356 research outputs found
LEARNS: A creative approach to analysing and representing narrative data incorporating photo-elicitation techniques
© 2018, The Author(s) 2018. Background: Diversity exists in how storied data gathered in narrative inquiry is analysed and represented, more so when there is a need to combine multiple data collection methods, including photographs. Aim: This paper discusses the use of an analytical framework entitled LEARNS developed as part of a PhD study that has potential to fill this gap. Results: The step-by-step framework presented in this paper was developed in order to analyse the data collected in this research study and gives understanding and insight into the experience of mothers whose babies are removed at birth. The LEARNS framework provides transparency and credibility; it also negates the need to restrict findings to broad themes via content/thematic analysis. Conclusions: LEARNS could offer other researchers a reliable framework to use for future social science research
The Whole Heliosphere Interval in the Context of a Long and Structured Solar Minimum: An Overview from Sun to Earth
Throughout months of extremely low solar activity during the recent extended solar-cycle minimum, structural evolution continued to be observed from the Sun through the solar wind and to the Earth. In 2008, the presence of long-lived and large low-latitude coronal holes meant that geospace was periodically impacted by high-speed streams, even though solar irradiance, activity, and interplanetary magnetic fields had reached levels as low as, or lower than, observed in past minima. This time period, which includes the first Whole Heliosphere Interval (WHI 1: Carrington Rotation (CR) 2068), illustrates the effects of fast solar-wind streams on the Earth in an otherwise quiet heliosphere. By the end of 2008, sunspots and solar irradiance had reached their lowest levels for this minimum (e.g., WHI 2: CR 2078), and continued solar magnetic-flux evolution had led to a flattening of the heliospheric current sheet and the decay of the low-latitude coronal holes and associated Earth-intersecting high-speed solar-wind streams. As the new solar cycle slowly began, solar-wind and geospace observables stayed low or continued to decline, reaching very low levels by June – July 2009. At this point (e.g., WHI 3: CR 2085) the Sun–Earth system, taken as a whole, was at its quietest. In this article we present an overview of observations that span the period 2008 – 2009, with highlighted discussion of CRs 2068, 2078, and 2085. We show side-by-side observables from the Sun’s interior through its surface and atmosphere, through the solar wind and heliosphere and to the Earth’s space environment and upper atmosphere, and reference detailed studies of these various regimes within this topical issue and elsewhere
A Model of Turbulence in Magnetized Plasmas: Implications for the Dissipation Range in the Solar Wind
This paper studies the turbulent cascade of magnetic energy in weakly
collisional magnetized plasmas. A cascade model is presented, based on the
assumptions of local nonlinear energy transfer in wavenumber space, critical
balance between linear propagation and nonlinear interaction times, and the
applicability of linear dissipation rates for the nonlinearly turbulent plasma.
The model follows the nonlinear cascade of energy from the driving scale in the
MHD regime, through the transition at the ion Larmor radius into the kinetic
Alfven wave regime, in which the turbulence is dissipated by kinetic processes.
The turbulent fluctuations remain at frequencies below the ion cyclotron
frequency due to the strong anisotropy of the turbulent fluctuations,
k_parallel << k_perp (implied by critical balance). In this limit, the
turbulence is optimally described by gyrokinetics; it is shown that the
gyrokinetic approximation is well satisfied for typical slow solar wind
parameters. Wave phase velocity measurements are consistent with a kinetic
Alfven wave cascade and not the onset of ion cyclotron damping. The conditions
under which the gyrokinetic cascade reaches the ion cyclotron frequency are
established. Cascade model solutions imply that collisionless damping provides
a natural explanation for the observed range of spectral indices in the
dissipation range of the solar wind. The dissipation range spectrum is
predicted to be an exponential fall off; the power-law behavior apparent in
observations may be an artifact of limited instrumental sensitivity. The
cascade model is motivated by a programme of gyrokinetic simulations of
turbulence and particle heating in the solar wind.Comment: 29 pages, 14 figure
A Mixed-Methods Evaluation of a Community-Based Glaucoma Check Service in Hackney, London, UK.
: To evaluate the uptake, feasibility and acceptability of a general practice-based optometrist-led glaucoma check service. The service targeted people of black Caribbean and black African descent aged 40-65 years, resident in Hackney, London, United Kingdom. : The study used a mixed-method design, including analysis of service data, prospective audit of secondary care referrals patient survey, cost-consequence analysis, and interviews with staff involved in developing and implementing the service. : A total of 3040 patients were invited to undergo the free check; 595 (19.6%) booked an appointment and 461 (15.2%) attended. Overall, 31 patients (6.8%) were referred to secondary care, of whom 22 attended and were assessed for glaucoma. Four were diagnosed with glaucoma and eight with suspected glaucoma, i.e. 2.6% of patients who underwent the check. The cost per patient identified with suspected or confirmed glaucoma was £9,013. Staff who were interviewed suggested that patients who attended might be those who routinely attended optometrist appointments, however only 62.4% of survey respondents reported having had an eye examination in the previous two years, and 11.4% of women and 16.0% of men reported never having had an eye examination. : This study represents one possible configuration for a glaucoma case-finding service, and it contributes to a wider debate about whether screening, targeted or otherwise, should be offered in the UK. Our findings suggest that general practice is an acceptable setting and that such a service may reach some people not previously engaged with primary eye care services.<br/
Treatment of experimental adjuvant arthritis with a novel folate receptor-targeted folic acid-aminopterin conjugate
Introduction
Folate receptor (FR)-expressing macrophages have been shown to accumulate at sites of inflammation, where they promote development of inflammatory symptoms. To target such a macrophage population, we designed and evaluated the biologic activity of EC0746, a novel folic acid conjugate of the highly potent antifolate, aminopterin. Methods
Using a FR-positive subclone of murine macrophage-derived RAW264.7 cells and rat thioglycollate-elicited macrophages, we studied the effect of EC0746 on dihydrofolate reductase activity, cell proliferation, and cellular response towards bacterial lipopolysaccharide as well as IFNγ activation. The EC0746 anti-inflammatory activity, pharmacokinetics, and toxicity were also evaluated in normal rats or in rats with adjuvant-induced arthritis; that is, a FR-positive macrophage model that closely resembles rheumatoid arthritis in humans. Results
EC0746 suppresses the proliferation of RAW264.7 cells and prevents the ability of nonproliferating rat macrophages to respond to inflammatory stimuli. In the macrophage-rich rat arthritis model, brief treatment with subcutaneously administered EC0746 is shown to mediate an FR-specific anti-inflammatory response that is more potent than either orally administered methotrexate or subcutaneously delivered etanercept. More importantly, EC0746 therapy is also shown to be ~40-fold less toxic than unmodified aminopterin, with fewer bone marrow and gastrointestinal problems. Conclusions
EC0746 is the first high FR-binding dihydrofolate reductase inhibitor that demonstrates FR-specific anti-inflammatory activities both in vitro and in vivo. Our data reveal that a relatively toxic anti-inflammatory drug, such as aminopterin, can be targeted with folic acid to inflammatory macrophages and thereby relieve inflammatory symptoms with greatly reduced toxicity
The Post-Eruptive Evolution of a Coronal Dimming
We discuss the post-eruptive evolution of a "coronal dimming" based on
observations of the EUV corona from the Solar and Heliospheric Observatory and
the Transition Region and Coronal Explorer. This discussion highlights the
roles played by magnetoconvection-driven magnetic reconnection and the global
magnetic environment of the plasma in the "filling" and apparent motion of the
region following the eruption of a coronal mass ejection (CME). A crucial
element in our understanding of the dimming region evolution is developed by
monitoring the disappearance and reappearance of bright TRACE "moss" around the
active region giving rise to the CME. We interpret the change in the TRACE moss
as a proxy of the changing coronal magnetic field topology behind the CME
front. We infer that the change in global magnetic topology also results in a
shift of energy balance in the process responsible for the production of the
moss emission while the coronal magnetic topology evolves from closed, to open
and back to closed again because, following the eruption, the moss reforms
around the active region in almost exactly its pre-event configuration. As a
result of the moss evolution, combining our discussion with recent
spectroscopic results of an equatorial coronal hole, we suggest that the
interchangeable use of the term "transient coronal hole" to describe a coronal
dimming is more than just a simple coincidence.Comment: In Press ApJ [May 2007] - 15 pages, 5 figures, 7 movies that are
available upon request [contact author
What is the role of the kink instability in solar coronal eruptions
ABSTRACT We report the results of two simple studies which seek observational evidence that solar coronal loops are unstable to the MHD kink instability above a certain critical value of the total twist. First, we have used Yohkoh SXT image sequences to measure the shapes of 191 X-ray sigmoids and to determine the histories of eruption (evidenced by cusp and arcade signatures) of their associated active regions. We find that the distribution of sigmoid shapes is quite narrow and the frequency of eruption does not depend significantly on shape. Second, we have used Mees Solar Observatory vector magnetograms to estimate the largescale total twist of active regions in which flare-related signatures of eruption are observed. We find no evidence of eruption for values of large-scale total twist remotely approaching the threshold for the kink instability
Coronal electron temperature in the protracted solar minimum, the cycle 24 mini maximum, and over centuries
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/106800/1/jgra50869.pd
Statistical anisotropy of magnetohydrodynamic turbulence
Direct numerical simulations of decaying and forced magnetohydrodynamic (MHD)
turbulence without and with mean magnetic field are analyzed by higher-order
two-point statistics. The turbulence exhibits statistical anisotropy with
respect to the direction of the local magnetic field even in the case of global
isotropy. A mean magnetic field reduces the parallel-field dynamics while in
the perpendicular direction a gradual transition towards two-dimensional MHD
turbulence is observed with inertial-range scaling of the
perpendicular energy spectrum. An intermittency model based on the Log-Poisson
approach, , is able to describe the observed
structure function scalings.Comment: 4 pages, 3 figures. To appear in Phys.Rev.
The Impact of New EUV Diagnostics on CME-Related Kinematics
We present the application of novel diagnostics to the spectroscopic
observation of a Coronal Mass Ejection (CME) on disk by the Extreme Ultraviolet
Imaging Spectrometer (EIS) on the Hinode spacecraft. We apply a recently
developed line profile asymmetry analysis to the spectroscopic observation of
NOAA AR 10930 on 14-15 December 2006 to three raster observations before and
during the eruption of a 1000km/s CME. We see the impact that the observer's
line-of-sight and magnetic field geometry have on the diagnostics used.
Further, and more importantly, we identify the on-disk signature of a
high-speed outflow behind the CME in the dimming region arising as a result of
the eruption. Supported by recent coronal observations of the STEREO
spacecraft, we speculate about the momentum flux resulting from this outflow as
a secondary momentum source to the CME. The results presented highlight the
importance of spectroscopic measurements in relation to CME kinematics, and the
need for full-disk synoptic spectroscopic observations of the coronal and
chromospheric plasmas to capture the signature of such explosive energy release
as a way of providing better constraints of CME propagation times to L1, or any
other point of interest in the heliosphere.Comment: Accepted to appear in Solar Physics Topical Issue titled "Remote
Sensing of the Inner Heliosphere". Manuscript has 14 pages, 5 color figures.
Movies supporting the figures can be found in
http://download.hao.ucar.edu/pub/mscott/papers/Weathe
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