759 research outputs found
Ultraviolet spectroscopy of narrow coronal mass ejections
We present Ultraviolet Coronagraph Spectrometer (UVCS) observations of 5
narrow coronal mass ejections (CMEs) that were among 15 narrow CMEs originally
selected by Gilbert et al. (2001). Two events (1999 March 27, April 15) were
"structured", i.e. in white light data they exhibited well defined interior
features, and three (1999 May 9, May 21, June 3) were "unstructured", i.e.
appeared featureless. In UVCS data the events were seen as 4-13 deg wide
enhancements of the strongest coronal lines HI Ly-alpha and OVI (1032,1037 A).
We derived electron densities for several of the events from the Large Angle
Spectrometric Coronagraph (LASCO) C2 white light observations. They are
comparable to or smaller than densities inferred for other CMEs. We modeled the
observable properties of examples of the structured (1999 April 15) and
unstructured (1999 May 9) narrow CMEs at different heights in the corona
between 1.5 and 2 R(Sun). The derived electron temperatures, densities and
outflow speeds are similar for those two types of ejections. They were compared
with properties of polar coronal jets and other CMEs. We discuss different
scenarios of narrow CME formation either as a jet formed by reconnection onto
open field lines or CME ejected by expansion of closed field structures.
Overall, we conclude that the existing observations do not definitively place
the narrow CMEs into the jet or the CME picture, but the acceleration of the
1999 April 15 event resembles acceleration seen in many CMEs, rather than
constant speeds or deceleration observed in jets.Comment: AASTeX, 22 pages, incl. 3 figures (2 color) and 3 tables. Accepted
for publication in Ap.
STEREO Space Weather and the Space Weather Beacon
The Solar Terrestrial Relations Observatory (STEREO) is first and foremost a solar and interplanetary research mission, with one of the natural applications being in the area of space weather. The obvious potential for space weather applications is so great that NOAA has worked to incorporate the real-time data into their forecast center as much as possible. A subset of the STEREO data will be continuously downlinked in a real-time broadcast mode, called the Space Weather Beacon. Within the research community there has been considerable interest in conducting space weather related research with STEREO. Some of this research is geared towards making an immediate impact while other work is still very much in the research domain. There are many areas where STEREO might contribute and we cannot predict where all the successes will come. Here we discuss how STEREO will contribute to space weather and many of the specific research projects proposed to address STEREO space weather issues. We also discuss some specific uses of the STEREO data in the NOAA Space Environment Center
The hard X-ray burst spectrometer event listing 1980-1987
This event listing is a comprehensive reference for the Hard X-ray bursts detected with the Hard X-ray Burst Spectrometer on the Solar Maximum Mission from the time of launch 14 February 1980 to December 1987. Over 8600 X-ray events were detected in the energy range from 30 to approx. 600 keV with the vast majority being solar flares. The listing includes the start time, peak time, duration and peak rate of each event
Deceleration and Dispersion of Large-scale Coronal Bright Fronts
One of the most dramatic manifestations of solar activity are large-scale
coronal bright fronts (CBFs) observed in extreme ultraviolet (EUV) images of
the solar atmosphere. To date, the energetics and kinematics of CBFs remain
poorly understood, due to the low image cadence and sensitivity of previous EUV
imagers and the limited methods used to extract the features. In this paper,
the trajectory and morphology of CBFs was determined in order to investigate
the varying properties of a sample of CBFs, including their kinematics and
pulse shape, dispersion, and dissipation. We have developed a semi-automatic
intensity profiling technique to extract the morphology and accurate positions
of CBFs in 2.5-10 min cadence images from STEREO/EUVI. The technique was
applied to sequences of 171A and 195A images from STEREO/EUVI in order to
measure the wave properties of four separate CBF events. Following launch at
velocities of ~240-450kms^{-1} each of the four events studied showed
significant negative acceleration ranging from ~ -290 to -60ms^{-2}. The CBF
spatial and temporal widths were found to increase from ~50 Mm to ~200 Mm and
~100 s to ~1500 s respectively, suggesting that they are dispersive in nature.
The variation in position-angle averaged pulse-integrated intensity with
propagation shows no clear trend across the four events studied. These results
are most consistent with CBFs being dispersive magnetoacoustic waves.Comment: 15 pages, 18 figure
Spectroscopic analysis of interaction between an EIT wave and a coronal upflow region
We report a spectroscopic analysis of an EIT wave event that occurred in
active region 11081 on 2010 June 12 and was associated with an M2.0 class
flare. The wave propagated near circularly. The south-eastern part of the wave
front passed over an upflow region nearby a magnetic bipole. Using EIS raster
observations for this region, we studied the properties of plasma dynamics in
the wave front, as well as the interaction between the wave and the upflow
region. We found a weak blueshift for the Fe XII {\lambda}195.12 and Fe XIII
{\lambda}202.04 lines in the wave front. The local velocity along the solar
surface, which is deduced from the line of sight velocity in the wave front and
the projection effect, is much lower than the typical propagation speed of the
wave. A more interesting finding is that the upflow and non-thermal velocities
in the upflow region are suddenly diminished after the transit of the wave
front. This implies a significant change of magnetic field orientation when the
wave passed. As the lines in the upflow region are redirected, the velocity
along the line of sight is diminished as a result. We suggest that this
scenario is more in accordance with what was proposed in the field-line
stretching model of EIT waves.Comment: 13 pages, 7 figures, accepted for publication in Ap
Psychological Outcomes in Advanced Cancer Patients After Receiving Genomic Tumor Profiling Results
Background: Comprehensive tumor genomic profiling (CGP) offers hope for personalized treatment for cancer patients when other treatment options have been exhausted. However, receipt of nonactionable or ambiguous results could be an ongoing source of distress. We investigated patterns of hope, anxiety, depression, and CGP-specific anxiety in advanced cancer patients after receiving CGP results and 2–3 months later. Method: Participants were enrolled in a longitudinal psychosocial substudy, embedded in the Molecular Screening and Therapeutics Program, and had advanced solid cancers of any histological type with sufficient and accessible tissue for CGP. At T0 (before receiving CGP results), 1,431 participants completed sociodemographic, disease and psychosocial measures. At T1 (1–4 weeks after receiving CGP results) and T2 (2–3 months post-T1), 374 participants completed psychological outcome measures. Predictors of outcomes at T2 were identified using multinomial logistic regression. Results: Approximately 75% of participants did not experience significant hopelessness or distress at T1 and T2. Hope decreased by T2, yet general anxiety and CGP-specific anxiety also decreased. Receiving actionable results did not impact psychological outcomes at T2. At T2, lower hope, and higher anxiety, depression and CGP-specific anxiety were associated with lower self-efficacy. Psychological and demographic factors (age, socioeconomic status, language, medical occupation, urban living, family history of cancer) independently predicted one or more psychological trajectories. Worse health status and perceived susceptibility to cancer progression predicted hope and anxiety trajectories. Conclusion: Further research on interventions to best support patients undergoing CGP with high anxiety, hopelessness, fear of cancer progression, and poorer health is urgently needed
From Predicting Solar Activity to Forecasting Space Weather: Practical Examples of Research-to-Operations and Operations-to-Research
The successful transition of research to operations (R2O) and operations to
research (O2R) requires, above all, interaction between the two communities. We
explore the role that close interaction and ongoing communication played in the
successful fielding of three separate developments: an observation platform, a
numerical model, and a visualization and specification tool. Additionally, we
will examine how these three pieces came together to revolutionize
interplanetary coronal mass ejection (ICME) arrival forecasts. A discussion of
the importance of education and training in ensuring a positive outcome from
R2O activity follows. We describe efforts by the meteorological community to
make research results more accessible to forecasters and the applicability of
these efforts to the transfer of space-weather research.We end with a
forecaster "wish list" for R2O transitions. Ongoing, two-way communication
between the research and operations communities is the thread connecting it
all.Comment: 18 pages, 3 figures, Solar Physics in pres
Psychological impact of comprehensive tumor genomic profiling results for advanced cancer patients
Objective: Comprehensive tumor genomic profiling (CTGP) is increasingly used to personalize treatments, providing hope, but potentially disappointment, for patients. We explored psychological outcomes in patients with advanced, incurable cancer, after receiving CTGP results. Methods: Participants with advanced, incurable cancer (n = 560, mean age 56, 43% university educated) in this longitudinal substudy of the Molecular Screening and Therapeutics Program (MoST), completed questionnaires before and after receiving CGP results. MoST participants, recruited from Australian oncology clinics, undergo CTGP, and if there are actionable findings, are offered treatment in a related therapeutic trial if available. Results: Patients who received actionable results, (n = 356, 64%) had lower gene-related distress (MICRA) (p < 0.001) and Impact of Events scores (p = 0.039) than patients with non-actionable results. Those with actionable results offered ensured access to tailored treatment (n = 151) reported lower anxiety (p = 0.002) and depressive symptoms (p = 0.01) and greater hope (p = 0.002) than those not offered. Positive attitudes towards uncertainty and higher self-efficacy for coping with results were associated with lower psychological distress and uncertainty, and higher hope and satisfaction with the decision to have CTGP (ps=0.001–0.047). Those with higher knowledge reported greater anxiety (p = 0.034). Conclusion: Receiving a non-actionable CTGP result, or an actionable result without ensured access to treatment, may cause increased distress in advanced cancer patients. Coping style was also associated with distress. Practice implications: Pre-testing assessment and counseling addressing attitudes toward uncertainty and self-efficacy, and post-CTGP result support for patients receiving a non-actionable result or who receive an actionable results without ensured access to treatment, may benefit patients
Numerical Simulation of an EUV Coronal Wave Based on the February 13, 2009 CME Event Observed by STEREO
On 13 February 2009, a coronal wave -- CME -- dimming event was observed in
quadrature by the STEREO spacecraft. We analyze this event using a
three-dimensional, global magnetohydrodynamic (MHD) model for the solar corona.
The numerical simulation is driven and constrained by the observations, and
indicates where magnetic reconnection occurs between the expanding CME core and
surrounding environment. We focus primarily on the lower corona, extending out
to ; this range allows simultaneous comparison with both EUVI and
COR1 data. Our simulation produces a diffuse coronal bright front remarkably
similar to that observed by STEREO/EUVI at 195 \AA. It is made up of \emph{two}
components, and is the result of a combination of both wave and non-wave
mechanisms.
The CME becomes large-scale quite low ( 200 Mm) in the corona. It is not,
however, an inherently large-scale event; rather, the expansion is facilitated
by magnetic reconnection between the expanding CME core and the surrounding
magnetic environment. In support of this, we also find numerous secondary
dimmings, many far from the initial CME source region. Relating such dimmings
to reconnecting field lines within the simulation provides further evidence
that CME expansion leads to the "opening" of coronal field lines on a global
scale. Throughout the CME expansion, the coronal wave maps directly to the CME
footprint.
Our results suggest that the ongoing debate over the "true" nature of diffuse
coronal waves may be mischaracterized. It appears that \emph{both} wave and
non-wave models are required to explain the observations and understand the
complex nature of these events
The PiGeOn project: Protocol for a longitudinal study examining psychosocial, behavioural and ethical issues and outcomes in cancer tumour genomic profiling
© 2018 The Author(s). Background: Genomic sequencing in cancer (both tumour and germline), and development of therapies targeted to tumour genetic status, hold great promise for improvement of patient outcomes. However, the imminent introduction of genomics into clinical practice calls for better understanding of how patients value, experience, and cope with this novel technology and its often complex results. Here we describe a protocol for a novel mixed-methods, prospective study (PiGeOn) that aims to examine patients' psychosocial, cognitive, affective and behavioural responses to tumour genomic profiling and to integrate a parallel critical ethical analysis of returning results. Methods: This is a cohort sub-study of a parent tumour genomic profiling programme enrolling patients with advanced cancer. One thousand patients will be recruited for the parent study in Sydney, Australia from 2016 to 2019. They will be asked to complete surveys at baseline, three, and fivemonths. Primary outcomes are: knowledge, preferences, attitudes and values. A purposively sampled subset of patients will be asked to participate in three semi-structured interviews (at each time point) to provide deeper data interpretation. Relevant ethical themes will be critically analysed to iteratively develop or refine normative ethical concepts or frameworks currently used in the return of genetic information. Discussion: This will be the first Australian study to collect longitudinal data on cancer patients' experience of tumour genomic profiling. Findings will be used to inform ongoing ethical debates on issues such as how to effectively obtain informed consent for genomic profiling return results, distinguish between research and clinical practice and manage patient expectations. The combination of quantitative and qualitative methods will provide comprehensive and critical data on how patients cope with 'actionable' and 'non-actionable' results. This information is needed to ensure that when tumour genomic profiling becomes part of routine clinical care, ethical considerations are embedded, and patients are adequately prepared and supported during and after receiving results
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