Archive for October, 2007
A fluvial record of active fault-propagation folding, Salsomaggiore anticline, northern Apennines, Italy
The Salsomaggiore anticline in the northern Apennines is an actively growing fault-propagation fold that is flanked by a suite of early Middle Pleistocene (~0.8 Ma) to Recent fluvial terraces, which reveal a foreland-migrating wave of coupled incision and aggradation, interpreted to reflect the response of a fluvial system to progressive vertical and lateral fold-propagation. This ~10km-wavelength fold resides ~25 km hinterward of the modern structural front and exhibits a complex growth history extending back to at least the middle Miocene. Langhian-Messinian, marginal- to deep-marine clastics are folded about a NW-SE trending axis, record the majority of fold growth, and are superimposed by the Ligurian nappe and Pliocene-Recent deep-marine, marginal-marine, and fluvial strata with shallowing upward dips. Active growth is documented by fluvial terraces, recent seismicity, deflected stream channels, first-order stream gradients, and long-profile modeling. › Continue reading
Position of Watershed Divides from Filtered Topography as an Indicator of Geodynamic Process: Using the Snake River and Greater Yellowstone Area as a Case Study
The spatial position of present-day and synthesized regional-scale drainage basin divides is an underutilized geomorphic metric that can be used to identify various overlapping geodynamic processes responsible for landscape evolution. In considering the stability or mobility of regional-scale drainage basin divides, two end-member scenarios may be envisioned. The first is where the divide remains spatially fixed over long periods of time during which an overthickened orogenic crustal root is passively consumed via erosional unloading and its isostatic response. The second is where divides actively migrate in response to dynamic mantle support of topography. Knowing that active drainage divide migration can be a key feature in distinguishing between passive and active geodynamic settings, we investigate drainage divide migration potential in the greater Yellowstone region (GYR), a geodynamically active area where the processes influencing the present-day topography are fairly well defined. The GYR is an opportune location for this investigation because contrasting models have been proposed to explain the parabolic shape of elevated topography and active seismicity that outline the imprint of hypothesized hotspot activity. Drainage divides synthesized from topography filtered at 50, 100, and 150 km wavelengths within the GYR show that the locations of the actual and synthetic Snake River drainage divides are controlled by both dynamic and flexural mechanisms in the eastern GYR, but by flexural mechanisms only in the western GYR. The location of the actual divide deviates from its predicted position in the filtered topography where tectonic controls, such as active faults (e.g., Centennial and Teton faults), have uplifted large footwall blocks. Our results are consistent with the notion of a northeastward-propagating GYR topographic and seismic parabola, and suggest that adjacent Basin and Range extension follows from, rather than precedes, GYR dynamic topography. Furthermore, our analysis suggests that eastward migration of the Snake River drainage divide lags behind the continued northeastward propagation of high-standing topography associated with the Yellowstone geophysical anomaly by 12 m.y.
Nursery Rhymes and Children’s Games in the Plays of Tina Howe
Tina Howe uses nursery rhymes and childrens games much as parents use them: to amuse and distract, while attending to and instructing in the nuance and cadence of language. When separated from the rhythm and rhyme, the words of the nursery rhymes in One Shoe Off (the title itself being from a nursery rhyme) and Prides Crossing depict fanciful and unnerving themes. Behind the rhythm and rhyme lie lifes oddities. By attending to Howes use of nursery rhymes and games in One Shoe Off and Prides Crossing, her audience must return to their earliest language acquisition to contemplate what they have taken for granted, while being jolted into realizing they had accepted the surreal early in their lives, and examine how Howes absurdist themes use those nursery rhymes as resonance for the study of language, its use in her plays, and in their own lives.
Howes use of childrens games in Birth and After Birth (musical chairs), Approaching Zanzibar (geography game), One Shoe Off (dress up and Concentration), Coastal Disturbances (shell game), Prides Crossing (dress up and croquet) serves a similar purpose. These games instruct children in how to play by prescribed rules. Ironically, even with rules someone must win and someone must lose. Howe, as with the nursery rhymes, uses her absurdist skills to demonstrate how these childhood games contribute to the delusion that there are prescribed rules for life.
Design Strategies for Enhancing Social Connectedness in Online Learning: An Instructor’s Guide to “E-mmediacy”
Despite the unprecedented growth and availability of Web-based instruction and the great promise of any time/any place learning, it appears that higher than average attrition rates remain an issue for online learning (King, 2002). Students in online courses report missing the interpersonal interactions they more typically have with each other and with their instructors in face-to-face courses (Reisetter & Boris, 2004). Similarly, instructors report feeling out of touch with their students (Willis & Dickinson, 1997). Zielinski (2000) contended that this disconnectedness is directly related to the lack of immediate feedback and social cues that are so prevalent among classroom-group members in traditional courses. › Continue reading
Do Wireless Laptops Invite Instructional Change? A Multi-Case Study of High School Teachers One-to-One Computing Implementations
As a part of a state grant, researchers conducted this year-long evaluation case study of an urban school district’s laptop initiative during the 2006-2007 academic year. The laptops were implemented in 9th grade English Language Arts, Math, and Special Education Department classes. Comprised of three data collection points, this study triangulated observation, survey, and interview data gathered from various sources: principals, assistant principals, department chairs, teachers, and students. › Continue reading