Nuria Ruiz-Fuentes

Modelling the mean of a doubly stochastic Poisson process by functional data analysis

A new procedure for estimating the mean process of a doubly stochastic Poisson process is introduced. The proposed estimation is based on monotone piecewise cubic interpolation of the sample paths of the mean. In order to estimate the continuous time structure of the mean process functional principal component analysis is applied to its trajectories previously adapted to their functional form. A validation of the estimation method is presented by means of some simulations.

Treatment With Darbepoetin During the First Year After Renal Transplantation: The Starting Point

INTRODUCTION Multiple factors are associated with post-transplantation anemia, and renal function is the main factor. The aims of this study were to compare the evolution of hemoglobin in the first year post-transplantation according to darbepoetin (DA) treatment, and factors related to it, to evaluate the difference between earlier versus delayed treatment, and to describe the dose change pattern. PATIENTS AND METHODS We describe a retrospective study of cohorts in 462 transplant recipients (2004-2011). The variables reported were from donor, transplantation recipient, and DA treatment. RESULTS In this study, 67.5% of patients were treated with DA, 32.5% were not. The comparison of hemoglobin in both groups during the first year showed a similar evolution with significant differences between consecutive measures until the second trimester. The hemoglobin of the treated group was significantly lower. The evolution of renal function was not different. Multivariate analysis related DA treatment to delayed graft function (DGF) and albuminuria in the first year. Patients with early versus delayed DA introduction did not show a difference regarding length of treatment, but the total dose in the delayed introduction was lower. The evolution of creatinine and hemoglobin was similar in both groups. CONCLUSION The introduction of DA was related to DGF and albuminuria. The delayed introduction of DA meant the following: less total dose than earlier introduction, no difference in length of treatment, and a similar evolution in hemoglobin and renal function in both groups. The lack of guidelines about DA treatment in renal transplantation makes it difficult to establish a pattern of dose adjustment.

Renal transplant patient in emergency department.

ue to the growing number of patients with a renal transplant, heir increased life expectancy, and the associated comorbidty, the medical care of such patients in the hospital emergency epartment continues to increase. There is a large variety of onditions that cause such patients to seek medical attention t the emergency department.1–3 The aim of this study was o determine the factors associated with transplant patients’ ttendance at the emergency department in the province of ranada, Spain, to evaluate repeat attendance, and determine he most common reasons for consultation.

El paciente trasplantado renal en urgencias

ue to the growing number of patients with a renal transplant, heir increased life expectancy, and the associated comorbidty, the medical care of such patients in the hospital emergency epartment continues to increase. There is a large variety of onditions that cause such patients to seek medical attention t the emergency department.1–3 The aim of this study was o determine the factors associated with transplant patients’ ttendance at the emergency department in the province of ranada, Spain, to evaluate repeat attendance, and determine he most common reasons for consultation.

Carta al Director: Comunicaciones breves de investigación o experiencias clínicasEl paciente trasplantado renal en urgenciasRenal transplant patient in emergency department

ue to the growing number of patients with a renal transplant, heir increased life expectancy, and the associated comorbidty, the medical care of such patients in the hospital emergency epartment continues to increase. There is a large variety of onditions that cause such patients to seek medical attention t the emergency department.1–3 The aim of this study was o determine the factors associated with transplant patients’ ttendance at the emergency department in the province of ranada, Spain, to evaluate repeat attendance, and determine he most common reasons for consultation.

Generalization of the Wide-Sense Markov Concept to a Widely Linear Processing

In this paper we show that the classical definition and the associated characterizations of wide-sense Markov (WSM) signals are not valid for improper complex signals. For that, we propose an extension of the concept of WSM to a widely linear (WL) setting and the study of new characterizations. Specifically, we introduce a new class of signals, called widely linear Markov (WLM) signals, and we analyze some of their properties based either on second-order properties or on state-space models from a WL processing standpoint. The study is performed in both the forwards and backwards directions of time. Thus, we provide two forwards and backwards Markovian representations for WLM signals. Finally, different estimation recursive algorithms are obtained for these models.

Modeling and Forecasting Monotone Curves by FDA

A new estimation method and forecasting of monotone sample curves is performed from observations in a finite set of time points without a previous transformation of the original data. Monotone spline cubic interpolation is proposed for the reconstruction of the sample curves. Then, the interpolation basis is adapted to apply FPCA and forecasting is done by means of principal components prediction.

Functional Principal Component Modelling of the Intensity of a Doubly Stochastic Poisson Process

An estimator for the intensity process of a doubly stochastic Poisson process is presented, having no statistical previous knowledge of it. In order to give a statistical structure of the intensity, a functional Principal Components Analysis is applied to k estimated sample paths of the intensity built from k observed sample paths of the point process.

On the Coherence Function for Stochastic Systems

A practical implementation of the coherence function for evaluating the linear degree of a stochastic system is developed. It is applied to several well known linear and nonlinear systems.