The ubiquitous use of per capita indicators for ranking and comparing cities is particularly egregious because it implicitly assumes that the baseline, or null hypothesis, for any urban characteristic is that it scales linearly with population size. In other words, it presumes that an idealized city is just the linear sum of the activities of all of its citizens, thereby ignoring its most essential feature and the very point of its existence, namely, that it is a collective emergent agglomeration resulting from nonlinear social and organizational interactions. Cities are quintessentially complex adaptive systems and, as such, are significantly more than just the simple linear sum of their individual components and constituents, whether buildings, roads, people, or money. There is an approximately 15 percent increase in all socioeconomic activity with every doubling of the population size, which happens almost independently of administrators, politicians, planners, history, geographical location, and culture.
In assessing the performance of a particular city, we therefore need to determine how well it performs relative to what it has accomplished just because of its population size. By analogy with the discussion on determining the strongest champion weight lifter by measuring how much each deviated from his expected performance relative to the idealized scaling of body strength, one can quantify an individual city’s performance by how much its various metrics deviate from their expected values relative to the idealized scaling laws. This strategy separates the truly local nature of a city’s organization and dynamics from the general dynamics and structure common to all cities. As a result, several fundamental questions about any individual city can be addressed, such as how exceptional it is relative to its peers, what timescales are relevant for local policy to take effect, what are the local relationships between economic development, crime, and innovation, to what extent is it unique, and to what extent can it be considered a member of a family of like cities.
Half a billion years ago on Earth, after the Cambrian explosion had created an astonishing array of new species, there was still no life on land. No complex life anyway. No plants, no animals, certainly nothing that even compared to the great diversity of life in the sea, which teemed with trilobites, crustaceans, bristly worms, and soft squid-like creatures. Most major animals groups that exist today originated in the sea at this time.
Fast forward to the present, and it is now the land that has a dizzying array of species. In particular: flowering plants, fungi, and insects, so many damn insects. By one estimate, there are five times as many terrestrial species as marine species today. So how did biodiversity in the ocean—despite its head start, despite its larger share of the Earth’s surface area—come to fall so far behind biodiversity on land?
A heartwarming book about Alzheimer's disease? Seriously? Rachel Khong's first novel comes adorned with rows of hot pink, orange, and yellow lemons, but a pitcher of lemonade would have been apt too, for this is a writer who clearly knows how to squeeze the sweetness out of the tart fruit life throws at you.
The whole collection is an account – in the words of the narrator of the Poe-inspired story “Imp of the Perverse” – of “so much ugly craving”. The shape and conception of the stories are often shocking enough, but Caldwell’s linguistic verve is what keeps you paying attention, fascinated and appalled.