Search results for "Spatial"
showing 10 items of 2121 documents
Indeterminacy relations in random dynamics
2007
We analyze various uncertainty measures for spatial diffusion processes. In this manifestly non-quantum setting, we focus on the existence issue of complementary pairs whose joint dispersion measure has strictly positive lower bound.
Modeling the Impact Parameter Dependence of the nPDFs With EKS98 and EPS09 Global Fits
2013
So far the nuclear PDFs (nPDFs) in the global DGLAP fits have been taken to be spatially independent. In this work, using the $A$-dependence of the globally fitted sets EPS09 and EKS98, we have determined the spatial dependence of the nPDFs in terms of powers of the nuclear thickness functions. New spatially dependent nPDF sets EPS09s (NLO, LO, error sets) and EKS98s (LO) are released. As an application, we consider the nuclear modification factor $R_{dAu}^{\pi^0}$ at midrapidity for neutral pion production in deuteron-gold collisions at RHIC in NLO. Comparison with the PHENIX data in different centrality classes is also shown. In addition, predictions for the corresponding nuclear modifica…
Parametric self-trapping in the presence of randomized quasi phase matching
2010
We report on experimental evidence of parametric spatial solitons in a quadratic crystal with randomized periodic ferroelectric poling. Two-color self-focusing via quadratic cascading overcomes the diffractive nature of both fundamental and frequency-doubled beams.
Le marché du travail des scientifiques : capital humain, incitations, proximité
2011
The aim of that thesis is to bring a micro level contribution to the economics of innovation when using original datasets on the French case. Here the manuscript is structured in three chapters: the labour market of scientists and engineers, the incentives for innovation in the private sector and the existence of spatial spillovers in the school to work transition for graduates in science and engineering (S & I). In the first chapter of this thesis, we focus on the labour market for scientists and engineers. First, we identify the different characteristics of this labour market. We then analyze the determinants of access to R & D for young graduates in S & I. Finally, we question more broad…
Mapping inequalities in exclusive breastfeeding in low- and middle-income countries, 2000-2018
2021
Exclusive breastfeeding (EBF)—giving infants only breast-milk for the first 6 months of life—is a component of optimal breastfeeding practices effective in preventing child morbidity and mortality. EBF practices are known to vary by population and comparable subnational estimates of prevalence and progress across low- and middle-income countries (LMICs) are required for planning policy and interventions. Here we present a geospatial analysis of EBF prevalence estimates from 2000 to 2018 across 94 LMICs mapped to policy-relevant administrative units (for example, districts), quantify subnational inequalities and their changes over time, and estimate probabilities of meeting the World Health …
ENVISAT/AATSR derived land surface temperature over a heterogeneous region
2007
Abstract In this paper a method for evaluating land surface temperature (LST) algorithms over heterogeneous areas is presented. The evaluation was made for a set of 12 algorithms derived by using the split-window (SW) and dual-angle (DA) techniques for estimating sea and land surface temperature (SST and LST) from Advanced Along-Track Scanning Radiometer (AATSR) data. A validation of the proposed algorithms was carried out over a heterogeneous region of Morocco in the framework of the WATERMED (WATer use Efficiency in natural vegetation and agricultural areas by Remote sensing in the MEDiterranean basin) project. AATSR data and in situ measurements over this heterogenous region were compare…
Les traces de la vitesse entre réseau et territoire : approche géohistorique de la croissance du réseau ferroviaire français
2016
The interaction between space and network are frequently questioned in the academic literature, by asking the economical and demographical impacts of a new infrastructure, often studied at the scale of a project. This work aims to investigate the components of the interaction in both large spatial and temporal scales. The hypothesis is that the temporal depth and the national scale could bring new explanations. This work is based on the collect, the exploitation and the analysis of the large spatio-temporal database FRANcE (French Railway Network). It identifies all sections of the network since the 19th century and the population census. This database also contains the traces of the speed,…
Spatial distribution of rainfall trends in Sicily (1921–2000)
2006
Abstract The feared global climate change could have important effects on various environmental variables including rainfall in many countries around the world. Changes in precipitation regime directly affect water resources management, agriculture, hydrology and ecosystems. For this reason it is important to investigate the changes in the spatial and temporal rainfall pattern in order to improve water management strategies. In this study a non-parametric statistical method (Mann–Kendall rank correlation method) is employed in order to verify the existence of trend in annual, seasonal and monthly rainfall and the distribution of the rainfall during the year. This test is applied to about 25…
Exploring single polarization X-band weather radar potentials for local meteorological and hydrological applications
2015
Summary The aim of this study is to evaluate the potential use of a low-cost single polarization X-band weather radar, verified by a disdrometer and a dense rain gauge network, installed as a supporting tool for hydrological applications and for monitoring the urban area of Palermo (Italy). Moreover, this study focuses on studying the temporal variability of the Z–R relation for Mediterranean areas. The radar device is provided with an automatic operational ground-clutter filter developed by the producer. Attention has been paid to the development of blending procedures between radar measurements and other auxiliary instruments and to their suitability for both meteorological and hydrologic…
Influence of spatial precipitation sampling on hydrological response at catchment scale
2014
Retrieving precipitation data from raingauge network is a classical and common practice in hydrology and climatology. These data represent the key input in hydrological modeling to reproduce, for example, the characteristics of a flood phenomenon. The accuracy of the model results is strongly dependent on the consistency of the monitoring network in terms of spatial scale, i.e. network density and location of raingauges, and time resolution. In this context, several studies have been carried out to analyze how the rainfall sampling influences the estimation of total runoff volume. The aim of this paper is to use a physically based and distributed-parameter hydrologic model to investigate ho…