Haematological aspects of antenatal diagnosis for thalassaemia in Britain

The results are described of 200 antenatal diagnostic tests for haemoglobinopathies performed on samples of fetal blood obtained during the second trimester of pregnancy. Haemoglobin A synthesis in the fetus was measured by incorporation of tritiated leucine in vitro and separation of the globin chains on CM23 columns. The range of HbA synthesis detected was 3.5-8.0% in normal fetuses, 2.0-5.0% in fetuses with thalassaemia trait, and less than 1.6% in fetuses with thalassaemia major. There were eight cases in which other haemoglobinopathies were diagnosed. 29% of the pregnancies were terminated because thalassaemia major was diagnosed, and 9.5% of the remaining healthy fetuses were lost for obstetric reasons. Follow up has been possible for 96% of the 124 surviving babies and three misdiagnoses have come to light; one false positive (0.5%) and two false negatives (1%). These figures represent a first effort at antenatal diagnosis for haemoglobinopathies and it is likely that they will improve with the passage of time.     

Estimating the stability of N clocks with correlations

Estimation of an atomic clock's frequency stability, separate from its reference, is often done using a three-cornered hat procedure. A major requirement for the success of this method is that clocks be uncorrelated. If this requirement is not satisfied, the three-cornered hat procedure can lead to misleading or even negative variance estimates. Others have considered this problem and developed an analysis that allows for the possibility of cross correlation between clocks. We have extended and applied these ideas to obtain mathematically consistent frequency stability estimates on atomic clock data from the U.S. Naval Observatory. In addition, we derived an expression for the clock weights that produce a minimum variance combination of clocks in the presence of correlations.     

Analysis of correlations, and link and equipment noise in the uncertainties of [UTC - UTC(k)

We refine our estimate of the uncertainty in [UTC - UTC(k)] by taking into account the contribution of correlations between the links. Using a matrix formulation to facilitate computation, we re-analyze the link-based uncertainties and obtain the same solution as found previously. We then evaluate the site-based uncertainties and compare the results with the link-based uncertainties.     

Typology of atoll rims in Tuamotu Archipelago (French Polynesia) at landscape scale using SPOT HRV images

The lagoon of an atoll is separated from the ocean by a rim. As the rim controls the flux of water between ocean and lagoon, its structure is one of the major forcing factors of the biological processes that depend on the renewal rate of lagoonal water. Characterizing rim structure and its degree of hydrodynamic aperture is mandatory for comparing the functioning of different atoll lagoons. This paper characterizes at landscape scale the different types of rims of the atolls of the Tuamotu Archipelago (French Polynesia) using SPOT HRV multi-spectral images. The classification of 117 segments of rims highlights nine different rims. They differ in the relative importance of vegetated, submerged, intertidal and emerged domains. These classes are recognized with accuracy greater than 85% using a simple statistical supervised algorithm. A gradient of hydrodynamic aperture is described, from 0.02% very closed rim exposed to the north, to 0.65% wide open rim exposed to dominant southern swell. We show that most of these nine rims have a preferential exposure. According to the direction of the dominant swell in the Tuamotu region, such exposure may explain the structure of the rims and their degree of hydrodynamic aperture. We discuss the implications of these results for research and management.     

A new way to represent the relative position between areal objects

The fuzzy qualitative evaluation of directional spatial relationships (such as “to the right of”, “to the south of...”) between areal objects often relies on the computation of a histogram of angles, which is considered to provide a good representation of the relative position of an object with regard to another. In this paper, the notion of the histogram of forces is introduced. It generalizes and may supersede the histogram of angles. The objects (2D entities) are handled as longitudinal sections (1D entities), not as points (OD entities). It is thus possible to fully benefit from the power of integral calculus and, so, ensure rapid processing of raster data, as well as of vector data, explicitly considering both angular and metric information     

Multidisciplinary management of hepatocellular carcinoma

BACKGROUND/AIMS: The continuing poor prognosis for patients with hepatocellular carcinoma drives a search for new adjuvant therapies. Targeted locoregional immuno-chemotherapy is one of the most promising. MATERIALS AND METHODS: From 1990 to 1996, 193 patients who were not eligible for liver resection were treated in a prospective randomized study. Ninety-one patients received locoregional targeted chemotherapy only via an arterial catheter (Group A), and 102 received combined locoregional immuno-chemotherapy via two arterial catheters (Group B). RESULTS: Overall survival was significantly different (10.2 months vs 22.3 months), favoring Group B. Complications and side effects of treatment were minimal in Group B and easily handled. Even in Group A, side effects were less severe than effects normally associated with systemic chemotherapy. CONCLUSIONS: Even though the current prognosis for patients with Hepatocellular Carcinoma remains poor, targeted locoregional immuno-chemotherapy has proven to be of benefit in terms of quality of life and survival.