There has been increasing recognition of the importance of informal interactions in organizations, but research examining the effects of the physical environment on informal interaction has produced contradictory results and practical attempts to control the level of informal interaction by design have been marked by unintended consequences. Drawing on a qualitative study of informal interactions observed in photocopier rooms in three organizations, this paper builds on the work of ecological psychologist James Gibson to develop a theory of the affordances of informal interaction. The affordances of an environment are the possibilities for action called forth by it to a perceiving subject. Research on affordances has typically focused on the affordances of individual behavior. We introduce the notion of social affordances and identify the social and physical characteristics that produce the propinquity, privacy, and social designation necessary for an environment to afford informal interactions. The theory of social affordances provides a lens through which to reinterpret the conflicting results of previous studies and to reexamine the seemingly simple water-cooler around which the organization gathers.

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Nightsat is a concept for a satellite system capable of global observation of the location, extent and brightness of night-time lights at a spatial resolution suitable for the delineation of primary features within human settlements. Based on requirements from several fields of scientific inquiry, Nightsat should be capable of producing a complete cloud-free global map of lights on an annual basis. We have used a combination of high-resolution field spectra of outdoor lighting, moderate resolution colour photography of cities at night from the International Space Station, and high-resolution airborne camera imagery acquired at night to define a range of spatial, spectral, and detection limit options for a future Nightsat mission. The primary findings of our study are that Nightsat should collect data from a near-synchronous orbit in the early evening with 50 to 100 m spatial resolution and have detection limits of 2.5E 28 Watts cm 22 sr 21 mm 21 or better. Although panchromatic low-light imaging data would be useful, multispectral low-light imaging data would provide valuable information on the type or character of lighting; potentially stronger predictors of variables, such as ambient population density and economic activity; and valuable information to predict response of other species to artificial night lighting. The Nightsat mission concept is unique in its focus on observing a human activity, in contrast to traditional Earth observing systems that focus on natural systems.

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Population growth in West Africa has outpaced local efforts to expand potable water services, and private sector sale of packaged drinking water has filled an important gap in household water security. Consumption of drinking water packaged in plastic sachets has soared in West Africa over the last decade, but the long-term implications of these changing consumption patterns remain unclear and unstudied. This paper reviews recent shifts in drinking water, drawing upon data from the 2003 and 2008 Demographic and Health Surveys, and provides an overview of the history, economics, quality, and regulation of sachet water in Ghana’s Accra-Tema Metropolitan Area. Given the pros and cons of sachet water, we suggest that a more holistic understanding of the drinking water landscape is necessary for municipal planning and sustainable drinking water provision.

In this article, we propose a theory of the cultural evolution of the firm. We apply cultural and evolutionary thinking to the questions posed by theories of the firm: What are firms and why do they exist? We argue that firms are best thought of as cultures, as social distributions of modes of thought and forms of externalization. Using the term ‘meme’ to refer collectively to cultural modes of thought (ideas, beliefs, assumptions, values, interpretative schema, and know-how), we describe culture as a social phenomenon, patterns of symbolic communication and behavior that are produced as members of the group enact the memes they have acquired as part of the culture. Memes spread from mind to mind as they are enacted and the resulting cultural patterns are observed and interpreted by others. The uncertainties of interpretation and the possibilities of reinterpretation and recontextualization create variation in the memes as they spread. Over time, firms evolve as a process of the selection, variation, and retention of memes. Our claim is that understanding firms in this way provides a new perspective (what we call the ‘meme’s-eye view’) on the question of why we have the firms we have and, by allowing us to shed the functionalist assumptions shared by both economics and knowledge-based theories of the firm, makes possible a genuinely descriptive, as opposed to normative, theory of why we have the firms that we have.

Intraurban differentials in safe drinking water in developing cities have been exacerbated by rapid population growth that exceeds expansion of local water infrastructure. In Accra, Ghana, municipal water is rationed to meet demand, and the gap in water services is increasingly being filled by private water vendors selling packaged “sachet” water. Sachets extend drinking water coverage deeper into low-income areas and alleviate the need for safe water storage, potentially introducing a health benefit over stored tap water. We explore correlates of using sachets as the primary drinking water source for 2,093 women in 37 census areas classified as slums by UN-Habitat, and links between sachet water and reported diarrhea episodes in a subset of 810 children under five. We find that neighborhood rationing exerts a strong effect on a household's likelihood of buying sachet water, and that sachet customers tend to be the poorest of the poor. Sachet use is also associated with higher levels of self-reported overall health in women, and lower likelihood of diarrhea in children. We conclude with implications for sachet regulation in Accra and other sub-Saharan cities facing drinking water shortages.

Slums are home to a large fraction of urban residents in cities of developing nations, but little attempt has been made to go beyond a simple slum/non-slum dichotomy, nor to identify slums more quantitatively than through local reputation. We use census data from Accra, Ghana, to create an index that applies the UN-Habitat criteria for a place to be a slum. We use this index to identify neighborhoods on a continuum of slum characteristics and on that basis are able to locate the worst slums in Accra. These do include the areas with a local reputation for being slums, lending qualitative validation to the index. We show that slums also have footprints that can be identified from data classified from satellite imagery. However, variability among slums in Accra is also associated with some variability in the land cover characteristics of slums.