Balance-dendrogram. A new routine of CoDaPack

A statistical analysis of compositional data based on the Aitchison geometry of the simplex requires an appropriate basis for representing the data. A simple and intuitive way of building such a basis employs a sequential binary partition of the compositional vector. The partition, together with some statistical summaries of the coordinates, or balances, can be represented in a dendrogram-type graph. In this paper we introduce an implementation of this methodology inside CoDaPack, which is freeware. An example with real data illustrates the use of the Balance-Dendrogram routine.     

The myopic intraocular lens in a phakic eye. Initial experience

The very first experiences with implantation of 3 phakic anterior chamber lenses for high myopia correction are presented. After average 4 month follow up good stability and transparation of concave lenses type ZB5M were observed with accurately achieved correction postoperatively.     

Programs of early detection of breast cancer and access of mammography in Spain

BACKGROUND: We studied availability to mammography among Spanish women aged 40 to 70 years, variation in use of the mammography by autonomous community, and the situation and importance of breast cancer screening programs among other factors, in the access to mammography. SUBJECTS AND METHODS: A cross-sectional population survey was conducted in 1994 in a sample of 3,218 women. A questionnaire was used to collect data on the variable access (receipt of at least one mammogram in the last 2 years) as well as different access-related variables. Information on breast cancer screening programs was collected by contacting the responsible institutions. We considered that a program had total coverage if it included all the municipalities in the province and partial if it did not include all municipalities. RESULTS: Twenty-eight percent of women had performed a mammogram. This proportion varied among autonomous communities (AACC) from 11.5 to 73.8%. Breast cancer screening programs existed in 8 AACC. The multivariant analysis revealed an association between access to mammography and the existence of a screening program, especially when the later had total coverage (OR = 7.64; 95% CI = 5.24-11.10). An association was also found between access to mammography and physician-related factors, place of residence and attitudes of women toward mammography. CONCLUSIONS: Less than one third of women aged 40-70 have performed a mammography in the last 2 years, and this proportion varies among AACC. Gynecologist visits and the existence of breast cancer screening programs are fundamental factors in the access to mammography in Spain.     

Embryonal metabolism

It is very difficult to have a clear and homogeneous idea of the embryo metabolism. In fact it may vary from one species to another and also according to the embryonic stage: i.e. before and after genomic activation. Basic compounds such as glucose may be toxic, but obviously, it is more the problem of the quantity introduced in the culture media and an unsuitable balance between the metabolites which may impair the embryonic development. At low concentration glucose is actively metabolised by embryos. High levels of amino acids are deleterious (due to release of ammonia), but they are necessary at low concentrations. Addition of serum or other biological fluids is generally useless. Further knowledge on embryo metabolism is necessary to avoid culture medium related delay or developmental blocks. Sequential media are at least partly the answer.     

pH control of the condensation reaction and its effect on the properties of formaldehyde/urea resins

The conditions of the preparation of formaldehyde/urea (F/U) resins have been supervised with the aim to reduce formaldehyde emission by influencing the ratio of methylene/dimethylene-ether-bridge linkages in the product. The most crucial point of this task is to keep the pH values of the reacting mixtures on the required level. The effect of formic acid, unevitably present in industrial formaldehyde solutions, was neutralized by applying a new buffer system, containing boric acid and ethylene glycol.     

Effects of Ajoene on lymphocyte and macrophage membrane-dependent functions

An increasing flow of evidences collected on elementary forms of learning processes in selected animal models evidentiates some mechanisms which can represent the basic cellular principles underlying plastic changes: 1. 5HT and second messengers of nucleotide type (like cAMP) have a pivotal role in the learning process. 2. In almost all short-term learning processes the modifications are subserved by a mechanism of protein phosphorylation. 3. In various animal models the modulation of K+ and Ca2+ channels is the molecular mechanism for learning. Experiments performed in sensory T neuron of the leech indicate that the modulation of Na+/K+ electrogenic pump is one of the fundamental mechanism for learning. 4. In long-term plastic changes, the most important finding is that newly synthesized proteins are formed. 5. In addition to what has been observed in the Aplysia model, where changes in synaptic efficacy represent the basic principles of memory storage, in the leech it has been demonstrated that a molecular machinery present in a single neuron can adapt the activity of the cell to environmental stimuli.