Differences in citation frequency of clinical and basic science papers in cardiovascular research

In this article, a critical analysis is performed on differences in citation frequency of basic and clinical cardiovascular papers. It appears that the latter papers are cited at about 40% higher frequency. The differences between the largest number of citations of the most cited papers are even larger. It is also demonstrated that the groups of clinical and basic cardiovascular papers are also heterogeneous concerning citation frequency. It is concluded that none of the existing citation indicators appreciates these differences. At this moment these indicators should not be used for quality assessment of individual scientists and scientific niches with small numbers of scientists

Bibliometric data in clinical cardiology revisited. The case of 37 Dutch professors

In this paper, we assess the bibliometric parameters of 37 Dutch professors in clinical cardiology. Those are the Hirsch index (h-index) based on all papers, the h-index based on first authored papers, the number of papers, the number of citations and the citations per paper. A top 10 for each of the five parameters was compiled. In theory, the same 10 professors might appear in each of these top 10s. Alternatively, each of the 37 professors under assessment could appear one or more times. In practice, we found 22 out of these 37 professors in the 5 top 10s. Thus, there is no golden parameter. In addition, there is too much inhomogeneity in citation characteristics even within a relatively homogeneous group of clinical cardiologists. Therefore, citation analysis should be applied with great care in science policy. This is even more important when different fields of medicine are compared in university medical centres. It may be possible to develop better parameters in the future, but the present ones are simply not good enough. Also, we observed a quite remarkable explosion of publications per author which can, paradoxical as it may sound, probably not be interpreted as an increase in productivity of scientists, but as the effect of an increase in the number of co-authors and the strategic effect of networks

Towards a new crown indicator: an empirical analysis

We present an empirical comparison between two normalization mechanisms for citation-based indicators of research performance. These mechanisms aim to normalize citation counts for the field and the year in which a publication was published. One mechanism is applied in the current so-called crown indicator of our institute. The other mechanism is applied in the new crown indicator that our institute is currently exploring. We find that at high aggregation levels, such as at the level of large research institutions or at the level of countries, the differences between the two mechanisms are very small. At lower aggregation levels, such as at the level of research groups or at the level of journals, the differences between the two mechanisms are somewhat larger. We pay special attention to the way in which recent publications are handled. These publications typically have very low citation counts and should therefore be handled with special care

A theoretical analysis of nonsteady-state oxygen transfer in layers of hemoglobin solution

The oxygenation of layers of hemoglobin solutions thick enough to ensure chemical equilibrium between oxygen and hemoglobin has been analyzed theoretically assuming simultaneous diffusion of oxygen and oxyhemoglobin. The dimensionless transfer equation was solved for the finite and semi-infinite situation, the parameters being 1) the ratio of bound to physically dissolved oxygen after equilibration (H), 2) the ratio of carrier-mediated to free oxygen flux at steady state (D), and 3) the dimensionless saturation curve (characterized by phi 50). A parametric analysis provided plots of the dimensionless oxygenation time against these three dimensionless parameters. In this way, from the oxygenation times plotted as a function of the reciprocal oxygen driving pressure in any particular hemoglobin solution, the values of the oxygen permeability (or, knowing oxygen solubility, of the oxygen diffusion coefficient) and of the hemoglobin diffusion coefficient can be derived simultaneousl

Use of a wedge cuvette in this layer photometry and its application to oximetry

A wedge cuvette was constructed by fixing 2 glass plates at a known angle with a spacer at one end. This resulted in a thin layer with thickness varying from 0 to 250 micrometer. By measuring the intensity of a beam of light through the thin layer as a function of distance along the wedge (and thus layer thickness), the absorption coefficient at the light wavelength used could be obtained without a separate measurement of I0, the reference light intensity. In addition, the difficult problem of determining accurate layer thickness as encoutered in conventional thin layer photometry has been avoided. Tests of the wedge cuvette method with Evans Blue and Malachite Green serial dilutions as well as with haemoglobin solutions at several oxygen saturations demonstrate that accuracy of the order of 1% can be obtained. Application of the wedge cuvette in experiments on oxygen uptake by layers of haemoglobin solution are discusse