Sur les possibilités d'application de la théorie du filtrage optimum à la conception de chaînes détectrices de précision pour spectrométrie nucléaire

The authors try to find a new method for deriving low noise detector amplifiers. Wiener optimum filtering allows them to compute the electrical characteristics of a " linear filtering stage ". The low theoretical noise level shows that the use of Wiener filtering can improve the accuracy of nuclear spectrometry. The main problem is the practical construction of a Wiener filter. Using a half sine wave as input signal, it appears that the filter synthesis is near that of a wide band with tuned circuit. An approach to a Wiener filter can be made using high frequency transformers.On recherche une nouvelle méthode de calcul des amplificateurs à faible bruit pour détecteurs. Le filtrage optimum de Wiener permet de calculer les caractéristiques électriques d'un étage « filtrage linéaire ». Le faible niveau de bruit, calculé théoriquement, montre que l'emploi du filtrage de Wiener peut améliorer la précision de la spectrométrie nucléaire. Le problème principal est la synthèse pratique d'un filtre de Wiener. En employant comme signal d'entrée une demi-sinusoïde, il apparaît que la synthèse est proche de celle d'un circuit accordé à large bande. L'emploi des transformateurs haute fréquence permet une synthèse approchée d'un tel filtre

ETUDE DES REACTIONS (p, d) AVEC UN FAISCEAU DE PROTONS POLARISES

Les sections efficaces différentielles et les asymétries ont été mesurées pour des réactions (p, d) sur 49Ti 57Fe, 91Zr, 118Sn et 119Sn. Ces expériences jointes à des expériences précédentes sur 48Ca, 53Cr, 61Ni et 90Zr montrent la forte dépendance en j des asymétries mesurées. La D.W.B.A. est généralement en bon accord avec l'expérience.Differential cross-sections and asymmetries were measured for (p, d) reactions on 49Ti, 57Fe, 91Zr, 118Sn and 119Sn. These experiments, added to previous (p, d) experiments on 53Cr, 61Ni, 90Zr, show a strong j dependence of the measured asymmetries. The D.W.B.A. generally gives a good agreement for both cross-sections and asymmetries

Conductrices d’hémophilie : expérience d’un CHRU en France

International audienceOBJECTIVES:To report the management of carriers of haemophilia in a French university hospital and assess different issues of these patients.PATIENTS AND METHODS:Retrospective study of the carriers of haemophilia who consulted at the university hospital of Montpellier, France, between 1995 and 2011. Information were obtained from medical records and from a questionnaire sent to carriers. We recorded data about biological characteristics, bleeding tendency and management of pregnancies.RESULTS:Sixty-four carriers of haemophilia A or B were included. Their median FVIII or FIX level was 52 % (range, 15-137 %). Menstrual bleeding lasted more than 7 days in 31 % of carriers. A total of 142 pregnancies started in 54 carriers, and 101 resulted in live births with 26 boys with haemophilia. Sixty-two prenatal diagnoses carried out, 15 have terminated their pregnancy because of a hemophiliac male fetus. Seventy-six percent of deliveries were vaginal delivery and 49 % took place in a level-3 maternity. There were 10.8 % and 8.5 % primary and secondary post-partum hemorrhage, respectively.CONCLUSION:The risk of bleeding among carriers of haemophilia is associated with their antihemophilic factor level. To improve the management of carriers, a multidisciplinary and standardized medical record, with a specific questionnaire to evaluate bleedings, could be considered. A regional register that lists all carriers, regardless of their antihemophilic factor level, would also be useful