Search results for " and statistics"
showing 10 items of 169 documents
Extending the spectral decomposition of Granger causality to include instantaneous influences: application to the control mechanisms of heart rate va…
2021
Assessing Granger causality (GC) intended as the influence, in terms of reduction of variance of surprise, that a driver variable exerts on a given target, requires a suitable treatment of ‘instantaneous’ effects, i.e. influences due to interactions whose time scale is much faster than the time resolution of the measurements, due to unobserved confounders or insufficient sampling rate that cannot be increased because the mechanism of generation of the variable is inherently slow (e.g. the heartbeat). We exploit a recently proposed framework for the estimation of causal influences in the spectral domain and include instantaneous interactions in the modelling, thus obtaining (i) a novel index…
Oxidative stress is associated with an increased antioxidant defense in elderly subjects: a multilevel approach.
2014
© 2014 Fonseca et al. Background: Studies of associations between plasma GSH-Px activity and cardiovascular risk factors have been done in humans, and contradictory results have been reported. The aim of our study was to assess the association between the scavenger antioxidant enzyme glutathione peroxidase (GSH-Px) activity in plasma and the presence of novel and classical cardiovascular risk factors in elderly patients. Copyright: Methods: We performed a cross-sectional study with baseline data from a subsample of the PREDIMED (PREvención con DIeta MEDiterránea) study in Spain. Participants were 1,060 asymptomatic subjects at high risk for cardiovascular disease (CVD), aged 55 to 80, selec…
La situation de l’artisanat verrier à Augustodunum dans le contexte des découvertes effectuées en Gaule
2007
Il est rappelé d’abord que les cartes de répartition des ateliers de verriers en Gaule, aux premiers siècles de notre ère, écartent de nombreux sites de transformation de verre brut importé du Proche-Orient, au motif qu’on n’y a pas retrouvé de déchets exploitables d’un point de vue typologique. Mais les traces d’activités verrières de cette époque semblent bien plus nombreuses que ne le montrent ces cartes, à l’instar de ce qu’on observe à Autun.Malgré le caractère bien incomplet de nos connaissances sur la répartition des ateliers de verriers anciens de Gaule romaine, cette répartition constitue dès à présent un solide argument en faveur de la prépondérance pour le verre d’un commerce de …
Synergistic Information Transfer in the Global System of Financial Markets.
2020
Uncovering dynamic information flow between stock market indices has been the topic of several studies which exploited the notion of transfer entropy or Granger causality, its linear version. The output of the transfer entropy approach is a directed weighted graph measuring the information about the future state of each target provided by the knowledge of the state of each driving stock market index. In order to go beyond the pairwise description of the information flow, thus looking at higher order informational circuits, here we apply the partial information decomposition to triplets consisting of a pair of driving markets (belonging to America or Europe) and a target market in Asia. Our …
Calculus for the intermediate point associated with a mean value theorem of the integral calculus
2020
Abstract If f, g: [a, b] → are two continuous functions, then there exists a point c ∈ (a, b) such that ∫ a c f ( x ) d x + ( c - a ) g ( c ) = ∫ c b g ( x ) d x + ( b - c ) f ( c ) . \int_a^c {f\left(x \right)} dx + \left({c - a} \right)g\left(c \right) = \int_c^b {g\left(x \right)} dx + \left({b - c} \right)f\left(c \right). In this paper, we study the approaching of the point c towards a, when b approaches a.
Properties of the intermediate point from a mean value theorem of the integral calculus - II
2019
Abstract In this paper we consider two continuous functions f, g : [a, b] → ℝ and we study for these ones, under which circumstances the intermediate point function is four order di erentiable at the point x = a and we calculate its derivative.
The Monocentric Model and After
1998
International audience
Nature et impacts des effets spatiaux sur les valeurs immobilières : le cas de l'espace urbanisé francilien
2013
International audience
The Evolution of Territorial Occupation:
2012
International audience; The analysis of territorial changes over time raises many methodological questions. Despite a very frequent use of spatial analysis methods, few works underline their methodological shortcomings. This paper considers a comparison and discussion of exploratory statistical methods (notably Ripley's K function and its derivatives). It is worth noting three parameters in archaeological spatial analysis: scale, quality and quantity of input data. Archaeological data are intrinsically heterogeneous. Therefore, our approach proposes a multiscalar process integrating heterogeneous data. We describe a range of methods for the description and analysis of heterogeneous spatial …
Expertise et suivi d'une acquisition Lidar pour l'archéologie : l'exemple d'Autun
2014
National audience; Présentation de l'expertise mise en œuvre pour vérifier et valider une campagne d'acquisition de données LiDAR pour des objectifs archéologiques