A Study of Mentor Principal Training in Pennsylvania

Abstract The purpose of this qualitative case study was to identify, investigate, and describe the espoused Pennsylvania Principal Mentoring Network (PPMN) training program and protocols for the principals who served as mentors for newly hired principals in Pennsylvania. This study posed three research questions: (1) what was the espoused training provided to mentor principals in Pennsylvania both prior to and during their mentoring experiences that prepared them to mentor newly hired principals?; (2) what were the program coordinators’ perspectives on the espoused training delivered by the PPMN for the respective mentors and to what degree was the training program the same or different through the term of each coordinator?; and (3) how does this espoused training compare and subsequently align to the competencies required of mentor principals highlighted in the research literature? Through reviewing documents and conducting interviews, the author found that each principal mentor had participated in some form of mentor training. Each mentor principal had the opportunity to experience and access standard mentor training orientations, published newsletters and regional meetings, and the National Institute for School Leadership (NISL) five-day Instructional Leadership Institute’s condensed professional development series. The PPMN State Coordinators indicated that the PPMN attracted qualified mentor principals who modeled a results driven, research-based mentor training program. Throughout the existence of the PPMN, subtle changes to the mentor training program were identified but the focus, goals, and outcomes of the training remained intact. The PPMN mentor training process had aligned fairly consistently to the research literature base and framework for this research study. Although minimal references to adult learning theory were found in this study, it is recommended that future mentor training programs strongly consider the efficacy of including this area within the scope and sequence of the training program. In addition, due to the unavailability of certain documents and no central repository for information, future research inquiries should be geared toward existing programs that are strongly organized and currently functioning

The Local Group: The Ultimate Deep Field

Near-field cosmology -- using detailed observations of the Local Group and its environs to study wide-ranging questions in galaxy formation and dark matter physics -- has become a mature and rich field over the past decade. There are lingering concerns, however, that the relatively small size of the present-day Local Group ($\sim 2$ Mpc diameter) imposes insurmountable sample-variance uncertainties, limiting its broader utility. We consider the region spanned by the Local Group's progenitors at earlier times and show that it reaches $3' \approx 7$ co-moving Mpc in linear size (a volume of $\approx 350\,{\rm Mpc}^3$) at $z=7$. This size at early cosmic epochs is large enough to be representative in terms of the matter density and counts of dark matter halos with $M_{\rm vir}(z=7) \lesssim 2\times 10^{9}\,M_{\odot}$. The Local Group's stellar fossil record traces the cosmic evolution of galaxies with $10^{3} \lesssim M_{\star}(z=0) / M_{\odot} \lesssim 10^{9}$ (reaching $M_{1500} > -9$ at $z\sim7$) over a region that is comparable to or larger than the Hubble Ultra-Deep Field (HUDF) for the entire history of the Universe. It is highly complementary to the HUDF, as it probes much fainter galaxies but does not contain the intrinsically rarer, brighter sources that are detectable in the HUDF. Archaeological studies in the Local Group also provide the ability to trace the evolution of individual galaxies across time as opposed to evaluating statistical connections between temporally distinct populations. In the JWST era, resolved stellar populations will probe regions larger than the HUDF and any deep JWST fields, further enhancing the value of near-field cosmology.Comment: 6 pages, 5 figures; MNRAS Letters, in pres

A new paradigm in teaching large engineering mechanics courses

This study investigated the role of a new paradigm in teaching large introductory fundamental engineering mechanics courses that combines student-centered learning and supplemental student resources. The sample consisted of close to 5000 engineering students from Iowa State University. Demographic characteristics in the study included students\u27 major, gender, performance in high school, and achievement and aptitude tests scores. Results of the study overwhelmingly showed that not only is there a difference between a class taught passively using the teacher-centered pedagogy and a class taught actively using the student-centered pedagogy, but also that the usage of the variety of student-centered pedagogies in statics of engineering is a significant predictor in student performance in mechanics of materials. The principal focus of this work was to determine if the new paradigm was successful in improving student understanding of course concepts in statics of engineering. After evaluating the effects of several variables on students\u27 academic success, the results may provide important information for both faculty and researchers and present a convincing argument to those faculty interested in a reform but hesitant to abandon conventional teaching practices. By promoting a new paradigm, the potential for improving understanding of engineering fundamentals on a larger scale may be realized

The Mass Dependance of Satellite Quenching in Milky Way-like Halos

Using the Sloan Digital Sky Survey, we examine the quenching of satellite galaxies around isolated Milky Way-like hosts in the local Universe. We find that the efficiency of satellite quenching around isolated galaxies is low and roughly constant over two orders of magnitude in satellite stellar mass ($M_{*}$ = $10^{8.5}-10^{10.5} \, M_{\odot}$), with only $\sim~20\%$ of systems quenched as a result of environmental processes. While largely independent of satellite stellar mass, satellite quenching does exhibit clear dependence on the properties of the host. We show that satellites of passive hosts are substantially more likely to be quenched than those of star-forming hosts, and we present evidence that more massive halos quench their satellites more efficiently. These results extend trends seen previously in more massive host halos and for higher satellite masses. Taken together, it appears that galaxies with stellar masses larger than about $10^{8}~M_{\odot}$ are uniformly resistant to environmental quenching, with the relative harshness of the host environment likely serving as the primary driver of satellite quenching. At lower stellar masses ($< 10^{8}~M_{\odot}$), however, observations of the Local Group suggest that the vast majority of satellite galaxies are quenched, potentially pointing towards a characteristic satellite mass scale below which quenching efficiency increases dramatically.Comment: 14 pages, 8 figure

A Dichotomy in Satellite Quenching Around L* Galaxies

We examine the star formation properties of bright (~0.1 L*) satellites around isolated ~L* hosts in the local Universe using spectroscopically confirmed systems in the Sloan Digital Sky Survey DR7. Our selection method is carefully designed with the aid of N-body simulations to avoid groups and clusters. We find that satellites are significantly more likely to be quenched than a stellar mass-matched sample of isolated galaxies. Remarkably, this quenching occurs only for satellites of hosts that are themselves quenched: while star formation is unaffected in the satellites of star-forming hosts, satellites around quiescent hosts are more than twice as likely to be quenched than stellar-mass matched field samples. One implication of this is that whatever shuts down star formation in isolated, passive L* galaxies also plays at least an indirect role in quenching star formation in their bright satellites. The previously-reported tendency for "galactic conformity" in color/morphology may be a by-product of this host-specific quenching dichotomy. The S\'ersic indices of quenched satellites are statistically identical to those of field galaxies with the same specific star formation rates, suggesting that environmental and secular quenching give rise to the same morphological structure. By studying the distribution of pairwise velocities between the hosts and satellites, we find dynamical evidence that passive host galaxies reside in dark matter halos that are ~45% more massive than those of star-forming host galaxies of the same stellar mass. We emphasize that even around passive hosts, the mere fact that galaxies become satellites does not typically result in star formation quenching: we find that only ~30% of ~0.1 L* galaxies that fall in from the field are quenched around passive hosts, compared with ~0% around star forming hosts.Comment: 14 pages, 9 figure

Environmental Quenching of Low-Mass Field Galaxies

In the local Universe, there is a strong division in the star-forming properties of low-mass galaxies, with star formation largely ubiquitous amongst the field population while satellite systems are predominantly quenched. This dichotomy implies that environmental processes play the dominant role in suppressing star formation within this low-mass regime (${M}_{\star} \sim 10^{5.5-8}~{\rm M}_{\odot}$). As shown by observations of the Local Volume, however, there is a non-negligible population of passive systems in the field, which challenges our understanding of quenching at low masses. By applying the satellite quenching models of Fillingham et al. (2015) to subhalo populations in the Exploring the Local Volume In Simulations (ELVIS) suite, we investigate the role of environmental processes in quenching star formation within the nearby field. Using model parameters that reproduce the satellite quenched fraction in the Local Group, we predict a quenched fraction -- due solely to environmental effects -- of $\sim 0.52 \pm 0.26$ within $1< R/R_{\rm vir} < 2$ of the Milky Way and M31. This is in good agreement with current observations of the Local Volume and suggests that the majority of the passive field systems observed at these distances are quenched via environmental mechanisms. Beyond $2~R_{\rm vir}$, however, dwarf galaxy quenching becomes difficult to explain through an interaction with either the Milky Way or M31, such that more isolated, field dwarfs may be self-quenched as a result of star-formation feedback.Comment: 9 pages, 4 figures, MNRAS accepted version, comments welcome - RIP Ducky...gone but never forgotte

Optimal partial-arcs in VMAT treatment planning

Purpose: To improve the delivery efficiency of VMAT by extending the recently published VMAT treatment planning algorithm vmerge to automatically generate optimal partial-arc plans. Methods and materials: A high-quality initial plan is created by solving a convex multicriteria optimization problem using 180 equi-spaced beams. This initial plan is used to form a set of dose constraints, and a set of partial-arc plans is created by searching the space of all possible partial-arc plans that satisfy these constraints. For each partial-arc, an iterative fluence map merging and sequencing algorithm (vmerge) is used to improve the delivery efficiency. Merging continues as long as the dose quality is maintained above a user-defined threshold. The final plan is selected as the partial arc with the lowest treatment time. The complete algorithm is called pmerge. Results: Partial-arc plans are created using pmerge for a lung, liver and prostate case, with final treatment times of 127, 245 and 147 seconds. Treatment times using full arcs with vmerge are 211, 357 and 178 seconds. Dose quality is maintained across the initial, vmerge, and pmerge plans to within 5% of the mean doses to the critical organs-at-risk and with target coverage above 98%. Additionally, we find that the angular distribution of fluence in the initial plans is predictive of the start and end angles of the optimal partial-arc. Conclusions: The pmerge algorithm is an extension to vmerge that automatically finds the partial-arc plan that minimizes the treatment time. VMAT delivery efficiency can be improved by employing partial-arcs without compromising dose quality. Partial arcs are most applicable to cases with non-centralized targets, where the time savings is greatest