This study analyzed quantitative and qualitative data from classroom observations combined with instructor survey results to characterize the application of reformed teaching practices in undergraduate geoscience classes in the United States. Trained observers used the Reformed Teaching Observation Protocol (RTOP) to score 204 geoscience classes. Observed faculty represent a diversity of institutions, teaching rank, and years of experience. Classrooms observed included introductory and upper-level undergraduate courses that ranged in size from 6 to 275 students. Total RTOP scores do not correlate with class size, class level, institution type, instructor gender, instructor rank, or years of teaching experience. Classroom instruction was separated into three categories based on total RTOP scores: Teacher Centered (≤30), Transitional (31-49), or Student Centered (≥50). Statistical analyses of RTOP subscales and individual item scores are used to identify the instructional practices that are characteristic of each category. Instructor survey responses and qualitative classroom observations provide additional details about instructional practices common within each instructional category. Results of these analyses provide a coherent picture of instructional strategies used in geoscience classrooms. Instruction in the most Student Centered classrooms differs from that in Transitional and Teacher Centered classrooms in at least one of three ways. Student Centered classes are more likely to include (1) students engaged in class activities with one another; (2) activities in which instructors assess student learning and adjust lessons accordingly; and (3) opportunities for students to answer and pose questions that determine the focus of a lesson.
We compared 236 geoscience instructors' histories of professional development (PD) participation with classroom observations using the Reformed Teaching Observation Protocol (RTOP) that describe undergraduate classes as Student-Centered (score ≥ 50), Transitional (score 31-49) or Teacher-Centered (score ≤ 30). Instructors who attended PD (n = 111) have higher average RTOP scores (44.5 vs. 34.2) and are more frequently observed teaching Student-Centered classes (33% vs. 13%) than instructors with no PD (p < 0.001). Instructors who attended PD that is topically-aligned with content taught during the classroom observation are likely to have RTOP scores that are higher by 13.5 points (p < 0.0001), and are 5.6 times more likely to teach a Student-Centered class than instructors without topically-aligned PD. Comparable odds of teaching Student-Centered classes (5.8x) occur for instructors who attended two topical PD events but were observed teaching a different topic. Models suggest that instructors with at least 24 h of PD are significantly more likely to teach a Student-Centered class than instructors with fewer hours. Our results highlight the effectiveness of disciplinespecific PD in impacting teaching practices, and the importance of attending more than one such PD event to aid transfer of learning.
Abstract-Pb-isotopic ratios have been determined on massive sulphides from the Troodos ophiolite and their inferred source rocks: epidosites and greenschist altered dikes. The latter have distinctly higher Pb-isotope ratios than the sulphides. The high 207 Pb/ 204 Pb ratios for the whole rocks indicate the involvement of an old (sedimentary) Pb-component. Extensive leaching of three epidosite samples shows that the radiogenic Pb can be removed and the resulting trend for the leached samples is consistent with a Pb-Pb age of ϳ95 Ma for these rocks. Inferred initial Pb isotope ratios are similar to those of the sulphides (this study) and fresh glasses from the Akaki Canyon in Cyprus. Therefore the Pb incorporated in the massive sulphides may originate from these greenschist facies hydrothermally altered rocks.The isotopic composition of the leachate Pb points toward a sedimentary origin. Calculation of the Pb-isotopic ratios for 90 Ma old "average" Troodos sediment shows that the "foreign" Pb in the epidosites may very well be derived from this source. This Pb probably does not reside within the mineral lattices of these metamorphic rocks, but rather is adsorbed on mineral surfaces or is present in microscopic particulate matter that may have been filtered from the circulating seawater. Unmodified seawater is considered an unlikely Pb source because of the extremely small dissolved Pb contents of seawater. Furthermore, no seawater or sedimentary signature is evident in the sulphides. Several models of Pb transport from different sources into these rocks may be envisaged, such as dissolution of Miocene evaporites and brine formation, equilibration of pore waters to the Pb isotope ratios of host sediments, and direct infiltration of deep sea particulate matter from the nepheloid layer. With the limited amount of data presently available it is impossible to critically determine the most likely processes of Pb transport.
The investigation of archaeological ceramics has a long and varied history with regard to the analytical instrumentation used (for gcneral examples, see Peacock 1970; Bishop er al. 1982; Rice 1987; Pollard er al. 2007). In recent years newer applications have been used for the analysis of ceram ic materials as wcll, including rCP-MS (Fenno et al. 2008; Man nino and Orecchio 20 1 I) and INAA (G lascock 1992; Neff 2000). In most cases the motivation to obtain chemical concentrations from archaeological ceramics has been to establish the source of the clay matrix. This has proven possible using instrumentation with low detection limits (i .c. trace element analysis techniques such as NAA, ICP, AAS, and WD-XRF). Handheld X-ray fluorescence spectrometry was developed in the carly 1960's (Piorek 1997) but did not enter the world of archaeology. outside of isolated research , until the early to mid 2000's when the instrumentation became more affordable (e.g. Uda
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