Many older American cities lost population during the last three decades of the twentieth century, but while cities such as Boston or New York saw numbers of dwelling units remain stable or even increase, others such as Buffalo, St. Louis, Cleveland, Detroit, and Pittsburgh lost large fractions of their dwelling units. This study decomposes decadal population changes from 1970 through 2000 for ...

Is there an ideal city form? As cities proliferate worldwide this has become a central question underpinning sustainable development and economic opportunity for billions of people. We provide extensive empirical evidence, mathematical analysis and a set of theorems to show that the answer to this question is topological, not geometric. We show that cities can be decomposed into two types of ne...

and time. However, it’s not all about machines taking over from field workers. Technology can also help to get more people involved with field work in ecology and conservation. The Earthwatch Institute (www.earthwatch.org), for instance, supports a project called My Tree Tracker, based on a smartphone app encouraging volunteers to keep an eye on the growth and health of the trees in their citie...

For the past decades humans have been placed at centre of designing information and communication technologies (ICT), leading to rise in prominence human-centred design. The field smart cities has equally adopted notions citizen participation as a way ensure that technological solutions improve people’s livelihoods. However, these kinds processes treat urban environment separate from nature, pr...

the space structure that governs cities has depended on several corresponding relations and various factors which consist of: population, job and activities, transportation patterns, urban sub-structures, various services and etc that always were connected to each other and have formed its space structure. but since these relations are more complicated in big cities, the importance of paying at...

In the frame of a European research project on air quality in urban agglomerations, data on ozone concentrations from 23 automated urban and suburban monitoring stations in 11 cities from seven countries were analysed and evaluated. Daily and summer mean and maximum concentrations were computed based on hourly mean values, and cumulative ozone exposure indices (Accumulated exposure Over a Thres...

Population decentralization has been a salient feature of the landscape of most U.S. urban areas since 1950. Nathaniel Baum-Snow (2007) documents that the aggregate population of central cities of the 139 largest metropolitan areas (henceforth, MSAs) declined by 17 percent between 1950 and 1990 while aggregate MSA population growth was 72 percent during this period. Expansion of the highway net...