The spatial and temporal dimensions of a rural landscape: the Yucatec Maya k'ax

This article presents a case study of rural landscape concepts found in the indigenous Yucatec Maya area of Mexico. Of particular interest in this article is the contrast between the Maya conceptualization of the forest as essential to sustainable agriculture and a Western notion of the forest as the antithesis of agriculture. The former has created a tropical forest that is a product of Maya management and the basis of a sustained Maya society, whereas the latter leads to practices that destroy this forest producing a non-sustainable system. Cyclical landscape processes in the former contrast with linear landscape processes in the latter. In order to compare and contrast the landscapes, a model that identifies embedded concepts is used. It is proposed that the Maya system has an element of verticality and temporality leading to sustainability, a feature lacking in the Western conceptualization.     

Presentational state power: temporal and spatial influences over asylum sector decisionmakers

Previous analyses of forced migration have drawn attention to the increasing discretion held by asylum sector decisionmakers. According to these accounts, as the state reacts to the political risks associated with asylum migration control, responsibility for forced migration management is increasingly transferred onto a range of intermediate actors, between state and society, including local government employees, asylum interviewers, immigration judges and security staff. Yet little research has directly addressed these intermediaries' collective experiences and the influences to which they are subject. The article therefore focuses attention explicitly upon the nominal conduct of this increasingly authorised, discretionary and highly heterogeneous population. Drawing upon 37 interviews across four sites at which asylum sector intermediaries have significant and increasing discretion over asylum seekers' experiences, the findings demonstrate the importance of institutionalised timing and spacing for the determination of their volitional conduct. The timing and spacing of government institutions are important, not only through their influence over asylum seekers directly, but also because they present asylum seekers to those with discretionary authority in ways that are conducive to exclusionary uses of this authority.     

Spatial and temporal effects in Mexican direct elections for the chamber of deputies

By using data of the elections for the Chamber of Deputies of 1997 and 2000 in Mexico, we fit spatial autologistic models with temporal effects to test the significance of spatial and temporal effects on those elections. The binary variable of interest is the one that indicates a win of the National Action Party (PAN) or the alliance that it formed. By spatial effect, we refer to the fact that neighbouring constituencies present dependence on their electoral results. The temporal effect refers to the existence of dependence, for the same constituency, of the result of the election with the result of the previous election. The model that we used to test the significance of spatial and temporal effects is the spatial autologistic model with temporal effects for which estimation is complex and requires simulation techniques. By defining an urban constituency as one that contains at least one population center of 200,000 inhabitants or more, among our principal results, we find that, for the Mexican election of 2000, the spatial effect is significant only when neighbouring constituencies are both urban. For the election of 1997, the spatial effect is significant independent of the type of neighbouring constituencies. The temporal effect is significant on both elections.     

Meteorological influences on the spatial and temporal variability of NO2 in Toronto and Hamilton

The spatial and temporal variability of nitrogen dioxide (NO₂) concentrations and their relationships with meteorology was evaluated in the Toronto–Hamilton urban airshed. NO₂ concentrations were highest in the early morning and late evening. Mean concentrations were highest in winter, although individual one-hour NO₂ concentrations were found to be highest in summer. Wind direction was the strongest control on hourly NO₂ concentration, and temperature and wind speed also had an effect. Our analysis of NO₂ concentration variation by wind direction showed that areas downwind of major highways, urban centres and industry were exposed to higher pollutant concentrations. Seasonal patterns of NO₂ concentration displayed significant spatial heterogeneity, in particular, in Toronto. Onshore winds sheltered coastal inhabitants from the full extent of NO₂ exposure they would otherwise experience. Seasonal variations in meteorology and emissions mean that the degree of spatial variability in NO₂ concentrations changes from season to season. This study will help to improve existing land-use regression-based NO₂ prediction models by incorporating meteorological controls on NO₂ distributions for health effect studies.     

Topographies/topologies of the camp: Auschwitz as a spatial threshold

This paper, largely inspired by Giorgio Agamben’s conceptualization of the camp, reflects on the relationship between the ‘topographical’ and the ‘topological’ in reference to Auschwitz-Birkenau and its spatialities. After having discussed the concept of soglia (threshold), we briefly introduce the ways in which the historiographical literature on the Holocaust treats the relationship between modernity, rationality, and Nazism. The second part of the paper is dedicated to an attempt to read ‘geographically’ the entanglements between the camp, Nazi spatial planning, bureaucratic rationalities, and the Holocaust. The notion of the camp-as-a-spazio-soglia is central to this interpretation. Auschwitz, conceived as a metaphorical and real space of exception, is contextualized within the broader regional geography planned by the Nazis for that part of Poland; while ‘Mexico’, a specific compound within the camp, is described as a key threshold in the reproduction of those very geographies. The aim is to show how the topological spatialities of the camp were a constitutive element of the overall biopolitical Nazi project of ‘protective custody’ and extermination and that, for this reason, they deserve further investigation and need to be discussed in the relation to the crude calculative and topographical aspirations of that same project.     

Guanaco (Lama guanicoe) isotopic ecology in southern South America: spatial and temporal tendencies, and archaeological implications

We synthesize and discuss available isotopic data on Holocene guanaco samples from southern South America, extending from Tierra del Fuego Island to northern Patagonia and the Pampean region. We evaluate temporal and spatial tendencies on the basis of 91 samples (mainly based on δ¹³C_collagen values), presenting implications for paleodietary research in archaeology. We conclude that there are no strong correlations with latitude in the macro-spatial scale, while there is a set of interesting patterns at smaller regional scales. These patterns lead us to evaluate the role of ecologic and topographic variables (e.g. canopy effect, variations in altitude, ecotones) in structuring isotopic variability. Finally, on the basis of the present analysis we suggest a number of hypotheses and perspectives for the use of stable isotopes as geographic tracers of guanaco distribution in the past, and specific implications for the paleodietary study of human samples.     

Spatial and temporal dynamics of the urban heat island effect in a small Brazilian city

This study examined the spatial and temporal patterns of the canopy layer urban heat islands (UHI_UCL) in a small city in southeastern Brazil using the local climate zone (LCZ) system. We analysed the influence of weather conditions, LCZs characteristics, and local surface relief on the UHI_UCL magnitudes. Mobile traverses were used to measure air temperatures during representative nights of wet and dry seasons. Daily maximum magnitudes were observed in compact classes (LCZs 3 and 7) under ideal weather conditions (dry, clear skies, and calm) and higher anthropogenic heat release (weekdays). Seasonal effects on LCZ thermal differences were negligible. The peripheral landscapes were warmer than the city centre in both seasons. Among the warmer areas in the city, magnitudes in compact LCZs 3 and 7 were consistently higher than in LCZ 6. In general, representative sites of the main ‘built’ LCZs in the study area exhibit similar inter-zone temperature patterns to those reported for cities of different sizes from tropical and midlatitude regions. Thermal contrasts of ΔT_{LCZ 3 − D} in the study area reveal significant evidence that small cities can have as strong heat islands as bigger cities. These findings highlight the importance of the LCZ system to identify the main controlling factors driving such thermal differences and the need to extend the application of this approach in other South American cities to yield systematic data of UHI_UCL for urban planning given the coming challenges of climate change over the region.     

Migration and employment change: empirical evidence on the spatial and temporal dimensions of the linkage

"This paper uses a unique set of [U.S.] data to estimate the magnitude of the linkages between employment changes and net employment migration. A simple simultaneous system is specified and estimated for 17 consecutive years. In an average year two extra jobs attract about one additional net migrant, and one additional net migrant has a direct effect on area employment of almost 1.4 jobs." The data are from the One-Percent Social Security Continuous Work History Sample and are for the years 1958 to 1975. The changes in this relationship over time as the economic situation varies are analyzed.     

SANET: A Toolbox for Spatial Analysis on a Network

This article shows a geographical information systems (GIS)-based toolbox for analyzing spatial phenomena that occur on a network (e.g., traffic accidents) or almost along a network (e.g., fast-food stores in a downtown). The toolbox contains 13 tools: random point generation on a network, the Voronoi diagram, the K -function and cross K -function methods, the unconditional and conditional nearest-neighbor distance methods, the Hull model, and preprocessing tools. The article also shows a few actual analyses carried out with these tools.     

Spatial analysis of the coincidence of rare vascular plants and landforms in the Carolinian zone of Canada: implications for protection

Assessing biodiversity in natural landscapes continues to be a focus of attention. While some researchers assess the value of predictive features, such as land‐form, others examine concentrations of rare species, seeking insight into their significance. In this paper I examine two inter‐related concepts. I explore the distributions of rare species on the landscape, assessing correlations between landform, numbers of rare species, and protected areas. I also examine the role of protected sites in maintaining biodiversity. Using records of rare plant collections for the south‐western portion of Ontario (the Carolinian zone) that were compiled as part of the Atlas of Rare Vascular Plants of Ontario project, and combining these with a) a map of the landforms of south‐western Ontario and b) the locations of protected areas within this region, an analysis was made of the spatial coincidence of rare vascular plants, landforms and protected areas. The findings here indicate that protected areas are critically aligned with the distribution of rare vascular plant species. While protected areas occupy less than 2 percent of the study region, approximately 20 percent of the 4379 unique rare plant records analyzed (representing 170 of the 293 rare species in the database or 68%) were collected from a protected site. In addition, while 42 percent of the rare vascular plant records occur on a single landform type, sand plains, sand plains occupy only 18 percent of the region. And while 24 percent of the study region is composed of till plains, less than 2 percent of the rare plant collections were found on this landform. Significantly, four land‐forms, representing 50 percent of the study region, support over 80 percent of all rare plant collections. L'évaluation de biodiversité dans les paysages naturels continue d'être un point de mire. Pendant que certains chercheurs estiment la valeur des caracteristiques prédictives, telles que des formes de relief, d'autres examinent les concentrations d'espèces rares pour comprendre leur signification. Dans cet exposé, j'examine deux concepts intereliés. J'explore les distributions d'espèces rares dans le paysage, évaluant les corrélations entre les formes de relief, les nombres d'espèces rares, et les sites protégés. J'examine aussi le rôle des sites protégés dans la conservation de biodiversité. La coïncidence spatiale des plantes vasculaires rares, formes de relief, et sites protégés a été analysée. L'analyse utilise, en partie, l'inventaire de collections de plantes rares pour une région dans le sud‐ouest de l'Ontario. Cet inventaire a été compilé pour le projet Atlas of Rare Vascular Plants of Ontario. L'analyse totale combine cet inventaire avec (a) une carte des formes de relief dans le sud‐ouest de l'Ontario et (b) les emplacements des sites protégés dans la même région. Les resultats indiquent que les sites protégés sont fortement alignés avec la distribution d'espèces rares. Alors que les sites protégés occupent mains que 2 pour cent de la region étudiée, environ 20 pour cent des 4379 plantes rares uniques analysées (représentant 7 70 des 293 espèces rares dans la banque de données ou 68%) se trouvent sur des sites protégés. De plus, alors que 42 pour cent des plantes rares se retrouvent sur un seul type de forme de relief (plaine de sable), ce type occupe seulement 18 pour cent de la région. Et alors que les plaines constituent 24 pour cent de la région, mains que 2 pour cent des plantes rares se retrouvent sur celles‐ci. Fait révélateur, quatre formes de relief constituent 50 pour cent la région étudiée mais elles soutiennent plus que 80 pour cent des plantes rares.     

Spurios Spatial Regression: Some Monte Carlo Results with a Spatial Unit Root and Spatial Cointegration

In this paper I introduce the concepts of spatial unit roots and spatial cointegration, and via Monte-Carlo simulation I illustrate their implications for spatial regression. It is shown that spatial unit roots lead to spurious (spatial) regression, as in the well-known case involving time-series. Spatial cointegration is similar to its time-series counterpart, although I demonstrate that OLS estimation of spatial error-correction models is not consistent.     

Fluvial spatial taphonomy: a new method for the study of post-depositional processes

Traditional taphonomic analyses do not consider the emergent properties resulting from the relationship of variables. Several of these emergent properties are expressed spatially. Here, we present a spatial taphonomic approach to the understanding of post-depositional processes affecting experimental assemblages modified by fluvial currents. Spatial statistical methods are a great tool to understand how different taphonomic variables relate at a spatial scale. The results of the application of this method to bone assemblages affected by low- and high-energy flows show the loss or modification of most of the original spatial taphonomic relationships. It also shows the degree of bone loss according to element, anatomical section and bone structure, and shape types. Anisotropy is identified in both experimental contexts. These results add new criteria to assess the impact of water flows in bone assemblages and contribute to define the properties of lag assemblages.