RESUMEN
Despite the importance of tetraploid species, most population genetic studies deal with diploid ones because of difficulties in analysing codominant microsatellite data in tetraploid species. We developed a new software program-atetra-which combines both the rigorous method of enumeration for small data sets and Monte Carlo simulations for large ones. We discuss the added value of atetra by comparing its precision, stability and calculation time for different population sizes with those obtained from previous software programs tetrasat and tetra. The influence of the number of simulations on the calculation stability is also investigated. atetra and tetrasat proved to be more precise when compared with tetra, which, however, remains faster. atetra has the same precision than tetrasat, but is much faster, can handle an infinite number of partial heterozygotes and calculates more genetic variables. The more user-friendly interface of atetra reduces possible mistakes.
RESUMEN
Nearly perpendicular magnetic hyperfine fields have been observed for the first time in the Ag "spacers" of Fe/Ag multilayers using low temperature nuclear orientation of (110)Ag(m) at 6 mK. At the same time, vibrating sample magnetometry measurements at temperatures down to 4 K have shown the magnetic anisotropy of the Fe to be in plane. The direction of the Ag hyperfine field is thus noncollinear (nearly orthogonal) to the Fe anisotropy. These results are compared with full potential linearized augmented plane wave calculations using the wien97 code.
RESUMEN
A woman suffering more than ten years with Crohn disease, makes one day a small intestinal obstruction. She undergoes a laparotomy in which a resection of 30 cm terminal ileum is done. Surprisingly the anatomo-pathologic diagnosis is adenocarcinoma between the Crohn's inflammatory lesions. Weedom and Greenstein have proven that Crohn disease and colon carcinoma are related in their follow-ups. But to find such a relationship between Crohn and carcinoma of the small intestine tumours is very small: +/- 0,3/100.000 in a year and so the cases in literature too. We have found 38 cases with enough information. This people with Crohn and carcinoma of the small intestine have an age of 43 years and more than 10 years Crohn symptoms before tumour was found. The tumours are localized in more than 70% in the ileum; 85% are adenocarcinoma. Such differences in localization, age and anatomopathology between Crohn's patients and a normal population let us presume that malign degeneration in Crohn disease is more than accidentally. A casual connection can't be given. For therapeutic use a resection is to prefer because many dysplasias are found in bypass segments.