Biomedical subjects

M J García-Meseguer

Publications and source records attributed to M J García-Meseguer.

6 recordsLinked to original sources

PubMed2003

Mean residence times in linear compartmental systems. Symbolic formulae for their direct evaluation.

A complete analysis has been performed of the mean residence times in linear compartmental systems, closed or open, with or without traps and with zero input. This analysis allows the derivation of explicit and simple general symbolic formulae to obtain the mean residence time in any compartment of any linear compartmental system, closed or open, with or without traps, as well as formulae to evaluate the mean residence time in the entire system like the above situations. The formulae are given as functions of the fractional transfer coefficients between the compartments and, in the case of open systems, they also include the excretion coefficients to the environment from the different compartments. The relationship between the formulae derived and the particular connection properties of the compartments is discussed. Finally, some examples have been solved.

Algorithms↗

PubMed2001

Time course equations of the amount of substance in a linear compartmental system and their computerized derivation.

In this contribution, we present the symbolic time course equations corresponding to a general model of a linear compartmental system, closed or open, with or without traps and with zero input. The steady state equations are obtained easily from the transient phase equations by setting the time --> infinity. Special attention has been given to the open systems, for which an exhaustive kinetic analysis has been developed to obtain important properties. Besides, the results have been particularized to open systems without traps and an alternative expression for the distribution function of exit times has been provided. We have implemented a versatile computer program, that is easy to use and with a user-friendly format of the input of data and the output of results. This computer program allows the user to obtain all the information necessary to derive the symbolic time course equations for closed or open systems as well as for the derivation of the distribution function of exit times.

Computer Simulation↗

PubMed2001

Nursing research in Spain: bibliometrics of references of research papers in the decade 1985-1994.

BACKGROUND: Spain is one of the few European countries to have recently totally incorporated the study of nursing into the university sector. Bibliometric studies may be of a great help for the consolidation of nursing research. AIM OF THE STUDY: The aim of this paper is to describe bibliographic references in Spanish nursing research papers and their evolution over a decade. METHOD: The method consists of a retrospective bibliometric study of a sample (cluster sampling) of 622 research papers (original papers and review papers), which were contained in the Spanish nursing journals Enfermería Científica, Revista ROL de Enfermería, Enfermería Clínica and Enfermería Integral, and published from 1985 to 1994. The journal Nursing Research was selected for qualitative comparative purposes. A series of classic bibliometric indexes were used. RESULTS: The mean of references per paper is 10.64 +/- 10.42; this increased over time (P < 0.001). Review papers have more references (P < 0.001). Price index (percentage of references published during the last 5 years) is 44% and the Insularity (percentage of references published in same country as the article) is 55%. References to journals predominate (58.6%), with a growing tendency for references to Spanish nursing journals, although they are still scarce (18.1% of the references to journals). Spanish is the language of most of the references (60.3%), the second language being English (36.1%). CONCLUSIONS: Bibliographic references in Spanish nursing research papers are scarce and not very specific: this happens both in regard to Nursing Research and to publications in other national and international science areas. However, there is an increasing tendency of references (including references to nursing journals) in the period analysed. The age of the references places Spanish nursing in an intermediate position between the 'hard' sciences and the humanities; and, according to the type of documentation used, we find it halfway between experimental and natural sciences, and technologies and social sciences. There has been a slight increase in references in English in recent years.

Bibliometrics↗

PubMed1995

General linear compartment model with zero input: I. Kinetic equations.

The derivation of kinetic equations is described for n-compartment linear models, in which the substance may be simultaneously introduced into one or more compartments at t = 0 and eliminated from any compartment. For a given zero-input, general formulas are derived which describe the amount of tracer in any of the compartments as a function of time and the model parameters. New algorithms have been developed which allow the expression of the kinetic equations.

Algorithms↗

PubMed1995

General linear compartment model with zero input: III. First passage residence time of enzyme systems.

In this paper, we present an alternative procedure to derive the residence times of enzyme and compartment systems. This procedure allows to express the residence time by a general, symbolic and simplified formula relating it directly with the rate constants. It is applicable to any enzyme reaction scheme which can be formulated as a set of first-order or pseudo-first order interconversions, without any other restriction. A computer program has been developed that greatly facilitates the task of the residence time derivations. The above analysis was extrapolated to any linear compartment model.

Computer Simulation↗

PubMed1995

General linear compartment model with zero input: II. The computerized derivation of the kinetic equations.

The final equations obtained in the first article of this series describing the concentrations of substances in any of the compartments of a model are here cast in an easily programmable form. A computer program with an easy input method and the ability to expand all of the coefficients in the kinetic equations in terms of the model parameters has been developed. The program has been written in the BASIC language.

Computer Simulation↗