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Sample records for existed radio immunochemical

  1. Immunochemical studies of infectious mononucleosis

    International Nuclear Information System (INIS)

    Fletcher, M.A.; Lo, T.M.; Levey, B.A.; Graves, W.R.

    1977-01-01

    The coated-tube method of solid-phase radioimmunoassay has been adapted to the detection of heterophile antibodies and antigens of infectious mononucleosis. Disposable plastic hemagglutination trays were coated with purified glycoprotein from horse erythrocytes and the subsequent uptake of antibody from test sera was detected by radio-iodinated horse erythrocyte glycoprotein. In a preliminary survey of sera from patients with infectious mononucleosis and sera from controls, the assay proved highly sensitive and specific. The test system was also useful in a competitive binding assay for immunochemical studies of glycoproteins from other heterophile antigen-positive species

  2. Immunochemical protocols

    National Research Council Canada - National Science Library

    Pound, John D

    1998-01-01

    ... easy and important refinements often are not published. This much anticipated 2nd edition of Immunochemzcal Protocols therefore aims to provide a user-friendly up-to-date handbook of reliable techniques selected to suit the needs of molecular biologists. It covers the full breadth of the relevant established immunochemical methods, from protein blotting and immunoa...

  3. Immunochemical studies of yellowjacket venom proteins.

    Science.gov (United States)

    King, T P; Alagon, A C; Kuan, J; Sobotka, A K; Lichtenstein, L M

    1983-03-01

    The major proteins of yellowjacket venoms have been isolated and characterized immuno-chemically. They consist of hyaluronidase, phospholipase, and antigen 5. Venoms from three species of yellowjacket were studied. Vespula germanica, V. maculifrons, and V. vulgaris. The phospholipases could be isolated in good yield only when affinity chromatography was used to minimize limited proteolysis. A kallikrein-like peptidase was found present in the yellowjacket venom. Phospholipases from these three species were immunochemically indistinguishable from each other, as were their antigen 5s. Sera from individuals sensitive to yellowjacket venom contained IgE and IgG specific for antigen 5 and phospholipase.

  4. Method for determining immunochemical substances

    International Nuclear Information System (INIS)

    O'connor, J.

    1980-01-01

    Drawing a method for detecting and measuring a predetermined specifically-bindable immunochemical substance in a liquid sample in a cuvette, comprising the steps of: (A) providing, in an immunoassay technique for the liquid sample in said cuvette, a component comprising a suspension of particles which may be agglutinated or insolubilized in relationship to the presence and concentration of the immunochemical substance in the sample; and (B) determining the presence and concentration of the immunochemical substance by measuring the electromagnetic radiation transmission properties of the sample using a calibrated radiation-measuring apparatus, said apparatus comprising: (1) a suitable electromagnetic radiation source capable of providing radiation at wavelengths equal to or less than the mean diameter of said particles; (2) means for concentrating and collimating radiation from the electromagnetic radiation source to form a beam; (3) means for filtering the beam to (I) eliminate radiation having wavelengths greater than the means diameter of the particles and (II) transmit radiation, which radiation has a range, whereby the upper wavelength is equal to or below the mean diameter of the particles, and the range is of at least about 100nm; (4) means for (I) positioning a sample-containing cuvette and for (II) allowing the filtered beam incident on the cuvette to be transmitted through the cuvette and sample, and for (III) receiving a portion of the filtered beam transmitted through the sample at two or more predetermined angles with respect to the beam; and (5) means for detecting and measuring the portion of the beam transmitted at a predetermined angle

  5. Coated tube for immunochemical and enzymatic assays

    International Nuclear Information System (INIS)

    Brown, J.L.; Lin, W.H.-T.; Woods, J.W.

    1979-01-01

    Containers such as test tubes suitable for use in solid phase immunochemical, enzymatical and particularly radioimmunoassay procedures are described. The lower part of the tube is a polymer, coated with an inert protein to which a biologically active substance eg an antibody to triiodothyronine, thyroxine or digoxin, is attached. (U.K.)

  6. Incidence of interval cancers in faecal immunochemical test colorectal screening programmes in Italy.

    Science.gov (United States)

    Giorgi Rossi, Paolo; Carretta, Elisa; Mangone, Lucia; Baracco, Susanna; Serraino, Diego; Zorzi, Manuel

    2018-03-01

    Objective In Italy, colorectal screening programmes using the faecal immunochemical test from ages 50 to 69 every two years have been in place since 2005. We aimed to measure the incidence of interval cancers in the two years after a negative faecal immunochemical test, and compare this with the pre-screening incidence of colorectal cancer. Methods Using data on colorectal cancers diagnosed in Italy from 2000 to 2008 collected by cancer registries in areas with active screening programmes, we identified cases that occurred within 24 months of negative screening tests. We used the number of tests with a negative result as a denominator, grouped by age and sex. Proportional incidence was calculated for the first and second year after screening. Results Among 579,176 and 226,738 persons with negative test results followed up at 12 and 24 months, respectively, we identified 100 interval cancers in the first year and 70 in the second year. The proportional incidence was 13% (95% confidence interval 10-15) and 23% (95% confidence interval 18-25), respectively. The estimate for the two-year incidence is 18%, which was slightly higher in females (22%; 95% confidence interval 17-26), and for proximal colon (22%; 95% confidence interval 16-28). Conclusion The incidence of interval cancers in the two years after a negative faecal immunochemical test in routine population-based colorectal cancer screening was less than one-fifth of the expected incidence. This is direct evidence that the faecal immunochemical test-based screening programme protocol has high sensitivity for cancers that will become symptomatic.

  7. Immunochemical and immunocytochemical studies of the crustacean vitellogenesis-inhibiting hormone (VIH).

    Science.gov (United States)

    Meusy, J J; Martin, G; Soyez, D; van Deijnen, J E; Gallo, J M

    1987-09-01

    Immunochemical investigations, using dot immunobinding assay (DIA) and enzyme-linked immunosorbent assay (ELISA), and immunocytochemical studies reveal the following new information about crustacean vitellogenesis-inhibiting hormone (VIH): (1) The structure of VIH is sufficiently different from that of the other sinus gland neuropeptides to allow a selective recognition of VIH by polyclonal antibodies. (2) From immunochemical criteria, VIH does not seem strictly species specific. The antisera raised against VIH of Homarus americanus cross-react with sinus gland extracts of Palaemonetes varians, Palaemon serratus, Macrobrachium rosenbergii, Carcinus maenas, and Porcellio dilatatus. (3) In the sinus gland of H. americanus, VIH immunoreactivity is localized mainly in electron-dense granules of medium size (110-185 nm in diameter) while, in P. dilatatus, the labeling is mostly on the largest granules (200-270 nm in diameter).

  8. Implementation of immunochemical faecal occult blood test in general practice

    DEFF Research Database (Denmark)

    Juul, Jakob Søgaard; Bro, Flemming; Hornung, Nete

    2016-01-01

    anvendelsen af immunochemical faecal occult blood test (iFOBT) i almen praksis. iFOBT detekterer humant globin i fæces og indikerer gastrointestinal blødning. Studiet udgør en del af et ph.d.-studie, der bidrager med ny viden til at optimere udredningen af patienter med tarmkræft. Der er et stort behov...

  9. Earlier stages of colorectal cancer detected with immunochemical faecal occult blood tests

    NARCIS (Netherlands)

    van Rossum, L. G. M.; van Rijn, A. F.; van Munster, I. P.; Jansen, J. B. M. J.; Fockens, P.; Laheij, R. J. F.; Dekker, E.

    2009-01-01

    Background: The aim of colorectal cancer screening is to improve prognosis by the detection of early cancer and precursor stages. We compared the stage distribution of asymptomatic colorectal cancer patients detected by a positive immunochemical or guaiac-based faecal occult blood test (FOBT) with

  10. An immunochemical approach to the study of DNA damage and repair

    International Nuclear Information System (INIS)

    Wallace, S.S.

    1991-08-01

    The overall objective of this project is to produce antibodies to unique modified DNA bases and develop immunochemical assays to quantitate these lesions in damaged DNA. During this past year we have characterized antibodies to 8-oxopurines, produced novel antibodies to 5-hydroxyuracil and developed new methodologies to increase our level of sensitivity of detection. 7 refs., 5 figs

  11. Hemorrhoids detected at colonoscopy: an infrequent cause of false-positive fecal immunochemical test results.

    NARCIS (Netherlands)

    Turenhout, S.T. van; Oort, F.A.; Terhaar sive Droste, J.S.; Coupe, V.M.; Hulst, R.W. van der; Loffeld, R.J.; Scholten, P.; Depla, A.C.; Bouman, A.A.; Meijer, G.A.; Mulder, C.J.; Rossum, L.G.M. van

    2012-01-01

    BACKGROUND: Colorectal cancer screening by fecal immunochemical tests (FITs) is hampered by frequent false-positive (FP) results and thereby the risk of complications and strain on colonoscopy capacity. Hemorrhoids might be a plausible cause of FP results. OBJECTIVE: To determine the contribution of

  12. Cost-effectiveness of one versus two sample faecal immunochemical testing for colorectal cancer screening

    NARCIS (Netherlands)

    S.L. Goede (Luuk); A.H.C. Roon (Aafke); J.C.I.Y. Reijerink (Jacqueline); A.J. van Vuuren (Hanneke); I. Lansdorp-Vogelaar (Iris); J.D.F. Habbema (Dik); E.J. Kuipers (Ernst); M.E. van Leerdam (Monique); M. van Ballegooijen (Marjolein)

    2013-01-01

    textabstractObjective The sensitivity and specificity of a single faecal immunochemical test (FIT) are limited. The performance of FIT screening can be improved by increasing the screening frequency or by providing more than one sample in each screening round. This study aimed to evaluate if

  13. An immunochemical approach to the study of DNA damage and repair: Technical progress report, August 1, 1986 to July 31, 1987

    International Nuclear Information System (INIS)

    1987-01-01

    Immunochemical methods are being developed to quantitate unique DNA base damages in x-irradiated DNA. The approach is to chemically synthesize modified nucleotides, conjugate them to protein carriers, and use the conjugates as immunogens in rabbits. Several thymine ring saturation or fragmentation products have been chosen as models for pyrimidine radiolysis products. These include thymine glycol, dihydrothymine and urea. The characterized antibodies are used to quantitate DNA damage x-irradiated in vitro and to immunochemically characterize the antibody to dihydrothymine. 12 refs., 1 fig., 1 tab

  14. Influence of gamma radiation on the immunological and immunochemical properties of cholera

    International Nuclear Information System (INIS)

    Nedugova, G.I.; Rubtsov, I.V.; Samojlenko, I.I.

    1984-01-01

    Results of studying the effect of gamma-radiation on immunochemical properties and serologic activity of unpurified cholera exotoxin are presented. It is found that in irradiated toxin preparations physico-chemical alterations take place as the dose of ionizing radiation increases, which brings about the increase in electrophoretic mobility, aggregation of protein components. It is shown that serologic activity contained in antigene toxin preparations retains within the limits of radiation doses studied

  15. Primary care visit use after positive fecal immunochemical test for colorectal cancer screening.

    Science.gov (United States)

    Hillyer, Grace Clarke; Jensen, Christopher D; Zhao, Wei K; Neugut, Alfred I; Lebwohl, Benjamin; Tiro, Jasmin A; Kushi, Lawrence H; Corley, Douglas A

    2017-10-01

    For some patients, positive cancer screening test results can be a stressful experience that can affect future screening compliance and increase the use of health care services unrelated to medically indicated follow-up. Among 483,216 individuals aged 50 to 75 years who completed a fecal immunochemical test to screen for colorectal cancer at a large integrated health care setting between 2007 and 2011, the authors evaluated whether a positive test was associated with a net change in outpatient primary care visit use within the year after screening. Multivariable regression models were used to evaluate the relationship between test result group and net changes in primary care visits after fecal immunochemical testing. In the year after the fecal immunochemical test, use increased by 0.60 clinic visits for patients with true-positive results. The absolute change in visits was largest (3.00) among individuals with positive test results who were diagnosed with colorectal cancer, but significant small increases also were found for patients treated with polypectomy and who had no neoplasia (0.36) and those with a normal examination and no polypectomy performed (0.17). Groups of patients who demonstrated an increase in net visit use compared with the true-negative group included patients with true-positive results (odds ratio [OR], 1.60; 95% confidence interval [95% CI], 1.54-1.66), and positive groups with a colorectal cancer diagnosis (OR, 7.19; 95% CI, 6.12-8.44), polypectomy/no neoplasia (OR, 1.37; 95% CI, 1.27-1.48), and normal examination/no polypectomy (OR, 1.24; 95% CI, 1.18-1.30). Given the large size of outreach programs, these small changes can cumulatively generate thousands of excess visits and have a substantial impact on total health care use. Therefore, these changes should be included in colorectal cancer screening cost models and their causes investigated further. Cancer 2017;123:3744-3753. © 2017 American Cancer Society. © 2017 American Cancer Society.

  16. Introduction to international radio regulations

    Energy Technology Data Exchange (ETDEWEB)

    Radicella, S M [Abdus Salam International Centre for Theoretical Physics, Trieste (Italy)

    2003-12-15

    These lecture notes contain an overview of basic problems of the International Radio Regulations. Access to the existing information infrastructure, and to that of the future Information Society, depends critically on radio, especially in poor, remote and sparsely populated regions with under-developed telecommunication infrastructure. How the spectrum of radio frequencies is regulated has profound impact on the society, its security, prosperity, and culture. The radio regulations represent a very important framework for an adequate use of radio and should be known by all of those working in the field.

  17. Introduction to international radio regulations

    International Nuclear Information System (INIS)

    Radicella, S.M.

    2003-01-01

    These lecture notes contain an overview of basic problems of the International Radio Regulations. Access to the existing information infrastructure, and to that of the future Information Society, depends critically on radio, especially in poor, remote and sparsely populated regions with under-developed telecommunication infrastructure. How the spectrum of radio frequencies is regulated has profound impact on the society, its security, prosperity, and culture. The radio regulations represent a very important framework for an adequate use of radio and should be known by all of those working in the field

  18. Ionosphere and Radio Communication

    Indian Academy of Sciences (India)

    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 ...

  19. 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....

  20. La radio en África. Una radio para el desarrollo

    Directory of Open Access Journals (Sweden)

    Jean-Paul Lafrance

    2015-01-01

    Full Text Available La radio de tipo comunitario, tal como la conocemos en Norteamérica y Europa (no-comercial, no-estatal y particípatíva, no existe en Africa. Sin embargo, la situación histórica y el contexto socio-político particulares de Africa han precedido la instauración de una radio que, dentro del marco del presente estudio, nos ha resultado interesante. Se trata de la radio educativa rural. Aunque enmarcada dentro del molde estatal de regímenes que en su mayoría son dictaduras, la radio rural africana, al igual que las radios de tipo comunitario, utiliza la radio con otros fines además de los convencionales. En este caso, la radio es un instrumento al servicio del desarrollo, por no decir al servicio del campesino, en una relación con éste último que probablemente dejará cada vez más de ser uni-direccional. La experiencia africana nos proporcionará en esta perspectiva nuevos elementos de reflexión en lo que respecta al rol de la radio dentro de la comunidad y sobre las condiciones incluso del éxito o no-éxito de la participación popular.

  1. 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.

  2. Main stages in the development of radiation immunology: from immunochemical analysis of injury to monitored radiotherapy

    International Nuclear Information System (INIS)

    Yarilin, A.A.; Kashkin, K.P.

    1982-01-01

    The results of research of the radiation action on immunity are presented. The results of immunochemical investigation of radiation tissue injuries are considered. Much attention is given to the problem of radiation injury and repair of the lymphoid system. It is shown that the next stage of development of radiation immunology is immunologic control of radiotherapy of oncologic patients

  3. Faecal immunochemical tests to triage patients with lower abdominal symptoms for suspected colorectal cancer referrals in primary care: a systematic review and cost-effectiveness analysis.

    Science.gov (United States)

    Westwood, Marie; Corro Ramos, Isaac; Lang, Shona; Luyendijk, Marianne; Zaim, Remziye; Stirk, Lisa; Al, Maiwenn; Armstrong, Nigel; Kleijnen, Jos

    2017-05-01

    Colorectal cancer (CRC) is the third most common cancer in the UK. Presenting symptoms that can be associated with CRC usually have another explanation. Faecal immunochemical tests (FITs) detect blood that is not visible to the naked eye and may help to select patients who are likely to benefit from further investigation. To assess the effectiveness of FITs [OC-Sensor (Eiken Chemical Co./MAST Diagnostics, Tokyo, Japan), HM-JACKarc (Kyowa Medex/Alpha Laboratories Ltd, Tokyo, Japan), FOB Gold (Sentinel/Sysmex, Sentinel Diagnostics, Milan, Italy), RIDASCREEN Hb or RIDASCREEN Hb/Hp complex (R-Biopharm, Darmstadt, Germany)] for primary care triage of people with low-risk symptoms. Twenty-four resources were searched to March 2016. Review methods followed published guidelines. Summary estimates were calculated using a bivariate model or a random-effects logistic regression model. The cost-effectiveness analysis considered long-term costs and quality-adjusted life-years (QALYs) that were associated with different faecal occult blood tests and direct colonoscopy referral. Modelling comprised a diagnostic decision model, a Markov model for long-term costs and QALYs that were associated with CRC treatment and progression, and a Markov model for QALYs that were associated with no CRC. We included 10 studies. Using a single sample and 10 µg Hb/g faeces threshold, sensitivity estimates for OC-Sensor [92.1%, 95% confidence interval (CI) 86.9% to 95.3%] and HM-JACKarc (100%, 95% CI 71.5% to 100%) indicated that both may be useful to rule out CRC. Specificity estimates were 85.8% (95% CI 78.3% to 91.0%) and 76.6% (95% CI 72.6% to 80.3%). Triage using FITs could rule out CRC and avoid colonoscopy in approximately 75% of symptomatic patients. Data from our systematic review suggest that 22.5-93% of patients with a positive FIT and no CRC have other significant bowel pathologies. The results of the base-case analysis suggested minimal difference in QALYs between all of the

  4. Affirmation of triggered Jovian radio emissions and their attribution to corotating radio lasers

    Science.gov (United States)

    Calvert, W.

    1985-01-01

    It is argued that the original statistical evidence for the existence of triggered radio emissions and corotating radio lasers on Jupiter remains valid notwithstanding the critique of Desch and Kaiser (1985). The Voyager radio spectrograms used to identify the triggered emissions are analyzed and the results are discussed. It is shown that the critique by Desch and Kaiser is unjustified because it is not based on the original event criteria, i.e., the correlation between the occurrence of Jovian auroral kilometric radiation and fast-drift type III solar bursts in the same frequency.

  5. Introduction to international radio regulations

    Energy Technology Data Exchange (ETDEWEB)

    Struzak, R

    2003-12-15

    These notes introduce the ITU Radio Regulations and related UN and WTO agreements that specify how terrestrial and satellite radio should be used in all countries over the planet. Access to the existing information infrastructure, and to that of the future Information Society, depends critically on these regulations. The paper also discusses few problems related to the use of the radio frequencies and satellite orbits. The notes are extracted from a book under preparation, in which these issues are discussed in more detail. (author)

  6. Introduction to international radio regulations

    International Nuclear Information System (INIS)

    Struzak, R.

    2003-01-01

    These notes introduce the ITU Radio Regulations and related UN and WTO agreements that specify how terrestrial and satellite radio should be used in all countries over the planet. Access to the existing information infrastructure, and to that of the future Information Society, depends critically on these regulations. The paper also discusses few problems related to the use of the radio frequencies and satellite orbits. The notes are extracted from a book under preparation, in which these issues are discussed in more detail. (author)

  7. Immunochemical approach to the study of DNA repair. Proposed technical program and technical progress report

    International Nuclear Information System (INIS)

    1982-01-01

    A simple immunochemical assay to quantify DNA lesions is being developed in order to facilitate the study of DNA repair. Antibodies have been raised to 5,6-dihydroxy-dihydrothymine and to thymine dimers and these have been used to measure DNA damages produced by osmium tetroxide and ultraviolet light, respectively. An enzyme immunoassay has been developed and the sensitivity of this method will be compared to physical, enzymatic, and chemical methods using PM2 bacteriophage DNA. Finally DNA repair will be assayed in several model systems

  8. Low frequency radio observations of five rich clusters of galaxies

    International Nuclear Information System (INIS)

    Hanisch, R.J.; Erickson, W.C.

    1980-01-01

    Observations have been made at 43.0 and 73.8 MHz of five rich x-ray emitting clusters of galaxies: Abell 399/401, Abell 426 (the Perseus cluster), Abell 1367, Abell 1656 (the Coma cluster), and the Virgo cluster. A fan beam synthesis system has been used to search for extended radio emission, i.e., radio halos, in these clusters. Radio halos were detected in the Coma and Virgo clusters. No evidence was found for the existence of 3C84B, the halo source previously thought to exist in the Perseus cluster. If halo sources exist in Abell 399/401 or Abell 1367, they must be quite weak at frequencies less than 100 MHz. The observed sizes of the extended sources in Coma and Virgo imply that the rate of particle propagation away from strong radio galaxies greatly exceeds the Alfven velocity and is probably independent of particle energy

  9. Survey on Cloud Radio Access Network

    Directory of Open Access Journals (Sweden)

    Reeta Chhatani

    2016-01-01

    Full Text Available The existing wireless network will face the challenge of data tsunami in the near future. Densification of network will deal huge data traffic but will increase the interferences and network cost. At the same time, the existing wireless network is underutilized due to dynamic traffic. To deal with this adverse scenario, a change in the current network architecture is required. Based on virtualization, Cloud Radio Access Network (CRAN was proposed for wireless network. In CRAN the functionality of base station will be distributed into base band unit (BBU and remote radio heads (RRH which will achieve benefits of centralization. This paper presents a survey on CRAN centring on optimized resource allocation, energy efficiency and throughput maximization under fronthaul capacity. The existing solution and future opportunities in CRAN are also summarized.

  10. Development of an Intervention for implementing Immunochemical Faecal Occult Blood Test in General Practice

    DEFF Research Database (Denmark)

    Juul, Jakob Søgaard; Vedsted, Peter; Bro, Flemming

    2016-01-01

    Denne korte artikel handler om udviklingen af en intervention til implementering af immunochemical faecal occult blood test (iFOBT) i almen praksis. Artiklen gennemgår processen fra de tidlige udviklingsstadier, over pilot-testning og frem til de endelige justeringer før selve implementeringen blev...... vurdering og viden om patienten. Kombinationen af teori og praksis viste sig at være en god måde at sikre hurtig ibrugtagning af en ny test i almen praksis til at identificere potentielle tegn på tarmkræft hos patienter. Særligt pilot-testning af interventionen viste sig at være værdifuld, fordi den...

  11. 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.

  12. Radio Emission from Supernovae

    International Nuclear Information System (INIS)

    Weiler, Kurt W.; Panagia, Nino; Sramek, Richard A.; Van Dyk, Schuyler D.; Williams, Christopher L.; Stockdale, Christopher J.; Kelley, Matthew T.

    2009-01-01

    Study of radio supernovae over the past 27 years includes more than three dozen detected objects and more than 150 upper limits. From this work it is possible to identify classes of radio properties, demonstrate conformance to and deviations from existing models, estimate the density and structure of the circumstellar material and, by inference, the evolution of the presupernova stellar wind, and reveal the last stages of stellar evolution before explosion. It is also possible to detect ionized hydrogen along the line of sight, to demonstrate binary properties of the presupernova stellar system, and to detect dumpiness of the circumstellar material.

  13. The statistics of radio emission from quasars

    International Nuclear Information System (INIS)

    Peacock, J.A.; Miller, L.; Longair, M.S.; Edinburgh Univ.

    1986-01-01

    The radio properties of quasars have traditionally been discussed in terms of the radio-to-optical flux-density ratio R, implying a correlation between emission in these wavebands. It is here shown that, for bright quasars, this apparent correlation is largely due to an abrupt change in the radio properties of the quasar population near absolute magnitude Msub(B)=-24. It is suggested that this change in due to the existence of two classes of quasar with differing host galaxies: a proportion of quasars brighter than Msub(B)approx.=-24 lie in elliptical galaxies and thus generate powerful radio sources, while elliptical galaxies with weaker nuclear quasar components are classified as N-galaxies rather than quasars; quasars fainter than Msub(B)approx.=-24 lie in spiral galaxies and thus are high-luminosity analogues of radio-quiet Seyfert galaxies. (author)

  14. ON THE ORIGIN OF FANAROFF-RILEY CLASSIFICATION OF RADIO GALAXIES: DECELERATION OF SUPERSONIC RADIO LOBES

    International Nuclear Information System (INIS)

    Kawakatu, Nozomu; Kino, Motoki; Nagai, Hiroshi

    2009-01-01

    We argue that the origin of 'FRI/FRII dichotomy' - the division between Fanaroff-Riley class I (FRI) with subsonic lobes and class II (FRII) radio sources with supersonic lobes is sharp in the radio-optical luminosity plane (Owen-White diagram) - can be explained by the deceleration of advancing radio lobes. The deceleration is caused by the growth of the effective cross-sectional area of radio lobes. We derive the condition in which an initially supersonic lobe turns into a subsonic lobe, combining the ram pressure equilibrium between the hot spots and the ambient medium with the relation between 'the hot spot radius' and 'the linear size of radio sources' obtained from the radio observations. We find that the dividing line between the supersonic lobes and subsonic ones is determined by the ratio of the jet power L j to the number density of the ambient matter at the core radius of the host galaxy n-bar a . It is also found that the maximal ratio of (L j ,n-bar a ) exists and its value resides in (L j ,n-bar a ) max ∼10 44-47 er s -1 cm 3 , taking into account considerable uncertainties. This suggests that the maximal value (L j ,n-bar a ) max separates between FRIs and FRIIs.

  15. A generalized and parameterized interference model for cognitive radio networks

    KAUST Repository

    Mahmood, Nurul Huda; Yilmaz, Ferkan; Alouini, Mohamed-Slim

    2011-01-01

    For meaningful co-existence of cognitive radios with primary system, it is imperative that the cognitive radio system is aware of how much interference it generates at the primary receivers. This can be done through statistical modeling

  16. An immunochemical assay for 8,5'-cyclonucleotides in irradiated nucleic acids

    International Nuclear Information System (INIS)

    Fuciarelli, A.F.; Raleigh, J.A.

    1985-01-01

    The transfer of radiation damage initiated in the sugar phosphate backbone to a nucleotide base as exemplified by 8,5'-cyclonucleotide formation has been investigated in polyadenylic acid, native and heat-denatured DNA. Polyclonal antiserum was raised in rabbits with a protein-8,5'-cycloadenosine-5'monophosphate (8,5'-cycloAMP) conjugate prepared by the carbodiimide method. An indirect, enzyme-linked immunosorbent assay (ELISA) was developed with this antiserum to probe for 8,5'-cycloAMP formation. The assay can readily detect product formation in polyadenylic acid irradiated to a total dose of 1.0 krad in the absence of oxygen. Product formation in native or heat-denatured DNA irradiated in 0.1 M phosphate buffer (pH 7.00) in the absence of oxygen is detected after approximately 20 krads. The authors shall extend these studies to determine the utility of immunochemical assays for investigating the radiation chemistry of nucleic acids

  17. Cryoconite. An exotic radio-ecological delicacy

    International Nuclear Information System (INIS)

    Tieber, A.; Wilflinger, T.; Lettner, H.; Hubmer, A.K.; Bossew, P.; Sattler, B.

    2009-01-01

    Five years of research on the radio-ecology of cryconite, a sediment of mineral and organic compounds found on glacier surfaces and within glacier ice, has led to amazing insights into the properties of an environmental medium which has been neglegted almost completely previously. It has turned out that a surprising radio-ecological diversity exists on and within glaciers, apart from their quality as thrieving biotopes, also not known for long. This presentation summarizes results from different research projects related to high-Alpine radio-ecology: radionuclide inventories and spatial distributions of cryoconite, hypotheses about their origin and formation, their cycling on and within glaciers, and their role in glacier melting due to global warming. (orig.)

  18. Listen and talk full-duplex cognitive radio networks

    CERN Document Server

    Liao, Yun; Han, Zhu

    2016-01-01

    This brief focuses on the use of full-duplex radio in cognitive radio networks, presenting a novel spectrum sharing protocol that allows the secondary users to simultaneously sense and access the vacant spectrum. This protocol, called “Listen-and-talk” (LAT), is evaluated by both mathematical analysis and computer simulations in comparison with other existing protocols, including the listen-before-talk protocol. In addition to LAT-based signal processing and resource allocation, the brief discusses techniques such as spectrum sensing and dynamic spectrum access. The brief proposes LAT as a suitable access scheme for cognitive radio networks, which can support the quality-of-service requirements of these high priority applications. Fundamental theories and key techniques of cognitive radio networks are also covered. Listen and Talk: Full-duplex Cognitive Radio Networks is designed for researchers, developers, and professionals involved in cognitive radio networks. Advanced-level students studying signal pr...

  19. Simple simulation training system for short-wave radio station

    Science.gov (United States)

    Tan, Xianglin; Shao, Zhichao; Tu, Jianhua; Qu, Fuqi

    2018-04-01

    The short-wave radio station is a most important transmission equipment of our signal corps, but in the actual teaching process, which exist the phenomenon of fewer equipment and more students, making the students' short-wave radio operation and practice time is very limited. In order to solve the above problems, to carry out shortwave radio simple simulation training system development is very necessary. This project is developed by combining hardware and software to simulate the voice communication operation and signal principle of shortwave radio station, and can test the signal flow of shortwave radio station. The test results indicate that this system is simple operation, human-machine interface friendly and can improve teaching more efficiency.

  20. 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.

  1. Faecal immunochemical tests to triage patients with lower abdominal symptoms for suspected colorectal cancer referrals in primary care: A systematic review and cost-effectiveness analysis

    NARCIS (Netherlands)

    M. Westwood (Marie); I. Corro Ramos (Isaac); Lang, S. (Shona); M. Luyendijk (Marianne); Zaim, R. (Remziye); Stirk, L. (Lisa); M.J. Al (Maiwenn); N. Armstrong (Nigel); J. Kleijnen (Jos)

    2017-01-01

    textabstractBackground: Colorectal cancer (CRC) is the third most common cancer in the UK. Presenting symptoms that can be associated with CRC usually have another explanation. Faecal immunochemical tests (FITs) detect blood that is not visible to the naked eye and may help to select patients who

  2. Indoor Positioning with Radio Location Fingerprinting

    DEFF Research Database (Denmark)

    Kjærgaard, Mikkel Baun

    . A promising indoor positioning technique is radio-based location ngerprinting, having the major advantage of exploiting already existing radio infrastructures, like IEEE 802.11 or GSM, which avoids extra deployment costs and eort. The research goal of this thesis is to address the limitations of current...... indoor location ngerprinting systems. In particular the aim is to advance location ngerprinting techniques for the challenges of handling heterogeneous clients, scalability to many clients, and interference between communication and positioning. The wireless clients used for location ngerprinting...... are heterogeneous even when only considering clients for the same technology. The heterogeneity is due to dierent radios, antennas, and rmwares causing measurements for location ngerprinting not to be directly comparable among clients. Heterogeneity is a challenge for location ngerprinting because it severely...

  3. Immunochemical and biological properties of a mouse monoclonal antibody reactive to prunus necrotic ringspot ilarvirus.

    Science.gov (United States)

    Aebig, J A; Jordan, R L; Lawson, R H; Hsu, H T

    1987-01-01

    A monoclonal antibody reacting with prunus necrotic ringspot ilarvirus was tested in immunochemical studies, neutralization of infectivity assays, and by immuno-electron microscopy. The antibody was able to detect the 27,000 Mr coat protein of prunus necrotic ringspot ilarvirus in western blots and also detected all polypeptide fragments generated after incubation of whole virus with proteolytic enzymes. In neutralization of infectivity studies, the antibody blocked virus infectivity, although it did not precipitate the antigen in agar gel Ouchterlony double diffusion tests. Immuno-electron microscopy confirmed that the antibody coats virions but does not cause clumping. The antibody may be a useful tool for investigating coat protein-dependent initiation of ilarvirus infection.

  4. Immunochemical faecal occult blood tests have superior stability and analytical performance characteristics over guaiac-based tests in a controlled in vitro study.

    LENUS (Irish Health Repository)

    Lee, Chun Seng

    2011-06-01

    The aims of this study were (1) to determine the measurement accuracy of a widely used guaiac faecal occult blood test (gFOBT) compared with an immunochemical faecal occult blood test (iFOBT) during in vitro studies, including their analytical stability over time at ambient temperature and at 4°C; and (2) to compare analytical imprecision and other characteristics between two commercially available iFOBT methods.

  5. Optical emission line spectra of Seyfert galaxies and radio galaxies

    International Nuclear Information System (INIS)

    Osterbrock, D.E.

    1978-01-01

    Many radio galaxies have strong emission lines in their optical spectra, similar to the emission lines in the spectra of Seyfert galaxies. The range of ionization extends from [O I] and [N I] through [Ne V] and [Fe VII] to [Fe X]. The emission-line spectra of radio galaxies divide into two types, narrow-line radio galaxies whose spectra are indistinguishable from Seyfert 2 galaxies, and broad-line radio galaxies whose spectra are similar to Seyfert 1 galaxies. However on the average the broad-line radio galaxies have steeper Balmer decrements, stronger [O III] and weaker Fe II emission than the Seyfert 1 galaxies, though at least one Seyfert 1 galaxy not known to be a radio source has a spectrum very similar to typical broad-line radio galaxies. Intermediate-type Seyfert galaxies exist that show various mixtures of the Seyfert 1 and Seyfert 2 properties, and the narrow-line or Seyfert 2 property seems to be strongly correlated with radio emission. (Auth.)

  6. Immunochemical faecal occult blood test for colorectal cancer screening: a systematic review.

    Science.gov (United States)

    Syful Azlie, M F; Hassan, M R; Junainah, S; Rugayah, B

    2015-02-01

    A systematic review on the effectiveness and costeffectiveness of Immunochemical faecal occult IFOBT for CRC screening was carried out. A total of 450 relevant titles were identified, 41 abstracts were screened and 18 articles were included in the results. There was fair level of retrievable evidence to suggest that the sensitivity and specificity of IFOBT varies with the cut-off point of haemoglobin, whereas the diagnostic accuracy performance was influenced by high temperature and haemoglobin stability. A screening programme using IFOBT can be effective for prevention of advanced CRC and reduced mortality. There was also evidence to suggest that IFOBT is cost-effective in comparison with no screening, whereby a two-day faecal collection method was found to be costeffective as a means of screening for CRC. Based on the review, quantitative IFOBT method can be used in Malaysia as a screening test for CRC. The use of fully automated IFOBT assay would be highly desirable.

  7. AIDS radio triggers.

    Science.gov (United States)

    Elias, A M

    1991-07-01

    In April 1991, the Ethnic Communities' Council of NSW was granted funding under the Community AIDS Prevention and Education Program through the Department of Community Services and Health, to produce a series of 6x50 second AIDS radio triggers with a 10-second tag line for further information. The triggers are designed to disseminate culturally-sensitive information about HIV/AIDS in English, Italian, Greek, Spanish, Khmer, Turkish, Macedonian, Serbo-Croatian, Arabic, Cantonese, and Vietnamese, with the goal of increasing awareness and decreasing the degree of misinformation about HIV/AIDS among people of non-English-speaking backgrounds through radio and sound. The 6 triggers cover the denial that AIDS exists in the community, beliefs that words and feelings do not protect one from catching HIV, encouraging friends to be compassionate, compassion within the family, AIDS information for a young audience, and the provision of accurate and honest information on HIV/AIDS. The triggers are slated to be completed by the end of July 1991 and will be broadcast on all possible community, ethnic, and commercial radio networks across Australia. They will be available upon request in composite form with an information kit for use by health care professionals and community workers.

  8. RADIO SOURCE FEEDBACK IN GALAXY EVOLUTION

    International Nuclear Information System (INIS)

    Shabala, Stanislav; Alexander, Paul

    2009-01-01

    We present a galaxy evolution model which incorporates a physically motivated implementation of active galactic nucleus feedback. Intermittent jets inflate cocoons of radio plasma which then expand supersonically, shock heating the ambient gas. The model reproduces observed star formation histories to the highest redshifts for which reliable data exist, as well as the observed galaxy color bimodality. Intermittent radio source feedback also naturally provides a way of keeping the black hole and spheroid growth in step. We find possible evidence for a top-heavy initial mass function for z > 2, consistent with observations of element abundances, and submillimeter and Lyman break galaxy counts.

  9. 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

  10. The development of new diagnostic test-systems and improvement of the existed radio immunochemical kits in the industrial production conditions

    International Nuclear Information System (INIS)

    Abdukayumov, A.M.

    2002-04-01

    The highly effective method had been developed for HBsAg preparing and purification that allowed to use as the raw material a plasma of donors with low content of the target product and based on the application of the stepped fractionation by Ammonium Sulphate and affinity chromatography. The use efficiency of the produced HBsAg preparations had been shown for laboratory animals immunization with the purpose of antiserum production that was the intermediate product for component manufacture needed for high sensitive kit creation; for preparation of affinity immunosorbent with the purpose of highly specific anti-HBs preparing. The method had been developed for production of anti-HBs preparations with standard immunoreactivity from donkey serum by means of specific antibodies fractionation on affinity immunosorbent. The work was done to finish the method for 125 I incorporation into the monoclonal mouse antibody molecules resulting maximum high biological activity. It was determined that the highest quality provided by approach of the isotope introduction by means of Chloraimine T reagent. It had been developed and introduced into industrial production the modified highly sensitive kit 'IRMA-M-HBsAg- 125 I' for HBsAg detection in human blood serum with use of monoclonal antibodies with the help of which it was managed to increase the stability and sensitivity and to standardize the technology of the kit. The technology had been developed and completed the laboratory and clinical testing of the kits of reagents 'IRMA-M-HBsAg- 125 I', 'ELISA-HBsAg', 'Recombinant-anti-HCV-strip' that had shown the high specificity and reproduction of the analysis results. Immunoenzymetic kit 'ELISA-HBsAg' of the third generation for HBsAg detection in human blood serum with the sensitivity not less than 0.5 ng/ml was introduced into industrial production. It had been developed and introduced into industrial production the highly sensitive immunoenzymetic test-system 'Recombinant-anti-HCV-strip' of the third generation for antibodies to hepatitis C virus detection in human blood serum

  11. Spectrum Utilisation and Management in Cognitive Radio Networks

    DEFF Research Database (Denmark)

    Patil, Kishor P.

    have confirmed this by showing that the considerable amount of radio spectrum is underutilized. Dynamic Spectrum Access (DSA) and the spectrum refarming are the two viable solutions for the problem of spectrum scarcity. In DSA, unlicensed user opportunistically uses the vacant licensed spectrum...... of licensed spectrum provides efficient use of spectrum. Spectrum refarming means the recovery of spectrum from its existing users for the purpose of re-assignment, either for new uses, or for the introduction of new spectrally efficient technologies. Spectrum refarming is a spectrum management tool that can......In recent years, the demand for radio spectrum for wireless communication is growing due to increase in number of users and popularity of data and multimedia services. This has been observed in the recent auctions completed word wide for the vestige of radio spectrum. The radio spectrum has been...

  12. Cognitive Radio Wireless Sensor Networks: Applications, Challenges and Research Trends

    Science.gov (United States)

    Joshi, Gyanendra Prasad; Nam, Seung Yeob; Kim, Sung Won

    2013-01-01

    A cognitive radio wireless sensor network is one of the candidate areas where cognitive techniques can be used for opportunistic spectrum access. Research in this area is still in its infancy, but it is progressing rapidly. The aim of this study is to classify the existing literature of this fast emerging application area of cognitive radio wireless sensor networks, highlight the key research that has already been undertaken, and indicate open problems. This paper describes the advantages of cognitive radio wireless sensor networks, the difference between ad hoc cognitive radio networks, wireless sensor networks, and cognitive radio wireless sensor networks, potential application areas of cognitive radio wireless sensor networks, challenges and research trend in cognitive radio wireless sensor networks. The sensing schemes suited for cognitive radio wireless sensor networks scenarios are discussed with an emphasis on cooperation and spectrum access methods that ensure the availability of the required QoS. Finally, this paper lists several open research challenges aimed at drawing the attention of the readers toward the important issues that need to be addressed before the vision of completely autonomous cognitive radio wireless sensor networks can be realized. PMID:23974152

  13. Cognitive Radio Wireless Sensor Networks: Applications, Challenges and Research Trends

    Directory of Open Access Journals (Sweden)

    Gyanendra Prasad Joshi

    2013-08-01

    Full Text Available A cognitive radio wireless sensor network is one of the candidate areas where cognitive techniques can be used for opportunistic spectrum access. Research in this area is still in its infancy, but it is progressing rapidly. The aim of this study is to classify the existing literature of this fast emerging application area of cognitive radio wireless sensor networks, highlight the key research that has already been undertaken, and indicate open problems. This paper describes the advantages of cognitive radio wireless sensor networks, the difference between ad hoc cognitive radio networks, wireless sensor networks, and cognitive radio wireless sensor networks, potential application areas of cognitive radio wireless sensor networks, challenges and research trend in cognitive radio wireless sensor networks. The sensing schemes suited for cognitive radio wireless sensor networks scenarios are discussed with an emphasis on cooperation and spectrum access methods that ensure the availability of the required QoS. Finally, this paper lists several open research challenges aimed at drawing the attention of the readers toward the important issues that need to be addressed before the vision of completely autonomous cognitive radio wireless sensor networks can be realized.

  14. Cognitive radio wireless sensor networks: applications, challenges and research trends.

    Science.gov (United States)

    Joshi, Gyanendra Prasad; Nam, Seung Yeob; Kim, Sung Won

    2013-08-22

    A cognitive radio wireless sensor network is one of the candidate areas where cognitive techniques can be used for opportunistic spectrum access. Research in this area is still in its infancy, but it is progressing rapidly. The aim of this study is to classify the existing literature of this fast emerging application area of cognitive radio wireless sensor networks, highlight the key research that has already been undertaken, and indicate open problems. This paper describes the advantages of cognitive radio wireless sensor networks, the difference between ad hoc cognitive radio networks, wireless sensor networks, and cognitive radio wireless sensor networks, potential application areas of cognitive radio wireless sensor networks, challenges and research trend in cognitive radio wireless sensor networks. The sensing schemes suited for cognitive radio wireless sensor networks scenarios are discussed with an emphasis on cooperation and spectrum access methods that ensure the availability of the required QoS. Finally, this paper lists several open research challenges aimed at drawing the attention of the readers toward the important issues that need to be addressed before the vision of completely autonomous cognitive radio wireless sensor networks can be realized.

  15. Mobile radio alternative systems study traffic model

    Science.gov (United States)

    Tucker, W. T.; Anderson, R. E.

    1983-06-01

    The markets for mobile radio services in non-urban areas of the United States are examined for the years 1985-2000. Three market categories are identified. New Services are defined as those for which there are different expressed ideas but which are not now met by any application of available technology. The complete fulfillment of the needs requires nationwide radio access to vehicles without knowledge of vehicle location, wideband data transmission from remote sites, one- and two way exchange of short data and control messages between vehicles and dispatch or control centers, and automatic vehicle location (surveillance). The commercial and public services market of interest to the study is drawn from existing users of mobile radio in non-urban areas who are dissatisfied with the geographical range or coverage of their systems. The mobile radio telephone market comprises potential users who require access to the public switched telephone network in areas that are not likely to be served by the traditional growth patterns of terrestrial mobile telephone services. Conservative, likely, and optimistic estimates of the markets are presented in terms of numbers of vehicles that will be served and the radio traffic they will generate.

  16. Radio astronomy

    Energy Technology Data Exchange (ETDEWEB)

    Nagnibeda, V.G.

    1981-01-01

    The history of radio astronomical observations at the Astronomical Observatory of Leningrad State University is reviewed. Various facilities are described, and methods and instruments used are discussed. Some results are summarized for radio observations of the sun, including observations of local sources of solar radio emission, the absolute solar radio flux, and radio emission from filaments and prominences.

  17. Radio-loud magnetars as detectors for axions and axion-like particles

    International Nuclear Information System (INIS)

    Guendelman, E.I.; Chelouche, D.

    2011-01-01

    We show that, by studying the arrival times of radio pulses from highly-magnetized transient beamed sources, it may be possible to detect light pseudo-scalar particles, such as axions and axion-like particles, whose existence could have considerable implications for the strong-CP problem of QCD as well as the dark matter problem in cosmology. Specifically, such light bosons may be detected with a much greater sensitivity, over a broad particle mass range, than is currently achievable by terrestrial experiments, and using indirect astrophysical considerations. The observable effect was discussed in Chelouche & Guendelman (2009), and is akin to the Stern-Gerlach experiment: the splitting of a photon beam naturally arises when finite coupling exists between the electro-magnetic field and the axion field. The splitting angle of the light beams linearly depends on the photon wavelength, the size of the magnetized region, and the magnetic field gradient in the transverse direction to the propagation direction of the photons. If radio emission in radio-loud magnetars is beamed and originates in regions with strong magnetic field gradients, then splitting of individual pulses may be detectable. We quantify the effect for a simplified model for magnetars, and search for radio beam splitting in the 2GHz radio light curves of the radio loud magnetar XTEJ1810-197. (author)

  18. VLA radio observations of AR Scorpii

    Science.gov (United States)

    Stanway, E. R.; Marsh, T. R.; Chote, P.; Gänsicke, B. T.; Steeghs, D.; Wheatley, P. J.

    2018-03-01

    Aims: AR Scorpii is unique amongst known white dwarf binaries in showing powerful pulsations extending to radio frequencies. Here we aim to investigate the multi-frequency radio emission of AR Sco in detail, in order to constrain its origin and emission mechanisms. Methods: We present interferometric radio frequency imaging of AR Sco at 1.5, 5 and 9 GHz, analysing the total flux and polarization behaviour of this source at high time resolution (10, 3 and 3 s), across a full 3.6 h orbital period in each band. Results: We find strong modulation of the radio flux on the orbital period and the orbital sideband of the white dwarf's spin period (also known as the "beat" period). This indicates that, like the optical flux, the radio flux arises predominantly from on or near the inner surface of the M-dwarf companion star. The beat-phase pulsations of AR Sco decrease in strength with decreasing frequency. They are strongest at 9 GHz and at an orbital phase 0.5. Unlike the optical emission from this source, radio emission from AR Sco shows weak linear polarization but very strong circular polarization, reaching 30% at an orbital phase 0.8. We infer the probable existence of a non-relativistic cyclotron emission component, which dominates at low radio frequencies. Given the required magnetic fields, this also likely arises from on or near the M-dwarf. A table of the flux time series is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/611/A66

  19. An immunochemical approach to the study of DNA damage and repair

    International Nuclear Information System (INIS)

    Wallace, S.S.; Erlanger, B.F.

    1992-05-01

    The overall objective of this project has been to develop immunochemical methods to quantitate unique DNA base damages in order to facilitate studies on radiation-induced damage production and repair. Specifically, we have been using antibodies raised to damaged bases to quantitate unique lesions in model systems in order to evaluate their potential biological consequences. Our approach has been to synthesize modified nucleotides or nucleosides, conjugate them to protein carriers, and use the conjugates as immunogens in rabbits or to prepare monoclonal antibodies. We have been studying damages that are stable radiolysis products found in X-irradiated DNA and thus of potential biological consequence. Our aim is to build an in vitro and in vivo data base on the interactions between model DNA lesions and such cellular enzymes as DNA polymerases and repair endonucleases. Initial studies have focused on pyrimidine ring saturation products (thymine glycol.and dihydrothymine), products resulting from ring fragmentation or base loss (urea, Β-ureidoisobutyric acid, abasic sites), 7-hydro-8-oxopurines, and more recently, cytosine radiolysis products. These modified bases serve as useful models for examining the potential lethal and/or mutagenic (carcinogenic) effects of the products of DNA radiolysis

  20. Radio and white-light observations of coronal transients

    International Nuclear Information System (INIS)

    Dulk, G.A.

    1980-01-01

    Optical, radio and X-ray evidence of violent mass motions in the corona has existed for some years but only recently have the form, nature, frequency and implication of the transients become obvious. The author reviews the observed properties of coronal transients, concentrating on the white-light and radio manifestations. The classification according to speeds seems to be meaningful, with the slow transients having thermal emissions at radio wavelengths and the fast ones non-thermal. The possible mechanisms involved in the radio bursts are discussed and the estimates of various forms of energy are reviewed. It appears that the magnetic energy transported from the Sun by the transient exceeds that of any other form, and that magnetic forces dominate in the dynamics of the motions. The conversion of magnetic energy into mechanical energy, by expansion of the fields, provides a possible driving force for the coronal and interplanetary shock waves. (Auth.)

  1. The host galaxy of a fast radio burst.

    Science.gov (United States)

    Keane, E F; Johnston, S; Bhandari, S; Barr, E; Bhat, N D R; Burgay, M; Caleb, M; Flynn, C; Jameson, A; Kramer, M; Petroff, E; Possenti, A; van Straten, W; Bailes, M; Burke-Spolaor, S; Eatough, R P; Stappers, B W; Totani, T; Honma, M; Furusawa, H; Hattori, T; Morokuma, T; Niino, Y; Sugai, H; Terai, T; Tominaga, N; Yamasaki, S; Yasuda, N; Allen, R; Cooke, J; Jencson, J; Kasliwal, M M; Kaplan, D L; Tingay, S J; Williams, A; Wayth, R; Chandra, P; Perrodin, D; Berezina, M; Mickaliger, M; Bassa, C

    2016-02-25

    In recent years, millisecond-duration radio signals originating in distant galaxies appear to have been discovered in the so-called fast radio bursts. These signals are dispersed according to a precise physical law and this dispersion is a key observable quantity, which, in tandem with a redshift measurement, can be used for fundamental physical investigations. Every fast radio burst has a dispersion measurement, but none before now have had a redshift measurement, because of the difficulty in pinpointing their celestial coordinates. Here we report the discovery of a fast radio burst and the identification of a fading radio transient lasting ~6 days after the event, which we use to identify the host galaxy; we measure the galaxy's redshift to be z = 0.492 ± 0.008. The dispersion measure and redshift, in combination, provide a direct measurement of the cosmic density of ionized baryons in the intergalactic medium of ΩIGM = 4.9 ± 1.3 per cent, in agreement with the expectation from the Wilkinson Microwave Anisotropy Probe, and including all of the so-called 'missing baryons'. The ~6-day radio transient is largely consistent with the radio afterglow of a short γ-ray burst, and its existence and timescale do not support progenitor models such as giant pulses from pulsars, and supernovae. This contrasts with the interpretation of another recently discovered fast radio burst, suggesting that there are at least two classes of bursts.

  2. An overview and guide: planning instructional radio.

    Science.gov (United States)

    Imhoof, M

    1984-03-01

    activities utilized in broadcasts which are contrary to the learners' experience will at best seem strange and at worst be incomprehensible. Curriculum development in an instructional radio project adds more complexity to the planner's task. The most important information needed is whether a new curriculum is to be developed or whether the existing curriculum is to be adapted for radio. Another major analysis task is relating the curriculum to the medium. The project planning team needs to understand the research aims and evaluation methods in instructional radio projects. Sometimes an outside evaluation specialist or team is employed, but in many projects the planning team is responsible for implementing the research design, carrying out the development activities, gathering data, and evaluating the project. Subject matter testing is another technical area of expertise needed by the project team.

  3. Advances in solar radio astronomy

    Science.gov (United States)

    Kundu, M. R.

    1982-01-01

    The status of the observations and interpretations of the sun's radio emission covering the entire radio spectrum from millimeter wavelengths to hectometer and kilometer wavelengths is reviewed. Emphasis is given to the progress made in solar radio physics as a result of recent advances in plasma and radiation theory. It is noted that the capability now exists of observing the sun with a spatial resolution of approximately a second of arc and a temporal resolution of about a millisecond at centimeter wavelengths and of obtaining fast multifrequency two-dimensional pictures of the sun at meter and decameter wavelengths. A summary is given of the properties of nonflaring active regions at millimeter, centimeter, and meter-decameter wavelengths. The properties of centimeter wave bursts are discussed in connection with the high spatial resolution observations. The observations of the preflare build-up of an active region are reviewed. High spatial resolution observations (a few seconds of arc to approximately 1 arcsec) are discussed, with particular attention given to the one- and two-dimensional maps of centimeter-wavelength burst sources.

  4. Radio stars

    International Nuclear Information System (INIS)

    Hjellming, R.M.

    1976-01-01

    Any discussion of the radio emission from stars should begin by emphasizing certain unique problems. First of all, one must clarify a semantic confusion introduced into radio astronomy in the late 1950's when most new radio sources were described as radio stars. All of these early 'radio stars' were eventually identified with other galactic and extra-galactic objects. The study of true radio stars, where the radio emission is produced in the atmosphere of a star, began only in the 1960's. Most of the work on the subject has, in fact, been carried out in only the last few years. Because the real information about radio stars is quite new, it is not surprising that major aspects of the subject are not at all understood. For this reason this paper is organized mainly around three questions: what is the available observational information; what physical processes seem to be involved; and what working hypotheses look potentially fruitful. (Auth.)

  5. A generalized and parameterized interference model for cognitive radio networks

    KAUST Repository

    Mahmood, Nurul Huda

    2011-06-01

    For meaningful co-existence of cognitive radios with primary system, it is imperative that the cognitive radio system is aware of how much interference it generates at the primary receivers. This can be done through statistical modeling of the interference as perceived at the primary receivers. In this work, we propose a generalized model for the interference generated by a cognitive radio network, in the presence of small and large scale fading, at a primary receiver located at the origin. We then demonstrate how this model can be used to estimate the impact of cognitive radio transmission on the primary receiver in terms of different outage probabilities. Finally, our analytical findings are validated through some selected computer-based simulations. © 2011 IEEE.

  6. Radio and white-light observations of coronal transients

    Science.gov (United States)

    Dulk, G. A.

    1980-01-01

    Optical, radio and X-ray evidence of violent mass motions in the corona has existed for some years but only recently have the form, nature, frequency and implication of the transients become obvious. In this paper the observed properties of coronal transients are reviewed, with concentration on the white-light and radio manifestations. The classification according to speeds seems to be meaningful, with the slow transients having thermal emissions at radio wavelengths and the fast ones nonthermal. The possible mechanisms involved in the radio bursts are then discussed and estimates of various forms of energy are reviewed. It appears that the magnetic energy transported from the sun by the transient exceeds that of any other form, and that magnetic forces dominate in the dynamics of the motions. The conversion of magnetic energy into mechanical energy, by expansion of the field, provides a possible driving force for the coronal and interplanetary shock waves.

  7. Particle acceleration by Alfven wave turbulence in radio galaxies

    International Nuclear Information System (INIS)

    Eilek, J.A.

    1986-01-01

    Radio galaxies show evidence for acceleration of relativistic electrons locally within the diffuse radio luminous plasma. One likely candidate for the reacceleration mechanism is acceleration by magnetohydrodynamic turbulence which exists within the plasma. If Alfven waves are generated by a fluid turbulent cascade described by a power law energy-wavenumber spectrum, the particle spectrum in the presence of synchrotron losses will evolve towards an asymptotic power law which agrees with the particle spectra observed in these sources

  8. Classifying Radio Galaxies with the Convolutional Neural Network

    Energy Technology Data Exchange (ETDEWEB)

    Aniyan, A. K.; Thorat, K. [Department of Physics and Electronics, Rhodes University, Grahamstown (South Africa)

    2017-06-01

    We present the application of a deep machine learning technique to classify radio images of extended sources on a morphological basis using convolutional neural networks (CNN). In this study, we have taken the case of the Fanaroff–Riley (FR) class of radio galaxies as well as radio galaxies with bent-tailed morphology. We have used archival data from the Very Large Array (VLA)—Faint Images of the Radio Sky at Twenty Centimeters survey and existing visually classified samples available in the literature to train a neural network for morphological classification of these categories of radio sources. Our training sample size for each of these categories is ∼200 sources, which has been augmented by rotated versions of the same. Our study shows that CNNs can classify images of the FRI and FRII and bent-tailed radio galaxies with high accuracy (maximum precision at 95%) using well-defined samples and a “fusion classifier,” which combines the results of binary classifications, while allowing for a mechanism to find sources with unusual morphologies. The individual precision is highest for bent-tailed radio galaxies at 95% and is 91% and 75% for the FRI and FRII classes, respectively, whereas the recall is highest for FRI and FRIIs at 91% each, while the bent-tailed class has a recall of 79%. These results show that our results are comparable to that of manual classification, while being much faster. Finally, we discuss the computational and data-related challenges associated with the morphological classification of radio galaxies with CNNs.

  9. Classifying Radio Galaxies with the Convolutional Neural Network

    Science.gov (United States)

    Aniyan, A. K.; Thorat, K.

    2017-06-01

    We present the application of a deep machine learning technique to classify radio images of extended sources on a morphological basis using convolutional neural networks (CNN). In this study, we have taken the case of the Fanaroff-Riley (FR) class of radio galaxies as well as radio galaxies with bent-tailed morphology. We have used archival data from the Very Large Array (VLA)—Faint Images of the Radio Sky at Twenty Centimeters survey and existing visually classified samples available in the literature to train a neural network for morphological classification of these categories of radio sources. Our training sample size for each of these categories is ˜200 sources, which has been augmented by rotated versions of the same. Our study shows that CNNs can classify images of the FRI and FRII and bent-tailed radio galaxies with high accuracy (maximum precision at 95%) using well-defined samples and a “fusion classifier,” which combines the results of binary classifications, while allowing for a mechanism to find sources with unusual morphologies. The individual precision is highest for bent-tailed radio galaxies at 95% and is 91% and 75% for the FRI and FRII classes, respectively, whereas the recall is highest for FRI and FRIIs at 91% each, while the bent-tailed class has a recall of 79%. These results show that our results are comparable to that of manual classification, while being much faster. Finally, we discuss the computational and data-related challenges associated with the morphological classification of radio galaxies with CNNs.

  10. Classifying Radio Galaxies with the Convolutional Neural Network

    International Nuclear Information System (INIS)

    Aniyan, A. K.; Thorat, K.

    2017-01-01

    We present the application of a deep machine learning technique to classify radio images of extended sources on a morphological basis using convolutional neural networks (CNN). In this study, we have taken the case of the Fanaroff–Riley (FR) class of radio galaxies as well as radio galaxies with bent-tailed morphology. We have used archival data from the Very Large Array (VLA)—Faint Images of the Radio Sky at Twenty Centimeters survey and existing visually classified samples available in the literature to train a neural network for morphological classification of these categories of radio sources. Our training sample size for each of these categories is ∼200 sources, which has been augmented by rotated versions of the same. Our study shows that CNNs can classify images of the FRI and FRII and bent-tailed radio galaxies with high accuracy (maximum precision at 95%) using well-defined samples and a “fusion classifier,” which combines the results of binary classifications, while allowing for a mechanism to find sources with unusual morphologies. The individual precision is highest for bent-tailed radio galaxies at 95% and is 91% and 75% for the FRI and FRII classes, respectively, whereas the recall is highest for FRI and FRIIs at 91% each, while the bent-tailed class has a recall of 79%. These results show that our results are comparable to that of manual classification, while being much faster. Finally, we discuss the computational and data-related challenges associated with the morphological classification of radio galaxies with CNNs.

  11. Superconducting Radio-Frequency Cavities

    Science.gov (United States)

    Padamsee, Hasan S.

    2014-10-01

    Superconducting cavities have been operating routinely in a variety of accelerators with a range of demanding applications. With the success of completed projects, niobium cavities have become an enabling technology, offering upgrade paths for existing facilities and pushing frontier accelerators for nuclear physics, high-energy physics, materials science, and the life sciences. With continued progress in basic understanding of radio-frequency superconductivity, the performance of cavities has steadily improved to approach theoretical capabilities.

  12. Competence and lastingness in specialized clinical laboratories: technical report about requirements concerning quality of users competence and used processes in immunochemical diagnostic procedures using isotopic and non-isotopic tracer technologies

    International Nuclear Information System (INIS)

    Wiegel, B.

    2005-01-01

    From the citizens view this technical report about immunochemical diagnostic procedures using radioactive and nonradioactive tracer technologies describes the requirements in special laboratory diagnostics concerning competency and process control. Governmental or administrational obligations of inspecting both skill and sites to guarantee patients security are pointed out. (orig.)

  13. Immunochemical and ultrastructural assessment of the nature of the pericellular basement membrane of human decidual cells

    DEFF Research Database (Denmark)

    Wewer, U M; Faber, M; Liotta, L A

    1985-01-01

    Human decidual cells of early and late pregnancy were studied immunochemically and ultrastructurally with respect to the presence and nature of pericellular basement membrane material. The most prominent cell type in decidual tissue of both early and late pregnancy were large, mature epithelioid......-linked immunosorbent assay. Biosynthesis of laminin was shown by [35S]methionine labeling of short term organ cultures of decidual tissue followed by immunoprecipation, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and fluorography. The laminin chains migrated with the apparent molecular weights of 300...... and 200 kilodaltons under reducing conditions. Two other separate populations of cells were apparent in the decidual tissue of early pregnancy. A smaller group of rounded intermediate sized (15 to 25 micron) decidual cells had focal deposits basement membrane immunoreactive material scattered at the cell...

  14. Radio stars

    International Nuclear Information System (INIS)

    Hjellming, R.M.; Gibson, D.M.

    1985-01-01

    Studies of stellar radio emission became an important field of research in the 1970's and have now expanded to become a major area of radio astronomy with the advent of new instruments such as the Very Large Array in New Mexico and transcontinental telescope arrays. This volume contains papers from the workshop on stellar continuum radio astronomy held in Boulder, Colorado, and is the first book on the rapidly expanding field of radio emission from stars and stellar systems. Subjects covered include the observational and theoretical aspects of stellar winds from both hot and cool stars, radio flares from active double star systems and red dwarf stars, bipolar flows from star-forming regions, and the radio emission from X-ray binaries. (orig.)

  15. IRAS observations of radio-quiet and radio-loud quasars

    Science.gov (United States)

    Neugebauer, G.; Soifer, B. T.; Miley, G.; Habing, H. J.; Young, E.; Low, F. J.; Beichman, C. A.; Clegg, P. E.; Harris, S.; Rowan-Robinson, M.

    1984-01-01

    Observations from 12 to 100 microns are presented of two radio-quiet and three radio-loud quasars. Over this wavelength range, all five have grossly similar continuum energy distributions. The continua of the radio-loud quasars are consistent with synchrotron radiation. There is an indication, however, of excess 100 micron emission in the two radio-quiet quasars.

  16. Results of faecal immunochemical test for colorectal cancer screening, in average risk population, in a cohort of 1389 subjects.

    Science.gov (United States)

    Miuţescu, Bogdan; Sporea, Ioan; Popescu, Alina; Bota, Simona; Iovănescu, Dana; Burlea, Amelia; Mos, Liana; Miuţescu, Eftimie

    2013-01-01

    The aim of this study is to evaluate the usefulness of the fecal immunochemical test (FIT) in colorectal cancer screening, detection of precancerous lesions and early colorectal cancer. The study evaluated asymptomatic patients with average risk (no personal or family antecedents of polyps or colorectal cancer), aged between 50 and 74 years. The presence of the occult haemorrhage was tested with the immunochemical faecal test Hem Check 1 (Veda Lab, France). The subjects were not requested to have any dietary or drug restrictions. Colonoscopy was recommended in all subjects that tested positive. In our study, we had a total of 1389 participants who met the inclusion criteria, with a mean age of 61.2 ± 12.8 years, 565 (40.7%) men and 824 (59.3%) women. FIT was positive in 87 individuals (6.3%). In 57/87 subjects (65.5%) with positive FIT, colonoscopy was performed, while the rest of the subjects refused or delayed the investigation. A number of 5 (8.8%) patients were not able to have a complete colonoscopy, due to neoplastic stenosis. The colonoscopies revealed in 10 cases (0.7%) cancer, in 29 cases (2.1%) advanced adenomas and in 15 cases (1.1%) non advanced adenomas from the total participants in the study. The colonoscopies performed revealed a greater percentage of advanced adenomas in the left colon compared to the right colon, 74.1% vs. 28.6% (p<0.001). In our study, FIT had a positivity rate of 6.3%. The detection rate for advanced neoplasia was 2.8% (0.7% for cancer, 2.1% for advanced adenomas) in our study group. Adherence to colonoscopy for FIT-positive subjects was 65.5%.

  17. Sensitive measurement of endotoxin by radio-rocket immunoelectrophoresis using [125I]Staphylococcus aureus protein A

    International Nuclear Information System (INIS)

    Stevens, P.; Alam, S.; Young, L.S.; Chesebro, K.

    1981-01-01

    Antibody directed against the core glycolipid antigen (CGL) of the mutant Salmonella minnesota Re 595 has been shown to cross-react with endotoxin from bacteria within the group Enterobacteriaceae. Using this cross-reactive CGL antibody the authors have developed a sensitive (250 pg) radio-rocket immunoelectrophoretic technique to measure endotoxin. They used the principles of rocket immunoelectrophoresis and increased the sensitivity by using 125 I-labelled staphylococcal protein A which serves as a sensitive probe to bind to the Fc portion of the IgG complexed with antigen. The rocket-shaped [ 125 I]protein A labelled immune complexes were detected by radioautography. The sensitivity is 100-fold greater than conventional Coomassie brilliant blue staining. Measurement of CGL was inhibited by normal human serum. However, the assay had the capacity to quantitate endotoxin in buffer extracts of clinically isolated Escherichia coli, Serratia marcescens, Klebsiella pneumoniae but not Pseudomonas aeruginosa. Analysis of various preparations of CGL obtained from different investigators demonstrated wide variation in their immunoreactivity. Because of the significant cross-reaction to detect various endotoxins this method has the potential to measure endotoxemia and assess the immunochemical quality of various endotoxin preparations. Additionally, the techniques of using [ 125 I]protein A has wide applicability for the sensitive measurement of other antigens. (Auth.)

  18. The Jodrell Bank radio-linked interferometer network

    International Nuclear Information System (INIS)

    Davies, J.G.; Anderson, B.; Morison, I.

    1980-01-01

    The capabilities of the Multi Telescope Radio Linked Interferometer (MTRLI) situated at Jodrell Bank, are described and some of the first maps to be made with it are presented. MTRLI produces high quality maps of radio sources with resolutions varying from approximately 1 arc s to approximately 0.02 arc s depending on the frequency of operation. The maps presented here were made at 408 MHz and are all of extragalactic sources. They illustrate the ability of MTRLI to map at low frequencies the steep spectrum emission which tends to be overlooked with existing synthesis instruments which have to work at much higher frequencies to obtain the same resolution. (U.K.)

  19. RADIO EMISSION FROM RED-GIANT HOT JUPITERS

    International Nuclear Information System (INIS)

    Fujii, Yuka; Spiegel, David S.; Mroczkowski, Tony; Nordhaus, Jason; Zimmerman, Neil T.; Parsons, Aaron R.; Mirbabayi, Mehrdad; Madhusudhan, Nikku

    2016-01-01

    When planet-hosting stars evolve off the main sequence and go through the red-giant branch, the stars become orders of magnitudes more luminous and, at the same time, lose mass at much higher rates than their main-sequence counterparts. Accordingly, if planetary companions exist around these stars at orbital distances of a few au, they will be heated up to the level of canonical hot Jupiters and also be subjected to a dense stellar wind. Given that magnetized planets interacting with stellar winds emit radio waves, such “Red-Giant Hot Jupiters” (RGHJs) may also be candidate radio emitters. We estimate the spectral auroral radio intensity of RGHJs based on the empirical relation with the stellar wind as well as a proposed scaling for planetary magnetic fields. RGHJs might be intrinsically as bright as or brighter than canonical hot Jupiters and about 100 times brighter than equivalent objects around main-sequence stars. We examine the capabilities of low-frequency radio observatories to detect this emission and find that the signal from an RGHJ may be detectable at distances up to a few hundred parsecs with the Square Kilometer Array

  20. RADIO EMISSION FROM RED-GIANT HOT JUPITERS

    Energy Technology Data Exchange (ETDEWEB)

    Fujii, Yuka [Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo, 152-8550 (Japan); Spiegel, David S. [Analytics and Algorithms, Stitch Fix, San Francisco, CA 94103 (United States); Mroczkowski, Tony [Naval Research Laboratory, 4555 Overlook Ave SW, Washington, DC 20375 (United States); Nordhaus, Jason [Department of Science and Mathematics, National Technical Institute for the Deaf, Rochester Institute of Technology, Rochester, NY 14623 (United States); Zimmerman, Neil T. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Parsons, Aaron R. [Astronomy Department, University of California, Berkeley, CA (United States); Mirbabayi, Mehrdad [Astrophysics Department, Institute for Advanced Study, Princeton, NJ 08540 (United States); Madhusudhan, Nikku, E-mail: yuka.fujii@elsi.jp [Astronomy Department, University of Cambridge (United Kingdom)

    2016-04-01

    When planet-hosting stars evolve off the main sequence and go through the red-giant branch, the stars become orders of magnitudes more luminous and, at the same time, lose mass at much higher rates than their main-sequence counterparts. Accordingly, if planetary companions exist around these stars at orbital distances of a few au, they will be heated up to the level of canonical hot Jupiters and also be subjected to a dense stellar wind. Given that magnetized planets interacting with stellar winds emit radio waves, such “Red-Giant Hot Jupiters” (RGHJs) may also be candidate radio emitters. We estimate the spectral auroral radio intensity of RGHJs based on the empirical relation with the stellar wind as well as a proposed scaling for planetary magnetic fields. RGHJs might be intrinsically as bright as or brighter than canonical hot Jupiters and about 100 times brighter than equivalent objects around main-sequence stars. We examine the capabilities of low-frequency radio observatories to detect this emission and find that the signal from an RGHJ may be detectable at distances up to a few hundred parsecs with the Square Kilometer Array.

  1. Radio Emission from Red-Giant Hot Jupiters

    Science.gov (United States)

    Fujii, Yuka; Spiegel, David S.; Mroczkowski, Tony; Nordhaus, Jason; Zimmerman, Neil T.; Parsons, Aaron R.; Mirbabayi, Mehrdad; Madhusudhan, Nikku

    2016-01-01

    When planet-hosting stars evolve off the main sequence and go through the red-giant branch, the stars become orders of magnitudes more luminous and, at the same time, lose mass at much higher rates than their main sequence counterparts. Accordingly, if planetary companions exist around these stars at orbital distances of a few au, they will be heated up to the level of canonical hot Jupiters and also be subjected to a dense stellar wind. Given that magnetized planets interacting with stellar winds emit radio waves, such "Red-Giant Hot Jupiters" (RGHJs) may also be candidate radio emitters. We estimate the spectral auroral radio intensity of RGHJs based on the empirical relation with the stellar wind as well as a proposed scaling for planetary magnetic fields. RGHJs might be intrinsically as bright as or brighter than canonical hot Jupiters and about 100 times brighter than equivalent objects around main-sequence stars. We examine the capabilities of low-frequency radio observatories to detect this emission and find that the signal from an RGHJ may be detectable at distances up to a few hundred parsecs with the Square Kilometer Array.

  2. 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.

  3. Using Radio Irregularity for Increasing Residential Energy Awareness

    Directory of Open Access Journals (Sweden)

    A. Miljković

    2012-06-01

    Full Text Available Radio irregularity phenomenon is often considered as a shortcoming of wireless networks. In this paper, the method of using radio irregularity as an efficient human presence detection sensor in smart homes is presented. The method is mainly based on monitoring variations of the received signal strength indicator (RSSI within the messages used for the communication between wireless smart power outlets. The radio signals used for the inter-outlets communication can be absorbed, diffracted or reflected by objects in their propagation paths. When a human enters the existing radio communication field, the variation of the signal strength at the receiver is even more expressed. Based on the detected changes and compared to the initial thresholds set during the initialization phase, the system detects human presence. The proposed solution increases user awareness and automates the power control in households, with the primary goal to contribute in residential energy savings. Compared to conventional sensor networks, this approach preserves the sensorial intelligence, simplicity and low installation costs, without the need for additional sensors integration.

  4. The excess radio background and fast radio transients

    International Nuclear Information System (INIS)

    Kehayias, John; Kephart, Thomas W.; 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 contribute to the radio background

  5. Cost-effectiveness analysis of the optimal threshold of an automated immunochemical test for colorectal cancer screening: performances of immunochemical colorectal cancer screening.

    Science.gov (United States)

    Berchi, Célia; Guittet, Lydia; Bouvier, Véronique; Launoy, Guy

    2010-01-01

    Most industrialized countries, including France, have undertaken to generalize colorectal cancer screening using guaiac fecal occult blood tests (G-FOBT). However, recent researches demonstrate that immunochemical fecal occult blood tests (I-FOBT) are more effective than G-FOBT. Moreover, new generation I-FOBT benefits from a quantitative reading technique allowing the positivity threshold to be chosen, hence offering the best balance between effectiveness and cost. We aimed at comparing the cost and the clinical performance of one round of screening using I-FOBT at different positivity thresholds to those obtained with G-FOBT to determine the optimal cut-off for I-FOBT. Data were derived from an experiment conducted from June 2004 to December 2005 in Calvados (France) where 20,322 inhabitants aged 50-74 years performed both I-FOBT and G-FOBT. Clinical performance was assessed by the number of advanced tumors screened, including large adenomas and cancers. Costs were assessed by the French Social Security Board and included only direct costs. Screening using I-FOBT resulted in better health outcomes and lower costs than screening using G-FOBT for thresholds comprised between 75 and 93 ng/ml. I-FOBT at 55 ng/ml also offers a satisfactory alternative to G-FOBT, because it is 1.8-fold more effective than G-FOBT, without increasing the number of unnecessary colonoscopies, and at an extra cost of 2,519 euros per advanced tumor screened. The use of an automated I-FOBT at 75 ng/ml would guarantee more efficient screening than currently used G-FOBT. Health authorities in industrialized countries should consider the replacement of G-FOBT by an automated I-FOBT test in the near future.

  6. Localization of proteins in paint cross-sections by scanning electrochemical microscopy as an alternative immunochemical detection technique

    Energy Technology Data Exchange (ETDEWEB)

    Sciutto, Giorgia; Prati, Silvia [Microchemistry and Microscopy Art Diagnostic Laboratory, University of Bologna, Via Guaccimanni 42, Ravenna 48121 (Italy); Department of Chemistry “G. Ciamician”, University of Bologna, Via Selmi, Bologna 2 40126 (Italy); Mazzeo, Rocco, E-mail: rocco.mazzeo@unibo.it [Microchemistry and Microscopy Art Diagnostic Laboratory, University of Bologna, Via Guaccimanni 42, Ravenna 48121 (Italy); Department of Chemistry “G. Ciamician”, University of Bologna, Via Selmi, Bologna 2 40126 (Italy); Zangheri, Martina; Roda, Aldo; Bardini, Luca; Valenti, Giovanni; Rapino, Stefania [Department of Chemistry “G. Ciamician”, University of Bologna, Via Selmi, Bologna 2 40126 (Italy); Marcaccio, Massimo, E-mail: massimo.marcaccio@unibo.it [Department of Chemistry “G. Ciamician”, University of Bologna, Via Selmi, Bologna 2 40126 (Italy)

    2014-06-01

    Highlights: • Advanced immuno-electrochemical detection of proteins in paint samples by SECM. • Analysis performed directly on cross-section with high spatial resolution. • Identification of HRP catalytic activity for a selective location of analyte. • Satisfactory results were obtained for aged real samples. • The way forward for an extensive application of SECM in conservation science is shown. - Abstract: The qualitative identification of proteinaceous substances, as well as their location within a complex paint stratigraphy, is one of the most challenging issues in the characterization of painting materials. Nevertheless, information on paint components represent a crucial task for studies concerning both the ancient painting techniques adopted and the state of conservation, being fundamental investigations for the selection of appropriate conservation actions. The present research was aimed at developing a new detection approach for the immunochemical localization of ovalbumin in paint cross-sections based on the use of scanning electrochemical microscopy (SECM). The immunochemical analyses were performed using an anti-ovalbumin primary antibody and a secondary antibody labelled with horseradish peroxidase (HRP). SECM measurements were performed in feedback mode using benzoquinone (BQ)/hydroquinone (H{sub 2}Q) redox couple. In presence of hydrogen peroxide (H{sub 2}O{sub 2}), HRP catalyzes the re-oxidation of H{sub 2}Q to BQ and the increment of BQ concentration in correspondence of the target protein was detected by SECM through the electrochemical reduction of the regenerated BQ at the microelectrode. Indeed, the localization of ovalbumin was possible thanks to a clear discrimination of SECM currents, achieved by the comparison of the measurements recorded before and after H{sub 2}O{sub 2} administration, based on the HRP on/off approach. The method was evaluated both on samples from standard mocks-up and on a historical sample, collected from a

  7. Optical Spectra of Radio Planetary Nebulae in the Small Magellanic Cloud

    Directory of Open Access Journals (Sweden)

    Payne, J. L.

    2008-06-01

    Full Text Available We present preliminary results from spectral observations of four (4 candidate radio sources co-identified with known planetary nebulae (PNe in the Small Magellanic Cloud (SMC. These were made using the Radcliffe 1.9-meter telescope in Sutherland, South Africa. These radio PNe were originally found in Australia Telescope Compact Array (ATCA surveys of the SMC at 1.42 and 2.37~GHz, and were further confirmed by new high resolution ATCA images at 6 and 3 cm (4arcsec/2arcsec. Optical PNe and radio candidates are within 2arcsec and may represent a sub-population of selected radio bright objects. Nebular ionized masses of these objects may be 2.6~$M_odot$ or greater, supporting the existence of PNe progenitor central stars with masses up to 8 $M_odot$.

  8. Optical spectra of radio planetary nebulae in the small Magellanic cloud

    Directory of Open Access Journals (Sweden)

    Payne J.L.

    2008-01-01

    Full Text Available We present preliminary results from spectral observations of four (4 candidate radio sources co-identified with known planetary nebulae (PNe in the Small Magellanic Cloud (SMC. These were made using the Radcliffe 1.9-meter telescope in Sutherland, South Africa. These radio PNe were originally found in Australia Telescope Compact Array (ATCA surveys of the SMC at 1.42 and 2.37 GHz, and were further confirmed by new high resolution ATCA images at 6 and 3 cm (400 /200 . Optical PNe and radio candidates are within 200 and may represent a sub- population of selected radio bright objects. Nebular ionized masses of these objects may be 2.6 Mo or greater, supporting the existence of PNe progenitor central stars with masses up to 8 Mo.

  9. The Effect of Solar Radiation on Radio Signal for Radio Astronomy Purposes

    International Nuclear Information System (INIS)

    Nor Hazmin Sabri; Atiq Wahidah Azlan; Roslan Umar; Roslan Umar; Shahirah Syafa Sulan; Zainol Abidin Ibrahim; Wan Zul Adli Wan Mokhtar

    2015-01-01

    Radio astronomy is a subfields of astronomy which is discovers the celestial objects at radio frequencies. Observation in radio astronomy is conducted using single antenna or array of antennas, known as radio telescope. Other than that, radio astronomy also holds an advantage over other alternatives to optical astronomy due to its capability of observing from the ground level. In this study, the effect of solar radiation that contributes the Radio Frequency Interferences (RFI) is reviewed. The low RFI level is required to set up the radio telescope for radio astronomy observation. The effect of solar radiation on radio signal was investigated by determining the RFI pattern using spectrum analyzer. The solar radiation data was obtained from weather station located at KUSZA Observatory, East Coast Environmental Research Institute (ESERI), UniSZA. We can conclude that the solar radiation factor give the minimum significant effect to radio signal. (author)

  10. Sensitive measurement of endotoxin by radio-rocket immunoelectrophoresis using (/sup 125/I)Staphylococcus aureus protein A

    Energy Technology Data Exchange (ETDEWEB)

    Stevens, P; Alam, S; Young, L S; Chesebro, K [California Univ., Los Angeles (USA). Center for the Health Sciences

    1981-06-16

    Antibody directed against the core glycolipid antigen (CGL) of the mutant Salmonella minnesota Re 595 has been shown to cross-react with endotoxin from bacteria within the group Enterobacteriaceae. Using this cross-reactive CGL antibody the authors have developed a sensitive (250 pg) radio-rocket immunoelectrophoretic technique to measure endotoxin. They used the principles of rocket immunoelectrophoresis and increased the sensitivity by using /sup 125/I-labelled staphylococcal protein A which serves as a sensitive probe to bind to the Fc portion of the IgG complexed with antigen. The rocket-shaped (/sup 125/I)protein A labelled immune complexes were detected by radioautography. The sensitivity is 100-fold greater than conventional Coomassie brilliant blue staining. Measurement of CGL was inhibited by normal human serum. However, the assay had the capacity to quantitate endotoxin in buffer extracts of clinically isolated Escherichia coli, Serratia marcescens, Klebsiella pneumoniae but not Pseudomonas aeruginosa. Analysis of various preparations of CGL obtained from different investigators demonstrated wide variation in their immunoreactivity. Because of the significant cross-reaction to detect various endotoxins this method has the potential to measure endotoxemia and assess the immunochemical quality of various endotoxin preparations. Additionally, the techniques of using (/sup 125/I)protein A has wide applicability for the sensitive measurement of other antigens.

  11. 47 CFR 73.6027 - Class A TV notifications concerning interference to radio astronomy, research and receiving...

    Science.gov (United States)

    2010-10-01

    ... interference to radio astronomy, research and receiving installations. 73.6027 Section 73.6027... radio astronomy, research and receiving installations. An applicant for digital operation of an existing... astronomy, research and receiving installations. [69 FR 69331, Nov. 29, 2004] ...

  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. ULTRA STEEP SPECTRUM RADIO SOURCES IN THE LOCKMAN HOLE: SERVS IDENTIFICATIONS AND REDSHIFT DISTRIBUTION AT THE FAINTEST RADIO FLUXES

    Energy Technology Data Exchange (ETDEWEB)

    Afonso, J.; Bizzocchi, L.; Grossi, M.; Messias, H.; Fernandes, C. A. C. [Observatorio Astronomico de Lisboa, Faculdade de Ciencias, Universidade de Lisboa, Tapada da Ajuda, 1349-018 Lisbon (Portugal); Ibar, E.; Ivison, R. J. [UK Astronomy Technology Centre, Royal Observatory, Edinburgh EH9 3HJ (United Kingdom); Simpson, C. [Astrophysics Research Institute, Liverpool John Moores University, Twelve Quays House, Egerton Wharf, Birkenhead CH41 1LD (United Kingdom); Chapman, S.; Gonzalez-Solares, E. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Jarvis, M. J. [Centre for Astrophysics, Science and Technology Research Institute, University of Hertfordshire, Hatfield, Herts AL10 9AB (United Kingdom); Rottgering, H. [Leiden Observatory, Leiden University, Oort Gebouw, P.O. Box 9513, 2300 RA Leiden (Netherlands); Norris, R. P. [CSIRO Astronomy and Space Science, P.O. Box 76, Epping, NSW 1710 (Australia); Dunlop, J.; Best, P. [SUPA, Institute for Astronomy, University of Edinburgh, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Pforr, J. [Institute of Cosmology and Gravitation, University of Portsmouth, Dennis Sciama Building, Burnaby Road, Portsmouth PO1 3FX (United Kingdom); Vaccari, M. [Department of Astronomy, University of Padova, vicolo Osservatorio 3, 35122 Padova (Italy); Seymour, N. [Mullard Space Science Laboratory, UCL, Holmbury St Mary, Dorking, Surrey RH5 6NT (United Kingdom); Farrah, D. [Astronomy Centre, Department of Physics and Astronomy, University of Sussex, Brighton BN1 9QH (United Kingdom); Huang, J.-S., E-mail: jafonso@oal.ul.pt [Department of Astrophysics, Oxford University, Keble Road, Oxford OX1 3RH (United Kingdom); and others

    2011-12-20

    Ultra steep spectrum (USS) radio sources have been successfully used to select powerful radio sources at high redshifts (z {approx}> 2). Typically restricted to large-sky surveys and relatively bright radio flux densities, it has gradually become possible to extend the USS search to sub-mJy levels, thanks to the recent appearance of sensitive low-frequency radio facilities. Here a first detailed analysis of the nature of the faintest USS sources is presented. By using Giant Metrewave Radio Telescope and Very Large Array radio observations of the Lockman Hole at 610 MHz and 1.4 GHz, a sample of 58 USS sources, with 610 MHz integrated fluxes above 100 {mu}Jy, is assembled. Deep infrared data at 3.6 and 4.5 {mu}m from the Spitzer Extragalactic Representative Volume Survey (SERVS) are used to reliably identify counterparts for 48 (83%) of these sources, showing an average total magnitude of [3.6]{sub AB} = 19.8 mag. Spectroscopic redshifts for 14 USS sources, together with photometric redshift estimates, improved by the use of the deep SERVS data, for a further 19 objects, show redshifts ranging from z = 0.1 to z = 2.8, peaking at z {approx} 0.6 and tailing off at high redshifts. The remaining 25 USS sources, with no redshift estimate, include the faintest [3.6] magnitudes, with 10 sources undetected at 3.6 and 4.5 {mu}m (typically [3.6] {approx}> 22-23 mag from local measurements), which suggests the likely existence of higher redshifts among the sub-mJy USS population. The comparison with the Square Kilometre Array Design Studies Simulated Skies models indicates that Fanaroff-Riley type I radio sources and radio-quiet active galactic nuclei may constitute the bulk of the faintest USS population, and raises the possibility that the high efficiency of the USS technique for the selection of high-redshift sources remains even at the sub-mJy level.

  14. UTag: Long-range Ultra-wideband Passive Radio Frequency Tags

    Energy Technology Data Exchange (ETDEWEB)

    Dowla, F

    2007-03-14

    Long-range, ultra-wideband (UWB), passive radio frequency (RF) tags are key components in Radio Frequency IDentification (RFID) system that will revolutionize inventory control and tracking applications. Unlike conventional, battery-operated (active) RFID tags, LLNL's small UWB tags, called 'UTag', operate at long range (up to 20 meters) in harsh, cluttered environments. Because they are battery-less (that is, passive), they have practically infinite lifetimes without human intervention, and they are lower in cost to manufacture and maintain than active RFID tags. These robust, energy-efficient passive tags are remotely powered by UWB radio signals, which are much more difficult to detect, intercept, and jam than conventional narrowband frequencies. The features of long range, battery-less, and low cost give UTag significant advantage over other existing RFID tags.

  15. Russian Speech in Radio: Norm and Deviation

    Directory of Open Access Journals (Sweden)

    Igor V. Nefedov

    2017-06-01

    Full Text Available National radio, like television, is called upon to bring to the masses not only relevant information, but also a high culture of language. There were always serious demands to oral public speech from the point of view of the correctness and uniformity of the pronunciation. However, today the analysis of the language practice of broadcasting often indicates a discrepancy between the use of linguistic resources in existing literary norms. The author of the article from the end of December 2016 to early April 2017 listened and analyzed from the point of view of language correctness the majority of programs on the radio Komsomolskaya Pravda (KP. In general, recognizing the good speech qualification of the workers of this radio, as well as their «guests» (political scientists, lawyers, historians, etc., one can not but note the presence of a significant number of errors in their speech. The material presented in the article allows us to conclude that at present, broadcasting is losing its position in the field of speech culture. Neglect of the rules of the Russian language on the radio «Komsomolskaya Pravda» negatively affects the image of the Russian language, which is formed in the minds of listeners. The language of radio should strive to become a standard of cleanliness and high culture for the population, since it has the enormous power of mass impact and supports the unity of the cultural and linguistic space.

  16. The 1992 World Administrative Radio Conference: Technology and Policy Implications

    Science.gov (United States)

    1993-05-01

    As the 20th century draws to a close, new radio technologies and services are poised to change the ways we communicate. Radio waves already make possible a wide range of services considered commonplace--AM and FM radio broadcasting, television, cellular telephones, remote garage-door openers, and baby monitors. Advances in radio technology are giving birth to even more new products and services, including pocket-sized telephones that may allow people to make and receive calls anywhere in the world, high-definition televisions (HDTV) with superior quality pictures and sound, and static-free digital radios. The 1992 World Administrative Radio Conference (WARC-92) authorized frequencies for many of these new radio communication services, and granted additional frequencies for many existing services, including international broadcasting, satellite-based mobile communications, and communications in space. The effects of these changes will be felt well into the 21st century as countries around the world develop and deploy new communications systems to serve the needs of consumers, businesses, and governments. For the United States, the decisions made at the conference will critically affect how we develop new radio technologies and applications, how competitive this country will be in radio communications equipment and services, and how effectively the United States can exercise its role as a leader in world radio communication policymaking. This study of the outcomes and implications of WARC-92 was requested by the House Committee on Energy and Commerce and the Senate Committee on Commerce, Science, and Transportation. OTA was asked to evaluate the success of U.S. proposals at the conference, discuss the implications of the decisions made for U.S. technology and policy development, and identify options for improving U.S. participation in future world radio communication conferences.

  17. Merger Activity and Radio Emission Within A2061

    Science.gov (United States)

    Bailey, Avery; Sarazin, Craig L.; Clarke, Tracy E.; Chatzikos, Marios; Hogge, Taylor; Wik, Daniel R.; Rudnick, Lawrence; Farnsworth, Damon; Van Weeren, Reinout J.; Brown, Shea

    2015-01-01

    Abell 2061 is a galaxy cluster located in the Corona Borealis Supercluster that boasts radio and X-ray structures indicative of a merger. A2061 is located at a redshift z = .0784, contains two brightest cluster galaxies, and has another cluster (A2067) about 2.5 Mpc to the NE, falling towards it. Within A2061, there exists an elongated structure of soft X-ray emission extending to the NE of cluster's center (referred to as the 'Plume') along with a hard X-ray shock region (the 'Shock') located just NE of the cluster's center. Previous observations in the radio have indicated the presence of a extended, central radio halo/relic accompanying the cluster's main X-ray emission but with slight NE displacement and further NE extension. Also emitting in the radio, to the SW of A2061, is a radio relic. The X-ray structures of A2061 were previously examined in 2009 by a Chandra observation. Here we present the results of an August 2013 XMM-Newton observation of the cluster. This XMM-Newton observation, imaged by three detectors, covers a greater field of view with a longer exposure (48.6 ks) than the previous Chandra observation. We will present images and spectra of various regions of the cluster. In addition, we will discuss the dynamics of the cluster, the nature of the Plume, Shock and other features, and origin of the central diffuse radio halo/relic and SW radio relic. These X-ray observations will also be compared to a numerical simulation from the Simulation Library of Astrophysics cluster Mergers (SLAM).

  18. Influence of food processing on the immunochemical stability of celery allergens

    International Nuclear Information System (INIS)

    Jankiewicz, A.; Baltes, W.; Bögl, K.W.; Dehne, L.I.; Jamin, A.; Hoffmann, A.; Haustein, D.; Vieths, S.

    1997-01-01

    Celery roots were processed by microwave heating, cooking, drying, γ-irradiation, ultra high pressure treatment and high voltage impulse treatment. The immunochemical stabilities of the three known allergenic structures of celery were tested with sera from patients who were sensitised to celery. In addition, rabbit antisera were used to detect the allergens profilin and Api g I on celery immunoblots. The specificity and reactivity of IgE from the patients' sera were investigated by immunoblotting, by an enzyme allergosorbent test (EAST) and by dose-related IgE inhibition experiments. The results of all three methods agreed closely and indicated high antigenic and allergenic activity in native celery which was reduced by thermal processing. The heat-stability of the known celery allergens decreased in the following order: carbohydrate epitopes > profilin > Api g 1. In contrast, the allergenicity was only mildly reduced by non-thermal processing. The results obtained with human IgE were confirmed by an in vitro mediator-release assay that is based on rat basophil leukemia cells (RBL cells) which were passively sensitised with celery-specific murine IgE. With sera from mice that had been immunised with native celery, the native sample and non-thermal celery preparations elicited the strongest mediator release, whereas a weak response was obtained with samples from heat-processed celery. These results agreed closely with the data obtained in allergic patients whose IgE antibodie

  19. Introduction to solar radio astronomy and radio physics

    International Nuclear Information System (INIS)

    Krueger, A.

    1979-01-01

    A systematic summary is presented of the work done during the last thirty years in the field of solar radio astronomy from the standpoint of general solar physics. Instrumental aspects, observations and theory are covered. A brief introduction is given to the matter consisting of the history of solar radio astronomy and some fundamentals of astronomy and solar physics are outlined. Some topics of the instrumental background of solar radio astronomy and the main results of observations are presented. The elements of a theoretical interpretation of solar radio observations are reported and a synthesis of both observation and theory contributing to a general picture of solar and solar-terrestrial physics is outlined. (C.F./Auth)

  20. Impact of gender on decisions to participate in faecal immunochemical test-based colorectal cancer screening: a qualitative study.

    Science.gov (United States)

    Clarke, Nicholas; Gallagher, Pamela; Kearney, Patricia M; McNamara, Deirdre; Sharp, Linda

    2016-12-01

    Faecal immunochemical tests (FITs) are increasingly being used in population-based colorectal cancer-screening programmes. Uptake of FIT is lower in men than women; however, the reasons for this are not well understood. We aimed to explore gender differences in influences on decisions to participate in FIT screening. This is a qualitative study using in-depth face-to-face interviews of four groups of screening invitees (male and female screening users and male and female screening non-users), purposively sampled from the database of a population-based FIT screening programme. Recruitment continued until saturation was reached. Interviews were audio recorded and transcribed verbatim. Thematic analysis using the framework approach was employed with the theoretical domains framework guiding analysis. Forty-seven screening invitees were interviewed. Six theoretical domains influenced screening uptake: 'environmental context and resources', 'beliefs about capabilities', 'beliefs about consequences', 'emotions', 'social influences' and 'knowledge'. Male non-users were often fatalistic, less knowledgeable and misinformed about cancer and FIT screening compared with other groups. Female non-users expressed negative attitudes, beliefs and emotions towards FIT screening, cancer, social influences and the medical profession and were over-confident about their health. Negative attitudes and emotions to screening dominated non-user decision-making but differed by gender. Opportunities to improve uptake in men and women exist. Greater national discussions on the benefits of FIT screening, and development of screening materials tackling negative attitudes and beliefs while recognising male/female differences, may improve screening uptake. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  1. Impact of cognitive radio on radio astronomy

    NARCIS (Netherlands)

    Bentum, Marinus Jan; 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

  2. Review of Radio Frequency Photonics Basics

    Science.gov (United States)

    2017-09-06

    AFRL-RY-WP-TR-2017-0157 REVIEW OF RADIO FREQUENCY PHOTONICS BASICS Preetpaul S. Devgan RF/EO Subsystems Branch Aerospace Components & Subsystems...Center (DTIC) (http://www.dtic.mil). AFRL-RY-WP-TR-2017-0157 HAS BEEN REVIEWED AND IS APPROVED FOR PUBLICATION IN ACCORDANCE WITH ASSIGNED...including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing

  3. Giant Metrewave Radio Telescope Observations of Head–Tail Radio Galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Sebastian, Biny; Lal, Dharam V.; Rao, A. Pramesh, E-mail: biny@ncra.tifr.res.in [National Center for Radio Astrophysics—Tata Institute of Fundamental Research Post Box 3, Ganeshkhind P.O., Pune 41007 (India)

    2017-10-01

    We present results from a study of seven large known head–tail radio galaxies based on observations using the Giant Metrewave Radio Telescope at 240 and 610 MHz. These observations are used to study the radio morphologies and distribution of the spectral indices across the sources. The overall morphology of the radio tails of these sources is suggestive of random motions of the optical host around the cluster potential. The presence of multiple bends and wiggles in several head–tail sources is possibly due to the precessing radio jets. We find steepening of the spectral index along the radio tails. The prevailing equipartition magnetic field also decreases along the radio tails of these sources. These steepening trends are attributed to the synchrotron aging of plasma toward the ends of the tails. The dynamical ages of these sample sources have been estimated to be ∼10{sup 8} yr, which is a factor of six more than the age estimates from the radiative losses due to synchrotron cooling.

  4. 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.

  5. Software-Defined Radio for Wireless Local-Area Networks

    NARCIS (Netherlands)

    Schiphorst, Roelof

    2004-01-01

    New wireless communications standards do not replace old ones, instead the number of standards keeps on increasing and by now an abundance of standards exists. Moreover there is no reason to assume that this trend will ever stop. Therefore, the software-radio concept is emerging as a potential

  6. Amateur Planetary Radio Data Archived for Science and Education: Radio Jove

    Science.gov (United States)

    Thieman, J.; Cecconi, B.; Sky, J.; Garcia, L. N.; King, T. A.; Higgins, C. A.; Fung, S. F.

    2015-12-01

    The Radio Jove Project is a hands-on educational activity in which students, teachers, and the general public build simple radio telescopes, usually from a kit, to observe single frequency decameter wavelength radio emissions from Jupiter, the Sun, the galaxy, and the Earth usually with simple dipole antennas. Some of the amateur observers have upgraded their receivers to spectrographs and their antennas have become more sophisticated as well. The data records compare favorably to more sophisticated professional radio telescopes such as the Long Wavelength Array (LWA) and the Nancay Decametric Array. Since these data are often carefully calibrated and recorded around the clock in widely scattered locations they represent a valuable database useful not only to amateur radio astronomers but to the professional science community as well. Some interesting phenomena have been noted in the data that are of interest to the professionals familiar with such records. The continuous monitoring of radio emissions from Jupiter could serve as useful "ground truth" data during the coming Juno mission's radio observations of Jupiter. Radio Jove has long maintained an archive for thousands of Radio Jove observations, but the database was intended for use by the Radio Jove participants only. Now, increased scientific interest in the use of these data has resulted in several proposals to translate the data into a science community data format standard and store the data in professional archives. Progress is being made in translating Radio Jove data to the Common Data Format (CDF) and also in generating new observations in that format as well. Metadata describing the Radio Jove data would follow the Space Physics Archive Search and Extract (SPASE) standard. The proposed archive to be used for long term preservation would be the Planetary Data System (PDS). Data sharing would be achieved through the PDS and the Paris Astronomical Data Centre (PADC) and the Virtual Wave Observatory (VWO

  7. La radio digital

    Directory of Open Access Journals (Sweden)

    Carlos Eduardo Cortés S.

    2015-01-01

    Full Text Available La radio digital es un producto de la llamada convergencia digital. Las nuevas tecnologías interconectadas permiten la aparición de nuevos modos de audiencia y la implementación de herramientas versátiles. Habla del problema de los estándares, de la radio satelital, la radio digital terrestre, las radios internacionales, la interactividad.

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

    NARCIS (Netherlands)

    Haartsen, J.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

  9. Determining Thunderstorm Electric Fields using Radio Emission from Cosmic-Ray Air Showers

    Science.gov (United States)

    Hare, B.; Scholten, O.; Trinh, G. T. N.; Ebert, U.; Rutjes, C.

    2017-12-01

    We report on a novel non-intrusive way to investigate electric fields in thunderclouds.Energetic cosmic rays penetrating the atmosphere create a particle avalanche called an extensive air shower. The front of the shower is a plasma cloud that contains 10^6 or more free electrons and positrons moving towards the Earth's surface at the speed of light. The electric fields that exists in thunderclouds induces electric currents in the plasma cloud that emit radio waves. The radio footprint for intensity, linear and circular polarization thus contains the finger print of the atmospheric electric fields along the path of the air shower.Here we report on the analysis of many cosmic-ray radio footprints as have been measured at LOFAR, a dense array of simple radio antennas (several thousands of dual-polarized antennas) primarily developed for radio-astronomy observations. We show that this method can be used to determine the charge structure in thunderclouds and discuss the accuracy of the method. We have observed seasonal dependencies.

  10. Are Hemorrhoids Associated with False-Positive Fecal Immunochemical Test Results?

    Science.gov (United States)

    Kim, Nam Hee; Park, Jung Ho; Park, Dong Il; Sohn, Chong Il; Choi, Kyuyong; Jung, Yoon Suk

    2017-01-01

    False-positive (FP) results of fecal immunochemical tests (FITs) conducted in colorectal cancer (CRC) screening could lead to performing unnecessary colonoscopies. Hemorrhoids are a possible cause of FP FIT results; however, studies on this topic are extremely rare. We investigated whether hemorrhoids are associated with FP FIT results. A retrospective study was conducted at a university hospital in Korea from June 2013 to May 2015. Of the 34547 individuals who underwent FITs, 3946 aged ≥50 years who underwent colonoscopies were analyzed. Logistic regression analysis was performed to determine factors associated with FP FIT results. Among 3946 participants, 704 (17.8%) showed positive FIT results and 1303 (33.0%) had hemorrhoids. Of the 704 participants with positive FIT results, 165 had advanced colorectal neoplasia (ACRN) and 539 had no ACRN (FP results). Of the 1303 participants with hemorrhoids, 291 showed FP results, of whom 81 showed FP results because of hemorrhoids only. Participants with hemorrhoids had a higher rate of FP results than those without hemorrhoids (291/1176, 24.7% vs. 248/2361, 10.5%; phemorrhoids as the only abnormality had a higher rate of FP results than those experiencing no such abnormalities (81/531, 15.3% vs. 38/1173, 3.2%; phemorrhoids was identified as an independent predictor of FP results (adjusted odds ratio, 2.76; 95% confidence interval, 2.24-3.40; pHemorrhoids are significantly associated with FP FIT results. Their presence seemed to be a non-negligible contributor of FP results in FIT-based CRC screening programs.

  11. 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...

  12. The radio spectral energy distribution of infrared-faint radio sources

    Science.gov (United States)

    Herzog, A.; Norris, R. P.; 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.; Kapińska, 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.; Udaya Shankar, N.; 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.; Bannister, K. W.; Chippendale, A. P.; Harvey-Smith, L.; Heywood, I.; Indermuehle, B.; Popping, A.; Sault, R. J.; Whiting, M. T.

    2016-10-01

    Context. 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. Aims: Because of their optical and infrared faintness, it is very challenging to study IFRS at these wavelengths. However, IFRS are relatively bright in the radio regime with 1.4 GHz flux densities of a few to a few tens of mJy. Therefore, the radio regime is the most promising wavelength regime in which to constrain their nature. 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. Methods: 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-far-infrared SED of this source. Results: We find IFRS usually follow single power laws down to observed frequencies of around 150 MHz. Mostly, the radio SEDs are steep (α IFRS show statistically significantly steeper radio SEDs than the broader RL AGN population. Our analysis reveals that the fractions of GPS and CSS sources in the population of IFRS are consistent with the fractions in the broader RL AGN population. We find that at least % of IFRS contain young AGN, although the fraction might be significantly higher as suggested by the steep SEDs and the compact morphology of IFRS. The detailed multi

  13. The radio universe

    International Nuclear Information System (INIS)

    Worvill, R.

    1977-01-01

    Elementary description of the development of radioastronomy, radio waves from the sun and planets, the use of radio telescopes and the detection of nebulae, supernova, radio galaxies and quasars is presented. A brief glossary of terms is included. (UK)

  14. DISCLOSING THE RADIO LOUDNESS DISTRIBUTION DICHOTOMY IN QUASARS: AN UNBIASED MONTE CARLO APPROACH APPLIED TO THE SDSS-FIRST QUASAR SAMPLE

    Energy Technology Data Exchange (ETDEWEB)

    Balokovic, M. [Department of Astronomy, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Smolcic, V. [Argelander-Institut fuer Astronomie, Auf dem Hugel 71, D-53121 Bonn (Germany); Ivezic, Z. [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States); Zamorani, G. [INAF-Osservatorio Astronomico di Bologna, via Ranzani 1, I-40127 Bologna (Italy); Schinnerer, E. [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, D-69117 Heidelberg (Germany); Kelly, B. C. [Department of Physics, Broida Hall, University of California, Santa Barbara, CA 93106 (United States)

    2012-11-01

    We investigate the dichotomy in the radio loudness distribution of quasars by modeling their radio emission and various selection effects using a Monte Carlo approach. The existence of two physically distinct quasar populations, the radio-loud and radio-quiet quasars, is controversial and over the last decade a bimodal distribution of radio loudness of quasars has been both affirmed and disputed. We model the quasar radio luminosity distribution with simple unimodal and bimodal distribution functions. The resulting simulated samples are compared to a fiducial sample of 8300 quasars drawn from the SDSS DR7 Quasar Catalog and combined with radio observations from the FIRST survey. Our results indicate that the SDSS-FIRST sample is best described by a radio loudness distribution which consists of two components, with (12 {+-} 1)% of sources in the radio-loud component. On the other hand, the evidence for a local minimum in the loudness distribution (bimodality) is not strong and we find that previous claims for its existence were probably affected by the incompleteness of the FIRST survey close to its faint limit. We also investigate the redshift and luminosity dependence of the radio loudness distribution and find tentative evidence that at high redshift radio-loud quasars were rarer, on average louder, and exhibited a smaller range in radio loudness. In agreement with other recent work, we conclude that the SDSS-FIRST sample strongly suggests that the radio loudness distribution of quasars is not a universal function, and that more complex models than presented here are needed to fully explain available observations.

  15. DISCLOSING THE RADIO LOUDNESS DISTRIBUTION DICHOTOMY IN QUASARS: AN UNBIASED MONTE CARLO APPROACH APPLIED TO THE SDSS-FIRST QUASAR SAMPLE

    International Nuclear Information System (INIS)

    Baloković, M.; Smolčić, V.; Ivezić, Ž.; Zamorani, G.; Schinnerer, E.; Kelly, B. C.

    2012-01-01

    We investigate the dichotomy in the radio loudness distribution of quasars by modeling their radio emission and various selection effects using a Monte Carlo approach. The existence of two physically distinct quasar populations, the radio-loud and radio-quiet quasars, is controversial and over the last decade a bimodal distribution of radio loudness of quasars has been both affirmed and disputed. We model the quasar radio luminosity distribution with simple unimodal and bimodal distribution functions. The resulting simulated samples are compared to a fiducial sample of 8300 quasars drawn from the SDSS DR7 Quasar Catalog and combined with radio observations from the FIRST survey. Our results indicate that the SDSS-FIRST sample is best described by a radio loudness distribution which consists of two components, with (12 ± 1)% of sources in the radio-loud component. On the other hand, the evidence for a local minimum in the loudness distribution (bimodality) is not strong and we find that previous claims for its existence were probably affected by the incompleteness of the FIRST survey close to its faint limit. We also investigate the redshift and luminosity dependence of the radio loudness distribution and find tentative evidence that at high redshift radio-loud quasars were rarer, on average louder, and exhibited a smaller range in radio loudness. In agreement with other recent work, we conclude that the SDSS-FIRST sample strongly suggests that the radio loudness distribution of quasars is not a universal function, and that more complex models than presented here are needed to fully explain available observations.

  16. 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.

  17. Radio Frequency Interference: The Study of Rain Effect on Radio Signal Attenuation

    International Nuclear Information System (INIS)

    Roslan Umar; Roslan Umar; Shahirah Syafa Sulan; Atiq Wahidah Azlan; Zainol Abidin Ibrahim

    2015-01-01

    The intensity of radio waves received by radio telescopes is always not subject to human control. In the millimetre band, the propagation of the electromagnetic waves is severely affected by rain rate, dust particle size and drop size in the terms of attenuation, noise and depolarization. At the frequency above 10 GHz, the absorption and scattering by rain cause a reduction in the transmitted signal amplitude which will lead to the reducing of the availability, reliability and performance on the communications link. In this study, the rain effect on radio signal has been investigated. Spectrum analyzer and weather stations were used to obtain the RFI level and rain rate data respectively. The radio frequency interference (RFI) pattern due to rain factor was determined. This will benefit radio astronomer in managing sites for radio observation for radio astronomy purposes. (author)

  18. Mean and Extreme Radio Properties of Quasars and the Origin of Radio Emission

    Science.gov (United States)

    Richards, Gordon T.; Kratzer, R.

    2014-01-01

    We explore the evolution of the fraction of radio loud quasars and the mean radio properties of quasars. Although any quasar has only a ~10% chance of being radio loud and the average quasar has a radio luminosity of ~4x10^30 ergs/s/Hz, these properties are strong functions of not only luminosity, redshift, black hole mass, and accretion rate, but also the strength of the accretion disk wind (as characterized by CIV emission line properties). Quasars with higher optical luminosity and/or lower redshift have a higher than average probability of being radio loud, but their median radio luminosity (relative to optical) is much lower than average. We find that, while radio properties of quasars generally cannot be predicted from their optical properties, objects where one expects a strong radiation line driven wind (based on emission line features) have virtually no chance of being radio loud. The redder quasars are in the optical, the more radio flux (relative to optical) they have; this trend holds even for quasars that are not expected to be significantly dust reddened/extincted in the optical. Finally, we consider the radio properties of quasars in the framework of models which describe the radio loud extrema as being due to particularly high spin resulting from second generation mergers and in the context of star formation at lower levels of radio flux. This work was supported by NSF AAG grant 1108798.

  19. Neutrino Bursts from Fanaroff-Riley I Radio Galaxies

    CERN Document Server

    Anchordoqui, Luis A.; Halzen, Francis; Weiler, Thomas J.; Anchordoqui, Luis A.; Goldberg, Haim; Halzen, Francis; Weiler, Thomas J.

    2004-01-01

    On the basis of existing observations (at the 4.5 \\sigma level) of TeV gamma-ray outbursts from the Fanaroff-Riley I (FRI) radio galaxy Centaurus A, we estimate the accompanying neutrino flux in a scenario where both photons and neutrinos emerge from pion decay. We find a neutrino flux on Earth dF_{\

  20. Novel artificial stool material for external quality assurance (EQA) on a fecal immunochemical test for hemoglobin (FIT): The confirmed utility of stable hemoglobin and an internal standard material.

    Science.gov (United States)

    Yasui, Ryota; Yamada, Miyu; Takehara, Shizuka; Sakurabayashi, Ikunosuke; Watanabe, Katsunori

    2018-04-16

    The fecal immunochemical test for hemoglobin (FIT), which detects lower gastrointestinal bleeding, is widely accepted for population-based colorectal cancer (CRC) screening programs. However, the FIT screening process has not been standardized yet, and standardizing the pre-analytical phase and establishing an external quality assurance (EQA) program compliant with ISO requirements is urgently needed. Although there have been various attempts to establish EQA materials suitable for FIT, no materials have yet been reported to have sufficient uniformity and acceptable immunochemical stability of hemoglobin (Hb). The Health Care Technology Foundation (HECTEF; Tokyo Japan) is now developing a ready-to-use artificial stool containing Hb and an internal standard, glycerol. Accordingly, we verified the adaptability and efficacy of this material for the evaluation of the specimen collection phase of FIT. This material uniformly contained both Hb and glycerol. The glycerol allowed us to estimate the weight of the collected artificial stool and to correct the Hb concentration with the estimated weight. Furthermore, the stability of both Hb and glycerol were confirmed to be sufficient for an EQA material under appropriate storage, in-use, repeated freeze-thaw, and heated conditions. These in-house performance characteristics suggest that HECTEF artificial stool is acceptable as an EQA material for FIT. Copyright © 2018 Elsevier B.V. All rights reserved.

  1. Graphene radio frequency receiver integrated circuit.

    Science.gov (United States)

    Han, Shu-Jen; Garcia, Alberto Valdes; Oida, Satoshi; Jenkins, Keith A; Haensch, Wilfried

    2014-01-01

    Graphene has attracted much interest as a future channel material in radio frequency electronics because of its superior electrical properties. Fabrication of a graphene integrated circuit without significantly degrading transistor performance has proven to be challenging, posing one of the major bottlenecks to compete with existing technologies. Here we present a fabrication method fully preserving graphene transistor quality, demonstrated with the implementation of a high-performance three-stage graphene integrated circuit. The circuit operates as a radio frequency receiver performing signal amplification, filtering and downconversion mixing. All circuit components are integrated into 0.6 mm(2) area and fabricated on 200 mm silicon wafers, showing the unprecedented graphene circuit complexity and silicon complementary metal-oxide-semiconductor process compatibility. The demonstrated circuit performance allow us to use graphene integrated circuit to perform practical wireless communication functions, receiving and restoring digital text transmitted on a 4.3-GHz carrier signal.

  2. Immunochemical analysis of Micrococcus lysodeikticus (luteus) F1-ATPase and its subunits.

    Science.gov (United States)

    Urban, C; Salton, M R

    1983-08-31

    The F1-ATPase from Micrococcus lysodeikticus has been purified to 95% protein homogeneity in this laboratory and as all other bacterial F1S, possesses five distinct subunits with molecular weights ranging from 60 000 to 10 000 (Huberman, M. and Salton, M.R.J. (1979) Biochim. Biophys. Acta 547, 230-240). In this communication, we demonstrate the immunochemical reactivities of antibodies to native and SDS-dissociated subunits with the native and dissociated F1-ATPase and show that: (1) the antibodies generated to the native or SDS-dissociated subunits react with the native molecule; (2) all of the subunits comprising the F1 are antigenically unique as determined by crossed immunoelectrophoresis and the Ouchterlony double-diffusion techniques; (3) antibodies to the SDS-denatured individual delta- and epsilon-subunits can be used to destabilize the interaction of these specific subunits with the rest of the native F1; and (4) all subunit antibodies as well as anti-native F1 were found to inhibit ATPase activity to varying degrees, the strongest inhibition being seen with antibodies to the total F1 and anti-alpha- and anti-beta-subunit antibodies. The interaction of specific subunit antibodies may provide a new and novel way to study further and characterize the catalytic portions of F1-ATPases and in general may offer an additional method for the examination of multimeric proteins.

  3. Constraining the CMB optical depth through the dispersion measure of cosmological radio transients

    International Nuclear Information System (INIS)

    Fialkov, A.; Loeb, A.

    2016-01-01

    The dispersion measure of extragalactic radio transients can be used to measure the column density of free electrons in the intergalactic medium. The same electrons also scatter the Cosmic Microwave Background (CMB) photons, affecting precision measurements of cosmological parameters. We explore the connection between the dispersion measure of radio transients existing during the Epoch of Reionization (EoR) and the total optical depth for the CMB showing that the existence of such transients would provide a new sensitive probe of the CMB optical depth. As an example, we consider the population of FRBs. Assuming they exist during the EoR, we show that: (i) such sources can probe the reionization history by measuring the optical depth to sub-percent accuracy, and (ii) they can be detected with high significance by an instrument such as the Square Kilometer Array.

  4. Constraining the CMB optical depth through the dispersion measure of cosmological radio transients

    Energy Technology Data Exchange (ETDEWEB)

    Fialkov, A.; Loeb, A., E-mail: anastasia.fialkov@cfa.harvard.edu, E-mail: aloeb@cfa.harvard.edu [Institute for Teory and Computation, Harvard University, 60 Garden Street, MS-51, Cambridge, MA, 02138 (United States)

    2016-05-01

    The dispersion measure of extragalactic radio transients can be used to measure the column density of free electrons in the intergalactic medium. The same electrons also scatter the Cosmic Microwave Background (CMB) photons, affecting precision measurements of cosmological parameters. We explore the connection between the dispersion measure of radio transients existing during the Epoch of Reionization (EoR) and the total optical depth for the CMB showing that the existence of such transients would provide a new sensitive probe of the CMB optical depth. As an example, we consider the population of FRBs. Assuming they exist during the EoR, we show that: (i) such sources can probe the reionization history by measuring the optical depth to sub-percent accuracy, and (ii) they can be detected with high significance by an instrument such as the Square Kilometer Array.

  5. The Models for Radio Emission from Pulsars – The Outstanding issues

    Indian Academy of Sciences (India)

    tribpo

    in section 4, where existing models for pulsar radio emission are also reviewed. ... pair plasma flowing outward along open magnetic field lines from the polar caps ..... A reactive instability involves an intrinsically growing, phase-coherent wave.

  6. Faraday rotation in the M87 radio/X-ray halo

    Science.gov (United States)

    Dennison, B.

    1980-01-01

    Comparison of polarization maps at various wavelengths demonstrates the existence of a large Faraday rotation uniform over the radio core of M87. Much of this rotation must be external to the core, lest it appear completely depolarized when the rotation is about 90 degrees. The Faraday rotation is shown to occur primarily in the surrounding radio/X-ray halo. Using the electron density inferred from X-ray observations, the magnetic field in the halo is found to be 2.5 microgauss. The deduced magnetic field strength permits an evaluation of the importance of Compton scattering of 3 K background photons by relativistic electrons in the radio halo. The emergent Compton-scattered spectrum is calculated, and its contribution to the observed X-ray flux is small, probably about a percent or so, while the rest is due to thermal bremsstrahlung.

  7. A radio and optical study of Molonglo radio sources

    Science.gov (United States)

    Ishwara-Chandra, C. H.; Saikia, D. J.; McCarthy, P. J.; van Breugel, W. J. M.

    2001-05-01

    We present multi-wavelength radio observations with the Very Large Array, and narrow- and broad-band optical observations with the 2.5-m telescope at the Las Campanas Observatory, of a well-defined sample of high-luminosity Fanaroff-Riley class II radio galaxies and quasars, selected from the Molonglo Reference Catalogue 1-Jy sample. These observations were carried out as part of a programme to investigate the effects of orientation and environment on some of the observed properties of these sources. We examine the dependence of the Liu-Pooley relationship, which shows that radio lobes with flatter radio spectra are less depolarized, on size, identification and redshift, and show that it is significantly stronger for smaller sources, with the strength of the relationship being similar for both radio galaxies and quasars. In addition to Doppler effects, there appear to be intrinsic differences between the lobes on opposite sides. We discuss the asymmetry in brightness and location of the hotspots, and present estimates of the ages and velocities from matched-resolution observations in the L and C bands. Narrow- and broad-band optical images of some of these sources were made to study their environments and correlate with the symmetry parameters. An extended emission-line region is seen in a quasar, and in four of the objects possible companion galaxies are seen close to the radio axis.

  8. Co-existing hidden attractors in a radio-physical oscillator system

    DEFF Research Database (Denmark)

    Kuznetsov, A. P.; Kuznetsov, S. P.; Mosekilde, Erik

    2015-01-01

    The term `hidden attractor' relates to a stable periodic, quasiperiodic or chaotic state whose basin of attraction does not overlap with the neighborhood of an unstable equilibrium point. Considering a three-dimensional oscillator system that does not allow for the existence of an equilibrium point...... frequency, describe the bifurcations through which hidden attractors of different type arise and disappear, and illustrate the form of the basins of attraction....

  9. Traceability of sulfonamide antibiotic treatment by immunochemical analysis of farm animal hair samples.

    Science.gov (United States)

    Adrian, Javier; Gratacós-Cubarsí, Marta; Sánchez-Baeza, Francisco; Garcia Regueiro, Jose-Antonio; Castellari, Massimo; Marco, M-Pilar

    2009-10-01

    The use of hair to trace use of unauthorized substances, therapeutic agents, or their misuse is becoming very attractive since residues can be detected for a long time after treatment. For this purpose, an indirect enzyme-linked immunosorbent assay (ELISA) has been evaluated for its capability to trace sulfonamide antibiotic treatment by analyzing cattle and pig hair samples. Pigmented and nonpigmented hair samples from control and sulfamethazine (SMZ)-treated pigs and calves were collected, extracted under different alkaline conditions, and analyzed by ELISA after just diluting the extracts with the assay buffer. Data analysis following the European recommendations for screening methods demonstrates that the ELISA can detect SMZ in hair samples with a limit of detection (90% of the zero dose (IC(90))) between 30 and 75 ng g(-1). The same samples have been analyzed by HPLC after a dual solid-phase extraction. The ELISA results matched very well those obtained by the chromatographic method, demonstrating that the immunochemical method can be used as a screening tool to trace animal treatments. Between the benefits of this method are the possibility to directly analyze hair extracts with sufficient detectability and its high-throughput capability. Preliminary validation data are reported using an experimental approach inspired on the Commission Decision 2002/657/EC criteria for screening methods.

  10. Evolution of extra-galactic nebulae and the origin of metagalactic radio noise

    International Nuclear Information System (INIS)

    Bruce, C.E.R.

    1975-01-01

    It is pointed out that the discovery of the 'jet' in the radio source NGC 4486 fulfils a prediction made many years ago that such 'jets' would exist in some globular or elliptical nebulae. They are the channels of electrical discharges on a nebular scale then postulated, which will last for about 10 million years. It is emphasized that the discharge hypothesis would account for - 1. the existence of irregular nebulae; 2. the 'cataclysmic action' which Hubble regarded as required to account for the transition from nebulae of Type E to Type Sa; 3. the fact that the arms of spiral nebulae are never seen in process of formation; 4. the gathering of the matter towards the discharge channels by magnetic pinch effect; 5. the frequent occurrence of two diametrically opposed major arms; 6. the origin of radio waves throughout an extensive volume of space surrounding the 'jet' or discharge channel in NGC 4486; 7. the effect of one extra galactic nebula, NGC 3187, on another, NGC 3190; 8. the existence of diffuse patches of luminosity, 'emission nebulae', in the spiral arms of our own galaxy and in those of the 'Andromeda Nebula'. On the discharge theory about one per cent of all nebulae will be passing through the discharge phase at any one time, i.e., the number required to account for the observed intensity of metagalactic radio noise. (author)

  11. Radio-capacity of ecosystems

    International Nuclear Information System (INIS)

    Kultakhmedov, Yu.; Kultakhmedova-Vyshnyakova, V.

    1997-01-01

    This paper consider a universal approach to ecosystems of different types, based on representation of their radio-capacity. The concept of ecosystem includes reproduction of components (bio-productivity) and conditions such as maintaining of environment quality. Radio-capacity in the case of radionuclide pollution appears in accumulation and redistribution of radionuclides in the ecosystem. As a result the radionuclides are redistributed and buried in soil or lake bottom sediments. Estimation models for the radio-capacity of water and terrestrial ecosystems are represented. The calculations of the radio-capacity factor of water ecosystems are performed, and the high radio-capacity of a freshwater reservoir (F=0.6-0.8) and extremely high radio-capacity of a reservoir cascade (F c =0.99) is shown material from the Dnieper's cascade reservoirs. The methods of radio-capacity estimation of agroecosystems, wood and marine ecosystems are developed. (authors)

  12. 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 ) .............................................................................. 15 1.12 The Radio Amateurs’ Examination .......................................................................... 15 1.13 Restrictions on the Use of an Amateur Radio Station .............................................. 16 Chapter 2: Operating... ............................................................................................. 116 14.1 Theory of Operation ............................................................................................... 116 14.2 Turns Ratio...

  13. 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

  14. Radio Frequency Interference Site Survey for Thai Radio Telescopes

    Science.gov (United States)

    Jaroenjittichai, P.; Punyawarin, S.; Singwong, D.; Somboonpon, P.; Prasert, N.; Bandudej, K.; Kempet, P.; Leckngam, A.; Poshyachinda, S.; Soonthornthum, B.; Kramer, B.

    2017-09-01

    Radio astronomical observations have increasingly been threaten by the march of today telecommunication and wireless technology. Performance of radio telescopes lies within the fact that astronomical sources are extremely weak. National Astronomy Research Institute of Thailand (NARIT) has initiated a 5-year project, known as the Radio Astronomy Network and Geodesy for Development (RANGD), which includes the establishment of 40-meter and 13-meter radio telescopes. Possible locations have been narrowed down to three candidates, situated in the Northern part of Thailand, where the atmosphere is sufficiently dry and suitable for 22 and 43 GHz observations. The Radio Frequency Interference (RFI) measurements were carried out with a DC spectrum analyzer and directional antennas at 1.5 meter above ground, from 20 MHz to 6 GHz with full azimuth coverage. The data from a 3-minute pointing were recorded for both horizontal and vertical polarizations, in maxhold and average modes. The results, for which we used to make preliminary site selection, show signals from typical broadcast and telecommunication services and aeronautics applications. The signal intensity varies accordingly to the presence of nearby population and topography of the region.

  15. Stellar populations in distant radio galaxies

    International Nuclear Information System (INIS)

    Lilly, S.J.; Longair, M.S.

    1984-01-01

    A homogeneous data set of infrared observations of 83 3CR galaxies with redshifts 0< z<1.6, selected from a statistically complete sample of 90 radio sources, is used to study the colours and magnitudes of these galaxies as a function of their redshifts. New infrared observations are presented for 66 radio galaxies, in addition to new optical results obtained from a re-analysis of existing CCD images. It is shown that the infrared colours do not deviate from the predicted relations with redshift for a standard giant elliptical galaxy spectrum. The optical to infrared colours, however, show substantial deviations at high redshift. No galaxies have been found that are significantly redder than a passively evolving galaxy, and there is a significant scatter of colours bluewards from this model. The excess of ultraviolet light responsible for these colours is not concentrated at the nucleus, and is interpreted as resulting from bursts of star formation, throughout the galaxy. (author)

  16. Long-term radio and X-ray evolution of the tidal disruption event ASASSN-14li

    Science.gov (United States)

    Bright, J. S.; Fender, R. P.; Motta, S. E.; Mooley, K.; Perrott, Y. C.; van Velzen, S.; Carey, S.; Hickish, J.; Razavi-Ghods, N.; Titterington, D.; Scott, P.; Grainge, K.; Scaife, A.; Cantwell, T.; Rumsey, C.

    2018-04-01

    We report on late time radio and X-ray observations of the tidal disruption event candidate ASASSN-14li, covering the first 1000 d of the decay phase. For the first ˜200 d the radio and X-ray emission fade in concert. This phase is better fitted by an exponential decay at X-ray wavelengths, while the radio emission is well described by either an exponential or the canonical t-5/3 decay assumed for tidal disruption events. The correlation between radio and X-ray emission during this period can be fitted as L_R∝ L_X^{1.9± 0.2}. After 400 d the radio emission at 15.5 GHz has reached a plateau level of 244 ± 8 μJy which it maintains for at least the next 600 d, while the X-ray emission continues to fade exponentially. This steady level of radio emission is likely due to relic radio lobes from the weak AGN-like activity implied by historical radio observations. We note that while most existing models are based upon the evolution of ejecta which are decoupled from the central black hole, the radio-X-ray correlation during the declining phase is also consistent with core-jet emission coupled to a radiatively efficient accretion flow.

  17. Stellar Dynamics and Star Formation Histories of z ∼ 1 Radio-loud Galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Barišić, Ivana; Van der Wel, Arjen; Chauké, Priscilla; Van Houdt, Josha; Straatman, Caroline [Max-Planck Institut für Astronomie, Königstuhl 17, D-69117, Heidelberg (Germany); Bezanson, Rachel [Department of Astrophysics, Princeton University, Princeton, NJ 08544 (United States); Pacifici, Camilla [Astrophysics Science Division, Goddard Space Flight Center, Code 665, Greenbelt, MD 20771 (United States); Noeske, Kai [experimenta gGmbH, Kranenstraße 14, 74072 Heilbronn (Germany); Muñoz-Mateos, Juan C. [European Southern Observatory, Alonso de Córdova 3107, Casilla 19001, Vitacura, Santiago (Chile); Franx, Marijn; Labbé, Ivo; Maseda, Michael V.; Sobral, David [Leiden Observatory, Leiden University, P.O. Box 9513, NL-2300 AA Leiden (Netherlands); Smolčić, Vernesa [Department of Physics, Faculty of Science, University of Zagreb, Bijenicka cesta 32, 10000 Zagreb (Croatia); Bell, Eric F. [Department of Astronomy, University of Michigan, 1085 S. University Avenue, Ann Arbor, MI 48109 (United States); Brammer, Gabriel [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Calhau, João [Department of Physics, Lancaster University, Lancaster LA1 4 YB (United Kingdom); Van Dokkum, Pieter G. [Department of Astronomy, Yale University, New Haven, CT 06511 (United States); Gallazzi, Anna [INAF-Osservatorio Astrofsico di Arcetri, Largo Enrico Fermi 5, I-50125 Firenze (Italy); Muzzin, Adam, E-mail: barisic@mpia.de [Department of Physics and Astronomy, York University, 4700 Keele Street, Toronto, Ontario, ON MJ3 1P3 (Canada); and others

    2017-09-20

    We investigate the stellar kinematics and stellar populations of 58 radio-loud galaxies of intermediate luminosities ( L {sub 3} {sub GHz} > 10{sup 23} W Hz{sup −1}) at 0.6 < z < 1. This sample is constructed by cross-matching galaxies from the deep VLT/VIMOS LEGA-C spectroscopic survey with the VLA 3 GHz data set. The LEGA-C continuum spectra reveal for the first time stellar velocity dispersions and age indicators of z ∼ 1 radio galaxies. We find that z ∼ 1 radio-loud active galactic nucleus (AGN) occur exclusively in predominantly old galaxies with high velocity dispersions: σ {sub *} > 175 km s{sup −1}, corresponding to black hole masses in excess of 10{sup 8} M {sub ⊙}. Furthermore, we confirm that at a fixed stellar mass the fraction of radio-loud AGN at z ∼ 1 is five to 10 times higher than in the local universe, suggesting that quiescent, massive galaxies at z ∼ 1 switch on as radio AGN on average once every Gyr. Our results strengthen the existing evidence for a link between high black hole masses, radio loudness, and quiescence at z ∼ 1.

  18. Survival of radio-marked mallard ducklings in northeastern California

    Science.gov (United States)

    Mauser, D.M.; Jarvis, R.L.; Gilmer, D.S.

    1994-01-01

    Estimates of duckling survival are necessary to accurately assess recruitment of mallards (Anas platyrhynchos), yet few reliable estimates exist. During 1988-90, we estimated survival rates for 127 radio-marked mallard ducklings from 64 broods on Lower Klamath National Wildlife Refuge, California. In 1988, we restricted the survival estimate to the first 10 days post-hatch (S = 0.18, SE = 0.07). Survival from hatching to 50 days was 0.37 (SE = 0.09) in 1989 and 0.34 (SE = 0.07) in 1990. Total brood loss differed among years (P < 0.05); 81.2% in 1988 (n = 16), 36.8% in 1989 (n = 19), and 37.5% in 1990 (n = 24). Ninety-three percent of mortality occurred during the first 10 days of life. We detected no differences in the proportion of radio-marked ducklings fledged from early-hatched versus late-hatched nests (P = 0.74). During 1989-90, 16 females appeared to lose their entire brood; however, 3 radio-marked ducklings from 2 of these broods were fledged by other brood hens. Of 29 radio-marked ducklings that reached 44 days of life, 6 (20.7%) joined other broods. Habitat enhancement is the key to improving duckling survival because the large number of predator species that consume ducklings makes predator control difficult.

  19. Design & Test of Radio Communication and Control System for Aquaculture

    Directory of Open Access Journals (Sweden)

    Fengrong Jia

    2013-05-01

    Full Text Available Aiming at low automation degree and backward aquatic product management of current aquaculture in China, this paper designed a set of radio communication and control system which consists of 3 parts of information collection module, control module and radio communication module. This system both realizes wireless monitoring of quality parameters of water for aquaculture and realizes wireless control of water level and dissolved oxygen value through radio communication. Test results show that data transfer is more accurate and reliable after adding customized protocol and answer signals in radio communication. The highest error and missing rate within 1000 m is 0.36, the lowest error and missing rate is 0.05 and the longest response time is 49 ms. The dissolved oxygen value detection system designed in this paper is close to the testing value of existing dissolved oxygen value transmitter DO6309. With wireless data transfer mode, it has higher practicality. The wireless control of dissolved oxygen value and water level can be controlled within the appropriate range with stable and precise control. The study results can provide intelligent aquaculture model with simple operation and precise control for enormous aquatic breeders

  20. The History and Evolution of Young and Distant Radio Sources

    Science.gov (United States)

    Collier, Jordan

    We study two classes of object to gain a better understanding of the evolution of Active Galactic Nuclei (AGN): Infrared-Faint Radio Sources (IFRSs) and Gigahertz Peaked Spectrum (GPS) / Compact Steep Spectrum (CSS) sources. IFRSs are a recently discovered rare class of object, which were found to be strong in the radio but undetectable in extremely sensitive infrared observations from the Spitzer Space Telescope, even in stacked images with sigma 3. Therefore, IFRSs may significantly increase the number of known high-redshift galaxies. However, their non-detections in the optical and infrared prevented confirmation of their nature. Previous studies of IFRSs focused on very sensitive observations of a few small regions of the sky, and the largest sample consisted of 55 IFRSs. However, we follow the strategy of combining radio data with IR and optical data for a large region of the sky. Using these data, we discover a population of >1300 brighter IFRSs which are, for the first time, reliably detected in the infrared and optical. We present the first spectroscopic redshifts of IFRSs and show that the brightest IFRSs are at z > 2. Furthermore, we rule out that IFRSs are Star Forming Galaxies, hotspots, lobes or misidentifications. We find the first X-ray counterparts of IFRSs, and increase the number of known polarised IFRSs five-fold. We present an analysis of their radio spectra and show that IFRSs consist of GPS, CSS and ultra-steep-spectrum sources. We follow up >50 of these using VLBI observations, and confirm the AGN status of IFRSs. GPS and CSS sources are compact radio sources with a convex radio spectrum. They are widely thought to represent young and evolving radio galaxies that have recently launched their jets. However, good evidence exists in individual cases that GPS and CSS sources are one of the following: 1) frustrated by interactions with dense gas and dust in their environment; 2) prematurely dying radio sources; 3) recurrent radio galaxies. Their

  1. The difference between radio-loud and radio-quiet active galaxies

    Science.gov (United States)

    Wilson, A. S.; Colbert, E. J. M.

    1995-01-01

    The recent development of unified theories of active galactic nuclei (AGNs) has indicated that there are two physically distinct classes of these objects--radio-loud and radio-quiet. Despite differences, the (probable) thermal emissions from the AGNs (continua and lines from X-ray to infrared wavelengths) are quite similar to the two classes of object. We argue that this last result suggests that the black hole masses and mass accretion rates in the two classes are not greatly different, and that the difference between the classes is associated with the spin of the black hole. We assume that the normal process of accretion through a disk does not lead to rapidly spinning holes and propose that galaxies (e.g., spirals) which have not suffered a recent major merger event contain nonrotating or only slowly rotating black holes. When two such galaxies merge, the two black holes are known to form a binary and we assume that they eventually coalesce. The ratio of the number of radio-loud to radio-quiet AGNs at a given thermal (e.g., optical) luminosity is determined by the galaxy merger rate. Comparisons between the predicted and observed radio luminosity functions constrain the efficiencies with which jet power is extracted from the spinning hole and radio emission is produced by the jet.

  2. Information Content in Radio Waves: Student Investigations in Radio Science

    Science.gov (United States)

    Jacobs, K.; Scaduto, T.

    2013-12-01

    We describe an inquiry-based instructional unit on information content in radio waves, created in the summer of 2013 as part of a MIT Haystack Observatory (Westford, MA) NSF Research Experiences for Teachers (RET) program. This topic is current and highly relevant, addressing science and technical aspects from radio astronomy, geodesy, and atmospheric research areas as well as Next Generation Science Standards (NGSS). Projects and activities range from simple classroom demonstrations and group investigations, to long term research projects incorporating data acquisition from both student-built instrumentation as well as online databases. Each of the core lessons is applied to one of the primary research centers at Haystack through an inquiry project that builds on previously developed units through the MIT Haystack RET program. In radio astronomy, students investigate the application of a simple and inexpensive software defined radio chip (RTL-SDR) for use in systems implementing a small and very small radio telescope (SRT and VSRT). Both of these systems allow students to explore fundamental principles of radio waves and interferometry as applied to radio astronomy. In ionospheric research, students track solar storms from the initial coronal mass ejection (using Solar Dynamics Observatory images) to the resulting variability in total electron density concentrations using data from the community standard Madrigal distributed database system maintained by MIT Haystack. Finally, students get to explore very long-baseline interferometry as it is used in geodetic studies by measuring crustal plate displacements over time. Alignment to NextGen standards is provided for each lesson and activity with emphasis on HS-PS4 'Waves and Their Applications in Technologies for Information Transfer'.

  3. Study of radio-active ions in the atmosphere

    International Nuclear Information System (INIS)

    Renoux, A.

    1965-01-01

    A comparative study is made of active, deposits of radon and thoron in suspension in the atmosphere by means of α radiation counting, using ZELENY tubes, scattering equipment, filter papers or membranes. It has been possible to show the existence of small and large ions which are negative and positive, as well as of neutral radio-active nuclei; their properties are studied. A theoretical interpretation of the results is presented. The average content of radon (using the Ra A concentration) and of Th B in the air has been determined. The radioactive equilibrium between radon and its daughter products in atmospheric air are examined. The techniques developed for active radon and thoron deposits are applied to the study of artificial radio-activity, the analyses being carried out by means of γ spectrometry. (author) [fr

  4. Cognitive Radio Networks for Tactical Wireless Communications

    Science.gov (United States)

    2014-12-01

    exists. Instead, security is an evolving process, as we have seen in the context of WLANs and 2G / 3G networks. New system vulnerabilities continue to...in the network configuration and radio parameters take place due to mobility of platforms, and variation in other users of the RF environment. CRNs...dynamic spectrum access experimentally, and it represents the largest military Mobile Ad hoc Network (MANET) as of today. The WNaN demonstrator has been

  5. Demonstration of immunochemical identity between the nerve growth factor-inducible large external (NILE) glycoprotein and the cell adhesion molecule L1

    DEFF Research Database (Denmark)

    Bock, E; Richter-Landsberg, C; Faissner, A

    1985-01-01

    The nerve growth factor-inducible large external (NILE) glycoprotein and the neural cell adhesion molecule L1 were shown to be immunochemically identical. Immunoprecipitation with L1 and NILE antibodies of [3H]fucose-labeled material from culture supernatants and detergent extracts of NGF......-treated rat PC12 pheochromocytoma cells yielded comigrating bands by SDS-PAGE. NILE antibodies reacted with immunopurified L1 antigen, but not with N-CAM and other L2 epitope-bearing glycoproteins from adult mouse brain. Finally, by sequential immunoprecipitation from detergent extracts of [35S......]methionine-labeled early post-natal cerebellar cell cultures or [3H]fucose-labeled NGF-treated PC12 cells, all immunoreactivity for NILE antibody could be removed by pre-clearing with L1 antibody and vice versa....

  6. Media Access Time-Rearrangement of Wireless LAN for a Multi-Radio Collocated Platform

    Science.gov (United States)

    Shin, Sang-Heon; Kim, Chul; Park, Sang Kyu

    With the advent of new Radio Access Technologies (RATs), it is inevitable that several RATs will co-exist, especially in the license-exempt band. In this letter, we present an in-depth adaptation of the proactive time-rearrangement (PATRA) scheme for IEEE 802.11 WLAN. The PATRA is a time division approach for reducing interference from a multi-radio device. Because IEEE 802.11 is based on carrier sensing and contention mechanism, it is the most suitable candidate to adapt the PATRA.

  7. 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...) SAFETY AND SPECIAL RADIO SERVICES PERSONAL RADIO SERVICES Radio Control (R/C) Radio Service General Provisions § 95.201 (R/C Rule 1) What is the Radio Control (R/C) Radio Service? The R/C Service is a private...

  8. A Lightweight Radio Propagation Model for Vehicular Communication in Road Tunnels.

    Directory of Open Access Journals (Sweden)

    Muhammad Ahsan Qureshi

    Full Text Available Radio propagation models (RPMs are generally employed in Vehicular Ad Hoc Networks (VANETs to predict path loss in multiple operating environments (e.g. modern road infrastructure such as flyovers, underpasses and road tunnels. For example, different RPMs have been developed to predict propagation behaviour in road tunnels. However, most existing RPMs for road tunnels are computationally complex and are based on field measurements in frequency band not suitable for VANET deployment. Furthermore, in tunnel applications, consequences of moving radio obstacles, such as large buses and delivery trucks, are generally not considered in existing RPMs. This paper proposes a computationally inexpensive RPM with minimal set of parameters to predict path loss in an acceptable range for road tunnels. The proposed RPM utilizes geometric properties of the tunnel, such as height and width along with the distance between sender and receiver, to predict the path loss. The proposed RPM also considers the additional attenuation caused by the moving radio obstacles in road tunnels, while requiring a negligible overhead in terms of computational complexity. To demonstrate the utility of our proposed RPM, we conduct a comparative summary and evaluate its performance. Specifically, an extensive data gathering campaign is carried out in order to evaluate the proposed RPM. The field measurements use the 5 GHz frequency band, which is suitable for vehicular communication. The results demonstrate that a close match exists between the predicted values and measured values of path loss. In particular, an average accuracy of 94% is found with R2 = 0.86.

  9. Relativistic runaway breakdown in low-frequency radio

    Science.gov (United States)

    Füllekrug, Martin; Roussel-Dupré, Robert; Symbalisty, Eugene M. D.; Chanrion, Olivier; Odzimek, Anna; van der Velde, Oscar; Neubert, Torsten

    2010-01-01

    The electromagnetic radiation emitted by an electron avalanche beam resulting from relativistic runaway breakdown within the Earth's atmosphere is investigated. It is found from theoretical modeling with a computer simulation that the electron beam emits electromagnetic radiation which is characterized by consecutive broadband pulses in the low-frequency radio range from ˜10 to 300 kHz at a distance of ˜800 km. Experimental evidence for the existence of consecutive broadband pulses is provided by low-frequency radio observations of sprite-producing lightning discharges at a distance of ˜550 km. The measured broadband pulses occur ˜4-9 ms after the sprite-producing lightning discharge, they exhibit electromagnetic radiation which mainly spans the frequency range from ˜50 to 350 kHz, and they exhibit complex waveforms without the typical ionospheric reflection of the first hop sky wave. Two consecutive pulses occur ˜4.5 ms and ˜3 ms after the causative lightning discharge and coincide with the sprite luminosity. It is concluded that relativistic runaway breakdown within the Earth's atmosphere can emit broadband electromagnetic pulses and possibly generates sprites. The source location of the broadband pulses can be determined with an interferometric network of wideband low-frequency radio receivers to lend further experimental support to the relativistic runaway breakdown theory.

  10. Assessment of Cooperative and Heterogeneous Indoor Localization Algorithms with Real Radio Devices

    DEFF Research Database (Denmark)

    Nielsen, Jimmy Jessen; Noureddine, Hadi; Amiot, Nicolas

    2014-01-01

    In this paper we present results of real-life local- ization experiments performed in an unprecedented cooperative and heterogeneous wireless context. The experiments covered measurements of different radio devices packed together on a trolley, emulating a multi-standard Mobile Terminal (MT) along...... representative trajectories in a crowded office environment. Among all the radio access technologies involved in this campaign (including LTE, WiFi...), the focus is herein put mostly on Impulse Radio - Ultra Wideband (IR-UWB) and ZigBee sub-systems, which are enabled with peer-to-peer ranging capabilities based...... on Time of Arrival (ToA) estimation and Received Signal Strength (RSS) measurements respectively. Single-link model parameters are preliminarily drawn and discussed. In comparison with existing similar campaigns, new algorithms are also applied to the measurement data, showing the interest of advanced de...

  11. The Radio Jove Project

    Science.gov (United States)

    Thieman, J. R.

    2010-01-01

    The Radio love Project is a hands-on education and outreach project in which students, or any other interested individuals or groups build a radio telescope from a kit, operate the radio telescope, transmit the resulting signals through the internet if desired, analyze the results, and share the results with others through archives or general discussions among the observers. Radio love is intended to provide an introduction to radio astronomy for the observer. The equipment allows the user to observe radio signals from Jupiter, the Sun, the galaxy, and Earth-based radiation both natural and man-made. The project was started through a NASA Director's Discretionary Fund grant more than ten years ago. it has continued to be carried out through the dedicated efforts of a group of mainly volunteers. Dearly 1500 kits have been distributed throughout the world. Participation can also be done without building a kit. Pre-built kits are available. Users can also monitor remote radio telescopes through the internet using free downloadable software available through the radiosky.com website. There have been many stories of prize-winning projects, inspirational results, collaborative efforts, etc. We continue to build the community of observers and are always open to new thoughts about how to inspire the observers to still greater involvement in the science and technology associated with Radio Jove.

  12. Radio Sensor for Monitoring of UMTS Mobile Terminals

    Directory of Open Access Journals (Sweden)

    F. Kozak

    2014-06-01

    Full Text Available Relatively simple and low-cost radio sensor for monitoring of 3rd generation (3G UMTS mobile terminals (i.e., phones has been designed and practically tested. The main purpose of this sensor is to serve as an extending module that can be installed into systems used for monitoring of standard 2nd generation (2G GSM and DCS mobile phones in highly guarded buildings and areas. Since the transmitted powers of UMTS mobile terminals can be very low in relation to GSM and DCS specifications, the new UMTS sensor is based on a highly sensitive receiver and additional signal processing. The radio sensor was practically tested in several scenarios representing worst-case mobile terminal - base station relations. The measured detection ranges attain values from approx. 11 m inside of rooms to more than 30 m in corridors, which seems to be sufficient for the expected application. Results of all performed tests correspond fairly well with the presented theoretical descriptions. An extended version of the radio sensor can be used for monitoring of mobile terminals of all existing voice or data formats.

  13. On the Lack of a Radio Afterglow from Some Gamma-Ray Bursts - Insight into Their Progenitors?

    International Nuclear Information System (INIS)

    Lloyd-Ronning, Nicole Marie; Fryer, Christopher L.

    2017-01-01

    We investigate the intrinsic properties of a sample of bright (with isotropic equivalent energy Eiso > 10 52 erg) gamma-ray bursts (GRBs), comparing those with and without radio afterglow. We find that the sample of bursts with no radio afterglows has a significantly shorter mean intrinsic duration of the prompt gamma-ray radiation, and the distribution of this duration is significantly different from those bursts with a radio afterglow. Although the sample with no radio afterglow has on average lower isotropic energy, the lack of radio afterglow does not appear to be a result of simply energetics of the burst, but a reflection of a separate physical phenomenon likely related to the circumburst density profile. We also find a weak correlation between the isotropic gamma-ray energy and intrinsic duration in the sample with no radio afterglow, but not in the sample that have observed radio afterglows. We give possible explanations for why there may exist a sample of GRBs with no radio afterglow depending on whether the radio emission comes from the forward or reverse shock, and why these bursts appear to have intrinsically shorter prompt emission durations. Lastly, we discuss how our results may have implications for progenitor models of GRBs.

  14. Definition imaging of anomalous geologic structure with radio waves

    International Nuclear Information System (INIS)

    Stolarczyk, L.G.

    1990-01-01

    Diamond core drilling from the surface and access drifts are routinely used in acquiring subsurface geologic data. Examination of core from a constellation of drillholes enables the characterization of the prevailing geology in the deposit. Similar geologic members in adjacent drillholes suggest that layered rock continuity exists between drillholes. Mineralogical and physical examination of core along with computer generated stratigraphic cross sections graphically represents the correlation and classification of the rock in the deposit. CW radio waves propagating on ray paths between drillholes have been used to validate the stratigraphic cross section and image anomalous geologic structure between drillholes. This paper compares the crosshole radio wave tomography images of faults in a nuclear waste repository site and a coal seam with the in-mine mapping results

  15. 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.

  16. 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…

  17. Particle content, radio-galaxy morphology, and jet power: all radio-loud AGN are not equal

    Science.gov (United States)

    Croston, J. H.; Ineson, J.; Hardcastle, M. J.

    2018-05-01

    Ongoing and future radio surveys aim to trace the evolution of black hole growth and feedback from active galactic nuclei (AGNs) throughout cosmic time; however, there remain major uncertainties in translating radio luminosity functions into a reliable assessment of the energy input as a function of galaxy and/or dark matter halo mass. A crucial and long-standing problem is the composition of the radio-lobe plasma that traces AGN jet activity. In this paper, we carry out a systematic comparison of the plasma conditions in Fanaroff & Riley class I and II radio galaxies to demonstrate conclusively that their internal composition is systematically different. This difference is best explained by the presence of an energetically dominant proton population in the FRI, but not the FRII radio galaxies. We show that, as expected from this systematic difference in particle content, radio morphology also affects the jet-power/radio-luminosity relationship, with FRII radio galaxies having a significantly lower ratio of jet power to radio luminosity than the FRI cluster radio sources used to derive jet-power scaling relations via X-ray cavity measurements. Finally, we also demonstrate conclusively that lobe composition is unconnected to accretion mode (optical excitation class): the internal conditions of low- and high-excitation FRII radio lobes are indistinguishable. We conclude that inferences of population-wide AGN impact require careful assessment of the contribution of different jet subclasses, particularly given the increased diversity of jet evolutionary states expected to be present in deep, low-frequency radio surveys such as the LOFAR Two-Metre Sky Survey.

  18. Electromagnetic Interference Assessment of CDMA and GSM Wireless Phones to Aircraft Navigation Radios

    Science.gov (United States)

    Ely, Jay J.; Nguyen, Truong X.; Koppen, Sandra V.; Salud, M. Theresa

    2002-01-01

    To address the concern for cellular phone electromagnetic interference (EMI) to aircraft radios, a radiated emission measurement process for CDMA (IS-95) and GSM (ETSI GSM 11.22) wireless handsets was developed. Spurious radiated emissions were efficiently characterized from devices tested in either a semi-anechoic or reverberation chamber, in terms of effective isotropic radiated power. Eight representative handsets (4 GSM, 4 CDMA) were commanded to operate while varying their radio transmitter parameters (power, modulation, etc.). This report provides a detailed description of the measurement process and resulting data, which may subsequently be used by others as a basis of consistent evaluation for cellular/PCS phones, Bluetooth, IEEE802.11b, IEEE802.11a, FRS/GMRS radios, and other portable transmitters. Aircraft interference path loss (IPL) and navigation radio interference threshold data from numerous reference documents, standards, and NASA partnerships were compiled. Using this data, a preliminary risk assessment is provided for CDMA and GSM wireless phone interference to aircraft localizer, Glideslope, VOR, and GPS radio receivers on typical transport airplanes. The report identifies where existing data for device emissions, IPL, and navigation radio interference thresholds needs to be extended for an accurate risk assessment for wireless transmitters in aircraft.

  19. Mean and extreme radio properties of quasars and the origin of radio emission

    Energy Technology Data Exchange (ETDEWEB)

    Kratzer, Rachael M.; Richards, Gordon T. [Department of Physics, Drexel University, Philadelphia, PA (United States)

    2015-02-01

    We investigate the evolution of both the radio-loud fraction (RLF) and (using stacking analysis) the mean radio loudness of quasars. We consider how these properties evolve as a function of redshift and luminosity, black hole (BH) mass and accretion rate, and parameters related to the dominance of a wind in the broad emission-line region. We match the FIRST source catalog to samples of luminous quasars (both spectroscopic and photometric), primarily from the Sloan Digital Sky Survey. After accounting for catastrophic errors in BH mass estimates at high redshift, we find that both the RLF and the mean radio luminosity increase for increasing BH mass and decreasing accretion rate. Similarly, both the RLF and mean radio loudness increase for quasars that are argued to have weaker radiation line driven wind components of the broad emission-line region. In agreement with past work, we find that the RLF increases with increasing optical/UV luminosity and decreasing redshift, while the mean radio loudness evolves in the exact opposite manner. This difference in behavior between the mean radio loudness and the RLF in L−z may indicate selection effects that bias our understanding of the evolution of the RLF; deeper surveys in the optical and radio are needed to resolve this discrepancy. Finally, we argue that radio-loud (RL) and radio-quiet (RQ) quasars may be parallel sequences, but where only RQ quasars at one extreme of the distribution are likely to become RL, possibly through slight differences in spin and/or merger history.

  20. 3D relativistic MHD numerical simulations of X-shaped radio sources

    Science.gov (United States)

    Rossi, P.; Bodo, G.; Capetti, A.; Massaglia, S.

    2017-10-01

    Context. A significant fraction of extended radio sources presents a peculiar X-shaped radio morphology: in addition to the classical double lobed structure, radio emission is also observed along a second axis of symmetry in the form of diffuse wings or tails. In a previous investigation we showed the existence of a connection between the radio morphology and the properties of the host galaxies. Motivated by this connection we performed two-dimensional numerical simulations showing that X-shaped radio sources may naturally form as a jet propagates along the major axis a highly elliptical density distribution, because of the fast expansion of the cocoon along the minor axis of the distribution. Aims: We intend to extend our analysis by performing three-dimensional numerical simulations and investigating the role of different parameters in determining the formation of the X-shaped morphology. Methods: The problem is addressed by numerical means, carrying out three-dimensional relativistic magnetohydrodynamic simulations of bidirectional jets propagating in a triaxial density distribution. Results: We show that only jets with power ≲ 1044 erg s-1 can give origin to an X-shaped morphology and that a misalignment of 30° between the jet axis and the major axis of the density distribution is still favourable to the formation of this kind of morphology. In addition we compute synthetic radio emission maps and polarization maps. Conclusions: In our scenario for the formation of X-shaped radio sources only low power FRII can give origin to such kind of morphology. Our synthetic emission maps show that the different observed morphologies of X-shaped sources can be the result of similar structures viewed under different perspectives.

  1. NAC/NINE Program Building Radio Jove's and Brining Radio Astronomy to the Community

    Science.gov (United States)

    Ramona Gallego, Angelina; Paul Gueye, Al Amin Kabir,

    2018-01-01

    During the course of the 8-week program, (NINE, National and International Non-Traditional Exchange Program), the summer was spent in Socorro, New Mexico, working on building a Radio Jove, and making observations with the Radio Jove as well as working on learning project management practices in order to take the CAPM PMI Exam. The NINE built the Radio Jove’s at the same time and in doing so learned to replicate it to teach it to others. The final portion of the program that was worked on was to create a NINE hub and do outreach with the community teaching them about radio astronomy and teaching students how to build their own Radio Jove’s and make observations. An important aspect of the summer program was to bring back the knowledge received about radio astronomy and teach it to high school students with the help of the institution each NINE participants came from.

  2. Solar radio observations and interpretations

    International Nuclear Information System (INIS)

    Rosenberg, H.

    1976-01-01

    The recent solar radio observations related to flares are reviewed for the frequency range of a few kilohertz to several gigahertz. The analysis of the radio data leads to boundary conditions on the acceleration processes which are responsible for the fast particles which cause radio emission. The role and cause of plasma turbulence at the plasma-frequency and at much lower frequencies is discussed in relation to the acceleration processes and the radio emission mechanisms for the various radio bursts. (author)

  3. Novel reconfigurable wide-beam radio interferometer for space physics instrumentation

    Science.gov (United States)

    Dekoulis, George; Honary, Farideh

    2008-07-01

    This paper describes the instrumentation design of a novel wide-beam interferometer system for radio astronomy studies. The system measures the Earth's or another planet's atmospheric layers attenuation of the highly energetic galactic electron emissions superimposed on the Cosmic Microwave Background (CMB) and other last scattering surface galactic and extragalactic radio astronomical background emissions. Right ascension coordinates are surveyed in a unique manner in terms of digital signal processing flexibility, compared to existing wide-beam instrumentations, allowing higher resolution analysis of the captured Space Physics events. The system provides a prototyping platform for other Space Physics projects, since a modular software and hardware design approach has been followed. The system is reconfigurable to meet a variety of testing scenarios.

  4. Fast Radio Bursts

    Indian Academy of Sciences (India)

    Akshaya Rane

    2017-09-12

    ) 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 ...

  5. Testing the dark matter origin of the WMAP-Planck haze with radio observations of spiral galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, Eric; Linden, Tim; Profumo, Stefano [Department of Physics, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA, 95064 (United States); Hooper, Dan, E-mail: erccarls@ucsc.edu, E-mail: dhooper@fnal.gov, E-mail: tlinden@ucsc.edu, E-mail: profumo@ucsc.edu [Center for Particle Astrophysics, Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States)

    2013-07-01

    If the Galactic WMAP radio haze, as recently confirmed by Planck, is produced by dark matter annihilation or decay, similar diffuse radio halos should exist around other galaxies with physical properties comparable to the Milky Way. If instead the haze is due to an astrophysical mechanism peculiar to the Milky Way or to a transient event, a similar halo need not exist around all Milky Way ''twins''. We use radio observations of 66 spiral galaxies to test the dark matter origin of the haze. We select galaxies based on morphological type and maximal rotational velocity, and obtain their luminosities from a 1.49 GHz catalog and additional radio observations at other frequencies. We find many instances of galaxies with radio emission that is less than 5% as bright as naively expected from dark matter models that could produce the Milky Way haze, and at least 3 galaxies that are less than 1% as bright as expected, assuming dark matter distributions, magnetic fields, and cosmic ray propagation parameters equal to those of the Milky Way. For reasonable ranges for the variation of these parameters, we estimate the fraction of galaxies that should be expected to be significantly less bright in radio, and argue that this is marginally compatible with the observed distribution. While our findings therefore cannot rule out a dark matter origin for the radio haze at this time, we find numerous examples (including the Andromeda Galaxy) where, if dark matter is indeed the origin of the Milky Way haze, some mechanism must be in place to suppress the corresponding haze of the external galaxy. We point out that Planck data will offer opportunities to improve this type of constraint in a highly relevant frequency range and for a potentially larger set of candidate galaxies.

  6. Towards a Fraud-Prevention Framework for Software Defined Radio Mobile Devices

    Directory of Open Access Journals (Sweden)

    Brawerman Alessandro

    2005-01-01

    Full Text Available The superior reconfigurability of software defined radio mobile devices has made it the most promising technology on the wireless network and in the communication industry. Despite several advantages, there are still a lot to discuss regarding security, for instance, the radio configuration data download, storage and installation, user's privacy, and cloning. The objective of this paper is to present a fraud-prevention framework for software defined radio mobile devices that enhances overall security through the use of new pieces of hardware, modules, and protocols. The framework offers security monitoring against malicious attacks and viruses, protects sensitive information, creates and protects an identity for the system, employs a secure protocol for radio configuration download, and finally, establishes an anticloning scheme, which besides guaranteeing that no units can be cloned over the air, also elevates the level of difficulty to clone units if the attacker has physical access to the mobile device. Even if cloned units exist, the anticloning scheme is able to identify and deny services to those units. Preliminary experiments and proofs that analyze the correctness of the fraud-prevention framework are also presented.

  7. The Concept of 'Radio Music'

    DEFF Research Database (Denmark)

    Fjeldsøe, Michael

    2016-01-01

    , educational and didactic effort which would enlighten all of society. For a while it seemed that radio music was considered a genre of its own. To fulfil its function, radio music had to consider technical limitations as well as the educational level and listening modes of the new mass audience. Public radio......, 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....

  8. 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...

  9. Measurement Technique in Radio Frequency Interference (RFI) Study for Radio Astronomy Purposes

    International Nuclear Information System (INIS)

    Roslan Umar; Roslan Umar; Nor Hazmin Sabri; Zainol Abidin Ibrahim; Zamri Zainal Abidin; Asyaari Muhamad

    2015-01-01

    In this paper, we will review our method in making measurements of radio frequency interference (RFI) in order to investigate the sereneness of interference in selected radio interference in Malaysia and Thailand. The selected site are University of Malaya (UM), Universiti Pendidikan Sultan Idris (UPSI), Ubon (UB) and Chiang Mai (CM). The major RFI affecting radio astronomical windows below 1 GHz are electronic equipment system specifically radio navigation between 73.1 MHz and 75.2 MHz, radio broadcasting (151 MHz, 151.8 MHz and 152 MHz), aeronautical navigation (245.5 MHz, 248.7 MHz and 249 MHz and also fixed mobile at 605 MHz, 608.3 MHz, 612.2 MHz, 613.3 MHz. It is obviously showed that all sites within this region are free from interference between 320MHz and 330 MHz and is the best specific region to be considered for solar burst monitoring. We also investigate the effect of RFI on discovery of solar burst. (author)

  10. 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

  11. Radio astronomy

    International Nuclear Information System (INIS)

    Parijskij, Y.N.; Gossachinskij, I.V.; Zuckerman, B.; Khersonsky, V.K.; Pustilnik, S.; Robinson, B.J.

    1976-01-01

    A critical review of major developments and discoveries in the field of radioastronomy during the period 1973-1975 is presented. The report is presented under the following headings:(1) Continuum radiation from the Galaxy; (2) Neutral hydrogen, 21 cm (galactic and extragalactic) and recombination lines; (3) Radioastronomy investigations of interstellar molecules; (4) Extragalactic radio astronomy and (6) Development in radio astronomy instruments. (B.R.H.)

  12. INTERSTELLAR SCINTILLATION AND THE RADIO COUNTERPART OF THE FAST RADIO BURST FRB 150418

    International Nuclear Information System (INIS)

    Akiyama, Kazunori; Johnson, Michael D.

    2016-01-01

    Keane et al. have recently reported the discovery of a new fast radio burst (FRB), FRB 150418, with a promising radio counterpart at 5.5 and 7.5 GHz—a rapidly decaying source, falling from 200–300 μ Jy to 100 μ Jy on timescales of ∼6 days. This transient source may be associated with an elliptical galaxy at redshift z = 0.492, providing the first firm spectroscopic redshift for an FRB and the ability to estimate the density of baryons in the intergalactic medium via the combination of known redshift and radio dispersion of the FRB. An alternative explanation, first suggested by Williams and Berger, is that the identified counterpart may instead be a compact active galactic nucleus (AGN). The putative counterpart’s variation may then instead be extrinsic, caused by refractive scintillation in the ionized interstellar medium of the Milky Way, which would invalidate the association with FRB 150418. We examine this latter explanation in detail and show that the reported observations are consistent with scintillating radio emission from the core of a radio-loud AGN having a brightness temperature T _b ≳ 10"9 K. Using numerical simulations of the expected scattering for the line of sight to FRB 150418, we provide example images and light curves of such an AGN at 5.5 and 7.5 GHz. These results can be compared with continued radio monitoring to conclusively determine the importance of scintillation for the observed radio variability, and they show that scintillation is a critical consideration for continued searches for FRB counterparts at radio wavelengths.

  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. 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. Resonators for magnetohydrodynamic waves in the solar corona: The effect of modulation of radio emission

    International Nuclear Information System (INIS)

    Zaitsev, V.V.; Stepanov, A.V.

    1982-01-01

    It is shown that the existence of a minimum of the Alfven speed in the corona at a height of approx.1R/sub sun/ follows from the characteristics of type II radio bursts. The region of a reduced Alfven speed is a resonator for a fast magnetosonic (FMS) waves. The eigenmodes of the resonator are determined. The period of the fundamental mode has the order of several minutes. In the resonator FMS waves can be excited at the Cherenkov resonance by streams of energetic ions. Modulations of metal solar radio emission with a period of several minutes is explained by the effect of the propagation of radio waves through an oscillating magnetohydrodynamic (MHD) resonator

  16. 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…

  17. Analiza efikasnosti funkcionalnih radio-komunikacionih centara / The efficiency analysis of functional radio communication centers

    Directory of Open Access Journals (Sweden)

    Saša M. Devetak

    2008-10-01

    Full Text Available U radu je prikazan jedan pristup u analizi efikasnosti radio-komunikacionih centara funkcionalnog telekomunikacionog sistema, kao što je vojni sistem veza. Radio-komunikacioni centar modelovan je kao sistem masovnog opsluživanja. Opisana su stanja sistema i parametri i izveden izraz za određivanje verovatnoće opsluživanja radio-komunikacionog centra, kao kriterijuma za ocenu efikasnosti. Predstavljen je, takođe, model, odnosno izrazi za kvantitativnu analizu efikasnosti radio- komunikacionih centara u uslovima elektronskih dejstava. / One approach in the analysis of efficiency of radio communication centers of functional telecommunication systems (for example Military Systems has been shown in this article. A radio communication centre has been presented as a model of mass service systems. The system states and its parameters have been described as well as the resulting formula for determining service probability as a criterion for efficiency evaluation. A model and the formulae for quantitative analysis of efficiency in electronic warfare have been presented as well.

  18. Wide Field Radio Transient Surveys

    Science.gov (United States)

    Bower, Geoffrey

    2011-04-01

    The time domain of the radio wavelength sky has been only sparsely explored. Nevertheless, serendipitous discovery and results from limited surveys indicate that there is much to be found on timescales from nanoseconds to years and at wavelengths from meters to millimeters. These observations have revealed unexpected phenomena such as rotating radio transients and coherent pulses from brown dwarfs. Additionally, archival studies have revealed an unknown class of radio transients without radio, optical, or high-energy hosts. The new generation of centimeter-wave radio telescopes such as the Allen Telescope Array (ATA) will exploit wide fields of view and flexible digital signal processing to systematically explore radio transient parameter space, as well as lay the scientific and technical foundation for the Square Kilometer Array. Known unknowns that will be the target of future transient surveys include orphan gamma-ray burst afterglows, radio supernovae, tidally-disrupted stars, flare stars, and magnetars. While probing the variable sky, these surveys will also provide unprecedented information on the static radio sky. I will present results from three large ATA surveys (the Fly's Eye survey, the ATA Twenty CM Survey (ATATS), and the Pi GHz Survey (PiGSS)) and several small ATA transient searches. Finally, I will discuss the landscape and opportunities for future instruments at centimeter wavelengths.

  19. X rays from radio binaries

    International Nuclear Information System (INIS)

    Apparao, K.M.V.

    1977-01-01

    Reference is made to the radio binary systems CC Cas, AR Lac, β Per (Algol), β Lyr, b Per and Cyg X-1. It is stated that a thermal interpretation of the radiation from Algol requires a much larger x-ray flux than the observed value of 3.8 x 10 -11 erg/cm 2 /sec/keV in the 2 to 6 keV energy range. Observations of some non-thermal flares, together with the small size of the radio source in Algol, indicate that the radio emission is non-thermal in nature. The radio emission is interpreted as synchrotron radiation and it is suggested that the observed x-ray emission is due to inverse Compton scattering of the light of the primary star by the radio electrons. The x-ray emission from other radio binaries is also calculated using this model. The energy for the radio electrons can arise from annihilation of magnetic lines connecting the binary stars, twisted by the rotation of the stars. (U.K.)

  20. Empowering file-based radio production through media asset management systems

    Science.gov (United States)

    Muylaert, Bjorn; Beckers, Tom

    2006-10-01

    In recent years, IT-based production and archiving of media has matured to a level which enables broadcasters to switch over from tape- or CD-based to file-based workflows for the production of their radio and television programs. This technology is essential for the future of broadcasters as it provides the flexibility and speed of execution the customer demands by enabling, among others, concurrent access and production, faster than real-time ingest, edit during ingest, centrally managed annotation and quality preservation of media. In terms of automation of program production, the radio department is the most advanced within the VRT, the Flemish broadcaster. Since a couple of years ago, the radio department has been working with digital equipment and producing its programs mainly on standard IT equipment. Historically, the shift from analogue to digital based production has been a step by step process initiated and coordinated by each radio station separately, resulting in a multitude of tools and metadata collections, some of them developed in-house, lacking integration. To make matters worse, each of those stations adopted a slightly different production methodology. The planned introduction of a company-wide Media Asset Management System allows a coordinated overhaul to a unified production architecture. Benefits include the centralized ingest and annotation of audio material and the uniform, integrated (in terms of IT infrastructure) workflow model. Needless to say, the ingest strategy, metadata management and integration with radio production systems play a major role in the level of success of any improvement effort. This paper presents a data model for audio-specific concepts relevant to radio production. It includes an investigation of ingest techniques and strategies. Cooperation with external, professional production tools is demonstrated through a use-case scenario: the integration of an existing, multi-track editing tool with a commercially available

  1. 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 ...

  2. INTERSTELLAR SCINTILLATION AND THE RADIO COUNTERPART OF THE FAST RADIO BURST FRB 150418

    Energy Technology Data Exchange (ETDEWEB)

    Akiyama, Kazunori [Massachusetts Institute of Technology, Haystack Observatory, Route 40, Westford, MA 01886 (United States); Johnson, Michael D., E-mail: kazu@haystack.mit.edu [Harvard Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

    2016-06-10

    Keane et al. have recently reported the discovery of a new fast radio burst (FRB), FRB 150418, with a promising radio counterpart at 5.5 and 7.5 GHz—a rapidly decaying source, falling from 200–300 μ Jy to 100 μ Jy on timescales of ∼6 days. This transient source may be associated with an elliptical galaxy at redshift z = 0.492, providing the first firm spectroscopic redshift for an FRB and the ability to estimate the density of baryons in the intergalactic medium via the combination of known redshift and radio dispersion of the FRB. An alternative explanation, first suggested by Williams and Berger, is that the identified counterpart may instead be a compact active galactic nucleus (AGN). The putative counterpart’s variation may then instead be extrinsic, caused by refractive scintillation in the ionized interstellar medium of the Milky Way, which would invalidate the association with FRB 150418. We examine this latter explanation in detail and show that the reported observations are consistent with scintillating radio emission from the core of a radio-loud AGN having a brightness temperature T {sub b} ≳ 10{sup 9} K. Using numerical simulations of the expected scattering for the line of sight to FRB 150418, we provide example images and light curves of such an AGN at 5.5 and 7.5 GHz. These results can be compared with continued radio monitoring to conclusively determine the importance of scintillation for the observed radio variability, and they show that scintillation is a critical consideration for continued searches for FRB counterparts at radio wavelengths.

  3. THE RADIO PROPERTIES OF RADIO-LOUD NARROW-LINE SEYFERT 1 GALAXIES ON PARSEC SCALES

    Energy Technology Data Exchange (ETDEWEB)

    Gu, Minfeng; Chen, Yongjun; Shen, Zhiqiang [Shanghai Astronomical Observatory, Chinese Academy of Sciences, Shanghai 200030 (China); Komossa, S.; Zensus, J. A. [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Yuan, Weimin [Key Lab for Space Astronomy and Technology, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Wajima, Kiyoaki [Korea Astronomy and Space Science Institute, 776 Daedeokdae-ro, Yuseong, Daejeon 305-348 (Korea, Republic of); Zhou, Hongyan, E-mail: gumf@shao.ac.cn [Polar Research Institute of China, 451 Jinqiao Road, Shanghai 200136 (China)

    2015-11-15

    We present the detection of the compact radio structures of 14 radio-loud narrow-line Seyfert 1 (NLS1) galaxies from Very Long Baseline Array (VLBA) observations at 5 GHz performed in 2013. While 50% of the sources of our sample show a compact core only, the remaining 50% exhibit a core-jet structure. The measured brightness temperatures of the cores range from 10{sup 8.4} to 10{sup 11.4} K with a median value of 10{sup 10.1} K, indicating that the radio emission is from non-thermal jets, and that, likely, most sources are not strongly beamed, thus implying a low jet speed in these radio-loud NLS1 galaxies. In combination with archival data taken at multiple frequencies, we find that seven sources show flat or even inverted radio spectra, while steep spectra are revealed in the remaining seven objects. Although all of these sources are very radio-loud with R > 100, their jet properties are diverse in terms of their milliarcsecond (mas) scale (parsec scale) morphology and their overall radio spectral shape. The evidence for slow jet speeds (i.e., less relativistic jets), in combination with the low kinetic/radio power, may offer an explanation for the compact VLBA radio structure in most sources. The mildly relativistic jets in these high accretion rate systems are consistent with a scenario where jets are accelerated from the hot corona above the disk by the magnetic field and the radiation force of the accretion disk. Alternatively, a low jet bulk velocity can be explained by low spin in the Blandford–Znajek mechanism.

  4. Immunochemical and biological characterization of outer membrane proteins of Porphyromonas endodontalis.

    Science.gov (United States)

    Ogawa, T; Kuribayashi, S; Shimauchi, H; Toda, T; Hamada, S

    1992-01-01

    Outer membrane proteins (OMP) of Porphyromonas endodontalis HG 370 (ATCC 35406) were prepared from the cell envelope fraction of the organisms. The cell envelope that had been obtained by sonication of the whole cells was extracted in 2% lithium dodecyl sulfate and then successively chromatographed with Sephacryl S-200 HR and DEAE-Sepharose Fast Flow. Two OMP fractions, OMP-I and OMP-II, were obtained, and their immunochemical properties and induction of specific antibodies were examined. The OMP-I preparation consisted of a major protein with an apparent molecular mass of 31 kDa and other moderate to minor proteins of 40.3, 51.4, 67, and 71.6 kDa, while the OMP-II preparation contained 14-, 15.5-, 27-, and 44-kDa proteins as revealed by sodium dodecyl sulfate-polyacrylamide gel electrophoretic analysis. OMP-I was found to form hydrophilic diffusion pores by incorporation into artificial liposomes composed of egg yolk phosphatidylcholine and dicetylphosphate, indicating that OMP-I exhibited significant porin activity. However, the liposomes containing heat-denatured OMP-I were scarcely active. Spontaneous and antigen-specific immunoglobulin M (IgM)-, IgG-, and IgA-secreting spot-forming cells (SFC) enzymatically dissociated into single-cell suspensions from chronically inflamed periapical tissues and were enumerated by enzyme-linked immunospot assay. In patients with radicular cysts or dental granulomas, the major isotype of spontaneous SFC was IgG. In radicular cysts, the OMP-II-specific IgG SFC represented 0.13% of the total IgG SFC, while the antigen-specific IgA or IgM SFC was not observed. It was also found that none of these mononuclear cells produced antibodies specific for OMP-I or lipopolysaccharide of P. endodontalis. Images PMID:1328059

  5. 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.

  6. 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.

  7. Can Radio Telescopes Find Axions?

    Science.gov (United States)

    Kohler, Susanna

    2017-08-01

    In the search for dark matter, the most commonly accepted candidates are invisible, massive particles commonly referred to as WIMPs. But as time passes and we still havent detected WIMPs, alternative scenarios are becoming more and more appealing. Prime among these is the idea of axions.A Bizarre ParticleThe Italian PVLAS is an example of a laboratory experiment that attempted to confirm the existence of axions. [PVLAS]Axions are a type of particle first proposed in the late 1970s. These theorized particles arose from a new symmetry introduced to solve ongoing problems with the standard model for particle physics, and they were initially predicted to have more than a keV in mass. For this reason, their existence was expected to be quickly confirmed by particle-detector experiments yet no detections were made.Today, after many unsuccessful searches, experiments and theory tell us that if axions exist, their masses must lie between 10-610-3 eV. This is minuscule an electrons mass is around 500,000 eV, and even neutrinos are on the scale of a tenth of an eV!But enough of anything, even something very low-mass, can weigh a lot. If they are real, then axions were likely created in abundance during the Big Bang and unlike heavier particles, they cant decay into anything lighter, so we would expect them all to still be around today. Our universe could therefore be filled with invisible axions, potentially providing an explanation for dark matter in the form of many, many tiny particles.Artists impression of the central core of proposed Square Kilometer Array antennas. [SKA/Swinburne Astronomy Productions]How Do We Find Them?Axions barely interact with ordinary matter and they have no electric charge. One of the few ways we can detect them is with magnetic fields: magnetic fields can change axions to and from photons.While many studies have focused on attempting to detect axions in laboratory experiments, astronomy provides an alternative: we can search for cosmological

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

    DEFF Research Database (Denmark)

    Aatrokoski, J.; Lähteenmäki, A.; Lavonen, N.

    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 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, shape the radio spectra as they move in the relativistic jet. 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...

  9. Immunochemical method for quantitative evaluation of vasogenic brain edema following cold injury of rat brain

    Energy Technology Data Exchange (ETDEWEB)

    Bodsch, W; Huerter, T; Hossmann, K A [Max-Planck-Institut fuer Hirnforschung, Koeln (Germany, F.R.). Forschungsstelle fuer Hirnkreislauf-Forschung

    1982-10-07

    An immunochemical method is described for quantitative assessment of serum proteins and hemoglobin content in brain tissue homogenates. Using a combination of affinity chromatography and radioimmunoassay, the sensitivity of the method is 50 ng hemoglobin and 100 ng serum protein per assay, respectively. The method was used to measure cerebral hematocrit, blood volume and serum protein extravasation in rat brain at various times following cold injury. In control rats cerebral blood volume was 6.88 +- 0.15 ml/100 g and cerebral hematocrit 26.4 +- 0.86% (means +- S.E.). Following cold injury blood volume did not significantly change, but there was a gradual increase of extravasated serum proteins, reaching a maximum of 21.54 +- 2.76 mg/g d.w. after 8 hours. Thereafter protein content gradually declined, but even after 64 h it was distinctly increased. Protein extravasation was partly dissociated from the increase of brain water and sodium which reached a maximum already after 2 h and which normalized within 32 and 64 h, respectively. It is concluded that edema fluid associated with cold injury is not simply an ultrafiltrate of blood serum but consists of cytotoxic and vasogenic components which follow a different time course both during formation and resolution of edema.

  10. Immunochemical method for quantitative evaluation of vasogenic brain edema following cold injury of rat brain

    International Nuclear Information System (INIS)

    Bodsch, W.; Huerter, T.; Hossmann, K.-A.

    1982-01-01

    An immunochemical method is described for quantitative assessment of serum proteins and hemoglobin content in brain tissue homogenates. Using a combination of affinity chromatography and radioimmunoassay, the sensitivity of the method is 50 ng hemoglobin and 100 ng serum protein per assay, respectively. The method was used to measure cerebral hematocrit, blood volume and serum protein extravasation in rat brain at various times following cold injury. In control rats cerebral blood volume was 6.88 +- 0.15 ml/100 g and cerebral hematocrit 26.4 +- 0.86% (means +- S.E.). Following cold injury blood volume did not significantly change, but there was a gradual increase of extravasated serum proteins, reaching a maximum of 21.54 +- 2.76 mg/g d.w. after 8 hours. Thereafter protein content gradually declined, but even after 64 h it was distinctly increased. Protein extravasation was partly dissociated from the increase of brain water and sodium which reached a maximum already after 2 h and which normalized within 32 and 64 h, respectively. It is concluded that edema fluid associated with cold injury is not simply an ultrafiltrate of blood serum but consists of cytotoxic and vasogenic components which follow a different time course both during formation and resolution of edema. (Auth.)

  11. SURVEY PERILAKU MENDENGARKAN RADIO DI JAKARTA

    Directory of Open Access Journals (Sweden)

    Siti Dewi Sri Ratna Sari

    2016-05-01

    Full Text Available This research is to find out the profile of radio broadcasting’s content in Jakarta and to look for measured data as the parameter to assess radio broadcasting programs and the radio listeners profile in DKI Jakarta. The research methodology is survey with 1000 respondents as the sample with 2.24% margin of error and 95% credibility level. The sampling method used is Multistage Random Sampling from 5 out of 6 DKI Jakarta Province areas, except Thousand Islands Regency. Data collection technique used is face to face personal interview by giving gift to the respondents. Research result describes the profile of radio listeners is middle class productive age working men and women whose prime reason listening to radio is music as their pastime. Respondents are categorized as medium listeners with 1.87 hour as their average of listening to radio. Nevertheless, the prime time is covering the whole day both while they are listening at home and while they are mobile. Research found that respondents are already satisfied by the radio programs in Jakarta. The competition of radio stations in Jakarta based on their listeners is Gen FM at the top with 44.6%, followed by Bens Radio, Elshinta, I-Radio, Prambors, CBB, and so on. An interesting finding is that radio’s function to deliver social communication is fulfilled by placing religious speech and information as the second and the third most preferable programs with 9.8% and 8.0% below music program.   Penelitian ini bertujuan untuk mengetahui profil isi siaran radio yang selama ini bersiaran di Jakarta sekaligus mencari data terukur sebagai parameter untuk melakukan penilaian terhadap program isi siaran radio, termasuk pola mendengarkan radio pendengar radio seperti durasi dan tempat di provinsi DKI Jakarta. Metode penelitian berupa survei dengan sampel yang diambil sebanyak 1000 responden, margin of error 2.24% dan tingkat kepercayaan 95%. Metode pengambilan sampel dalam penelitian ini adalah dengan

  12. A tale of two feedbacks: Star formation in the host galaxies of radio AGNs

    Energy Technology Data Exchange (ETDEWEB)

    Karouzos, Marios; Im, Myungshin; Jeon, Yiseul; Kim, Ji Hoon [CEOU-Astronomy Program, Department of Physics and Astronomy, Seoul National University, Gwanak-gu, Seoul (Korea, Republic of); Trichas, Markos [Airbus Defence and Space, Gunnels Wood Road, Stevenage SG1 2AS (United Kingdom); Goto, Tomo [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Malkan, Matt [Division of Astronomy and Astrophysics, 3-714 UCLA, CA 90095-1547 (United States); Ruiz, Angel [Inter-University Centre for Astronomy and Astrophysics (IUCAA), Post Bag 4, Ganeshkhind, 411 007 Pune (India); Lee, Hyung Mok; Kim, Seong Jin [Astronomy Program, Department of Physics and Astronomy, Seoul National University, Gwanak-gu, Seoul (Korea, Republic of); Oi, Nagisa; Matsuhara, Hideo; Takagi, Toshinobu; Murata, K.; Wada, Takehiko; Wada, Kensuke [Institute of Space and Astronautical Science, JAXA, Yoshino-dai 3-1-1, Sagamihara, Kanagawa 229-8510 (Japan); Shim, Hyunjin [Department of Earth Science Education, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Hanami, Hitoshi [Physics Section, Faculty of Humanities, Iwate University, Ueda 3 chome, 18-34 Morioka, Morioka, Iwate 020-8550 (Japan); Serjeant, Stephen; White, Glenn J., E-mail: mkarouzos@astro.snu.ac.kr [Department of Physics and Astronomy, The Open University, Walton Hall, Milton Keynes (United Kingdom); and others

    2014-04-01

    Several lines of argument support the existence of a link between activity at the nuclei of galaxies, in the form of an accreting supermassive black hole, and star formation activity in these galaxies. Radio jets have long been argued to be an ideal mechanism that allows active galactic nuclei (AGNs) to interact with their host galaxies and affect star formation. We use a sample of radio sources in the North Ecliptic Pole (NEP) field to study the nature of this putative link, by means of spectral energy distribution (SED) fitting. We employ the excellent spectral coverage of the AKARI infrared space telescope and the rich ancillary data available in the NEP to build SEDs extending from UV to far-IR wavelengths. We find a significant AGN component in our sample of relatively faint radio sources (radio luminosity. In contrast, for narrow redshift and AGN luminosity ranges, we find that increasing radio luminosity leads to a decrease in the specific star formation rate. The most radio-loud AGNs are found to lie on the main sequence of star formation for their respective redshifts. For the first time, we potentially see such a two-sided feedback process in the same sample. We discuss the possible suppression of star formation, but not total quenching, in systems with strong radio jets, that supports the maintenance nature of feedback from radio AGN jets.

  13. 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...

  14. Incentivize Spectrum Leasing in Cognitive Radio Networks by Exploiting Cooperative Retransmission

    Directory of Open Access Journals (Sweden)

    Xiaoyan Wang

    2015-07-01

    Full Text Available This paper addresses the spectrum leasing issue in cognitive radio networks by exploiting the secondary user’s cooperative retransmission. In contrast with the previous researches that focuses on cancellationbased or coding-based cooperative retransmissions, we propose a novel trading-based mechanism to facilitate the cooperative retransmission for cognitive radio networks. By utilizing the Stackelberg game model, we incentivize the otherwise non-cooperative users by maximizing their utilities in terms of transmission rates and economic profit. We analyze the existence of the unique Nash equilibrium of the game, and provide the optimal solutions with corresponding constraints. Numerical results demonstrate the efficiency of the proposed mechanism, under which the performance of the whole system could be substantially improved.

  15. 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

  16. 225m Outdoor W-Band Radio-over-Fiber Link Using an Optical SFP+ Module

    DEFF Research Database (Denmark)

    Rommel, Simon; Rodríguez Páez, Juan Sebastián; Chorchos, Łukasz

    2016-01-01

    A W-band radio-over-fiber link based on a commercial SFP+ module is demonstrated, allowing easy integration into existing PON solutions. Without active laser control good RF frequency stability and 225m wireless distance are achieved...

  17. DISCOVERY OF RADIO AFTERGLOW FROM THE MOST DISTANT COSMIC EXPLOSION

    International Nuclear Information System (INIS)

    Chandra, Poonam; Frail, Dale A.; Fox, Derek; Kulkarni, Shrinivas; Harrsion, Fiona; Kasliwal, Mansi; Berger, Edo; Cenko, S. Bradley; Bock, Douglas C.-J.

    2010-01-01

    We report on the discovery of radio afterglow emission from the gamma-ray burst GRB 090423, which exploded at a redshift of 8.3, making it the object with the highest known redshift in the universe. By combining our radio measurements with existing X-ray and infrared observations, we estimate the kinetic energy of the afterglow, the geometry of the outflow, and the density of the circumburst medium. Our best-fit model suggests a quasi-spherical, high-energy explosion in a low, constant-density medium. GRB 090423 had a similar energy release to the other well-studied high redshift GRB 050904 (z = 6.26), but their circumburst densities differ by 2 orders of magnitude. We compare the properties of GRB 090423 with a sample of gamma-ray bursts (GRBs) at moderate redshifts. We find that the high energy and afterglow properties of GRB 090423 are not sufficiently different from other GRBs to suggest a different kind of progenitor, such as a Population III (Pop III) star. However, we argue that it is not clear that the afterglow properties alone can provide convincing identification of Pop III progenitors. We suggest that the millimeter and centimeter radio detections of GRB 090423 at early times contained emission from the reverse shock. If true, this may have important implications for the detection of high-redshift GRBs by the next generation of radio facilities.

  18. IS THERE AN UNACCOUNTED FOR EXCESS IN THE EXTRAGALACTIC COSMIC RADIO BACKGROUND?

    Energy Technology Data Exchange (ETDEWEB)

    Subrahmanyan, Ravi [Raman Research Institute, CV Raman Avenue, Sadashivanagar, Bangalore 560080 (India); Cowsik, Ramanath, E-mail: rsubrahm@rri.res.in, E-mail: cowsik@physics.wustl.edu [Physics Department and McDonnell Center for the Space Sciences, Washington University, Campus Box 1105, St. Louis, MO 63130 (United States)

    2013-10-10

    Analyses of the distribution of absolute brightness temperature over the radio sky have recently led to suggestions that there exists a substantial unexplained extragalactic radio background. Consequently, there have been numerous attempts to place constraints on plausible origins of this 'excess'. We suggest here that this expectation of a large extragalactic background, over and above that contributed by the sources observed in the surveys, is based on an extremely simple geometry adopted to model the Galactic emission and the procedure adopted in the estimation of the extragalactic contribution. In this paper, we derive the extragalactic radio background from wide-field radio images using a more realistic modeling of the Galactic emission and decompose the sky maps at 150, 408, and 1420 MHz into anisotropic Galactic and isotropic extragalactic components. The anisotropic Galactic component is assumed to arise from a highly flattened spheroid representing the thick disk, embedded in a spherical halo, both centered at the Galactic center, along with Galactic sources, filamentary structures, and Galactic loops and spurs. All components are constrained to be positive and the optimization scheme minimizes the sky area occupied by the complex filaments. We show that in contrast with simple modeling of Galactic emission as a plane parallel slab, the more realistic modeling yields estimates for the uniform extragalactic brightness that are consistent with expectations from known extragalactic radio source populations.

  19. DISCOVERY OF LOW DM FAST RADIO TRANSIENTS: GEMINGA PULSAR CAUGHT IN THE ACT

    International Nuclear Information System (INIS)

    Maan, Yogesh

    2015-01-01

    We report the discovery of several energetic radio bursts at 34 MHz, using the Gauribidanur radio telescope. The radio bursts exhibit two important properties associated with the propagation of astronomical signals through the interstellar medium: (i) frequency dependent dispersive delays across the observing bandwidth and (ii) Faraday rotation of the plane of linear polarization. These bursts sample a range of dispersion measures (DM; 1.4–3.6 pc cm −3 ) and show DM-variation at timescales of the order of a minute. Using groups of bursts having a consistent DM, we show that the bursts have originated from the radio-quiet gamma-ray pulsar Geminga. Detection of these bursts supports the existence of occasional radio emission from Geminga. The rare occurrence of these bursts, and the short timescale variation in their DM (if really caused by the intervening medium or the pulsar magnetosphere), might provide clues as to why the pulsar has not been detected in earlier sensitive searches. We present details of the observations and search procedure used to discover these bursts, a detailed analysis of their properties, and evidences of these bursts being associated with Geminga pulsar, and briefly discuss the possible emission mechanism of these bursts

  20. DISCOVERY OF LOW DM FAST RADIO TRANSIENTS: GEMINGA PULSAR CAUGHT IN THE ACT

    Energy Technology Data Exchange (ETDEWEB)

    Maan, Yogesh, E-mail: ymaan@ncra.tifr.res.in [National Centre for Radio Astrophysics, Pune 411007 (India)

    2015-12-20

    We report the discovery of several energetic radio bursts at 34 MHz, using the Gauribidanur radio telescope. The radio bursts exhibit two important properties associated with the propagation of astronomical signals through the interstellar medium: (i) frequency dependent dispersive delays across the observing bandwidth and (ii) Faraday rotation of the plane of linear polarization. These bursts sample a range of dispersion measures (DM; 1.4–3.6 pc cm{sup −3}) and show DM-variation at timescales of the order of a minute. Using groups of bursts having a consistent DM, we show that the bursts have originated from the radio-quiet gamma-ray pulsar Geminga. Detection of these bursts supports the existence of occasional radio emission from Geminga. The rare occurrence of these bursts, and the short timescale variation in their DM (if really caused by the intervening medium or the pulsar magnetosphere), might provide clues as to why the pulsar has not been detected in earlier sensitive searches. We present details of the observations and search procedure used to discover these bursts, a detailed analysis of their properties, and evidences of these bursts being associated with Geminga pulsar, and briefly discuss the possible emission mechanism of these bursts.

  1. Combined synthetic x-ray and radio observations of simulated radio jets

    Energy Technology Data Exchange (ETDEWEB)

    Tregillis, I. L. (Ian L.); Jones, T. W. (Thomas Walter),; Ryu, Dongsu

    2004-01-01

    We present results from an extensive synthetic observation analysis of numerically-simulated radio galaxy jets. This is the first such analysis to be based on simulations with sufficient physical detail to allow the application of standard observational analysis techniques to simulated radio galaxies. Here we focus on extracting magnetic field properties from nonthermal intensity information. We study field values obtained via the combination of synchrotron radio and inverse-Compton X-ray data as well as those from the minimum-energy approach. The combined radio/X-ray technique provides meaningful information about the field. The minimum-energy approach retrieves reasonable field estimates in regions physically close to the minimum-energy partitioning, though the technique is highly susceptible to deviations from the underlying assumptions. We also look at how the two field measurement techniques might be combined to provide a rough measure of the actual energy in particles and fields. A full report on this work can be found in the Astrophysical Journal, v601, p778.

  2. First Ionospheric Results From the MAVEN Radio Occultation Science Experiment (ROSE)

    Science.gov (United States)

    Withers, Paul; Felici, M.; Mendillo, M.; Moore, L.; Narvaez, C.; Vogt, M. F.; Jakosky, B. M.

    2018-05-01

    Radio occultation observations of the ionosphere of Mars can span the full vertical extent of the ionosphere, in contrast to in situ measurements that rarely sample the main region of the ionosphere. However, most existing radio occultation electron density profiles from Mars were acquired without clear context for the solar forcing or magnetospheric conditions, which presents challenges for the interpretation of these profiles. Here we present 48 ionospheric electron density profiles acquired by the Mars Atmosphere and Volatile EvolutioN mission (MAVEN) Radio Occultation Science Experiment (ROSE) from 5 July 2016 to 27 June 2017 at solar zenith angles of 54° to 101°. Latitude coverage is excellent, and comprehensive context for the interpretation of these profiles is provided by other MAVEN instruments. The profiles show a 9-km increase in ionospheric peak altitude in January 2017 that is associated with a lower atmospheric dust storm, variations in electron densities in the M1 layer that cannot be explained by variations in the solar soft X-ray flux, and topside electron densities that are larger in strongly magnetized regions than in weakly magnetized regions. MAVEN Radio Occultation Science Experiment electron density profiles are publicly available on the NASA Planetary Data System.

  3. 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....... Finally, a flexible metadata schema is suggested, that includes both general metadata and highly media and research project specific metadata....

  4. The Feasibility of Radio Direction Finding for Swarm Localization

    Science.gov (United States)

    2017-09-01

    small swarm agents do not exist. This has led ARL to begin development of a custom RDF system using small, standalone, software-defined radios (SDRs...First, basic RDF theory is presented. Next, a laboratory experiment to evaluate RDF using a SDR is developed. Finally, experimental data are presented... relationships between many agents to achieve accurate relative attitude and position information.1 This is particularly important in GPS-denied environments

  5. FOREWORD: Radio and Antenna Days of the Indian Ocean (RADIO 2012)

    Science.gov (United States)

    Monebhurrun, Vikass; Lesselier, Dominique

    2013-04-01

    It was an honor and a great pleasure for all those involved in its organization to welcome the participants to the 'Radio and Antenna Days of the Indian Ocean' (RADIO 2012) international conference that was held from 24th to 27th September 2012 at the Sugar Beach Resort, Wolmar, Flic-en-Flac, Mauritius. RADIO 2012 is the first of a series of conferences that is to be regularly organized in the Indian Ocean region. The aim is to discuss recent developments, theories and practical applications covering the whole scope of radio-frequency engineering, including radio waves, antennas, propagation, and electromagnetic compatibility. Following discussions with engineers and scientists from the countries of the Indian Ocean as well as from other parts of the world, a need was felt for the organization of such an international event in this region. The Island of Mauritius, worldwide known for its white sandy beaches and pleasant tropical atmosphere, provided an excellent environment for the organization of the 1st RADIO international conference. The Local Organizing Committee consisted of scientists from SUPELEC, the University of Mauritius, and the University of Technology, Mauritius. Various members of staff of the University of Mauritius provided help for the organization of the conference. The International Union of Radio Science (URSI) made available technical and financial sponsorship for partial support of young scientists. A number of companies also supported RADIO 2012 ('Platinum': GSMA, ICTA & MMF, 'Gold': CST & FEKO). The event itself was organized in a premier hotel on Mauritius. In this foreword, we would like to take the opportunity again to thank all the people, institutions and companies that made the event such a success. More than 120 abstracts were submitted to the conference and were peer-reviewed by an international scientific committee. RADIO 2012 overall featured six oral sessions, one poster session and two workshops. Three internationally recognized

  6. Time delay of the PeV gamma ray burst after the October 1985 radio flare of Cygnus X-3

    Energy Technology Data Exchange (ETDEWEB)

    Berezinsky, V S

    1988-08-11

    Cygnus X-3 remains a puzzling and controversial source of ultra-high-energy radiation, E greater than or equal to 0.1 PeV. In existing data, TeV and sometimes PeV radiation has been seen episodically; such an episode is connected with the radio flare of Cyg X-3 in October 1985, when PeV radiation with no phase structure was seen. The PeV pulse was detected 3-5 days after the radio flare. The author proposes a natural explanation for the delay, in which gamma-photons of PeV energy are absorbed by radio radiation inside the source. After a delay, the gamma radiation emerges as the radio flux diminishes and absorption decreases.

  7. THE VLA SURVEY OF CHANDRA DEEP FIELD SOUTH. V. EVOLUTION AND LUMINOSITY FUNCTIONS OF SUB-MILLIJANSKY RADIO SOURCES AND THE ISSUE OF RADIO EMISSION IN RADIO-QUIET ACTIVE GALACTIC NUCLEI

    International Nuclear Information System (INIS)

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

    2011-01-01

    We present the evolutionary properties and luminosity functions of the radio sources belonging to the Chandra Deep Field South Very Large Array survey, which reaches a flux density limit at 1.4 GHz of 43 μJy at the field center and redshift ∼5 and which includes the first radio-selected complete sample of radio-quiet active galactic nuclei (AGNs). We use a new, comprehensive classification scheme based on radio, far- and near-IR, optical, and X-ray data to disentangle star-forming galaxies (SFGs) from AGNs and radio-quiet from radio-loud AGNs. We confirm our previous result that SFGs become dominant only below 0.1 mJy. The sub-millijansky radio sky turns out to be a complex mix of SFGs and radio-quiet AGNs evolving at a similar, strong rate; non-evolving low-luminosity radio galaxies; and declining radio powerful (P ∼> 3 x 10 24 W Hz -1 ) AGNs. Our results suggest that radio emission from radio-quiet AGNs is closely related to star formation. The detection of compact, high brightness temperature cores in several nearby radio-quiet AGNs can be explained by the coexistence of two components, one non-evolving and AGN related and one evolving and star formation related. Radio-quiet AGNs are an important class of sub-millijansky sources, accounting for ∼30% of the sample and ∼60% of all AGNs, and outnumbering radio-loud AGNs at ∼< 0.1 mJy. This implies that future, large area sub-millijansky surveys, given the appropriate ancillary multiwavelength data, have the potential of being able to assemble vast samples of radio-quiet AGNs, bypassing the problems of obscuration that plague the optical and soft X-ray bands.

  8. Radio morphing - towards a full parametrisation of the radio signal from air showers

    Science.gov (United States)

    Zilles, A.; Charrier, D.; Kotera, K.; Le Coz, S.; Martineau-Huynh, O.; Medina, C.; Niess, V.; Tueros, M.; de Vries, K.

    2017-12-01

    Over the last decades, radio detection of air showers has been established as a detection technique for ultra-high-energy cosmic-rays impinging on the Earth's atmosphere with energies far beyond LHC energies. Today’s second-generation of digital radio-detection experiments, as e.g. AERA or LOFAR, are becoming competitive in comparison to already standard techniques e.g. fluorescence light detection. Thanks to a detailed understanding of the physics of the radio emission in extensive air showers, simulations of the radio signal are already successfully tested and applied in the reconstruction of cosmic rays. However the limits of the computational power resources are easily reached when it comes to computing electric fields at the numerous positions requested by large or dense antenna arrays. In the case of mountainous areas as e.g. for the GRAND array, where 3D shower simulations are necessary, the problem arises with even stronger acuity. Therefore we developed a full parametrisation of the emitted radio signal on the basis of generic shower simulations which will reduce the simulation time by orders of magnitudes. In this talk we will present this concept after a short introduction to the concept of the radio detection of air-shower induced by cosmic rays.

  9. 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.

  10. Astronomers Win Protection for Key Part of Radio Spectrum

    Science.gov (United States)

    2000-06-01

    International Telecommunication Union meet to painstakingly parcel out the radio frequency spectrum between radio-based applications such as personal communications, satellite broadcasting, GPS and amateur radio, and the sciences of radio astronomy, earth exploration and deep space research. The WRC also coordinates sharing between services in the same radio bands. WRC decisions are incorporated into the Radio Regulations that govern radio services worldwide. The new spectrum allocations for radio astronomy are the first since 1979. Millimeter-wave astronomy was then in its infancy and many of its needs were not yet known. As astronomers began to explore this region of the spectrum they found spectral lines from many interesting molecules in space. Many of those lines had not fallen into the areas originally set aside for astronomy, but most will be under the new allocations. "It's a win for millimeter-wave science," said Dr. John Whiteoak of the Australia Telescope National Facility, Australian delegate to WRC-00. "This secures its future." The protection is a significant step for both existing millimeter-wave telescopes and new ones such as the Atacama Large Millimeter Array (ALMA) now being planned by a U.S.-European consortium. Even at its isolated site in Chile's Atacama desert, ALMA would be vulnerable to interference from satellite emissions. Sensitive radio astronomy receivers are blinded by these emissions, just as an optical telescope would be by a searchlight. "There is more energy at millimeter and sub-millimeter wavelengths washing through the Universe than there is of light or any other kind of radiation," said ALMA Project Scientist, Dr. Al Wootten of the National Radio Astronomy Observatory. "Imaging the sources of this energy can tell us a great deal about the formation of stars and galaxies, and even planets." "But the Earth's atmosphere isn't very kind to us - it has only a few windows at these frequencies, and not very transparent ones at that. They are

  11. On the evaluation of Web Radio

    OpenAIRE

    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.

  12. Potential game theory applications in radio resource allocation

    CERN Document Server

    Lã, Quang Duy; Soong, Boon-Hee

    2016-01-01

    This book offers a thorough examination of potential game theory and its applications in radio resource management for wireless communications systems and networking. The book addresses two major research goals: how to identify a given game as a potential game, and how to design the utility functions and the potential functions with certain special properties in order to formulate a potential game. After proposing a unifying mathematical framework for the identification of potential games, the text surveys existing applications of this technique within wireless communications and networking problems found in OFDMA 3G/4G/WiFi networks, as well as next-generation systems such as cognitive radios and dynamic spectrum access networks. Professionals interested in understanding the theoretical aspect of this specialized field will find Potential Game Theory a valuable resource, as will advanced-level engineering students. It paves the way for extensive and rigorous research exploration on a topic whose capacity for...

  13. Radio frequency system for nuclear fusion

    International Nuclear Information System (INIS)

    Kozeki, Shoichiro; Sagawa, Norimoto; Takizawa, Teruhiro

    1987-01-01

    The importance of radio frequency waves has been increasing in the area of nuclear fusion since they are indispensable for heating of plasma, etc. This report outlines radio frequency techniques used for nuclear fusion and describes the development of radio frequency systems (radio frequency plasma heating system and current drive system). Presently, in-depth studies are underway at various research institutes to achieve plasma heating by injection of radio frequency electric power. Three ranges of frequencies, ICRF (ion cyclotron range of frequency), LHRF (lower hybrid range of frequency) and ECRF (electron cyclotron range of frequency), are considered promissing for radio frequency heating. Candidate waves for plasma current driving include ECW (electron cyclotron wave), LHW (lower hybrid wave), MSW (magnetic sound wave), ICW (ion cyclotron wave) with minority component, and FW (fast wave). FW is the greatest in terms of current drive efficiency. In general, a radio frequency system for nuclear fusion consists of a radio frequency power source, transmission/matching circuit component and plasma connection component. (Nogami, K.)

  14. Writing for Radio.

    Science.gov (United States)

    Tupper, Marianna S.

    1995-01-01

    Describes a 24-hour commercial radio station simulation class project for eighth-grade language arts. Students wrote their own scripts, chose music and were disc jockeys on their own music and talk shows, and prepared news and traffic reports. Guest speakers from actual commercial radio came in to discuss issues such as advertising, censorship,…

  15. Pair-Matching of Radio-Loud and Radio-Quiet AGNs

    Energy Technology Data Exchange (ETDEWEB)

    Kozieł-Wierzbowska, Dorota [Astronomical Observatory, Jagiellonian University, Krakow (Poland); Stasińska, Grażyna [LUTH, Observatoire de Paris, Centre National de la Recherche Scientifique, Université Paris Diderot, Meudon (France); Vale Asari, Natalia [Departamento de Física–CFM, Universidade Federal de Santa Catarina, Florianópolis (Brazil); Sikora, Marek [Nicolaus Copernicus Astronomical Center, Warsaw (Poland); Goettems, Elisa [Departamento de Física–CFM, Universidade Federal de Santa Catarina, Florianópolis (Brazil); Wójtowicz, Anna, E-mail: dorota.koziel@uj.edu.pl [Astronomical Observatory, Jagiellonian University, Krakow (Poland)

    2017-11-07

    Active galactic nuclei (AGNs) are known to cover an extremely broad range of radio luminosities and the spread of their radio-loudness is very large at any value of the Eddington ratio. This implies very diverse jet production efficiencies which can result from the spread of the black hole spins and magnetic fluxes. Magnetic fluxes can be developed stochastically in the innermost zones of accretion discs, or can be advected to the central regions prior to the AGN phase. In the latter case there could be systematic differences between the properties of galaxies hosting radio-loud (RL) and radio-quiet (RQ) AGNs. In the former case the differences should be negligible for objects having the same Eddington ratio. To study the problem we decided to conduct a comparison study of host galaxy properties of RL and RQ AGNs. In this study we selected type II AGNs from SDSS spectroscopic catalogs. Our RL AGN sample consists of the AGNs appearing in the Best and Heckman (2012) catalog of radio galaxies. To compare RL and RQ galaxies that have the same AGN parameters we matched the galaxies in black hole mass, Eddington ratio and redshift. We compared several properties of the host galaxies in these two groups of objects like galaxy mass, color, concentration index, line widths, morphological type and interaction signatures. We found that in the studied group RL AGNs are preferentially hosted by elliptical galaxies while RQ ones are hosted by galaxies of later type. We also found that the fraction of interacting galaxies is the same in both groups of AGNs. These results suggest that the magnetic flux in RL AGNs is advected to the nucleus prior to the AGN phase.

  16. The use of Twitter´s Bio in radio programmes. From the profile´s presentation to the transmedia radio

    Directory of Open Access Journals (Sweden)

    Teresa PIÑEIRO OTERO

    2014-06-01

    Full Text Available The jump of conventional radio programs into social media has evolved in new spaces and interaction forms between radio broadcasters and radio listeners. Particularly, twitter community acquires a new dimension due to its public (non privacy status and shareability. From a transmedia perspective, this microblogging platform makes possible to the radio programs offering rich content (access to the tweets of radio show hosts or / and main collaborators, radio channel’s info... to the radio listeners. Although radio listeners can access those profiles on their own, or following real-time references of the program, it’s getting bigger the way radio show hosts use their profiles on twitter to improve synergies between multiple digital channels in order to increase the community engagement. Present article aims to analyze profile twitter bios of the bigger audience Spanish radio programs, in order to determine flow synergies between channels of the radio (brands and radio show hosts on twitter

  17. Radio frequency scanning tunneling spectroscopy for single-molecule spin resonance.

    Science.gov (United States)

    Müllegger, Stefan; Tebi, Stefano; Das, Amal K; Schöfberger, Wolfgang; Faschinger, Felix; Koch, Reinhold

    2014-09-26

    We probe nuclear and electron spins in a single molecule even beyond the electromagnetic dipole selection rules, at readily accessible magnetic fields (few mT) and temperatures (5 K) by resonant radio-frequency current from a scanning tunneling microscope. We achieve subnanometer spatial resolution combined with single-spin sensitivity, representing a 10 orders of magnitude improvement compared to existing magnetic resonance techniques. We demonstrate the successful resonant spectroscopy of the complete manifold of nuclear and electronic magnetic transitions of up to ΔI(z)=±3 and ΔJ(z)=±12 of single quantum spins in a single molecule. Our method of resonant radio-frequency scanning tunneling spectroscopy offers, atom-by-atom, unprecedented analytical power and spin control with an impact on diverse fields of nanoscience and nanotechnology.

  18. Compact radio sources

    International Nuclear Information System (INIS)

    Altschuler, D.R.

    1975-01-01

    Eighty-seven compact radio sources were monitored between 1971 and 1974 with the National Radio Astronomy Observatory interferometer. Both flux density and polarization were measured at intervals of about one month at wavelengths of 3.7 and 11.1 cms. Forty-four sources showed definite variability in their total and/or polarized flux density. The variations in polarization were of a shorter time scale than the corresponding flux density variations. Some of the qualitative features of an expanding source model were observed. The data suggest that some form of injection of relativistic electrons is taking place. The absence of significant depolarization in the variable sources indicates that only a small fraction of the mass of the radio outburst is in the form of non-relativistic plasma. Some of the objects observed belong to the BL-Lacertal class. It is shown that this class is very inhomogeneous in its radio properties. For the violently variable BL-Lacertal type objects the spectrum, flux variations and polarization data strongly suggest that these are very young objects

  19. First evidence of diffuse ultra-steep-spectrum radio emission surrounding the cool core of a cluster

    Science.gov (United States)

    Savini, F.; Bonafede, A.; Brüggen, M.; van Weeren, R.; Brunetti, G.; Intema, H.; Botteon, A.; Shimwell, T.; Wilber, A.; Rafferty, D.; Giacintucci, S.; Cassano, R.; Cuciti, V.; de Gasperin, F.; Röttgering, H.; Hoeft, M.; White, G.

    2018-05-01

    Diffuse synchrotron radio emission from cosmic-ray electrons is observed at the center of a number of galaxy clusters. These sources can be classified either as giant radio halos, which occur in merging clusters, or as mini halos, which are found only in cool-core clusters. In this paper, we present the first discovery of a cool-core cluster with an associated mini halo that also shows ultra-steep-spectrum emission extending well beyond the core that resembles radio halo emission. The large-scale component is discovered thanks to LOFAR observations at 144 MHz. We also analyse GMRT observations at 610 MHz to characterise the spectrum of the radio emission. An X-ray analysis reveals that the cluster is slightly disturbed, and we suggest that the steep-spectrum radio emission outside the core could be produced by a minor merger that powers electron re-acceleration without disrupting the cool core. This discovery suggests that, under particular circumstances, both a mini and giant halo could co-exist in a single cluster, opening new perspectives for particle acceleration mechanisms in galaxy clusters.

  20. 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...

  1. Radio images of the planets

    International Nuclear Information System (INIS)

    De Pater, I.

    1990-01-01

    Observations at radio wavelengths make possible detailed studies of planetary atmospheres, magnetospheres, and surface layers. The paper addresses the question of what can be learned from interferometric radio images of planets. Results from single-element radio observations are also discussed. Observations of both the terrestrial and the giant planets are considered. 106 refs

  2. Radio observations of symbiotic stars

    Energy Technology Data Exchange (ETDEWEB)

    Wright, A E [Commonwealth Scientific and Industrial Research Organization, Epping (Australia). Div. of Radiophysics; Allen, D A

    1978-09-01

    A search for 2-cm continuum emission from 91 symbiotic stars has been undertaken using the Parkes radio telescope. Nine sources have been detected, four of which are reported for the first time. The radio spectral indices are mostly about + 0.6; these are interpreted in terms of mass loss. In two stars a portion of the radio spectrum has an index of zero, and for one of these stars (RX Puppis) this is plausibly a manifestation of the cessation of symbiotic activity that occurred about two decades ago. There is an extraordinarily good correlation between the detectability at 2cm and the presence of circumstellar dust, but not between the radio and optical domains. The importance of continued radio monitoring of HM Sagittae over the next few years is stressed.

  3. 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.

  4. Spectral Energy Distribution and Radio Halo of NGC 253 at Low Radio Frequencies

    Energy Technology Data Exchange (ETDEWEB)

    Kapińska, A. D.; Staveley-Smith, L.; Meurer, G. R.; For, B.-Q. [International Centre for Radio Astronomy Research (ICRAR), University of Western Australia, 35 Stirling Hwy, WA 6009 (Australia); Crocker, R. [Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2611 (Australia); Bhandari, S.; Callingham, J. R.; Gaensler, B. M.; Hancock, P. J.; Lenc, E. [ARC Centre of Excellence for All-Sky Astrophysics (CAASTRO), Sydney NSW (Australia); Hurley-Walker, N.; Seymour, N. [International Centre for Radio Astronomy Research (ICRAR), Curtin University, Bentley, WA 6102 (Australia); Offringa, A. R. [Netherlands Institute for Radio Astronomy (ASTRON), P.O. Box 2, 7990 AA Dwingeloo (Netherlands); Hanish, D. J. [Spitzer Science Center, California Institute of Technology, MC 220-6, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Ekers, R. D.; Bell, M. E. [CSIRO Astronomy and Space Science (CASS), P.O. Box 76, Epping, NSW 1710 (Australia); Dwarakanath, K. S. [Raman Research Institute, Bangalore 560080 (India); Hindson, L. [Centre of Astrophysics Research, University of Hertfordshire, College Lane, Hatfield AL10 9AB (United Kingdom); Johnston-Hollitt, M. [School of Chemical and Physical Sciences, Victoria University of Wellington, P.O. Box 600, Wellington 6140 (New Zealand); McKinley, B., E-mail: anna.kapinska@uwa.edu.au [School of Physics, The University of Melbourne, Parkville, VIC 3010 (Australia); and others

    2017-03-20

    We present new radio continuum observations of NGC 253 from the Murchison Widefield Array at frequencies between 76 and 227 MHz. We model the broadband radio spectral energy distribution for the total flux density of NGC 253 between 76 MHz and 11 GHz. The spectrum is best described as a sum of a central starburst and extended emission. The central component, corresponding to the inner 500 pc of the starburst region of the galaxy, is best modeled as an internally free–free absorbed synchrotron plasma, with a turnover frequency around 230 MHz. The extended emission component of the spectrum of NGC 253 is best described as a synchrotron emission flattening at low radio frequencies. We find that 34% of the extended emission (outside the central starburst region) at 1 GHz becomes partially absorbed at low radio frequencies. Most of this flattening occurs in the western region of the southeast halo, and may be indicative of synchrotron self-absorption of shock-reaccelerated electrons or an intrinsic low-energy cutoff of the electron distribution. Furthermore, we detect the large-scale synchrotron radio halo of NGC 253 in our radio images. At 154–231 MHz the halo displays the well known X-shaped/horn-like structure, and extends out to ∼8 kpc in the z -direction (from the major axis).

  5. The radio recombination line spectrum of Orion A: Observations and analysis

    International Nuclear Information System (INIS)

    Lockman, F.J.; Brown, R.L.

    1975-01-01

    The entire body of radio observations of Orion A has been considered, and the means by which the temperature and density can be derived from the ratio T/subL//T/subC/ and the line width Δv of the hydrogen radio recombination lines is examined. Since it is critical to determine the extent to which low-frequency line measurements are contaminated by ''baseline-subtraction'' problems, new observations are presented which, together with general considerations of the line shape and data reduction processes, support the following conclusions: T/subL//T/subC/ and Δv can be accurately determined in the low-frequency observations even when erroneous baselines are removed; in accord with other studies, a density gradient must exist in the nebula; isothermal models cannot reproduce the observed line strenghts; the most dense parts of the nebula must be somewhat cooler than the surrounding gas. A model of Orion A has been constructed that is derived directly from the radio continuum observations. These observations demand that the simplest possible model of the nebula be comprised of three regions whose gross properties: the electrons density and the size: are defined by the continuum measurements. This model has been used for an analysis of the radio recombination line data, and virtually all known radio data on the Orion Nebula including Δv and T/subL//T/subC/ of the H nα lines from 610 MHz to 85 GHz Δv and T/subL//T/subC/ of all the observed H nβ lines; the shape and magnitude of the radio continuum spectrum can be reproduced. The application of this model to the problem of the abundance and distribution of ionized helium with the nebula is also considered

  6. Morphological Evolution in High-Redshift Radio Galaxies and the Formation of Giant Elliptical Galaxies

    International Nuclear Information System (INIS)

    Breugel, W.J. van; Stanford, S.A.; Spinrad, H.; Stern, D.; Graham, J.R.

    1998-01-01

    We present deep near-infrared images of high-redshift radio galaxies (HzRGs) obtained with the near-infrared camera (NIRC) on the Keck I telescope. In most cases, the near-IR data sample rest wavelengths that are free of contamination from strong emission lines and at λ rest > 4000 Angstrom, where older stellar populations, if present, might dominate the observed flux. At z > 3, the rest-frame optical morphologies generally have faint, large-scale (∼50 kpc) emission surrounding multiple, ∼10 kpc components. The brightest of these components are often aligned with the radio structures. These morphologies change dramatically at 2 rest ) ∼ -20 to -22] of the individual components in the z > 3 HzRGs are similar to the total sizes and luminosities of normal radio-quiet star forming galaxies at z = 3 - 4. For objects where such data are available, our observations show that the line-free, near-IR colors of the z > 3 galaxies are very blue, consistent with models in which recent star formation dominates the observed light. Direct spectroscopic evidence for massive star formation in one of the z > 3 HzRGs exists (4C 41.17). Our results suggest that the z > 3 HzRGs evolve into much more massive systems than the radio-quiet galaxies and that they are qualitatively consistent with models in which massive galaxies form in hierarchical fashion through the merging of smaller star-forming systems. The presence of relatively luminous subcomponents along the radio axes of the z > 3 galaxies suggests a causal connection with the AGN. We compare the radio and near-IR sizes as a function of redshift and suggest that this parameter may be a measure of the degree to which the radio sources have induced star formation in the parent objects. We also discuss the Hubble diagram of radio galaxies, the possibility of a radio power dependence in the K-z relation, and its implications for radio galaxy formation. Finally, we present for the first time in published format basic radio and

  7. THE ABSENCE OF RADIO EMISSION FROM THE GLOBULAR CLUSTER G1

    Energy Technology Data Exchange (ETDEWEB)

    Miller-Jones, J. C. A. [International Centre for Radio Astronomy Research, Curtin University, GPO Box U1987, Perth, WA 6845 (Australia); Wrobel, J. M. [NRAO Domenici Science Operations Center, 1003 Lopezville Road, Socorro, NM 87801 (United States); Sivakoff, G. R.; Heinke, C. O.; Miller, R. E. [Department of Physics, University of Alberta, Room 238 CEB, Edmonton, AB T6G 2G7 (Canada); Plotkin, R. M. [Astronomical Institute ' Anton Pannekoek' , University of Amsterdam, Science Park 904, 1098 XH Amsterdam (Netherlands); Di Stefano, R. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Greene, J. E. [Department of Astronomy, University of Texas at Austin, 1 University Station C1400, Austin, TX 71712 (United States); Ho, L. C. [The Observatories of the Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Joseph, T. D.; Maccarone, T. J. [School of Physics and Astronomy, University of Southampton, Highfield SO17 IBJ (United Kingdom); Kong, A. K. H., E-mail: james.miller-jones@curtin.edu.au [Institute of Astronomy and Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China)

    2012-08-10

    The detections of both X-ray and radio emission from the cluster G1 in M31 have provided strong support for existing dynamical evidence for an intermediate-mass black hole (IMBH) of mass (1.8 {+-} 0.5) Multiplication-Sign 10{sup 4} M{sub Sun} at the cluster center. However, given the relatively low significance and astrometric accuracy of the radio detection, and the non-simultaneity of the X-ray and radio measurements, this identification required further confirmation. Here we present deep, high angular resolution, strictly simultaneous X-ray and radio observations of G1. While the X-ray emission (L{sub X} = 1.74{sup +0.53}{sub -0.44} Multiplication-Sign 10{sup 36} (d/750 kpc){sup 2} erg s{sup -1} in the 0.5-10 keV band) remained fully consistent with previous observations, we detected no radio emission from the cluster center down to a 3{sigma} upper limit of 4.7 {mu}Jy beam{sup -1}. Our favored explanation for the previous radio detection is flaring activity from a black hole low-mass X-ray binary (LMXB). We performed a new regression of the 'Fundamental Plane' of black hole activity, valid for determining black hole mass from radio and X-ray observations of sub-Eddington black holes, finding log M{sub BH} = (1.638 {+-} 0.070)log L{sub R} - (1.136 {+-} 0.077)log L{sub X} - (6.863 {+-} 0.790), with an empirically determined uncertainty of 0.44 dex. This constrains the mass of the X-ray source in G1, if a black hole, to be <9.7 Multiplication-Sign 10{sup 3} M{sub Sun} at 95% confidence, suggesting that it is a persistent LMXB. This annuls what was previously the most convincing evidence from radiation for an IMBH in the Local Group, though the evidence for an IMBH in G1 from velocity dispersion measurements remains unaffected by these results.

  8. A Radio-Frequency-over-Fiber link for large-array radio astronomy applications

    International Nuclear Information System (INIS)

    Mena, J; Bandura, K; Cliche, J-F; Dobbs, M; Gilbert, A; Tang, Q Y

    2013-01-01

    A prototype 425-850 MHz Radio-Frequency-over-Fiber (RFoF) link for the Canadian Hydrogen Intensity Mapping Experiment (CHIME) is presented. The design is based on a directly modulated Fabry-Perot (FP) laser, operating at ambient temperature, and a single-mode fiber. The dynamic performance, gain stability, and phase stability of the RFoF link are characterized. Tests on a two-element interferometer built at the Dominion Radio Astrophysical Observatory for CHIME prototyping demonstrate that RFoF can be successfully used as a cost-effective solution for analog signal transport on the CHIME telescope and other large-array radio astronomy applications

  9. RADIO VARIABILITY IN SEYFERT NUCLEI

    International Nuclear Information System (INIS)

    Mundell, C. G.; Ferruit, P.; Nagar, N.; Wilson, A. S.

    2009-01-01

    Comparison of 8.4 GHz radio images of a sample of eleven, early-type Seyfert galaxies with previous observations reveals possible variation in the nuclear radio flux density in five of them over a seven year period. Four Seyferts (NGC 2110, NGC 3081, MCG -6-30-15, and NGC 5273) show a decline in their 8.4 GHz nuclear flux density between 1992 and 1999, while one (NGC 4117) shows an increase; the flux densities of the remaining six Seyferts (Mrk 607, NGC 1386, Mrk 620, NGC 3516, NGC 4968, and NGC 7465) have remained constant over this period. New images of MCG -5-23-16 are also presented. We find no correlation between radio variability and nuclear radio luminosity or Seyfert nuclear type, although the sample is small and dominated by type 2 Seyferts. Instead, a possible correlation between the presence of nuclear radio variability and the absence of hundred parsec-scale radio emission is seen, with four out of five marginally resolved or unresolved nuclei showing a change in nuclear flux density, while five out of six extended sources show no nuclear variability despite having unresolved nuclear sources. NGC 2110 is the only source in our sample with significant extended radio structure and strong nuclear variability (∼38% decline in nuclear flux density over seven years). The observed nuclear flux variability indicates significant changes are likely to have occurred in the structure of the nucleus on scales smaller than the VLA beam size (i.e., within the central ∼0.''1 (15 pc)), between the two epochs, possibly due to the appearance and fading of new components or shocks in the jet, consistent with previous detection of subparsec-scale nuclear structure in this Seyfert. Our results suggest that all Seyferts may exhibit variation in their nuclear radio flux density at 8.4 GHz, but that variability is more easily recognized in compact sources in which emission from the variable nucleus is not diluted by unresolved, constant flux density radio jet emission

  10. Characteristics of shock-associated fast-drift kilometric radio bursts

    Science.gov (United States)

    Macdowall, R. J.; Kundu, M. R.; Stone, R. G.

    1987-01-01

    The existence of a class of fast-drift, shock-associated (SA), kilometric radio bursts which occur at the time of metric type II emission and which are not entirely the kilometric continuation of metric type III bursts has been reported previously (Cane et al., 1981). In this paper unambiguous SA event criteria are established for the purpose of statistically comparing SA events with conventional kilometric type III bursts. Applying these criteria to all long-duration, fast-drift bursts observed by the ISEE-3 spacecraft during a 28-month interval, it is found that more than 70 percent of the events satisfying the criteria are associated with the radio signatures of coronal shocks. If a given event is associated with a metric type II or type IV burst, it is 13 times more likely to satisfy the SA criteria than an event associated only with metric type III activity.

  11. Perancangan Radio Streaming Edukasi (Studi Kasus Balai Pengembangan Media Radio YOGYAKARTA)

    OpenAIRE

    Nurwulan, Ayu Isni; Paputungan, Irving Vitra

    2009-01-01

    Pendidikan berkualitas sudah sewajarnya bisa dinikmati secara merata oleh semua orang. Mediapembelajaran secara audio yang selama ini disampaikan masih memiliki banyak keterbatasan, terutama padalingkup wilayah penyampaian. Dalam makalah ini, sebuah media pendidikan berbasis audio dengan cara laindiusulkan. Media tersebut bernama radio streaming. Pembuatan radio streaming memerlukan banyak analisissehingga perancangannya tepat. Hasil analisis dan perancangan yang disampaikan dalam makalah ini...

  12. Structure in radio galaxies

    International Nuclear Information System (INIS)

    Breugel, W. van.

    1980-01-01

    It is shown that radio jets are a rather common phenomenon in radio galaxies. Jets can be disguised as trails in head-tail sources, bridges in double sources or simply remain undetected because of lack of resolution and sensitivity. It is natural to associate these jets with the channels which had previously been suggested to supply energy to the extended radio lobes. The observations of optical emission suggest that a continuous non-thermal spectrum extending from 10 9 to 10 15 Hz is a common property of jets. Because significant amounts of interstellar matter are also observed in each of the galaxies surveyed it seems that models for jets which involve an interaction with this medium may be most appropriate. New information about the overall structure of extended radio sources has been obtained from the detailed multifrequency study with the WSRT. (Auth.)

  13. Music, radio and mediatization

    DEFF Research Database (Denmark)

    Michelsen, Morten; Krogh, Mads

    2016-01-01

    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 nonlinearity of concrete processes of mediatization as they take place in the multiple meetings between a decentred notion of radio and musical life.......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...

  14. Radio emission from Supernovae and High Precision Astrometry

    Science.gov (United States)

    Perez-Torres, M. A.

    1999-11-01

    -similarly and spherically symmetric expanding, and that the radio emission comes only from its shell. We take into account radiative losses due to synchrotron emission and losses due to the supernova expansion. Although relatively simple, the model retains the main physical features involving the process of radio emission. Our code, MOSES (MOdeling of Synchrotron Emissiom from Supernovae), reproduces fairly well the radio light curves for SN 1993J obtained from single dish measurements. Constrained by our VLBI measurements, we fitted the light curves of the supernova by adjusting five parameters, namely: index of the injected distribution of relativistic electrons, p; ratio of the mass-loss rate to the wind velocity of the supernova progenitor, M_w; and the initial values for the injection of electrons, N_0, the low-energy cut-off of the relativistic electrons, emin, and the magnetic field, B_0. To get a reasonable fit, we need: values of the spectral index, p, very close to three; a wind parameter M_w approx 1.7, thus indicating the existence of a strong presupernova wind ( 8.5*10^{-5} solar masses per year); low initial values of N_0 ( 7 * 10^{-7} erg^{p-1} cm^3); initially high low-energy cut-offs of the relativistic electrons (Erel approx. 90 m_e*c^2); and high initial magnetic fields (B_0 approx. 30 Gauss). An uncertainty of about a factor 2 is likely to exist for such parameters as B_0, N_0, and E_min. In contrast, both p and M_w seem to be well constrained to their nominal values. We stress that the large magnetic field required represents a relatively shocking result in view of the usually small (a few microgauss) interstellar magnetic fields, and tends to favor theories in which the magnetic field is amplified in situ by turbulences inside the supernova shell.

  15. 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

  16. The comparative cost-effectiveness of colorectal cancer screening using faecal immunochemical test vs. colonoscopy.

    Science.gov (United States)

    Wong, Martin C S; Ching, Jessica Y L; Chan, Victor C W; Sung, Joseph J Y

    2015-09-04

    Faecal immunochemical tests (FITs) and colonoscopy are two common screening tools for colorectal cancer(CRC). Most cost-effectiveness studies focused on survival as the outcome, and were based on modeling techniques instead of real world observational data. This study evaluated the cost-effectiveness of these two tests to detect colorectal neoplastic lesions based on data from a 5-year community screening service. The incremental cost-effectiveness ratio (ICER) was assessed based on the detection rates of neoplastic lesions, and costs including screening compliance, polypectomy, colonoscopy complications, and staging of CRC detected. A total of 5,863 patients received yearly FIT and 4,869 received colonoscopy. Compared with FIT, colonoscopy detected notably more adenomas (23.6% vs. 1.6%) and advanced lesions or cancer (4.2% vs. 1.2%). Using FIT as control, the ICER of screening colonoscopy in detecting adenoma, advanced adenoma, CRC and a composite endpoint of either advanced adenoma or stage I CRC was US$3,489, US$27,962, US$922,762 and US$23,981 respectively. The respective ICER was US$3,597, US$439,513, -US$2,765,876 and US$32,297 among lower-risk subjects; whilst the corresponding figure was US$3,153, US$14,852, US$184,162 and US$13,919 among higher-risk subjects. When compared to FIT, colonoscopy is considered cost-effective for screening adenoma, advanced neoplasia, and a composite endpoint of advanced neoplasia or stage I CRC.

  17. 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

  18. OPTICAL SPECTRA OF CANDIDATE INTERNATIONAL CELESTIAL REFERENCE FRAME (ICRF) FLAT-SPECTRUM RADIO SOURCES

    Energy Technology Data Exchange (ETDEWEB)

    Titov, O.; Stanford, Laura M. [Geoscience Australia, P.O. Box 378, Canberra, ACT 2601 (Australia); Johnston, Helen M.; Hunstead, Richard W. [Sydney Institute for Astronomy, School of Physics, University of Sydney, NSW 2006 (Australia); Pursimo, T. [Nordic Optical Telescope, Nordic Optical Telescope Apartado 474E-38700 Santa Cruz de La Palma, Santa Cruz de Tenerife (Spain); Jauncey, David L. [CSIRO Astronomy and Space Science, ATNF and Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2611 (Australia); Maslennikov, K. [Central Astronomical Observatory at Pulkovo, Pulkovskoye Shosse, 65/1, 196140, St. Petersburg (Russian Federation); Boldycheva, A., E-mail: oleg.titov@ga.gov.au [Ioffe Physical Technical Institute, 26 Polytekhnicheskaya, St. Petersburg, 194021 (Russian Federation)

    2013-07-01

    Continuing our program of spectroscopic observations of International Celestial Reference Frame (ICRF) sources, we present redshifts for 120 quasars and radio galaxies. Data were obtained with five telescopes: the 3.58 m European Southern Observatory New Technology Telescope, the two 8.2 m Gemini telescopes, the 2.5 m Nordic Optical Telescope (NOT), and the 6.0 m Big Azimuthal Telescope of the Special Astrophysical Observatory in Russia. The targets were selected from the International VLBI Service for Geodesy and Astrometry candidate International Celestial Reference Catalog which forms part of an observational very long baseline interferometry (VLBI) program to strengthen the celestial reference frame. We obtained spectra of the potential optical counterparts of more than 150 compact flat-spectrum radio sources, and measured redshifts of 120 emission-line objects, together with 19 BL Lac objects. These identifications add significantly to the precise radio-optical frame tie to be undertaken by Gaia, due to be launched in 2013, and to the existing data available for analyzing source proper motions over the celestial sphere. We show that the distribution of redshifts for ICRF sources is consistent with the much larger sample drawn from Faint Images of the Radio Sky at Twenty cm (FIRST) and Sloan Digital Sky Survey, implying that the ultra-compact VLBI sources are not distinguished from the overall radio-loud quasar population. In addition, we obtained NOT spectra for five radio sources from the FIRST and NRAO VLA Sky Survey catalogs, selected on the basis of their red colors, which yielded three quasars with z > 4.

  19. The effect of solar radio bursts on the GNSS radio occultation signals

    Science.gov (United States)

    Yue, Xinan; Schreiner, William S.; Kuo, Ying-Hwa; Zhao, Biqiang; Wan, Weixing; Ren, Zhipeng; Liu, Libo; Wei, Yong; Lei, Jiuhou; Solomon, Stan; Rocken, Christian

    2013-09-01

    radio burst (SRB) is the radio wave emission after a solar flare, covering a broad frequency range, originated from the Sun's atmosphere. During the SRB occurrence, some specific frequency radio wave could interfere with the Global Navigation Satellite System (GNSS) signals and therefore disturb the received signals. In this study, the low Earth orbit- (LEO-) based high-resolution GNSS radio occultation (RO) signals from multiple satellites (COSMIC, CHAMP, GRACE, SAC-C, Metop-A, and TerraSAR-X) processed in University Corporation for Atmospheric Research (UCAR) were first used to evaluate the effect of SRB on the RO technique. The radio solar telescope network (RSTN) observed radio flux was used to represent SRB occurrence. An extreme case during 6 December 2006 and statistical analysis during April 2006 to September 2012 were studied. The LEO RO signals show frequent loss of lock (LOL), simultaneous decrease on L1 and L2 signal-to-noise ratio (SNR) globally during daytime, small-scale perturbations of SNR, and decreased successful retrieval percentage (SRP) for both ionospheric and atmospheric occultations during SRB occurrence. A potential harmonic band interference was identified. Either decreased data volume or data quality will influence weather prediction, climate study, and space weather monitoring by using RO data during SRB time. Statistically, the SRP of ionospheric and atmospheric occultation retrieval shows ~4% and ~13% decrease, respectively, while the SNR of L1 and L2 show ~5.7% and ~11.7% decrease, respectively. A threshold value of ~1807 SFU of 1415 MHz frequency, which can result in observable GNSS SNR decrease, was derived based on our statistical analysis.

  20. Radio Galaxy Zoo: Machine learning for radio source host galaxy cross-identification

    Science.gov (United States)

    Alger, M. J.; Banfield, J. K.; Ong, C. S.; Rudnick, L.; Wong, O. I.; Wolf, C.; Andernach, H.; Norris, R. P.; Shabala, S. S.

    2018-05-01

    We consider the problem of determining the host galaxies of radio sources by cross-identification. This has traditionally been done manually, which will be intractable for wide-area radio surveys like the Evolutionary Map of the Universe (EMU). Automated cross-identification will be critical for these future surveys, and machine learning may provide the tools to develop such methods. We apply a standard approach from computer vision to cross-identification, introducing one possible way of automating this problem, and explore the pros and cons of this approach. We apply our method to the 1.4 GHz Australian Telescope Large Area Survey (ATLAS) observations of the Chandra Deep Field South (CDFS) and the ESO Large Area ISO Survey South 1 (ELAIS-S1) fields by cross-identifying them with the Spitzer Wide-area Infrared Extragalactic (SWIRE) survey. We train our method with two sets of data: expert cross-identifications of CDFS from the initial ATLAS data release and crowdsourced cross-identifications of CDFS from Radio Galaxy Zoo. We found that a simple strategy of cross-identifying a radio component with the nearest galaxy performs comparably to our more complex methods, though our estimated best-case performance is near 100 per cent. ATLAS contains 87 complex radio sources that have been cross-identified by experts, so there are not enough complex examples to learn how to cross-identify them accurately. Much larger datasets are therefore required for training methods like ours. We also show that training our method on Radio Galaxy Zoo cross-identifications gives comparable results to training on expert cross-identifications, demonstrating the value of crowdsourced training data.

  1. Radio-quiet Gamma-ray Pulsars

    Directory of Open Access Journals (Sweden)

    Lupin Chun-Che Lin

    2016-09-01

    Full Text Available 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 to specified discuss their common and specific features.

  2. The Origin of Powerful Radio Sources

    Science.gov (United States)

    Wilson, A. S.; Colbert, E. J. M.

    1995-05-01

    Radio-loud active galaxies are associated with elliptical or elliptical-like galaxies, many of which appear to be the result of a recent merger. In contrast, radio-quiet active galaxies prefer spiral hosts. Despite the very large difference in radio luminosities between the two classes, their continua and line spectra from infrared through X-ray frequencies are very similar. In this paper, we describe recent developments of our model (Ap. J. 438, 62 1995) in which the radio-loud phenomenon is the result of a merger of two galaxies, with each galaxy nucleus containing a slowly (or non-) rotating supermassive black hole. It is envisaged that the two black holes eventually coalesce. For the small fraction of mergers in which the two holes are both massive and of comparable mass, a rapidly-spinning, high-mass hole results. The spin energy of a rapidly rotating 10(8-9) solar mass hole suffices to provide the ~ 10(60) ergs in relativistic particles and magnetic fields in the most energetic radio sources. Luminous radio-quiet active galaxies contain high-mass, slowly-rotating holes, with the infrared through X-ray emission of both classes being fuelled by accretion as commonly assumed. We discuss constraints on the model from the luminosity functions of radio-loud and radio-quiet galaxies and from the known cosmological evolution of the radio source population; this evolution is assumed to reflect higher galaxy merger rates in the past.

  3. ¿Radios ciudadanas?

    OpenAIRE

    López Vigil, José Ignacio

    1998-01-01

    Educativas, sindicales, populares, comunitarias, libres, rebeldes, participativas, alternativas, alterativas, han sido las denominaciones de la radio cuando su proyecto está al servicio de la gente. Palabras apropiadas y nobles -dice elautor-pero devaluadas, a las que ahora se agrega la radio ciudadana, para relievarla como ejercicio depoder y espacio de verdadera participación de la genteenla vida de su nación.

  4. 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.

  5. Radio Frequency Energy Harvesting for Long Lifetime Wireless Sensor Networks

    DEFF Research Database (Denmark)

    Han, Bo; Nielsen, Rasmus Hjorth; Prasad, Ramjee

    2014-01-01

    In wireless sensor networks energy scarcity is a major concern on energy consumption, and by properly designing on the node network architecture or selecting efficient protocols of the networks, the maximum energy can be reduced significantly thereby increasing the network lifetime. However......, in most of the cases, the sensor nodes are either powered by non-replaceable batteries, or there will be a considerable replacement cost. Thus a self-rechargeable sensor node design is necessary: the sensor node should be able to harvest energy from the environment. Among the existing techniques......, harvesting energy from the radio frequency (RF) waves gives the lowest system design. Previous research on RF energy harvesting is based on the model that the radio energy is omnidirectional in the air. In this paper, a directional transmission/receiving model is proposed which can further overcome the path...

  6. GRAVITATIONAL-WAVE CONSTRAINTS ON THE PROGENITORS OF FAST RADIO BURSTS

    International Nuclear Information System (INIS)

    Callister, Thomas; Kanner, Jonah; Weinstein, Alan

    2016-01-01

    The nature of fast radio bursts (FRBs) remains enigmatic. Highly energetic radio pulses of millisecond duration, FRBs are observed with dispersion measures consistent with an extragalactic source. A variety of models have been proposed to explain their origin. One popular class of theorized FRB progenitor is the coalescence of compact binaries composed of neutron stars and/or black holes. Such coalescence events are strong gravitational-wave emitters. We demonstrate that measurements made by the LIGO and Virgo gravitational-wave observatories can be leveraged to severely constrain the validity of FRB binary coalescence models. Existing measurements constrain the binary black hole rate to approximately 5% of the FRB rate, and results from Advanced LIGO’s O1 and O2 observing runs may place similarly strong constraints on the fraction of FRBs due to binary neutron star and neutron star–black hole progenitors.

  7. The Hartebeeshoek Radio Astronomy Observatory

    International Nuclear Information System (INIS)

    Nicolson, G.D.

    1986-01-01

    This article briefly discusses the questions, problems and study fields of the modern astronomer. Radioastronomy has made important contributions to the study of the evolution of stars and has given much information on the birth of stars while at the other extreme, studies of neutron stars and the radio emission from the remnants of supernova explosions have given further insight into the death of individual stars. Radio astronomical studies have learned astronomers much about the structure of the Milky way and some twenty years ago, in a search for new radio galaxies, quasars were discovered. Radioastronomy research in South Africa is carried out at the Hartebeesthoek Radio Astronomy Observatory

  8. Future Cosmological Constraints From Fast Radio Bursts

    Science.gov (United States)

    Walters, Anthony; Weltman, Amanda; Gaensler, B. M.; Ma, Yin-Zhe; Witzemann, Amadeus

    2018-03-01

    We consider the possible observation of fast radio bursts (FRBs) with planned future radio telescopes, and investigate how well the dispersions and redshifts of these signals might constrain cosmological parameters. We construct mock catalogs of FRB dispersion measure (DM) data and employ Markov Chain Monte Carlo analysis, with which we forecast and compare with existing constraints in the flat ΛCDM model, as well as some popular extensions that include dark energy equation of state and curvature parameters. We find that the scatter in DM observations caused by inhomogeneities in the intergalactic medium (IGM) poses a big challenge to the utility of FRBs as a cosmic probe. Only in the most optimistic case, with a high number of events and low IGM variance, do FRBs aid in improving current constraints. In particular, when FRBs are combined with CMB+BAO+SNe+H 0 data, we find the biggest improvement comes in the {{{Ω }}}{{b}}{h}2 constraint. Also, we find that the dark energy equation of state is poorly constrained, while the constraint on the curvature parameter, Ω k , shows some improvement when combined with current constraints. When FRBs are combined with future baryon acoustic oscillation (BAO) data from 21 cm Intensity Mapping, we find little improvement over the constraints from BAOs alone. However, the inclusion of FRBs introduces an additional parameter constraint, {{{Ω }}}{{b}}{h}2, which turns out to be comparable to existing constraints. This suggests that FRBs provide valuable information about the cosmological baryon density in the intermediate redshift universe, independent of high-redshift CMB data.

  9. Radio investigations of clusters of galaxies

    International Nuclear Information System (INIS)

    Valentijn, E.A.

    1978-01-01

    This thesis contains a number of papers of the series entitled, A Westerbork Survey of Rich Clusters of Galaxies. The primary aim was to study the radio characteristics of cluster galaxies and especially the question whether their ''radio-activity'' is influenced by their location inside a cluster. It is enquired whether the presence of an intra-cluster medium (ICM), or the typical cluster evolution or cluster dynamical processes can give rise to radio-observable effects on the behaviour of cluster galaxies. 610 MHz WSRT observations of the Coma cluster (and radio observations of the Hercules supercluster) are presented. Extended radio sources in Abell clusters are then described. (Auth.)

  10. Titration of digoxin through radio-immunology in the solid phase

    International Nuclear Information System (INIS)

    Hersh, L.S.; Yaverbaum, Sidney.

    1975-01-01

    The invention relates to biological titrations. It refers to a method for determining the digoxin concentration in a solution, characterized in that it comprises the steps of: causing the solution (a known amount of labelled digoxin and a composite substance constituted by anti-digoxin antibodies chemically coupled through the medium of a silane coupling agent) to react with magnetically-sensitive inorganic particles, so as to generate immuno-chemical complex; magnetically separating the composite substance from the reaction solution; measuring the radioactivity of the thus separated composite substance or of the remaining solution; and comparing the measurements of step with a reference curve so as to determine the digoxin concentration [fr

  11. Comparison of VLBI radio core and X-ray flux densities of extragalactic radio sources

    International Nuclear Information System (INIS)

    Bloom, S.D.; Marscher, A.P.

    1990-01-01

    The Einstein Observatory revealed that most quasars, selected in a variety of ways, are strong x-ray emitters. Radio bright quasars are statistically more luminous in the x-ray than their radio-quiet counterparts. It was also found that the 90 GHz to soft x-ray spectral index has a very small dispersion for sources selected by their strong millimeter emission. This implies a close relationship between compact radio flux density and x-ray emission. Strong correlations have been found between the arcsecond scale flux densities and soft x-ray fluxes. It is suggested that the correlation can be explained if the soft x-rays were produced by the synchrotron self-Compton (SSC) process within the compact radio emitting region. (author)

  12. Characteristics of adenomas detected by fecal immunochemical test in colorectal cancer screening.

    Science.gov (United States)

    Cubiella, Joaquín; Castro, Inés; Hernandez, Vicent; González-Mao, Carmen; Rivera, Concepción; Iglesias, Felipe; Cid, Lucía; Soto, Santiago; de-Castro, Luisa; Vega, Pablo; Hermo, Jose Antonio; Macenlle, Ramiro; Martínez, Alfonso; Martínez-Ares, David; Estevez, Pamela; Cid, Estela; Herreros-Villanueva, Marta; Portillo, Isabel; Bujanda, Luis; Fernández-Seara, Javier

    2014-09-01

    Fecal immunochemical test (FIT) diagnostic accuracy for colorectal adenoma detection in colorectal cancer screening is limited. We analyzed 474 asymptomatic subjects with adenomas detected on colonoscopy in two blinded diagnostic tests studies designed to assess FIT diagnostic accuracy. We determined the characteristics of adenomas (number, size, histology, morphology, and location) and the risk of metachronous lesions (according to European guidelines). Finally, we performed a logistic regression to identify those variables independently associated with a positive result. Advanced adenomas were found in 145 patients (75.6% distal and 24.3% only proximal to splenic flexure). Patients were classified as low (59.5%), intermediate (30.2%), and high risk (10.3%) according to European guidelines. At a 100-ng/mL threshold, FIT was positive in 61 patients (12.8%). Patients with advanced adenomas [odds ratio (OR), 8.8; 95% confidence interval (CI), 4.76-16.25], distal advanced adenomas (OR, 6.7; 95% CI, 1.9-8.8), high risk (OR, 20.1; 95% CI, 8.8-45.8), or intermediate risk lesions (OR, 6; 95% CI, 2.9-12.4) had more probabilities to have a positive test. The characteristics of adenomas independently associated were number of adenomas (OR, 1.22; 95% CI, 1.04-1.42), distal flat adenomas (OR, 0.44; 95% CI, 0.21-0.96), pedunculated adenomas (OR, 2.28; 95% CI, 1.48-3.5), and maximum size of distal adenomas (mm; OR, 1.24; 95% CI, 1.16-1.32). European guidelines classification and adenoma location correlates with the likelihood of a positive FIT result. This information allows us to understand the FIT impact in colorectal cancer prevention. Likewise, it should be taken into account in the development of new colorectal adenomas biomarkers. ©2014 American Association for Cancer Research.

  13. 2nd Radio and Antenna Days of the Indian Ocean (RADIO 2014)

    Science.gov (United States)

    2014-10-01

    It was an honor and a great pleasure for all those involved in its organization to welcome the participants to the ''Radio and Antenna Days of the Indian Ocean'' (RADIO 2014) international conference that was held from 7th to 10th April 2014 at the Sugar Beach Resort, Wolmar, Flic-en-Flac, Mauritius. RADIO 2014 is the second of a series of conferences organized in the Indian Ocean region. The aim of the conference is to discuss recent developments, theories and practical applications covering the whole scope of radio-frequency engineering, including radio waves, antennas, propagation, and electromagnetic compatibility. The RADIO international conference emerged following discussions with engineers and scientists from the countries of the Indian Ocean as well as from other parts of the world and a need was felt for the organization of such an event in this region. Following numerous requests, the Island of Mauritius, worldwide known for its white sandy beaches and pleasant tropical atmosphere, was again chosen for the organization of the 2nd RADIO international conference. The conference was organized by the Radio Society, Mauritius and the Local Organizing Committee consisted of scientists from SUPELEC, France, the University of Mauritius, and the University of Technology, Mauritius. We would like to take the opportunity to thank all people, institutions and companies that made the event such a success. We are grateful to our gold sponsors CST and FEKO as well as URSI for their generous support which enabled us to partially support one PhD student and two scientists to attend the conference. We would also like to thank IEEE-APS and URSI for providing technical co-sponsorship. More than hundred and thirty abstracts were submitted to the conference. They were peer-reviewed by an international scientific committee and, based on the reviews, either accepted, eventually after revision, or rejected. RADIO 2014 brought together participants from twenty countries spanning

  14. Effectiveness of radio spokesperson's gender, vocal pitch and accent and the use of music in radio advertising

    Directory of Open Access Journals (Sweden)

    Josefa D. Martín-Santana

    2015-07-01

    Full Text Available The aim of this study is to analyze how certain voice features of radio spokespersons and background music influence the advertising effectiveness of a radio spot from the cognitive, affective and conative perspectives. We used a 2 × 2 × 2 × 2 experimental design in 16 different radio programs in which an ad hoc radio spot was inserted during advertising block. This ad changed according to combinations of spokesperson's gender (male–female, vocal pitch (low–high and accent (local–standard. In addition to these independent factors, the effect of background music in advertisements was also tested and compared with those that only had words. 987 regular radio listeners comprised the sample that was exposed to the radio program we created. Based on the differences in the levels of effectiveness in the tested voice features, our results suggest that the choice of the voice in radio advertising is one of the most important decisions an advertiser faces. Furthermore, the findings show that the inclusion of music does not always imply greater effectiveness.

  15. Planck Early Results. XV. Spectral Energy Distributions and Radio Continuum Spectra of Northern Extragalactic Radio Sources

    Science.gov (United States)

    Aatrokoski, J.; Ade, P. A. R.; Aghanim, N.; Aller, H. D.; Aller, M. F.; Angelakis, E.; Amaud, M.; Ashdown, M.; Aumont, J.; Baccigalupi, C.; hide

    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 multi frequency 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, shape the radio spectra as they move in the relativistic jet. 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 modelling of the synchrotron bump using multiple components. Planck ERCSC data also suggest that the original accelerated electron energy spectrum could be much harder than commonly thought, with power-law index around 1.5 instead of the canonical 2.5. The implications of this are discussed for the acceleration mechanisms effective in blazar shock. Furthermore in many cases the Planck data indicate that gamma-ray emission must originate in the same shocks that produce the radio emission.

  16. 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

  17. Perkembangan dan Problematika Radio Komunitas di Indonesia

    Directory of Open Access Journals (Sweden)

    Masduki .

    2013-12-01

    Full Text Available Abstract: This article is about the development of community radio in Indonesia, it is problems and solutions. Community radio in Indonesia developed as an alternative to both public radio and commercial radio after the fall of Soeharto in 1998. Two important features of community radio are that it provides all community members with equal access to information, enhancing their rights and obligations, access to justice, public accountability and also enables them to participate actively in radio management and production. Both features enhance people’s selfawareness and sense of belonging to a community. The expansion of the progressive, participatory, community ownership, and non-profit model of community radio, has become a third sector of communication beside the commercial or state media. The dynamic development of community radio in Indonesia faced several problems starting from it is definition, implementation of regulation until standards of programmes operation based on the concept of community approach and participation

  18. The detectability of radio emission from exoplanets

    Science.gov (United States)

    Lynch, C. R.; Murphy, Tara; Lenc, E.; Kaplan, D. L.

    2018-05-01

    Like the magnetised planets in our Solar System, magnetised exoplanets should emit strongly at radio wavelengths. Radio emission directly traces the planetary magnetic fields and radio detections can place constraints on the physical parameters of these features. Large comparative studies of predicted radio emission characteristics for the known population of exoplanets help to identify what physical parameters could be key for producing bright, observable radio emission. Since the last comparative study, many thousands of exoplanets have been discovered. We report new estimates for the radio flux densities and maximum emission frequencies for the current population of known exoplanets orbiting pre-main sequence and main-sequence stars with spectral types F-M. The set of exoplanets predicted to produce observable radio emission are Hot Jupiters orbiting young stars. The youth of these system predicts strong stellar magnetic fields and/or dense winds, which are key for producing bright, observable radio emission. We use a new all-sky circular polarisation Murchison Widefield Array survey to place sensitive limits on 200 MHz emission from exoplanets, with 3σ values ranging from 4.0 - 45.0 mJy. Using a targeted Giant Metre Wave Radio Telescope observing campaign, we also report a 3σ upper limit of 4.5 mJy on the radio emission from V830 Tau b, the first Hot Jupiter to be discovered orbiting a pre-main sequence star. Our limit is the first to be reported for the low-frequency radio emission from this source.

  19. Ulysses radio and plasma wave observations at high southern heliographic latitudes.

    Science.gov (United States)

    Stone, R G; Macdowall, R J; Fainberg, J; Kaiser, M L; Desch, M D; Goldstein, M L; Hoang, S; Bougeret, J L; Harvey, C C; Manning, R; Steinberg, J L; Kellogg, P J; Lin, N; Goetz, K; Osherovich, V A; Reiner, M J; Canu, P; Cornilleau-Wehrlin, N; Lengyel-Frey, D; Thejappa, G

    1995-05-19

    Ulysses spacecraft radio and plasma wave observations indicate that some variations in the intensity and occurrence rate of electric and magnetic wave events are functions of heliographic latitude, distance from the sun, and phase of the solar cycle. At high heliographic latitudes, solartype Ill radio emissions did not descend to the local plasma frequency, in contrast to the emission frequencies of some bursts observed in the ecliptic. Short-duration bursts of electrostatic and electromagnetic waves were often found in association with depressions in magnetic field amplitude, known as magnetic holes. Extensive wave activity observed in magnetic clouds may exist because of unusually large electron-ion temperature ratios. The lower number of intense in situ wave events at high latitudes was likely due to the decreased variability of the high- latitude solar wind.

  20. Radio emissions from pulsar companions: a refutable explanation for galactic transients and fast radio bursts

    Science.gov (United States)

    Mottez, F.; Zarka, P.

    2014-09-01

    Context. The six known highly dispersed fast radio bursts are attributed to extragalactic radio sources that are of unknown origin but extremely energetic. We propose here a new explanation that does not require an extreme release of energy and involves a body (planet, asteroid, white dwarf) orbiting an extragalactic pulsar. Aims: We investigate a theory of radio waves associated with such pulsar-orbiting bodies. We focus our analysis on the waves emitted from the magnetic wake of the body in the pulsar wind. After deriving their properties, we compare them with the observations of various transient radio signals to determine whether they could originate from pulsar-orbiting bodies. Methods: The analysis is based on the theory of Alfvén wings: for a body immersed in a pulsar wind, a system of two stationary Alfvén waves is attached to the body, provided that the wind is highly magnetised. When they are destabilised through plasma instabilities, Alfvén wings can be the locus of strong radio sources that are convected with the pulsar wind. By assuming a cyclotron maser instability operating in the Alfvén wings, we make predictions about the shape, frequencies, and brightness of the resulting radio emissions. Results: Because of the beaming by relativistic aberration, the signal is seen only when the companion is perfectly aligned between its parent pulsar and the observer, as is the case for occultations. For pulsar winds with a high Lorentz factor (≥104), the whole duration of the radio event does not exceed a few seconds, and it is composed of one to four peaks that last a few milliseconds each and are detectable up to distances of several Mpc. The Lorimer burst, the three isolated pulses of PSR J1928+15, and the recently detected fast radio bursts are all compatible with our model. According to it, these transient signals should repeat periodically with the companion's orbital period. Conclusions: The search of pulsar-orbiting bodies could be an exploration

  1. RADIO PROPERTIES OF THE BAT AGNs: THE FIR–RADIO RELATION, THE FUNDAMENTAL PLANE, AND THE MAIN SEQUENCE OF STAR FORMATION

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Krista Lynne; Mushotzky, Richard F.; Vogel, Stuart; Shimizu, Thomas T. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Miller, Neal, E-mail: klsmith@astro.umd.edu [Department of Mathematics and Physics, Stevenson University, Stevenson, MD 21117 (United States)

    2016-12-01

    We conducted 22 GHz 1″ JVLA imaging of 70 radio-quiet active galactic nuclei (AGNs) from the Swift -BAT survey. We find radio cores in all but three objects. The radio morphologies of the sample fall into three groups: compact and core-dominated, extended, and jet-like. We spatially decompose each image into core flux and extended flux, and compare the extended radio emission with that predicted from previous Herschel observations using the canonical FIR–radio relation. After removing the AGN contribution to the FIR and radio flux densities, we find that the relation holds remarkably well despite the potentially different star formation physics in the circumnuclear environment. We also compare our core radio flux densities with predictions of coronal models and scale-invariant jet models for the origin of radio emission in radio-quiet AGNs, and find general consistency with both models. However, we find that the L {sub R}/ L {sub X} relation does not distinguish between star formation and non-relativistic AGN-driven outflows as the origin of radio emission in radio-quiet AGNs. Finally, we examine where objects with different radio morphologies fall in relation to the main sequence (MS) of star formation, and conclude that those AGNs that fall below the MS, as X-ray selected AGNs have been found to do, have core-dominated or jet-like 22 GHz morphologies.

  2. Division B Commission 40: Radio Astronomy

    NARCIS (Netherlands)

    Chapman, Jessica M.; Giovaninni, Gabriele; Taylor, Russell; Carilli, Christopher; Hills, Richard; Hirabayashi, Hisashi; Jonas, Justin L.; Lazio, Joseph; Morganti, Raffaella; Nan, Rendong; Rubio, Monica; Shastri, Prjaval; Kellermann, Ken; Ekers, Ronald; Ohishi, Masatoshi

    2016-01-01

    IAU Commission 40 for Radio Astronomy (hereafter C40) brought together scientists and engineers who carry out observational and theoretical research in radio astronomy and who develop and operate the ground and space-based radio astronomy facilities and instrumentation. As of June 2015, the

  3. Are the infrared-faint radio sources pulsars?

    Science.gov (United States)

    Cameron, A. D.; Keith, M.; Hobbs, G.; Norris, R. P.; Mao, M. Y.; Middelberg, E.

    2011-07-01

    Infrared-faint radio sources (IFRS) are objects which are strong at radio wavelengths but undetected in sensitive Spitzer observations at infrared wavelengths. Their nature is uncertain and most have not yet been associated with any known astrophysical object. One possibility is that they are radio pulsars. To test this hypothesis we undertook observations of 16 of these sources with the Parkes Radio Telescope. Our results limit the radio emission to a pulsed flux density of less than 0.21 mJy (assuming a 50 per cent duty cycle). This is well below the flux density of the IFRS. We therefore conclude that these IFRS are not radio pulsars.

  4. Zero-Power Radio Device.

    Energy Technology Data Exchange (ETDEWEB)

    Brocato, Robert W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2018-02-01

    This report describes an unpowered radio receiver capable of detecting and responding to weak signals transmit ted from comparatively long distances . This radio receiver offers key advantages over a short range zero - power radio receiver previously described in SAND2004 - 4610, A Zero - Power Radio Receiver . The device described here can be fabricated as an integrated circuit for use in portable wireless devices, as a wake - up circuit, or a s a stand - alone receiver operating in conjunction with identification decoders or other electroni cs. It builds on key sub - components developed at Sandia National Laboratories over many years. It uses surface acoustic wave (SAW) filter technology. It uses custom component design to enable the efficient use of small aperture antennas. This device uses a key component, the pyroelectric demodulator , covered by Sandia owned U.S. Patent 7397301, Pyroelectric Demodulating Detector [1] . This device is also described in Sandia owned U.S. Patent 97266446, Zero Power Receiver [2].

  5. RADIO WITHOUT A LISTENER: "MAYAK"

    Directory of Open Access Journals (Sweden)

    Bysko Maxim V.

    2017-12-01

    Full Text Available The singularity of this article is that it is entirely based on a critical analysis of only one live musical radio program on the Mayak radio station and dedicated to the life and work of the famous British composer Andrew Lloyd Webber. In principle, the article can be considered a scientific review of the media product. Based on his analysis, the author comes to the paradoxical conclusion that the presence of a listener becomes unnecessary for modern broadcasting. This is stated by many principles of the conduct of the air, presented in the radio program, where all the information load is placed on the guest in the studio, where there is no preparatory work of the DJs, where their inability to navigate the genres of journalism violates communication norms and colloquial ethics, where an obvious deconstructive approach to the material offered for the listener. In addition, the phenomenon of being the DJs in the radio studio exclusively "for themselves" is emphasized by the sound design of the radio program, which runs counter to the logic of auditory perception (for example, the sequence of jingles, as well as the incompetent selection of musical material, which undoubtedly repels professional radio listeners-musicians.

  6. DISCOVERY OF ULTRA-STEEP SPECTRUM GIANT RADIO GALAXY WITH RECURRENT RADIO JET ACTIVITY IN ABELL 449

    International Nuclear Information System (INIS)

    Hunik, Dominika; Jamrozy, Marek

    2016-01-01

    We report a discovery of a 1.3 Mpc diffuse radio source with extremely steep spectrum fading radio structures in the vicinity of the Abell 449 cluster of galaxies. Its extended diffuse lobes are bright only at low radio frequencies and their synchrotron age is about 160 Myr. The parent galaxy of the extended relic structure, which is the dominant galaxy within the cluster, is starting a new jet activity. There are three weak X-rays sources in the vicinity of the cluster as found in the ROSAT survey, however it is not known if they are connected with this cluster of galaxies. Just a few radio galaxy relics are currently known in the literature, as finding them requires sensitive and high angular resolution low-frequency radio observations. Objects of this kind, which also are starting a new jet activity, are important for understanding the life cycle and evolution of active galactic nuclei. A new 613 MHz map as well as the archival radio data pertaining to this object are presented and analyzed

  7. How safe is tuning a radio?: using the radio tuning task as a benchmark for distracted driving.

    Science.gov (United States)

    Lee, Ja Young; Lee, John D; Bärgman, Jonas; Lee, Joonbum; Reimer, Bryan

    2018-01-01

    Drivers engage in non-driving tasks while driving, such as interactions entertainment systems. Studies have identified glance patterns related to such interactions, and manual radio tuning has been used as a reference task to set an upper bound on the acceptable demand of interactions. Consequently, some view the risk associated with radio tuning as defining the upper limit of glance measures associated with visual-manual in-vehicle activities. However, we have little knowledge about the actual degree of crash risk that radio tuning poses and, by extension, the risk of tasks that have similar glance patterns as the radio tuning task. In the current study, we use counterfactual simulation to take the glance patterns for manual radio tuning tasks from an on-road experiment and apply these patterns to lead-vehicle events observed in naturalistic driving studies. We then quantify how often the glance patterns from radio tuning are associated with rear-end crashes, compared to driving only situations. We used the pre-crash kinematics from 34 crash events from the SHRP2 naturalistic driving study to investigate the effect of radio tuning in crash-imminent situations, and we also investigated the effect of radio tuning on 2,475 routine braking events from the Safety Pilot project. The counterfactual simulation showed that off-road glances transform some near-crashes that could have been avoided into crashes, and glance patterns observed in on-road radio tuning experiment produced 2.85-5.00 times more crashes than baseline driving. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Radio halo sources in clusters of galaxies

    International Nuclear Information System (INIS)

    Hanisch, R.J.

    1986-01-01

    Radio halo sources remain one of the most enigmatic of all phenomena related to radio emission from galaxies in clusters. The morphology, extent, and spectral structure of these sources are not well known, and the models proposed to explain them suffer from this lack of observational detail. However, recent observations suggest that radio halo sources may be a composite of relic radio galaxies. The validity of this model could be tested using current and planned high resolutions, low-frequency radio telescopes. 31 references

  9. Mengusung Masyarakat Madani Melalui Radio Komunitas

    Directory of Open Access Journals (Sweden)

    Dede Lilis Chaerowati

    2013-12-01

    Full Text Available This article is about the phenomenon of community radio in Pantura Area, West Java. Radio communities maganed by, for and about the community are rapidly developing among the farmers and fishermen, including in Pantura Area, West Java. The focus of the study is the formation of civil society by standing firmly on communicative actions of Jürgen Habermas. By using qualitative method with case study design, a finding would be produced that community radios implement participatory paradigm and manage community cohesion. We will discuss in details on: (1 initiators of the establishment of community radio, (2 forms of community participation, (3 the financing source of community radio, and (4 the construction of civil society through community radio. This article also covers about how the people see the world of life, that there is social transformation through emancipatordialogs, which then produce community’s selfconsciousness  as individuals and community members in demanding a domination-free communication process. This reality creates the origination of civil society.

  10. 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.

  11. Considerations for the Next Revision of NASA's Space Telecommunications Radio System Architecture

    Science.gov (United States)

    Johnson, Sandra K.; Handler, Louis M.; Briones, Janette C.

    2016-01-01

    Development of NASA's Software Defined Radio architecture, the Space Telecommunication Radio System (STRS), was initiated in 2004 with a goal of reducing the cost, risk and schedule when implementing Software Defined Radios (SDR) for National Aeronautics and Space Administration (NASA) space missions. Since STRS was first flown in 2012 on three Software Defined Radios on the Space Communication and Navigation (SCaN) Testbed, only minor changes have been made to the architecture. Multiple entities have since implemented the architecture and provided significant feedback for consideration for the next revision of the standard. The focus for the first set of updates to the architecture is items that enhance application portability. Items that require modifications to existing applications before migrating to the updated architecture will only be considered if there is compelling reasons to make the change. The significant suggestions that were further evaluated for consideration include expanding and clarifying the timing Application Programming Interfaces (APIs), improving handle name and identification (ID) definitions and use, and multiple items related to implementation of STRS Devices. In addition to ideas suggested while implementing STRS, SDR technology has evolved significantly and this impact to the architecture needs to be considered. These include incorporating cognitive concepts - learning from past decisions and making new decisions that the radio can act upon. SDRs are also being developed that do not contain a General Purpose Module - which is currently required for the platform to be STRS compliant. The purpose of this paper is to discuss the comments received, provide a summary of the evaluation considerations, and examine planned dispositions.

  12. The Gamma-Ray Emitting Radio-Loud Narrow-Line Seyfert 1 Galaxy PKS 2004-447 II. The Radio View

    Science.gov (United States)

    Schulz, R.; Kreikenbohm, A.; Kadler, M.; Ojha, R.; Ros, E.; Stevens, J.; Edwards, P. G.; Carpenter, B.; Elsaesser, D.; Gehrels, N.; hide

    2016-01-01

    Context. gamma-ray-detected radio-loud narrow-line Seyfert 1 (gamma-NLS1) galaxies constitute a small but interesting sample of the gamma-ray-loud AGN. The radio-loudest gamma-NLS1 known, PKS2004447, is located in the southern hemisphere and is monitored in the radio regime by the multiwavelength monitoring programme TANAMI. Aims. We aim for the first detailed study of the radio morphology and long-term radio spectral evolution of PKS2004447, which are essential for understanding the diversity of the radio properties of gamma-NLS1s. Methods. The TANAMI VLBI monitoring program uses the Australian Long Baseline Array (LBA) and telescopes in Antarctica, Chile, New Zealand, and South Africa to monitor the jets of radio-loud active galaxies in the southern hemisphere. Lower resolution radio flux density measurements at multiple radio frequencies over four years of observations were obtained with the Australia Telescope Compact Array (ATCA). Results. The TANAMI VLBI image at 8.4GHz shows an extended one-sided jet with a dominant compact VLBI core. Its brightness temperature is consistent with equipartition, but it is an order of magnitude below other gamma-NLS1s with the sample value varying over two orders of magnitude. We find a compact morphology with a projected large-scale size 11 kpc and a persistent steep radio spectrum with moderate flux-density variability. Conclusions. PKS2004447 appears to be a unique member of the gamma-NLS1 sample. It exhibits blazar-like features, such as a flat featureless X-ray spectrum and a core-dominated, one-sided parsec-scale jet with indications for relativistic beaming. However, the data also reveal properties atypical for blazars, such as a radio spectrum and large-scale size consistent with compact-steep-spectrum (CSS) objects, which are usually associated with young radio sources. These characteristics are unique among all gamma-NLS1s and extremely rare among gamma-ray-loud AGN.

  13. EFFICIENT SPECTRUM UTILIZATION IN COGNITIVE RADIO THROUGH REINFORCEMENT LEARNING

    Directory of Open Access Journals (Sweden)

    Dhananjay Kumar

    2013-09-01

    Full Text Available Machine learning schemes can be employed in cognitive radio systems to intelligently locate the spectrum holes with some knowledge about the operating environment. In this paper, we formulate a variation of Actor Critic Learning algorithm known as Continuous Actor Critic Learning Automaton (CACLA and compare this scheme with Actor Critic Learning scheme and existing Q–learning scheme. Simulation results show that our CACLA scheme has lesser execution time and achieves higher throughput compared to other two schemes.

  14. Validation of an immunochemical assay for the detection of DNA damage as a tool for biological dosimetry of human exposure to ionizing radiation

    International Nuclear Information System (INIS)

    Schans, G.P. van der; Timmerman, A.J.; Wojewodzka, M.; Zaim, J.

    1997-01-01

    A method for biological dosimetry based on the immunochemical detection of DNA damage in human white blood cells has been validated. To this end the method developed at TNO (Rijswijk, the Netherlands) was also set up at INCT (Warsaw, Poland). Blood samples of 11 individuals were irradiated with 0 or 5 Gy of 170 kV X-rays at INCT and analyzed both at INCT and TNO. It appeared that in both laboratories damage could be detected to the same extent. The average background level of DNA damage amounted to 1.0 Gy-eq with an interindividual standard deviation of 0.25 Gy. The contribution of the sample variance to the total variance is only 14%. The radiosensitivity showed only a variation of about 10% and can, therefore, be neglected in estimating the radiation dose from the amount of DNA damage detected. (author)

  15. Case Study: Using The OMG SWRADIO Profile and SDR Forum Input for NASA's Space Telecommunications Radio System

    Science.gov (United States)

    Briones, Janette C.; Handler, Louis M.; Hall, Steve C.; Reinhart, Richard C.; Kacpura, Thomas J.

    2009-01-01

    The Space Telecommunication Radio System (STRS) standard is a Software Defined Radio (SDR) architecture standard developed by NASA. The goal of STRS is to reduce NASA s dependence on custom, proprietary architectures with unique and varying interfaces and hardware and support reuse of waveforms across platforms. The STRS project worked with members of the Object Management Group (OMG), Software Defined Radio Forum, and industry partners to leverage existing standards and knowledge. This collaboration included investigating the use of the OMG s Platform-Independent Model (PIM) SWRadio as the basis for an STRS PIM. This paper details the influence of the OMG technologies on the STRS update effort, findings in the STRS/SWRadio mapping, and provides a summary of the SDR Forum recommendations.

  16. 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.

  17. Propagation of Energetic Electrons from the Corona into Interplanetary Space and Type III Radio Emission. Planetary Radio Emissions| PLANETARY RADIO EMISSIONS VII 7|

    OpenAIRE

    Vocks, C.; Breitling, F.; Mann, G.

    2011-01-01

    During solar flares a large amount of electrons with energies greater than 20 keV is generated with a production rate of typically 1036 s-1. A part of them is able to propagate along open magnetic field lines through the corona into interplanetary space. During their travel they emit radio radiation which is observed as type III radio bursts in the frequency range from 100 MHz down to 10 kHz by the WAVES radio spectrometer aboard the spacecraft WIND, for instance. From the drift rates of thes...

  18. The Velocity Distribution of Isolated Radio Pulsars

    Science.gov (United States)

    Arzoumanian, Z.; Chernoff, D. F.; Cordes, J. M.; White, Nicholas E. (Technical Monitor)

    2002-01-01

    We infer the velocity distribution of radio pulsars based on large-scale 0.4 GHz pulsar surveys. We do so by modelling evolution of the locations, velocities, spins, and radio luminosities of pulsars; calculating pulsed flux according to a beaming model and random orientation angles of spin and beam; applying selection effects of pulsar surveys; and comparing model distributions of measurable pulsar properties with survey data using a likelihood function. The surveys analyzed have well-defined characteristics and cover approx. 95% of the sky. We maximize the likelihood in a 6-dimensional space of observables P, dot-P, DM, absolute value of b, mu, F (period, period derivative, dispersion measure, Galactic latitude, proper motion, and flux density). The models we test are described by 12 parameters 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 E(exp 1/2) 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; this preference is largely immune to variations in other population parameters, such as the luminosity or distance scale, or the assumed spin-down law. We explore some consequences of the preferred birth velocity distribution: (1) roughly 50% of pulsars in the solar neighborhood will escape the Galaxy, while approx. 15% have velocities greater than 1000 km/ s (2) observational bias against high velocity pulsars is relatively unimportant for surveys that reach high Galactic absolute value of z distances, but is severe for

  19. Hybrid Experiential-Heuristic Cognitive Radio Engine Architecture and Implementation

    Directory of Open Access Journals (Sweden)

    Ashwin Amanna

    2012-01-01

    Full Text Available The concept of cognitive radio (CR focuses on devices that can sense their environment, adapt configuration parameters, and learn from past behaviors. Architectures tend towards simplified decision-making algorithms inspired by human cognition. Initial works defined cognitive engines (CEs founded on heuristics, such as genetic algorithms (GAs, and case-based reasoning (CBR experiential learning algorithms. This hybrid architecture enables both long-term learning, faster decisions based on past experience, and capability to still adapt to new environments. This paper details an autonomous implementation of a hybrid CBR-GA CE architecture on a universal serial radio peripheral (USRP software-defined radio focused on link adaptation. Details include overall process flow, case base structure/retrieval method, estimation approach within the GA, and hardware-software lessons learned. Unique solutions to realizing the concept include mechanisms for combining vector distance and past fitness into an aggregate quantification of similarity. Over-the-air performance under several interference conditions is measured using signal-to-noise ratio, packet error rate, spectral efficiency, and throughput as observable metrics. Results indicate that the CE is successfully able to autonomously change transmit power, modulation/coding, and packet size to maintain the link while a non-cognitive approach loses connectivity. Solutions to existing shortcomings are proposed for improving case-base searching and performance estimation methods.

  20. RADIO-WEAK BL LAC OBJECTS IN THE FERMI ERA

    Energy Technology Data Exchange (ETDEWEB)

    Massaro, F.; Marchesini, E. J. [Dipartimento di Fisica, Università degli Studi di Torino (UniTO), via Pietro Giuria 1, I-10125 Torino (Italy); D’Abrusco, R.; Smith, Howard A. [Smithsonian Astrophysical Observatory, 60 Garden Street, 02138 Cambridge, MA (United States); Masetti, N. [INAF—Istituto di Astrofisica Spaziale e Fisica Cosmica di Bologna, via Gobetti 101, I-40129, Bologna (Italy); Andruchow, I. [Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata, Paseo del Bosque, B1900FWA, La Plata (Argentina)

    2017-01-10

    The existence of “radio-weak BL Lac objects” (RWBLs) has been an open question, and has remained unsolved since the discovery that quasars could be radio-quiet or radio-loud. Recently, several groups identified RWBL candidates, mostly found while searching for low-energy counterparts of the unidentified or unassociated gamma-ray sources listed in the Fermi catalogs. Confirming RWBLs is a challenging task since they could be confused with white dwarfs (WDs) or weak emission line quasars (WELQs) when there are not sufficient data to precisely draw their broadband spectral energy distribution, and their classification is mainly based on a featureless optical spectra. Motivated by the recent discovery that Fermi BL Lacs appear to have very peculiar mid-IR emission, we show that it is possible to distinguish between WDs, WELQs, and BL Lacs using the [3.4]–[4.6]–[12] μ m color–color plot built using the WISE magnitudes when the optical spectrum is available. On the basis of this analysis, we identify WISE J064459.38+603131 and WISE J141046.00+740511.2 as the first two genuine RWBLs, both potentially associated with Fermi sources. Finally, to strengthen our identification of these objects as true RWBLs, we present multifrequency observations for these two candidates to show that their spectral behavior is indeed consistent with that of the BL Lac population.

  1. RADIO-WEAK BL LAC OBJECTS IN THE FERMI ERA

    International Nuclear Information System (INIS)

    Massaro, F.; Marchesini, E. J.; D’Abrusco, R.; Smith, Howard A.; Masetti, N.; Andruchow, I.

    2017-01-01

    The existence of “radio-weak BL Lac objects” (RWBLs) has been an open question, and has remained unsolved since the discovery that quasars could be radio-quiet or radio-loud. Recently, several groups identified RWBL candidates, mostly found while searching for low-energy counterparts of the unidentified or unassociated gamma-ray sources listed in the Fermi catalogs. Confirming RWBLs is a challenging task since they could be confused with white dwarfs (WDs) or weak emission line quasars (WELQs) when there are not sufficient data to precisely draw their broadband spectral energy distribution, and their classification is mainly based on a featureless optical spectra. Motivated by the recent discovery that Fermi BL Lacs appear to have very peculiar mid-IR emission, we show that it is possible to distinguish between WDs, WELQs, and BL Lacs using the [3.4]–[4.6]–[12] μ m color–color plot built using the WISE magnitudes when the optical spectrum is available. On the basis of this analysis, we identify WISE J064459.38+603131 and WISE J141046.00+740511.2 as the first two genuine RWBLs, both potentially associated with Fermi sources. Finally, to strengthen our identification of these objects as true RWBLs, we present multifrequency observations for these two candidates to show that their spectral behavior is indeed consistent with that of the BL Lac population.

  2. Ionospheric Caustics in Solar Radio Observations

    Science.gov (United States)

    Koval, A.; Chen, Y.; Stanislavsky, A.

    2016-12-01

    The Earth ionosphere possesses by natural focusing and defocusing effects on radio waves due to presence of variable ionospheric irregularities which could act like convergent and divergent lenses on incident radiation. In particular, the focusing of emission from the Sun was firstly detected on the Nançay Decameter Array dynamic spectra in the 1980s. On time-frequency spectrograms the intensity variations form specific structures different from well-known solar radio bursts and clearly distinguishing on a background of solar radiation. Such structures have been identified as ionospheric caustics (ICs) and considered to be the result of radio waves refraction on medium scale travelling ionospheric disturbances (MSTIDs). Although nowadays the ICs are registered by different radio observatories due to augmentation of low-frequency radio telescopes, the most recent papers devoted to ICs in solar radio records date back to the 1980s. In this study, we revisit the ICs issue with some new results by conducting a statistical analysis of occurrence rate of ICs in solar dynamic spectra in meter-decameter wavelength range for long continuous period (15 years). The seasonal variations in ICs appearance have been found for the first time. Besides, we report the possible solar cycle dependence of ICs emergence. The radio waves propagation in the ionosphere comprising MSTIDs will be considered. The present research renews the subject of ICs in the low-frequency solar radio astronomy after about 35-year letup.

  3. The properties of radio ellipticals

    International Nuclear Information System (INIS)

    Sparks, W.B.; Disney, M.J.; Rodgers, A.W.

    1984-01-01

    Optical and additional radio data are presented for the bright galaxies of the Disney and Wall survey (1977 Mon. Not. R. Astron. Soc. 179, 235). These data form the basis of a statistical comparison of the properties of radio elliptical galaxies to radio-quiet ellipticals. The correlations may be explained by the depth of the gravitational potential well in which the galaxy resides governing the circumstances under which an elliptical galaxy rids itself of internally produced gas. (author)

  4. Radio and the Church – a Historical Glance

    Directory of Open Access Journals (Sweden)

    Carl-Mario Sultana

    2014-09-01

    Full Text Available Radio is a very powerful mass communication medium. In radio broadcasting, one can hear the echo of Christ’s words to his apostles in the missionary discourse: “You received without charge, give without charge...What you hear in whispers, proclaim from the house tops” (Mt 10,8b.27. Although the Church uses radio as a means to transmit the Good News of salvation, and we as human beings receive radio transmissions as a part of our daily life, we barely stop to think and reflect upon the underlying aspects of radio as a means of communication. In this paper, the Author endeavours to give a historical overview of what makes radio an important medium for evangelisation according to four key documents of the Church, while also studying the underlying theological positions found in these documents. These documents enable us to study radio as a broadcasting medium, highlighting the possible reactions of the Church to radio and how the Church changed its stance on radio over the years. The reason for focussing specifically on radio is for two particular reasons: from the very beginning, the Church has considered radio as a means for evangelising the masses. Notwithstanding this, what is going to be discussing in the paper can be equally applied to Television as a mass communication medium. Secondly, the Church took an active role in radio broadcasting by asking Guglielmo Marconi himself to construct the Vatican Radio in 1931. The documents of the Church also offer us a theology of radio as a mass communication medium, with unity, progress and evangelisation being the fundamental aspects. Church documents posit that not everything should be broadcasted over radio but only messages which bring about peace and unity.

  5. 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

  6. DIFFERENCES BETWEEN RADIO-LOUD AND RADIO-QUIET γ -RAY PULSARS AS REVEALED BY FERMI

    Energy Technology Data Exchange (ETDEWEB)

    Hui, C. Y.; Lee, Jongsu [Department of Astronomy and Space Science, Chungnam National University, Daejeon (Korea, Republic of); Takata, J. [Institute of Particle physics and Astronomy, Huazhong University of Science and Technology (China); Ng, C. W.; Cheng, K. S., E-mail: cyhui@cnu.ac.kr, E-mail: takata@hust.edu.cn [Department of Physics, University of Hong Kong, Pokfulam Road (Hong Kong)

    2017-01-10

    By comparing the properties of non-recycled radio-loud γ -ray pulsars and radio-quiet γ -ray pulsars, we have searched for the differences between these two populations. We found that the γ -ray spectral curvature of radio-quiet pulsars can be larger than that of radio-loud pulsars. Based on the full sample of non-recycled γ -ray pulsars, their distributions of the magnetic field strength at the light cylinder are also found to be different. We note that this might result from an observational bias. By reexamining the previously reported difference of γ -ray-to-X-ray flux ratios, we found that the significance can be hampered by their statistical uncertainties. In the context of the outer gap model, we discuss the expected properties of these two populations and compare with the possible differences that are identified in our analysis.

  7. 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

  8. The Spectrum Landscape: Prospects for Terrestrial Radio Astronomy

    Science.gov (United States)

    Liszt, Harvey Steven

    2018-01-01

    Radio astronomers work within broad constraints imposed by commercial and other non-astronomical uses of the radio spectrum, somewhat modified to accommodate astronomy’s particular needs through the provision of radio quiet zones, radio frequency allocations, coordination agreements and other devices of spectrum management. As radio astronomers increase the instantaneous bandwidth, frequency coverage and sensitivity of their instruments, these external constraints, and not the limitations of their own instruments, will increasingly be the greatest obstacles to radio astronomy’s ability to observe the cosmos from the surface of the Earth. Therefore, prospects for future radio astronomy operations are contingent on situational awareness and planning for the impact of non-astronomical uses of the radio frequency spectrum. New radio astronomy instruments will have to incorporate adaptive reactions to external developments, and radio astronomers should be encouraged to think in untraditional ways. Increased attention to spectrum management is one of these. In this talk I’ll recap some recent developments such as the proliferation of 76 – 81 GHz car radar and orbiting earth-mapping radars, either of which can burn out a radio astronomy receiver. I’ll summarize present trends for non-astronomical radio spectrum use that will be coming to fruition in the next decade or so, categorized into terrestrial fixed and mobile, airborne and space-borne uses, sub-divided by waveband from the cm to the sub-mm. I’ll discuss how they will impact terrestrial radio astronomy and the various ways in which radio astronomy should be prepared to react. Protective developments must occur both within radio astronomy’s own domain – designing, siting and constructing its instruments and mitigating unavoidable RFI – and facing outward toward the community of other spectrum users. Engagement with spectrum management is no panacea but it is an important means, and perhaps the only

  9. 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...

  10. La radio: aquellos primeros años

    Directory of Open Access Journals (Sweden)

    Luis Dávila Loor

    2015-01-01

    Full Text Available El autor reseña lo que fueron los primeros años de la radio, pues luego de inventado el telégrafo, el gramófono y el teléfono, estaban dados los ingredientes para inventar la radio. Las dos primeras décadas la radio fue utilizada para fines militares y marítimos. En los años 20 llegó a su máximo apogeo. Advino más tarde(1924 el radio teatro. La disonancia no lo desanimaba, Edison seguramente estaba convencido que un siglo después aparecerían los compac disks, en los que se escucharían con absoluta fidelidad las bulliciosas pero armoniosas canciones de un cantante negro con facha de mujer blanca. Con el desarrollo de la televisión vino el declive de la radio tradicional pero se inicio la etapa de la radio compañera que más tarde dio a lugar a la radio comunitaria.

  11. Analysis of control and management plane for hybrid fiber radio architectures

    DEFF Research Database (Denmark)

    Kardaras, Georgios; Pham, Tien Thang; Soler, José

    2010-01-01

    This paper presents the existing Radio over Fiber (RoF) architectures and focuses on the control and management plane of the Remote Antenna Unit (RAU). Broadband wireless standards, such as WiMAX and LTE, incorporate optical technologies following the distributed base station concept. The control...... and management of the RAU becomes a critical task, since it can facilitate allocation of resources, configuration and upgrade of the remote unit and constant monitoring of its performance. In the case of baseband over fiber, two protocols (OBSAI and CPRI) introduce a well-defined control and management plane....... In the case of intermediate/radio frequency over fiber, this paper presents a simple approach, which can provide configurability and real-time monitoring of the RAU over the same optical link. This is realized by multiplexing high frequency user data with baseband frequency control data at the Central Office...

  12. Radio recombination lines from H II regions

    International Nuclear Information System (INIS)

    Silverglate, P.R.

    1978-01-01

    Radio recombination lines have been observed from forty-six H II regions. The Arecibo 1000-foot radio telescope was used to provide high sensitivity and high angular resolution at 1400 MHz (gain approx. 7.7 0 K/Jy, HPBW = 3:2) and 2372 MHZ (gain approx. 6.3 0 K/Jy, HPBW = 2'). Observations were made at 1400 MHz in the frequency switching mode, and at 2372 MHz in the total power mode. Gaussians were fit to be observed lines to derive velocities, line widths, and line temperatures. From the velocities kinematic distances were derived. For eleven sources H I absorption measurements were also made. The absorption spectra enabled the kinematic distance ambiguity to be resolved for some sources. The absorption spectra themselves were found to have extremely sharp, non-gaussian edges. One explanation for these is a model where the interstellar medium contains many H I cloudlets with T/sub s/less than or equal to 100 0 K and turbulent velocities less than or equal to 3 km/s. The H I absorption spectrum is then a superposition of many narrow gaussian profiles. It was also found from a comparison of H I absorption velocities with radio recombination line velocities that peculiar motions exist in the interstellar medium with velocities of up to 10 km/s. Using the measured line temperatures and continuum temperatures, estimates were desired of emission measures, electron temperatures, and electron densities, using a non-LTE analysis. Non-LTE effects were important only for the hottest and densest H II regions. The non-LTE calculations were checked through a comparison derivation of electron temperatures using hydrogen beta lines

  13. A Dynamic Spectrum Allocation Algorithm for a Maritime Cognitive Radio Communication System Based on a Queuing Model

    Directory of Open Access Journals (Sweden)

    Jingbo Zhang

    2017-09-01

    Full Text Available With the rapid development of maritime digital communication, the demand for spectrum resources is increasing, and building a maritime cognitive radio communication system is an effective solution. In this paper, the problem of how to effectively allocate the spectrum for secondary users (SUs with different priorities in a maritime cognitive radio communication system is studied. According to the characteristics of a maritime cognitive radio and existing research about cognitive radio systems, this paper establishes a centralized maritime cognitive radio communication model and creates a simplified queuing model with two queues for the communication model. In the view of the behaviors of SUs and primary users (PUs, we propose a dynamic spectrum allocation (DSA algorithm based on the system status, and analyze it with a two-dimensional Markov chain. Simulation results show that, when different types of SUs have similar arrival rates, the algorithm can vary the priority factor according to the change of users’ status in the system, so as to adjust the channel allocation, decreasing system congestion. The improvement of the algorithm is about 7–26%, and the specific improvement is negatively correlated with the SU arrival rate.

  14. SUPERCONDUCTING RADIO-FREQUENCY MODULES TEST FACILITY OPERATING EXPERIENCE

    International Nuclear Information System (INIS)

    Soyars, W.; Bossert, R.; Darve, C.; Degraff, B.; Klebaner, A.; Martinez, A.; Pei, L.; Theilacker, J.

    2008-01-01

    Fermilab is heavily engaged and making strong technical contributions to the superconducting radio-frequency research and development program (SRF R and D). Four major SRF test areas are being constructed to enable vertical and horizontal cavity testing, as well as cryomodule testing. The existing Fermilab cryogenic infrastructure has been modified to service the SRF R and D needs. The project's first stage has been successfully completed, which allows for distribution of cryogens for a single-cavity cryomodule using the existing Cryogenic Test Facility (CTF) that houses three Tevatron satellite refrigerators. The cooling capacity available for cryomodule testing at Meson Detector Building (MDB) results from the liquefaction capacity of the CTF cryogenic system. The cryogenic system for a single 9-cell cryomodule is currently operational. The paper describes the status, challenges and operational experience of the initial phase of the project

  15. Recent results of zebra patterns in solar radio bursts

    International Nuclear Information System (INIS)

    Chernov, Gennady P.

    2010-01-01

    This review covers the most recent experimental results and theoretical research on zebra patterns (ZPs) in solar radio bursts. The basic attention is given to events with new peculiar elements of zebra patterns received over the last few years. All new properties are considered in light of both what was known earlier and new theoretical models. Large-scale ZPs consisting of small-scale fiber bursts could be explained by simultaneous inclusion of two mechanisms when whistler waves 'highlight' the levels of double plasma resonance (DPR). A unique fine structure was observed in the event on 2006 December 13: spikes in absorption formed dark ZP stripes against the absorptive type III-like bursts. The spikes in absorption can appear in accordance with well known mechanisms of absorptive bursts. The additional injection of fast particles filled the loss-cone (breaking the loss-cone distribution), and the generation of the continuum was quenched at these moments. The maximum absorptive effect occurs at the DPR levels. The parameters of millisecond spikes are determined by small dimensions of the particle beams and local scale heights in the radio source. Thus, the DPR model helps to understand several aspects of unusual elements of ZPs. However, the simultaneous existence of several tens of the DPR levels in the corona is impossible for any realistic profile of the plasma density and magnetic field. Three new theories of ZPs are examined. The formation of eigenmodes of transparency and opacity during the propagation of radio waves through regular coronal inhomogeneities is the most natural and promising mechanism. Two other models (nonlinear periodic space - charge waves and scattering of fast protons on ion-sound harmonics) could happen in large radio bursts. (invited reviews)

  16. Radio Flares from Gamma-ray Bursts

    Science.gov (United States)

    Kopač, D.; Mundell, C. G.; Kobayashi, S.; Virgili, F. J.; Harrison, R.; Japelj, J.; Guidorzi, C.; Melandri, A.; Gomboc, A.

    2015-06-01

    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.

  17. RADIO FLARES FROM GAMMA-RAY BURSTS

    International Nuclear Information System (INIS)

    Kopač, D.; Mundell, C. G.; Kobayashi, S.; Virgili, F. J.; Harrison, R.; Japelj, J.; Gomboc, A.; Guidorzi, C.; Melandri, A.

    2015-01-01

    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

  18. Multicenter pilot study of radio-chemotherapy as first-line treatment for adults with medulloblastoma (NOA-07)

    DEFF Research Database (Denmark)

    Dagmar, Dagmar; Proescholdt, Martin; Reinert, Christiane

    2018-01-01

    Background: Medulloblastoma in adult patients is rare, with 0.6 cases per million. Prognosis depends on clinical factors and medulloblastoma entity. No prospective data on the feasibility of radio-chemotherapy exist. The German Neuro-Oncology Working Group (NOA) performed a prospective descriptiv...

  19. Radio Astronomy at TIFR, some highlights and reminiscences

    Science.gov (United States)

    Swarup, G.

    Radio astronomy research was initiated at TIFR fifty years ago. In this historical article, I firstly trace my initiation in the field of radio astronomy during 1953-55 in the Radio Physics Laboratory of CSIRO in Australia and later during 1956-63 in USA. In September 1961, four radio astronomers working abroad wrote to a number of scientific organizations in India with their desire to start radio astronomy research in India. Soon thereafter Dr. Homi Bhabha, the founder Director of TIFR, approved the formation of a radio astronomy group therein. I joined TIFR in April 1963. During the last 50 years, TIFR has built two of the world's largest radio telescopes, namely the 530m long and 30 m wide parabolic cylinder equatorially mounted on a hill at Ooty in South India during 1960s and the Giant Metrewave Radio Telescope near Pune, consisting of 30 nos. of fully steerable parabolic dishes of 45 m diameters during 1990s. Fifty years of radio astronomy research at TIFR is briefly highlighted here.

  20. Redes de participación e intercambios en la radio pública: los podcasting Networks of Participation and Communicative Interchanges in Public Radio: Podcasting

    Directory of Open Access Journals (Sweden)

    Carmen Salgado Santamaría

    2009-10-01

    Full Text Available El desarrollo de los podcasting, como sistema añadido de la ciberradio, impulsa a las redes de participación e intercambios comunicativos de interés social, que exhiben numerosas ventajas frente a las prácticas radiofónicas conocidas. La difusión que la radio pública realiza de los podcasts, la colocan en el actual proceso de convergencia tecnológica, y la sitúan en una sociedad de la información y del conocimiento, capaz de ofrecer diferentes servicios al alcance de todos los ciudadanos. Sólo la introducción de nuevos contenidos y servicios que aporten valor añadido a los existentes y satisfagan las necesidades de sus usuarios, procurarán la rentabilidad de este sistema. The development of podcasting as an additional system of cyberradio stimulates the appearance of networks of participation and communicative interchanges of social interest, and has numerous advantages over conventional radio practices. The spreading of podcasts through public radio situates it within the process of technological convergence and in an Information and Knowledge society which is able to offer different services within reach of all citizens. Only the introduction of new contents and services that contribute added value to the existing ones and satisfy the needs of users will make this system profitable.

  1. Elaborate analysis and design of filter-bank-based sensing for wideband cognitive radios

    Science.gov (United States)

    Maliatsos, Konstantinos; Adamis, Athanasios; Kanatas, Athanasios G.

    2014-12-01

    The successful operation of a cognitive radio system strongly depends on its ability to sense the radio environment. With the use of spectrum sensing algorithms, the cognitive radio is required to detect co-existing licensed primary transmissions and to protect them from interference. This paper focuses on filter-bank-based sensing and provides a solid theoretical background for the design of these detectors. Optimum detectors based on the Neyman-Pearson theorem are developed for uniform discrete Fourier transform (DFT) and modified DFT filter banks with root-Nyquist filters. The proposed sensing framework does not require frequency alignment between the filter bank of the sensor and the primary signal. Each wideband primary channel is spanned and monitored by several sensor subchannels that analyse it in narrowband signals. Filter-bank-based sensing is proved to be robust and efficient under coloured noise. Moreover, the performance of the weighted energy detector as a sensing technique is evaluated. Finally, based on the Locally Most Powerful and the Generalized Likelihood Ratio test, real-world sensing algorithms that do not require a priori knowledge are proposed and tested.

  2. Community Radio in Political Theory and Development Practice

    African Journals Online (AJOL)

    zeleza

    These structural and conceptual elements provide community radio the ... characteristic problems of development projects based on its theoretical and structural .... and to fix basic radio equipment is a standard practice of community radio stations. ... community radio stations and participatory media organizations, but also ...

  3. Two-way radios and scanners for dummies

    CERN Document Server

    Silver, H Ward

    2013-01-01

    Discover a fun new hobby with helpful possibilities Get directions, talk to folks overseas, or find out whether the fish are biting Want to check out the morning news in London, help out in emergencies, or tune in to the big race? Two-way radios open up a world of possibilities - literally. This handy guide tells you about the equipment you need, fills you in on radio etiquette, shows you how to stay legal, and gives you lots of cool ideas for family-friendly radio activities. Discover how to * Use the right radio lingo * Choose and operate different types of radios * Get a license if you n

  4. Radio jets and gamma-ray emission in radio-silent narrow-line Seyfert 1 galaxies

    Science.gov (United States)

    Lähteenmäki, A.; Järvelä, E.; Ramakrishnan, V.; Tornikoski, M.; Tammi, J.; Vera, R. J. C.; Chamani, W.

    2018-06-01

    We have detected six narrow-line Seyfert 1 (NLS1) galaxies at 37 GHz that were previously classified as radio silent and two that were classified as radio quiet. These detections reveal the presumption that NLS1 galaxies labelled radio quiet or radio silent and hosted by spiral galaxies are unable to launch jets to be incorrect. The detections are a plausible indicator of the presence of a powerful, most likely relativistic jet because this intensity of emission at 37 GHz cannot be explained by, for example, radiation from supernova remnants. Additionally, one of the detected NLS1 galaxies is a newly discovered source of gamma rays and three others are candidates for future detections. 37 GHz data are only available in electronic form at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/614/L1

  5. 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.

  6. 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.

  7. Radio structure in quasars

    International Nuclear Information System (INIS)

    Barthel, P.D.

    1984-01-01

    In this thesis, observational attention is given to the extended extragalactic radio sources associated with quasars. The isolated compact radio sources, often identified with quasars, are only included in the discussions. Three aspects of the radio structure in quasars and their cosmic evolution are considered: a study of the parsec scale morphology in quasar cores, in relation to the extended morphologies; an investigation of possible epoch dependent hotspot properties as well as a more detailed investigation of this fine scale structure; a VLA project was carried out to obtain morphological information on scales of 0.5 arcsec on high redshift quasars and to investigate possible epoch dependent morphological properties. MERLIN observations at 0.1 arcsec resolution to supplement the VLA data were initiated. (Auth.)

  8. An Energy-Efficient Game-Theory-Based Spectrum Decision Scheme for Cognitive Radio Sensor Networks.

    Science.gov (United States)

    Salim, Shelly; Moh, Sangman

    2016-06-30

    A cognitive radio sensor network (CRSN) is a wireless sensor network in which sensor nodes are equipped with cognitive radio. In this paper, we propose an energy-efficient game-theory-based spectrum decision (EGSD) scheme for CRSNs to prolong the network lifetime. Note that energy efficiency is the most important design consideration in CRSNs because it determines the network lifetime. The central part of the EGSD scheme consists of two spectrum selection algorithms: random selection and game-theory-based selection. The EGSD scheme also includes a clustering algorithm, spectrum characterization with a Markov chain, and cluster member coordination. Our performance study shows that EGSD outperforms the existing popular framework in terms of network lifetime and coordination overhead.

  9. VizieR Online Data Catalog: SEDs of the radio continuum from KINGFISHER (Tabatabaei+, 2017)

    Science.gov (United States)

    Tabatabaei, F. S.; Schinnerer, E.; Krause, M.; Dumas, G.; Meidt, S.; Damas-Segovia, A.; Beck, R.; Murphy, E. J.; Mulcahy, D. D.; Groves, B.; Bolatto, A.; Dale, D.; Galametz, M.; Sandstrom, K.; Boquien, M.; Calzetti, D.; Kennicutt, R. C.; Hunt, L. K.; de Looze, I.; Pellegrini, E. W.

    2017-10-01

    The KINGFISH sample consists of 61 nearby galaxies of different morphological types. From this sample, we selected all galaxies with declinations >=-21° and named this subsample KINGFISHER (KINGFISH galaxies Emitting in Radio). These galaxies can be observed with the Effelsberg 100m single-dish telescope to obtain global measurements of the radio continuum at 20cm, 6cm, and 3.6cm. The non-KINGFISH galaxy, M51, is also included in this study. We observed 35 of these galaxies at 6cm, 10 galaxies at 20cm, and 7 at 3.6cm to complete already existing archival data during four observation runs (2008 Dec, 2009 Dec, 2010 Apr and 2010 Dec & 2012 Mar). (3 data files).

  10. Communicating Science for Impact: Radio for Reaching Farmers ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Radio to share results The project will translate research results into simple radio campaign messages targeting small-scale farmers. Researchers will test ... The project will assess the effect of radio campaigns in influencing adoption decisions among listeners. Farm Radio ... Agent(e) responsable du CRDI. crmadm CRM ...

  11. 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 services...

  12. 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...

  13. 49 CFR 220.23 - Publication of radio information.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Publication of radio information. 220.23 Section... § 220.23 Publication of radio information. Each railroad shall designate where radio base stations are.... The publication shall indicate the periods during which base and wayside radio stations are...

  14. The Importance of Site Selection for Radio Astronomy

    International Nuclear Information System (INIS)

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

    2014-01-01

    Radio sources are very weak since this object travel very far from outer space. Radio astronomy studies are limited due to radio frequency interference (RFI) that is made by man. If the harassment is not stopped, it will provide critical problems in their radio astronomy scientists research. The purpose of this study is to provide RFI map Peninsular Malaysia with a minimum mapping techniques RFI interference. RFI mapping technique using GIS is proposed as a tool in mapping techniques. Decision-making process for the selection requires gathering information from a variety of parameters. These factors affecting the selection process are also taken account. In this study, various factors or parameters involved such as availability of telecommunications transmission (including radio and television), rainfall, water line and human activity. This study will benefit radio astronomy research especially in the RFI profile in Malaysia. Keywords: Radio Astronomy, Radio Frequency Interference (RFI), RFI mapping technique : GIS

  15. Millisecond radio pulsars in globular clusters

    Science.gov (United States)

    Verbunt, Frank; Lewin, Walter H. G.; Van Paradijs, Jan

    1989-01-01

    It is shown that the number of millisecond radio pulsars, in globular clusters, should be larger than 100, applying the standard scenario that all the pulsars descend from low-mass X-ray binaries. Moreover, most of the pulsars are located in a small number of clusters. The prediction that Teran 5 and Liller 1 contain at least about a dozen millisecond radio pulsars each is made. The observations of millisecond radio pulsars in globular clusters to date, in particular the discovery of two millisecond radio pulsars in 47 Tuc, are in agreement with the standard scenario, in which the neutron star is spun up during the mass transfer phase.

  16. UNDERSTANDING THE EVOLUTION OF CLOSE BINARY SYSTEMS WITH RADIO PULSARS

    Energy Technology Data Exchange (ETDEWEB)

    Benvenuto, O. G. [Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata, 1900 La Plata, Buenos Aires (Argentina); De Vito, M. A. [Instituto de Astrofísica de La Plata (IALP), CCT-CONICET-UNLP. Paseo del Bosque S/N (B1900FWA), La Plata (Argentina); Horvath, J. E., E-mail: obenvenu@fcaglp.unlp.edu.ar, E-mail: adevito@fcaglp.unlp.edu.ar, E-mail: foton@astro.iag.usp.br [Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Universidade de São Paulo R. do Matão 1226 (05508-090), Cidade Universitária, São Paulo SP (Brazil)

    2014-05-01

    We calculate the evolution of close binary systems (CBSs) formed by a neutron star (behaving as a radio pulsar) and a normal donor star, which evolve either to a helium white dwarf (HeWD) or to ultra-short orbital period systems. We consider X-ray irradiation feedback and evaporation due to radio pulsar irradiation. We show that irradiation feedback leads to cyclic mass transfer episodes, allowing CBSs to be observed in between episodes as binary radio pulsars under conditions in which standard, non-irradiated models predict the occurrence of a low-mass X-ray binary. This behavior accounts for the existence of a family of eclipsing binary systems known as redbacks. We predict that redback companions should almost fill their Roche lobe, as observed in PSR J1723-2837. This state is also possible for systems evolving with larger orbital periods. Therefore, binary radio pulsars with companion star masses usually interpreted as larger than expected to produce HeWDs may also result in such quasi-Roche lobe overflow states, rather than hosting a carbon-oxygen WD. We found that CBSs with initial orbital periods of P{sub i} < 1 day evolve into redbacks. Some of them produce low-mass HeWDs, and a subgroup with shorter P{sub i} becomes black widows (BWs). Thus, BWs descend from redbacks, although not all redbacks evolve into BWs. There is mounting observational evidence favoring BW pulsars to be very massive (≳ 2 M {sub ☉}). As they should be redback descendants, redback pulsars should also be very massive, since most of the mass is transferred before this stage.

  17. DEEP SPITZER OBSERVATIONS OF INFRARED-FAINT RADIO SOURCES: HIGH-REDSHIFT RADIO-LOUD ACTIVE GALACTIC NUCLEI?

    International Nuclear Information System (INIS)

    Norris, Ray P.; Mao, Minnie; Afonso, Jose; Cava, Antonio; Farrah, Duncan; Oliver, Seb; Huynh, Minh T.; Mauduit, Jean-Christophe; Surace, Jason; Ivison, R. J.; Jarvis, Matt; Lacy, Mark; Maraston, Claudia; Middelberg, Enno; Seymour, Nick

    2011-01-01

    Infrared-faint radio sources (IFRSs) are a rare class of objects which are relatively bright at radio wavelengths but very faint at infrared and optical wavelengths. Here we present sensitive near-infrared observations of a sample of these sources taken as part of the Spitzer Extragalactic Representative Volume Survey. Nearly all the IFRSs are undetected at a level of ∼1 μJy in these new deep observations, and even the detections are consistent with confusion with unrelated galaxies. A stacked image implies that the median flux density is S 3.6μm ∼ 0.2 μJy or less, giving extreme values of the radio-infrared flux density ratio. Comparison of these objects with known classes of object suggests that the majority are probably high-redshift radio-loud galaxies, possibly suffering from significant dust extinction.

  18. Exploring Community Radio Programming Practices to Inform ...

    African Journals Online (AJOL)

    A collective case study (multi-site) design was used to probe educational programming practices used in community radio. The paper explores how community radio station programming engages listeners in community generated education programmes that are produced through collaborative work with radio listener clubs.

  19. Politics and Radio in the 1924 Campaign.

    Science.gov (United States)

    Berkman, Dave

    1987-01-01

    Discusses the relation between radio broadcasting and politics in the 1924 presidential campaign, focusing on newspaper and magazine coverage. Notes radio's influence on candidate image, the aspect of censorship, and the use of radio during the campaign and after the election. (MM)

  20. A Sensitive Secondary Users Selection Algorithm for Cognitive Radio Ad Hoc Networks

    Directory of Open Access Journals (Sweden)

    Aohan Li

    2016-03-01

    Full Text Available Secondary Users (SUs are allowed to use the temporarily unused licensed spectrum without disturbing Primary Users (PUs in Cognitive Radio Ad Hoc Networks (CRAHNs. Existing architectures for CRAHNs impose energy-consuming Cognitive Radios (CRs on SUs. However, the advanced CRs will increase energy cost for their cognitive functionalities, which is undesirable for the battery powered devices. A new architecture referred to as spectral Requirement-based CRAHN (RCRAHN is proposed to enhance energy efficiency for CRAHNs in this paper. In RCRAHNs, only parts of SUs are equipped with CRs. SUs equipped with CRs are referred to as Cognitive Radio Users (CRUs. To further enhance energy efficiency of CRAHNs, we aim to select minimum CRUs to sense available spectrum. A non-linear programming problem is mathematically formulated under the constraints of energy efficiency and real-time. Considering the NP-hardness of the problem, a framework of a heuristic algorithm referred to as Sensitive Secondary Users Selection (SSUS was designed to compute the near-optimal solutions. The simulation results demonstrate that SSUS not only improves the energy efficiency, but also achieves satisfied performances in end-to-end delay and communication reliability.

  1. A Sensitive Secondary Users Selection Algorithm for Cognitive Radio Ad Hoc Networks.

    Science.gov (United States)

    Li, Aohan; Han, Guangjie; Wan, Liangtian; Shu, Lei

    2016-03-26

    Secondary Users (SUs) are allowed to use the temporarily unused licensed spectrum without disturbing Primary Users (PUs) in Cognitive Radio Ad Hoc Networks (CRAHNs). Existing architectures for CRAHNs impose energy-consuming Cognitive Radios (CRs) on SUs. However, the advanced CRs will increase energy cost for their cognitive functionalities, which is undesirable for the battery powered devices. A new architecture referred to as spectral Requirement-based CRAHN (RCRAHN) is proposed to enhance energy efficiency for CRAHNs in this paper. In RCRAHNs, only parts of SUs are equipped with CRs. SUs equipped with CRs are referred to as Cognitive Radio Users (CRUs). To further enhance energy efficiency of CRAHNs, we aim to select minimum CRUs to sense available spectrum. A non-linear programming problem is mathematically formulated under the constraints of energy efficiency and real-time. Considering the NP-hardness of the problem, a framework of a heuristic algorithm referred to as Sensitive Secondary Users Selection (SSUS) was designed to compute the near-optimal solutions. The simulation results demonstrate that SSUS not only improves the energy efficiency, but also achieves satisfied performances in end-to-end delay and communication reliability.

  2. 47 CFR 2.815 - External radio frequency power amplifiers.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false External radio frequency power amplifiers. 2... AND RADIO TREATY MATTERS; GENERAL RULES AND REGULATIONS Marketing of Radio-frequency Devices § 2.815 External radio frequency power amplifiers. (a) As used in this part, an external radio frequency power...

  3. 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.

  4. Interferometry and synthesis in radio astronomy

    CERN Document Server

    Thompson, A Richard; Swenson Jr , George W

    2017-01-01

    This book is open access under a CC BY-NC 4.0 license. The third edition of this indispensable book in radio interferometry provides extensive updates to the second edition, including results and technical advances from the past decade; discussion of arrays that now span the full range of the radio part of the electromagnetic spectrum observable from the ground, 10 MHz to 1 THz; an analysis of factors that affect array speed; and an expanded discussion of digital signal-processing techniques and of scintillation phenomena and the effects of atmospheric water vapor on image distortion, among many other topics. With its comprehensiveness and detailed exposition of all aspects of the theory and practice of radio interferometry and synthesis imaging, this book has established itself as a standard reference in the field. It begins with an overview of the basic principles of radio astronomy, a short history of the development of radio interferometry, and an elementary discussion of the operation of an interferomete...

  5. A Survey of MAC Protocols for Cognitive Radio Body Area Networks.

    Science.gov (United States)

    Bhandari, Sabin; Moh, Sangman

    2015-04-20

    The advancement in electronics, wireless communications and integrated circuits has enabled the development of small low-power sensors and actuators that can be placed on, in or around the human body. A wireless body area network (WBAN) can be effectively used to deliver the sensory data to a central server, where it can be monitored, stored and analyzed. For more than a decade, cognitive radio (CR) technology has been widely adopted in wireless networks, as it utilizes the available spectra of licensed, as well as unlicensed bands. A cognitive radio body area network (CRBAN) is a CR-enabled WBAN. Unlike other wireless networks, CRBANs have specific requirements, such as being able to automatically sense their environments and to utilize unused, licensed spectra without interfering with licensed users, but existing protocols cannot fulfill them. In particular, the medium access control (MAC) layer plays a key role in cognitive radio functions, such as channel sensing, resource allocation, spectrum mobility and spectrum sharing. To address various application-specific requirements in CRBANs, several MAC protocols have been proposed in the literature. In this paper, we survey MAC protocols for CRBANs. We then compare the different MAC protocols with one another and discuss challenging open issues in the relevant research.

  6. Equal gain combining for cooperative spectrum sensing in cognitive radio networks

    KAUST Repository

    Hamza, Doha R.

    2014-08-01

    Sensing with equal gain combining (SEGC), a novel cooperative spectrum sensing technique for cognitive radio networks, is proposed. Cognitive radios simultaneously transmit their sensing results to the fusion center (FC) over multipath fading reporting channels. The cognitive radios estimate the phases of the reporting channels and use those estimates for coherent combining of the sensing results at the FC. A global decision is made at the FC by comparing the received signal with a threshold. We obtain the global detection probabilities and secondary throughput exactly through a moment generating function approach. We verify our solution via system simulation and demonstrate that the Chernoff bound and central limit theory approximation are not tight. The cases of hard sensing and soft sensing are considered and we provide examples in which hard sensing is advantageous to soft sensing. We contrast the performance of SEGC with maximum ratio combining of the sensors\\' results and provide examples where the former is superior. Furthermore, we evaluate the performance of SEGC against existing orthogonal reporting techniques such as time division multiple access (TDMA). SEGC performance always dominates that of TDMA in terms of secondary throughput. We also study the impact of phase and synchronization errors and demonstrate the robustness of the SEGC technique against such imperfections. © 2002-2012 IEEE.

  7. Virtual observatory tools and amateur radio observations supporting scientific analysis of Jupiter radio emissions

    Science.gov (United States)

    Cecconi, Baptiste; Hess, Sebastien; Le Sidaner, Pierre; Savalle, Renaud; Stéphane, Erard; Coffre, Andrée; Thétas, Emmanuel; André, Nicolas; Génot, Vincent; Thieman, Jim; Typinski, Dave; Sky, Jim; Higgins, Chuck; Imai, Masafumi

    2016-04-01

    In the frame of the preparation of the NASA/JUNO and ESA/JUICE (Jupiter Icy Moon Explorer) missions, and the development of a planetary sciences virtual observatory (VO), we are proposing a new set of tools directed to data providers as well as users, in order to ease data sharing and discovery. We will focus on ground based planetary radio observations (thus mainly Jupiter radio emissions), trying for instance to enhance the temporal coverage of jovian decametric emission. The data service we will be using is EPN-TAP, a planetary science data access protocol developed by Europlanet-VESPA (Virtual European Solar and Planetary Access). This protocol is derived from IVOA (International Virtual Observatory Alliance) standards. The Jupiter Routine Observations from the Nancay Decameter Array are already shared on the planetary science VO using this protocol, as well as data from the Iitate Low Frquency Radio Antenna, in Japan. Amateur radio data from the RadioJOVE project is also available. The attached figure shows data from those three providers. We will first introduce the VO tools and concepts of interest for the planetary radioastronomy community. We will then present the various data formats now used for such data services, as well as their associated metadata. We will finally show various prototypical tools that make use of this shared datasets.

  8. Formation of Radio Type II Bursts During a Multiple Coronal Mass Ejection Event

    Science.gov (United States)

    Al-Hamadani, Firas; Pohjolainen, Silja; Valtonen, Eino

    2017-12-01

    We study the solar event on 27 September 2001 that consisted of three consecutive coronal mass ejections (CMEs) originating from the same active region, which were associated with several periods of radio type II burst emission at decameter-hectometer (DH) wavelengths. Our analysis shows that the first radio burst originated from a low-density environment, formed in the wake of the first, slow CME. The frequency-drift of the burst suggests a low-speed burst driver, or that the shock was not propagating along the large density gradient. There is also evidence of band-splitting within this emission lane. The origin of the first shock remains unclear, as several alternative scenarios exist. The second shock showed separate periods of enhanced radio emission. This shock could have originated from a CME bow shock, caused by the fast and accelerating second or third CME. However, a shock at CME flanks is also possible, as the density depletion caused by the three CMEs would have affected the emission frequencies and hence the radio source heights could have been lower than usual. The last type II burst period showed enhanced emission in a wider bandwidth, which was most probably due to the CME-CME interaction. Only one shock that could reliably be associated with the investigated CMEs was observed to arrive near Earth.

  9. Magnetogasdynamics of double radio sources

    International Nuclear Information System (INIS)

    Nepveu, M.

    1979-01-01

    The magnetogasdynamical behaviour of plasmoids moving through an ambient gas is investigated numerically with a two-dimensional code, based on the SHASTA scheme. The astrophysical importance of this study lies in the observed extended extragalactic radio sources. It is assumed that plasma clouds with cylinder symmetry are ejected from the nucleus of a galaxy. Their large-scale evolution in the intergalactic medium (IGM) is followed. The gas dynamics of an ejected cloud, the magnetogasdynamics of ejected clouds, the Christiansen-Pacholczyk-Scott picture for radio galaxies and the shear layers in double radio sources are studied. (Auth.)

  10. FR-type radio sources in COSMOS: relation of radio structure to size, accretion modes and large-scale environment

    Science.gov (United States)

    Vardoulaki, Eleni; Faustino Jimenez Andrade, Eric; Delvecchio, Ivan; Karim, Alexander; Smolčić, Vernesa; Magnelli, Benjamin; Bertoldi, Frank; Schinnener, Eva; Sargent, Mark; Finoguenov, Alexis; VLA COSMOS Team

    2018-01-01

    The radio sources associated with active galactic nuclei (AGN) can exhibit a variety of radio structures, from simple to more complex, giving rise to a variety of classification schemes. The question which still remains open, given deeper surveys revealing new populations of radio sources, is whether this plethora of radio structures can be attributed to the physical properties of the host or to the environment. Here we present an analysis on the radio structure of radio-selected AGN from the VLA-COSMOS Large Project at 3 GHz (JVLA-COSMOS; Smolčić et al.) in relation to: 1) their linear projected size, 2) the Eddington ratio, and 3) the environment their hosts lie within. We classify these as FRI (jet-like) and FRII (lobe-like) based on the FR-type classification scheme, and compare them to a sample of jet-less radio AGN in JVLA-COSMOS. We measure their linear projected sizes using a semi-automatic machine learning technique. Their Eddington ratios are calculated from X-ray data available for COSMOS. As environmental probes we take the X-ray groups (hundreds kpc) and the density fields (~Mpc-scale) in COSMOS. We find that FRII radio sources are on average larger than FRIs, which agrees with literature. But contrary to past studies, we find no dichotomy in FR objects in JVLA-COSMOS given their Eddington ratios, as on average they exhibit similar values. Furthermore our results show that the large-scale environment does not explain the observed dichotomy in lobe- and jet-like FR-type objects as both types are found on similar environments, but it does affect the shape of the radio structure introducing bents for objects closer to the centre of an X-ray group.

  11. The Diffusion and Impact of Radio Frequency Identification in Supply Chains: A Multi-Method Approach

    Science.gov (United States)

    Wu, Xiaoran

    2012-01-01

    As a promising and emerging technology for supply chain management, Radio Frequency Identification (RFID) is a new alternative to existing tracking technologies and also allows a range of internal control and supply chain coordination. RFID has generated a significant amount of interest and activities from both practitioners and researchers in…

  12. Population Studies of Radio and Gamma-Ray Pulsars

    Science.gov (United States)

    Harding, Alice K; Gonthier, Peter; Coltisor, Stefan

    2004-01-01

    Rotation-powered pulsars are one of the most promising candidates for at least some of the 40-50 EGRET unidentified gamma-ray sources that lie near the Galactic plane. Since the end of the EGRO mission, the more sensitive Parkes Multibeam radio survey has detected mere than two dozen new radio pulsars in or near unidentified EGRET sources, many of which are young and energetic. These results raise an important question about the nature of radio quiescence in gamma-ray pulsars: is the non-detection of radio emission a matter of beaming or of sensitivity? The answer is very dependent on the geometry of the radio and gamma-ray beams. We present results of a population synthesis of pulsars in the Galaxy, including for the first time the full geometry of the radio and gamma-ray beams. We use a recent empirically derived model of the radio emission and luminosity, and a gamma-ray emission geometry and luminosity derived theoretically from pair cascades in the polar slot gap. The simulation includes characteristics of eight radio surveys of the Princeton catalog plus the Parkes MB survey. Our results indicate that EGRET was capable of detecting several dozen pulsars as point sources, with the ratio of radio-loud to radio-quiet gamma-ray pulsars increasing significantly to about ten to one when the Parkes Survey is included. Polar cap models thus predict that many of the unidentified EGRET sources could be radio-loud gamma- ray pulsars, previously undetected as radio pulsars due to distance, large dispersion and lack of sensitivity. If true, this would make gamma-ray telescopes a potentially more sensitive tool for detecting distant young neutron stars in the Galactic plane.

  13. The collective radio properties of symbiotic stars

    International Nuclear Information System (INIS)

    Seaquist, E.R.; Taylor, A.R.

    1990-01-01

    Radio measurements of symbiotic stars are reported which extend the search for radio emission and provide multifrequency and multiepoch measurements of previously detected stars. The results show no evidence that there are time variations in excess of about 30 percent over a period of several years in the detected stars. The radio flux densities are correlated with brightness in the IR, especially at the longer IR wavelengths where dust emission dominates. It is confirmed that symbiotics with the latest red giant spectral types are the most luminous radio emitters. The D-types are the most radio-luminous. Virtually all detected stars with measurements at more than one frequency exhibit a positive spectral index, consistent with optically thick thermal bremsstrahlung. The binary separation for a number of radio-emitting symbiotics is estimated, and it is found that the distribution of inferred binary separations is dramatically different for IR D-types than for S-types. 37 refs

  14. Radio-flaring Ultracool Dwarf Population Synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Route, Matthew, E-mail: mroute@purdue.edu [Department of Astronomy and Astrophysics, the Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States)

    2017-08-10

    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 (<25 pc away) have been discovered. I discuss a number of scenarios that may explain this 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.

  15. Radio Loud AGN Unification: Connecting Jets and Accretion

    Directory of Open Access Journals (Sweden)

    Meyer Eileen T.

    2013-12-01

    Full Text Available While only a fraction of Active Galactic Nuclei are observed to host a powerful relativistic jet, a cohesive picture is emerging that radio-loud AGN may represent an important phase in the evolution of galaxies and the growth of the central super-massive black hole. I will review my own recent observational work in radio-loud AGN unification in the context of understanding how and why jets form and their the connection to different kinds of accretion and growing the black hole, along with a brief discussion of possible connections to recent modeling work in jet formation. Starting from the significant observational advances in our understanding of jetted AGN as a population over the last decade thanks to new, more sensitive instruments such as Fermi and Swift as well as all-sky surveys at all frequencies, I will lay out the case for a dichotomy in the jetted AGN population connected to accretion mode onto the black hole. In recent work, we have identified two sub-populations of radio-loud AGN which appear to be distinguished by jet structure, where low-efficiency accreting systems produce ‘weak’ jets which decelerate more rapidly than the ’strong’ jets of black holes accreting near the Eddington limit. The two classes are comprised of: (1The weak jet sources, corresponding to the less collimated, edge-darkened FR Is, with a decelerating or spine-sheath jet with velocity gradients, and (2 The strong jet sources, having fast, collimated jets, and typically displaying strong emission lines. The dichotomy in the vp-Lp plane can be understood as a "broken power sequence" in which jets exist on one branch or the other based on the particular accretion mode (Georganopolous 2011.We suggest that the intrinsic kinetic power (as measured by low-frequency, isotropic radio emission, the orientation, and the accretion rate of the SMBH system are the the fundamental axes needed for unification of radio-loud AGN by studying a well-characterized sample

  16. Cost-effectiveness of one versus two sample faecal immunochemical testing for colorectal cancer screening.

    Science.gov (United States)

    Goede, S Lucas; van Roon, Aafke H C; Reijerink, Jacqueline C I Y; van Vuuren, Anneke J; Lansdorp-Vogelaar, Iris; Habbema, J Dik F; Kuipers, Ernst J; van Leerdam, Monique E; van Ballegooijen, Marjolein

    2013-05-01

    The sensitivity and specificity of a single faecal immunochemical test (FIT) are limited. The performance of FIT screening can be improved by increasing the screening frequency or by providing more than one sample in each screening round. This study aimed to evaluate if two-sample FIT screening is cost-effective compared with one-sample FIT. The MISCAN-colon microsimulation model was used to estimate costs and benefits of strategies with either one or two-sample FIT screening. The FIT cut-off level varied between 50 and 200 ng haemoglobin/ml, and the screening schedule was varied with respect to age range and interval. In addition, different definitions for positivity of the two-sample FIT were considered: at least one positive sample, two positive samples, or the mean of both samples being positive. Within an exemplary screening strategy, biennial FIT from the age of 55-75 years, one-sample FIT provided 76.0-97.0 life-years gained (LYG) per 1000 individuals, at a cost of € 259,000-264,000 (range reflects different FIT cut-off levels). Two-sample FIT screening with at least one sample being positive provided 7.3-12.4 additional LYG compared with one-sample FIT at an extra cost of € 50,000-59,000. However, when all screening intervals and age ranges were considered, intensifying screening with one-sample FIT provided equal or more LYG at lower costs compared with two-sample FIT. If attendance to screening does not differ between strategies it is recommended to increase the number of screening rounds with one-sample FIT screening, before considering increasing the number of FIT samples provided per screening round.

  17. A COTS RF Optical Software Defined Radio for the Integrated Radio and Optical Communications Test Bed

    Science.gov (United States)

    Nappier, Jennifer M.; Zeleznikar, Daniel J.; Wroblewski, Adam C.; Tokars, Roger P.; Schoenholz, Bryan L.; Lantz, Nicholas C.

    2016-01-01

    The Integrated Radio and Optical Communications (iROC) project at the National Aeronautics and Space Administration (NASA) is investigating the merits of a hybrid radio frequency (RF) and optical communication system for deep space missions. In an effort to demonstrate the feasibility and advantages of a hybrid RFOptical software defined radio (SDR), a laboratory prototype was assembled from primarily commercial-off-the-shelf (COTS) hardware components. This COTS platform has been used to demonstrate simultaneous transmission of the radio and optical communications waveforms through to the physical layer (telescope and antenna). This paper details the hardware and software used in the platform and various measures of its performance. A laboratory optical receiver platform has also been assembled in order to demonstrate hybrid free space links in combination with the transmitter.

  18. A COTS RF/Optical Software Defined Radio for the Integrated Radio and Optical Communications Test Bed

    Science.gov (United States)

    Nappier, Jennifer M.; Zeleznikar, Daniel J.; Wroblewski, Adam C.; Tokars, Roger P.; Schoenholz, Bryan L.; Lantz, Nicholas C.

    2017-01-01

    The Integrated Radio and Optical Communications (iROC) project at the National Aeronautics and Space Administration (NASA) is investigating the merits of a hybrid radio frequency (RF) and optical communication system for deep space missions. In an effort to demonstrate the feasibility and advantages of a hybrid RF/Optical software defined radio (SDR), a laboratory prototype was assembled from primarily commercial-off-the-shelf (COTS) hardware components. This COTS platform has been used to demonstrate simultaneous transmission of the radio and optical communications waveforms through to the physical layer (telescope and antenna). This paper details the hardware and software used in the platform and various measures of its performance. A laboratory optical receiver platform has also been assembled in order to demonstrate hybrid free space links in combination with the transmitter.

  19. Meteor trajectory estimation from radio meteor observations

    Science.gov (United States)

    Kákona, J.

    2016-01-01

    Radio meteor observation techniques are generally accepted as meteor counting methods useful mainly for meteor flux detection. Due to the technical progress in radio engineering and electronics a construction of a radio meteor detection network with software defined receivers has become possible. These receivers could be precisely time synchronized and could obtain data which provide us with more information than just the meteor count. We present a technique which is able to compute a meteor trajectory from the data recorded by multiple radio stations.

  20. THE SPITZER HIGH-REDSHIFT RADIO GALAXY SURVEY

    International Nuclear Information System (INIS)

    De Breuck, Carlos; Galametz, Audrey; Vernet, Joel; Seymour, Nick; Stern, Daniel; Eisenhardt, P. R. M.; Willner, S. P.; Fazio, G. G.; Lacy, Mark; Rettura, Alessandro; Rocca-Volmerange, Brigitte

    2010-01-01

    We present results from a comprehensive imaging survey of 70 radio galaxies at redshifts 1 3 μ m /S 1.6 μ m versus S 5 μ m /S 3 μ m criterion, we identify 42 sources where the rest-frame 1.6 μm emission from the stellar population can be measured. For these radio galaxies, the median stellar mass is high, 2 x 10 11 M sun , and remarkably constant within the range 1 3, there is tentative evidence for a factor of two decrease in stellar mass. This suggests that radio galaxies have assembled the bulk of their stellar mass by z ∼ 3, but confirmation by more detailed decomposition of stellar and active galactic nucleus (AGN) emission is needed. The rest-frame 500 MHz radio luminosities are only marginally correlated with stellar mass but are strongly correlated with the rest-frame 5 μm hot dust luminosity. This suggests that the radio galaxies have a large range of Eddington ratios. We also present new Very Large Array 4.86 and 8.46 GHz imaging of 14 radio galaxies and find that radio core dominance-an indicator of jet orientation-is strongly correlated with hot dust luminosity. While all of our targets were selected as narrow-lined, type 2 AGNs, this result can be understood in the context of orientation-dependent models if there is a continuous distribution of orientations from obscured type 2 to unobscured type 1 AGNs rather than a clear dichotomy. Finally, four radio galaxies have nearby (<6'') companions whose mid-IR colors are suggestive of their being AGNs. This may indicate an association between radio galaxy activity and major mergers.

  1. Observations of radio sources or 'What happened to radio stars?'

    International Nuclear Information System (INIS)

    Conway, R.G.

    1988-01-01

    A review is given of the early history of the interpretation of the radiation mechanisms following the discovery of the discrete radio sources, both galactic and extragalactic. The conflicting views which prevailed in the early fifties are discussed in some detail: some advocated thermal radiation from stars relatively close by, and others proposed the alternative that synchrotron radiation was responsible for the majority of the radio sources. Attention is drawn to the importance of high-resolution interferometry, whereby the structure of many of the sources could be obtained. Red-shift measurements and spectral distributions also played a part in determining distances and flux strengths at the sources. (U.K.)

  2. On the TDD Subframe Structure for Beyond 4G Radio Access Network

    DEFF Research Database (Denmark)

    Lähetkangas, Eeva; Pajukoski, Kari; Tiirola, Esa

    2013-01-01

    The purpose of a Beyond 4G (B4G) radio access technology, is to cope with the expected exponential increase of mobile data traffic in local area (LA). The requirements related to physical layer control signaling latencies and to hybrid ARQ (HARQ) round trip time (RTT) are in the order of ~1ms...... requirement and significant control signaling latency reductions compared to existing LTE-Advanced and WiMAX technologies....

  3. Radio as the Voice of God: Peace and Tolerance Radio Programming’s Impact on Norms

    Directory of Open Access Journals (Sweden)

    Daniel P. Aldrich

    2012-12-01

    Full Text Available Observers have argued that radio programming can alter norms, especially through hate radio designed to increase animosity between groups. This article tests whether or not radio programming under the Countering Violent Extremism (CVE policy framework can reduce potential conflict and increase civic engagement and positive views of foreign nations. Data from surveys of more than 1,000 respondents in Mali, Chad, and Niger illuminate the ways in which peace and tolerance programming changed perspectives and altered behavior in statistically significant ways. Results show that individuals exposed to multi-level U.S. government programming were more likely to listen to peace and tolerance radio. Further, bivariate, multivariate regression, and propensity score matching techniques show that individuals who listened more regularly to such programs participated more frequently in civic activities and supported working with the West to combat terrorism (holding constant a number of potential confounding economic, demographic, and attitudinal factors. However, higher levels of radio listening had no measurable impact on opposition to the use of violence in the name of Islam or opposition to the imposition of Islamic law. Further, data indicate that women and men have responded to programming in measurably different ways. These mixed results have important implications for current and future “soft-side” programs for countering violent extremism.

  4. Hardware Interface Description for the Integrated Power, Avionics, and Software (iPAS) Space Telecommunications Radio Ssystem (STRS) Radio

    Science.gov (United States)

    Shalkhauser, Mary Jo W.; Roche, Rigoberto

    2017-01-01

    The Space Telecommunications Radio System (STRS) provides a common, consistent framework for software defined radios (SDRs) to abstract the application software from the radio platform hardware. The STRS standard aims to reduce the cost and risk of using complex, configurable and reprogrammable radio systems across NASA missions. To promote the use of the STRS architecture for future NASA advanced exploration missions, NASA Glenn Research Center (GRC) developed an STRS-compliant SDR on a radio platform used by the Advance Exploration System program at the Johnson Space Center (JSC) in their Integrated Power, Avionics, and Software (iPAS) laboratory. The iPAS STRS Radio was implemented on the Reconfigurable, Intelligently-Adaptive Communication System (RIACS) platform, currently being used for radio development at JSC. The platform consists of a Xilinx ML605 Virtex-6 FPGA board, an Analog Devices FMCOMMS1-EBZ RF transceiver board, and an Embedded PC (Axiomtek eBox 620-110-FL) running the Ubuntu 12.4 operating system. Figure 1 shows the RIACS platform hardware. The result of this development is a very low cost STRS compliant platform that can be used for waveform developments for multiple applications.The purpose of this document is to describe how to develop a new waveform using the RIACS platform and the Very High Speed Integrated Circuits (VHSIC) Hardware Description Language (VHDL) FPGA wrapper code and the STRS implementation on the Axiomtek processor.

  5. Waveform Developer's Guide for the Integrated Power, Avionics, and Software (iPAS) Space Telecommunications Radio System (STRS) Radio

    Science.gov (United States)

    Shalkhauser, Mary Jo W.; Roche, Rigoberto

    2017-01-01

    The Space Telecommunications Radio System (STRS) provides a common, consistent framework for software defined radios (SDRs) to abstract the application software from the radio platform hardware. The STRS standard aims to reduce the cost and risk of using complex, configurable and reprogrammable radio systems across NASA missions. To promote the use of the STRS architecture for future NASA advanced exploration missions, NASA Glenn Research Center (GRC) developed an STRS-compliant SDR on a radio platform used by the Advance Exploration System program at the Johnson Space Center (JSC) in their Integrated Power, Avionics, and Software (iPAS) laboratory. The iPAS STRS Radio was implemented on the Reconfigurable, Intelligently-Adaptive Communication System (RIACS) platform, currently being used for radio development at JSC. The platform consists of a Xilinx(Trademark) ML605 Virtex(Trademark)-6 FPGA board, an Analog Devices FMCOMMS1-EBZ RF transceiver board, and an Embedded PC (Axiomtek(Trademark) eBox 620-110-FL) running the Ubuntu 12.4 operating system. The result of this development is a very low cost STRS compliant platform that can be used for waveform developments for multiple applications. The purpose of this document is to describe how to develop a new waveform using the RIACS platform and the Very High Speed Integrated Circuits (VHSIC) Hardware Description Language (VHDL) FPGA wrapper code and the STRS implementation on the Axiomtek processor.

  6. Tuning in to pavement radio

    NARCIS (Netherlands)

    Ellis, S.

    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,

  7. TURBULENCE AND RADIO MINI-HALOS IN THE SLOSHING CORES OF GALAXY CLUSTERS

    International Nuclear Information System (INIS)

    ZuHone, J. A.; Markevitch, M.; Brunetti, G.; Giacintucci, S.

    2013-01-01

    A number of relaxed, cool-core galaxy clusters exhibit diffuse, steep-spectrum radio sources in their central regions, known as radio mini-halos. It has been proposed that the relativistic electrons responsible for the emission have been reaccelerated by turbulence generated by the sloshing of the cool core gas. We present a high-resolution MHD simulation of gas sloshing in a galaxy cluster coupled with subgrid simulations of relativistic electron acceleration to test this hypothesis. Our simulation shows that the sloshing motions generate turbulence on the order of δv ∼ 50-200 km s –1 on spatial scales of ∼50-100 kpc and below in the cool core region within the envelope of the sloshing cold fronts, whereas outside the cold fronts, there is negligible turbulence. This turbulence is potentially strong enough to reaccelerate relativistic electron seeds (with initial γ ∼ 100-500) to γ ∼ 10 4 via damping of magnetosonic waves and non-resonant compression. The seed electrons could remain in the cluster from, e.g., past active galactic nucleus activity. In combination with the magnetic field amplification in the core, these electrons then produce diffuse radio synchrotron emission that is coincident with the region bounded by the sloshing cold fronts, as indeed observed in X-rays and the radio. The result holds for different initial spatial distributions of pre-existing relativistic electrons. The power and the steep spectral index (α ≈ 1-2) of the resulting radio emission are consistent with observations of mini-halos, though the theoretical uncertainties of the acceleration mechanisms are high. We also produce simulated maps of inverse-Compton hard X-ray emission from the same population of relativistic electrons.

  8. 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.

  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. Radio protocols for LTE and LTE-advanced

    CERN Document Server

    Yi, SeungJune; Lee, YoungDae; Park, SungJun; Jung, SungHoon

    2012-01-01

    Provides a unique focus on radio protocols for LTE and LTE-Advanced (LTE-A) Giving readers a valuable understanding of LTE radio protocols, this book covers LTE (Long-Term Evolution) Layer 2/3 radio protocols as well as new features including LTE-Advanced. It is divided into two sections to differentiate between the two technologies' characteristics. The authors systematically explain the design principles and functions of LTE radio protocols during the development of mobile handsets. The book also provides essential knowledge on the interaction between mobile networks a

  11. ¿Radios Comunitarias?

    OpenAIRE

    José Ignacio López Vigil

    2015-01-01

    Varias han sido las denominaciones dadas a la radio cuando su proyecto está al servicio de la gente. Palabras apropiadas pero devaluadas al decir del autor, a las que ahora se suma otras radios ciudadanas. Ciudadana para relievarla como ejercicio de poder y espacio de verdadera participación de la gente en la vida de su nación. Ciudadanos son los que piensan con cabeza propia y pesan en la opinión pública. Presenta una sinopsis de la historia de éstas desde 1974. Señala que la competencia obl...

  12. Radio frequency selective addressing of localized atoms in a periodic potential

    International Nuclear Information System (INIS)

    Ott, H.; De Mirandes, E.; Ferlaino, F.; Roati, G.; Tuerck, V.; Modugno, G.; Inguscio, M.

    2004-01-01

    We study the localization and addressability of ultracold atoms in a combined parabolic and periodic potential. Such a potential supports the existence of localized stationary states and we show that applying a radio frequency field allows us to selectively address atoms in these states. This method is used to measure the energy and momentum distribution of the atoms in the localized states. We also discuss possible extensions of this scheme to address and manipulate atoms in single lattice sites

  13. Launch Will Create a Radio Telescope Larger than Earth

    Science.gov (United States)

    . This includes the National Science Foundation's Very Long Baseline Array (VLBA), an array of 10 telescopes spanning the United States from Hawaii to Saint Croix; NASA's Deep Space Network (DSN) sites in California, Spain, and Australia; the European VLBI Network, more than a dozen telescopes ranging from the United Kingdom to China; a Southern Hemisphere array of telescopes stretching from eastern Australia to South Africa; and Japan's network of domestic radio telescopes. In the United States, NASA is funding critical roles in the VSOP mission at both JPL and NRAO. JPL has built an array of three new tracking stations at its DSN sites in Goldstone, CA; Madrid, Spain; and near Canberra, Australia. A large existing tracking station at each of these sites has also been converted to an extremely sensitive radio telescope for simultaneous observations with the satellite. JPL also is providing precision orbit determination, scientific and operational planning support to the Japanese, and advice to U.S. astronomers who wish to observe with the satellite. NRAO is building a new tracking station at Green Bank, WV; contributing observing time on the VLBA array of telescopes; modifying existing data analysis hardware and software, and aiding astronomers with the analysis of the VSOP data. Much of the observational data will be processed at NRAO's facility in Socorro, NM, using the VLBA Correlator, a special purpose high-performance computer designed to process VLBI data. VSOP is the culmination of many years of planning and work by scientists and engineers around the world. Tests using NASA's Tracking and Data Relay Satellite System (TDRSS) proved the feasibility of space VLBI in 1986. Just last year, those old data were used again to test successfully the data-reduction facilities for VSOP. JPL manages the U.S. Space Very Long Baseline Interferometry project for NASA's Office of Space Science, Washington, DC. The VLBA, headquartered in Socorro, NM, is part of the National Radio

  14. A Fast Radio Burst Host Galaxy

    OpenAIRE

    Keane, E. F.; Johnston, S.; Bhandari, S.; Barr, E.; Bhat, N. D. R.; Burgay, M.; Caleb, M.; Flynn, C.; Jameson, A.; Kramer, M.; Petroff, E.; Possenti, A.; van Straten, W.; Bailes, M.; Burke-Spolaor, S.

    2016-01-01

    In recent years, millisecond duration radio signals originating from distant galaxies appear to have been discovered in the so-called Fast Radio Bursts. These signals are dispersed according to a precise physical law and this dispersion is a key observable quantity which, in tandem with a redshift measurement, can be used for fundamental physical investigations. While every fast radio burst has a dispersion measurement, none before now have had a redshift measurement, due to the difficulty in...

  15. Uticaj transportnih protokola na efikasnost namenskih radio-komunikacija

    Directory of Open Access Journals (Sweden)

    Ljubiša S. Nedeljković

    2014-04-01

    Full Text Available Savremene namenske radio-komunikacije zasnivaju se na internet protokolu. Efikasnost namenskih radio-komunikacija zavisi od propusnosti. Na propusnost namenskih radio-komunikacija utiču i transportni protokoli. U radu je analizirana propusnost transportnih protokola TCP (Transport Control Protocol i UDP (User Datagram Protocol u VF (visoko frekvencijskim i VVF (vrlo visoko- frekvencijskim namenskim radio-komunikacijama sa očekivanim vremenima kašnjenja i verovatnoćom greške po paketu podataka. Ocenjena je mogućnost njihove primene u namenskim radio-komunikacijama. Pri tome je uzet u obzir uticaj sledećih faktora: vreme povratnog puta, veličina paketa podataka, veličina prozora i verovatnoća greške po paketu podataka. Transportni protokol sa većom propusnošću pogodniji je za primenu u namenskim radio-komunikacijama. Veća propusnost transportnih protokola znači da je veća i propusnost namenskih radio-komunikacija. 

  16. Shoestring Budget Radio Astronomy (Abstract)

    Science.gov (United States)

    Hoot, J. E.

    2017-12-01

    (Abstract only) 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.

  17. An Energy-Efficient Game-Theory-Based Spectrum Decision Scheme for Cognitive Radio Sensor Networks

    Directory of Open Access Journals (Sweden)

    Shelly Salim

    2016-06-01

    Full Text Available A cognitive radio sensor network (CRSN is a wireless sensor network in which sensor nodes are equipped with cognitive radio. In this paper, we propose an energy-efficient game-theory-based spectrum decision (EGSD scheme for CRSNs to prolong the network lifetime. Note that energy efficiency is the most important design consideration in CRSNs because it determines the network lifetime. The central part of the EGSD scheme consists of two spectrum selection algorithms: random selection and game-theory-based selection. The EGSD scheme also includes a clustering algorithm, spectrum characterization with a Markov chain, and cluster member coordination. Our performance study shows that EGSD outperforms the existing popular framework in terms of network lifetime and coordination overhead.

  18. Why is observable radio recombination line emission from galactic HII regions always close to LTE

    International Nuclear Information System (INIS)

    Shaver, P.A.

    1980-01-01

    There is no evidence for significant deviations from LTE in single-dish observations of radio recombination line emission from galactic HII regions. This is in agreement with the known properties of HII regions, particularly their density variations and limited range of excitation parameters; the optimum configuration for strong observable non-LTE effects, low electron density and high emission measure, simply does not exist in galactic HII regions, and the observed lines are emitted under near-LTE conditions. Models of the Orion Nebulae and NGC 6604 are presented which fit all available data and show only weak stimulated emission. It is concluded that reliable electron temperatures can indeed be obtained from straightforward analysis of appropriate radio recombination lines. (orig.)

  19. Community-Based Colorectal Cancer Screening in a Rural Population: Who Returns Fecal Immunochemical Test (FIT) Kits?

    Science.gov (United States)

    Crosby, Richard A; Stradtman, Lindsay; Collins, Tom; Vanderpool, Robin

    2017-09-01

    To determine the return rate of community-delivered fecal immunochemical test (FIT) kits in a rural population and to identify significant predictors of returning kits. Residents were recruited in 8 rural Kentucky counties to enroll in the study and receive an FIT kit. Of 345 recruited, 82.0% returned an FIT kit from the point of distribution. These participants were compared to the remainder relative to age, sex, marital status, having an annual income below $15,000, not graduating from high school, not having a regular health care provider, not having health care coverage, being a current smoker, indicating current overweight or obese status, and a scale measure of fatalism pertaining to colorectal cancer. Predictors achieving significance at the bivariate level were entered into a stepwise logistic regression model to calculate adjusted OR and 95% CI. The return rate was 82.0%. In adjusted analyses, those indicating an annual income of less than $15,000 were 2.85 times more likely to return their kits (95% CI: 1.56-5.24; P < .001). Also, those not perceiving themselves to be overweight/obese were 1.95 times more likely to return their kits (95% CI: 1.07-3.55; P = .029). An outreach-based colorectal cancer screening program in a rural population may yield high return rates. People with annual incomes below $15,000 and those not having perceptions of being overweight/obese may be particularly likely to return FIT kits. © 2016 National Rural Health Association.

  20. Low-Frequency Radio Bursts and Space Weather

    Science.gov (United States)

    Gopalswamy, N.

    2016-01-01

    Low-frequency radio phenomena are due to the presence of nonthermal electrons in the interplanetary (IP) medium. Understanding these phenomena is important in characterizing the space environment near Earth and other destinations in the solar system. Substantial progress has been made in the past two decades, because of the continuous and uniform data sets available from space-based radio and white-light instrumentation. This paper highlights some recent results obtained on IP radio phenomena. In particular, the source of type IV radio bursts, the behavior of type III storms, shock propagation in the IP medium, and the solar-cycle variation of type II radio bursts are considered. All these phenomena are closely related to solar eruptions and active region evolution. The results presented were obtained by combining data from the Wind and SOHO missions.

  1. Radio-location of mobile stations in third generation networks

    Directory of Open Access Journals (Sweden)

    Milan Manojle Šunjevarić

    2013-06-01

    Full Text Available Mobile station localization in mobile networks started with simple methods (e.g. Cell-ID method which required only slight modifications of network infrastructures. Principally, it was about network localization by which a localization service became available to all types of mobile phones. Due to low precision, the initiated development of more sophisticated methods has not been finished yet. Among the advanced location-based methods are those based on the measurement of location parameters in the time domain. In this paper the general consideration of radio location methods in 3G (UMTS radio networks is presented. The use of time based measurement methods was analysed in detail. Due to the limited article length, the use of other locating methods in 3G networks (based on power measurements, on radio direction measurement, and on cells identification – Cell ID and global positioning system - GPS are not described. Introduction Mobile station localization within modern cellular networks increases the level of user security and opens wide opportunities for commercial operators who provide this service. The major obstacle for the implementation of this service, which also prevents its practical usage, is the modification of the existing network infrastructure. In general, depending on the infrastructure used, positioning methods can be divided into two groups: integrated and independent. Integrated methods are primarily created for communication networks. A possibility to locate users represents just an additional service within a radio network. Independent methods are totally detached from the communication network in which the user whose location is being determined is. Radio location methods Determining the location of a mobile radio station is performed by determining the intersection of two or more lines of position. These lines represent the position of the set of points at which the mobile station may be located. These lines can be: (a

  2. BROADBAND RADIO POLARIMETRY AND FARADAY ROTATION OF 563 EXTRAGALACTIC RADIO SOURCES

    International Nuclear Information System (INIS)

    Anderson, C. S.; Gaensler, B. M.; Feain, I. J.; Franzen, T. M. O.

    2015-01-01

    We present a broadband spectropolarimetric survey of 563 discrete, mostly unresolved radio sources between 1.3 and 2.0 GHz using data taken with the Australia Telescope Compact Array. We have used rotation-measure synthesis to identify Faraday-complex polarized sources, those objects whose frequency-dependent polarization behavior indicates the presence of material possessing complicated magnetoionic structure along the line of sight (LOS). For sources classified as Faraday-complex, we have analyzed a number of their radio and multiwavelength properties to determine whether they differ from Faraday-simple polarized sources (sources for which LOS magnetoionic structures are comparatively simple) in these properties. We use this information to constrain the physical nature of the magnetoionic structures responsible for generating the observed complexity. We detect Faraday complexity in 12% of polarized sources at ∼1′ resolution, but we demonstrate that underlying signal-to-noise limitations mean the true percentage is likely to be significantly higher in the polarized radio source population. We find that the properties of Faraday-complex objects are diverse, but that complexity is most often associated with depolarization of extended radio sources possessing a relatively steep total intensity spectrum. We find an association between Faraday complexity and LOS structure in the Galactic interstellar medium (ISM) and claim that a significant proportion of the Faraday complexity we observe may be generated at interfaces of the ISM associated with ionization fronts near neutral hydrogen structures. Galaxy cluster environments and internally generated Faraday complexity provide possible alternative explanations in some cases

  3. Extended radio sources in the cluster environment

    International Nuclear Information System (INIS)

    Burns, J.O. Jr.

    1979-01-01

    Extended radio galaxies that lie in rich and poor clusters were studied. A sample of 3CR and 4C radio sources that spatially coincide with poor Zwicky clusters of galaxies was observed to obtain accurate positions and flux densities. Then interferometer observations at a resolution of approx. = 10 arcsec were performed on the sample. The resulting maps were used to determine the nature of the extended source structure, to make secure optical identifications, and to eliminate possible background sources. The results suggest that the environments around both classical double and head-tail radio sources are similar in rich and poor clusters. The majority of the poor cluster sources exhibit some signs of morphological distortion (i.e., head-tails) indicative of dynamic interaction with a relatively dense intracluster medium. A large fraction (60 to 100%) of all radio sources appear to be members of clusters of galaxies if one includes both poor and rich cluster sources. Detailed total intensity and polarization observations for a more restricted sample of two classical double sources and nine head-tail galaxies were also performed. The purpose was to examine the spatial distributions of spectral index and polarization. Thin streams of radio emission appear to connect the nuclear radio-point components to the more extended structures in the head-tail galaxies. It is suggested that a non-relativistic plasma beam can explain both the appearance of the thin streams and larger-scale structure as well as the energy needed to generate the observed radio emission. The rich and poor radio cluster samples are combined to investigate the relationship between source morphology and the scale sizes of clustering. There is some indication that a large fraction of radio sources, including those in these samples, are in superclusters of galaxies

  4. Radio science investigations with Voyager

    International Nuclear Information System (INIS)

    Eshleman, V.R.; Tyler, G.L.; Croft, T.A.

    1977-01-01

    The planned radio science investigations during the Voyager missions to the outer planets involve: (1) the use of the radio links to and from the spacecraft for occultation measurements of planetary and satellite atmospheres and ionospheres, the rings of Saturn, the solar corona, and the general-relativistic time delay for radiowave propagation through the Sun's gravity field; (2) radio link measurements of true or apparent spacecraft motion caused by the gravity fields of the planets, the masses of their larger satellites, and characteristics of the interplanetary medium; and (3) related measurements which could provide results in other areas, including the possible detection of long-wavelength gravitational radiation propagating through the Solar System. The measurements will be used to study: atmospheric and ionospheric structure, constituents, and dynamics; the sizes, radial distribution, total mass, and other characteristics of the particles in the rings of Saturn; interior models for the major planets and the mean density and bulk composition of a number of their satellites; the plasma density and dynamics of the solar corona and interplanetary medium; and certain fundamental questions involving gravitation and relativity. The instrumentation for these experiments is the same ground-based and spacecraft radio systems as will be used for tracking and communicating with the Voyager spacecraft, although several important features of these systems have been provided primarily for the radio science investigations. (Auth.)

  5. Strategi Reputation Marketing untuk Mendapatkan Awareness Khalayak Radio (Studi Kasus: 97.5 Fm Motion Radio Jakarta

    Directory of Open Access Journals (Sweden)

    Anathasia Citra

    2013-04-01

    Full Text Available The research aims to know the implication of reputation marketing strategy in Broadcast Media Management, how the Reputation Marketing impacts the improvement of Audience awareness. This is a descriptive research using qualitative approach with the methodology of observant participatory. The result is that Reputation Marketing is essential to be conducted specially in new radio station to get attention of audiences. As the result, its increasing the awareness of the radio station and benefit for the radio station is because the increase of the numbers of advertisers.  

  6. Radio-controlled automatic gas meter-reading system; Releve automatique de compteur par radio

    Energy Technology Data Exchange (ETDEWEB)

    Yasui, M. [Osaka Gas Co., Ltd (Japan); Ishikawa, K.; Fujiwara, J. [Tokyo Gas Co., Ltd. (Japan); Ichihashi, T. [Toho Gas Co., Ltd. (Japan)

    2000-07-01

    In Japan, an automatic gas meter-reading system is in operation, also incorporating the functions of monitoring for abnormalities in gas use and remote-controlled emergency gas supply shutoff. This system has been realized by linking microcomputer-controlled gas meters(It's called 'Intelligent gas mater') equipped with automatic shutoff mechanism to the gas utility company operation center via communication lines. While the present system uses cable communication lines, we of Tokyo Gas Co., Ltd., Osaka Gas Co., Ltd. and Toho Gas Co., Ltd., have jointly developed a new system based on radio communication. This paper introduces this new system. While radio-controlled meter-reading systems are used in many countries around the world solely for automatic meter reading, our recently developed system is also capable of monitoring for abnormalities in gas use and remote-controlled emergency gas supply shutoff, thanks to its almost real-time two-way communication function. The new system can serve for a period of ten years without recharging. It is also characterized by its applicability as different systems according to purposes: 1) conventional automatic meter-reading system (terminal network control unit or T-NCU), 2) large-scale radio-controlled meter-reading system, and 3) portable terminal-type radio-controlled meter-reading system. (authors)

  7. New radio observations of NGC1275

    International Nuclear Information System (INIS)

    Pedlar, A.; Perley, R.; Crane, P.; Harrison, B.; Davies, R.D.

    1986-01-01

    VLA maps are presented for NGC1275 at 20 cm, with resolutions ranging from 1 to 40 arcsec. Over the central 30 arcsec there is evidence for collimated ejection at position angle -160 deg. Outside this region the radio structure bends rapidly by approximately 90 deg before merging into the 10-arcmin radio halo. It is suggested that models of pressure-driven accretion flows should take into account the presence of the relativistic gas which is responsible for the radio halo. 14 references

  8. Magnetar-like X-Ray Bursts Suppress Pulsar Radio Emission

    Energy Technology Data Exchange (ETDEWEB)

    Archibald, R. F.; Lyutikov, M.; Kaspi, V. M.; Tendulkar, S. P. [Department of Physics and McGill Space Institute, McGill University, 3600 University Street, Montreal, QC H3A 2T8 (Canada); Burgay, M.; Possenti, A. [INAF–Osservatorio Astronomico di Cagliari, Via della Scienza 5, I-09047 Selargius (Italy); Esposito, P.; Rea, N. [Anton Pannekoek Institute for Astronomy, University of Amsterdam, Postbus 94249, 1090 GE Amsterdam (Netherlands); Israel, G. [INAF–Osservatorio Astronomico di Roma, via Frascati 33, I-00040 Monteporzio Catone, Roma (Italy); Kerr, M. [Space Science Division, Naval Research Laboratory, Washington, DC 20375-5352 (United States); Sarkissian, J. [CSIRO Astronomy and Space Science, Parkes Observatory, P.O. Box 276, Parkes, NSW 2870 (Australia); Scholz, P., E-mail: archibald@astro.utoronto.ca [National Research Council of Canada, Herzberg Astronomy and Astrophysics, Dominion Radio Astrophysical Observatory, P.O. Box 248, Penticton, BC V2A 6J9 (Canada)

    2017-11-10

    Rotation-powered pulsars and magnetars are two different observational manifestations of neutron stars: rotation-powered pulsars are rapidly spinning objects that are mostly observed as pulsating radio sources, while magnetars, neutron stars with the highest known magnetic fields, often emit short-duration X-ray bursts. Here, we report simultaneous observations of the high-magnetic-field radio pulsar PSR J1119−6127 at X-ray, with XMM-Newton and NuSTAR , and at radio energies with the Parkes radio telescope, during a period of magnetar-like bursts. The rotationally powered radio emission shuts off coincident with the occurrence of multiple X-ray bursts and recovers on a timescale of ∼70 s. These observations of related radio and X-ray phenomena further solidify the connection between radio pulsars and magnetars and suggest that the pair plasma produced in bursts can disrupt the acceleration mechanism of radio-emitting particles.

  9. Advanced sensing techniques for cognitive radio

    CERN Document Server

    Zhao, Guodong; Li, Shaoqian

    2017-01-01

    This SpringerBrief investigates advanced sensing techniques to detect and estimate the primary receiver for cognitive radio systems. Along with a comprehensive overview of existing spectrum sensing techniques, this brief focuses on the design of new signal processing techniques, including the region-based sensing, jamming-based probing, and relay-based probing. The proposed sensing techniques aim to detect the nearby primary receiver and estimate the cross-channel gain between the cognitive transmitter and primary receiver. The performance of the proposed algorithms is evaluated by simulations in terms of several performance parameters, including detection probability, interference probability, and estimation error. The results show that the proposed sensing techniques can effectively sense the primary receiver and improve the cognitive transmission throughput. Researchers and postgraduate students in electrical engineering will find this an exceptional resource.

  10. La radio glocal cross-media: la alternativa ante la reducción de espacios de proximidad local en la radio convencional

    Directory of Open Access Journals (Sweden)

    José María Chomón Serna

    2016-01-01

    Full Text Available Palabras clave: Información, Proximidad, Radio-periódico, Inmediatez, Cross-media, Transmedia ResumenLas cadenas radiofónicas españolas, Ser, Onda Cero, Cope y RNE (Radio 5 Todo Noticias compiten por la reducción de la proximidad local, sin reparar en las consecuencias y fijando como objetivo los recortes económicos.Las cadenas radiofónicas, mediante un proceso de mimetismo, aplican una misma pauta de programación local, y tienden a instaurar un nuevo modelo radiofónico: la “radio-periódico”. Este modelo supone la pérdida de dos de las principales características de la radio: la inmediatez y la cercanía.La estrategia de reducción de contenidos locales no supone en este contexto una contradicción si se compensa mediante las herramientas que propicien que el “prosumer” acceda a contenidos “glocales”, facilitando la actividad cross-media  y el relato transmedia. Keywords: Information, Proximity, Radio-newspaper, Immediacy, Cross-media, Transmedia AbstractThe Spanish radio stations Ser, Onda Cero, Cope and RNE (Radio 5 Todo Noticias compete for the reduction of local proximity, without thinking about the consequences and setting the economic cutbacks as the only objective.The radio stations, through a mimicry process, make use of the same pattern of local schedule, having established a new radio model: the radio-newspaper. This model means the loss of two of the main radio features: The immediacy and the nearness.The reduction of local content strategy does not mean, in this context, a contradiction if it is offsetting by the tools that propitiate the access of the "prosumer" to "glocal" contents, making easier the cross-media activity and the transmedia stories.

  11. The other radios: Alternative scenario in Peru

    Directory of Open Access Journals (Sweden)

    Carlos Rivadeneyra-Olcese

    2009-10-01

    Full Text Available Peruvian radio shows a huge diversity in direct proportion to its multiculturality, the same which shows a process full of different influences of social actor which have produced a complex and extremely rich scenario, that is also filled with opportunities and challenges. Beyond the great capital commercial radio are the other radios, small companies, provincial, from church or the mayor or small business owners sons of folkloric melomania, different actors with a passion to establish a new media. The multiple motivations produce a scenario with many types of radio that we wishes to start knowing.

  12. Computing angle of arrival of radio signals

    Science.gov (United States)

    Borchardt, John J.; Steele, David K.

    2017-11-07

    Various technologies pertaining to computing angle of arrival of radio signals are described. A system that is configured for computing the angle of arrival of a radio signal includes a cylindrical sheath wrapped around a cylindrical object, where the cylindrical sheath acts as a ground plane. The system further includes a plurality of antennas that are positioned about an exterior surface of the cylindrical sheath, and receivers respectively coupled to the antennas. The receivers output measurements pertaining to the radio signal. A processing circuit receives the measurements and computes the angle of arrival of the radio signal based upon the measurements.

  13. The Dynamic Radio Sky: An Opportunity for Discovery

    Science.gov (United States)

    2010-01-01

    giant pulses from the Crab pulsar , a small number of dedicated radio transient surveys, and the serendipitous discovery of transient radio sources...used in the discovery of over 1800 radio pulsars . In 2003, the Parkes Multibeam Survey had covered the entire Galactic plane visible from Parkes... pulsars , and confirmed the neutron star nature of these sources, dubbed Rotating Radio Transients (RRATs). Since the discovery of the original 11 RRATs

  14. 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.

  15. The isotropic radio background revisited

    Energy Technology Data Exchange (ETDEWEB)

    Fornengo, Nicolao; Regis, Marco [Dipartimento di Fisica Teorica, Università di Torino, via P. Giuria 1, I–10125 Torino (Italy); Lineros, Roberto A. [Instituto de Física Corpuscular – CSIC/U. Valencia, Parc Científic, calle Catedrático José Beltrán, 2, E-46980 Paterna (Spain); Taoso, Marco, E-mail: fornengo@to.infn.it, E-mail: rlineros@ific.uv.es, E-mail: regis@to.infn.it, E-mail: taoso@cea.fr [Institut de Physique Théorique, CEA/Saclay, F-91191 Gif-sur-Yvette Cédex (France)

    2014-04-01

    We present an extensive analysis on the determination of the isotropic radio background. We consider six different radio maps, ranging from 22 MHz to 2.3 GHz and covering a large fraction of the sky. The large scale emission is modeled as a linear combination of an isotropic component plus the Galactic synchrotron radiation and thermal bremsstrahlung. Point-like and extended sources are either masked or accounted for by means of a template. We find a robust estimate of the isotropic radio background, with limited scatter among different Galactic models. The level of the isotropic background lies significantly above the contribution obtained by integrating the number counts of observed extragalactic sources. Since the isotropic component dominates at high latitudes, thus making the profile of the total emission flat, a Galactic origin for such excess appears unlikely. We conclude that, unless a systematic offset is present in the maps, and provided that our current understanding of the Galactic synchrotron emission is reasonable, extragalactic sources well below the current experimental threshold seem to account for the majority of the brightness of the extragalactic radio sky.

  16. The isotropic radio background revisited

    International Nuclear Information System (INIS)

    Fornengo, Nicolao; Regis, Marco; Lineros, Roberto A.; Taoso, Marco

    2014-01-01

    We present an extensive analysis on the determination of the isotropic radio background. We consider six different radio maps, ranging from 22 MHz to 2.3 GHz and covering a large fraction of the sky. The large scale emission is modeled as a linear combination of an isotropic component plus the Galactic synchrotron radiation and thermal bremsstrahlung. Point-like and extended sources are either masked or accounted for by means of a template. We find a robust estimate of the isotropic radio background, with limited scatter among different Galactic models. The level of the isotropic background lies significantly above the contribution obtained by integrating the number counts of observed extragalactic sources. Since the isotropic component dominates at high latitudes, thus making the profile of the total emission flat, a Galactic origin for such excess appears unlikely. We conclude that, unless a systematic offset is present in the maps, and provided that our current understanding of the Galactic synchrotron emission is reasonable, extragalactic sources well below the current experimental threshold seem to account for the majority of the brightness of the extragalactic radio sky

  17. Energy-Aware Cognitive Radio Systems

    KAUST Repository

    Bedeer, Ebrahim

    2016-01-15

    The concept of energy-aware communications has spurred the interest of the research community in the most recent years due to various environmental and economical reasons. It becomes indispensable for wireless communication systems to shift their resource allocation problems from optimizing traditional metrics, such as throughput and latency, to an environmental-friendly energy metric. Although cognitive radio systems introduce spectrum efficient usage techniques, they employ new complex technologies for spectrum sensing and sharing that consume extra energy to compensate for overhead and feedback costs. Considering an adequate energy efficiency metric—that takes into account the transmit power consumption, circuitry power, and signaling overhead—is of momentous importance such that optimal resource allocations in cognitive radio systems reduce the energy consumption. A literature survey of recent energy-efficient based resource allocations schemes is presented for cognitive radio systems. The energy efficiency performances of these schemes are analyzed and evaluated under power budget, co-channel and adjacent-channel interferences, channel estimation errors, quality-of-service, and/or fairness constraints. Finally, the opportunities and challenges of energy-aware design for cognitive radio systems are discussed.

  18. Interference-aware power control for multi-radio multi-channel wireless mesh networks

    CSIR Research Space (South Africa)

    Olwal, TO

    2009-09-01

    Full Text Available are well known in [9], [6]. The operation of multi-radio multi-channel (MRMC) WMNs generally requires sustainable energy supply. Substantial deployments of WMNs have recently been witnessed in rural and remote communities [4]. In such applications...]. Power resources are dynamically adjusted by each NIC using intra and inter-subsystem (channel) states. Due to the decentralized nature, each MP assumes imperfect knowledge about the global network. Further we assume that there exists...

  19. Reducing Disparity in Radio-Isotopic and Astrochronology-Based Time Scales of the Late Eocene and Oligocene

    NARCIS (Netherlands)

    Sahy, Diana; Condon, Daniel J.; Hilgen, Frederik J.|info:eu-repo/dai/nl/102639876; Kuiper, Klaudia F.|info:eu-repo/dai/nl/258125772

    2017-01-01

    A significant discrepancy of up to 0.6 Myr exists between radio-isotopically calibrated and astronomically tuned time scales of the late Eocene-Oligocene. We explore the possible causes of this discrepancy through the acquisition of “high-precision” 206Pb/238U dating of zircons from 11 volcanic ash

  20. College radio as a mechanism for participatory learning: Exploring the scope for online radio based learning among undergraduates

    Directory of Open Access Journals (Sweden)

    Bahaeldin Ibrahim

    2016-03-01

    Full Text Available This paper explores the prospects of online college radio at Sur College of Applied Sciences, its need among students and the possible scope of its contributions to student learning, engagement and community service. It explores the method of developing a holistic mechanism to capture the possibilities of maximizing learning experience by employing college radio as an educational tool to understand the micro-dynamics and localized necessities that deem it necessary or unnecessary. Through this, it attempts to locate an appropriate mechanism, and targeted use of the college radio in contributing to the learning outcomes and educational experience of the students. The study finds considerable scope for radio based learning at Sur College of Applied Sciences across a range of uses and gratification indicators consistent with the primary objectives of the college. The study discusses the theoretical and practical implications of the findings, and the pedagogical significance of the college radio as an alternative.

  1. Radio communication in mines: information, data processing (Report on ECSC contract 7220-AF/201)

    Energy Technology Data Exchange (ETDEWEB)

    Delogne, P; de Keyser, R; Deryck, L; Fourny, R; Hellin, H; Leonard, D [INIEX

    1980-01-01

    The aim of the research was to develop and construct transmitter-receivers for use in coal mines for communication transmission of signals and remote control. The reliability, miniaturization and ease of handling of existing equipment were improved. Research was carried out into interfaces between traditional remote-sensing elements and a radio transmission line. The intelligibility of spoken messages was also investigated. (In French)

  2. 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.

  3. Plasma Diagnostics of the Interstellar Medium with Radio Astronomy

    OpenAIRE

    Haverkorn, Marijke; Spangler, Steven R.

    2013-01-01

    We discuss the degree to which radio propagation measurements diagnose conditions in the ionized gas of the interstellar medium (ISM). The "signal generators" of the radio waves of interest are extragalactic radio sources (quasars and radio galaxies), as well as Galactic sources, primarily pulsars. The polarized synchrotron radiation of the Galactic non-thermal radiation also serves to probe the ISM, including space between the emitting regions and the solar system. Radio propagation measurem...

  4. La radio no está amenazada por internet

    Directory of Open Access Journals (Sweden)

    Bruce Girard

    2015-01-01

    Full Text Available La radio es mucho más penetrante y asequible, el uso de los servicios de Internet puede contribuir a informar mejor a sus clientes y establecer interactividad. En vista que por ahora la accesibilidad del Internet es accesible solo a unos pocos, para la radio no es una amenaza el Internet. Enuncia los roles de la radio y señala que está considerada como un vínculo comunitario. Trata además sobre las radio-cadenas satelitales, la radio e Internet: convergencia para la democracia y el crecimiento de la brecha de los que acceden a la información.

  5. An Optical Receiver Post Processing System for the Integrated Radio and Optical Communications Software Defined Radio Test Bed

    Science.gov (United States)

    Nappier, Jennifer M.; Tokars, Roger P.; Wroblewski, Adam C.

    2016-01-01

    The Integrated Radio and Optical Communications (iROC) project at the National Aeronautics and Space Administrations (NASA) Glenn Research Center is investigating the feasibility of a hybrid radio frequency (RF) and optical communication system for future deep space missions. As a part of this investigation, a test bed for a radio frequency (RF) and optical software defined radio (SDR) has been built. Receivers and modems for the NASA deep space optical waveform are not commercially available so a custom ground optical receiver system has been built. This paper documents the ground optical receiver, which is used in order to test the RF and optical SDR in a free space optical communications link.

  6. An Optical Receiver Post-Processing System for the Integrated Radio and Optical Communications Software Defined Radio Test Bed

    Science.gov (United States)

    Nappier, Jennifer M.; Tokars, Roger P.; Wroblewski, Adam C.

    2016-01-01

    The Integrated Radio and Optical Communications (iROC) project at the National Aeronautics and Space Administration's (NASA) Glenn Research Center is investigating the feasibility of a hybrid radio frequency (RF) and optical communication system for future deep space missions. As a part of this investigation, a test bed for a radio frequency (RF) and optical software defined radio (SDR) has been built. Receivers and modems for the NASA deep space optical waveform are not commercially available so a custom ground optical receiver system has been built. This paper documents the ground optical receiver, which is used in order to test the RF and optical SDR in a free space optical communications link.

  7. Contribution Towards Practical Cognitive Radios Systems

    KAUST Repository

    Ben Ghorbel, Mahdi

    2013-01-01

    to cognitive radio systems while taking into account practical constraints. Cogni- tive radios requires a capability to detect spectrum holes (spectrum sensing) and a scheduling flexibility to avoid the occupied spectrum and selectively use the empty spectrum

  8. NASH BARGAINING BASED BANDWIDTH ALLOCATION IN COGNITIVE RADIO FOR DELAY CRITICAL APPLICATIONS

    Directory of Open Access Journals (Sweden)

    Kalyani Kulkarni

    2015-11-01

    Full Text Available In order to effectively regulate the existing resources, dynamic spectrum access in cognitive radio needs to adopt the effective resource allocation strategies. Multimedia applications require large bandwidth and have to meet the delay constraints while maintaining the data quality. Game theory is emerging as an effective analytical tool for the analysis of available resources and its allocation. This paper addresses resource allocation schemes employing bargaining game model for Multi-carrier CDMA based Cognitive Radio. Resource allocation scheme is designed for transmission of video over cognitive radio networks and aim to perform bandwidth allocation for different cognitive users. Utility function based on bargaining model is proposed. Primary user utility function includes the pricing factor and an upbeat factor that can be adjusted by observing the delay constraints of the video. Allocated bandwidth to the secondary user can be adjusted by changing the upbeat factor. Throughput in the proposed scheme is increased by 2% as compared to other reported pricing based resource allocation schemes. The edge PSNR of reconstructed video obtained as 32.6dB resulting to optimum decoding of the video at the receiver. The study also shows upbeat factor can be used to enhanced capacity of the network.

  9. Solar cooker effect test and temperature field simulation of radio telescope subreflector

    International Nuclear Information System (INIS)

    Chen, Deshen; Wang, Huajie; Qian, Hongliang; Zhang, Gang; Shen, Shizhao

    2016-01-01

    Highlights: • Solar cooker effect test of a telescope subreflector is conducted for the first time. • The cause and temperature distribution regularities are analyzed contrastively. • Simulation methods are proposed using light beam segmentation and tracking methods. • The validity of simulation methods is evaluated using the test results. - Abstract: The solar cooker effect can cause a local high temperature of the subreflector and can directly affect the working performance of the radio telescope. To study the daily temperature field and solar cooker effect of a subreflector, experimental studies are carried out with a 3-m-diameter radio telescope model for the first time. Initially, the solar temperature distribution rules, especially the solar cooker effect, are summarized according to the field test results under the most unfavorable conditions. Then, a numerical simulation for the solar temperature field of the subreflector is studied by light beam segmentation and tracking methods. Finally, the validity of the simulation methods is evaluated using the test results. The experimental studies prove that the solar cooker effect really exists and should not be overlooked. In addition, simulation methods for the subreflector temperature field proposed in this paper are effective. The research methods and conclusions can provide valuable references for thermal design, monitoring and control of similar high-precision radio telescopes.

  10. 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.

  11. 77 FR 61535 - Private Land Mobile Radio Rules

    Science.gov (United States)

    2012-10-10

    ... technology that we believe can provide valuable benefits to land mobile radio users. III. Summary of..., GPS equipment, pagers, cellular phones, mobile communications equipment, and radio and television...-114] Private Land Mobile Radio Rules AGENCY: Federal Communications Commission. ACTION: Final rule...

  12. VHF spectrum monitoring using Meraka cognitive radio platform

    CSIR Research Space (South Africa)

    Aderonmu, AI

    2012-11-01

    Full Text Available discuss the Meraka Cognitive Radio Platform (MCRP) developed using the second version of the Universal Serial Radio Peripheral (USRP2) hardware and the GNU Radio software. We also discussed how the spectrum monitoring system is being implemented...

  13. 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...

  14. Observations of neutral hydrogen in radio-loud and interacting galaxies

    Science.gov (United States)

    Heckman, T. M.; Balick, B.; Van Breugel, W. J. W.; Miley, G. K.

    1983-01-01

    The results of a survey of H I in radio-loud and interacting galaxies is presented. Four cases of H I absorption and five of emission are reported. The interesting features found for individual galaxies are described, and the systematic properties are discussed. Column densities of absorbing gas generally exceed those expected for a 'Milky Way' H I disk by more than an order of magnitude. The absorbing gas must have a flattened, disklike morphology oriented roughly parallel to the optical disk of the galaxy. Turbulent noncircular gas motions are evidently present, which are shown to be almost certainly induced by galaxy-galaxy interactions. The set of galaxies in which H I absorption has been detected is dominated by morphologically peculiar objects. It is concluded that the detection of H I seen in absorption against a nuclear radio source permits direct determination of the sense of radial flow of extranuclear material, and is direct evidence that potential 'food' for a compact object in the nucleus exists in the galaxy.

  15. The statistics of low frequency radio interference at the Murchison Radio-astronomy Observatory

    OpenAIRE

    Sokolowski, Marcin; Wayth, Randall B.; Lewis, Morgan

    2016-01-01

    We characterize the low frequency radio-frequency interference (RFI) environment at the Murchison Radio-astronomy Observatory (MRO), the location selected for the low-frequency component of the Square Kilometre Array. Data were collected from the BIGHORNS instrument, located at the MRO, which records a contiguous bandwidth between 70 and 300 MHz, between November 2014 to March 2015 inclusive. The data were processed to identify RFI, and we describe a series of statistics in both the time and ...

  16. Radio transmission system for industrial area

    International Nuclear Information System (INIS)

    Iliescu, M.; Culcer, M.; Curuia, M.; Anghel, N.M.; Stefanescu, I.

    2003-01-01

    The paper deals with a data transmission system operating in a large, noisy industrial area. The radio transmission system permits data and commands communication between the local units of collecting data and a central monitoring and/or command station ( dispatch). The communication support are radio waves in the range 450 MHz. The transducers are of transmitter type, with 4-20 mA output signal, providing information about environmental and/or work parameters. Data are primarily acquisitioned in a data logger with microcontroller, then transmitted via a FSK radio modem and a radio station to the dispatch. Data logger can also be connected in a network. The dispatch personal computer receives and processes data and transmits commands. The system functioning is supervised by a communication software in MCS - 51 assembler and an application software in Visual C ++ . (author)

  17. Radio-continuum emission from quasar host galaxies

    International Nuclear Information System (INIS)

    Condon, J. J.; Gower, A. C.; Hutchings, J. B.; Victoria Univ., Canada; Dominion Astrophysical Observatory, Victoria)

    1987-01-01

    Seven low-redshift quasars that are likely to be in spiral galaxies have been observed in a search for radio-continuum emission from the host galaxies of quasars. The properties of the individual quasars are listed, and 1.49 GHz contour maps of the seven quasar fields are presented. Map parameters and radio source parameters are given along with optical images of three of the objects. The results indicate that these quasars probably do reside in spiral galaxies. The radio luminosities, sizes, orientations, and u values all indicate that relativistic beaming alone cannot be used to explain the differences between the present sources and the far stronger radio sources seen in blazars or larger optically selected quasar samples. However, an apparent correlation between the radio luminosity and the ratio of the optical nuclear to host-galaxy luminosity is consistent with some beaming of nuclear radiation. 26 references

  18. Optical spectra and radio properties of quasars

    International Nuclear Information System (INIS)

    Wills, B.J.

    1982-01-01

    Using high quality spectrophotometric scans obtained at the McDonald Observatory, and data from the literature the author shows that, for quasars, the relative strength of optical Fe II emission (the broad blended feature lambda4570) may be roughly inversely proportional to line widths (full width at half maximum, FWHM). A similar relation between the relative intensity of the UV Fe II blend between 2300 and 2600 A (the lambda2500 feature) and the widths of Mg II and Hβ is shown. She distinguishes between compact and extended radio sources and includes radio quiet quasars, Seyfert 1 galaxies and BLRG's. The quasars associated with extended radio sources have the broadest emission lines and the weakest Fe II, falling close to the region occupied by BLRG's which also have extended radio structure. Those quasars with strong Fe II and compact radio structure are most similar to the Seyfert 1 galaxies. (Auth.)

  19. Hybrid cognitive engine for radio systems adaptation

    KAUST Repository

    Alqerm, Ismail

    2017-07-20

    Network efficiency and proper utilization of its resources are essential requirements to operate wireless networks in an optimal fashion. Cognitive radio aims to fulfill these requirements by exploiting artificial intelligence techniques to create an entity called cognitive engine. Cognitive engine exploits awareness about the surrounding radio environment to optimize the use of radio resources and adapt relevant transmission parameters. In this paper, we propose a hybrid cognitive engine that employs Case Based Reasoning (CBR) and Decision Trees (DTs) to perform radio adaptation in multi-carriers wireless networks. The engine complexity is reduced by employing DTs to improve the indexing methodology used in CBR cases retrieval. The performance of our hybrid engine is validated using software defined radios implementation and simulation in multi-carrier environment. The system throughput, signal to noise and interference ratio, and packet error rate are obtained and compared with other schemes in different scenarios.

  20. Real-Time Measurements for Adaptive and Cognitive Radio Systems

    Directory of Open Access Journals (Sweden)

    Hüseyin Arslan

    2009-01-01

    Full Text Available Adaptive and cognitive radios (CR have been becoming popular for optimizing mobile radio system transmission and reception. One of the most important elements of the adaptive radio and CR concepts is the ability to measure, sense, learn about, and be aware of parameters related to the radio channel characteristics, availability of spectrum and power, interference and noise temperature, operational environment of radio, user requirements and applications, available networks and infrastructures, local policies, other operating restrictions, and so on. This paper discusses some of the important measurement parameters for enabling adaptive radio and CR systems along with their relationships and impacts on the performance including relevant challenges.

  1. Optical identifications of flat-spectrum radio sources

    International Nuclear Information System (INIS)

    Condon, J.J.; Condon, M.A.; Broderick, J.J.; Davis, M.M.

    1983-01-01

    A complete sample of radio sources with S> or =0.3 Jy at 1400 MHz, +24 0 0 , and low-frequency spectral indices α(408, 1400) or =+0.5 are usually in empty fields. The lower limits that can be assigned to the radio-optical spectral indices α/sub RO/ of these sources are significantly higher than the median α/sub RO/ of the sources with flat high-frequency spectra, so the optical characteristics of the two classes of radio source are intrinsically different. The radio and optical fluxes of flat-spectrum QSO's appear to be correlated, at least when averaged over 10 2 --10 3 yr

  2. Emergence of radio astronomy-the Indian scenario

    International Nuclear Information System (INIS)

    Das Gupta, M.K.

    1990-01-01

    Professor S.K. Mitra, the initiator of post graduate studies in radio-electronics and the pioneer of radio research in India realized the far-reaching importance of the then emerging science of radio astronomy, as early as mid-forties. The exposition of the subject has been dedicated to the memory of esteemed Professor S.K. Mitra. The article is divided into three broad heads, namely (i)the emergence of radioastronomy-achievements made so far, (ii)some major contributions made by the Indian scientists working abroad in the fifties, and (iii) the emergence of radio astronomy in India and its present status. (author). 55 refs

  3. Cognitive Radio MAC Protocol for WLAN

    DEFF Research Database (Denmark)

    Zhang, Qi; Fitzek, Frank H.P.; Iversen, Villy Bæk

    2008-01-01

    hole; moreover, it designs dual inband sensing scheme to detect primary user appearance. Additionally, C-CSMA/CA has the advantage to effectively solve the cognitive radio self-coexistence issues in the overlapping CR BSSs scenario. It also realizes station-based dynamic resource selection......To solve the performance degradation issue in current WLAN caused by the crowded unlicensed spectrum, we propose a cognitive radio (CR) media access protocol, C-CSMA/CA. The basic idea is that with cognitive radio techniques the WLAN devices can not only access the legacy WLAN unlicensed spectrum...

  4. Predicting radio fluxes of extrasolar planets (Griessmeier+, 2007)

    NARCIS (Netherlands)

    Griessmeier, J.M.; Zarka, P.; Spreeuw, H.

    2007-01-01

    Expected radio emission from presently known exoplanets. For each of the currently known exoplanets, we list its estimated magnetic moment, maximum radio emission frequency, plasma frequency in the ambient stellar wind, and radio fluxes according to three different models. (1 data file).

  5. 47 CFR 0.485 - Commercial radio operator examinations.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Commercial radio operator examinations. 0.485....485 Commercial radio operator examinations. Generally, written and telegraphy examinations for commercial radio operator licenses shall be conducted at locations and times specified by commercial operator...

  6. Radio imaging of core-dominated high redshift quasars

    DEFF Research Database (Denmark)

    Barthel, Peter D.; Vestergaard, Marianne; Lonsdale, Colin J.

    1999-01-01

    VLA imaging at kiloparsec-scale resolution of sixteen core-dominated radio-loud QSOs is presented. Many objects appear to display variable radio emission and their radio morphologies are significantly smaller than those of steep-spectrum quasars, consistent with these objects being observed...

  7. Flattening and radio emission among elliptical galaxies

    International Nuclear Information System (INIS)

    Disney, M.J.; Sparks, W.B.; Wall, J.V.

    1984-01-01

    In a sample of 132 bright elliptical galaxies it is shown that there is a strong correlation between radio activity and flattening in the sense that radio ellipticals are both apparently and inherently rounder than the average elliptical. Both extended and compact sources are subject to the same correlation. No galaxies with axial ratios below 0.65 are found to be radio emitters. (author)

  8. Impact on colorectal cancer mortality of screening programmes based on the faecal immunochemical test.

    Science.gov (United States)

    Zorzi, Manuel; Fedeli, Ugo; Schievano, Elena; Bovo, Emanuela; Guzzinati, Stefano; Baracco, Susanna; Fedato, Chiara; Saugo, Mario; Dei Tos, Angelo Paolo

    2015-05-01

    Colorectal cancer (CRC) screening programmes based on the guaiac faecal occult blood test (gFOBT) reduce CRC-specific mortality. Several studies have shown higher sensitivity with the faecal immunochemical test (FIT) compared with gFOBT. We carried out an ecological study to evaluate the impact of FIT-based screening programmes on CRC mortality. In the Veneto Region (Italy), biennial FIT-based screening programmes that invited 50-69-year-old residents were introduced in different areas between 2002 and 2009. We compared CRC mortality rates from 1995 to 2011 between the areas where screening started in 2002-2004 (early screening areas (ESA)) and areas that introduced the screening in 2008-2009 (late screening areas (LSA)) using Poisson regression models. We also compared available data on CRC incidence rates (1995-2007) and surgical resection rates (2001-2012). Before the introduction of screening, CRC mortality and incidence rates in the two areas were similar. Compared with 1995-2000, 2006-2011 mortality rates were 22% lower in the ESA than in the LSA (rate ratio (RR)=0.78; 95% CI 0.68 to 0.89). The reduction was larger in women (RR=0.64; CI 0.51 to 0.80) than in men (RR=0.87; CI 0.73 to 1.04). In the ESA, incidence and surgery rates peaked during the introduction of the screening programme and then returned to the baseline (2006-2007 incidence) or dropped below initial values (surgery after 2007). FIT-based screening programmes were associated with a significant reduction in CRC mortality. This effect took place much earlier than reported by gFOBT-based trials and observational studies. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  9. radio frequency based radio frequency based water level monitor

    African Journals Online (AJOL)

    eobe

    ABSTRACT. This paper elucidates a radio frequency (RF) based transmission and reception system used to remotely monitor and .... range the wireless can cover but in this prototype, it ... power supply to the system, the sensed water level is.

  10. X-ray Counterparts of Infrared Faint Radio Sources

    Science.gov (United States)

    Schartel, Norbert

    2011-10-01

    Infrared Faint Radio Sources (IFRS) are radio sources with extremely faint or even absent infrared emission in deep Spitzer Surveys. Models of their spectral energy distributions, the ratios of radio to infrared flux densities and their steep radio spectra strongly suggest that IFRS are AGN at high redshifts (2IFRS, but if confirmed, the increased AGN numbers at these redshifts will account for the unresolved part of the X-ray background. The identification of X-ray counterparts of IFRS is considered to be the smoking gun for this hypothesis. We propose to observe 8 IFRS using 30ks pointed observations. X-ray detections of IFRS with different ratios of radio-to-infrared fluxes, will constrain the class-specific SED.

  11. 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.

  12. Wavelet Denoising of Radio Observations of Rotating Radio Transients (RRATs): Improved Timing Parameters for Eight RRATs

    Science.gov (United States)

    Jiang, M.; Cui, B.-Y.; Schmid, N. A.; McLaughlin, M. A.; Cao, Z.-C.

    2017-09-01

    Rotating radio transients (RRATs) are sporadically emitting pulsars detectable only through searches for single pulses. While over 100 RRATs have been detected, only a small fraction (roughly 20%) have phase-connected timing solutions, which are critical for determining how they relate to other neutron star populations. Detecting more pulses in order to achieve solutions is key to understanding their physical nature. Astronomical signals collected by radio telescopes contain noise from many sources, making the detection of weak pulses difficult. Applying a denoising method to raw time series prior to performing a single-pulse search typically leads to a more accurate estimation of their times of arrival (TOAs). Taking into account some features of RRAT pulses and noise, we present a denoising method based on wavelet data analysis, an image-processing technique. Assuming that the spin period of an RRAT is known, we estimate the frequency spectrum components contributing to the composition of RRAT pulses. This allows us to suppress the noise, which contributes to other frequencies. We apply the wavelet denoising method including selective wavelet reconstruction and wavelet shrinkage to the de-dispersed time series of eight RRATs with existing timing solutions. The signal-to-noise ratio (S/N) of most pulses are improved after wavelet denoising. Compared to the conventional approach, we measure 12%–69% more TOAs for the eight RRATs. The new timing solutions for the eight RRATs show 16%–90% smaller estimation error of most parameters. Thus, we conclude that wavelet analysis is an effective tool for denoising RRATs signal.

  13. Wavelet Denoising of Radio Observations of Rotating Radio Transients (RRATs): Improved Timing Parameters for Eight RRATs

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, M.; Schmid, N. A.; Cao, Z.-C. [Lane Department of Computer Science and Electrical Engineering West Virginia University Morgantown, WV 26506 (United States); Cui, B.-Y.; McLaughlin, M. A. [Department of Physics and Astronomy West Virginia University Morgantown, WV 26506 (United States)

    2017-09-20

    Rotating radio transients (RRATs) are sporadically emitting pulsars detectable only through searches for single pulses. While over 100 RRATs have been detected, only a small fraction (roughly 20%) have phase-connected timing solutions, which are critical for determining how they relate to other neutron star populations. Detecting more pulses in order to achieve solutions is key to understanding their physical nature. Astronomical signals collected by radio telescopes contain noise from many sources, making the detection of weak pulses difficult. Applying a denoising method to raw time series prior to performing a single-pulse search typically leads to a more accurate estimation of their times of arrival (TOAs). Taking into account some features of RRAT pulses and noise, we present a denoising method based on wavelet data analysis, an image-processing technique. Assuming that the spin period of an RRAT is known, we estimate the frequency spectrum components contributing to the composition of RRAT pulses. This allows us to suppress the noise, which contributes to other frequencies. We apply the wavelet denoising method including selective wavelet reconstruction and wavelet shrinkage to the de-dispersed time series of eight RRATs with existing timing solutions. The signal-to-noise ratio (S/N) of most pulses are improved after wavelet denoising. Compared to the conventional approach, we measure 12%–69% more TOAs for the eight RRATs. The new timing solutions for the eight RRATs show 16%–90% smaller estimation error of most parameters. Thus, we conclude that wavelet analysis is an effective tool for denoising RRATs signal.

  14. Modeling Phase-Aligned Gamma-Ray and Radio Millisecond Pulsar Light Curves

    Science.gov (United States)

    Venter, C.; Johnson, T.; Harding, A.

    2012-01-01

    Since the discovery of the first eight gamma-ray millisecond pulsars (MSPs) by the Fermi Large Area Telescope, this population has been steadily expanding. Four of the more recent detections, PSR J00340534, PSR J1939+2134 (B1937+21; the first MSP ever discovered), PSR J1959+2048 (B1957+20; the first discovery of a black widow system), and PSR J2214+3000, exhibit a phenomenon not present in the original discoveries: nearly phase-aligned radio and gamma-ray light curves (LCs). To account for the phase alignment, we explore models where both the radio and gamma-ray emission originate either in the outer magnetosphere near the light cylinder or near the polar caps. Using a Markov Chain Monte Carlo technique to search for best-fit model parameters, we obtain reasonable LC fits for the first three of these MSPs in the context of altitude-limited outer gap (alOG) and two-pole caustic (alTPC) geometries (for both gamma-ray and radio emission). These models differ from the standard outer gap (OG)/two-pole caustic (TPC) models in two respects: the radio emission originates in caustics at relatively high altitudes compared to the usual conal radio beams, and we allow both the minimum and maximum altitudes of the gamma-ray and radio emission regions to vary within a limited range (excluding the minimum gamma-ray altitude of the alTPC model, which is kept constant at the stellar radius, and that of the alOG model, which is set to the position-dependent null charge surface altitude). Alternatively, phase-aligned solutions also exist for emission originating near the stellar surface in a slot gap scenario (low-altitude slot gap (laSG) models). We find that the alTPC models provide slightly better LC fits than the alOG models, and both of these give better fits than the laSG models (for the limited range of parameters considered in the case of the laSG models). Thus, our fits imply that the phase-aligned LCs are likely of caustic origin, produced in the outer magnetosphere, and

  15. Intranuclear biophotonics by smart design of nuclear-targeting photo-/radio-sensitizers co-loaded upconversion nanoparticles.

    Science.gov (United States)

    Fan, Wenpei; Shen, Bo; Bu, Wenbo; Zheng, Xiangpeng; He, Qianjun; Cui, Zhaowen; Ni, Dalong; Zhao, Kuaile; Zhang, Shengjian; Shi, Jianlin

    2015-11-01

    Biophotonic technology that uses light and ionizing radiation for positioned cancer therapy is a holy grail in the field of biomedicine because it can overcome the systemic toxicity and adverse side effects of conventional chemotherapy. However, the existing biophotonic techniques fail to achieve the satisfactory treatment efficacy, which remains a big challenge for clinical implementation. Herein, we develop a novel theranostic technique of "intranuclear biophotonics" by the smart design of a nuclear-targeting biophotonic system based on photo-/radio-sensitizers covalently co-loaded upconversion nanoparticles. These nuclear-targeting biophotonic agents can not only generate a great deal of multiple cytotoxic reactive oxygen species in the nucleus by making full use of NIR/X-ray irradiation, but also produce greatly enhanced intranuclear synergetic radio-/photodynamic therapeutic effects under the magnetic/luminescent bimodal imaging guidance, which may achieve the optimal efficacy in treating radio-resistant tumors. We anticipate that the highly effective intranuclear biophotonics will contribute significantly to the development of biophotonic techniques and open new perspectives for a variety of cancer theranostic applications. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. BioRadioTransmitter: a self-powered wireless glucose-sensing system.

    Science.gov (United States)

    Hanashi, Takuya; Yamazaki, Tomohiko; Tsugawa, Wakako; Ikebukuro, Kazunori; Sode, Koji

    2011-09-01

    Although an enzyme fuel cell can be utilized as a glucose sensor, the output power generated is too low to power a device such as a currently available transmitter and operating system, and an external power source is required for operating an enzyme-fuel-cell-based biosensing system. We proposed a novel biosensor that we named BioCapacitor, in which a capacitor serves as a transducer. In this study, we constructed a new BioCapacitor-based system with an added radio-transmitter circuit and a miniaturized enzyme fuel cell. A miniaturized direct-electron-transfer-type compartmentless enzyme fuel cell was constructed with flavin adenine dinucleotide-dependent glucose dehydrogenase complex-based anode and a bilirubin-oxidase-based cathode. For construction of a BioRadioTransmitter wireless sensing system, a capacitor, an ultra-low-voltage charge-pump-integrated circuit, and Hartley oscillator circuit were connected to the miniaturized enzyme fuel cell. A radio-receiver circuit, comprising two field-effect transistors and a coil as an antenna, was used to amplify the signal generated from the biofuel cells. Radio wave signals generated by the BioRadioTransmitter were received, amplified, and converted from alternate to direct current by the radio receiver. When the capacitor discharges in the presence of glucose, the BioRadioTransmitter generates a radio wave, which is monitored by a radio receiver connected wirelessly to the sensing device. Magnitude of the radio wave transmission frequency change observed at the radio receiver was correlated to glucose concentration in the fuel cells. We constructed a stand-alone, self-powered, wireless glucose-sensing system called a BioRadioTransmitter by using a radio transmitter in which the radio wave transmission frequency changes with the glucose concentration in the fuel cell. The BioRadioTransmitter is a significant advance toward construction of an implantable continuous glucose monitor. © 2011 Diabetes Technology Society.

  17. Extended Radio Emission in MOJAVE Blazars: Challenges to Unification

    Science.gov (United States)

    Kharb, P.; Lister, M. L.; Cooper, N. J.

    2010-02-01

    We present the results of a study on the kiloparsec-scale radio emission in the complete flux density limited MOJAVE sample, comprising 135 radio-loud active galactic nuclei. New 1.4 GHz Very Large Array (VLA) radio images of six quasars and previously unpublished images of 21 blazars are presented, along with an analysis of the high-resolution (VLA A-array) 1.4 GHz emission for the entire sample. While extended emission is detected in the majority of the sources, about 7% of the sources exhibit only radio core emission. We expect more sensitive radio observations, however, to detect faint emission in these sources, as we have detected in the erstwhile "core-only" source, 1548+056. The kiloparsec-scale radio morphology varies widely across the sample. Many BL Lac objects exhibit extended radio power and kiloparsec-scale morphology typical of powerful FRII jets, while a substantial number of quasars possess radio powers intermediate between FRIs and FRIIs. This poses challenges to the simple radio-loud unified scheme, which links BL Lac objects to FRIs and quasars to FRIIs. We find a significant correlation between extended radio emission and parsec-scale jet speeds: the more radio powerful sources possess faster jets. This indicates that the 1.4 GHz (or low-frequency) radio emission is indeed related to jet kinetic power. Various properties such as extended radio power and apparent parsec-scale jet speeds vary smoothly between different blazar subclasses, suggesting that, at least in terms of radio jet properties, the distinction between quasars and BL Lac objects, at an emission-line equivalent width of 5 Å, is essentially an arbitrary one. While the two blazar subclasses display a smooth continuation in properties, they often reveal differences in the correlation test results when considered separately. This can be understood if, unlike quasars, BL Lac objects do not constitute a homogeneous population, but rather include both FRI and FRII radio galaxies for

  18. EXTENDED RADIO EMISSION IN MOJAVE BLAZARS: CHALLENGES TO UNIFICATION

    International Nuclear Information System (INIS)

    Kharb, P.; Lister, M. L.; Cooper, N. J.

    2010-01-01

    We present the results of a study on the kiloparsec-scale radio emission in the complete flux density limited MOJAVE sample, comprising 135 radio-loud active galactic nuclei. New 1.4 GHz Very Large Array (VLA) radio images of six quasars and previously unpublished images of 21 blazars are presented, along with an analysis of the high-resolution (VLA A-array) 1.4 GHz emission for the entire sample. While extended emission is detected in the majority of the sources, about 7% of the sources exhibit only radio core emission. We expect more sensitive radio observations, however, to detect faint emission in these sources, as we have detected in the erstwhile 'core-only' source, 1548+056. The kiloparsec-scale radio morphology varies widely across the sample. Many BL Lac objects exhibit extended radio power and kiloparsec-scale morphology typical of powerful FRII jets, while a substantial number of quasars possess radio powers intermediate between FRIs and FRIIs. This poses challenges to the simple radio-loud unified scheme, which links BL Lac objects to FRIs and quasars to FRIIs. We find a significant correlation between extended radio emission and parsec-scale jet speeds: the more radio powerful sources possess faster jets. This indicates that the 1.4 GHz (or low-frequency) radio emission is indeed related to jet kinetic power. Various properties such as extended radio power and apparent parsec-scale jet speeds vary smoothly between different blazar subclasses, suggesting that, at least in terms of radio jet properties, the distinction between quasars and BL Lac objects, at an emission-line equivalent width of 5 A, is essentially an arbitrary one. While the two blazar subclasses display a smooth continuation in properties, they often reveal differences in the correlation test results when considered separately. This can be understood if, unlike quasars, BL Lac objects do not constitute a homogeneous population, but rather include both FRI and FRII radio galaxies for

  19. La Radio Comunitaria ¿Cómo resignificarla hoy?

    OpenAIRE

    Gretta Paiz Malespín

    2016-01-01

    Las Radios Comunitarias surgieron en América Latina, como medios alternativos a la radio comercial y la radio estatal. Se posicionaron como una herramienta indispensable en el debate de temas emergentes desde la comunidad en un contexto marcado por principios de unidad, consenso, participación, discernimiento y diálogo. No obstante, hoy esos contextos han cambiado, por lo que se hace inevitable abrir el debate y discutir las condiciones actuales de las Radios Comunitarias, bajo la premisa de ...

  20. Associating Fast Radio Bursts with Extragalactic Radio Sources: General Methodology and a Search for a Counterpart to FRB 170107

    Science.gov (United States)

    Eftekhari, T.; Berger, E.; Williams, P. K. G.; Blanchard, P. K.

    2018-06-01

    The discovery of a repeating fast radio burst (FRB) has led to the first precise localization, an association with a dwarf galaxy, and the identification of a coincident persistent radio source. However, further localizations are required to determine the nature of FRBs, the sources powering them, and the possibility of multiple populations. Here we investigate the use of associated persistent radio sources to establish FRB counterparts, taking into account the localization area and the source flux density. Due to the lower areal number density of radio sources compared to faint optical sources, robust associations can be achieved for less precise localizations as compared to direct optical host galaxy associations. For generally larger localizations that preclude robust associations, the number of candidate hosts can be reduced based on the ratio of radio-to-optical brightness. We find that confident associations with sources having a flux density of ∼0.01–1 mJy, comparable to the luminosity of the persistent source associated with FRB 121102 over the redshift range z ≈ 0.1–1, require FRB localizations of ≲20″. We demonstrate that even in the absence of a robust association, constraints can be placed on the luminosity of an associated radio source as a function of localization and dispersion measure (DM). For DM ≈1000 pc cm‑3, an upper limit comparable to the luminosity of the FRB 121102 persistent source can be placed if the localization is ≲10″. We apply our analysis to the case of the ASKAP FRB 170107, using optical and radio observations of the localization region. We identify two candidate hosts based on a radio-to-optical brightness ratio of ≳100. We find that if one of these is indeed associated with FRB 170107, the resulting radio luminosity (1029‑ 4 × 1030 erg s‑1 Hz‑1, as constrained from the DM value) is comparable to the luminosity of the FRB 121102 persistent source.

  1. Design of ultra-low power impulse radios

    CERN Document Server

    Apsel, Alyssa; Dokania, Rajeev

    2014-01-01

    This book covers the fundamental principles behind the design of ultra-low power radios and how they can form networks to facilitate a variety of applications within healthcare and environmental monitoring, since they may operate for years off a small battery or even harvest energy from the environment. These radios are distinct from conventional radios in that they must operate with very constrained resources and low overhead.  This book provides a thorough discussion of the challenges associated with designing radios with such constrained resources, as well as fundamental design concepts and practical approaches to implementing working designs.  Coverage includes integrated circuit design, timing and control considerations, fundamental theory behind low power and time domain operation, and network/communication protocol considerations.   • Enables detailed understanding of the design space for ultra-low power radio; • Provides detailed discussion and examples of the design of a practical low power ...

  2. Physical processes in extragalactic radio sources

    NARCIS (Netherlands)

    Carilli, CL; Perley, R; Harris, DE; Barthel, PD

    This paper summarizes extensive observational studies of the closest ultraluminous radio galaxy Cygnus A. These data are used to test jet theory for powering the double-lobed radio emitting structures. Issues addressed include: (i) jet stability, confinement, composition, and velocity, (ii) the

  3. 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...

  4. Radio emission from Jupiter

    International Nuclear Information System (INIS)

    Velusamy, T.

    1976-01-01

    The basic features of the different radio emissions from the planet Jupiter are reviewed. These radio emissions characterized into three types as thermal, decimetric and decametric, are discussed. The coherent emission mechanism for the origin of the decametric bursts and the acceleration mechanism for relativistic electrons in the decimetric radiation have not been properly understood. The emissions are much related to the magnetic field of Jupiter. The system III rotation period for Jupiter has been calculated as 092 55 m 29.74 S. (A.K.)

  5. Mathematical models for estimating radio channels utilization when ...

    African Journals Online (AJOL)

    Definition of the radio channel utilization indicator is given. Mathematical models for radio channels utilization assessment by real-time flows transfer in the wireless self-organized network are presented. Estimated experiments results according to the average radio channel utilization productivity with and without buffering of ...

  6. Survival and reproduction of radio-marked adult spotted owls.

    Science.gov (United States)

    C.C. Foster; E.D. Forsman; E.C. Meslow; G.S. Miller; J.A. Reid; F.F. Wagner; A.B. Carey; J.B. Lint

    1992-01-01

    We compared survival, reproduction, and body mass of radio-marked and non radio-marked spotted owls (Strix occidentalis) to determine if backpack radios influenced reproduction or survival. In most study areas and years, there were no differences (P > 0.05) in survival of males and females or in survival of radio-marked versus banded owls. There...

  7. A generalized measurement equation and van Cittert-Zernike theorem for wide-field radio astronomical interferometry

    Science.gov (United States)

    Carozzi, T. D.; Woan, G.

    2009-05-01

    We derive a generalized van Cittert-Zernike (vC-Z) theorem for radio astronomy that is valid for partially polarized sources over an arbitrarily wide field of view (FoV). The classical vC-Z theorem is the theoretical foundation of radio astronomical interferometry, and its application is the basis of interferometric imaging. Existing generalized vC-Z theorems in radio astronomy assume, however, either paraxiality (narrow FoV) or scalar (unpolarized) sources. Our theorem uses neither of these assumptions, which are seldom fulfiled in practice in radio astronomy, and treats the full electromagnetic field. To handle wide, partially polarized fields, we extend the two-dimensional (2D) electric field (Jones vector) formalism of the standard `Measurement Equation' (ME) of radio astronomical interferometry to the full three-dimensional (3D) formalism developed in optical coherence theory. The resulting vC-Z theorem enables full-sky imaging in a single telescope pointing, and imaging based not only on standard dual-polarized interferometers (that measure 2D electric fields) but also electric tripoles and electromagnetic vector-sensor interferometers. We show that the standard 2D ME is easily obtained from our formalism in the case of dual-polarized antenna element interferometers. We also exploit an extended 2D ME to determine that dual-polarized interferometers can have polarimetric aberrations at the edges of a wide FoV. Our vC-Z theorem is particularly relevant to proposed, and recently developed, wide FoV interferometers such as Low Frequency Array (LOFAR) and Square Kilometer Array (SKA), for which direction-dependent effects will be important.

  8. Mechanical design of SXLS (Superconducting X-ray Lithography Source) radio-frequency cavity

    Energy Technology Data Exchange (ETDEWEB)

    Mortazavi, P.; Sharma, S.; Keane, J.; Thomas, M.

    1989-01-01

    This paper presents the mechanical design of a Radio-Frequency (RF) cavity to be used on a compact storage ring for Superconducting X-ray Lithography Source (SXLS). Various design features of this cavity are discussed, including basic geometrical configuration, structural design, initial and operational tuning, vacuum multipactoring, power window, and damping of higher order modes. A second application of this cavity design for beam life extension in an existing storage ring is also described. 2 refs., 6 figs.

  9. Mechanical design of SXLS [Superconducting X-ray Lithography Source] radio-frequency cavity

    International Nuclear Information System (INIS)

    Mortazavi, P.; Sharma, S.; Keane, J.; Thomas, M.

    1989-01-01

    This paper presents the mechanical design of a Radio-Frequency (RF) cavity to be used on a compact storage ring for Superconducting X-ray Lithography Source (SXLS). Various design features of this cavity are discussed, including basic geometrical configuration, structural design, initial and operational tuning, vacuum multipactoring, power window, and damping of higher order modes. A second application of this cavity design for beam life extension in an existing storage ring is also described. 2 refs., 6 figs

  10. Ultra - Wideband, zero visual signature RF vest antenna for man-portable radios

    OpenAIRE

    Lebaric, Jovan E.; Adler, Richard W.; Limbert, Matthew E.

    2001-01-01

    This paper presents the recent research of the COMbat Wear INtegration (COMWIN) RF Vest antenna presented at MILCOM2000. This version of the ultra-wideband VHF/UHF (30 MHz to 500 MHz) vest antenna, designated as MK-III, is integrated into the existing dismounted Marine/Soldier Kevlar flak vest and has no visual signature. This antenna is one of the three COMWIN antennas developed at the Naval Postgraduate School (NPS) for the Joint Tactical Radio System applications. ...

  11. A repeating fast radio burst.

    Science.gov (United States)

    Spitler, L G; Scholz, P; 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

    2016-03-10

    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 measure (that is, the integrated column density of free electrons between source and telescope) and sky position as the original detections. The apparent non-repeating nature of these bursts has led to the suggestion that they originate in cataclysmic events. Here we report observations of ten additional bursts from the direction of the fast radio burst FRB 121102. These bursts have dispersion measures and sky positions consistent with the original burst. This unambiguously identifies FRB 121102 as repeating and demonstrates that its source survives the energetic events that cause the bursts. Additionally, the bursts from FRB 121102 show a wide range of spectral shapes that appear to be predominantly intrinsic to the source and which vary on timescales of minutes or less. Although there may be multiple physical origins for the population of fast radio bursts, these repeat bursts with high dispersion measure and variable spectra specifically seen from the direction of FRB 121102 support an origin in a young, highly magnetized, extragalactic neutron star.

  12. A radio monitoring survey of ultra-luminous X-ray sources

    Science.gov (United States)

    Körding, E.; Colbert, E.; Falcke, H.

    2005-06-01

    We present the results of a radio monitoring campaign to search for radio emission from nearby ultra-luminous X-ray sources (ULXs). These sources are bright off-nuclear X-ray point sources with luminosities exceeding LX > 1039 erg s-1. A well-defined sample of the 9 nearest ULXs has been monitored eight times over 5 months with the Very Large Array in A and B configuration. Our limiting sensitivity is ≈0.15 mJy (4σ) for radio flares and ≈60 μJy for continuous emission. In M 82 two ULXs seem to have coincident compact radio sources, which are probably supernova remnants. No continuous or flaring radio emission has been detected from any other ULX. Thus, ULXs do not generally emit steady-state radio emission above radio powers of 1.5 × 1017 W/Hz. The non-detections of the continuous emission are consistent with beamed or unbeamed radio emission from accreting black holes of ≤ 103 M⊙ based on the radio/X-ray correlation. Other published radio detections (M 82, NGC 5408) are also discussed in this context. Both detections are significantly above our detection limit. If ULXs have flaring radio emission above 4 × 1017 W/Hz we can give an upper limit on the duty cycle of the flares of 6%. This upper limit is in agreement with the observed number of flares in Galactic radio transients. Additionally we present a yet unreported radio double structure in the nearby low-luminosity AGN NGC 4736.

  13. 75 FR 76294 - Radio Broadcasting Services; Fairbanks, AK

    Science.gov (United States)

    2010-12-08

    ... FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 [DA 10-2211; MB Docket No. 10-81; RM-11600] Radio Broadcasting Services; Fairbanks, AK AGENCY: Federal Communications Commission. ACTION: Final rule. SUMMARY... Subjects in 47 CFR Part 73 Radio, Radio broadcasting. 0 For the reasons discussed in the preamble, the...

  14. Management of Distributed and Extendible Heterogeneous Radio Architectures

    DEFF Research Database (Denmark)

    Ramkumar, Venkata; Mihovska, Albena D.; Prasad, Neeli R.

    2009-01-01

    Wireless communication systems are dynamic by nature, which comes from several factors, namely: radio propagation impairments, traffic changes, interference conditions, user mobility, etc. In a heterogeneous environment, , the dynamic network behavior calls for a dynamic management of the radio...... resources; a process that associates a large number of parameters and quality/performance indicators that need to be set, measured, analyzed, and optimized. Radio-over-fiber (RoF) technology involves the use of optical fiber links to distribute radio frequency (RF) signals from a central location to remote...

  15. 78 FR 23150 - Commercial Radio Operators

    Science.gov (United States)

    2013-04-18

    ...'s privatized ship radio inspection program. * * * * * 0 3. Section 0.131 is amended by revising... this chapter), and the Commission's privatized ship radio inspection program (part 80 of this chapter... inspection to ships in accordance with applicable provisions of the Communications Act, the Safety Convention...

  16. The Beginnings of Australian Radio Astronomy

    Science.gov (United States)

    Sullivan, Woodruff T.

    The early stages of Australian radio astronomy, especially the first decade after World War II, are described in detail. These include the transition of the CSIRO Radiophysics Laboratory, under the leadership of Joseph Pawsey and Taffy Bowen, from a wartime laboratory in 1945 to, by 1950, the largest and one of the two most important radio astronomy groups in the world (with the Cavendish Laboratory at Cambridge University). The initial solar investigations are described, including discovery of the hot corona and development of the sea-cliff interferometer. During this same period painstaking `radio star' observations by John Bolton and colleagues led to the first suggested optical identifications of Taurus-A (the Crab Nebula), Centaurus-A (NGC 5128), and Virgo-A (M87). The factors that led to the extraordinary early success of the Radiophysics Laboratory are analyzed in detail, followed by discussion of how the situation changed significantly in the second decade of 1955-1965. Finally, the development of major Australian instruments, from the Parkes Radio Telescope (1961) to the Australia Telescope (1988), is briefly presented. This chapter is a direct reprint of the following research paper: Sullivan, W., 2005. The beginnings of Australian radio astronomy. Journal of Astronomical History and Heritage, 8, 11-32.

  17. Paradigms of modern radio-biology

    International Nuclear Information System (INIS)

    Grodzins'kij, D.M.

    2005-01-01

    The basic paradigms of modern radio-biology are considered as models of pictures of essence of radio-biology problems and methods of their decision. It is marked on absolute heuristics of these ascending conceptual assertions and their assistance to subsequent development of experimental science. That has the concrete display in the decision of actual tasks of protection of people from action of ionizing radiation

  18. THE RADIO ACTIVITY-ROTATION RELATION OF ULTRACOOL DWARFS

    International Nuclear Information System (INIS)

    McLean, M.; Berger, E.; Reiners, A.

    2012-01-01

    We present a new radio survey of about 100 late-M and L dwarfs undertaken with the Very Large Array. The sample was chosen to explore the role of rotation in the radio activity of ultracool dwarfs. As part of the survey we discovered radio emission from three new objects, 2MASS J 0518113 – 310153 (M6.5), 2MASS J 0952219 – 192431 (M7), and 2MASS J 1314203 + 132001 (M7), and made an additional detection of LP 349-25 (M8). Combining the new sample with results from our previous studies and from the literature, we compile the largest sample to date of ultracool dwarfs with radio observations and measured rotation velocities (167 objects). In the spectral type range M0-M6 we find a radio activity-rotation relation, with saturation at L rad /L bol ≈ 10 –7.5 above vsin i ≈ 5 km s –1 , similar to the relation in Hα and X-rays. However, at spectral types ∼> M7 the ratio of radio to bolometric luminosity increases significantly regardless of rotation velocity, and the scatter in radio luminosity increases. In particular, while the most rapid rotators (vsin i ∼> 20 km s –1 ) exhibit 'super-saturation' in X-rays and Hα, this effect is not seen in the radio. We also find that ultracool dwarfs with vsin i ∼> 20 km s –1 have a higher radio detection fraction by about a factor of three compared to objects with vsin i ∼ –1 . When measured in terms of the Rossby number (Ro), the radio activity-rotation relation follows a single trend and with no apparent saturation from G to L dwarfs and down to Ro ∼ 10 –3 ; in X-rays and Hα there is clear saturation at Ro ∼ rad /R 2 * ) as a function of Ro. The continued role of rotation in the overall level of radio activity and in the fraction of active sources, and the single trend of L rad /L bol and L rad /R 2 * as a function of Ro from G to L dwarfs, indicates that rotation effects are important in regulating the topology or strength of magnetic fields in at least some fully convective dwarfs. The fact that

  19. Cognitive radio application for vehicular ad hoc networks (VANETS

    Directory of Open Access Journals (Sweden)

    Miladić Suzana D.

    2016-01-01

    Full Text Available This paper presents the application of cognitive radio technology in vehicular ad-hoc networks aimed to improve the communications between vehicles themselves as well as between vehicles and roadside infrastructure. Due to dynamic approach of spectrum access, cognitive radio is a technology that enables more efficient usage of radio-frequency spectrum. We review actual approaches and discuss research challenges related to the use of cognitive radio technology in vehicular ad hoc networks with emphasis on architecture, spectrum management as well as QoS optimization. The researching on cognitive radio application in vehicular networks is still developing and there are not many experimental platforms due to their complex setups. Some related research projects and cognitive radio realizations are provided in this paper.

  20. Solar observations with a low frequency radio telescope

    Science.gov (United States)

    Myserlis, I.; Seiradakis, J.; Dogramatzidis, M.

    2012-01-01

    We have set up a low frequency radio monitoring station for solar bursts at the Observatory of the Aristotle University in Thessaloniki. The station consists of a dual dipole phased array, a radio receiver and a dedicated computer with the necessary software installed. The constructed radio receiver is based on NASA's Radio Jove project. It operates continuously, since July 2010, at 20.1 MHz (close to the long-wavelength ionospheric cut-off of the radio window) with a narrow bandwidth (~5 kHz). The system is properly calibrated, so that the recorded data are expressed in antenna temperature. Despite the high interference level of an urban region like Thessaloniki (strong broadcasting shortwave radio stations, periodic experimental signals, CBs, etc), we have detected several low frequency solar radio bursts and correlated them with solar flares, X-ray events and other low frequency solar observations. The received signal is monitored in ordinary ASCII format and as audio signal, in order to investigate and exclude man-made radio interference. In order to exclude narrow band interference and calculate the spectral indices of the observed events, a second monitoring station, working at 36 MHz, is under construction at the village of Nikiforos near the town of Drama, about 130 km away of Thessaloniki. Finally, we plan to construct a third monitoring station at 58 MHz, in Thessaloniki. This frequency was revealed to be relatively free of interference, after a thorough investigation of the region.

  1. Broadcasting studios Radio Bremen becomes residence rehabilitation clinic. Energy efficient retrofitting with economic building services technology; Funkhaus Radio Bremen wird Residenz Reha-Klinik. Energieeffiziente Sanierung mit wirtschaftlicher Gebaeudetechnik

    Energy Technology Data Exchange (ETDEWEB)

    Hinz, Thomas [Siemens AG, Bremen (Germany). Building Technologies Div.

    2012-07-01

    Hardly any building project is as sustainable as the rededication of a building. A recent example: The former site of Radio Bremen in the district Schwachhausen with approximately 10,000 square meters of studios, production facilities and offices were committed to the residence rehabilitation clinic with 200 beds and 100 outpatient rehab places. In order to support the economic efficiency of this measure, the existing infrastructure of the heating technology, ventilation technology and air conditioning technology was adopted and modernized.

  2. Effects of fecal sampling on preanalytical and analytical phases in quantitative fecal immunochemical tests for hemoglobin.

    Science.gov (United States)

    Rapi, Stefano; Berardi, Margherita; Cellai, Filippo; Ciattini, Samuele; Chelazzi, Laura; Ognibene, Agostino; Rubeca, Tiziana

    2017-07-24

    Information on preanalytical variability is mandatory to bring laboratories up to ISO 15189 requirements. Fecal sampling is greatly affected by lack of harmonization in laboratory medicine. The aims of this study were to obtain information on the devices used for fecal sampling and to explore the effect of different amounts of feces on the results from the fecal immunochemical test for hemoglobin (FIT-Hb). Four commercial sample collection devices for quantitative FIT-Hb measurements were investigated. The volume of interest (VOI) of the probes was measured from diameter and geometry. Quantitative measurements of the mass of feces were carried out by gravimetry. The effects of an increased amount of feces on the analytical environment were investigated measuring the Hb values with a single analytical method. VOI was 8.22, 7.1 and 9.44 mm3 for probes that collected a target of 10 mg of feces, and 3.08 mm3 for one probe that targeted 2 mg of feces. The ratio between recovered and target amounts of devices ranged from 56% to 121%. Different changes in the measured Hb values were observed, in adding increasing amounts of feces in commercial buffers. The amounts of collected materials are related to the design of probes. Three out 4 manufacturers declare the same target amount using different sampling volumes and obtaining different amounts of collected materials. The introduction of a standard probes to reduce preanalytical variability could be an useful step for fecal test harmonization and to fulfill the ISO 15189 requirements.

  3. Future Standardization of Space Telecommunications Radio System with Core Flight System

    Science.gov (United States)

    Briones, Janette C.; Hickey, Joseph P.; Roche, Rigoberto; Handler, Louis M.; Hall, Charles S.

    2016-01-01

    NASA Glenn Research Center (GRC) is integrating the NASA Space Telecommunications Radio System (STRS) Standard with the Core Flight System (cFS), an avionics software operating environment. The STRS standard provides a common, consistent framework to develop, qualify, operate and maintain complex, reconfigurable and reprogrammable radio systems. The cFS is a flexible, open architecture that features a plugand- play software executive called the Core Flight Executive (cFE), a reusable library of software components for flight and space missions and an integrated tool suite. Together, STRS and cFS create a development environment that allows for STRS compliant applications to reference the STRS application programmer interfaces (APIs) that use the cFS infrastructure. These APIs are used to standardize the communication protocols on NASAs space SDRs. The cFS-STRS Operating Environment (OE) is a portable cFS library, which adds the ability to run STRS applications on existing cFS platforms. The purpose of this paper is to discuss the cFS-STRS OE prototype, preliminary experimental results performed using the Advanced Space Radio Platform (ASRP), the GRC S- band Ground Station and the SCaN (Space Communication and Navigation) Testbed currently flying onboard the International Space Station (ISS). Additionally, this paper presents a demonstration of the Consultative Committee for Space Data Systems (CCSDS) Spacecraft Onboard Interface Services (SOIS) using electronic data sheets (EDS) inside cFE. This configuration allows for the data sheets to specify binary formats for data exchange between STRS applications. The integration of STRS with cFS leverages mission-proven platform functions and mitigates barriers to integration with future missions. This reduces flight software development time and the costs of software-defined radio (SDR) platforms. Furthermore, the combined benefits of STRS standardization with the flexibility of cFS provide an effective, reliable and

  4. Radio Interoperability: There Is More to It Than Hardware

    National Research Council Canada - National Science Library

    Hutchins, Susan G; Timmons, Ronald P

    2007-01-01

    Radio Interoperability: The Problem *Superfluous radio transmissions contribute to auditory overload of first responders -Obscure development of an accurate operational picture for all involved -Radio spectrum is a limited commodity once...

  5. 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.

  6. 75 FR 10439 - Cognitive Radio Technologies and Software Defined Radios

    Science.gov (United States)

    2010-03-08

    ... petition could not through the exercise of due diligence have learned of the facts in question prior to... to a wide variety of radio services, including safety-of-life services--the Commission holds the...

  7. Reconfigurable, Cognitive Software-Defined Radio

    Science.gov (United States)

    Bhat, Arvind

    2015-01-01

    Software-defined radio (SDR) technology allows radios to be reconfigured to perform different communication functions without using multiple radios to accomplish each task. Intelligent Automation, Inc., has developed SDR platforms that switch adaptively between different operation modes. The innovation works by modifying both transmit waveforms and receiver signal processing tasks. In Phase I of the project, the company developed SDR cognitive capabilities, including adaptive modulation and coding (AMC), automatic modulation recognition (AMR), and spectrum sensing. In Phase II, these capabilities were integrated into SDR platforms. The reconfigurable transceiver design employs high-speed field-programmable gate arrays, enabling multimode operation and scalable architecture. Designs are based on commercial off-the-shelf (COTS) components and are modular in nature, making it easier to upgrade individual components rather than redesigning the entire SDR platform as technology advances.

  8. 50 CFR 300.37 - Radio monitoring.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 7 2010-10-01 2010-10-01 false Radio monitoring. 300.37 Section 300.37 Wildlife and Fisheries INTERNATIONAL FISHING AND RELATED ACTIVITIES INTERNATIONAL FISHERIES REGULATIONS South Pacific Tuna Fisheries § 300.37 Radio monitoring. The international distress frequency, 2.182 mHz...

  9. Radio monitoring problems, methods, and equipment

    CERN Document Server

    Rembovsky, Anatoly; Kozmin, Vladimir; Smolskiy, Sergey

    2009-01-01

    Offers a unified approach to fundamental aspects of Automated Radio Monitoring (ARM). This book discusses the development, modeling, design, and manufacture of ARM systems. It provides classification and descriptions of modern high-efficient hardware-software ARM equipment, including the equipment for detection and radio direction-finding.

  10. STUDY ON ROLE OF RADIO FOR RURAL EDUCATION IN PAKISTAN

    Directory of Open Access Journals (Sweden)

    Nabi Bux JUMANI

    2009-10-01

    Full Text Available Radio is a mean not only for information and entertainment but also for education. Radio is being used for educational purposes all over the world. In Pakistan it is also a medium of communication. Pakistan broadcasting corporation has started broadcasting educational programs of Allama Iqbal Open University. There is no denying the fact that educational broadcasting in Pakistan is being run successfully. The rural population of the country is getting benefit from the educational programmes of the radio.The main aim of the study was to examine the effectiveness of educational radio and its various strategies being applied for rural education. The study was delimited the radio listeners, radio producers/comperes and social workers/opinion leaders. The masters list of listeners was obtained from Radio Station, Hyderabad. The second sample was radio producers/comperes whereas the third sample was social workers/opinion leaders. The tool used in this study was questionnaires. It was found that the majority of the listeners possessed radio sets and was getting benefit from the educational programmes of radio. The programmes were informative and motivating. The strategies of radio for rural education were appreciable because these infused mobility, widened horizon of rural people and focused attention on the goals and problems of rural people. It could be used to enhance literacy (through distance and non-formal education.the producers/comperes were found keenly interested in their job. It was revealed that priority was given to education and rural development programmes of radio. Programmes needed detail and summary at the end. Furthermore language was not easy. Mobile radio station was needed for rural educational programme to cater to the needs of far flung areas. School broadcast (distance and non-formal teaching was the need of the day. Social workers/opinion leaders opined that there was need of developing self reliance. Radio provides guidance

  11. Spectrum access and management for cognitive radio networks

    CERN Document Server

    2017-01-01

    This book presents cutting-edge research contributions that address various aspects of network design, optimization, implementation, and application of cognitive radio technologies. It demonstrates how to make better utilization of the available spectrum, cognitive radios and spectrum access to achieve effective spectrum sharing between licensed and unlicensed users. The book provides academics and researchers essential information on current developments and future trends in cognitive radios for possible integration with the upcoming 5G networks. In addition, it includes a brief introduction to cognitive radio networks for newcomers to the field.

  12. X-RAYS FROM A RADIO-LOUD COMPACT BROAD ABSORPTION LINE QUASAR 1045+352 AND THE NATURE OF OUTFLOWS IN RADIO-LOUD BROAD ABSORPTION LINE QUASARS

    International Nuclear Information System (INIS)

    Kunert-Bajraszewska, Magdalena; Katarzynski, Krzysztof; Siemiginowska, Aneta; Janiuk, Agnieszka

    2009-01-01

    We present new results on X-ray properties of radio-loud broad absorption line (BAL) quasars and focus on broadband spectral properties of a high-ionization BAL (HiBAL) compact steep spectrum (CSS) radio-loud quasar 1045+352. This HiBAL quasar has a very complex radio morphology indicating either strong interactions between a radio jet and the surrounding interstellar medium or a possible re-start of the jet activity. We detected 1045+352 quasar in a short 5 ksec Chandra ACIS-S observation. We applied theoretical models to explain spectral energy distribution of 1045+352 and argue that non-thermal, inverse-Compton (IC) emission from the innermost parts of the radio jet can account for a large fraction of the observed X-ray emission. In our analysis, we also consider a scenario in which the observed X-ray emission from radio-loud BAL quasars can be a sum of IC jet X-ray emission and optically thin corona X-ray emission. We compiled a sample of radio-loud BAL quasars that were observed in X-rays to date and report no correlation between their X-ray and radio luminosity. However, the radio-loud BAL quasars show a large range of X-ray luminosities and absorption columns. This is consistent with the results obtained earlier for radio-quiet BAL quasars and may indicate an orientation effect in BAL quasars or more complex dependence between X-ray emission, radio emission, and an orientation based on the radio morphology.

  13. Solar energetic particles and radio burst emission

    Directory of Open Access Journals (Sweden)

    Miteva Rositsa

    2017-01-01

    Full Text Available We present a statistical study on the observed solar radio burst emission associated with the origin of in situ detected solar energetic particles. Several proton event catalogs in the period 1996–2016 are used. At the time of appearance of the particle origin (flare and coronal mass ejection we identified radio burst signatures of types II, III and IV by inspecting dynamic radio spectral plots. The information from observatory reports is also accounted for during the analysis. The occurrence of solar radio burst signatures is evaluated within selected wavelength ranges during the solar cycle 23 and the ongoing 24. Finally, we present the burst occurrence trends with respect to the intensity of the proton events and the location of their solar origin.

  14. FeltRadio: Sensing and Making Sense of Wireless Traffic

    DEFF Research Database (Denmark)

    Gronvall, Erik; Fritsch, Jonas; Vallgårda, Anna

    2016-01-01

    Radio waves surround us but still they remain largely undetected by our senses. Unless we use specifically tuned hardware, such as FM radios, cell phones or WiFi modems, human beings cannot perceive wirelessly transmitted data. This paper presents FeltRadio, a portable and wireless technology...... that makes it possible to turn radio signals into visual and tactile stimuli as a form of sensorial augmentation. FeltRadio explores and makes us reflect upon what it would be like if we could sense, and feel, wireless traffic such as WiFi or Bluetooth. We present the technological design behind Felt...

  15. 14 CFR 99.9 - Radio requirements.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Radio requirements. 99.9 Section 99.9 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES SECURITY CONTROL OF AIR TRAFFIC General § 99.9 Radio requirements. (a) A...

  16. CORRELATIONS OF QUASAR OPTICAL SPECTRA WITH RADIO MORPHOLOGY

    International Nuclear Information System (INIS)

    Kimball, Amy E.; Ivezic, Zeljko; Wiita, Paul J.; Schneider, Donald P.

    2011-01-01

    Using the largest homogeneous quasar sample with high-quality optical spectra and robust radio morphology classifications assembled to date, we investigate relationships between radio and optical properties with unprecedented statistical power. The sample consists of 4714 radio quasars from FIRST with S 20 ≥ 2 mJy and with spectra from the Sloan Digital Sky Survey (SDSS). Radio morphology classes include core-only (core), core-lobe (lobe), core-jet (jet), lobe-core-lobe (triple), and double-lobe. Electronic tables of the quasar samples, along with spectral composites for individual morphology classes, are made available. We examine the optical colors of these subsamples and find that radio quasars with core emission unresolved by FIRST (on ∼5'' scale) have a redder color distribution than radio-quiet quasars (S 20 ∼ I ) are correlated, which supports the hypothesis that both parameters are indicative of line-of-sight orientation. We investigate spectral line equivalent widths (EWs) as a function of R and R I , including the O [III] narrow line doublet and the C IV λ1549 and Mg II λ2799 broad lines. We find that the rest EWs of the broad lines correlate positively with R I at the 4σ-8σ level. However, we find no strong dependence of EW on R, in contrast to previously published results. A possible interpretation of these results is that EWs of quasar emission lines increase as the line-of-sight angle to the radio-jet axis decreases. These results are in stark contrast to commonly accepted orientation-based theories, which suggest that continuum emission should increase as the angle to the radio-jet axis decreases, resulting in smaller EWs of emission lines (assumed isotropic). Finally, we observe the Baldwin effect in our sample and find that it does not depend strongly on quasar radio morphology.

  17. Extended radio emission and the nature of blazars

    International Nuclear Information System (INIS)

    Antonucci, R.R.J.; Ulvestad, J.S.

    1985-01-01

    The VLA has been used at 20 cm to map all 23 of the 54 confirmed blazars listed in the Angel and Stockman review paper that had not been mapped before at high resolution. (Blazars include BL Lac objects and optically violently variable quasars.) In addition, data on most of the previously mapped blazars have been reprocessed in order to achieve higher dynamic range. Extended emission has been detected associated with 49 of the 54 objects. The extended radio emission has been used to test the hypothesis that blazars are normal radio galaxies and radio quasars viewed along the jet axes. We find that blazars have substantial extended power, consistent with this hypothesis. Many have extended powers as high as the luminous Fanaroff-Riley class 2 radio doubles. The projected linear sizes are small, as expected from foreshortening of the extended sources, and many blazars have the expected core-halo morphology. There are also several small doubles, a head-tail source, and some one-sided sources, and these could be in cases where the line of sight is slightly off the jet axis, or projections of asymmetrical radio galaxies and quasars. The ratio of core to extended radio emission has been studied as a possible indicator of viewing aspect or beaming intensity. It is found to correlate with optical polarization, optical and radio core variability, and one-sided radio morphology. We can go beyond these consistency checks and work toward a proof of the hypothesis under discussion. The flux from the extended emission alone is sufficient in some blazars to qualify them for inclusion in the 3C and 4C catalogs. Suppose that the radio core emission is anisotropic, but the extended emission is predominantly isotropic. The isotropy of the extended emission implies that these blazars would be in the catalogs even if viewed from the side

  18. The cluster environments of powerful, high-redshift radio galaxies

    International Nuclear Information System (INIS)

    Yates, M.G.

    1989-01-01

    We present deep imaging of a sample of 25 powerful radio galaxies in the redshift range 0.15 gr ) about each source, a measure of the richness of environment. The powerful radio galaxies in this sample at z>0.3 occupy environments nearly as rich on average as Abell class 0 clusters of galaxies, about three times richer than the environments of the z<0.3 radio galaxies. This trend in cluster environment is consistent with that seen in radio-loud quasars over the same redshift range. Our previous work on the 3CR sample suggested that the fundamental parameter which correlates with the richness of environment might be the radio luminosity of the galaxy, rather than its redshift. Our direct imaging confirms that the most powerful radio galaxies do inhabit rich environments. (author)

  19. Radio astronomy on the moon

    International Nuclear Information System (INIS)

    Burns, J.O.; Asbell, J.

    1987-01-01

    The advantages and opportunities for radio astronomy on the moon during the early to mid 21st century are reviewed. In particular, it is argued that the lack of atmosphere, the extremely low seismic activity, the low RF background, and the natural cryogenic environment make the moon (particularly the far side and the poles) a nearly ideal locale for submillimeter/FIR to VLF (below 10 MHz) radio astronomy. 22 references

  20. Historic Radio Astronomy Working Group

    Science.gov (United States)

    2007-06-01

    This special issue of Astronomische Nachrichten contains the proceedings of a session of the Historic Radio Astronomy Working Group of the International Astronomical Union that took place during the 26th General Assembly of the IAU in Prague on 17th August 2006. In addition to the talks presented in Prague some contributions were solicited to give a more complete overview of `The Early History of European Radio Astronomy'.

  1. RADIO NOISE ADVANCES SEXUAL MATURITY

    African Journals Online (AJOL)

    ansistf-lewis

    Mean age at first egg for the radio birds (143 d) was 13 d significantly earlier than controls, but body weight at ... the first 8 h of a 12-h photoperiod with radio noise, to leave only 4 h of light (4L:20D), supported rates of lay ... Age (AFE) and body weight at, and weight of, first egg were recorded for individual birds, and, after a.

  2. The invisible universe the story of radio astronomy

    CERN Document Server

    Verschuur, Gerrit

    2015-01-01

    Hidden from human view, accessible only to sensitive receivers attached to huge radio telescopes, the invisible universe beyond our senses continues to fascinate and intrigue our imaginations. Closer to home, in the Milky Way galaxy, radio astronomers listen patiently to the ticking of pulsars that tell of star death and states of matter of awesome densities. All of this happens out there in the universe hidden from our eyes, even when aided by the Hubble Space Telescope. This is the story of radio astronomy, of how radio waves are generated by stars, supernova, quasars, colliding galaxies and by the very beginnings of the universe itself. The author discusses what radio astronomers are doing in the New Mexico desert, in a remote valley in Puerto Rico, and in the green Pocahontas Valley in West Virginia, as well as dozens of other remote sites around the world. With each of these observatories, the scientists collect and analyze their data, "listening" to the radio signals from space in order to learn what, ...

  3. RF Spectrum Sensing Based on an Overdamped Nonlinear Oscillator Ring for Cognitive Radios

    Directory of Open Access Journals (Sweden)

    Zhi-Ling Tang

    2016-06-01

    Full Text Available Existing spectrum-sensing techniques for cognitive radios require an analog-to-digital converter (ADC to work at high dynamic range and a high sampling rate, resulting in high cost. Therefore, in this paper, a spectrum-sensing method based on a unidirectionally coupled, overdamped nonlinear oscillator ring is proposed. First, the numerical model of such a system is established based on the circuit of the nonlinear oscillator. Through numerical analysis of the model, the critical condition of the system’s starting oscillation is determined, and the simulation results of the system’s response to Gaussian white noise and periodic signal are presented. The results show that once the radio signal is input into the system, it starts oscillating when in the critical region, and the oscillating frequency of each element is fo/N, where fo is the frequency of the radio signal and N is the number of elements in the ring. The oscillation indicates that the spectrum resources at fo are occupied. At the same time, the sampling rate required for an ADC is reduced to the original value, 1/N. A prototypical circuit to verify the functionality of the system is designed, and the sensing bandwidth of the system is measured.

  4. AUTOMATIC RECOGNITION OF CORONAL TYPE II RADIO BURSTS: THE AUTOMATED RADIO BURST IDENTIFICATION SYSTEM METHOD AND FIRST OBSERVATIONS

    International Nuclear Information System (INIS)

    Lobzin, Vasili V.; Cairns, Iver H.; Robinson, Peter A.; Steward, Graham; Patterson, Garth

    2010-01-01

    Major space weather events such as solar flares and coronal mass ejections are usually accompanied by solar radio bursts, which can potentially be used for real-time space weather forecasts. Type II radio bursts are produced near the local plasma frequency and its harmonic by fast electrons accelerated by a shock wave moving through the corona and solar wind with a typical speed of ∼1000 km s -1 . The coronal bursts have dynamic spectra with frequency gradually falling with time and durations of several minutes. This Letter presents a new method developed to detect type II coronal radio bursts automatically and describes its implementation in an extended Automated Radio Burst Identification System (ARBIS 2). Preliminary tests of the method with spectra obtained in 2002 show that the performance of the current implementation is quite high, ∼80%, while the probability of false positives is reasonably low, with one false positive per 100-200 hr for high solar activity and less than one false event per 10000 hr for low solar activity periods. The first automatically detected coronal type II radio burst is also presented.

  5. La radio universitaria en el siglo XXI: perspectiva hispano-francesa

    Directory of Open Access Journals (Sweden)

    Miguel Ángel Ortíz Sobrino

    2014-01-01

    Full Text Available La radio universitaria de tipo “radios libres, radios asociativas” en Francia se remonta a la década de los 60. La experiencia pionera dentro de este marco en territorio francés puede considerarse la aparición, en 1969, de Radio Campus Lille. En el caso español, fue la Universidad de la Laguna, en 1987, la primera institución universitaria que promovió las primeras emisiones universitarias realizadas por los estudiantes del Colegio Mayor San Fernando, aunque los primeros referentes pueden situarse en las emisiones de la UNED a través de Radio 3, a partir de 1979. En la actualidad, las radios universitarias francesas están agrupadas en la Red Radio Campus France. Por su parte, las radios universitarias españolas se agrupan en la Asociación de Radios Universitarias (ARU, creada en 2011. Aunque el número de estaciones radiofónicas universitarias es más o menos similar en ambos países, la realidad y desarrollo es bastante diferente. En este artículo se analiza y se hace una revisión crítica de la situación actual de la radio universitaria en Francia y España.

  6. Part of the oxidative stress in the development of radio-induced cell effects at cutaneous level: application to accidental localised irradiations; Role du stress oxydatif dans le developpement des effets cellulaires radio-induits au niveau cutane: application aux irradiations localisees accidentelles

    Energy Technology Data Exchange (ETDEWEB)

    Carine, Laurent

    2005-10-15

    The objective of our study was to answer to the following questions: does the initial radio-induced oxidative stress lead to the accumulation of DNA damages in the low renewal cells (fibroblasts, endothelial cells) that could be responsible of delayed effects; does it exist delayed oxidative phenomena and era they implied in the delayed effects arising; does it exist a phenomenon of premature senescence; does it exist a premature senescence phenomenon that could lead to an accumulation of damages before the cell death; what are the action mechanisms of the association pentoxifylline/{alpha}-tocopherol. (N.C.)

  7. `Zwicky's Nonet': a compact merging ensemble of nine galaxies and 4C 35.06, a peculiar radio galaxy with dancing radio jets

    Science.gov (United States)

    Biju, K. G.; Bagchi, Joydeep; Ishwara-Chandra, C. H.; Pandey-Pommier, M.; Jacob, Joe; Patil, M. K.; Kumar, P. Sunil; Pandge, Mahadev; Dabhade, Pratik; Gaikwad, Madhuri; Dhurde, Samir; Abraham, Sheelu; Vivek, M.; Mahabal, Ashish A.; Djorgovski, S. G.

    2017-10-01

    We report the results of our radio, optical and infrared studies of a peculiar radio source 4C 35.06, an extended radio-loud active galactic nucleus (AGN) at the centre of galaxy cluster Abell 407 (z = 0.047). The central region of this cluster hosts a remarkably tight ensemble of nine galaxies, the spectra of which resemble those of passive red ellipticals, embedded within a diffuse stellar halo of ˜1 arcmin size. This system (named 'Zwicky's Nonet') provides unique and compelling evidence for a multiple-nucleus cD galaxy precursor. Multifrequency radio observations of 4C 35.06 with the Giant Meterwave Radio Telescope (GMRT) at 610, 235 and 150 MHz reveal a system of 400-kpc scale helically twisted and kinked radio jets and outer diffuse lobes. The outer extremities of jets contain extremely steep-spectrum (spectral index -1.7 to -2.5) relic/fossil radio plasma with a spectral age of a few ×(107-108) yr. Such ultra-steep spectrum relic radio lobes without definitive hotspots are rare and they provide an opportunity to understand the life cycle of relativistic jets and physics of black hole mergers in dense environments. We interpret our observations of this radio source in the context of growth of its central black hole, triggering of its AGN activity and jet precession, all possibly caused by galaxy mergers in this dense galactic system. A slow conical precession of the jet axis due to gravitational perturbation between interacting black holes is invoked to explain the unusual jet morphology.

  8. Blazars with arcminute-scale radio halos

    International Nuclear Information System (INIS)

    Ulvestad, J.S.; Antonucci, R.R.J.; Space Telescope Science Institute, Baltimore, MD)

    1986-01-01

    About 10-arcsec resolution 20-cm wavelength maps are presented for three nearby BL Lac objects: Mkn 180, whose halo has a linear size of 85 kpc, 2155-304, with a halo about 375 kpc across, and 1727 + 502, whose one-sided diffuse emission extends to a distance of about 145 kpc from its radio core. Little evidence is found for strong radio variability in the cores of the three blazars; these and other results obtained are consistent with the assertion that the three objects should be classified as normal low luminosity double radio galaxies with optically dull nuclei, if seen from other directions. 20 references

  9. How To Tell Your Literacy Stories through Radio.

    Science.gov (United States)

    Martini, Michael A.

    This paper offers advice to educators on how to tell their literacy stories through the medium of radio. It suggests educators examine their story idea closely and decide if radio is the best medium. It also suggests that educators should become familiar with the radio stations in the local market and get to know the personnel at the particular…

  10. Centralized Radio Resource Management for 5G small cells as LSA enabler

    OpenAIRE

    Carrasco, Oscar; Miatton, Federico; Diaz, Salva; Herzog, Uwe; Frascolla, Valerio; Fitch, Michael; Briggs, Keith; Miscopein, Benoit; de Domenico, Antonio; Georgakopoulos, Andreas

    2017-01-01

    The stringent requirements defined for 5G systems drive the need to promote new paradigms to the existing cellular networks. Dense and ultra-dense networks based on small cells, together with new spectrum sharing schemes seem to be key enabling technologies for emerging 5G mobile networks. This article explores the vision of the SPEED-5G project, analyzing the ability of a Centralized Radio Resource Management entity to support the Licensed Shared Access spectrum sharing framework in a deploy...

  11. Radio-detection of ultra-high energy cosmic rays. Analysis, simulation and interpretation

    International Nuclear Information System (INIS)

    Marin, V.

    2011-01-01

    Despite the use of giant detectors suitable for low flux beyond 1018 eV, the origin of ultra energy cosmic rays, remains unclear. In the 60', the radio-detection of air shower is proposed as a complementary technique to the ground particle detection and to the fluorescence method. A revival of this technique took place in the 2000's in particular with CODALEMA experiment. The first results show both a strong dependence of the signal to the geomagnetic field and a strong correlation between energy estimated by the radio-detectors and by particle detectors. The new generation of autonomous detectors created by the CODALEMA collaboration indicates that it is now possible to detect air showers autonomously. Due to the expected performances (a nearly 100% duty cycle, a signal generated by the complete shower, simplicity and low cost of a detector), it is possible to consider to deploy this technique for the future large arrays. In order to interpret experimental data, a simulation tool, SELFAS, is developed in this wok. This simulation code allowed us to highlight the existence of a second radio-emission mechanism. A first interpretation of the longitudinal profile as an observable of a privileged instant of the shower development is also proposed, which could give an estimation of the nature of the primary. (author)

  12. Radio and X-ray emission from supernova remnants

    International Nuclear Information System (INIS)

    Asvarova, A.I.; Novruzova, H.I.; Ahmedova, S.I.

    2010-01-01

    In this paper it was studied the statistical correlation between radio and X-ray emissions from shell-type supernova remnants (SNR). The primary aim of this study is to test the model of radio emission of shell-type SNRs presented by one of the authors. Based on this model of radio emission, by using the Monte Carlo techniques we have simulated statistical relations radio - X-ray luminosities (not surface brightnesses) which then were compared with the observations. X-ray emission is assumed to be thermal. To have a uniform statistical material it was used observational data on the SNRs in Magellanic Clouds

  13. Radio resource management using geometric water-filling

    CERN Document Server

    He, Peter; Zhou, Sheng; Niu, Zhisheng

    2014-01-01

    This brief introduces the fundamental theory and development of managing radio resources using a water-filling algorithm that can optimize system performance in wireless communication. Geometric Water-Filling (GWF) is a crucial underlying tool in emerging communication systems such as multiple input multiple output systems, cognitive radio systems, and green communication systems. Early chapters introduce emerging wireless technologies and provide a detailed analysis of water-filling. The brief investigates single user and multi-user issues of radio resource management, allocation of resources

  14. American-English on Philippine Radio and Television

    OpenAIRE

    江中, 八郎; Hachiro, Enaka

    1998-01-01

    Both English and Filipino are official languages in the Philippines. However, if we take a walk in downtown Manila, we notice that Radio and Television broadcasting, newspapers and journals are in English, their expression and the accents of trained Filipino announcers are indeed very American. At present, radio signals are received in 95% of the whole archipelago, with more than 70% of the total Philippine households owning radios. On the other hand, only about 35% of all households own TV s...

  15. Radio Frequency Interference Mitigation

    Science.gov (United States)

    An, T.; Chen, X.; Mohan, P.; Lao, B. Q.

    2017-09-01

    The observational facilities of radio astronomy keep constant upgrades and developments to achieve better capabilities including increasing the time of the data recording and frequency resolutions, and increasing the receiving and recording bandwidth. However in contrast, only a limited spectrum resource has been allocated to radio astronomy by the International Telecommunication Union, resulting in that the radio observational instrumentations are inevitably exposed to undesirable radio frequency interference (RFI) signals which originate mainly from the terrestrial human activity and are becoming stronger with time. RFIs degrade the quality of data and even lead to invalid data. The impact of RFIs on scientific outcome becomes more and more serious. In this article, the requirement for RFI mitigation is motivated, and the RFI characteristics, mitigation techniques, and strategies are reviewed. The mitigation strategies adopted at some representative observatories, telescopes, and arrays are also introduced. The advantages and shortcomings of the four classes of RFI mitigation strategies are discussed and presented, applicable at the connected causal stages: preventive, pre-detection, pre-correlation, and post-correlation. The proper identification and flagging of RFI is the key to the reduction of data loss and improvement in data quality, and is also the ultimate goal of developing RFI mitigation technique. This can be achieved through a strategy involving a combination of the discussed techniques in stages. The recent advances in the high speed digital signal processing and high performance computing allow for performing RFI excision of the large data volumes generated from large telescopes or arrays in both real time and offline modes, aiding the proposed strategy.

  16. Radio Astronomy in Malaysia: Current Status and Outreach Activities

    Science.gov (United States)

    Hashim, N.; Abidin, Z. Z.; Ibrahim, U. F. S. U.; Umar, R.; Hassan, M. S. R.; Rosli, Z.; Hamidi, Z. S.; Ibrahim, Z. A.

    2011-12-01

    In this paper, we will present the current status of radio astronomical research and outreach in Malaysia. We will also present a short history of our research group, which is currently the only radio astronomical facility in Malaysia. Our group is called the Radio Cosmology Research Lab and was established in 2005 by Dr Zamri Zainal Abidin and Prof Dr Zainol Abidin Ibrahim. We will discuss the future plans for this group including our keen interest in being part of a more global network of radio astronomers. We are already an active member of the South-East Asia Astronomy Network (SEAAN) and aims to have a radio astronomical facility in order to join the Global Very Long Baseline Interferometer (VLBI) as well becoming a research hub for the future Square Kilometer Array (SKA) project. We will also present some of the scientific goals of our group including providing a platform for radio astronomers to be able to do observations of weak and high red-shifted radio objects such as galaxy clusters and supernovae.

  17. OH radio lines in comets - a review

    International Nuclear Information System (INIS)

    Gerard, E.

    1987-01-01

    A review of OH cometary radioastronomy from the excitation of the molecule to the detailed analysis of the line profile is presented. It is suggested that the inversion models of Despois et al. (1981) and Schleicher (1983) may be improved by taking the production rates from recent UV data (when the inversion modulus is small) once the radio vs UV discrepancies are better understood. OH radiation transfer through the coma is considered. The unresolved total integrated flux density of the OH coma can be determined by carefully mapping the OH coma using a point source calibrator. The SYMCOMET method for improving the SNR of existing profiles (in order to achieve early detections) has the advantage of suppressing the antisymmetric part of the baseline ripples or instrumental profiles. 24 references

  18. Development of radio acoustic sounding method in Kharkov National University of Radio Electronics

    International Nuclear Information System (INIS)

    Proshkin, Y G; Kartashov, V M; Babkin, S I

    2008-01-01

    The analysis of the role of Kharkov National University of Radio Electronics in developing the atmosphere radio acoustic sounding (RAS) method within the period from 1968 to 2008 was carried out. As a part of the investigation program six experimental models of the sounding radio equipment were developed and manufactured. The atmosphere sounding methods were developed for measuring the base meteorological values. For the first time in the world practice, relevant comparative measurements of air temperature, wind velocity and direction were performed on a short base (about 150 m) using the centimetre RAS equipment and standard sensors of a high (300 m) meteorological mast. The RAS equipment was used for the purpose of meteorological support to investigations in the field of the atmosphere physics and applied problems. All instrumental, atmosphere and social factors, affecting operation the RAS systems, were generalized. It is shown that compact and mobile systems for remote monitoring of the atmospheric boundary layer with possible prompt obtaining of relevant information about base meteorological values in large volumes can be based on the RAS equipment

  19. Interweave Cognitive Radio with Improper Gaussian Signaling

    KAUST Repository

    Hedhly, Wafa; Amin, Osama; Alouini, Mohamed-Slim

    2018-01-01

    Improper Gaussian signaling (IGS) has proven its ability in improving the performance of underlay and overlay cognitive radio paradigms. In this paper, the interweave cognitive radio paradigm is studied when the cognitive user employs IGS

  20. A search for radio pulsars and fast transients in M31 using the Westerbork Synthesis Radio Telescope

    NARCIS (Netherlands)

    Rubio-Herrera, E.; Stappers, B.W.; Hessels, J.W.T.; Braun, R.

    2013-01-01

    We present the results of the most sensitive and comprehensive survey yet undertaken for radio pulsars and fast transients in the Andromeda galaxy (M31) and its satellites, using the Westerbork Synthesis Radio Telescope (WSRT) at a central frequency of 328 MHz. We used the WSRT in a special

  1. An adaptive software defined radio design based on a standard space telecommunication radio system API

    Science.gov (United States)

    Xiong, Wenhao; Tian, Xin; Chen, Genshe; Pham, Khanh; Blasch, Erik

    2017-05-01

    Software defined radio (SDR) has become a popular tool for the implementation and testing for communications performance. The advantage of the SDR approach includes: a re-configurable design, adaptive response to changing conditions, efficient development, and highly versatile implementation. In order to understand the benefits of SDR, the space telecommunication radio system (STRS) was proposed by NASA Glenn research center (GRC) along with the standard application program interface (API) structure. Each component of the system uses a well-defined API to communicate with other components. The benefit of standard API is to relax the platform limitation of each component for addition options. For example, the waveform generating process can support a field programmable gate array (FPGA), personal computer (PC), or an embedded system. As long as the API defines the requirements, the generated waveform selection will work with the complete system. In this paper, we demonstrate the design and development of adaptive SDR following the STRS and standard API protocol. We introduce step by step the SDR testbed system including the controlling graphic user interface (GUI), database, GNU radio hardware control, and universal software radio peripheral (USRP) tranceiving front end. In addition, a performance evaluation in shown on the effectiveness of the SDR approach for space telecommunication.

  2. Particle reacceleration and apparent radio source structure

    International Nuclear Information System (INIS)

    Eilek, J.A.

    1982-01-01

    The radio galaxy model which uses magnetohydrodynamic turbulence generated by surface instabilities to reaccelerate the radiating electrons has striking consequences for apparent source structure. Strong wave damping in the plasma results in a narrow turbulent edge. Particles accelerated in this edge must diffuse across field lines into the radio source; this predicts strong limb brightening in some cases. The structure of this edge and diffusion into the source are described. The relevance of this model to jets, radio tails, and standard double sources is discussed

  3. 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

  4. Remote Sensing of the Heliospheric Solar Wind using Radio ...

    Indian Academy of Sciences (India)

    tribpo

    Astr. (2000) 21, 439–444. Remote Sensing of the Heliospheric Solar Wind using Radio. Astronomy Methods and Numerical Simulations. S. Ananthakrishnan, National Center for Radio Astrophysics, Tata Institute of. Fundamental Research, Pune, India. Abstract. The ground-based radio astronomy method of interplanetary.

  5. Fossil shell emission in dying radio loud AGNs

    Science.gov (United States)

    Kino, M.; Ito, H.; Kawakatu, N.; Orienti, M.; Nagai, H.; Wajima, K.; Itoh, R.

    2016-02-01

    We investigate shell emission associated with dying radio loud AGNs. First, based on our recent work by Ito et al. (2015), we describe the dynamical and spectral evolution of shells after stopping the jet energy injection. We find that the shell emission overwhelms that of the radio lobes soon after stopping the jet energy injection because fresh electrons are continuously supplied into the shell via the forward shock, while the radio lobes rapidly fade out without jet energy injection. We find that such fossil shells can be a new class of target sources for SKA telescope. Next, we apply the model to the nearby radio source 3C84. Then, we find that the fossil shell emission in 3C84 is less luminous in the radio band while it is bright in the TeV γ-ray band and can be detectable by CTA. Data from STELLA

  6. The Radio Synchrotron Background: Conference Summary and Report

    Science.gov (United States)

    Singal, J.; Haider, J.; Ajello, M.; Ballantyne, D. R.; Bunn, E.; Condon, J.; Dowell, J.; Fixsen, D.; Fornengo, N.; Harms, B.; Holder, G.; Jones, E.; Kellermann, K.; Kogut, A.; Linden, T.; Monsalve, R.; Mertsch, P.; Murphy, E.; Orlando, E.; Regis, M.; Scott, D.; Vernstrom, T.; Xu, L.

    2018-03-01

    We summarize the radio synchrotron background workshop that took place 2017 July 19–21 at the University of Richmond. This first scientific meeting dedicated to the topic was convened because current measurements of the diffuse radio monopole reveal a surface brightness that is several times higher than can be straightforwardly explained by known Galactic and extragalactic sources and processes, rendering it by far the least well understood photon background at present. It was the conclusion of a majority of the participants that the radio monopole level is at or near that reported by the ARCADE 2 experiment and inferred from several absolutely calibrated zero-level lower frequency radio measurements, and unanimously agreed that the production of this level of surface brightness, if confirmed, represents a major outstanding question in astrophysics. The workshop reached a consensus on the next priorities for investigations of the radio synchrotron background.

  7. No evidence for radio-quiet BL Lacertae objects

    International Nuclear Information System (INIS)

    Stocke, J.T.; Morris, S.L.; Gioia, I.; Maccacaro, T.; Schild, R.E.

    1990-01-01

    Using a large, flux-limited sample of faint X-ray sources, a search has been conducted for radio-quiet BL Lacertae objects. None has been found. Thirty-two X-ray-selected BL Lac objects and BL Lac candidates have been found within the sources of the Einstein Medium Sensitivity Survey (EMSS). Thirty-one of these have been observed with the VLA and all have been detected at 5 GHz. While the optical magnitudes of the EMSS BL Lac objects range from 17 to 20.8, their radio-to-optical spectral indices occupy a very small range. The very bright X-ray-selected BL Lac objects like PKS 2155-304 and Markarian 501 have similar range values. Therefore, unlike the clear dichotomy between radio-loud quasars and radio-quiet QSOs, there is no evidence for two populations of Lacertids distinguished by radio loudness. 43 refs

  8. Cognitive Radio for Smart Grid with Security Considerations

    Directory of Open Access Journals (Sweden)

    Khaled Shuaib

    2016-04-01

    Full Text Available In this paper, we investigate how Cognitive Radio as a means of communication can be utilized to serve a smart grid deployment end to end, from a home area network to power generation. We show how Cognitive Radio can be mapped to integrate the possible different communication networks within a smart grid large scale deployment. In addition, various applications in smart grid are defined and discussed showing how Cognitive Radio can be used to fulfill their communication requirements. Moreover, information security issues pertained to the use of Cognitive Radio in a smart grid environment at different levels and layers are discussed and mitigation techniques are suggested. Finally, the well-known Role-Based Access Control (RBAC is integrated with the Cognitive Radio part of a smart grid communication network to protect against unauthorized access to customer’s data and to the network at large.

  9. Advertising Radio Discourse – Lexical Analysis

    Directory of Open Access Journals (Sweden)

    Dumitrascu Elena

    2017-01-01

    Full Text Available Radio advertising, although it seems to be the "poor relative" on the advertising market, is avery interesting topic of study, because it uses language to a very large extent. In a relatively shorttime, a maximum of information is transmitted that causes emotions and raises the interest of asmany people as possible for a product or brand, all wrapped up in a coherent text of 60 to 100words . In radio advertising, the text is the one that has priority, being the star because themessage is based on the text. For this reason, radio discourse may be a research object of interestto linguists, and this has led us to pay close attention to it.

  10. Using the SLAC VHF and UHF radio systems

    International Nuclear Information System (INIS)

    Struven, W.

    1987-02-01

    The use of the SLAC VHF and UHF Radio Systems and the Tunnel Antenna Systems as they are presently configured is described. The original radio system was built in 1966 and has grown in scope over the years. The Tunnel Antenna Systems were developed for, and first installed in, the PEP ring, and later added to other tunnels and redesigned to cover the UHF range, as well as VHF. The UHF radio system was designed and built for SLC use, and was first used in the SLC Arcs. The three radio systems will be described and the capabilities of each system will be defined

  11. The Evolution of the Stellar Hosts of Radio Galaxies

    International Nuclear Information System (INIS)

    Lacy, Mark; Bunker, Andrew J.; Ridgway, Susan E.

    2000-01-01

    We present new near-infrared images of z>0.8 radio galaxies from the flux-limited 7C-iii sample of radio sources for which we have recently obtained almost complete spectroscopic redshifts. The 7C objects have radio luminosities ≅20 times fainter than 3C radio galaxies at a given redshift. The absolute magnitudes of the underlying host galaxies and their scale sizes are only weakly dependent on radio luminosity. Radio galaxy hosts at z∼2 are significantly brighter than the hosts of radio-quiet quasars at similar redshifts and the recent model AGN hosts of Kauffmann and Haehnelt. There is no evidence for strong evolution in scale size, which shows a large scatter at all redshifts. The hosts brighten significantly with redshift, consistent with the passive evolution of a stellar population that formed at z(greater-or-similar sign)3. This scenario is consistent with studies of host galaxy morphology and submillimeter continuum emission, both of which show strong evolution at z(greater-or-similar sign)2.5. The lack of a strong ''redshift cutoff'' in the radio luminosity function to z>4 suggests that the formation epoch of the radio galaxy host population lasts (greater-or-similar sign)1 Gyr, from z(greater-or-similar sign)5 to z∼3. We suggest these facts are best explained by models in which the most massive galaxies and their associated AGN form early because of high baryon densities in the centers of their dark matter haloes. (c) 2000 The American Astronomical Society

  12. KILOPARSEC-SCALE RADIO STRUCTURES IN NARROW-LINE SEYFERT 1 GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Doi, Akihiro; Kino, Motoki [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuou-ku, Sagamihara, Kanagawa 252-5210 (Japan); Nagira, Hiroshi [Graduate School of Science and Engineering, Yamaguchi University, 1677-1 Yoshida, Yamaguchi, Yamaguchi 753-8512 (Japan); Kawakatu, Nozomu [Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8571 (Japan); Nagai, Hiroshi [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Asada, Keiichi, E-mail: akihiro.doi@vsop.isas.jaxa.jp [Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 10617, Taiwan (China)

    2012-11-20

    We report the finding of kiloparsec (kpc)-scale radio structures in three radio-loud narrow-line Seyfert 1 (NLS1) galaxies from the Faint Images of the Radio Sky at Twenty-centimeters of the Very Large Array, which increases the number of known radio-loud NLS1s with kpc-scale structures to six, including two {gamma}-ray-emitting NLS1s (PMN J0948+0022 and 1H 0323+342) detected by the Fermi Gamma-ray Space Telescope. The detection rate of extended radio emissions in NLS1s is lower than that in broad-line active galactic nuclei (AGNs) with a statistical significance. We found both core-dominated (blazar-like) and lobe-dominated (radio-galaxy-like) radio structures in these six NLS1s, which can be understood in the framework of the unified scheme of radio-loud AGNs that considers radio galaxies as non-beamed parent populations of blazars. Five of the six NLS1s have (1) extended radio luminosities suggesting jet kinetic powers of {approx}> 10{sup 44} erg s{sup -1}, which is sufficient to make jets escape from hosts' dense environments; (2) black holes of {approx}> 10{sup 7} M {sub Sun }, which can generate the necessary jet powers from near-Eddington mass accretion; and (3) two-sided radio structures at kpc scales, requiring expansion rates of {approx}0.01c-0.3c and kinematic ages of {approx}> 10{sup 7} years. On the other hand, most typical NLS1s would be driven by black holes of {approx}< 10{sup 7} M {sub Sun} in a limited lifetime of {approx}10{sup 7} years. Hence, the kpc-scale radio structures may originate in a small window of opportunity during the final stage of the NLS1 phase just before growing into broad-line AGNs.

  13. 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.

  14. Radio on the Other Side of Time

    Directory of Open Access Journals (Sweden)

    Alicia TAPIA LÓPEZ

    2016-06-01

    Full Text Available On October 30, 1938, Orson Welles aired the radio drama The War of the Worlds on the CBS Radio network, adapting the science-fiction novel by the British writer H. G. Wells. During the broadcast, listeners became stricken with panic, believing that the Earth was actually being invaded by giant snake-like Martians launching rays of fire down on humans. Welles was a groundbreaking figure whose trickery exploited the technological novelty of the radio to its fullest, adapting classic texts in ways that exploited the opportunities afforded by this new medium. Over the years, this radio classic has been adapted a number of times, though none has seized on the technological advances of our times. Drawing on the most salient innovations seen in Internet radio, this article creates an imaginary scenario that replicates Orson Welles’s work in the present day, when the Internet has become a channel for broadcasting and hyperlinks have brought different media together. The text is an exploration of the other side of time, where transmedia storytelling facilitates the exchange of stories among consumers, and broadcast programming is no longer linear.

  15. Innovations to enrich science communication through radio

    Directory of Open Access Journals (Sweden)

    Thakar Bhaumik

    2004-12-01

    Full Text Available The Radio is an instrument of communication that has percolated to all the strata of the diverse Indian society. Its position has been consolidated through history as a regular companion and a source of information and entertainment. Its affordability, accessibility and non-reliance on costly resources have ensured its presence in almost all the households. It has become indispensable from kitchens, family rooms and even workspaces. It is one of the few or rather the only medium of communication after the print media wherein information dissemination still is primary and entertainment a secondary requirement, especially the rural areas. The role of radio in rural India is one that demands prominence and hence has been used as a primary resource for various projects on science communication. A majority of the science radio serial listeners are from the rural areas. The radio therefore is an ideal medium for reaching out to the masses. The radio even with its popularity and huge following is lacking in certain aspects that make science communication complete. Manthan Educational Programme Society developed concepts to make these efforts more effective by ensuring higher involvement and interest in these programs.

  16. Radio emission from embryonic superluminous supernova remnants

    Science.gov (United States)

    Omand, Conor M. B.; Kashiyama, Kazumi; Murase, Kohta

    2018-02-01

    It has been widely argued that Type-I superluminous supernovae (SLSNe-I) are driven by powerful central engines with a long-lasting energy injection after the core-collapse of massive progenitors. One of the popular hypotheses is that the hidden engines are fast-rotating pulsars with a magnetic field of B ˜ 1013-1015 G. Murase, Kashiyama & Mészáros proposed that quasi-steady radio/submm emission from non-thermal electron-positron pairs in nascent pulsar wind nebulae can be used as a relevant counterpart of such pulsar-driven supernovae (SNe). In this work, focusing on the nascent SLSN-I remnants, we examine constraints that can be placed by radio emission. We show that the Atacama Large Millimeter/submillimetre Array can detect the radio nebula from SNe at DL ˜ 1 Gpc in a few years after the explosion, while the Jansky Very Large Array can also detect the counterpart in a few decades. The proposed radio follow-up observation could solve the parameter degeneracy in the pulsar-driven SN model for optical/UV light curves, and could also give us clues to young neutron star scenarios for SLSNe-I and fast radio bursts.

  17. Remnant radio-loud AGN in the Herschel-ATLAS field

    Science.gov (United States)

    Mahatma, V. H.; Hardcastle, M. J.; Williams, W. L.; Brienza, M.; Brüggen, M.; Croston, J. H.; Gurkan, G.; Harwood, J. J.; Kunert-Bajraszewska, M.; Morganti, R.; Röttgering, H. J. A.; Shimwell, T. W.; Tasse, C.

    2018-04-01

    Only a small fraction of observed active galactic nuclei (AGN) display large-scale radio emission associated with jets, yet these radio-loud AGN have become increasingly important in models of galaxy evolution. In determining the dynamics and energetics of the radio sources over cosmic time, a key question concerns what happens when their jets switch off. The resulting `remnant' radio-loud AGN have been surprisingly evasive in past radio surveys, and therefore statistical information on the population of radio-loud AGN in their dying phase is limited. In this paper, with the recent developments of Low-Frequency Array (LOFAR) and the Very Large Array, we are able to provide a systematically selected sample of remnant radio-loud AGN in the Herschel-ATLAS field. Using a simple core-detection method, we constrain the upper limit on the fraction of remnants in our radio-loud AGN sample to 9 per cent, implying that the extended lobe emission fades rapidly once the core/jets turn off. We also find that our remnant sample has a wide range of spectral indices (-1.5≤slant α ^{1400}_{150}≤slant -0.5), confirming that the lobes of some remnants may possess flat spectra at low frequencies just as active sources do. We suggest that, even with the unprecedented sensitivity of LOFAR, our sample may still only contain the youngest of the remnant population.

  18. Immunochemical studies of Lolium perenne (rye grass) pollen allergens, Lol p I, II, and III.

    Science.gov (United States)

    Ansari, A A; Kihara, T K; Marsh, D G

    1987-12-15

    It was reported earlier that human immune responses to three perennial rye grass (Lolium perenne) pollen allergens, Lol p I, II, and III, are associated with histocompatibility leukocyte antigen (HLA)-DR3. Rye-allergic people are often concordantly sensitive to all three of these allergens. Since earlier studies suggested that these antigens are non-cross-reactive, their immunologic relatedness by double antibody radioimmunoassay (DARIA) was studied in order to understand further the immunochemical basis for the concordant recognition of the three allergens. Direct binding DARIA studies were performed with human sera from 189 allergic subjects. Inhibition DARIA studies were carried out with 17 human sera from grass-allergic patients who were on grass immunotherapy, one goat anti-serum, and six rabbit antisera. None of the sera detected any significant degree of two-way cross-reactivity between Lol p I and II, or between Lol p I and III. However, the degree of two-way cross-reactivity between Lol p II and III exhibited by individual human and animal antisera varied between undetectable and 100%. In general, the degree of cross-reactivity between Lol p II and III was higher among human sera than among animal sera. Taken together with earlier findings that antibody responses to Lol p I, II and III are associated with HLA-HDR3, and that most Lol p II and III responders are also Lol p I responders, but not vice versa, our present results suggest the following: the HLA-DR3-encoded Ia molecule recognizes a similar immunodominant Ia recognition site (agretope) shared between Lol p I and Lol p II and/or III; in addition, Lol p I appears to contain unique Ia recognition site(s) not present in Lol p II and III. However, further epitope analyses are required to investigate these possibilities.

  19. Radio Access Sharing Strategies for Multiple Operators in Cellular Networks

    DEFF Research Database (Denmark)

    Popovska Avramova, Andrijana; Iversen, Villy Bæk

    2015-01-01

    deployments (required for coverage enhancement), increased base station utilization, and reduced overall power consumption. Today, network sharing in the radio access part is passive and limited to cell sites. With the introduction of Cloud Radio Access Network and Software Defined Networking adoption...... to the radio access network, the possibility for sharing baseband processing and radio spectrum becomes an important aspect of network sharing. This paper investigates strategies for active sharing of radio access among multiple operators, and analyses the individual benefits depending on the sharing degree...

  20. Comparison of SDR presumed by AAMI and the radio-resistance distribution of the microbiological populations exist on the Turkish made single use syringes

    International Nuclear Information System (INIS)

    Konac, T.; Siyakus, G.; Basguel, M.; Uenal, Z.

    2001-01-01

    The concept of radiation sterilization of medical devices was introduced in Turkey 10 years ago through the irradiation facilities in Ankara and Istanbul. It has been preferred by international community due to technological advantages,such as freedom from chemical residues, safer sterility assurance, etc.. This technology is regulated by ISO 11137 (1), EN 552 (2) standards and their references. The scope of this study was to compare the radio-resistance distribution of the microbial population on the Turkish single use syringes and SDR