Le bilan sénologique : indication et interprétation

Breast cancer is the most common cancer in women in France. The aim of this article is to describe modalities of detection and to explain how the images interpretation and the review are realized.     

A direct fluorescence technique for the rapid detection of sheathed microfilariae in blood smears

Thick and thin blood smears containing microfilariae of Wuchereria bancrofti, Loa loa, Brugia malayi, Brugia pahangi, Brugia patei or Acanthocheilonema vileae were prepared from either cryopreserved blood samples or from freshly collected blood, fixed in methanoi and treated with a fluoresceinated lectin wheat germ agglutinin. Sheathed microfilariae of W. bancrofti, L. loa, B. malayi, B. pahangi and B. patei in the blood smears could be easily detected and counted using a fluorescence assay. The unsheathed microfilaria of Acanthocheilonema viteae did not fluoresce. The possibility of adapting this technique, which does not require the use of parasite specific antibody for the sensitive, parasitological detection offilarial infections, is discussed.     

How bees detect coloured targets using different regions of their compound eyes

Honeybees Apis mellifera detect coloured targets presented to the frontal region of their compound eyes using their colour vision system at larger visual angles (α > 15°), and an achromatic visual system based on the long-wave photoreceptor type at smaller visual angles (5° < α < 15°). Here we examine the capability of the dorsal, ventral and frontal regions of the eye for colour detection. The minimum visual angle α_min at which the bees detect a stimulus providing both chromatic contrast and receptor-specific contrasts to the three receptor types varies for the different regions of the eye: 7.1 ± 0.5° for the ventral region, 8.2 ± 0.6° for the dorsal region and 4.0 ± 0.5° for the frontal region. Flight trajectories show that when the target was presented in the horizontal plane, bees used only the ventral region of their eyes to make their choices. When the targets appeared dorsally, bees used the frontodorsal region. This finding suggests that pure dorsal detection of coloured targets is difficult in this context. Furthermore, α_min in the ventral plane depends on receptor-specific contrasts. The absence of S-receptor contrast does not affect the performance (α_min = 5.9 ± 0.5°), whilst the absence of M- and L-receptor contrast significantly impairs the detection task. Minimal visual angles of 10.3 ± 0.9° and 17.6 ± 3°, respectively, are obtained in these cases. Thus, as for many visual tasks, the compound eye of the honeybee shows a regionalisation of colour detection that might be related to peripheral or central specialisations. Accepted: 28 September 1999     

Background evolution in camouflage systems: A predator-prey/pollinator-flower game

A common predator or anti-predator strategy involves camouflage based on background matching. In some systems, the background is an organism whose fitness is affected by the predator-prey interaction. In these cases, the phenotype of the background species may evolve to affect the degree of background matching in the predator-prey interaction. For example, some flower species (the background) are inhabited by camouflaged ambush predators that attack visiting pollinators. These flowers have a fitness interest in the outcome of the predator-prey interaction because flowers depend on pollinator visitations for reproduction. Therefore, floral colour might evolve relative to predator colour so as to influence the detectability of resident predators. I have created a three-player game, based on Signal Detection Theory, to model the co-evolution of predator and prey/pollinator behavioural strategies with floral colour. This model makes two general predictions: (1) Constraints on predator distributions favour the evolution of flowers that match the predators’ colour because they prevent predators from overexploiting these flowers; (2) factors that produce less discriminating pollinators also favour the evolution of flowers that match the predators’ colour because these pollinators are willing to land on these flowers even if the safety of the flower is in doubt.     

Brain fingerprinting field studies comparing P300-MERMER and P300 brainwave responses in the detection of concealed information

Brain fingerprinting detects concealed information stored in the brain by measuring brainwave responses. We compared P300 and P300-MERMER event-related brain potentials for error rate/accuracy and statistical confidence in four field/real-life studies. 76 tests detected presence or absence of information regarding (1) real-life events including felony crimes; (2) real crimes with substantial consequences (either a judicial outcome, i.e., evidence admitted in court, or a $100,000 reward for beating the test); (3) knowledge unique to FBI agents; and (4) knowledge unique to explosives (EOD/IED) experts. With both P300 and P300-MERMER, error rate was 0 %: determinations were 100 % accurate, no false negatives or false positives; also no indeterminates. Countermeasures had no effect. Median statistical confidence for determinations was 99.9 % with P300-MERMER and 99.6 % with P300. Brain fingerprinting methods and scientific standards for laboratory and field applications are discussed. Major differences in methods that produce different results are identified. Markedly different methods in other studies have produced over 10 times higher error rates and markedly lower statistical confidences than those of these, our previous studies, and independent replications. Data support the hypothesis that accuracy, reliability, and validity depend on following the brain fingerprinting scientific standards outlined herein.     

Development of rRNA and rDNA-targeted probes for fluorescence in situ hybridization to detect Heterosigma akashiwo (Raphidophyceae)

Heterosigma akashiwo (Hada) is a fragile, fish-killing alga. Efforts to understand and prevent blooms due to this harmful species to mitigate the impact on aquaculture require the development of methods for rapid and precise identification and quantification, so that adequate warning of a harmful algal bloom may be given. Here, we report the development and application of rRNA and rDNA-targeted oligonucleotide probes for fluorescence in situ hybridization (FISH) to aid in the detection and enumeration of H. akashiwo. The designed probes were species specific, showing no cross-reactivity with four common HAB causative species: Prorocentrum micans Ehrenberg, P. minimum (Pavillard) Schiller, Alexandrium tarmarense (Lebour) Balech, and Skeletonema costatum (Greville) Cleve, or with four other microalgae, including Gymnodinium sp. Stein, Platy-monas cordiformis (Karter) Korsch, Skeletonema sp.1 Greville and Skeletonema sp.2. The rRNA-targeted probe hybridized to cytoplasmic rRNA, showing strong green fluorescence throughout the whole cell, while cells labeled by rDNA-targeted probe exhibited exclusively fluorescent nucleus. The detection protocols were optimized and could be completed within an hour. For rRNA and rDNA probes, about a corresponding 80% and 70% of targeted cells could be identified and quantified during the whole growth circle, despite the inapparent variability in the average probe reactivity. The established FISH was proved promising for specific, rapid, precise, and quantitative detection of H. akashiwo.     

Variable carbon losses from recurrent fires in drained tropical peatlands

Tropical peatland fires play a significant role in the context of global warming through emissions of substantial amounts of greenhouse gases. However, the state of knowledge on carbon loss from these fires is still poorly developed with few studies reporting the associated mass of peat consumed. Furthermore, spatial and temporal variations in burn depth have not been previously quantified. This study presents the first spatially explicit investigation of fire‐driven tropical peat loss and its variability. An extensive airborne Light Detection and Ranging data set was used to develop a prefire peat surface modelling methodology, enabling the spatially differentiated quantification of burned area depth over the entire burned area. We observe a strong interdependence between burned area depth, fire frequency and distance to drainage canals. For the first time, we show that relative burned area depth decreases over the first four fire events and is constant thereafter. Based on our results, we revise existing peat and carbon loss estimates for recurrent fires in drained tropical peatlands. We suggest values for the dry mass of peat fuel consumed that are 206 t ha⁻¹ for initial fires, reducing to 115 t ha⁻¹ for second, 69 t ha⁻¹ for third and 23 t ha⁻¹ for successive fires, which are 58–7% of the current IPCC Tier 1 default value for all fires. In our study area, this results in carbon losses of 114, 64, 38 and 13 t C ha⁻¹ for first to fourth fires, respectively. Furthermore, we show that with increasing proximity to drainage canals both burned area depth and the probability of recurrent fires increase and present equations explaining burned area depth as a function of distance to drainage canal. This improved knowledge enables a more accurate approach to emissions accounting and will support IPCC Tier 2 reporting of fire emissions.