Search results for " Spatial"
showing 10 items of 582 documents
Modelling the Impacts of Wildfire on Ash Thickness in a Short‐Term Period
2013
Ash can provide valuable soil protection. However, ash is also very mobile, and soil protection patterns can be quickly changed, favouring the protection of some areas and exposing others with implications for soil erosion. In this research, the effects of a high severity wildfire on ash thickness were studied, 1 and 15 days after the fire. For this evaluation, several interpolation methods were tested to identify the best spatial predictor of ash distribution. The results showed that 1 day after the fire, ash was thinner in high severity areas. Fifteen days after the fire, ash thickness decreased, and the spatial pattern changed. This implies that evaluation of fire severity based on ash t…
Les traces de la vitesse entre réseau et territoire
2017
Les interactions entre transport et territoire sont l’objet d’une littérature scientifique permanente, questionnant les impacts économiques et démographiques d’une nouvelle infrastructure, souvent évoqués à l’échelle d’un projet. Si les études de long terme entre infrastructures de transport et croissance de la population sont nombreuses (Kasraian et al., 2016), les relations sont souvent envisagées à partir de données historiques fragmentées, venant réduire lesfenêtres de temps et d’espaces des analyses (Bretagnolle, 2014).
Ségrégation spatiale, nouvelles approches, nouveaux résultats
2013
International audience
Diffusions, frictions et inégalités spatiales - une introduction
2013
International audience; 2013 n° 38, p. 5‑10.
''Dual'' gravity: Using spatial econometrics to control for multilateral resistance.
2007
We propose a quantity-based `dual' version of the gravity equation that yields an estimating equation with both cross-sectional interdependence and spatially lagged error terms. Such an equation can be concisely estimated using spatial econometric techniques. We illustrate this methodology by applying it to the Canada-U.S. data set used previously, among others, by Anderson and van Wincoop (2003) and Feenstra (2002, 2004). Our key result is to show that controlling directly for spatial interdependence across trade flows, as suggested by theory, significantly reduces border effects because it captures `multilateral resistance'. Using a spatial autoregressive moving average specification, we …
Growth and convergence in Africa: The impact of spatial effects
2010
The aim of this paper is to study the impact of spatial effects on convergence process in Africa over the period 1975-2000. Taking into account these effects through the methodology of Exploratory Spatial Data Analysis (ESDA) and spatial econometrics, we focus on the geographical dimension of economic convergence of African countries. This allows us to deal with spatial autocorrelation which is a consequence of econometric interdependences due to geographic spillovers. Indeed, countries economic performance hides specific geographical patterns providing information on the importance of location on economic dynamics. Our results prove the existence of convergence process in Africa through a …
Social capital formation across space: proximity and trust in European regions
2013
An extensive economics and regional science literature has discussed the importance of social capital for economic growth and development. Yet, what social capital is and how it is formed are elusive issues, which require further investigation. Here, we refer to social capital in terms of “civic” capital and “good culture,” as rephrased by Guiso, Sapienza, and Zingales and Tabellini. The accumulation of this kind of capital allows the emerging of regional informal institutions, which may help explaining differences in regional development. In this article, we take a regional perspective and use exploratory space and space–time methods to assess whether geography, via proximity, contributes…
Comparative Analysis of Spatial Interpolation Methods in the Mediterranean Area: Application to Temperature in Sicily
2015
An exhaustive comparison among different spatial interpolation algorithms was carried out in order to derive annual and monthly air temperature maps for Sicily (Italy). Deterministic, data-driven and geostatistics algorithms were used, in some cases adding the elevation information and other physiographic variables to improve the performance of interpolation techniques and the reconstruction of the air temperature field. The dataset is given by air temperature data coming from 84 stations spread around the island of Sicily. The interpolation algorithms were optimized by using a subset of the available dataset, while the remaining subset was used to validate the results in terms of the accur…
Temperature effects explain continental scale distribution of cyanobacterial toxins
2018
Insight into how environmental change determines the production and distribution of cyanobacterial toxins is necessary for risk assessment. Management guidelines currently focus on hepatotoxins (microcystins). Increasing attention is given to other classes, such as neurotoxins (e.g., anatoxin-a) and cytotoxins (e.g., cylindrospermopsin) due to their potency. Most studies examine the relationship between individual toxin variants and environmental factors, such as nutrients, temperature and light. In summer 2015, we collected samples across Europe to investigate the effect of nutrient and temperature gradients on the variability of toxin production at a continental scale. Direct and indirect…
DISCRIMINATIONS ETHNIQUES DANS L’ACCES AU LOGEMENT: UNE EXPERIMENTATION EN NOUVELLE-CALEDONIE
2016
Dans cette étude, nous mesurons les discriminations dans l’accès au logement dans le GrandNouméa, selon l’origine ethnique, en distinguant les origines kanak et européennes, et selon lequartier de résidence. Entre octobre 2015 et février 2016, nous avons répondu à 342 annonces enprésentant 4 candidats à la location pour chaque annonce, soit 1368 réponses à des annoncesimmobilières. Deux de nos candidats signalent par leur patronyme leur origine kanak, deuxsignalent une origine européenne. Dans chaque paire, un candidat donne un signal de stabilitéfinancière et professionnelle en indiquant explicitement qu’il est fonctionnaire. L’étude consiste àexploiter statistiquement ces données en les c…