A Micromechanical Sensor of Temperature Based on Surface Plasmons Resonance

in Sensors & Transducers Journal (2008), 96(9), 8-17

This paper reports a new concept of micromechanical sensors of temperature. The sensors consist of a micro-cantilever transducer and optical readout means for monitoring cantilever mechanical response ... [more ▼]

This paper reports a new concept of micromechanical sensors of temperature. The sensors consist of a micro-cantilever transducer and optical readout means for monitoring cantilever mechanical response using the surface plasmons resonance (SPR) phenomenon. This solution has the advantage of reducing the cantilever length due to an ultrahigh resolution of the optical readout means and, therefore a high signal-to-noise ratio can be achieved. [less ▲]

Micrometeorological survey of air-sea ice CO2 fluxes in arctic coastal waters

in Geophysical Research Abstracts (2010), 12(EGU2010-10570),

Micromys minutus (Pallas, 1771) (Mammifère, Rongeur, Muridae), le rat des moissons

in Documents pour un Atlas Zoogéographique du Languedoc-Roussillon (1982)

Microorganisms from Aphid Honeydew Attract and Enhance the Efficacy of Natural Enemies

in Nature Communications (2011), 2

Aphids are one of the most serious pests of crops worldwide, causing major yield and economic losses. To control aphids, natural enemies could be an option but their efficacy is sometimes limited by their ... [more ▼]

Aphids are one of the most serious pests of crops worldwide, causing major yield and economic losses. To control aphids, natural enemies could be an option but their efficacy is sometimes limited by their dispersal in natural environment. Here we report the first isolation of a bacterium from the pea aphid Acyrthosiphon pisum honeydew, Staphylococcus sciuri, which acts as a kairomone enhancing the efficiency of aphid natural enemies. Our findings represent the first case of a host-associated bacterium driving prey location and ovipositional preference for the natural enemy. We show that this bacterium has a key role in tritrophic interactions because it is the direct source of volatiles used to locate prey. Some specific semiochemicals produced by S. sciuri were also identified as significant attractants and ovipositional stimulants. The use of this host-associated bacterium could certainly provide a novel approach to control aphids in field and greenhouse systems. [less ▲]

Microorganisms from aphid honeydew attract natural enemies and tending ants

Conference (2011, August)

Aphids are some of the most serious pests of cultivated crops worldwide, causing major yield and economic losses. Previous works have demonstrated ants and natural enemies (including ladybeetles and ... [more ▼]

Aphids are some of the most serious pests of cultivated crops worldwide, causing major yield and economic losses. Previous works have demonstrated ants and natural enemies (including ladybeetles and hoverflies) to be able to use aphid volatile chemicals to locate aphid colonies. Here, we report the first isolation of a bacterium from the pea aphid Acyrthosiphon pisum honeydew, Staphylococcus sciuri, which produces kairomones used by the aphidophagous hoverfly Episyrphus balteatus and the Asian Ladybeetle Harmonia axyridis during their search for prey colonies. Some specific semiochemicals produced by S. sciuri were identified as attractants and ovipositional stimulants. Similarly, we have shown scouts of the aphid tending ant species, Lasius niger, to orientate their foraging behaviour toward an Aphis fabae infested plant and we have demonstrated that the odours released by this aphid honeydew were attractive for ant scouts. Again, bacteria were involved in the production of these honeydew semiochemicals. Interestingly, ant scouts were also able to discriminate honeydew odour from A. fabae (usually attended by L. niger) and A. pisum (unattendedby L. niger). Comparison of the volatile and bacteria composition of both aphid species honeydew were attended. [less ▲]

Microorganisms in Karsts: a case study in St Anne cave, Belgium

Poster (2011, September 30)

Despite the importance of microorganisms as geochemical agents over geological times, their extended metabolic diversity and their essential role in element cycles (i.e. mineral dissolution, precipitation ... [more ▼]

Despite the importance of microorganisms as geochemical agents over geological times, their extended metabolic diversity and their essential role in element cycles (i.e. mineral dissolution, precipitation, oxido-reduction processes), microbial community composition and processes as well as their ecological role in karst environments are poorly known. While little was published on cave-dwelling microorganisms until the early 1990s, it is now recognized that microorganisms may mediate many important mineral transformations, originally considered to be inorganic in nature. Indeed, recent evidence (Northup & Lavoie, 2001) proved the implication of microorganisms in karstification through precipitation and dissolution processes, resulting in the deposition of carbonate speleothems, silicates, iron or manganese oxides, sulphur compounds and nitrates and in the breakdown of limestone walls. In this poster, we review some potential processes and signs of microbial activity in caves. We present results of a study on the microbial diversity in the ‘St Anne’ cave, Belgium. We focused on ammonia-oxidizing bacteria (AOB), which are responsible for the first, acidifying step of the nitrification process. Chemical composition of the water, numbers of cultivable bacteria (free and particle-associated bacteria) and the diversity of AOB were studied in waters and sediments of the ‘Chawresse’ (underground river in St Anne), on the cave wall and in the soil aboveground. The use of molecular techniques, based on direct ADN extractions, provide more detailed information on the microbial diversity of an environment, as culture-based techniques retrieve only about 1% of bacterial species present in the environment. Bacterial counts showed that most cultivable bacteria were associated with suspended particles and that their numbers decreased underground. Molecular analyses revealed the presence of AOB in the karst system. Comparison of aboveground and belowground diversity also indicated the possibility of a specific endokarst AOB community. Further research perspectives will be discussed. <br /> <br /> <br />Northup, D.E. and Lavoie, K.H. 2001. Geomicrobiology of caves: A review. Geomicrobiology Journal, 18(3):199-220. [less ▲]

Micropapules paroxysmales prurigineuses tronculaires.

in Dermatologie Actualité (2011), 127

MicroPET Focus 120 scanner use at high-­‐count rate

Poster (2012, September)

Kinetic modeling of physiological processes using imaging techniques requires an accurate measurement of the time-activity curve of the tracer in plasma, known as the arterial input function (IF). The IF ... [more ▼]

Kinetic modeling of physiological processes using imaging techniques requires an accurate measurement of the time-activity curve of the tracer in plasma, known as the arterial input function (IF). The IF can be obtained by manual blood sampling, can be derived from PET images, or continuously measured by the use of small counting systems such as beta microprobes [1]. However, some beta microprobe systems can suffering from high background counts and low sensitivity compared to PET can obligate the use of activities higher than those typical for the imaging system. In the present study, the NEMA NU4-2008 image quality (IQ) phantom [2] was used to evaluate the image quality of the microPET Focus 120 at high activity values. Attenuation correction was obtained from transmission measurement using 57Co point source. Eight emission scans of 20 minutes were performed at decreasing activity starting from 109 MBq to 3.7 MBq (total activity in the field-of-view). To study the effect of normalization in high count rate studies, several normalization scans were performed using activities ranging between 18 and 212 MBq. Images were reconstructed with all corrections using Fourier rebinning and filtered backprojection. The mean activity and the coefficients of variation of the uniform slices were measured. All high activity reconstructed images showed a detector-block-patterned artifact with an overestimation of the counts when normalization activity is higher than that used in the IQ phantom and underestimation of the counts when normalization activity is below the activity used in the IQ phantom. Using the same high activity for acquisition and normalization considerably reduces the patterned-artifact but does not eliminate it entirely. The observed artifact is due to pulse pile-up in the detectors at high count-rates. A dedicated rejection of the pulse pile-up does not appear to have been implemented for the microPET Focus 120. An alternative would be to re-calibrate the detectors with higher activity values to prevent any pile-up effect or to create an attenuation volume into which phantoms or small animals could be inserted thus decreasing the artifact. This latter option is under development. References: [1] G. Warnock et al, European Journal of Nuclear Medicine and Molecular Imaging Research, 1-13 (2011) [2] NEMA Standards Publication NU4-2008. Rosslyn, VA: National Electrical Manufacturers Association; (2008). [less ▲]

Microphone arrays fundamentals

Conference (2011, November 23)

Microphone arrays are essentially directional sensors. They are therefore mainly used for locating, identifying, isolating, measuring and recording individual sound sources. The main principles governing ... [more ▼]

Microphone arrays are essentially directional sensors. They are therefore mainly used for locating, identifying, isolating, measuring and recording individual sound sources. The main principles governing the directivity of microphone arrays are reviewed: phase differences between signals create constructive and destructive interferences, depending on the direction of the sound source. Moreover, signal processing is applied to provide “beamforming”, i.e. beam shaping and steering. Contrary to continuous antenna, discrete arrays can create aliasing, which can result in false detections of sound sources. The delay-and-sum and filter-and-sum beamformers are described. Finally, as simple beamformers are often frequency dependent, some solutions to obtain constant (broad-band) directivity are presented. [less ▲]

MICROPOLLUTANTS ISSUES: A MODELLING STUDY OF HEAVY METALS WITHIN TWO FRENCH BASINS AND A TEST APPLICATION TO COCAINE IN BELGIUM

Poster (2010, April)

European policies (European Framework Directive: Water 2000/60/CE, Directive 76/464/CE) impose to reduce the releases of about a hundred substances in surface water. In the last years, the AQUAPOLE has ... [more ▼]

European policies (European Framework Directive: Water 2000/60/CE, Directive 76/464/CE) impose to reduce the releases of about a hundred substances in surface water. In the last years, the AQUAPOLE has been involved in two studies related to this matter. First, on the request and with the financial support of both the French Ministry of Environment and ONEMA (“Office National de l’Eau et des Milieux Aquatiques”), INERIS (“Institut National de l’Environnement Industriel et des Risques”) drew up the guidelines of a methodology allowing fixing the local Limit Values to Emission so as to abide by the quality standards on the whole watershed. Within this context, INERIS wishes to test the use of pollutant transfer models on pilot sub-basins. The PEGASE model has been used to simulate micropollutants on two concrete use cases (1): (iii) in the Meuse sub-basin, managed by the French Water Agency Rhine-Meuse, for simulations concerning cadmium and zinc; (iv) in the Adour sub-basin, managed by the French Water Agency Adour-Garonne, for simulations applied to cadmium and copper. The choice of each substances and sub-basins was made by mutual agreement between INERIS, the concerned Water Agencies, and the AQUAPOLE. A major selection criterion for the substances and the sub-basins was the availability of data (sources and in situ measurements). For the second study, the PEGASE model has been adapted to describe the cocaine’s behaviour (using a stable metabolite of the cocaine in the environment: the benzoylecgonine (BZE)) in waste water, waste water treatment plants (WWTP) and surface water (2). The cocaine is newly described in the model as an additional micropollutant (PEGASE already treats numerous heavy metals), thanks to the implementation of new state variable equations and their specific parameterizations. Simulations of BZE have been done in the Walloon and Flemish regions, where many measurements from the COWAT project (3) were available. The first results are showing good agreement between calculated and measured values. The ability of the model to simulate the fate of studied micropollutants (cadmium, zinc, copper, and the cocaine derivatives) in surface waters should be enhanced and extended to other substances and basins. Moreover, additional data still have to be collected and measured. [less ▲]