18,192 research outputs found
EUV Irradiance Observations from SDO/EVE as a Diagnostic of Solar Flares
For the past six years, the EUV Variability Experiment (EVE) onboard the
Solar Dynamics Observatory has been monitoring changes in the Sun's extreme
ultraviolet output over a range of timescales. Its primary function is to
provide measurements of the solar spectral irradiance that is responsible for
driving fluctuations in Earth's ionosphere and thermosphere. However, despite
its modest spectral resolution and lack of spatial information, the EVE
spectral range contains many lines and continua that have become invaluable for
diagnosing the response of the lower solar atmosphere itself to an injection of
energy, particularly during a flare's impulsive phase. In addition, high
temperature emission lines can also be used to track changes in temperature and
density of flaring plasma in the corona. The high precision of EVE observations
are therefore crucial in helping us understand particle acceleration and energy
transport mechanisms during solar flares, as well as the origins of the Sun's
most geoeffective emission.Comment: 10 pages, 7 figures. Submitted to conference proceedings for the
symposium on "Solar and Stellar Flares and their Effects on the Planets" at
the IAU General Assembly in Honolulu, HI, August 201
Sherley v. Sebelius: Stem Cells and the Uneasy Interplay Between the Federal Bench and the Lab Bench
After Barack Obama\u27s election to the presidency, he promised that one of his top priorities in office would be to relieve the restrictions initiated by President George W. Bush on federal funding of embryonic stem cell research. President Obama followed through on his promise, but the celebrations in the nation\u27s research labs were short-lived. Anti-abortion advocates and other scientists working in the field that would allegedly be out-competed in the federal funding arena brought a legal challenge to the new government position. The struggle culminated in August 2010 with a federal district court issuing a preliminary injunction to halt the new funding initiative. Although the government successfully appealed for a stay on the injunction pending arguments in the Court of Appeals, the decision has paralyzed research in the field. This iBrief argues that the injunction was wrongly granted, predicts how higher courts might treat the case, and suggests that the proper forum for addressing this controversy lies within the scientific community, not the judiciary
Rapists, Sexual Offenders, and Child Molesters: Who is Your Romantic Match ? Why Dating Websites Should Perform Criminal Background Checks
On the Performance of Multi-Instrument Solar Flare Observations During Solar Cycle 24
The current fleet of space-based solar observatories offers us a wealth of
opportunities to study solar flares over a range of wavelengths. Significant
advances in our understanding of flare physics often come from coordinated
observations between multiple instruments. Consequently, considerable efforts
have been, and continue to be made to coordinate observations among instruments
(e.g. through the Max Millennium Program of Solar Flare Research). However,
there has been no study to date that quantifies how many flares have been
observed by combinations of various instruments. Here we describe a technique
that retrospectively searches archival databases for flares jointly observed by
RHESSI, SDO/EVE (MEGS-A and -B), Hinode/(EIS, SOT, and XRT), and IRIS. Out of
the 6953 flares of GOES magnitude C1 or greater that we consider over the 6.5
years after the launch of SDO, 40 have been observed by six or more instruments
simultaneously. Using each instrument's individual rate of success in observing
flares, we show that the numbers of flares co-observed by three or more
instruments are higher than the number expected under the assumption that the
instruments operated independently of one another. In particular, the number of
flares observed by larger numbers of instruments is much higher than expected.
Our study illustrates that these missions often acted in cooperation, or at
least had aligned goals. We also provide details on an interactive widget now
available in SSWIDL that allows a user to search for flaring events that have
been observed by a chosen set of instruments. This provides access to a broader
range of events in order to answer specific science questions. The difficulty
in scheduling coordinated observations for solar-flare research is discussed
with respect to instruments projected to begin operations during Solar Cycle
25, such as DKIST, Solar Orbiter, and Parker Solar Probe.Comment: 26 pages, 7 figures, 3 tables. Accepted for publication in Solar
Physic
Continuum Contributions to the SDO/AIA Passbands During Solar Flares
Data from the Multiple EUV Grating Spectrograph (MEGS-A) component of the
Extreme Ultraviolet Experiment (EVE) onboard the Solar Dynamics Observatory
(SDO) were used to quantify the contribution of continuum emission to each of
the EUV channels of the Atmospheric Imaging Assembly (AIA), also on SDO, during
an X-class solar flare that occurred on 2011 February 15. Both the pre-flare
subtracted EVE spectra and fits to the associated free-free continuum were
convolved with the AIA response functions of the seven EUV passbands at 10 s
cadence throughout the course of the flare. It was found that 10-25% of the
total emission in the 94A, 131A, 193A, and 335A passbands throughout the main
phase of the flare was due to free-free emission. Reliable measurements could
not be made for the 171A channel, while the continuum contribution to the 304A
channel was negligible due to the presence of the strong He II emission line.
Up to 50% of the emission in the 211A channel was found to be due to free-free
emission around the peak of the flare, while an additional 20% was due to the
recombination continuum of He II. The analysis was extended to a number of M-
and X-class flares and it was found that the level of free-free emission
contributing to the 171A and 211A passbands increased with increasing GOES
class. These results suggest that the amount of continuum emission that
contributes to AIA observations during flares is more significant than that
stated in previous studies which used synthetic, rather than observed, spectra.
These findings highlight the importance of spectroscopic observations carried
out in conjunction with those from imaging instruments so that the data are
interpreted correctly.Comment: 9 pages, 6 figures, 1 tabl
Fair Is Fair—Reshaping Alaska’s Unfair Trade Practices and Consumer Protection Act
Few fields of law impact as wide a swath of population as consumer protection law. Alaska adopted its consumer protection statute, the Unfair Trade Practices and Consumer Protection Act (UTPCPA), amid a national movement to strengthen consumer protection laws. The UTPCPA uses broad language to encompass a wide range of conduct. However, creative pleading and recent applications of the UTPCPA have expanded the law in ways that threaten Alaska businesses even in the absence of culpable conduct. This Note reviews the history of consumer protection, Alaska’s UTPCPA, and the incentives leading to an expanding application of the UTPCPA. The Note concludes by proposing potential legislative solutions to rein in abuse of the Act
The Anomalous Temporal Behaviour of Broadband Ly Emission During Solar Flares From SDO/EVE
Despite being the most prominent emission line in the solar spectrum, there
has been a notable lack of studies devoted to variations in Ly emission
during solar flares in recent years. However, the few examples that do exist
have shown Ly emission to be a substantial radiator of the total energy
budget of solar flares (on the order of 10%). It is also a known driver of
fluctuations in earth's ionosphere. The EUV Variability Experiment (EVE)
onboard the Solar Dynamics Observatory now provides broadband, photometric
Ly data at 10 s cadence with its Multiple EUV Grating
Spectrograph-Photometer (MEGS-P) component, and has observed scores of solar
flares in the 5 years since it was launched. However, the MEGS-P time profiles
appear to display a rise time of tens of minutes around the time of the flare
onset. This is in stark contrast to the rapid, impulsive increase observed in
other intrinsically chromospheric features (H, Ly, LyC, C III,
etc.). Furthermore, the emission detected by MEGS-P peaks around the time of
the peak of thermal soft X-ray emission, rather than during the impulsive phase
when energy deposition in the chromosphere - often assumed to be in the form of
nonthermal electrons - is greatest. Given that spectrally-resolved Ly
observations during flares from SORCE/SOLSTICE peak during the impulsive phase
as expected, this suggests that the atypical behaviour of MEGS-P data is a
manifestation of the broadband nature of the observations. This could imply
that other lines and/or continuum emission that becomes enhanced during flares
could be contributing to the passband. Users are hereby urged to exercise
caution when interpreting broadband Ly observations of solar flares.
Comparisons have also been made with other broadband Ly photometers
such as PROBA2/LYRA and GOES/EUVS-E.Comment: Submitted to A&A Research Notes, 5 pages 4 figure
Decay Phase Cooling and Inferred Heating of M- and X-class Solar Flares
In this paper, the cooling of 72 M- and X-class flares is examined using
GOES/XRS and SDO/EVE. The observed cooling rates are quantified and the
observed total cooling times are compared to the predictions of an analytical
0-D hydrodynamic model. It is found that the model does not fit the
observations well, but does provide a well defined lower limit on a flare's
total cooling time. The discrepancy between observations and the model is then
assumed to be primarily due to heating during the decay phase. The decay phase
heating necessary to account for the discrepancy is quantified and found be
~50% of the total thermally radiated energy as calculated with GOES. This decay
phase heating is found to scale with the observed peak thermal energy. It is
predicted that approximating the total thermal energy from the peak is
minimally affected by the decay phase heating in small flares. However, in the
most energetic flares the decay phase heating inferred from the model can be
several times greater than the peak thermal energy.Comment: Published in the Astrophysical Journal, 201
Are We Practicing What We Are Taught in Health Professions’ Education? Coproducing Health Care
Health-care providers and educators are inherently empathetic, compassionate, experienced professionals who entered their profession to assure the complementary missions of public health and health care. These missions work to ensure conditions in which people can be healthy via disease and injury prevention, health promotion, and timely, effective, coordinated care (1). The skills necessary to achieve these crucial outcomes (ie, listening to the patient and their family, exhibiting empathy, and understanding the significance of the social determinants of health, etc) are routinely taught in health professions’ education.
To highlight the necessity for these representative competencies covered throughout the course of health professions’ education, the personal experience of one of the author’s children is reported as a narration. The purpose of communicating this patient experience is to remind health-care providers: (a) about the importance of not only listening but hearing the parents of our patients and the patients themselves, (b) to actively practice the art and skill of empathy as the health-care setting can be overwhelming for patients and their families, and (c) to consider the impact of the social determinants of health on one’s health status to date. This 5-part patient experience serves to strengthen our commitment to assure that we practice what we are taught with the goal to coproduce health with our patients and their families
Evaluation of a Pound Net Leader Designed to Reduce Sea Turtle Bycatch
Offshore pound net leaders in the southern portion of Chesapeake Bay in Virginia waters were documented to incidentally take protected loggerhead, Caretta caretta, and Kemp’s ridley, Lepidochelys kempii, sea turtles. Because of these losses, NOAA’s National Marine Fisheries Service (NMFS) in 2004 closed the area to offshore pound net leaders annually from 6 May to 15 July and initiated a study of an experimental leader design that replaced the top two-thirds of the traditional mesh panel leader with vertical ropes (0.95 cm) spaced 61 cm apart. This experimental leader was tested on four pound net sites on the eastern shore of Chesapeake Bay in 2004 and 2005. During the 2 trial periods, 21 loggerhead and Kemp’s ridley sea turtles were found interacting with the control leader and 1 leatherback turtle, Dermochelys coriacea, was found interacting with the experimental leader. Results of a negative binomial regression analysis comparing the two leader designs found the experimental leader significantly reduced sea turtle interactions (p=0.03).
Finfish were sampled from the pound nets in the study to assess finfish catch performance differences between the two leader designs. Although the conclusions from this element of the experiment are not robust, paired t-test and Wilcoxon signed rank test results determined no significant harvest weight difference between the two leaders. Kolmogorov-Smirnov tests did not reveal any substantive size selectivity differences between the two leaders
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