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Journal articles on the topic 'Longitudes'

Author: Grafiati

Published: 4 June 2021

Last updated: 15 February 2022

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1

Puerto Leguizamón, Gustavo, Jaime Andrés Vallejo Avellaneda, and Jhon Jaime Ramírez Ochoa. "Un estudio sobre distribución dinámica de longitudes de onda para redes gigabit ópticas pasivas." Revista Tecnura 18, no. 40 (May 4, 2014): 12. http://dx.doi.org/10.14483/udistrital.jour.tecnura.2014.2.a01.

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Este artículo presenta un estudio con el propósito de evaluar el impacto de la asignación dinámica de longitudes de onda en una red de acceso Gigabit óptica pasiva (GPON). En redes de acceso ópticas pasivas (PON), un terminal de línea óptico (OLT) alimenta diferentes PONs de tal forma que una longitud de onda se distribuye uniformemente entre las diferentes unidades de red óptica (ONU) en cada PON. Sin embargo, las redes PON no definen ningún tipo de comportamiento dinámico en la asignación de longitudes de onda en la red, a cambio, implementa una distribución de tipo completamente estático. En este artículo se evalúan las prestaciones de una red óptica de acceso en términos del caudal efectivo y tasa de paquetes perdidos en diferentes escenarios que describen un número dado de ONUs, presentando un comportamiento fuera de perfil con un porcentage dado de tráfico en exceso para una distribución fija de una longitud de onda y para una asignación dinámica de varias longitudes de onda. Los resultados muestran que, en una operación multicanal con cuatro longitudes de onda, el caudal efectivo se incrementa un 19% sobre el ancho de banda neto para la configuración con una longitud de onda mientras que el porcentaje de paquetes perdidos se reduce un 20,2 % cuando se compara con el escenario de distribución estática.

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2

Vinogradov, A. V. "Determining the parameters of a local coordinate system with a non-standard longitude of the central meridian. Ways to improve the accuracy of determining parameters." Geodesy and Cartography 972, no. 6 (July 20, 2021): 2–9. http://dx.doi.org/10.22389/0016-7126-2021-972-6-2-9.

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Improving the accuracy of calculating the longitude of the axial meridian, the coordinates of the starting point and the height of the local coordinate system is achieved through introducing an intermediate coordinate system. The longitude of the axial meridian of the intermediate coordinate system is chosen equal to the approximate value of the longitude of the axial meridian of the local coordinate system. The difference in longitudes of the axial meridians of the state coordinate system and the intermediate coordinate system is known. The final value of the axial meridian`s longitude of the local coordinate system relative to the longitude of the axial meridian of the state coordinate system is calculated as the sum of two longitude differences. The first is the difference between the axial meridians of the local and the intermediate coordinate systems; the second is the difference in longitudes between the axial meridians of the intermediate and the state system. The residual errors of the mathematical apparatus for calculating the longitude of the axial meridian are less than 0.005 arc seconds. The proposed technology has been tested at real works.

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3

Jacobs, Nancy J. "Latitudes and Longitudes." Safundi 5, no. 3 (July 2004): 1–25. http://dx.doi.org/10.1080/17533170400605306.

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4

Crowley, Mary. "Latitudes and Longitudes." Hastings Center Report 42, no. 6 (November 2012): inside front cover. http://dx.doi.org/10.1002/hast.84.

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5

Akala, A. O., G. K. Seemala, P. H. Doherty, C. E. Valladares, C. S. Carrano, J. Espinoza, and S. Oluyo. "Comparison of equatorial GPS-TEC observations over an African station and an American station during the minimum and ascending phases of solar cycle 24." Annales Geophysicae 31, no. 11 (November 22, 2013): 2085–96. http://dx.doi.org/10.5194/angeo-31-2085-2013.

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Abstract. GPS-TEC data were observed at the same local time at two equatorial stations on both longitudes: Lagos (6.52° N, 3.4° E, 3.04° S magnetic latitude), Nigeria; and Pucallpa (8.38° S, 74.57° W, 4.25° N magnetic latitude), Peru during the minimum (2009, 2010) and ascending (2011) phases of solar cycle 24. These data were grouped into daily, seasonal and solar activity sets. The day-to-day variations in vertical TEC (VTEC) recorded the maximum during 14:00–16:00 LT and minimum during 04:00–06:00 LT at both longitudes. Seasonally, during solar minimum, maximum VTEC values were observed during March equinox and minimum during solstices. However, during the ascending phase of the solar activity, the maximum values were recorded during the December solstice and minimum during the June solstice. VTEC also increased with solar activity at both longitudes. On longitude by longitude comparison, the African GPS station generally recorded higher VTEC values than the American GPS station. Furthermore, harmonic analysis technique was used to extract the annual and semi-annual components of the amplitudes of the TEC series at both stations. The semi-annual variations dominated the TEC series over the African equatorial station, while the annual variations dominated those over the American equatorial station. The GPS-TEC-derived averages for non-storm days were compared with the corresponding values derived by the IRI-2007 with the NeQuick topside option. The NeQuick option of IRI-2007 showed better performance at the American sector than the African sector, but generally underestimating TEC during the early morning hours at both longitudes.

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6

Thomson, N. R., M. A. Clilverd, and A. J. Smith. "Evidence of more efficient whistler-mode transmission during periods of increased magnetic activity." Annales Geophysicae 15, no. 8 (August 31, 1997): 999–1004. http://dx.doi.org/10.1007/s00585-997-0999-9.

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Abstract. In a previous study it was reported that whistler- mode signals received at Faraday, Antarctica (65°S,64°W) and Dunedin, New Zealand (46°S,171°E) with entry regions in Pacific longitudes (typically from the VLF transmitter NLK, Seattle, USA) showed an increase in transmission of wave energy as magnetic activity increased. However, signals with entry regions in Atlantic longitudes (typically from the NSS transmitter, Annapolis, USA) did not appear to show such a relationship. This paper reports the results of a study of the same two longitude ranges but with the opposite transmitter providing additional whistler-mode signal information, with L-values in the range 1.8–2.6. Transmissions from NLK once again indicate a relationship between the transmission of wave energy and magnetic activity even though the signals were propagating in Atlantic longitudes, not Pacific. Any trend in NSS events observed at Dunedin was obscured by a limited range of magnetic activity, and duct exit regions so close to the receiver that small-scale excitation effects appeared to be occurring. However, by combining data from both longitudes, i.e Pacific and Atlantic, and using only ducts with exit regions that were >500km from the receiver, NSS events were found to show the same trend as NLK events. No significant longitude-dependent or transmitter-dependent variations in duct efficiency could be detected. Duct efficiency increases by a factor of about 30 with Kp=2–8 and this result is discussed in terms of changes in wave-particle interactions and duct size.

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7

POPOV, M. V., and W. Sieber. "Single-Pulse Intensity Fluctuations by Cross-Correlation with Longitude of the Average Profile." International Astronomical Union Colloquium 128 (1992): 271–77. http://dx.doi.org/10.1017/s0002731600155313.

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Single-pulse radio emission from pulsars has been observed to vary both in intensity and position inside the pulse window. In some cases the variations show a rather regular structure (drifting subpulses). Such a regular structure can clearly be studied by fluctuation spectral analysis. The analysis has identified some particular peculiarities in the fluctuation spectra at different longitudes of the pulse window in many pulsars (Backer 1973, Page 1973, Popov and Smirnova 1982). In pulsars with complex integrated profiles (PSR 1919+21, PSR 1237+25) narrow features in the fluctuation spectra vary strongly with longitude, at some longitudes being quite undistinguishable.

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8

Stoneback, R. A., and R. A. Heelis. "Identifying equatorial ionospheric irregularities using in situ ion drifts." Annales Geophysicae 32, no. 4 (April 15, 2014): 421–29. http://dx.doi.org/10.5194/angeo-32-421-2014.

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Abstract. Previous climatological investigations of ionospheric irregularity occurrence in the equatorial ionosphere have utilized in situ measurements of plasma density to identify the presence of an irregularity. Here we use the Morlet wavelet and C/NOFS to isolate perturbations in meridional ion drifts and generate irregularity occurrence maps as a function of local time, longitude, season, and solar activity. For the low solar activity levels in 2008, the distributions identified by velocity perturbations follow normalized density perturbation (ΔN/N) maps with large occurrences after midnight into dawn over all longitudes. The velocity and normalized density occurrence maps contract in both local time and longitude with increasing solar activity. By 2011 irregularities are confined to particular longitudes expected by alignment and a few hours of local time after sunset. The variation in the occurrence of the late night irregularities with solar activity is consistent with the presence of gravity wave seeding.

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9

Amateis, Ralph L., Stephen P. Prisley, Harold E. Burkhart, and Jiping Liu. "The Effect of Physiographic Region and Geographic Locale on Predicting the Dominant Height and Basal Area of Loblolly Pine Plantations." Southern Journal of Applied Forestry 30, no. 3 (August 1, 2006): 147–53. http://dx.doi.org/10.1093/sjaf/30.3.147.

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Abstract Analysis of loblolly pine plantation permanent plot data established across the southeastern United States indicates that differences in dominant height and stand basal area may be related to geographic locale as well as physiographic region. In general, holding other factors constant,plantations at southern latitudes and eastern longitudes have less basal area than plantations at northern latitudes and western longitudes. Plantations at southern latitudes and eastern longitudes in the Atlantic Coastal Plain are generally taller than elsewhere in the Atlantic Coastal Plain.These trends were consistent for a younger population of intensively managed plantations, as well as for an older population of nonintensively managed plantations. Regression equations were developed to test the significance of geographic location on the prediction of basal area and dominantheight. Even in the presence of stand variables that are highly correlated with basal area and dominant height, latitude and longitude were highly significant predictors. Including them as predictor variables increased considerably the precision of the regression equations. South. J. Appl.For. 30(3):142–146.

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10

Lamy, Jérôme. "Le bureau des longitudes." Revue d'anthropologie des connaissances 1, 2, no. 2 (2007): 167. http://dx.doi.org/10.3917/rac.002.0167.

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11

Doe, Nicholas A. "Captain Vancouver's Longitudes – 1792." Journal of Navigation 48, no. 3 (September 1995): 374–88. http://dx.doi.org/10.1017/s0373463300012881.

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Captain George Vancouver's survey of the North Pacific coast of America has been characterized as being among the most distinguished work of its kind ever done. For three summers, he and his men worked from dawn to dusk, exploring the many inlets of the coastal mountains, any one of which, according to the theoretical geographers of the time, might have provided a long-sought-for passage to the Atlantic Ocean. Vancouver returned to England in poor health but, with the help of his brother John, he managed to complete his charts and most of the book describing his voyage before he died in 1798. He was not popular with the British Establishment and, after his death, all of his notes and personal papers were lost, as were the logs and journals of several of his officers.

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12

Olemskoy, S. V., and L. L. Kitchatinov. "Active longitudes of sunspots." Geomagnetism and Aeronomy 49, no. 7 (December 2009): 866–70. http://dx.doi.org/10.1134/s001679320907007x.

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13

Hiraiwa, T. "Proposal on the Modification of Sailing Calculations." Journal of Navigation 40, no. 1 (January 1987): 138–48. http://dx.doi.org/10.1017/s0373463300000369.

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Methods of calculating the course and the distance between two points from a knowledge of their latitudes and longitudes, or calculating the latitude and the longitude of the arrival point from the course and the distance from a known departure point, are called sailings. Middle-latitude sailing and Mercator sailing have been widely used.

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14

Grieger, B. "Quincuncial adaptive closed Kohonen (QuACK) map for the irregularly shaped comet 67P/Churyumov-Gerasimenko." Astronomy & Astrophysics 630 (September 20, 2019): A1. http://dx.doi.org/10.1051/0004-6361/201834841.

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Context. Standard global map projections cannot display the complete surface of a highly irregular body such as the Rosetta target comet 67P/Churyumov-Gerasimenko because different points on the surface can have the same longitude and latitude. Aims. We present a concept of generalized longitudes and latitudes that allows us to display the complete comet in generalized versions of any standard map projection. Methods. A self-organizing Kohonen map can be used to sample the surface of any 3D shape, but the unfolded map misses some area beyond its edges. Here, we combine two square grids into an inherently closed structure that really maps the complete surface of the comet. Beyond this, the closed map is topologically equivalent to the Peirce quincuncial projection of the world, which enables the definition of generalized longitudes and latitudes. Results. While the generalized version of any map projection does not exactly share the properties of the original, such as preservation of area or shape, it behaves very similar. In particular, the generalized version of the quincuncial projection behaves very well over most of the surface area and shares the tessellation properties with its original. Conclusions. The quincuncial adaptive closed Kohonen (QuACK) map and the concept of generalized longitudes and latitudes provide means for global maps of arbitrarily irregular shapes.

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15

Carman, Christián C. "Longomontanus’ Model for the Longitudes of Mars." Journal for the History of Astronomy 51, no. 2 (May 2020): 162–86. http://dx.doi.org/10.1177/0021828620923802.

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When at the beginning of 1600, Kepler arrived to work with Tycho Brahe, Longomontanus, Tycho’s principal assistant, who was working with a model for Mars that predicted with remarkable accuracy its longitudes at oppositions. According to Kepler, this hypothesis “represented all these oppositions within a distance of two minutes in longitude.” The model, however, was unsuccessful in predicting longitudes at other elongations from the Sun, and latitudes even at opposition. Much has been said on how Kepler developed his model after this meeting, arriving finally at the so-called first two laws published in his Astronomia Nova in 1609. By contrast, Longomontanus’ attempt, published as a final model in his Astronomia Danica, has received little scholarly attention. In this paper, I will systematically analyse and explain this model. Even if Longomontanus’ solution is not as elegant as Kepler’s, it deserves scholarly attention, both because it solves the problems posed by the model that he and Tycho were working on when Kepler arrived and because it offers an interesting though heterodox solution that, by contrast, helps to highlight the elegance and simplicity of Kepler’s own solution.

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16

Рыбак, Алексей, and Alexey Rybak. "Some peculiarities in longitude distribution of sunspot groups over last four eleven-year solar cycles." Solnechno-Zemnaya Fizika 2, no. 2 (June 17, 2016): 22–28. http://dx.doi.org/10.12737/18645.

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This paper considers a longitude distribution of sunspot groups over 1982–2013, using data from the National Geophysical Data Center (Boulder, USA). The space-time distribution of sunspot groups is analyzed in coordinate sectors calculated from heliographic longitudes of the groups. A longitude extent of a coordinate sector is compared to the average size of one active region (30–40°). Then, in each coordinate sector, evolutionary activity of sunspot groups is summarized according to Malde classification indices throughout the observation period. The longitude distribution of large sunspot groups made in such a way does not reveal anticorrelation between Northern and Southern hemispheres in sunspot cycle 23.

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17

Рыбак, Алексей, and Alexey Rybak. "Some peculiarities in longitude distribution of sunspot groups over last four eleven-year solar cycles." Solar-Terrestrial Physics 2, no. 2 (August 10, 2016): 28–36. http://dx.doi.org/10.12737/20997.

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This paper considers a longitude distribution of sunspot groups over 1982–2013, using data from the National Geophysical Data Center (Boulder, USA). The space-time distribution of sunspot groups is analyzed in coordinate sectors calculated from heliographic longitudes of the groups. A longitude extent of a coordinate sector is compared to the average size of one active region (30–40°). Then, in each coordinate sector, evolutionary activity of sunspot groups is summarized according to classification values after Malde throughout the observation period. The longitude distribution of large sunspot groups plotted in such a way does not reveal anticorrelation between Northern and Southern hemispheres in sunspot cycle 23.

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18

Jones, Alexander. "Hipparchus's Computations of Solar Longitudes." Journal for the History of Astronomy 22, no. 2 (May 1991): 101–25. http://dx.doi.org/10.1177/002182869102200201.

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19

Kawase, Sei-ichiro. "Interferometric monitoring of satellite longitudes." International Journal of Satellite Communications and Networking 23, no. 1 (2004): 67–76. http://dx.doi.org/10.1002/sat.806.

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20

Egbert, Gary D. "Sampling bias in VGP longitudes." Geophysical Research Letters 19, no. 23 (December 2, 1992): 2353–56. http://dx.doi.org/10.1029/92gl02549.

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21

Zhang, L. Y., H. N. Wang, and Z. L. Du. "Prediction of solar active longitudes." Astronomy & Astrophysics 484, no. 2 (April 16, 2008): 523–27. http://dx.doi.org/10.1051/0004-6361:200809464.

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22

Oláh, Katalin. "Active Longitudes in Close Binaries." Astrophysics and Space Science 304, no. 1-4 (July 19, 2006): 145–48. http://dx.doi.org/10.1007/s10509-006-9096-x.

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23

Thurston, Hugh. "Greek and Indian planetary longitudes." Archive for History of Exact Sciences 44, no. 3 (1992): 191–95. http://dx.doi.org/10.1007/bf00377048.

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24

Yaulema Castañeda, Jorge Luis, Paulina Fernanda Bolaños Logroño, Hector Bryan Mendez Gómez, and Valentina Orquera. "Automatización de un generador de luz ultravioleta, controlada con un HMI, de longitud de onda variable." ConcienciaDigital 3, no. 2.2 (June 5, 2020): 132–53. http://dx.doi.org/10.33262/concienciadigital.v3i2.2.1252.

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En la presente investigación, el objetivo principal fue realizar un control de longitudes de onda de luz UV, en un prototipo, analizando su óptica, cuyo referencial es el espectrofotómetro Perkin Elmer 781, usado en análisis de descontaminación de aguas surfactantes y de fotodegradación, para lo cual se ha rediseñado el generador, determinando el rango de frecuencias, disminuyendo el impacto ambiental, mediante la implementación de HMI, cuya metodología aplicada, para efectuar el proceso de automatización cuyo enfoque aplicativo se determina a través de la foto de graduación y descontaminación del agua, presentando un rediseño para la generación de longitudes de onda UV dentro de la parte eléctrica y electrónica a través de la interpolación de Newton disminuyendo el error al (0.05%) mínimos cuadrados de (3.32%) optimizando el control de motores con una conexión en HMI, mediante la cual se visualiza la longitud de onda generada facilitando la navegación y el control de los motores otorgando al operario la interacción directa con el equipo obteniendo como resultado a la mejora del sistema original variando los sensores y actuadores para obtener longitudes de onda de (500 nm) a (700 nm) el cual permite desarrollar trabajos en la descontaminación de aguas y efectividad del sistema.

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25

Usoskin, I. G., S. V. Berdyugina, and J. Poutanen. "(1) Preferred longitudes in sunspot activity (2) Preferred sunspot longitudes: non-axisymmetry and differential rotation." Astronomy & Astrophysics 464, no. 2 (December 19, 2006): 761. http://dx.doi.org/10.1051/0004-6361:20053201e.

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26

Kholshevnikov, Konstantin V., Danila V. Milanov, and Anastasia S. Shchepalova. "The space of Keplerian orbits and a family of its quotient spaces." Vestnik of Saint Petersburg University. Mathematics. Mechanics. Astronomy 8, no. 2 (2021): 359–69. http://dx.doi.org/10.21638/spbu01.2021.215.

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Distance functions on the set of Keplerian orbits play an important role in solving problems of searching for parent bodies of meteoroid streams. A special kind of such functions are distances in the quotient spaces of orbits. Three metrics of this type were developed earlier. These metrics allow to disregard the longitude of ascending node or the argument of pericenter or both. Here we introduce one more quotient space, where two orbits are considered identical if they differ only in their longitudes of nodes and arguments of pericenters, but have the same sum of these elements (the longitude of pericenter). The function q is defined to calculate distance between two equivalence classes of orbits. The algorithm for calculation of ̺6 value is provided along with a reference to the corresponding program, written in C++ language. Unfortunately, ̺6 is not a full-fledged metric. We proved that it satisfies first two axioms of metric space, but not the third one: the triangle inequality does not hold, at least in the case of large eccentricities. However there are two important particular cases when the triangle axiom is satisfied: one of three orbits is circular, longitudes of pericenters of all three orbits coincide. Perhaps the inequality holds for all elliptic orbits, but this is a matter of future research.

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27

Obridko, Vladimir N. "Large-scale patterns and ‘active longitudes’." Proceedings of the International Astronomical Union 5, S264 (August 2009): 241–50. http://dx.doi.org/10.1017/s1743921309992699.

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AbstractThe following aspects of the physics of large-scale solar magnetic fields are discussed: structure of large-scale fields (LSF) and connection with local fields; dynamo and origin of LSF; LSF cycle variation; meridional circulation and LSF; rotation of LSF; fine structure of the field in quiet regions and the concept of the pebble-shaped field; active longitudes, their manifestation in various solar indices, and dependence on the power of solar activity.

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28

Ivanov, E. V. "Active longitudes: Structure, dynamics, and rotation." Advances in Space Research 40, no. 7 (January 2007): 959–69. http://dx.doi.org/10.1016/j.asr.2007.02.093.

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29

Dobrzycki, Jerzy. "Astronomy versus cartography: Late medieval longitudes." Vistas in Astronomy 28 (January 1985): 187. http://dx.doi.org/10.1016/0083-6656(85)90024-8.

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30

Rastogi, R. G., H. Chandra, and K. Yumuto. "Equatorial electrojet in east Brazil longitudes." Journal of Earth System Science 119, no. 4 (August 2010): 497–505. http://dx.doi.org/10.1007/s12040-010-0035-4.

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31

Escot, Carmelo, and Carlos Granado-Lorencio. "Comparison of four methods of back-calculating growth using otoliths of a European barbel, Barbus sclateri (GÜnther) (Pisces : Cyprinidae)." Marine and Freshwater Research 50, no. 1 (1999): 83. http://dx.doi.org/10.1071/mf97260.

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The allometric relationship between fish length and otolith radius was determined for a European barbel, Barbus sclateri, from two natural populations. The relationship was significantly different between populations, but did not differ between females and males. The ages of the fish were determined from the otoliths, and this was used to evaluate four back-calculation procedures: Monastyrsky’s method of direct proportion; two by intercept-corrected direct proportion (Fraser-Lee’s method and the biological intercept method); and the simple regression method. The biological intercept method provided the most reliable estimates of fish lengths at previous ages when otoliths were used. Lengths back-calculated from earlier annuli of older fish were quite different from observed lengths for each age and from lengths back-calculated from recent annuli. Resumen. A dos poblaciones naturales de barbo europeo, Barbus sclateri, se les determinó la relación alométrica entre la longitud del pez y el radio del otolito. Esta relación fue significativamente diferente entre las dos localidades geográficas, e igual entre hembras y machos. Se utilizó los otolitos para determinar la edad de los peces y para evaluar cuatro procedimientos de retrocálculo: el método de Monastyrsky de proporción directa; dos de proporción directa en los que se corrige la intersección, el método de Fraser-Lee y el de intersección biológica; y el método de regresión simple. El método de intersección biológica ofrece las estimas más reales de la longitud del pez en las edades anteriores a la captura. Por otro lado, las longitudes retrocalculadas a partir de los annuli formados en primer lugar de los ejemplares más viejos, fueron diferentes a las longitudes observadas en cada edad y a las longitudes retrocalculadas a partir de los annuli formados más recientemente.

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32

Deminova, G. F. "Maps of <I>fo</I>F2, <I>hm</I>F2, and plasma frequency above F2-layer peak in the night-time low-latitude ionosphere derived from Intercosmos-19 satellite topside sounding data." Annales Geophysicae 25, no. 8 (August 29, 2007): 1827–35. http://dx.doi.org/10.5194/angeo-25-1827-2007.

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Abstract. Maps of foF2, hmF2, and plasma frequency, fp, in the topside ionosphere at low latitudes, derived from Intercosmos-19 satellite topside sounding data, obtained from March 1979 to January 1981 and covering all longitudes, are presented for quiet geomagnetic conditions in June and December solstices at solar maximum for several local time intervals during the night. Based on these maps, features of the equatorial anomaly (EA) at different longitudes and their change during the night are considered. The maps show that averaged foF2, hmF2, and fp longitudinal variations are rather complicated, their structure looks wave-like with quasi-periods in longitude of about 75–100°, similar to that on individual days revealed previously at low latitudes using Intercosmos-19 data. Positions of the structure extrema in certain longitude intervals are stable enough so that they are clearly seen in the maps after averaging over a large number of measurements made on different days and even in different years. Such structure seems to need at least five harmonics for its description. The maps derived from Intercosmos-19 data were compared with the maps given by the IRI model. Along with general resemblance, essential distinctions between them were found. Intercosmos-19 maps show more complicated and pronounced longitudinal structure than IRI maps. They also show that at solar maximum, in general, at night, EA is stronger and persists for a longer time (on average, until 04:00 LT) than that presented in IRI model. Besides, much stronger asymmetry between the characteristics of the EA northern and southern crests in certain longitude intervals was revealed, most evident in hmF2 maps.

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33

Jetsu, Lauri, Jaan Pelt, Ilkka Tuominen, and Harold Nations. "The Spot Activity of FK Comae Berenices." International Astronomical Union Colloquium 130 (1991): 381–83. http://dx.doi.org/10.1017/s0252921100079963.

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AbstractThe active regions of FK Comae Berenices show a flip-flop behaviour, i.e. the concentrated part of spot-activity shifts exactly to the other side of stellar surface, and then remains on the same longitude for a time interval from a few years to a decade. The activity shows excellent phase coherence with respect to these two active longitudes separated 180 degrees from each other. FK Comae may provide a physical example of a non-linear dynamo, which shows surprisingly simple observational changes in the pattern of the magnetically induced spot configurations.

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34

Loumou, K., I. G. Hannah, and H. S. Hudson. "The association of the Hale sector boundary with RHESSI solar flares and active longitudes." Astronomy & Astrophysics 618 (October 2018): A9. http://dx.doi.org/10.1051/0004-6361/201731050.

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Context. The heliospheric magnetic field (HMF) is structured into large sectors of positive and negative polarity. The parts of the boundary between these sectors where the change in polarity matches that of the leading-to-following sunspot polarity in that solar hemisphere, are called Hale sector boundaries (HSB). Aims. We investigate the flare occurrence rate near HSBs and the association between HSBs and active longitudes. Methods. Previous work determined the times HSBs were at solar central meridian, using the detection of the HMF sector boundary crossing at the Earth. In addition to this, we use a new approach which finds the HSB locations at all times by determining them from potential field source surface (PFSS) extrapolations of photospheric magnetograms. We use the RHESSI X-ray flare list for comparison to the HSB as it provides accurate flare locations over 14 years, from February 2002 to February 2016, covering both Cycles 23 and 24. For the active longitude positions we use previously published work based on sunspot observations. Results. We find that the two methods of determining the HSB generally agree and that 41% (Cycle 23) and 47% (Cycle 24) of RHESSI flares occur within 30° of the PFSS determined-HSB. The behaviour of the HSBs varies over the two Cycles studied, and as expected they swap in hemisphere as the Cycles change. The HSBs and active longitudes do overlap but not consistently. They often move at different rates relative to each other (and the Carrington solar rotation rate) and these vary over each Cycle. The HSBs provide a useful additional activity indicator, particularly during periods when active longitudes are difficult to determine.

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35

Caswell, JL, and RF Haynes. "Survey of OH Masers at 1665 MHz. III. Galactic Longitudes 233° to 326°." Australian Journal of Physics 40, no. 2 (1987): 215. http://dx.doi.org/10.1071/ph870215.

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We have searched the galactic plane from longitude 233� to 326� for OH emission on the 1665 MHz transition. Between longitudes 270� and 326�, where the survey zone was a uniformly sampled grid, we detected 35 OH maser sources, including 24 new ones; most are of the Type I variety that delineates sites of current star formation, and many of the sites are young, with no well-developed HII regions in the vicinity. By combining the present results with those of earlier surveys Oongitudes 326� ? 360� ? 2�: Parts I and II) we have improved on previous estimates of the galactic distribution of these masers.

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36

Getselev, I. V., M. V. Podzolko, and V. P. Okhlopkov. "Passive longitudes of solar cosmic ray sources." Bulletin of the Russian Academy of Sciences: Physics 77, no. 5 (May 2013): 503–5. http://dx.doi.org/10.3103/s1062873813050201.

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37

Chapront-Touzé, Michelle. "LES MANUSCRITS DELAMBRE DU BUREAU DES LONGITUDES." Journal for the History of Astronomy 17, no. 3 (August 1986): 183–86. http://dx.doi.org/10.1177/002182868601700302.

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38

Berdyugina, S. V., D. Moss, D. Sokoloff, and I. G. Usoskin. "Active longitudes, nonaxisymmetric dynamos and phase mixing." Astronomy & Astrophysics 445, no. 2 (December 16, 2005): 703–14. http://dx.doi.org/10.1051/0004-6361:20053454.

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39

Kostuchenko, I. G., and E. E. Benevolenskaya. "Active longitudes in minima of solar activity." Geomagnetism and Aeronomy 54, no. 8 (December 2014): 1019–25. http://dx.doi.org/10.1134/s001679321408009x.

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40

Soicher, H., F. J. Gorman, E. E. Tsedilina, and O. V. Weitsman. "Ionosphericƒ0F2values and their gradients at European longitudes." Radio Science 30, no. 3 (May 1995): 755–64. http://dx.doi.org/10.1029/94rs03178.

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41

Getselev, I. V., M. V. Podzolko, and V. P. Okhlopkov. "Passive longitudes of solar cosmic ray sources." Journal of Physics: Conference Series 409 (February 1, 2013): 012203. http://dx.doi.org/10.1088/1742-6596/409/1/012203.

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42

Zhang, L., K. Mursula, I. Usoskin, and H. Wang. "Global analysis of active longitudes of sunspots." Astronomy & Astrophysics 529 (March 22, 2011): A23. http://dx.doi.org/10.1051/0004-6361/201015255.

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43

Obridko, V. N., V. E. Chertoprud, and E. V. Ivanov. "‘Active Longitudes’ in the Heliomagnetic Reference Frame." Solar Physics 272, no. 1 (July 21, 2011): 59–71. http://dx.doi.org/10.1007/s11207-011-9813-7.

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44

Rodriguez Taboada, R. E., and G. Gil Moreno. "Are there fast-rotating giant active longitudes ?" Solar Physics 144, no. 2 (April 1993): 399–402. http://dx.doi.org/10.1007/bf00627603.

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45

Duke, Dennis W. "Mean motions and longitudes in indian astronomy." Archive for History of Exact Sciences 62, no. 5 (March 11, 2008): 489–509. http://dx.doi.org/10.1007/s00407-008-0022-1.

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46

Tiburcio Moreno, José, and Florencio Hernández. "ESTUDIO DEL PROCESO DE FOTODEGRADACION DE β-CAROTENO EN UNA SOLUCION DE TETRAHIDROFURANO (THF) USANDO ESPECTROSCOPIA DE ABSORCION OPTICA Y FLUORESCENCIA." Ciencia & Desarrollo, no. 20 (April 30, 2019): 12–15. http://dx.doi.org/10.33326/26176033.2015.20.502.

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En este trabajo, presentamos el estudio espectroscópico de la fotodegradación ultravioleta de β-caroteno en una solución de THF a dos diferentes longitudes de onda. El análisis temporal del proceso, bajo una irradiación a 366nm y 254nm, muestra una dinámica rápida a longitudes de onda cortas. Asimismo, se observa una cinética de primer orden en ambas longitudes de onda lo que confirma la descomposición unimolecular del modelo propuesto en la literatura. Este trabajo se estima a ser de relevancia en la descomposición fotoinducida para el estudio y empleo de esta molécula en la industria de antioxidantes naturales, alimentos, drogas y farmacéutica.

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47

Smirnova, T. V. "Spatial Structure Variations of Pulsar Emission Sources." International Astronomical Union Colloquium 128 (1992): 290–92. http://dx.doi.org/10.1017/s0002731600155350.

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AbstractDiffractive scintillations from large-scale irregularities of the interstellar medium were observed for 5 strong pulsars at 102.7 MHz. The shifts of the time cross-correlation function of intensity variations at different longitudes of the profile were obtained as a function of longitude separation (phase curve). The shift is defined by the transverse separation of the pulsar emission sources. The maximum values of the spatial separation are: 1-2 x 108 cm. We show that the phase curves are inconsistent with the dipole model of the magnetosphere and change from day to day not only in amplitude, but also in direction.

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48

Débarbat, Suzanne. "Des éphémérides astronomiques annuelles en préliminaire à l'Annuaire du Bureau des Longitudes." Symposium - International Astronomical Union 172 (1996): 339–44. http://dx.doi.org/10.1017/s0074180900127639.

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Le Bureau des longitudes est chargé de rédiger la connoissance des temps, qui sera imprimée aux frais de la République, de manière que l'on puisse toujours avoir les éditions de plusieurs années à l'avance; il perfectionnera les tables astronomiques, et les méthodes des longitudes, et s'occupera de la publication des observations astronomiques et météorologiques. (Extrait du Rapport sur l'établissement du Bureau des longitudes par Grégoire, Séance du 7 Messidor, l'an 3 de la République une et indivisible; Suivi du décret de la Convention nationale, et Imprimé par son ordre. Le document, de seize pages se termine par la mention: Adopté; il est dit: A Paris, De l'Imprimerie nationale, Messidor l'An III)

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49

Dal, H. A., E. Sipahi, and O. Özdarcan. "High-Level Magnetic Activity on a Low-Mass Close Binary: GSC 02038-0293." Publications of the Astronomical Society of Australia 29, no. 2 (2012): 150–60. http://dx.doi.org/10.1071/as12007.

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AbstractTaking into account results obtained from light-curve analysis and out-of-eclipse analyses, we discuss the nature of GSC 02038-00293 and also its magnetic activity behaviour.We obtained light curves of the system during observing seasons 2007, 2008 and 2011. We obtained its secondary minimum clearly in I-band observations in 2008 for the first time. Analysing this light curve, we found the physical parameters of the components. The light-curve analysis indicates that the possible mass ratio of the system is 0.35. We obtained the remaining V-band light curves, extracting the eclipses. We modelled these remaining curves using the SPOTMODEL program and found possible spot configurations of the magnetically active component for each observing season. The models demonstrated that there are two active longitudes for the active component. The models reveal that both active longitudes migrate in the direction of decreasing longitude. We also examined the light curves in out-of-eclipse phases with respect to minimum and maximum brightness, amplitude, etc. The amplitude of the curves during out-of-eclipse phases varies in a sinusoidal way with a period of ∼8.9 yr; the mean brightness of the system is dramatically decreasing. The phases of the deeper minimum during out-of-eclipse periods exhibit a migration toward decreasing phase.

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Korhonen, Heidi, and Silva P. Järvinen. "Active Longitudes and Flip-Flops in Binary Stars." Proceedings of the International Astronomical Union 2, S240 (August 2006): 453–55. http://dx.doi.org/10.1017/s1743921307004437.

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AbstractWe present results from an investigation where the long-term photometry of several magnetically active RS CVn binaries is studied to see whether or not they show permanent active longitudes and the flip-flop phenomenon. We confirm that it is very common for the active regions to occur on permanent active longitudes. Many of our target stars also show clear flip-flop phenomenon, but often the data set is not long enough for reliable determination of the flip-flop period.

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