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Biomedical subjects

M Batty

Publications and source records attributed to M Batty.

8 recordsLinked to original sources
PubMed2002

Visual categorization during childhood: an ERP study.

Categorization is a basic means of organizing the world around us and offers a simple way to process the mass of stimuli one perceives every day. The ability to categorize appears early in infancy, and has important ramifications for the acquisition of other cognitive capacities, but little is known of its development during childhood. We studied 48 children (7-15 years of age) and 14 adults using an animal/nonanimal visual categorization task while event-related potentials (ERPs) were recorded. Three components were measured: P1, N2, and P3. Behaviorally, the children performed the task very similarly to adults, although the children took longer to make categorization responses. Decreases in latencies (N2, P3) and amplitudes (P1, N2, P3) with age indicated that categorization processes continue to develop through childhood. P1 latency did not differ between the age groups. N2 latency, which is associated with stimulus categorization, reached adult levels at 9 years and P3 latency at 11 years of age. Age-related amplitude decreases started after the maturational changes in latencies were finished.

Adolescent↗
PubMed1996

Preliminary evidence for a theory of the fractal city.

"In this paper, we argue that the geometry of urban residential development is fractal. Both the degree to which space is filled and the rate at which it is filled follow scaling laws which imply invariance of function, and self-similarity of urban form across scale. These characteristics are captured in population density functions based on inverse power laws whose parameters are fractal dimensions. First we outline the relevant elements of the theory in terms of scaling relations and then we introduce two methods for estimating fractal dimension based on varying the size of cities and the scale at which their form is detected. Exact and statistical estimation techniques are applied to each method respectively generating dimensions which measure the extent and the rate of space filling. These methods are then applied to residential development patterns in six industrial cities in the northeastern United States...."

Americas↗
PubMed1983

A strategy for generating and testing models of migration and urban growth.

"In this paper, it is argued that to identify the appropriate conditions under which the traditional gravity-type migration model should be tested, it is necessary to consider the wider demographic-economic framework in which such models play an essential part. The traditional model and attempts to make it more realistic in an ad hoc way are first sketched, and then the model is embedded in a dynamic framework based on nonlinear differential equations of the logistic kind describing the growth of population and employment. The role of the gravity model in coupling these equations is then developed." A theoretical analysis of this framework is then presented using simulation. "The simplest possible two-region case involving urban and rural regions is developed and after preliminary simulations, a more realistic version involving urban core, suburb and rural hinterland is proposed. A number of variants of this model are tested using simulation and it is concluded that in devising an appropriate test for this type of migration model, attention should be switched from spatial to temporal variation in migration using highly polarized spatial situations such as city regions." (summary in FRE, GER)

Demography↗
PubMed1982

Spatial aggregation in gravity models: 2. One-dimensional population density models.

"This paper, the second of four, is concerned with applying a methodology for analysing the spatial aggregation problem in gravity models outlined in the first paper. The methodology is based on a consistent framework for linking measures of pattern in interaction data to the derivation and estimation of related interaction models using spatial information. In this quest, a link is forged between information in data and the parameters of an associated model.... This relationship can be formalised for the case of the continuous one-dimensional interaction model such as the population density model, and this paper is concerned with demonstrating such an application to aggregations of zones in the Reading [England] region."

Demography↗
PubMed1982

Spatial aggregation in gravity models: 4. Generalisations and large-scale applications.

"This paper is concerned with applying and extending a methodology for analysing spatial aggregation in gravity models developed in three earlier papers to a larger scale and hence more realistic example of spatial interaction than has been treated so far." Seven models are generated and applied to four levels of aggregation of the spatial interaction pattern in Edmonton, Alberta.

Americas↗