Fault reactivation by fluid injection: Controls from stress state and injection rate

We studied the influence of stress state and fluid injection rate on the reactivation of faults. We conducted experiments on a saw-cut Westerly granite sample under triaxial stress conditions. Fault reactivation was triggered by injecting fluids through a borehole directly connected to the fault. Our results show that the peak fluid pressure at the borehole leading to reactivation depends on injection rate. The higher the injection rate, the higher the peak fluid pressure allowing fault reactivation. Elastic wave velocity measurements along fault strike highlight that high injection rates induce significant fluid pressure heterogeneities, which explains that the onset of fault reactivation is not determined by a conventional Coulomb law and effective stress principle, but rather by a nonlocal rupture initiation criterion. Our results demonstrate that increasing the injection rate enhances the transition from drained to undrained conditions, where local but intense fluid pressures perturbations can reactivate large faults

District-Level Supervisors: Leaders and Advocates for School Counseling

All school counselors are expected to serve as leaders and advocates in their school communities. However, many are underprepared for the work after they complete graduate-level training. The present study explored the experiences of district- level school counseling supervisors in facilitating leadership development with professional school counselors. District-level supervisors are ideally placed to support school counselors in their leadership development and advocacy work. Through a semi- structured interview process, eight district-level school counseling supervisors provided information about their leadership development experiences. Data analysis yielded four themes in this descriptive phenomenological study involving social justice, role advocacy, barriers to effective leadership, and leadership perspective. The themes are described in detail along with identity descriptors that emerged during the data collection process. Discussion of these themes contextualizes the findings within the scholarship of school counselor leadership. Implications for graduate training and post- graduate leadership development suggest opportunities to improve alignment with best practice expectations of the profession. The discussion of findings also includes recommendations for future research about district-level school counseling supervisors engaged in leadership development work with professional school counselors

Post-Newtonian gravitational radiation and equations of motion via direct integration of the relaxed Einstein equations. V. Evidence for the strong equivalence principle to second post-Newtonian order

Using post-Newtonian equations of motion for fluid bodies valid to the second post-Newtonian order, we derive the equations of motion for binary systems with finite-sized, non-spinning but arbitrarily shaped bodies. In particular we study the contributions of the internal structure of the bodies (such as self-gravity) that would diverge if the size of the bodies were to shrink to zero. Using a set of virial relations accurate to the first post-Newtonian order that reflect the stationarity of each body, and redefining the masses to include 1PN and 2PN self-gravity terms, we demonstrate the complete cancellation of a class of potentially divergent, structure-dependent terms that scale as s^{-1} and s^{-5/2}, where s is the characteristic size of the bodies. This is further evidence of the Strong Equivalence Principle, and supports the use of post-Newtonian approximations to derive equations of motion for strong-field bodies such as neutron stars and black holes. This extends earlier work done by Kopeikin.Comment: 14 pages, submitted to Phys. Rev. D; small changes to coincide with published versio

An examination of the influence of Powerpoint lectures in higher education upon student assigned reading completion

Title from PDF of title page (University of Missouri--Columbia, viewed on October 19, 2012).The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file.Dissertation advisor: Dr. Sandy HutchinsonVita.Ed. D. University of Missouri--Columbia 2011."May 2011"This mixed methods research examined the influence of PowerPoint presentation as a means of delivering content in higher education courses and the influence of this instructional mode on assigned student reading completion. Participants included faculty members and students enrolled in one program discipline area using separate student and faculty member online surveys, two student focus group sessions, a faculty focus group session, and separate student and faculty interview sessions and document analysis to collect data. The study findings revealed several emerging themes: (a) an informational sifting generation, (b) differing faculty philosophies of teaching/learning theory, and (c) co-dependence of student motivation and teacher reflective instruction. Overall the research discovered that reflective use of PowerPoint and other student centered learning perspectives could positively impact assigned reading and other characteristics of active learning in the classroom.Includes bibliographical reference

Analyzing Farmer Participation Intentions and Enrollment Rates for the Average Crop Revenue Election (ACRE) Program

The 2008 Farm Bill created the Average Crop Revenue Election (ACRE) program as a new commodity support program. Using a multinomial logit model to analyze a mail survey administered before the ACRE sign-up deadline, we identify factors driving farmer intentions regarding ACRE participation. Using a two-limit Tobit model to analyze actual county-level ACRE enrollment rates, we assess the effect of similar factors on actual farmer decisions. Results suggest that primary crops, risk perceptions, risk aversion, and program complexity were important factors. Farmer beliefs and attitudes also played key roles and were evolving during the months before the ACRE deadline.

Threshold Analysis of Non-Binary Spatially-Coupled LDPC Codes with Windowed Decoding

In this paper we study the iterative decoding threshold performance of non-binary spatially-coupled low-density parity-check (NB-SC-LDPC) code ensembles for both the binary erasure channel (BEC) and the binary-input additive white Gaussian noise channel (BIAWGNC), with particular emphasis on windowed decoding (WD). We consider both (2,4)-regular and (3,6)-regular NB-SC-LDPC code ensembles constructed using protographs and compute their thresholds using protograph versions of NB density evolution and NB extrinsic information transfer analysis. For these code ensembles, we show that WD of NB-SC-LDPC codes, which provides a significant decrease in latency and complexity compared to decoding across the entire parity-check matrix, results in a negligible decrease in the near-capacity performance for a sufficiently large window size W on both the BEC and the BIAWGNC. Also, we show that NB-SC-LDPC code ensembles exhibit gains in the WD threshold compared to the corresponding block code ensembles decoded across the entire parity-check matrix, and that the gains increase as the finite field size q increases. Moreover, from the viewpoint of decoding complexity, we see that (3,6)-regular NB-SC-LDPC codes are particularly attractive due to the fact that they achieve near-capacity thresholds even for small q and W.Comment: 6 pages, 8 figures; submitted to 2014 IEEE International Symposium on Information Theor

The Impact of Satellite Trails on H.E.S.S. Astronomical Observations

The number of satellites launched into Earth orbit has almost tripled in the last three years (to over 4000) due to the increasing commercialisation of space. Multiple satellite constellations, consisting of over 400,000 individual satellites, have either been partially launched or are proposed for launch in the near future. Many of these satellites are highly reflective, resulting in a high optical brightness that affects ground-based astronomical observations. Despite this, the potential effect of these satellites on gamma-ray-observing Imaging Atmospheric Cherenkov Telescopes (IACTs) has largely been assumed to be negligible due to their nanosecond-scale integration times. This has, however, never been verified. As IACTs are sensitive to optical wavelength light, we aim to identify satellite trails in data taken by the High Energy Stereoscopic System (H.E.S.S.) IACT array. This is to quantify the potential effects on data quality and extensive air shower event classification and reconstruction. Using night sky background measurements from H.E.S.S., we determine which observation times and pointing directions are affected most by these satellite trails, and evaluate the impact on the standard Hillas parameter variables used for event analysis. Due to the brightest trails, false trigger events can occur, however for most modern analyses the effect on astronomical results will be minimal. We observe a mild increase in the rate of trail detections over time (approximately doubling in three years), which is partially correlated with the number of satellite launches. But the fraction of H.E.S.S. data affected ($\sim0.2\%$ of dark time observations) is currently small. Nevertheless, these trails could have a non-negligible effect on future Cherenkov Telescope Array observations if advanced analysis techniques designed to lower the energy threshold of the instrument are used.Comment: 11 pages, 14 figures, 5 tables. Accepted in A&A. Reproduced with permission from Astronomy & Astrophysics, $\copyright$ ES