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We have operated upon 588 patients with Klippel and Trenaunay syndrome. The underlying factor is a congenital malformation of the deep veins: agenesis, atresia or compression by fibrovascular bands of the popliteal, femoral or iliac veins. Of these 588 patients, 6 children between 15 months and 4 years of age had severe rectal bleeding and hematuria. One of these children died from massive bleeding of the rectum with septicemia. Another boy was saved by rectal resection and the last one by subtotal cystectomy. The important venogram shows an absence of the anterior venous pathway (superficial femoral vein) compensated by the abnormal development of 2 venous groups, the vein of the sciatic nerve and large veins along the external aspect of the inferior limb. These 2 venous groups penetrate into the pelvis by the sciatic and gluteal notches and terminate in the internal iliac vein which becomes enormous and has a very high flow. This overflow hinders drainage of the venous collateral from the rectum, the bladder and the vagina. The retro adductor vein, prolongated by the deep femoral vein, represents an anastomosis between the sciatic nerve vein and the common femoral vein. The surgeon must try to widen this pathway.

UMR AGAP - équipe AFEF - Architecture et fonctionnement des espèces fruitièresFor oil palm, yield variation is in large part due to variation in the number of harvested bunches. Each successively-produced phytomer carries a female (productive), male or aborted inflorescence. Since phytomer development takes 3–4 years and nearly two phytomers are produced per month, many inflorescences develop in parallel but have different phenological stages. Environment-dependent developmental rate, sex and abortion probability determine bunch productivity, which, in turn, affects other phytomers via source–sink relationships. Water deficit, solar radiation, temperature and day length are considered key external factors driving variation. Their impact is difficult to predict because of system complexity. To address this question we built a simple model (ECOPALM) to simulate the variation in number of harvested bunches. In this model, trophic competition among organs, expressed through a plant-scale index (Ic), drives sex determination and inflorescence abortion during specific sensitive phases at phytomer level. As a supplemental hypothesis, we propose that flowering is affected by photoperiod at phytomer level during a sensitive phase, thus, contributing to seasonal production peaks. The model was used to determine by parameter optimisation the influence of Ic and day length on inflorescence development and the stages at which inflorescences are sensitive to these signals. Parameters were estimated against observation of number of harvested bunches in Ivory Coast using a genetic algorithm. The model was then validated with field observations in Benin and Indonesia. The sensitive phases determined by parameter optimisation agreed with independent experimental evidence, and variation of Ic explained both sex and abortion patterns. Sex determination seemed to coincide with floret meristem individualisation and occurred 29–32 months before bunch harvest. The main abortion stage occurred 10 months before harvest – at the beginning of rapid growth of the inflorescence. Simulation results suggest involvement of photoperiod in the determination of bunch growth dynamics. This study demonstrates that simple modelling approaches can help extracting ecophysiological information from simple field observations on complex systems

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