The Changing Distributions of New Ph.D. Economists and Their Employment: Implications for the Future

[Excerpt] Academic careers are no longer the be-all and end-all for economics Ph.D. students, and the findings and background provided by Siegfried and Stock help to explain why this is so. The median age at which individuals receive economics Ph.D.\u27s in the Siegfried and Stock sample is 32. While they are somewhat surprised at this finding, it parallels the experiences of many other fields. Increasingly, students are working before proceeding to doctoral studies. Often Ph.D. students in economics enter their programs after having spent several years working for government agencies or research consulting companies—work that has whetted their appetites for graduate study in economics that will enable them to make greater contributions in the policy arena. As these students proceed through doctoral studies, average time to degree has also increased. It is unclear whether this has occurred across institutions, or whether the phenomenon is a byproduct of Ph.D.\u27s increasingly coming from lower-ranked institutions at which financial support for graduate students is less adequate. Less adequate financial support is known to lengthen time to degree and reduce doctoral completion rates (Ehrenberg and Mavros, 1995)

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 $\epsilon_p$. Enhanced proton temperatures are observed when $\epsilon_p$ is larger than a critical value ($\sim 0.019 - 0.025$). This enhancement strongly depends on the proton plasma beta ($\beta_{||p}$); when $\beta_{||p} \ll 1$ only the perpendicular proton temperature $T_{\perp}$ increases, while for $\beta_{||p} \sim 1$ increased parallel and perpendicular proton temperatures are both observed. For $\epsilon_p$ smaller than the critical value and $\beta_{||p} \ll 1$ no enhancement of $T_p$ is observed while for $\beta_{||p} \sim 1$ minor increases in $T_{\parallel}$ 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 $\epsilon_p > \epsilon_{\rm crit}$ 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" $\lambda_D$, 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 $\rho_i$, ion inertial length $d_i$, ion sound radius $\rho_s$, proton-cyclotron resonance scale $\rho_c$ and disruption scale $\lambda_D$ as a function of $\beta_{\perp i}$. We find that the steepest spectral indices of the dissipation range occur when $\beta_e$ 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 $\lambda_D$. Our findings suggest that, at least at low $\beta_e$, 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 ($\beta_\parallel \gtrsim 1$) 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