Search results for " statistica"

A framework for assessing frequency domain causality in physiological time series with instantaneous effects.

2013

We present an approach for the quantification of directional relations in multiple time series exhibiting significant zero-lag interactions. To overcome the limitations of the traditional multivariate autoregressive (MVAR) modelling of multiple series, we introduce an extended MVAR (eMVAR) framework allowing either exclusive consideration of time-lagged effects according to the classic notion of Granger causality, or consideration of combined instantaneous and lagged effects according to an extended causality definition. The spectral representation of the eMVAR model is exploited to derive novel frequency domain causality measures that generalize to the case of instantaneous effects the kno…

A general framework for collecting and analysing the tracking data of cruise passengers at the destination

2016

Cruise passengers’ behaviour at the destination is a rather poorly investigated phenomenon. The single exit/entry point and the relatively brief visiting time, which characterize cruise passengers’ experience at their destinations, make the use of GPS technology particularly suitable for the analysis of such a relevant phenomenon. The aim of this research is to propose a general framework for collecting and analysing GPS tracking data relating to cruise passengers’ behaviour at their destination. The main prerequisites and research stages for the implementation of surveys on cruise passengers will be described and a set of tools and measures for the analysis of GPS tracking data will be pro…

From interval-valued probability assessments to conditional probabilities with quasi additive classes of conditioning events

2005

Using the dglars Package to Estimate a Sparse Generalized Linear Model

2015

dglars is a publicly available R package that implements the method proposed in Augugliaro et al. (J. R. Statist. Soc. B 75(3), 471-498, 2013) developed to study the sparse structure of a generalized linear model (GLM). This method, called dgLARS, is based on a differential geometrical extension of the least angle regression method. The core of the dglars package consists of two algorithms implemented in Fortran 90 to efficiently compute the solution curve. dglars is a publicly available R package that implements the method proposed in Augugliaro et al. (J. R. Statist. Soc. B 75(3), 471-498, 2013) developed to study the sparse structure of a generalized linear model (GLM). This method, call…

Recolonization after habitat restoration leads to decreased genetic variation in populations of a terrestrial orchid.

2012

Colonization is crucial to habitat restoration projects that rely on the spontaneous regeneration of the original vegetation. However, as a previously declining plant species spreads again, the likelihood of founder effects increases through recurrent population founding and associated serial bottlenecks. We related Amplified Fragment Length Polymorphism markers genetic variation and fitness to colonization history for all extant populations of the outcrossing terrestrial orchid Dactylorhiza incarnata in an isolated coastal dune complex. Around 1970, D. incarnata suffered a severe bottleneck yet ultimately persisted and gradually spread throughout the spatially segregated dune slacks, aided…

Factors influencing psychological well-being in patients with Parkinson's disease.

2017

Background Both motor and non-motor symptoms could contribute to significant deterioration of psychological well-being in patients with Parkinson's disease (PD). However, its assessment has been only indirectly evaluated using tools based on health-related quality of life (HRQoL), such as the PDQ-39 scale. Objectives To evaluate psychological well-being in PD using a specific tool of assessment, the Psychological Well-being Scale (PWS), and its clinical correlates. Methods This article reports data of patients' perception of health state, as measured by means of the PWS, from an epidemiological, cross-sectional study conducted in Italian PD patients (FORTE Study). We tested possible relatio…

Factors associated with first- versus second-generation long-acting antipsychotics prescribed under ordinary clinical practice in Italy

2018

Background For many years, long-acting intramuscular (LAI) antipsychotics have been prescribed predominantly to chronic and severe patients, as a last resort when other treatments failed. Recently, a broader and earlier use of LAIs, particularly second-generation LAIs, has been emphasized. To date, few studies attempted to frame how this change in prescribing took place in real-world practice. Therefore, this study aimed to describe the clinical features of patients prescribed with LAIs, and to explore possible prescribing differences between first- and second-generations LAIs under ordinary clinical practice in Italy. Methods The STAR Network "Depot" Study is an observational, longitudinal…

Internal limiting membrane peeling versus no peeling during primary vitrectomy for rhegmatogenous retinal detachment: A systematic review and meta-an…

2018

Background Internal limiting membrane (ILM) peeling during primary vitrectomy for rhegmatogenous retinal detachment (RRD) prevents the formation of postoperative macular epiretinal membrane (ERM). However, studies that compared vitrectomy with and without ILM peeling for RRD, have reported controversial outcomes. Objective To assess the efficacy of ILM peeling versus non-ILM peeling during vitrectomy for RRD by a systematic review and meta-analysis of published studies. Methods PubMed, Medline, Web of Science, Embase databases, and the Cochrane Library were searched up to April 2018 to identify studies that compared primary vitrectomy with and without ILM peeling for RRD with at least six m…

Structural analyses of a hypothetical minimal metabolism

2007

By integrating data from comparative genomics and large-scale deletion studies, we previously proposed a minimal gene set comprising 206 protein-coding genes. To evaluate the consistency of the metabolism encoded by such a minimal genome, we have carried out a series of computational analyses. Firstly, the topology of the minimal metabolism was compared with that of the reconstructed networks from natural bacterial genomes. Secondly, the robustness of the metabolic network was evaluated by simulated mutagenesis and, finally, the stoichiometric consistency was assessed by automatically deriving the steady-state solutions from the reaction set. The results indicated that the proposed minimal …

Clonal Interference and the Evolution of RNA Viruses

1999

In asexual populations, beneficial mutations that occur in different lineages compete with one another. This phenomenon, known as clonal interference, ensures that those beneficial mutations that do achieve fixation are of large effect. Clonal interference also increases the time between fixations, thereby slowing the adaptation of asexual populations. The effects of clonal interference were measured in the asexual RNA virus vesicular stomatitis virus; rates and average effects of beneficial mutations were quantified.