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This paper examines the implementation of an alternate block (A/B) schedule in three high schools in Irving, Texas. The purpose is to review how time was used in 48 randomly selected high school Algebra 1, Biology 1, English 2, and U.S. History classes. Of the 48 classes, 12 observations were conducted for each course. The findings revealed a predominance of teacher-centered instruction across all courses. Teachers spent the majority of time presenting content and monitoring student seatwork, while students primarily listened to the teacher, responded to teacher questions, and completed seatwork. The most used teacher and student materials (overhead, chalkboard, textbooks, worksheets, notebook paper) further pointed to a teacher-centered environment. Results of checklists revealed a moderately high level of student engagement, little or no individualization of instruction, and a mixed use of thinking indicators. When teacher and student time allocations were compared to expert estimates, large discrepancies were found which further accentuated the lack of student-centered instruction included in the lessons. After 4 years, most teachers had not adapted instruction to take advantage of the longer blocks of time. Implications indicate that teachers needed clear, measurable goals related to instructional strategies and the best use of 90-minute blocks of time. (Author)

AbstractOur understanding of the climatic teleconnections that drove ice-age cycles has been limited by a paucity of well-dated tropical records of glaciation that span several glacial–interglacial intervals. Glacial deposits offer discrete snapshots of glacier extent but cannot provide the continuous records required for detailed interhemispheric comparisons. By contrast, lakes located within glaciated catchments can provide continuous archives of upstream glacial activity, but few such records extend beyond the last glacial cycle. Here a piston core from Lake Junín in the uppermost Amazon basin provides the first, to our knowledge, continuous, independently dated archive of tropical glaciation spanning 700,000 years. We find that tropical glaciers tracked changes in global ice volume and followed a clear approximately 100,000-year periodicity. An enhancement in the extent of tropical Andean glaciers relative to global ice volume occurred between 200,000 and 400,000 years ago, during sustained intervals of regionally elevated hydrologic balance that modified the regular approximately 23,000-year pacing of monsoon-driven precipitation. Millennial-scale variations in the extent of tropical Andean glaciers during the last glacial cycle were driven by variations in regional monsoon strength that were linked to temperature perturbations in Greenland ice cores1; these interhemispheric connections may have existed during previous glacial cycles.

Journal peer review regulates the flow of ideas through an academic discipline and thus has the power to shape what a research community knows, actively investigates, and recommends to policymakers and the wider public. We might assume that editors can identify the 'best' experts and rely on them for peer review. But decades of research on both expert decision-making and peer review suggests they cannot. In the absence of a clear criterion for demarcating reliable, insightful, and accurate expert assessors of research quality, the best safeguard against unwanted biases and uneven power distributions is to introduce greater transparency and structure into the process. This paper argues that peer review would therefore benefit from applying a series of evidence-based recommendations from the empirical literature on structured expert elicitation. We highlight individual and group characteristics that contribute to higher quality judgements, and elements of elicitation protocols that reduce bias, promote constructive discussion, and enable opinions to be objectively and transparently aggregated.

Between 1912 and 1914, the Anglo-American popularizer of astronomy, Mary Proctor, undertook a tour of Australia and New Zealand in order to promote a solar observatory project that would ultimately be realized as the Mount Stromlo Observatory in Australia. Proctor came at the request of Walter Geoffrey Duffield, who would go on to be the first Director of the Mt Stromlo Observatory and who saw the need to raise funds and public support for the project. Proctor’s tour was high-profile and nearly saw the realization of a solar observatory as part of the Cawthron Institute at Nelson, New Zealand. Despite this, Proctor’s tour is absent from histories of Mount Stromlo and, until recently, had also been overlooked in New Zealand. I argue that this historical lacuna speaks to a number of historiographical biases: for success over failure; against the role of public activities in scientific work; and downplaying the contribution of women. Mary Proctor was a significant transitional figure in the history of early twentieth-century science-communication who should be more widely recognised.

Our understanding of the climatic teleconnections that drove ice-age cycles has been limited by a paucity of well-dated tropical records of glaciation that span several glacial–interglacial intervals. Glacial deposits offer discrete snapshots of glacier extent but cannot provide the continuous records required for detailed interhemispheric comparisons. By contrast, lakes located within glaciated catchments can provide continuous archives of upstream glacial activity, but few such records extend beyond the last glacial cycle. Here a piston core from Lake Junín in the uppermost Amazon basin provides the first, to our knowledge, continuous, independently dated archive of tropical glaciation spanning 700,000 years. We find that tropical glaciers tracked changes in global ice volume and followed a clear approximately 100,000-year periodicity. An enhancement in the extent of tropical Andean glaciers relative to global ice volume occurred between 200,000 and 400,000 years ago, during sustained intervals of regionally elevated hydrologic balance that modified the regular approximately 23,000-year pacing of monsoon-driven precipitation. Millennial-scale variations in the extent of tropical Andean glaciers during the last glacial cycle were driven by variations in regional monsoon strength that were linked to temperature perturbations in Greenland ice cores1; these interhemispheric connections may have existed during previous glacial cycles.