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Hemimegalencephaly (HME) is a rare neuronal migration anomaly, rarely associated with hemihypertrophy or some other somatic malformation; it can coexist with intracranial arteriovenous shunts which cause cardiac failure. We report a rare case associated with hemihypertrophy of the face, trunk and limbs and malformation of the feet. The neuroradiological findings are underlined and the differential diagnoses discussed.

An efficient technique for partitioning and programming linear algebra algorithms on concurrent architectures is described and applied to 2-D wavefront arrays. The mapping of the computational elements (processes) to processors is based on the concept of folding. The mapping pattern on the 2-D full-size mesh of processes is composition of symmetric tiles of size 2 square root (N)*2 square root (N), N being the number of processors. The algorithm can be partitioned according to a globally sequential, locally parallel scheme. The code optimisation is performed by programming a few different types of tile, according to the algorithm. When the size of the problem is much larger than the size of the mesh of processors, a linear speed-up is achieved independently of the number of processors. Experimental results are presented for matrix multiplication, LU decomposition and the solution of triangular system equations on 2-D meshes of transputers programmed in Occam.

Atrazine is considered a potential contaminant of water bodies, where it has been repeatedly detected. Its use in Italy is almost limited to the Northern part of the country where corn monocultures are common. Northern Italy is characterized by the presence of an area with soil quite permeable and where ground waters are often present at not very deep levels. In this area well waters, which represent the main source of drinking water, have been frequently found contaminated by atrazine. A program has been started aimed at studying the role of soil nature and local factors in the process of groundwater contamination. Two atrazine application rates were used at two sites with loamy and loamy-sandy soils. Results clearly show a different mobility of atrazine in the two soil types. Since the two sites have similar organic carbon levels, the major proportion of clay to sand and the lower pH of loamy soil may explain the lower vertical mobility of atrazine in this soil. Work is in progress to study atrazine behaviour to a soil depth of 30cm and the effect of repeated atrazine applications on ground water pollution.

Fifty rats were injected with 1 ml of 1.5 per cent strontium sulfate in both groin regions, and with 10 mg of 3,4-benzpyrene in the left groin region alone.A reaction of phlogistic productive type was observed in the right region in 15 rats, whereas in 2 animals a tumour occurred on the same side (polymorphocellular sarcoma). This appeared to be histologically different from tumours which developed at the site of benzpyrene injection (fuso- or fusoglobocellular sarcoma).The above observation supports the possibility of a «secondary oncogenesis» at the granuloma site, analogous to that already demonstrated after silicic anhydride administration.

1) A cross experiment has been carried out with primary tumour and granuloma distally located (left groin and right axilla). The existence of the biological phenomenon which is named by the Authors « secondary oncogenesis » is confirmed.2) In this case the statistical incidence of the phenomenon was proved to be lower. This predictable observation would support the presence of a realizing factor. Owing to a higher dispersion due to such experimental conditions, this factor would be fixed in the granuloma in even more sub-liminal doses, sometimes unable to induce oncogenesis.