Search results for "CTAB"
showing 10 items of 231 documents
Dynamics and Predictability of a Heavy Dry-Season Precipitation Event over West Africa—Sensitivity Experiments with a Global Model
2009
Abstract In January 2002 the Cape Verde region in tropical West Africa was hit by an exceptionally heavy precipitation event. Rain rates of up to 116 mm (48 h)−1 caused harmful impacts on the local population. The rainfall was triggered by a series of two upper-level disturbances penetrating from the extratropics to the West African coast. This study investigates the dynamics and predictability of this event on the basis of simulations with the global model Global Model Europe (GME) of the German Weather Service [i.e., Deutscher Wetterdienst (DWD)] initialized by the European Centre for Medium-Range Weather Forecasts (ECMWF) analysis data. Free forecasts satisfactorily reproduce the upper-l…
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…
Sequential analyses in coercive mother-child interaction: the predictability hypothesis in abusive versus nonabusive dyads.
1999
Abstract Objective: A two-fold purpose guided the present study: 1) To test the sequential relationship between the child’s aversive behavior and both the predictability and the compliance episodes, as well as the sequential relationship between these two mothering episodes proposed by the new predictability hypothesis (Wahler, Williams, & Cerezo, 1990) ; 2) to explore whether or not these patterns are specific to these dysfunctional dyads by using a nonabusive comparison group. Method: Fifty mother-child dyads, 25 abusive and 25 nonabusive, participated in this study. Lag sequential analyses were carried out on 302 hours of direct observation, 178 hours in the abusive group, and 124 in the…
Entropic Profiles, Maximal Motifs and the Discovery of Significant Repetitions in Genomic Sequences
2014
The degree of predictability of a sequence can be measured by its entropy and it is closely related to its repetitiveness and compressibility. Entropic profiles are useful tools to study the under- and over-representation of subsequences, providing also information about the scale of each conserved DNA region. On the other hand, compact classes of repetitive motifs, such as maximal motifs, have been proved to be useful for the identification of significant repetitions and for the compression of biological sequences. In this paper we show that there is a relationship between entropic profiles and maximal motifs, and in particular we prove that the former are a subset of the latter. As a furt…
Lists of Spanish sentences with equivalent predictability, phonetic content, length, and frequency of the last word.
2010
This paper presents a pool of Spanish sentences designed for use in cognitive research and speech processing in circumstances in which the effects of context are relevant. These lists of sentences are divided into six lists of 25 equivalent high-predictability sentences and six lists of 25 low-predictability sentences according to the extent to which the last word can be predicted by the preceding context. These lists were also equivalent in phonetic content, length and frequency of the last word. These lists are intended for use in psycholinguistic research with Spanish-speaking listeners.
Information-based detection of nonlinear Granger causality in multivariate processes via a nonuniform embedding technique
2010
We present an approach, framed in information theory, to assess nonlinear causality between the subsystems of a whole stochastic or deterministic dynamical system. The approach follows a sequential procedure for nonuniform embedding of multivariate time series, whereby embedding vectors are built progressively on the basis of a minimization criterion applied to the entropy of the present state of the system conditioned to its past states. A corrected conditional entropy estimator compensating for the biasing effect of single points in the quantized hyperspace is used to guarantee the existence of a minimum entropy rate at which to terminate the procedure. The causal coupling is detected acc…
Impact of a stay in the intensive care unit on the preparation of Advance Directives: Descriptive, exploratory, qualitative study.
2017
Abstract Background Our objective was to assess, through a qualitative, exploratory study, the thought processes of patients regarding the formulation of advance directives (AD) after a stay in the ICU. Methods The study was conducted from May to July 2016 using telephone interviews performed by four senior ICU physicians. Inclusion criteria were: patients discharged from ICU to home > 3 months earlier. Semi-directive interviews with patients focused on 5 main points surrounding AD. Results In total, among 159 eligible patients, data from 94 (59%) were available for analysis. Among all those interviewed, 83.5% had never heard of “advance directives”. Only 2% had executed AD before ICU admis…
Potential predictability of crop impacting climate variables for East Africa and application to sorghum in the Mt Kenya area
2013
In Southern countries with rural low income populations, the vulnerability of rainfed agriculture to rainfall variability requires effective solutions to mitigate the effects of climatic hazards on crops. Predicting the characteristics of rainy seasons some time before they start should help the establishment of agricultural adaptation strategies to rainfall hazards. This is the objective of the present study, focused on East Africa (Kenya and northern Tanzania), and divided in three parts:- Define and document intra-seasonal descriptors (ISD) that will be considered in the predictability study. A new methodological approach has been developed in order to define the onset date (ORS) and the…
A new testing device for the role of the trunk in force production and in balance control in disabled sitting athletes
2017
In cross-country sit-skiing all athletes compete in a sitting position, but some of them have the ability to control their trunk more than others. The trunk plays an essential role in two performance determinants: propulsion generation and balance maintenance. The aim of the study is to design a new testing device assessing athletes’ responses to these propulsion determinants. The new device was composed of a seat surrounded by a sensorized aluminum frame. To assess propulsion generation, two force sensors were mounted in the anterior and posterior side of the frame, while two force sensors were embedded in two ropes elongated from the top of the frame. To measure trunk control, the device …
Complexity traits and synchrony of cryptocurrencies price dynamics
2021
AbstractIn this study, we characterized the dynamics and analyzed the degree of synchronization of the time series of daily closing prices and volumes in US$ of three cryptocurrencies, Bitcoin, Ethereum, and Litecoin, over the period September 1,2015–March 31, 2020. Time series were first mapped into a complex network by the horizontal visibility algorithm in order to revel the structure of their temporal characters and dynamics. Then, the synchrony of the time series was investigated to determine the possibility that the cryptocurrencies under study co-bubble simultaneously. Findings reveal similar complex structures for the three virtual currencies in terms of number and internal composit…