Search results for "causa."

THE SEMANTIC NETWORK OF THE LATIN PREPOSITION PER: A DIACHRONIC INVESTIGATION

2020

Proponiamo qui i risultati di uno studio corpus-based sugli slittamenti diacronici osservabili nel network semantico della preposizione per in latino. Sulla base della Cognitive Grammar, descriviamo la semantica di per situandola lungo un continuum che procede dal concreto all’astratto, a partire da un contenuto schematico originario; discutiamo, quindi, i percorsi attraverso i quali i nuovi significati astratti emergono attraverso sli ttamenti metonimici, focalizzando la nostra attenzione sui ruoli causali e sulla caratteristica di animatezza.

Assessing complexity and causality in heart period variability through a model-free data-driven multivariate approach

2017

The aim of this study is to emphasize the importance of model-free data-driven mul- tivariate approaches in describing HP variability and cardiovascular control mechanisms responsible for inducing HP changes via modifications of different cardiovascular vari- ables such as SAP and RESP. The goal was achieved through the application, a previously proposed model-free data-driven multivariate framework devised to assess complexity and causality over a multivariate set composed by several, simultaneously recorded, car- diovascular variability series (Porta et al., 2014). The approach was applied to assess the complexity of the cardiac control, through the evaluation of the amount of irregularit…

Assessing connectivity in the presence of instantaneous causality

2014

This chapter is devoted to a discussion of the impact of instantaneous causality on the computation of frequency domain connectivity measures. Instantaneous causality (IC) refers to interactions between two observed time series which occur within the same time lag.

Analytic structure ofϕ4theory using light-by-light sum rules

2013

Abstract We apply a sum rule for the forward light-by-light scattering process within the context of the ϕ 4 quantum field theory. As a consequence of the sum rule a stringent causality criterion is presented and the resulting constraints are studied within a particular resummation of graphs. Such resummation is demonstrated to be consistent with the sum rule to all orders of perturbation theory. We furthermore show the appearance of particular non-perturbative solutions within such approximation to be a necessary requirement of the sum rule. For a range of values of the coupling constant, these solutions manifest themselves as a physical bound state and a K-matrix pole. For another domain …

Linear and nonlinear parametric model identification to assess granger causality in short-term cardiovascular interactions

2008

We assessed directional relationships between short RR interval and systolic arterial pressure (SAP) variability series according to the concept of Granger causality. Causality was quantified as the predictability improvement (PI) of a time series obtained when samples of the other series were used for prediction, i.e. moving from autoregressive (AR) to AR exogenous (ARX) prediction. AR and ARX predictions were performed both by linear and nonlinear parametric models. The PIs of RR given SAP and of SAP given RR, measuring baroreflex and mechanical couplings, were calculated in 15 healthy subjects in the resting supine and upright tilt positions. Using nonlinear models we found a bilateral i…

Causality and the Coulomb sum rule in nuclei.

1989

The spectral function in the Jost-Lehmann-Dyson representation of causal commutators is determined for the nonrelativistic limit of inclusive lepton scattering from nuclei. From this an extrapolation of the Coulomb sum rule to higher-momentum transfers is performed which is consistent with the requirement of causality.

Causality and Localization Operators

2005

The evolution of the expectation values of one and two points scalar field operators and of positive localization operators, generated by an istantaneous point source is non local. Non locality is attributed either to zero point vacuum fluctuations, or to non local operations or to the microcausality principle being no satisfied.

Need of causal analysis for assessing phase relationships in closed loop interacting cardiovascular variability series

2003

The phase spectra obtained by the classical closed loop autoregressive model (2AR) and by an open loop autoregressive model (ARXAR) were compared to shed light on the need of introducing causality in the assessment of the delay between RR and arterial pressure oscillations. The reliability of the two approaches was tested in simulation and real data setting. In simulation, the coupling strength of a bivariate closed loop process was adjusted to obtain a range of working conditions from open to closed loop. In open loop condition, 2AR and ARXAR phases were comparable and in agreement with the imposed delay. In closed loop condition, ARXAR model returned the imposed delays, while 2AR showed a…

Letter by Masè et al Regarding Article, "Granger Causality-Based Analysis for Classification of Fibrillation Mechanisms and Localization of Rotationa…

2020

Causalidad en salud laboral: el caso ardystil

1995

ResumenEl establecimiento de relaciones causa-efecto ha sido y sigue siendo objeto de debate en epidemiología. La naturaleza observacional de la investigación epidemiológica dificulta el reconocimiento de estas relaciones. En este contexto, se han propuesto diferentes modelos para explicar las relaciones causales en los procesos de salud y enfermedad, desde el modelo determinista puro defendido por los postulados de Koch, que requiere la aceptación de relaciones unicausales, pasando por otras explicaciones que asumen la naturaleza multicausal de los problemas de salud en la población. En Salud Laboral se debe disponer también de modelos explicativos y criterios consensuados para valorar las…