137 research outputs found
Flaring Rates and the Evolution of Sunspot Group McIntosh Classiļ¬cations
Sunspot groups are the main source of solar ļ¬ares, with the energy to power them being supplied by magnetic-ļ¬eld evolution (e.g. ļ¬ux emergence or twisting/shearing). To date, few studies have investigated the statistical relation between sunspot-group evolution and ļ¬aring, with none considering evolution in the McIntosh classiļ¬cation scheme. Here we present a statistical analysis of sunspot groups from Solar Cycle 22, focusing on 24-hour changes in the three McIntosh classiļ¬cation components. Evolution-dependent > C1.0, >M1.0, and > X1.0 ļ¬aring rates are calculated, leading to the following results: (i) ļ¬aring rates become increasingly higher for greater degrees of upward evolution through the McIntosh classes, with the opposite found for downward evolution; (ii) the highest ļ¬aring rates are found for upward evolution from larger, more complex, classes (e.g. Zurich D- and E-classes evolving upward to F-class produce > C1.0 rates of 2.66 Ā± 0.28 and 2.31 Ā± 0.09 ļ¬ares per 24 hours, respectively); (iii) increasingly complex classes give higher rates for all ļ¬are magnitudes, even when sunspot groups do not evolve over 24 hours. These results support the hypothesis that injection of magnetic energy by ļ¬ux emergence (i.e. increasing in Zurich or compactness classes) leads to a higher frequency and magnitude of ļ¬aring
Flare Forecasting Using the Evolution of McIntosh Sunspot Classifications
Most solar flares originate in sunspot groups, where magnetic field changes lead to energy build-up and release. However, few flare-forecasting methods use information of sunspot-group evolution, instead focusing on static point-in-time observations. Here, a new forecast method is presented based upon the 24-hr evolution in McIntosh classification of sunspot groups. Evolution-dependent >C1.0 and >M1.0 flaring rates are found from NOAA-numbered sunspot groups over December 1988 to June 1996 (Solar Cycle 22; SC22) before converting to probabilities assuming Poisson statistics. These flaring probabilities are used to generate operational forecasts for sunspot groups over July 1996 to December 2008 (SC23), with performance studied by verification metrics. Major findings are: i) considering Brier skill score (BSS) for >C1.0 flares, the evolution-dependent McIntosh-Poisson method BSS_evolution=0.09 performs better than the static McIntosh-Poisson method BSS_static= -0.09; ii) low BSS values arise partly from both methods over-forecasting SC23 flares from the SC22 rates, symptomatic of >C1.0 rates in SC23 being on average 80% of those in SC22 (with >M1.0 being approx 50%); iii) applying a bias-correction factor to reduce the SC22 rates used in forecasting SC23 flares yields modest improvement in skill relative to climatology for both methods BSS_corr_static = 0.09$ and BSS_corr_evolution = 0.20) and improved forecast reliability diagrams
Flare Forecasting Using the Evolution of McIntosh Sunspot Classifications
Most solar flares originate in sunspot groups, where magnetic field changes
lead to energy build-up and release. However, few flare-forecasting methods use
information of sunspot-group evolution, instead focusing on static
point-in-time observations. Here, a new forecast method is presented based upon
the 24-hr evolution in McIntosh classification of sunspot groups.
Evolution-dependent C1.0 and M1.0 flaring rates are found
from NOAA-numbered sunspot groups over December 1988 to June 1996 (Solar Cycle
22; SC22) before converting to probabilities assuming Poisson statistics. These
flaring probabilities are used to generate operational forecasts for sunspot
groups over July 1996 to December 2008 (SC23), with performance studied by
verification metrics. Major findings are: i) considering Brier skill score
(BSS) for C1.0 flares, the evolution-dependent McIntosh-Poisson
method () performs better than the static
McIntosh-Poisson method (); ii) low BSS
values arise partly from both methods over-forecasting SC23 flares from the
SC22 rates, symptomatic of C1.0 rates in SC23 being on average
80% of those in SC22 (with M1.0 being 50%); iii)
applying a bias-correction factor to reduce the SC22 rates used in forecasting
SC23 flares yields modest improvement in skill relative to climatology for both
methods ( and
) and improved
forecast reliability diagrams.Comment: 21 pages, 9 figure
Assistive technologies, educational engagement and psychosocial outcomes among students with disabilities in higher education
Purpose: Increasing numbers of students with disabilities are accessing higher education each year, yet little is known about their assistive technology (AT) needs and its influence on relevant outcomes. The aim of this study was to examine met/unmet AT needs on educational engagement, academic self-efficacy and well-being and the impact of AT use in the areas of competence, adaptability and self-esteem for students with disabilities in higher education in Ireland.
Methods: 111 students with disabilities completed a cross-sectional online survey comprising the College Learning Effectiveness Inventory, the Student Course Engagement Questionnaire, the Self-Efficacy for Learning Form Abridged, the Psychosocial Impact of Assistive Devices Scale, and the Warwick-Edinburgh Mental Well-Being Scale.
Results: AT use was found to have a positive psychosocial impact in the areas of competence, adaptability and self-esteem. Those whose AT needs were fully met scored significantly higher on academic self-efficacy, well-being, and on 4 of the 10 educational engagement subscales compared to those who had unmet AT needs. Met/unmet AT needs were not predictive of educational engagement.
Conclusion: These findings highlight the importance of AT from both educational engagement and psychosocial perspectives for students with a wide variety of disability diagnoses. The wide-reaching benefits of AT must be considered by governmental departments when making funding allocations to disability services within higher education institutions
Feeling valued: the interplay of assistive technology and identity
Purpose: The aim of this study was to explore the impact of AT in identity for students with disabilities in higher education and if/how this changes over time.
Methods: Using a longitudinal qualitative research design, semi-structured interviews were conducted with students with disabilities (n=13) in higher education in Ireland on two occasions during an academic year. A trajectory approach to longitudinal analysis was employed. This involved the use of matrices and identification of a through line for the study, which connects participant change over time.
Results: The through line identified was feeling valued, which was central in the negotiation of identity over time across three themes: feelings of autonomy and competence; claiming disability; and feeling like you belong as a student. AT impacted experiences across the three themes which subsequently promoted or undermined studentsā sense of value. Reciprocally, feeling valued influenced use and perceptions of AT. Factors specific to a higher education context were also identified which influenced meanings attached to AT over time.
Conclusion: Creating an environment where students feel valued is key in promoting use of and positive perceptions of AT. This should form an integral part of AT and disability policy in higher education
LOFAR observations of radio burst source sizes and scattering in the solar corona
Low frequency radio wave scattering and refraction can have a dramatic effect
on the observed size and position of radio sources in the solar corona. The
scattering and refraction is thought to be due to fluctuations in electron
density caused by turbulence. Hence, determining the true radio source size can
provide information on the turbulence in coronal plasma. However, the lack of
high spatial resolution radio interferometric observations at low frequencies,
such as with the LOw Frequency ARray (LOFAR), has made it difficult to
determine the true radio source size and level of radio wave scattering. Here
we directly fit the visibilities of a LOFAR observation of a Type IIIb radio
burst with an elliptical Gaussian to determine its source size and position.
This circumvents the need to image the source and then de-convolve LOFAR's
point spread function, which can introduce spurious effects to the source size
and shape. For a burst at 34.76 MHz, we find full width at half maximum (FWHM)
heights along the major and minor axes to be and
, respectively, at a plane of sky heliocentric
distance of 1.75 R. Our results suggest that the level of density
fluctuations in the solar corona is the main cause of the scattering of radio
waves, resulting in large source sizes. However, the magnitude of
may be smaller than what has been previously derived in observations of radio
wave scattering in tied-array images.Comment: 6 pages, 3 figures, accepted for publication in Astronomy &
Astrophysic
The impact of assistive technology use for students with disabilities in higher education: a systematic review
Purpose: This systematic review examines the impact of assistive technology (AT) on educational and psychosocial outcomes for students with disabilities (SWD) in higher education.
Materials and methods: Qualitative, quantitative and mixed method studies were identified through systematic searches of five databases: PsycINFO, PubMed, CINAHL, ERIC and Web of Science (Social Science Citation Index). Thematic synthesis was carried out to collate findings across papers and the methodological quality of included papers was assessed using a mixed methods appraisal tool.
Results: Twenty six papers were included for analysis. Four analytic themes were identified; āAT as an enabler of academic engagementā; ābarriers to effective AT use can hinder academic engagementā; āthe transformative possibilities of AT from a psychological perspectiveā; āAT as an enabler of participationā.
Conclusions: This systematic review demonstrates that AT can promote educational, psychological and social benefits for SWD. However, AT users and AT officers must be aware of certain factors that can hinder effective AT use and thus restrict engagement in the higher education environment. Future AT practices should focus on harnessing the potential of mainstream devices as AT for all students, thus facilitating inclusion and reducing stigma
Anakinra for recalcitrant pyoderma gangrenosum
Pyoderma gangrenosum (PG) is an autoinflammatory neutrophilic dermatosis characterized by rapidly enlarging, painful ulcers. Anakinra is a recombinant interleukin-1 (IL-1) receptor antagonist that blocks the activity of IL-1Ī± and IL-1Ī² by competitively inhibiting IL-1 binding to the IL-1 type I receptor. We present a series of two patients with recalcitrant PG, who had limited therapeutic options due to multiple previous treatment failures and multiple co-morbidities, who obtained 100% healing with anakinra. Compared to conventional first-line therapies for PG, the safety profile of anakinra may be preferable for patients with multiple co-morbidities. Further research is needed to assess the safety and efficacy of anakinra for PG
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