Passing Muster: Evaluating Teacher Evaluation Systems

Describes how state or federal governments could reward exceptional teachers based on a uniform standard across various district-level teacher evaluation systems by determining the systems' reliability in predicting future performance. Includes Q & A

Evaluating Teachers: The Important Role of Value-Added

Outlines issues for evaluating teachers based on value added -- their contribution to student learning -- and the use of value added information, implications of classifying teachers, and reliability compared with other fields and evaluations

Searching for giga-Jansky fast radio bursts from the Milky Way with a global array of low-cost radio receivers

If fast radio bursts (FRBs) originate from galaxies at cosmological distances, then their all-sky rate implies that the Milky Way may host an FRB on average once every 30-1500 years. If FRBs repeat for decades or centuies, a local FRB could be active now. A typical Galactic FRB would produce a millisecond radio pulse with ~1 GHz flux density of ~3E10 Jy, comparable to the radio flux levels and frequencies of cellular communication devices (cell phones, Wi-Fi, GPS). We propose to search for Galactic FRBs using a global array of low-cost radio receivers. One possibility is to use the ~1GHz communication channel in cellular phones through a Citizens-Science downloadable application. Participating phones would continuously listen for and record candidate FRBs and would periodically upload information to a central data processing website, which correlates the incoming data from all participants, to identify the signature of a real, globe-encompassing, FRB from an astronomical distance. Triangulation of the GPS-based pulse arrival times reported from different locations will provide the FRB sky position, potentially to arc-second accuracy. Pulse arrival times from phones operating at diverse frequencies, or from an on-device de-dispersion search, will yield the dispersion measure (DM) which will indicate the FRB source distance within the Galaxy. A variant of this approach would be to use the built-in ~100 MHz FM-radio receivers present in cell phones for an FRB search at lower frequencies. Alternatively, numerous "software-defined radio" (SDR) devices, costing ~$10 US each, could be plugged into USB ports of personal computers around the world (particularly in radio quiet regions) to establish the global network of receivers.Astronom

Periodic optical variability and debris accretion in white dwarfs: a test for a causal connection

Recent Kepler photometry has revealed that about half of white dwarfs (WDs) have periodic, low-level (~ 1e-4 - 1e-3), optical variations. Hubble Space Telescope (HST) ultraviolet spectroscopy has shown that up to about one half of WDs are actively accreting rocky planetary debris, as evidenced by the presence of photospheric metal absorption lines. We have obtained HST ultraviolet spectra of seven WDs that have been monitored for periodic variations, to test the hypothesis that these two phenomena are causally connected, i.e. that the optical periodic modulation is caused by WD rotation coupled with an inhomogeneous surface distribution of accreted metals. We detect photospheric metals in four out of the seven WDs. However, we find no significant correspondence between the existence of optical periodic variability and the detection of photospheric ultraviolet absorption lines. Thus the null hypothesis stands, that the two phenomena are not directly related. Some other source of WD surface inhomogeneity, perhaps related to magnetic field strength, combined with the WD rotation, or alternatively effects due to close binary companions, may be behind the observed optical modulation. We report the marginal detection of molecular hydrogen in WD J1949+4734, only the fourth known WD with detected H_2 lines. We also re-classify J1926+4219 as a carbon-rich He-sdO subdwarf.Comment: MNRAS, in pres

Top 100 Urology Influences on Twitter: Is Social Media Influence Associated with Academic Impact?

Introduction: The purpose of this cross-sectional study is to identify and describe the top 100 urology influencers on the social media platform Twitter. Furthermore, we aim to correlate each individual\u27s Twitter influence with academic impact in urology. Materials and Methods: Twitter influence scores for the topic search “urology” were collected in April 2022 using the Right Relevance software, which accounts for the individual\u27s connections (followers/following) to other influencers in urology as well as engagement (likes, retweets, and views) on the platform. The top 100 personal accounts with the highest computed scores were linked to individuals’ names, all-time h-index, geographic location, specialty, sex, and board certification. We examined the Pearson correlation coefficient between influence rank and h-index. Results: We identified the top 100 Twitter influencers on the topic of “urology.” The majority are from the United States (63%), male (85%), and are practicing urologists (93%). Ninety-three percent (93%) of U.S. urology influencers are board certified. Only 22 out of the 50 states are represented. The second most common country is the United Kingdom with 11 urology influencers. The median all-time h-index is 41.5 (IQR: 27 – 55.5). There is a weak positive coefficient (r=0.26) between the influence rank and h-index (p=0.021). Conclusions: The top Twitter influencers in urology are mostly Board-certified U.S. urologists. Collectively, influencers have a relatively greater academic impact compared to the average urologist, although there is a weak positive correlation between Twitter influence and h-index among top Twitter influencers