6,485 research outputs found
Faculty Turnover at American Colleges and Universities: Analyses of AAUP Data
This paper uses institutional level data collected by the American Association of University Professors as part of their annual survey of faculty members\u27 compensation to analyze faculty turnover. Analyses of aggregate data over almost a twenty-year period highlight how remarkably stable faculty retention rates have been nationwide and how little they vary across broad categories of institutions. Analyses of variations in faculty retention rates across individual institutions stress the role that faculty compensation levels play. Higher levels of compensation appear to increase retention rates for assistant and associate professors (but not for full professors) and the magnitude of this effect grows larger as one moves from institutions with graduate programs, to four-year undergraduate institutions, to two-year institutions
Nature of stochastic ion heating in the solar wind: testing the dependence on plasma beta and turbulence amplitude
The solar wind undergoes significant heating as it propagates away from the
Sun; the exact mechanisms responsible for this heating are not yet fully
understood. We present for the first time a statistical test for one of the
proposed mechanisms, stochastic ion heating. We use the amplitude of magnetic
field fluctuations near the proton gyroscale as a proxy for the ratio of
gyroscale velocity fluctuations to perpendicular (with respect to the magnetic
field) proton thermal speed, defined as . Enhanced proton
temperatures are observed when is larger than a critical value
(). This enhancement strongly depends on the proton plasma
beta (); when only the perpendicular proton
temperature increases, while for increased
parallel and perpendicular proton temperatures are both observed. For
smaller than the critical value and no
enhancement of is observed while for minor increases
in are measured. The observed change of proton temperatures
across a critical threshold for velocity fluctuations is in agreement with the
stochastic ion heating model of Chandran et al. (2010). We find that
in 76\% of the studied periods implying that
stochastic heating may operate most of the time in the solar wind at 1 AU.Comment: Accepted for publication in The Astrophysical Journal Letter
Magnetic Reconnection May Control the Ion-Scale Spectral Break of Solar Wind Turbulence
The power spectral density of magnetic fluctuations in the solar wind
exhibits several power-law-like frequency ranges with a well defined break
between approximately 0.1 and 1 Hz in the spacecraft frame. The exact
dependence of this break scale on solar wind parameters has been extensively
studied but is not yet fully understood. Recent studies have suggested that
reconnection may induce a break in the spectrum at a "disruption scale"
, which may be larger than the fundamental ion kinetic scales,
producing an unusually steep spectrum just below the break. We present a
statistical investigation of the dependence of the break scale on the proton
gyroradius , ion inertial length , ion sound radius ,
proton-cyclotron resonance scale and disruption scale as a
function of . We find that the steepest spectral indices of
the dissipation range occur when is in the range of 0.1-1 and the
break scale is only slightly larger than the ion sound scale (a situation
occurring 41% of the time at 1 AU), in qualitative agreement with the
reconnection model. In this range the break scale shows remarkably good
correlation with . Our findings suggest that, at least at low
, reconnection may play an important role in the development of the
dissipation range turbulent cascade and causes unusually steep (steeper than
-3) spectral indices.Comment: Accepted in ApJ
Magnetic fluctuation power near proton temperature anisotropy instability thresholds in the solar wind
The proton temperature anisotropy in the solar wind is known to be
constrained by the theoretical thresholds for pressure anisotropy-driven
instabilities. Here we use approximately 1 million independent measurements of
gyroscale magnetic fluctuations in the solar wind to show for the first time
that these fluctuations are enhanced along the temperature anisotropy
thresholds of the mirror, proton oblique firehose, and ion cyclotron
instabilities. In addition, the measured magnetic compressibility is enhanced
at high plasma beta () along the mirror instability
threshold but small elsewhere, consistent with expectations of the mirror mode.
The power in this frequency (the 'dissipation') range is often considered to be
driven by the solar wind turbulent cascade, an interpretation which should be
qualified in light of the present results. In particular, we show that the
short wavelength magnetic fluctuation power is a strong function of
collisionality, which relaxes the temperature anisotropy away from the
instability conditions and reduces correspondingly the fluctuation power.Comment: 4 pages, 4 figure
Predictions for the First Parker Solar Probe Encounter
We examine Alfv\'en Wave Solar atmosphere Model (AWSoM) predictions of the
first Parker Solar Probe (PSP) encounter. We focus on the 12-day closest
approach centered on the 1st perihelion. AWSoM (van der Holst et al., 2014)
allows us to interpret the PSP data in the context of coronal heating via
Alfv\'en wave turbulence. The coronal heating and acceleration is addressed via
outward-propagating low-frequency Alfv\'en waves that are partially reflected
by Alfv\'en speed gradients. The nonlinear interaction of these
counter-propagating waves results in a turbulent energy cascade. To apportion
the wave dissipation to the electron and anisotropic proton temperatures, we
employ the results of the theories of linear wave damping and nonlinear
stochastic heating as described by Chandran et al. (2011). We find that during
the first encounter, PSP was in close proximity to the heliospheric current
sheet (HCS) and in the slow wind. PSP crossed the HCS two times, namely at
2018/11/03 UT 01:02 and 2018/11/08 UT 19:09 with perihelion occuring on the
south of side of the HCS. We predict the plasma state along the PSP trajectory,
which shows a dominant proton parallel temperature causing the plasma to be
firehose unstable.Comment: 16 pages, 5 figures; accepted for publication in the Astrophysical
Journal Letter
Transitioning Crew Resource Management into Healthcare
Crew Resource Management (CRM) originated in the field of aviation in the early 1980s after a large proportion of transport category airplane crashes were found to have been caused by preventable nontechnical skills, i.e., crew communication and coordination. Today, CRM is applied in training by exemplifying how to effectively work with coworkers while trying to accomplish a centralized goal. CRM transitioned from aviation to healthcare through the subfield of anesthesia in the early 1990s. It then began spreading to other areas of healthcare, such as operating rooms and obstetrics departments, after the release of a report from the Institute of Medicine (2000) which reported that, the estimated national cost of preventable medical errors was $17 billion and the average number of deaths per year was 98,000.
There are many ways in which CRM training is deployed in healthcare, and thus standardization of aspects of CRM training such as length of the session, people involved, topics discussed, and assessment measures are lacking. For example, healthcare CRM training programs may last as little as an hour to as long as a few days. This is an issue because, without standardization, it is extremely difficult and unlikely to implement a consistent skill set for the medical community or accurately understand if CRM training is transferring into the healthcare setting as well as fitting into the unique scheduling that is present in healthcare. To address this concern, the current proposed paper describes the results of a literature review and analysis of how CRM is applied in healthcare.
For example, Clay‐Williams, Greenfield, Stone, and Braithwaite (2014) found that full-day training sessions for CRM did not work well with the typical 12-hour rotating shift schedule in healthcare settings. To work around this, the researchers developed a modular training, based on two sets of two-hour workshops, in which participants could self-schedule and complete the modules they felt were relevant to their personal work environment on their own time. The modules included in this study focused on communication and situational awareness. The participants found the modules to be helpful and educational. This type of modular training seems as though it could potentially benefit the healthcare field. However, more research needs to be done to determine the actual real-world impact as well as if the modular training truly aids in error prevention when skills are transferred to real-world environments.
In summary, healthcare is still in the process of implementing CRM into the different subfields of healthcare (e.g. cardiology, pediatrics, radiology, etc.) and molding the training to be more standardized and validated, however training transfer has not been properly assessed. Future research should focus on creating a more consistent training that can be soundly measured and evaluated. The longitudinal carryover effect of skill persistence involved with modular trainings versus standard 8 hour trainings has yet to be fully researched and could shed light on the most efficient and most effective version of CRM training for the medical community
Substance-specific detection of catalytically active nanoparticles in the presence of a background aerosol
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