1 mJy at 1.4 GHz, several times higher than expected. We suggest that the most luminous radio PN in the SMC (N S68) may represent the upper limit to radio peak luminosity because it is ~3 times more luminous than NGC 7027, the most luminous known Galactic PN. We note that the optical diameters of these 15 MCs PNe vary from very small (~0.08 pc or ...

  13. Abell 1033: birth of a radio phoenix

    CERN Document Server

    de Gasperin, F; van Weeren, R J; Dawson, W A; Brüggen, M; Bonafede, A; Simionescu, A

    2015-01-01

    Extended steep-spectrum radio emission in a galaxy cluster is usually associated with a recent merger. However, given the complex scenario of galaxy cluster mergers, many of the discovered sources hardly fit into the strict boundaries of a precise taxonomy. This is especially true for radio phoenixes that do not have very well defined observational criteria. Radio phoenixes are aged radio galaxy lobes whose emission is reactivated by compression or other mechanisms. Here, we present the detection of a radio phoenix close to the moment of its formation. The source is located in Abell 1033, a peculiar galaxy cluster which underwent a recent merger. To support our claim, we present unpublished Westerbork Synthesis Radio Telescope and Chandra observations together with archival data from the Very Large Array and the Sloan Digital Sky Survey. We discover the presence of two sub-clusters displaced along the N-S direction. The two sub-clusters probably underwent a recent merger which is the cause of a moderately per...

  14. Authentication of Primary User in Cognitive Radio

    Directory of Open Access Journals (Sweden)

    Mr. Sudesh Gupta

    2012-03-01

    Full Text Available Cognitive Radio (CR or soft ware defined radio is a new concept for maximizing the utilization of the radio spectrum. The CR can sense the unused frequency spectrum at any time from the wide range of wireless radio spectrum. This gives the efficient use of radio resources. In cognitive radio environment, a primary licensed user (PU can share spectrum availability information with a secondary user, the secondary user will then be able to access available frequency spectrum. However, a secondary user should always need to verify the authenticity of the spectrum occupancy information whether it comes from the authentic primary users. Without the verification, a malicious user can give false information about the spectrum occupancy. This can result interference to the primary users and minimize available spectrum for the secondary usage. In this paper, we have develop an efficient technique to verify the source of the spectrum occupancy information is to be from the authentic primary user , by doing this we are maximizing the spectrum utilization efficiency and minimizing any interference to the primary licensed users.

  15. Large-scale HI in nearby radio galaxies : segregation in neutral gas content with radio source size

    NARCIS (Netherlands)

    Emonts, B. H. C.; Morganti, R.; Oosterloo, T. A.; van der Hulst, J. M.; van Moorsel, G.; Tadhunter, C. N.

    2007-01-01

    We present results of a study of neutral hydrogen ( HI) in a complete sample of nearby non-cluster radio galaxies. We find that radio galaxies with large amounts of extended HI (M-HI >= 109 M-circle dot) all have a compact radio source. The host galaxies of the more extended radio sources, all of Fa

  16. Brightest cluster galaxies in the extended GMRT radio halo cluster sample. Radio properties and cluster dynamics

    Science.gov (United States)

    Kale, R.; Venturi, T.; Cassano, R.; Giacintucci, S.; Bardelli, S.; Dallacasa, D.; Zucca, E.

    2015-09-01

    Aims: First-ranked galaxies in clusters, usually referred to as brightest cluster galaxies (BCGs), show exceptional properties over the whole electromagnetic spectrum. They are the most massive elliptical galaxies and show the highest probability to be radio loud. Moreover, their special location at the centres of galaxy clusters raises the question of the role of the environment in shaping their radio properties. In the attempt to separate the effect of the galaxy mass and of the environment on their statistical radio properties, we investigate the possible dependence of the occurrence of radio loudness and of the fractional radio luminosity function on the dynamical state of the hosting cluster. Methods: We studied the radio properties of the BCGs in the Extended GMRT Radio Halo Survey (EGRHS), which consists of 65 clusters in the redshift range 0.2-0.4, with X-ray luminosity LX ≥ 5 × 1044 erg s-1, and quantitative information on their dynamical state from high-quality Chandra imaging. We obtained a statistical sample of 59 BCGs, which we divided into two classes, depending on whether the dynamical state of the host cluster was merging (M) or relaxed (R). Results: Of the 59 BCGs, 28 are radio loud and 31 are radio quiet. The radio-loud sources are favourably located in relaxed clusters (71%), while the reverse is true for the radio-quiet BCGs, which are mostly located in merging systems (81%). The fractional radio luminosity function for the BCGs in merging and relaxed clusters is different, and it is considerably higher for BCGs in relaxed clusters, where the total fraction of radio loudness reaches almost 90%, to be compared to the ~30% in merging clusters. For relaxed clusters, we found a positive correlation between the radio power of the BCGs and the strength of the cool core, consistent with previous studies on local samples. Conclusions: Our study suggests that the radio loudness of the BCGs strongly depends on the cluster dynamics; their fraction is

  17. The radio luminosity function and redshift evolution of radio-mode and quasar-mode AGN

    Science.gov (United States)

    Pracy, Mike

    2016-08-01

    The properties of the AGN population indicate that there are two fundamentally different accretion modes operating. In the quasar-mode, material is accreted onto the supermassive black hole via a small, thin, optically luminous accretion disc. Accretion in this mode is recognisable by emission lines in the optical spectrum. However, there is a population of AGN observable only by their radio emission and without optical emission lines. These radio-mode AGN are likely powered by radiatively inefficient accretion from a hot gas halo. I will describe the cosmic evolution of these two populations via radio luminosity functions. The radio luminosity functions are constructed from a new survey of over 4000 radio galaxies out to z=1, all with confirmed redshifts and their accretion mode classified from their optical spectra. This is 20 times larger than the only other survey used to make such a measurement. The radio-mode AGN population displays no statistically significant evolution in space density out to redshift z=1. In contrast the quasar mode AGN exhibits rapid evolution in space density, increasing by a factor of 8 over the same redshift range. The characteristic break in the radio luminosity function occurs at a significantly higher power for the quasar-mode AGN in comparison to the radio-mode AGN and we demonstrate this is consistent with the two populations representing fundamentally different accretion modes. The radio luminosity function is used to estimate the total amount of mechanical energy available for radio mode feedback as a function of redshift, and is found to be in good agreement with cosmological models and previous measurements. Again, by separating by accretion mode, the previously estimated increase in available mechanical energy per unit volume out to z=1 (approximately a factor of 2) can be attributed to the rapid evolution of the quasar-mode AGN, while for the classical radio-mode AGN the total mechanical energy output remains roughly

  18. Tough New Issues Refocus Health Education

    Science.gov (United States)

    Dessoff, Alan

    2011-01-01

    From dating violence to sexting and social networking, districts are struggling to address a number of sensitive and relatively new health education issues that are aggravated by students' increasing access to computers, cell phones and other digital devices. Through new or revised curricula, administrators are attempting to deal with these and…

  19. REFOCUSING MARKETING TO REFLECT SOCIAL RESPONSABILITY

    OpenAIRE

    TRISCA Gelu; CIORTUZ Adela

    2012-01-01

    As traditional marketing statements are inherently in conflict with the social responsibilities of companies to customers, the concept of corporate social responsibility is a dead end. In this paper, based on assumptions of the Service Dominant logic and Service science, we conceptualize a marketing framework in which social priorities are consistently integrated into the company's operational considerations. The implications are manifold. Academic researchers can adopt a new research perspec...

  20. Refocusing research priorities in schools of nursing.

    Science.gov (United States)

    Kulage, Kristine M; Ardizzone, Laura; Enlow, William; Hickey, Kathleen; Jeon, Christie; Kearney, Joan; Schnall, Rebecca; Larson, Elaine L

    2013-01-01

    It is critical for schools of nursing to periodically reassess their scholarly programs to ensure that their conceptual framework and approaches address current challenges and enhance productivity. This article describes the process undertaken at Columbia University School of Nursing to evaluate scholarly enterprise so that it remains relevant and responsive to changing trends and to revise our research conceptual model to be reflective of the foci of our clinicians and researchers. As part of a larger strategic initiative, a two-phase Research Excellence Planning and Implementation Workgroup was convened, consisting of a broad representation of faculty and administrative staff, with an overall goal of expanding scholarly capacity. During Phase I, members developed measurable outcomes and tactics and revised the school's conceptual research model. In Phase II, the workgroup implemented and monitored tactics and presented final recommendations to the dean. To measure progress, faculty members completed a survey to establish baseline scholarship and collaboration with results indicating room for growth in interdisciplinary and inter-institutional collaboration. Ongoing assessment of outcomes includes Web-based tracking of scholarly activities and follow-up surveys to monitor expansion of faculty collaboration. We recommend this process to other schools committed to sustainable, increasingly relevant scholarship.

  1. Radio and the educational needs of Africa.

    Science.gov (United States)

    Quarmyne, A T

    1985-01-01

    Democratization of education is the first priority need as defined by African Ministers of Education and economic planners and voiced at a conference held in Zimbabwe in 1982. This democratization depends principally on the spread and maintenance of the education delivery system. The traditional mechanisms of education, mainly schools, are structurally incapable of carrying out the task of democratization. Education of the scale and type required by Africa cannot be realized through and in the classroom alone. Radio, 1 of Africa's great wasted resources, was enthusiastically hailed by African governments at independence as a powerful instrument for education both in its broadest and more limited sense. It was the perfect medium for an impoverished, disadvantaged continent. National development plans have consistently provided for improvement of the broadcasting transmission infrastructure. Most African countries currently are able to distribute radio programs to over 90% of their populations and at least 7 countries have 100% radio coverage. A total solution to the once most difficult problem of reception facilities is now within reach. From the results of many educational radio projects around the world and other studies, it is now generally accepted that, particularly in situations where educational radio does not imply the creation of separate networks of production and transmission facilities, much higher cost effectiveness over traditional classroom teaching can be graranteed. It is also clearly established that the cost effectiveness of radio in education can be as high as 5 times that of television. Reviewing a list of some 23 projects which have been labeled as educational radio projects in Africa over the past 2 decades, only 5 can be identified as having successfully fulfilled their objectives or as being in process of doing so. This is not an impressive score. Experience with the 5 truly successul projects indicates that it is not only a particular type

  2. Sensitive radio survey of obscured quasar candidates

    Science.gov (United States)

    Alexandroff, Rachael M.; Zakamska, Nadia L.; van Velzen, Sjoert; Greene, Jenny E.; Strauss, Michael A.

    2016-12-01

    We study the radio properties of moderately obscured quasars in samples at both low (z ˜ 0.5) and high (z ˜ 2.5) redshift to understand the role of radio activity in accretion, using the Karl G. Jansky Very Large Array (VLA) at 6.0 GHz and 1.4 GHz. Our z ˜ 2.5 sample consists of optically selected obscured quasar candidates, all of which are radio-quiet, with typical radio luminosities of νLν[1.4 GHz] ≲ 1040 erg s-1. Only a single source is individually detected in our deep (rms˜10 μJy) exposures. This population would not be identified by radio-based selection methods used for distinguishing dusty star-forming galaxies and obscured active nuclei. In our pilot A-array study of z ˜ 0.5 radio-quiet quasars, we spatially resolve four of five objects on scales ˜5 kpc and find they have steep spectral indices with an average value of α = -0.75. Therefore, radio emission in these sources could be due to jet-driven or radiatively driven bubbles interacting with interstellar material on the scale of the host galaxy. Finally, we also study the additional population of ˜200 faint ( ˜ 40 μJy-40 mJy) field radio sources observed over ˜120 arcmin2 of our data. 60 per cent of these detections (excluding our original targets) are matched in the Sloan Digital Sky Survey (SDSS) and/or Wide-Field Infrared Survey Explorer (WISE) and are, in roughly equal shares, active galactic nuclei (AGN) at a broad range of redshifts, passive galaxies with no other signs of nuclear activity and infrared-bright but optically faint sources. Spectroscopically or photometrically confirmed star-forming galaxies constitute only a small minority of the matches. Such sensitive radio surveys allow us to address important questions of AGN evolution and evaluate the AGN contribution to the radio-quiet sky.

  3. Size dependence of the radio-luminosity-mechanical-power correlation in radio galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Shabala, S. S. [School of Mathematics and Physics, Private Bag 37, University of Tasmania, Hobart, TAS 7001 (Australia); Godfrey, L. E. H., E-mail: Stanislav.Shabala@utas.edu.au [International Centre for Radio Astronomy Research, Curtin University, GPO Box U1987, Perth, Western Australia 6845 (Australia)

    2013-06-01

    We examine the relationship between source radio luminosity and kinetic power in active galactic nucleus jets. We show that neglecting various loss processes can introduce a systematic bias in the jet powers inferred from radio luminosities for a sample of radio galaxies. This bias can be corrected for by considering source size as well as radio luminosity; effectively the source size acts as a proxy for source age. Based on a sample of Fanaroff-Riley Type II radio sources with jet powers derived from the measured hotspot parameters, we empirically determine a new expression for jet power that accounts for the source size, (Q{sub jet}/10{sup 36} W)=1.5{sub −0.8}{sup +1.8}(L{sub 151}/10{sup 27} W Hz{sup −1}){sup 0.8}(1+z){sup 1.0}(D/kpc){sup 0.58±0.17}, where D is source size and L {sub 151} the 151 MHz radio luminosity. By comparing a flux-limited and volume-limited sample, we show that any derived radio-luminosity-jet-power relation depends sensitively on sample properties, in particular the source size distribution and the size-luminosity correlation inherent in the sample. Such bias will affect the accuracy of the kinetic luminosity function derived from lobe radio luminosities and should be treated with caution.

  4. Planck early results. XV. Spectral energy distributions and radio continuum spectra of northern extragalactic radio sources

    DEFF Research Database (Denmark)

    Aatrokoski, J.; Lavonen, N.; León-Tavares, J.

    2011-01-01

    Spectral energy distributions (SEDs) and radio continuum spectra are presented for a northern sample of 104 extragalactic radio sources, based on the Planck Early Release Compact Source Catalogue (ERCSC) and simultaneous multifrequency data. The nine Planck frequencies, from 30 to 857 GHz, are co...

  5. Planck early results. XV. Spectral energy distributions and radio continuum spectra of northern extragalactic radio sources

    DEFF Research Database (Denmark)

    Aatrokoski, J.; Lavonen, N.; León-Tavares, J.;

    2011-01-01

    Spectral energy distributions (SEDs) and radio continuum spectra are presented for a northern sample of 104 extragalactic radio sources, based on the Planck Early Release Compact Source Catalogue (ERCSC) and simultaneous multifrequency data. The nine Planck frequencies, from 30 to 857 GHz, are co...

  6. Radio Identifications of Markarian Galaxies and the Correlation between Radio and Far-Infrared Properties

    Institute of Scientific and Technical Information of China (English)

    Shao-Guang Luo; Xue-Bing Wu

    2005-01-01

    By checking DSS optical images and NVSS radio images, 782 Markarian galaxies were identified to be NVSS radio sources. A comparison of the radio luminosity at 1.4 GHz and the far-infrared (FIR) luminosity for 468 "normal"galaxies shows a tight correlation. Most of the Seyfert galaxies and quasars follow the radio-FIR relation deduced from the "normal" galaxy sample, but with a somewhat larger scatter. A total 167 Markarian galaxies, comprising 100 "normal"galaxies, 66 Seyfert galaxies and one quasar, have either excess radio emission or much lower FIR spectral index α(25μm, 60μm). These galaxies may be classified as "AGN-powered". For "normal" galaxies, the average q value (defined as the log ratio between FIR and radio luminosities) is 2.3. There seems a trend for q to slightly decrease with increasing radio luminosity. This may imply that the ongoing active star formation in galaxies with higher radio luminosities is more efficient in heating the cosmic-ray electrons.

  7. Accurate radio and optical positions for the radio star HD 36705 (AB Doradus)

    Science.gov (United States)

    White, Graeme L.; Jauncey, David L.; Batty, Michael J.; Peters, W. L.; Gulkis, S.

    1988-01-01

    Arc-second position measurements of the active star HD 36705 (AB Dor) and of the variable radio source found nearby are presented. These measurements show that the radio source is clearly identified with HD 36705 and not with the nearby red-dwarf star Rst 137B.

  8. Radio Galaxy Zoo: host galaxies and radio morphologies derived from visual inspection

    CERN Document Server

    Banfield, J K; Willett, K W; Norris, R P; Rudnick, L; Shabala, S S; Simmons, B D; Snyder, C; Garon, A; Seymour, N; Middelberg, E; Andernach, H; Lintott, C J; Jacob, K; Kapinska, A D; Mao, M Y; Masters, K L; Jarvis, M J; Schawinski, K; Paget, E; Simpson, R; Klockner, H R; Bamford, S; Burchell, T; Chow, K E; Cotter, G; Fortson, L; Heywood, I; Jones, T W; Kaviraj, S; Lopez-Sanchez, A R; Maksym, W P; Polsterer, K; Borden, K; Hollow, R P; Whyte, L

    2015-01-01

    We present results from the first twelve months of operation of Radio Galaxy Zoo, which upon completion will enable visual inspection of over 170,000 radio sources to determine the host galaxy of the radio emission and the radio morphology. Radio Galaxy Zoo uses $1.4\\,$GHz radio images from both the Faint Images of the Radio Sky at Twenty Centimeters (FIRST) and the Australia Telescope Large Area Survey (ATLAS) in combination with mid-infrared images at $3.4\\,\\mu$m from the {\\it Wide-field Infrared Survey Explorer} (WISE) and at $3.6\\,\\mu$m from the {\\it Spitzer Space Telescope}. We present the early analysis of the WISE mid-infrared colours of the host galaxies. For images in which there is $>\\,75\\%$ consensus among the Radio Galaxy Zoo cross-identifications, the project participants are as effective as the science experts at identifying the host galaxies. The majority of the identified host galaxies reside in the mid-infrared colour space dominated by elliptical galaxies, quasi-stellar objects (QSOs), and l...

  9. Solar system radio emissions studies with the largest low-frequency radio telescopes

    Science.gov (United States)

    Zakharenko, V.; Konovalenko, A.; Litvinenko, G.; Kolyadin, V.; Zarka, P.; Mylostna, K.; Vasylieva, I.; Griessmeier, J.-M.; Sidorchuk, M.; Rucker, H.; Fischer, G.; Cecconi, B.; Coffre, A.; Denis, L.; Shevchenko, V.; Nikolaenko, V.

    2014-04-01

    We describe the trends and tasks in the field of lowfrequency studies of radio emission from the Solar system's objects. The world's largest decameter radio telescopes UTR-2 and URAN have a unique combination of sensitivity and time/frequency resolution parameters, providing the capability of the most detailed studies of various types of solar and planetary emissions.

  10. Transistor Radio Receivers; Radio and Television Service, Intermediate: 9785.04.

    Science.gov (United States)

    Dade County Public Schools, Miami, FL.

    The course outlined is one of the required courses in the Radio and Television Service Curriculum. Mastery of the skills in Basic Radio Circuits and Vacuum Tube AM Troubleshooting (9785.03) is a prerequisite. Eight blocks of instruction are divided into several units each. The instruction blocks are: orientation, fundamentals of transistor…

  11. The radio spectral energy distribution of infrared-faint radio sources

    CERN Document Server

    Herzog, A; Middelberg, E; Seymour, N; Spitler, L R; Emonts, B H C; Franzen, T M O; Hunstead, R; Intema, H T; Marvil, J; Parker, Q A; Sirothia, S K; Hurley-Walker, N; Bell, M; Bernardi, G; Bowman, J D; Briggs, F; Cappallo, R J; Callingham, J R; Deshpande, A A; Dwarakanath, K S; For, B -Q; Greenhill, L J; Hancock, P; Hazelton, B J; Hindson, L; Johnston-Hollitt, M; Kapinska, A D; Kaplan, D L; Lenc, E; Lonsdale, C J; McKinley, B; McWhirter, S R; Mitchell, D A; Morales, M F; Morgan, E; Morgan, J; Oberoi, D; Offringa, A; Ord, S M; Prabu, T; Procopio, P; Shankar, N Udaya; Srivani, K S; Staveley-Smith, L; Subrahmanyan, R; Tingay, S J; Wayth, R B; Webster, R L; Williams, A; Williams, C L; Wu, C; Zheng, Q; Chippendale, A P; Harvey-Smith, L; Heywood, I; Indermuehle, B; Popping, A; Sault, R J; Whiting, M T

    2016-01-01

    Infrared-faint radio sources (IFRS) are a class of radio-loud (RL) active galactic nuclei (AGN) at high redshifts (z > 1.7) that are characterised by their relative infrared faintness, resulting in enormous radio-to-infrared flux density ratios of up to several thousand. We aim to test the hypothesis that IFRS are young AGN, particularly GHz peaked-spectrum (GPS) and compact steep-spectrum (CSS) sources that have a low frequency turnover. We use the rich radio data set available for the Australia Telescope Large Area Survey fields, covering the frequency range between 150 MHz and 34 GHz with up to 19 wavebands from different telescopes, and build radio spectral energy distributions (SEDs) for 34 IFRS. We then study the radio properties of this class of object with respect to turnover, spectral index, and behaviour towards higher frequencies. We also present the highest-frequency radio observations of an IFRS, observed with the Plateau de Bure Interferometer at 105 GHz, and model the multi-wavelength and radio...

  12. Curved Radio Spectra of Weak Cluster Shocks

    Science.gov (United States)

    Kang, Hyesung; Ryu, Dongsu

    2015-08-01

    In order to understand certain observed features of arc-like giant radio relics such as the rareness, uniform surface brightness, and curved integrated spectra, we explore a diffusive shock acceleration (DSA) model for radio relics in which a spherical shock impinges on a magnetized cloud containing fossil relativistic electrons. Toward this end, we perform DSA simulations of spherical shocks with the parameters relevant for the Sausage radio relic in cluster CIZA J2242.8+5301, and calculate the ensuing radio synchrotron emission from re-accelerated electrons. Three types of fossil electron populations are considered: a delta-function like population with the shock injection momentum, a power-law distribution, and a power law with an exponential cutoff. The surface brightness profile of the radio-emitting postshock region and the volume-integrated radio spectrum are calculated and compared with observations. We find that the observed width of the Sausage relic can be explained reasonably well by shocks with speed {u}{{s}}˜ 3× {10}3 {km} {{{s}}}-1 and sonic Mach number {M}{{s}}˜ 3. These shocks produce curved radio spectra that steepen gradually over (0.1-10){ν }{br} with a break frequency {ν }{br}˜ 1 GHz if the duration of electron acceleration is ˜60-80 Myr. However, the abrupt increase in the spectral index above ˜1.5 GHz observed in the Sausage relic seems to indicate that additional physical processes, other than radiative losses, operate for electrons with {γ }{{e}}≳ {10}4.

  13. The death of FRII radio sources and their connection with radio relics

    CERN Document Server

    Kaiser, C R; Kaiser, Christian R.; Cotter, Garret

    2002-01-01

    Radio relic sources in galaxy clusters are often described as the remnants of powerful radio galaxies. Here we develop a model for the evolution of such relics after the jets cease to supply energy to the lobes. This includes the treatment of a relic overpressured with respect to its gaseous surroundings even after the jets switch off. We also determine the radio emission of relics for a large variety of assumptions. We take into account the evolution of the strength of the magnetic field during the phase of relativistic particle injection into the lobes. The resulting spectra show mild steepening at around 1 GHz but avoid any exponential spectral cut-offs. The model calculations are used to fit the observed spectra of six radio relics. The quality of the fits is excellent for {\\it all} models discussed. Unfortunately, this implies that it is virtually impossible to determine any of the important source parameters from the observed radio emission alone.

  14. New radio model in the fourth screen: radiovision, the radio that you can watch

    Directory of Open Access Journals (Sweden)

    Sandra CAVIA FRAILE

    2016-12-01

    Full Text Available The traditional radio is not strange to the social revolution that Internet and new technologies are raising. In recent years, the fourth screen has led the emergence of new models of radio, including Radiovision. The «radio that you can watch» intends to change and innovate the radio broadcasting media to offer a product that meets the multimedia requirements of users. However, currently, the Radiovisión is still at an early stage and it has many aspects that it should improve and care, as the contents and the staging. It is a big chance for the radio that poses challenges and opportunities both for journalism and journalists.

  15. Mutual distance dependence drives the observed jet-power-radio-luminosity scaling relations in radio galaxies

    Science.gov (United States)

    Godfrey, L. E. H.; Shabala, S. S.

    2016-02-01

    The kinetic power of radio jets is a quantity of fundamental importance to studies of the AGN feedback process and radio galaxy physics. A widely used proxy for jet power is the extended radio luminosity. A number of empirical methods have been used to calibrate a scaling relationship between jet power (Q) and radio luminosity (L) of the form log (Q) = βL log (L) + C. The regression slope has typically been found to be βL ˜ 0.7-0.8. Here we show that the previously reported scaling relations are strongly affected by the confounding variable, distance. We find that in a sample of FRI X-ray cavity systems, after accounting for the mutual distance dependence, the jet power and radio luminosity are only weakly correlated, with slope βL ≈ 0.3: significantly flatter than previously reported. We also find that in previously used samples of high-power sources, no evidence for an intrinsic correlation is present when the effect of distance is accounted for. Using a simple model we show that βL is expected to be significantly lower in samples of FRI radio galaxies than it is for FRIIs, due to the differing dynamics for these two classes of radio source. For FRI X-ray cavity systems the model predicts βL(FRI) ≳ 0.5 in contrast to FRII radio galaxies, for which βL(FRII) ≳ 0.8. We discuss the implications of our finding for studies of radio mode feedback, and radio galaxy physics.

  16. 3C 57 as an atypical radio-loud quasar: implications for the radio-loud/radio-quiet dichotomy

    Science.gov (United States)

    Sulentic, J. W.; Martínez-Carballo, M. A.; Marziani, P.; del Olmo, A.; Stirpe, G. M.; Zamfir, S.; Plauchu-Frayn, I.

    2015-06-01

    Lobe-dominated radio-loud (LD RL) quasars occupy a restricted domain in the 4D Eigenvector 1 (4DE1) parameter space which implies restricted geometry/physics/kinematics for this subclass compared to the radio-quiet (RQ) majority of quasars. We discuss how this restricted domain for the LD RL parent population supports the notion for a RQ-RL dichotomy among type 1 sources. 3C 57 is an atypical RL quasar that shows both uncertain radio morphology and falls in a region of 4DE1 space where RL quasars are rare. We present new radio flux and optical spectroscopic measures designed to verify its atypical optical/UV spectroscopic behaviour and clarify its radio structure. The former data confirms that 3C 57 falls off the 4DE1 quasar `main sequence' with both extreme optical Fe II emission (R_{Fe II} ˜ 1) and a large C IV λ1549 profile blueshift (˜-1500 km s-1). These parameter values are typical of extreme Population A sources which are almost always RQ. New radio measures show no evidence for flux change over a 50+ year time-scale consistent with compact steep-spectrum (or young LD) over core-dominated morphology. In the 4DE1 context where LD RL are usually low L/LEdd quasars, we suggest that 3C 57 is an evolved RL quasar (i.e. large blackhole mass) undergoing a major accretion event leading to a rejuvenation reflected by strong Fe II emission, perhaps indicating significant heavy metal enrichment, high bolometric luminosity for a low-redshift source and resultant unusually high Eddington ratio giving rise to the atypical C IV λ1549.

  17. Radio occultation measurements of the lunar ionosphere.

    Science.gov (United States)

    Pluchino, S.; Schillirò, F.; Salerno, E.; Pupillo, G.; Maccaferri, G.; Cassaro, P.

    Radio occultation measurements by using interplanetary probes is a well known technique to obtain information on planetary atmospheres. To further understand the morphology of the lunar ionosphere we performed radio occultation experiments by using the radio sounding technique. This method mainly consists in the analisys of the effects produced on the radio wave transmitted from the spacecraft to the Earth when it crosses the atmosphere. The wave amplitude and phase undergo modifications that are correlated to the physical parameters - i.e. electron density - of the crossed medium. The first data set was obtained during the lunar occultations of the European probe SMART-1 shortly before impacting the lunar soil on September 3rd, 2006. During this experiment several radio occultation measurements of the signal transmitted by the spacecraft were performed in S and X band by using the 32 meters radiotelescopes (at Medicina and Noto) of the Istituto di Radioastronomia - Istituto Nazionale di Astrofisica. Further experiments were performed during lunar occultations of Saturn and Venus. On May 22nd and June 18th 2007 the Cassini spacecraft, orbiting Saturn, and the Venus Express spacecraft, orbiting Venus, respectively were occulted by the Moon. The variation of the Total Electron Content (TEC) measured by our instruments (˜ 1013 el/m2) on this occasion is in agreement with values of the electron number density acquired by in situ measuments of the US Apollo missions and the USSR Luna 19 and 22 probes.

  18. Latest results of the Tunka Radio Extension

    Directory of Open Access Journals (Sweden)

    Kostunin D.

    2017-01-01

    Full Text Available The Tunka Radio Extension (Tunka-Rex is an antenna array consisting of 63 antennas at the location of the TAIGA facility (Tunka Advanced Instrument for cosmic ray physics and Gamma Astronomy in Eastern Siberia, nearby Lake Baikal. Tunka-Rex is triggered by the air-Cherenkov array Tunka-133 during clear and moonless winter nights and by the scintillator array Tunka-Grande during the remaining time. Tunka-Rex measures the radio emission from the same air-showers as Tunka-133 and Tunka-Grande, but with a higher threshold of about 100 PeV. During the first stages of its operation, Tunka-Rex has proven, that sparse radio arrays can measure air-showers with an energy resolution of better than 15% and the depth of the shower maximum with a resolution of better than 40 g/cm2. To improve and interpret our measurements as well as to study systematic uncertainties due to interaction models, we perform radio simulations with CORSIKA and CoREAS. In this overview we present the setup of Tunka-Rex, discuss the achieved results and the prospects of mass-composition studies with radio arrays.

  19. Developing Benchmarks for Solar Radio Bursts

    Science.gov (United States)

    Biesecker, D. A.; White, S. M.; Gopalswamy, N.; Black, C.; Domm, P.; Love, J. J.; Pierson, J.

    2016-12-01

    Solar radio bursts can interfere with radar, communication, and tracking signals. In severe cases, radio bursts can inhibit the successful use of radio communications and disrupt a wide range of systems that are reliant on Position, Navigation, and Timing services on timescales ranging from minutes to hours across wide areas on the dayside of Earth. The White House's Space Weather Action Plan has asked for solar radio burst intensity benchmarks for an event occurrence frequency of 1 in 100 years and also a theoretical maximum intensity benchmark. The solar radio benchmark team was also asked to define the wavelength/frequency bands of interest. The benchmark team developed preliminary (phase 1) benchmarks for the VHF (30-300 MHz), UHF (300-3000 MHz), GPS (1176-1602 MHz), F10.7 (2800 MHz), and Microwave (4000-20000) bands. The preliminary benchmarks were derived based on previously published work. Limitations in the published work will be addressed in phase 2 of the benchmark process. In addition, deriving theoretical maxima requires additional work, where it is even possible to, in order to meet the Action Plan objectives. In this presentation, we will present the phase 1 benchmarks and the basis used to derive them. We will also present the work that needs to be done in order to complete the final, or phase 2 benchmarks.

  20. Faint Radio Sources and Star Formation History

    CERN Document Server

    Haarsma, D B; Windhorst, R A; Richards, E A; 10.1086/317225

    2010-01-01

    The centimeter-wave luminosity of local radio galaxies correlates well with their star formation rate. We extend this correlation to surveys of high-redshift radio sources to estimate the global star formation history. The star formation rate found from radio observations needs no correction for dust obscuration, unlike the values calculated from optical and ultraviolet data. Three deep radio surveys have provided catalogs of sources with nearly complete optical identifications and nearly 60% complete spectroscopic redshifts: the Hubble Deep Field and Flanking Fields at 12h+62d, the SSA13 field at 13h+42d, and the V15 field at 14h+52d. We use the redshift distribution of these radio sources to constrain the evolution of their luminosity function. The epoch dependent luminosity function is then used to estimate the evolving global star formation density. At redshifts less than one, our calculated star formation rates are significantly larger than even the dust-corrected optically-selected star formation rates;...