Should we teach linear algebra through geometry?

AbstractCan geometry help students learn linear algebra? I study this question and demonstrate that there is no obvious clear answer: geometry can be an obstacle to learning linear algebra; or it can be helpful. Geometry is helpful only under certain conditions and with a specific use of drawings. These special requirements for using geometry are apparently not much recognized in our teaching of linear algebra courses, at least in France, where my educational studies have taken place

Communication in cancer genetic counselling: does it reflect counselees' previsit needs and preferences?

This study sought to describe counsellor–counselee interaction during initial cancer genetic counselling consultations and to examine whether the communication reflects counselees' previsit needs. A total of 130 consecutive counselees, referred mainly for breast or colon cancer, completed a questionnaire before their first appointment at a genetic clinic. Their visit was videotaped. Counselee and counsellor verbal communications were analysed and initiative to discuss 11 genetics-specific conversational topics was assessed. The content of the visit appeared relatively standard. Overall, counselees had a stronger psychosocial focus than counsellors. Counsellors directed the communication more and initiated the discussion of most of the topics assessed. Counselees did not appear to communicate readily in a manner that reflected their previsit needs. Counsellors provided more psychosocial information to counselees in higher need for emotional support, yet did not enquire more about counselees' specific concerns. New counselees may be helped by receiving more information on the counselling procedure prior to their visit, and may be advised to prepare the visit more thoroughly so as to help them verbalise more their queries during the visit

Het Dyggve-Melchior-Clausen syndroom

The Dyggve-Melchior-Clausen syndrome is a probably autosomal recessively inherited disorder characterized by mental retardation, dwarfism, and skeletal abnormalities especially of the spine, pelvis and hands. It is possibly caused by a disturbance in the protoglycan metabolism. Two Moroccan sibs with this syndrome are described, the first in Dutch literatur

Skin mastocytosis, hearing loss and mental retardation

A girl with skin mastocytosis, hearing loss, microcephaly, mild dysmorphic features and severe mental retardation is described. The symptoms of the child resemble those reported in 1990 by Wolach et al. in another patient sufficiently to suspect the same entity in both. Inheritance may be autosomal recessiv

The velo-cardio-facial (Shprintzen) syndrome. Clinical variability in eight patients

Eight patients (three sporadic, five from two families) with the velo-cardio-facial syndrome (VCFS) or Shprintzen syndrome are reported. Major clinical findings of this syndrome include a characteristic pattern of facial dysmorphisms, cleft palate, cardio-vascular malformations, and (mostly mild-to-moderate) mental retardation or learning difficulties. The syndrome probably is caused by a dominant gene with very variable expression. From previous reports mostly ascertained from cardio-vascular or cleft palate clinics, the incidence of cleft palate and heart defects was calculated to be 98% and 82%, respectively. Out of eight patients of this study who were diagnosed mainly through their pattern of facial dysmorphisms, only two and four had clefts and heart defects, respectively, further demonstrating the variability in the expression of this gene. Similarly, mental retardation, noted in 100% of previous publications, was not present in all of our patients. In two instances, examination of the mother revealed that she probably carried the mutant gene, but that she showed a milder clinical expression than the index patient. It is suggested that careful family investigations should be performed following detection of an index patient, and that the rate of fresh mutations might be not as high as previously assumed