We present the first global inventory of the spatial distribution and density of constructed impervious surface area (ISA). Examples of ISA include roads, parking lots, buildings, driveways, sidewalks and other manmade surfaces. While high spatial resolution is required to observe these features, the new product reports the estimated density of ISA on a one-km2 grid based on two coarse resolution indicators of ISA – the brightness of satellite observed nighttime lights and population count. The model was calibrated using 30-meter resolution ISA of the USA from the U.S. Geological Survey. Nominally the product is for the years 2000-01 since both the nighttime lights and reference data are from those two years. We found that 1.05% of the United States land area is impervious surface (83,337 km2) and 0.43 % of the world's land surface (579,703 km2) is constructed impervious surface. China has more ISA than any other country (87,182 km2), but has only 67 m2 of ISA per person, compared to 297 m2 per person in the USA. The distribution of ISA in the world's primary drainage basins indicates that watersheds damaged by ISA are primarily concentrated in the USA, Europe, Japan, China and India. The authors believe the next step for improving the product is to include reference ISA data from many more areas around the world.

Teaching is complex; teachers and school leaders crave more meaningful collaborative experiences to make sense of that complexity. However, the structural, cultural, and historical factors involved with schooling impede the extent to which teachers can collaborate. Teachers spend five to six periods of the day teaching classes, largely working in isolation from each other; their remaining time is spent tending to administrative tasks, answering emails, or grading. For schools to work around the persistent structural constraints to establish a sincere and thoughtful collaborative culture they must approach collaboration differently. Collaborative cultures emerge from authentic and relevant problem solving. Teachers will see collaboration as an integral feature of their work when the problems they are asked to solve are specific to their practice, are common to a majority of teachers in a particular school, and when solving the problem demands they collaborate with colleagues.

In collaborative groups, teachers negotiate the tension between working as a cohesive group and confronting differences of opinion and practice. Varied status between teachers can complicate their ability to accomplish the goals of collaboration. In this case study, we describe how a group of secondary English teachers redesigned curriculum and explain how status shaped their collaborative practice. We use positioning theory to examine how teachers managed variable status to maintain a collaborative group process. Findings suggest the high-status teacher shaped inclusive collaborative routines that afforded novice teachers the space to initiate discussions focused on problems of practice.

A comprehensive high school in Bellevue, Wash., embraces problem-based learning as its strategy for improvement. Supported by a federal i3 grant, the school spent five years preparing for a widespread launch of PBL at the school. After several years of implementation, researchers learned that students perform the same or better on standardized measures when provided with sustained, rich PBL learning experiences. Those benefits were felt by all students, regardless of socioeconomic or linguistic status, or special learning needs.

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