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The problem of effective learning in college classrooms, especially in a large lecture setting, has been a topic of discussion for a considerable span of time. Most efforts to improve learning incorporate various forms of student-active learning, such as in-class investigations or problems, group discussions, collaborative examinations and interactive technology such as i-clicker. Team-Based Learning (TBL) is a classroom paradigm that all but eliminates the standard lecture and shifts exams from an end-of-unit exercise to a preparatory role. Adapting TBL to an introductory oceanography course has yielded mixed results. Student satisfaction as measured by course evaluations has increased in several important indicators, but not in summative questions. Final grades have also continued at high levels, and discussions around in-class investigations have become increasingly sophisticated, but performance on certain exam components associated with higher-order learning has declined. The classroom environment may play a major role, with TBL showing greater effectiveness in a TBL-designed facility compared with a traditional auditorium.

Active learning promotes higher-level reasoning, and it can be achieved in large classes without wholesale changes in class format. Applicable methods include in-class mini-investigations, robust multiple-choice exam questions, online quizzes or review, and cooperative learning, particularly during exams. Data gleaned from observing student performance, surveys, and interviews confirm the efficacy of these techniques. (Contains 3 tables and 3 figures.)

Active learning promotes higher-level reasoning, and it can be achieved in large classes without wholesale changes in class format. Applicable methods include in-class mini-investigations, robust multiple-choice exam questions, online quizzes or review, and cooperative learning, particularly during exams. Data gleaned from observing student performance, surveys, and interviews confirm the efficacy of these techniques. [ABSTRACT FROM AUTHOR]

Tertiary sediments around Lake Rudolf (now Lake Turkana) in the East African Rift Valley have yielded abundant palaeontological and palaeoanthropological remains. The present study provides a basis for interpreting the ancient lake environment and furthering our knowledge of rift valley lacustrine deposits. Bottom sediments in Lake Rudolf are fine-grained (average 71% clay) well laminated and have montmorillonite, kaolinite and illite as the principal clay minerals. The sediments are relatively poor in silica (40-45%) but rich in Fe[SUB2]O[SUB3] (10%). Both mineral proportions and chemical composition change systematically over the area of the lake and delineate four sedimentological provinces: (1) iron-rich, silty kaolinitic muds (Omo Delta); (2) iron-rich, fine-grained montmorillonite muds (North Basin); (3) silty montmorillonite muds rich in Na[SUB2]O and K[SUB2]O (Central Delta); and (4) argillaceous calcite silts (South Basin). Omo Delta and North Basin seadiments are derived from the volcanics of the Ethiopian plateau; the source of Central Delta sediments is the Precambrian metamorphic terrain of the rift valley margin; the South Basin has a restricted detrital input. The water in the lake is alkaline (pH 9.2) and moderately saline (TDS = 2500 p.p.m.). Comparisons with influent water from the Omo River indicate a 200-fold concentration for the lake water. Models based on equilibrium between sediments and water column account for most of the non-conservative chemical components in the lake water. Sedimentation rates are high (about 1 m per 1000 years) and the dominance of detrital sediments makes Lake Rudolf unusual in comparison with other closed-basin lakes in the African Rift Valley although some similarities with ancient rift valley deposits are suggested. [ABSTRACT FROM AUTHOR]

The Fort River watershed in central Massachusetts receives precipitation with a composition similar to that in Hubbard Brook (New Hampshire), yet the average stream water chemistry is substantially different, showing higher pH and TDS. This is largely a function of bedrock and surficial geology, and chemical differences among small streams within the Fort River watershed are apparently controlled by the composition and thickness of the prevailing surficial cover. The surficial deposits determine groundwater and surface water flow paths, thereby affecting the resultant contact time with mineral matter and the chemistry of the runoff. Despite the rural setting, over 95% of the annual sodium and chloride in the streams comes from road salt; after correcting for this factor, cation denudation rates are about equal to those at Hubbard Brook. However, silica removal is occurring at a rate more than 30% greater in the Fort River. When climatic conditions in Hubbard Brook and Fort River are normalized, weathering rates appear consistently higher in the Fort River, reflecting differences in weathering processes (i.e., cation exchange and silicate breakdown) and hydrogeology. Because of uncertainties in mechanisms of cation removal from watersheds, the silica denudation rate may be a better index of weathering intensity. [ABSTRACT FROM AUTHOR]