1,222 research outputs found
New approaches to Spanish anarchism
© 2016 Intellect Ltd Introduction. This article introduces the themes of this special edition, presenting the case that the history of Spanish anarchism needs to be situated within a broader, international history of the left. This view helps to disrupt the image of anarchism as 'exceptional', without losing sight of its specific manifestation in Spain. It proceeds to outline the five articles that make up the remainder of the edition
Cluster spacecraft observations of a ULF wave enhanced by Space Plasma Exploration by Active Radar (SPEAR)
Space Plasma Exploration by Active Radar (SPEAR) is a high-latitude ionospheric heating facility capable of exciting ULF waves on local magnetic field lines. We examine an interval from 1 February 2006 when SPEAR was transmitting a 1 Hz modulation signal with a 10 min on-off cycle. Ground magnetometer data indicated that SPEAR modulated currents in the local ionosphere at 1 Hz, and enhanced a natural field line resonance with a 10 min period. During this interval the Cluster spacecraft passed over the heater site. Signatures of the SPEAR-enhanced field line resonance were present in the magnetic field data measured by the magnetometer on-board Cluster-2. These are the first joint ground- and space-based detections of field line tagging by SPEAR
The response of the magnetosphere to the passage of a coronal mass ejection on March 20-21 1990
International audienceThe geomagnetic response to the passage of a coronal mass ejection (CME) is studied. The passage of the CME resulted in a storm sudden commencement (SSC) at 2243 UT on March 20 1990 with disturbed magnetic activity during the following 24 h. The auroral, sub-auroral and equatorial magnetic response to the southward turning at 1314 (±5) UT on March 21 and the equatorial response to the southward turning associated with the SSC on 20 March are discussed in terms of existing models. It is found that the auroral and sub-auroral response to the southward turning associated with the SSC is a factor 2 or more quicker than normal due to the shock in the solar wind dynamic pressure. The low-latitude response time to the southward turning, characterised by Dst and the magnetopause current corrected Dst*, is unaffected by the shock. Dst and Dst*, characteristic of the equatorial magnetic field, responded to the 1314 (±5) UT southward turning prior to the first observed substorm expansion phase onset, suggesting that a dayside loading process was responsible for the initial enhancement in the ring current rather than nightside particle injection. The response time of the auroral and sub-auroral magnetic field to the southward turning at 1314 (±5) UT on March 21 is measured at a variety of longitudes and latitudes. The azimuthal propagation velocity of the response to the southward turning varied considerably with latitude, ranging from ~8 km s?1 at 67°N to ~4 km s?1 at 55°N. The southward velocity of the equatorward boundary of the northern polar convection pattern has been measured. This velocity was ~1.2 km s?1 at 1600 MLT, although there was evidence that this may vary at different local times
Modulation of radio frequency signals by ULF waves
The ionospheric plasma is continually perturbed by ultra-low frequency (ULF; 1&ndash;100 mHz) plasma waves that are incident from the magnetosphere. In this paper we present a combined experimental and modeling study of the variation in radio frequency of signals propagating in the ionosphere due to the interaction of ULF wave energy with the ionospheric plasma. Modeling the interaction shows that the magnitude of the ULF wave electric field, <B>e</B>, and the geomagnetic field, <B>B</B><sub>0</sub>, giving an <B>e</B>&times;<B>B</B><sub>0</sub> drift, is the dominant mechanism for changing the radio frequency. We also show how data from high frequency (HF) Doppler sounders can be combined with HF radar data to provide details of the spatial structure of ULF wave energy in the ionosphere. Due to spatial averaging effects, the spatial structure of ULF waves measured in the ionosphere may be quite different to that obtained using ground based magnetometer arrays. The ULF wave spatial structure is shown to be a critical parameter that determines how ULF wave effects alter the frequency of HF signals propagating through the ionosphere
‘Just Google It?’: Pupils’ Perceptions and Experience of Research in the Secondary Classroom
While numerous studies examine perceptions of research held by university researchers, studies examining perceptions held by school pupils are rare. To address this gap and following analysis of questionnaire data (N = 2634, KS3/4/5 pupils), we conducted 11 group interviews with 100 pupils in England to investigate their experiences of research during schooling and their perceptions of how research is conceived, conducted and where its utility and significance lie. Thematic analysis of the interview data – informed by Angela Brew’s 4-tier descriptor of perceptions of research (domino, trading, layer, journey), Jenni Stubb's and colleagues' elaboration of this descriptor, Jan Meyer's and colleagues' conceptions of research inventory (CoRI) and Diane Bills’ distinction between Research and research – led to seven themes. Here we elaborate the most significant of these themes: fact finding as research; who formulates and owns a research question; and the friction between uninformed opinion and informed view. We conclude that secondary pupils’ experiences and perceptions of research, while overall relatively rich, vary across different disciplines. We also conclude that pupils would benefit substantially from more comprehensive engagement with research processes, and we observe the role that qualifications such as the Extended Project Qualification can play in fostering said engagement
Observations and modelling of the wave mode evolution of an impulse-driven 3 mHz ULF wave
A combination of an HF Doppler sounder, a network of ground magnetometers,
upstream solar wind monitors and a numerical model is used to examine the
temporal evolution of an Ultra Low Frequency (ULF) wave. The event occurred
on 16 April 1998 and followed a solar wind density and pressure increase seen
in the upstream ACE spacecraft data. The magnetometer and HF Doppler sounder
data show that the event develops into a low-<I>m</I> (−6) field line
resonance. HF signals that propagate via the ionosphere exhibit Doppler
shifts due to a number of processes that give rise to a time-dependent phase
path. The ULF electric and magnetic fields are calculated by a
one-dimensional model which calculates the wave propagation from the
magnetosphere, through the ionosphere to the ground with an oblique magnetic
field. These values are then used to determine a model HF Doppler shift which
is subsequently compared to HF Doppler observations. The ULF magnetic field
at the ground and Doppler observations are then used to provide model inputs
at various points throughout the event. We find evidence that the wave mode
evolved from a mixture of fast and Alfvén modes at the beginning of the
event to an almost purely shear Alfvénic mode after 6 wavecycles (33 min)
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A phenomenological investigation of the experience of taking part in 'Extreme Sports'
This article is concerned with what it may mean to individuals to engage in practices that are physically challenging and risky. The article questions the assumptions that psychological health is commensurate with maintaining physical safety, and that risking one's health and physical safety is necessarily a sign of psychopathology. The research was based upon semi-structured interviews with eight extreme sport practitioners. The interviews were analysed using Colaizzi's version of the phenomenological method. The article explicates the themes identified in the analysis, and discusses their implications for health psychology theory and practice
Concurrent extrahepatic autoimmunity in autoimmune hepatitis: implications for diagnosis, clinical course and long term outcome
Concurrent extrahepatic autoimmune disease (CEHAID) associated with autoimmune hepatitis (AIH) have been incorporated into the diagnostic criteria stipulated by the International Autoimmune Hepatitis Group (IAIHG). Large comprehensive cohort data on the extrahepatic autoimmunity in AIH remain scanty AIM: To systematically assess features and clinical impact of CEHAID on AIH METHODS: Clinical records of 562 patients with AIH from two tertiary centres in the United Kingdom were retrospectively reviewed RESULTS: Prevalence of CEHAID in patients with AIH were 42%. Autoimmune thyroid disease was the commonest CEHAID associated with AIH (101/562, 18%). Autoimmune skin diseases were more prevalent in AIH-2 than AIH-1 (21.9% vs.7%, p=0.009). Personal history of CEHAID was more commonly found in AIH patients with than without first degree family history of CEHAID [(48/86, 55.8% vs 169/446, 37.9%), p=0.002]. AIH patients with CEHAID were more often female [201/236 (85.2%), p=0.008], had higher post-treatment IAIHG score (22 vs. 20, p<0.001), less reactivity to smooth muscle antibodies (49.8% vs 65%, p<0.001), more likely to have mild fibrosis at diagnosis (20.9% vs. 6.5%, p<0.001), less often had ascites (6.3% vs. 13.6%, p=0.008) and coagulopathy (1.18 vs. 1.27, p=0.013) at presentation. Presence of CEHAID, however, did not significantly affect disease progression, prognosis and survival in AIH CONCLUSIONS: Our study confirms the strong association of CEHAID with AIH. Association between personal and familial extrahepatic autoimmunity especially among first degree relatives was evident. Presence of CEHAID may influence clinical phenotype of AIH at presentation but without notable impact on the long term clinical outcome
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