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1
Sovers, O. J., C. D. Edwards, C. S. Jacobs, G. E. Lanyi, and R. N. Treuhaft. "The JPL 1986–3 Extragalactic Reference Frame." Symposium - International Astronomical Union 133 (1988): 461–64. http://dx.doi.org/10.1017/s0074180900140021.
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Intercontinental dual-frequency radio interferometric measurements were carried out during 1978 to 1985 between NASA's Deep Space Network stations in California, Spain, and Australia. Analysis of 6800 pairs of delay and delay rate observations made during 51 sessions produced a catalog of positions of 106 extragalactic radio sources, fairly uniformly distributed over the celestial sphere between −45° and +85° declination. Almost all of the resulting source positions have formal uncertainties between 0.5 and 3 milliarcseconds, with their distributions peaking somewhat below 1 mas. Root-mean-square uncertainties are 2.1 and 2.0 mas for RA and declination, respectively. Evidence is found for a long-term drift of the Earth's rotation axis in inertial space, relative to the 1984 IAU precession and nutation models. Tests for time variability of positions of 32 frequently observed sources place limits at the 1 mas/yr level. Comparisons with independently determined source catalogs of comparable quality show differences of positions of common sources that amount to a few mas, and may indicate the level of systematic errors in VLBI source position measurements.
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Blanco, Juan Carlos, Yolanda Cortés, and Emilio Virgós. "Wolf response to two kinds of barriers in an agricultural habitat in Spain." Canadian Journal of Zoology 83, no. 2 (February 1, 2005): 312–23. http://dx.doi.org/10.1139/z05-016.
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We examined the effect of two kinds of barriers on an expanding gray wolf, Canis lupus L., 1758, population in an agricultural habitat in north-central Spain. The barriers were (i) a four-lane fenced highway along a flat area without wildlife-crossing facilities, and (ii) the River Duero Artery (RDA), comprising the river itself (50–100 m wide) and several small infrastructures along it. From March 1997 to October 2001, all 4 radio-collared wolves living <15 km from the highway (1 adult territorial male, 1 territorial breeder female, 1 dispersing male, and 1 female in 3 periods of her life (territorial immature, disperser, and territorial breeder) crossed it on between 4% and 33% of 45–163 monitoring days via vehicle bridges. Moreover, 4 more highways that we monitored in areas without radio-collared wolves have not delayed expansion of the increasing wolf population, suggesting that these highways are not an important barrier for wolves in our study area. In contrast, only 3 of 8 wolves radio-collared <5 km from the RDA were detected crossing it, and 2 of those 3 started to cross it only after severe habitat disturbance; in addition, the RDA seems to have delayed wolf expansion for some 15 years, which suggests that it is a semipermeable barrier for wolves. We discuss the likely consequences of the RDA on the recovery of the Iberian wolf population.
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Despois, D., T. Forveille, J. Schraml, D. Bockelée-Morvan, J. Crovisier, and E. Gérard. "Observations of the HCN Molecule in Comet Halley." Symposium - International Astronomical Union 120 (1987): 429–30. http://dx.doi.org/10.1017/s0074180900154439.
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We report here the detection of the J 1-0 rotational line at 88.6 GHz of hydrogen cyanide in comet Halley. Six observational runs were made in the Nov. 19-Dec. 3 1985 period with the IRAM 30-m millimetre radio telescope at Pico Veleta (Spain), when the comet was at rh ~ 1.56 AU from the Sun and Δ ~ 0.63 AU from the Earth.
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Fajula, Anna, Mariluz Barbeito, Estrella Barrio, Ana Maria Enrique, and Juan José Perona. "Feminist Stereotypes and Women’s Roles in Spanish Radio Ads." Media and Communication 9, no. 2 (March 23, 2021): 39–51. http://dx.doi.org/10.17645/mac.v9i2.3762.
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This article takes a quantitative approach to Spanish radio advertising and the stereotypes and female roles that it broadcasts in a medium that has traditionally had high female audience rates in our country. From content analysis of 679 radio ads extracted from the 3 main general Spanish radio stations and collected 10 years apart, the study attempts to show the evolution (or regression) of how radio advertising portrays women. The radio in Spain has always been a medium anchored in the real world that has also provided some degree of space to broadcast social movement. #MeToo, as a phenomenon promoting female empowerment, was no exception. Therefore, this longitudinal study aims to demonstrate whether the social movements that led to increased female activism have been reflected in a change of roles and stereotypes projected by radio advertising messages. The work presented here looks at the concept of role from a dual perspective: firstly, it focuses on the role played by female voices in radio advertising items. Secondly, it works on the concept of role by assimilating it into the female image projected in radio advertising items. The results obtained between the two samples are remarkably similar, demonstrating a clear tendency to polarise the female image and confirming that women are still being portrayed in significantly traditional roles.
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Vázquez, R., L. F. Miranda, J. M. Torrelles, C. Eiroa, and J. A. López. "Radio continuum and long-slit optical spectroscopy of the Planetary Nebulae Cn 3-1 and M 3-27." Symposium - International Astronomical Union 180 (1997): 283. http://dx.doi.org/10.1017/s0074180900131006.
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Long-slit optical spectroscopy and VLA-B radio continuum (λ = 3.6 cm) observations toward the compact planetary nebulae Cn 3-1 and M 3-27 are presented. Optical spectra were taken at different position angles (PAs) with the 2.2 m telescope at Calar Alto (Spain), covering the range from 6549 to 6751 Å. The radio and optical data show that the ionized shell of Cn 3-1 is an ellipsoid (size ≃ 6″ × 5″, PA ≃ 72°) containing a bright ring-like equatorial zone (size ≃ 2″.6, expansion velocity ≃ 14 km s–1) and two bright point-symmetric arcs, extending from the equator towards the polar regions of the ellipsoid (Fig. 1). These arcs seem to be filamentary structures embedded in the ellipsoid. An ionized stellar wind has been detected through faint extended wings in the Hα (≃ 660 km s–1) and [N II] (≃ 460 km s–1) emission lines. M 3-27 is unresolved at 3.6 cm (size ≤ 0″6). The detected [N II] and [S II] emission lines arise in a compact (≤ 1″4) probably non-spherical region which is identified with the ionized shell of M 3-27. The Hα emission from M 3-27 is dominated by strong emission from an ionized stellar wind and exhibits a Type III P Cygni profile with very extended wings (≃ 3000 km s–1). The estimated kinematic age and ionized mass of Cn 3-1 (≃ 1300 yr, 4 × 10–2 M⊙) and M 3-27 (≤ 530 yr, ≃ 3 × 10–4 M⊙) indicate that both objects are young planetary nebulae. Extended halos (size ≃ 36″ in Cn 3-1, ≃ 24″ in M 3-27) have been spectroscopically detected in both objects. An analysis of the kinematic and emission properties shows that both halos are reflection nebulosities and suggests that the distribution of neutral material in them probably is largely isotropic. The results suggest that the halos correspond to isotropic mass ejections occurred in the last ≃ 2 × 104 yr of the AGB phase of the Cn 3-1 and M 3-27 progenitors.
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Gómez Martín, J. C., J. Blahins, U. Gross, T. Ingham, A. Goddard, A. S. Mahajan, A. Ubelis, and A. Saiz-Lopez. "In situ detection of atomic and molecular iodine using resonance and off-resonance fluorescence by lamp excitation: ROFLEX." Atmospheric Measurement Techniques Discussions 3, no. 4 (August 25, 2010): 3803–49. http://dx.doi.org/10.5194/amtd-3-3803-2010.
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Abstract. We demonstrate a new instrument for in situ detection of atmospheric iodine atoms and molecules based on atomic and molecular resonance and off-resonance ultraviolet fluorescence excited by lamp emission. The instrument combines the robustness, light weight, low power consumption and efficient excitation of radio-frequency discharge light sources with the high sensitivity of the photon counting technique. Calibration of I2 fluorescence is achieved via quantitative detection of the molecule by incoherent broad band cavity-enhanced absorption spectroscopy. Atomic iodine fluorescence signal is calibrated by controlled broad band photolysis of known I2 concentrations in the visible spectral range at atmospheric pressure. The instrument has been optimised in laboratory experiments to reach detection limits of 1.2 pptv for I atoms and 20 pptv for I2, for S/N=1 and 10 min of integration time. The ROFLEX system has been deployed in a field campaign in Northern Spain, representing the first concurrent observation of ambient mixing ratios of iodine atoms and molecules in the 1–350 pptv range.
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Dietrich, M., P. T. O’Brien, and K. M. Leighly. "First Results of Optical Monitoring of 3C 390.3." International Astronomical Union Colloquium 159 (1997): 163–64. http://dx.doi.org/10.1017/s0252921100039889.
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In late autumn 1994, the International AGN Watch started a multiwavelength monitoring campaign on 3C 390.3, the first radio-loud AGN to be selected for high temporal-resolution monitoring from the radio domain to X-ray energies. This AGN is is of particular interest since significant variations have been observed on both short and long time scales in both the line fluxes and line profiles (Barr et al. 1980, Veilleux & Zheng 1991).In the optical, spectroscopic data and broad-band flux measurements in B, V, R, and I were obtained. The brightness of 3C 390.3 was calculated relative to the stars in the field. The R magnitudes are based on observations recorded at Calar Alto, Spain, in 1994 December. Generally, AGN spectra are intercalibrated using narrow forbidden emission lines since these lines can be taken as constant on time scales of decades (Peterson 1993). Since the [O III] λλ4959, 5007 flux is variable on time scales of several months (Zheng et al. 1995), these lines were studied in detail. We found that they were constant within ~2% during 1995 (Dietrich et al. 1996). The spectra were therefore intercalibrated by using the narrow forbidden emission lines. 3C 390.3 was also observed with IUE for 14 months (O’Brien et al. 1996) and with ROSAT for nine months in 1995 (Leighly et al. 1996). Radio data were also obtained during a 3-month MERLIN campaign.
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Pović, Mirjana. "Development in astronomy in Ethiopia and East-Africa through nuclear activity in galaxies." Proceedings of the International Astronomical Union 15, S356 (October 2019): 3–8. http://dx.doi.org/10.1017/s174392132000246x.
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AbstractIn this paper we summarise the research that is currently going on in Ethiopia and East-Africa in extragalactic astronomy and physics of active galaxies and active galactic nuclei (AGN). The study is focused on some of the still open questions such as: what are the stellar ages and populations of ultra hard X-ray detected AGN and connection between AGN and their host galaxies?, what are the properties of AGN in galaxy clusters and the role that environment has in triggering nuclear activity?, what are the morphological properties of AGN and how precisely we can deal with morphological classification of active galaxies?, what are the properties of galaxies in the green valley and the role of AGN in galaxy evolution?, and what are the properties of radio-loud and radio-quiet quasars (QSO) and dichotomy between the two?. Each of these questions has been developed under one specific project that will be briefly introduced. These projects involve 6 PhD and 3 MSc students and collaborations between Ethiopia, Rwanda, South Africa, Uganda, Tanzania, Spain, Italy, and Chile. With all projects we aim: first, to contribute to our general knowledge about AGN, and second, to contribute to the development in astronomy and science in Ethiopia and East-Africa.
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Llasat, M. C., T. Rigo, M. Ceperuelo, and A. Barrera. "Estimation of convective precipitation: the meteorological radar versus an automatic rain gauge network." Advances in Geosciences 2 (May 2, 2005): 103–9. http://dx.doi.org/10.5194/adgeo-2-103-2005.
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Abstract. The estimation of convective precipitation and its contribution to total precipitation is an important issue both in hydrometeorology and radio links. The greatest part of this kind of precipitation is related with high intensity values that can produce floods and/or damage and disturb radio propagation. This contribution proposes two approaches for the estimation of convective precipitation, using the β parameter that is related with the greater or lesser convective character of the precipitation event, and its time and space distribution throughout the entire series of the samples. The first approach was applied to 126 rain gauges of the Automatic System of Hydrologic Information of the Internal Basins of Catalonia (NE Spain). Data are series of 5-min rain rate, for the period 1996-2002, and a long series of 1-min rain rate starting in 1927. Rainfall events were classified according to this parameter. The second approach involved using information obtained by the meteorological radar located near Barcelona. A modified version of the SCIT method for the 3-D analysis and a combination of different methods for the 2-D analysis were applied. Convective rainfall charts and β charts were reported. Results obtained by the rain gauge network and by the radar were compared. The application of the β parameter to improve the rainfall regionalisation was demonstrated.
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Querol, Xavier, Andrés Alastuey, Gotzon Gangoiti, Noemí Perez, Hong K. Lee, Heeram R. Eun, Yonghee Park, et al. "Phenomenology of summer ozone episodes over the Madrid Metropolitan Area, central Spain." Atmospheric Chemistry and Physics 18, no. 9 (May 8, 2018): 6511–33. http://dx.doi.org/10.5194/acp-18-6511-2018.
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Abstract. Various studies have reported that the photochemical nucleation of new ultrafine particles (UFPs) in urban environments within high insolation regions occurs simultaneously with high ground ozone (O3) levels. In this work, we evaluate the atmospheric dynamics leading to summer O3 episodes in the Madrid air basin (central Iberia) by means of measuring a 3-D distribution of concentrations for both pollutants. To this end, we obtained vertical profiles (up to 1200 m above ground level) using tethered balloons and miniaturised instrumentation at a suburban site located to the SW of the Madrid Metropolitan Area (MMA), the Majadahonda site (MJDH), in July 2016. Simultaneously, measurements of an extensive number of air quality and meteorological parameters were carried out at three supersites across the MMA. Furthermore, data from O3 soundings and daily radio soundings were also used to interpret atmospheric dynamics. The results demonstrate the concatenation of venting and accumulation episodes, with relative lows (venting) and peaks (accumulation) in O3 surface levels. Regardless of the episode type, the fumigation of high-altitude O3 (arising from a variety of origins) contributes the major proportion of surface O3 concentrations. Accumulation episodes are characterised by a relatively thinner planetary boundary layer (< 1500 m at midday, lower in altitude than the orographic features), light synoptic winds, and the development of mountain breezes along the slopes of the Guadarrama Mountain Range (located W and NW of the MMA, with a maximum elevation of > 2400 m a.s.l.). This orographic–meteorological setting causes the vertical recirculation of air masses and enrichment of O3 in the lower tropospheric layers. When the highly polluted urban plume from Madrid is affected by these dynamics, the highest Ox (O3+ NO2) concentrations are recorded in the MMA. Vertical O3 profiles during venting episodes, with strong synoptic winds and a deepening of the planetary boundary layer reaching > 2000 m a.s.l., were characterised by an upward gradient in O3 levels, whereas a reverse situation with O3 concentration maxima at lower levels was found during the accumulation episodes due to local and/or regional production. The two contributions to O3 surface levels (fumigation from high-altitude strata, a high O3 background, and/or regional production) require very different approaches for policy actions. In contrast to O3 vertical top-down transfer, UFPs are formed in the planetary boundary layer (PBL) and are transferred upwards progressively with the increase in PBL growth.
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Ferrero, M. A., C. Pérez, A. Iscar, B. Medrano, J. J. Rodriguez, and H. Alsusi. "Estudio a largo plazo (más de 10 años de evolución), de las complicaciones de las artroplastias trapecio-metacarpianas de tipo ARPE®." Revista Iberoamericana de Cirugía de la Mano 42, no. 02 (November 2014): 107–18. http://dx.doi.org/10.1055/s-0037-1607105.
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Objetivo: La artrosis trapecio-metacarpiana es una patología incapacitante, que produce dolor, disminución de la fuerza, pérdida de destreza en la pinza y limitación de la movilidad del pulgar. Cuando fracasa el tratamiento médico se pueden realizar diferentes técnicas quirúrgicas. Las prótesis totales de la articulación representan una de ellas. Desde mayo de 1999 hasta abril de 2004 se realizaron, de forma consecutiva, un total de 116 prótesis totales de la articulación trapecio-metacarpiana en 103 pacientes que padecían artrosis, utilizando la prótesis no cementada y no constreñida tipo ARPE® (Biomet Spain Orthopaedics SL, Valencia). Se presentan en este estudio los resultados de la revisión clínica, funcional y radiológica de los pacientes revisados durante 10 años de evolución.Material y Método: Los análisis de supervivencia fueron realizados mediante el método de Kaplan-Meier. De los 103 pacientes, 6 fueron excluidos y 97 pacientes, con 109 prótesis acabaron el estudio.Resultados: En la revisión de los 10 años de evolución, 102 (93,6%) eran prótesis funcionales y 7 (6,4%) prótesis eran consideradas prótesis fallidas (3 retiradas por aflojamiento, 3 luxaciones y 1 subluxación y dolor). La probabilidad de supervivencia de Kaplan–Meier fue de 94.1% [CI95% (90.4%,98.8%)]. Radiográficamente, 88 (86,3%) de las prótesis consideradas funcionales no mostraron evidencia de alteraciones del implante y 14 (13,7%) mostraron cambios radio gráficos que eran compatibles con la funcionalidad del implante. Se presenta en detalle el estudio de las complicaciones que han existido, con las posibles soluciones en las cirugías de revisión.Conclusión: La prótesis total de ARPE® ofrece una alternativa de tratamiento segura y fiable en pacientes con artrosis trapecio-metacarpiana grado III y algunos de grado IV con buen capital óseo, sobre todo, en el trapecio. La mayoría de las complicaciones aparecen por defectos de indicación o por defectos de la técnica quirúrgica y se pueden resolver con recambio protésico o con trapecectomía dependiendo de las circunstancias del implante y del paciente.
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Rickards, Guy. "New Releases of music by Women Composers." Tempo 59, no. 231 (January 2005): 74–80. http://dx.doi.org/10.1017/s0040298205260072.
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CECILIE ØRE: A. – a shadow opera. Joachim Calmeyer, Anneke von der Lippe, Tilman Hartenstein, Henrik Inadomi, Lakis Kanzakis, Rob Waring (voices). Aurora ACD 5034.BETH ANDERSON ‘Swales and Angels’: March Swale1; Pennyroyal Swale1; New Mexico Swale2,1,3; The Angel4,1,5,6,8; January Swale1; Rosemary Swale1; Piano Concerto6,1,7,3,8. 1Rubio String Quartet, 2Andrew Bolotowsky (fl, picc), 3David Rozenblatt (perc), 4Jessica Marsten (sop), 5Joseph Kubera (vc, pno), 6André Tarantiles (hp), 7Darren Campbell (bass), c. 8Gary M. Scheider. New World 80610-2.RAGNHILD BERSTAD: Anstrøk for violin and cello1; Krets for orchestra9; Respiro for clarinet and tape2; Zeugma for ensemble3; Toreuma for string quartet4; Verto for voice, cello & percussion5,6,7; Emutatio for voice, chorus and orchestra5,8,9. 1Kyberia, 2Lars Hilde (cl), 3Affinis Ensemble, 4Arditti String Quartet, 5Berit Ogheim (voice), 6Lene Grenager (vc), 7Cathrine Nyheim (perc), 8Oslo Chamber Choir, 9Norwegian Radio Orchestra c. Christian Eggen. Aurora ACD 5021.TAILLEFERRE: Works for piano. Cristiano Ariagno (pno). Timpani 1C1074.‘Sweetly I Rejoice: Music based on Songs and Hymns from Old Icelandic Manuscripts’ by HILDIGUNNUR RÚNARSDÒTTIR, MIST THORKELSDÒTTIR, THÒRDUR MAGNÚSSON, JÒN GUDMUNDSSON, ELÍN GUNNLAUGSDÒTTIR and STEINGRÍMUR ROHLOFF. Gríma Vocal Ensemble. Marta Gudrún Halldórsdóttir (sop), EThos String Quartet. Instrumental Ensemble c. Gunnstein Òlafsson. Smekkleysa SMK31 (2-CD set).‘I Start My Journey’: Sacred music by Anon, SMÁRI ÓLASON, ELÍN GUNNLAUGSDÒTTIR, STEFÁN ÓLAFSSON, JAKOB HALLGRIMSSON, BARA GRÍMSDÒTTIR, HRÒDMAR INGI SIGURBJÖRNSSON, GUNNAR REYNÍR SVEINSSON. Kammerkor Sudurlands c. Hilmar Örn Agnarsson. Smekkleysa SMK17.‘New Zealand Women Composers’. DOROTHY KER: The Structure of Memory. JENNY McLEOD: For Seven. GILLIAN WHITEHEAD: Ahotu (O Matenga). ANNEA LOCKWOOD/Lontano: Monkey Trips (1995). Lontano c. Odaline de la Martinez. LORELT LNT116.SPAIN-DUNK: Phantasy Quartet in D minor. BEACH: String Quartet in one movement. SMYTH: String Quartet in E minor. Archaeus String Quartet. Lorelt LNT114.SAARIAHO: Du cristal…a la fumée1–3; Nymphaea4; Sept Papillons2. 1Petri Alanko (alto fl), 2Anssi Karttunen (vlc), 3Los Angeles PO c. Esa-Pekka Salonen, 4Kronos Quartet. Ondine ODE 1047-2.
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Lippmaa, E., E. Joon, I. Heinmaa, V. Miidel, A. Miller, and R. Stern. "Radio-Spectroscopic Studies of Magnetic Properties of High Temperature Superconductors." Zeitschrift für Naturforschung A 45, no. 3-4 (April 1, 1990): 401–4. http://dx.doi.org/10.1515/zna-1990-3-431.
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Abstract We have performed 17O and 63Cu NMR measurements in YBa2Cu3O7-δ (δ ≈ 0.15) oriented powder samples at CuO2 plane sites Cu(2) and 0(2, 3) in the temperature range 10-300 K. The temperature dependent Knight shift K(T) and spin lattice relaxation rate T1-1-(T) of O(2, 3) yield K2T1T = const in accordance with the presence of free carriers at plane oxygen sites. A sharp decrease of T1-1 of Cu(2) below 120 K is associated with the opening of a gap in the spectrum of antiferromagnetic spin fluctuations of localized copper 3 d9 electrons. The comparison of different temperature dependences of spin densities at the Cu and O sites shows the presence of two nearly independent spin systems. A close similarity of YBa2Cu3O7-δ a with heavy fermion superconductors is discussed.
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SHARMA, NEETIKA, and HARLEEN DAHIYA. "CHARGE RADII OF SPIN $\frac{1}{2}^+$ AND SPIN $\frac{3}{2}^+$ CHARMED BARYONS IN THE CHIRAL CONSTITUENT QUARK MODEL." International Journal of Modern Physics A 28, no. 14 (May 30, 2013): 1350052. http://dx.doi.org/10.1142/s0217751x13500528.
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The chiral constituent quark model (χCQM) with general parametrization method (GPM) has been extended to calculate the charge radii of the charmed spin [Formula: see text] and spin [Formula: see text] baryons. The implications of such a model have been investigated for the effects of symmetry breaking and GPM parameters pertaining to the one-, two- and three-quark contributions. It is found that the χCQM along with these effects is successful in giving a quantitative and qualitative description of the charge radii of charmed baryons. In particular, it is able to account for the nonzero values of charge radii for the neutral charmed baryons.
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Akamatsu, Hirofumi, Shunsuke Murai, Koji Fujita, and Katsuhisa Tanaka. "Magnetic Properties of Amorphous Fe2O3-R2O3 (R=La, Gd and Tb) Thin Films Fabricated by Sputtering Method." Advanced Materials Research 39-40 (April 2008): 207–12. http://dx.doi.org/10.4028/www.scientific.net/amr.39-40.207.
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Amorphous oxide thin films of Fe2O3-R2O3 (R = La, Gd and Tb) systems have been deposited on silica glass substrates by using a radio frequency sputtering method, and magnetic properties of the thin films have been examined. The Fe2O3-La2O3 thin films exhibit cusp-like maxima of dc magnetic susceptibility in their temperature dependences as well as magnetic aging and memory effects characteristic of typical spin glasses. For Fe2O3-Gd2O3 and Fe2O3-Tb2O3 systems, magnetic moments of iron ions take part in formation of a spin glass state, as indicated by the magnetic aging effects, while those of rare-earth ions remain to be in a paramagnetic state even at very low temperatures.
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Kundt, Wolfgang. "How well are Neutron Stars understood?" International Astronomical Union Colloquium 177 (2000): 597–98. http://dx.doi.org/10.1017/s025292110006070x.
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AbstractAlternative ways are discussed in which pulsars may (1) drive their winds, (2) avoid net electric currents, (3) emit coherent radio pulses, (4) acquire high spin rates, and (5) deal with moderate surface magnetic fields: 1011<B/G≲ 1014.
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Iryo, Yasuhiko, Toshinori Hirai, Yutaka Kai, Masanobu Nakamura, Yoshinori Shigematsu, Mika Kitajima, Minako Azuma, Masanori Komi, Kosuke Morita, and Yasuyuki Yamashita. "Intracranial Dural Arteriovenous Fistulas: Evaluation with 3-T Four-dimensional MR Angiography Using Arterial Spin Labeling." Radiology 271, no. 1 (April 2014): 193–99. http://dx.doi.org/10.1148/radiol.13122670.
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Stanway, E. R., T. R. Marsh, P. Chote, B. T. Gänsicke, D. Steeghs, and P. J. Wheatley. "VLA radio observations of AR Scorpii." Astronomy & Astrophysics 611 (March 2018): A66. http://dx.doi.org/10.1051/0004-6361/201732380.
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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.
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Wu, Wen-Chau, Mao-Yuan Su, Chin-Cheng Chang, Wen-Yih Isaac Tseng, and Kao-Lang Liu. "Renal Perfusion 3-T MR Imaging: A Comparative Study of Arterial Spin Labeling and Dynamic Contrast-enhanced Techniques." Radiology 261, no. 3 (December 2011): 845–53. http://dx.doi.org/10.1148/radiol.11110668.
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Delheij, P. P. J., D. C. Healey, and G. D. Wait. "The frozen spin orientation of deuterium nuclei irradiated at radio-frequencies." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 251, no. 3 (November 1986): 498–510. http://dx.doi.org/10.1016/0168-9002(86)90644-3.
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van der Maarel, Johan R. C. "Thermal relaxation and coherence dynamics of spin 3/2. II. Strong radio-frequency field." Concepts in Magnetic Resonance 19A, no. 2 (2003): 117–33. http://dx.doi.org/10.1002/cmr.a.10088.
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Brunklaus, Gunther, Jerry C. C. Chan, and Hellmut Eckert. "Solid State NMR Connectivity Studies in Dipolarly Coupled Inorganic Networks: Site Assignments in the Solid Electrolyte Material (CuI)8P12." Zeitschrift für Physikalische Chemie 217, no. 12 (December 1, 2003): 1627–40. http://dx.doi.org/10.1524/zpch.217.12.1627.20469.
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AbstractThe local structure of the fast solid ion conductor Cu2P3I2 = (CuI)8P12 is investigated using one- and two-dimensional 31P and 65Cu magic-angle spinning NMR techniques. Peak assignments are proposed on the basis of anisotropic and isotropic spin-spin interactions recovered via radio frequency driven dipolar recoupling (RFDR) and total through bond correlation spectroscopy (TOBSY) methods. Especially the previously proposed R30614 pulse symmetry (R-TOBSY), which exploits scalar spin-spin interactions for coherence transfer, offers outstanding spectral selectivity with respect to 1J coupling. Using sufficiently short mixing times it is thus possible to correlate selectively those 31P spins that are directly bonded, thereby providing detailed insights into phosphorus-phosphorus connectivities in the network. The final assignment of the nine resolved 31P resonances to the twelve crystallographically distinct phosphorus sites suggests a significant relationship between 31P chemical shifts and the detailed pyramidal P(P1/3)3 bonding geometry.
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Hu, Guoqiang. "Study on the Signal Transmission Characteristics of 2.4GHz Wireless Network in Dorms." International Journal of Online Engineering (iJOE) 12, no. 10 (October 31, 2016): 58. http://dx.doi.org/10.3991/ijoe.v12i10.6208.
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<p><span style="font-size: small;"><span style="font-family: Times New Roman;">In accordance with the deployment requirements of WLAN node in college student dorms and its features of application environment, this paper studies the relevance among factors like radio-frequency signal transmission characteristics, communication distance, AP height and transmission path, etc., with a case study of AP radio frequency 2.4GHz. Experiments show that the attenuation of wireless network signal in student dorms conforms to Keenan-Motley model. When AP is fixed, the signal strength received by laptop generally reduces with the increase of communication distance, yet just opposite with packet loss rate. When deploying AP, 1.25-1.75 height is ideal, and one-side coverage of 3 dorm rooms optimal. Based on the above researches, a relational model of AP height, communication distance and received signal strength is established. In it, model parameter and AP height display a cubic polynomial relationship, and attenuation coefficient and AP height show a quadratic polynomial relationship. Experiment results demonstrate that this model can satisfactorily predict the received signal strength of different AP heights and communication distances, providing technical support for wireless network deployment in student dorms. </span></span></p>
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Yun, M. S., P. T. P. Ho, and K. Y. Lo. "3.21. Atomic ISM in the nuclear starburst regions of M82 & NGC 253." Symposium - International Astronomical Union 184 (1998): 131–32. http://dx.doi.org/10.1017/s0074180900084345.
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M82 (NGC 3034) is a nearby (D = 3.3 Mpc) “prototypical” starburst galaxy which emits most of its luminosity in the infrared (LIR = 3×1010L⊙, see Rieke et al. 1980). M82 is also a strong radio source 3C 231, with numerous compact knots which are thought to be young SNR's (Kronberg et al., 1981; Muxlow et al., 1994). Its strong 1.4 GHz radio continuum is extended over the entire 500 pc nuclear starburst region, and the HI absorption is easily mapped at 2″ (30 pc) resolution using the VLA. The resulting velocity integrated optical depth (τΔV) map can be converted to HI column density map if HI spin temperature (Tsp) is known.
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Gregory, P. C. "Radio hot spot in supernova remnant G109.1-1.0." Canadian Journal of Physics 64, no. 4 (April 1, 1986): 479–81. http://dx.doi.org/10.1139/p86-088.
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High-resolution, very large array observations of a radio hot spot in the supernova remnant G109.1-1.0 were carried out in January 1981 and August 1984 at 6 and 20 cm to examine the possible relationship of this source to the remnant and nearby binary X-ray pulsar. The structure, spectrum, and absence of variability over a 3-year time span are consistent with a background quasar or galaxy. The source, 2258 + 586, exhibits an unresolved core that is self-absorbed at 20 cm and a one-sided jet. A very faint object appears on the red print of the Palomar sky survey, 3.7 ± 1.7 arcsec from the unresolved core.
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Liodakis, I. "Toy model for the acceleration of blazar jets." Astronomy & Astrophysics 616 (August 2018): A93. http://dx.doi.org/10.1051/0004-6361/201832766.
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Context. Understanding the acceleration mechanism of astrophysical jets has been a cumbersome endeavor from both the theoretical and observational perspective. Although several breakthroughs have been achieved in recent years, on all sides, we are still missing a comprehensive model for the acceleration of astrophysical jets. Aims. In this work we attempt to construct a simple toy model that can account for several observational and theoretical results and allow us to probe different aspects of blazar jets usually inaccessible to observations. Methods. We used the toy model and Lorentz factor estimates from the literature to constrain the black hole spin and external pressure gradient distributions of blazars. Results. Our results show that (1) the model can reproduce the velocity, spin and external pressure gradient of the jet in M 87 inferred independently by observations; (2) blazars host highly spinning black holes with 99% of BL Lac objects and 80% of flat spectrum radio quasars having spins a > 0.6; (3) the dichotomy between BL Lac objects and flat spectrum radio quasars could be attributed to their respective accretion rates. Using the results of the proposed model, we estimated the spin and external pressure gradient for 75 blazars.
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Sklyar, Anna, Nikolay Sinyavsky, Michal Ostafin, and Boleslaw Nogaj. "Application of the Elliptically Polarized Radio Frequency Fields in Spin-3/2 Nuclear Quadrupole Resonance Spectroscopy." Zeitschrift für Naturforschung A 64, no. 9-10 (October 1, 2009): 618–24. http://dx.doi.org/10.1515/zna-2009-9-1013.
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A possibility to excite the spin-3/2 quadrupolar nuclei in sites with a non-zero asymmetry parameter of the electric field gradient (EFG) tensor by means of an elliptically polarized radio frequency (RF) magnetic fields is discussed. Closed analytical formulas for the intensities of nuclear quadrupole resonance (NQR) nutation spectra and nutation frequencies of powder samples were obtained. Characteristic singularities in the nutation spectra were determined which allow the measurement of the asymmetry parameter η. It was found that in the general case of η ≠ 0 the excitation of the nuclearspins in +m and −m states by using the circularly polarized RF fields is not fully selective.
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van den Eijnden, J., N. Degenaar, T. D. Russell, R. Wijnands, A. Bahramian, J. C. A. Miller-Jones, J. V. Hernández Santisteban, et al. "A new radio census of neutron star X-ray binaries." Monthly Notices of the Royal Astronomical Society 507, no. 3 (July 21, 2021): 3899–922. http://dx.doi.org/10.1093/mnras/stab1995.
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ABSTRACT We report new radio observations of a sample of 36 neutron star (NS) X-ray binaries, more than doubling the sample in the literature observed at current-day sensitivities. These sources include 13 weakly magnetized (B < 1010 G) and 23 strongly magnetized (B ≥ 1010 G) NSs. 16 of the latter category reside in high-mass X-ray binaries, of which only two systems were radio-detected previously. We detect four weakly and nine strongly magnetized NSs; the latter are systematically radio fainter than the former and do not exceed LR ≈ 3 × 1028 erg s−1. In turn, we confirm the earlier finding that the weakly magnetized NSs are typically radio fainter than accreting stellar-mass black holes. While an unambiguous identification of the origin of radio emission in high-mass X-ray binaries is challenging, we find that in all but two detected sources (Vela X-1 and 4U 1700-37) the radio emission appears more likely attributable to a jet than the donor star wind. The strongly magnetized NS sample does not reveal a global correlation between X-ray and radio luminosity, which may be a result of sensitivity limits. Furthermore, we discuss the effect of NS spin and magnetic field on radio luminosity and jet power in our sample. No current model can account for all observed properties, necessitating the development and refinement of NS jet models to include magnetic field strengths up to 1013 G. Finally, we discuss jet quenching in soft states of NS low-mass X-ray binaries, the radio non-detections of all observed very-faint X-ray binaries in our sample, and future radio campaigns of accreting NSs.
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Sanidas, S., S. Cooper, C. G. Bassa, J. W. T. Hessels, V. I. Kondratiev, D. Michilli, B. W. Stappers, et al. "The LOFAR Tied-Array All-Sky Survey (LOTAAS): Survey overview and initial pulsar discoveries." Astronomy & Astrophysics 626 (June 2019): A104. http://dx.doi.org/10.1051/0004-6361/201935609.
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We present an overview of the LOFAR Tied-Array All-Sky Survey (LOTAAS) for radio pulsars and fast transients. The survey uses the high-band antennas of the LOFAR Superterp, the dense inner part of the LOFAR core, to survey the northern sky (δ > 0°) at a central observing frequency of 135 MHz. A total of 219 tied-array beams (coherent summation of station signals, covering 12 square degrees), as well as three incoherent beams (covering 67 square degrees) are formed in each survey pointing. For each of the 222 beams, total intensity is recorded at 491.52 μs time resolution. Each observation integrates for 1 hr and covers 2592 channels from 119 to 151 MHz. This instrumental setup allows LOTAAS to reach a detection threshold of 1–5 mJy for periodic emission. Thus far, the LOTAAS survey has resulted in the discovery of 73 radio pulsars. Among these are two mildly recycled binary millisecond pulsars (P = 13 and 33 ms), as well as the slowest-spinning radio pulsar currently known (P = 23.5 s). The survey has thus far detected 311 known pulsars, with spin periods ranging from 4 ms to 5.0 s and dispersion measures from 3.0 to 217 pc cm−3. Known pulsars are detected at flux densities consistent with literature values. We find that the LOTAAS pulsar discoveries have, on average, longer spin periods than the known pulsar population. This may reflect different selection biases between LOTAAS and previous surveys, though it is also possible that slower-spinning pulsars preferentially have steeper radio spectra. LOTAAS is the deepest all-sky pulsar survey using a digital aperture array; we discuss some of the lessons learned that can inform the approach for similar surveys using future radio telescopes such as the Square Kilometre Array.
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Morello, V., E. F. Keane, T. Enoto, S. Guillot, W. C. G. Ho, A. Jameson, M. Kramer, et al. "The SUrvey for Pulsars and Extragalactic Radio Bursts – IV. Discovery and polarimetry of a 12.1-s radio pulsar." Monthly Notices of the Royal Astronomical Society 493, no. 1 (February 5, 2020): 1165–77. http://dx.doi.org/10.1093/mnras/staa321.
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ABSTRACT We report the discovery of PSR J2251−3711, a radio pulsar with a spin period of 12.1 s, the second longest currently known. Its timing parameters imply a characteristic age of 15 Myr, a surface magnetic field of 1.3 × 1013 G, and a spin-down luminosity of 2.9 × 1029 erg s−1. Its dispersion measure of 12.12(1) pc cm−3 leads to distance estimates of 0.5 and 1.3 kpc according to the NE2001 and YMW16 Galactic free electron density models, respectively. Some of its single pulses show an uninterrupted 180-deg sweep of the phase-resolved polarization position angle, with an S-shape reminiscent of the rotating vector model prediction. However, the fact that this sweep occurs at different phases from one pulse to another is remarkable and without straightforward explanation. Although PSR J2251−3711 lies in the region of the $P-\dot{P}$ parameter space occupied by the X-ray isolated neutron stars (XINS), there is no evidence for an X-ray counterpart in our Swift XRT observation; this places a 99 per cent-confidence upper bound on its unabsorbed bolometric thermal luminosity of $1.1 \times 10^{31}~(d / 1~\mathrm{kpc})^2~\mathrm{erg\, s}^{-1}$ for an assumed temperature of 85 eV, where d is the distance to the pulsar. Further observations are needed to determine whether it is a rotation-powered pulsar with a true age of at least several Myr, or a much younger object such as an XINS or a recently cooled magnetar. Extreme specimens like PSR J2251−3711 help bridge populations in the so-called neutron star zoo in an attempt to understand their origins and evolution.
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M. A. Eid, Mahmoud, Ashraf S. Seliem, Ahmed Nabih Zaki Rashed, Abd El-Naser A. Mohammed, Mohamed Yassin Ali, and Shaimaa S. Abaza. "Duobinary modulation/predistortion techniques effects on high bit rate radio over fiber systems." Indonesian Journal of Electrical Engineering and Computer Science 21, no. 2 (February 1, 2021): 978. http://dx.doi.org/10.11591/ijeecs.v21.i2.pp978-986.
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<span>The work has presented duobinary modulation and predistortion techniques for the radio over fiber system enhancement for achieving security level. Duobinary modulation technique has more compact modulated spectral linewidth with standard non return to zero modulation code. Different NRZ/RZ rectangle shape employed that are namely exponential rectangle shape (ERS), and Gaussian rectangle shape (GRS) for different transmission bit rates. Switching bias voltage, and switching RF voltage based LiNbO<sub>3</sub> modulator are changed to measure the performance parameters of the radio over fiber (RoF) system. Predistortion technique improves the linearity of transmitter amplifiers and it is considered as a power efficiency technique. The optimum values of the Q-factor, data error rate (BER), electrical power, signal gain, noise figure, and light signal/noise ratio are achieved with 8 Volt for both switching biases/switching RF signal at 100 GHz. Signal quality/BER and electrical power after the receiver enhancement ratio by using this technique at different RF signal frequencies. </span>
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Kovalevsky, J. "Optical-Radio Reference Ties." International Astronomical Union Colloquium 165 (1997): 447–48. http://dx.doi.org/10.1017/s0252921100046935.
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In the course of the Hipparcos data reduction, the system of coordinates obtained is the result of complicated and partly random processes. It is therefore an arbitrary system which could not be retained. It was decided to compute a rotation ϵ at epoch (1991.25) and a time-dependent rotation ω (or spin) such that, when applied, it would be a realisation of the IAU extragalactic reference system as defined in 1991 and implemented by IERS in 1995.A working group was set up by the Hipparcos Science Team with the task to provide these rotations from all possible techniques. Actually eleven independent teams provided a solution. One can group them in four categories.1.Radio techniques included VLBI observations with the US Deep Space Network, VLBA and the European VLBI Network, and connected radio interferometers MERLIN and VLA. While VLBI provided a solution for both ϵ and ω, the other techniques allowed to get only ϵ.2.Medium and small field astrometry including the optical positions of compact sources (Hamburg and USNO), and observations with the HST which both provided solutions for ϵ only and comparisons of plates taken at large intervals of time (Bonn and Potsdam) which gave solutions for ω only.3.Star catalogues refered to galaxies: Lick Northern proper motion program, Yale Southern proper motion program, and KSZ catalogue. Yale University, ARI in Heidelberg and Kiev Observatory yielded solutions for ω.4.Comparison of Earth rotation parameters as obtained by VLBI and by a reduction of ground-based determinations with Hipparcos data (Prague Observatory) gave components of ϵ and ω in the equator.
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Cibuļs, Juris. "LATGALIANNESS – THE SECOND, ADDITIONAL OR THE ONLY NATIONAL IDENTITY." Via Latgalica, no. 4 (December 31, 2012): 126. http://dx.doi.org/10.17770/latg2012.4.1684.
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<p>The main objective of this article is to stress and to prove that the Latgalian national identity is the only national identity for a lot of citizens of Latvia and it is not the second or the additional identity that may be attributed only to secret service men inter alia.</p><p>My personal studies of official sources, literature and correspondence with officials of state institutions, etc. are at the basis of this article.</p><p>National identity is the person’s identity and sense of belonging to one state or to one nation, a feeling one shares with a group of people, regardless of one’s status of citizenship.</p><p>National identity is not inborn trait; various studies have shown that a person’s national identity is a direct result of the presence of elements from the „common points” in people’s daily lives: national symbols, language, national colours, the nation’s history, national consciousness, culture, music, cuisine, radio, television, etc.</p><p>There are cases where national identity collides with a person’s civil identity. For example, many Israeli Arabs associate themselves or are associated with the Arab or Palestinian nationality, while at the same time they are citizens of the state of Israel, which is in conflict with the Palestinians and with many Arab countries.</p><p>There are also cases in which the national identity of a particular group is oppressed by the government in the country where the group lives. A notable example was in Spain under the authoritarian dictatorship of Francisco Franco (1939–1947) who abolished the official statute and recognition for the Basque, Galician, and Catalan languages for the first time in the history of Spain and returned to Spanish (Castillian) as the only official language of the State and education, although millions of citizens of Spain spoke other languages.</p><p>During the first independence period of Latvia in the thirties, the schools of Latgale used Latgalian as the language of instruction during the first four years, Latgalian language was taught as a subject starting with the third year twice a week. After the coup d’état on May 15, 1934 the Latgalian textbooks were withdrawn from use and even burnt.</p><p>There is enough evidence to prove that the Latvian nationalist elite was very unwilling to accept the spread of Latgalian both during the first period of independence and the multinational Soviet rule. The positive expression of one’s national identity is patriotism, and the negative is chauvinism.</p><p>Latgalians are an autochthonous people living mostly in the eastern part of the contemporary Latvia. As regards Latgalian (it has been named in different ways – language, dialect, subdialect, foreign language, but it does not change the essence of the phenomenon) various resolutions, decrees etc. have been passed and adopted.</p><p>Participants of the 2nd Conference on Latgalistics (Rezekne, October 17, 2009) adopted the resolution „On the Status of a Regional Language to Be Attributable to the Latgalian Language”.</p><p>In accordance with the new Official Language Law enacted on September 1, 2000 the official language in Latvia is the Latvian language. Section 3 Paragraph 4 of the Law prescribes: „The State shall ensure the maintenance, protection and development of the Latgalian written language as a historic variant of the Latvian language.” However, it is a very formal statement. Strange as it may sound but the Senate of the Supreme Court of the Republic of Latvia has adopted a decision (August 18, 2009, Case No. A42571907 SKA-596/2009): „The Senate concludes that in the first sentence of Article 4 of the Satversme (the Constitution – J. C.) of the Republic of Latvia the concept „The Latvian language” means the Latvian literary language. It is the official language for the purpose of Section 110 of the Administrative Procedure Law. From the conclusion that for the purpose of Section 110 Paragraph I of the Administrative Procedure Law the official language is the Latvian literary language it follows that other subdialects or languages for the purpose of Section 110 Paragraph II of the Administrative Procedure Law are foreign languages and a document drafted in the Latgalian literary language is to be acknowledged as a document drafted in a foreign language. This decision is not to be appealed against.”</p><p>It took the Latgalian enthusiasts (I am one of them) seven years (2003–2010) to get the individual code for the Latgalian language. ISO 639/Joint Advisory Committee (Library of Congress, Washington) has finally attributed the code, namely, LTG.</p><p>Hopefully the Latgalian identity will not be swept away and this only identity for a lot of citizens of Latvia will be fought for and preserved also in the shadow of the so-called majority.</p>
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Maitra, C., P. Esposito, A. Tiengo, J. Ballet, F. Haberl, S. Dai, M. D. Filipović, and M. Pilia. "IKT 16 aka PSR J0058–7218: discovery of a 22 ms energetic rotation-powered pulsar in the Small Magellanic Cloud." Monthly Notices of the Royal Astronomical Society: Letters 507, no. 1 (June 1, 2021): L1—L5. http://dx.doi.org/10.1093/mnrasl/slab050.
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ABSTRACT We report here on the discovery with XMM–Newton of pulsations at 22 ms from the central compact source associated with IKT 16, a supernova remnant in the Small Magellanic Cloud (SMC). The measured spin period and spin period derivative correspond to 21.7661076(2) ms and 2.9(3) × 10−14 s s−1, respectively. Assuming standard spin-down by magnetic dipole radiation, the spin-down power corresponds to 1.1 × 1038 erg s−1 implying a Crab-like pulsar. This makes it the most energetic pulsar discovered in the SMC so far and a close analogue of PSR J0537–6910, a Crab-like pulsar in the Large Magellanic Cloud. The characteristic age of the pulsar is 12 kyr. Having for the first time a period measure for this source, we also searched for the signal in archival data collected in radio with the Parkes telescope and in γ-rays with the Fermi/LAT, but no evidence for pulsation was found in these energy bands.
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Yagan, Rawana, Ferhat Katmis, and Mehmet C. Onbaşlı. "Engineered Magnetization Dynamics of Magnonic Nanograting Filters." Magnetochemistry 7, no. 6 (June 3, 2021): 81. http://dx.doi.org/10.3390/magnetochemistry7060081.
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Magnonic crystals and gratings could enable tunable spin-wave filters, logic, and frequency multiplier devices. Using micromagnetic models, we investigate the effect of nanowire damping, excitation frequency and geometry on the spin wave modes, spatial and temporal transmission profiles for a finite patterned nanograting under external direct current (DC) and radio frequency (RF) magnetic fields. Studying the effect of Gilbert damping constant on the temporal and spectral responses shows that low-damping leads to longer mode propagation lengths due to low-loss and high-frequency excitations are also transmitted with high intensity. When the nanowire is excited with stronger external RF fields, higher frequency spin wave modes are transmitted with higher intensities. Changing the nanowire grating width, pitch and its number of periods helps shift the transmitted frequencies over super high-frequency (SHF) range, spans S, C, X, Ku, and K bands (3–30 GHz). Our design could enable spin-wave frequency multipliers, selective filtering, excitation, and suppression in magnetic nanowires.
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Allison, J. R., E. M. Sadler, S. Bellstedt, L. J. M. Davies, S. P. Driver, S. L. Ellison, M. Huynh, et al. "FLASH early science – discovery of an intervening H i 21-cm absorber from an ASKAP survey of the GAMA 23 field." Monthly Notices of the Royal Astronomical Society 494, no. 3 (April 9, 2020): 3627–41. http://dx.doi.org/10.1093/mnras/staa949.
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ABSTRACT We present early science results from the First Large Absorption Survey in H i (FLASH), a spectroscopically blind survey for 21-cm absorption lines in cold hydrogen (H i) gas at cosmological distances using the Australian Square Kilometre Array Pathfinder (ASKAP). We have searched for H i absorption towards 1253 radio sources in the GAMA 23 field, covering redshifts between z = 0.34 and 0.79 over a sky area of approximately 50 deg2. In a purely blind search, we did not obtain any detections of 21-cm absorbers above our reliability threshold. Assuming a fiducial value for the H i spin temperature of Tspin = 100 K and source covering fraction cf = 1, the total comoving absorption path-length sensitive to all Damped Lyman α Absorbers (DLAs; NH i ≥ 2 × 1020 cm−2) is ΔX = 6.6 ± 0.3 (Δz = 3.7 ± 0.2) and super-DLAs (NH i ≥ 2 × 1021 cm−2) is ΔX = 111 ± 6 (Δz= 63 ± 3). We estimate upper limits on the H i column density frequency distribution function that are consistent with measurements from prior surveys for redshifted optical DLAs, and nearby 21-cm emission and absorption. By cross-matching our sample of radio sources with optical spectroscopic identifications of galaxies in the GAMA 23 field, we were able to detect 21-cm absorption at z = 0.3562 towards NVSS J224500−343030, with a column density of $N_{\rm H\,\small{I}} = (1.2 \pm 0.1) \times 10^{20}\, (T_{\rm spin}/100\, \mathrm{K})$ cm−2. The absorber is associated with GAMA J22450.05−343031.7, a massive early-type galaxy at an impact parameter of 17 kpc with respect to the radio source and which may contain a massive (MH i ≳ 3 × 109 M⊙) gas disc. Such gas-rich early types are rare, but have been detected in the nearby Universe.
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Back, PJ, B. Bleaney, GJ Bowden, and NJ Stone. "A Nuclear Orientation Study of Terbium Ethyl Sulphate." Australian Journal of Physics 47, no. 4 (1994): 475. http://dx.doi.org/10.1071/ph940475.
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Terbium ethyl suphate (TbES) has been studied by nuclear orientation using radioactive 160Tb. It is found that (i) it is difficult to cool the terbium nuclei below ~50 mK because of the long nuclear spin-lattice relaxation time TIN; (ii) application of small magnetic fields of the order 0�1 T produces a dramatic increase in the value of TIN; the long electronic relaxation time T1E makes it difficult to determine the Curie temperature Tc in such experiments; and (iv) the saturation magnetic moment is approximately 7�35I'B. No nuclear magnetic resonance transitions were detected when radio-frequency fields at frequencies from 190 to 920 MHz were applied, but a long series of resonance absorption peaks was observed with a frequency separation of 26�3(3) MHz. Their origin ascribed to magneto-acoustic modes within magnetic domains, rather than to magnetostatic modes, magnetic spin waves, or resonances within domain walls.
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Mohd Norzeli, Syamimi, Ismarani Ismail, Norashidah Md Din, Mohd Tarmizi Ali, Ali Abd Almisreb, and Ammar Ahmed Alkahtani. "A rectangular CSRR based microstrip UHF reader patch antenna for RFID applications." Indonesian Journal of Electrical Engineering and Computer Science 17, no. 3 (March 1, 2020): 1434. http://dx.doi.org/10.11591/ijeecs.v17.i3.pp1434-1441.
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<span>This paper presents a compact microstrip ultra-high frequency (UHF) reader patch antenna with complementary split ring resonator (CSRR) for radio frequency identification (RFID). The total size of the antenna is 208 × 208 × 1.6 mm<sup>3</sup>. The proposed antenna is designed, fabricated and measured in order to verify the proposed concept. The characterization for radiation parameters, like return loss, radiation pattern and antenna gain have been done experimentally. The proposed antenna is operated at 921 MHz for and achieved a gain of 8.285 dBi. All simulations in this work have been carried out by means of the commercial computer simulation technology (CST) software. In compare to the simulated results, the measured outcomes are promised.</span>
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Décréau, P. M. E., S. Kougblénou, G. Lointier, J. L. Rauch, J. G. Trotignon, X. Vallières, P. Canu, S. Rochel Grimald, F. El-Lemdani Mazouz, and F. Darrouzet. "Remote sensing of a NTC radio source from a Cluster tilted spacecraft pair." Annales Geophysicae 31, no. 11 (November 26, 2013): 2097–121. http://dx.doi.org/10.5194/angeo-31-2097-2013.
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Abstract. The Cluster mission operated a "tilt campaign" during the month of May 2008. Two of the four identical Cluster spacecraft were placed at a close distance (~50 km) from each other and the spin axis of one of the spacecraft pair was tilted by an angle of ~46°. This gave the opportunity, for the first time in space, to measure global characteristics of AC electric field, at the sensitivity available with long boom (88 m) antennas, simultaneously from the specific configuration of the tilted pair of satellites and from the available base of three satellites placed at a large characteristic separation (~1 RE). This paper describes how global characteristics of radio waves, in this case the configuration of the electric field polarization ellipse in 3-D-space, are identified from in situ measurements of spin modulation features by the tilted pair, validating a novel experimental concept. In the event selected for analysis, non-thermal continuum (NTC) waves in the 15–25 kHz frequency range are observed from the Cluster constellation placed above the polar cap. The observed intensity variations with spin angle are those of plane waves, with an electric field polarization close to circular, at an ellipticity ratio e = 0.87. We derive the source position in 3-D by two different methods. The first one uses ray path orientation (measured by the tilted pair) combined with spectral signature of magnetic field magnitude at source. The second one is obtained via triangulation from the three spacecraft baseline, using estimation of directivity angles under assumption of circular polarization. The two results are not compatible, placing sources widely apart. We present a general study of the level of systematic errors due to the assumption of circular polarization, linked to the second approach, and show how this approach can lead to poor triangulation and wrong source positioning. The estimation derived from the first method places the NTC source region in the dawn sector, at a large L value (L ~ 10) and a medium geomagnetic latitude (35° S). We discuss these untypical results within the frame of the geophysical conditions prevailing that day, i.e. a particularly quiet long time interval, followed by a short increase of magnetic activity.
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Anderson, Joseph H., and Thomas P. Quinn. "Movements of adult coho salmon (Oncorhynchus kisutch) during colonization of newly accessible habitat." Canadian Journal of Fisheries and Aquatic Sciences 64, no. 8 (August 1, 2007): 1143–54. http://dx.doi.org/10.1139/f07-087.
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Pacific salmon (Oncorhynchus spp.) have repeatedly exploited new habitat following glacial recession and some artificial introductions, yet the initial process of colonization is poorly understood. Landsburg Diversion Dam on the Cedar River, Washington, excluded salmon from 33 km of habitat for over a century until it was modified to allow passage in 2003. Adult coho salmon (Oncorhynchus kisutch) were sampled as they entered the newly accessible habitat in the first 3 years and a subset received radio transmitters to assess spawning site selection and movement. Annual counts of coho colonists increased over time, and in 2 of 3 years, daily dam passage was positively correlated with river discharge. Contrary to our prediction that coho would spawn in tributaries, all identified spawning sites were in the mainstem Cedar River, though 38% of radio-tagged salmon entered a tributary at least temporarily. Females moved little within the new habitat (average = 5.8 km), whereas males moved extensively (average = 34.8 km), especially when females were scarce. The immediate use of the new habitat by colonists and their widespread movements suggest that exploration is an innate component of salmon breeding behavior, and restoring access to lost habitat merits prioritization as a conservation strategy.
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De Carli, Pablo, José Ignacio Oñativia, Agustin Donnddorff, Veronica Alfie, Gerardo Gallucci, and Jorge Boretto. "Artrodesis mediocarpiana: Estudio de la evolución clínico radiológica con 3 años de seguimiento mínimo. [Midcarpal fusion: clinical and radiological study on outcomes with a minimum follow-up of three years.]." Revista de la Asociación Argentina de Ortopedia y Traumatología 80, no. 4 (November 19, 2015): 274. http://dx.doi.org/10.15417/457.
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<p><span style="text-decoration: underline;">Objetivo</span>: Determinar la evolución clínica y radiológica de los pacientes tratados con artrodesis mediocarpiana con un seguimiento mínimo de 3 años.</p><p><span style="text-decoration: underline;">Material y métodos</span>: Se estudiaron los pacientes tratados en nuestro servicio mediante artrodesis mediocarpiana desde mayo de 1998. De un total de 27 se incluyeron 11 muñecas que contaban con un seguimiento mínimo de 3 años. Ocho fueron hombre y tres mujeres; la edad media fue 47 años (16 a 66) y el seguimiento promedio 6,7 años (3 a 15). La técnica utilizada fue artrodesis de 2 o 4 esquinas con resección del escafoides más injerto de radio distal. Se los evaluó clínicamente valorando dolor mediante Escala Visual Análoga (EVA), movilidad, y fuerza de puño. Se les realizó QuickDASH y radiografías de control.</p><p><span style="text-decoration: underline;">Resultados</span>: El dolor mejoró de 5/10 en reposo y 8/10 en actividad preoperatorios a 0/10 y 2/10 respectivamente. La movilidad que perdieron los pacientes con respecto al lado sano fue 39% de flexoextensión, 15% de desviación radial y 31% de desviación cubital. No hubo cambios en la pronosupinación y el QuickDASH postoperatorio fue de 10. La fuerza fue del 92% comparado con el lado contralateral. Radiológicamente 4 pacientes no presentaron cambios en la luz articular radiolunar; en los restantes hubo una disminución de la misma. Dos pacientes fueron reoperados por pseudoartrosis con injerto óseo.</p><p><span style="text-decoration: underline;">Conclusiones</span>: La artrodesis mediocarpiana mejora los síntomas, conservando el 61% de la flexoextensión, 85% de la desviación radial, 31% de la cubital y 92% de la fuerza.</p><span style="text-decoration: underline;">Nivel de Evidencia</span>: IV.
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Niell, A. E. "Geocentric Terrestrial Reference Frame Accuracy: DSN Spacecraft Tracking and VLBI/Lunar Laser Ranging." Symposium - International Astronomical Union 128 (1988): 115–20. http://dx.doi.org/10.1017/s0074180900119370.
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From a combination of 1) the location of McDonald Observatory from Lunar Laser Ranging, 2) relative station locations obtained from Very Long Baseline Interferometry (VLBI) measurements, and 3) a short tie by traditional geodesy, the geocentric coordinates of the 64 m antennas of the NASA/JPL Deep Space Network are obtained with an orientation which is related to the planetary ephemerides and to the celestial radio reference frame. Comparison with the geocentric positions of the same antennas obtained from tracking of interplanetary spacecraft shows that the two methods agree to 20 cm in distance off the spin axis and in relative longitude. The orientation difference of a 1 meter rotation about the spin axis is consistent with the error introduced into the tracking station locations due to an error in the ephemeris of Jupiter.
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Parthasarathy, A., S. Johnston, R. M. Shannon, L. Lentati, M. Bailes, S. Dai, M. Kerr, et al. "Timing of young radio pulsars – II. Braking indices and their interpretation." Monthly Notices of the Royal Astronomical Society 494, no. 2 (April 9, 2020): 2012–26. http://dx.doi.org/10.1093/mnras/staa882.
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ABSTRACT In Paper I of this series, we detected a significant value of the braking index (n) for 19 young, high-$\dot{E}$ radio pulsars using ∼10 yr of timing observations from the 64-m Parkes radio telescope. Here, we investigate this result in more detail using a Bayesian pulsar timing framework to model timing noise and to perform selection to distinguish between models containing exponential glitch recovery and braking index signatures. We show that consistent values of n are maintained with the addition of substantial archival data, even in the presence of glitches. We provide strong arguments that our measurements are unlikely due to exponential recovery signals from unseen glitches even though glitches play a key role in the evolution of a pulsar’s spin frequency. We conclude that, at least over decadal time-scales, the value of n can be significantly larger than the canonical 3 and discuss the implications for the evolution of pulsars.
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Lazzarini, A. L. Fantola, and E. Lazzarini. "On effective reactant radii in ortho-positronium oxidation and spin-exchange reactions." Journal of Physics B: Atomic, Molecular and Optical Physics 22, no. 3 (February 14, 1989): 541–52. http://dx.doi.org/10.1088/0953-4075/22/3/017.
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Dyks, J. "Artefacts of circumpolar cartography in radio pulsar polarization." Monthly Notices of the Royal Astronomical Society: Letters 495, no. 1 (April 26, 2020): L118—L122. http://dx.doi.org/10.1093/mnrasl/slaa073.
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ABSTRACT Single-pulse data on radio pulsar polarization are traditionally presented in the form of two-dimensional grey-scale patterns with the pulse longitude and polarization angle (PA) on the horizontal and vertical axis, respectively. Such diagrams reveal several enigmatic polarization effects: (1) bifurcations and loops of PA curve under central pulse components, (2) vertical spread of flux at all PA values, (3) exchange of power content between PA tracks of two orthogonal polarization modes (OPMs), and (4) peripherically flat PA swings that span more than 180 deg. It is shown that all these phenomena result from passage of observed polarization state near the pure-V pole of Poincaré sphere. Much of their complexity results from cartographic transformation from Poincaré sphere to the longitude–PA plane. An odd number of near-pole passages produce apparent replacement of OPM power in the profile wings, although the same amount of flux keeps staying in each modal patch on the Poincaré sphere. The fitting of pulsar PA curves should therefore allow for transitions between the primary (strong) and secondary (weak) PA tracks. The Stokes space (or Poincaré sphere) representation of pulsar polarization data contains crucial polarization information and needs to accompany the traditional viewing if the published figures are to be fully useful for interpretation.
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de Pellegars, Pauline, Liu Pan, Rahima Sidi-Boulenouar, Eric Nativel, Michel Zanca, Eric Alibert, Sébastien Rousset, et al. "Homogenous nuclear magnetic resonance probe using the space harmonics suppression method." Journal of Sensors and Sensor Systems 9, no. 1 (March 26, 2020): 117–25. http://dx.doi.org/10.5194/jsss-9-117-2020.
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Abstract. Nuclear magnetic resonance imaging (MRI) has became an unavoidable medical tool in spite of its poor sensitivity. This fact motivates the efforts to enhance the nuclear magnetic resonance (NMR) probe performance. Thus, the nuclear spin excitation and detection, classically performed using radio-frequency coils, are required to be highly sensitive and homogeneous. The space harmonics suppression (SHS) method, already demonstrated to construct coil producing homogenous static magnetic field, is used in this work to design radio-frequency coils. The SHS method is used to determine the distribution of the electrical conductive wires which are organized in a saddle-coil-like configuration. The theoretical study of these SHS coils allows one to expect an enhancement of the signal-to-noise ratio with respect to saddle coil. Coils prototypes were constructed and tested to measure 1H NMR signal at a low magnetic field (8 mT) and perform MRI acquired at a high magnetic field (3 T). The signal-to-noise ratios of these SHS coils are compared to the one of saddle coil and birdcage (in the 3 T case) of the same size under the same pulse sequence conditions demonstrating the performance enhancement allowed by the SHS coils.
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Chang, N., F. G. Xie, X. Liu, L. C. Ho, A.-J. Dong, Z. H. Han, and X. Wang. "Possible evidence of a universal radio/X-ray correlation in a near-complete sample of hard X-ray selected seyfert galaxies." Monthly Notices of the Royal Astronomical Society 503, no. 2 (February 25, 2021): 1987–98. http://dx.doi.org/10.1093/mnras/stab521.
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ABSTRACT Because the disc–jet coupling likely depends on various properties of sources probed, the sample control is always an important but challenging task. In this work, we re-analysed the INTEGRAL hard X-ray-selected sample of Seyfert galaxies. We only consider sources that have measurements in black hole (BH) mass, and luminosities in radio and X-rays. Our final sample includes 64 (out of the original 79) sources, consists of both bright active galactic nucleus and low-luminosity ones. The 2–10 keV X-ray Eddington ratio LX/LEdd locates in the range between ∼10−4.5 and ∼10−0.5. We first find that, because of the similarity in the LHX/LX distribution, the X-ray origin of radio-loud Seyferts may be the same to that of radio-quiet (RQ) ones, where we attribute to the hot accretion flow (or similarly, the corona). We then investigate the connections between luminosities in radio and X-rays. Since our sample suffers a selection bias of a BH mass MBH dependence on LX/LEdd, we focus on the correlation slope ξX between the radio (at 1.4 GHz) and X-ray luminosities in Eddington unit, i.e. $({L_{\rm R}}/{L_{\rm Edd}}) \propto ({L_{\rm X}}/{L_{\rm Edd}})^{\xi _{\rm X}}$. We classify the sources according to various properties, i.e. 1) Seyfert classification, 2) radio loudness, and 3) radio morphology. We find that, despite these differences in classification, all the sources in our sample are consistent with a universal correlation slope ξX (note that the normalization may be different), with ξX = 0.77 ± 0.10. This is unexpected, considering various possible radio emitters in RQ systems. For the jet (either relativistic and well collimated, or sub-relativistic and weakly collimated) interpretation, our result may suggest a common/universal but to be identified jet launching mechanism among all the Seyfert galaxies, while properties like BH spin and magnetic field strength only play secondary roles. We further estimate the jet production efficiency ηjet of Seyfert galaxies, which is $\eta _{\rm jet}\approx 1.9^{+0.9}_{-1.5}\times 10^{-4}$ on average. We also find that ηjet increases as the system goes fainter. Alternative scenarios for the radio emission in RQ systems are also discussed.
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Zhou, Yu Ping, Lin Zhao, and Jin Tao Liu. "Automatic Conversion Method of the Requirements Specification Verification for CTCS Level 3." Applied Mechanics and Materials 563 (May 2014): 248–57. http://dx.doi.org/10.4028/www.scientific.net/amm.563.248.
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Chinese Train Control System Level 3(CTCS-3) is a typical complex cyber-physical system which connects the control center, the station and the train. In order to ensure the friendly communication between the different manufacturers equipment, the high reliability is required by the CTCS-3 system. The reliability of a system can be tested with the formal verification method and a lot of formal tools have been developed, such as SPIN, VIS and NuSMV. In this paper, we describe the modeling techniques and abstractions of the control process. The required assembly unit has been specified as extended class. The required behavior has been specified as extended state machine diagrams and translated to temporal logic properties. Then, we propose a method to simplify the steps which transfer a UML model into a formal model. Moreover, the transition can be implemented with development language, where its result-the formal model-can be run by the formal tool and return an analysis result. At last, we take the Radio Block Center (RBC) Handover of CTCS-3 as an example, and the experimental results show the validity and feasibility of this method.
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Pişmiş, P., M. Manteiga, A. Mampaso, E. Recillas-Cruz, and G. Cruz-Gonzàlez. "The Nuclear Region of the Sbc Spiral Galaxy NGC 5055: A Mildly Active Nucleus." Symposium - International Astronomical Union 159 (1994): 454. http://dx.doi.org/10.1017/s0074180900176351.
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NGC 5055 is one of a list of nearby large spiral galaxies we have selected for a morphological and kinematic study of their bulges. CCD images are obtained at various spectral bands and in the Hα line using the 2.1 m reflector at San Pedro Martir observatory in México, while long-slit spectra at four different PA's are secured with the IDS spectrograph of the Isaac Newton Telescope of the observatory Roque de los Muchachos at La Palma, Spain. Some of the galaxies on our list for which observations are already performed are, aside from NGC 5055, NGC 3351, 4314, 5383 and 5915. These galaxies are not known to have active nuclei. However, we believe that activity may be a common phenomenon spanning a wide range of energetics, from the most active quasars and radio-galaxies (with jets) down to the mildest cases like our Galaxy or M31. The latter may be designated as MAGN (mildly active galactic nuclei). These ideas are treated in a review by Pişmiş (1987, Rev. Mex. Astron. Astrof. 14). The MAGN are usually nearby, and hence offer the possibility to study them in sufficient detail. It is reasonable to expect that the physical phenomenon underlying activity in galactic nuclei is one and the same, and it is essentially the global parameters such as energy at the nucleus that give rise to the different classes of AGN. Thus by studying the nearby mildly active galaxies one can construct a physically acceptable model supported by observation; such model, based on firmer grounds, can then be applied to all AGN.NGC 5055 (Sbc) with an adopted distance of 8.2 Mpc has a very bright bulge with a tenuous multiple arm structure around it, extending to 8 arcmin. Our velocity field and morphology of NGC 5055 lead to the following conclusions.1. The galaxy presents a north-south asymmetry; the southern approaching side has its isophotes closer together than at the farther side. We adopt PA 101° for the line of nodes. Our long-slit spectra cover the position angles: 58°, 101°, 112° and 155°.2. The rotation curve shows a linear region around the nucleus. At PA 101°, the line of nodes, the amplitude is 270 km s−1 between points ±5 arcsec on either side of the nucleus.3. There is high concentration of mass at the nuclear region (the bulge of the galaxy). An estimate of the mass for the region where the rotation curve is linear ±5 arcsec, is 1.5 × 108 M⊙. Burbidge et al. (1960) give a total mass of 7.6 × 1010 M⊙. The bulge density is thus found to be 500 times the average density of this galaxy.Analysis of the general velocity field based on four long-slit spectra shows an asymmetry between the East and West sides, ±5 arcsec around the nucleus of NGC 5055, suggestive of the existence of non-circular motion. Indeed evidence is found of an outflow on the west side of the Galaxy within a cone emanating from the center towards the NW with a projected radial velocity of around 80 km s−1. Thus this galaxy shows activity at its center and is a candidate for the MAGN group.
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Zhu, Bo-Tao, Li Zhang, and Jun Fang. "Multiband nonthermal radiative properties of pulsar wind nebulae." Astronomy & Astrophysics 609 (January 2018): A110. http://dx.doi.org/10.1051/0004-6361/201629108.
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Aims. The nonthermal radiative properties of 18 pulsar wind nebulae (PWNe) are studied in the 1D leptonic model. Methods. The dynamical and radiative evolution of a PWN in a nonradiative supernova remnant are self-consistently investigated in this model. The leptons (electrons/positrons) are injected with a broken power-law form, and nonthermal emission from a PWN is mainly produced by time-dependent relativistic leptons through synchrotron radiation and inverse Compton process. Results. Observed spectral energy distributions (SEDs) of all 18 PWNe are reproduced well, where the indexes of low-energy electron components lie in the range of 1.0–1.8 and those of high-energy electron components in the range of 2.1–3.1. Our results show that FX/Fγ > 10 for young PWNe; 1 <FX/Fγ ≤ 10 for evolved PWNe, except for G292.0+1.8; and FX/Fγ ≤ 1 for mature/old PWNe, except for CTA 1. Moreover, most PWNe are particle-dominated. Statistical analysis for the sample of 14 PWNe further indicate that (1) not all pulsar parameters have correlations with electron injection parameters, but electron maximum energy and PWN magnetic field correlate with the magnetic field at the light cylinder, the potential difference at the polar cap, and the spin-down power; (2) the spin-down power positively correlates with radio, X-ray, bolometric, and synchrotron luminosities, but does not correlate with gamma-ray luminosity; (3) the spin-down power positively correlates with radio, X-ray, and γ-band surface brightness; and (4) the PWN radius and the PWN age negatively correlate with X-ray luminosity, the ratio of X-ray to gamma-ray luminosities, and the synchrotron luminosity.