Search results for "multivariate"

Evolutionary morphology in shape and size of haptoral anchors in 14 Ligophorus spp. (Monogenea: Dactylogyridae).

2017

The search for phylogenetic signal in morphological traits using geometric morphometrics represents a powerful approach to estimate the relative weights of convergence and shared evolutionary history in shaping organismal form. We assessed phylogenetic signal in the form of ventral and dorsal haptoral anchors of 14 species of Ligophorus occurring on grey mullets (Osteichthyes: Mugilidae) from the Mediterranean, the Black Sea and the Sea of Azov. The phylogenetic relationships among these species were mapped onto the morphospaces of shape and size of dorsal and ventral anchors and two different tests were applied to establish whether the spatial positions in the morphospace were dictated by …

Comparative analysis of different techniques for spatial interpolation of rainfall data to create a serially complete monthly time series of precipit…

2011

Abstract The availability of good and reliable rainfall data is fundamental for most hydrological analyses and for the design and management of water resources systems. However, in practice, precipitation records often suffer from missing data values mainly due to malfunctioning of raingauge for specific time periods. This is an important issue in practical hydrology because it affects the continuity of rainfall data and ultimately influences the results of hydrologic studies which use rainfall as input. Many methods to estimate missing rainfall data have been proposed in literature and, among these, most are based on spatial interpolation algorithms. In this paper different spatial interpo…

A multivariate Gompertz-type distribution

2009

Multivariate extensions of the Gompertz distribution are plausible models for the study of several dependent populations with a Gompertz law of growth or multivariate survival data. In this paper we introduce a multivariate distribution with univariate marginal distributions of Gompertz-type form. The new distribution is expressed in closed form and shows symmetry in the component variables. We provide explicit expressions for the first moments which are functions of the Euler constant. Specifically we develop a trivariate Gompertz-type distribution and afterwards consider the multivariate case as an immediate extension of this. The problem of estimating the parameters of the new multivaria…

Clinical Predictors of Immunotolerance in Heart Transplantation

2010

Abstract Background and Aim The drugs routinely administered to prevent rejection often cause lethal side effects. Tolerant patients, therefore, should be identified to minimize these problems. The aim of this analysis was to identify clinical variables that may be associated with tolerance. Methods We recruited 522 heart transplants (HT), excluding combined procedures, retransplantations, pediatric recipients, and subjects who died in the first year to obtain a cohort of 375 patients. Two groups were distinguished by the presence of echocardiographic, clinical, or pathological evidence of rejection in the first year (15 echocardiograms and 10 protocol biopsies per patient); 99 tolerant pat…

Lithosphere Structure, Heat Flow, Gravity, and Other Geoparameters in Central Europe

1991

To clarify structure and evolution of Central European lithosphere, an approach is taken which combines several methods: multivariate statistical data analysis and modelling of data sets, as geology, crustal structure, seismic travel times, heat flow, gravity, geoid heights, topography, vertical motions and unloading affects.

SIMULATION EXPERIMENTS WITH MULTIPLE GROUP LINEAR AND QUADRATIC DISCRIMINANT ANALYSIS

1973

Summary A simulation program is described which can be performed to obtain estimates of the different types of misclassification probabilities for multiple group linear and quadratic discriminant analysis. The program can be used to study how these errors depend on sample sizes and the different parameters of the multivariate normal distribution. Examples for several simulation experiments are given and possible conclusions are discussed.

Computational methodologies in the discovery of inhibitors of HIV-1

2009

Reporting heterogeneity in health: an extended latent class approach

2012

This article explores how individual socio-economic characteristics affect unobserved heterogeneity in self-reporting behaviour and health production using a multivariate finite mixture model. Results show a positive relationship between objective and subjective observable health indicators and true health and support the existence of self-reporting bias related to socio-economic characteristics and individual life styles.

Impact of Circulatory Assistance in the Early Evolution After Heart Transplantation. Unicentric Experience.

2021

ABSTRACT Background Heart transplantation (HT) is the reference treatment for patients with terminal heart failure. In recent years there has been a progressive increase in HT procedures in patients who have a circulatory support (CS). Methods This is a retrospective single-center study of 293 consecutive patients who underwent HT from 2009 to 2018, analyzing the evolution of the 2 cohorts: patients with and without CS as a bridge to HT. Baseline and evolutionary clinical data collected following the usual follow-up protocol were recorded, including clinical events observed during the follow-up 1 year after the procedure. Results The subgroup of patients transplanted with CS showed a higher…

Impact of infectious burden on extent and long-term prognosis of atherosclerosis.

2002

Background — Recent findings suggest a causative role of infections in the pathogenesis of atherosclerosis. In hypothesizing an association between infectious agents and the development of atherosclerosis, we would expect a correlation to the extent of atherosclerosis. Moreover, this effect could be multiplied by the number of pathogens to which an individual had been exposed. Methods and Results — In 572 patients, IgG or IgA antibodies to herpes simplex virus 1 and 2, cytomegalovirus, Epstein-Barr virus, Hemophilus influenzae , Chlamydia pneumoniae , Mycoplasma pneumoniae , and Helicobacter pylori were measured. The extent of atherosclerosis was determined by coronary angiography, carotid…