78 research outputs found
Using ethnography and assemblage theory in political geography
While the focus on the âeverydayâ in qualitative human geography has greatly increased the need for, and relevance of, ethnographic methods, Megoran argued that this is particularly true for political geography as it has the potential to challenge its focus on elite discourse, allowing researchers to bring forward multiple voices to investigate the becoming of political events. More recently, assemblage theory has gained traction in political geography, not only because of its capability to include the role of the material and the affective, but also revealing the links between microâ and macroâpolitics by showing how agency emerges out of complex relations. In the first part of this paper, we present an overview of the recent uses of ethnography in political geography that have not embraced assemblage. Second, we explore the theoretical conceptualisations of, and opportunities provided by, an assemblage approach. Third, we go through the use of assemblage ethnographies in political geography, with a particular focus on Pooya's experience of research with Iranians in London. In this, he embraced a variety of ethnographic approaches, including âautoâethnographyâ, ânetnographiesâ, âparticipant sensationâ, in combination with observations, participatory workshops and activism. Showing the role of ethnography as a qualitative tool for political geographers to interrogate discursive social constructions, we argue that it holds even more promise for analysing and intervening in the emergent politics of socioâmaterialâaffective assemblages
GPS Phase Scintillation at High Latitudes during Geomagnetic Storms of 7â17 March 2012 â Part 1: The North American Sector
During the ascending phase of solar cycle 24, a series of interplanetary coronal mass ejections (ICMEs) in the period 7â17 March 2012 caused geomagnetic storms that strongly affected high-latitude ionosphere in the Northern and Southern Hemisphere. GPS phase scintillation was observed at northern and southern high latitudes by arrays of GPS ionospheric scintillation and TEC monitors (GISTMs) and geodetic-quality GPS receivers sampling at 1 Hz. Mapped as a function of magnetic latitude and magnetic local time, regions of enhanced scintillation are identified in the context of coupling processes between the solar wind and the magnetosphereâionosphere system. Large southward IMF and high solar wind dynamic pressure resulted in the strongest scintillation in the nightside auroral oval. Scintillation occurrence was correlated with ground magnetic field perturbations and riometer absorption enhancements, and collocated with mapped auroral emission. During periods of southward IMF, scintillation was also collocated with ionospheric convection in the expanded dawn and dusk cells, with the antisunward convection in the polar cap and with a tongue of ionization fractured into patches. In contrast, large northward IMF combined with a strong solar wind dynamic pressure pulse was followed by scintillation caused by transpolar arcs in the polar cap
GPS phase scintillation and proxy index at high latitudes during a moderate geomagnetic storm
The amplitude and phase scintillation indices are customarily obtained by specialised GPS Ionospheric Scintillation and TEC Monitors (GISTMs) from L1 signal recorded at the rate of 50 Hz. The scintillation indices S[subscript 4] and Ï[subscript Ί] are stored in real time from an array of high-rate scintillation receivers of the Canadian High Arctic Ionospheric Network (CHAIN). Ionospheric phase scintillation was observed at high latitudes during a moderate geomagnetic storm (Dst = â61 nT) that was caused by a moderate solar wind plasma stream compounded with the impact of two coronal mass ejections. The most intense phase scintillation (Ï[subscript Ί] ~ 1 rad) occurred in the cusp and the polar cap where it was co-located with a strong ionospheric convection, an extended tongue of ionisation and dense polar cap patches that were observed with ionosondes and HF radars. At sub-auroral latitudes, a sub-auroral polarisation stream that was observed by mid-latitude radars was associated with weak scintillation (defined arbitrarily as Ï[subscript Ί] 0.1 rad and DPR > 2 mm s[superscript â1], both mapped as a function of magnetic latitude and magnetic local time, are very similar.National Science Foundation (U.S.) (Grant ATM-0856093
GPS phase scintillation at high latitudes during the geomagnetic storm of 17-18 March 2015:GPS Scintillation at High Latitudes
GPS phase scintillation at high latitudes during geomagnetic storms of 7-17 March 2012, part 2: interhemispheric comparison
During the ascending phase of solar cycle 24, a series of interplanetary coronal mass ejections (ICMEs) in the period 7â17 March 2012 caused geomagnetic storms that strongly affected high-latitude ionosphere in the Northern and Southern Hemisphere. GPS phase scintillation was observed at northern and southern high latitudes by arrays of GPS ionospheric scintillation and TEC monitors (GISTMs) and geodetic-quality GPS receivers sampling at 1 Hz. Mapped as a function of magnetic latitude and magnetic local time (MLT), the scintillation was observed in the ionospheric cusp, the tongue of ionization fragmented into patches, sun-aligned arcs in the polar cap, and nightside auroral oval and subauroral latitudes. Complementing a companion paper (Prikryl et al., 2015a) that focuses on the high latitude ionospheric response to variable solar wind in the North American sector, interhemispheric comparison reveals commonalities as well as differences and asymmetries between the northern and southern high latitudes, as a consequence of the coupling between the solar wind and magnetosphere. The interhemispheric asymmetries are caused by the dawnâdusk component of the interplanetary magnetic field controlling the MLT of the cusp entry of the storm enhanced density plasma into the polar cap and the orientation relative to the noonâmidnight meridian of the tongue of ionization
An interhemispheric comparison of GPS phase scintillation with auroral emission observed at the South Pole and from the DMSP satellite
The global positioning system (GPS) phase scintillation caused by highlatitude
ionospheric irregularities during an intense high-speed stream (HSS) of the solar wind from April 29 to May 5, 2011, was observed using arrays of GPS ionospheric scintillation and total electron content monitors in the Arctic and Antarctica. The one-minute phase-scintillation index derived from the data sampled at 50 Hz was complemented by a proxy index (delta phase rate) obtained from 1-Hz GPS data. The scintillation occurrence coincided with the aurora borealis and aurora australis
observed by an all-sky imager at the South Pole, and by special sensor ultraviolet scanning imagers on board satellites of the Defense Meteorological Satellites Program. The South Pole (SP) station is approximately
conjugate with two Canadian High Arctic Ionospheric Network stations on Baffin Island, Canada, which provided the opportunity to study magnetic conjugacy of scintillation with support of riometers and
magnetometers. The GPS ionospheric pierce points were mapped at their actual or conjugate locations, along with the auroral emission over the South Pole, assuming an altitude of 120 km. As the aurora brightened
and/or drifted across the field of view of the all-sky imager, sequences of
scintillation events were observed that indicated conjugate auroras as a
locator of simultaneous or delayed bipolar scintillation events. In spite of the greater scintillation intensity in the auroral oval, where phase scintillation
sometimes exceeded 1 radian during the auroral break-up and substorms, the percentage occurrence of moderate scintillation was highest in the cusp. Interhemispheric comparisons of bipolar scintillation maps show that the scintillation occurrence is significantly higher in the southern cusp and polar cap
Software project planning through comparison of Bio-inspired algorithms
Currently many organizations have adopted the development of software projects with agile methodologies, particularly Scrum, which has more than 20 years of development. In these methodologies, software is developed iteratively and delivered to the client in increments called releases. In the releases, the goal is to develop system functionality that quickly adds value to the clientâs business. At the beginning of the project, one or more releases are planned. For solving the problem of replanning in the context of releases, a model is proposed considering the characteristics of agile development using Scrum. The results obtained show that the algorithm takes a little less than 7 min for solutions that propose replanning composed by 16 sprints, which is equivalent to 240 days of project. They show that applying a repair operator increases the hypervolume qualit
GPS phase scintillation during the geomagnetic storm of March 17, 2015: The relation to auroral electrojet currents
GPS phase scintillation at high latitudes during geomagnetic storms of 7â17 March 2012 â Part 1: The North American sector
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