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Sample records for etude rimed rayonnements

  1. Learning Words with Common Rimes.

    ERIC Educational Resources Information Center

    Dwyer, Edward J.

    An extensive research review by M. Adams (1990) led her to the conclusion that providing instruction and reinforcement in learning common rimes is highly beneficial in fostering growth in learning to read. While substantial amounts of reading, either independent or with partners, is critical in learning words with common rimes, focused study is…

  2. Growth of ice particle mass and projected area during riming

    NASA Astrophysics Data System (ADS)

    Erfani, Ehsan; Mitchell, David L.

    2017-01-01

    There is a long-standing challenge in cloud and climate models to simulate the process of ice particle riming realistically, partly due to the unrealistic parameterization of the growth of ice particle mass (m) and projected area (A) during riming. This study addresses this problem, utilizing ground-based measurements of m and ice particle maximum dimension (D) as well as theory to formulate simple expressions describing the dependence of m and A on riming. It was observed that β in the m - D power law m = α Dβ appears independent of riming during the phase 1 (before the formation of graupel), with α accounting for the ice particle mass increase due to riming. This semi-empirical approach accounts for the degree of riming and renders a gradual and smooth ice particle growth process from unrimed ice particles to graupel, and thus avoids discontinuities in m and A during accretional growth. Once the graupel with quasi-spherical shape forms, D increases with an increase in m and A (phase 2 of riming). The treatment for riming is explicit, and includes the parameterization of the ice crystal-cloud droplet collision efficiency (Ec) for hexagonal columns and plates using hydrodynamic theory. In particular, Ec for cloud droplet diameters less than 10 µm are estimated, and under some conditions observed in mixed-phase clouds, these droplets can account for roughly half of the mass growth rate from riming. These physically meaningful yet simple methods can be used in models to improve the riming process.

  3. Rime Mushrooms - Extreme Rime Ice Buildup on Mountain Summits of Southern Patagonia

    NASA Astrophysics Data System (ADS)

    Whiteman, C. D.

    2015-12-01

    The Southern Patagonian Andes are known among mountain climbers for a meteorological phenomenon that occurs there but is unknown in many other mountain areas. The phenomenon is the buildup of rime ice in large bulbous or mushroom-shaped accretions on the windward side of projecting mountain summits, ridges and exposed near-vertical rock faces. These "ice mushrooms" have never been investigated scientifically. This talk will introduce the audience to ice mushrooms, describe where they are found, consider the meteorological factors leading to their formation, and illustrate how they are negotiated by mountain climbers using photographs and descriptions from Southern Patagonia.

  4. Insights into riming and aggregation processes as revealed by aircraft, radar, and disdrometer observations for a 27 April 2011 widespread precipitation event: Insights into Riming and Aggregation

    SciTech Connect

    Giangrande, Scott E.; Toto, Tami; Bansemer, Aaron; Kumjian, Matthew R.; Mishra, Subhashree

    2016-05-19

    Our study presents aircraft spiral ascent and descent observations intercepting a transition to riming processes during widespread stratiform precipitation. The sequence is documented using collocated scanning and profiling radar, including longer-wavelength dual polarization measurements and shorter-wavelength Doppler spectra. Riming regions are supported using aircraft measurements recording elevated liquid water concentrations, spherical particle shapes, and saturation with respect to water. Profiling cloud radar observations indicate riming regions during the event as having increasing particle fall speeds, rapid time-height changes, and bimodalities in Doppler spectra. These particular riming signatures are coupled to scanning dual polarization radar observations of higher differential reflectivity (ZDR) aloft. Moreover, reduced melting layer enhancements and delayed radar bright-band signatures in the column are also observed during riming periods, most notably with the profiling radar observations. The bimodal cloud radar Doppler spectra captured near riming zones indicate two time-height spectral ice peaks, one rimed particle peak, and one peak associated with pristine ice needle generation and/or growth between -4°C and -7°C also sampled by aircraft probes. We observe this pristine needle population near the rimed particle region which gives a partial explanation for the enhanced ZDR. The riming signatures aloft and radar measurements within the melting level are weakly lag correlated (r~0.6) with smaller median drop sizes at the surface, as compared with later times when aggregation of larger particle sizes was believed dominant.

  5. Insights into riming and aggregation processes as revealed by aircraft, radar, and disdrometer observations for a 27 April 2011 widespread precipitation event: Insights into Riming and Aggregation

    DOE PAGES

    Giangrande, Scott E.; Toto, Tami; Bansemer, Aaron; ...

    2016-05-19

    Our study presents aircraft spiral ascent and descent observations intercepting a transition to riming processes during widespread stratiform precipitation. The sequence is documented using collocated scanning and profiling radar, including longer-wavelength dual polarization measurements and shorter-wavelength Doppler spectra. Riming regions are supported using aircraft measurements recording elevated liquid water concentrations, spherical particle shapes, and saturation with respect to water. Profiling cloud radar observations indicate riming regions during the event as having increasing particle fall speeds, rapid time-height changes, and bimodalities in Doppler spectra. These particular riming signatures are coupled to scanning dual polarization radar observations of higher differential reflectivity (ZDR)more » aloft. Moreover, reduced melting layer enhancements and delayed radar bright-band signatures in the column are also observed during riming periods, most notably with the profiling radar observations. The bimodal cloud radar Doppler spectra captured near riming zones indicate two time-height spectral ice peaks, one rimed particle peak, and one peak associated with pristine ice needle generation and/or growth between -4°C and -7°C also sampled by aircraft probes. We observe this pristine needle population near the rimed particle region which gives a partial explanation for the enhanced ZDR. The riming signatures aloft and radar measurements within the melting level are weakly lag correlated (r~0.6) with smaller median drop sizes at the surface, as compared with later times when aggregation of larger particle sizes was believed dominant.« less

  6. Folds and Etudes

    ERIC Educational Resources Information Center

    Bean, Robert

    2007-01-01

    In this article, the author talks about "Folds" and "Etudes" which are images derived from anonymous typing exercises that he found in a used copy of "Touch Typing Made Simple". "Etudes" refers to the musical tradition of studies for a solo instrument, which is a typewriter. Typing exercises are repetitive attempts to type words and phrases…

  7. RIME proteomics of estrogen and progesterone receptors in breast cancer

    PubMed Central

    D’Santos, Clive; Taylor, Christopher; Carroll, Jason S.; Mohammed, Hisham

    2015-01-01

    Nuclear receptors play an important role in transcriptional regulation of diverse cellular processes and is also relevant in diseases such as cancer. In breast cancer, the nuclear receptors – estrogen receptor (ER) and progesterone receptor (PR) are classical markers of the disease and are used to classify breast cancer subtypes. Using a recently developed affinity purification MS technique (RIME) [1], we investigate the protein interactors of ER and PR in breast cancer cell lines upon stimulation by the ligands – estrogen and progesterone. The data is deposited at proteomeXchange (PXD002104) and is part of a publication [2] that explains the link between the two nuclear receptors and potential consequences of this in breast cancer. In this manuscript, we describe the methodology used and provide details on experimental procedures, analysis methods and analysis of raw data. The purpose of this article is to enable reproducibility of the data and provide technical recommendations on performing RIME in hormonal contexts. PMID:26543891

  8. Charge transfer during individual collisions in ice growing by riming

    NASA Technical Reports Server (NTRS)

    Avila, Eldo E.; Caranti, Giorgio M.

    1991-01-01

    The charging of a target by riming in the wind was studied in the temperature range of (-10, -18 C). For each temperature, charge transfers of both signs are observed and, according to the environmental conditions, one of them prevails. The charge is more positive as the liquid water concentration is increased at any particular temperature. It is found that even at the low impact velocities used (5 m/s) there is abundant evidence of fragmentation following the collision.

  9. Analysis of Phonemes, Graphemes, Onset-Rimes, and Words with Braille-Learning Children

    ERIC Educational Resources Information Center

    Crawford, Shauna; Elliott, Robert T.

    2007-01-01

    Six primary school-aged braille students were taught to name 4 to 10 braille letters as phonemes and another 4 to 10 braille letters as graphemes (Study 1). They were then taught to name 10 braille words as onset-rimes and another 10 braille words as whole words (Study 2). Instruction in phonemes and onset rimes resulted in fewer trials and a…

  10. Subsyllabic Units in Computerized Reading Instruction: Onset-Rime vs. Postvowel Segmentation.

    ERIC Educational Resources Information Center

    Wise, Barbara W.; And Others

    1990-01-01

    Three experiments with 20 first grade students concerned possible benefits of onset-rime segmentation for reading instruction of children. In all experiments, onset-rime segmentation proved more helpful than postvowel segmentation in short-term learning of single words composed of 4 letters representing 3 and 4 phonemes. (RH)

  11. Getting the "ig" in Pig: Helping Children Discover Onset and Rime.

    ERIC Educational Resources Information Center

    Rosen, Michelle

    This phonics lesson offers a clear instructional format for teaching onset and rime. The "ig" rime is demonstrated through the use of literature, independent and cooperative learning, critical thinking, and hands-on activities. Instruction is conducted in both an explicit and implicit manner. During two to three 40-minute sessions,…

  12. The Role of Phoneme and Onset-Rime Awareness in Second Language Reading Acquisition

    ERIC Educational Resources Information Center

    Haigh, Corinne A.; Savage, Robert; Erdos, Caroline; Genesee, Fred

    2011-01-01

    This study investigated the link between phoneme and onset-rime awareness and reading outcomes in children learning to read in a second language (L2). Closely matched phoneme and onset-rime awareness tasks were administered in English and French in the spring of kindergarten to English-dominant children in French immersion programmes (n=98).…

  13. Investigation of riming within mixed-phase stratiform clouds using Weather Research and Forecasting (WRF) model

    NASA Astrophysics Data System (ADS)

    Hou, Tuanjie; Lei, Hengchi; Yang, Jiefan; Hu, Zhaoxia; Feng, Qiujuan

    2016-09-01

    In this study, we investigated stratiform precipitation associated with an upper-level westerly trough and a cold front over northern China between 30 Apr. and 1 May 2009. We employed the Weather Research and Forecasting (WRF) model (version 3.4.1) to perform high-resolution numerical simulations of rainfall. We also conducted simulations with two microphysics schemes and sensitivity experiments without riming of snow and changing cloud droplet number concentrations (CDNCs) to determine the effect of snow riming on cloud structure and precipitation. Then we compared our results with CloudSat, Doppler radar and rain gauge observations. The comparison with the Doppler radar observations suggested that the WRF model was quite successful in capturing the timing and location of the stratiform precipitation region. Further comparisons with the CloudSat retrievals suggested that both microphysics schemes overestimated ice and liquid water contents. The sensitivity experiments without riming of snow suggested that the presence or absence of riming significantly influenced the precipitation distribution, but only slightly affected total accumulated precipitation. Without riming of snow, the changes of updrafts from the two microphysics schemes were different due to a different consideration of ice particle capacitance and latent heat effect of riming on deposition. While sensitivity experiments with three different CDNC values of 100, 250 and 1000 cm- 3 suggested variations in snow riming rates, changing CDNC had little impact on precipitation.

  14. The biopsychosocial spiritual model applied to the treatment of women with breast cancer, through RIME intervention (relaxation, mental images, spirituality).

    PubMed

    Elias, Ana Catarina Araújo; Ricci, Marcos Desidério; Rodriguez, Lórgio Henrique Diaz; Pinto, Stela Duarte; Giglio, Joel Sales; Baracat, Edmund Chada

    2015-02-01

    This postdoctoral study on the application of the RIME intervention in women that had undergone mastectomy and were in treatment, aimed to promote psychospiritual and social transformations to improve the quality of life, self-esteem and hope. A total of 28 women participated and were randomized into two groups. Brief Psychotherapy (PB) (average of six sessions) was administered in the Control Group, and RIME (three sessions) and BP (average of five sessions) were applied in the RIME Group. The quantitative results indicated a significant improvement (38.3%) in the Perception of Quality of Life after RIME according to the WHOQOL, compared both to the BP of the Control Group (12.5%), and the BP of the RIME Group (16.2%). There was a significant improvement in Self-esteem (Rosenberg) after RIME (14.6%) compared to the BP of the Control Group (worsened 35.9%), and the BP of the RIME Group (8.3%). The improvement in well-being, considering the focus worked on (Visual Analog Scale), was significant in the RIME Group (bad to good), as well as in the Control Group (unpleasant to good). The qualitative results indicated that RIME promotes creative transformations in the intrapsychic and interpersonal dimensions, so that new meanings and/or new attitudes emerge into the consciousness. It was observed that RIME has more strength of psychic structure, ego strengthening and provides a faster transformation that BP, therefore it can be indicated for crisis treatment in the hospital environment.

  15. The Radar for Icy Moon Exploration (RIME) on the JUICE Mission

    NASA Astrophysics Data System (ADS)

    Bruzzone, L.; Plaut, J.; Alberti, G.; Blankenship, D. D.; Bovolo, F.; Campbell, B. A.; Castelletti, D.; Gim, Y.; Ilisei, A. M.; Kofman, W. W.; Komatsu, G.; McKinnon, W. B.; Mitri, G.; Moussessian, A.; Notarnicola, C.; Orosei, R.; Patterson, G. W.; Pettinelli, E.; Plettemeier, D.

    2015-12-01

    The Radar for Icy Moon Exploration (RIME) is one of the main instruments included in the JUpiter ICy moons Explorer (JUICE) ESA mission. It is a radar sounder designed for studying the subsurface geology and geophysics of Galilean icy moons (i.e., Ganymede, Europa and Callisto) and for detecting possible subsurface water. RIME is designed for penetration of the icy moons up to a depth of 9 km. Two main operation scenarios are foreseen for RIME: i) flyby observations of Europa, Ganymede and Callisto (from a distance of 1000 km to the closest approach of about 400 km); and ii) circular orbital observations around Ganymede at 500 km of altitude. According to these scenarios, RIME is designed to explore the icy shell of the Galilean icy satellites by characterizing the wide range of compositional, thermal, and structural variation found in the subsurface of these moons. RIME observations will profile the ice shells of the Galilean icy satellites with specific focus on Ganymede given the circular orbital phase. The acquired measures will provide geological context on hemispheric (thousands of km), regional (hundreds of km with multiple overlaps), and targeted (tens of km) scales appropriate for a variety of hypothesis tests. RIME will operate in a single frequency band, centred at 9 MHz. The frequency was selected as the result of extensive study of penetration capabilities, surface roughness of the moons, Jovian radio noise, antenna accommodation, and system design. The 9 MHz frequency provides penetration capabilities and mitigation of surface scattering (which can cause signal loss and clutter issues), at the expense of mapping coverage, as it is likely to obtain high SNR observations only on the anti-Jovian side of the target moons. The RIME antenna is a 16 m dipole. The chirp pulse bandwidth is up to 3 MHz, which provides vertical resolution of about 50 m in ice after side lobe weighting. RIME will also operate with 1 MHz bandwidth to reduce data volume when

  16. Microscopic observations of riming on an ice surface using high speed video

    NASA Astrophysics Data System (ADS)

    Emersic, C.; Connolly, P. J.

    2017-03-01

    Microscopic droplet riming events on an ice surface have been observed using high speed video. Observations included greater propensity for droplet spreading at temperatures higher than - 15 °C on flatter ice surfaces, and subsequently, the formation of growing rime spires into the flow, allowing glancing droplet collisions and more spherical freezing of smaller droplets. Insight into differences between laboratory observations of the Hallett-Mossop process is offered, relating to the nature of droplet spreading associated with the structure of the rimer surface prior to impact. Observations of a difference between air speed and resulting droplet impact speed on an ice surface may affect interpretations of riming laboratory studies, and may explain recent observations of a high secondary ice production rate in supercooled layer clouds.

  17. Syllable and rime patterns for teaching reading: Analysis of a frequency-based vocabulary of 17,602 words.

    PubMed

    Stanback, M L

    1992-12-01

    A frequency-based vocabulary of 17,602 words was compiled and analyzed in order to group words with recurring syllable and rime patterns for teaching reading. The role of the rime unit (e.g.,ite inkite andinvite) in determining vowel pronunciation was central to the analysis because of the difficulty that the ambiguity of English vowel spelling presents to children who do not learn to read words easily. Vowel pronunciation in each orthographic rime was examined, both for its consistency in all words in which the rime occurs and for regularity, defined as conformity to the most frequent pronunciation for each vowel spelling in each of six orthographic syllable types.Of the 824 different orthographic rimes, 616 occur in rime families as the building blocks of almost all the 43,041 syllables of the words. These rimes account for a striking amount of patterning in the orthography: 436 are both regular and consistent in pronunciation (except where a single exception word occurs); another 55 are consistent but not regular. Of the remaining 125, only 86 have less than a 90 percent level of consistency. The high order of congruence of orthographic and phonological rimes suggests their usefulness as units for teaching reading.

  18. Rime and graupel: Description and characterization as revealed by low-temperature scanning electron microscopy

    USGS Publications Warehouse

    Rango, A.; Foster, J.; Josberger, E.G.; Erbe, E.F.; Pooley, C.; Wergin, W.P.

    2003-01-01

    Snow crystals, which form by vapor deposition, occasionally come in contact with supercooled cloud droplets during their formation and descent. When this occurs, the droplets adhere and freeze to the snow crystals in a process known as accretion. During the early stages of accretion, discrete snow crystals exhibiting frozen cloud droplets are referred to as rime. If this process continues, the snow crystal may become completely engulfed in frozen cloud droplets. The resulting particle is known as graupel. Light microscopic investigations have studied rime and graupel for nearly 100 years. However, the limiting resolution and depth of field associated with the light microscope have prevented detailed descriptions of the microscopic cloud droplets and the three-dimensional topography of the rime and graupel particles. This study uses low-temperature scanning electron microscopy to characterize the frozen precipitates that are commonly known as rime and graupel. Rime, consisting of frozen cloud droplets, is observed on all types of snow crystals including needles, columns, plates, and dendrites. The droplets, which vary in size from 10 to 100 μm, frequently accumulate along one face of a single snow crystal, but are found more randomly distributed on aggregations consisting of two or more snow crystals (snowflakes). The early stages of riming are characterized by the presence of frozen cloud droplets that appear as a layer of flattened hemispheres on the surface of the snow crystal. As this process continues, the cloud droplets appear more sinuous and elongate as they contact and freeze to the rimed crystals. The advanced stages of this process result in graupel, a particle 1 to 3 mm across, composed of hundreds of frozen cloud droplets interspersed with considerable air spaces; the original snow crystal is no longer discernible. This study increases our knowledge about the process and characteristics of riming and suggests that the initial appearance of the

  19. Rime and graupel: description and characterization as revealed by low-temperature scanning electron microscopy.

    PubMed

    Rango, Albert; Foster, James; Josberger, Edward G; Erbe, Eric F; Pooley, Christopher; Wergin, William P

    2003-01-01

    Snow crystals, which form by vapor deposition, occasionally come in contact with supercooled cloud droplets during their formation and descent. When this occurs, the droplets adhere and freeze to the snow crystals in a process known as accretion. During the early stages of accretion, discrete snow crystals exhibiting frozen cloud droplets are referred to as rime. If this process continues, the snow crystal may become completely engulfed in frozen cloud droplets. The resulting particle is known as graupel. Light microscopic investigations have studied rime and graupel for nearly 100 years. However, the limiting resolution and depth of field associated with the light microscope have prevented detailed descriptions of the microscopic cloud droplets and the three-dimensional topography of the rime and graupel particles. This study uses low-temperature scanning electron microscopy to characterize the frozen precipitates that are commonly known as rime and graupel. Rime, consisting of frozen cloud droplets, is observed on all types of snow crystals including needles, columns, plates, and dendrites. The droplets, which vary in size from 10 to 100 microm, frequently accumulate along one face of a single snow crystal, but are found more randomly distributed on aggregations consisting of two or more snow crystals (snowflakes). The early stages of riming are characterized by the presence of frozen cloud droplets that appear as a layer of flattened hemispheres on the surface of the snow crystal. As this process continues, the cloud droplets appear more sinuous and elongate as they contact and freeze to the rimed crystals. The advanced stages of this process result in graupel, a particle 1 to 3 mm across, composed of hundreds of frozen cloud droplets interspersed with considerable air spaces; the original snow crystal is no longer discernible. This study increases our knowledge about the process and characteristics of riming and suggests that the initial appearance of the

  20. Reimagining Coleridge's "Rime of the Ancient Mariner" through Visual and Performing Arts Projects

    ERIC Educational Resources Information Center

    Michaels, Judy Rowe

    2009-01-01

    In this article, the author discusses how students create their arts projects by responding to Samuel Taylor Coleridge's "Rime of the Ancient Mariner." In creating their arts projects, students incorporate film, painting, performance, and other arts in their imaginative and innovative responses to Coleridge's classic work. The author discusses…

  1. Rime ice accretion and its effect on airfoil performance. Ph.D. Thesis. Final Report

    NASA Technical Reports Server (NTRS)

    Bragg, M. B.

    1982-01-01

    A methodology was developed to predict the growth of rime ice, and the resulting aerodynamic penalty on unprotected, subcritical, airfoil surfaces. The system of equations governing the trajectory of a water droplet in the airfoil flowfield is developed and a numerical solution is obtained to predict the mass flux of super cooled water droplets freezing on impact. A rime ice shape is predicted. The effect of time on the ice growth is modeled by a time-stepping procedure where the flowfield and droplet mass flux are updated periodically through the ice accretion process. Two similarity parameters, the trajectory similarity parameter and accumulation parameter, are found to govern the accretion of rime ice. In addition, an analytical solution is presented for Langmuir's classical modified inertia parameter. The aerodynamic evaluation of the effect of the ice accretion on airfoil performance is determined using an existing airfoil analysis code with empirical corrections. The change in maximum lift coefficient is found from an analysis of the new iced airfoil shape. The drag correction needed due to the severe surface roughness is formulated from existing iced airfoil and rough airfoil data. A small scale wind tunnel test was conducted to determine the change in airfoil performance due to a simulated rime ice shape.

  2. Syllable Splitting in Literate and Preliterate Hebrew Speakers: Onsets and Rimes or Bodies and Codas?

    ERIC Educational Resources Information Center

    Share, David L.; Blum, Peri

    2005-01-01

    This study examined consonant-vowel-consonant (CVC) syllable splitting among literate (Grade 2) and preliterate (kindergarten) Hebrew speakers. Consideration of both the architecture of Hebrew orthography and phonology led to the prediction that a body-coda rather than an onset-rime subdivision would predominate. Structured and unstructured tasks…

  3. Sensitivity to Rime Unit Frequency and Children's Early Word-Reading Strategies

    ERIC Educational Resources Information Center

    Coyne, Emily; Farrington-Flint, Lee; Underwood, Jean; Stiller, James

    2012-01-01

    The current work examines children's sensitivity to rime unit spelling-sound correspondences within the context of early word reading as a way of assessing word-specific influences on early word-reading strategies. Sixty 6-7-year-olds participated in an experimental reading task that comprised word items that shared either frequent or infrequent…

  4. Phoneme Manipulation Not Onset-Rime Manipulation Ability Is a Unique Predictor of Early Reading

    ERIC Educational Resources Information Center

    Savage, Robert; Carless, Sue

    2005-01-01

    Background: Phonological awareness is known to be an excellent predictor of later reading acquisition. It remains unclear, however, whether phoneme manipulation alone best explains this association or whether an additional direct contribution of onset-rime awareness is predictive. This issue is explored here. Method: A longitudinal study is…

  5. Assessing the potential for passive radio sounding of Europa and Ganymede with RIME and REASON

    NASA Astrophysics Data System (ADS)

    Schroeder, Dustin M.; Romero-Wolf, Andrew; Carrer, Leonardo; Grima, Cyril; Campbell, Bruce A.; Kofman, Wlodek; Bruzzone, Lorenzo; Blankenship, Donald D.

    2016-12-01

    Recent work has raised the potential for Jupiter's decametric radiation to be used as a source for passive radio sounding of its icy moons. Two radar sounding instruments, the Radar for Icy Moon Exploration (RIME) and the Radar for Europa Assessment and Sounding: Ocean to Near-surface (REASON) have been selected for ESA and NASA missions to Ganymede and Europa. Here, we revisit the projected performance of the passive sounding concept and assess the potential for its implementation as an additional mode for RIME and REASON. We find that the Signal to Noise Ratio (SNR) of passive sounding can approach or exceed that of active sounding in a noisy sub-Jovian environment, but that active sounding achieves a greater SNR in the presence of quiescent noise and outperforms passive sounding in terms of clutter. We also compare the performance of passive sounding at the 9 MHz HF center frequency of RIME and REASON to other frequencies within the Jovian decametric band. We conclude that the addition of a passive sounding mode on RIME or REASON stands to enhance their science return by enabling sub-Jovian HF sounding in the presence of decametric noise, but that there is not a compelling case for implementation at a different frequency.

  6. Understanding the Role of Riming in Deep Convection Through Variability in Collection Efficiencies and Aerosol Effects

    NASA Astrophysics Data System (ADS)

    Saleeby, S. M.; van den Heever, S. C.; Marinescu, P. J.; Kreidenweis, S. M.; DeMott, P. J.; Tao, W. K.; Matsui, T.; Wu, D.

    2015-12-01

    In many mixed-phase cloud systems, the riming of cloud droplets is a key microphysical process in the growth of precipitation-sized hydrometeors. The relative importance of riming compared to other hydrometeor growth mechanisms depends on the type of cloud system and the mass, size, and number concentration of cloud droplets and ice species. In a perturbed climate state, the nature of deep convection may be altered through changes in the environmental conditions and aerosol concentrations. Such climate-induced variability can modify the dominant microphysical processes that generate precipitation through changes in hydrometeor size spectra. Such changes could either increase or decrease precipitation production and efficiency as well as impact associated morphology of clouds and convection. If the efficiency of the riming process is modified through these climate changes, it can alter the accumulated precipitation, precipitation intensity, spatial and temporal distribution of cloud and ice water, and the radiation budget through the modification of ice spectra and areal coverage of upper-level anvil clouds. The impacts of variability in aerosol concentration and collision efficiencies on the riming process in deep convection is explored through the use of high-resolution cloud resolving model simulations of a squall line that occurred May 20, 2011 over the U.S. central plains during the MC3E field project. Results thus far have demonstrated that changes in the riming rates strongly impact the intensity and partitioning of squall line precipitation between convective and stratiform, the lofting of condensate to upper levels, the vertical distribution of latent heating, and the area and optical thickness of stratiform anvil clouds. Analyses from direct tests of microphysical processes have revealed that a reduction in riming rates leads to less precipitation, greater amounts of lofted cloud water, and greater ice mass in cirrus anvils. Further, an increase in aerosol

  7. Onsets and rimes in a phonologically transparent orthography: differences between good and poor beginning readers of Dutch.

    PubMed

    Geudens, A; Sandra, D

    This study investigates whether beginning readers of Dutch develop onset-rime units when these units are emphasized in their reading method, even when the orthography is transparent at the grapheme-phoneme level. The speed of naming intact pseudowords (wot) was compared with the speed of naming pseudowords with an onset-rime (w ot) or body-coda (wo t) segmentation. Whereas body-coda items consistently slowed down naming for both good and poor readers, the onset-rime effect covaried with reading skill: it changed from inhibitory for good readers to facilitatory for poor readers. Two alternative explanations are proposed.

  8. Wind tunnel investigations on the retention of carboxylic acids during riming

    NASA Astrophysics Data System (ADS)

    Jost, Alexander; Szakáll, Miklós; Diehl, Karoline; Mitra, Subir K.; Borrmann, Stephan

    2015-04-01

    In mid-latitudes, precipitation is mainly initiated via the ice phase in mixed phase clouds. In such clouds the ice particles grow to precipitation sizes at the expense of liquid drops through riming which means that supercooled droplets collide with ice particles and subsequently freeze. Water-soluble trace substances present in the liquid phase might remain only fractionally in the ice phase after freezing. This fractionation is called retention and is an important ratio which quantifies the partitioning of atmospheric trace substances between the phases. Laboratory experiments were carried out at the Mainz vertical wind tunnel to determine the retention of lower mono- and di-carboxylic acids during riming. Due to their low molecular weight and their polarity these acids are water-soluble. In the atmosphere formic acid and acetic acid are the most abundant mono-carboxylic acids in the gas and aqueous phase, thus, they represent the major fraction of carboxylic acids in cloud water. Oxalic and malonic acid are common coatings on aerosol particles because of their relatively low saturation vapor pressure. These di-carboxylic acids might therefore promote the aerosol particles to act as cloud condensation nuclei and additionally contribute to the aqueous phase chemistry in cloud droplets. The conditions during the riming experiments in the wind tunnel were similar to those in atmospheric mixed phase clouds, i.e. temperatures from -18°C to -6 °C, liquid water contents between 0.5 and 1.5 g/m3, and liquid drop radii between 10 and 20 μm. The liquid phase concentrations ranged from 3 to 5 mg/l (4.1 < pH < 4.5). As rime collectors captively floating ice particles and quasi-floating snowflakes with diameters between 0.6 and 1.5 cm were used. The wind speed in the vertical wind tunnel was very close to the terminal velocities of the rime collectors, thus, the ventilation during riming was in the same order of magnitude as under atmospheric riming conditions. After

  9. Water Droplet Impingement on Simulated Glaze, Mixed, and Rime Ice Accretions

    NASA Technical Reports Server (NTRS)

    Papadakis, Michael; Rachman, Arief; Wong, See-Cheuk; Yeong, Hsiung-Wei; Hung, Kuohsing E.; Vu, Giao T.; Bidwell, Colin S.

    2007-01-01

    Water droplet impingement data were obtained at the NASA Glenn Icing Research Tunnel (IRT) for a 36-in. chord NACA 23012 airfoil with and without simulated ice using a dye-tracer method. The simulated ice shapes were defined with the NASA Glenn LEWICE 2.2 ice accretion program and including one rime, four mixed and five glaze ice shapes. The impingement experiments were performed with spray clouds having median volumetric diameters of 20, 52, 111, 154, and 236 micron. Comparisons to the experimental data were generated which showed good agreement for the rime and mixed shapes at lower drop sizes. For larger drops sizes LEWICE 2.2 over predicted the collection efficiencies due to droplet splashing effects which were not modeled in the program. Also for the more complex glaze ice shapes interpolation errors resulted in the over prediction of collection efficiencies in cove or shadow regions of ice shapes.

  10. Rime-, mixed- and glaze-ice evaluations of three scaling laws

    NASA Technical Reports Server (NTRS)

    Anderson, David N.

    1994-01-01

    This report presents the results of tests at NASA Lewis to evaluate three icing scaling relationships or 'laws' for an unheated model. The laws were LWC x time = constant, one proposed by a Swedish-Russian group and one used at ONERA in France. Icing tests were performed in the NASA Lewis Icing Research Tunnel (IRT) with cylinders ranging from 2.5- to 15.2-cm diameter. Reference conditions were chosen to provide rime, mixed and glaze ice. Scaled conditions were tested for several scenarios of size and velocity scaling, and the resulting ice shapes compared. For rime-ice conditions, all three of the scaling laws provided scaled ice shapes which closely matched reference ice shapes. For mixed ice and for glaze ice none of the scaling laws produced consistently good simulation of the reference ice shapes. Explanations for the observed results are proposed, and scaling issues requiring further study are identified.

  11. Using Field and Satellite Measurements to Improve Snow and Riming Processes in Cloud Resolving Models

    NASA Technical Reports Server (NTRS)

    Colle, Brian A.; Molthan, Andrew L.

    2013-01-01

    The representation of clouds in climate and weather models is a driver in forecast uncertainty. Cloud microphysics parameterizations are challenged by having to represent a diverse range of ice species. Key characteristics of predicted ice species include habit and fall speed, and complex interactions that result from mixed-phased processes like riming. Our proposed activity leverages Global Precipitation Measurement (GPM) Mission ground validation studies to improve parameterizations

  12. Fingerprints of a riming event on cloud radar Doppler spectra: observations and modeling

    NASA Astrophysics Data System (ADS)

    Kalesse, H.; Szyrmer, W.; Kneifel, S.; Kollias, P.; Luke, E.

    2015-10-01

    Radar Doppler spectra measurements are exploited to study a riming event when precipitating ice from a seeder cloud sediments through a supercooled liquid water (SLW) layer. The observations were collected during the deployment of the Atmospheric Radiation Measurement Program's (ARM) mobile facility AMF2 at Hyytiälä, Finland during the BAECC (Biogenic Aerosols - Effects on Clouds and Climate Snowfall Experiment) field campaign. The presented analysis of the height evolution of the radar Doppler spectra is a state-of-the-art retrieval with profiling cloud radars in SLW layers beyond the traditional use of spectral moments. Dynamical effects are taken into account by following the particle population evolution along slanted tracks that are caused by horizontal advection of the cloud under wind shear conditions. In the SLW layer, the identified liquid peak is used as an air motion tracer to correct the Doppler spectra for vertical air motion and the ice peak is used to study the radar profiles of rimed particles. A 1-D steady-state bin microphysical model is constrained using the SLW and air motion profiles and cloud top radar observations. The observed radar moment profiles of the rimed snow can be simulated reasonably well by the model, but not without making several assumptions about the ice particle concentration and the relative role of deposition and aggregation. This suggests that in-situ observations of key ice properties are needed to complement the profiling radar observations before process-oriented studies can effectively evaluate ice microphysical parameterizations.

  13. Fingerprints of a riming event on cloud radar Doppler spectra: observations and modeling

    SciTech Connect

    Kalesse, Heike; Szyrmer, Wanda; Kneifel, Stefan; Kollias, Pavlos; Luke, Edward

    2016-03-09

    In this paper, Radar Doppler spectra measurements are exploited to study a riming event when precipitating ice from a seeder cloud sediment through a supercooled liquid water (SLW) layer. The focus is on the "golden sample" case study for this type of analysis based on observations collected during the deployment of the Atmospheric Radiation Measurement Program's (ARM) mobile facility AMF2 at Hyytiälä, Finland, during the Biogenic Aerosols – Effects on Clouds and Climate (BAECC) field campaign. The presented analysis of the height evolution of the radar Doppler spectra is a state-of-the-art retrieval with profiling cloud radars in SLW layers beyond the traditional use of spectral moments. Dynamical effects are considered by following the particle population evolution along slanted tracks that are caused by horizontal advection of the cloud under wind shear conditions. In the SLW layer, the identified liquid peak is used as an air motion tracer to correct the Doppler spectra for vertical air motion and the ice peak is used to study the radar profiles of rimed particles. A 1-D steady-state bin microphysical model is constrained using the SLW and air motion profiles and cloud top radar observations. The observed radar moment profiles of the rimed snow can be simulated reasonably well by the model, but not without making several assumptions about the ice particle concentration and the relative role of deposition and aggregation. In conclusion, this suggests that in situ observations of key ice properties are needed to complement the profiling radar observations before process-oriented studies can effectively evaluate ice microphysical parameterizations.

  14. Fingerprints of a riming event on cloud radar Doppler spectra: observations and modeling

    NASA Astrophysics Data System (ADS)

    Kalesse, Heike; Szyrmer, Wanda; Kneifel, Stefan; Kollias, Pavlos; Luke, Edward

    2016-03-01

    Radar Doppler spectra measurements are exploited to study a riming event when precipitating ice from a seeder cloud sediment through a supercooled liquid water (SLW) layer. The focus is on the "golden sample" case study for this type of analysis based on observations collected during the deployment of the Atmospheric Radiation Measurement Program's (ARM) mobile facility AMF2 at Hyytiälä, Finland, during the Biogenic Aerosols - Effects on Clouds and Climate (BAECC) field campaign. The presented analysis of the height evolution of the radar Doppler spectra is a state-of-the-art retrieval with profiling cloud radars in SLW layers beyond the traditional use of spectral moments. Dynamical effects are considered by following the particle population evolution along slanted tracks that are caused by horizontal advection of the cloud under wind shear conditions. In the SLW layer, the identified liquid peak is used as an air motion tracer to correct the Doppler spectra for vertical air motion and the ice peak is used to study the radar profiles of rimed particles. A 1-D steady-state bin microphysical model is constrained using the SLW and air motion profiles and cloud top radar observations. The observed radar moment profiles of the rimed snow can be simulated reasonably well by the model, but not without making several assumptions about the ice particle concentration and the relative role of deposition and aggregation. This suggests that in situ observations of key ice properties are needed to complement the profiling radar observations before process-oriented studies can effectively evaluate ice microphysical parameterizations.

  15. Fingerprints of a riming event on cloud radar Doppler spectra: observations and modeling

    DOE PAGES

    Kalesse, Heike; Szyrmer, Wanda; Kneifel, Stefan; ...

    2016-03-09

    In this paper, Radar Doppler spectra measurements are exploited to study a riming event when precipitating ice from a seeder cloud sediment through a supercooled liquid water (SLW) layer. The focus is on the "golden sample" case study for this type of analysis based on observations collected during the deployment of the Atmospheric Radiation Measurement Program's (ARM) mobile facility AMF2 at Hyytiälä, Finland, during the Biogenic Aerosols – Effects on Clouds and Climate (BAECC) field campaign. The presented analysis of the height evolution of the radar Doppler spectra is a state-of-the-art retrieval with profiling cloud radars in SLW layers beyondmore » the traditional use of spectral moments. Dynamical effects are considered by following the particle population evolution along slanted tracks that are caused by horizontal advection of the cloud under wind shear conditions. In the SLW layer, the identified liquid peak is used as an air motion tracer to correct the Doppler spectra for vertical air motion and the ice peak is used to study the radar profiles of rimed particles. A 1-D steady-state bin microphysical model is constrained using the SLW and air motion profiles and cloud top radar observations. The observed radar moment profiles of the rimed snow can be simulated reasonably well by the model, but not without making several assumptions about the ice particle concentration and the relative role of deposition and aggregation. In conclusion, this suggests that in situ observations of key ice properties are needed to complement the profiling radar observations before process-oriented studies can effectively evaluate ice microphysical parameterizations.« less

  16. Assessing the Effectiveness of Two Theoretically Motivated Computer-Assisted Reading Interventions in the United Kingdom: GG Rime and GG Phoneme

    ERIC Educational Resources Information Center

    Kyle, Fiona; Kujala, Janne; Richardson, Ulla; Lyytinen, Heikki; Goswami, Usha

    2013-01-01

    We report an empirical comparison of the effectiveness of two theoretically motivated computer-assisted reading interventions (CARI) based on the Finnish GraphoGame CARI: English GraphoGame Rime (GG Rime) and English GraphoGame Phoneme (GG Phoneme). Participants were 6-7-year-old students who had been identified by their teachers as being…

  17. Rhyming Words and Onset-Rime Constituents: An Inquiry into Structural Breaking Points and Emergent Boundaries in the Syllable

    ERIC Educational Resources Information Center

    Geudens, Astrid; Sandra, Dominiek; Martensen, Heike

    2005-01-01

    Geudens and Sandra, in their 2003 study, investigated the special role of onsets and rimes in Dutch-speaking children's explicit phonological awareness. In the current study, we tapped implicit phonological knowledge using forced-choice similarity judgment (Experiment 1) and recall of syllable lists (Experiment 2). In Experiment 1, Dutch-speaking…

  18. Orthographic Consistency and Word-Frequency Effects in Auditory Word Recognition: New Evidence from Lexical Decision and Rime Detection

    PubMed Central

    Petrova, Ana; Gaskell, M. Gareth; Ferrand, Ludovic

    2011-01-01

    Many studies have repeatedly shown an orthographic consistency effect in the auditory lexical decision task. Words with phonological rimes that could be spelled in multiple ways (i.e., inconsistent words) typically produce longer auditory lexical decision latencies and more errors than do words with rimes that could be spelled in only one way (i.e., consistent words). These results have been extended to different languages and tasks, suggesting that the effect is quite general and robust. Despite this growing body of evidence, some psycholinguists believe that orthographic effects on spoken language are exclusively strategic, post-lexical, or restricted to peculiar (low-frequency) words. In the present study, we manipulated consistency and word-frequency orthogonally in order to explore whether the orthographic consistency effect extends to high-frequency words. Two different tasks were used: lexical decision and rime detection. Both tasks produced reliable consistency effects for both low- and high-frequency words. Furthermore, in Experiment 1 (lexical decision), an interaction revealed a stronger consistency effect for low-frequency words than for high-frequency words, as initially predicted by Ziegler and Ferrand (1998), whereas no interaction was found in Experiment 2 (rime detection). Our results extend previous findings by showing that the orthographic consistency effect is obtained not only for low-frequency words but also for high-frequency words. Furthermore, these effects were also obtained in a rime detection task, which does not require the explicit processing of orthographic structure. Globally, our results suggest that literacy changes the way people process spoken words, even for frequent words. PMID:22025916

  19. Rapid immunoprecipitation mass spectrometry of endogenous proteins (RIME) for analysis of chromatin complexes.

    PubMed

    Mohammed, Hisham; Taylor, Christopher; Brown, Gordon D; Papachristou, Evaggelia K; Carroll, Jason S; D'Santos, Clive S

    2016-02-01

    Rapid immunoprecipitation mass spectrometry of endogenous protein (RIME) is a method that allows the study of protein complexes, in particular chromatin and transcription factor complexes, in a rapid and robust manner by mass spectrometry (MS). The method can be used in parallel with chromatin immunoprecipitation-sequencing (ChIP-seq) experiments to provide information on both the cistrome and interactome for a given protein. The method uses formaldehyde fixation to stabilize protein complexes. By using antibodies against the endogenous target, the cross-linked complex is immunoprecipitated, rigorously washed, and then digested into peptides while avoiding antibody contamination (on-bead digestion). By using this method, MS identification of the target protein and several dozen interacting proteins is possible using a 100-min LC-MS/MS run. The protocol does not require substantial proteomics expertise, and it typically takes 2-3 d from the collection of material to results.

  20. Super flame-retardant lightweight rime-like carbon-phenolic nanofoam

    NASA Astrophysics Data System (ADS)

    Cheng, Haiming; Hong, Changqing; Zhang, Xinghong; Xue, Huafei; Meng, Songhe; Han, Jiecai

    2016-09-01

    The desire for lightweight nanoporous materials with high-performance thermal insulation and efficient anti-ablation resistance for energy conservation and thermal protection/insulation has greatly motivated research and development recently. The main challenge to synthesize such lightweight materials is how to balance the relationship of low thermal conductivity and flame retardancy. Herein, we propose a new concept of lightweight “rime-like” structured carbon-phenolic nanocomposites to solve this problem, where the 3D chopped network-structured carbon fiber (NCF) monoliths are incorporated with nanoporous phenolic aerogel to retain structural and functional integrity. The nanometer-scaled porous phenolic (NP) was synthesized through polymerization-induced phase separation and ambient pressure drying using phenolic resin (PR) solution as reaction source, ethylene glycol (EG) as solvent and hexamethylenetetramine (HMTA) as catalyst. We demonstrate that the as-prepared NCF-NP nanocomposite exhibits with a low density of 0.25–0.35 g/cm3, low thermal conductivity of 0.125 Wm‑1K‑1 and outstanding flame retardancy exceeding 2000 °C under arc-jet wind tunnel simulation environment. Our results show that the synthesis strategy is a promising approach for producing nanocomposites with excellent high-temperature heat blocking property.

  1. Super flame-retardant lightweight rime-like carbon-phenolic nanofoam

    PubMed Central

    Cheng, Haiming; Hong, Changqing; Zhang, Xinghong; Xue, Huafei; Meng, Songhe; Han, Jiecai

    2016-01-01

    The desire for lightweight nanoporous materials with high-performance thermal insulation and efficient anti-ablation resistance for energy conservation and thermal protection/insulation has greatly motivated research and development recently. The main challenge to synthesize such lightweight materials is how to balance the relationship of low thermal conductivity and flame retardancy. Herein, we propose a new concept of lightweight “rime-like” structured carbon-phenolic nanocomposites to solve this problem, where the 3D chopped network-structured carbon fiber (NCF) monoliths are incorporated with nanoporous phenolic aerogel to retain structural and functional integrity. The nanometer-scaled porous phenolic (NP) was synthesized through polymerization-induced phase separation and ambient pressure drying using phenolic resin (PR) solution as reaction source, ethylene glycol (EG) as solvent and hexamethylenetetramine (HMTA) as catalyst. We demonstrate that the as-prepared NCF-NP nanocomposite exhibits with a low density of 0.25–0.35 g/cm3, low thermal conductivity of 0.125 Wm−1K−1 and outstanding flame retardancy exceeding 2000 °C under arc-jet wind tunnel simulation environment. Our results show that the synthesis strategy is a promising approach for producing nanocomposites with excellent high-temperature heat blocking property. PMID:27629114

  2. ETUDE - European Trade Union Distance Education.

    ERIC Educational Resources Information Center

    Creanor, Linda; Walker, Steve

    2000-01-01

    Describes transnational distance learning activities among European trade union educators carried out as part of the European Trade Union Distance Education (ETUDE) project, supported by the European Commission. Highlights include the context of international trade union distance education; tutor training course; tutors' experiences; and…

  3. Centre National d'Etudes Spatiales

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    The Centre National d'Etudes Spatiales (CNES) draws up, proposes and conducts France's space policy. Its role is to develop the uses of space, to meet the civilian and military needs of public bodies and of the scientific community, and to foster the development and dissemination of new applications, designed to create wealth and jobs....

  4. Apport du rayonnement synchrotron à l'étude de cheveux archéologiques

    NASA Astrophysics Data System (ADS)

    Bertrand, L.; Chevallier, P.; Doucet, J.; Simionovici, A.; Tsoucaris, G.; Walter, P.

    2002-07-01

    La préservation dans certains contextes archéologiques des cheveux humains et des fibres animales est favorisée par leur transformation chimique au contact d'objets métalliques. Afin de mieux comprendre les phénomènes complexes mis en jeu, nous avons étudié expérimentalement la fixation de cations métalliques (Cu et Pb) dans des cheveux modèles à partir de différentes méthodes de caractérisation utilisant le rayonnement X synchrotron. Nous avons ainsi pu mettre en évidence la fixation spécifique d'une partie de ces cations au sein des lipides structurés du cheveu. La comparaison entre échantillons modèles et archéologiques apporte de nouvelles données concernant les premières étapes d'altération des cheveux archéologiques.

  5. Action Research of a Color-Coded, Onset-Rime Decoding Intervention: Examining the Effects with First Grade Students Identified as at Risk

    ERIC Educational Resources Information Center

    Wall, Candace A.; Rafferty, Lisa A.; Camizzi, Mariya A.; Max, Caroline A.; Van Blargan, David M.

    2016-01-01

    Many students who struggle to obtain the alphabetic principle are at risk for being identified as having a reading disability and would benefit from additional explicit phonics instruction as a remedial measure. In this action research case study, the research team conducted two experiments to investigate the effects of a color-coded, onset-rime,…

  6. Application des codes de Monte Carlo à la radiothérapie par rayonnement à faible TEL

    NASA Astrophysics Data System (ADS)

    Marcié, S.

    1998-04-01

    In radiation therapy, there is low LET rays: photons of 60Co, photons and electrons to 4 at 25 MV created in a linac, photons 137Cs, of 192Ir and of 125I. To know the most exactly possible the dose to the tissu by this rays, software and measurements are used. With the development of the power and the capacity of computers, the application of Monte Carlo codes expand to the radiation therapy which have permitted to better determine effects of rays and spectra, to explicit parameters used in dosimetric calculation, to verify algorithms , to study measuremtents systems and phantoms, to calculate the dose in inaccessible points and to consider the utilization of new radionuclides. En Radiothérapie, il existe une variété, de rayonnements ? faible TLE : photons du cobalt 60, photons et ,électron de 4 à? 25 MV générés dans des accélérateurs linéaires, photons du césium 137, de l'iridium 192 et de l'iode 125. Pour connatre le plus exactement possible la dose délivrée aux tissus par ces rayonnements, des logiciels sont utilisés ainsi que des instruments de mesures. Avec le développement de la puissance et de la capacité, des calculateurs, l'application des codes de Monte Carlo s'est ,étendue ? la Radiothérapie ce qui a permis de mieux cerner les effets des rayonnements, déterminer les spectres, préciser les valeurs des paramètres utilisés dans les calculs dosimétriques, vérifier les algorithmes, ,étudier les systèmes de mesures et les fantomes utilisés, calculer la dose en des points inaccessibles ?à la mesure et envisager l'utilisation de nouveaux radio,éléments.

  7. Numerical Analysis Using WRF-SBM for the Cloud Microphysical Structures in the C3VP Field Campaign: Impacts of Supercooled Droplets and Resultant Riming on Snow Microphysics

    NASA Technical Reports Server (NTRS)

    Iguchi, Takamichi; Matsui, Toshihisa; Shi, Jainn J.; Tao, Wei-Kuo; Khain, Alexander P.; Hao, Arthur; Cifelli, Robert; Heymsfield, Andrew; Tokay, Ali

    2012-01-01

    Two distinct snowfall events are observed over the region near the Great Lakes during 19-23 January 2007 under the intensive measurement campaign of the Canadian CloudSat/CALIPSO validation project (C3VP). These events are numerically investigated using the Weather Research and Forecasting model coupled with a spectral bin microphysics (WRF-SBM) scheme that allows a smooth calculation of riming process by predicting the rimed mass fraction on snow aggregates. The fundamental structures of the observed two snowfall systems are distinctly characterized by a localized intense lake-effect snowstorm in one case and a widely distributed moderate snowfall by the synoptic-scale system in another case. Furthermore, the observed microphysical structures are distinguished by differences in bulk density of solid-phase particles, which are probably linked to the presence or absence of supercooled droplets. The WRF-SBM coupled with Goddard Satellite Data Simulator Unit (G-SDSU) has successfully simulated these distinctive structures in the three-dimensional weather prediction run with a horizontal resolution of 1 km. In particular, riming on snow aggregates by supercooled droplets is considered to be of importance in reproducing the specialized microphysical structures in the case studies. Additional sensitivity tests for the lake-effect snowstorm case are conducted utilizing different planetary boundary layer (PBL) models or the same SBM but without the riming process. The PBL process has a large impact on determining the cloud microphysical structure of the lake-effect snowstorm as well as the surface precipitation pattern, whereas the riming process has little influence on the surface precipitation because of the small height of the system.

  8. Lead fluxes and 206Pb/207Pb isotope ratios in rime and snow collected at remote mountain-top locations (Czech Republic, Central Europe): Patterns and sources

    NASA Astrophysics Data System (ADS)

    Cimova, Nikoleta; Novak, Martin; Chrastny, Vladislav; Curik, Jan; Veselovsky, Frantisek; Blaha, Vladimir; Prechova, Eva; Pasava, Jan; Houskova, Marie; Bohdalkova, Leona; Stepanova, Marketa; Mikova, Jitka; Krachler, Michael; Komarek, Arnost

    2016-10-01

    During three winter seasons (2009-2011), Pb concentrations were measured in precipitation at 10 high-elevation sites in the Czech Republic, close to the borders with Austria, Germany, Poland, and Slovakia. Soluble and insoluble Pb forms were quantified in snow (vertical deposition), and rime (horizontal deposition). The objective was to compare Pb input fluxes into ecosystems via vertical and horizontal deposition, and to identify the residual Pb pollution sources in an era of rapidly decreasing industrial pollution. Lead soluble in diluted HNO3 made up 96% of total Pb deposition, with the remaining 4% Pb bound mainly in silicates. Three times higher concentrations of soluble Pb in rime than in snow, and 2.5 times higher concentrations of insoluble Pb in rime than in snow were associated with slightly different Pb isotope ratios. On average, the 206Pb/207Pb ratios in rime were higher than those in snow. Higher mean 206Pb/207Pb ratios of insoluble Pb (1.175) than in soluble Pb (1.165) may indicate an increasing role of geogenic Pb in recent atmospheric deposition. A distinct reversal to more radiogenic 206Pb/207Pb ratios in snow and rime in 2010, compared to literature data from rain-fed Sphagnum peatlands (1800-2000 A.D.), documented a recent decrease in anthropogenic Pb in the atmosphere of Central Europe. Since the early 1980s, Pb concentrations in snow decreased 18 times in the rural south of the Czech Republic, but only twice in the industrial north of the Czech Republic. Isotope signatures indicated that Pb in today's atmospheric deposition is mainly derived from Mesozoic ores mined/processed in Poland and coal combustion in the Czech Republic and Poland.

  9. CAPELLA : une source de rayonnement extrême UV à 13.5 nm par décharge capillaire

    NASA Astrophysics Data System (ADS)

    Sarroukh, O.; Robert, E.; Gonthiez, T.; Thomann, A. L.; Viladrosa, R.; Fleurier, C.; Pouvesle, J. M.; Cachoncinlle, C.

    2003-06-01

    Au GREMI, nous étudions le fonctionnement d'une lampe de rayonnement Extrême Ultraviolet (EUV) émettant à 13.5nm: CAPELLA. Cette lampe consiste en une décharge capillaire dans un flux de xénon continu à basse pression. L'utilisation de Xénon à basse pression dans cette décharge permet la production de photons de faible longueur d'onde dans l'EUV. Dans cet article, nous présentons l'étude et la caractérisation de cette lampe ainsi que ses principales performances, en particulier les résultats des analyses des débris émis par la lampe pendant quelques millions de tirs.

  10. Atmospheric deposition of beryllium in Central Europe: comparison of soluble and insoluble fractions in rime and snow across a pollution gradient.

    PubMed

    Bohdalkova, Leona; Novak, Martin; Voldrichova, Petra; Prechova, Eva; Veselovsky, Frantisek; Erbanova, Lucie; Krachler, Michael; Komarek, Arnost; Mikova, Jitka

    2012-11-15

    Little is known about atmospheric input of beryllium (Be) into ecosystems, despite its highly toxic behavior. For three consecutive winters (2009-2011), we measured Be concentrations in horizontal deposition (rime) and vertical deposition (snow) at 10 remote mountain-top locations in the Czech Republic, Central Europe. Beryllium was determined both in filtered waters, and in HF digests of insoluble particles. Across the sites, soluble Be concentrations in rime were 7 times higher, compared to snow (6.1 vs. 0.9ng·L(-1)). Rime scavenged the pollution-rich lower segments of clouds. The lowest Be concentrations were detected in the soluble fraction of snow. Across the sites, 34% of total Be deposition occurred in the form of soluble (bioavailable) Be, the rest were insoluble particles. Beryllium fluxes decreased in the order: vertical dry deposition insoluble>vertical dry deposition soluble>horizontal deposition soluble>vertical wet deposition insoluble>vertical wet deposition soluble>horizontal deposition insoluble. The average contributions of these Be forms to total deposition were 56, 21, 8, 7, 5 and 3%, respectively. Sites in the northeast were more Be-polluted than the rest of the country with sources of pollution in industrial Silesia.

  11. Diffusion des rayonnements X et visibles ; microscopie en champ proche : utilisation comparée pour la caractérisation des surfaces

    NASA Astrophysics Data System (ADS)

    Tollens, E.; Menecier, S.; Haidar, Y.; Zerrouki, C.; Chassevent, M.; de Fornel, F.; Bonnet, J. J.

    2004-11-01

    Trois méthodes ont été utilisées pour caractériser la rugosité de quelques échantillons. Deux de ces méthodes sont basées sur la mesure du rayonnement diffusé (visible et X). La troisième utilise la microscopie en champ proche (MCP). Dans un premier temps, une comparaison des deux premières techniques a été menée en utilisant une même théorie vectorielle de la diffusion. Bien adaptée au domaine du visible, cette théorie peut aussi être utilisée dans le cas du rayonnement X. Les densités spectrales de puissance (dsp) de la rugosité, déterminées expérimentalement pour deux échantillons d'Alacrite XSH (alliage quaternaire à base de cobalt utilisé en métrologie des masses), montrent des allures identiques dans le cas du visible et du rayonnement X à des incidences très rasantes. Dans un deuxième temps, la hauteur quadratique moyenne δ , caractéristique de la rugosité de ces deux échantillons, a été déterminée de façon "directe" par microscopie en champ proche, et à partir des dsp pour les deux autres techniques. La restriction à une bande commune des fréquences spatiales accessibles à ces techniques, conduit à des valeurs de δ comparables aux incertitudes près. Une validation des mesures X ainsi faite, un accent est mis sur leur apport complémentaire par rapport au visible.

  12. Scavenging of atmospheric constituents in mixed phase clouds at the high-alpine site jungfraujoch—part II. Influence of riming on the scavenging of particulate and gaseous chemical species

    NASA Astrophysics Data System (ADS)

    Poulida, O.; Schwikowski, M.; Baltensperger, U.; Staehelin, J.; Gaeggeler, H. W.

    The importance of riming as transfer mechanism of pollutants from the atmosphere into the snow in mixed phase clouds was investigated at the Jungfraujoch (3450 m a.s.l), during two intensive measurement campaigns in April 1992 and in October-November 1993. Cloud water and bulk snow crystal samples were concurrently collected during precipitation events, and were chromatographically analyzed for inorganic ions. The extent of riming was determined from the collection of individual snow crystals on Formvar replicas. Relatively low degrees of riming were observed during all the events. The rimed mass fraction (RMF) was being used as a tool to determine the role of riming with respect to other scavenging processes. No significant difference between the early-spring and the early-winter events was found. The precipitation events were classified on the basis of the temporal changes of the number concentration of aerosol particles and the equivalent potential temperature during an event. When the site could be considered as a "closed system", meaning that there was no air mass change, and that all the physical processes were occurring in the air mass being sampled at the site, then a strong positive correlation between the RMF and the concentration ratios, R, of snow water to cloud water was found. In contrast, a lack of statistical correlation between the RMF and the ratios R was observed when the sampling site was an "open system", meaning that it was affected by the entrainment of a new air mass. The application of a simple physical scheme revealed that a linear relationship between RMF and R is expected, provided that the cloud water samples are representative of the air mass in which the snow crystals are generated. Further modification of this scheme provided a relationship for the assessment of the importance of riming as transfer mechanism. The riming process was found to be responsible for 82 (±17) % of Cl -, 49 (±31) % of NO- 3, 77 (±20) % of SO 2-4, 82 (±16

  13. Large grain instruction and phonological awareness skill influence rime sensitivity, processing speed, and early decoding skill in adult L2 learners

    PubMed Central

    Brennan, Christine; Booth, James R.

    2016-01-01

    Linguistic knowledge, cognitive ability, and instruction influence how adults acquire a second orthography yet it remains unclear how different forms of instruction influence grain size sensitivity and subsequent decoding skill and speed. Thirty-seven monolingual, literate English-speaking adults were trained on a novel artificial orthography given initial instruction that directed attention to either large or small grain size units (i.e., words or letters). We examined how initial instruction influenced processing speed (i.e., reaction time (RT)) and sensitivity to different orthographic grain sizes (i.e., rimes and letters). Directing attention to large grain size units during initial instruction resulted in higher accuracy for rimes, whereas directing attention to smaller grain size units resulted in slower RTs across all measures. Additionally, phonological awareness skill modulated early learning effects, compensating for the limitations of the initial instruction provided. Collectively, these findings suggest that when adults are learning to read a second orthography, consideration should be given to how initial instruction directs attention to different grain sizes and inherent phonological awareness ability. PMID:27829705

  14. Large grain instruction and phonological awareness skill influence rime sensitivity, processing speed, and early decoding skill in adult L2 learners.

    PubMed

    Brennan, Christine; Booth, James R

    2015-09-01

    Linguistic knowledge, cognitive ability, and instruction influence how adults acquire a second orthography yet it remains unclear how different forms of instruction influence grain size sensitivity and subsequent decoding skill and speed. Thirty-seven monolingual, literate English-speaking adults were trained on a novel artificial orthography given initial instruction that directed attention to either large or small grain size units (i.e., words or letters). We examined how initial instruction influenced processing speed (i.e., reaction time (RT)) and sensitivity to different orthographic grain sizes (i.e., rimes and letters). Directing attention to large grain size units during initial instruction resulted in higher accuracy for rimes, whereas directing attention to smaller grain size units resulted in slower RTs across all measures. Additionally, phonological awareness skill modulated early learning effects, compensating for the limitations of the initial instruction provided. Collectively, these findings suggest that when adults are learning to read a second orthography, consideration should be given to how initial instruction directs attention to different grain sizes and inherent phonological awareness ability.

  15. Influence du traitement ionisant par rayonnement γ sur le pouvoir antioxydant de fractions polyphénoliques issues de substances d'origine végétale

    NASA Astrophysics Data System (ADS)

    Stuyck, S.; Connaulte, J.; Lesgards, G.; Prost, M.; Raffi, J.

    1998-04-01

    Ionizing radiation of vegetables is a cleaning up and preservation physical treatment which consists in submitting them to γ radiation, X radiation or electrons beam. This study deals with the influence of γ radiation on antioxidative effect of vegetables polyphenolic parts. In that purpose, we use a simple biological test based on erythrocytes haemolysis. Le traitement ionisant des produits végétaux est un procédé physique d'assainissement et de conservation qui consiste à les soumettre à l'action de rayonnements γ, de rayons X ou de faisceaux d'électrons. Ce travail porte sur l'étude de l'influence des rayonnements γ sur le pouvoir antioxydant de fractions polyphénoliques issues de substances d'origine végétale. Pour cela, un test biologique basé sur l'hémolyse d'érythrocytes est utilisé.

  16. Etude du Photochromisme et de la Photorefractivite dans le Poly

    NASA Astrophysics Data System (ADS)

    Ghailane, Fatima

    1995-11-01

    Nous avons etudie la possibilite d'utiliser un materiau organique, le poly(vinylcarbazole) comme milieu de stockage optique de masse en temps reel. Ce materiau dope aux photochromes presente un potentiel non negligeable pour l'holographie de volume en temps reel. Plusiers cycles, Ecriture-Lecture-Effacement, ont ete enregistres dans cette matrice polymerique avec une resolution assez elevee. Une etude a ete menee afin d'obtenir la valeur des parametres comme l'epaisseur du film et l'intensite d'ecriture pour un angle d'enregistrement theta_{ acute ecriture} donne qui permettent d'obtenir les meilleures efficacites diffractionelles tout en preservant ce milieu de tout effet de fatigue ou de degradation. Ce polymere devient photorefractif une fois melange avec un bon accepteur de charge, le trinitrofluorenone et un bon chromophore non-lineaire, le disperse orange 25. Nous avons etudie experimentalement la conductivite en obscurite et la photoconductivite de ce materiau. Des simulations numeriques ont ete realisees en se basant sur le modele de Poole-Frenkel. Nous avons aussi etudie l'implantation de faisceaux d'ions d'oxygene d'energie 200 keV pour inscrire dans le PVCz un guide d'onde plan a profil d'indice. Une etude ESCA complete cette partie afin de savoir les modifications induites par implementation ionique a l'interieur du film polymerique.

  17. Cu-Zn isotope constraints on the provenance of air pollution in Central Europe: Using soluble and insoluble particles in snow and rime.

    PubMed

    Novak, Martin; Sipkova, Adela; Chrastny, Vladislav; Stepanova, Marketa; Voldrichova, Petra; Veselovsky, Frantisek; Prechova, Eva; Blaha, Vladimir; Curik, Jan; Farkas, Juraj; Erbanova, Lucie; Bohdalkova, Leona; Pasava, Jan; Mikova, Jitka; Komarek, Arnost; Krachler, Michael

    2016-11-01

    Copper (Cu) and zinc (Zn) isotope ratios can be used to fingerprint sources and dispersion pathways of pollutants in the environment. Little is known, however, about the potential of δ(65)Cu and δ(66)Zn values in liquid and solid forms of atmospheric deposition to distinguish between geogenic, industrial, local and remote sources of these potentially toxic base metals. Here we present Cu-Zn deposition fluxes at 10 mountain-top sites in the Czech Republic, a region affected by extremely high industrial emission rates 25 years ago. Additionally, we monitored isotope composition of Cu and Zn in vertical and horizontal atmospheric deposition at two sites. We compared δ(65)Cu and δ(66)Zn values in snow and rime, extracted by diluted HNO3 and concentrated HF. Cu and Zn isotope signatures of industrial pollution sources were also determined. Cu and Zn deposition fluxes at all study sites were minute. The mean δ(65)Cu value of atmospheric deposition (-0.07‰) was higher than the mean δ(65)Cu value of pollution sources (-1.17‰). The variability in δ(65)Cu values of atmospheric deposition was lower, compared to the pollution sources. The mean δ(66)Zn value of atmospheric deposition (-0.09‰) was slightly higher than the mean δ(66)Zn value of pollution sources (-0.23‰). The variability in δ(66)Zn values of atmospheric deposition was indistinguishable from that of pollution sources. The largest isotope differences (0.35‰) were observed between the insoluble and soluble fractions of atmospheric deposition. These differences may result from different sources of Cu/Zn for each fraction. The difference in isotope composition of soluble and insoluble particles appears to be a promising tool for pollution provenance studies in Central Europe.

  18. Survey of Hyperspectral and Multispectral Imaging Technologies (Etude sur les technologies d’imagerie hyperspectrale et multispectrale)

    DTIC Science & Technology

    2007-05-01

    SET-065-P3 Survey of Hyperspectral and Multispectral Imaging Technologies ( Etude sur les technologies d’imagerie hyperspectrale et multispectrale... Etude sur les technologies d’imagerie hyperspectrale et multispectrale) This Report forms part of RTG-33’s activities in assessing...that will guarantee a solid base for the future. The content of this publication has been reproduced directly from material supplied by RTO or the

  19. Analyse de l'intensité de fluorescence émise par une multicouche périodique sous rayonnement synchrotron. Application à l'étude de la répartition spatiale des éléments dans l'empilement

    NASA Astrophysics Data System (ADS)

    Bridou, F.; Cauchon, G.; Idir, M.

    2004-11-01

    L'analyse de l'intensité du rayonnement de fluorescence des multicouches périodiques en fonction des angles d'incidence ou d'émission, peut constituer une méthode de caractérisation non destructive capable de déterminer le profil de concentration en profondeur d'un élément donné, notamment au niveau des interfaces où ce profil influe considérablement sur les performances optiques dans le domaine X-UV. Le principe de la méthode consiste à exciter la fluorescence d'un des deux matériaux de l'empilement par une radiation d'énergie supérieure à celle du seuil d'absorption de l'élément considéré. Celui-ci va émettre son propre rayonnement à l'intérieur de la multicouche. La répartition d'intensité est modulée selon la distribution géométrique des sources de rayonnement (donc de l'élément excité) à l'intérieur de l'empilement. On présente ici les résultats qui ont pu êtres obtenus à partir du rayonnement d'une source synchrotron (SB3_LURE) pour étudier une multicouche Mo/Si de 50 périodes. On a pu ainsi exciter d'une part la fluorescence du silicium, puis celle du molybdène, et montrer que les informations obtenues sur la répartition des éléments dans la multicouche étaient complémentaires.

  20. Etude sur les tendons en materiaux composites et leur application aux ancrages postcontraints

    NASA Astrophysics Data System (ADS)

    Chennouf, Adil

    L'objectif general de la presente these est d'evaluer le comportement a l'arrachement et au fluage d'ancrages injectes constitues de tendons en materiaux composites afin d'etablir des recommandations plus appropriees et realistes pour le dimensionnement et la conception. Quatre types de tendons en materiaux composites, deux a base de fibres d'aramide et deux a base de fibres de carbone, ont ete utilises dans l'etude. Les travaux de recherche de cette these ont porte notamment sur: (I) Une caracterisation physique et mecanique des tendons en materiaux composites utilises dans l'etude. (II) Une etude en laboratoire sur les coulis de scellement. La premiere etape de cette etude a concerne le developpement d'un coulis de scellement performant adapte aux tendons en materiaux composites et a differentes situations d'injection. La seconde etape a traite des essais de caracterisations physique et mecanique du coulis de scellement developpe comparativement a trois coulis de scellement usuels d'un meme rapport E/L de 0,4. (III) Une etude sur des modeles reduits d'ancrages injectes. (IV) Une etude sur des modeles d'ancrages a grande echelle. La synthese de ces etudes a permis d'enoncer les principales conclusions suivantes: (1) Les valeurs moyennes des charges de rupture des tendons en materiaux composites ont ete de 1% a 29% superieures a celles specifiees par les manufacturiers. (2) L'etude sur les coulis de scellement a permis le developpement de coulis de ciment repondant aux criteres fixes, soient une grande stabilite, une bonne fluidite, une legere expansion et de bonnes caracteristiques mecaniques. (3) Les tendons en materiaux composites ont montre des contraintes d'adherence maximum superieures a celles des tendons en acier. (4) Le type de fibre, la configuration et le fini de surface des tendons en materiaux composites gouvernent leur resistance a l'adherence. (5) L'introduction de sable et d'autres ajouts comme les fines de silice et la poudre d'aluminium au coulis

  1. Singing as a Therapeutic Agent, inThe Etude, 1891-1949.

    PubMed

    Hunter

    1999-01-01

    The Etude music magazine, founded by Theodore Presser, was one of a number of popular music magazines published in the years prior to the establishment of the music therapy profession in 1950. During its publication run from 1883 to 1957, over 100 music therapy related articles appeared, including 13 on the health benefits of singing published between 1891 and 1949. Written by authors with diverse backgrounds, such as the famous Battle Creek, Michigan physician John Harvey Kellogg and Boston music critic Louis C. Elson, the articles contained consistent and adamant support regarding the health benefits of singing. The advantages described were both physical and psychological, and were recommended prophylactically for well persons and therapeutically for ill persons. Although the articles varied in perspective, from philosophical to theoretical to pedagogical, there is a consistent holistic medicine theme that appeared almost ahead of its time and no doubt linked to the push for vocal music education in that era. The importance of The Etude in promulgating ideas that helped shape the early practice of music therapy should not be underestimated. For much of its publication run The Etude was the largest music periodical in print, reaching its peak circulation of 250,000 copies per month in 1924.

  2. Etude theorique des fluctuations structurales dans les composes organiques a dimensionnalite reduite

    NASA Astrophysics Data System (ADS)

    Dumoulin, Benoit

    Les systemes a dimensionnalite reduite constituent maintenant une branche entiere de la physique de la matiere condensee. Cette derniere s'est developpee rapidement au cours des dernieres annees, avec la decouverte des materiaux organiques qui presentent, justement, des proprietes physiques fortement anisotropes. Cette these presente une etude en trois parties de plusieurs composes organiques qui, bien que tres differents du point de vue de leurs compositions chimiques et de leurs proprietes physiques a haute temperature, subissent tous une instabilite structurale a tres basse temperature. De plus, dans chacun des cas, l'instabilite structurale est precedee d'un important regime fluctuatif a partir duquel les proprietes physiques changent de maniere significative. Notre etude suit un ordre chronologique inverse puisque nous nous attardons en premier lieu au cas de composes recemment decouverts: les composes de la famille des (BCPTTF)2X (X = PF6 , AsF6). Ces derniers sont des isolants magnetiques a la temperature ambiante et subissent une instabilite structurale de type spin-Peierls a une temperature appelee TSP. En particulier, nous nous interessons a l'etude des proprietes physiques de ces systemes dans le regime fluctuatif, qui precede cette instabilite. Notre etude theorique nous permet de comprendre en detail comment ces systemes s'approchent de l'instabilite struturale. Dans la seconde partie de cette these, nous etudions le regime fluctuatif (pre-transitionnel) observe experimentalement dans le compose de (TMTTF)2PF6. Ce compose organique, dont la structure s'apparente aux sels de Bechgaard, subit une instabilite de type spin-Peierls a une temperature T SP = 19K. Bien que ce compose possede la particularite d'etre un bon conducteur a la temperature ambiante, il subit une transition de type Mott-Hubbard a une temperature Trho ≈ 220K et devient alors un isolant magnetique, analogue aux composes de la famille des (BCPTTF)2X. Le regime fluctuatif precedant l

  3. Etude des émissions radio aurorales de Saturne, modélisation et aurores UV

    NASA Astrophysics Data System (ADS)

    Lamy, Laurent

    2008-09-01

    Cette thèse porte sur l'étude du rayonnement radio auroral kilométrique de Saturne (SKR pour Saturn Kilometric Radiation) observé de façon quasi-continue par les antennes radio de la sonde Cassini depuis son entrée en orbite autour de Saturne en juillet 2004. Comme les rayonnements radio auroraux des autres planètes magnétisées, le SKR est généré sur des lignes de champ magnétique de haute latitude prés des pôles magnétiques. Tirant parti de plusieurs années d'observations, les propriétés macroscopiques du SKR (spectre, polarisation, conjuguaison des sources de chaque hémisphère, mode d'émission) sont déduites par une analyse statistique. Elles montrent en particulier que les caractéristiques de l'émission dépendent fortement de la position de l'observateur. Ceci est une conséquence directe de l'anisotropie du SKR qui engendre de forts effets de visibilité, visibles dans les cartes d'intensité temps-fréquence (arcs, régions d'invisibilité de l'émission). La simulation de ces effets de visibilité apporte de nouvelles contraintes sur les propriétés microscopiques des sources (énergie et distribution des électrons auroraux). Le SKR est connu pour être modulé à une période variable. Une analyse de la variation de cette période radio sur plusieurs années révèle des oscillations à court terme de l'ordre de 20-30 jours dont l'origine est attribuée à la variation de la vitesse caractéristique du vent solaire au niveau de Saturne. Une étude parallèle du rayonnement auroral kilométrique terrestre (AKR), observé lors du survol de la Terre par Cassini en août 1999, met en évidence la découverte d'une modulation diurne semblable à celle du SKR. Enfin, la technique de goniopolarimétrie permet de faire de l'imagerie radio des sources du SKR. L'étude de leur distribution moyenne montre pour la première fois l'existence d'un ovale radio. La comparaison des images des sources du SKR avec celles des ovales auroraux (observ

  4. Contributions a L'etude de Dispositifs D'optique Integree

    NASA Astrophysics Data System (ADS)

    Touam, Tahar

    Cette these contient des contributions a l'etude de deux champs du vaste domaine de l'optique integree. A cet effet, nous avons divise notre travail en deux grandes parties:. Dans une premiere partie, nous traitons le probleme de la realisation d'une nouvelle classe de guides d'onde planaires utilisables dans le domaine de longueur d'onde de l'infrarouge moyen (infrarouge thermique), domaine ou l'apparition anticipee de fibres optiques a pertes extremement faibles rendraient fort interessante l'existence de tels guides d'onde planaires. Dans un premier temps, nous presentons une etude analytique originale d'une structure planaire a profil d'indice gradue, suivie d'une analyse d'un guide canal base sur cette structure. Dans un deuxieme temps, nous decrivons le procede de fabrication par pulverisation atomique d'un guide planaire forme d'arseniure de gallium (AsGa) sur du dioxyde de silicium (SiO_2 ), combinaison de materiau compatible avec l'infrarouge moyen. Finalement, nous presentons une etude de conception d'un reseau de surface destine a coupler la lumiere dans un tel guide, les autres methodes traditionnelles de couplage semblant peu appropriees aux environs de lambda = 10 mum. Dans une deuxieme partie, nous traitons le probleme de la jonction Y en optique integree, jonction qui soufre de pertes tres importantes des que l'angle d'ouverture devient interessant pour le concepteur de circuits integres optiques. L'analyse est basee sur la methode numerique dite BPM (Beam Propagation Method; methode de propagation du faisceau) qui fait l'objet d'un bref rappel. Nous poursuivons avec l'etude et l'optimisation d'une nouvelle jonction Y dont l'essence est l'utilisation du phenomene de diffraction a travers trois fentes de phase. Nous obtenons ainsi une tres bonne jonction, separant proprement le faisceau, a une ouverture de 10 degres. Finalement, nous faisons un rappel d'un profil d'indice dit "ideal" pour guides courbes et nous proposons l'utilisation de tels guides

  5. Etude des chaines de spins par les methodes de la theorie quantique des champs

    NASA Astrophysics Data System (ADS)

    Allen, Dave

    Notre etude porte sur la chaine de spins en zigzag avec dimerisation dans le cas des spins 1/2 et 1. L'echelle de spin ordinaire et la chaine en zigzag simple en sont des cas particuliers. Dans la limite continue, ces systemes sont decrits par des modeles Wess-Zumino-Witten couples. Afin de pouvoir calculer les fonctions de correlation, nous exposons differentes equivalences quantiques permettant de simplifier les calculs. Dans le cas de chaines de spin 1/2, nous demontrons l'equivalence avec un modele de type Gross-Neveu, en fonction de fermions de Majorana; ces fermions decrivent alors les excitations elementaires du systeme. Nous exposons une vision classique de ces excitations afin de voir les mecanismes de confinement des spinons. Dans le cas de chaines de spin 1, l'etude est plus complexe. Nous pouvons decrire le systeme a l'aide de modeles sine-Gordon perturbes par de nombreuses interactions. En se limitant aux plus importantes, nous pouvons expliquer le comportement du gap en fonction du couplage interchaine observe numeriquement.

  6. Overview of ICF program at Centre D{close_quote}Etudes de Limeil-Valenton

    SciTech Connect

    Cel-V Laser Team

    1996-05-01

    The major objectives of the CEA-DAM laser program is to determine the various requirements to achieve thermonuclear fusion in laboratory. We report here recent results obtained at Centre d{close_quote}Etudes de Limeil-Valenton on high density X-Ray implosions, radiative transfer processes, hydrodynamic instabilities and laser-plasma interaction involved in cavity physics. Ignition and a moderate gain appears to be achievable with a laser energy of about 1.5{minus}2 MJ delivered at {lambda}=0, 35 {mu}m with a shaped pulse (duration{approximately}16 ns). The construction of such a laser is realizable and a conceptual design is under preparation. {copyright} {ital 1996 American Institute of Physics.}

  7. Etudes Asymptotiques en Filtrage Non Lineaire Avec Petit Bruit D’Observation (Asymptotic Studies in Nonlinear Time Filtering with Small Observation Noise)

    DTIC Science & Technology

    1990-09-26

    titre de s DOCTEUR DE L’UNIVERSITE DE PROVENCE : SpdcialitM MATHEMATIQUES APPLIQUEES par PAULA M. L. P. MILHEIRO de OLIVEIRA Sujet de la these: ETUDES...PROVENCE Spdcialitd: MATHEMATIQUES APPLIQUEES par PAULA M. L. P. MILHEIRO de OLIVEIRA Sujet dela thse: E~TUDES ASYMPTOTIQUES EN FILTRAGE NON LINEAIRE...At Pk + h2 At p,]f6 2 ± h2 AtP] k CO lk + Ilk Donc C I~k+1 Pk1 (10) 1-iPk + C Cl Suivant un raisonnement par recurrence on trouve l’expression: Ilk_

  8. Etude paleomagnetique des sediments holocenes de la Fosse du Mackenzie, mer de Beaufort

    NASA Astrophysics Data System (ADS)

    Barris, Elissa

    Les etudes paleomagnetiques a haute resolution sont d'importance en magnetostratigraphie et geomagnetisme, particulierement dans l'Arctique en raison de l'inaccessibilite et des faibles vitesses de sedimentation dans plusieurs secteurs. Deux carottes sedimentaires representant l'Holocene recent ont ete recoltees dans la Fosse du Mackenzie, une region avec des vitesses de sedimentation relativement elevees. Une carotte boite et un Calypso square core ont ete preleves a deux sites (690 et 680). Les proprietes physiques et magnetiques et la granulometrie ont ete mesurees, ainsi que les aimantations remanentes naturelle, anhysteretique, isothermale et isothermale saturee (NRM, ARM, IRM et SIRM). L'hysteresis magnetique indique une forte concentration de magnetite de type pseudo-single domain, un porteur ideal de remanence, alors que les mesures de la susceptibilite magnetique suggerent une concentration uniforme. Les valeurs de deviation angulaire maximale (MAD) et du champ median destructif (MDF) indiquent des donnees de direction d'excellente qualite et une coercivite typique de la magnetite, respectivement. Finalement, dans la carotte 690 et la partie intermediaire de la 680, l'inclinaison vane autour des valeurs d'un dipole axial geocentrique (GAD) pour la latitude des sites, renforcant la fiabilite du signal paleomagnetique. Finalement, des proxies de la paleointensite relative ont ete construits pour les carottes 690 et 680 en normalisant la NRM par l'IRM et l'ARM, respectivement. Vingt-et-une coquilles de pelecypodes reparties dans les deux carottes ont ete recoltees pour construire un modele d'âge au radiocarbone a chaque si te, une tâche necessaire pour la mise en contexte d'un enregistrement paleomagnetique, mais souvent difficile dans l'Arctique. En utilisant ces modeles d'âge, les enregistrements paleomagnetiques ont ete compares avec d'autres provenant du bas-Arctique et des moyennes latitudes, soulignant leur potentiel pour des etudes

  9. Gastrointestinal lymphomas: the French experience of the Groupe D'etude des Lymphomes Digestifs (GELD).

    PubMed

    Ruskoné-Fourmestraux, A

    2000-01-01

    Since 1983, the French Groupe d'Etude des Lymphomes Digestifs (GELD), under the aegis of the Fondation Française de Cancérologie Digestive, has aimed to identify the different prognostic groups of the primary digestive-tract lymphomas (PDTL) and their optimal treatment. Successive multicenter studies were conducted and 91 PDTL were evaluated. A marked improvement in their prognosis was obtained by a strategy including precise histologic typing and clinical staging followed by a therapeutic approach combining initial surgical resection, whenever possible or reasonable, followed by chemotherapy adapted to the grade of malignancy and resectability of the lymphoma. The multivariate analysis indicated that the factors for good prognosis were age (< 65 yrs), gastric localisation, stage IE and radical or even incomplete surgery. However, Helicobacter pylori eradication should be the first treatment in stage IE low-grade gastric mucosa-associated lymphoid tissue (MALT) tumors. The long-term results of such medical treatment are evaluated together with the management and the place of surgery in these localised tumors. However, owing to the limited number of patients, a large international co-operative trial is needed to confirm the findings. Thirty-one cases of multiple lymphomatous polyposis were also collected and confirmed to be a distinct entity among PDTL and the gastrointestinal counterpart of the mantle-cell-zone lymphomas. High-dose radio-chemotherapy supported by auto-transplantation improved their prognosis.

  10. Long homozygous chromosomal segments in reference families from the centre d'Etude du polymorphisme humain.

    PubMed

    Broman, K W; Weber, J L

    1999-12-01

    Using genotypes from nearly 8,000 short tandem-repeat polymorphisms typed in eight of the reference families from the Centre d'Etude du Polymorphisme Humain (CEPH), we identified numerous long chromosomal segments of marker homozygosity in many CEPH individuals. These segments are likely to represent autozygosity, the result of the mating of related individuals. Confidence that the complete segment is homozygous is gained only with markers of high density. The longest segment in the eight families spanned 77 cM and included 118 homozygous markers. All individuals in family 884 showed at least one segment of homozygosity: the father and mother were homozygous in 8 and 10 segments with an average length of 13 and 16 cM, respectively, and covering a total of 105 and 160 cM, respectively. The progeny in family 884 were homozygous over 5-16 segments with average length 11 cM. The progeny in family 102 were homozygous over 4-12 segments with average length 19 cM. Of the 100 individuals in the other six families, 1 had especially long homozygous segments, and 19 had short but significant homozygous segments. Our results indicate that long homozygous segments are common in humans and that these segments could have a substantial impact on gene mapping and health.

  11. Etude vibroacoustique d'un systeme coque-plancher-cavite avec application a un fuselage simplifie

    NASA Astrophysics Data System (ADS)

    Missaoui, Jemai

    L'objectif de ce travail est de developper des modeles semi-analytiques pour etudier le comportement structural, acoustique et vibro-acoustique d'un systeme coque-plancher-cavite. La connection entre la coque et le plancher est assuree en utilisant le concept de rigidite artificielle. Ce concept de modelisation flexible facilite le choix des fonctions de decomposition du mouvement de chaque sous-structure. Les resultats issus de cette etude vont permettre la comprehension des phenomenes physiques de base rencontres dans une structure d'avion. Une approche integro-modale est developpee pour calculer les caracteristiques modales acoustiques. Elle utilise une discretisation de la cavite irreguliere en sous-cavites acoustiques dont les bases de developpement sont connues a priori. Cette approche, a caractere physique, presente l'avantage d'etre efficace et precise. La validite de celle-ci a ete demontree en utilisant des resultats disponibles dans la litterature. Un modele vibro-acoustique est developpe dans un but d'analyser et de comprendre les effets structuraux et acoustiques du plancher dans la configuration. La validite des resultats, en termes de resonance et de fonction de transfert, est verifiee a l'aide des mesures experimentales realisees au laboratoire.

  12. Etude theorique et experimentale des evaporateurs de dioxyde de carbone operant dans des conditions de givrage

    NASA Astrophysics Data System (ADS)

    Bendaoud, Adlane Larbi

    Les evaporateurs de refrigeration sont surtout du type tube a ailettes, appeles serpentins, et fonctionnent dans l'une des conditions suivantes: seche, humide ou avec formation de givre. Il a ete demontre que la formation du givre sur la paroi exterieure de l'echangeur engendre une surconsommation energetique a cause des operations de degivrage puisque 15 a 20% seulement de la chaleur produite sert au degivrage tandis que le reste est dissipee dans l'environnement [1]. Avec l'avenement des nouveaux refrigerants, moins nocifs envers l'environnement, l'industrie du froid se trouve penalisee du fait que peu ou pas de composantes mecaniques (compresseur, pompe, echangeur...etc.) adaptees sont disponibles [3]. Il s'agit pour la communaute des frigoristes de combler ce retard technologique en redeveloppant ces composantes mecaniques afin qu'elles soient adaptees aux nouveaux refrigerants. Dans cette optique, et afin de mieux comprendre le comportement thermique des evaporateurs au CO2 fonctionnant dans des conditions seches, qu'un groupe de chercheurs du CanmetENERGIE avaient lance, en 2000, un programme de R & D. Dans le cadre de programme un outil de simulation des evaporateurs au CO2 a ete developpe et un banc d'essai contenant une boucle secondaire de refrigeration utilisant le CO2 comme refrigerant a ete construit. Comme continuite de ce travail de recherche, en 2006 ce meme groupe de recherche a lance un nouveau projet qui consiste a faire une etude theorique et experimentale des evaporateurs au CO2 operants dans des conditions de givrage. Et, c'est exactement dans le cadre de ce projet que se positionne ce travail de these. Ce travail de recherche a ete entrepris pour mieux comprendre le comportement thermique et hydrodynamique des serpentins fonctionnant dans des conditions de givrage, l'effet des circuits de refrigerant ainsi que celui des parametres geometriques et d'operation. Pour cela, un travail theorique supporte par une etude experimentale a ete effectue

  13. Caracterisation des etats de surface par teledetection infrarouge thermique multispectrale: Contribution a l'etude des conditions de viabilite hivernale

    NASA Astrophysics Data System (ADS)

    Chagnon, Frederic

    La mesure de temperature d'une surface et de son emissivite thermique constitue encore de nos jours, un defi de taille. D'un point de vue microclimatique, la temperature significative d'une surface est celle qui reflete l'etat des echanges energetiques qui y ont lieu. La radiometrie infrarouge thermique permet de lire la temperature de l'interface air-sol pour une couche infiniment petite de la surface (de l'ordre de quelques microns). Dans le cadre d'un systeme d'aide aux decisions en viabilite hivernale, nous avons defini un prototype de station de mesures mobiles. Cette station permet de determiner, avec precision, la temperature radiative de la surface de la chaussee ainsi que de determiner, avec un taux de succes de plus de 65 %, l'etat de cette meme surface. Par la conception de ce prototype, nous avons aborde le principe physique de la mesure de temperature de surface par radiometrie multispectrale infrarouge thermique. Ce travail aura permis d'evaluer une approche standard de mesure a bande spectrale unique (de 8 a 14 mum). Dans la correction de la temperature radiative de surface, nous avons considere trois methodes distinctes. La premiere methode utilisee est celle de l'algorithme TES (Gillespie et al., 1998). Cet algorithme etablit le spectre d'emissivite, puis calcule une temperature de surface corrigee, en tenant compte de la reflexion du rayonnement thermique incident a la surface. La seconde methode consideree est l'indice TISI (Li et al., 1999) qui consiste en un indice d'emissivite relatif independant de la temperature de la surface et qui tient compte du rayonnement incident a la surface. La troisieme methode est un indice de temperature relative (ITR) qui correspond au contraste normalise des temperatures radiatives de surface. L'identification du type de surface a montre un taux de succes de 54,8 % pour les resultats de l'indice ITR, de 51,9 % pour les resultats de l'indice TISI et de 67,3 % pour les resultats de l'algorithme TES. Quant a la

  14. Etude des proprietes electroniques des etats fondamentaux aux facteurs de remplissage entiers dans la bicouche de graphene

    NASA Astrophysics Data System (ADS)

    Lemonde, Marc-Antoine

    Dans ce document, on etudie les proprietes electroniques d'un systeme compose de deux couches de graphene separees par un dielectrique en presence d'un fort champ magnetique perpendiculaire. L'epaisseur du dielectrique est choisie de facon a pouvoir negliger le transfert de charges par effet tunnel. Ce type de systeme est etudie par quelques groupes de recherche dans le principal but de predire et comprendre la formation de condensat de Bose-Einstein d'excitons dont les composants sont des fermions relativistes sans masse [1] [2] [3]. Nous nous interessons a l'effet de l'interaction electron-electron sur les etats fondamentaux de ce systeme et 'a leurs excitations collectives a facteur de remplissage entier. Plus precisement, nous etudions les diagrammes de phase de cette bicouche de graphene sans terme tunnel dans le niveau de Landau n = 0 pour les facteurs de remplissage nu = 1 et nu = 2 dans la limite ou la temperature tend vers zero. Lors de cette etude, nous appuyons les predictions faites par Allan H. MacDonald et Yogesh N. Joglekar a propos de la formation d'un condensat de Bose-Einstein d'excitons pour differentes zones des diagrammes de phase. Nous etudions aussi la relation de dispersion des excitations collectives soutenues par les etats fondamentaux et leur effet sur le systeme. Finalement, nous nous interessons a la conductivite du systeme. Nous demontrons alors les regles de selection pour l'absorption inter-niveaux de Landaux et nous etudions l'effet des modes collectifs sur l'absorption .intrarniveau de Landau, Ce dernier phenomene ressort directement de la forme particuliere du reseau atomique du graphene et nous proposons dans ce document une toute premiere etude de ce concept. Mots-cles : graphene, gaz d'electrons bidimensionnel, effets Hall quantiques, proprietes electroniques, modes collectifs

  15. Etude Exploratoire sur l’Etat de Stress Post-Traumatique dans Deux Unites Operationnelles de l’Armee de Terre (Exploratory Study of the Condition of Post-Traumatic Stress Disorder from Two Operational Units of Ground Forces)

    DTIC Science & Technology

    2006-04-01

    RTO-MP-HFM-134 30 - 1 Etude exploratoire sur l’état de stress post-traumatique dans deux unités opérationnelles de l’armée de terre D ...Leur diagnostic nécessite une démarche active du médecin. L’objectif de l’étude vise à évaluer la fréquence de cette pathologie dans une population...d’inhibition (1). Cette pathologie a fréquemment une évolution chronique. Elle peut être très invalidante. Vallet, D .; Arvers, P. (2006) Etude exploratoire

  16. La structure de l'eau liquide: Une etude thermique par spectroscopie infrarouge

    NASA Astrophysics Data System (ADS)

    Larouche, Pascal

    Le probleme de la structure de l'eau liquide est important car l'eau est le liquide le plus present sur Terre, et complexe, la quete d'un modele precis pour decrire comment fonctionne ce liquide ayant debute des la fin du dix-neuvieme siecle. Cette etude aborde ce probleme en etudiant l'effet de l'augmentation de la temperature sur H2O et D 2O purs a l'aide de la spectroscopie infrarouge. L'intervalle de temperatures scrute est 29--93.1°C. Les spectres enregistres sont des spectres MIR-ATR entre 650 et 6000 cm-1 . L'analyse par facteurs de ces donnees permet de montrer que deux et seulement deux facteurs principaux sont necessaires pour decomposer tous les spectres experimentaux. Ces resultats sont confirmes grace a l'analyse par facteurs de spectres de la region FIR. Par la suite, la transformation en spectres de la partie reelle n et imaginaire k de l'indice de refraction permet de combiner les donnees des regions MIR et FIR. Une fois ce calcul termine, les spectres de transmission complets de H 2O et D2O entre 25 et 90°C sont connus. Ils sont ensuite utilises pour calculer par extrapolation le spectre des especes constituant l'eau liquide, puis leur abondance en fonction de la temperature. L'extrapolation de ces abondances montre que les especes correspondent a des temperatures limites de --18 et 122°C. Par la suite, la decomposition gaussienne des spectres d'especes met en evidence la riche structure de ces objets et permet de demontrer que l'apparent deplacement du massif d'absorption OH (OD) est produit par une variation de l'intensite des bandes et non pas de leur deplacement. L'examen attentif des spectres des especes prouve qu'il n'y a pas de OH libres crees par l'augmentation de la temperature: meme a 93.1°C, chaque molecule possede quatre liens-H. Ces conclusions sont de plus confirmees par une analyse thermodynamique du passage des molecules de la phase solide a la phase gazeuse. Pour diversifier la nature des resultats experimentaux utilises, des

  17. Etude par spectroscopie de Coulomb de points quantiques lateraux individuels et couples

    NASA Astrophysics Data System (ADS)

    Pioro-Ladriere, Michel

    Des points quantiques contenant un nombre discret et variable d'electrons sont formes dans un gaz bi-dimensionnel d'electrons a l'aide de grilles metalliques. Le transport electrique, le blocage de spin et la detection de charge sont employes comme outils spectroscopiques permettant de sonder les proprietes de ces nanostructures. Ces techniques permettent aussi de controler exactement le nombres d'electrons confines dans des points quantiques individuels et couples en utilisant un patron de grille judicieux. Une technique de refroidissement en tension est developpee afin de minimiser les effets parasites du bruit telegraphique. Ce type de bruit de charge deteriore la stabilite des nanostructures laterales par l'activation d'un minuscule courant de fuite entre les grilles et le gaz bi-dimensionnel. Un modele expliquant le role du refroidissement en tension sur le courant de fuite est presente. L'activation du courant de fuite est confirmee par detection de charge. Les effets des interactions entre les electrons pieges dans un point quantique sont ensuite etudies dans un regime ou il est possible de comparer les resulats experimentaux avec ceux obtenus par diagonalisation exacte. L'etude demontre que la phase associee au facteur de remplissage nu = 2 est instable au-dessus d'un nombre critique d'electrons. Cette instabilite est confirmee experimentalement par blocage de spin. On demontre aussi l'existence d'etats correles dans le regime des renversements de spin, associe au passage de la phase nu = 2 a nu = 1. Les etats correles sont identifies par spectroscopie en transport non lineaire. Cette caracterisation du diagramme de phase de points individuels permet de coupler deux points quantiques configures a nu = 2. Pour ce regime, la nanostructure se comporte comme un systeme a deux niveaux pouvant contenir entre un et quatre electrons de valence et ce, meme si le nombre total d'electrons est plus eleve. Les degres de liberte de charge et de spin des deux points

  18. Etude de l'influence de la temperature et de l'humidite sur les proprietes mecaniques en traction des fibres de chanvre et de coco

    NASA Astrophysics Data System (ADS)

    Ho Thi, Thu Nga

    L'objectif de cette etude fut d'etablir l'effet de l'humidite et de la temperature sur la resistance en traction et le module elastique des fibres de chanvre et de coco. Deux etudes ont ete realisees afin d'atteindre cet objectif. La premiere vise l'absorption de l'humidite dans ces fibres en exposition dans l'air (de 0%RH a 80%RH) ainsi que l'absorption de l'eau dans ces fibres immergees dans l'eau aux differentes temperatures. La deuxieme consiste a mesurer la resistance en traction et le module elastique de ces fibres sous differentes conditions d'humidite et de temperature. En basant sur les resultats experimentaux obtenus, les methodes semi empiriques et de reseaux de neurones ont ete utilisees pour but de predire les proprietes en traction (resistance et module d'elasticite) des fibres de chanvre et de coco sous l'influence de l'humidite et de la temperature.

  19. Etude des phenomenes dynamiques ultrarapides et des caracteristiques impulsionnelles d'emission terahertz du supraconducteur YBCO

    NASA Astrophysics Data System (ADS)

    Savard, Stephane

    Les premieres etudes d'antennes a base de supraconducteurs a haute temperature critique emettant une impulsion electromagnetique dont le contenu en frequence se situe dans le domaine terahertz remontent a 1996. Une antenne supraconductrice est formee d'un micro-pont d'une couche mince supraconductrice sur lequel un courant continu est applique. Un faisceau laser dans le visible est focalise sur le micro-pont et place le supraconducteur dans un etat hors-equilibre ou des paires sont brisees. Grace a la relaxation des quasiparticules en surplus et eventuellement de la reformation des paires supraconductrices, nous pouvons etudier la nature de la supraconductivite. L'analyse de la cinetique temporelle du champ electromagnetique emis par une telle antenne terahertz supraconductrice s'est averee utile pour decrire qualitativement les caracteristiques de celle-ci en fonction des parametres d'operation tels que le courant applique, la temperature et la puissance d'excitation. La comprehension de l'etat hors-equilibre est la cle pour comprendre le fonctionnement des antennes terahertz supraconductrices a haute temperature critique. Dans le but de comprendre ultimement cet etat hors-equilibre, nous avions besoin d'une methode et d'un modele pour extraire de facon plus systematique les proprietes intrinseques du materiau qui compose l'antenne terahertz a partir des caracteristiques d'emission de celle-ci. Nous avons developpe une procedure pour calibrer le spectrometre dans le domaine temporel en utilisant des antennes terahertz de GaAs bombarde aux protons H+ comme emetteur et detecteur. Une fois le montage calibre, nous y avons insere une antenne emettrice dipolaire de YBa 2Cu3O7-delta . Un modele avec des fonctions exponentielles de montee et de descente du signal est utilise pour lisser le spectre du champ electromagnetique de l'antenne de YBa 2Cu3O7-delta, ce qui nous permet d'extraire les proprietes intrinseques de ce dernier. Pour confirmer la validite du modele

  20. Reconstruction de la surface de Fermi dans l'etat normal d'un supraconducteur a haute Tc: Une etude du transport electrique en champ magnetique intense

    NASA Astrophysics Data System (ADS)

    Le Boeuf, David

    Des mesures de resistance longitudinale et de resistance de Hall en champ magnetique intense transverse (perpendiculaire aux plans CuO2) ont ete effectuees au sein de monocristaux de YBa2Cu3Oy (YBCO) demacles, ordonnes et de grande purete, afin d'etudier l'etat fondamental des supraconducteurs a haute Tc dans le regime sous-dope. Cette etude a ete realisee en fonction du dopage et de l'orientation du courant d'excitation J par rapport a l'axe orthorhombique b de la structure cristalline. Les mesures en champ magnetique intense revelent par suppression de la supraconductivite des oscillations magnetiques des resistances longitudinale et de Hall dans YBa2Cu 3O6.51 et YBa2Cu4O8. La conformite du comportement de ces oscillations quantiques au formalisme de Lifshitz-Kosevich, apporte la preuve de l'existence d'une surface de Fermi fermee a caractere quasi-2D, abritant des quasiparticules coherentes respectant la statistique de Fermi-Dirac, dans la phase pseudogap d'YBCO. La faible frequence des oscillations quantiques, combinee avec l'etude de la partie monotone de la resistance de Hall en fonction de la temperature indique que la surface de Fermi d'YBCO sous-dope comprend une petite poche de Fermi occupee par des porteurs de charge negative. Cette particularite de la surface de Fermi dans le regime sous-dope incompatible avec les calculs de structure de bande est en fort contraste avec la structure electronique presente dans le regime surdope. Cette observation implique ainsi l'existence d'un point critique quantique dans le diagramme de phase d'YBCO, au voisinage duquel la surface de Fermi doit subir une reconstruction induite par l'etablissement d'une brisure de la symetrie de translation du reseau cristallin sous-jacent. Enfin, l'etude en fonction du dopage de la resistance de Hall et de la resistance longitudinale en champ magnetique intense suggere qu'un ordre du type onde de densite (DW) est responsable de la reconstruction de la surface de Fermi. L'analogie de

  1. Chromosomal mapping of human genes by radioactive hybridization of cDNAs to Centre d'Etude du Polymorphisme humain high density gridded filter sets.

    PubMed

    Claas, A; Savelyeva, L; Pillmann, A; Schwab, M

    2000-08-01

    Chromosomal assignment of human transcribed sequences has been done mainly by high throughput genome analysis in specialized genome centres and, in a more classical fashion, by fluorescence in-site hybridization (FISH) analysis. Not every laboratory has the ability to map cDNAs by FISH analysis. We here report a rapid mapping approach that is based on the hybridization of cDNA probes to high density gridded Centre d'Etude du Polymorphisme Humain filters followed by subsequent computational analysis by database searches in the internet. Not only transcribed sequences but also genomic DNA could be subjected to this mapping approach. The presented approach allows to map human transcribed and genomic DNAs within 1-3 days and with a high level of resolution that will constantly increase in line with the incorporation of data deriving from high throughput genome mapping.

  2. Randomized control trial for the assessment of the anti-albuminuric effects of topiroxostat in hyperuricemic patients with diabetic nephropathy (the ETUDE study).

    PubMed

    Kato, Sawako; Ando, Masahiko; Mizukoshi, Toshihiro; Nagata, Takanobu; Katsuno, Takayuki; Kosugi, Tomoki; Tsuboi, Naotake; Maruyama, Shoichi

    2016-05-01

    Proteinuria is an established risk factor for diabetic nephropathy. Recent studies indicate that some xanthine oxidase inhibitors have a renoprotective effect. The aim of this study was to assess whether topiroxostat reduces albuminuria in hyperuricemic patients with diabetic nephropathy and overt proteinuria. The ETUDE study is an ongoing 24-week, multicenter, open-label, randomized (1:1), parallel group study involving hyperuricemic patients with diabetic nephropathy (estimated glomerular filtration rate [eGFR] ≥ 20 mL/min/1.73 m(2)) and overt proteinuria (0.3 ≤ urine protein to creatinine ratio (UPCR) < 3.5 g/g Cr). Patients are randomly assigned to high dose (topiroxostat 160 mg daily) or low dose (topiroxostat 40 mg daily) on top of standard of care. The primary endpoint is the change in albuminuria indicated by urine albumin-to-creatinine ratio after 24 treated weeks relative to the baseline values. This trial was registered at the Japanese University Hospital Medical Information Network Clinical Trials Registry (UMIN-CTR: UMIN 000015403). The background, rationale, and study design of this trial are presented here. Seventy-six patients from four registered facilities have already been enrolled and received at least one dose of topiroxostat. This trial will end in 2017. The ETUDE trial is the first randomized controlled study of topiroxostat in hyperuricemic patients with diabetic nephropathy and overt proteinuria. We will clarify the pleiotropic function of topiroxostat including an anti-albumiuric effect as well as its effects on safely decreasing serum uric acid levels.

  3. Etude d'un systeme de recuperation et de stockage de chaleur pour un systeme eolien-diesel avec stockage d'air comprime

    NASA Astrophysics Data System (ADS)

    Remillon, Thibaut

    La recherche presentee dans ce memoire porte sur les systemes hybrides eolien-diesel avec stockage d'air comprime (SHEDAC) adaptes a la production d'electricite en sites isoles, et plus precisement sur l'apport d'un systeme de recuperation et de stockage de chaleur (TES) au fonctionnement de ces systemes. Le principe de fonctionnement est le suivant. Quand la puissance eolienne est excedentaire par rapport aux besoins de la charge, le surplus d'energie est utilise pour comprimer de l'air. De ce processus resulte un rechauffement de l'air, on choisit d'extraire et de stocker la chaleur separement. Lors de la phase de restitution d'energie, l'air comprime utilise pour suralimenter le moteur thermique est rechauffe en utili sant la chaleur stockee precedemment. Tout au long de l'etude, nous avons seulement pris en compte la chaleur provenant du processus de compression de l'air, et neglige en tous points du systeme les echanges de chaleur avec le milieu exterieur. Pour quantifier l'apport du systeme de stockage de chaleur, nous avons tout d'abord mene une etude bibliographique sur ces systemes, pour identifier les meilleures solutions disponibles. Ensuite, on a modelise une de ces solutions sous Simulink pour etudier son fonctionnement de maniere plus precise. D'autre part, on a modelise un systeme de stockage de chaleur ideal pour quantifier l'apport maximal d'un TES sur les performances du SHEDAC. Nous avons conclu que les TES les plus adaptes aux systemes SHEDAC etaient les solutions actives directes a deux reservoirs, et que, pour beneficier au maximum du systeme de stockage de chaleur, il etait interessant de realiser la detente de l'air comprime stocke dans un moteur a air comprime, pour maximiser la recuperation d'energie mecanique.

  4. Etude numerique et experimentale de la reponse vibro-acoustique des structures raidies a des excitations aeriennes et solidiennes

    NASA Astrophysics Data System (ADS)

    Mejdi, Abderrazak

    compte. Les modeles developpes ont permis de conduire plusieurs etudes parametriques sur les proprietes vibro-acoustiques des structures d'avions facilitant ainsi la tache des concepteurs. Dans le cadre de cette these, un article a ete publie dans le Journal of Sound and Vibration et trois autres soumis, respectivement aux Journal of Acoustical Society of America, International Journal of Solid Mechanics et au Journal of Sound and Vibration Mots cles : structures raidies, composites, vibro-acoustique, perte par transmission.

  5. L'etude de l'InP et du GaP suite a l'implantation ionique de Mn et a un recuit thermique

    NASA Astrophysics Data System (ADS)

    Bucsa, Ioan Gigel

    Cette these est dediee a l'etude des materiaux InMnP et GaMnP fabriques par implantation ionique et recuit thermique. Plus precisement nous avons investigue la possibilite de former par implantation ionique des materiaux homogenes (alliages) de InMnP et GaMnP contenant de 1 a 5 % atomiques de Mn qui seraient en etat ferromagnetique, pour des possibles applications dans la spintronique. Dans un premier chapitre introductif nous donnons les motivations de cette recherche et faisons une revue de la litterature sur ce sujet. Le deuxieme chapitre decrit les principes de l'implantation ionique, qui est la technique utilisee pour la fabrication des echantillons. Les effets de l'energie, fluence et direction du faisceau ionique sur le profil d'implantation et la formation des dommages seront mis en evidence. Aussi dans ce chapitre nous allons trouver des informations sur les substrats utilises pour l'implantation. Les techniques experimentales utilisees pour la caracterisation structurale, chimique et magnetique des echantillons, ainsi que leurs limitations sont presentees dans le troisieme chapitre. Quelques principes theoriques du magnetisme necessaires pour la comprehension des mesures magnetiques se retrouvent dans le chapitre 4. Le cinquieme chapitre est dedie a l'etude de la morphologie et des proprietes magnetiques des substrats utilises pour implantation et le sixieme chapitre, a l'etude des echantillons implantes au Mn sans avoir subi un recuit thermique. Notamment nous allons voir dans ce chapitre que l'implantation de Mn a plus que 1016 ions/cm 2 amorphise la partie implantee du materiau et le Mn implante se dispose en profondeur sur un profil gaussien. De point de vue magnetique les atomes implantes se trouvent dans un etat paramagnetique entre 5 et 300 K ayant le spin 5/2. Dans le chapitre 7 nous presentons les proprietes des echantillons recuits a basses temperatures. Nous allons voir que dans ces echantillons la couche implantee est polycristalline et les

  6. Etude Par Spectroscopie Infrarouge des Oxydes Moleculaires Superoxyde de Potassium, Peroxyde de Potassium et Trioxyde de Silicium Isoles EN Matrice D'argon

    NASA Astrophysics Data System (ADS)

    Tremblay, Benoit

    1995-01-01

    A l'aide de la spectroscopie d'absorption infrarouge et de la technique d'isolation en matrice d'argon, nous avons repris l'etude des differents oxydes moleculaires qui se forment lorsque l'oxygene moleculaire se trouve dans des agregats avec du potassium, du silicium et de l'oxyde de silicium SiO. Le choix des oxydes moleculaires KO_2 et K_2O_2 a ete motive par le fait qu'ils ont souvent ete mis en evidence dans tres travaux en physique des surfaces lors de letude du systeme O_2/K/Si. Ces oxydes avaient deja ete identifies par spectroscopie infrarouge en matrice d'argon au debut des annees soixante-dix. Pour KO_2, l'observation des modes nu_2 et nu_3 pour de nombreuses especes isotopiques nous a permis de deduire la longueur de la liaison K-O et de l'angle O-K-O. En effet, la construction d'un champ de force harmonique nous a permis de determiner sa structure et des constantes de force qui reprodusient tres bien les frequences experimentales observees. L'etude de l'oxyde K_2O _2 s'est averee interessante car avant notre travail, seule une vibration avait ete mise en evidence. Nous avons reussi a observer deux nouvelles vibrations fondamentales: une bande infrarouge faible a 185 cm^{-1}, avec les isotopes ^{16}O _2, ^{18}O _2 et ^{16} O^{18}O de l'oxygene, et une autre, activee en infrarouge avec l'isotope ^{16}O^{18 }O a 405 cm^{-1}. Les donnees experimentales etant insuffisantes pour deduire la structure de la molecule, des calculs theoriques avec la methode de la fonctionnelle de la densite ont donne le structure et les vibrations non observees du K _2O_2. Ces donnees supplementaires sont venues completer les resultats experimentaux et nous ont permis de construire un champ de force harmonique avec <=uel nous avons trouve des constantes de force qui reproduisent tres bien les frequences observees. Les calculs theoriques ont monte que K_2O _2 doit etre de structure C_ {rm 2v}, bien que la structure D _{rm 2h} ne puisse pas etre rejetee, puisque qu'il y a un

  7. Etudes optiques de nouveaux materiaux laser: Des orthosilicates dopes a l'ytterbium: Le yttrium (lutetium,scandium) pentoxide de silicium

    NASA Astrophysics Data System (ADS)

    Denoyer, Aurelie

    La decouverte et l'elaboration de nouveaux materiaux laser solides suscitent beaucoup d'interet parmi la communaute scientifique. En particulier les lasers dans la gamme de frequence du micron debouchent sur beaucoup d'applications, en telecommunication, en medecine, dans le domaine militaire, pour la, decoupe des metaux (lasers de puissance), en optique non lineaire (doublage de frequence, bistabilite optique). Le plus couramment utilise actuellement est le Nd:YAG dans cette famille de laser, mais des remplacants plus performants sont toujours recherches. Les lasers a base d'Yb3+ possedent beaucoup d'avantages compares aux lasers Nd3+ du fait de leur structure electronique simple et de leur deterioration moins rapide. Parmi les matrices cristallines pouvant accueillir l'ytterbium, les orthosilicates Yb:Y 2SiO5, Yb:Lu2SiO5 et Yb:Sc2SiO 5 se positionnent tres bien, du fait de leur bonne conductivite thermique et du fort eclatement de leur champ cristallin necessaire a l'elaboration de lasers quasi-3 niveaux. De plus l'etude fine et systematique des proprietes microscopiques de nouveaux materiaux s'avere toujours tres interessante du point de vue de la recherche fondamentale, c'est ainsi que de nouveaux modeles sont concus (par exemple pour le champ cristallin) ou que de nouvelles proprietes inhabituelles sont decouvertes, menant a de nouvelles applications. Ainsi d'autres materiaux dopes a l'ytterbium sont connus pour leurs proprietes de couplage electron-phonon, de couplage magnetique, d'emission cooperative ou encore de bistabilite optique, mais ces proprietes n'ont encore jamais ete mises en evidence dans Yb:Y 2SiO5, Yb:Lu2SiO5 et Yb:Sc2SiO 5. Ainsi, cette these a pour but l'etude des proprietes optiques et des interactions microscopiques dans Yb:Y2SiO 5, Yb:Lu2SiO5 et Yb:Sc2SiO5. Nous utilisons principalement les techniques d'absorption IR et de spectroscopie Raman pour determiner les excitations du champ cristallin et les modes de vibration dans le materiau

  8. Etudes on 1/N

    NASA Astrophysics Data System (ADS)

    Starinets, Andrei Olegovich

    A number of problems in string theory and lattice statistical mechanics is studied using the large N approximation, with N being the dimension of the fundamental representation of the underlying symmetry algebra. As the first problem, the absorption of a minimally coupled massless scalar in the gravitational background created by a stack of near-extremal black three-branes is considered. The low-temperature asymptotic expansion and the high-temperature perturbative expansion are obtained. A field-theoretical calculation of the absorption cross section in the brane's world-volume theory is also performed. As an application, the shear viscosity of a strongly coupled Yang-Mills plasma is computed. In the second problem, we study supergravity solutions with two asymptotically Anti de Sitter regions which are conjectured to describe the renormalization group flow of a four-dimensional field theory from a UV fixed point to an interacting IR fixed point. We show that, in the UV (IR) limit, the two-point function of a minimally-coupled scalar field depends only on the UV (IR) region of the metric, asymptotic to AdS5 thus lending a support to the conjecture. In the third problem, monotonicity and other properties of the canonical c-function in some holographic duals of 4-d quantum field theories are investigated. The canonical c-function and its derivatives are related to the 5-d Green's function of the dual supergravity theory. In the fourth problem, we study solutions of the equations (Δ - λ)φ = 0 and (Δ - λ)2φ = 0 on the covering space C AdSd of the d-dimensional Anti de-Sitter space subject to various boundary conditions, and we analyze their connection to the unitary irreducible representations of SO (d - 1, 2). Finally, as the fifth problem, we compute the phase diagram in the N --> ∞ limit for lattice RPN-1, CPN-1 and QPN-1 σ- models with the quartic action, and more generally for mixed isovector/isotensor models. We show that the N = ∞ limit exhibits phase transitions that are forbidden for any finite N. We clarify the origin of these pathologies by examining the exact solution of the one- dimensional model. We conjecture the correct phase diagram for finite N as a function of the spatial dimension d. We also obtain new results concerning the complex zeros of confluent hypergeometric functions.

  9. Synthese, etude structurale et electrochimique des materiaux d'electrode positive d'oxydes mixtes lithium cobalt nickel oxide (0 /= 1) pour les batteries rechargeables au lithium

    NASA Astrophysics Data System (ADS)

    Grincourt, Yves

    Depuis une dizaine d'annees, on observe un interet grandissant pour les batteries rechargeables au lithium de tension superieure a 4 volts. La commercialisation de ces batteries pour l'electronique grand marche tend de plus en plus a supplanter celle des accumulateurs Ni-Cd et Ni-MH, de tension nominate 1,2 V. Ces batteries au lithium font appel a des materiaux d'electrode positive (cathode a la decharge) du type oxydes mixtes de metaux de transition LiMnO 2, LiMn2O4, LiNiO2 ou LiCoO2. Si le compose LiCoO2 est relativement aise a synthetiser, il n'en demeure pas moins que le cobalt reste un metal plus couteux compare au nickel et au manganese. La synthese de LiNiO2, quart a elle, demeure un probleme du point de vue stoechiometrique. Un defaut de lithium (5 a 10% molaire) conduira a des proprietes electrochimiques mediocres de la batterie. Dans cette etude nous nous proposons donc de preparer par voie humide et par voie seche les materiaux d'electrode positive de la famille LiCoyNi1-yO2 aver (0 ≤ y ≤ 1) et d'etudier en detail l'influence du pourcentage de nickel et de cobalt sur les proprietes electrochimiques des oxydes mixtes Li-Ni-Co. Une des caracteristiques est la morphologie plus fine des poudres de materiaux, observes par microscopie electronique a balayage (MEB). Un traitement thermique a plus basse temperature (750°C) que pour LiCoO2 (850°C) ainsi qu'un leger exces de lithium dans la preparation, ont permis d'aboutir a un materiau de stoechiometrie quasi parfaite. Neanmoins, le role de pilfer joue par 2 a 4% de moles de Ni2+ presents sur les sites lithium, permet de conserver intacte la structure hexagonale de la maille entre deux cycles consecutifs. Afin de mieux comprendre l'influence du vieillissement dune demi-pile Li/LiMeO2 (Me = Ni, Co) a temperature ambiante, des etudes electrochimiques et d'impedance spectroscopique ont ete menees en parallele. Le vieillissement de la cellule s'accompagne seulement dune chute de son potentiel due a son auto

  10. Le transfert de connaissances entre les mathematiques et les sciences. Une etude exploratoire aupres d'eleves de 4e secondaire

    NASA Astrophysics Data System (ADS)

    Samson, Ghislain

    2003-06-01

    Au moment ou dans plusieurs pays on travaille a refondre les programmes d'etudes, tant au primaire qu'au secondaire, l'interet pour le transfert renait. Un des concepts fondamentaux en apprentissage consiste en l'habilete a reutiliser de facon consciente et efficace un acquis d'une situation a une autre situation. Cette recherche emane de preoccupations professionnelles au moment ou le chercheur etait enseignant au secondaire. Au cours de ces annees, il lui a ete possible de constater que plusieurs eleves percevaient difficilement les liens presents entre les disciplines mathematiques et scientifiques. Des travaux en psychologie cognitive et plus particulierement selon une perspective du traitement de l'information ont servi de cadre de reference pour evaluer et analyser les capacites de transfert aupres d'eleves de 4e secondaire. Ce cadre de reference permet de formuler le principal objectif qui est de mieux comprendre le processus de transfert chez des eleves en situation de resolution de problemes scientifiques. Cette these s'interesse donc au transfert en tant que phenomene important du processus d'apprentissage au sens de l'integration. La methode de recherche choisie, de nature qualitative, est principalement axee sur l'evaluation de la capacite a transferer des connaissances lors d'une epreuve et d'un entretien. Pour evaluer ce potentiel de transfert, nous avons elabore deux outils: une epreuve en mathematiques et en sciences et un guide d'entretien. Pour la passation de l'epreuve, le chercheur a pu compter sur la collaboration de 130 sujets provenant de deux ecoles. L'entretien complete la prise de donnees avec 13 sujets ayant accepte de poursuivre l'etude. Les donnees recueillies par ces instruments font ensuite l'objet d'une analyse de contenu. En premier lieu, les verbatims de l'epreuve et de l'entretien ont ete transcrits, puis codifies. La correction des reponses fournies pour les problemes resolus s'est faite a partir d'une grille d

  11. Contribution a l'etude de la binarite des etoiles de type Am. I. HD 125273, binaire spectroscopique a raies doubles

    NASA Astrophysics Data System (ADS)

    Ginestet, N.; Carquillat, J.-M.

    1998-06-01

    We present an observing program undertaken at Observatoire de Haute-Provence, for the search and study of spectroscopic binaries among Am stars. HD 125273 was recognized as an Am star some time ago \\cite[(Olsen 1980;]{ols80} \\cite[Abt 1984);]{abt84} observations, carried out with the CORAVEL spectrovelocimeter, show that this star is a double-lined spectroscopic binary; its orbital elements are as follows: P = 7.482664 days; T = 2448665.660 JD; omega_1 = 355.3() deg; e = 0.071; K_1 = 49.82 km/s; K_2 = 51.75 km/s; V_0 = -17.42 km/s; a_1 sini = 5.113 Gm; a_2 sini = 5.311 Gm; M_1 sin(3i) = 0.412 M_sun;; M_2 sin(3i) = 0.396 M_sun. Stroemgren photometry of the star \\cite[(Olsen 1983)]{ols83} permits us to estimate the following mean physical parameters for the components of the binary: T_eff = 7500 K; log g = 3.70; M_v = 1.24; M = 2.1 M_sun;; R = 3.2 R_sun, and to specify the evolutionary status of the system. Assuming the above mass for the components, we found i ~ 35() deg and a ~ 26 R_sun. This system is thus a detached one without possibility of eclipses. It is likely that the two components are Am stars of very close characteristics. The v sini values, determined from the correlation dips given by CORAVEL, are near 11 km/s for both components. We retain for this binary the hypothesis of rotation-revolution synchronism, because it leads to a value of the radius of the stars in agreement both with the above value and the results of a previous study by \\cite[Kitamura & Kondo (1978)]{kit78} of similar, but eclipsing, systems. The ratio of the correlation dip areas indicates a magnitude difference Delta m_v ~ 0.2 mag. As expected in detached systems of main sequence stars, such as Am's, HD 125273 obeys the mass-luminosity law. Etude effectuee a partir d'observations faites a l'Observatoire de Haute-Provence.

  12. Gestion des ressources hydriques adaptee aux changements climatiques pour la production optimale d'hydroelectricite. Etude de cas: Bassin versant de la riviere Manicouagan

    NASA Astrophysics Data System (ADS)

    Haguma, Didier

    Il est dorenavant etabli que les changements climatiques auront des repercussions sur les ressources en eau. La situation est preoccupante pour le secteur de production d'energie hydroelectrique, car l'eau constitue le moteur pour generer cette forme d'energie. Il sera important d'adapter les regles de gestion et/ou les installations des systemes hydriques, afin de minimiser les impacts negatifs et/ou pour capitaliser sur les retombees positives que les changements climatiques pourront apporter. Les travaux de la presente recherche s'interessent au developpement d'une methode de gestion des systemes hydriques qui tient compte des projections climatiques pour mieux anticiper les impacts de l'evolution du climat sur la production d'hydroelectricite et d'etablir des strategies d'adaptation aux changements climatiques. Le domaine d'etude est le bassin versant de la riviere Manicouagan situe dans la partie centrale du Quebec. Une nouvelle approche d'optimisation des ressources hydriques dans le contexte des changements climatiques est proposee. L'approche traite le probleme de la saisonnalite et de la non-stationnarite du climat d'une maniere explicite pour representer l'incertitude rattachee a un ensemble des projections climatiques. Cette approche permet d'integrer les projections climatiques dans le probleme d'optimisation des ressources en eau pour une gestion a long terme des systemes hydriques et de developper des strategies d'adaptation de ces systemes aux changements climatiques. Les resultats montrent que les impacts des changements climatiques sur le regime hydrologique du bassin de la riviere Manicouagan seraient le devancement et l'attenuation de la crue printaniere et l'augmentation du volume annuel d'apports. L'adaptation des regles de gestion du systeme hydrique engendrerait une hausse de la production hydroelectrique. Neanmoins, une perte de la performance des installations existantes du systeme hydrique serait observee a cause de l'augmentation des

  13. Etude du processus de changement vecu par des familles ayant decide d'adopter volontairement des comportements d'attenuation des changements climatiques

    NASA Astrophysics Data System (ADS)

    Leger, Michel T.

    recension des ecrits sur le changement de comportement en environnement. Nous explorons egalement la famille comme systeme fonctionnel de sorte a mieux comprendre ce contexte d'action environnementale qui est, a notre connaissance, peu etudie. Dans le deuxieme article, nous presentons nos resultats de recherche concernant les facteurs d'influence observes ainsi que les competences manifestees au cours du processus d'adoption de nouveaux comportements environnementaux dans trois familles. Enfin, le troisieme article presente les resultats du cas d'une quatrieme famille ou les membres vivent depuis longtemps des modes de vie ecologique. Dans le cadre d'une demarche d'analyse par theorisation ancree, l'etude de ce cas modele nous a permis d'approfondir les categories conceptuelles identifiees dans le deuxieme article de sorte a produire une modelisation de l'integration de comportements environnementaux dans le contexte de la famille. Les conclusions degagees grace a la recension des ecrits nous ont permis d'identifier les elements qui pourraient influencer l'adoption de comportements environnementaux dans des familles. La recension a aussi permis une meilleure comprehension des divers facteurs qui peuvent affecter l'adoption de comportements environnementaux et, enfin, elle a permis de mieux cerner le phenomene de changement de comportement dans le contexte de la famille consideree comme un systeme. En appliquant un processus d'analyse inductif, a partir de nos donnees qualitatives, les resultats de notre etude multi-cas nous ont indique que deux construits conceptuels semblent influencer l'adoption de comportements environnementaux en famille : 1) les valeurs biospheriques communes au sein de la famille et 2) les competences collectivement mises a profit collectivement durant l'essai de nouveaux comportements environnementaux. Notre modelisation du processus de changement dans des familles indique aussi qu'une dynamique familiale collaborative et la presence d'un groupe de

  14. Le changement comme tradition dans la recherche et la formation a la recherche en biotechnologie et en peripherie Etude de cas en sciences de la sante, sciences naturelles et genie

    NASA Astrophysics Data System (ADS)

    Bourque, Claude Julie

    Le champ de la recherche scientifique et de la formation a la recherche est traverse depuis quelques dizaines d'annees par plusieurs courants et discours associes au changement, mais peu de travaux empiriques permettent de comprendre ce qui change concretement. C'est la contribution originale de cette these au champ de l'education, plus specifiquement a l'etude sociologique de l'enseignement superieur ou sont concentrees les activites liees a la triade thematique du programme doctoral dans lequel elle a ete produite : recherche, formation et pratique. L'enquete-terrain a ete realisee en 2009 et 2010 aupres de 808 repondants affilies a 60 etablissements au Quebec et a produit un vaste materiau de nature mixte (donnees quantitatives et qualitatives). Un portrait de la nebuleuse biotechnologique qui touche les secteurs des sciences de la sante, des sciences naturelles et du genie a ete realise. Ce domaine concerne des dizaines de disciplines et se revele de nature transdisciplinaire, mais les pratiques n'y sont pas davantage marquees par le changement que celles d'autres domaines connexes. Les dynamiques sociales ont fait l'objet d'analyses comparatives dans quatre contextes: le choix des programmes, des objets et des methodes, le financement, la diffusion et la planification de la carriere. Les resultats indiquent que les echanges entre les agents traditionnellement situes au coeur des activites de recherche dominent ces dynamiques dans tous les contextes etudies. L'etude des representations au fondement des pratiques a revele l'existence de trois ecoles de pensee qui coexistent dans le champ scientifique: academique, pragmatique et economiste. Ces ecoles permettent de categoriser les agents en fonction des zones de fractures qui marquent leurs oppositions tout en identifiant ce qu'ils ont en commun. Les representations et les pratiques liees a la formation temoignent d'un habitus plutot homogene, alors que les contradictions semblent plus souvent ancrees dans des

  15. Physical and genetic map of 5q31: use of fluorescence in situ hybridization data to identify errors in the CEPH database. Centre d'Etude de Polymorphisme Humain.

    PubMed

    Westbrook, C A; Le Beau, M M; Neuman, W L; Keinanen, M; Yamaoka, L H; Speer, M C; Espinosa, R; Nakamura, Y; Williamson, R; Mullan, M

    1994-01-01

    Chromosome 5, band q31, contains the genes responsible for a number of interesting genetic and malignant diseases, as well as many cloned genes. To prepare a high-resolution map of this region, eight anonymous DNA markers were mapped by combining genetic data derived from linkage analysis, with physical data obtained using two-color fluorescent in situ hybridization (FISH). Probe order was determined by FISH on metaphase cells, supplemented with interphase analysis, while genetic distance and likely order were determined by multipoint linkage analysis using genotype data from Centre d'Etude de Polymorphisme Humain (CEPH) pedigrees. Discrepancies between the genetic and physical maps suggested that there was a high rate of genotyping errors in the CEPH data for these markers, and prompted a statistical analysis to identify these errors. By assuming a known physical order (as determined by FISH) it was possible to identify markers which had the greatest degree of error. The average typing error was estimated at 1.8%, but several markers had much higher error rates; a 14% error rate was predicted for one locus, which was subsequently confirmed by retyping. The analysis led to the preparation of a revised map spanning 24.5 cM of 5q31. This study illustrates the power of FISH to determine physical order over a wide genomic distance, and demonstrates how order can be used as an adjunct to linkage analysis, particularly in the identification of genotyping errors.

  16. Phoneme, Grapheme, Onset-Rime and Word Analysis in Braille with Young Children

    ERIC Educational Resources Information Center

    Crawford, Shauna; Elliott, Robert T.; Hoekman, Katherine

    2006-01-01

    Two groups of sighted pre-school children were taught to name six braille letters: one group received phoneme instruction and the other grapheme instruction. Ten boys and ten girls (average age 4:5 years) participated. There was a statistically significant advantage for the phoneme group (Experiment 1). In a repeated measures design, 16 sighted…

  17. Computer Modeling of Time-Dependent Rime Icing in the Atmosphere,

    DTIC Science & Technology

    1983-01-01

    IDGTIER, NCOU.NCOUI ,NCOL.LJJ 435 C 436 COMMON ALPHAR.PI/AEROI/XE.YE/AER03/NCOUNCOL/ AERO2 /XC.YC.R.O.SI.CO 437 C 438 10 FORMAT(’OFOR EON. SOLN. IER=’.I3...XZI .YZI.F.N.NCOU.NCOLL, II 539 C 540 COMMON ALPHAR.PID/AERDI/XE,YE/AERO3/NCOU.NCOL/ AERO2 /XCYC.GAMMA.D 541 .Si.CO 542 ./GRID/XMIN.XMAX.YMIN.YMAX.XZ...COMMON ALPHAR.PI/AERO3/NCOU.NCOL/ AERO2 /XC.YC.GAMMA.D.SI.CO 2608 ./AIR/XP.YP.DELPSI ,TYPE 2609 C 2610 C IN X= 2611 C IN Y=COORDS. AT WHICH AIR VELOCITY

  18. RIME: The Recoverable Item Management Evaluator. Volume II. Section I. Events Generator Programs.

    DTIC Science & Technology

    1980-05-01

    NKAXPEL 0 0 P 6 STOP S2 VRITI(6,13)"RZAD END-Of-rILE 00 C76 STOP NUW," ~~2 21 ~ VtTI(6,14)"!LI.ST UJ-RU~ Vkt )SM1 22 STOP -. 7 MEMORY EXPANDBD: USE...reparable generations (LDRGNT). If so, LDCONT is reset to LDRGNT. Next, similar calculations are performed for each SRU. Finally, the routine checks If the...of the above cases, appropriate counters of SRU events are reset after each of the Monte Carlo calculations to ensure that the correct probability

  19. Use of low-temperature scanning electron microscopy to observe icicles, ice fabric, rime and frost

    SciTech Connect

    Wergin, W.P.; Rango, A.; Erbe, E.F.

    1996-12-31

    Previous studies showed that low temperature scanning electron microscopy (SEM) can be used to record images of precipitated snow crystals, which collectively form structures that are commonly known as snowflakes. Information about the structure of snow crystals can be used to improve models that estimate the water equivalent of the winter snowpack. These models, which are based on satellite microwave data, have practical use in approximating the quantity of water that will be available for crop irrigation and hydroelectric power. Our previous success of using low temperature SEM to image snow crystals has encouraged us to utilize this technique for other types of frozen aqueous specimens.

  20. Phonemic Segmentation, Not Onset-Rime Segmentation, Predicts Early Reading and Spelling Skills.

    ERIC Educational Resources Information Center

    Nation, Kate; Hulme, Charles

    1997-01-01

    Gives children (ages 5+ to 9+) four tests of phonological skill to investigate relationships between these measures and their predictive relationship with reading and spelling ability. Finds performance at phonemic segmentation, rhyme sound categorization, and alliteration sound categorization improved with age, but all groups performed onset-rime…

  1. Optical properties of urban aerosol from airborne and ground-based in situ measurements performed during the Etude et Simulation de la Qualité de l'air en Ile de France (ESQUIF) program

    NASA Astrophysics Data System (ADS)

    Chazette, Patrick; Randriamiarisoa, Hariliva; Sanak, Joseph; Couvert, Pierre; Flamant, Cyrille

    2005-01-01

    Urban aerosol microphysical and optical properties were investigated over the Paris area coupling, for the first time, with dedicated airborne in situ instruments (nephelometer and particle sizers) and active remote sensor (lidar) as well as ground-based in situ instrumentation. The experiment, covering two representative pollution events, was conducted in the framework of the Etude et Simulation de la Qualité de l'air en Ile de France (ESQUIF) program. Pollution plumes were observed under local northerly and southerly synoptic wind conditions on 19 and 31 July 2000, respectively. The 19 July (31 July) event was characterized by north-northwesterly (westerly) advection of polluted (clean) air masses originating from Great Britain (the Atlantic Ocean). The aerosol number size distribution appeared to be composed mainly of two modes in the planetary boundary layer (accumulation and nucleation) and three modes in the surface layer (accumulation, nucleation, and coarse). The characteristics of the size distribution (modal radii and geometric dispersion) were remarkably similar on both days and very coherent with the aerosol optical parameters retrieved from lidar and nephelometer measurements. The city of Paris mainly produces aerosols in the nucleation mode (modal radius of ˜0.03 μm) that have little influence on the aerosol optical properties in the visible spectral range. The latter are largely dominated by the scattering properties of aerosols in the accumulation mode (modal radius of ˜0.12 μm). When the incoming air mass is already polluted (clear), the aerosol in the accumulation mode is shown to be essentially hydrophobic (hydrophilic) in the outgoing air mass.

  2. Etude du mecanisme de predissociation de l'ion moleculaire de protoxyde d'azote par la mesure de l'energie cinetique des fragments de l'oxyde nitrique et de l'oxygene

    NASA Astrophysics Data System (ADS)

    Delisle, Claude

    La reaction N2 + O+ ↔ NO + + N, laquelle joue un role important dans la physique de la haute atmosphere, a ete le sujet de plusieurs etudes. Bien que cette reaction ait ete l'objet d'une quantite importante de travaux, ces derniers ne permettent toutefois pas de comprendre entierement le mecanisme d'un point de vue quantique, particulierement les niveaux d'energie excites des fragments qui permettent cette reaction. Puisque cette reaction n'est pas tres facile a reproduire en laboratoire, nous avons utilise la spectroscopie laser sur faisceaux d'ions rapides afin d'explorer les limites de dissociation de l'ion moleculaire intermediaire de cette reaction, a savoir l'ion N2O+. Le faisceau d'ions N2O+ rapides, apres excitation de l'ion moleculaire vers un niveau predissocie de l'etat A2Sigma+, se dissocie pour produire les fragments ioniques O+ et NO+. Par la mesure de la variation du nombre de fragments ioniques en fonction de l'energie cinetique des ions N2O+, nous avons enregistre les spectres de predissociation de l'ion N2O+. Lorsque c'etait possible, nous avons procede a l'analyse de ces spectres de dissociation afin d'en tirer les constantes moleculaires. Pour certaines des transitions rotationnelles intenses, nous avons mesure l'energie cinetique acquise par les fragments lors de la predissociation de l'ion N 2O+. Afin d'analyser les distributions en energie cinetique, nous avons developpe une simulation de l'experience en considerant, entre autres choses, la position des niveaux de vibration et de rotation des fragments diatomiques de chacune des limites de dissociation de N2O+. Les resultats de l'analyse sont exprimes en termes de population des niveaux de vibration des fragments diatomiques pour une distribution donnee de la population des niveaux de rotation des fragments. Les resultats ainsi obtenus, montrent que les fragments diatomiques sont produits dans des niveaux de vibration fortement excites. De tels niveaux d'excitation ne correspondent pas aux

  3. Education relative a l'environnement (ERE): Une etude des representations sociales et des pratiques educatives d'enseignants de science et technologie du secondaire en contexte de formation continue

    NASA Astrophysics Data System (ADS)

    Collard-Fortin, Ugo

    Le developpement des sciences/technologie a tres clairement contribue a ce que ce dernier domaine de savoirs jouisse d'une place de choix au sein de notre societe. Au-dela des progres de notre civilisation inherents a ce dernier developpement, cette croissance amena avec elle un lot d'ineluctables dommages collateraux, contribuant en corollaire a l'emergence de diverses problematiques environnementales inquietantes pour lesquelles les valeurs ainsi que le mode de fonctionnement de la societe occidentale contemporaine sont largement tributaires. C'est entre autres en reponse a cet etat de fait que la recente vague de reforme de l'Education conduisit a l'integration, dans les curricula de sciences/technologie, de contenus relavant d'education relative a l'environnement (ERE). Face au changement, les enseignants de sciences ont du s'approprier ce nouveau programme afm de l'enseigner a leurs eleves. Toutefois, l'analyse de la situation montre que les prescriptions du programme en matiere d'ERE ne se sont pas toujours traduites en de reelles actions dans la pratique. Le contexte de notre etude s'est interesse aux pratiques educatives de l'ERE ainsi qu'a la representation sociale qui en decoule. Notre recherche aborde plus specifiquement la problematique de la modification de ces derniers objets chez les enseignants de sciences et technologie du deuxieme cycle du secondaire. Pour y arriver, nous avons propose a un groupe de trois praticiens de participer a une activite, en communaute de pratique, de formation continue orientee autour de thematiques ERE. Cette recherche developpement, s'inscrivant dans un paradigme qualitatif/interpretatif, s'est appuyee sur une cueillette de donnees effectuee a partir d'entrevues semi-dirigees, d'observations en situation et d'un groupe de discussion, au debut et a la fm de la formation continue. Les donnees brutes ont ete soumises a une demarche d'analyse inductive et ont genere diverses categories etayant nos objets de recherche

  4. Measurement of x-ray laser beam divergence with CADIX, a time-resolved diagnostic tool using an insertable multilayer mirror

    NASA Astrophysics Data System (ADS)

    Reverdin, C.; Bourgade, J. L.; Bruneau, J.; Charret, M.; Desenne, D.; Dulieu, A.; Dumont, H.; Louis-Jacquet, M.; Sauneuf, R.; Schirmann, D.; Troussel, P.

    1992-10-01

    To study the x-ray laser beam deflection and divergence due to the refraction within the plasma, a specific diagnostic called CADIX has been developed at the Centre d'Etudes de Limeil-Valenton (CEL-V). When the beam refraction analysis is required a multilayer mirror is inserted on the x-ray laser output beam. It selects the lasing wavelengths and reflects them to an off-axis streak camera which records x rays as a function of time and angle. A detailed description of the instrument is presented including multilayer mirror calibration at the LURE (Laboratoire pour L'Utilisation du Rayonnement Synchrotron, Orsay, France). An experimental measurement on neon-like silver amplification is presented and analyzed with the response of the mirror. An important refraction effect is observed.

  5. MONOX: un nouveau spectrogoniomètre pour le rayonnement X mou et X-UV

    NASA Astrophysics Data System (ADS)

    André, J.-M.; Avila, A.; Barchewitz, R.; Benbalagh, R.; Delaunay, R.; Druart, D.; Fontaine, M.-F.; Ringuenet, H.

    2004-11-01

    Un spectrogoniomètre de laboratoire utilisant comme source un tube émettant des radiations caractéristiques dans le domaine X mou et X-UV a été développé au Laboratoire de Chimie Physique (CNRS/UPMC) dans le cadre de l'Action Coordonnée Optique du CNRS. L'appareil comprend un monochromateur de type “double-cristaux" équipé de miroirs multicouches ou de cristaux de grande période et un goniomètre θ-2θ . Il permet des mesures de pouvoir réflecteur et de diffusion de dispositifs optiques, en particulier de miroirs et réseaux multicouches. Dans un futur proche il sera aussi destiné à la caractérisation de nouvelles sources et de détecteurs X-UV. L'appareil peut aussi être utilisé comme spectromètre à cristal plan si l'anode est remplacée par l'échantillon à analyser. Différents exemples des possibilités offertes par cet instrument opérant en mode “réflectométrie" ou en mode “spectrométrie" sont présentés.

  6. Quality of life assessment in Hodgkin's disease: a new comprehensive approach. First experiences from the EORTC/GELA and GHSG trials. EORTC Lymphoma Cooperative Group. Groupe D'Etude des Lymphomes de L'Adulte and German Hodgkin Study Group.

    PubMed

    Flechtner, H; Rüffer, J U; Henry-Amar, M; Mellink, W A; Sieber, M; Fermé, C; Eghbali, H; Josting, A; Diehl, V

    1998-01-01

    Previous reports from available trials have dealt with negative long-term sequelae in Hodgkin's disease (HD) survivors. There is, however, a lack of longitudinal data showing the correlation between outcome and various treatment-related variables and the process of re-adaptation into normal life after the end of treatment. In order to investigate the quality of life (QoL) of patients with HD in different dimensions during active treatment and follow-up and to identify longitudinal patterns of QoL dimensions during re-adaptation to normal life within the EORTC Lymphoma Cooperative Group and Groupe D'Etude des Lymphomes de L'Adulte (EORTC/GELA) and the German Hodgkin Study Group (GHSG), QoL assessment strategies were put into use over the last three to five years. Furthermore, the efforts aimed at obtaining cross-cultural comparisons between the participating countries and study groups (EORTC/GELA and GHSG). Within the randomised EORTC/GELA Trial 'H8' for clinical stage I-II HD which started in September 1993, patients receive a QoL questionnaire for completion at each follow-up visit during the first 10 years after the end of active therapy. The corresponding 'HD8' study of the GHSG employs the assessment of QoL during and after active treatment periods. Within both studies, the EORTC QLQ C30 is used for QoL assessment incorporated in the QLQ-S (quality of life questionnaire for survivors), which additionally addresses the aspects of fatigue/malaise, sexuality, specific side effects, and retrospective evaluation of treatment. In total the QLQ-S includes 45 questions on 14 functional, symptom, and fatigue scales, 15 additional single items, and 3 open questions. In addition to the longitudinal QoL assessment, the GHSG carried out cross-sectional QoL trials with all cured surviving patients from the past HD1-6 studies and a matched normal control sample employing the QLQ-S and the life situation questionnaire (LSQ), an instrument covering objective data from 45

  7. HBA1c: clinical and biological agreement for standardization of assay methods. Report by the experts of ALFEDIAM (Association de Langue Française pour lEtude du Diabète et des Maladies Métabolique) and SFBC (Société Française de Biologie Clinique).

    PubMed

    Gillery, P; Bordas-Fonfrède, M; Chapelle, J P; Drouin, P; Hue, G; Lévy-Marchal, C; Périer, C; Sélam, J L; Slama, G; Thivolet, C; Vialettes, B

    1999-09-01

    Glycohaemoglobin, and particularly haemoglobin A1c(HbA1c), assays have been used for many years to retrospectively evaluate the glycaemic control of diabetic patients. Cut-off values have been established for deciding treatment modifications. The techniques used in the laboratories however exhibit varying quality, and all of them are not yet standardized. The consequence is an under-utilization of this test, especially in non-hospital practice. In this context, working groups of Société Française de Biologie Clinique (SFBC), Association de Langue Française pour l'Etude du Diabète et des Maladies Métaboliques (ALFEDIAM) and Société Française d'Endocrinologie (SFE) have met together, in order to analyze the national status, and to propose practical recommendations for implementing a standardization process on the basis of international experiences. It is recommended to exclusively express results as HbA1c percentage, using methods standardized and certified by comparison to reference methods such as those using Diabetes Control and Complications Trial (DCCT) values. Simultaneously, contacts have been established with manufacturers, and the realisation of periodic quality control surveys was encouraged.

  8. Predicting Growth of Nonword Reading and Letter-Sound Knowledge Following Rime- And Phoneme-Based Teaching

    ERIC Educational Resources Information Center

    Savage, Robert; Carless, Sue

    2004-01-01

    The present study sought to extend a recent study by Savage, Carless and Stuart, by looking at the pre-test phonological skills that predicted improvements in letter-sound knowledge and nonword reading. Results showed overall that phoneme manipulation predicted improvements in nonword reading and letter-sound knowledge even when pre-test scores on…

  9. Étude structurale par rayonnement synchrotron de superréseaux d'oxydes pérovskites

    NASA Astrophysics Data System (ADS)

    Nemoz, M.; Dooryhee, E.; Hodeau, J.-L.; Dubourdieu, C.

    2004-11-01

    Perovskite oxides are analyzed by using high resolution synchrotron radiation diffraction. The diffraction profiles are fitted, taking into account the structural and chemical disorders which depart from the ideal defect-free superlattice. Two types of superlattices, (BaTiO{3}/SrTiO{3}){15} and (La{0.7}Sr{0.3}MnO{3}/SrTiO{3}){15}, are synthesized by metal-organic chemical vapor deposition (MOCVD) on <{001}> oriented Nb-doped SrTiO{3} substrates. High-angle diffraction data show the excellent crystallinity and epitaxy of the films. For the (BaTiO{3}/SrTiO{3}){n} multilayers we observe a pseudo tetragonal symmetry with no difference between a and b axes, and they present a significant strontium/baryum interdiffusion. The (La{0.7}Sr{0.3}MnO{3}/SrTiO{3})n multilayers and their substrates almost have the same a=b parameter. Along the c axis, La{0.7}Sr{0.3}MnO{3} and SrTiO{3} have different lattice parameters. The crystallographic coherence of the stacking is higher in these samples.

  10. Black Hole Event Horizons and Advection-Dominated Accretion

    NASA Technical Reports Server (NTRS)

    McClintock, Jeffrey; Mushotzky, Richard F. (Technical Monitor)

    2002-01-01

    The work supported in part by this grant is part of a larger program on the detection of black hole event horizons, which is also partially supported by NASA grant GO0-1105A. This work has been carried out primarily in collaboration with Dr. M. Garcia and Prof. R. Narayan at the Harvard-Smithsonian Center for Astrophysics and with D. Barret and J. Hameury at Centre d'Etude Spoliate des Rayonnements, France. Our purpose is to confirm the existence of black-hole event horizons by comparing accreting black holes to secreting neutron stars in quiescent X-ray novae. Such a comparison is feasible because black holes and neutron stars are both present in similar environments in X-ray novae. Our second purpose is to assess the nature of accretion flows onto black holes at very low mass transfer rates. Observations of some XMM targets are still pending, whereas most of the Chandra observations have been completed. We anticipate further publications on this work in the future.

  11. Search for Heavy Top-like Quarks t-rime ---> Wq Using Lepton Plus Jets Events in 1.96-TeV p anti-p Collisions

    SciTech Connect

    Lister, Alison; /UC, Davis

    2008-10-01

    We present the results of a search for a new heavy top-like quark, tprime, decaying to a W boson and another quark using the CDF II Detector in Run II of the Tevatron ppbar collider. New top-like quarks are predicted in a number of models of new physics. Using a data sample corresponding to 2.8 fb-1 of integrated luminosity we fit the observed spectrum of total transverse energy and reconstructed quark mass to a combination of background plus signal. We see no evidence for tprime production, so use this result to set limits on the tprime tprimebar production cross section times the branching ratio of tprime to Wq and infer a lower limit of 311 GeV/c2 on the mass of the tprime at 95% CL.

  12. Large Grain Instruction and Phonological Awareness Skill Influence Rime Sensitivity, Processing Speed, and Early Decoding Skill in Adult L2 Learners

    ERIC Educational Resources Information Center

    Brennan, Christine; Booth, James R.

    2015-01-01

    Linguistic knowledge, cognitive ability, and instruction influence how adults acquire a second orthography yet it remains unclear how different forms of instruction influence grain size sensitivity and subsequent decoding skill and speed. Thirty-seven monolingual, literate English-speaking adults were trained on a novel artificial orthography…

  13. The Enigma of the Origin of Round, Deep, Rimed Lakes in the Russian Heartland-Was Lake Smerdyachie Formed During the Impact of an Extraterrestrial Body?

    NASA Astrophysics Data System (ADS)

    Abbott, D. H.; Gusiakov, V. K.; Kiselev, A.; Amelin, I. I.; Breger, D. L.; McCafferty, P.

    2014-12-01

    The heartland of Russia has many enigmatic deep lakes. Shallow lakes have a more obvious origin, perhaps as kettle lakes, oxbow lakes or subsidence features. Deep lakes, particularly round lakes with partial or complete rims are more problematic. Traditionally, round or nearly round lakes with rims are candidates for Holocene age impact structures. The problem is that there are too many such lakes in the Russian heartland- a minimum of 15 deep, round lakes with diameters between 0.2 and 3 km. Even with a possibly increased impact rate during the Holocene, these deep lakes would represent the entire budget of Holocene impacts concentrated in one small region of the Earth. We examine here Lake Smerdyachie, a previously proposed impact lake. Smerdyachie is perfectly round with a raised rim. It has a diameter of about 350 meters and a maximum water depth of over 30 m. The basement at Smerdyachie is at~40 meters depth. It consists of Carboniferous age carbonate rock with fossils of brachiopods, crinoids and gastropods. The overlying material consists of unconsolidated, sand and silt-sized, quartz-rich sediments. We found clasts of brachiopod, crinoid and gastropod-bearing Carboniferous carbonate rock up to 32 cm in diameter on the SE rim of Smerdyachie. These clasts are present over about 1/3 of the total circumference of the lake. We also made panned concentrates of the sediment on the rim. To the NW, the concentrated sediment has a negative magnetic susceptibility (-0.07 to -0.03 cgs units), consistent with a higher concentration of pulverized limestone. To the SE, the sediment has a positive magnetic susceptibility (0.06 to 0.35 cgs units). The areas of positive magnetic susceptibility lie on the SE two-thirds of the rim of the lake. The highest susceptibility value is from the sample taken closest to the lake shoreline on the SE rim. This spatial distribution of susceptibility could mean that there is a higher concentration of iron rich material on the SE side of the lake. To test this hypothesis, we plan to remove the calcium carbonate from our previously measured samples and then to remeasure their magnetic susceptibility. We will then examine the material with the highest magnetic susceptibility for possible impactor fragments.

  14. Recombinative Generalization of Subword Units Using Matching to Sample

    ERIC Educational Resources Information Center

    Mahon, Catherine; Lyddy, Fiona; Barnes-Holmes, Dermot

    2010-01-01

    The purpose of the current study was to develop and test a computerized matching-to-sample (MTS) protocol to facilitate recombinative generalization of subword units (onsets and rimes) and recognition of novel onset-rime and onset-rime-rime words. In addition, we sought to isolate the key training components necessary for recombinative…

  15. Orthographic Analogies and Early Reading: Explorations of Performance and Variation in Two Transfer Tasks.

    ERIC Educational Resources Information Center

    Savage, Robert; Stuart, Morag

    2001-01-01

    Investigates the use of orthographic analogies in 6-year-olds. Notes that neither rime nor phoneme awareness measures were correlated with rime inference uses and that vowel, but not rime inference, was correlated with scaffolding errors. Finds that rime detection was the strongest predictor of reading ability, whereas phoneme segmentation was the…

  16. Etude par spectroscopie raman du chlorhydrate de cocaine.

    PubMed

    Gamot, A P; Vergoten, G; Fleury, G

    1985-05-01

    Raman spectra of cocaine hydrochloride in the polycrystalline state and in saturated aqueous solutions have been recorded at room temperature from 0 to 4000 cm(-1) and at 9 K from 0 to 200 cm(-1) (only for the polycrystalline state). They show that cocaine can be characterized by the following proposed assignments. For the tropane nucleus the frequencies 851 and 786 cm(-1) (piperidine) and 896, 870 cm(-1) (pyrrolidine); these frequencies are assigned to ring carbon stretching vibrations V(C-C) Bands for the ester functional groups can be observed at 1713 cm(-1) (v(CO)) and 1203 cm(-1) (v((C-O-O)). The benzene nucleus is also important in characterization of cocaine hydrochloride because of its bands at 616, 990, 1000, 1026 and 1596 cm(-1). Special reference is made first to the work in the low-frequency range at room temperature and 9 K and secondly to the polarization studies of saturated aqueous solutions in the range 700-1726 cm(-1). The results constitute a pool of analytical characteristics which can be used for toxicological investigations, and also show all the possibilities of Raman spectroscopy in this field.

  17. Etude du champ magnetique dans les nuages moleculaires

    NASA Astrophysics Data System (ADS)

    Houde, Martin

    2001-12-01

    Ce travail est une étude du champ magnétique duns l'environnement circumstellaire des étoiles jeunes. Il a pour origine la certitude qu'avait l'auteur qu'il se devait d'être possible de détecter la présence d'un champ magnétique, et de possiblement le caractériser, par le biais d'observations de profils spectraux d'espèces moléculaires ioniques. Il en découle donc qu'un des buts principaux était de prouver que cela est effectivement possible. La thèse comporte alors des éléments théoriques et expérimentaux qui sont à la fois complémentaires et intimement liés. L'aspect théorique est basé sur l'interaction mutuelle que des particules neutres et chargées peuvent avoir l'une sur l'autre daps un plasma faiblement ionisé comme ceux existants daps les nuages moléculaires sites de formation stellaire. Il appert que la présence d'un champ magnétique a un effet direct sur le comportement des ions (via la force de Lorentz) et indirect sur les molécules neutres (via les nombreuses collisions entre les deux types de particules). Une telle interaction est, comme il est maintenant bien connu, présente dans les premières étapes de la formation dune étoile. Il s'agit bien sûr de la diffusion ambipolaire. Nous montrerons qu'il existe cependant un autre type de diffusion, jusqu'ici inconnue, qui se manifeste plus tard au tours de l'évolution des nuages moléculaires. Celle-ci peut avoir un effet dramatique sur l'apparence des profils spectraux (de rotation moléculaire) des espèces ioniques lorsque comparés à ceux qu'exhibent des espèces neutres coexistantes. Mais pour ce faire, il doit y avoir existence de mouvements organisés (des flots ou jets) de matière ou encore la présence de turbulence dans les régions considérées. Une distribution de vélocité du type maxwellienne ne révèlera pas la présence du champ magnétique. Les observations, qui ont pour but de confirmer la théorie, se situent dans le domaine des longueurs d'ondes millimétriques et sous- millimétriques. Plusieurs espèces moléculaires furent détectées dans un échantillon significatif de nuages moléculaires. L'effet prédit fut confirmé et ce peu importe si les raies observées sont opaques ou transparentes. Dans le dernier chapitre, nous considérerons une application intéressante où nous utiliserons la manifestation de cet effet (ou son manque) pour vérifier l'alignement préférentiel des flots bipolaires, qui accompagnent souvent la présence de proto- étoiles, avec le champ magnétique local.

  18. Etude de la resistance en fatigue des materiaux bitumineux

    NASA Astrophysics Data System (ADS)

    Touhara, Radouen

    The goal of this research program is to evaluate and characterize the fatigue behaviour of two GB20 hot mix asphalt made with two different bitumen. One of them is made in laboratory with a straight-run PG58-28 bitumen, while the second mix was made in an asphalt plant with a PG64-28 bitumen. Two characterization tests, in homogeneous conditions, done in traction/compression on cylindrical specimens are used in this study. First, a complex modulus test performed in the linear viscoelasticity (LVE) domain is used to characterize the mixes and second, a fatigue test is done to evaluate the mixes performances. The fatigue tests were done in strain controlled at different amplitude. All fatigue tests were performed at 10Hz, but at different temperatures (10, 20 and 30°C) in order to evaluate the effect of the temperature on the fatigue behaviour of those mixes. In this document, the results are presented, and the analysis of the results as a function of the grade of bitumen, the tests’ temperature and the dispersion of the results is performed. Also, the DGCB method is applied to the fatigue results to calculate the rate of damage per cycle followed by a study of the different failure criteria (Nf) to predict the fatigue life of asphalt mixes. Keywords: bituminous materials, fatigue, complex modulus, Damage.

  19. Systeme complet d'interferometrie radar: Etude de cas

    NASA Astrophysics Data System (ADS)

    Vincent, Frederic

    2002-09-01

    La recherche realisee a porte sur la mise au point de plusieurs ameliorations dans la chaine de traitement interferometrique necessaire pour pouvoir appliquer l'interferometrie radar (InROS) a des problemes d'interets majeurs au Quebec. Ainsi, la mesure de la deformation du sol et la creation de modeles numeriques d'altitude (MNA) par InROS en zone de coherences variables ont ete explorees au cours de cette recherche. Les faibles taux de deformation et les petites dimensions spatiales des zones affectees, les rapides variations des conditions climatiques et la presence de vegetation dense sont les principaux facteurs responsables de l'echec de l'InROS pour la mesure des deformations de glissements de terrain au Quebec. L'InROS s'est par contre averee etre un outil puissant pour le suivi des mouvements de glace sur les cours d'eau nordiques pour la securite des populations riveraines et pour la navigation fluviale. Une methode de fusion de MNA InROS de differentes configurations de prises de vue d'images en fonction des caracteristiques locales de pente et de coherence a ete developpee afin d'ameliorer la qualite des MNA InROS en zone de fortes variations de coherence. Finalement, une methode de correction des effets atmospheriques qui affectent les interferogrammes, basee sur l'acquisition simultanee de donnees GPS et de donnees radar, a aussi ete developpee au cours de cette recherche.

  20. Etude thermo-aeraulique d'une piscine interieure

    NASA Astrophysics Data System (ADS)

    Guerfala, Nasreddine

    Les grands espaces fermés (amphithéâtres, supermarchés, gymnases et piscines) jouent un rôle essentiel dans l'économie et la société canadienne mais n'assurent pas nécessairement le confort thermique et la bonne qualité de l'air intérieur. En outre, leur consommation énergétique demeure très élevée. Plus spécifiquement, les piscines intérieures présentent certaines particularités telles qu'une humidité relative élevée, une température contrôlée de l'eau et une condensation possible sur les parois ce qui rend la tâche d'assurer le confort des baigneurs encore plus difficile. Rares sont les études réalisées pour ce type de bâtiment malgré l'existence de pistes d'optimisation de la consommation énergétique et l'amélioration de la qualité d'air intérieur. Dans cette optique, ce mémoire présente une étude thermo-aéraulique réalisée sur la piscine intérieure de l'Université Bishop's (Sherbrooke, Canada). La simulation numérique a été effectuée en utilisant le logiciel TRNSYS. L'approche adoptée pour la modélisation est la méthode zonale qui découpe l'espace de travail étudié en plusieurs zones fictives tout en calculant les caractéristiques thermo-aérauliques (température, pression, nombre de changement d'air par heure). D'autre part, une validation expérimentale en situations réelles est mise en œuvre au sein de cette piscine moyennant un dispositif expérimental spécifique. Ce dernier a été conçu spécialement pour s'adapter aux caractéristiques du milieu (hauteur du bâtiment, présence de l'eau et forte humidité) afin de mesurer la température, la pression et la vitesse de l'air dans plusieurs endroits significatifs de la piscine. Cette étude développe un outil de calcul capable de prédire les températures de différentes zones thermiques et des surfaces de l'enveloppe du bâtiment d'une part et de calculer le débit massique de l'air entre les zones ainsi que le nombre de changement d'air par heure pour en déduire le confort thermique des occupants d'autre part. De plus, elle fournit une base de données des mesures extensives de température, humidité relative et de vitesse de l'air prises à l'été 2012 qui ont permis de valider les simulations numériques réalisées. Enfin, une étude paramétrique a été menée pour savoir l'effet de la modification de certains paramètres tel que les caractéristiques des systèmes de ventilation et chauffage sur la consommation énergétique du bâtiment et le confort thermique des occupants. Par conséquent, des recommandations ont été proposées. Les résultats ainsi obtenus permettront aux industriels d'améliorer les performances énergétiques des piscines intérieures et donneront des solutions constructives pour les concepteurs de ce type de bâtiment. Mots clés : Grands espaces fermés, piscine intérieure, méthode zonale, confort thermique, qaulité d'air intérieur, efficacité énergétique.

  1. Etude des effets du martelage repetitif sur les contraintes residuelles

    NASA Astrophysics Data System (ADS)

    Hacini, Lyes

    L'assemblage par soudage peut engendrer des contraintes residuelles. Ces contraintes provoquent des fissurations prematurees et un raccourcissement de la duree de vie des composants. Dans ce contexte, le martelage robotise est utilise pour relaxer ces contraintes residuelles. Trois volets sont presentes: le premier est l'evaluation des effets des impacts unitaires repetes sur le champ de contraintes developpe dans des plaques d'acier inoxydable austenitique 304L vierges ou contenant des contraintes residuelles initiales. Dans la deuxieme partie de ce projet, le martelage est applique grace au robot SCOMPI. Les contraintes residuelles induites et relaxees par martelage sont ensuite mesurees par la methode des contours, qui a ete adaptee a cet effet. Dans la troisieme partie, le martelage est modelise par la methode des elements finis. Un modele axisymetrique developpe grace au logiciel ANSYS permet de simuler des impacts repetes d'un marteau elastique sur une plaque ayant un comportement elastoplastique.

  2. Mathematics Comparison Study = Etude Comporative Portant Sur les Mathematiques.

    ERIC Educational Resources Information Center

    Alberta Dept. of Education, Edmonton. Curriculum Standards Branch.

    At the request of the Council of Ministries of Education, Canada (CMEC), Alberta Learning conducted this Mathematics Comparison Study. The focus of this study is from Kindergarten to Grade 12. All provinces and territories were invited to participate, and only the Quebec region declined. Participating regions were invited to send a representative…

  3. Equivalents dynamiques pour l'etude de la stabilite transitoire

    NASA Astrophysics Data System (ADS)

    El Aouni, Wassil

    Today's transient stability (TS) studies are a necessary tool to predict power systems behavior after the occurring of huge faults (ex: short-circuit, generator's lost, etc.). These studies allow us to plan the necessary actions to take in order to maintain the required levels of availability and quality of the electricity production. However, because of the fast increase of the size and the complexity of the power systems, these (TS) studies require higher duration and efforts for their calculations to be processed. The problem of this thesis is therefore: How to reduce the (TS) programs duration and calculation efforts while keeping the precision of their results? In order to resolve this problem, an initial literature review was performed. This literature review allowed us to notice that power systems reduction techniques used to decrease duration of (TS) simulation programs were designed long time ago. These techniques have the common goal of reducing the (TS) simulation duration and effort while keeping the same original power system dynamic behavior. This literature review leaded us also to choose a four steps power system reduction method: In the first step, the power system internal and external zones are chosen. In the second step the power system external zone generators able to be aggregated together are identified using the slow coherency method in addition to a time domain (TS) simulation. In the third step, dynamic parameters of the equivalent reduced network machines are derived using the structure preserving method which has the advantage of being useful for both classical and detailed power systems models. In the fourth step, the equivalent power system admittance matrix is processed using Zhukov method. The method proposed to resolve the problem of this thesis was afterwards implemented under Matlab(c) functions format. These aggregation functions were validated in the case of (TS) and (SIME) programs for the two following test network: " New England " 10 machines 39 buses under classical and detailed models, and the IEEE 50 machines 145 buses under classical model. PSSE(c) industrial software was also used in order to validate the results. The designed aggregation functions allowed us to have a significant increase of the speed of the (TS) and (SIME) programs while keeping a good accuracy of their outputs.

  4. Etude RICH Nursing. Plus de connaissances et de preuves scientifiques

    PubMed Central

    SCHUBERT, MARIA

    2009-01-01

    L’importance et la validité des résultats de l’étude RICH-Nursing* ont été récemment mises en cause par certains milieux, ce qui a provoqué certaines incertitudes chez les infirmières. Les auteurs reviennent sur l’impact actuel de cette étude et évoquent les perspectives d’avenir. PMID:25221376

  5. Potentialités des lasers à fibre dans la génération de rayonnement cohérent UV

    NASA Astrophysics Data System (ADS)

    Martel, G.; Hideur, A.; Ortaç, B.; Lecourt, J.-B.; Chédot, C.; Brunel, M.; Chéron, B.; Limpert, J.; Tunnermann, T.; Grelu, Ph.; Gicquel-Guézo, M.; Labbé, C.; Loualiche, S.; Roussignol, Ph.; Sanchez, F.; Leblond, H.

    2006-12-01

    Le premier laser à fibre dopé aux ions de terres rares fonctionna au tout début des années 60. Il fournissait quelques milliwatts autour de 1 μm. Les décades suivantes virent très peu d'améliorations tant du côté des laboratoires que du point de vue industriel. La dernière décennie (1995/2005) vit se concrétiser la seconde révolution des lasers à fibres. Déjà kilowatt en continu, ils atteignent désormais les 1013 watts/cm2 avec des impulsions de la centaine de femtoseconde. Lors de cette présentation nous passerons en revue les potentialités des lasers à fibre. Nous décrirons les verrous technologiques qui ont été levés ces dix dernières années pour les régimes CW mais aussi femtosecondes. Nous montrerons également comment la prochaine génération de fibres optiques actuellement en développement permettra d'offrir des sources stables et de très haute puissance pour l'avenir proche.

  6. Etude des proprietes microstructurales et rheologiques de suspensions non-aqueuses d'argile

    NASA Astrophysics Data System (ADS)

    Mobuchon, Christophe

    Phyllosilicates or layered silicates consist of individual layers with nanometric dimensions. In static fluids without external forces, attractive and repulsive colloidal forces acting between the colloidal layers lead to their self-organization on multiple length scales. Under flow, a wide range of complex rheological behaviors, including shear-thinning behavior and transition from fluid-like to solid-like behavior leading to thixotropic phenomena, is expected from structural evolution. Recently, layered silicates have attracted great interest as nanoscale fillers for reinforcement of polymers (PNCs) motivating the investigation of the structural properties of non-aqueous layered silicate suspensions. At the origin of this study, the linear and nonlinear viscoelastic properties of non-aqueous layered silicate suspensions were observed to depend on flow history. Hence, the ultimate aim of this work was to establish relationships between their rheological behavior and their structural properties. The picture of their inner structure has been achieved using a combination of light scattering techniques and advanced rheometric and microscopy measurements. The flow-induced orientation of the phyllosilicate has been quantified optically using linear dichroism measurements, and mechanically using a newly developed non-destructive method based on two-dimensional small amplitude oscillatory shear flow (2D-SAOS). The spatial distribution at the microscopic scale of the phyllosilicate has been inferred from small angle light scattering (SALS) patterns and directly observed using confocal laser microscopy (CLSM). The combination of these techniques allowed highlighting the microscopic and self-similar nature of non-aqueous phyllosilicate suspensions. The solid-like properties of these suspensions were consequently ascribed to the presence of space-filling networks made of mass fractal clusters. Under flow, the shear-thinning behavior of these suspensions was explained by the shear rate dependency of the microstructure characteristic length scale. By increasing the shearing amplitude, the characteristic length scale of the non-equilibrium microstructures was shown to decrease from high to low plateau values. This structural evolution with the shearing amplitude was attributed to a reversible shear-induced aggregation. Limited structural orientational changes were also observed in the vorticity plane with anisotropy and orientation that developed in the same range of shear rate as the shear-thinning behavior of the suspensions. Upon cessation of flow, the lack of orientational recovery was explicitly shown with the 2D-SAOS experiments, while the lack of structural recovery at the micro-scale was observed in CLSM. The thixotropic behavior of these suspensions is therefore due to local rearrangements at the nano-scale. The non-equilibrium structures were actually shown to persist upon cessation of flow leading to different metastable structures. This work has allowed us to elucidate the effect of the flow history on the linear and nonlinear viscoelastic properties of these suspensions.

  7. Etude par spectrometrie raman de corticosteroides derives de la fluocortolone: trimethylacetate et caproate.

    PubMed

    Gamot, A P; Vergoten, G; Saudemon, M; Fleury, G

    1985-05-01

    Les spectres Raman de trois corticostéroïdes: fluocortolone base, triméthylacétate et caproate de fluocortolone (TMAF et CAF) ontétéenregistrésàl'état polycristallin entre 150 et 4000 cm(-1). Une attribution des raies observées est proposée. Elle a montréla complexitédu problème poséàsavoir la différenciation de trois composés de structure trés voisine. Cependant quelques intervalles de fréquences contenant des raies spécifiques sont susceptibles d'e^tre utilisés afin de permettre l'identification des composésétudiés. Il convient en premier lieu de distinguer tout particulièrement les raies situées entre 1500 et 1800 cm(-1). Dans l'intervalle 1580-1690 cm(-1) celles-ci sont intenses et spécifiques de la structure conjuguée Delta(1,4) 3-one des corticostéroi des ce qui permet de distinguer la classe de médicamentàlaquelle appartiennent les substancesétudiées. La zone de fréquence comprise entre 1690 et 1750 cm(-1) témoigne non seulement de la présence d'une fonction cétonique sur la chai^ne latérale mais aussi de l'existence d'une fonction ester suivant que l'on y trouve respectivement une ou deux raies (fluocortolone base 1701 cm(-1); TMAF 1728, 1745 cm(-1); CAF 1723, 1745 cm(-1). La fluocortolone base présenteà1635 cm(-1) une raie qui n'est pas retrouvée chez les dérivès estérifiés. En second lieu, nous retiendrons les zones spectrales représentatives des chai^nes latérales estŕrifiées fixées sur le carbone C(21): chai^ne triméthylacétate 340-360, 570-610, 750-810 cm(-1) (dans cette dernière région commune au caproate et au triméthylacétate la différenciation des deux composés se fait grâceàla raieà796 cm(-1) absente dans le spectre du caproate); chai^ne caproate 1310-1350 cm(-1) (dans cet intervalle, le caproate présente un profil très particulier avec trois raies d'intensitévoisine). Cet ensemble de résultats doite^tre utilisépour identifier ces substances par spectroscopie Raman sur des quantitiés de l'ordre du picogramme provenant d'éluat d'HPLC.

  8. Etude linguistique du dialogue psychosomatique (A Linguistic Study of Psychosomatic Dialogue)

    ERIC Educational Resources Information Center

    Pouder, Marie-Christine

    1977-01-01

    A linguistic analysis of interviews between three patients and their psychiatrists and psychoanalysts which showed correspondence between the communication situation and the language used. The discussion includes reasons for choosing psychosomatic patients, lexical and syntactic analysis, and a short discussion of Harris's method of discourse…

  9. Vocational Guidance within the Context of the Democratization of Education. Rapports, etudes...S.129.

    ERIC Educational Resources Information Center

    Siebel, Anselm

    This paper, based on information concerning the current status of vocational guidance in various countries, describes the main trends in its development in the context of the democratization of education. The experiences of the following countries are reviewed: Austria, Czechoslovak Socialist Republic, Federal Republic of Germany, France, German…

  10. Etude des defauts apparaissant dans les amenagements interieurs des avions d'affaires

    NASA Astrophysics Data System (ADS)

    Charette, Emilie

    The evolution of the aeronautic industry led to the development of new materials for these high performance applications. Among other examples, composite sandwich structures are increasingly used for interior body panels of business airplanes. These structures are assembled and fixed to the fuselage using metallic inserts bonded inside the sandwich panels with an epoxy resin adhesive. A thin film of wood veneer covers the visible side of interior furniture in order to bring sophistication and esthetic to the interior design. However, due to multiple factors, surface defects frequently appear on the veneered side of the panel where inserts are located. Moreover the defects tend to appear months after the airplane delivery causing costly reparations. The sources of defects can be mechanical ( deformation due to an excessive tightening), chemical (shrinkage of the epoxy adhesive) or the result of hygrothermal exposition. It is therefore important to understand the source of such surface defects and ultimately prevent or control their appearance. The present thesis deals with defects from chemical and hygrothermal sources appearing on the composite panels used on the interior body of business jets after aging. The main objective was to identify and quantify phenomena causing the defects on the interior panels of business planes. This research project is the first part of a project sponsored by CRIAQ and NSERC. The interaction of several materials can lead to various phenomena causing the apparition of surface defects. The project was thus divided into three parts in order to study an increasingly complex problem. the first study deals with the characterization of the different constitutive materials taken separately. This first part focused on thermal, rheological and mechanical aspects of epoxy adhesives. It was shown that the two adhesives used have different mechanical properties and cure kinetic reactions. In addition, the mechanical properties of sandwich composites panels were studied. The second study focused on the analysis of hygrothermal influence on the adhesive and the composite sandwich panels taken separately. Humidity and temperature can have an important effect on the constitutive materials, it is therefore important to know their influence. Finally, the third part deals with the influence of hygrothermal aging on a structure combining all the different materials. Sample panels including fixing zones (insert and resin) were made at the industrial partner's facility according to the industrial procedure. Subsequently, the samples have undergone an accelerated aging. By using deflectometry system, changes in local curvatures with respect to the aging conditions were observed. A correlation between the material characterization results, the aging effects and the surface defect gravity was performed to evaluate the sources and the occurrence of defects. Recommendations have also been made to ensure the project continuity. This project, carried out in an industrial context with the collaboration of Centre de Recherche Industrielle du Quebec ( CRIQ), 3M Canada and the Chaire de recherche sur les composites hautes performances (CCHP) of the department of mechanical engineering of Ecole Polytechnique de Montreal, highlights the importance of the choice of methods and materials in the manufacturing of composite structures.

  11. PECVD de composes de silicium sur polymeres: Etude de la premiere phase du depot

    NASA Astrophysics Data System (ADS)

    Dennler, Gilles

    Since their first introduction in the early 90's, transparent barriers against oxygen and/or water vapor permeation through polymers, such as SiO 2, are the object of increasing interest in the food and pharmaceutical packaging industries, and more recently for the encapsulation of organic-based displays. It is now well known that these thin layers possess barrier properties only if they are thicker than a certain critical thickness, dc. For example, dc is around 12 nm in the case of SiO2 on KaptonRTM PI; below this value, the measured "Oxygen Transmission Rate" (OTR, in standard cm3/m2/day/bar) is roughly the same as that of the uncoated polymer. Until now, no detailed research has been carried out to explain this observation, but a hypothesis was proposed in the literature, based on island-like growth structure of the coating for d ≤ dc. According to this hypothesis, the surface energy of the polymeric substrates is so low that the Volmer-Weber (island-coalescence) growth mode occurs. We have aimed to verify this explanation, that is, to study the initial phase of silicon-compound (SiO2 and SiN) growth on four different polymeric substrates, namely polyimide (KaptonRTM PI), polycarbonate (LexanRTM PC), polypropylene (PP), and polyethyleneterephthalate (MylarRTM PET). Three different deposition methods were used, namely reactive evaporation of SiO, radio-frequency (RF) Plasma Enhanced Chemical Vapor Deposition (RF PECVD), and Distributed Electron Cyclotron Resonance (DECR) PECVD. In this latter case, the substrates were placed in three different positions: (i) in the active glow zone, (ii) downstream, and (iii) downstream, but shielded from photon emission (e.g. VUV) from the plasma. Angle-Resolved X-Ray Photoelectron Spectroscopy (ARXPS), Rutherford Backscattering Spectroscopy (RBS), and Scanning Electron Microscopy (SEM), the latter performed after Reactive Ion Etching (RIE) by oxygen plasma, revealed that growth indeed occurs in a Volmer-Weber mode in the case of evaporated films. The island coalescence was observed to occur at d = 1.2 nm, at which point the sticking coefficient of precursor species changes drastically. Finally, we have investigated the presence of an "interphase" between deposited coatings and the polymeric substrate. (Abstract shortened by UMI.)

  12. Contribution a l'etude de l'inactivation de micro-organismes par plasma

    NASA Astrophysics Data System (ADS)

    Benhacene-Boudam, Mustafa-Karim

    The present work is a deepening of some specific research aspects concerning medical device sterilization by ionized gases, that were initiated almost ten years ago and pursued since then by the "Sterilization team" of the Groupe de physique des plasmas. Initially, the thesis was directed at spore inactivation by atmospheric-pressure plasmas with the intent of showing that it was possible to reach sterility mainly by the action of UV photons, therefore minimizing damage to materials (in contrast to using chemically reactive species from the plasma) and, at the same time, achieving a greater control of the process through its better understanding. We actually succeeded in demonstrating the possibility of spore inactivation based on the dominant action of UV photons issued from an atmospheric-pressure plasma. However, the low inactivation efficiency and the practical difficulty of the atmospheric-pressure plasma used made us turn to low-pressure post-discharge sterilization systems. To comply with this new goal, we first characterized, essentially through emission spectroscopy, the flowing afterglow of a N2-O2 low-pressure discharge, concentrating on the properties and effects of the early and late post-discharges as far as sterilization is concerned. We demonstrated that the early afterglow is responsible for heavy damage to processed polymers but that it is possible to reduce its influence provided a minimum percentage of O2 is added in the N2-O2 mixture and also by moving away the plasma source from the sterilization chamber entrance. We then studied the combined effects, on the kinetics of spore inactivation, of the species (UV photons, radicals) issued from the plasma and of the heating of the petri dish, using B. atrophaeus spores as reference microorganisms. We clearly proved the existence of synergy between UV photons and heating in inactivating spores, provided UV photons and heating act simultaneously. Whatever the O2% in the mixture, and thus the UV intensity, the inactivation rate was also found to obey a fluence law and its dependence on temperature could be modeled by the Arrhenius relation. Keywords: sterilization, atmospheric-pressure plasma, low-pressure plasma, UV photons, bacterial spores, survival curves, UV and heating synergy.

  13. Machine learning etudes in astrophysics: selection functions for mock cluster catalogs

    SciTech Connect

    Hajian, Amir; Alvarez, Marcelo A.; Bond, J. Richard E-mail: malvarez@cita.utoronto.ca

    2015-01-01

    Making mock simulated catalogs is an important component of astrophysical data analysis. Selection criteria for observed astronomical objects are often too complicated to be derived from first principles. However the existence of an observed group of objects is a well-suited problem for machine learning classification. In this paper we use one-class classifiers to learn the properties of an observed catalog of clusters of galaxies from ROSAT and to pick clusters from mock simulations that resemble the observed ROSAT catalog. We show how this method can be used to study the cross-correlations of thermal Sunya'ev-Zeldovich signals with number density maps of X-ray selected cluster catalogs. The method reduces the bias due to hand-tuning the selection function and is readily scalable to large catalogs with a high-dimensional space of astrophysical features.

  14. Etudes de linguistique semitique et arabe (Studies of Semitic and Arabic Linguistics).

    ERIC Educational Resources Information Center

    Cohen, David

    Various aspects of Arabic and Semitic linguistics are discussed in this text. The nine chapters include: (1) fundamental Semitic vocabulary and the classification of southern dialects; (2) observations on nominal derivation by affixation in several Semitic languages; (3) an automatic analysis of literary Arabic; (4) "Addad" and…

  15. Fabrication et etude de cristaux photoniques pour les longueurs d'onde de telecommunication optique

    NASA Astrophysics Data System (ADS)

    Aboudihab, Ismail

    Nous avons fabrique et etudie des cristaux photoniques bidimensionnels et tridimensionnels. Les cristaux 3D sont constitues de microbilles de polystyrene autoassemblees. La structure inverse en BaTiO3 a ete aussi fabriquee, ou l'on remplace l'espace entre les microbilles par du BaTiO3, alors que les microbilles sont eliminees. Nous avons essaye en particulier de comprendre les differents phenomenes qui influencent la cristallisation de ces structures afin d'obtenir des films de meilleure qualite. Les cristaux bidimensionnels, constitues de cylindres vides imbibes dans un semiconducteur (As2S3 ou Si), sont obtenus par holographie laser. Nous avons montre que cette technique est tres interessante pour la production en serie de ces structures. Des guides d'ondes, des coupleurs, et des jonctions Y, imbibes dans des cristaux photoniques bidimensionnels, ont aussi ete fabriques. Des mesures optiques et des simulations numeriques ont ete menees dans le but de caracteriser ces structures.

  16. Etude de l'isolation hybride en vue de son application dans les transformateurs de puissance

    NASA Astrophysics Data System (ADS)

    Kassi, Koutoua Simon

    For nearly a century the conventional insulation (oil / cellulose complex) was the type of insulation used in the power transformers and most electrical power equipments. But the cellulose paper, the solid part of this insulation has many weaknesses. Indeed, the aging of cellulose paper in power transformers is accelerated by moisture, oxygen, metal catalysts, temperature, etc.). The risk of failures is thereby increased. Another major weakness of cellulose paper is its inability to protect the electrical transformer windings against the harmful effects of corrosive sulfur. Given all the weaknesses of cellulose paper, several studies have been conducted to evaluate the performance of aramid paper, which has better thermal properties. The aramid paper is currently used as high temperature insulation, combined with high fire point oils (synthetic and vegetable oils), mainly in electric traction transformers. The hybrid solid insulation is associated with mineral oil or with high fire point oils; it finds application in transformers of fixed and mobile substations. Manufacturing technology is controlled by manufacturers but operators of electrical networks do not have baseline data (standards) as diagnostic tools, allowing them to monitor the health/condition of the isolation in this new type of transformer. The overall objective of this research was to study the hybrid insulation and to demonstrate its potential use in power transformers. This overall objective has been subdivided into three specific objectives, namely: (i) improving the diagnostic of the condition of solid hybrid insulation and conventional solid insulation; (ii) diagnosing the condition of oils sampled from hybrid, high temperature and conventional insulation and finally (iii) investigating the ability of aramid paper and cellulose paper to protect the copper (electrical windings) against harmful effects of corrosive sulfur. In order to achieve these objectives, thermal accelerated aging were conducted in laboratory : • according to ASTM D1934 (American Society for Testing and Materials), four different type of insulation samples were considered, namely the oil impregnated hybrid insulation, oil impregnated cellulose insulation, oil impregnated high temperature insulation and paperless oil samples. Following the aging procedure, a local overheating (thermal fault) was applied on the paper sample using an experimental setup designed in our laboratory (first and second specific objectives). • according to the IEC (International Electrotechnical Commission)-62535, for mineral, synthetic, vegetable and silicones oils (third specific objective). The degree of polymerization by viscosimetry and the determination of the carbon oxides by dissolved gas analysis (DGA) were determined to assess the condition of the paper in conventional insulation compared to that of the hybrid insulation. Our results indicate that cellulose paper in the hybrid insulation is less degraded when compared to the conventional insulation. Since the life of a transformer is directly related to the solid insulation, these results suggest that hybrid transformer insulation has a higher life than conventional ones. Subsequently, a very good correlation between amounts of oxides of carbon and degree of polymerization was established. This relationship might help improving the accuracy when interpreting the results of the DGA for transformers (first specific objective). Regarding the second specific objective, we used four physicochemical diagnosis techniques (dissolved decay products 'DDP', Turbidity, interfacial tension (IFT) and water content) to assess comparatively the quality of oils sampled from the four types of insulation. According to our results, the oil of the hybrid insulation indicated better quality at a certain stage of aging and especially after the application of thermal stress on the solid insulation. For the third specific objective, a qualitative study followed by a quantitative ones provided the following results: aramid paper better protects copper against corrosive sulfur in mineral oil; synthetic ester oils are not corrosive; the vegetable oil is not corrosive but in the presence of cellulose paper, a degree of corrosiveness is observed and the aramid paper promotes formation of corrosive sulfur in silicone oils. Based on the obtained results, the feasibility of using hybrid insulation in power transformers is possible. Keywords : power transformer; hybrid insulation; high temperature insulation; conventional insulation; sub-stations; aramid paper; cellulose paper; degree of polymerization; dissolved gases analysis (DGA); mineral oils; vegetable oils; synthetic oils; corrosive sulfur.

  17. Etude de l'effet du gonflement par les solvants sur les proprietes du caoutchouc butyle

    NASA Astrophysics Data System (ADS)

    Nohile, Cedrick

    Polymers and in particular elastomers are widely used for personal protective equipment against chemical and biological hazards. Among them, butyl rubber is one of the most effective elastomers against chemicals. However, if this rubber has a very good resistance to a wide range of them, it is sensitive to non polar solvents. These solvents will easily swell the material and may dramatically affect its properties. This situation may involve a large risk for. butyl rubber protective equipment users. It is thus essential to improve the understanding of the effect of solvents on the properties of butyl rubber. The research that was carried out had two objectives: to identify the parameters controlling the resistance of butyl rubber to solvents and to study the effect of swelling on the properties of butyl rubber. The results show that the resistance of butyl rubber to solvents appears to be controlled by three main parameters: the chemical class of the solvent, its saturation vapor pressure and its molar volume. In addition, swelling affects butyl rubber mechanical properties in a permanent way. The effects can be attributed to the extraction of plasticizers by the solvent and to the degradation of the physico-chemical structure of the polymer network. This chemical degradation was linked to a phenomenon of differential swelling which seems to be controlled by the solvent flow inside the material. These results question some general beliefs within the field of protection against chemical risks. They also open new perspectives for the development of predictive tools relative to the behavior of butyl rubber in the presence of solvents

  18. Pratique d'apprentissage en ligne aux etudes superieures (Online Learning for Higher Education).

    ERIC Educational Resources Information Center

    Marchand, Louise

    2001-01-01

    Online learning requires new approaches to teaching and learning. At the University of Montreal, 28 graduate students in education and adult students specializing in educational technology attended an experimental distance education course. Students identified advantages and disadvantages of online learning/teaching and reflected on how the course…

  19. Etude et simulation des groupes convertisseurs-machines synchrones a six phases

    NASA Astrophysics Data System (ADS)

    Doyon, Jean-Francois

    Since many years, multiphase (n > 3) machines represent a growing research interest in the electrical machines domain. This type of machine can be used for many systems like automotive electrical traction, electric ship propulsion, wind farms or high-power industrial applications. Above all multiphase machines, the six phases wounded rotor synchronous machine brings a huge interest. Subsequently, using that kind of machine in any application requires a good understanding of the machine model and its respective converters. Hence, simulation represents a great way to study the behaviour and design of such applications that uses six phases wounded rotor synchronous machines. The present research concerns the study and simulation of six phase synchronous machinesconverters systems. From this project resulted the implementation of the six phases wound rotor salient pole synchronous machine in the Demos library of Matlab SimPowerSytems. In terms of study, a six phase machine electric drive is designed as well as a six phase machine implementation in a type 4 wind farm. The modeling of the six phase synchronous machine is fully detailed for the electrical part and the mechanical part. Then, the voltage source inverter electric drive with hysteresis control is conceived. Simulations of torque control, speed control and degraded mode of the machine are executed. The results illustrate the electric drive efficiency. This is followed by the type 4 wind turbine application of the machine. The wind farm is connected to a 120 kV grid, where a voltage drop fault appears at the 120 kV bar for a duration of six 60 Hz cycles. The results show a good operation of the regulators during the fault. This application is also subjected to a degraded mode, where results illustrate once again a good system regulation. Also, for the electric drive and the wind farm applications, a comparative study is made for the use of an asymmetrical versus symmetrical winding configuration of the machine. It is shown that for these two configurations, the total harmonic distortion seen from the source are similar. Finally, detailed model and average model of the converters are made for the electric drive and the wind turbine. The results show great similarity between the models.

  20. Etude Bacteriologique sur 30 Mois dans un Service de Brulés

    PubMed Central

    Chaibdraa, A.; Bentakouk, M.C.

    2008-01-01

    Summary Le pronostic des brûlures est souvent tributaire de complications infectieuses. Les objectifs de cette étude préliminaire rétrospective sont une évaluation de la flore microbienne et ses fluctuations selon la durée d'hospitalisation chez les patients du Centre des brûlés adultes de Annaba (Algérie). Ce travail porte sur 633 prélèvements microbiologiques positifs obtenus entre juin 2003 (inauguration du service) et décembre 2005. Selon le site de prélèvement la répartition est: cutané (78%), hémoculture (9%), prélèvement trachéo-bronchique (4%), uroculture (3%), sonde urinaire (3%), cathéter(3%). Les germes isolés sont: les staphylocoques (58%), les Pseudomonas (20%), le Candida albicans (5%), l'Acinetobacter (3%) et les autres germes (14%). Parmi les staphylocoques et les Pseudomonas recensés, respectivement 19% et 11% sont isolés la première semaine, contre 43% et 52% au-delà de 21 jours. Ces résultats confrontés aux données de la littérature confirment la prédominance du staphylocoque et du Pseudomonas. Le risque de contamination à partir des techniques invasives de réanimation est commun à toutes les équipes. La prolifération bactérienne est en relation avec la durée d'hospitalisation. Ces constatations doivent nous inciter à tirer bénéfice de l'expérience des autres services, en particulier sur les moyens, accessibles, de prévention de l'infection nosocomiale. PMID:21991102

  1. Etude cristallochimique de LiPN 2: Une structure derivée de la cristobalite

    NASA Astrophysics Data System (ADS)

    Marchand, Roger; L'Haridon, Paul; Laurent, Yves

    1982-07-01

    LiPN 2 has been prepared by reaction between Li 3N and P 3N 5 nitrides. The unit cell is tetragonal with a = 4.567(1) and c = 7.140(4) Å. The space group is I overline42d . The structure is related to the β cristobalite type and is isostructural with CaGeN 2. It is built up from a PN 4 tetrahedra framework in the holes of which the lithium atoms are localized. The values of the rotation angle ф of tetrahedra, {c}/{a} ratio and θ (NPN) angle have been discussed in relation to the parameter x of the nitrogen atoms.

  2. Rocket Motor Plume Technology (L’Etude des Jets des Moteures-Fusees)

    DTIC Science & Technology

    1993-06-01

    being normally limits the choice of material cartridge loaded or case bonded, to filled rubbers . Because of the higher The advantages of cartridge load...achieve very low scattering cofficients heat resistant/erosion resistant sub micron particles should be used. The material 3uch as Butyl; EPDM or other...chief source of smoke in charge chlorosulphonated polyethylene inhibitor formulations is due to unburnt rubber . These are normally heavily hydrocarbons

  3. Etude de la stabilite d'un avion BWB (Blended Wing Body) de 200 passagers

    NASA Astrophysics Data System (ADS)

    Legros, Clement

    The Blended Wing Body (BWB) is a type of innovative aircraft, based on the flying wing concept. This new type of airplane shows several advantages compared to the conventional airplanes : economy of fuel, reduction of the weight of the structure, reduction of the noise and less impact on the environment, increased payload capacity. However, this kind of aircraft has a lack of stability due to the absence of vertical tail. Several studies of stability were already realized on reduced size models of BWB, but there is no study on a 200 passengers BWB. That's why, the main objective of this present study is to integrate the engines and theirs pylons into the existing conceptual design of the BWB to analyze of their impact on its static and dynamic stability over the flight envelope. The conception of the BWB was realized with the platform of design CEASIOM. The airplane, the engines and theirs pylons were obtained in the geometrical module AcBuilder of CEASIOM. The various aerodynamic coefficients are calculated thanks to Tornado program. These coefficients allow realizing the calculations of stability, in particular with the longitudinal and lateral matrices of stability. Afterward, the BWB flight envelope is created based on aeronautical data of a similar airplane, the Airbus A320. From this flight envelope, we get back several thousand possible points of flight. The last step is to check the static and dynamic stability, using the longitudinal and lateral matrices of stability and the Flying Qualities Requirements, for every point of flight. To validate our study of stability, the already existing studies of stability of the Boeing 747 will be used and compared with our model.

  4. Structure electronique de nanorubans de graphene avec des contacts metalliques: Une etude ab initio

    NASA Astrophysics Data System (ADS)

    Archambault, Chloe

    Graphene, a graphite monolayer presenting novel exciting properties, has attracted much attention recently in the scientific community as well as in the high-technology industry. In electronics, nanoribbons -- narrow strips of graphene which happen to be semiconducting-- could possibly allow further miniaturization of electronic devices such as transistors because of their atomic thickness. On the other hand, once making devices, the problem of metallic contacts, which can have critical impact at the nanoscopic scale, cannot be evaded. For example, metal induced gap states may short-circuit very short devices. With this in mind, the interaction of gold, palladium and titanium contacts with finite size graphene nanoribbons has been studied using ab initio density functional theory calculations. This theoretical approach made it possible to study separately and then conjugate four important aspects of the metal-ribbon interaction: bonding, charge transfer, electrostatics and metal induced gap states. Another goal of this project was to study size effects related to the ribbons' dimensions and to estimate the minimal channel length necessary for a device to operate as expected without the unwanted effect of induced gap states. Aside from the high precision achieved, these calculations stand out from earlier studies because they take into account finite size effects which often prevail in small ribbons. Using this model for the metal-nanoribbon junction, it was shown that, as for two-dimensional graphene, the bonding between a ribbon and a metal can be of two types depending on the electronic configuration of the metal. In the first case, physisorption, weak bonding resulting in a large separation distance between ribbon and electrode, is illustrated by the gold contact. On the other hand, titanium, because of its high density of states at the Fermi level, binds more strongly with graphene nanoribbons. This chemisorption is characterized by strong hybridization between the metal and the ribbon's orbitals. This leads to the apparition of intense evanescent gap states in the ribbon. As for palladium, it represents an intermediate case showing some but not as much hybridization. For all three metals, right under the contact, we observe a net decrease of electron density in the ribbon in favour of the contact. Effectively, any kind of bonding is generally associated with charge transfer necessary to balance the work function difference. As expected, a metal with a large work function such as gold and palladium tends to attract electrons. However, this behaviour is surprising from titane whose work function is much smaller. This can only be explained by considering the large hybridization of the ribbon's orbitals. Moreover, the charge transfer is not restricted to the area under the contact as an evanescent charge can also be observed in the channel. This charge results from the occupation of metal induced gap states and its sign depends on the position of the charge neutrality point. The calculations presented don't take into account the effect of temperature. Nevertheless, the position of the Fermi level relative to the ribbon's bands suggests that at non-zero temperature, gold and palladium would p dope the graphene nanoribbons while titanium would have the opposite effect. The charge redistribution in the junction generates a molecular-sized dipole which is responsible for the slowly varying three-dimensional potential profile, a particularity of low dimensional systems. A potential barrier thus appears at the interface and controls band curvature in the device, but it can also constitute an obstacle to efficient charge injection. The intimate relation between the titanium contact and the ribbons seems to maximize screening and reduce considerably the height of the barrier, which could turn out to be beneficial. Finally, metal induced gap states slowly decaying in the channel have been observed directly in graphene nanoribbons for the first time. Their characteristic evanescent shape is clearly distinguishable. The extent of the gap states was measured to be on the order of a nanometer. It depends mostly on the ribbon's bandgap which varies both with its length and width. The bandgap, which can easily be measured experimentally, could thus be a useful tool to predict the penetration of gap states, a must-have information in order to limit the undesired effect of gap states since it sets for a device the minimal channel length (˜1-2 nm). In summary, these theoretical results could be used as a guideline in the conception of electronic devices made of graphene nanoribbons in which doping and potential profile need to be optimized while making sure that metal induced gap states do not compromise normal operation.

  5. Etude des interdiffusions en phase solide dans le contact Er/GaAs

    NASA Astrophysics Data System (ADS)

    Députier, S.; Guivarc'h, A.; Caulet, J.; Minier, M.; Guérin, R.

    1994-05-01

    Solid state interdiffusions between a thin film of erbium deposited under vacuum conditions and (001) and (111) GaAs substrates were investigated in the temperature range 350-800 ^{circ}C. Complementary analysis methods (RBS, X-ray diffraction) allow us to point out, according to annealing temperatures, successives steps of the interaction corresponding to different mixtures of phases, essentially binaries. These steps are strongly depending on the GaAs substrate orientation, especially the final step of the interdiffusions. On (001) GaAs, only two steps have been observed : no visible interaction is noticed between erbium and GaAs before 600 ^{circ}C ; the interaction begins at 600 ^{circ}C, evolves slightly and leads at 800 ^{circ}C to the nominal composition " Er{10}GaAs " which corresponds to a mixture of several phases Er5Ga3, Er and ErAs. On (111) GaAs, several steps of interaction have been found ; first of all, erbium reacts with the substrate at 400 ^{circ}C (Er5Ga3 + Er mixture), then the reaction is continuing at 600 ^{circ}C (Er5Ga3 + Er + ErAs mixture) before reaching at 800 ^{circ}C the nominal composition " Er{1,5}GaAs ", which is in fact a mixture of the three binaries ErAs + ErGa2 + Er3Ga5. It can be noticed that the 800 ^{circ}C annealing is not sufficient to reach the mixture of the phases ErAs + Ga which, according to the ternary phase diagram, should be the final stage of the interaction Er/GaAs. The analysis of the Er/GaAs interdiffusions shows that ErAs is the " key " compound around which the interaction progresses. This compound appears as an ideal candidate to realize epitaxial ErAs/GaAs heterostructures. Les interdiffusions en phase solide entre une couche mince d'erbium déposée dans des conditions d'ultra-vide et des substrats de GaAs orientés (001) et (111) ont été étudiées après des traitements thermiques d'une heure entre 350 et 800 ^{circ}C. L'utilisation de techniques complémentaires d'analyse (RBS, diffraction X) a permis de mettre en évidence, en fonction de la température de recuit, plusieurs étapes successives d'interaction correspondant à des mélanges de phases, essentiellement des binaires. Elles dépendent fortement de l'orientation du substrat de GaAs, en particulier l'étape finale des interactions. Sur GaAs (001), seules deux étapes ont été observées : avant 600 ^{circ}C, il n'y a pas d'interaction visible de l'erbium avec le substrat ; celle-ci ne s'amorce qu'à 600 ^{circ}C pour n'évoluer ensuite que faiblement et conduire, à 800 ^{circ}C, à une composition nominale " Er{10}GaAs ", mélange des phases Er5Ga3 + Er + ErAs. Sur GaAs (111), plusieurs étapes d'interaction sont observées : l'erbium réagit avec le substrat dès 400 ^{circ}C (mélange des phases Er5Ga3 + Er), puis l'interaction se poursuit à 600 ^{circ}C (mélange Er5Ga3 + Er + ErAs) avant d'atteindre à 800 ^{circ}C la composition nominale " Er{1,5}GaAs ", constituée d'un mélange de grains des trois binaires ErAs + ErGa2 + Er3Ga5. Il faut noter que le recuit à 800 ^{circ}C n'est pas suffisant pour atteindre le mélange de phases Ga + ErAs qui, selon le diagramme ternaire, devrait être le stade ultime de l'interaction Er/GaAs. L'analyse des interdiffusions Er/GaAs montre que ErAs est le composé " clé " autour duquel pivote l'interaction Er/GaAs. Ce composé apparaît comme un candidat idéal pour la réalisation d'hétérostructures épitaxiées ErAs/GaAs.

  6. Etude des interdiffusions en phase solide dans le contact Ni/AlAs

    NASA Astrophysics Data System (ADS)

    Députier, S.; Guivarc'h, A.; Caulet, J.; Poudoulec, A.; Guenais, B.; Minier, M.; Guérin, R.

    1995-04-01

    Solid-state interdiffusions between a thin film of nickel deposited under vacuum conditions and a thick layer of epitaxial AlAs on GaAs (001) and (111) substrates were investigated in the temperature range 200-600 ^{circ}C. Complementary analytical methods (RBS, X-ray diffraction, TEM) allow us to point out, according to annealing temperatures, successives steps of the interaction. These steps correspond either to ternary phases which were evidenced by the experimental determination of the Ni-Al-As phase diagram and labelled as A, B and D phases by comparison with the isostructural ternary phases in the Ni-Ga-As diagram or to mixture of ternaries and binaries, more or less strongly textured on the substrate. In fact, the nature of the observed phases is strongly depending on the AlAs substrate orientation, the kinetic of the reaction occurring being slower on AlAs(111) than on AlAs(001). On AlAs(001), a ternary B-phase + NiAl mixture is firstly observed, followed by a second mixture constituted of the ternary A-phase + NiAl and NiAs binaries, and finally, at the end of the interaction, the two binaries NiAl + NiAs appear. On AlAs(111), only two steps of interaction have been found; first of all, the ternary D-phase is obtained, before leading, at the end of the interaction, to the ternary B-phase + NiAl + NiAs mixture. In that case, the 600 ^{circ}C annealing is not sufficient to reach the mixture of the binaries NiAl + NiAs which, according to the ternary phase diagram, is the final stage of the Ni/AlAs interaction. The comparative study of the Ni/AlAs and Ni/GaAs interdiffusions shows that the binary NiAl is the “key” compound around which the Ni/AlAs interaction progresses when NiAs is the one of the Ni/GaAs interaction. The binary NiAl which is thermally stable and strongly textured on AlAs appears as an interesting candidate to prepare epitaxial NiAl/AlAs/GaAs heterostructures. Les interdiffusions en phase solide entre une couche mince de nickel déposée dans des conditions d'ultra-vide et des couches épaisses d'AlAs épitaxiées sur des substrats de GaAs orientés (001) et (111) ont été étudiées après des traitements thermiques d'une heure, sous balayage de gaz neutres, entre 200 et 600 ^{circ}C. L'utilisation de techniques complémentaires d'analyse (RBS, diffraction X, MET) a permis de mettre en évidence, en fonction de la température de recuit, plusieurs étapes successives d'interaction. Ces étapes correspondent soit à des phases ternaires, mises en évidence lors de la détermination expérimentale du diagramme Ni-Al-As et notées A, B, D par analogie avec celles du diagramme Ni-Ga-As, soit à des mélanges de phases constituées de binaires et/ou de ternaires, toutes ces phases étant plus ou moins fortement texturées sur le substrat. En fait, la nature des phases en présence dépend de l'orientation du substrat, la cinétique de réaction apparaissant plus lente pour l'interaction Ni/AlAs(111) que pour celle Ni/AlAs(001), les étapes successives sont observées : tout d'abord un mélange constitué de la phase ternaire B + NiAl puis un autre mélange : phase ternaire A + NiAl + NiAs et en fin d'interaction les deux binaires : NiAl + NiAs. Sur AlAs(111), seules deux étapes sont mises en évidence, la première correspond à la phase ternaire D, la seconde, en fin d'interaction, est constituée du mélange : phase B + NiAl + NiAs. On remarque dans ce cas le recuit à 600 ^{circ}C n'est pas suffisant pour atteindre le mélange des binaires NiAl et NiAs qui, selon le diagramme ternaire, est le stade ultime de l'interaction Ni/AlAs. L'analyse comparée des interdiffusions Ni/AlAs et Ni/GaAs montre que NiAl est le composé “clé” autour duquel pivote l'interaction Ni/AlAs alors que ce rôle était joué par NiAs lors des interdiffusions Ni/GaAs. Thermiquement stable et fortement texturé sur AlAs, le binaire NiAl apparaît comme un candidat prometteur pour la réalisation d'hétérostructures NiAl/AlAs/GaAs.

  7. Environmental Indicators. A Preliminary Set = Indicateurs d'environnement. Une etude pilote.

    ERIC Educational Resources Information Center

    Organisation for Economic Cooperation and Development, Paris (France).

    This document provides a preliminary set of environmental indicators by which to measure environmental performance. The indicators are patterned on the outline of the Organisation for Economic Cooperation and Development (OECD) "Report on the State of the Environment," a companion volume published in the same year. This volume is…

  8. Le Francais parle. Etudes sociolinguistiques (Spoken French. Sociolinguistic Studies). Current Inquiry into Languages and Linguistics 30.

    ERIC Educational Resources Information Center

    Thibault, Pierrette

    This volume contains twelve articles dealing with the French language as spoken in Quebec. The following topics are addressed: (1) language change and variation; (2) coordinating expressions in the French spoken in Montreal; (3) expressive language as source of language change; (4) the role of correction in conversation; (5) social change and…

  9. Language Teaching with the Help of Multiple Methods. Collection d'"Etudes linguistiques," No. 21.

    ERIC Educational Resources Information Center

    Nivette, Jos, Ed.

    This book presents articles on language teaching media. Among the titles are: (1) "Il Foreign Language Teaching e l'impiego degli audio-visivi" (Foreign Language Teaching and the Use of Audio Visual Methods) by D'Agostino, (2) "Le role et la nature de l'image dans l'enseignement programme de l'anglais, langue seconde" (The Role and Nature of the…

  10. Etude aerodynamique d'un jet turbulent impactant une paroi concave

    NASA Astrophysics Data System (ADS)

    LeBlanc, Benoit

    This research investigated the use of carbon nanotubes (CNTs) as a treatment to increase the permeability of a bacterial cell wall. Recombinant Escherichia coli BL21 (DE3) containing a plasmid that expressed Green Fluorescent Protein (GFP) and ?-lactamase were exposed to CNTs under various levels of agitation for different times. Fluorescence assay for GFP, optical absorbance for beta-lactamase activity, and Transmission Electron Microscopy (TEM) were used to determine the amount of released protein, and visually examine the permeability enhancement of the cells, respectively. It was found that more beta-lactamase was present in the culture fluid after treatment with CNTs in a dose dependent manner. Indeed, CNTs can lyse the cells up to 90% of maximum when compared to lysozyme treatment. Based on TEM, it is believed that this treatment damaged the cell walls to make E. coli permeable, causing periplasm proteins and enzymes to leak out into the medium. Consequently, CNTs can be used as lysis agents when it is undesirable to add an additional enzyme (lysozyme) to cause the release of intracellular proteins.

  11. Etude morphométrique de l'oreille externe chez les jeunes adultes

    PubMed Central

    Nyemb, Philippe Manyacka Ma; Sankale, Anne-Aurore; Ndiaye, Lamine; NDiaye, Aïnina; Gaye, Magaye

    2014-01-01

    Introduction Connaitre les dimensions normales de l'oreille externe constitue un pré-requis en chirurgie. Le but de ce travail est de déterminer les valeurs moyennes des différentes mesures morphométriques des oreilles gauches et droites dans notre population d’étude. Méthodes Notre groupe d’étude était constitué de 100 sujets adultes jeunes (50 femmes et 50 hommes) âgés de 18 à 25 ans, et exempts de traumatismes ou d'anomalies congénitale de l'oreille externe. Les différentes mesures répertoriées étaient représentées par: la hauteur totale de l'oreille, la largeur totale de l'oreille, la hauteur lobulaire, la largeur lobulaire, la distance tragus - anti-hélix, la distance tragus - hélix, ainsi que la projection de l'oreille. Résultats L’âge moyen de notre population d’étude était de 22 ans. La hauteur totale de l'oreille était respectivement de 61,6 et 60,3 mm chez les sujets de sexe masculin et féminin. La largeur totale retrouvée était respectivement de 32,5 et 30,8 mm. Pour toutes les distances mesurées, nous retrouvions des différences entre hommes et femmes, ainsi que d'un coté à l'autre. Conclusion Pour le clinicien, il est important de prendre en compte les mesures morphométriques de l'oreille externe non seulement dans un but diagnostic, mais également pour reproduire lors de sa reconstruction une oreille anatomiquement correcte. PMID:25932068

  12. Contributions a l'etude et a l'application industrielle de la machine asynchrone

    NASA Astrophysics Data System (ADS)

    Ouhrouche, Mohand-Ameziane

    The work presented in this thesis, done in the Electrical Drives Laboratory of Electrical and Computer Engineering Department, deals with the industrial applications of a three-phase induction machine (electrical drives and electricity generation). This thesis, characterized by its multidisciplinary content, has two major parts. The first one deals with the on-line and off-line parametric identification of the induction machine model necessary to achieve accurate vector control strategy. The second part, which is a resume of a research work sponsored by Hydro-Quebec, deals with the application of an induction machine in Asynchronous Non Utility Generators units (ANUG). As it is shown in the following, major scientific contributions are made in both two parts. In the first part of our research work, we propose a new speed sensorless vector control strategy for an induction machine, which is adaptive to the rotor resistance variations. The proposed control strategy is based on the Extended Kalman Filter approach and a decoupling controller which takes into account the rotor resistance variations. The consideration of coupled electrical and mechanical modes leads to a fifth order nonlinear model of the induction machine. The load torque is taken as a function of the rotor angular speed. The Extended Kalman Filter, based on the process's nonlinear (bilinear) model, estimate simultaneously the rotor resistance, angular speed and the flux vector from the startup to the steady state equilibrium point. The machine-converter-control system is implemented in MATLAB/SIMULINK environment and the obtained results confirm the robustness of the proposed scheme. As in the electrical drives erea, the induction machine is now widely used by small to medium power Non Utility Generator units (NUG) to produce electricity. In Quebec, these NUGs units are integrated into the Hydro-Quebec 25 kV distribution system via transformer which exhibit nonlinear characteristics. We have shown by using the ElectroMagnetic Program (EMTP) that, in some islanding scenarios, i.e. that the NUG unit is disconnected from the power grid, in addition to frequency variations, appearence of high an abnormal overvoltages, ferroresonance should occur. As a consequence, normal protective devices could fail to securely operate, which could cause serious damages to the equipment and the maintenance staff. This result, established for the first time , can be useful to improve the reliability of the NUGs units and is considered important by the power engineering community. This has led to a publication in the John Wiley & Sons Encyclopedia of Electrical and Electronics Engineering which will be available in February 1999 ( http://www.engr.wisc.edu/ ece/ece).

  13. Etude de la consolidation gravitaire en colonnes des remblais miniers cimentes en pate

    NASA Astrophysics Data System (ADS)

    El Aatar, Omar

    2011-12-01

    The challenge of underground mines backfilling in Abitibi region remains a major topic of investigation by many researchers in recent decades. For example, it has been observed in the backfilled stopes that the top of the fill settles systematically few days after its placement (by an average value varying between 0.9 and 1.5 m observed at Louvicourt mine). In addition, the strength of the cemented paste backfill (CPB) increases substantially, almost three times between the top and bottom of the backfilled stope. Some studies have also shown that the strength (unconfined compressive strength or UCS) of in situ CPB core specimens was 2 to 4 times of that of specimens of the equivalent lab-prepared CPB poured into plastic moulds. Among the many possible causes which could explain these observations, one can mention the self-weight consolidation of CPB. The main objective of this research is to understand the physical phenomena that govern the mechanical strength development within paste backfill after placement. To this end, three PVC columns, each of 3 m high, were manufactured and installed at the Louvicourt (LVT) mine and LaRonde (LRD) mine backfill plants to be in-filled. The column tests performed at the Louvicourt mine backfill plant allowed simulating different drainage configurations of a backfilled stope, namely, full drainage, partial drainage and no drainage while column tests performed at the LaRonde mine allowed comparing the response of three different paste backfill mix recipes for unique drainage condition: combined lateral and vertical drainage. Before the columns in-filling, the effect of mixing time on the slump height value of CPB was evaluated. Each column was then in-filled with CPB having a slump height similar to that of the fill used underground and in two sequences of in-filling of about 1.45 to 1.5 m over a time period of 24 hours. The monitoring of in-filled columns with CPB lasted for 5 days and consisted of measuring the amount of drainage water along with the observed settlement at the top surface of CPB column at time intervals of 1 hour. For the Louvicourt mine columns, several CPB core samples were extracted after 45 days curing time for experimental characterization of their mechanical, physical and hydro-geochemical properties. For the LaRonde mine columns, pore pressure and suction were measured using pressure sensors installed along the column height. The results obtained show that the maximum amount of drainage water (fully drained column) does not exceed 15% of the total water of the CPB, the maximum strength of CPB is reached with the fully drained column (2.9 MPa after 87 days of curing) and that the behavior of a backfilled stope at Louvicourt mine would be closer to either fully drained or partially drained column configurations. A clear distinction of the microstructure as a function of columns depth with the highest values of porosity and specific surface areas were observed in the case of drained CPB.

  14. Etude par spectroscopie vibrationnelle des niobates de sodium et d'argent de structure perovskite

    NASA Astrophysics Data System (ADS)

    Husson, E.; Repelin, Y.

    Infrared and Raman spectra of the niobates NaNbO 3 and AgNbO 3 of perovskite structure are analysed. An assignment of the frequencies is proposed. The influence of the antiferroelectric direction upon the NbO bonds is shown, as the influence of the A cation upon the AO and NbO bonds.

  15. Etude d'un concept de coeur hybride refroidi a l'eau supercritique

    NASA Astrophysics Data System (ADS)

    Delattre, Baptiste

    Facing the current weather and energy global problem, Canada chose to develop a reactor cooled by water at supercritical conditions (SCWR). Inspired by the current CANDU-6 pressure tube technology, this concept should allow to save a substantial amount of efforts for developping a brand new kind of reactor by using the well-known pressure tube CANDU design. In fact, this type of reactor should be able to reach a better energy efficiency as well as other essential criteria about safety, security, non-proliferation... Nevertheless, there are still a lot of technology challenges to be dealt with to satisfy the differents obligations related to the use of supercritical water (SCW). Thus, materials to use remain undetermined because of a 25 MPa operating pressure and a 650.C temperature for the SCW coolant. Actually, materials in presence of SCW should be able to avoid too much corrosion and remain low neutrons absorbers. Additionnaly, the use of a light water coolant makes the neutronic absorption more important than in CANDU heavy-water cooled reactors. Additionally, a positive coolant void reactivity (CVR) and safety related problem remains among the challenges to overcome for developping a SCWR. Bringing about a solutions to all these problems remains very difficult and that's why some concessions on these criteria have to be made in order to achieve a viable reactor. This study presents some thougts and works in that direction. Originally developped in early studies about thermodynamic cycle optimization for a SCW power plant, a new hybrid reactor concept with two channels types has arise. To this purpose, we imagine a pressure tube core design but with two different types of channels: . Some channels have thermodynamic conditions where water goes through a supercritical state. . The other channels have "CANDU like" thermodynamic conditions allowing the flow of pressurized light water under sub-critical conditions. These two kinds of features should mitigate the drawbacks and constraints of a whole SCWR core while keeping some of the benefit of the SCW use (improved energy efficiency). The aim of this study is to determine whether or not this kind of hybrid core with two types of channels is viable. To this purpose we used neutronics as thermalhydraulic models. First of all, in this thesis, we describe the SCWR-development history and specific back- ground with bibliography commentaries and a global description of the hybrid reactor developped. Secondly, we provide a brief theorical review of the neutronics and thermalhydraulics concepts used in the DRAGON, DONJON and ARTHUR calculation codes. Afterwards we will be considering some cell and core models and their description. Among others, some coupled neutronics-thermalhydraulic calculations have been done. This is followed by a presentation of the results we obtained and a discussion of the viability of our reactor. Finallly, we conclude.

  16. Etude descriptive et analytique du cancer de l’œsophage au Togo

    PubMed Central

    Oumboma, Bouglouga; Mawuli, Lawson-Ananissoh Laté; Aklesso, Bagny; Laconi, Kaaga; Datouda, Redah

    2014-01-01

    Introduction Décrire les aspects épidémiologiques, cliniques, endoscopiques et histologiques du cancer de l’œsophage (CO) au Togo. Méthodes Il s'agit d'une étude rétrospective descriptive et analytique menée sur 8 ans (Janvier 2005-Décembre 2012) dans le service d'hépato-gastroentérologie (HGE) du CHU Campus de Lomé. Etaient inclus les dossiers des patients hospitalisés pour CO confirmé histologiquement. Résultats Sur 8 ans, 24 patients remplissant nos critères d'inclusion ont été retenus soit 3cas de CO par an et 0,55% des hospitalisations. L’âge moyen des patients était de 57,08 ans (extrêmes: 32 et 82 ans). La dysphagie et l’épigastralgie étaient les motifs d'hospitalisation les plus rencontrés. L'alcool (n=15), le tabac (n=13) étaient les facteurs de risque les plus présents. A la fibroscopie, les lésions étaient ulcéro-bourgeonnantes et hémorragiques (n=12), ulcéro-bourgeonnantes (n=5); ces lésions siégeaient au niveau du 1/3 inférieur (n= 11), à l'union 1/3 supérieur 1/3moyen de l’œsophage (n= 13) et aucun au niveau du 1/3 supérieur. Seize lésions étaient des carcinomes épidermoïdes et 3 des adénocarcinomes. L’évolution dans le service a été fatale dans 2cas; 16 patients avaient été transférés en chirurgie pour des soins palliatifs et 5 patients (20,8%) étaient perdus de vue. Conclusion Le CO semble en augmentation au Togo. L'alcool et le tabac sont les facteurs de risque et le pronostic sévère dans notre série est lié au retard diagnostic. Son dépistage précoce passe par une consultation rapide devant toute dysphagie chez un sujet de 50 ans et plus. PMID:25883742

  17. Etude des facteurs de risque du retard de croissance intra-utérin à Lubumbashi

    PubMed Central

    Moyambe, Jules Ngwe Thaba; Bernard, Pierre; Khang'Mate, Faustin; Nkoy, Albert Mwembo Tambwe A; Mukalenge, Faustin Chenge; Makanda, Daudet; Twite, Eugene; Ndudula, Arthur Munkana; Lubamba, Cham; Kadingi, Arnauld Kabulu; Kayomb, Mutach; Kayamba, Prosper Kalenga Muenze

    2013-01-01

    Introduction Dans notre milieu, il n'existe aucune politique de prévention du Retard de Croissance Intra-Utérin (RCIU) clairement défini. L'objectif de ce travail était d'identifier les facteurs de risque de RCIU afin de proposer une stratégie de lutte contre cette pathologie en agissant surtout sur des facteurs pouvant faire l'objet d'une action préventive. Méthodes Une étude cas-témoins a été menée dans 11 centres hospitaliers de Lubumbashi en République Démocratique du Congo, de Janvier 2010 à Juin 2011, dans le but d'identifier les facteurs de risque du retard de croissance intra-utérin (RCIU). Au total 420 gestantes (cas et témoins) avec grossesse monofoetale d'au moins 24 semaines d'aménorrhée ont été inclues dans l'étude. Les cas correspondaient aux gestantes dont le poids du fœtus était resté inférieur au 10 eme percentile des courbes de référence d'Alexander, après 2 échographies successives réalisées à intervalle de 4 semaines. Les témoins correspondaient aux gestantes dont le poids du fœtus était supérieur ou égal au 10 eme percentile de mêmes courbes. A chaque cas a été apparié un témoin de même parité porteur d'une grossesse de même âge. Résultats L'analyse univariée a identifié comme facteurs de risque: la taille maternelle. Conclusion L'amélioration du niveau socio-économique des populations, la lutte contre le paludisme et les consultations prénatales mieux organisées couplées à une meilleure éducation sanitaire et nutritionnelle peuvent contribuer sensiblement à la réduction de la fréquence du RCIU à Lubumbashi. PMID:23504392

  18. Etude du stockage de l'hydrogene sur des nanostructures de carbone microporeuses

    NASA Astrophysics Data System (ADS)

    Poirier, Eric

    2007-12-01

    Le stockage de l'hydrogene par adsorption sur des adsorbants nano-structures a ete etudie sous differentes conditions de pression et de temperature. Les adsorbants etudies sont principalement des nanotubes de carbone a simple paroi ainsi que des structures metallo-organiques. Les mesures ont ete realisees a l'aide de systemes gravimetriques et volumetriques tres sensibles specialement mis au point pour de petits echantillons necessitant un degazage in situ. Les appareils developpes, au nombre de quatre, comprennent deux systemes gravimetriques et deux systemes volumetriques. Ensemble, ces systemes couvrent la plage de pressions (0-100) bars ainsi que la plage de temperatures (77-295) K. Les differentes analyses montrent que l'adsorption d'hydrogene sur les adsorbants nano-structures etudies est maximale a 77 K et varie entre environ (1.5 et 4) % masse. A temperature ambiante, l'adsorption croit lineairement avec la pression et demeure sous les 1% masse pour des pressions inferieures a 100 bars. L'adsorption d'hydrogene sur ces materiaux dans ces conditions se compare notamment a celle obtenue sur des charbons actives. La modelisation de l'adsorption a egalement ete realisee dans des conditions cryogeniques a l'aide du modele de Dubinin-Astakhov sous une forme adaptee pour l'adsorption supercritique. Les enthalpies d'adsorption calculees a partir de ce modele varient sous les 6 kJ/mole et sont donc consistantes avec des processus de physisorption. L'applicabilite du modele de Dubinin-Astakhov suggere que l'adsorption d'hydrogene puisse etre representee par un processus de remplissage des pores par un pseudo-liquide. Ces travaux s'inscrivent dans un contexte ou la capacite d'adsorption reelle des nanostructures de carbone est sujette a la controverse. En consequence, l'approche experimentale adoptee se distingue par les differentes demarches mises de l'avant pour l'obtention de mesures fiables sur des echantillons de faibles masses ainsi que par son caractere comparatif. Ces demarches incluent le developpement, l'etalonnage et la contreverification de systemes de mesures volumetriques et gravimetriques sensibles au microgramme. Ces systemes sont de plus adaptes au degazage sous vide et a haute temperature des echantillons. La mise au point d'un systeme de controle de temperature sur un petit volume pour des mesures a hautes pressions et basses temperatures constitue egalement un aspect original de ces travaux. De plus, d'un point de vue davantage theorique, cette these se caracterise par la modelisation de l'adsorption supercritique d'hydrogene sur differents materiaux et la derivation d'une expression pour l'enthalpie d'adsorption independante de la temperature a l'aide du modele de Dubinin-Astakhov.

  19. KIR haplotypes defined by segregation analysis in 59 Centre d'Etude Polymorphisme Humain (CEPH) families.

    PubMed

    Martin, M P; Single, R M; Wilson, M J; Trowsdale, J; Carrington, M

    2008-12-01

    The killer cell immunoglobulin-like receptor (KIR) gene cluster exhibits extensive allelic and haplotypic diversity. Variation at the locus is associated with an increasing number of human diseases, reminiscent of the HLA loci. Characterization of diversity at the KIR locus has progressed over the past several years, particularly since the sequence of entire KIR haplotypes have become available. To determine the extent of KIR haplotypic variability among individuals of northern European descent, we genotyped 59 CEPH families for presence/absence of all KIR genes and performed limited allelic subtyping at several KIR loci. A total of 20 unique haplotypes differing in gene content were identified, the most common of which was the previously defined A haplotype (f = 0.52). Several unusual haplotypes that probably arose as a consequence of unequal crossing over events were also identified. Linkage disequilibrium (LD) analysis indicated strong negative and positive LD between several pairs of genes, values that may be useful in determining haplotypic structure when family data are not available. These data provide a resource to aid in the interpretation of disease association data involving individuals of European descent.

  20. Methodes de calcul des forces aerodynamiques pour les etudes des interactions aeroservoelastiques

    NASA Astrophysics Data System (ADS)

    Biskri, Djallel Eddine

    L'aeroservoelasticite est un domaine ou interagissent la structure flexible d'un avion, l'aerodynamique et la commande de vol. De son cote, la commande du vol considere l'avion comme une structure rigide et etudie l'influence du systeme de commande sur la dynamique de vol. Dans cette these, nous avons code trois nouvelles methodes d'approximation de forces aerodynamiques: Moindres carres corriges, Etat minimal corrige et Etats combines. Dans les deux premieres methodes, les erreurs d'approximation entre les forces aerodynamiques approximees par les methodes classiques et celles obtenues par les nouvelles methodes ont les memes formes analytiques que celles des forces aerodynamiques calculees par LS ou MS. Quant a la troisieme methode, celle-ci combine les formulations des forces approximees avec les methodes standards LS et MS. Les vitesses et frequences de battement et les temps d'executions calcules par les nouvelles methodes versus ceux calcules par les methodes classiques ont ete analyses.

  1. Etudes sur la gravitation: Theories alternatives en 2+1 et 3+1 dimensions

    NASA Astrophysics Data System (ADS)

    Edery, Ariel

    This thesis contains four articles on gravitation of which three have been published in scientific journals and one has been submitted for publication. The four articles divide naturally into two parts. Chapter 1 contains two articles on conformal gravity, a 3 + 1 dimensional theory of gravity and chapter 2 contains two articles on 2 + 1 dimensional topologically massive gravity. Conformal gravity is a metric theory of gravitation which is generally covariant like Einstein gravity but also requires the action to be invariant under conformal transformations of the metric. The novel feature of the solution is a term in the metric that grows linearly with the radius. This linear term, which plays a significant role on large distance scales, can then be used to imitate the effects of the dark matter that is presumed to exist in abundance on galactic scales. In the first and second article, we test the viability of the vacuum solution of conformal gravity. In the first article we calculate the deflection of light due to a spherically symmetric source and obtain a remarkably simple result: besides the usual Einstein deflection, we obtain an extra deflection that increases linearly as the ``impact parameter'' increases (valid for small deflections). In both analyses no dark matter has been included. We explain clearly in our first article the reasons for the discrepency between the two results. In the second article, we study in detail the geometrical properties and the causal structure of the vacuum solution to conformal gravity. At infinity the space-time is not flat but conformal to flat. Through the use of Penrose (conformal) diagrams, we demonstrate that certain space- times, corresponding to certain parameters in the metric, do not allow light to scatter from infinity to infinity. For those which do, we obtain the trajectories and the deflection of light for arbitrary large values of r0 (the radius of closest approach). To simplify the study of gravity, it is common to study a 2 + 1 dimensional model. However, in 2 + 1 dimensions, the analog to Einstein gravity is trivial. The space-time outside sources is flat and particles at rest do not interact. The odd dimensional space-time allows one to include a gravitational Chern-Simons term called a topological mass term because it gives mass to the graviton. In article three and four, we consider localized mass and spin sources in the full non-linear theory. We obtain solutions for both of Vuorio's sectors. In article 3 we demonstrate that delta function sources, while allowed in the linearized theory are not consistent with the full non-linear field equations. In article four, we consider how to embed point sources in Vuorio's cosmological sector and discuss the metric solution for the case when observers are near and far away from the source. (Abstract shortened by UMI.)

  2. Etude du comportement hydrogeologique de couvertures avec effet de barriere capillaire faites entierement de materiaux miniers

    NASA Astrophysics Data System (ADS)

    Kalonji, Alex Kabambi

    The acid mining drainage (AMD) generating mine sites must be restored to limit their long-term contamination of the environment. At the end of mining operations, covers with capillary barrier effects (CCBE), generally made of natural materials soils, are used as an oxygen barrier to isolate the tailings that generate acid mining drainage (AMD) from their immediate environment. Due to economic and social acceptability contraints and to the environmental impact of stripping (footprint) of natural soil pits, mining companies are increasingly interested in using non-acid generating waste rock as a substitute for natural soils as base materials to form capillary break layers in covers. The overall objective of this study was to evaluate the hydrogeological behaviour of CCBE made entirely of mining materials (desulphurized tailings from a desulphurization process and non-acid generating waste rock). The specific objectives of this project were : 1) to characterize the hydrogeological properties of waste rock (with truncated size) and desulphurized tailings; 2) to evaluate in laboratory instrumented columns the effectiveness of CCBE made entirely of mining materials; 3) to simulate the column tests using a 1D numerical code to model the fluid (water and gas) flow in the unsaturated media; and 4) to validate with 2D numerical modeling the ability to restore LaRonde tailings impoundment (Agnico Eagle Mines Limited) using a CCBE made of low-sulfide tailings and non-acid generating waste rock. To achieve the objectives, samples of waste rock were collected from Bousquet waste rock pile and tailings from the ore concentration plant before being pumped to the tailings impoundment. Desulphurized tailings with less than 2% S were produced in order to construct a non-reactive CCBE. After the physical, chemical, mineralogical and hydrogeotechnical characterization of cover materials, laboratory physical models of CCBC in instrumented columns were performed. Three configurations were tested. The first two columns had a different waste rock grain size (0-20 mm and 0-50 mm) in their lower coarse layers, and the tailings were introduced at a high solid percent, approximatively 74% (simulating mechanical deposition). The third column also had waste rock with particle size 0-50 mm in its bottom coarse layer, but with tailings placed a lower solid percent, approximatively 55% (simulating hydraulic deposition). The particle size of the coarse waste rock in the top layers was set at 0-50 mm for all three columns. Several cycles of wetting drainage in the three columns were performed. The results of these laboratory investigations in terms of volumetric water content and suction profiles confirm the potential of non-acid generating waste rock to be used in the capillary break layers of CCBE. To assess the long-term performance, several scenarios of numerical modeling were performed using Vadose/W 2007 numerical codes, by Geoslope int. A variation of the depth of the water table and natural and extreme climatic conditions were considered in this parametric study. The results of these predictions confirmed the long-term effectiveness of covers with mine waste rock in capillary break layers. The effectiveness was evaluated in terms of oxygen flux at the interface between the moisture-retaining layer (MRL) and the bottom capillary break layer. Under natural and extreme climatic conditions (two months without infiltration), and a variation of the depth of the water table level from 2 to 6 m, cumulative oxygen flux over a one year period varied between 10.6 and 97.5 g/m 2/year. For extreme climatic conditions, and for the same variation of the depth of the water table, the oxygen flux varied between 14.3 and 117.9 g/m2/year. The highest oxygen flux (117 g/m2/year) was obtained for a water table depth of 6 m under extreme climatic conditions. The influence of the particle size contrast between the water retention layer and the bottom capillary break layer on the oxygen flux was further highlighted using relatively fine and coarse sand in the coarse bottom layer. The numerical modeling results obtained with the coarse sand were almost similar to those obtained with waste rock. In the absence of the strong contrast (when the relatively fine sand was used), the water retention layer was drained and the oxygen flux which reached at the bottom of this layer increased considerably. The water table depth, the grain size, and the hydraulic contrast between the MRL and the bottom capillary break layer (CBL) proved to be the key parameters of the simulated model. In field conditions, CCBE are often inclined, and that this inclination can affect the performance of the cover to control the migration of oxygen. 2D modeling was also performed. The numerical model was built to represent approximatively the case of one of the dams of LaRonde tailings impoundment. Preliminary results show that CCBE made entirely of mining materials are effective even when placed over slopes. The degree of saturation of the two slopes in the numerical model was higher than 85%. The influence of the slope has not significantly affected yet the performance of the cover for the model studied in this thesis. The cumulative oxygen flux over one year at the bottom of the MRL (for horizontal distance of 182 m of the numerical model) are 4031.3g (22.1 g/m2/year) and 4617.7g (25.3 g/m2/year) for natural and extreme climatic conditions respectively. This study confirms that waste rocks have good potential to be used as capillary break materials in the configuration of such CCBE. Thereby, it is suggested that the option of using only mining materials be included in the analysis of the optimal mode of mine reclamation. This project also suggests that good management of the tailings and waste rock produced during mining operations will provide the materials which could then be used to restore the site. More research is recommended to further investigate this reclamation option through field experimental cells. If further research validates the laboratory results at the intermediate scale, the use of mining materials would be considered as an effective option for CCBE used to control post-closure pollution. This scenario could reduce the construction costs while promoting the social acceptability of mining projects by reducing the use of natural soils.

  3. Etude du transfert thermique conjugue dans les cavites rectangulaires en convection naturelle

    NASA Astrophysics Data System (ADS)

    Nouanegue, Herve Frank

    Energy conservation is one of the most important areas of research and development. In parallel and in conjunction with it, developing clean energy technologies using renewable energy sources is similarly an important area to provide a sustainable energy supply. In this way, the quality of life will continue to flourish and at the same time the environment will be protected. For this purpose, devices operating on the principal of passive utilization techniques are used in different applications such as solar collectors, passive cooling and heating of buildings and others. Many of these applications make use of open and/or closed enclosures having different geometries, in which heat transfer by natural convection is used often with conjunction of conduction and surface radiation. To have the best thermal performance of these devices, the understanding of conjugate heat transfer in basic geometries is essential. The aim of this thesis is to study the influence of conduction and radiation heat transfer on natural convection in rectangular enclosures with different geometries and properties. A mathematical model of the system is developed which combines heat transfer by convection, conduction and radiation. A numeric code based on the volume control method is developed to simulate open and close systems with different geometries, in which the conservation equations of mass, momentum and energy are solved using the control volume method and the radiation heat exchange equations are added by calculating radiative heat flux on the emitting surfaces and treating it as a local heat source for the conjugate heat transfer by the three modes. Four specific configurations have been studied. The first one is a closed square inclined cavity containing a massive wall. The second configuration is an open cavity. The last two configurations involve passive cooling and heating systems in which the air circulates in long vertical channels. Numerical results for all the configuration show that radiative heat transfer represents an important part of the total heat transfer for all studied configurations. In the case where surfaces are assumed to be black bodies, this part is at least 25% and can increase up to 97%, i.e. air circulation is enhanced by surface radiative exchange. On the other hand, it is shown that heat exchange by surface radiation makes the surface temperatures more uniform as a result of which natural convection is reduced. As expected, the wall conductance is an important parameter in the conduction heat transfer through the wall and hence in the thermal performance of the massive wall. More specifically for each studied case, the obtained results are the following: (i) the close cavity inclination has a significant effect on the flow field; its effect is enhanced when the heat source is placed in the upper part of the flow domain. (ii) the aspect ratio of the open cavity affects the air circulation but its influence on the heat transfer is less important; (iii) the heat transfer by natural convection increases with the wall conductance for the case of solar chimney, and thus, the ventilating capacity of the channel is enhanced; (iv) the thermal efficiency of the passive system with thermal mass is reduced when the heat exchange by surface radiation is accounted for and the temperature difference between both external vertical boundaries increases.

  4. Etude des performances de solveurs deterministes sur un coeur rapide a caloporteur sodium

    NASA Astrophysics Data System (ADS)

    Bay, Charlotte

    The reactors of next generation, in particular SFR model, represent a true challenge for current codes and solvers, used mainly for thermic cores. There is no guarantee that their competences could be straight adapted to fast neutron spectrum, or to major design differences. Thus it is necessary to assess the validity of solvers and their potential shortfall in the case of fast neutron reactors. As part of an internship with CEA (France), and at the instigation of EPM Nuclear Institute, this study concerns the following codes : DRAGON/DONJON, ERANOS, PARIS and APOLLO3. The precision assessment has been performed using Monte Carlo code TRIPOLI4. Only core calculation was of interest, namely numerical methods competences in precision and rapidity. Lattice code was not part of the study, that is to say nuclear data, self-shielding, or isotopic compositions. Nor was tackled burnup or time evolution effects. The study consists in two main steps : first evaluating the sensitivity of each solver to calculation parameters, and obtain its optimal calculation set ; then compare their competences in terms of precision and rapidity, by collecting usual quantities (effective multiplication factor, reaction rates map), but also more specific quantities which are crucial to the SFR design, namely control rod worth and sodium void effect. The calculation time is also a key factor. Whatever conclusion or recommendation that could be drawn from this study, they must first of all be applied within similar frameworks, that is to say small fast neutron cores with hexagonal geometry. Eventual adjustments for big cores will have to be demonstrated in developments of this study.

  5. Littoral Infrared Ship Self Defence Technology Studies (Autodefense cotiere infrarouge des navires etudes technologiques)

    DTIC Science & Technology

    2014-05-01

    Modeling Radiometry Ship signature control Surveillance 14. Abstract Task Group Number 51 (RTG-51/SET-088), titled “Littoral Infrared Ship...Centre Renaissancelaan 30, 1000 Bruxelles Armaments Department ITALIE 9-11, Drumul Taberei Street CANADA Centro Gestione Conoscenza Sector 6...Distribučné a Defence R&D Canada informačné stredisko STO Department of National Defence ITALY Demänová 393 305 Rideau Street, 9th Floor Centro Gestione

  6. Etude d'un systeme de trigeneration decentralise en climats canadiens

    NASA Astrophysics Data System (ADS)

    Allaire Tanguay, Dominique

    Ce mémoire présente l'étude d'un système de trigénération ou CCHP (combined cooling, heating and power) au gaz naturel fournissant les besoins thermiques à un immeuble à logement typique de 13 étages. Un groupe électrogène permettant de générer de l'électricité tout en fournissant de l'eau chaude assure le chauffage du bâtiment et de l'eau chaude sanitaire tandis qu'une machine à absorption ammoniac-eau permet de transformer cette chaleur en puissance frigorifique afin de climatiser le bâtiment en période chaude. Le modèle de cette machine à absorption a spécialement été conçu pour fonctionner avec une température de désorption basse et permet d'évaluer les performances de telles machines dans des situations hors design. Ce modèle à été vérifié à l'aide d'autres modèles avérés et propose des coefficients de performance de l'ordre de 0,7 à 0,8. L'évaluation des performances horaires de ce système est présentée pour une année standard sous trois climats canadiens. Ces performances sont ensuite comparées aux différentes méthodes employées pour assurer ces besoins ainsi que pour générer l'électricité supplémentaire. Les résultats démontrent d'excellentes performances même lorsque comparées aux plus récentes technologies. Les résultats passent d'une légère augmentation de la consommation de gaz naturel dans un climat chaud comme Toronto à une importante réduction dans un climat froid comme Edmonton. Ce système permet donc de combler les besoins thermiques d'un bâtiment tout en générant de l'électricité dans des périodes de pointes annuelles et possiblement journalières. Plusieurs études dont notamment l'optimisation du système et le couplage à d'autres types de bâtiment permettrait cependant de mieux évaluer les possibilités complètes de la trigénération. Mots-clés : Trigénération, CCHP, Absorption, Ammoniac-eau, cogénération.

  7. Synthese de champs sonores adaptative

    NASA Astrophysics Data System (ADS)

    Gauthier, Philippe-Aubert

    La reproduction de champs acoustiques est une approche physique au probleme technologique de la spatialisation sonore. Cette these concerne l'aspect physique de la reproduction de champs acoustiques. L'objectif principal est l'amelioration de la reproduction de champs acoustiques par "synthese de champs acoustiques" ("Wave Field Synthesis", WFS), une approche connue, basee sur des hypotheses de champ libre, a l'aide du controle actif par l'ajout de capteurs de l'erreur de reproduction et d'une boucle fermee. Un premier chapitre technique (chapitre 4) expose les resultats d'appreciation objective de la WFS par simulations et mesures experimentales. L'effet indesirable de la salle de reproduction sur les qualites objectives de la WFS fut illustre. Une premiere question de recherche fut ensuite abordee (chapitre 5), a savoir s'il est possible de reproduire des champs progressifs en salle dans un paradigme physique de controle actif: cette possibilite fut prouvee. L'approche technique privilegiee, "synthese de champs adaptative" ("Adaptive Wave Field Synthesis" [AWFS]), fut definie, puis simulee (chapitre 6). Cette approche d'AWFS comporte une originalite en controle actif et en reproduction de champs acoustiques: la fonction cout quadratique representant la minimisation des erreurs de reproduction inclut une regularisation de Tikhonov avec solution a priori qui vient de la WFS. L'etude de l'AWFS a l'aide de la decomposition en valeurs singulieres (chapitre 7) a permis de comprendre les mecanismes propres a l'AWFS. C'est la deuxieme principale originalite de la these. L'algorithme FXLMS (LMS et reference filtree) est modifie pour l'AWFS (chapitre 8). Le decouplage du systeme par decomposition en valeurs singulieres est illustre dans le domaine du traitement de signal et l'AWFS basee sur le controle independant des modes de rayonnement est simulee (chapitre 8). Ce qui constitue la troisieme originalite principale de cette these. Ces simulations du traitement de signal

  8. Realisation d'un detecteur de radioactivite pour un systeme microfluidique

    NASA Astrophysics Data System (ADS)

    Girard Baril, Frederique

    Pour etablir le comportement pharmacocinetique de nouveaux radiotraceurs en imagerie moleculaire, il est necessaire d'approfondir l'analyse realisee a partir d'une image par l'ajout d'une mesure dynamique de la radioactivite dans le sang. L'Universite de Sherbrooke developpe presentement une plateforme microfluidique d'echantillonnage et d'analyse permettant la mesure de la radioactivite du plasma en temps reel. L'objectif du present projet de maitrise etait de realiser le composant optoelectronique responsable de la detection des positrons et de l'integrer a la puce microfluidique. L'option retenue a ete l'utilisation de photodiodes PIN en silicium. Un procede de fabrication, ainsi qu'une serie de photomasques ont ete developpes afin de produire une premiere iteration de prototypes. Les detecteurs ont ete concus de maniere a optimiser leur sensibilite en fonction du type de rayonnement a detecter. En effet, la region de detection doit etre suffisamment epaisse et sensible pour absorber le maximum de particules energetiques. Egalement, il est essentiel de minimiser le courant de fuite en noirceur afin d'obtenir un photocourant directement proportionnel a l'energie des radiations incidentes. Les caracteristiques electriques obtenues avec les premiers detecteurs ont ete demontrees proches des performances de detecteurs commerciaux similaires. De plus, il a ete possible d'integrer un canal microfluidique au substrat contenant les photodiodes et d'en realiser l'encapsulation sans alterer les performances electriques initiales des detecteurs. Une courbe de l'activite radioactive du 18F a ete mesuree, celle-ci se comparant a l'activite theorique associee a ce radioisotope communement utilise en TEP. Enfin, un spectre en energie des emissions radiatives du 18F a ete mesure et compare aux performances de systemes utilisant des photodiodes commerciales. Il a ete demontre que le prototype offrait un rapport signal sur bruit similaire aux systemes bases sur des photodiodes

  9. Case Studies On Recent Stark Broadening Calculations And Stark-B Database Development In The Framework Of The European Project Vamdc (Virtual Atomic And Molecular Data Center)

    NASA Astrophysics Data System (ADS)

    Sahal-Bréchot, S.

    2010-07-01

    Stark broadening theories and calculations have been extensively developed for about 50 years. The theory can now be considered as mature for many applications, especially for accurate spectroscopic diagnostics and modelisation. In astrophysics, with the increasing sensitivity of observations and spectral resolution, in all domains of wavelengths from far UV to infrared, it has become possible to develop realistic models of interiors and atmospheres of stars and interpret their evolution. For hot stars, especially white dwarfs, Stark broadening is the dominant collisional line broadening process. This requires the knowledge of numerous collisional line profiles, especially for very weakly abundant atoms and ions that are used as useful probes for modern spectroscopic diagnostics. Hence, calculations based on a simple but enough accurate and fast method is indispensable for obtaining numerous results. Ab initio quantum calculations are also a useful domain of development, especially for ion emitters. Nowadays, the access to such data via an on line database becomes indispensable. The Virtual Atomic and Molecular Data Centre (VAMDC, http://www.vamdc.eu) is a European Union funded collaboration between groups involved in the generation and use of atomic and molecular data. VAMDC aims to build a secure, documented, flexible and interoperable e-science environment-based interface to existing atomic and molecular data. In this framework, the Stark-B (http://starkb.obspm.fr) database, which is a part of VAMDC, is a collaborative project between the Astronomical Observatory of Belgrade and the Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA). It is a database of calculated widths and shifts of isolated lines of atoms and ions due to electron and ion collisions (i.e. impacts are separated in time). This database is devoted to modelisation and spectroscopic diagnostics of stellar atmospheres and envelopes. In addition, it is relevant to

  10. Inferring sublexical correspondences from sight vocabulary: evidence from 6- and 7-year-olds.

    PubMed

    Stuart, M; Masterson, J; Dixon, M; Quinlan, P

    1999-05-01

    We report an experiment designed to investigate 6-to-7-year-old children's ability to acquire knowledge of sublexical correspondences between print and sound from their reading experience. A computer database containing the printed word vocabulary of children taking part in the experiment was compiled and used to devise stimuli controlled for grapheme-phoneme correspondence (GPC) frequency and rime neighbourhood consistency according to the children's reading experience. Knowledge of GPC rules and rime units was compared by asking children to read aloud three types of nonword varying in regularity of GPC and consistency of rime pronunciation. Results supported the view that children can acquire knowledge of both GPC rules and rime units from their reading experience. GPC rule strength affects the likelihood of a GPC response; rime consistency affects the likelihood of a rime response.

  11. On the Representation of Mandarin Syllable Structure.

    ERIC Educational Resources Information Center

    Kuo, Feng-Lan

    1994-01-01

    This paper argues that Mandarin Chinese has a fixed syllabic represented by the template CGVX, with one slot in the onset and three slots in the rimeprime (as projection of the rime). It claims that the pre-nucleus glide is obligatory, is an independent constituent, and is adjoined to the rime constituent. Extensive evidence for this template is…

  12. Coping Strategies in Reading: Multi-Readers in the Norwegian General Education System

    ERIC Educational Resources Information Center

    Vik, Astrid Kristin; Fellenius, Kerstin

    2007-01-01

    Six primary school-aged braille students were taught to name 4 to 10 braille letters as phonemes and another 4 to 10 braille letters as graphemes (Study 1). They were then taught to name 10 braille words as onset-rimes and another 10 braille words as whole words (Study 2). Instruction in phonemes and onset rimes resulted in fewer trials and a…

  13. Teaching Adults to Read Braille Using Phonological Methods: Single-Case Studies

    ERIC Educational Resources Information Center

    Crawford, Shauna; Elliott, Robert T.

    2009-01-01

    Four women with visual impairments were taught 13 braille letters as phonemes and another 13 braille letters as graphemes and then were taught 10 braille words as onset-rime and another 10 braille words as whole words. Phoneme and onset-rime instruction resulted in faster and more accurate performance. (Contains 1 table and 2 figures.)

  14. Beginning Word Recognition: Benefits of Training by Segmentation and Whole Word Methods.

    ERIC Educational Resources Information Center

    Levy, Betty Ann; Lysynchuk, Linda

    1997-01-01

    Compares effectiveness of four different methods for acquiring initial reading vocabulary--onset plus vowel, rimes, phoneme segmentation and blending, and simple repetition of whole words. Finds that beginning nonreaders acquired the trained words fastest in the onset and rime conditions, and most slowly in the whole word condition. Finds the same…

  15. Learning New Words Affects Nonword Pronunciation in Children

    ERIC Educational Resources Information Center

    Khanna, Maya M.; Cortese, Michael J.; Birchwood, Katharine S.

    2010-01-01

    In two experiments we examined how children's nonword pronunciations are influenced by learning words. In Experiment 1, children pronounced nonwords before and after learning words sharing orthographic rimes with the nonwords. These rimes varied in spelling-to-sound consistency and regularity. Children's nonword pronunciations were more sensitive…

  16. Etude experimentale de l'utilisation des revetements glaciophobes et/ou hydrophobes sur les pales d'eoliennes

    NASA Astrophysics Data System (ADS)

    Adomou, Maryelle C.

    2011-12-01

    Blade icing is a major problem of windmill use in northern climates. At present, the use of anti-icing protection on blades is little used because it is energy intensive and unsafe. An interesting current alternative is the use of ice-shedding coatings because they are proving to be less energy hungry, but their efficiency and durability have yet to be proven in windmills. Since windmills have a special dynamic structure and icing events can be of several types, an understanding of the accretion process on a variety of coatings is necessary to advance general knowledge in this field. To explore this problem, experiments were performed in the refrigerated wind tunnel at the Anti-icing Materials International Laboratory of the Universite du Quebec a Chicoutimi on a static-blade section covered with three commercial ice-shedding coatings chosen using well-defined criteria. Experimental conditions were based on several real extreme icing events. Scaling of the parameters of the icing events gave two air speeds for the wind tunnel (21 and 33m/s), two air temperatures (5 and -20°C) and one humidity level (0.4g/m 3). The experimental runs were carried out on blades covered with the coatings alone and also in combination with an electrothermal deicing system. The efficiency of the apparatus was evaluated by analysing the shape of the ice formed, the energy consumption of each anti-icing and de-icing combination and also by analysing the internal distribution of temperatures in the system. When used as a protective anti-icing system, none of the icephobic coatings was effective in reducing ice accumulation significantly on the blades. However, combined with an electrothermal anti-icing system, these types of coatings proved to be effective. Nevertheless, the power must be high enough to cause runoff. Hydrophobic coatings reduce energy consumption of electric anti-icing systems by about 7% whereas a super hydrophobic coating can reduce energy consumption by more than twice this amount. In de-icing mode and using a super hydrophobic coating, a reduction of 15% was recorded. These power reductions are largely due to the hydrophobic nature of the surfaces.

  17. Introduction à L'Etude de la Médecine Expérimentale. Surgical revolution. Part I.

    PubMed

    Toledo-Pereyra, Luis H

    2009-01-01

    Claude Bernard (1813-1878), the most distinguished French physiologist of the 19th century, made incomparable contributions to the world of medicine of his times and even to ours. Bernard believed in scientific determinism and created the term milieu interieur as a manner to better understand experimental medicine and to present a new way of explaining the function of the living organism. Bernard dealt with innovative developments in the glycogenetic function of the liver, extrahepatic glycogenesis, the role of pancreatic juice in the digestion of fats, vasomotor nervous system discoveries, and other important physiological advances. In 1865, Bernard's most extraordinary book on the philosophy and understanding of experimental medicine appeared. This book represented Bernard's unique contribution to the progress of medical and surgical research. Because of the enormous implications of this work on the advancement of surgical research, which were subsequently applied to clinical surgical practice, we propose that this book created a surgical revolution.

  18. Etude critique de la prise en charge de 159 personnes âgées en consultation de psychiatrie

    PubMed Central

    Ben Thabet, Jihène; Ammar, Yousra; Charfi, Nada; Zouari, Lobna; Zouari, Nasreddine; Gaha, Lotfi; Maalej, Mohamed

    2014-01-01

    Introduction Le phénomène de vieillissement des populations est associé à une augmentation de la prévalence de la morbidité liée à l’âge. La prescription des psychotropes chez le sujet âgé est de plus en plus fréquente dans les institutions, les doses sont de plus en plus élevées, avec un recours fréquent à une poly pharmacothérapie. Nous nous sommes proposé de décrire les conduites thérapeutiques chez le sujet âgé consultant en psychiatrie, en vue de les confronter aux dernières recommandations en la matière. Méthodes L’étude était de type rétrospectif et descriptif. Elle a concerné les sujets âgés d'au moins 60 ans ayant consulté pour la première fois en psychiatrie, au CHU Hédi Chaker à Sfax, en 2010 ou 2011. Résultats Nous avons colligé 159 dossiers. L’âge moyen était de 73 ans. La démence et les troubles de l'humeur étaient les diagnostics les plus fréquents. Sur le plan thérapeutique, une poly thérapie faite d'au moins deux psychotropes de familles différentes a été prescrite pour 55,9%. Chez 60.3% des sujets, le traitement a été prescrit d'emblée à dose complète. Aucun dossier ne faisait état d'une prise en charge psychothérapeutique. Conclusion La prise en charge des malades de notre étude n’était pas conforme aux recommandations, notamment en matière d'association médicamenteuse, de progression des doses et d'association de la psychothérapie à la pharmacothérapie. L'information des médecins et leur sensibilisation aux particularités du sujet âgé contribuerait à optimiser les soins qui leur sont prodigués, y compris en psychiatrie. PMID:25120873

  19. Etude de l’hémogramme dans la drépanocytose homozygote: à propos de 87 patients

    PubMed Central

    Dahmani, Fatima; Benkirane, Souad; Kouzih, Jaafar; Woumki, Aziz; Mamad, Hassan; Masrar, Azlarab

    2016-01-01

    La drépanocytose homozygote, fait partie des hémoglobinopathies les plus fréquentes au Maroc. La drépanocytose est caractérisée par une grande variabilité d’expressions clinique et biologique qui dépendent des facteurs génétiques modulateurs et environnementaux. Elle se manifeste par une anémie régénérative de gravité très variable selon les individus. L’évolution spontanée en l’absence de traitement est le décès précoce. La drépanocytose est caractérisée par une grande variabilité d’expression clinique et biologique qui dépend des facteurs génétiques et environnementaux. Un tableau clinique sévère marqué par une fréquence de transfusion élevée et précoce, des complications infectieuses graves et une mortalité précoce. Un état inflammatoire constant caractérisé par des protéines inflammatoires élevées et état nutritionnel compromis. L’objectif est de déterminer le profil des paramètres hématologiques du drépanocytaire homozygote (SS) marocain au cours des stades stationnaires. Nous avons fait une étude descriptive transversale de 87 patients drépanocytaires (SS). Nous avons réalisé une étude biologique comportant: l’hémogramme avec étude morphologique des globules rouges en coloration MGG et numération automatique des réticulocytes. Les électrophorèses de l’hémoglobine à pH alcalin (8.8) sur gel d’agarose avec intégration densitométrique. L’âge moyen est de 13.22 ans ± 16.36 avec un sex- ratio (H/F) de 1.175 et des extrêmes allant de 0.6 à 36 ans. La répercussion de l’anémie sur le plan biologique, est intense chez 88.5% des patients, 67.8% ont une anémie normocytaire contre 29.9% présentant une microcytose, et 2.3% qui présentaient une macrocytose. Le degré d’anisocytose est lié au degré d’anémie, très évocatrice chez les drépanocytaires homozygotes S/S (95,4%). Une réticulocytose était observée chez nos patients (81,6%) et 52.9% présentaient une thrombocytose. Une leucocytose était observée chez 64.4% des patients et 80.5% ont présenté une neutropénie. Les paramètres de l’hémogramme serviront de base de comparaison lors des crises et permettront d’évaluer l’efficacité de la prise en charge par le clinicien. Les valeurs élevées des globules blancs, plaquettes et CCHM semblent déterminants dans l’expression sévère de la drépanocytose au Maroc. Le profil hématologique du drépanocytaire marocain montre des données semblables à celles rapportées en littérature chez ceux de l’Afrique centrale, avec une leucocytose. Les résultats de notre étude suggèrent que, la drépanocytose est un problème de santé le plus fréquent chez les marocains et que nos résultats sont comparables à ceux décrits dans le syndrome drépanocytaire majeur. PMID:28293356

  20. Contribution à l'Etude des Disques Planétaires et Protoplanétaires Perturbés

    NASA Astrophysics Data System (ADS)

    Charnoz, Sébastien

    2000-11-01

    Nous avons étudié plusieurs aspects dynamiques et photométriques des disques planétaires et protoplanétaires perturbés. Dans la première partie, à l'aide de modèles numériques simples, nous avons étudié l'eacute;volution thermodynamique d'un disque protoplanétaire composé de planétésimaux subissant des collisions physiques inélastiques, au voisinage d'un embryon de planète géante (~ 15 masses terrestres). Dès l'apparition de l'embryon planétaire, un transfert de chaleur se met en place dans le disque, augmentant fortement les vitesses relatives dans ce dernier, sur une région s'étendant sur plusieurs unités astronomiques. L'évolution de ce mécanisme transitoire a été étudiée sur des temps longs (un million d'années) et pour une vaste gamme demasses du perturbateur. C'est un mécanisme générique qui pourrait avoir profondément affecté le processus de formation des planètes, aussi bien telluriques que géantes. Les conséquences sur la formation de la Ceinture d'Astéroïdes sont discutées, ainsi que l'effet possible de la fragmentation des planétésimaux, qui n'a pu être prise en compte dans le modèle numérique. La deuxième partie de cette thèse est une étude photométrique de l'anneau F de Saturne, qui est perturbé par ses deux satellites gardiens. En étudiant un ensemble de plus de 300 images prises au télescope CFH, nous avons mis en évidence la présence de structures étendues, dont l'origine est toujours mal connue. En combinant nos données et celles du télescope spatial, nous avons établi avec précision une nouvelle orbite de l'anneau F, à 140060+/-60 km, soit plus faible de 150 km par rapport à celle déterminée en 1980-81. Cecipourrait être le signe qu'une important restructuration radiale de l'anneau F a dû avoir lieu entre 1980 et 1995.

  1. Integration symplectique et etude dynamique de systemes hamiltoniens: Canalisation d'une particule chargee traversant un cristal

    NASA Astrophysics Data System (ADS)

    Poulin, Robert

    1998-09-01

    Le probleme de canalisation d'une particule chargee traversant un cristal est examine dans un contexte de dynamique hamiltonienne. Nous desirons etudier la stabilite de l'espace des phases engendre par des systemes hamiltoniens a 2 degres de liberte. Ils sont issus d'un modele simple, mais realiste, applique a differentes configurations de canalisation. Afin de realiser cette analyse de stabilite, certains outils doivent etre elabores. Des integrateurs adaptifs et symplectiques, particulierement bien adaptes aux systemes hamiltoniens sont d'abord developpes. En plus d'etre performants, ils permettent la conservation des constantes du mouvement a la precision voulue. De plus, ils ont ete concus pour beneficier directement, sans aucune modification, des derniers developpements dans le domaine de l'integration symplectique. De nouvelles methodes quantitatives, basees sur l'integration symplectique et des simulations de type Monte-Carlo, sont ensuite developpees pour determiner de facon fiable la stabilite des trajectoires. Les resultats montrent que pour les systemes cristallins consideres, s'il y a transition stochastique (espace des phases passe de stable a instable), elle s'effectue de facon graduelle et non abrupte. De plus, une nouvelle forme de representation graphique permet d'examiner avec precision et flexibilite la stabilite de n'importe quel espace des phases.

  2. Etude exploratoire de la commercialisation des nanotechnologies au Canada: L'utilisation de la fouille de donnees de contenu Web

    NASA Astrophysics Data System (ADS)

    Rietsch, Constant

    Companies rely more every day on the Internet, sharing a lot of information to their customers but also their investors and their associates. Most companies share information such as products, services, partnerships, and research and development activities on their website. All this information is much analytical opportunities provided that we can retrieve and interpret. In this context, is the content of a website can be enough to conduct a study on innovation and commercialization? Websites are sources of information available and accessible to everyone. The majority of companies with a website, the coverage of an Internet-based study is an advantage. For our research on the commercialization of nanotechnology in Canada, we recover as many data on websites of Canadian companies listed by various sources as having activities in nanotechnology. From these data we cluster companies according to their nanotechnology field using a list of keywords from scientific papers to estimate the level of advancement of Canadian companies in nanotechnology research. Finally thanks to several indicators of innovation and marketing we describe the current state of nanotechnology in the Canadian industry.

  3. The Role of Women in Foreign-Language Textbooks: A Collection of Essays. Collection d'"Etudes linguistiques" No. 24.

    ERIC Educational Resources Information Center

    Freudenstein, R., Ed.

    Essays that consider the way that women are portrayed in foreign language textbooks are presented. The selected essays were submitted to a competition sponsored by the Federation Internationale des Professeurs de Langues Vivantes, which requested that language teachers assess such concerns as: (1) whether women were described in a stereotyped way;…

  4. Hazard Studies for Solid Propellant Rocket Motors (Etude des Risque pour les Moteurs-Fusees a Propergols Solides)

    DTIC Science & Technology

    1990-09-01

    iss"ues de certaines elutdes ri~certes sut Ic comnportemnent des materiaux 6crgctiques. lii~’Urco-elcrecurqui i6iodie les pliuimrniues (IC r6icion... Resistivity Measurements as Applied to ESI) 108 .6.2 Dielectric Breakdown (dE. dt) III 5.0.3 Dielecttic Constant Measurements 112i 5.6.A The RC...required velocity and to overcome air resistance and gravity. In this context, the term "missile" is limited to self-propelled weapons and restricted to

  5. Etude de la transition tribologique entre le fretting et le meso-fretting pour des materiaux de contact electrique

    NASA Astrophysics Data System (ADS)

    Gagnon, Daniel

    Dans les installations electriques, les contacts sont toujours soumis a des contraintes alternees ou a des micro-deplacements. Il en resulte une corrosion par fretting, phenomene defini comme un type de deterioration de la surface qui se produit lorsque deux materiaux en contact sont soumis a des mouvements microscopiques d'oscillations de tres faible amplitude (0 a 100 mum). Ceci a pour effet de provoquer une degradation de la resistance de contact et une interruption du passage du courant. Ce phenomene a des repercussions considerables sur le plan pratique puisque les micro-deplacements de pieces en contact peuvent etre causes par la dilatation thermique differentielle des metaux, par des vibrations mecaniques, par la relaxation des contraintes ou par l'echauffement des contacts lorsqu'on interrompt et retablit le courant. Nous avons donc dans le cadre de cette these etudie plusieurs aspects du fretting (0--100 mum) et du meso-fretting (100 a 1000 mum) pour differents materiaux de contact electrique. Des travaux experimentaux ont ete realises a partir de deux montages reproduisant divers aspects de la degradation par le fretting. Un premier montage de fretting de type bille-plaque a ete entierement developpe a l'ETS et un second montage, de type fil-plaque a ete utilise en collaboration avec Hydro Quebec IREQ a Varennes. Plusieurs techniques de mesures et d'analyse relevant tant du domaine de la mecanique du contact que de la metallurgie ont ete utilisees pour traiter les resultats. L'influence du courant sur le taux d'usure et la force de friction a ete examinee pour divers materiaux de contacts. Des essais de fatigue thermique et electrique ont ete realises sur divers materiaux et lubrifiants de contact. Il a ete demontre que pour le domaine entre 100 mum et 1000 mum, le taux d'usure n'est pas le meme de 0 a 100 mum et au dela de 1000 mum. La plupart des materiaux evalues montrent un stade de comportement intermediaire dont le debut se situe entre 100 mum et 300 mum. Lorsque l'on substitut le courant CC a un courant CA de 60 Hz ou 400 HZ, la morphologie des debris aux abords de la zone de contact est differente. De plus, lors de la comparaison du vieillissement thermique par conduction versus par chauffage electrique de certains alliages sans plomb, il a ete montre qu'il pourrait y avoir une difference entre les deux en ce qui concerne le taux de croissance des phases intermetalliques.

  6. Etude de la performance de piles a combustible microbiennes et l'effet des materiaux d'electrodes

    NASA Astrophysics Data System (ADS)

    Martin, Edith

    Recent climate change has brought a whole new dimension to the energy field since now we must change our primary source, fossil fuels. The microbial fuel cell (MFC) technology emerged as a result of recent efforts in the development of alternative sources of energy. This project aims to improve the performance maximization of such celsl. It is assumed that the microbial fuel cells' functioning is influenced by the operation conditions as well as the biofilm development and other limitations. It is also appropriate to suppose that the electrode materials also have consequences on either the microorganisms' activity or the electrochemical reaction reactivity. Thus, various operating conditions and configurations are tested to identify the specific effects of these changes on cell performance. Also, the development of the biofilm is extensively studied under various conditions to improve the electrons transfer between the active biofilm and the anode. These experiments and analyses permitted to identify various effects that can improve the microbial fuel cell performance. Thus, the influence of organic load (of glucose and acetate), pH and operating temperature of the fuel cell has been shown and optimal values were determined, leading to a significant increase in the anodic biofilm activity and a decrease of the methanogens activity, the latter reducing the coulombic efficiency by diverting a non-negligible substrate amount for their benefit. Hence, organic loading of 2 to 4 g L-1 day-1, pH between 6,25 and 6,5 as well as high cathode temperature (62 °C) but moderate anode temperature (30 °C) caused a maximum power generation increase to 19,2 W m -3. During the experiments with acetate as substrate, distance between electrodes and fuel cell volume have been reduced, leading to a power density of 92,4 W m-3. All these observations are the subject of the first article presented in this thesis. Since the microbial fuel cell power generation depends on the number of anode-reducing microorganisms populating the biofilm, this relationship was deepened in the second manuscript. This article, which intended to monitor the biofilm development, highlights the influence of external load changing rate during the active biofilm growth. Thus, when the external load is adjusted rapidly to approach the cell internal resistance, electrons exchange is enhanced as well as the proliferation of microorganisms responsible of these electrons generation. By promoting faster anode-reducing microorganisms growth, other species are somewhat disadvantaged and substrate consumption is primarily involved in the electricity production rather than any other unwanted products (eg.: methane). This article also demonstrates the influence of the biofilm development level on the diffusion limitation of the anodic reaction, a limitation that becomes more pronounced as the biofilm grows. The third article clarifies the diffusion limitation of the charge transfer at the anode. Therefore, the organic load variation of acetate in microbial fuel cells with carbon felt (3D) and carbon paper (2D) anodes as well as the electrolyte conductivity decrease has targeted protons diffusion out of the biofilm as the current generation limitation. In addition, a secondary electrochemical reaction has been identified at the anode, creating an electrode resistance increase and thereby a slight power output decrease. Finally, multiple electrochemical analyses helped to establish with certainty that the electron transfer mechanism carried out by anode-reducing microorganisms is by direct contact with the anode via microorganisms themselves or the conductive biofilm matrix, cytochromes being responsible for the electrons transport in both cases. The last manuscript deals with new cathode materials (carbon, Mn 2O3 and Fe2O3) evaluation in comparison to a platinum cathode. These materials were chosen for their potential to stimulate the proliferation of microorganisms capable of influencing cathode activity in order to obtain a biocathode; however, this phenomenon has not been verified. (Abstract shortened by UMI.)

  7. Mutations des roles techniques et formation. Etude documentaire (Changes in the Roles and Education of Technicians. Documentary Study).

    ERIC Educational Resources Information Center

    Pinard, Helene

    Drawing from research conducted in 1990-91, this report examines trends affecting the future work of technicians in Quebec, their pre-employment education, and the link between college and work. Part 1 focuses on aspects of the economic, technological, and social environment that will influence the future role of technicians. Economic concerns…

  8. Theoretical and Experimental Methods in Hypersonic Flows (Les Methodes Theoriques et Experimentales pour l’Etude Des Ecoulements Hypersoniques)

    DTIC Science & Technology

    1993-04-01

    figure 5 presente une comparaison entre la ripartition de avantages qiac l’on petit tirer d’une recompression naturelle nombre de Mach stir l’axe de...pressions paridtales ont Wt d’Electrons [1111. La figure 7 illustre cos techniques. 11 s’agit mosur~es 118J A ]’aide do capteurs diffdrentiels A self...Lors de visualisations r~alis~es autour d’un barreau cylindrique do ces essais, lea capteurs Etaient situ~s dana le caisson dispose transversalement

  9. Etude des Abondances de MG et de fe dans la Composante Stellaire des Disques des Galaxies Spirales

    NASA Astrophysics Data System (ADS)

    Beauchamp, Dominique

    Je presente ici une technique d'observation par imagerie des disques stellaires des galaxies spirales. Je tente, a l'aide d'un modele evolutif multiphase, de determiner les abondances de fer et de magnesium dans les disques. Dans ce but, je mesure les indices Mg2 et Fe5270 du systeme de Lick. Ces elements representent un choix judicieux d'indicateurs car ils sont formes par des supernovae de deux types differents ayant des durees de vie differentes. Le rapport d'abondances de ces deux elements est un indicateur du taux de formation des populations stellaires. Je decris, en premier lieu, les observations, la technique de mesure, ainsi que son application. J'analyse ensuite les indices mesures. A partir du modele multiphase, j'explore differents parametres physiques des spirales comme le taux de formation stellaire, l'evolution des abondances, les effets possibles de la presence de la barre, etc.

  10. Etude de solutions pour la mise en oeuvre d'une antenne a reflecteur bi-grille en polarisation circulaire

    NASA Astrophysics Data System (ADS)

    Joyal, Marc-Andre

    Dual-gridded reflector (DGR) antennas are widely used on satellites. They consist of a cascade of two parabolic grids operating in orthogonal linear polarizations, each one having its own feed. Therefore, DGRs are actually two antennas in one structure, so they use less space on the satellite. Moreover, they provide excellent isolation between adjacent coverage areas. The disadvantage with these DGRs is that they work only in linear polarization (vertical and horizontal). In this thesis, two different solutions to design a circularly polarized (right and left hand circular polarizations) DGR are explored. The first one consists in the use of circular polarizers that are fixed on a conventional DGR. Those polarizers are surfaces that make the conversion between linear and circular polarizations. The other solution uses circular polarization selective surfaces (CPSSs) as reflectors on the DGR instead of the orthogonal grids. These CPSSs are structures that are transparent to one sense of circular polarization (say right hand circular polarization for instance), but that reflect the other sense (left hand circular polarization). The major part of this work is based on the first solution. A new circular polarizer design method is proposed. It allows a greater flexibility in the polarizer design than existing designs. The proposed technique is also modified in order to implement polarizers optimized for an oblique incidence, which is required for DGR applications. The second solution using CPSSs is only briefly explored. A new type of CPSS, implemented with a cascade of circular and linear polarizers, is proposed. This cascade CPSS has shown a broader bandwidth than those obtained with the resonant structures known so far. Also, the limitations of CPSSs are identified as to their use on DGRs. Finally, as a proof of concept, two simple prototypes of circularly polarized DGRs are presented. The first design is implemented with a circular polarizer and a metallic grid attached to a small reflector. The second prototype is similar, but the planar grid is replaced by a reflectarray that plays the same role, but increases the gain in the direction of the main beam. The satellite industry requirements between 18-20 GHz are respected with this latter implementation, but only for a very low variation in the elevation angle.

  11. Etude des proprietes mecaniques statiques et dynamiques de pieces d'acier elaborees par metallurgie des poudres

    NASA Astrophysics Data System (ADS)

    Bernier, Fabrice

    The main objective of this thesis ais to gain a better understanding of the effects of processing variables on the porosity and microstructure of powder metallurgy (P/M) steel and their effect on mechanical properties, both static and dynamic. The effects of processing variables on porosity and microstructure were evaluated by advanced microstructural characterization using both optical and electron microscopies. Then the impacts of porosity and microstructure on both static and dynamic properties were measured. Static mechanical properties were characterized by hardness measurements and by tensile tests while fatigue testing was used for evaluating dynamic properties. Fractographic observations were made on tensile and fatigue fracture samples to correlate the microstructural features to the mechanical performance of P/M steels. The experimental work covered in this Ph.D. thesis enables to further understand the mechanisms by which process variables affect the microstructure and the mechanical properties of samples. In the first paper, the effect of prealloying MnS up to 1.0 wt pct on the microstructural features of non-metallic inclusions and their impact on tensile and fatigue properties of a 7.0 g/cm3 P/M steel (Fe-2.0Cu-0.7C) have been investigated. As the MnS content increases, larger, more irregular and more closely spaced inclusions are obtained. Whilst no significant impact on both static and dynamic properties was observed when prealloying up to 0.65 wt pct MnS, a decrease of more than 15 pct of the ultimate tensile strength and of the endurance limit was found when the MnS content reaches 1.0 wt pct. The decrease in the ultimate tensile strength is attributed to a lower ductility of the sinternecks, as void initiation and void growth were promoted at lower stress levels by larger inclusions. The larger size of the MnS particles and the lower mean free path between non-metallic inclusions also favor microcrack initiation and their coalescence into cracks, leading to premature fatigue fracture. In the second paper, the improvement of performance that can be achieved by copper infiltration was quantified. Tensile and fatigue properties of a Fe-2.0Cu-0.7C PM steel were compared to the same alloy infiltrated with 8 wt-% copper. Microstructural characterization, using optical and electron microscopies, was carried out to understand the effect of copper infiltration on mechanical properties. Copper infiltration improves the ultimate tensile strength by 40% by increasing the load bearing section, decreasing the stress concentrations associated to open porosity and increasing the hardness of the steel matrix. Fractographic observations show the evidence of stress transmission from the sinternecks to the steel particles due to infiltrated copper. The beneficial effect of copper infiltration is less pronounced for fatigue properties as the endurance limit is increased by only 10%. This lower improvement is explained by crack initiation at the copper/steel matrix interface. In the last paper, the microstructural characterization of nickel rich areas and their influence on the endurance limit of a P/M steel was investigated. The addition of nickel powder to a P/M steel increases hardenability, enabling the formation of martensite directly after the sintering process. However, the slow diffusion rate of nickel into iron leads to the formation of nickel rich areas (NRA). Two steel alloys were studied, the first one is a Fe-6.4Ni-0.7Mo-0.7C with standard size nickel powder additions and the second one is a Fe-2.4-0.7Mo-0.7C where a finer size nickel powder was added. The influence of the size of the nickel powder used on hardenability and on the presence of NRA has been investigated by optical microscopy. A complete identification of the microstructural constituents and the effect of nickel concentration on their presence were achieved using X-ray energy dispersive spectrometry and electron diffraction in the transmission electron microscope. Results obtained by these techniques show the presence of austenite and martensite. Fatigue tests were carried out on P/M steel parts with and without austenitic areas to study their impact on the endurance limit. The analysis of the results showed that these areas are not a governing factor for the endurance limit of sintered steels. (Abstract shortened by UMI.)

  12. Etude de la microstructure d'un acier 316 titane apres vieillissement et apres irradiation aux neutrons

    NASA Astrophysics Data System (ADS)

    Brun, G.; Le Naour, J.; Vouillon, M.

    1981-10-01

    La précipitation qui se produit lors de vieillissements de longue durée entre 450 et 700°C dans un acier 316 Ti soit hypertrempé soit écroui, a été étudiée en couplant les techniques de microscopic électronique et de microanalyse X. Pour les cas expérimentaux étudiés, les résultats obtenus montrent que la composition des carbures M 23C 6 et des phases σ, Laves et χ est peu sensible aux conditions de vieillissement et dépend également peu de l'état structural initial. Leur teneur en éléments principaux de l'alliage est d'ailleurs voisine de celle des phases précipitées dans l'acier non stabilisé. Excepté les carbures de type M 6C, toutes ces phases ont une teneur en nickel inférieure à celle de la matrice. Les premiers rérultats obtenus sur des matériaux irradiés aux neutrons montrent que la précipitation sous flux est différente de celle qui se produit dans l'acier vieilli. Les phases γ' et G ainsi que les carbures riches en nickel ont été observés. L'attention a été attirée sur le fait qu'il n'y a pas de corrélation simple entre la vitesse de gonflement et la teneuer résiduelle en nickel de la matrice.

  13. Etude de la variabilite climatique des hautes latitudes nord, derivee d'observations satellites micro-ondes

    NASA Astrophysics Data System (ADS)

    Mialon, Arnaud

    Observing sub-polar ecosystems is important as they are suspected to change significantly in response to the expected increase in temperature for the next decades. To bypass the lack of meteorological stations in the Northern High Latitudes, remote sensing is an interesting alternative tool, covering almost the entire area. This project deals with the development of a method to derive surface parameters (>50°N) from satellite data. For this study, brightness temperature data acquired by the SSM/I (Special Sensor Microwave Imager) in the microwave spectrum are used because they are independent of solar radiation and weakly influenced by the atmosphere. Methods used are based on brightness temperatures measured at 19 and 37 GHz, which allow to derive three geophysical parameters related to climate variability: daily maps of snowcover between 1988 and 2002; a water surface extent (open water, small lakes, reservoirs, wetlands associated with low vegetation); a temperature characterizing the surface and the air above the ground. A method to normalize the temperature is presented to overcome the variation of the time of measurement. It leads to hourly series of temperature, This allows to study climate indicators such as the annual sum of positive degree days. Trends confirm observed climate evolution: increase of surface temperature (+0.8 +/- 0.4°C for Canada/Alaska between 1992 and 2002), decrease in snow extent cover. These original databases could also be useful for validation of regional climate model. (Abstract shortened by UMI.)

  14. Etude de production et de caracterisation de biocharbons de panic erige (Panicum virgatum L.) obtenus par pyrolyse

    NASA Astrophysics Data System (ADS)

    Pilon, Guillaume

    This research aimed at the production of biomass char under pyrolytic conditions, targeting biochar as soil amendment, while also considering its application as biocoal, either for bioenergy or subsequent upgrading. The production of biomass char was performed using two bench-scale, batch-type, fixed-bed reactors, each with an operating capacity of 1 and 25 gw.b. /batch, respectively. Switchgrass (Panicum virgatum) has been used for the tests. Production conditions studied implied temperatures of 300, 400 and 500 °C with short residence times (2.5 and 5 min). As well, the effect of using CO2 as vector gas has been compared to a common inert environment of N2. The effects of the previously mentioned parameters were correlated with some important physicochemical characteristics of biomass char. Analyses were also performed on complementary pyrolytic products (bio-oil and gas). The biomass char extraction was performed using a Soxhlet and dichloromethane was used as extracting solvent. The extracts were then characterized by GC-MS thus allowing the identification of several compounds. Specific pyrolysis conditions used at 300 °C - N2 with the 1 g/batch reactor, such as high heating rates as well as high convection conditions, presented advantegeous biomass char yields and properties, and, possible torrefaction process productivity improvement (in comparison to reported literature, such as Gilbert et al. [2009]). The char extracts as well as the bio-oils analysis (also performed using GC-MS), all generated from the 25 g/batch reactor, showed major differences among the compounds obtained from the CO2 and N2 environments, respectively. Several compounds observed in the char extracts appeared less concentrated in the CO2 environment vs N2, for the same reaction temperatures. As an example, at 400 °C, furfural was found only in char extracts from N2 environment as compared to the CO2 environment. Among all studied conditions (for both reactors), only naphthalene and naphthalene derivatives constituted the PAHs content, which was only detected for the chars produced at 500 °C. The use of CO2 as pyrolysis vector gas led to a significant difference for every temperature conditions studied for the biomass char as well as for the liquid and gas products. At 300 °C, in CO 2 environment, it is possible to observe a bio-oil production significantly lower than within a N2 environment (18.0 vs 24.6 %; CO2 vs N2 for P<0.002), a result consistent with the biomass char volatile content that was shown to be significantly higher under the same conditions (0.29 vs 0.35 gchar volatiles content/graw biomass; P=0.1). In addition, at 500 °C, the char ash content was observed to be significantly lower in CO 2 than in N2 (P<0.06). Keywords: Pyrolysis, torrefaction, char, biochar, biocoal, CO 2, Soxhlet extractions, characterization.

  15. Elaboration du Ge mesoporeux et etude de ses proprietes physico-chimiques en vue d'applications photovoltaiques

    NASA Astrophysics Data System (ADS)

    Tutashkonko, Sergii

    Le sujet de cette these porte sur l'elaboration du nouveau nanomateriau par la gravure electrochimique bipolaire (BEE) --- le Ge mesoporeux et sur l'analyse de ses proprietes physico-chimiques en vue de son utilisation dans des applications photovoltaiques. La formation du Ge mesoporeux par gravure electrochimique a ete precedemment rapportee dans la litterature. Cependant, le verrou technologique important des procedes de fabrication existants consistait a obtenir des couches epaisses (superieure a 500 nm) du Ge mesoporeux a la morphologie parfaitement controlee. En effet, la caracterisation physico-chimique des couches minces est beaucoup plus compliquee et le nombre de leurs applications possibles est fortement limite. Nous avons developpe un modele electrochimique qui decrit les mecanismes principaux de formation des pores ce qui nous a permis de realiser des structures epaisses du Ge mesoporeux (jusqu'au 10 mum) ayant la porosite ajustable dans une large gamme de 15% a 60%. En plus, la formation des nanostructures poreuses aux morphologies variables et bien controlees est desormais devenue possible. Enfin, la maitrise de tous ces parametres a ouvert la voie extremement prometteuse vers la realisation des structures poreuses a multi-couches a base de Ge pour des nombreuses applications innovantes et multidisciplinaires grace a la flexibilite technologique actuelle atteinte. En particulier, dans le cadre de cette these, les couches du Ge mesoporeux ont ete optimisees dans le but de realiser le procede de transfert de couches minces d'une cellule solaire a triple jonctions via une couche sacrificielle en Ge poreux. Mots-cles : Germanium meso-poreux, Gravure electrochimique bipolaire, Electrochimie des semi-conducteurs, Report des couches minces, Cellule photovoltaique

  16. Etude des defauts microscopiques et des proprietes optiques, electroniques et magnetiques du compose neodyme cerium oxyde de cuivre

    NASA Astrophysics Data System (ADS)

    Richard, Pierre

    La presente these, qui combine des mesures de diffusion Raman, de transmission infrarouge, de conductivite hyperfrequence et d'interferometrie ultrasonore sur les composes Nd 2-xCexCuO 4, traite des defauts d'oxygene, ainsi que des proprietes optiques, electroniques et magnetiques de ces materiaux. Les resultats experimentaux obtenus sont correles avec plusieurs donnees experimentales disponibles dans la litterature. D'abord, la caracterisation des modes Raman et des niveaux d'energie de champ cristallin de l'ion Nd3+ au moyen de techniques optiques, en fonction du dopage en cerium et du contenu en oxygene, permettent de conclure a la presence de defauts lies a une non-stoechiometrie en oxygene dans ces composes. En effet, des excitations de champ cristallin assignees a des ions Nd3+ en sites irreguliers sont observees, en plus des bandes d'absorption associees aux ions Nd3+ en site regulier, dans les spectres correspondant aux multiplets 4I11/2, 4I13/2 et 4I 15/2 de l'ion Nd3+. Les resultats experimentaux indiquent que, contrairement a la croyance largement repandue, les oxygenes apicaux, bien que presents dans les echantillons dopes, ne sont pas enleves lors du processus de reduction des echantillons necessaire pour faire apparaitre la supraconductivite dans cette famille de cuprates. Au contraire, des lacunes d'oxygene, dont le type varie en fonction du dopage, sont creees lors de ce processus. En particulier, il est montre dans ce travail que la reduction des echantillons dopes de maniere optimale conduit a la creation de lacunes d'oxygene dans les plans CuO2. Les consequences de telles lacunes sont largement discutees. En outre, il est suggere que de telles lacunes sont responsables de la perte de l'ordre antiferromagnetique a longue portee des ions Cu2+. Finalement, l'interaction d'echange anisotrope Nd3+-Cu 2+ dans le compose nondope est caracterisee au moyen de la transmission infrarouge sous champ magnetique. L'eclatement des doublets de Kramers mesure experimentalement est compare, en fonction de l'intensite et de l'orientation du champ magnetique externe, a des calculs d'effet Zeeman. Alors, que les calculs d'effet Zeeman ne coincident pas avec les donnees experimentales pour un champ applique perpendiculairement aux plans CuO 2, ceux-ci sont en accord avec les resultats de transmission infrarouge pour des champs superieurs a 4 T appliques parallelement a ces plans, indiquant une suppression apparente de l'interaction d'echange anisotrope Nd3+-Cu 2+ dans de telles conditions. (Abstract shortened by UMI.)

  17. Etude du diagramme ternaire CuInSe 2ZnSeIn 2Se 3

    NASA Astrophysics Data System (ADS)

    Chippaux, Daniel; Deschanvres, Alfred

    1982-11-01

    The system CuInSe 2ZnSeIn 2Se 3 has been investigated. A large domain of thiogallate-type compounds was found with a number of cation vacancies less or equal to that of ZnIn 2Se 4 compound. A study with a least-squares method was performed on the experimental parameters a and c and relations with the compositions are given. The blende-structure model with cation vacancies was used for evaluation of the vacancy radius [ r1 = (0.97 ± 0.05) Å] in the thiogallate compounds.

  18. Etude de la transmission sonore a travers un protecteur de type "coquilles" : modelisation numerique et validation experimentale

    NASA Astrophysics Data System (ADS)

    Boyer, Sylvain

    On estime que sur les 3,7 millions des travailleurs au Quebec, plus de 500 000 sont exposes quotidiennement a des niveaux de bruits pouvant causer des lesions de l'appareil auditif. Lorsqu'il n'est pas possible de diminuer le niveau de bruit environnant, en modifiant les sources de bruits, ou en limitant la propagation du son, le port de protecteurs auditifs individualises, telles que les coquilles, demeure l'ultime solution. Bien que vue comme une solution a court terme, elle est communement employee, du fait de son caractere peu dispendieux, de sa facilite d'implantation et de son adaptabilite a la plupart des operations en environnement bruyant. Cependant les protecteurs auditifs peuvent etre a la fois inadaptes aux travailleurs et a leur environnement et inconfortables ce qui limite leur temps de port, reduisant leur protection effective. Afin de palier a ces difficultes, un projet de recherche sur la protection auditive intitule : " Developpement d'outils et de methodes pour ameliorer et mieux evaluer la protection auditive individuelle des travailleur ", a ete mis sur pied en 2010, associant l'Ecole de technologie superieure (ETS) et l'Institut de recherche Robert-Sauve en sante et en securite du travail (IRSST). S'inscrivant dans ce programme de recherche, le present travail de doctorat s'interesse specifiquement a la protection auditive au moyen de protecteurs auditifs " passifs " de type coquille, dont l'usage presente trois problematiques specifiques presentees dans les paragraphes suivants. La premiere problematique specifique concerne l'inconfort cause par exemple par la pression statique induite par la force de serrage de l'arceau, qui peut reduire le temps de port recommande pour limiter l'exposition au bruit. Il convient alors de pouvoir donner a l'utilisateur un protecteur confortable, adapte a son environnement de travail et a son activite. La seconde problematique specifique est l'evaluation de la protection reelle apportee par le protecteur. La methode des seuils auditifs REAT (Real Ear Attenuation Threshold) aussi vu comme un "golden standard" est utilise pour quantifier la reduction du bruit mais surestime generalement la performance des protecteurs. Les techniques de mesure terrains, telles que la F-MIRE (Field Measurement in Real Ear) peuvent etre a l'avenir de meilleurs outils pour evaluer l'attenuation individuelle. Si ces techniques existent pour des bouchons d'oreilles, elles doivent etre adaptees et ameliorees pour le cas des coquilles, en determinant l'emplacement optimal des capteurs acoustiques et les facteurs de compensation individuels qui lient la mesure microphonique a la mesure qui aurait ete prise au tympan. La troisieme problematique specifique est l'optimisation de l'attenuation des coquilles pour les adapter a l'individu et a son environnement de travail. En effet, le design des coquilles est generalement base sur des concepts empiriques et des methodes essais/erreurs sur des prototypes. La piste des outils predictifs a ete tres peu etudiee jusqu'a present et meriterait d'etre approfondie. L'utilisation du prototypage virtuel, permettrait a la fois d'optimiser le design avant production, d'accelerer la phase de developpement produit et d'en reduire les couts. L'objectif general de cette these est de repondre a ces differentes problematiques par le developpement d'un modele de l'attenuation sonore d'un protecteur auditif de type coquille. A cause de la complexite de la geometrie de ces protecteurs, la methode principale de modelisation retenue a priori est la methode des elements finis (FEM). Pour atteindre cet objectif general, trois objectifs specifiques ont ete etablis et sont presentes dans les trois paragraphes suivants. (Abstract shortened by ProQuest.).

  19. Contributions de la geographie et de la modelisation predictive a une etude de potentiel archeologique prehistorique en Gaspesie

    NASA Astrophysics Data System (ADS)

    Desrosiers, Marc

    La Gaspésie, région péninsulaire à l'extrême est du Québec, possède un héritage archéologique préhistorique riche qui s'étend de 9 000 ans jusqu'à 450 ans avant aujourd'hui. L'archéologie a livré de nombreux sites préhistoriques dans la région, surtout dans le nord de la péninsule, un constat en partie attribuable à la présence de sources de matières premières lithiques, d'axes de circulation potentielles, mais aussi à la répartition spatiale inégale des efforts de recherche. L'étude du potentiel archéologique préhistorique gaspésien, c'est la première étape de la démarche archéologique, est donc nécessaire pour orienter les travaux futurs dans cette région. Trois secteurs représentatifs de la Gaspésie ont été étudiés pour développer une nouvelle approche d'étude de potentiel : Sainte-Anne-des-Monts, le lac Sainte-Anne et New Richmond. Ensemble, ces secteurs s'étirent au travers de la péninsule sur un axe nord-sud et correspondent à un possible axe de circulation préhistorique. L'évaluation du potentiel archéologique de ces aires d'étude dépend notamment de contexte géographique gaspésien. Celui-ci est complexe, particulièrement depuis la déglaciation qui a engendré une succession de transformations du paysage. Les variations du niveau marin relatif, le passage de la toundra à un milieu forestier et d'autres changements environnementaux ont conditionné la façon dont les populations préhistoriques se sont adaptées au territoire. L'étude de potentiel dépend également des connaissances archéologiques existantes pour la région, car elles conditionnent la sélection de variables environnementales représentatives des sites connus. À partir de la confrontation des données géographiques et archéologiques, nous avons proposé des schèmes d'établissement pour les périodes chronoculturelles de la préhistoire gaspésienne. Ces patrons informationnels permettent d'illustrer la façon dont les populations préhistoriques occupaient le territoire gaspésien. C'est en appliquant ces schèmes d'établissement dans un SIG (Système d'Information Géographique) qu'il est alors possible de modéliser l'occupation potentielle du territoire au cours des périodes de la préhistoire gaspésienne. Les résultats de la modélisation sont prometteurs car les sites archéologiques connus dans le secteur de Sainte-Anne-des-Monts correspondent aux secteurs à potentiel élevé proposés par la modélisation, bien qu'une validation géomorphologique de la modélisation soit nécessaire à une étape ultérieure. Les deux autres secteurs ne présentaient pas de sites archéologiques datés qui permettaient de valider la modélisation à ces endroits. L'outil proposé est d'autant plus intéressant qu'il permet d'étudier rapidement de vastes territoires au potentiel archéologique mal évalué, comme c'est le cas de la Gaspésie.

  20. Mathematics Comparison Study Companion Database = Base de Donnees Accompagnant L'Etude Comparative Portant sur les Mathematiques.

    ERIC Educational Resources Information Center

    Alberta Dept. of Education, Edmonton. Curriculum Standards Branch.

    This companion database to the Mathematics Comparison Study consists of the entire set of all the general and specific outcomes that were referenced in the report. The database is being released in response to requests made during the review of the draft document in June, 1999, for more information. In the main report, only codings for the general…

  1. Etude des mecanismes de formation des microstructures lors du brasage isotherme de superalliages a base de nickel

    NASA Astrophysics Data System (ADS)

    Ruiz-Vargas, Jose

    This thesis reports theoretical and experimental investigations carried out to understand the mechanisms of microstructure formation during isothermal brazing, produced by brazing Inconel 625 and MC2 nickel-based superalloys with filler metal BNi-2. Firstly, studies were made on pure Ni to interpret microstructure's formation with simplified alloy chemistry. Microstructure formation have been studied when varying time at constant temperature (isothermal kinetics), but also when varying temperature for constant hold time (isochronal kinetics). The chemical composition and crystallography of the present phases have been identified, with the following results : (i) the fraction of dissolved base metal has been found proportional to the initial thickness of the brazing alloy, so that the composition of the liquid remains homogeneous with a precise initial equilibrium composition during the whole brazing process, (ii) the melting of the joint occurs in two steps : at lower temperature, it involves only partially melting, and boron diffusion in pure Ni leads to the precipitation of fine Ni3B borides at the interface ; in a second stage, at higher temperature, melting is complete and thermodynamic equilibrium requires significant dissolution of nickel, which also involves the dissolution of part of borides already formed. Secondly, nickel plating technique was used on Inconel 625 nickel-based superalloy. A thin layer of Ni with varying thickness, has been electrodeposited to observe the gradual dissolution of Inconel and microstructural features formation due to the presence of superalloy alloying elements. It has been observed that the nickel coating does not prevent precipitation in the base metal as boron diffuse rapidly through the coating width. In the intermediate nickel plating width, fragile precipitates of nickel borides have been observed, because the contribution of Inconel alloying elements to the melt was very limited. In absence of nickel plating on the superalloy, the formation of Nb and Cr-Mo borides phase has been observed. Efforts have been made to evaluate the accuracy of Boron measurement by energy dispersion X-ray spectroscopy (EDS) in the MC2 superalloy and BNi-2 filler metal. The most accurate method to quantify Boron using EDS is by composition difference. A precision of 5 at.% has been reached when using optimized data acquisition and post processing schemes. Ultimately, Electron Backscatter Diffraction (EBSD) combined with localized EDS analysis has been proven invaluable in conclusively identifying micrometer sized boride precipitates ; thus further improving the characterization of brazed Ni-based superalloys.

  2. Initiating Franco-American Studies: A Handbook for Teachers = Manuel du professeur pour introduire les etudes Franco-Americaines.

    ERIC Educational Resources Information Center

    Freeman, Stanley L., Jr.; Pelletier, Raymond J.

    This five-chapter handbook is designed for use by teachers in elementary and secondary schools and adult education. Its purpose is to achieve more widespread awareness and understanding of the Franco-American presence in New England by offering teaching plans and strategies for incorporating materials into the existing humanities curriculum. It…

  3. Etude séro-épidémiologique de la leishmaniose canine au centre du Maroc

    PubMed Central

    Fellah, Hajiba; Doughmi, Oursula; Maniar, Saâd; Lalami, Abdelhakim El Ouali

    2014-01-01

    Dans le monde, la leishmaniose viscérale humaine est connue pour avoir comme principale source d'infection les Canidés domestiques et sauvages. Au centre du Maroc, les données épidémiologiques, cliniques et parasitologiques sur la leishmaniose canine, sont quasiment inexistantes. Ce travail traite une étude prospective au cours de laquelle 61 sérums canins ont été analysés par un test rapide et par l'immunofluorescence indirecte. La sensibilité du test rapide par rapport à celle de l'immunofluorescence indirecte (IFI) est de 33,33%. La fréquence de la maladie chez les chiens s’élève à 9,83% (Test Rapide) et 24,59% (IFI). 73,33% des cas canins positifs à la sérologie sont asymptomatiques. Ce sont les jeunes chiens de moins de 5 ans qui sont les plus fréquemment atteints avec une sensibilité de la race Berger Allmand à l'infection. Cette étude a permis de mettre en évidence la présence de chiens leishmaniens (15 chiens séropositifs parmi 61) et de prouver l'existence du réservoir canin. Une stratégie de prévention active doit être mise en place. PMID:25852791

  4. Etude onomasiologique k'un vocabulaire politique: le vocabulaire europeen (Onomastic Study of a Political Vocabulary: The European Vocabulary)

    ERIC Educational Resources Information Center

    Schumacher, Nestor

    1974-01-01

    This article studies the linguistic phenomena that accompany the development of a common French-German political terminology. Important stages are the coexistence of similar terms, fixation of terms, appearance of key words, and polarization of terms. (Text is in French) (AM)

  5. Etude vibrationnelle d'aluminates et de gallates de terres rares—II. Gallates de structure pérovskite

    NASA Astrophysics Data System (ADS)

    Saine, M. C.; Husson, E.; Brusset, H.

    The i.r. spectra of some gallates LnGaO 3 (Ln = La, Pr, Nd) with perovskite structure and the Raman spectrum of NdGaO 3 are presented and analysed. The force field, calculated for the three compounds, is stronger than for homologous aluminates. The GaO bonds which are parallel to the C2 axis are stronger than the others, thus showing the existence of a privileged direction. This effect decreases from La to Nd compounds.

  6. Etude vibrationnelle d'aluminates et de gallates de terres rares—III. Aluminates et gallates de structure grenat

    NASA Astrophysics Data System (ADS)

    Saine, M. C.; Husson, E.; Brusset, H.; de, A. Cerez

    The i.r. absorption and Raman scattering spectra of some aluminium and gallium garnets have been studied. They show a stronger force field in the aluminates than in the gallates and the influence of the ionic radius of the Ln 3+ cation on the frequencies of the aluminium—oxygen or gallium—oxygen network. The study of the system Er 3Ga 5O 12-Er 3Al 5O 12 permitted us to propose an assignment of the different ranges of frequencies and to point out that the tetrahedra vibrations are higher than the octahedra ones. The i.r. spectrum of the perovskite NdGaO 3 is compared to the garnet Nd 3GasO 12 one.

  7. Etude vibrationnelle d'aluminates et de gallates de terres rares—IV. Aluminates de samarium et d'europium

    NASA Astrophysics Data System (ADS)

    Saine, M. C.; Husson, E.

    In order to complete our studies on rare earth aluminates and gallates of perovskite structure, we have calculated a force field for orthorhombic SmAlO 3 and EuAlO 3. This force field is anisotropic with regard to the ab plane of the structure and is slightly weaker than the force field of the rhombohedral aluminates LaAlO 3 or NdAlO 3.

  8. Etude vibrationnelle d'aluminates et de gallates de terres rares—I. Alluminates de structure pérovskite

    NASA Astrophysics Data System (ADS)

    Saine, M. C.; Husson, E.; Brusset, H.; Cerez, A.

    The i.r. spectra of some aluminates of rhomboedral and orthorhombic perovskite types are presented and analysed. The complete vibrational analysis of NdAlO 3 is presented and a force field is proposed for this type of compounds; the potential energy distribution is given and the normal modes are drawn using ORTEP program.

  9. Sur le ternaire Tl sbnd Ge sbnd Te: Etude structurale de la phase Tl 2GeTe 5

    NASA Astrophysics Data System (ADS)

    Toure, Abdoulaye Abba; Kra, Gabrielle; Eholie, Rose; Olivier-Fourcade, Josette; Jumas, Jean-Claude; Maurin, Maurice

    1990-02-01

    Tl 2GeTe 5 is orthorhombic, space group Cmmm, with cell dimensions a = 11.657 (5), b = 11.657 (5), c = 14.917 (5), AandZ = 8. The crystal structure was determined by means of direct methods based on three-dimensional X-ray data. Atomic parameters were refined by a least-squares method to a final R value of 0.077 (507 observed reflexions). The structure can be described in terms of layers parallel to the [001] plane and characterized by (Ge 2Te 6) 4- anions and Te 4 clusters.

  10. Etude de la physico-chime d'un magnetoplasma de chlore pour la gravure sous-micrometrique

    NASA Astrophysics Data System (ADS)

    Pauna, Olivier Daniel

    The aim of this thesis is to achieve a better understanding of physical and chemical phenomena occurring in a high-density plasma designed for sub-micron etching of thin films. The plasma is produced in chlorine by means of an electromagnetic surface wave and it can be confined by a uniform static magnetic field. The flexibility offered by the reactor in terms of operating conditions makes possible a parametric study of the influence of the magnetic confinement on the plasma characteristics. Thus, we have examined the plasma properties by means of several diagnostics techniques, including electrostatic probes, laser photodetachment of negative ions, ion acoustic wave propagation and optical emission spectroscopy. First, we investigated the influence of the operating conditions on the spatial properties of the plasma; this includes electric characteristics (electrons, positive and negative ions) as well as chemical characteristics (reactive neutrals). Second, we studied the impact of the reactor aspect ratio (i.e. reactor length/radius ratio) on both electrical and chemical characteristics. Together with these experimental studies, we have developed a bidimensional fluid model, by solving self-consistently the first two moments of Bolzmann equation and Poisson's equation. Using a semi-implicit scheme, it was possible to maintain a short computation time and to use this model to investigate a diffusion plasma in an electropositive gas. We were thus able to estimate the value of the diffusion coefficient in the direction perpendicular to the magnetic field. The results thus obtained are in good qualitative agreement with the diffusion coefficient proposed by Liebermann and Lichtenberg.

  11. Etude d'integration fonctionnelle du cycle de developpement des produits et des communautes de pratique virtuelles

    NASA Astrophysics Data System (ADS)

    Doumit, Nancy

    Product development, subject to time constraints and system complexity, needs synchronous communication between different disciplines and locations in order to enable knowledge sharing. Being well supported, informal information flow increases productivity during product realization. Therefore, manufacturing industries are exploring the use of Enterprise Social Media (ESM) functionalities. This thesis explores the functional integration of formal information technologies such as Product Lifecycle Management (PLM) software with informal technologies as ESM through an industrial case study. Reviewing literature, the candidate has identified a gap between Virtual Communities of Practice (VCoP) and product development, as well as the correlation of PLM solutions and noncontrolled ESM in the aerospace industry. In order to disseminate a descriptive study of the current collaboration status, the author has undertaken online surveys for geodistant employees of the same department, semi-structured interviews and research among existing documentations. Subsequently, a Quality Functional Analysis is performed via two modified House of Quality matrices (PLM and ESM) to assign a convenient support for information transfer independently of its content maturity. Users' needs are categorized, and for each category a choice of platform is made with further recommendation regarding the use of the function or the need of human intervention. VCoP form an integrated part of the solution where employees support the technical content. Thus, essential roles and responsibilities are presented to maintain existing CoP and develop new ones. Finally, the candidate presents the limits of this research, gives recommendations for the manufacturing industry and suggests potential continuation of this study using PLM 2.0 with noncontrolled ESM tools.

  12. Etude de sensibilite du profil de durete des engrenages traites thermiquement par induction en fonction des parametres machine

    NASA Astrophysics Data System (ADS)

    Barka, Noureddine

    This project involves a study of sensitivity of the hardness profile of cylindrical bars and spur gears heated by induction using finite element models (axisymmetric and 2D) combined with experimental tests. This sensitivity study is considered as the basic step towards the development of prediction models. The study mainly aims at evaluating the effect of material properties and machine parameters on the hardness profile. As the induction heating is very fast, it is reasonable to assume that the material properties are different from those measured under thermodynamic equilibrium conditions. For this reason, the study attempts to measure the effect of variations in material properties on the surface temperature using the axisymmetric model. The results show that the relative magnetic permeability is the property that most significantly influences surface temperatures and the variation of this property has a large effect on the hardness profile. The effects of specific heat and electrical conductivity are rather low, while the thermal conductivity has a negligible effect on the model developed. Moreover, the variation in temperature of austenitizing margins have limited effects on the developed model. Therefore, the use of material properties at thermodynamic equilibrium was sufficient to establish models for predicting trends. Moreover, study of global sensitivity profile of hardness as a function of machine parameters allowed, in the first place, to compare the two cases of heat to medium and high frequency, by applying them to a disc and a gear and determine the effect of the imposed current density and heating time on the hardness profile using the results of the simulations. It appears that the edge effect is smaller in the MF heating case. In addition, the 2D model can confirm that the MF power heat more the tooth root, while the HF power heat the tooth tip region. Finally, the regression models developed were used to estimate surface temperatures and depths hardened with time of heating and power received by the part. The experimental tests, performed on discs and gears with the same exterior dimensions, have confirmed a clear correlation between hardness profiles measured and those obtained by simulation. Moreover, since the power transmitted by the machine to the coil is not known and it is difficult to measure the current in the inductor, the issue was to find a method leading to a match between simulation and experimentation. Indeed, tests have allowed the calibration of developed models by evaluating the power ratio between the power received by the part and that provided by the machine. Thus, the calibrated models are able to predict global trends of the hardness profile as a function of machine parameters even if the material properties measured at thermodynamic equilibrium are used. Finally, a local sensitivity analysis was performed by varying the machine parameters slightly around the nominal values leading to a definite hardness profile. Based on the statistical tools of variance analysis, this study showed that the hardness profile is very sensitive to small variations of the power machine and the heating time in the case of the disc. With regard to the gears and considering the dual frequency sequential heating mode, HF power and HF heating time are the parameters that most affect the hardness profile. Although the study focused on the specific geometry and a given material, it is clear that the models developed can be used to develop mechanical components and they help reduce the development time. The greatest contribution of this work has been to bridge the gap between theory, simulation and practice. Therefore, it laid the groundwork to achieve a more general and robust model capable of supporting the interactions between the machine parameters, variables, dimensions and material properties. The accuracy of the model could be greatly improved by considering inductor current measurement during heating and material properties characterization in thermodynamic nonequilibrium conditions. (Abstract shortened by UMI.)

  13. The Pedagogical Value of Leo Brouwer's "Etudes Simples": A Perspective on Preserving an Exquisite, Yet Neglected Custom

    ERIC Educational Resources Information Center

    Kronenberg, Clive W.

    2013-01-01

    The decline in the status of the classical guitar is, for many, a cause of concern, calling for viable answers to restore its place in the expressive arts tradition. In this article, I explore a pedagogical style specifically intended for young and/or inexperienced players. It is argued that this endeavor could prospectively benefit a range of…

  14. Effets Seebeck et Nernst dans les cuprates: Etude de la reconstruction de la surface de Fermi sous champ magnetique intense

    NASA Astrophysics Data System (ADS)

    Laliberte, Francis

    2010-06-01

    Ce memoire presente des mesures de transport thermoelectrique, les effets Seebeck et Nernst, dans une serie d'echantillons de supraconducteurs a haute temperature critique. Des resultats obtenus recemment au Laboratoire National des Champs Magnetiques Intenses a Grenoble sur La1.7Eu0.2Sr0.1 CuO4, La1.675Eu0.2Sr0.125CuO 4, La1.64Eu0.2Sr0.16CuO4, La1.74Eu0.1Sr0.16CuO4 et La 1.4Nd0.4Sr0.2CuO4 sont analyses. Une attention particuliere est accordee aux equations de la theorie semi-classique du transport et leur validite est verifiee. La procedure experimentale et les materiaux utilises pour concevoir les montages de mesures sont expliques en detail. Enfin, un chapitre est dedie a l'explication et l'interpretation des resultats de transport thermoelectrique sur YBa2Cu3O6+delta publies au cours de l'hiver 2010 dans les revues Nature et Physical Review Letters. Les donnees d'effet Seebeck dans les echantillons de La 1.8-x,Eu0.2SrxCuO 4, ou un changement de signe est observe, permettent de conclure a la presence d'une poche d'electrons dans la surface de Fermi qui domine le transport a basse temperature dans la region sous-dopee du diagramme de phase. Cette conclusion est similaire a celle obtenue par des mesures d'effet Hall dans YBa 2Cu3O6+delta et elle cadre bien dans un scenario de reconstruction de la surface de Fermi. Les donnees d'effet Nernst recueillies indiquent que la contribution des fluctuations supraconductrices est limitee a un modeste intervalle de temperature au-dessus de la temperature critique.

  15. Information content of the Centre d'Etude du Polymorphisme Humain (CEPH) family structures for linkage studies.

    PubMed

    Chakravarti, A

    1991-10-01

    This paper derives theoretical values for joint polymorphism information content for two markers from a family structure consisting of four grandparents, two parents, and many offspring. These data determine the efficiency of linkage map construction.

  16. Etude de Retour/Non-Retour des Étudiants Marocains en France (le cas de Lille)

    NASA Astrophysics Data System (ADS)

    El Attafi, Douieb

    1990-12-01

    Indépendamment de l'intention de retour ou de non-retour, les étudiants marocains à Lille sont en général appelés à créer leurs conditions matérielles d'existence et par là, à conduire des stratégies professionnelles et sociales d'intégration à la société française bien au delà de ce qu'exigerait un simple séjour d'étude. Ces mêmes étudiants pensent qu'au Maroc, la valorisation des qualifications acquises en France est incertaine. Le chômage des diplômés au Maroc devient une réalité de plus en plus tangible. Les étudiants marocains à Lille, incertains de pouvoir s'insérer professionnellement au Maroc, lorsqu'ils réussissent à obtenir un emploi relativement déclassé, mais qualifiant, décident de rester en France. Ceci est d'autant plus probable quand, chez les étudiants, la religion n'est pas fortement intégrée. Dans le cas contraire et lorsque ils décident de rester en France, la religion comme effet durable de la socialisation primaire, constitue un point d'ancrage plus ou moins spécifique, leur permettant de réinterpréter les ruptures vécues, sous le mode de la continuité. Tout ceci montre que dans leurs choix de retour/non-retour, les étudiants sont bien évidemment conditionnés de leur histoire individuelle et collective, mais ils n'en sont pas entièrement prisonniers.

  17. Etude des melanges co-continus d'acide polylactique et d'amidon thermoplastique (PLA/TPS)

    NASA Astrophysics Data System (ADS)

    Chavez Garcia, Maria Graciela

    Les melanges co-continus sont des melanges polymeriques ou chaque composant se trouve dans une phase continue. Pour cette raison, les caracteristiques de chacun des composants se combinent et il en resulte un materiau avec une morphologie et des proprietes particulieres. L'acide polylactique (PLA) et l'amidon thermoplastique (TPS) sont des biopolymeres qui proviennent de ressources renouvelables et qui sont biodegradables. Dans ce projet, differents melanges de PLA et TPS a une haute concentration de TPS ont ete prepares dans une extrudeuse bi-vis afin de generer des structures co-continues. Grace a la technique de lixiviation selective, le TPS est enleve pour creer une structure poreuse de PLA qui a pu etre analysee au moyen de la microtomographie R-X et de la microscopie electronique a balayage MEB. L'analyse des images 2D et 3D confirme la presence de la structure co-continue dans les melanges dont la concentration en TPS. se situe entre 66% et 80%. L'effet de deux plastifiants, le glycerol seul et le melange de glycerol et de sorbitol, dans la formulation de TPS est etudie dans ce travail. De plus, nous avons evalue l'effet du PLA greffe a l'anhydride maleique (PLAg) en tant que compatibilisant. On a trouve que la phase de TPS obtenue avec le glycerol est plus grande. L'effet de recuit sur la taille de phases est aussi analyse. Grace aux memes techniques d'analyse, on a etudie l'effet du procede de moulage par injection sur la morphologie. On a constate que les pieces injectees presentent une microstructure heterogene et differente entre la surface et le centre de la piece. Pres de la surface, une peau plus riche en PLA est presente et les phases de TPS y sont allongees sous forme de lamelles. Plus au centre de la piece, une morphologie plus cellulaire est observee pour chaque phase continue. L'effet des formulations sur les proprietes mecaniques a aussi ete etudie. Les pieces injectees dont la concentration de TPS est plus grande presentent une moindre resistance a la traction. La presence du compatibilisant dans la region co-continue affecte negativement cette resistance. En considerant que l'amidon est un biomateriau abondant, moins cher et plus rapidement biodegradable, son ajout dans le PLA presente l'avantage de reduire le cout tout en augmentant la vitesse de degradation du PLA. De plus, une structure continue poreuse de PLA produit par la technique de lixiviation selective a des applications potentielles soit comme materiau a degradation rapide ou encore, une fois la phase TPS retiree, comme substrat a porosite ouverte pour la fabrication de membranes, de supports cellulaires ou de filtres. Mots-cles : melanges immiscibles, acide polylactique, amidon thermoplastique, morphologie cocontinue, lixiviation selective, microtomographie R-X, materiau rigide poreux biodegradable.

  18. Economie et enseignement a Madagascar. (Economy and Education in Madagascar.) Financement des systemes educatifs: etudes de cas Nationales 8.

    ERIC Educational Resources Information Center

    Hugon, Philippe

    The purpose of this volume is to analyze the problems of school finance in Madagascar, including those that have arisen in the past decade and those anticipated in the present decade (through 1980). More generally, this book examines past and future connections between the economic and educational systems in Madagascar. The author examines the…

  19. The Shock and Vibration Digest. Volume 13. Number 2

    DTIC Science & Technology

    1981-02-01

    Hoffmann, C. Jeandidier, and M. Livolant Dept. des Etudes Mecaniques et Thermiques, CEA 8 146 Centre d’Etudes NuCleaires do SaclaY, Gifsur-Yvettc...simulations that are used to predict the effects of postuleted Method accident sequences. Comparisons were made of predictions with data from four...d’Etudes Nucleaires de Saclay, Gifsur-Yvette, France, Rept. No. CONF-7595894, 10 pp (1978) CEA-CONF-4372 OFF-SHORE STRUCTURES Key Words: Nuclear

  20. Searching near-replicas of images via clustering

    NASA Astrophysics Data System (ADS)

    Chang, Edward Y.; Li, Chen; Wang, James Z.; Mork, Peter; Wiederhold, Gio

    1999-08-01

    Internet piracy has been one of the major concerns for Web publishing. In this study we present a system, RIME, that we have prototyped for detecting unauthorized image copying on the WWW. To speed up the copy detection, RIME uses a new clustering/hashing approach that first clusters similar images on adjacent disk cylinders and then builds indexes to access the clusters made in this way. Searching for the replicas of an image often takes just one IO to loop up the location of the cluster containing similar objects and one sequential file IO to read in this cluster. Our experimental results show that RIME can detect images copies both more efficiently and effectively than the traditional content- based image retrieval systems that use tree-like structures to index images. In addition, RIME copes well with image format conversion, resampling, requantization and geometric transformation.

  1. Evaluation of Mixed-Phase Microphysics Within Winter Storms using Field Data and In Situ Observations

    NASA Technical Reports Server (NTRS)

    Colle, Brian A.; Yu, Ruyi; Molthan, Andrew L.; Nesbitt, Stephen

    2014-01-01

    It is hypothesized that microphysical predictions have greater uncertainties/errors when there are complex interactions that result from mixedphased processes like riming. Use Global Precipitation Measurement (GPM) Mission ground validation studies in Ontario, Canada to verify and improve parameterizations

  2. Montblanc1: GPU accelerated radio interferometer measurement equations in support of Bayesian inference for radio observations

    NASA Astrophysics Data System (ADS)

    Perkins, S. J.; Marais, P. C.; Zwart, J. T. L.; Natarajan, I.; Tasse, C.; Smirnov, O.

    2015-09-01

    We present Montblanc, a GPU implementation of the Radio interferometer measurement equation (RIME) in support of the Bayesian inference for radio observations (BIRO) technique. BIRO uses Bayesian inference to select sky models that best match the visibilities observed by a radio interferometer. To accomplish this, BIRO evaluates the RIME multiple times, varying sky model parameters to produce multiple model visibilities. χ2 values computed from the model and observed visibilities are used as likelihood values to drive the Bayesian sampling process and select the best sky model. As most of the elements of the RIME and χ2 calculation are independent of one another, they are highly amenable to parallel computation. Additionally, Montblanc caters for iterative RIME evaluation to produce multiple χ2 values. Modified model parameters are transferred to the GPU between each iteration. We implemented Montblanc as a Python package based upon NVIDIA's CUDA architecture. As such, it is easy to extend and implement different pipelines. At present, Montblanc supports point and Gaussian morphologies, but is designed for easy addition of new source profiles. Montblanc's RIME implementation is performant: On an NVIDIA K40, it is approximately 250 times faster than MEQTREES on a dual hexacore Intel E5-2620v2 CPU. Compared to the OSKAR simulator's GPU-implemented RIME components it is 7.7 and 12 times faster on the same K40 for single and double-precision floating point respectively. However, OSKAR's RIME implementation is more general than Montblanc's BIRO-tailored RIME. Theoretical analysis of Montblanc's dominant CUDA kernel suggests that it is memory bound. In practice, profiling shows that is balanced between compute and memory, as much of the data required by the problem is retained in L1 and L2 caches.

  3. Actes du colloque sur le bilinguisme, Universite de Neuchatel, 14/15 Septembre, 1981 (Proceedings of the Colloquium on Bilingualism, University of Neuchatel, September 14-15, 1981).

    ERIC Educational Resources Information Center

    TRANEL, 1982

    1982-01-01

    This issue contains proceedings of a colloquium on linguistics at the University of Neuchatel: (1) "Propositions epistemologiques pour une etude du bilinguisme (Epistemological Propositions for a Study of Bilingualism)," by B. Py; (2) "Comment on di ca? Prolegomenes a une etude de la composante semantique du langage des migrants (How Do You Say…

  4. New Fluoride Glasses for the Preparation of Infrared Optical Fibers.

    DTIC Science & Technology

    1987-09-01

    LUCAS, University of Rennes Contractor: CENTRE REGIONAL ETUDES BRETAGNE SCIENCES, CREBS PRESIDENCE DE L’UNIVERSITE, Rue du Thabor - 35000 RENNES (France...OFFICE NAME AND ADDRESS 1Z. REPORT OATE CENTRE REGIONAL ETUDES BRETAGNE SCIENCES Sept. 1986 - Sept. 1987 I"’. NUMBER OF PAGES Pr~sidence Ic

  5. Workshop on MQW Mixing and its Application to Optoelectronic Devices

    DTIC Science & Technology

    1990-09-01

    Gao, M Quillec, H Thibierge, P Krauz and P Blanconnier Centre National d’Etudes des T6l6communications, Laboratoire de Bagneux, Bagneux, France 16.05...Rao, P Ossart, Y Gao, M Quillec, H Thibierge, P Krauz and P Blanconnier Centre National d’Etudes des T6lcommunications, Laboratoire de Bagneux, 196

  6. Laser Speckle from Thin and Cascaded Diffusers

    DTIC Science & Technology

    1988-05-01

    24. N. G. Gaggioli and M. L. Roblin, "Etudes des etats de surface par les properties de diffusion a l’infini en lumiere transmise," Opt. Commun. 32...N. G. Gaggioli and M. L. Roblin, "Etudes des etats de surface par les properties de diffusion a l’infini en lumiere transmise," Opt. Commun. 32, 209

  7. Prostate Cancer Risk in Relation to IGF-1 and its Genetic Determinants: A Case Control Study Within the Cancer Prostate Sweden Project (CAPS)

    DTIC Science & Technology

    2007-05-01

    www.interscience. wiley.com). Abbreviations: CAPS, Cancer Prostate in Sweden; CEPH, Centre d’Etude du Polymorphisme Humain; htSNPs, haplotype tagging...downloading genotype data for 30 Caucasian Centre d’Etude du Polymorphisme Humain (CEPH) trios from the HapMap Phase 1 data base,15 covering the IGF1

  8. Developpement de techniques de diagnostic non intrusif par tomographie optique

    NASA Astrophysics Data System (ADS)

    Dubot, Fabien

    Que ce soit dans les domaines des procedes industriels ou de l'imagerie medicale, on a assiste ces deux dernieres decennies a un developpement croissant des techniques optiques de diagnostic. L'engouement pour ces methodes repose principalement sur le fait qu'elles sont totalement non invasives, qu'elle utilisent des sources de rayonnement non nocives pour l'homme et l'environnement et qu'elles sont relativement peu couteuses et faciles a mettre en oeuvre comparees aux autres techniques d'imagerie. Une de ces techniques est la Tomographie Optique Diffuse (TOD). Cette methode d'imagerie tridimensionnelle consiste a caracteriser les proprietes radiatives d'un Milieu Semi-Transparent (MST) a partir de mesures optiques dans le proche infrarouge obtenues a l'aide d'un ensemble de sources et detecteurs situes sur la frontiere du domaine sonde. Elle repose notamment sur un modele direct de propagation de la lumiere dans le MST, fournissant les predictions, et un algorithme de minimisation d'une fonction de cout integrant les predictions et les mesures, permettant la reconstruction des parametres d'interet. Dans ce travail, le modele direct est l'approximation diffuse de l'equation de transfert radiatif dans le regime frequentiel tandis que les parametres d'interet sont les distributions spatiales des coefficients d'absorption et de diffusion reduit. Cette these est consacree au developpement d'une methode inverse robuste pour la resolution du probleme de TOD dans le domaine frequentiel. Pour repondre a cet objectif, ce travail est structure en trois parties qui constituent les principaux axes de la these. Premierement, une comparaison des algorithmes de Gauss-Newton amorti et de Broyden- Fletcher-Goldfarb-Shanno (BFGS) est proposee dans le cas bidimensionnel. Deux methodes de regularisation sont combinees pour chacun des deux algorithmes, a savoir la reduction de la dimension de l'espace de controle basee sur le maillage et la regularisation par penalisation de Tikhonov

  9. Radiations cosmiques : danger dans l'Espace

    NASA Astrophysics Data System (ADS)

    Bonnet-Bidaud, J. M.; Dzitko, H.

    2000-06-01

    Au sol, l'atmosphere nous protege plus ou moins bien. Mais dans l'espace ou a bord des avions de ligne, l'homme est directement expose aux rayonnements cosmiques qui peuvent etre mortels. Un veritable frein a la presence humaine prolongee dans l'espace. Une menace que les agences spatiales prennent tres au serieux.

  10. Technical Programme 1993 (Le Programme Technique, 1993)

    DTIC Science & Technology

    1992-09-01

    Symposium sur "Les Effets de la Propagation Atmospherique a travers des Obscurcissants Naturels et Artificiels sur le Rayonnement des Ondes Millimetriques...for Small Gas Turbines" Reunion du Panel et Symposium sur "Les Technologies pour les Petites Turbines a Gaz " 4-8 CANADA TIP Panel Meeting/Specialists

  11. Modelling end Measurement of Atmospheric Turbulence over Land

    DTIC Science & Technology

    1996-07-01

    standard, auxquels on ajoute le rayonnement solaire et les parametres caracteristiques du terrain. On compare les resultats obtenus aux mesures de Cn 2 et...OF MODEL AND MEASUREMENTS Figures 6 shows measurements during a four day period from midnight local time Aug. 23 to midnight Aug. 27, 1995. The

  12. Francais: Programme d'etudes par annee scolaire. Francais langue premiere: Septieme annee (French: Yearly Curriculum. French as a Native Language: Seventh Year).

    ERIC Educational Resources Information Center

    Alberta Dept. of Education, Edmonton. Language Services Branch.

    The report, entirely in French, describes Alberta's curriculum for seventh-year French native language instruction, as revised in 1998. An introductory section offers background information on the curriculum's design, links between the core curriculum and French native language instruction, underlying principles of language instruction, the…

  13. Francais: Programme d'etudes du secondaire deuxieme cycle (10-12). Francais langue premiere (French: High School Curriculum [10-12]. French as a Native Language).

    ERIC Educational Resources Information Center

    Alberta Dept. of Education, Edmonton. Language Services Branch.

    The report, entirely in French, describes Alberta's curriculum for high school French native language instruction, as revised in 1998. An introductory section offers background information on the curriculum's design, links between the core curriculum and French native language instruction, underlying principles of language instruction, the…

  14. Francais: Programme d'etudes par annee scolaire. Francais langue premiere: Neuvieme annee (French: Yearly curriculum. French as a Native Language: Ninth year).

    ERIC Educational Resources Information Center

    Alberta Dept. of Education, Edmonton. Language Services Branch.

    The report, entirely in French, describes Alberta's curriculum for ninth-year French native language instruction, as revised in 1998. An introductory section offers background information on the curriculum's design, links between the core curriculum and French native language instruction, underlying principles of language instruction, the…

  15. Francais: Programme d'etudes par annee scolaire. Francais langue premiere: Huitieme annee (French: Yearly Curriculum. French as a Native Language: Eighth Year).

    ERIC Educational Resources Information Center

    Alberta Dept. of Education, Edmonton. Language Services Branch.

    The report, entirely in French, describes Alberta's curriculum for eighth-year French native language instruction, as revised in 1998. An introductory section offers background information on the curriculum's design, links between the core curriculum and French native language instruction, underlying principles of language instruction, the…

  16. Special Course on Unstructured Grid Methods for Advection Dominated Flows (Les Methodes Utilisant un Maillage non Structure Pour l’Etude des Ecoulements Caracterises par l’Advection)

    DTIC Science & Technology

    1992-05-01

    prisms t;- xIll with r a triangle or "tilted" such prisms , -k ( A n- ) x A ii" Ai u I)T jor tetrahedrons. Define for q _ 0 i Vl ={vL2(Sn{): vI KE(IPq...cont’d 1-47 ’Tv I 1I / _ Reference prism "Tilted prism " ,/ \\, 11 Fmo f Stn-I /7’/’/7171:1+ S~FIG. S - Space-time discrctization of the SD-method H " 2-1...impilnlentlltionI of tree strllucilres. Tihis is required so that now N, 0 I ndes coln be ticoed in the memory space released by the dolotion of -.. 0 previous

  17. Methodologie d'evaluation de la demande de chaleur des groupes de batiments dans le cadre d'une etude de faisabilite du chauffage urbain

    NASA Astrophysics Data System (ADS)

    Quirion-Blais, Olivier

    In the context of energy efficiency improvements to pulp and paper mills, process modifications allow to free low quality steam. This kind of low pressure and temperature steam is often found to be in excess in mills. New opportunities to use this energy could be created by gathering plants along with local communities and other enterprises into eco-industrial clusters. Following this proposition, district heating is an interesting technology that could be developed. It consists in supplying buildings with steam or hot water from one or more central heating plants through a series of canalization, generally underground. The supplied energy is used mostly for space heating but it can also be used with appliances specially designed for this purpose. Under certain conditions, this type of heating is cheaper and more environmentally friendly for several reasons including the facts that one central boiler plant is more efficient and has lower pollutant emissions due to better combustion control. Moreover, it can be adapted to multiple fuels that are locally available such as biomass around some pulp and paper mills. However, to insure that the savings occur, the heat demand must be sufficiently high and concentrated. Therefore, detailed feasibility studies shall be conducted to justify significant investments. Such studies require a lot of time not to mention that they necessitate a lot of data which can be difficult to obtain. The objective of this work is to develop a methodology that can assess the feasibility of district heating quickly and using easily accessible data. It was mainly designed to determine the heat consumption, which is especially critical as to decide whether or not to implement this technology. The focus is primarily directed on residential buildings, but another methodology is also developed to take into account the commercial and institutional buildings demand. An analysis of the sources of data revealed a certain redundancy among them. Therefore, four different computation procedures were developed to obtain the heat consumption of residential buildings: • C1, the first procedure, is the most time consuming one. It is also the one that uses the most specific information from the case: aerial photographs, census data (building year of construction and type (single family detached, single family attached, apartments or mobile homes)) and punctual on-site verification from the target area. National estimates of thermal requirements values are also used. • C2, the second procedure, is less specific than C1, but is much less time consuming to achieve. The local data sources used are: aerial photographs and census data from the case. While the national ones are: estimates of the building heating surfaces and thermal requirements. • C3 and C4, are the easiest procedures. Those two are very similar. The specific data used in these cases are census data from the locations under study. National data used for C3 are building surface estimates and thermal requirements values while C4 only uses thermal requirement values which are slightly different from those of C3. A further analysis revealed later that these two calculations yielded the same results. Therefore, since C3 is slightly more complicated to implement, it was removed from further analysis. Using three procedures thus ensures the stability of the methodology when the three results are the same order of magnitude. An average of the three results gives a good estimation of the consumption. The methodology was then applied to four study cases. One of them has already been the subject of a detailed district heating assessment feasibility study. It is used to validate the results obtained with the new methodology. The three other cases are rather used to test different conditions (number, density, type and year of construction of buildings). The validation results showed that the methodology can determine the heat consumption to about 20% of the baseline value. It also determines the total heating surface to about 5%. The three other study cases, A, B and C, have confirmed that possibility of applying the methodology in various conditions. Case A showed lower gaps between the four procedures when the rate of single family houses is lower. Since this rate is high in the validation case, better results can be expected for cases where the number of single family houses is low, such as in case A. In case B, the global results showed a particularly low gap between the four procedures with a maximum of 5%. However, an analysis of individual dissemination areas showed higher positive and negative gaps, which, when they are summed, compensate for the individual errors. The bigger errors in this case are explained by the fact that the apartments in this city are larger than the national average. Case C presented an additional challenge since no aerial photo was available. It has nevertheless been possible to realize two calculation procedures, C3 and C4, which provided a broad approximation of the consumption. For the commercial sector, a similar methodology to that of the residential sector is developed. However, the lack of global data has prescribed the individual processing of every building. This approach is also justified by the fact that commercial and institutional buildings are less numerous and have higher consumption. Due to the extended duration of this type of approach, only the validation and case Aare realized. The first one confirmed the better results than the ones from the residential sector with a gap of 7% compared to the consumption baseline. The results from case A showed the areas where the heat consumption is higher. Furthermore, it showed that the commercial and institutional demand accounts for 10% to 40% of the total heat demand. The integration of the results obtained into a district heating feasibility study is then discussed. A joint analysis of the residential and the commercial and institutional sectors showed the importance of considering each building's heat consumption for the planning of a district heating network. The profitability of the study cases is considered in relation to the thermal thresholds suggested in the literature.

  18. Etudes sociales 30. Sujet B: Interaction entre nations. Cahier de l'eleve. Edition finale = Social Studies 30. Subject B: Interaction between Nations. Student Workbook. Final Edition.

    ERIC Educational Resources Information Center

    Alberta Dept. of Education, Edmonton. Curriculum Branch.

    In this Alberta (Canada) student workbook, four history units are presented for study. These are: (1) Between Two Wars (1919-1936); (2) World War II; (3) The Emergence and Interaction of the Superpowers; and (4) Contemporary World Interactions. Advice is offered to students in each unit along with information about key events and issues during…

  19. Etude des transitions de phases de NH 3(CH 2) 2NH 3(H 2PO 4) 2 par mesures optique, dielectrique et de thermocourant

    NASA Astrophysics Data System (ADS)

    Kamoun, S.; Daoud, A.; Von Der Muhll, R.; Ravez, J.

    1993-02-01

    Dielectric, birefringence and thermocurrent measurements have been carried out on NH 3(CH 2) 2NH 3(H 2PO 4) 2 single crystal. Three transitions have been detected at about T 1 = (264 + 4), T 2 = (241 + 5) and T 3 = (141 + 5) K. In the low temperature phases a polarization current of about 10 -8 - 10 -9 A is obtained and can be reversed when the sign of the polarization field is changed, a property which could correspond to a ferroelectric behaviour. However, no pyroelectric current is detected when the temperature decreases from T t. Another hypothesis, based on a field - induced polarization, has been considered : the depolarization current could be due to charge displacements from potential minima favored by rising temperature. In any way, the low - temperature phases are characterized by a remanent polarization.

  20. Etude des Coefficients du Viriel de la Constante Dielectrique des Gaz Atomiques et de L'azote EN Fonction de la Temperature

    NASA Astrophysics Data System (ADS)

    Huot, Jacques

    1990-01-01

    Le but principal de notre travail fut d'etudier le deuxieme coefficient du viriel de la constante dielectrique (B_epsilon) des gaz atomiques en fonction de la temperature. Nous avons developpe une technique differentielle afin de determiner B_ epsilon avec precision. Les mesures furent effectuees a 77.4 K, 242.95 K, 323.15 K et 407.6 K et a des pressions allant jusqu'a 600 bars. Pour tous les gaz atomiques, nous avons mesure un accroissement de la valeur de B_epsilon lorsque la temperature diminue. Nos resultats precis de B_epsilon en fonction de la temperature vont permettre d'ameliorer les calculs ab-initio existants. Le B_ epsilon des gaz atomiques semble presenter un comportement universel similaire a celui du deuxieme coefficient du viriel de la pression (B_ {rm P}). Pour l'azote, la valeur du moment quadrupolaire que nous avons mesuree est en accord avec la valeur theorique ainsi qu'avec les valeurs determinees par d'autres methodes experimentales.

  1. Etude des parametres physiques en vue d'applications medicales de l'actionnement magnetique de dispositifs medicaux par un systeme d'imagerie par resonance magnetique

    NASA Astrophysics Data System (ADS)

    Mathieu, Jean-Baptiste

    An actuation and control method for medical devices based on the magnetic gradient coils of a Magnetic Resonance Imaging (MRI) was proposed for the first time in 2002 by NanoRobotics Laboratory [1]. The work undertaken in the present thesis began in the context of demonstrating the concept of automatic navigation of a magnetic bead in vivo. From the point of view of actuation, models and experimental data correlate. A maximum velocity of 13cm/s was measured for a 1.5mm diameter chrome steel bead in the carotid artery of a living swine. The bead was under the influence of magnetic gradients applied by a clinical MRI system without any hardware modification. In light of these results, the aim of this thesis is the study of the physical parameters involved in the development of a first medical application: the steering of magnetic particles in MRI in the context of drug targeting. It was demonstrated that an MRI system equipped with a set of magnetic gradient coils with enhanced amplitude was able to apply a high enough actuation force to act upon magnetic microparticles suspended in a liquid. General rules for MRI actuation were identified. First of all, increasing the amplitude of the main magnetic field of the MRI leads to the increase of the actuation force amplitude only until the ferromagnetic body reaches its saturation magnetization. Moreover, soft ferromagnetic bodies appear to be better candidates for MRI based magnetic actuation because they can reach high saturation magnetizations. Magnetic gradient amplitude appears as a foremost factor to increase the amplitude of the magnetic force. Clinical MRI systems do not provide gradients with high enough amplitude for the applications studied here. Theoretical models developed in this thesis predict that a one order of magnitude increase in gradient amplitude would be required. Implementing actuation dedicated gradient coils is therefore suggested. Finally, a larger ferromagnetic body will lead to higher magnetophoretic velocities for magnetic particles. In the context of magnetic microparticle targeting for cancer treatment through embolisation, the scaling laws bridging from the preliminary works with millimeter sized beads to magnetic microparticles suspensions were studied. Magnetic microparticles suspensions injected through branching channels were guided in MRI under the influence of magnetic gradients. The goal of these experiments was to maximize the amount of particles flowing through one of the outlets of the channel. The outcome of the experiments was quantified using an optical set-up as well as by analyzing the suspension at each outlet of the channels. The most important parameters that were identified are the magnetic force amplitude, the interactions and aggregation between magnetic particles of the suspension, the size, geometry and density of the particles or aggregates driven, the dimensions of the channel and the intensity of the flow. Mathematical models based on analyses of particle trajectories and on non dimensionalization of the experimental parameters were proposed. The model predicts steering efficiencies in the order of what was recorded experimentally. Nevertheless, some parameters that remain to be quantified more precisely like the effects of magnetic aggregation and friction forces cause discrepancies between theoretical and experimental data. Despite these differences, the knowledge gained in the field of magnetic suspension steering appears to be sufficient to envision in vivo experiments lead in parallel with improving the theoretical predictions. Hence, an experimental set-up and an experimental protocol are being designed to adapt the steering methods to interventional procedures and animal subjects. Finally, the same principles used for microparticle steering can be applied for magnetic catheter navigation. Hence, on the side of the main subject of this thesis, the deflection of magnetic catheters by MRI was also studied as a second medical application. Using magnetic catheter and guide wires could facilitate the placement of medical instruments and accelerate medical procedures. The recorded deflections are lower than the ones measured with other magnetic guidance systems. The parameters and performances obtained are functions of the amplitude of the applied magnetic force and material strength properties of the catheters or guide wires. Hence, deflection could be enhanced by adapting the mechanical properties of the devices, by increasing the amplitude of the magnetic gradient or the volume and magnetization of the magnetic tip. These latter results are the object of an upcoming patent application. Hence, the paper relating them could not be submitted prior to the submission date of this thesis. For this reason, this paper's manuscript is presented as an annex of the present document

  2. Contribution a l'etude et a la conception d'une machine synchrone a flux transverse destinee au degivrage d'aeronefs en cours de vol

    NASA Astrophysics Data System (ADS)

    Boussetoua, Mohammed

    During winter, the climate in the northern region is known for its icing and freezing conditions. However, emergency services often use helicopters to reach isolated locations. The difficult situations, generally experiences in the North particularly in Quebec, may prevent rescuers to intervene. The main reason preventing such operations is the lack of a de-icing system in the small helicopter blades. The overall objective of the project is research, development, design and manufacture of a system composed of an on-board rotating low speed generator and heating elements. It consumes a part of the power supplied by the turbine through the axis of the main rotor of the small aircraft and converts it to electrical power to be used by the heating elements. This innovation will allow to fly safely everywhere throughout the year protect the lives of the users even in the worst weather conditions. Firstly, the research focuses on the identification of problems related to the use of protection systems against the hoarfrost on main rotor blades of different aircrafts during flight. In this phase, we specifically focused on the difficulties encountered by the aircraft companies using the existing and operational systems for protection against hoarfrost. Main rotor blades are difficult to protect on helicopters. Several systems were considered by the helicopter manufacturers, such as electrothermal systems, pneumatic systems or using anti-icing fluids. In the current state of technological knowledge, all helicopters that have been certified to fly in icing conditions use electrothermal systems for protection against hoarfrost on their main rotor Small helicopters addressed by this work, are forbidden to fly in icing conditions due to lack of energy source to operate these systems. The electrothermal system has been considered for this thesis work to protect the main rotor blades of small aircraft in-flight. The second part of this thesis is based on the source of power feeding the hearting system. In recent years, numerous research studies have started on the development of electromechanical system converters for various applications, such as transport by road, rail or aviation. The development of new low-speed, low-weight electric machines and their very high degree of compactness has become a very promising alternative. This project strongly interests many industries in the field of air transport. The transverse flux machine is considered as a compact structure having better mass power compared to other electrical machines. The design of transverse flux machine was the subject of an electromagnetic study. Also, the analytical study helped to determine the overall dimensions of the machine. The study was followed by a validation phase of the analytical model using numerical simulations. These two studies were intended to determine changes in the characteristics of the transverse flux machine according to the different geometric dimensions of its active parts. From the calculations made using analytical and numerical models, a prototype of the transverse flux machine (600 W, 320 RPM) was designed and manufactured in the AMIL laboratory at the Universite du Quebec a Chicoutimi (UQAC). A bench test was conducted to compare the theoretical and experimental results. The measurements obtained on this prototype were compared with the theoretical results. This phase of the study demonstrates with satisfaction, the reliability of the theoretical models developed. Finally, a new configuration of this machine has been proposed. Numerical simulation results of this structure are particularly encouraging and require further investigations. For logistical and financial reasons, the prototype of this configuration has not been manufactured. (Abstract shortened by UMI.)

  3. Etude de la transmission sonore par voie externe d'un bouchon d'oreille couple au conduit auditif: Modelisation numerique et validation experimentale

    NASA Astrophysics Data System (ADS)

    Viallet, Guilhem

    The objective of this thesis is to contribute to the better understanding of the problem of the sound transmission through the earplug-earcanal system to improve the design of the protector, to contribute to a better assessment of its effectiveness and thus ultimately to improve the worker's protection. This objective is accomplished via a methodological development of a predicting tool to simulate the attenuation in the framework of a step by step modeling approach which integrates gradually geometrical and physical complexities. In the first step, only the geometrical aspect of the ear canal is studied via the question of the validity of a simplified 2D axisymmetric description of the ear canal geometry in the case of rigid boundary conditions. This choice of boundary conditions allows in a first approximation to set aside the problems associated with the integration of the earcanal constitutive tissues. This question is investigated through comparisons of attenuation predictions with 2D and 3D models, and for individual or averaged over a group cases. The emphasis is put on finding the most reliable 2D geometry reconstruction method (in terms of attenuation prediction) which can be used, in order to define a 2D axisymmetric geometry based on geometrical characteristics of a 3D one. In the second step, the previous 2D model is extended to take into account a layer of skin on the ear canal walls. This also corresponds to a configuration of the synthetic earcanal included in the acoustical test fixtures that are commonly used to measure the attenuation. The role of the skin and its effect on the earplug attenuation are studied. The contributions of the different acoustic pathways due to an airborne excitation are quantified. More generally, the investigation concerns the energy circulating within the domain. In addition, statistical analyses were performed to quantify the effect on the attenuation of the mechanical parameters of both the skin and the earplug. In the third step, the previous model is extended to take into account the others tissues surrounding the ear canal (bone and soft tissues). Moreover, the previous geometry (the cylindrical one) is partially modified to obtain an average 2D axisymmetric ear canal geometry with a variable cross section. This model is first validated by comparisons with measurements on human subjects and then exploited to quantify the impact of various factors known to vary the attenuation when measured in laboratory conditions. These factors are: the possible presence of leaks, the insertion depth of the earplug, the inter-individual variation of the ear canal geometry and the variation of the mechanical parameters associated with the surrounding tissues. These factors are introduced one by one in the model and their impact on the attenuation is quantified and thereafter compared to standard deviations obtained from attenuation measurements on human subjects. Such comparisons are used to evaluate the predominance (as a function of the frequency) of the aforementioned factor effects on the attenuation. In the fourth step, the study goes into the possibility of replacing the surrounding tissues of the ear canal by mechanical impedance boundary conditions. This work ultimately aims to simplify the models developed in the third step, by using models of steps 1 and 2 improved by the mechanical impedance boundary conditions rather than the more conventional condition limits (the fixed one) used till now. Two tissue replacement scenarios have been tested in the 2D axisymmetric configuration described in the first approximation. In the first scenario (similar to step 1), the effect of all the tissues (skin, soft tissue and bone) were reduced to a mechanical impedance. A second scenario, a little less simplified, where only the bone and soft tissue domains are replaced is then considered. This second scenario allowed to correct the limitations obtained in the first scenario and helped to achieve more realism in terms of attenuation predictions, closer than those obtained with the model developed in step 3. These tests were performed on a unique geometry that does not allow generalizing the method validation which could be extended in future works to 3D models or 2D axisymmetric models with variable cross sections. From a scientific point of view, each of the steps described above helped to better understand the key mechanisms involved in the attenuation of an earplug, the pathways leading the acoustic transmission in the case of an airborne sound excitation through the occluded ear canal, and to investigate the possible simplification which can be done to predict a realistic attenuation with a numerical model. From a technological point of view, the sensitivity analyses performed on the earplug mechanical parameters with the modeling tools developed in this thesis provide concrete ways for the manufacturers to improve their product effectiveness. (Abstract shortened by UMI.).

  4. [Recent data on the epidemiology of non-Hodgkin lymphoma. Groupe d'Etudes des Lymphomes de l'Adulte (GELA)].

    PubMed

    Bosly, A; Coiffier, B

    1997-06-01

    Non-Hodgkin's lymphoma is a common condition whose incidence has increased by 75% over the last 15 years. The HIV epidemic is among the factors that have contributed to this increase: patients with AIDS have 1% annual risk of developing non-Hodgkin's lymphoma, and the increase in survival of AIDS patients has led to an increase in the frequency of AIDS-associated lymphomas. A number of other viruses are directly involved in the occurrence of lymphomas, such as the HTLV-1 and the EBV. The HSV type 8 has recently been incriminated in the occurrence of lymphomas located in the cavities of the body. The role of the hepatitis C virus in the occurrence of lymphoma is controversial. Inherited or acquired immunodeficiencies (e.g., due to treatment for an autoimmune disease or transplant) are associated with an increased incidence of lymphoma. The role of toxic chemicals, especially those used in farming, is receiving increasing attention. A number of infectious diseases promote the occurrence of lymphomas; the best illustration of this link is the association between Helicobacter pylori and primary low-grade gastric lymphomas.

  5. Prognostic significance of bcl-2 protein expression in aggressive non-Hodgkin's lymphoma. Groupe d'Etude des Lymphomes de l'Adulte (GELA).

    PubMed

    Hermine, O; Haioun, C; Lepage, E; d'Agay, M F; Briere, J; Lavignac, C; Fillet, G; Salles, G; Marolleau, J P; Diebold, J; Reyas, F; Gaulard, P

    1996-01-01

    Little is known about the expression of bcl-2 protein in intermediate and high grade non-Hodgkin's lymphoma (NHL) and its clinical and prognostic significance. We performed immunohistochemical analysis of bcl-2 expression in tumoral tissue sections of 348 patients with high or intermediate grade NHL. These patients were uniformly treated with adriamycin, cyclophosphamide, vindesine, bleomycin, and prednisone (ACVBP) in the induction phase of the LNH87 protocol. Fifty eight cases were excluded due to inadequate staining. Of the 290 remaining patients, 131 (45%) disclosed homogeneous positivity (high bcl-2 expression) in virtually all tumor cells, whereas 65 (23%) were negative and 94 (32%) exhibited intermediate staining. High bcl-2 expression was more frequent in B-cell NHL (109 of 214, 51%) than in T-cell NHL (6 of 35, 17%) (P = .0004), and was heterogeneously distributed among the different histological subtypes. Further analysis was performed on the 151 patients with diffuse large B-cell lymphoma (centroblastic and immunoblastic) to assess the clinical significance and potential prognostic value of bcl-2 expression in the most frequent and homogeneous immunohistological subgroup. High bcl-2 expression, found in 44% of these patients (67 of 151), was more frequently associated with III-IV stage disease (P = .002). Reduced disease-free survival (DFS) (P < .01) and overall survival (P < .05) were demonstrated in the patients with high bcl-2 expression. Indeed, the 3-year estimates of DFS and overall survival were 60% and 61%, respectively (high bcl-2 expression) versus 82% and 78%, respectively (negative/intermediate bcl-2 expression). A multivariate regression analysis confirmed the independent effect of bcl-2 protein expression on DFS. Thus bcl-2 protein expression, as demonstrated in routinely paraffin-embedded tissue, appears to be predictive of poor DFS, in agreement with the role of bcl-2 in chemotherapy-induced apoptosis. It might be considered as a new independent biologic prognostic parameter, which, especially in diffuse large B-cell NHL, could aid in the identification of patient risk groups.

  6. Prognostic significance of T-cell phenotype in aggressive non-Hodgkin's lymphomas. Groupe d'Etudes des Lymphomes de l'Adulte (GELA).

    PubMed

    Gisselbrecht, C; Gaulard, P; Lepage, E; Coiffier, B; Brière, J; Haioun, C; Cazals-Hatem, D; Bosly, A; Xerri, L; Tilly, H; Berger, F; Bouhabdallah, R; Diebold, J

    1998-07-01

    Peripheral T-cell lymphomas (PTCL) have been generally reported to have a worse prognosis than B-cell lymphomas (BCL). Because of their heterogeneity and scarcity, the outcomes of the different histological subtypes have not been compared. From October 1987 to March 1993, 1,883 patients with diffuse aggressive non-Hodgkin's lymphomas (NHL) included in the LNH87 protocol could be assessed for both morphology and immunophenotyping. Among them, 288 (15%) had PTCL and 1,595 (85%) had BCL. According to the Kiel classification, most PTCL were classified as angioimmunoblastic (AIL; 23%), pleomorphic medium and large T-cell (PML; 49%), or anaplastic large cell (ALCL; 20%) lymphomas. Comparing PTCL with BCL patients, the former had more disseminated disease (78% v 58%), B symptoms (57% v 40%), bone marrow involvement (31% v 17%), skin involvement (21% v 4%), and increased beta2-microglobulin (50% v 34%), whereas BCL patients had more bulky disease (41% v 26%). According to the International Prognostic Index (IPI), PTCL and BCL scores were, respectively: 0 factors, 13% and 15%; 1 factor, 17% and 22%; 2 factors, 24% and 25%; >/=3 factors, 45% and 37% (P = .09). For BCL and PTCL, respectively, complete remission rates were 63% and 54% (P = .004); the 5-year overall survival (OS) rates were 53% and 41% (P = .0004) and event-free survival (EFS) rates were 42% and 33% (P < . 0001). Comparison of the different histological subtypes of lymphoma showed that the 5-year OS rate for T-ALCL (64%) was superior to those of other PTCL (35%) as well as diffuse large B-cell (53%) NHL. When multivariate analysis was applied using the IPI score as one factor, nonanaplastic PTCL remained an independent parameter (P = . 0004). Although the poor prognosis of non-ALCL PTCL could be due in part to the presence of adverse prognostic factors at diagnosis, this study shows that the T-cell phenotype is an independent significant factor, which should be incorporated into the definition of prognostic groups.

  7. Prognostic significance of Epstein-Barr virus in nodal peripheral T-cell lymphoma, unspecified: A Groupe d'Etude des Lymphomes de l'Adulte (GELA) study.

    PubMed

    Dupuis, Jehan; Emile, Jean-François; Mounier, Nicolas; Gisselbrecht, Christian; Martin-Garcia, Nadine; Petrella, Tony; Bouabdallah, Reda; Berger, Françoise; Delmer, Alain; Coiffier, Bertrand; Reyes, Félix; Gaulard, Philippe

    2006-12-15

    Peripheral T-cell lymphomas (PTCLs) are rare and have a dismal prognosis. The most frequent subtype is PTCL, unspecified. Epstein-Barr virus (EBV) has been detected in around 40% of cases, but its prognostic significance is not fully established. Lymph node samples from 110 patients with PTCL, unspecified included in LNH87 and LNH93 trials were available. EBV status was studied by EBV-encoded small RNA in situ hybridization (EBER-ISH). EBER-ISH showed positive cells in 45 (41%) of 110 patients. Pretreatment characteristics were comparable between positive and negative cases, except for male sex (80% versus 60%, respectively, P = .02). Only 50% of patients achieved complete remission with a 5-year event-free survival (EFS) and overall survival (OS) of 21% and 30%, respectively. EBER-ISH positivity was the sole factor linked with worse EFS, with a 5-year probability of 11% for positive patients. In univariate analysis, factors affecting OS were EBER-ISH positivity, high LDH level, and age older than 60 years. In multivariate analysis, EBER-ISH was associated with a worse OS in the elderly population. Time-dependent analysis showed that the negative impact of EBV was essentially seen in the first 2 years following diagnosis. These results warrant further studies regarding pathogenesis and specific treatment approaches for EBV-associated PTCL patients.

  8. Etude de la Morphologie et de la Cinématique de l'Emission des Raies interdites autour des Etoiles T Tauri

    NASA Astrophysics Data System (ADS)

    Lavalley, Claudia

    2000-06-01

    Le phénomène de perte de masse joue un rôle essentiel dès les premières étapes de la formation stellaire et semble être intimement lié à l'accrétion de matière sur l'étoile, probablement par l'intermédiaire de champs magnétiques permettant de convertir l'énergie cinétique accrétée, en puissance d'éjection. Les étoiles T Tauri classiques, âgées de quelques millions d'années et présentant une faible extinction, offrent un excellent cadre pour étudier les régions internes des vents stellaires. Dans ce travail, je présente les premières études sur la morphologie des jets associés aux étoiles DG Tau, CW Tau et RW Aur à une résolution angulaire de 0.1'' et sur la cinématique à deux dimensions de l'émission des raies de [O I]?6300Å, [N II]?6583Å et [S II] ?6716,6731Å dans le jet de DG Tau. Ces données ont été obtenues avec deux techniques d'observation complètement nouvelles, devenues disponibles entre 1994 et 1998 au télescope CFH, et idéalement adaptées à ce problème: l'imagerie en bande étroite derrière l'optique adaptative (PUEO) qui fournit des données à très haute résolution angulaire (~0.1''), et la spectro-imagerie intégrale de champ (TIGRE/OASIS) qui donne accès à l'information spatiale et spectrale à 2D, à haute résolution angulaire (ici ~0.5''-0.75'') et moyenne résolution spectrale (100-170 km/s). Les trois jets étudiés, résolus pour la première fois à partir de 55 u.a. de l'étoile, présentent une largeur similaire (30-35 u.a.) jusqu'à 100 u.a. et une morphologie dominée par des noeuds d'émission. Les jets des étoiles à faible excès infrarouge CW Tau et RW Aur sont très similaires aux deux autres jets des sources peu enfouies observés jusqu'à présent à la même échelle spatiale. Le jet de DG Tau, plus perturbé que les deux autres, et provenant d'une source avec une enveloppe encore importante, est aussi très similaire au seul autre jet associé à une source encore enfouie résolu à ces distances de l'étoile. Ceci donne des pistes sur l'évolution de l'interaction des jets avec l'environnement circumstellaire. La morphologie et la cinématique du jet de DG Tau suggèrent fortement une variabilité dans la vitesse d'éjection, qui pourrait aussi expliquer certains des noeuds des deux autres jets. La compatibilité d'un des noeuds observés avec les chocs en arc attendus dans une telle situation, a été bien mise en évidence. Des rapports de raies à différentes distances le long d'un jet (DG Tau) et à plusieurs intervalles de vitesses ont été obtenus ici pour la première fois. Des routines d'inversion considérant l'équilibre d'ionisation pour l'oxygène et l'azote et la fraction d'ionisation de l'hydrogène comme paramètre libre, ont permis de faire une estimation des variations de conditions d'excitation (Te, xe et ne) tout au long du jet. Une comparaison détaillée des rapports de raies observés avec les prédictions de différents modèles d'excitation, à l'aide de diagrammes rapport-rapport discriminants identifiés ici pour la première fois, favorise fortement la présence de chocs avec des vitesses de 50-100 km/s, à partir de 0.2'' de l'étoile.

  9. Clinical, biological, and endoscopic picture of attacks of Crohn's disease. Evolution on prednisolone. Groupe d'Etude Thérapeutique des Affections Inflammatoires Digestives.

    PubMed

    Modigliani, R; Mary, J Y; Simon, J F; Cortot, A; Soule, J C; Gendre, J P; Rene, E

    1990-04-01

    One hundred forty-two patients with active colonic or ileocolonic Crohn's disease were included in a multicenter prospective study. Data collection included 28 clinical, biological, and endoscopic items; the latter were recorded according to a standardized colonoscopic protocol; a previously validated endoscopic index of severity was calculated. Oral prednisolone (1 mg/kg body wt per day) was started and maintained until clinical remission and for at least 3 and at most 7 wk. A second clinical biological and endoscopic evaluation was then performed. At initial colonoscopy, mucosal lesions were, by decreasing order of frequency, superficial ulcerations, deep ulcerations, mucosal edema, erythema, pseudopolyps, aphthoid ulcers, ulcerated stenosis, and nonulcerated stenosis (93%, 74%, 48%, 44%, 41%, 35%, 10%, 8%, and 2% of cases, respectively). No correlation was found between the clinical activity index and any of the endoscopical data (lesion frequency and surface, endoscopic severity index). Ninety-two percent of patients underwent clinical remission within 7 wk of treatment. None of the 28 clinical biological and endoscopical items collected just before treatment could predict clinical response to steroids. Only 38 of the 131 patients in clinical remission were also in endoscopic remission. In conclusion, (a) the description and severity of colonoscopic lesions in active Crohn's disease have been quantified; (b) no correlation exists between clinical severity and nature, surface, or severity of endoscopic lesions; (c) Oral prednisolone (1 mg/kg body wt per day) induces a clinical remission in 92% of patients within 7 wk; (d) resistance to steroids cannot be predicted from the data collected before treatment onset; and (e) only 29% of patients in clinical remission also achieve endoscopic remission.

  10. Etude de l'action d'un traitement par voie topique sur la synthèse de la kératine pilaire chez le Rat.

    PubMed

    Zahaf, F; Oustrin, J

    1988-06-01

    Synopsis Effect of topical treatment on pilar keratine synthesis in the rat The synthesis of keratin in pre-pubic Wistar rats has been studied under the influence of topic application of a lotion containing vegetable extracts. Changes of keratin synthesis in the rat was judged by the incorporation of a tagged precursor in the rat hair: cystein S-35 administered orally. Two protocols were followed each giving similar results. The first method concerned the regularity of hair growth with one sample taken per animal, and the second required multiple sampling in the same animal. Treatments with daily applications were in the range of 7-21 days. Results were analysed statistically in comparison with untreated zones. The excipient was tested separately in parallel. This rigorous procedure was essential, since the variations between individuals was wide in spite of the rats having been selected from the same litter. Daily application of the lotion showed an increase starting on the seventh day of the synthesis of keratin; the activity of the hair samples was already increased at this time by 90 to 400% (0.05>P>0.01). After 15 days increase reached > 1000% (P<0.05). Increase found for rats treated with the excipient do not reach significance. The hair growth cycle being 21 to 30 days, further continuation of the treatment gave only relatively weak stimulation of the keratin synthesis, the passage into the telogen phase slowing the synthesis of keratin whether it was produced from bulbar pre-keratin or synthesised in the hair itself.

  11. Contribution a l'etude des mecanismes de l'adhesion de la glace a differents materiaux et application a l'evaluation des materiaux glaciophobes

    NASA Astrophysics Data System (ADS)

    Ghalmi, Zahira

    Several Nordic countries with cold climates like Canada are often subjected to ice storms causing major economic and social losses. Ice or sticky snow adhesion on power network equipment can be a significant issue in transmission and distribution of electrical energy for companies operating in these regions. The costs of such events can be substantial, particularly due to the cessation of economic activities, equipment failures, deicing techniques (active methods), and population safety. Because of such events, power companies have understood the need to develop so-called superhydrophobic and/or icephobic surfaces, which can significantly reduce ice adhesion (passive methods). Several studies have led to the development of a variety of new nanostructured surfaces using various strategies. These studies have led to the design of superhydrophobic surfaces with contact angles greater than 150 and low ice adhesion strength. In order to optimally reduce the ice adhesion strength on different substrates, better understanding of the various mechanisms involved in the icing process is essential. It is in this context and within the framework of Canada's research chair on atmospheric icing of power networks (INGIVRE) that this thesis was carried out, aiming to improve the knowledge of atmospheric icing, and explain the forces involved at the ice/substrate interface. Furthermore, the effect of contact angle, surface roughness and porosity on icing and ice/substrate interface was investigated. This study clearly showed that the electrostatic, van der Waals and hydrogen bond forces are the main contributors to ice adhesion to a surface at the molecular level. The electrostatic energy, based on the principle of image charge, depends on the type of material in contact with the ice, the distance between the ice and the material, and the types of ice surface defects. The van der Waals energy depends on the material type, the thickness of the liquid water layer, and the temperature. For its part, the energy associated with hydrogen bonds depends on the material type, temperature, droplet mass, as well as on the static and sliding contact angles. Among these three forces, the electrostatic energy is the largest. Whereas the hydrogen bond energy is larger than the van der Waals energy. However, the latter is always present as long as ice is in contact with a solid surface. The experimental study showed that ice adhesion strength depends on the surface roughness of the substrate. In the case of metals with a thin natural protective oxide layer, higher roughness leads to higher ice adhesion strength. In other words, polished metallic surfaces exhibit lower ice adhesion strengths. However, in the case of anodized aluminum surfaces coated with PTFE, the roughened needle-like structure resulted in lower ice adhesion. The experimental results showed that PTFE coatings remain resistant to icing/deicing cycles. Even after 15 icing/deicing cycles, surfaces remain hydrophobic with a static contact angle greater than 130°.

  12. Contribution a l'etude du comportement de dalles de ponts en beton arme de barres en PRF soumises a des charges concentrees simulant les charges de roues

    NASA Astrophysics Data System (ADS)

    Bouguerra, Kheireddine

    Au cours des dernieres annees, la deterioration des structures en beton arme a pris une ampleur sans precedent, et ce, malgre le fait que leur duree de vie en service initialement prevue est loin d'etre atteinte. La corrosion de l'armature d'acier est un des principaux facteurs reduisant la duree de vie des ponts en beton arme d'acier. Par ailleurs, l'armature en materiaux composites de polymeres renforces de fibres (PRF) constitue une solution a l'armature metallique afin de pallier au probleme de la corrosion d'acier et a la deterioration des structures en beton arme. Aussi, les barres d'armature en materiaux composites de PRF possedent une resistance en traction elevee (environ 2 a 6 fois la limite elastique de l'acier d'armature conventionnel), ce qui leur permet de constituer un renforcement structural attrayant pour les structures en beton. Le comportement d'elements structuraux en beton arme de barres en PRF est different de ceux en beton arme de barres d'acier. En effet, les barres en PRF possedent un module d'elasticite relativement plus faible que celui de l'acier et ont des proprietes d'adherence differentes de celles des barres d'acier. L'utilisation des barres d'armature en PRF pour armer les dalles de tabliers de ponts se concretise de plus en plus avec l'avancement des recherches dans ce domaine. La recherche entamee dans le cadre de cette these s'inscrit dans un programme de travaux realises au sein de la Chaire de recherche CRSNG/Industrie sur les Materiaux composites novateurs en PRF pour les infrastructures au departement de genie civil a l'Universite de Sherbrooke. Le comportement de membrures en beton arme de PRF soumis a des sollicitations mecaniques constitue un des principaux axes de recherche. Dans le cadre de cette these, une serie d'essais a ete effectuee sur huit dalles de ponts a confinement interne a grande echelle. Les parametres des essais comprennent: (1) l'epaisseur de la dalle, (2) le type et le taux d'armature transversale de l'assemblage inferieur, (3) la resistance en compression du beton, et (4) le taux d'armature dans les autres directions (armatures transversale et longitudinale de l'assemblage superieur et l'armature longitudinale de l'assemblage inferieur). Lors des essais de chargement, les dalles ont ete supportees par deux poutrelles metalliques espacees de 2000 mm centre a centre et soumises a une charge statique concentree sur une aire de contact de 600 mm x 250 mm afin de simuler une charge de camion (87,5 kN--CL-625) et ce conformement au code Canadien sur le calcul des ponts routiers [CAN/CSA-S6-06]. Aussi, une analyse numerique du comportement des dalles testees sous charges est faite a l'aide d'un logiciel d'elements finis ADINA version 8.2. Les essais ont montre que toutes les dalles testees ont rompu par poinconnement, peu importe le parametre etudie. Aussi, une epaisseur de dalle de 175 mm repond aux exigences du Canadien sur le calcul des ponts routiers [CAN/CSA-S6-06]. Par ailleurs, les resultats ont montre que la resistance en compression du beton est un parametre qui influe sur la deflexion, les deformations dans les barres et l'ouverture de fissures. Enfin, les resultats des analyses numeriques effectuees corroborent avec ceux obtenus experimentalement. Mots cles. Dalle de ponts en beton, armature de PRF, charges statiques, flexion, deformations, poinconnement, elements finis.

  13. Canadian Journal for the Study of Adult Education = la Revue canadienne pour l'etude de l'education des adultes. 1987-1994.

    ERIC Educational Resources Information Center

    Canadian Journal for the Study of Adult Education, 1994

    1994-01-01

    These 17 issues include feature articles and perspectives on the study of adult education, as well as book reviews/recensions of works related to adult education. Some articles are written in English, and some are written in French. Among the feature articles included are the following: "The Fifties: Pivotal Decade in Canadian Adult…

  14. Home Economics/Family Studies Curricula in Canada: Current Status and Challenges = Programmes d'etudes en economie familiale et sciences familiale au Canada: Situation actuelle et enjeux.

    ERIC Educational Resources Information Center

    Peterat, Linda; Khamasi, Jennifer

    1996-01-01

    Replicating a 1984 study, a survey of home economics/family studies coordinators in the 10 Canadian provinces found the following: home economics has expanded into grades lower than 8; required courses have increased; core curriculum has not changed radically; there is increased focus on family well-being; and there is a need to address curriculum…

  15. Etude des phenomenes chimiques au contact entre le bloc cathodique et la barre collectrice d'une cellule d'electrolyse d'aluminium

    NASA Astrophysics Data System (ADS)

    Lebeuf, Martin

    La production d'aluminium est une industrie importante au Québec. Les propriétés de ce métal le vouent à de multiples usages présents et futurs dans le cadre d'une économie moderne durable. Toutefois, le procédé Hall-Héroult est très énergivore et des progrès demeurent donc nécessaires pour en diminuer les coûts financiers et environnementaux. Parmi les améliorations envisageables de la cellule d'électrolyse se trouve le contact entre la cathode et la barre collectrice, qui doit offrir une faible résistivité au passage du courant électrique. En cours d'opération de la cellule, ce contact a tendance à se dégrader, générant des pertes énergétiques significatives. Les causes de cette dégradation, pouvant provenir de phénomènes chimiques, thermiques, mécaniques et/ou électriques, demeurent mal comprises. Le but du présent projet était donc d'étudier les phénomènes chimiques se produisant au contact bloc-barre de la cellule d'électrolyse Hall-Héroult. En premier lieu, un aspect crucial à considérer est la pénétration du bain électrolytique dans la cathode, car des composés de bain atteignent éventuellement la barre collectrice et peuvent y réagir. A cet effet, une méthode novatrice a été développée afin d'étudier les cathodes et la pénétration du bain dans celles-ci à l'aide de la microtomographie à rayons X. Cette méthode rapide et efficace s'est avérée fort utile dans le projet et a un potentiel important pour l'étude future des cathodes et des phénomènes qui s'y produisent. Ensuite, une cellule d'électrolyse rectangulaire à petite échelle a été développée. Plusieurs phénomènes observés 'en industrie sur des autopsies de cellules post-opération et rapportés dans la littérature ont été reproduis avec succès à l'aide de cette cellule expérimentale. Puis, des tests sans électrolyse, ciblant l'effet du bain électrolytique sur l'acier, ont aussi été conçus et complétés afin de ségréger l'influence des différents paramètres en jeu. L'analyse des résultats de l'ensemble de ces tests a permis de constater différents phénomènes au contact bloc-barre, dont la présence systématique de NaF et, surtout, de β-Al 2O3. Outre la carburation inévitable de la barre collectrice, la formation d'une couche Fe-Al a aussi été observée, favorisée par une pénétration rapide du bain électrolytique dans la cathode ainsi que par une composition de bain acide en surface de la barre. Cette couche comportait par ailleurs des cristaux de β-Al 2O3 pouvant nuire à sa conductivité électrique. Ensuite, à des ratios de bain entre 2.5 et 4.9, une mince couche contenant les éléments Al et N peut se former en surface de la barre. Pour un bain très basique (> 6.0), c'est plutôt une couche Na 2O qui a été observée. En conditions d'électrolyse mais sans une pénétration rapide du bain dans la cathode, du Na a pu carrément pénétrer dans la barre collectrice, préférentiellement avec le carbone. De plus, de la corrosion ainsi que des couches de fer et d'oxyde de fer peuvent se former sur la barre et potentiellement dégrader la qualité du contact électrique. Pour la suite des travaux, des mesures de résistivité ainsi que l'analyse des échantillons industriels permettraient d'évaluer l'impact de ces phénomènes sur la qualité du contact. Mots-clés : Électrolyse, aluminium, Hall-Héroult, interface barre-cathode, bain électrolytique.

  16. Etude experimentale de quelques strategies d'apprentissage d'une langue etrangere par des adultes (Experimental Study of Some Learning Strategies in Adult Second Language Learning)

    ERIC Educational Resources Information Center

    Py, Bernard

    1976-01-01

    The intermediate competence of adult second language learners is qualitatively different from native speaker competence. Learning strategies are constants in the diachronic modifications of learner competence. A study of the acquisition of interrogatives in French reveals limited strategies and the heterogeneity of linguistic models needed to…

  17. Etude de l'apprentissage par la lecture d'etudiants en contexte d'apprentissage par problemes (APP) (A Study of Student Text-Learning Strategy).

    ERIC Educational Resources Information Center

    Cartier, Sylvie

    2002-01-01

    Examined strategies reported by students during reading to develop knowledge in their area of professional training. Discovered the reading, encoding, self-regulation, and resource management strategies used most often by students, which were not sufficient to attain effective learning. Less frequently used strategies added nuances to the…

  18. La Parabole du Gaucher et de la Casserole a Bec Verseur: Etude des Processus d'Apprentissage dans un Environnement de Calculatrices Symboliques.

    ERIC Educational Resources Information Center

    Trouche, Luc

    2000-01-01

    Discusses the problems of conceptualization of the function limit in technological environments (principally graphing calculators today and symbolic calculators tomorrow) that are gradually being adopted in precalculus teaching. Explains how the instrumentation process and the conceptualization process are dependent on each other. Sets forth a…

  19. Rotary-Balance Testing for Aircraft Dynamics (Les Essais sur Balance Rotative pour l’Etude de la Dynamique du Vol de l’Avion)

    DTIC Science & Technology

    1990-01-01

    and last trigger impulse by using: - Arithmetic averaging - Fourier analysis - Regression analysis 3 6.3 Test Procedures It is possible to prepare a...trigger ImueuS by -aritirttc otaa value Q ~ - Fourier aoalYSI R egreSSIosaIYS IS 7 Figure 3-46. Measuring procedure, DFVLR apparatus- BEARING HOUSING...sampling points per test. A low pass filter with a fast Fourier transform elminiates tire structural noise at frequencies higher than those within tire

  20. Etude des magnétites dopéesa`la chaux: Substitution du fer par le calcium en site tétraédrique

    NASA Astrophysics Data System (ADS)

    G´rardin, R.; Bonazebi, A.; Millon, E.; Brice, J. F.; Evrard, O.; Sanchez, J. P.

    1989-01-01

    A 1200°C, par réaction entre solides, il est possible de dissoudre partiellement le ferrite monocalcique CaFe 2O 4 dans la magnétite Fe 3O 4. Le taux maximum de substitution du cation Fe 2+ par le cation Ca 2+ est de 20% atomique. Dans la solution solide de type spinelle, les ions Ca 2+ se placent presque exclusivement en site tétraédrique. Cette distribution cationique est confirmée par l'analyse des propriétés radiocristallographiques, spectrométrie Mössbauer du 57Fe et des propriétés magnétiques.

  1. Canadian Mathematics Education Study Group = Groupe Canadian d'Etude en Didactique des Mathmatiques. Proceedings of the Annual Meeting (Burnaby, British Columbia, Canada, May 25-29, 1990).

    ERIC Educational Resources Information Center

    Quigley, Martyn, Ed.

    These conference proceedings include two invited lectures, three working group reports, three topic group reports, two Ad Hoc group reports, a round table report, a list of participants, and a list of previous proceedings. The invited lectures were: "Values in Mathematics Education" (Ubiratan D'Ambrosio) and "Remarks on…

  2. Patch test reactions to mite antigens: a GERDA multicentre study. Groupe d'Etudes et de Recherches en Dermato-Allergie.

    PubMed

    Castelain, M; Birnbaum, J; Castelain, P Y; Ducombs, G; Grosshans, E; Jelen, G; Lacroix, M; Meynadier, J; Mougeolle, J M; Lachapelle, J M

    1993-11-01

    We performed patch tests with Dermatophagoides pteronyssinus (Dp) antigens from 2 different sources in 355 non-randomly selected patients with atopic dermatitis (AD) and 398 subjects of a control group. The study demonstrated that contact sensitization to mites occurred in an appreciable % of AD cases (20.8%), using commonly available assay products. The differences recorded between the 2 materials tested were related to the concentration of P1 antigen. Non-atopic patients rarely showed positive reactions to Dp (0.75%), when strict criteria for readings were applied and if 2 readings were performed. Patients with positive patch tests did not necessarily show positive immediate skin tests. It would be useful to carry out tests systematically in atopic patients, even if it is not yet known what modern treatment would be best for the patient. Laboratories still do not provide standardized house dust mite preparations--measuring and codifying their biological activity--for use in patch tests. It is to be hoped that the extension of this type of test will lead to the production of better test materials, in syringes with homogeneous dispersion and concentration.

  3. Etude de la degradation des refractaires aluminosiliceux par abrasion, chocs thermiques et corrosion par l'aluminium: Correlation et interaction des mecanismes

    NASA Astrophysics Data System (ADS)

    Ntakaburimvo, Nicodeme

    Aluminosilicate refractories used for melting and holding furnaces on which the present work was focused are submitted to mechanical abuse such as abrasion, mechanical impact and erosion, on one hand; and to chemical degradation by corrosion, as well as to thermal stresses, mostly due to thermal shocks; on the other hand. This thesis is focused on four main objectives. The first one is related to the designing of an experimental set-up allowing abrasion testing of refractories. The second deals with the separate study of the deterioration of aluminosilicate refractories by abrasion, thermal shock and corrosion. The third is the correlation between these three mechanisms while the fourth is related to the interaction between thermal shock and corrosion. One of the contributions of this thesis is the realisation of the above mentioned experimental set-up, which permits to carry out refractories abrasion testing, as well as at room and high temperature, in the absence or in the presence of molten metal. The fact of testing refractory resistance when it is submitted separately and simultaneously to the action of dynamic corrosion, erosion and abrasion leads to the studying of the influence of each of these three mechanisms on the other. One of the characteristics of the designed set-up is the fact that it allows to adjust the seventy testing conditions according to the mechanical resistance of the test material. The other important point is related to the fact the abrasion tests were carried out in such manner to permit degradation quantification, otherwise than by the traditional method of loss of weight measurement; particularly by measuring the wear depth and the residual material properties, such as the rupture force and the strength. A perfect correlation was observed between the wear depth and the loss of weight, both being negatively correlated with the residual rupture force. The abrasion resistance was found to be globally positively correlated with the original mechanical material's properties such as the modulus of rupture, the toughness and the elastic modulus. However, for same mechanical resistance for bricks and castables, the latter were more degraded because of more microstructural defects they contain. Moreover, in case of the castables, the original surface facing the mould was more abraded than a rectified surface because of the segregation phenomenon. It has been shown in this study that the abrasion process has no longer effect on material's strength unless the cracks length it promotes is higher than that of the initial defects. (Abstract shortened by UMI.)

  4. La detection des cyanobacteries en milieu lacustre par l'etude des anomalies des spectres de reflectance de l'eau

    NASA Astrophysics Data System (ADS)

    Constantin, Gabriel

    Proliferation of cyanobacteria is a growing problem in lacustrine environment that results in rapid degradation of water quality. Moreover, certain cyanobacteria species produce harmful toxins. Phycocyanin (PC) is a photosynthetic pigment typical of cyanobacteria and affects the water color: it is therefore possible to study them using remote sensing. At least three algorithms to estimate PC concentration ([PC]) have been published, but their relative errors are important, especially for lower concentration. In this study, we are presenting the results of a new algorithm that uses the second order variability (anomalies) of water's reflectance spectrum to estimate [PC]. This method has never been used in lacustrine environment. The dataset used to develop and validate the algorithm was obtained between 2001 and 2005 in 57 different lakes and reservoirs of the Netherlands and Spain. The performance of the second order algorithm is equivalent or better than the three previously published algorithms. For the subset were [PC] > 32 mg m-3, the contribution of the second order term (R2=0.68 and RMSE=0.25) seems to improve considerably the first order algorithm (R2=0.50 and RMSE=0.35). The accuracy of the second order algorithm for [PC] > 32 mg m-3 is superior to the one calculated for the whole dataset (R2=0.69 and RMSE=0.44). The algorithm can also be adapted to the. bands of satellite sensor MERIS for the study of cyanobacteria. The application of this algorithm to a MERIS image acquired the 29 August 2010 taken over the Missisquoi Bay (Quebec, Canada) demonstrates the potential of this new algorithm for a future cyanobacteria' monitoring system. Note that all the statistical results presented above are for the logarithm of [PC] and the units of the RMSE are log(mg/m 3).

  5. Etude des lois de comportement a haute temperature en ``plasticite-fluage'', d'un acier inoxydable austenitique (12 17 SPH)

    NASA Astrophysics Data System (ADS)

    Delobelle, P.; Oytana, C.

    1986-07-01

    De façon à compléter une étude antérieure portant sur le fluage à haute température d'un acier inoxydable austénitique du Type 316 (12-17 SPH) et afin de comprendre les relations de couplage qui existent entre les grandes déformations quasiment indépendantes du temps (plasticité) et les petites déformations souvent trés lentes (viscoplasticité), toujours intimement liées pour cet alliage, nous avons réalisé différents essais à vitesse imposée: traction, traction-compression, torsion-alternée., Durant ces essais nous avons estimé l'ordre de grandeur de la contrainte visqueuse σzz = σv par la méthode de la relaxation inverse. De façon à révéler clairement les effets liés intrinsèquement au temps avons réalisé différentes séquences de vieillissement après écrouissage. Pour intégrer et décrire l'ensemble des phénonèmes observés, nous proposons un modèle unifié dont les caractéristiques principales sont les suivantes: (i) Unicité de l'équation d'état viscoplastique: ɛ = f¦σ - α¦, avec f fortement non linéaire, ce qui permet de traduire les effets dépendant et quasiment indépendant du temps. (ii) La distinction entre grande et petite déformations s'effectue à l'aide d'un critére de charge, active ou passive, portant sur la variable α. (iii) Dans l'état de microviscoplasticé, on a α = α1, tel que α 1 présente un fort coefficient d'écrouissage h0. Dans le cas inverse, on décompose α selon α = α1 = α2 + Y et tel que les coefficients d'écrouissage vérifient: H1 + Hα2 ≪ hα1 . (iv) L'effet du temps, permettant d'atteindre l'écoulement stationnaire, indifférent à l'état du système, est pris en compte par les termes de restauration dans les lois d'évolution des variables internes. On présente quelques simulations, réalisées avec le modèle développé, pour différents types de sollicitations.

  6. Etude et modelisation du frittage de pieces moulees par injection de poudres metalliques d'acier inoxydable et de superalliage de nickel

    NASA Astrophysics Data System (ADS)

    Ste-Marie, Michael

    Stainless Steel and Superalloy parts have been obtained by Maetta metal injection molding process to understand the sintering and to build a model of the shrinkage and the density by DOE after sintering. Maetta process consists of low pressure injection molding; this technology is competitive for medium series and complex geometries. The experimental procedure shows how to reduce the dimensions variability and to optimise the cost and the mechanical properties for the chosen alloys on Maetta equipments. The parts have been injected with a Maetta mixer and pneumatic presses. After that, the binder removal was done by capillary debinding. All sintering have been managed following a design of experiment (DOE) plan. The results of density measured by the Archimede's method and shrinkage were obtained by a regression model as a function of final heating ramp, soaking temperature and time. The simulation predicts experimental results with a relative error of 0,25% on the density and 2,2% for the shrinkage. The model is a good way to begin a complete simulation that regroups all effects on the dimensions of sintered parts for the Maetta process. The effects of the geometry, powder characteristics and debinding step on density and dimensions after sintering are not added in this study. Other studies would be necessary to build a global simulation.

  7. etude experimentale de la propagation de fissures de fatigue dans la zone affectee thermiquement de joints soudes de roues de turbines hydrauliques

    NASA Astrophysics Data System (ADS)

    Trudel, Alexandre

    This thesis presents the results of a comprehensive experimental study on the fatigue crack propagation behavior in aqueous environment of the heat affected zone of CA6NM stainless steel hydraulic turbine runner welds. The initial objective of this project was to determine the fatigue crack growth properties of the heat affected zone. To achieve this, standardized fatigue crack growth tests in aqueous environment were performed to determine the crack growth threshold DeltaKth, and the Paris relationship constants C and m of the heat affected zone. Given potential experimental uncertainties arising from the growth of a crack confined to the heat affected zone, fatigue crack growth tests in an aqueous environment at constant stress intensity factor range (DeltaK) were performed so that the crack would propagate across the heat affected zone. These tests allowed to better appreciate the fatigue crack growth resistance variation between the three zones of the weld, i.e., the filler metal, the heat affected zone and the base metal. Various experimental objectives were supplemented to these two primary objectives. A CA6NM plate was welded to generate a layer of filler metal over its entire surface. The welded plate was cut in two equal pieces, one of which was post-weld heat treated in order to study the effect of this treatment on the fatigue crack growth behavior. Compact tension type fatigue specimens were machined from the welded plates. Rectangular samples were also collected to allow the characterization of the weld. Metallographic observations and X-ray diffraction measurements of the three zones of the weld (filler metal, heat affected zone and base metal) were conducted in order to characterize the microstructure. This microstructural characterization combined with metallographic observations of the crack path profiles were useful in assessing the microstructural effects acting on the fatigue crack growth behavior of the weld. Microhardness measurements were carried out across the weld in order to quantify the heat affected zone width and to allow a relative mechanical characterization of the three weld zones. Residual stresses were measured in fatigue specimens to determine their influence on the fatigue crack growth behavior. Finally, the fracture surfaces were observed using a scanning electron microscope in order to identify the main fracture mechanisms. This work led to several conclusions about the fatigue crack growth behavior in aqueous environment of hydraulic turbine runner welds, and especially in the heat affected zone. First, the measured crack tip tensile residual stresses inhibited crack closure, which resulted in a deteriorated resistance to fatigue crack growth. On the other hand, the beneficial effect of post-weld heat treatment was explained by its ability to sufficiently reduce the tensile residual stresses to allow crack closure to occur. Secondly, the martensitic microstructure of the three weld zones was identified as influencing the fatigue crack growth behavior. The varying martensite coarseness between the three weld zones influenced the path of the crack. A fine martensitic microstructure, as observed in the weld metal, resulted in a linear crack path, while a coarse microstructure, as observed in the heat affected zone and base metal, resulted in a tortuous crack path. The degree of crack path tortuosity was related to the fatigue crack growth resistance, which revealed that a coarse martensitic microstructure that leads to a tortuous crack path, promotes toughening by local mixed modes of crack advance and roughness-induced crack closure. Thirdly, when the crack propagated in the heat affected zone, a tendency to gradually deviate towards the base metal was observed. This behavior was rationalized by considering the yield strength mismatch between the three weld zones. The yield strength decreased in the heat affected zone from filler metal to base metal. Finally, the presence of residual and/or reformed austenite in the three zones of the weld, as well as the occurrence of an intergranular fracture mechanism in the heat affected zone and base metal were identified as having a negligible influence on the fatigue crack growth behavior in the amounts measured. The main conclusion of this study is that the heat affected zone is only slightly less resistant to fatigue crack growth than the base metal. This was attributed to its somewhat finer microstructure that leads to a less tortuous crack path. It is rather the weld-induced residual stresses that dominantly affect the growth of fatigue cracks in hydraulic turbine runner welds. From a practical point of view, the results of this research allow to assert that the turbine runner welding process combined with a post-weld heat treatment produce a weld with good resistance to fatigue crack growth. (Abstract shortened by UMI.).

  8. Etude calorimétrique et structure cristalline du putrescinium monohydrogénomonophosphate dihydrate NH 3(CH 2) 4NH 3HPO 42H 2O

    NASA Astrophysics Data System (ADS)

    Kamoun, Slaheddine; Jouini, Amor

    1990-11-01

    Chemical preparation, calorimetric studies, and crystal structure are given for a new monophosphate. The putrescinium monohydrogen monophosphate dihydrate salt is monoclinic with the unit cell dimensions a = 6.541(1) Å, b = 16.648(3) Å, c = 9.175(1) Å, β = 95.74(1)°, V = 994.1(5) Å 3, Dm = 1.498 Mgm -3, Dx = 1.484 Mgm -3, μ = 2.732 mm -1, space group {P2 1}/{c} with Z = 4. The structure was solved by the Patterson method and refined to a final value of 0.046 for 1732 observed independent reflections. The structure shows a layer arrangement perpendicular to the overlinec axis: planes of the [HPO 4] 2- tetrahedra alternate with planes of the [(CH 2) 4(NH 3) 2] 2+ dication. The zeolitic water molecules are located between these planes separated by a distance of 2.294 Å. The monohydrogen phosphate group is roughly tetrahedral with the symmetry 3 m. The PO distances in this group range from 1.495(2) to 1.592(2) Å. The amino groups of putrescine are protonated. The putrescinium dication has an extensive all- trans configuration with a noncrystallographic inversion center. The cohesion and the stability of the atomic arrangement result from three kinds of hydrogen bonds, NH····O, POH····O(w), and O(W)H····O. The differential scanning calorimetric study shows that the dehydration of this salt occurs in two steps respectively at 105 and 121°C with a loss of one water molecule per step. The anhydrous salt undergoes four phase transitions respectively at temperatures of 133, 143, 159, and 165°C.

  9. Identification d'indicateurs de risque des populations victimes de conflits par imagerie satellitaire. Etude de cas: Le nord de l'Irak

    NASA Astrophysics Data System (ADS)

    Mubareka, Sarah Betoul

    Remote sensing and security, terms which are not usually associated, have found a common platform this decade with the conjuring of the GMOSS network (Global Monitoring for Security and Stability), whose mandate is to discover new applications for satellite-derived imagery to security issues. This study focuses on human security, concentrating on the characterisation of vulnerable areas to conflict. A time-series of satellite imagery taken from Landsat sensors from 1987 to 2001 and the SRTM mission imagery are used for this purpose over a site in northern Iraq. Human security issues include the exposure to any type of hazard. The region of study is first characterised in order to understand which hazards are and were present in the past for the region of study. The principal hazard for the region of study is armed conflict and the relative field data was analysed to determine the links between geographical indicators and vulnerable areas. This is done through historical research and the study of open-sourced information about disease outbreaks; the movements of refugees and the internally displaced; and humanitarian aid and security issues. These open sources offer information which are not always consistent, objective, or normalized and are therefore difficult to quantify. A method for the rapid mapping and graphing and subsequent analysis of the situation in a region where limited information is available is developed. This information is coupled with population numbers to create a "risk map": A disaggregated matrix of areas most at risk during conflict situations. The results show that describing the risk factor for a population to the hazard conflict depends on three complex indicators: Population density, remoteness and economic diversity. Each of these complex indicators is then derived from Landsat and SRTM imagery and a satellite-driven model is formulated. This model based on satellite imagery is applied to the study site for a temporal study. The output are three 90 m x 90 m resolution grids which describe, at a pixel level, the risk level within the region for each of the dates studies, and the changes which occur in northern Iraq as the result of the Anfal Campaigns. Results show that satellite imagery, with a minimum of processing, can yield indicators for characterising risk in a region. Although by no means a replacement for field data, this technological source, in the absence of local knowledge, can provide users with a starting point in understanding which areas are most at risk within a region. If this data is coupled with open sourced information such as political and cultural discrimination, economy and agricultural practices, a fairly accurate risk map can be generated in the absence of field data. Keywords. SRTM, Landsat, risk indicators, Iraq, conflict, population vulnerability, segmentation, land-use, fuzzy-classification, atmospheric corrections.

  10. Etude numerique de l'effet de l'elancement et de la garde au sol Sur le galop d'un corps rigide cylindrique a section carree

    NASA Astrophysics Data System (ADS)

    Corbeil-Letourneau, Simon

    In this thesis, the transverse galloping of square cylinders is investigated in 3D by means of a fully coupled fluid-structure interaction numerical model. More precisely, the in uence of two parameters: the aspect ratio and the presence of a gap or not are investigated. Before performing the investigation by means of 3D simulations one of the main issue to overcome is the high cost of 3D direct simulation. An important part of this cost is due to the management of the deformations of the mesh that must follow the moving body. The pseudo-solid method is a strategy to manage the deformations but it involves solving additional equations which double the number of unknowns. The use of this method have been avoided by solving the Navier-Stokes equations and the rigid body equations in the non-inertial frame of the moving body. In this frame the body is fixed, then there is no need to deform the mesh, but this comes with the side effect of an addition of fictitious force that act on the body. Because we need the force calculated in the fixed frame of the laboratory, we need to deduce the real force acting on the body. This is done by removing the fictitious force and by adjusting the mass of the body. In summary, the change of referential allows us to solve the equations at lower cost because there is no need to deform the mesh. The new. The new method has been validated on number of test cases obtained form the scientific literature. This validation have been successful and allowed us to be sure that the code solved the equations properly. Then the 3D direct simulations have been carried out to investigate the effect of aspect ratio. The analysis of the resulting data shows that the aspect ratio have weak effect on the amplitude of galloping. In other words, the effect of aspect ratio is not critical and can not explain the differences between experimental data and 2D simulations. Then, the next step have been realized, the investigation of the effect of gap below the cylinder have been carried out. This time, the analysis of data have shown that the effect on galloping is critical and play a central role in the differences already described. It has been found that there is a critical value of gap above which the inhibited galloping reappear. This means that normally, in the situation of an infinite cylinder (which situation is the 3D analog of 2D simulation), the galloping can't develop but if a sufficiently large gap is added the galloping can appear. So we conclude that the gap is the parameter that explains the difference between the galloping observed experimentally at low mass ratio and its inhibition in 2D simulations. The analysis have been pushed further. We have found that in presence of a gap, the Von Karman vortex (responsible of VIV) are formed further in the wake of the cylinder. This explains why the VIV interact less with the galloping. The flow structure involved in this phenomenon has also been identified, it's an hairpin vortex that is formed by the collision of the flow passing through the gap and an opposite flow induced by the Von Karman vortex. In summary, the question is partially answered, we know that the gap is the dominant parameter which allow the galloping to be sustained in 3D at low mass ratio. An hairpin vortex keeps away from the body the Von Karman vortex. This distance mitigates the strong interactions with the body which usually inhibit galloping in 2D at low mass ratio. But it's still not known what is the effect of the high Reynolds numbers involved in experiments. (Abstract shortened by UMI.).

  11. The Relationship between Musical Instrumental Performance Skills and Postsecondary Musical Independence (How Important Are Scales, Etudes, Solos, Sight-Reading, Improvisation, Etc.?)

    ERIC Educational Resources Information Center

    Bobbett, Gordon C.; And Others

    This study examines the relationships among a variety of secondary/postsecondary experiences and activities and postsecondary students' musical independence (MI). The paper reports on the impact Instrumental Performance Skills (IPSs) have on the students" MI development during private lessons, band rehearsal, and individual practicing. The study…

  12. Etude structurale par RMN 29Si—V. Dérivés de la quinoléine et de l'isoquinoléine

    NASA Astrophysics Data System (ADS)

    Grignon-Dubois, M.; Fialeix, M.; Laguerre, M.

    A series of silylated compounds obtained from quinoline or isoquinoline were studied by 29Si NMR using the selective polarization transfer (SPT). Both silicon chemical shifts and 29Si, 1H coupling constants have been measured. These results are the first example of coupling through siliconnitrogen bonds.

  13. Etude du comportement sous charges laterales des ossatures de beton arme avec murs de remplissage de maconnerie, construites avant les annees 1960

    NASA Astrophysics Data System (ADS)

    Lefebvre, Karine

    Reinforced concrete structures with unreinforced masonry infills (BMR) are considered vulnerable to earthquakes. Under seismic actions, infills could fail (causing injuries or death) and cause damages to columns. In Quebec and Canada, most of BMR structures have been constructed prior to the introduction of modern seismic design codes raising question on the contribution of the infill to the structure lateral resistance. The aim of this thesis is to improve modelling technique of BMR structures built in Quebec between 1915 and 1960. This type of structures is found in hospitals or schools buildings, which must comply with some post-earthquake functionality requirements. They could also be residential or office buildings. Actually, practicing engineers usually calculate seismic capacity of BMR structures without considering the infill's structural contribution to the lateral resistance. Yet, this contribution should not be omitted. The first part of the thesis investigates the construction techniques and material properties of the old BMR structures in the Province. The results are the material properties (concrete, reinforcing steel, brick, terra cotta tile, and mortar) and the characteristics of the assemblies (wall section, reinforcement details…). The second part of the thesis presents the results of series of parametric analyses to identify among modelling and geometric parameters, which ones are the most influent on the lateral load response (rigidity, fundamental period, normal modes). Linear and modal analyses were performed. The most influent parameters identified are: number of storeys, number of bays, bay's width, soft storey, openings, upper storeys modelized (instead of being replaced by punctual loads) and the modelization technique of infills panels (strut or shell). Nonlinear static analyses have been performed to identify the most influent parameters to be considered for evaluating the lateral resistance, the capacity (load / displacement) and the yielding sequence (beam versus columns versus infills). The identified parameters are the presence of the infills, the openings and the geometric characteristics of the models (number of storeys and number of bays). One important contribution of this work is the development of an equivalent strut model to represent the action of the infill. The model could be easily implemented in standard analysis software. A central axial hinge reproducing the nonlinear behaviour of the masonry is added to the strut element. This model is a hybridization of existing proposals (FEMA and others) with added innovations by the author. It has been validated with experimental and numerical analyses results from literature. An important conclusion of this thesis is that the contribution of infills to lateral load resisting capacities of BMR structures should be considered for structure of more than one storey. Infills can add up to 51 % to bare frame capacity. The National building code requires that the lateral resistance of existing buildings must be at least 60 % of the equivalent static seismic force (V2005). It is concluded that one storey BMR buildings have a sufficient resistance, while three-storeys structures exhibit plastic deformations for loads under 0,6* V2005.

  14. Etude échographique du diamètre de l'enveloppe du nerf optique chez l'enfant noir africain sain

    PubMed Central

    de Tové, Kofi-Mensa Savi; Biaou, Olivier; Adedemy, Julien Didier; Fatigba, Olatoundji Holden; Yèkpè, Patricia; Boco, Vicentia; Agossou-Voyeme, Augustin Karl

    2014-01-01

    Introduction L'objectif de cette étude était de déterminer le diamètre échographique de l'enveloppe du nerf optique (DENO) dans une population d'enfants sains noirs Africains au Bénin. Méthodes Une étude transversale descriptive a été menée sur une période de 6mois. Le DENO a été mesuré chez 304 enfants sains. Deux mesures échographiques du DENO (coupe transversale et sagittale) ont été réalisées 3mm en arrière de la papille sur chaque œil. Le DENO d'un patient est égal à la moyenne des quatre mesures. Résultats L’âge moyen était de 35, 72 ± 35,38 mois et la sex-ratio H/F de 0,96. La mesure moyenne du DENO était de 3, 31±0,54mm avec des extrêmes de 2,02 et de 4,44mm. Le DENO croît avec l’âge avec une moyenne corrélation significative (r = 0,58 et p < 0,0001). Cette croissance est plus marquée pendant les 48 premiers mois de vie. Il n'y avait pas de différence entre les garçons et les filles (p = 0, 45). Conclusion Les valeurs retrouvées dans cette étude ne diffèrent pas de ce qui est classiquement décrit dans les autres populations. Un DENO supérieur à 4,40 (IC 95%) doit être considéré comme anormal. PMID:25870740

  15. Etude de la cinétique de polarisation de concentration en microfiltration du sang en régime transitoire

    NASA Astrophysics Data System (ADS)

    Ding, L. H.; Laurent, J. M.; Jaffrin, M. Y.

    1994-12-01

    In plasma separation by membrane, the blood flows tangentially along a microporous membrane while the plasma crosses the membrane under the action of a transmembrane pressure gradient. As in other cross flow filtrations of suspensions, the permeate flux increases linearly at low transmembrane pressure and reaches a plateau at high transmembrane pressure due to concentration polarization and membrane fouling. Concentration polarization consists in the formation of a high particle concentration boundary layer near the membrane which is assumed to occur rapidly, in less than one minute. In the case of plasma filtration from blood, this layer consists of cells which are rejected by the membrane and it forms a reversible secondary membrane which becomes the limiting filtration mechanism. In this condition, the permeate flux becomes approximately independent of transmembrane pressure and is controlled mostly by the shear rate. In order to study the kinetics and time scales of establishment of these phenomena, we have investigated the transient response of microporous membrane under stepped charges in transmembrane pressure. When the pressure is suddenly raised from the unpolarized regime to a level corresponding to complete concentration polarization, the permeate flux reaches a peak in 0.4-0.6s, which surpasses the equilibrium level by 60 to 80% depending upon the pressure, returning to the concentration polarization equilibrium level in 3 to 4s. These data show that the membrane retains its original permeability only during the first 0.5s of the pressure change and that concentration polarization takes about 3 to 4s to build-up. This formation time decreases with increasing pressure. When the pressure returns to its initial level, the concentration polarization disappears instantaneously and the process can be repeated at a frequency up to 0.7Hz. However, when a stepped pressure increase is applied in the concentration polarization regime, with initial pressure above 150mmHg, the permeate flux hardly changes, which confirms that once concentration polarization is established, the system membrane-polarization layer ceases to behave as a porous medium even with increased resistance. These data can explain the permeate increase observed when pressure and flow pulsations at 1Hz are superimposed on the retentate. La plasmaphérèse par membrane consiste à filtrer le plasma au travers d'une membrane microporeuse sous l'action de la pression transmembranaire. Comme toutes filtrations tangentielles, le flux de filtration augmente linéairement aux faibles pressions transmembranaires, puis atteint un plateau aux fortes pressions à cause du phénomène de polarisation de concentration et du colmatage de la membrane. La polarisation de concentration est due à la formation d'une couche fortement concentrée en soluté au voisinage de la membrane. Le temps de formation de cette couche est rapide, généralement inférieur à une minute. En microfiltration du sang, cette couche est constituée des globules qui forment une seconde membrane réversible qui limite le flux de filtration. Dans ce régime, le flux de perméat devient indépendant de la pression transmembranaire et dépend principalement du taux de cisaillement. Nous avons entrepris une étude de la réponse transitoire d'une membrane à des échelons de pression transmembranaire afin de comprendre la cinétique d'établissement de ces phénomènes. Lorsque l'on passe brusquement d'un régime non polarisé à celui polarisé, le flux de filtration croît jusqu'à un pic en 0,4 à 0,6s dépassant la valeur du plateau de 60 à 80%, puis il revient à sa valeur d'équilibre correspondant au régime de polarisation de concentration en 3 à 4s. Les données expérimentales montrent que la membrane garde une perméabilité originale pendant seulement 0,5s lors d'un changement brusque de pression et que la couche de polarisation de concentration met environ 3 à 4s à s'établir. Quand la pression transmembranaire est abaissée, la couche de polarisation disparaît également et le processus peut se répéter à une fréquence de 0,7Hz. Mais, une fois le régime de polarisation de concentration atteint, la réponse de la membrane devient négligeable. Cette étude justifie le choix d'une fréquence de 1Hz employée dans notre laboratoire en plasmaphérèse membranaire à débit pulsé.

  16. Champs morphogenetiques mis en evidence par l'etude au microscope electronique a balayage des soies au niveau des pattes d'abeilles (apoidea, megachilidae).

    PubMed

    Pasteels, J M; Pasteels, J J

    1973-01-01

    The hairs covering the legs of several species of female megachilid bees are arranged in imbricated fields. At the boundaries of these fields, either the hairs show a morphology intermediate between those of the contiguous fields, or there is a narrow strip with an irregular mosaïc of several hair types. It is suggested that: 1. The structure of the hairs may be determined by the territory in which the trichogenous cell is located. 2. Some morphogenetic fields are bidimensional and cross the segmentary boundaries. The name 'regional fields' is proposed for them. 3. The regional fields may be modulated within each segment into which they extend.

  17. Canadian Mathematics Education Study Group = Groupe Canadian d'etude en didactique des mathematiques. Proceedings of the Annual Meeting (Fredericton, New Brunswick, Canada, May 23-27, 1991).

    ERIC Educational Resources Information Center

    Quigley, Martyn, Ed.

    The proceedings report is divided into four sections that include: (1) two invited lectures by Colette Laborde and James Kaput on the topics of students' reading and writing of mathematics and an allegory in which writing is introduced into a technology-based mathematical society; (2) working group reports on the topics of fractal geometry in the…

  18. Canadian Mathematics Education Study Group = Groupe Canadien d'etude en didactique des mathematiques. Proceedings of the Annual Meeting (Winnipeg, Manitoba, Canada, June 2-6, 1988).

    ERIC Educational Resources Information Center

    Pereira-Mendoza, Lionel, Ed.

    These conference proceedings include two invited lectures, four working group reports, seven reports from topic groups, one ad hoc presentation paper, a list of participants and a list of previous proceedings. The invited lectures were: "Mathematics Education and Technology" (Christine Keital); and "All One System" (Lynn A.…

  19. Canadian Mathematics Education Study Group = Groupe Canadien d'etude en didactique des mathematiques. Proceedings of the 1993 Annual Meeting (York, Ontario, Canada, May 28-June 1, 1993).

    ERIC Educational Resources Information Center

    Quigley, Martyn, Ed.

    These proceedings contain papers presented at the 1993 annual meeting of the Canadian Mathematics Education Study Group. Papers are presented in four sections: (1) invited lectures; (2) working groups; (3) topic groups; and (4) ad hoc groups. Papers include: (1) "What is a Square Root? A Study of Geometrical Representation in Different…

  20. Canadian Mathematics Education Study Group = Groupe Canadien d'etude en didactique des mathematiques. Proceedings of the 1995 Annual Meeting (Ontario, Canada, May 26-30, 1995).

    ERIC Educational Resources Information Center

    Pothier, Yvonne M., Ed.

    These proceedings contain the papers presented at the 1995 annual meeting of the Canadian Mathematics Education Study Group. Papers are organized into four sections: (1) plenary lectures; (2) working groups; (3) topic sessions; and (4) ad hoc sessions. Papers include: (1) "The Role of Epistemology in the Analysis of Teaching/Learning…

  1. Ressources de mathematiques, maternelle-12e annee: Bibliographie annotee. Cadre commun des programmes d'etudes (Pre-Kindergarten-Grade 12 Mathematics Resources: Annotated Bibliography. Common Curriculum Framework).

    ERIC Educational Resources Information Center

    Western Canadian Protocol for Collaboration in Basic Education, Edmonton (Alberta).

    This annotated bibliography identifies French language resources endorsed for the K-12 grade levels by all Western Canadian Protocol (WCP) jurisdictions implementing the Common Curriculum Framework for K- 12 Mathematics. Resources were selected through a collaborative review process based on their high level of fidelity with the rationale,…

  2. Ressources de mathematiques, Maternelle-12e annee: Bibliographie annotee. Cadre commun des programmes d'etudes (Pre-Kindergarten-Grade 12 Mathematics Resources: Annotated Bibliography. Common Curriculum Framework).

    ERIC Educational Resources Information Center

    Western Canadian Protocol for Collaboration in Basic Education, Edmonton (Alberta).

    This annotated bibliography identifies French language resources endorsed from 1990-1999 by all Western Canadian Protocol (WCP) jurisdictions implementing the Common Curriculum Framework for K-12 Mathematics for K-12 (Common Curriculum Framework). Resources in this bibliography were selected through a collaborative review process based on their…

  3. Canadian Mathematics Education Study Group = Groupe Canadien d'Etude en Didactique des Mathematiques. Proceedings of the Annual Meeting (Kingston, Ontario, Canada, May 29-June 2, 1987).

    ERIC Educational Resources Information Center

    Mendoza, Lionel P., Ed.; Williams, Edgar R., Ed.

    These conference proceedings include three invited lectures, a panel discussion, three working group reports, two reports from topic groups and a participant list. The invited lectures include a discussion of the impact of calculators on the calculus curriculum (Herbert S. Wilf); a consideration of the role of misconceptions in learning…

  4. Canadian Mathematics Education Study Group = Groupe Canadien d'etude en didactique des mathematiques. Proceedings of the 1994 Annual Meeting (Regina, Saskatchewan, Canada, June 3-7, 1994).

    ERIC Educational Resources Information Center

    Quigley, Martyn, Ed.

    These proceedings contain papers from the 1994 annual meeting of the Canadian Mathematics Education Study Group. Papers are divided into the following sections: (1) invited lectures; (2) working groups; (3) topic groups; (4) ad hoc groups; and (5) reports on ICMI (International Committee on Mathematical Instruction) studies. Papers include: (1)…

  5. Non-Lethal Weapons Effectiveness Assessment Development and Verification Study (Etude d’evaluation, de developpement et de verification de l’efficacite des armes non letales)

    DTIC Science & Technology

    2009-10-01

    security of the camp and freedom of movement of own troops. Car Park Main Road 50 m Check Point fence wall no trespassing zone 10–20 m N Check Point...are our vehicles. • In line with trials data, the driver will keep his foot on the accelerator, even after the system has engaged the front tyres ...puncturing of target vehicles’ tyres , ten minutes has been allowed for the vehicle to start moving again, and it is assumed those vehicles are only capable

  6. Etude par émission acoustique de la dynamique des dislocations pendant la déformation cyclique de polycristaux d'aluminium

    NASA Astrophysics Data System (ADS)

    Slimani, A.; Fleischmann, P.; Fougères, R.

    1992-06-01

    The cyclic plasticity of 5N polycrystalline aluminium have been studied at room temperature by measuring the continuous acoustic emission (A.E.) due to dislocations movements in the metal. In this study, original data have been obtained in the understanding of continuous A.E. sources. In comparison with classical interpretation given in the literature, the fact that dislocations are arranged according to a dislocation cell structure from the first cycle has been included in the analysis of the results. From this, it has been shown that the amplitude of the A.E. signal is not directly connected with the plastic strain rate prescribed to the fatigue sample and that the probability density function of dislocation loops created during the cycling can be determined. La plasticité cyclique de l'AI 5N polycristallin a été étudiée à la température ambiante à partir de mesures d'émission acoustique continue (E.A.). L'application de la technique de l'E.A. nous a permis d'obtenir des données originales quant aux mécanismes sources d'E.A. Par rapport aux interprétations classiques de la littérature, nous avons fait intervenir le fait que, dès les premiers cycles, une structure cellulaire de dislocations est établie. Nous montrons que l'amplitude du signal d'E.A. n'est plus liée directement à la vitesse de déformation plastique macroscopique. A partir de cette donnée, l'analyse des résultats d'E.A. permet d'obtenir des informations sur la fonction distribution des boucles de dislocations créées au cours de la déformation cyclique.

  7. Etude par resistivite electrique du comportement d'un alliage amorphe Fe 40Ni 38Mo 4B 18 deforme par traction

    NASA Astrophysics Data System (ADS)

    Hoang, Long Phan; Sacovy, Paulette; Delaplace, Jean

    1983-02-01

    Des rubans d'alliages amorphes Metglas du type Fe 40Ni 38Mo 4B 18 à l'état brut de trempe ont été déformés par traction à la température ambiante et l'on a suivi les variations de la résistance électrique des échantillons au cours de la déformation. Il ressort de ces essais que la déformation plastique qui est de l'ordre de 0.5% avant rupture ne se produit pas de faĉon homogène dans l'échantillon. Les mesures électriques effectuées au cours de la déformation mettent en évidence dans le domaine élastique un effet d'élastorésistance, relativement important ( K ≠ 1); elles montrent que dans le domaine plastique la déformation permanente des échantillons s'accompagne d'une diminution de la résistivité électrique du matériau. Deux hypothèses sont discutées pour expliquer cet effet inattendu, l'un qui fait appel à l'existence de volumes libres, l'autre qui suppose une cristallisation localisée du matériau sous l'effet de la contrainte.

  8. Etude analytique du fonctionnement des moteurs à réluctance alimentés à fréquence variable

    NASA Astrophysics Data System (ADS)

    Sargos, F. M.; Gudefin, E. J.; Zaskalicky, P.

    1995-03-01

    In switched reluctance motors fed by a constant voltage source (like a battery) at high frequencies, the current becomes unpredictable and often cannot reach a given reference value, because of the variation of the inductances with the rotor position ; the “motional” m.m.f. generates commutation troubles which increase with the frequency. An optimal control as well as an approximate design of the motor require a quick and simple calculation of currents, powers and losses ; now, in principle, the non-linear electrical equation needs a numerical resolution, whose results cannot be extrapolated. By linearizing this equation by intervals, the method proposed here allows to express analytically, in any case, the phase currents, the torque and the copper losses, when the feeding voltage itself is constant by intervals. The model neglects saturation, but a simple adjustment of the inductance (chosen ad libitum) allows to deal with it. The calculation is immediate and perfectly accurate as long as the machine parameters themselves are well defined. Some results are given as examples for two usual feeding modes. Dans les machines à réluctance alimentées à haute fréquence par une source à tension constante, comme une batterie, le courant varie de manière difficilement prévisible, à cause de la variation des inductances avec la position du rotor, et souvent ne parvient pas à s'établir à une valeur de consigne imposée ; la f.é.m. “motionnelle” engendre des difficultés de communication qui s'aggravent avec l'augmentation de fréquence jusqu'à empêcher le fonctionnement. Tant pour optimiser la commande que pour dimensionner approximativement un moteur ; on doit pouvoir calculer simplement et rapidement le courant et la puissance ; or l'équation électrique, non linéaire, doit en principe être résolue numériquement et les résultats ne sont pratiquement pas extrapolables. En linéarisant par intervalles cette équation, la méthode proposée ici permer d'exprimer analytiquement et dans tous les cas les courants de phase, la puissance fournie et les pertes Joule, lorsque la tension aux bornes de l'enroulement est constante par morceaux. Le modèle utilisé néglige la saturation ; mais il est possible de tenir compte de celle-ci par des ajustements, facilement calculables, de la courbe d'inductance, quelle que soit son allure. Les calculs sont immédiats et parfaitement précis pour autant que les paramètres soient bien définis. Quelques résultats sont donnés à titre d'exemple, pour deux modes d'alimentation usuels.

  9. Adult Literacy: Policies, Programs and Practices. Lessons Learned. Final Report = Alphabetisation des adultes: politiques, programmes et pratiques. Etude bilan. Rapport final.

    ERIC Educational Resources Information Center

    2001

    Studies and reports examining the problems associated with adult literacy and efforts to address those problems were reviewed to identify lessons for adult literacy programs in Canada and elsewhere. Low literacy levels were linked to above-average rates of personal and/or learning difficulties, low self-esteem, associated social problems, and…

  10. Etude de l'influence du champ magnetique dans une section d'essais thermohydraulique d'un canal de reacteur nucleaire CANDU 6

    NASA Astrophysics Data System (ADS)

    Landry-Lavoie, Renaud

    This memoir deals with the effects of the magnetic fields present in a thermal hydraulic test section of the Canadian nuclear industry. This test section is used to determine the thermal hydraulic conditions that can lead to critical heat flux in a channel of a CANDU 6 nuclear reactor. To perform their series of experiments the STERN Company used strong electric currents to heat the simulation bundles with a thermal power similar to the one found in a channel of a CANDU reactor. The materials constituting the simulation channel and its supports are of ferromagnetic nature. The strong magnetic field generated by the bundles implies that they are subjected to a magnetostatic force due to the magnetization of the ferromagnetic materials. The nuclear industry wants to know if these efforts, combined with the force of gravity, are sufficient to maintain the bundles in place in the simulation channel. The question also arises whether or not the magnetic field present in the channel can affect the parameters of boiling heat transfer. To determine the magnetic field distribution in the simulation channel, we had recourse to the magnetostatic image method and the integral method of calculation of magnetization. The results of the calculations show that the magnetostatic forces exerted by the ferromagnetic elements of the test section are inferior in magnitude to the one estimated by the STERN laboratorie. We used the mechanistic model of Sullivan et al. (1964) to evaluate the possible influence of the magnetic fields on the departure diameter of the vapor bubbles. The deviation in the frequency of bubble emission was evaluated by using the correlations of Zuber et al. (1959) and Cole (1960). By introducing a magnetostatic force in the boiling model and in the correlations, we demonstrated that the magnetic field present in the STERN test section has a negligible effect on the bubble departure diameter and their emission frequency. We conclude that the conditions in the test section are consistent with those prevailing in the channel of a CANDU 6 reactor.

  11. Higher risk of death among MEN1 patients with mutations in the JunD interacting domain: a Groupe d'etude des Tumeurs Endocrines (GTE) cohort study.

    PubMed

    Thevenon, Julien; Bourredjem, Abderrahmane; Faivre, Laurence; Cardot-Bauters, Catherine; Calender, Alain; Murat, Arnaud; Giraud, Sophie; Niccoli, Patricia; Odou, Marie-Françoise; Borson-Chazot, Françoise; Barlier, Anne; Lombard-Bohas, Catherine; Clauser, Eric; Tabarin, Antoine; Parfait, Béatrice; Chabre, Olivier; Castermans, Emilie; Beckers, Albert; Ruszniewski, Philippe; Le Bras, Morgane; Delemer, Brigitte; Bouchard, Philippe; Guilhem, Isabelle; Rohmer, Vincent; Goichot, Bernard; Caron, Philippe; Baudin, Eric; Chanson, Philippe; Groussin, Lionel; Du Boullay, Hélène; Weryha, Georges; Lecomte, Pierre; Penfornis, Alfred; Bihan, Hélène; Archambeaud, Françoise; Kerlan, Véronique; Duron, Françoise; Kuhn, Jean-Marc; Vergès, Bruno; Rodier, Michel; Renard, Michel; Sadoul, Jean-Louis; Binquet, Christine; Goudet, Pierre

    2013-05-15

    Multiple endocrine neoplasia syndrome type 1 (MEN1), which is secondary to mutation of the MEN1 gene, is a rare autosomal-dominant disease that predisposes mutation carriers to endocrine tumors. Although genotype-phenotype studies have so far failed to identify any statistical correlations, some families harbor recurrent tumor patterns. The function of MENIN is unclear, but has been described through the discovery of its interacting partners. Mutations in the interacting domains of MENIN functional partners have been shown to directly alter its regulation abilities. We report on a cohort of MEN1 patients from the Groupe d'étude des Tumeurs Endocrines. Patients with a molecular diagnosis and a clinical follow-up, totaling 262 families and 806 patients, were included. Associations between mutation type, location or interacting factors of the MENIN protein and death as well as the occurrence of MEN1-related tumors were tested using a frailty Cox model to adjust for potential heterogeneity across families. Accounting for the heterogeneity across families, the overall risk of death was significantly higher when mutations affected the JunD interacting domain (adjusted HR = 1.88: 95%-CI = 1.15-3.07). Patients had a higher risk of death from cancers of the MEN1 spectrum (HR = 2.34; 95%-CI = 1.23-4.43). This genotype-phenotype correlation study confirmed the lack of direct genotype-phenotype correlations. However, patients with mutations affecting the JunD interacting domain had a higher risk of death secondary to a MEN1 tumor and should thus be considered for surgical indications, genetic counseling and follow-up.

  12. Etude de l'impact de la valorisation energetique de pneus hors d'usage, dans une cimenterie, sur les emissions gazeuses par modelisation de la dispersion atmospherique

    NASA Astrophysics Data System (ADS)

    Bredin, Nathalie

    La génération incéssante de déchets nécessite le développement de nouvelles technologies, telle que la valorisation énergétique, pour en disposer. Une filière appropriée pour valoriser énergétiquement les déchets est le procédé cimentier. L'industrie du ciment est une des grandes consommatrices d'énergie. La température nécessaire à la préparation du ciment se situe aux environs de 1450°C pour faire réagir la matière première (cru) qui est sous forme poudreuse et constituée principalement de roches calcaires, argileuses, schisteuses,... Les gaz de combustion ont un long temps de résidence dans les fours. De plus, le mode de fonctionnement des fours est responsable d'un effet de lessivage des gaz acides par le cru alcalin. Ces propriétés font du procédé cimentier un bon candidat pour la valorisation énergétique des déchets. Les déchets interessants pour les cimenteries sont, entre autres, les huiles usées, les solvants usés et les pneus usés qui ont un pouvoir calorifique équivalent à celui du charbon. Les rejets à l'atmosphère des cimenteries sont principalement des émissions gazeuses. Ainsi, l'impact de la valorisation de pneus usés sur les émissions gazeuses de la cimenterie Saint-Laurent de Joliette a été étudié, à l'aide de l'outil qu'est la modélisation de la dispersion atmosphérique. Le modèle utilisé ISC-ST2, Industrial Source Complex-Short Term, est de type gaussien. L'analyse des concentrations maximales horaires et moyennes sur différentes périodes de temps (1 heure, 8 heures, ..., 1 an) des émissions gazeuses dans l'air ambiant montre que celles-ci sont en deçà des normes émises par le gouvernement québécois et par la Communauté Urbaine de Montréal. L'étude de la distribution géographique des polluants, d'après les concentrations annuelles, dans un rayon de 5 km autour de la cimenterie montre que le fait d'utiliser des pneus comme combustible de substitution n'a qu'un faible impact sur la concentration des contaminants au niveau du sol. L'étude du modèle gaussien de dispersion a permis de mettre au point un nouvel outil: la corrélation existant entre les concentrations latérales et verticales des polluants dans le panache. Cet outil utilisé pour étudier les schémas de dispersion atmosphérique de Turner en milieu rural, et de Briggs en milieux urbain et rural, montre que, en milieu rural, le schéma de dispersion proposé par Briggs présente une dispersion plus importante que celui de Turner pour les classes neutres et instables et moins importantes pour les classes stables. La comparaison des schémas de Briggs (rural et urbain) confirme que la dispersion en milieu urbain est plus importante qu'en milieu rural.

  13. Developpement d'un catalyseur nickel-alumine efficace pour le reformage de diesel a la vapeur d'eau et etude du systeme reactionnel

    NASA Astrophysics Data System (ADS)

    Fauteux-Lefebvre, Clemence

    Le developpement de sources d'energie alternatives fiables et efficaces est aujourd'hui une necessite. L' interet dans le reformage d'hydrocarbures liquides est ainsi croissant puisqu'il s'agit d'une voie pour l'alimentation des piles a combustible. Les piles a combustible ont une efficacite pour la conversion d'energie en electricite plus grande que celle des moteurs a combustion et font ainsi partie de la recherche de solution en efficacite energetique. Ces piles consomment de l'hydrogene comme combustible pour produire de l'electricite, d'ou l'interet pour le reformage. En effet, cette reaction permet de produire de l'hydrogene et du monoxyde de carbone (un autre combustible des piles a combustible a electrolyte solide) a partir d'hydrocarbure liquide, notamment le diesel. Les piles pourraient donc etre integrees avec une unite de reformage leur fournissant directement le combustible necessaire a partir de diesel. Dans ce projet de recherche, un nouveau catalyseur de nickel sous forme de spinelle nickel-alumine (spinelle NiAl2O4 sur support d'alumine et de zircone stabilisee avec yttria) a ete developpe et teste en laboratoire pour du reformage de propane, d'hydrocarbures liquides et de diesel, a la vapeur d'eau. Par ailleurs, une methode d'ajout des reactifs novatrice a ete utilisee afin de diminuer la pyrolyse precedant le reformage, en utilisant une emulsion. Les resultats de reformage d'hydrocarbures purs ont montre des concentrations tres pres de l'equilibre thermodynamique et une activite constante sans desactivation du catalyseur ni formation de carbone, et ce avec des ratios H2O/C de moins de 2.5 et des temperatures d'operation variant entre 630 °C et 750 °C. Lors de tests effectues en utilisant du diesel fossile, a 705°C, avec un debit volumique des reactifs de plus de 50 000 cm3gcat-1h-1 et un ratio H2O/C de moins de 2.5, l'activite a ete maintenue pendant plus de 15 heures, malgre une operation en cycles. L'analyse du catalyseur apres cette utilisation n'a montre aucun carbone significatif sur la surface.- En comparaison, un catalyseur de nickel metallique sur support d'Al2O3 et YSZ a ete utilise dans des conditions similaires. Il y a eu desactivation du catalyseur et obstruction du reacteur par du carbone apres trois heures d'operation. L'analyse de ce catalyseur a permis de verifier qu'il etait recouvert de carbone en filament. L'analyse du systeme reactionnel a montre que la reaction est controlee par la reaction de. surface et non par le transfert de masse. Par ailleurs, les analyses des catalyseurs de spinelle ont demontre qu'il n'y avait pas de modification de sa forme chimique ni de reduction du spinelle en nickel metallique apres l'utilisation. Mots cles : Reformage a la vapeur, diesel, hydrocarbure liquide, catalyseur, spinelle nickel-alumine, equilibre thermodynamique

  14. Modelisation de la dependance de l'espace et du temps dans les etudes d' environnementModelamiento de la dependencia espacial y temporal en estudios ambientales

    NASA Astrophysics Data System (ADS)

    Stein, Alfred; Sterk, Geert

    This paper analyzes the use of stratification in the modeling of dependence for regionalized variables in space and time. Stratification enables optimal use of available information, and it is used when deterministic, small-scale information is combined with large-scale random variation: on the one hand, the problem of having too few data to reliably estimate statistical parameters may be solved by stratification; on the other hand some variation may be so obvious that it serves as a prerequisite for obtaining any form of stationarity. The paper is illustrated with four case-studies. The first study analyzes optimization of an extant groundwater monitoring network within a catchment of the river Rhine. Stratification in space enabled 5 cm precision of predicted levels at critical locations, something that could not be reached without stratification. The second study analyzed variability in space and time of wind erosion in a field. Erosion by four storms was measured with 21 devices. Use of temporal stratification to overcome lack of spatial data resulted, in one instance, in a decrease of 17 percent in mean absolute error. The third study addressed changes in the soil solution influenced by environmental deposition over a period of six years. Stratification was made in space to enable analysis in the time domain and to obtain spatio-temporal maps. The fourth study used a general space-time model to evaluate the development of root-rot in soybean, caused by naturally occurring pathogens. Predictions were made at unvisited times to estimate the probability of occurrence of root rot. We conclude that use of stratification enhances the utility of space-time statistics for the solution of various environmental and agricultural problems.

  15. [Long-term clinical tolerance of antihypertensive treatment during the HOT study. Groupe français de l'etude HOT].

    PubMed

    Mallion, J M; Dahan, R; Boutelant, S; Benkritly, A; Baguet, J P; Noir-Clerc, M

    1997-08-01

    The objective of the HOT study, an international, prospective, randomised study is to determine the optimal level of the blood pressure under treatment, in linked with the lowest cardiovascular mortality and morbidity. The target diastolic blood pressure of 80, 85 and 90 mmHg was determined at the randomisation. In order to reach the target blood pressure, a strategy of treatment was determined: the 1st step was felodipine (a long acting dihydropyridine) and the next steps (if the blood pressure reduction is not enough) propose the addition of different therapeutic classes and/or the increase of each drug doses. The available data after 2 years of the patients follow-up allow us to evaluate the incidence of the reported side effects according to the target blood pressure assigned by randomisation and the number of hypertension drugs used to reach these targets. The percentage of patients with at least one side effect at 12 and 24 months of follow-up are respectively: for the target group DBP < or = 90 mmHg: 9.2% versus 6%; for the target group DBP < or = 85 mmHg: 8% versus 4.4%; for the target group DBP < or = 80 mmHg: 7.9% versus 4.9%. The overall tolerability is not influenced by the target diastolic blood pressure but depends on the number of hypertension drugs used. At 24 months, 2.8% of patients are under monotherapy; 7% under bitherapy and 9.8% under tritherapy. The incidence of the side effects decreases after the 1st year, but slower than between the third months and the first year. There is an influence of the region on the incidence of the side effects, the south European countries describing more side effects than France or the north European countries. This seems to be linked with a perception of the side effects more than with a higher rate. In conclusion, these results confirm the possibility to reach a targeted blood pressure using a predetermined strategy without increasing dramatically the incidence of the side effects.

  16. Etude experimentale et optimisation d'un systeme hybride hydraulique pour camions a ordures et amelioration des performances par raffinement de sa logique de controle

    NASA Astrophysics Data System (ADS)

    Lacroix, Benoit

    The aim of this thesis is to demonstrate experimentally the operation of a hydraulic hybrid system specifically dedicated to the application of refuse trucks in addition to proposing solutions to improve its control strategy. The developed hybrid system recovers the vehicle's kinetic energy during braking. A variable displacement hydraulic motor then uses the energy stored in a hydraulic accumulator to assist the internal combustion engine (ICE) at suitable times. The particular aspect of this system is that assistance to the ICE can occur when it operates at idle and drives the auxiliary hydraulic equipment of the refuse truck. Essentially, the control strategy initially developed maximizes the recovery of braking energy and uses that energy to minimize the solicitation of the ICE at idle. The experimental results obtained with two prototypes tested in real operating conditions show that the hybrid system can recover a significant portion of braking energy. In addition, the results show that it is possible to reduce the load on the ICE during idle with the application of an assisting torque. However, the advantage of assisting the ICE in specific areas of the operating range is slim since the ICE's gross efficiency varies only slightly depending on conditions of operation. This is confirmed by the optimization of the control logic using deterministic dynamic programming. Indeed, by managing the pressure in the accumulator to maximize the amount of energy recovered during braking and by dosing the assistance to the ICE in an ideal fashion, the optimal control only managed to improve fuel savings by 6% in comparison to the original control. Therefore, since the efforts that would be required to emulate the ideal behavior in real time are significant for a relatively small and uncertain gain, the initial control logic is considered near optimal. Finally, this thesis proposes an improved version of the torque assisting hybrid system that could shut down the ICE when the vehicle is stopped while maintaining functional the auxiliary hydraulic equipment. An optimization of the control logic indicates that proper management of the pressure in the accumulator would allow turning off the ICE most of the time at stop and thus, would increase the fuel savings by over 40% compared to the original system. The simulation of a basic control strategy shows that such pressure management may be feasible in real time and that the potential gain in fuel savings is achievable. Keywords: hybrid system, hydraulic, control, refuse truck.

  17. Passage de la Langue Maternelle a la Langue Etrangere: Etude Experimentale (From the Native Language to the Foreign Language: An Experimental Study).

    ERIC Educational Resources Information Center

    Bourguignon, Christiane

    1979-01-01

    Reports on an experiment designed to test French secondary students' intuitive understanding of the nuances among six semantic categories of the structure "'etre' plus past participle," and their ability to translate these nuances into a second language (English or Spanish). (AM)

  18. Etude comparative sur la propagation de l'endommagement apres impact des composites carbone/epoxy renforces par piquage au fil Kevlar et titane-nickel

    NASA Astrophysics Data System (ADS)

    Vachon, Pierre-Luc

    Composite laminates have strong in-plane mechanical properties, but they are generally weaker through their thickness. This specificity makes the laminates prone to delamination, particularly under low-velocity impact loads. Consequently numerous research efforts have been dedicated to developing interlaminar reinforcing methods, such as transverse stitching. The present project proposes the use of the stitching technique combined with a special stitching thread made of superelastic TiNi alloy. This technology is intended to improve the delamination toughness in composite laminates loaded in bending. In the first part of this study a numerical model was developed for analyzing composite structures. The 3-D finite element model was built with the ANSYS commercial software using 20-node solid and 8-node shell elements. The progressive damage modeling technique was used, allowing the prediction of delamination propagation in a laminate submitted to various loading modes. The model was validated for a plate under quasi-static traction load, and it was then used to simulate three-point bending tests. Secondly, carbon/epoxy composite panels were fabricated, with each panel containing unstitched and stitched specimens. Two different materials were used for the stitching thread: superelastic TiNi wires and Kevlar threads as a reference. Some stitched specimens were cut in slices in order to make some observations of the internal stitch using an optical microscope. Standardized low-velocity impact tests and compression after impact tests were carried out on stitched and unstitched specimens (ASTM D7136 and D7137). The Kevlar reinforcements have shown great performance in reducing the delaminated zone after impact, as well as in improving the residual compression strength. The TiNi reinforcements provided encouraging results during the impact tests, though being less effective than the Kevlar threads. During the compression after impact tests, only a slight difference could be measured between the TiNi-stitched and the unstitched specimens. Then the bending performance of the specimens was quantified experimentally by calculating the energy required to create a unit volume of damaged material (Gv, J/mm3). This metric is similar to the Strain Energy Release Rate (SERR) commonly used in studies on delamination. According to the experimental results, the damage resistance in three-point bending was not improved by the Kevlar reinforcements, despite the reduced damaged zone after the impact test. Indeed, when the strain energy in bending is relativized to the induced damaged volume during propagation, it turns out that the TiNi reinforcements are more effective than the Kevlar's for improving the damage resistance. Finally, the numerical study on the behavior of both types of stitched reinforcements allowed identifying subtle differences between those. Indeed, both stitching threads (TiNi and Kevlar) promoted the interlaminar propagation of the delamination during simulation of the bending test, with this behavior being less pronounced for the TiNi-stitched plate. However the Kevlar threads seemed more effective for stopping this propagation in the zones between the stitches. Keywords: composite materials, stitching, numerical model, shape memory alloy, three-point bending, low-velocity impact, ultrasound imaging.

  19. Model Study of a Proposed Engineering Acoustic Research Facility (Etude sur Modele d’un Projet d’Installation de Recherches en Genie Acoustique)

    DTIC Science & Technology

    1976-07-01

    Toronto E.H. Dudgeon, Head/Chef D.C. MacPhail ,Engine Laboratory/ Laboratoire des moteurs Director/Directeur GO O/L/ D~~~~~~r1ISTRIBUT1I...acceptable et une faible sensibilit A la deviation du jet ont W ddfinies, mais ces dispositifs n’ont &6 rgalisds qu’au detriment du rendement

  20. Elaboration d'un simulateur de gravure par plasma de haute densite base sur une approche cellulaire pour l'etude de profils dans divers materiaux

    NASA Astrophysics Data System (ADS)

    Saussac, Jerome

    Sub-micrometer and nanometer-size device manufacturing requires perfect control of fabrication processing, in particular plasma etching. The fabrication of such devices is complex and the requirements in terms of quality and geometry of the etching profiles impose to use the best adapted operating conditions. Simulation of space and time-etching profile evolution that is proposed in this thesis addresses these issues. The simulator yields a better understanding of the fundamental mechanisms that occur during plasma etching of features in various materials. It enables to test the influence of plasma parameters on the profile shape and thus to determine the optimal operating conditions. The development of the simulator is based on the fundamental concepts in plasma etching. From thorough review of the various numerical approaches available to simulate etching profile evolution, we have developed a stable and flexible algorithm that enables to emphasize the importance of some key-parameters for the realization of etching profiles by high-density and low-pressure plasma. The capabilities of this algorithm were tested on the study of Si sputtering in an argon plasma and of ion-assisted chemical etching of SiO2/Si in a chlorine plasma. From comparisons between simulated and experimental profiles, we have shown the importance of some parameters, like the nature of the gas, the plasma pressure, the initial shape of the mask, the mask/material selectivity, the neutral/ion flux ratio, etc. We also linked these parameters to the formation of defects in the profile, for exemple mask facetting, sidewall bowing and microtrenching. Finally, we have shown that redeposition of sputtered atoms compete with electric surface charging to explain V-shape profiles observed on Pt sputtered in argon plasmas. Keywords. plasma, etching, profile, simulation, silicon, platinum, redeposition, microtrenching

  1. Etude de l'influence de defauts sur les proprietes mecaniques de materiaux composites fabriques par le procede de placement de fibres

    NASA Astrophysics Data System (ADS)

    Legay, Pierre

    2011-07-01

    The effect of automated fiber placement defects on composite material mechanical properties needs to be characterized. Impact behavior and laminate compressive properties can be affected by these defects. This study aims at characterizing the effect of AFP defects on impact (ASTM D7136), compression after impact (ASTM D7137) and open hole compression properties (ASTM D6484) of a quasi-isotropic carbon/epoxy laminate (G40-800/5276-1). The defects that we studied were “critical” because they were located in every plies of same orientation and they were stacked. First, we performed open hole compression tests on coupons containing defects. 7 defect configurations were studied with gaps and overlaps placed in the compression direction and perpendicular to the compression direction. The results are compared with an analytical modeling of defects and they reveal that if defects are placed along compression direction they do not cause stress concentrations which lead to specimen failure. If defects are placed in plies which are perpendicular to compression direction, fiber waviness leads to a more important reduction of compressive strength. But electron microscope observations revealed that fiber waviness only affect plies that are adjacent to defects (+/-45°) and do not affect 0° plies which carry most of the load. It explains that compressive strength reduction is low even for 90° defects. Then we performed impact and compression after impact tests. We studied the results of impact tests (impactor contact force and impact absorbed energy) and we also performed ultrasonic measures (C-scan) and electron microscope observations, it allowed us to characterize impact damages. We first studied the effect of impact energy on laminate damage modes. For lower impact energies there is no damage in the material. When the impact energy increases, matrix cracking and délaminations appear, they are followed by the first fiber fractures. The damage spreads in plies which are opposed to the impact point. For higher energies, material properties are highly reduced and the laminate cannot support the load increase, the damage propagates through the laminate thickness. Finally impact and compression after impact tests performed on coupons containing defects reveal that gaps and overlaps have a local effect on damage: defects do not affect coupons global mechanical properties.

  2. European Gene Mapping Project (EUROGEM): breakpoint panels for human chromosomes based on the CEPH reference families. Centre d'Etude du Polymorphisme Humain.

    PubMed

    Cox, S A; Attwood, J; Bryant, S P; Bains, R; Povey, S; Rebello, M; Kapsetaki, M; Moschonas, N K; Grzeschik, K H; Otto, M; Dixon, M; Sudworth, H E; Kooy, R F; Wright, A; Teague, P; Terrenato, L; Vergnaud, G; Monfouilloux, S; Weissenbach, J; Alibert, O; Dib, C; Fauré, S; Bakker, E; Pearson, N M; Spurr, N K

    1996-11-01

    Meiotic breakpoint panels for human chromosomes 2, 3, 4, 5, 6, 7, 8, 9, 10, 13, 14, 15, 17, 18, 20 and X were constructed from genotypes from the CEPH reference families. Each recombinant chromosome included has a breakpoint well-supported with reference to defined quantitative criteria. The panels were constructed at both a low-resolution, useful for a first-pass localization, and high-resolution, for a more precise placement. The availability of such panels will reduce the number of genotyping experiments necessary to order new polymorphisms with respect to existing genetic markers. This paper shows only a representative sample of the breakpoints detected. The complete data are available on the World Wide Web (URL http:/(/)www.icnet.uk/axp/hgr/eurogem++ +/HTML/data.html) or by anonymous ftp (ftp.gene.ucl.ac.uk in/pub/eurogem/maps/breakpoints).

  3. Etude structurale et vibrationnelle d’un nouveau composé complexe de cobalt: [Co(imidazole)4Cl]Cl

    PubMed Central

    Derbel, Amira; Mhiri, Tahar; Graia, Mohsen

    2015-01-01

    In the title complex, chlorido­tetra­kis­(1H-imidazole-κN 3)cobalt(II) chloride, [CoCl(C3H4N2)4]Cl, the CoII cation has a distorted square-pyramidal coordination environment. It is coordinated by four N atoms of four imidazole (Im) groups in the basal plane, and by a Cl atom in the apical position. It is isostructural with [Cu(Im)4Cl]Cl [Morzyk-Ociepa et al. (2012 ▸). J. Mol. Struct. 1028, 49–56] and [Cu(Im)4Br]Br [Hossaini Sadr et al. (2004 ▸). Acta Cryst. E60, m1324–m1326]. In the crystal, the [CoCl(C3H4N2)4]+ cations and Cl− anions are linked via N—H⋯Cl hydrogen bonds, forming layers parallel to (010). These layers are linked via C—H⋯Cl hydrogen bonds and C—H⋯π and π–π [inter-centroid distance = 3.794 (2) Å] inter­actions, forming a three-dimensional framework. The IR spectrum shows vibrational bands typical for imidazol groups. The monoclinic unit cell of the title compound emulates an ortho­rhom­bic cell as its β angle is close to 90°. The crystal is twinned, with the refined ratio of twin components being 0.569 (1):0.431 (1). PMID:26594402

  4. Etude microdosimetrique de l'influence des materiaux sur l'efficacite biologique d'une source d'iode-125

    NASA Astrophysics Data System (ADS)

    Taschereau, Richard

    Cette these concerne les implants permanents pour la prostate. Les isotopes employes, le 103Pd et l'125I, semblent produire les memes resultats cliniques: le premier a cause d'une radiation plus efficace et le second a cause de sa demi-vie plus longue. La recherche utilise le cadre theorique de la microdosimetrie et des simulations Monte Carlo. Elle propose d'employer le spectre d'ejection dans le calcul de l'efficacite; ce changement fait passer l'efficacite relative du 103Pd de 10% a 5%. Elle montre ensuite qu'il est possible d'ameliorer l'efficacite de la radiation de 125I par l'exploitation des rayons X caracteristiques de la capsule. Une source amelioree faite de molybdene et d'yttrium est donnee en exemple. Elle procure une radiation de 5--7% plus efficace, ce qui surclasse les deux sources existantes. Les applications ne se limitent pas au traitement de la prostate; le traitement du melanome oculaire et la curietherapie endovasculaire pourraient en beneficier.

  5. Etude par Imagerie à faible Niveau dans le proche Infrarouge d'une Emission de la haute Atmosphère

    NASA Astrophysics Data System (ADS)

    Pautet, Pierre-Dominique

    2000-12-01

    Le travail effectué a eu pour but la mise en place d'un protocole d'observation et de traitement des images, ainsi que les outils appropriés, visant à l'étude d'une émission de la haute atmosphère terrestre dans le proche infrarouge. Il existe actuellement des télescopes comme le VLT (Very Large Telescope), installé au Chili, qui permettent d'observer des astres et des galaxies distants de plusieurs millions de parsecs. A cause de l'expansion de l'Univers, des objets situés aussi loin s'éloignent très rapidement de nous. Le spectre de leur émission qui nous parvient alors est décalé vers le rouge ou l'infrarouge, du fait de l'effet Doppler. Il faut donc observer ces objets dans des longueurs d'onde appropriées. Malheureusement, l'atmosphère terrestre qui nous sépare d'eux est aussi le siège de nombreuses émissions qui peuvent venir perturber les mesures. De toutes ces émissions, la principale est due au radical OH dont les raies de rotation-vibration couvrent tout le spectre entre 0,7 et 2,5 microns. Cette émission a lieu au niveau d'une couche assez fine de la haute atmosphère appelée mésopause et située à environ 85 kilomètres d'altitude. Le travail effectué a eu pour but de mettre en évidence les principales caractéristiques de cette émission qui n'est pas uniforme et constante dans le temps. Un programme d'observations dans le proche infrarouge a été élaboré. Plusieurs algorithmes de traitement d'image ont été développés. Un programme d'inversion de perspective a été mis au point pour une utilisation en temps réel sur le terrain. Les caractéristiques des images peuvent être ensuite analysées. La première partie du mémoire comporte une description des différentes émissions lumineuses que l'on peut observer la nuit lorsque l'on regarde la voûte céleste. Ces émissions peuvent avoir deux origines: astronomique ou atmosphérique. Le problème de l'absorption atmosphérique et plus précisément les conditions requises pour de bonnes observations dans le domaine du proche infrarouge ont aussi été étudiées. Ensuite, la construction d'une station mobile de prise de vues est détaillée. Celle-ci doit permettre d'observer l'émission et d'obtenir des résultats exploitables par la suite. Trois méthodes d'observation ont été décrites: visuelle, photographique et à l'aide d'un détecteur CCD. La troisième, qui a été retenue, a été vue plus en détail. Le matériel utilisé, de la caméra à la plate-forme de prise de vues en passant par les objectifs et les filtres optiques, est ensuite décrit. Lorsque le matériel a été choisi, un protocole d'observation a été défini et mis au point. Le choix du site d'observation a été crucial. Plusieurs lieux géographiques ont été retenus et sont présentés dans le mémoire. Le déroulement d'une séance de prise de vue a été décrit afin de faciliter un futur programme d'observation. Deux séquences types d'observations ont été plus particulièrement détaillées: -la réalisation de panoramas permettant une étude des structures que fait apparaître l'émission, -la réalisation de séquences vidéos afin d'étudier la dynamique du phénomène. Dans une quatrième partie, je décris les méthodes de traitement des images qui ont été développées. Tout d'abord, des prétraitements sont appliqués aux images pour corriger les défauts (champ plat, offset,?). Ensuite, une méthode de restitution géographique permet d'obtenir une image plus exploitable de la couche émissive ; elle n'est alors plus observée à partir d'une station au sol, mais en employant une caméra virtuelle située à la verticale du site d'observation. Différents problèmes liés à cette méthode ont aussi été traités: réfraction atmosphérique proche de l'horizon, passage d'une surface atmosphérique à la surface du pixel correspondant, et effet de Van Rhijn. Plusieurs traitements ont été appliqués aux images pour faciliter leur exploitation: filtrage pour supprimer les objets parasites tels que les étoiles, amélioration du contraste, mise en évidence des structures par plusieurs méthodes. Les résultats de l'étude de ces structures sont ensuite exposés. La dernière partie du travail porte sur l'étude dynamique de l'émission. Tout d'abord, nous avons vu la variation globale de celle-ci au cours de la nuit, puis la dynamique des structures elles-mêmes ainsi que l'influence de cette émission sur les observations astronomiques. Des observations en collaboration avec l'équipe du lidar-Rayleigh de l'Observatoire de Haute-Provence ont permis d'établir une corrélation entre les variations de la densité des composés atmosphériques et les variations de l'intensité de l'émission étudiée. D'autres observations simultanées ont été effectuées avec une équipe située au Pic du Midi afin de réaliser une triangulation visant à déterminer avec précision l'altitude de la couche émissive. Les directions à suivre afin de continuer cette étude ont finalement été données. Les objectifs d'un tel programme consistant à obtenir une meilleure connaissance de la structure de la haute atmosphère terrestre et une amélioration des corrections des observations astronomiques en temps réel.

  6. Etude du comportement et de la modélisation viscoplastique du zircaloy 4recristallisé sous chargements monotones et cycliques uni et multiaxes

    NASA Astrophysics Data System (ADS)

    Delobelle, P.; Robinet, P.

    1994-08-01

    The results of experiment performed on a recrystallized zircaloy 4 alloy in the intermediate temperature domain 20 leqslant T leqslant 400 ^{circ}C are presented. To characterize the anisotropy, especially at 350 ^{circ}C, the tests were made under both monotonic and cyclic uni- and bidirectional loadings, i.e. tension-compression, tension-torsion and tension-internal pressure tests. The different anisotropy coefficients and especially R^p = \\varepsilon^p_{θθ} /\\varepsilon^ p _ {{^-_-}{^-_-} } seem to be temperature independent. An important feature of the behavior of this alloy in the neighbourhood of 300 ^{circ}C is attributed to the dislocations-point defects interactions (dynamic strain aging), phenomena often observed in the solid solutions. For the 2D cyclic non proportional loadings it is shown that a weak supplementary hardening appears, which is a function of the degree of the phase lag. We propose to particularize and to apply a unified viscoplastic model with internal variables to the considered alloy, as the model as already been developed and identified elsewhere for other isotropic materials. From a general point of view the introduction of the anisotropy in the model is made by four tensors of rank 4 ; [ M] is assigned to the flow directions, [ N] to the linear parts of the kinematical hardening variables and [ Q] , [ R] respectively to the dynamic and static recoveries of these tensorial variables. This phenomenological formulation leads to a correct representation of the set of the experimental results presented at 350 ^{circ}C, which provides an a posteriori confirmation of the formalism used. On étudie, entre 20 et 400 ^{circ}C, à l'aide d'essais sous chargements multiaxiaux monotones et cycliques (traction, torsion et pression interne) les propriétés viscoplastiques anisotropes de tube de zircaloy 4 recristallisé. A la température de 350 ^{circ}C, l'anisotropie a été quantifiée de façon détaillée. Les quelques résultats obtenus à la température ambiante ainsi que l'indépendance du rapport R^p = \\varepsilon^p_{θθ}/\\varepsilon^ p_{{^-_-}{^-_-} } avec la température laissent supposer que l'ensemble des coefficients d'anisotropie ne dépendent pas de la température. Par contre, la fluidité de cet alliage présente un minimum très marqué au voisinage de 300 ^{circ}C. Ce comportement est imputable au vieillissement dynamique fréquemment observé dans les solutions solides d'insertion. Lors d'un chargement cyclique hors phase (traction-torsion déphasée à 90^{circ}) ce matériau présente un léger durcissement supplémentaire. On propose l'extension au cas du zircaloy 4 de la formulation d'un modèle viscoplastique unifié développé et identifié par ailleurs sur d'autres matériaux initialement isotropes. D'une manière générale, l'introduction de l'anisotropie dans ce modèle s'effectue par l'intermédiaire de quatre tenseurs d'ordre 4 affectant les directions d'écoulement [ M] , les parties linéaires des écrouissages cinématiques [ N] , ainsi que les restaurations dynamiques [ Q] et statiques [ R] de ces mêmes variables d'écrouissage. L'identification de ce modèle est discutée et réalisée à 350 ^{circ}C. On montre l'adéquation du formalisme à appréhender l'ensemble des caractéristiques mécaniques de cet alliage.

  7. Etude des aspects cliniques, échographiques et nutritionnels du syndrome des ovaires micropolykystiques (SOMPK) à Mbuji-Mayi, RD du Congo

    PubMed Central

    Kalenda, Louis Mbuyamba Ntobo; Mikenji, Justin Biayi; Nkoy, Albert Mwembo-Tambwe; Kayamba, Prosper Kalenga Muenze

    2014-01-01

    Introduction Le Syndrome des Ovaires Micropolykystiques (SOMPK) est polymorphe. L'objectif de cette étude était de déterminer la prévalence et rechercher les facteurs nutritionnels éventuellement associés. Méthodes Chez 300 patientes atteintes de SOMPK faisant l'objet de cette étude, les données anamnestiques, cliniques et échographiques, et les habitudes alimentaires ont été analysées. Les statistiques usuelles et les mesures d'association ont été utilisées pour analyser les résultats. Résultats La prévalence de SOMPK était de 23,6%. L’âge moyen des patientes avec SOMPK était 24 ± 7 ans et chez celles sans SOMPK 36 ± 7 ans (P < 0,05). Le risque de développer le SOMPK en présence d'un niveau de vie élevé était de 2,03 (RR = 2,03; IC à 95%: 1,73-2,38; P = 0,00). Le risque de développer le SOMPK en exerçant une activité légère est de 2,15 (RR = 2,15; IC à 95%: 1,87-2,87; P= 0,00). La proportion des patientes avec SOMPK ayant accumulé plus de 2400 kcal était de 59% vs 36% (P < 0,05) et le risque de développer le SOMPK lorsque l’énergie accumulée était supérieure à 2400 kcal était de 1,57 (RR = 1,57; IC à 95%: 1,33-1,85; P= 0,00). Conclusion Dans notre milieu la prévalence de SOMPK était de 23,6%. Les facteurs associés au SOMPK étaient l’âge, l’énergie accumulée de plus de 2400 Kcal, le niveau socio-économique élevé et l'activité physique légère. Des études analytiques plus poussées sont nécessaires, pour évaluer la force du risque que représentent ces différents facteurs étudiés. PMID:25870722

  8. Etude experimentale de la photoexcitation des colorants de type anthracene, azobenzene et thioindigo dans des matrices de cristaux liquides nematiques et smectiques

    NASA Astrophysics Data System (ADS)

    Saad, Bendaoud

    Nous avons étudié le comportement de différents colorants (tétracène et azobenzènes AZD3, DR1 et D2) dans des matrices de cristaux liquides (E7 et 5CB). Les résultats obtenus ont montré que la réorientation optique des molécules de cristaux liquides se produit à des intensités extrêmement faibles (~1 μW/cm 2). Nous avons attribué cet effet à l'interaction entre les molécules des colorants photoexcitées et celles des cristaux liquides hôtes. Ces interactions se produisent lorsque les molécules dichroïques exçitées transitent entre des états triplets intermédiaires tout en conduisant à la génération d'un nouveau moment optique géant, responsable de la réorientation des molécules. Le changement de la forme de la molécule du colorant, dû à l'isomérisation Trans-Cis , est à l'origine de la création de ce moment. Ce qui distingue notre réorientation moléculaire de celle obtenue sur d'autres systèmes hôtes-dopants est que les molécules sont repoussées du champ électrique de la lumière. Par ailleurs, cette réorientation est accompagnée d'une diffusion anisotrope des molécules excitées. Nous avons aussi étudié le cristal liquide PhBz rendu ferroélectrique en le dopant par des molécules thioindigos. En exploitant l'augmentation de la polarisation spontanée due à la photoisomérisation du colorant, nous avons pu réaliser un hologramme dynamique contrôlable par un champ optique assisté par une tension statique.

  9. Etude de la preparation de poudres et de depots a partir de suspension par plasma inductif: Le cas de l'hydroxyapatite phosphocalcique

    NASA Astrophysics Data System (ADS)

    Bouyer, Etienne

    The work presented in this thesis has been directed to the study and the development of a new thermal spray process now known as the "SPS" (Suspension Plasma Spraying), in which the raw material to be treated is initially a liquid suspension. The SPS process is employed either for the preparation of thick coating or to the production of spherical and dense powders. The principle of SPS is the axial injection of a suspension into the plasma core by gas atomization. The atomization droplets are successively dried, melted and accelerated in the plasma plume. Finally, melt droplets strike a substrate and solidify to build the coating (deposition route) or are solidified in-flight and are then collected from within the reactor (powder route). The SPS process is best achieved with the use of r.f. thermal plasma technology and has been applied to the complex shape forming of ceramic materials: e.g. hydroxyapatite (HA), Ca10(PO4)6(OH) 2. HA, which is a bioceramic used in various biomedical applications such as bone substitute. The original chemical synthesis of the HA is a key step for the control of physical and chemical properties of the HA suspension which in turn are fundamental to the success of the entire SPS process. HA decomposes at elevated temperatures. With proper control of the plasma spraying parameters (i.e. the nature of the plasma gas and its composition, plasma power level, pressure, etc), the in-flight plasma decomposition can be minimized. Moreover it is possible to control the coating texture, its crystallinity and adhesion strength while maintaining high deposition rates (>150 mum/min). The morphology of powders prepared by the SPS technique and the size of resultant powders depends strongly on the atomization parameters of the spray suspension in the plasma. Water promotes the stabilization of HA during the plasma treatment and therefore helps to limit its in-flight decomposition. The SPS process is a potentially powerful technology providing in-flight reaction routes for new materials synthesis and shaping, both as powders and as finished coatings. A further advantage of the SPS process concerns its economics through the used of a reduced number of process steps required in comparison to conventional plasma spray process.

  10. Canadian Mathematics Education Study Group = Groupe Canadien d'etude en didactique des matematiques. Proceedings of the Annual Meeting (St. Catharines, Ontario, Canada, May 27-31, 1989).

    ERIC Educational Resources Information Center

    Pereira-Mendoza, Lionel, Ed.; Quigley, Martyn, Ed.

    These conference proceedings include two invited lectures, four working group reports, five topic group reports, a list of participants, and a list of previous proceedings. The invited lectures were: "Teaching Mathematical Proof: Relevance and Complexity of a Social Approach" (Nicolas Balacheff) and "Geometry Is Alive and…

  11. Cubitus varus: l'ostéotomie de soustraction externe a-t-elle toujours sa place? Etude rétrospective à propos de 25 cas

    PubMed Central

    Chagou, Aniss; Bassir, Réda Allah; Rhanim, Abdelkarim; Lahlou, Abdou; Berrada, Mohammed Saleh; Yaacoubi, Moradh

    2016-01-01

    Le cubitus varus est cal vicieuxle plus souvent secondaire à des fractures supracondyliennes déplacées de l'extrémité inférieure de l'humérus chez l'enfant. Différentes techniques chirurgicales ont été proposées avec un taux de réussite différents mais aussi un taux de complications rapportées différents. Nous évaluons à travers une étude rétrospective de 25 cas colligés au centre hospitalier universitaire de Rabat, les résultats de la technique de soustraction externe que nous utilisons dans notre formation pour prendre en charge cette déformation. PMID:27516828

  12. L'ilot du reservoir: etude de voisinage en milieu urbain (The Reservoir Block: A Study of a Neighborhood in an Urban Setting).

    ERIC Educational Resources Information Center

    Rey, Jean-Noel

    1983-01-01

    An analysis of a small neighborhood of Paris looks at its layout and spatial constraints, habitats, symbols, sense of territory, and rhythms and styles of the inhabitants and their roles in the group. The description, including photos, is intended for use in the French language classroom. (MSE)

  13. Meteorological conditions during the formation of ice on aircraft

    NASA Technical Reports Server (NTRS)

    Samuels, L T

    1932-01-01

    These are the results of a number of records recently secured from autographic meteorological instruments mounted on airplanes at times when ice formed. Ice is found to collect on an airplane only when the airplane is in some form of visible moisture, such as cloud, fog, mist, rain. etc., and the air temperature is within certain critical limits. Described here are the characteristics of clear ice and rime ice and the specific types of hazards they present to airplanes and lighter than air vehicles. The weather records are classified according to the two general types of formation (clear ice and rime) together with the respective temperatures, relative humidities, clouds, and elevations above ground at which formations occurred. This classification includes 108 cases where rime formed, 43 cases in which clear ice formed, and 4 cases when both rime and clear ice formed during the same flight. It is evident from the above figures that there was a preponderance of rime by the ratio of 2.5 to 1, while in only a few cases both types of ice formation occurred during the same flight.

  14. Comparison of observed and simulated spatial patterns of ice microphysical processes in tropical oceanic mesoscale convective systems

    NASA Astrophysics Data System (ADS)

    Barnes, Hannah C.; Houze, Robert A.

    2016-07-01

    To equitably compare the spatial pattern of ice microphysical processes produced by three microphysical parameterizations with each other, observations, and theory, simulations of tropical oceanic mesoscale convective systems (MCSs) in the Weather Research and Forecasting (WRF) model were forced to develop the same mesoscale circulations as observations by assimilating radial velocity data from a Doppler radar. The same general layering of microphysical processes was found in observations and simulations with deposition anywhere above the 0°C level, aggregation at and above the 0°C level, melting at and below the 0°C level, and riming near the 0°C level. Thus, this study is consistent with the layered ice microphysical pattern portrayed in previous conceptual models and indicated by dual-polarization radar data. Spatial variability of riming in the simulations suggests that riming in the midlevel inflow is related to convective-scale vertical velocity perturbations. Finally, this study sheds light on limitations of current generally available bulk microphysical parameterizations. In each parameterization, the layers in which aggregation and riming took place were generally too thick and the frequency of riming was generally too high compared to the observations and theory. Additionally, none of the parameterizations produced similar details in every microphysical spatial pattern. Discrepancies in the patterns of microphysical processes between parameterizations likely factor into creating substantial differences in model reflectivity patterns. It is concluded that improved parameterizations of ice-phase microphysics will be essential to obtain reliable, consistent model simulations of tropical oceanic MCSs.

  15. Comparison of observed and simulated spatial patterns of ice microphysical processes in tropical oceanic mesoscale convective systems: Ice Microphysics in Midlevel Inflow

    SciTech Connect

    Barnes, Hannah C.; Houze, Robert A.

    2016-07-25

    To equitably compare the spatial pattern of ice microphysical processes produced by three microphysical parameterizations with each other, observations, and theory, simulations of tropical oceanic mesoscale convective systems (MCSs) in the Weather Research and Forecasting (WRF) model were forced to develop the same mesoscale circulations as observations by assimilating radial velocity data from a Doppler radar. The same general layering of microphysical processes was found in observations and simulations with deposition anywhere above the 0°C level, aggregation at and above the 0°C level, melting at and below the 0°C level, and riming near the 0°C level. Thus, this study is consistent with the layered ice microphysical pattern portrayed in previous conceptual models and indicated by dual-polarization radar data. Spatial variability of riming in the simulations suggests that riming in the midlevel inflow is related to convective-scale vertical velocity perturbations. Finally, this study sheds light on limitations of current generally available bulk microphysical parameterizations. In each parameterization, the layers in which aggregation and riming took place were generally too thick and the frequency of riming was generally too high compared to the observations and theory. Additionally, none of the parameterizations produced similar details in every microphysical spatial pattern. Discrepancies in the patterns of microphysical processes between parameterizations likely factor into creating substantial differences in model reflectivity patterns. It is concluded that improved parameterizations of ice-phase microphysics will be essential to obtain reliable, consistent model simulations of tropical oceanic MCSs.

  16. L'evaluation des programmes d'etudes au Quebec. Etude de cas: Les programmes des techniques d'education en services de garde au Cegep de Saint-Jerome (The Evaluation of Programs of Study in Quebec. Case Study: Child Care Education Programs in CEGEP Saint Jerome).

    ERIC Educational Resources Information Center

    Quebec Commission on the Evaluation of Collegiate Teaching (Quebec).

    Providing a case study of instructional organization and evaluation processes in Quebec's "Colleges d'enseignement general et professionnel" (CEGEPs), this report describes the provincial Commission on the Evaluation of Collegiate Teaching and a 1994 evaluation of "Techniques d'education en services de garde" (TESG), or child…

  17. Additional Study of Water Droplet Median Volume Diameter (MVD) Effects on Ice Shapes

    NASA Technical Reports Server (NTRS)

    Tsao, Jen-Ching; Anderson, David N.

    2005-01-01

    This paper reports the result of an experimental study in the NASA Glenn Icing Research Tunnel (IRT) to evaluate how well the MVD-independent effect identified previously might apply to SLD conditions in rime icing situations. Models were NACA 0012 wing sections with chords of 53.3 and 91.4 cm. Tests were conducted with a nominal airspeed of 77 m/s (150 kt) and a number of MVD's ranging from 15 to 100 m with LWC of 0.5 to 1 g/cu m. In the present study, ice shapes recorded from past studies and recent results at SLD and Appendix-C conditions are reviewed to show that droplet diameter is not important to rime ice shape for MVD of 30 microns or larger, but for less than 30 m drop sizes a rime ice shape transition from convex to wedge to spearhead type ice shape is observed.

  18. Measurements of local convective heat transfer coefficients on ice accretion shapes

    NASA Technical Reports Server (NTRS)

    Arimilli, R. V.; Keshock, E. G.; Smith, M. E.

    1984-01-01

    The thin-skin heat rate technique was used to determine local convective heat transfer coefficients for four representative ice accretion shapes. The shapes represented three stages of glaze ice formation and one rime ice formation; the ice models had varying degrees of surface roughness. In general, convective heat transfer was higher in regions where the model's surfaces were convex and lower in regions where the surfaces were concave. The effect of roughness was different for the glaze and rime ice shapes. On the glaze ice shapes, roughness increased the maximum Nu by 80 percent, but the other Nu values were virtually unchanged. On the rime ice shape, the Nu numbers near the stagnation point were unchanged. The maximum Nu value increased by 45 percent, and the Nu number downstream of the peak increased by approximately 150 percent.

  19. Wind tunnel evaluation of air-foil performance using simulated ice shapes

    NASA Technical Reports Server (NTRS)

    Bragg, M. B.; Zaguli, R. J.; Gregorek, G. M.

    1982-01-01

    A two-phase wind tunnel test was conducted in the 6 by 9 foot Icing Research Tunnel (IRT) at NASA Lewis Research Center to evaluate the effect of ice on the performance of a full scale general aviation wing. In the first IRT tests, rime and glaze shapes were carefully documented as functions of angle of attack and free stream conditions. Next, simulated ice shapes were constructed for two rime and two glaze shapes and used in the second IRT tunnel entry. The ice shapes and the clean airfoil were tapped to obtain surface pressures and a probe used to measure the wake characteristics. These data were recorded and processed, on-line, with a minicomputer/digital data acquisition system. The effect of both rime and glaze ice on the pressure distribution, Cl, Cd, and Cm are presented.

  20. 5 W à 255 nm et 15 kHz obtenus par doublage defréquence d'un laser CuHBr dans du BBO

    NASA Astrophysics Data System (ADS)

    Huot, N.; Jonin, C.; Le Harzic, R.; Audouard, E.; Laporte, P.

    2003-06-01

    5.1 W de rayonnement ultra-violet ont été obtenus à 15 kHz par doublage de fréquence de la raie à 510.6 nm d'un laser CuHBr dans deux cristaux de BBO. La qualité de faisceau du rayonnement UV est exprimée par le paramètre M^2 : M_X^2 = 30± 2 et M_Y^2= 24 ± 2. Les deux faisceaux UV issus des deux cristaux de BBO, combinés au point focal d'une lentille, permettent le micro-usinage UV à haute cadence.

  1. Une Exception Francaise: Les Grandes Ecoles (A French Exception: The Great Schools).

    ERIC Educational Resources Information Center

    Kimmel, Alain

    1996-01-01

    Examines the role of exceptional schools in France that have produced famous personages such as Charles de Gaulle and Jean-Paul Sartre. The schools reviewed include L'Ecole Nationale d'Administration, L'Ecole Polytechnique, L'Ecole Normale Superieure, L'Ecole des Hautes Etudes Commerciales, Saint-Cyr, and L'Institut d'Etudes Politiques de Paris.…

  2. Multi-Scale Autoregressive Processes

    DTIC Science & Technology

    1989-06-01

    rationnelles et leurs langages," Mas- son 1984, Collection "Etudes et Recherches en Informatique". [12] J.L. DUNAU, "Etude d’une classe de marches...June 1989 LIDS-P-1880 Multi-Scale Autoregressive Processes Michele Basseville’ Albert Benveniste’ Institut de Recherche en Informatique et Systemes...Centre National de la Recherche Scientifique (CNRS) and A.B. is also with Institut National de Recherche en Informatique et en Automatique (INRIA). The

  3. The Support of Air Operations Under Extreme Hot and Cold Weather Conditions (Les Operatons Aeriennes en Environnement Extreme Chaud/Froid)

    DTIC Science & Technology

    1993-10-01

    provide pilotage infoaon to the to 16 personnel between the Antarctic two British Antarctic Survey research and the Falkland Wlands, considerably...diminui~o. L’utllisation d’un ontraino un effet do sorre. Enfin lo systbme do climatisation indivduoello ost rayonnement do Idlectroniquo do bord ...sodt uno pormottre tour utilisation A bord dos avions do arni~ioration do la climatisation dos a6ronefs, combat. soft rutilisation cruno

  4. Measurement of Optical Limiting Threshold in Various Matenals

    DTIC Science & Technology

    2001-10-01

    high-performance carbon suspension named DREV CBS-100. Thresholds as low as 24 mJ/cm2 (nanosecond regime) and 100 mJ/cm2 (microsecond regime) have...Les recherches sur les materiaux susceptibles de proteger les yeux et les capteurs electro...optiques contre le rayonnement laser par limitation optique ont montre que de fines particules de carbone en suspension dans un liquide presentent des

  5. Influence of consonantal context on the pronunciation of vowels: a comparison of human readers and computational models.

    PubMed

    Treiman, Rebecca; Kessler, Brett; Bick, Suzanne

    2003-05-01

    In two experiments, we found that college students' pronunciations of vowels in nonwords are influenced both by preceding and following consonants. The predominance of rimes in previous studies of reading does not appear to arise because readers are unable to pick up associations that cross the onset-rime boundary, but rather because English has relatively few such associations. Comparisons between people's vowel pronunciations and those produced by various computational models of reading showed that no model provided a good account of human performance on nonwords for which the vowel shows contextual conditioning. Possible directions for improved models are suggested.

  6. ESA is hot on the trail of Geminga

    NASA Astrophysics Data System (ADS)

    close to the neutron star. Geminga’s breathless rotation rate - once every quarter of a second - creates an extraordinary environment in which electrons and positrons, their antimatter counterparts, can be accelerated to extraordinarily high energies. At such energies, they become powerful high-energy gamma-ray producers. Astronomers had assumed that all the electrons would be converted into gamma rays. However, the discovery of the tails proves that some do find escape routes from the maelstrom. “It is astonishing that such energetic electrons succeed in escaping to create these tails,” says Caraveo, “The tail electrons have an energy very near to the maximum energy achievable in the environment of Geminga.” The tails themselves are the bright edges of the three-dimensional shockwave sculpted by Geminga. Such shockwaves are a bit like the wake of a ship travelling across the ocean. Using a computer model, the team has estimated that Geminga is travelling almost directly across our line of sight. Studies of Geminga could not be more important. The majority of known gamma-ray sources in the Universe have yet to be identified with known classes of celestial objects. Some astronomers believe that a sizeable fraction of them may be Geminga-like radio-quiet neutron stars. Certainly, the family of radio-quiet neutron stars, discovered through their X-ray emission, is continuously growing. Currently, about a dozen objects are known but only Geminga has a pair of tails! Note for editors During the search to track down this elusive celestial object, a co-author on the paper, Giovanni Bignami, named Geminga almost 30 years ago. He was Principal Investigator of XMM-Newton's EPIC camera from 1987 to1997 and is now Director of the Centre d'Etude Spatiale des Rayonnements (CESR). Geminga was first glimpsed as a mysterious source of gamma rays, coming from somewhere in the constellation Gemini by NASA's SAS-2 spacecraft in 1973. While searching to pin down its exact location

  7. Some Microphysical Processes Affecting Aircraft Icing.

    DTIC Science & Technology

    1985-05-08

    1978) Messung , Darstellung, and Auswertung meteorologischer Vereisungs parameter, Berich te Fuiden Geophysicalischern Beratungdienst der Bundeswehr...de-icing of the Hot Rod. The aircraft experienced light to moderate rime icing until its slight descent at 09:03. It then continued to experience ...1978) Messung . Darstellung, and Auswertung meteorologischer Vereisungs parameter, Benich te Fuiden Geophysicalischern Beratungydienst der Bundeswehr

  8. Development of Phonological Awareness in Bilingual Chinese Children

    ERIC Educational Resources Information Center

    Chen, Xi; Ku, Yu-Min; Koyama, Emiko; Anderson, Richard C.; Li, Wenling

    2008-01-01

    This study investigated the phonological awareness of 219 first, second, and fourth grade Cantonese-speaking children from the south of China, who received immersion Mandarin instruction beginning in the first grade. Children received onset, rime and tone awareness tasks in Cantonese and Mandarin. Children performed better on the Cantonese onset…

  9. A Comparative Study Using CFD to Predict Iced Airfoil Aerodynamics

    NASA Technical Reports Server (NTRS)

    Chi, x.; Li, Y.; Chen, H.; Addy, H. E.; Choo, Y. K.; Shih, T. I-P.

    2005-01-01

    WIND, Fluent, and PowerFLOW were used to predict the lift, drag, and moment coefficients of a business-jet airfoil with a rime ice (rough and jagged, but no protruding horns) and with a glaze ice (rough and jagged end has two or more protruding horns) for angles of attack from zero to and after stall. The performance of the following turbulence models were examined by comparing predictions with available experimental data. Spalart-Allmaras (S-A), RNG k-epsilon, shear-stress transport, v(sup 2)-f, and a differential Reynolds stress model with and without non-equilibrium wall functions. For steady RANS simulations, WIND and FLUENT were found to give nearly identical results if the grid about the iced airfoil, the turbulence model, and the order of accuracy of the numerical schemes used are the same. The use of wall functions was found to be acceptable for the rime ice configuration and the flow conditions examined. For rime ice, the S-A model was found to predict accurately until near the stall angle. For glaze ice, the CFD predictions were much less satisfactory for all turbulence models and codes investigated because of the large separated region produced by the horns. For unsteady RANS, WIND and FLUENT did not provide better results. PowerFLOW, based on the Lattice Boltzmann method, gave excellent results for the lift coefficient at and near stall for the rime ice, where the flow is inherently unsteady.

  10. Feed up, Back, Forward

    ERIC Educational Resources Information Center

    Fisher, Douglas; Frey, Nancy

    2009-01-01

    Like the ancient sailor in "The Rime of the Ancient Mariner" who lamented, "water, water everywhere nor any drop to drink," many teachers feel awash in a sea of assessment data that they don't know how to use. Part of the solution, Fisher and Frey claim, is for educators to understand the three components of any effective…

  11. Exploring Assessment Demands and Task Supports in Early Childhood Phonological Awareness Assessments

    ERIC Educational Resources Information Center

    Cassano, Christina M.; Steiner, Lilly

    2016-01-01

    Phonological awareness is assessed in various ways in both research studies and early childhood classrooms. The measures used to assess phonological awareness are related closely, although they differ in the linguistic unit used (e.g., word, syllable, onset-rime, or phoneme), the position of the linguistic unit (e.g., initial, medial, final), the…

  12. Polyhedral Oligomeric Silsesquioxane-Functionalized Perfluorocyclobutyl Aryl Ether Polymers: An Overview of the Synthesis and Properties of Polyhedral Oligomeric Silsesquioxanes (POSS) Functionalized with Perfluorocyclobutyl (PFCB) Aryl Ether Polymer Blends and Copolymers (Preprint)

    DTIC Science & Technology

    2007-10-17

    Contact Analyzer System or a Rime-Hart 100-00 115 Goniometry. Liquid drops were either automatically or manually dispensed with 8 10 L drop sizes...C.; Barthlott, W. Ann. Bot. 1997, 79, 677. 2. Barthlott, W.; Nenhuis, C. Planta 1997, 202, 1. 3. Sun, T.; Feng, L.; Gao, X.; Jian, L. Acc

  13. A Question of Evidence, or a Leap of Faith?

    ERIC Educational Resources Information Center

    Howard, Jennifer

    2008-01-01

    Did he or didn't he? The question is vexing Coleridge scholars. Did the author of "Christabel," "Kubla Khan," and "The Rime of the Ancient Mariner" compose a blank-verse translation of Goethe's "Faust" that was published anonymously in London in 1821? Two prominent Romanticists, Frederick Burwick and James C. McKusick, both Americans, believe they…

  14. Neural Correlates of Mapping from Phonology to Orthography in Children Performing an Auditory Spelling Task

    ERIC Educational Resources Information Center

    Booth, James R.; Cho, Soojin; Burman, Douglas D.; Bitan, Tali

    2007-01-01

    Age-related differences (9- to 15-year-olds) in the neural correlates of mapping from phonology to orthography were examined with functional magnetic resonance imaging (fMRI). Participants were asked to determine if two spoken words had the same spelling for the rime (corresponding letters after the first consonant or consonant cluster). Some of…

  15. Monitoring Variability and Change in Children's Spelling Strategies

    ERIC Educational Resources Information Center

    Farrington-Flint, Lee; Stash, Amanda; Stiller, James

    2008-01-01

    This study examined the role of variability and change in children's strategy performance within the context of spelling. The spelling ability of 34 eight- to nine-year-olds was examined using an experimental spelling task comprising 45 items, which varied with regard to rime unit frequency. The spelling task incorporated a series of consistent,…

  16. Phonological Awareness Is Child's Play!

    ERIC Educational Resources Information Center

    Yopp, Hallie Kay; Yopp, Helen

    2009-01-01

    Noticing and being able to manipulate the sounds of spoken language-phonological awareness-is highly related to later success in reading and spelling. The authors define and explain the levels of phonological awareness-syllable awareness, onset-rime awareness, phoneme awareness. They give teachers step-by-step instructions for implementing a…

  17. The Developmental Turnpoint of Orthographic Consistency Effects in Speech Recognition

    ERIC Educational Resources Information Center

    Ventura, Paulo; Kolinsky, Regine; Pattamadilok, Chotiga; Morais, Jose

    2008-01-01

    The influence of orthography on children's online auditory word recognition was studied from the end of Grade 4 to the end of Grade 9 by examining the orthographic consistency effect in auditory lexical decision. Fourth-graders showed evidence of a widespread influence of orthography in their spoken word recognition system; words with rimes that…

  18. Repeated Reading Intervention Effects in Kindergartners with Partial Letter Knowledge

    ERIC Educational Resources Information Center

    van Gorp, Karly; Segers, Eliane; Verhoeven, Ludo

    2014-01-01

    The direct, transfer and retention effects of a repeated reading intervention study of single CVC (consonant in the onset and a vowel and consonant in the rime) words in kindergartners with partial letter knowledge were examined. A total of 26 second-year kindergartners participated in this study. Participants were divided over two feedback…

  19. A Developmental Model of Reading Acquisition Based upon Early Scaffolding Errors and Subsequent Vowel Inferences

    ERIC Educational Resources Information Center

    Savage, Robert; Stuart, Morag

    2006-01-01

    This paper investigates the processes that predict reading acquisition. Associations between (a) scaffolding errors (e.g., "torn" misread as "town" or "tarn"), other reading errors, and later reading and (b) vowel and rime inferences and later reading were explored. To assess both of these issues, 50 6-year-old children were shown a number of CVC…

  20. Subsyllabic Unit Preference in Learning to Read Pinyin Syllables

    ERIC Educational Resources Information Center

    Wang, Min; Gao, Wei

    2011-01-01

    We designed two experiments to investigate subsyllabic unit preference in reading Pinyin in Chinese kindergarteners. Pinyin is an alphabetic transcription used in Mainland China to assist children in learning to read Chinese characters. In Pinyin instruction, teachers rely heavily on onset-rime division. Spoken Chinese, however, encourages…

  1. The Army and Multinational Peace Operations: Problems and Solutions

    DTIC Science & Technology

    1993-11-29

    type of enforcement operations described in Chapter 7 of the U.N. Charter. According to Richard Connaughton , these may not require developing an organic...Peacekeeping Roles," New York rimes, December 12, 1993, p. 22; Brian Hall, "Blue Helmets,* New York Times Magazine, January 2, 1994, pp. 19-29; and Richard

  2. In the Beginning Was the Rhyme? A Reflection on Hulme, Hatcher, Nation, Brown, Adams, and Stuart (2002).

    ERIC Educational Resources Information Center

    Goswami, Usha

    2002-01-01

    Describes phonological sensitivity at different grain sizes as a good predictor of reading acquisition in all languages. Presents information on development of phonological sensitivity for syllables, onsets, and rimes. Illustrates that phoneme-level skills develop fastest in children acquiring orthographically consistent languages with simple…

  3. USSR Report, Military Affairs

    DTIC Science & Technology

    2007-11-02

    salt. It is like an antique fresco in the drizzling rain: under the rime are mottled nimbuses and images, outlines of trees and temples. But these...frigates. The heraldry of foreign ’machines’ are a help to the signaller. It is a 20th century fresco . The ship is in neutral waters. A city lies

  4. Cues for Lexical Tone Perception in Children: Acoustic Correlates and Phonetic Context Effects

    ERIC Educational Resources Information Center

    Tong, Xiuli; McBride, Catherine; Burnham, Denis

    2014-01-01

    Purpose: The authors investigated the effects of acoustic cues (i.e., pitch height, pitch contour, and pitch onset and offset) and phonetic context cues (i.e., syllable onsets and rimes) on lexical tone perception in Cantonese-speaking children. Method: Eight minimum pairs of tonal contrasts were presented in either an identical phonetic context…

  5. The Stress Patterns of Nonsense English Words of Cantonese-Speaking ESL Learners.

    ERIC Educational Resources Information Center

    Wong, Cathy Sin Ping

    1991-01-01

    This paper explores the issue of the acquisition of English word stress by ESL learners whose mother tongue is Cantonese. Based on the theoretical framework of metrical phonology, this study examines the following parameters related to English word stress: branching versus non-branching rime structures, dominance in the metrical foot and the word…

  6. Teaching Avalanche Safety Courses: Instructional Techniques and Field Exercises.

    ERIC Educational Resources Information Center

    Watters, Ron

    This paper discusses course structure, teaching techniques, and field exercises for enhancing winter travelers' avalanche knowledge and skills. In two class sessions, the course typically consists of a historical perspective; a section on snow physics (clouds, types of snow crystals, effects of riming, identification of precipitated snow crystals,…

  7. Proceedings: Eighteenth Annual Conference on Research in Medical Education, Washington, D.C., November 6-7, 1979.

    ERIC Educational Resources Information Center

    Jones, Deborah L., Comp.

    The Research in Medical Education (RIME) Program Planning Committee's selections for program materials for the eighteenth annual conference on Research in Medical Education are contained in this volume. The agenda consisted of poster sessions, presentation of papers, and presentation of symposia. Poster sessions examined such topics as student…

  8. Assimilation of Long-Range Lightning Data over the Pacific

    DTIC Science & Technology

    2010-09-30

    charge separation, with ice particles, graupel, and supercooled water coexisting in the mixed phase region, was present throughout the mature phase of...freezing of raindrops and grew by riming with supercooled cloud droplets. This process resulted in a substantial amount of frozen precipitation

  9. Assimilation of Long-Range Lightning Data over the Pacific

    DTIC Science & Technology

    2011-09-30

    particles, graupel, and supercooled water coexisting in the mixed phase region, was present throughout the mature phase of the simulated...particles formed through the freezing of raindrops and grew by riming with supercooled cloud droplets. This process resulted in a substantial amount of

  10. Report of the AMC Software Task Force

    DTIC Science & Technology

    1989-02-28

    Inadequate rime/Resources for SW Development Poor understamding of true software support cost No Identificd-ion/ Justificacion of Resources in CRMPs...effect of introducing stringent design goals k for reliability provide only a minimal productivity improvement 16 Problemas ’when considered

  11. Basic Auditory Processing and Developmental Dyslexia in Chinese

    ERIC Educational Resources Information Center

    Wang, Hsiao-Lan Sharon; Huss, Martina; Hamalainen, Jarmo A.; Goswami, Usha

    2012-01-01

    The present study explores the relationship between basic auditory processing of sound rise time, frequency, duration and intensity, phonological skills (onset-rime and tone awareness, sound blending, RAN, and phonological memory) and reading disability in Chinese. A series of psychometric, literacy, phonological, auditory, and character…

  12. The Development of Phonological Awareness with Specific Language-Impaired and Typical Children

    ERIC Educational Resources Information Center

    Thatcher, Karen L.

    2010-01-01

    This study investigated kindergarten, preschool, and first-grade children who were typical or specific language impaired (SLI) to determine whether there were developmental differences in their phonological awareness abilities (i.e., syllable, onset/rime, phonemes). Results revealed a significant difference between children who were typical and…

  13. Fast and Slow Namers: Benefits of Segmentation and Whole Word Training.

    ERIC Educational Resources Information Center

    Levy, Betty Ann; Bourassa, Derrick C.; Horn, Christopher

    1999-01-01

    Trained fast- and slow-namer groups of poor-reading second graders to read words using different training regimes. Found that slow namers were particularly disadvantaged compared to fast namers when trained with word-level units. Children showed poorer retention following onset/rime training compared to other types. They showed the best…

  14. Chemotherapy of Rodent Malaria.

    DTIC Science & Technology

    1982-10-01

    COMPOUND NAME LI’T 117q ~tr h OR NUMBER ........................... PARASITE (SUB)SPECIES .. . . . . . . . Tween 80 /11 0 FORMULATION...rime thami ne P. be r ghe iOR NUMBER ........................... PARASITE (SUB)SPECIES ................. Tween 80 /H 90 FORMULATION...ne f). be. r !,he i OR NUMBER ........................... PARASITE (SUB)SPLCIES ............. Tween 80 /1 2() FORMULATION ................... ROUTE OF

  15. Telemetre Laser a Onde Entretenue a 10.6 micrometers avec Postdetection non Lineaire: Etude d’un Systeme a un Laser (A 10.6 micrometer Amplitude Modulated Telemeter Laser with Nonlinear Postdetection: Study of a Single Laser System),

    DTIC Science & Technology

    1981-04-01

    compatibles avec les syst~mes FLIR 10 Uim et dont la transmission 9 travers une atmosphere poussi6reuse ou l~g~rement brurneuse (r6f. 5) semble bonne. Ce projet ...la detection homodyne (un seul laser comme 6metteur et OL) en modes homodyne (~f WO et h6t6rodyne (f IF #O) avec un detecteur HgCdTe suivi d’un syst~me

  16. Conception et validation d'un modele d'analyse et de suivi pour une politique energetique durable et acceptable de l'energie eolienne: Une etude comparative France-Quebec

    NASA Astrophysics Data System (ADS)

    Feurtey, Evariste

    In this research, we built a conceptual model of a sustainable and acceptable wind power policy that we tried to validate through the case study of France and Quebec in the wind energy sector. Our qualitative and comparative approach helps us to illustrate the interaction of institutional variables studied, including the national context of emergence, the balance of power between pressure groups, the supranational and exogenous influences, level of political commitment, policy and regulatory instruments, social acceptance and energy policy mechanisms. The research confirms that the neo-corporatism is present in France as in Quebec. With the unfavorable energy context (low cost of electricity tariff, lack of electricity demand, and an already low zero carbon electric mix), it is an important factor explaining : 1) the 20 years delay accumulated by France and Quebec in the development of wind projects or industrial sector; 2) the 10% limited penetration scale given to wind energy. We also demonstrate that the political commitment to develop wind energy fluctuates with the government majority, the energy context or the influence of pressure groups. This manifests itself in a lack of continuity of policies and tariff instruments used. In both national case studies, the results also show that balanced policies and regulations ensure sustainable development of wind energy only if they allow a sufficient market size. The search results also illustrates that the conceptual division made between acceptance of wind sector, acceptance of ownership, local acceptance is very instructive. Social controversies, though multifactorial, are connected to both a critique of the development model too industrial and private, territorial dilemmas (closed environment), energy context (electric surplus in Quebec), or related to strategic planning system and centralized decision. An important issue for a more acceptable wind policy in the future will come to a greater plurality of ownership, variety of wind projects scale, diversity of financial support mechanisms. This transformation to a more territorial policy that require renewables also calls for decentralization and ecological modernization of institutions. Sustainable and acceptable energy policy requires obtaining a stabilized consensus on the long-term energy mix, which should be done by a comprehensive energy and public debate upstream the development of energy policy. Keywords: energy policy, social acceptance, wind energy, environmental assessment, components, interactions.

  17. Etude du transfert de quelques oligo-éléments dans les chaînes trophiques néritiques et estuariennes: Accumulation biologique chez les poissons omnivores et super-carnivores

    NASA Astrophysics Data System (ADS)

    Metayer, C.; Amiard, J.-C.; Amiard-Triquet, C.; Marchand, J.

    1980-06-01

    Five species of fishes (Dicentrarchus labrax, Gobius microps, Stizostedion lucioperca, Gadus luscus, Merlangius merlangus) and their major prey organisms were collected monthly from two stations in the Loire estuary (France). The levels of several trace elements (Cd, Pb, Cu, Zn) in their tissues were determined by means of atomic absorption spectrophotometry. The concentrations of Cd, Pb and Cu were shown to decrease in the highest trophic levels: the relatively highest metal levels were determined in annelids, followed by crustaceans, the lowest levels being encountered in fishes. However, a preferential uptake of Cu was observed in crustaceans. There is no biomagnification for these three metals, the concentrations in preys being generally lower than in predators. For Zn, the highest concentrations were measured in worms and copepods but preys such as shrimps and mysids exhibit values of the same order of magnitude compared to predator fishes.

  18. Idiopathic chronic eosinophilic pneumonia. A clinical and follow-up study of 62 cases. The Groupe d'Etudes et de Recherche sur les Maladies "Orphelines" Pulmonaires (GERM"O"P).

    PubMed

    Marchand, E; Reynaud-Gaubert, M; Lauque, D; Durieu, J; Tonnel, A B; Cordier, J F

    1998-09-01

    Idiopathic chronic eosinophilic pneumonia (CEP) is a rare disorder of unknown cause with nonspecific respiratory and systemic symptoms but rather characteristic peripheral alveolar infiltrates on imaging, developing mainly in women and in atopic subjects. The disorder is highly responsive to oral corticosteroid therapy, but relapses are frequent on reducing or stopping treatment. The long-term course of the disease and data regarding outcome, particularly the need for prolonged oral corticosteroid therapy and the development of severe asthma, are somewhat contradictory. A multicentric retrospective study was conducted in an attempt to describe better the initial features and, above all, the later course of CEP in a large homogeneous series of 62 stringently selected patients of whom 46 were followed for more than 1 year. The prevalence of smokers was low (6.5%) and about half of our patients (51.6%) had a previous, and often prolonged, history of asthma. The clinical and roentgenographic features were in keeping with previous studies, but we found that computed tomography could disclose ground glass opacities not detected by X-ray, and that migratory infiltrates before treatment were more frequent (25.5%) than reported previously. The bronchoalveolar lavage cellular count always showed a striking eosinophilic pattern, thus allowing distinction between CEP and cryptogenic organizing pneumonia, both syndromes sharing many common clinical and imaging features. About two-thirds of the patients (68%) showed a ventilatory defect in pulmonary function tests, with about one-half of these presenting with an obstructive pattern, sometimes without previous asthma. Along with the submucosal eosinophilic infiltration noted in 2 patients without ventilatory defect, this is strong evidence to confirm that CEP is not only an alveolointerstitial but also an airway disease. The dramatic response to oral corticosteroid therapy was observed in all treated patients. Although only 1 patient initially treated for less than 6 months did not relapse, longer oral corticosteroid therapy in no way provided protection from further relapses. We thus propose to try to wean oral corticosteroid therapy after 6 months in patients without severe asthma, because recurrences remain responsive to oral steroids. However, prolonged oral corticosteroid therapy was necessary in the majority of patients, with 68.9% of those followed for more than 1 year still on oral corticosteroid therapy at the last follow-up, either because of relapse or because of severe asthma.

  19. French Language Arts: Programme d'etudes par annee scolaire. Francais langue seconde--immersion. Huitieme annee (French Language Arts: Yearly Curriculum. French as a Second Language--Immersion. Eighth Year).

    ERIC Educational Resources Information Center

    Alberta Dept. of Education, Edmonton. Language Services Branch.

    The report, entirely in French, describes Alberta's curriculum for eighth-year French immersion, as revised in 1998. An introductory section offers background information on the curriculum revision, links between the core curriculum and French immersion, underlying principles of second language instruction, the revised curriculum's objectives and…

  20. French Language Arts: Programme d'etudes par annee scolaire. Francais langue seconde--immersion. Septieme annee (French Language Arts: Yearly Curriculum. French as a Second Language--Immersion. Seventh Year).

    ERIC Educational Resources Information Center

    Alberta Dept. of Education, Edmonton. Language Services Branch.

    The report, entirely in French, describes Alberta's curriculum for seventh-year French immersion, as revised in 1998. An introductory section offers background information on the curriculum revision, links between the core curriculum and French immersion, underlying principles of second language instruction, the revised curriculum's objectives and…

  1. French Language Arts: Programme d'etudes par annee scolaire. Francais langue seconde--immersion. Neuvieme annee (French Language Arts: Yearly Curriculum. French as a Second Language--Immersion. Ninth Year).

    ERIC Educational Resources Information Center

    Alberta Dept. of Education, Edmonton. Language Services Branch.

    The report, entirely in French, describes Alberta's curriculum for ninth-year French immersion, as revised in 1998. An introductory section offers background information on the curriculum revision, links between the core curriculum and French immersion, underlying principles of second language instruction, the revised curriculum's objectives and…

  2. French Language Arts: Programme d'etudes du secondaire deuxieme cycle (10-12). Francais langue seconde--immersion (French Language Arts: High School Curriculum [10-12]. French as a Second Language--Immersion).

    ERIC Educational Resources Information Center

    Alberta Dept. of Education, Edmonton. Language Services Branch.

    The report, entirely in French, describes Alberta's curriculum for high school French immersion, as revised in 1998. An introductory section offers background information on the curriculum revision, links between the core curriculum and French immersion, underlying principles of second language instruction, the revised curriculum's objectives and…

  3. Etude comparative des complications liées à l'utilisation du cathéter veineux périphérique avec et sans système clos à bouchon hépariné

    PubMed Central

    Liu, Ying Chun; Seydou, Togo; Sadio, Yéna; Liang, Tu Zheng; Ge, jin

    2015-01-01

    Introduction L'utilisation correcte du système clos à bouchon hépariné sur les cathéters périphériques pendant les perfusions est une pratique courante dans les pays développés et aussi dans plusieurs pays en développement selon un consensus international établi. Nous comparons les résultats de la formation de thrombus et de l'infection liées au cathéter veineux périphérique chez les patients ayant bénéficié de perfusion avec système clos à bouchon hépariné (groupe expérimentale) et ceux qui ont été perfusé sans bouchon hépariné (groupe témoin). Méthodes Nous avons colligé 100 patients hospitalisés pendant la période de Juillet 2014 à Décembre 2014 dans le service d'hospitalisation de chirurgie thoracique de l'hôpital du Mali qui ont été repartis en 2 groupes de 50 patients chacun pour une analyse comparative. L'observation du thrombus dans la lumière du cathéter est effectuée puis enregistré et tous les cathéters ont été repris pour réalisation de culture bactérienne au laboratoire dans les 2 groupes. Résultats Dans le groupe témoin, il existe un thrombus dans la lumière du cathéter dans 36 cas (72%) et l'examen de culture bactérienne était positif dans 90%. Tandis que dans le groupe expérimental on retrouve 3 cas (6%) de thrombose du cathéter et on note une absence de germe dans l'examen bactériologique. Conclusion L'utilisation correcte du système clos à bouchon hépariné lors des perfusions peut réduire et prévenir de façon significative les complications liées au cathéter notamment l'occlusion par thrombus, leur migration et la survenue de l'infection. PMID:26600900

  4. Le contexte du materiel pedagogique dans l'anglais de specialite. Etude sur les themes tires de l'environnement (The Context of Instructional Materials for ESP. A Study of Themes Drawn from the Environment).

    ERIC Educational Resources Information Center

    Williams, Ray

    1981-01-01

    Challenges the idea that ESP courses should be based strictly on instructional materials taken from the relevant professional context. Accordingly recommends a multidisciplinary themes approach as illustrated in the detailed description of the methods and materials used in a course offered by the University of Aston (Birmingham). Societe Nouvelle…

  5. L'E.A.P. ou l'anglais enseigne dans les etudes superieures. Un guide pour le debutant (E.A.P. or English for Academic Purposes: A Guide for the Beginner).

    ERIC Educational Resources Information Center

    Roe, Peter J.

    1981-01-01

    Addresses those readers who are not familiar with EAP, offering an introductory discussion of its objectives and methods, in two parts. Devotes the first part to the needs that justify an EAP approach, and the second to its methodology, with particular attention to interdisciplinary, task-oriented instruction. Societe Nouvelle Didier Erudition, 40…

  6. Les Interferences Semantiques Dans Les Oeuvres D'ahmadou Kourouma et De Mongo Beti: Essai D'etude Comparative [Semantic Interference in the Works of Ahmadou Kourouma and Mongo Beti: Test Comparative Study

    ERIC Educational Resources Information Center

    Tadoum, Jean Paul

    2012-01-01

    This dissertation focuses on the works of two well-known African Francophone novelists, Ahmadou Kourouma from the Ivory Coast and Mongo Beti from Cameroon. The objective of this study is to look at the influences of African oral traditions and analyze the literary transposition of semantic structures from African languages and cultures into the…

  7. Proceedings of the 2007 Annual Meeting of the Canadian Mathematics Education Study Group = Actes de la Rencontre Annuelle 2007 du Groupe Canadien d'Etude en Didactique des Mathematiques (31st, Fredricton, New Brunswick, Canada, Jun 8-12, 2007)

    ERIC Educational Resources Information Center

    Liljedahl, Peter, Ed.

    2008-01-01

    This submission contains the Proceedings of the 2007 Annual Meeting of the Canadian Mathematics Education Study Group (CMESG), held at the University of New Brunswick in Fredricton, New Brunswick. The CMESG is a group of mathematicians and mathematics educators who meet annually to discuss mathematics education issues at all levels of learning.…

  8. Etude comparative des conditions environnementales potentiellement limitantes dans l'etablissement d'une espece aquatique envahissante Clona intestinalis (Linnaeus, 1767) dans deux systemes de bassins versants a l'ile-du Prince-Edouard, Canada

    NASA Astrophysics Data System (ADS)

    Mclaughlin, Janelle

    Aquatic invasive species are a growing global problem. Since the late 1990s, the province of Prince Edward Island (PEI), located on the east coast of Canada, has seen the introduction and the establishment of several species of tunicate. Shortly after their introduction into new aquatic systems such as the Brudenell and Montague rivers, tunicate population exploded to extremely high levels which have had significant impacts on native species populations, the fisheries and aquaculture industries and on the economy of local communities. Brudenell and Montague rivers are located southeast of the province. Comparatively, the aquatic system of Orwell Bay, which is also located in this area, is an exception to the successful establishment of tunicates, despite several successive unintentional introductions. The objective of this research is to identify and understand the main key factors that could potentially limit the establishment of a tunicate species in PEI. This study is based on a comparative approach between the two aquatic systems previously mentioned. The results of this research shows that the Orwell Bay system is characterized by a slightly higher percentage of terrestrial areas with potential soil loss, a shorter water renewal time, a shallower aquatic area, a higher turbidity level, a slightly lower salinity and a slightly higher temperature than the Brudenell and Montague rivers system. One of the environmental variables that showed a significant difference between the two systems in the analysis is turbidity. This study also examines the relationship between different turbidity levels, in terms of suspended inorganic matter, and its potential role in the establishment of the invasive tunicate C. intestinalis. Two laboratory experiments were conducted to evaluate the effect of suspended inorganic matter on primary stages of this species of tunicate. The results show a significant negative effect at higher suspended inorganic matter levels on fertilization rate, larval establishment and survival of juvenile tunicates. All these elements can potentially be key factors on limiting the establishment of a population of C. intestinalis in the Orwell Bay aquatic system. Keywords: Invasive species, watershed, biogeography, tunicate, Ciona intestinalis, universal soil loss equation, hydrodynamic modeling, correspondence analysis, turbidity, environmental tolerance.

  9. Etude théorique de l'interaction de van der Waals entre une sonde métallique et une surface diélectrique : application à la microscopie par mesure de forces atomiques

    NASA Astrophysics Data System (ADS)

    Maghezzi, S.; Girard, C.; van Labeke, D.

    1991-02-01

    The van der Waals interaction force between a metallic tip and a non planar dielectric is derived from a non local formalism. A general formulation is given for a spherical tip of nanometric size and for surfaces of arbitrary shape (monocrystal adsorbed on planar surfaces). The dispersion part of the attractive force is obtained from a non local theory expressed in terms of generalized electric susceptibilities of the two partners. Implications for atomic force microscopy in attractive mode are also discussed. La force d'interaction de van der Waals entre une pointe métallique et une surface diélectrique est calculée à partir d'une théorie non-locale. Plus précisément, on considère comme point de départ que l'interaction sonde-surface est due au couplage entre les fluctuations des densités de charges des solides en présence. De plus, dans cette approche la force de van der Waals est calculée dans le cadre de la théorie de la réponse linéaire en utilisant pour chacun des milieux la fonction réponse non-locale correspondante. En particulier la sonde, de nature métallique, est caractérisée par un jeu de susceptibilités du champ décrites par un formalisme auto-cohérent. On effectue enfin une étude numérique de la force sur des surfaces présentant des corrugations de dimensions nanométriques.

  10. Etude de la génération de bulles dans les hydrocarbures liquides générées par les impulsio.ns de Trichel

    NASA Astrophysics Data System (ADS)

    Kattan, R.; Bonifaci, N.; Denat, A.

    1991-07-01

    The electrical conduction of purified non polar liquids with point-plane electrode geometry was studied as a function of various parameters. For negative polarity of the point a pulse regime have been observed which bears a great similarity with the Trichel pulses. Below the critical pressure of the liquids, bubble formation was correlated with current pulse. In this paper we present a study of the generation and dynamics of the bubble as function of various parameters: injected energy, liquid pressure, liquid properties. The transition to a streamer phenomenon is also investigated. Une étude de la conduction électrique des liquides non polaires très purs, dans une géométrie pointe-plan, a mis en évidence l'apparition d'un régime très régulier d'impulsions de courant en polarité négative de la pointe. Ce régime s'explique par un mécanisme d'avalanches électroniques en phase liquide dans la zone de champ intense qui induit la formation d'une bulle unique. L'énergie injectée est uniquement fonction du rayon de courbure de la pointe. On présente une étude de la génération et de la dynamique de cette bulle en fonction de la nature du liquide, de la pression hydrostatique et de l'énergie injectée. On montre que la dynamique de la bulle est contrôlée par l'inertie du liquide, que sa taille maximale est proportionnelle à l'énergie injectée pour une pression donnée et que cette énergie sert essentiellement à vaporiser le liquide. Dans les conditions où la durée de vie de la bulle et donc sa taille sont élevées, l'impulsion initiale de courant est suivie par des décharges électriques dans la bulle et il y a début de propagation d'un canal gazeux vers le plan (streamer !).

  11. La Lecon d'intonation de Simone de Beauvoir, etude d'intonation declarative comparee (The Lesson on Intonation of Simone de Beauvoir: A Comparative Study of Declarative Intonation).

    ERIC Educational Resources Information Center

    Delattre, Pierre

    1961-01-01

    Spectrographic analysis of two lectures given without notes by Simone de Beauvoir and Margaret Mead allow detailed specification of three forms of intonation characteristic of declarative sentences in English and French. Discussion of the objectives, of analysis procedures, and of results of the study which elaborate on intonational differences…

  12. A weekly regimen with dose escalation of doxorubicin for patients with advanced Hodgkin's lymphoma: results of a phase II study of the Groupe d'Etudes des Lymphomes de l'Adulte (GELA).

    PubMed

    Fermé, Christophe; Brice, Pauline; Michallet, Anne-Sophie; Lederlin, Pierre; Diviné, Marine; Casasnovas, Olivier; Devidas, Alain; Anglaret, Bruno; Cazals-Hatem, Dominique; Mounier, Nicolas

    2007-04-01

    This multicenter phase II study assessed the feasibility and efficacy of a weekly chemotherapy regimen with a moderately escalated dose of doxorubicin administered over 16 weeks, followed by radiation therapy (RT) to bulky sites. From July 1996 to February 1998, 44 untreated patients with stage IIIB-IV Hodgkin's lymphoma (HL), and 0 - 2 risk factors described by the Memorial Sloan-Kettering Cancer Center, were treated. Chemotherapy was a combination of increased-dose doxorubicin with conventional doses of cyclophosphamide, vinblastine, prednisone, vindesine, bleomycin, and etoposide. Patients received four cycles of the weekly regimen for 16 weeks. Forty-one patients received the planned four cycles of chemotherapy, and RT was delivered to 36 patients. The incidence of WHO grade 3 - 4 neutropenia was 90%. A total of 39 patients achieved a complete remission (88.6%). The median follow-up was 95 months. The 7-years freedom from treatment failure and overall survival estimates were 57% (95% confidence interval (CI), 41% - 70%), and 93% (95% CI, 80 - 98%), respectively. The relapse rate was related to the short duration of chemotherapy, and the failure to prevent relapses with consolidation RT. In this study population the 16-week regimen and RT to bulky sites were not sufficient for disease control.

  13. Primary mediastinal large B-cell lymphoma. A clinicopathologic study of 141 cases compared with 916 nonmediastinal large B-cell lymphomas, a GELA ("Groupe d'Etude des Lymphomes de l'Adulte") study.

    PubMed

    Cazals-Hatem, D; Lepage, E; Brice, P; Ferrant, A; d'Agay, M F; Baumelou, E; Brière, J; Blanc, M; Gaulard, P; Biron, P; Schlaifer, D; Diebold, J; Audouin, J

    1996-07-01

    Among non-Hodgkin's lymphomas, primary mediastinal large B-cell lymphoma (PMLCL) has been considered a separate entity that has specific clinical and histological aspects and a poor prognosis. In this study, we reexamined the clinicopathologic features and the response to current treatment of 141 PMLCL and compare them with 916 nonmediastinal large B-cell lymphomas (NMLCL) recorded in the same period and treated with similar combined chemotherapy. The clinical features of PMLCL at diagnosis were largely homogeneous and distinct from NMLCL, with a predilection for young women (59% with a mean age of 37 years versus 42% with a mean age of 54 years), bulky tumor (77% versus 7%, p < 10(4)), high serum lactic dehydrogenase (LDH) level 76% versus 51%, p < 10(4)), and frequent intrathoracic extension to adjacent organs such as pleura, pericardium, and lung. By contrast, extrathoracic or hematologic dissemination was uncommon (2% of bone marrow involvement versus 17%). All patients had diffuse large B-cell nonimmunoblastic, nonanaplastic lymphomas. Histological analysis of the 141 PMLCL evaluated two common patterns: the presence of large cells with clear cytoplasm (found in 38% of cases) and the presence of fibrosis (marked in 25% of cases). The presence of clear cells or intense fibrosis did not constitute prognostic indicators. Immunologic and molecular analysis assessed the profile of bcl-2 expression and the presence of Epstein-Barr virus (EBV) in PMLCL: 30% expressed a high level of bcl-2 protein; EBER RNAs were detected by in situ hybridization in only two of the 41 cases tested. Monotypic light chain restriction could be demonstrated in seven of the 41 PMLCL tested on fixed-section. Treated with polychemotherapy regimens without radiotherapy, 79% of PMLCL patients achieved a complete remission compared with 68% in the NMLCL patient group (p = 0.01). Overall, 3-year survival rates were estimated at 66 and 61%, respectively (p = 0.05), and disease-free survival rates were not significantly different (61 versus 64%). Stratified analysis on the International Prognostic Index (based on age, tumor stage, serum LDH level, and performance status) showed no difference in the overall and disease-free survivals between the two lymphoma groups. In conclusion, PMLCL can be combined with other diffuse large B-cell lymphomas on morphologic grounds; it is not associated with EBV. It responds favorably to treatment and should be managed like other high-grade lymphomas of equivalent histology. However, the uncommon clinical presentation makes it a distinct entity.

  14. Quality of life-adjusted survival analysis of high-dose therapy with autologous bone marrow transplantation versus sequential chemotherapy for patients with aggressive lymphoma in first complete remission. Groupe d'Etude les Lymphomes de l'Adulte (GELA).

    PubMed

    Mounier, N; Haioun, C; Cole, B F; Gisselbrecht, C; Sebban, C; Morel, P; Marit, G; Bouabdallah, R; Ravoet, C; Salles, G; Reyes, F; Lepage, E

    2000-06-15

    Evaluating high-dose therapy (HDT) with autologous stem cell transplantation (ASCT) in term of both duration and quality of life (QOL) presents major interests for patients with non-Hodgkin lymphoma. The quality-adjusted time without symptom and toxicity (Q-TWiST) methodology was applied to the LNH87-2 trial comparing HDT with ASCT versus sequential chemotherapy in 541 patients in first complete remission (CR). Overall survival (OS) and disease-free survival (DFS) curves were used to estimate duration of 4 health states: acute short-term toxicity (Tox1), secondary toxicity (Tox2), time without symptom and toxicity (TWiST), and relapse (Rel). Areas under survival curves (AUC) were retrospectively weighted according to QOL coefficients. HDT increased, but not significantly, TWiST (+2. 4 months in AUC, P =.17) and decreased Rel (-3 months, P <.01). Survival estimates did not differ between the 2 treatments (AUC 47.7 months for OS, 39.7 months for DFS). High-risk patients treated by HDT versus chemotherapy had a significant benefit in DFS (AUC 28.8 versus 24.9 months, P <.01) but not in OS (AUC 37.3 versus 36 months, P =.27). Sensitivity analysis, performed by varying QOL coefficients, demonstrated significant quality-adjusted survival gain in high-risk patients treated by HDT. In low-risk patients, a diagram provided an aid to clinical decision-making. This analysis supports the use of HDT in these patients with adverse prognostic factors in the first CR, even after adjusting for QOL using the Q-TWiST method. (Blood. 2000;95:3687-3692)

  15. Long-term results and competing risk analysis of the H89 trial in patients with advanced-stage Hodgkin lymphoma: a study by the Groupe d'Etude des Lymphomes de l'Adulte (GELA).

    PubMed

    Fermé, Christophe; Mounier, Nicolas; Casasnovas, Olivier; Brice, Pauline; Divine, Marine; Sonet, Anne; Bouafia, Fahdela; Bastard-Stamatoullas, Aspasia; Bordessoule, Dominique; Voillat, Laurent; Reman, Oumedaly; Blanc, Michel; Gisselbrecht, Christian

    2006-06-15

    From 1989 to 1996, 533 eligible patients with stage IIIB/IV Hodgkin lymphoma (HL) were randomly assigned to receive 6 cycles of hybrid MOPP/ABV (mechlorethamine, vincristine, procarbazine, prednisone/Adriamycin [doxorubicin], bleomycin, vinblastine; n = 266) or ABVPP (doxorubicin, bleomycin, vinblastine, procarbazine, prednisone; n = 267). Patients in complete remission (CR) or partial response of at least 75% after 6 cycles received 2 cycles of consolidation chemotherapy (CT) (n = 208) or subtotal nodal irradiation (RT) (n = 210). A better survival probability was observed after ABVPP alone: the 10-year overall survival (OS) estimates were 90% for ABVPP x 8, 78% for MOPP/ABV x 8, 82% for MOPP/ABV with RT, and 77% for ABVPP x 6 with RT (P = .03); and the 10-year disease-free survival (DFS) estimates were 70%, 76%, 79%, and 76%, respectively (P = .09). The 10-year DFS estimates for patients treated with consolidation CT or RT were 73% and 78% (P = .07), and OS estimates were 84% and 79%, respectively (P = .29). These results showed that RT was not superior to consolidation CT after a doxorubicin-induced CR in patients with advanced HL. An analysis of competing risks identified age more than 45 years as a significant risk factor for death, relapse, and second cancers. Prospective evaluation of late adverse events may improve the management of patients with HL.

  16. Etude par spectrométrie Raman de l'interaction entre un substrat de graphite et un mélange MCl 4H 2 ( M = Si, Ti)

    NASA Astrophysics Data System (ADS)

    Vincent, H.; Ponthenier, J. L.; Vincent, C.; Bouix, J.

    1989-06-01

    Raman spectroscopy has been used in order to optimize the reactive CVD conditions for silicium carbide or titanium carbide deposits on carbon fibers. With this technique 50-nm-thick carbide coatings could be characterized at the surface of the individual filament constituting the carbon fibers. In bulk carbon substrates evidence of degraphitization near the carbon/carbide interface was observed.

  17. Proceedings of the Annual Conference of the Canadian Association for the Study of Adult Education/L'Association Canadienne pour L'Etude de L'Education des Adultes (17th, Ontario, Canada, May 29-31, 1998).

    ERIC Educational Resources Information Center

    Taylor, Maurice, Ed.

    These proceedings on the theme, Adult Education Research: Shaping the Future, contain 52 papers. The papers are: "Virtual Adult Education" (W. Archer and D. Conrad); "Reversal Theory Approach to Adult Learning and Education" (M. Atleo); "Objectiver L'Action" (A. Balleux et al.); "Cultural Constructions of…

  18. Proceedings of the 2002 Annual Meeting of the Canadian Mathematics Education Study Group = Actes de la Rencontre Annuelle 2002 du Groupe Canadien d'Etude en Didactique des Mathematiques (26th, Kingston, Ontario, Canada, May 24-28, 2002)

    ERIC Educational Resources Information Center

    Simmt, Elaine, Ed.; Davis, Brent, Ed.

    2003-01-01

    This submission contains the Proceedings of the 2002 Annual Meeting of the Canadian Mathematics Education Study Group (CMESG), held at Queen's University in Kingston, Ontario. The CMESG is a group of mathematicians and mathematics educators who meet annually to discuss mathematics education issues at all levels of learning. The aims of the Study…

  19. Etude theorique et experimentale de la correlation entre la resistance aux chocs thermiques et aux chocs mecaniques des materiaux refractaires utilises dans les fours de traitement de l'aluminium

    NASA Astrophysics Data System (ADS)

    Sebbani, Mohamed Jamal Eddine

    2001-07-01

    This work is a theoretical and experimental study of the correlation between the resistance to thermal shock and mechanical shock of refractory materials. The study of thermal shock showed that the Bahr and Hasselman approaches are alike and that they can be combined into a single, more general approach. This generalisation allowed the division of the theoretical models into two groups: the Hasselman model and the Harmuth model. However, neither of these approaches can predict the behaviour of all refractory materials submitted to thermal shock. Therefore, the generalisation of the Hasselman approach is more appropriate for more dense materials while the Hartmuth approach is more appropriate for less dense materials. The influence of porosity on the energy of rupture helped to explain the behaviour of the less dense material. The absence of generalisation in this case allows those parameters that could be correlated with thermal shock resistance to be dependent on the type of refractory. The study of mechanical shock provided a better understanding of this mechanism. The work performed showed, theoretically and experimentally, that the resistance of the refractory materials could be correlated with the parameter s20 Egwof n-22 . This new parameter helped to explain the statistical correlation between the resistance to mechanical impact and the soxRst parameter established in earlier work. The sintering influence, which makes the refractories more resistant to this type of demand, notably by reducing the "n" coefficient, was shown. This part of the study allowed the establishment of equivalence between thermal fatigue and fatigue by mechanical impact. An evaluation of the correlation between the two mechanisms demonstrated, theoretically and experimentally, that the mechanical and thermal demands could only be exceptionally correlated. In the case of thermal shock, which are imposed deformation demands, it is the shorter cracks which are the most dangerous. However, in the case of mechanical shock, which is constraint imposed, it is the longer cracks that are the most harmful. (Abstract shortened by UMI.)

  20. Simulation du comportement thermique en régime permanent d'un moteur asynchrone à refroidissement extérieur. Etude par éléments finis

    NASA Astrophysics Data System (ADS)

    Glises, R.; Hostache, G.; Kauffmann, J. M.

    1994-09-01

    The steady state thermal modelling of an 4kW asynchronous motor is realized. A design has been made thanks to the Flux2D finite element magnetic calculus software converted into a resolution tool of the heat equation. This last is used to simulate the heat flux in fluid and solid areas. A 3D study is effected thanks to two 2D studies. The first concerns a radial view (perpendicular to the mechanical axis) whereas the second is effected for an axial view (parallel to the mechanical axis). Thermal conductivities of the materials and thermal contact resistances of the motor are determined through two different tests creating different overheatings. The first is made with a sinewave supply and pre-determine the thermophysical parameters. The second effected with direct current supplies at the rotor and the stator is used to validate these last parameters. On réalise l'étude du comportement thermique en régime permanent d'un moteur asynchrone de 4kW. Le logiciel de calculs magnétiques par éléments finis flux2D est converti en un outil de résolution de l'équation de la chaleur. Cette dernière équation sert à simuler les transferts thermiques tant dans les domaines fluides que solides. Une pseudo-étude tridimensionnelle est réalisée par le biais de deux études bidimensionnelles : la première effectuée suivant un plan radial (plan perpendiculaire à l'axe du moteur) et la seconde suivant un plan axial (plan parallèle à l'axe). Les conductivités des matériaux et des résistances thermiques de contact composant le moteur sont déterminées à l'aide de deux types d'essais qui induisent des échauffements différents. Le premier est réalisé avec une alimentation sinusoïdale et sert à prédéterminer les paramètres thermophysiques. Le second est effectué avec des alimentations à courant continu tant au stator qu'au rotor et a pour rôle la validation de ces paramètres.

  1. ETUDE QUANTITATIVE PAR RADIOAUTOGRAPHIE AU MICROSCOPE ELECTRONIQUE DE L'UTILISATION DE LA DL-LEUCINE-3H PAR LES CELLULES DE L'HYPOPHYSE DU CANARD EN CULTURE ORGANOTYPIQE

    PubMed Central

    Tixier-Vidal, A.; Picart, R.

    1967-01-01

    The synthesis, intracellular transport, storing, and excretion of proteins by duck hypophyseal cells in organ culture were studied with tritiated DL-leucine and high resolution radioautography (pulse-labeling experiments). Quantitative study of the radioautographs allowed a determination of the relative proportions of cytoplasmic radioactivity located in each cellular compartment (ergastoplasm, Golgi apparatus, and protein granules) as well as the variations in these proportions as a function of time. The number of labeled protein granules as opposed to the total number of granules in the cell was also determined (RSg). These data were separately analyzed for the two types of cells present in the explants: prolactin cells and "MSH" cells. The synthetic process follows a course common to both cell types, each of which is distinguished by its particular modalities. The labeled proteins, synthesized within several minutes in the ergastoplasm, are concentrated in the Golgi zone within 30 min. They then migrate out of this area, the emptying of which is accomplished in about 4 hr. These proteins become equally distributed between the protein granules, on the one hand, and the cytoplasm ("sedentary" proteins), on the other. The RSg reaches its maximum when the Golgi zone is emptied, but this figure remains very low (3%). The RSg then decreases slowly (1% in 40 hr). It is concluded that hypophyseal cells are able to store protein in their granules and that their processes of synthesis and excretion are not continuous. The prolactin cells differ from the "MSH" cells in that they have a slower migration of newly synthesized proteins, and these proteins pass via the dilated ergastoplasmic cisterns in which they may possibly be stored. PMID:6064363

  2. Proceedings of the 2009 Annual Meeting of the Canadian Mathematics Education Study Group = Actes de la Rencontre Annuelle 2009 du Groupe Canadien d'Etude en Didactique des Mathematiques (33rd, Toronto, Ontario, Canada, June 5-June 9, 2009)

    ERIC Educational Resources Information Center

    Liljedahl, Peter, Ed.; Oesterle, Susan, Ed.; Abu-Bakare, Veda, Ed.

    2010-01-01

    This submission contains the Proceedings of the 2009 Annual Meeting of the Canadian Mathematics Education Study Group (CMESG), held at York University in Toronto, Ontario. The CMESG is a group of mathematicians and mathematics educators who meet annually to discuss mathematics education issues at all levels of learning. The aims of the Study Group…

  3. Home Economics/Family Studies Education in Canadian Schools: A Position Paper = L'enseignement de l'economie familiale/etudes familiales dans les ecoles canadiennes: Expose de principes.

    ERIC Educational Resources Information Center

    Canadian Home Economics Journal, 1996

    1996-01-01

    English and French versions of the Canadian Home Economics Association's position paper describe the place of home economics/family studies (HEFS) in education and worldwide trends indicating the need for HEFS. Suggests it is the only subject with the primary focus on preparing students for everyday life in an increasingly complex global society.…

  4. A Study of the Teaching and Learning Styles in Ontario Schools=Une Etude des Styles d'Enseignement et d'Apprentissage dans les Ecoles de l'Ontario.

    ERIC Educational Resources Information Center

    Rancourt, Richard; Dionne, Jean-Paul

    Psycho-epistemology provides a framework for this study on interrelationships among teachers, subject matter, and learners. Chapter 1 presents the polemics that lead to the problem, including sections on educational divergence, the noncumulative nature of knowledge in education, the divergence of opinion regarding the "best" teaching and…

  5. Double protection passive pour les equipages de l’helicoptere d’attaque "Tigre" : Concept et etude experimentale (Design and Experimental Study of the Passive Double Hearing Protection for the Crew of the Attack Helicopter "Tiger")

    DTIC Science & Technology

    2005-04-01

    propre, la protection complémentaire offerte par les bouchons d’oreille passifs s’est naturellement imposée comme axe de travail. Préalablement évalués... naturelle de la tête et réduire les risques de cervicalgies et de fatigue. Le respect de ces critères amène naturellement le concepteur à alléger...nombre de coups tirés durant le vol, voire 24 heures. L’utilisation d’armes est naturellement limitée dans le temps, même pour une mission de combat. On

  6. Etude épidémio-clinique des diarrhées aiguës à rotavirus chez les nourrissons à l'hôpital Jason Sendwe de Lubumbashi, République Démocratique du Congo

    PubMed Central

    Sangaji, Maguy Kabuya; Mukuku, Olivier; Mutombo, Augustin Mulangu; Mawaw, Paul Makan; Swana, Edouard Kawawa; Kabulo, Benjamin Kasongo; Mutombo, André Kabamba; Wembonyama, Stanis Okitotsho; Luboya, Oscar Numbi

    2015-01-01

    Introduction Le rotavirus est un problème de santé publique, non seulement dans les pays en développement où tous les enfants sont infectés avant l’âge de deux à trois ans mais aussi dans les pays développés où les conditions d'hygiène sont bonnes. La présente étude est la première à fournir des informations sur la prévalence de l'infection à rotavirus dans les diarrhées aiguës des nourrissons dans la ville de Lubumbashi. Elle s'est fixée comme objectifs de déterminer la fréquence hospitalière ainsi que la saisonnalité, les caractéristiques sociodémographiques, cliniques et évolutives de l'infection à Rotavirus chez les nourrissons admis à l'hôpital Jason Sendwe de Lubumbashi pour une diarrhée aiguë. Méthodes Il s'agit d'une étude descriptive et transversale menée pendant la période allant du 1er janvier au 31 décembre 2012. Les paramètres épidémio-cliniques et évolutifs (âge, sexe, saison, signes cliniques, nombre journalier de selles et évolution) des enfants diagnostiqués positifs au rotavirus ont été comparés à ceux des enfants dont le test au rotavirus était négatif. Le degré de signification était de 5%. Résultats Nous avons récolté 193 cas de diarrhées aiguës dont 104 nourrissons étaient infectés par le rotavirus soit 53,8%. Des taux élevés des diarrhées à rotavirus sont enregistrés au cours de la saison sèche comparativement à la saison des pluies (p0,05). Par ailleurs, les enfants infectés par le rotavirus étaient 6 fois plus susceptibles de présenter une déshydratation modérée/sévère (p0,05). Conclusion Le rotavirus est confirmé dans la ville de Lubumbashi et touche souvent les enfants d’âge ≤12 mois, pendant la saison sèche sans distinction de sexe et conduit rapidement à une déshydratation modérée/sévère. Une prise en charge adaptée et précoce permet d’éviter les décès et l'assainissement du milieu, le lavage des mains, la prise d'eau potable et la vaccination contre le rotavirus sont les mesures préventives les plus efficaces contre les rotavirus et à conseiller dans notre communauté. PMID:26327950

  7. Development and validation of an endoscopic index of the severity for Crohn's disease: a prospective multicentre study. Groupe d'Etudes Thérapeutiques des Affections Inflammatoires du Tube Digestif (GETAID).

    PubMed Central

    Mary, J Y; Modigliani, R

    1989-01-01

    The aim of this study was to develop and validate an endoscopic index for assessing the severity of Crohn's disease. Endoscopic findings were prospectively collected by a multicentre group in 75 patients with Crohn's colitis according to a previously validated procedure. The presence of nine preselected lesions was recorded in the following segments (1) rectum, (2) sigmoid and left colon, (3) transverse colon, (4) right colon, and (5) ileum. In addition the extent of the diseased and ulcerated areas were estimated in each segment. These segmental data were recorded on a standard form, together with the endoscopist's global estimate of lesion severity. A stepwise multiple regression was used to derive an index which was correlated with the endoscopist's global evaluation of lesion severity. Four mucosal lesions: deep and superficial ulcerations, ulcerated and non-ulcerated stenosis, and both estimates of extent involved were selected and weighted to obtain a Crohn's Disease Endoscopic Index of Severity which correlated with the endoscopist's global appraisal of lesion severity (r = 0.83). This index was then prospectively shown to be valid in a further series of 113 colonoscopies (r = 0.81). The index was calculated in 54 patients with active Crohn's disease, before and at the end of a course of corticosteroids: index variations correctly reflected changes in colitis severity as evaluated by the endoscopists (r = 0.72). For endoscopists familiar with the data collection procedure, this Crohn's Disease Endoscopic Index of Severity should be of value in the follow up of patients, especially in clinical trials. PMID:2668130

  8. Etude des connaissances, attitudes et pratiques en matière de réintégration sociale des femmes victimes de fistule obstétricale: région de l'Extrême-nord, Cameroun

    PubMed Central

    Martin, Sanou Sobze; Adogaye, Sali Ben Béchir; Rodrigue, Mabvouna Biguioh; Maurice, Douryang; Vivaldi, Teikeu Tessa Vladimir; Amede, Saah Fopa Michael; Marie, Ovaga Eyenga Landry; Meriam, Ausseil Sandra; Colizzi, Vittorio; Gianluca, Russo

    2015-01-01

    Introduction La fistule obstétricale est un orifice entre le vagin et la vessie ou le rectum, voire les deux. Ses impacts sont des conséquences anatomo-fonctionnelles et sociales. On estime à plus de 19 000 le nombre de femmes qui souffrent de fistule obstétricale au Cameroun. Méthodes Il s'agissait d'une étude transversale descriptive conduite dans trois districts de santé de la région de l'Extrême-nord. Vingt-huit femmes victimes de fistules obstétricales, quarante-deux membres de leur entourage et vingt-quatre agents de santé ont été interviewés entre Novembre et Décembre 2013. Trois types de questionnaires ont été utilisés. Les données ont été analysées dans Epi Info version 7.1.4.0. Les moyennes et les fréquences ont été calculées avec un intervalle de confiance à 95%. Résultats 46,4% des femmes victimes de fistule obstétricales interviewées avaient subi une intervention chirurgicale réparatrice parmi lesquelles, 61,5% bénéficiaient de la réintégration. Le fonds de commerce (62,5%) était l'aide la plus reçue. Vingt-deux membres de l'entourage savaient pourquoi on fait la réintégration. Selon eux, les considérations socioculturelles (68,2%), sont la principale barrière de la réintégration. D'après les agents de santé, le suivi psychosocial (58,3%) est la principale activité de la réintégration dans les centres de prise en charge de la fistule. Conclusion La prise en charge des fistules obstétricales au Cameroun souffre de manque de réintégration sociale. Ceci expliquerait en partie la persistance de cette pathologie. Un accent devrait être mis sur l'appui matériel, financier et sur le suivi psychosocial des femmes victimes de fistule obstétricale. PMID:26113915

  9. Etude de facteurs de risque de la transmission du VIH de la mère à l'enfant dans la stratégie « option A » à Lubumbashi, République Démocratique du Congo

    PubMed Central

    Ngwej, Dieudonné Tshikwej; Mukuku, Olivier; Mudekereza, Rachel; Karaj, Eugénie; Odimba, Etienne Bwana Fwamba; Luboya, Oscar Numbi; Kakoma, Jean-Baptiste Sakatolo; Wembonyama, Stanis Okitotshio

    2015-01-01

    Introduction L'infection à VIH chez la femme enceinte a pour principal risque la contamination du nouveau-né. L'objectif est de déterminer le taux de transmission du VIH de la mère à l'enfant (TME) dans la ville de Lubumbashi et en évaluer les facteurs de risque. Méthodes Il s'agissait d'une étude prospective transversale à visée analytique de 157 accouchées séropositives au VIH et de leurs enfants dans 12 structures sanitaires de Lubumbashi (RDCongo) du 1er octobre 2012 au 31 décembre 2013. Les paramètres sociodémographiques, cliniques et les données relatives aux activités de PTME du VIH ont été étudiés. Les statistiques usuelles ont été utilisées pour analyser les résultats. Le seuil de significativité a été fixé à une valeur de p < 0,05. Résultats Le taux de transmission verticale du VIH était de 12,7% (20/157). Il n'y avait pas d'association significative entre les caractéristiques sociodémographiques maternelles telles que l’âge, la parité, le niveau d’étude, la profession et l’état-civil et la TME (p>0,05). La transmission verticale du VIH était significativement associée aux facteurs suivants: le stade clinique 3 de l'OMS (OR=5,18 (1,5-18,1)), la présence d'infection opportuniste (OR=8,7 (2,7-27,8)), le dépistage lors de l'accouchement (OR=6,3 (1,0-39,0)) ou au cours de l'allaitement (OR=7,1 (1,1-76,7)), au taux de CD4 maternel <350/mm3 (OR=2,9 (1,1-7,7)), l'absence de thérapie antirétrovirale chez la mère (OR=19,9 (4,8-81,9)), la naissance avant terme (OR=4,7 (1,4-16,0)), la rupture prématurée de membranes (OR=45,0 (7,4-454,6)), le faible poids de naissance (OR=5,6 (1,9-16,7)), la notion de réanimation néonatale (OR=12,4 (3,8-40,1)), la non administration de la névirapine à la naissance (OR=26,4 (7,6-92,3)) et l'alimentation mixte (OR=12,6 (1,3-115,9)). Le sexe du nourrisson et le mode d'accouchement n’étaient pas non plus associés à la transmission verticale du VIH (p>0,05). Conclusion Le taux de TME du VIH demeure fort élevé à Lubumbashi comme dans la plupart de pays en développement où les nouveau-nés continuent d’être infectés par le VIH de manière verticale alors que certains facteurs de transmission sont tout à fait souvent évitables. La réduction de cette transmission passe par une amélioration du système de suivi des grossesses dans notre milieu. PMID:26600917

  10. Le langage des "gendarmes" et des "voleurs": etude comparative du vocabulaire de la pegre et de la police en francais et en anglais ("Cops" and "Robbers" Language: A Comparative Study of the Underworld and Police Vocabulary of French and English).

    ERIC Educational Resources Information Center

    Brunet, Jean-Paul

    1981-01-01

    Discusses the meaning and origins of the word "argot," its cryptic character, and its function in a closed social group, focusing on a comparative description of the French and Anglo-American vocabulary of the underworld and the police. Comments on shared traits and provides an insight into the differences. (MES)

  11. Etude du revenu de l'acier z 10 CDNbV0902 (type 9% Cr, 2% Mo + Nb,V) envisage pour la realisation de certains composants des reacteurs a neutrons rapides

    NASA Astrophysics Data System (ADS)

    Pelletier, M.; Vilar, R. M.; Cizeron, G.

    1982-02-01

    Après trempe depuis 1100°C, l'acier étudié est formé de ferrite stable à haute température et de martensite. Au cours de revenus anisothermes, la phase martensitique est le siège de la précipitation successive de carbures des types M 3C, M 7C 3 et M 2C, ces deux derniers étant responsables d'un durcissement secondaire significatif. Aux températures plus élevées, ces carbures se dissolvent tandis qu'apparaissent des carbures des types M 23C 6 et M 6C. La phase ferritique initialement sursaturée est, par ailleurs, le siège d'une précipitation de carbures des types M 2C et M 23C 6.

  12. Etude experimentale de l'effet de rochet de traction-torsion d'un acier inoxydable 17-12 Mo-SPH, de 20 A 650° C

    NASA Astrophysics Data System (ADS)

    Delobelle, P.

    1989-08-01

    Le but du presént article est 1'étude expérimentale du phénomèna de rochet 2D de traction-torsion, essai non proportionnel particulièrement riche en informations et très peu étudié. La séquence expérimentale consiste en l'application d'une faible contrainte secondaire de traction et en la superposition d'une déformation cyclique, d'amplitude maximale constante, pour une vitesse et une isotherme fixées. Nous avons étudie 1'ensemble des caractéristiques de ce chargement, à savoir, l'effet de la contrainte axiale σ zz, de l'amplitude de la déformation {Δɛ zθT}/{2}, de la vitesse de déformation ge zθT et de la température T. On identifie des mécanismes d'interaction dislocations-défauts ponctuels pour le domaine des températures intermédiaires. En conclusion, ce type d'essai réalise une synthèse des difficultés que l'on peut rencontrer lors de la modélisation, presque tous les effets (en dehors de l'anisotropie initiate) étant présents et intimement liés: comportement viscoplastique, effet de normalité, de mémoire évanescente de l'histoire antérieure, du temps, de la température, de la configuration des défauts ponctuels, de contrainte moyenne et enfin, à plus haute température, de précipitation à longue distance.

  13. Etude de la migration des interstitiels dans des austenites Fe, Cr (18), Ni (14) pures et industrielles par irradiation dans un microscope a tres haute tension: Role du carbone et du titane

    NASA Astrophysics Data System (ADS)

    Housseau, N.; Pelissier, J.

    1983-12-01

    Nous avons étudié le rôle des impurtés (C ou Ti) dans la condensation et la migration des défauts interstitiels. Les échantillons étudiés sont des aciers austénitiques: (a) acier de synthèse de haute pureté (Cr 18, Ni 14, Fe) avec ou sans carbone; (b) acier industriel avec C (800 ppm) ou Ti (0,45%). Les échantillons ont été irradiés dans un microscope à très haute tension aux doses allant de 10 -4 jusqu'à 10 -1 dpa aux températures de 300°C à 400°C. Dans de telles conditions les défauts observés sont des boucles interstitielles. L'étude de la variation de l'épaisseur de la zone dénudée près du bord de la lame mince en fonction de la température nous a permis d'évaluer l'énergie de migration effective de l'interstitiel dans ces alliages. Dans l'austénite de synthèse carburée ou non sa valeur est de 0.8 eV. Dans l'acier industriel au titane carburé ou non on obtient 2.0 eV. Nous n'avons pas observé d'effet lié au carbone. L'examen de la densité de boucles à saturation dans les divers aciers suggère une forte énergie de liaison interstitiel-titane. Cette énergie de liaison, si l'ont admet que le titane est la seule impureté agissante du système, peut être estimée à 1.2 eV.

  14. Etude analytique et numérique de la réponse en vibration à hautes fréquences d'éprouvettes de fatigue vibratoire des métaux. Application aux aciers

    NASA Astrophysics Data System (ADS)

    Ben Aich, A.; El Kihel, B.; Kifani, A.; Sahban, F.

    1994-07-01

    In the present paper, the so-called " ultrasonic fatigue " or fatigue at very high frequency has been studied in the materials elastic behaviour case while neglecting the thermal effects that influence the mechanical fields. The determination of mechanical fields and specimen resonance length has been done both analytically and numerically. The numerical method used for this calculation is the finite element method (FEM). Martensitic steel " Soleil A2 " and austenitic steel " ICL 472 BC " have been considered in order to compare the two methods (analytical and numerical). It is shown that a perfect convergence is obtained between the two solutions. Dans le présent travail, la fatigue vibratoire a été étudiée dans le cas du comportement élastique des matériaux en négligeant les effets thermiques pouvant influencer les champs mécaniques. La détermination de ces champs et de la longueur de résonance des éprouvettes de fatigue a été faite analytiquement et numériquement. Le calcul numérique effectué se base sur la méthode des éléments finis. Dans le but d'une comparaison des solutions analytiques et numériques, deux aciers ont été considérés : un acier martensitique (Soleil A2) et un acier austénitique de type 18-10 (ICL 472 BC). Une parfaite convergence est obtenue entre les deux solutions.

  15. Canadian Mathematics Education Study Group = Groupe Canadien d'Etude en Didactique des Mathematiques. Proceedings of the Annual Meeting (24th, Montreal, Quebec, Canada, May 26-30, 2000).

    ERIC Educational Resources Information Center

    Simmt, Elaine, Ed.; Davis, Brent, Ed.; McLoughlin, John Grant, Ed.

    This document contains the proceedings of the annual meeting of the Canadian Mathematics Education Study Group (CMESG) held at the University of Quebec in Montreal, Canada, May 26-30, 2000. The proceedings consist of two plenary lectures, five working groups, four topic sessions, new Ph.D. reports, and panel discussions. Papers include: (1)…

  16. Une epreuve orale de francais en fin d'etudes de gestion. Construction et implications pedagogiques (An Oral French Exam at the End of a Marketing Program. Construction and Pedagogical Implications).

    ERIC Educational Resources Information Center

    Crawshaw, Robert H.

    1984-01-01

    An oral language test administered at the end of a four-year program combining business administration and French is described. The test consists of the formal presentation of a report including numbers, graphics, and text, a discussion of a theoretical issue, and interview. (MSE)

  17. Etude et simulation du protocole TTEthernet sur un sous-systeme de gestion de vols et adaptation de la planification des tâches a des fins de simulation

    NASA Astrophysics Data System (ADS)

    Abidi, Dhafer

    TTEthernet is a deterministic network technology that makes enhancements to Layer 2 Quality-of-Service (QoS) for Ethernet. The components that implement its services enrich the Ethernet functionality with distributed fault-tolerant synchronization, robust temporal partitioning bandwidth and synchronous communication with fixed latency and low jitter. TTEthernet services can facilitate the design of scalable, robust, less complex distributed systems and architectures tolerant to faults. Simulation is nowadays an essential step in critical systems design process and represents a valuable support for validation and performance evaluation. CoRE4INET is a project bringing together all TTEthernet simulation models currently available. It is based on the extension of models of OMNeT ++ INET framework. Our objective is to study and simulate the TTEthernet protocol on a flight management subsystem (FMS). The idea is to use CoRE4INET to design the simulation model of the target system. The problem is that CoRE4INET does not offer a task scheduling tool for TTEthernet network. To overcome this problem we propose an adaptation for simulation purposes of a task scheduling approach based on formal specification of network constraints. The use of Yices solver allowed the translation of the formal specification into an executable program to generate the desired transmission plan. A case study allowed us at the end to assess the impact of the arrangement of Time-Triggered frames offsets on the performance of each type of the system traffic.

  18. A Survey of Serious Aircraft Accidents Involving Fatigue Fracture. Volume 1. Fixed-Wing Aircraft (Etude sur des Accidents Importants d’Avions du aux Effets des Fractures de Fatigue. Volume 1. Effets sur des Avions).

    DTIC Science & Technology

    1983-04-01

    of Civil Aviation, Malta. Mario Bantamaria Junta de Investig. Accidentes de Aviacion , Argentina. -%7- * * %7 r . - .. w - 14 Dr. Boonsorn Boonsukha...Aviation Organization, Montreal Canada. Ing. Guillermo Oficina de Investigacion de Accidentes de Aviacion , Leyva Galindo Mexico. Dr. G.H. Gessinger

  19. Etude théorique des paramètres principaux réglant la sensibilité des capteurs d'accélération à cristal de quartz

    NASA Astrophysics Data System (ADS)

    Delaite, R.; Aïch, Y.

    1994-10-01

    A theoretical analysis of quartz accelerometers is performed to determine their optimal mechanical and sensitivity performances. A general analytical model is used to investigate the parameters and their effects on the sensitivity of these sensors. The analysis of physical characteristics shows that feasibility and performances depend on three factors such as dimensions of the quartz plate, quantity of holders located at the crystal edge and location of these holders with respect to the crystal's crystallographic reference. This study is applied to various design sensors with different supporting quartz crystal. The conditions on parameters are given to achieve optimum performances. Une étude théorique de la sensibilité des capteurs d'accélération à cristal de quartz est présentée. Son but est d'optimiser les performances mécaniques et métrologiques de ces capteurs. Les paramètres sensibles sont mis en évidence. L'analyse des caractéristiques physiques démontre que la faisabilité et les performances des accéléromètres à quartz dépendent, pour une coupe donnée du cristal, de trois facteurs : les dimensions de la lame de quartz, le nombre de liaisons à la périphérie du cristal et la position de ces liaisons par rapport à la référence cristallographique. L'étude est appliquée aux cas des capteurs bipodes, multipodes et monopodes. Pour chaque type de capteur, les valeurs des paramètres sensibles correspondant aux performances optimales sont précisées.

  20. Etudes des verres du pseudo-ternaire La 2S 3Bi 2S 3Ga 2S 3, en relation avec le diagramme de phases et la spectroscopie infra-rouge

    NASA Astrophysics Data System (ADS)

    Ecrepont, C.; Guittard, M.; Barnier, S.; Loireau-Lozac'h, A. M.; Palazzi, M.; Julien, C.; Massot, M.

    1992-04-01

    The phase diagram of the La 2S 3Ga 2S 3Bi 2S 3 ternary system is described. DTA measurements have been carried out on a large variety of glass, and the glass formation domain has been defined with the investigation of Tg, Tc, and the endothermic peaks. Infrared absorption spectra have been studied. The vibrational assignment is discussed in relation to the composition of the glass.

  1. Enquetes sur Differents Aspects de la Vie Sociale a Rennes et en Bretagne. Rapports des Groupes d'Etudes (Inquiries into Various Aspects of the Social Life at Rennes and in Brittany. Reports of Study Groups).

    ERIC Educational Resources Information Center

    Saint Catherine Coll., St. Paul, Minn.

    This collection of reports on French civilization represents the efforts of several teams of students participating in the 1964 NDEA summer institute at Rennes, France. As a partial requirement for the civilization course, the groups submitted field study reports of the cultural life at Rennes and Brittany including: (1) environment and…

  2. A Survey of Serious Aircraft Accidents Involving Fatigue Fracture. Volume 2. Rotary-Wing Aircraft (Etude sur des Accidents Importants d’Avions du aux Effets des Fractures de Fatigue. Volume 2. Effets sur des Helicopteres).

    DTIC Science & Technology

    1983-04-01

    12 Aug 78 0 S Soledad , Cal. USA. Tail rotor blade at insert on shank. Ref: NTSB file 3-2427. K80 Bell 47G-2 12 Aug 78 1 D Omega, Georgia USA. Tail...Tenn. USA. Tail rotor blade grip P/N 47-642-102. In service 468 hours. K79 Bell 47G-2 12 Aug 78 0 S Soledad , Cal. USA. Tail rotor blade (PN 47-642-K02

  3. The Relationship Between Non-Governmental Organizations and the Canadian Forces: A Pilot Study (La relation entre les organisations non-gouvernementales et les forces canadiennes: Une etude pilote)

    DTIC Science & Technology

    2010-09-01

    organizations from which to draw participants include a broader range of NGOs, international organizations (IOs), as well as other government departments (OGDs...such as the Royal Canadian Mounted Police (RCMP), the Canadian International Development Agency (CIDA), and the Department of Foreign Affairs and... International Trade (DFAIT), paid contractors, and other development groups all of which are involved in the theatre of operations. Within the CF, a

  4. Etude séro-epidémiologique de trois infections sexuellement transmissibles (Chlamydia Trachomatis, Hépatite B, Syphilis): cas de l’Hôpital de District de Nkoldongo à Yaoundé

    PubMed Central

    Essome, Marie Chantal Ngonde; Nsawir, Bonglaisin Julius; Nana, Rodrigue Dongang; Molu, Patrick; Mohamadou, Mansour

    2016-01-01

    Introduction Les infections sexuellement transmissibles sévissent toujours dans les pays en voie de développement et particulièrement au Cameroun. Le but de notre étude est de déterminer la distribution des infections sexuellement transmissibles suivantes: l’hépatite virale B, le Chlamydia trachomatis et de la syphilis dans une population de femmes venant consulter spontanément à l’Hôpital de District de Nkoldongo à Yaoundé, d’évaluer d’éventuelles coïnfections entre ces trois affections et de ressortir les connaissances de ces femmes sur leur mode de transmission sexuelle. Méthodes Notre étude prospective et descriptive a porté sur 182 femmes dont l’âge variait entre 18 et 48 ans. Les femmes ont été testées sérologiquement pour le Chlamydia trachomatis par une méthode ELISA (kit des laboratoires General Biological Corp). L’hépatite virale B a été dépistée par une méthode immunochromatographique (kit des laboratoires Human) et la syphilis par une méthode d’agglutination en ce qui concerne le RPR (Kit des laboratoires Biocentric) et le TPHA (kit des laboratoires Human). Résultats Nos résultats ont montré que: la distribution du Chlamydia trachomatis, de l’hépatite virale B et la syphilis a été respectivement de 22,52%, 4,39%, 0,54%.De plus, nous avons observé une coinfection Chlamydia trachomatis hépatite virale B avec un taux de 2,74%. Par ailleurs la réinfection au Chlamydia trachomatis a été rencontrée dans 4,94% de cas. S’agissant du mode de transmission de ces affections 67,57% et 70,87% de femmes ne connaissaient pas la voie de transmission sexuelle pour le Chlamydia trachomatis et pour l’hépatite virale B respectivement, tandis que 91,2 % des femmes connaissaient la voie de transmission sexuelle pour la syphilis. Conclusion Le diagnostic d’une infection à Chlamydia trachomatis chez une patiente doit susciter le dépistage de l’hépatite virale B. Introduction Sexually transmitted infections are still frequent in developing countries and particularly in Cameroon. The aim of this study was to determine the distribution of the following sexually transmitted infections: viral hepatitis B, Chlamydia trachomatis and syphilis in a population of women spontaneously visiting the Nkoldongo District Hospital in Yaoundé as well as to evaluate possible co-infections among these three conditions and to bring out women’s prior knowledge of how sexual transmission occurs. Methods We conducted a prospective and descriptive study including 182 women aged between 18 and 48 years. These women underwent serologic testing for Chlamydia trachomatis with ELISA (General Biological Corp laboratory test kit. Hepatitis B virus was detected using immunochromatographic method (Human laboratory kit) while syphilis was detected using RPR agglutination (Biocentric Laboratories kit )and TPHA agglutination (Human laboratory kit) method. Results Our results showed that the distribution of Chlamydia trachomatis, viral hepatitis B and syphilis was 22.52%, 4.39%, 0.54% respectively. Moreover, we reported a Chlamydia trachomatis and Viral hepatitis B coinfection rate of 2.74%. In addition, Chlamydia trachomatis reinfection was detected in 4.94% of cases. Regarding the mode of transmission of these infections, 67.57% and 70.87% of women didn’t know how Chlamydia trachomatis and viral hepatitis sexual transmission could occur respectively, while 91.2% of women knew how was syphilis spread. Conclusion The diagnosis of chlamydia trachomatis infection should prompt screening for viral hepatitis B. PMID:28293360

  5. A Survey of Blast Injury across the Full Landscape of Military Science (Etude d’ensemble des blessures dues aux explosions a travers le panorama complet de la science militaire)

    DTIC Science & Technology

    2011-04-01

    PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION...advice to NATO and national decision makers. The RTO performs its mission with the support of an extensive network of national experts. It also ensures...the form of one or more new task groups and/or workshops to address, at a minimum: 1) Methods for blast incident reconstruction and analysis where

  6. Etude des défauts profonds dans l'arséniure de gallium implantés en oxygène et co-implantés en silicium par la méthode FTDLTS

    NASA Astrophysics Data System (ADS)

    Le Bloa, A.; Tran Quan, Dang; Guennouni, Z.; Favennec, P. N.

    1994-06-01

    We describe the setting up of our isotherm FTDLTS (Fourier Transform Deep Level Transient Spectroscopy) method which has a better time constant resolution than that of classic DLTS methods. This method has been used to characterize deep levels in O-implanted and (O + Si) co-implanted GaAs. Several deep centers with closely-spaced levels of the U band and the EL2 family levels have been characterized. Discret levels have been obtained. The signatures of these defects are closed, in the first case, to that of the EL3 center, in the second case, to that of the EL0 and EL2 centers. The (Ea= 0.56 eV) level seems to be the Ga-O-Ga complex. The (O + Si) co-implantation favors the ED2 defect formation in 650 ^{circ}C and 900 ^{circ}C annealed samples. On rappelle d'abord la mise en oeuvre d'une nouvelle méthode isotherme appelée FTDLTS (Fourier Transform Deep Level Transient Spectroscopy) dont le pouvoir séparateur en constante de temps est nettement supérieur à celui des méthodes DLTS classiques. On l'applique à la caractérisation des défauts profonds, dans le domaine de températures 200-450 K, des échantillons de GaAs implantés en oxygène et en silicium. Plusieurs défauts à niveau d'énergie discret appartenant à la bande U et dont les signatures, toutes proches de celle de EL3, sont voisines ont été mis en évidence. L'un de ces défauts (Ea = 0,56 eV) semble être le défaut complexe Ga-O-Ga. Trois défauts EDI, ED2 et ED3 de la famille EL2 ont été également mis en évidence ; deux d'entre eux, ED2 et ED3 ont une signature proche de celle de EL0 et EL2 respectivement. La co-implantation de silicium avec l'oxygène favorise, dans nos échantillons recuits à 650 ^{circ}C et à 900 ^{circ}C, la formation de ED2 par rapport à celle de ED1.

  7. Linguistic Insights in Applied Linguistics. Collection d'"Etudes linguistiques," No. 14. Papers from the Neuchatel Colloquium in Applied Linguistics in collaboration with AIMAV, AILA, CILA, and the University of Neuchatel (2nd, May 25-26, 1973).

    ERIC Educational Resources Information Center

    Corder, S. P., Ed.; Roulet, E., Ed.

    Papers from the 1973 Neuchatel Colloquium in Applied Linguistics are presented. Contents are as follows: "Karttunen's Types of Implication in English and German: A Contrastive Study," W. Abraham; "The Relevance of Generative Semantics for Language Teaching," R. Dirven; "'Be' plus 'ing' Revisited," H. Adamczeski; "The So-Called Deep Structures and…

  8. Canadian Mathematics Education Study Group (Groupe Canadien D'etude en Didactique des Mathematiques). Proceedings of the Study Group Meeting (10th, St. John's, Newfoundland, Canada, June 8-12, 1986).

    ERIC Educational Resources Information Center

    Verhille, Charles, Ed.

    These proceedings contain lectures concerned with problem solving, applications of undergraduate mathematics, and aspects of current research in mathematics. The four working groups considered: (1) the role of feelings in learning mathematics; (2) the problem of rigor in mathematics teaching; (3) microcomputers in teacher education; and (4) the…

  9. Proceedings of the 2008 Annual Meeting of the Canadian Mathematics Education Study Group = Actes de la Rencontre Annuelle 2008 du Groupe Canadien d'Etude en Didactique des Mathematiques (32nd, Sherbrooke, Quebec, Canada, May 23-27, 2008)

    ERIC Educational Resources Information Center

    Liljedahl, Peter, Ed.; Oesterle, Susan, Ed.; Berneche, Christian, Ed.

    2009-01-01

    This submission contains the Proceedings of the 2008 Annual Meeting of the Canadian Mathematics Education Study Group (CMESG), held at the Universite de Sherbrooke in Sherbrooke, Quebec. The CMESG is a group of mathematicians and mathematics educators who meet annually to discuss mathematics education issues at all levels of learning. The aims of…

  10. Canadian Mathematics Education Study Group = Groupe Canadien d'etude en didactique des mathematiques. Proceedings of the Annual Meeting (22nd, Vancouver, British Columbia, Canada, May 29-June 2, 1998).

    ERIC Educational Resources Information Center

    Pothier, Yvonne M., Ed.

    This proceedings includes the following papers: (1) "Structure of Attention in Teaching Mathematics" (John Mason); (2) "Communicating Mathematics or Mathematics Storytelling" (Kathy Heinrich); (3) "Assessing Mathematical Thinking" (Florence Glanfield and Pat Rogers); (4) "From Theory to Observational Data (and…

  11. Proceedings of the 2003 Annual Meeting of the Canadian Mathematics Education Study Group = Actes de la Rencontre Annuelle 2003 du Groupe Canadien d'Etude en Didactique des Mathematiques (27th, Wolfville, Nova Scotia, Canada, May 30-June 3, 2003)

    ERIC Educational Resources Information Center

    Simmt, Elaine, Ed.; Davis, Brent, Ed.

    2004-01-01

    This submission contains the Proceedings of the 2003 Annual Meeting of the Canadian Mathematics Education Study Group (CMESG), held at Acadia University in Wolfville, Nova Scotia. The CMESG is a group of mathematicians and mathematics educators who meet annually to discuss mathematics education issues at all levels of learning. The aims of the…

  12. Etude du strabisme chez des enfants de 0 à 15 ans suivis a Lubumbashi, République Démocratique du Congo: analyse des aspects épidémiologiques et cliniques

    PubMed Central

    Bienvenu, Yogolelo Asani; Angel, Musau Nkola; Sebastien, Mbuyi Musanzayi; Philippe, Cilundika Mulenga; Léon, Kabamba Ngombe; Eugene, Twite Kabange; Chami, Cham Lubamba; Prosper, Kalenga Muenze Kayamba; Claude, Speeg-Schatz; Gaby, Chenge Borasisi

    2015-01-01

    Introduction Le strabisme est défini comme un syndrome à double composante: motrice et sensorielle. Le but de ce travail est de décrire les aspects épidémiologiques et cliniques du strabisme chez l'enfant congolais de 0 à 15 ans dans la ville de Lubumbashi. Méthodes Il s'agit d'une étude descriptive longitudinale sur les aspects épidémiologiques et cliniques du strabisme chez l'enfant congolais de 0 à 15 ans dans la ville de Lubumbashi entre Décembre 2012 à Décembre 2013. Nous avons recueilli l’âge des patients, leur sexe, leur provenance, le type de strabisme, la réfraction, le fond d'oeil, les antécédents (hérédité) ainsi que le type de la déviation strabique observé sur 70 patients. Résultats Nous avons observé 70 cas de strabisme manifeste dont 31 cas (44,28%) étaient dans la tranche d’âge comprise entre 0 et 5 ans. L’âge moyen de nos patients était de 6,7 ans avec une prédominance du sexe féminin, soit 51,42%. Le strabisme était convergent dans 65,71%, divergent dans 30%, et vertical dans 4,28%. Les ésotropies représentaient 65 cas (92,85%), quatre cas (5,71%) avaient un antécédent familial de strabisme au premier degré de parenté, 21 cas (30%) au second degré de parenté, 45 cas (64,28%) n'avaient pas cet antécédent. L'oeil gauche était le plus dominé dans 30% des cas. Les facteurs favorisant le strabisme étaient inconnus dans 54 cas (77,14%). Le strabisme était secondaire à l'hypermétropie chez 32 patients (42,71%). Conclusion La fréquence du strabisme dans la ville de Lubumbashi chez les enfants âgés de 0 à 15 ans est de 0,50%. Comme dans la plupart des études sur le strabisme de l'enfant, c'est l’ésotropie qui est la déviation la plus commune. PMID:26834919

  13. La reconnaissance des acquis experientiels: etude de cas de la politique d'admission des adultes a l'Universite de Laval (Recognition of Experiential Learning: Case Study of the Politics of Adult Admissions to the University of Laval.)

    ERIC Educational Resources Information Center

    Heon, Lucie; And Others

    1986-01-01

    A study of 400 University of Laval adult applicants under its new admission policy suggest that while student age and experience appear to be important factors in gaining admission, they are enhanced by the closeness of the experience to academic or cognitive learning combined with a high school diploma and grades above 65%. (MSE)

  14. Etude structurale des sulfotellurures de terres rares ( LS) 2Te 1 + x ( L = Tb, Dy, Ho, Er, Tm et Y). II. Surstructure des phases ordonnées. Macles d'ordre

    NASA Astrophysics Data System (ADS)

    Ghémard, Geneviève; Etienne, Jean; Schiffmacher, Gérard; Flahaut, Jean

    1982-11-01

    The ( LS) 2Te 1 + x compounds have an orthorhombic subcell, with a layered structure and vacant Te sites, and a monoclinic superstructure ( a = b = 6.658, c = 13.657 Å, γ = 102°43' for (HoS) 2Te 1.34). The order-disorder transition occurs at about 450°C. In the superstructure Te planes between ( L4S) tetrahedra layers are ordered with {B2}/{m} symmetry; however, some sites remain partially vacant. The S atoms conserve mmm symmetry, but the metallic atoms are slightly displaced from their substructure position ( R = 0.037). Ordering occurs so that each Te plane can be oriented in two different ways. Therefore, there are two kinds of domains, with respect to a twinning rule. These domains are observed by direct-imaging high-resolution electronic microscopy and are about 100 Å wide.

  15. Proceedings of the 2010 Annual Meeting of the Canadian Mathematics Education Study Group = Actes de la Rencontre Annuelle 2010 du Groupe Canadien d'Etude en Didactique des Mathematiques (34th, Burnaby, British Columbia, Canada, May 21-25, 2010)

    ERIC Educational Resources Information Center

    Liljedahl, Peter, Ed.; Oesterle, Susan, Ed.; Allan, Darien, Ed.

    2011-01-01

    This submission contains the Proceedings of the 2010 Annual Meeting of the Canadian Mathematics Education Study Group (CMESG), held at Simon Fraser University in Burnaby, British Columbia. The CMESG is a group of mathematicians and mathematics educators who meet annually to discuss mathematics education issues at all levels of learning. The aims…

  16. Canadian Mathematics Education Study Group = Groupe Canadien d'Etude en Didactique des Mathematiques. Proceedings of the Annual Meeting (25th, Edmonton, Alberta, Canada, May 25-29, 2001).

    ERIC Educational Resources Information Center

    Simmt, Elaine, Ed.; Davis, Brent, Ed.

    This document contains the proceedings of the 2001 annual meeting of the Canadian Mathematics Education Study Group (CMESG) held at the University of Alberta, May 25-39, 2000. The proceedings consist of two plenary lectures, four working groups, five topic sessions, new Ph.D. reports, an AD Hoc Session, and panel discussions. Papers include: (1)…

  17. Proceedings of the 2006 Annual Meeting of the Canadian Mathematics Education Study Group = Actes de la Rencontre Annuelle 2006 du Groupe Canadien d'Etude en Didactique des Mathematiques (30th, Calgary, Alberta, Canada, Jun 3-7, 2006)

    ERIC Educational Resources Information Center

    Liljedahl, Peter, Ed.

    2007-01-01

    This submission contains the Proceedings of the 2006 Annual Meeting of the Canadian Mathematics Education Study Group (CMESG), held at the University of Calgary in Calgary, Alberta. The CMESG is a group of mathematicians and mathematics educators who meet annually to discuss mathematics education issues at all levels of learning. The aims of the…

  18. Canadian Mathematics Education Study Group = Groupe Canadien d'etude en didactique des mathematiques. Proceedings of the Annual Meeting (23rd, St. Catherine's, ON, June 4-8, 1999).

    ERIC Educational Resources Information Center

    McLoughlin, John Grant, Ed.

    This document contains the proceedings of 1999 annual meeting of the Canadian Mathematics Education Study Group (CMESG). Papers include: (1) "Mathematics Lecture I: The Impact of Technology on the Doing of Mathematics" (Jonathan Borwein); (2) "Mathematics Lecture II: The Decline and Rise of Geometry in 20th Century North America" (Walter…

  19. Etude comparative des propriétés thermiques, électriques et optiques des verres du système argent-arsenic-sélénium

    NASA Astrophysics Data System (ADS)

    Sagbo, E.; Houphouet-Boigny, D.; Eholié, R.; Jumas, J. C.; Olivier-Fourcade, J.; Maurin, M.; Rivet, J.

    1994-11-01

    Thermal, electrical, and optical properties of glass compositions situated along the "As2Se5"-Ag2Se (region I), AsSe-Ag2Se, and AsSe-Ag (region II) lines are investigated and compared. For glass compositions of region I, the glass transition temperature (Tg) and the electrical conductivity (σ) are weak (Tg = 375 ± 5 K and σ = 2,6 × 10-7 cm-1 at 294 K for a 20% concentration of silver). For glass compositions of region II, Tg and σ are higher (Tg = 420 ± 5K and σ = 8,1 × 10-6Ω;-1cm-1 at 298 K for a 20% concentration of silver). All the glasses investigated are high-resistivity and wide-gap semiconductors since their optical gap is higher than 1.4 eV. With increasing Ag content in the glasses, Tg is almost constant, the optical gap decreases slightly but the electrical conductivity increases, and the activation energy decreases.

  20. Etude du faible poids de naissance associé à l’âge maternel et la parité dans une population couple mère-enfant suivi à Lubumbashi

    PubMed Central

    Luhete, Prosper Kakudji; Mukuku, Olivier; Kayamba, Prosper Kalenga Muenze

    2015-01-01

    Introduction Evaluer l'influence de l’âge maternel et de la parité sur la naissance d'un faible poids de naissance (FPN) à Lubumbashi. Méthodes Il s'agit d'une étude basée sur une analyse documentaire des dossiers médicaux des accouchées enregistrées dans les maternités des 10 hôpitaux généraux de référence (HGR) de la ville de Lubumbashi en République Démocratique du Congo entre le 1er décembre 2013 et le 31 mars 2014. Ces accouchées ont été réparties en deux groupes, en fonction du poids de naissance de leurs enfants: groupe I (femmes ayant accouché de nouveau-nés vivants dont le poids était inférieur à 2500 grammes) et groupe II (femmes ayant accouché de nouveau-nés vivants dont le poids était supérieur ou égal à 2500 grammes). Il s'agissait dans tous les cas de grossesses monofoetales âgées de 28 semaines ou plus. L’âge maternel et la parité ont été étudiés et comparés dans les deux groupes. Les données ont été analysées à l'aide des logiciels Épi info version 7.0 et SPSS version 19. Les différences étaient jugées significatives pour un seuil p < 0,05. Résultats La prévalence du FPN chez les nouveau-nés issus de ces accouchées était ainsi de 6,4% (71/1112). En analyse univariée, les femmes d’âge < 20 ans présentent un risque multiplié par 2,47 fois d'avoir un nouveau-né de FPN comparativement à celles de ≥20 ans (OR = 2,47; IC95%: 1,26-4,78) et celui pour les primipares d'avoir un enfant de FPN est 2,3 fois supérieur à celui de multipares (OR = 2,32; IC95%: 1,34-3,99). En faisant la régression logistique, nous avons observé que seule la parité est significativement corrélée au poids de naissance (OR ajusté = 2,61; IC95%: 1,43-4,74). Conclusion L’étude que nous avons menée montre que le taux de FPN diminue considérablement avec l’âge de la mère à partir de 20 ans et la multiparité. PMID:26161169

  1. Proceedings of the 2005 Annual Meeting of the Canadian Mathematics Education Study Group = Actes de la Rencontre Annuelle 2005 du Groupe Canadien d'Etude en Didactique des Mathematiques (29th, Ottawa, Ontario, Canada, May 27-31, 2005)

    ERIC Educational Resources Information Center

    Liljedahl, Peter, Ed.

    2006-01-01

    This submission contains the Proceedings of the 2005 Annual Meeting of the Canadian Mathematics Education Study Group (CMESG), held at the University of Ottawa in Ottawa, Ontario. The CMESG is a group of mathematicians and mathematics educators who meet annually to discuss mathematics education issues at all levels of learning. The aims of the…

  2. Etude de la Recharge de l’Accumulateur Plomb-Acide Red Camel Entre +20 C et -30 C (A Study of the Rechargeability of the Red Camel Lead-Acid Battery between +20 C and -30 C).

    DTIC Science & Technology

    1983-10-01

    Pour un voltage limite imposg de 14.3 V et une dur~e de charge de 7 heures, les rendements en courant (Rc) et en gnergie fi1ectrique (Re), calcul~s en...pour le d~marrage des v~hicules A moteur . Cependant en dega de -20*C, on assiste A une diminution importante des performances en dicharge rapide...rficup~ration de la capaciti dana le calcul des rendements en courant et en finergie filectrique. CONDUITE DES ESSAIS Lors de toul lea easais, le courant

  3. Methode de calcul a N-corps basee sur la G0W0: Etude du couplage electron-phonon dans le C60 et developpement d'une approche acceleree pour materiaux organiques

    NASA Astrophysics Data System (ADS)

    Laflamme Janssen, Jonathan

    This thesis studies the limitations of density functional theory. These limits are explored in the context of a traditional implementation using a plane waves basis set. First, we investigate the limit of the size of the systems that can be treated. Cutting edge methods that assess these limitations are then used to simulate nanoscale systems. More specifically, the grafting of bromophenyl molecules on the sidewall of carbon nanotubes is studied with these methods, as a better understanding of this procedure could have substantial impact on the electronic industry. Second, the limitations of the precision of density functional theory are explored. We begin with a quantitative study of the uncertainty of this method for the case of electron-phonon coupling calculations and find it to be substantially higher than what is widely presumed in the literature. The uncertainty on electronphonon coupling calculations is then explored within the G0W0 method, which is found to be a substantially more precise alternative. However, this method has the drawback of being severely limitated in the size of systems that can be computed. In the following, theoretical solutions to overcome these limitations are developed and presented. The increased performance and precision of the resulting implementation opens new possibilities for the study and design of materials, such as superconductors, polymers for organic photovoltaics and semiconductors. Keywords: Condensed matter physics, ab initio calculations, density functional theory, nanotechnology, carbon nanotubes, many-body perturbation theory, G0W0 method..

  4. Clinical, biologic, and pathologic features in 157 patients with angioimmunoblastic T-cell lymphoma treated within the Groupe d'Etude des Lymphomes de l'Adulte (GELA) trials.

    PubMed

    Mourad, Nathalie; Mounier, Nicolas; Brière, Josette; Raffoux, Emmanuel; Delmer, Alain; Feller, Alfred; Meijer, Chris J L M; Emile, Jean-François; Bouabdallah, Réda; Bosly, André; Diebold, Jacques; Haioun, Corinne; Coiffier, Bertrand; Gisselbrecht, Christian; Gaulard, Philippe

    2008-05-01

    To evaluate the prognostic significance of clinicobiologic and pathological features in angioimmunoblastic T-cell lymphoma (AITL), 157 AITL patients were retrieved from the GELA LNH87-LNH93 randomized clinical trials. One hundred forty-seven patients received a cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP)-like regimen with intensified courses in half of them. Histologically, 41 cases were classified as "rich in large cells" and 116 as "classic" (including 19 rich in epithelioid cells, 14 rich in clear cells, and 4 with hyperplastic germinal centers). Sixty-two cases were scored for CD10 and CXCL13 expression according to the abundance of positive lymphoid cells. Median age was 62 years, with 81% advanced stage, 72% B symptoms, 65% anemia, 50% hypergammaglobulinemia, and 66% elevated LDH. Overall 7-year survival was 30%. In multivariate analysis, only male sex (P = .004), mediastinal lymphadenopathy (P = .041), and anemia (P = .042) adversely affected overall survival. Increase in large cells and high level of CD10 and CXCL13 did not affect survival. Intensive regimen did not improve survival. In conclusion, AITL is a morphologically heterogeneous T-cell lymphoma commonly expressing CXCL13 and CD10 and carrying few prognostic factors. It portends a poor prognosis even when treated intensively. However, AITL is not always lethal with 30% of patients alive at 7 years.

  5. EDUCAFRICA, December 1986. Special Issue: Case Studies on Higher Education in Africa. Special Volume 1=EDUCAFRICA, Decembre 1986. Etudes de cas sur L'Enseignement Superieur en Afrique, Tome 1.

    ERIC Educational Resources Information Center

    EDUCAFRICA, 1986

    1986-01-01

    Case studies of the development of higher education in 17 African countries are presented. Eleven of the case studies are written in French, and six are in English. The country reports that are in English are as follows: Cameroon, Ethiopia, Lesotho, Malawi, Sierra Leone, and Tanzania. The country reports in French are: Benin, Burkina Faso,…

  6. Fate of a volatile chlorinated solvent in indoor aquatic microcosms: sublethal and static exposure to [14C]dichloromethane. Groupe pour l'Etude du Devenir de Xénobiotiques dans l'Environnement (GEDEXE).

    PubMed

    Thiébaud, H; Merlin, G; Capovilla, M P; Blake, G

    1994-06-01

    The goal of this work was to study the fate of dichloromethane in indoor aquatic microcosms after a sublethal and static exposure to simulate the accidental contamination of a lenitic ecosystem such as littoral lake zone or a pond. This kind of ecosystem is characterized by high productive capacity and rich biocoenose, and are usually first affected by acute or chronic pollution. Microcosms containing immersed bryophytes (Fontinalis antipyretica), macrophytes (Lemna minor, Groenlendia densa, Elodea canadensis), molluscs (Physa fontinalis), crustaceans (Daphnia magna), and unicellular green algae (Scenedesmus subspicatus) were contaminated with sublethal concentrations of dichloromethane or [14C]dichloromethane. The initial mean concentration was 9.9 +/- 3.7 microM. The mean concentration exposure for organisms was 4.5 +/- 1.5 microM. The fate of 14C radioactivity was monitored by measuring the radioactivity of the sediment, water, macro- and microorganism, and atmospheric compartments. Radioactivity in the water disappeared quickly from the microcosms, most likely as [14C]dichloromethane (t1/2 = 5.31 +/- 0.41 days). At the end of the experiments, radioactivity was mainly located in the atmosphere, with traces remaining in the biomass. Under static conditions, the bioaccumulation of 14C radioactivity from the radiolabeled dichloromethane was negligible.

  7. Les sous-prefectures de Sikensi et Dabakala, Cote-d'Ivoire. (The Regions of Sikensi and Dabakala, Ivory Coast.) Method de preparation de la carte scolaire: etudes de cas 9.

    ERIC Educational Resources Information Center

    Hallak, J.; And Others

    This volume contains the results of the first study of the problems associated with using educational television in curriculum planning in the Ivory Coast. The study was conducted in two districts of this African country, one relatively developed and situated in the southern part of the country, and the other more characteristic of the poorer…

  8. Etude des transitions de phases dans les systèmes K 3MO 3F 3- A3MO 3F 3( A= Na, Rb; M= Mo, W)

    NASA Astrophysics Data System (ADS)

    Fouad, M.; Chaminade, J. P.; Ravez, J.; Sadel, A.

    1996-06-01

    RésuméX-ray diffraction, differential thermal analysis, polarized light microscopy, and dielectric measurements have been used to study phase transitions and solid solutions in the K3MO3F3-A3MO3F3(A= Rb, Na;M= Mo, W) systems. K3MO3F3-Na3MO3F3(M= Mo, W) systems show two solid solutions; the first (SSI) nearx= 0 (K3-xNaxMO3F3) involves only one transition atTCwhich is practically independent of composition. The sharp transition atT1(

  9. Proceedings of the 2004 Annual Meeting of the Canadian Mathematics Education Study Group = Actes de la Rencontre Annuelle 2004 du Groupe Canadien d'Etude en Didactique des Mathematiques (28th, Quebec City, Quebec, Canada, May 28-Jun 1, 2004)

    ERIC Educational Resources Information Center

    Simmt, Elaine, Ed.; Davis, Brent, Ed.

    2005-01-01

    This submission contains the Proceedings of the 2004 Annual Meeting of the Canadian Mathematics Education Study Group (CMESG), held at Universite Laval in Quebec City, Quebec. The CMESG is a group of mathematicians and mathematics educators who meet annually to discuss mathematics education issues at all levels of learning. The aims of the Study…

  10. Etude de l'anémie chez les enfants séropositifs au VIH naïfs au traitement antirétroviral à Lubumbashi, République Démocratique du Congo

    PubMed Central

    Mwadianvita, Costa Kazadi; Ilunga, Eric Kasamba; Djouma, Jackson; Wembonyama, Cecile Watu; Mutomb, Florence Mujing A; Ekwalanga, Michel Balaka; Kabongo, Joe; Mundongo, Henri; Mupoya, Kalombo; Wembonyama, Stanis; Kalenga Mwenze, Prosper; Nkoy, Albert Mwembo-Tambwe A

    2014-01-01

    Introduction Beaucoup d'enfants infectés par le VIH arrivent à la consultation dans un état d'anémie. Notre objectif était d’évaluer la prévalence et le typage de l'anémie chez ces enfants. Méthodes C'est une étude transversale réalisée dans 3 centres de prise en charge des Personnes Vivant avec le VIH à Lubumbashi de Mai 2010 à Mai 2011. La population d’étude était de 152 enfants, âgés de 6 à 180 mois, naïfs au traitement antirétroviral. Les statistiques descriptives usuelles ont été utilisées. Résultats La prévalence globale de l'anémie (définie comme l'hémoglobine < 11g/dl) était de 69,1% (n=105) et 11,4% avaient une anémie sévère (Hg < 7,0 g/dl). Parmi eux, 16% ont été transfusés au moins 1 fois. L'anémie sévère était positivement associée au stade clinique de la maladie (p=0,02). L'anémie microcytaire était majoritaire dans les deux tranches d’âge. Elle était plus hypochrome chez les enfants en âge préscolaire soit 9,5% et plus normochrome en âge scolaire soit 15,2%. L'anémie normocytaire était plus normochrome dans les deux tranches d’âge soit 12,4% en âge préscolaire et 6,7% en âge scolaire. L'anémie macrocytaire était rare. Conclusion Environ sept enfants sur dix, âgés de moins de 15 ans infectés par le VIH naïfs au traitement antirétroviral dans notre milieu sont anémiques. L'anémie est corrélée à la sévérité de la maladie. Il est important d'associer une prise en charge nutritionnelle et corriger l'anémie avant une trithérapie antirétrovirale. PMID:25018796

  11. Re-formulation and Validation of Cloud Microphysics Schemes

    NASA Astrophysics Data System (ADS)

    Wang, J.; Georgakakos, K. P.

    2007-12-01

    The research focuses on improving quantitative precipitation forecasts by removing significant uncertainties in current cloud microphysics schemes embedded in models such as WRF and MM5 and cloud-resolving models such as GCE. Reformulation of several production terms in these microphysics schemes was found necessary. When estimating four graupel production terms involved in the accretion between rain, snow and graupel, current microphysics schemes assumes that all raindrops and snow particles are falling at their appropriate mass-weighted mean terminal velocities and thus analytic solutions are able to be found for these production terms. Initial analysis and tests showed that these approximate analytic solutions give significant and systematic overestimates of these terms, and, thus, become one of major error sources of the graupel overproduction and associated extreme radar reflectivity in simulations. These results are corroborated by several reports. For example, the analytic solution overestimates the graupel production by collisions between raindrops and snow by up to 230%. The structure of "pure" snow (not rimed) and "pure graupel" (completely rimed) in current microphysics schemes excludes intermediate forms between "pure" snow and "pure" graupel and thus becomes a significant reason of graupel overproduction in hydrometeor simulations. In addition, the generation of the same density graupel by both the freezing of supercooled water and the riming of snow may cause underestimation of graupel production by freezing. A parameterization scheme of the riming degree of snow is proposed and then a dynamic fallspeed-diameter relationship and density- diameter relationship of rimed snow is assigned to graupel based on the diagnosed riming degree. To test if these new treatments can improve quantitative precipitation forecast, the Hurricane Katrina and a severe winter snowfall event in the Sierra Nevada Range are selected as case studies. A series of control

  12. Evaluation of Mixed-Phase Microphysics Within Winter Storms Using Field Data and In Situ Observations

    NASA Technical Reports Server (NTRS)

    Colle, Brian A.; Molthan, Andrew; Yu, Ruyi; Nesbitt, Steven

    2014-01-01

    Snow prediction within models is sensitive to the snow densities, habits, and degree of riming within the BMPs. Improving these BMPs is a crucial step toward improving both weather forecasting and climate predictions. Several microphysical schemes in the Weather Research and Forecasting (WRF) model down to 1.33-km grid spacing are evaluated using aircraft, radar, and ground in situ data from the Global Precipitation Mission Cold-season Precipitation Experiment (GCPEx) experiment over southern Ontario, as well as a few years (12 winter storms) of surface measurements of riming, crystal habit, snow density, and radar measurements at Stony Brook, NY (SBNY on north shore of Long Island) during the 2009-2012 winter seasons. Surface microphysical measurements at SBNY were taken every 15 to 30 minutes using a stereo microscope and camera, and snow depth and snow density were also recorded. During these storms, a vertically-pointing Ku band radar was used to observe the vertical evolution of reflectivity and Doppler vertical velocities. The GCPex presentation will focus on verification using aircraft spirals through warm frontal snow band event on 18 February 2012. All the BMPs realistically simulated the structure of the band and the vertical distribution of snow/ice aloft, except the SBU-YLIN overpredicted slightly and Thompson (THOM) underpredicted somewhat. The Morrison (MORR) scheme produced the best slope size distribution for snow, while the Stony Brook (SBU) underpredicted and the THOM slightly overpredicted. Those schemes that have the slope intercept a function of temperature (SBU and WSM6) tended to perform better for that parameter than others, especially the fixed intercept in Goddard. Overall, the spread among BMPs was smaller than in other studies, likely because there was limited riming with the band. For the 15 cases at SBNY, which include moderate and heavy riming events, the non-spherical snow assumption (THOM and SBU-YLIN) simulated a more realistic

  13. Transfert radiatif entre une petite particule et un diélectrique: application au chauffage local

    NASA Astrophysics Data System (ADS)

    Mulet, J.-P.; Joulain, K.; Carminati, R.; Greffet, J. J.

    2002-06-01

    nous montrons dans cette étude que le transfert radiatif entre une particule de taille nanométrique et un diélectrique petit être très important lorsque les distances mises en jeu sont petites devant la longueur d'onde caractéristique du rayonnement thermique. Ce transfert peut devenir dominant lorsque les matériaux utilisés sont polaires. Nous discuterons de la possibilité d'appliquer ces résultats au chauffage local dans les nano-structures.

  14. A Mechanistic Understanding of North American Monsoon and Microphysical Properties of Ice Particles

    NASA Astrophysics Data System (ADS)

    Erfani, Ehsan

    A mechanistic understanding of the North American Monsoon (NAM) is suggested by incorporating local- and synoptic-scale processes. The local-scale mechanism describes the effect sea surface temperature (SST) in Gulf of California (GC) and how it contributes to the low-level moisture during the 2004 NAM. Before NAM onset, the strong low-level temperature inversion exists over the GC, but this inversion weakens with increasing GC SST and generally disappears once SSTs exceed 29.5°C, allowing the moist air, trapped in the MBL, to mix with free tropospheric air. This leads to a deep, moist layer that can be transported toward the NAM regions to produce thunderstorms. The synoptic scale mechanism is based on climatologies from 1983 to 2010 and explains that the warmest SSTs moving up the coast contributes to NAM convection and atmospheric heating, and consequently advancing the position of the anticyclone and the region of descent northward. In order to improve microphysical properties of ice clouds, this study develops self-consistent second order polynomial mass- and projected area-dimension (m-D and A-D) expressions that are valid over a much larger size range, compared to traditional power laws. Such expressions can easily be reduced to power laws for the size range of interest, in order to use in cloud and climate models. This was done by combining field measurements of individual ice particle m and D with airborne optical probe measurements of D, A and estimates of m. The resulting m-D and A-D expressions are functions of temperature and cloud type (synoptic vs. anvil), and are in good agreement with m-D power laws developed from recent field studies. These expressions also appear representative for heavily rimed dendrites occurring over the Sierra Nevada Mountains. By using the m-D field measurements of rimed and unrimed particles, and by developing theoretical methods, an approach was suggested for calculating rimed m and A, which has the benefit of accounting

  15. Dopamine Transporter Imaging Assessment of Parkinson’s Disease Progression

    DTIC Science & Technology

    2001-08-01

    terminal integrity, will provide a quantitative biomarker of Parkinson’s disease progression in subjects with early Parkinson’s disease during a rime...dopa on the rate of progression of Parkinson’s disease . All subjects have been and will be recruited and clinically evaluated through their participation...in early Parkinson’s disease , whether the rate of neuronal degeneration is affected by L-dopa, a potential neurotoxin, and whether the changes in

  16. A preliminary study on ice shape tracing with a laser light sheet

    NASA Technical Reports Server (NTRS)

    Mercer, Carolyn R.; Vargas, Mario; Oldenburg, John R.

    1993-01-01

    Preliminary work towards the development of an automated method of measuring the shape of ice forming on an airfoil during wind tunnel tests has been completed. A thin sheet of light illuminated the front surfaces of rime, glaze, and mixed ice shapes and a solid-state camera recorded images of each. A maximum intensity algorithm extracted the profiles of the ice shapes and the results were compared to hand tracings. Very good general agreement was found in each case.

  17. Numerical simulation of precipitation formation in the case orographically induced convective cloud: Comparison of the results of bin and bulk microphysical schemes

    NASA Astrophysics Data System (ADS)

    Sarkadi, N.; Geresdi, I.; Thompson, G.

    2016-11-01

    In this study, results of bulk and bin microphysical schemes are compared in the case of idealized simulations of pre-frontal orographic clouds with enhanced embedded convection. The description graupel formation by intensive riming of snowflakes was improved compared to prior versions of each scheme. Two methods of graupel melting coincident with collisions with water drops were considered: (1) all simulated melting and collected water drops increase the amount of melted water on the surface of graupel particles with no shedding permitted; (2) also no shedding permitted due to melting, but the collision with the water drops can induce shedding from the surface of the graupel particles. The results of the numerical experiments show: (i) The bin schemes generate graupel particles more efficiently by riming than the bulk scheme does; the intense riming of snowflakes was the most dominant process for the graupel formation. (ii) The collision-induced shedding significantly affects the evolution of the size distribution of graupel particles and water drops below the melting level. (iii) The three microphysical schemes gave similar values for the domain integrated surface precipitation, but the patterns reveal meaningful differences. (iv) Sensitivity tests using the bulk scheme show that the depth of the melting layer is sensitive to the description of the terminal velocity of the melting snow. (v) Comparisons against Convair-580 flight measurements suggest that the bin schemes simulate well the evolution of the pristine ice particles and liquid drops, while some inaccuracy can occur in the description of snowflakes riming. (vi) The bin scheme with collision-induced shedding reproduced well the quantitative characteristics of the observed bright band.

  18. The Right Stuff and the Fast Track: A Look at Soviet Military Districts and Their Commanders, 1945-1981

    DTIC Science & Technology

    1981-01-01

    i . .’ • •• " • • "i,!’•• • ,• ,, •:• •• ’’...•~ • Baranovichi Minek Grodno Molodechno Brest Polotsk Pinsk Vitebsk Baranovichi Miusk Mogilev...Polotsk Pinsk Vitebsk. Baranovichi Minsk Bobruysc Mogilev Mozyr’ Gomel’ 64 I . This arrangement lasted only a short rime, for in February 1946, the two

  19. Levels of Phonology Related to Reading and Writing in Middle Childhood

    ERIC Educational Resources Information Center

    Del Campo, Roxana; Buchanan, William R.; Abbott, Robert D.; Berninger, Virginia W.

    2015-01-01

    The relationships of different levels of phonological processing (sounds in heard and spoken words for whole words, syllables, phonemes, and rimes) to multi-leveled functional reading or writing systems were studied. Participants in this cross-sectional study were students in fourth-grade (n = 119, mean age 116.5 months) and sixth-grade (n = 105,…

  20. Long-term monitoring of local stress changes in 67km installed OPGW cable using BOTDA

    NASA Astrophysics Data System (ADS)

    Zou, L.; Sezerman, O.

    2015-09-01

    The initial results from continuing long-term monitoring of a 67 km of an aerial fiber optic cable installed on a 500 kV power line cable (total fiber length of 134km) using BOTDA are presented. The effects of thunderstorms and rime ice on the cable were identified by monitoring strain on OPGW fibers. Variations of strain between day and night on the OPGW cable were observed and can potentially be exploited.

  1. Sampling of Atmospheric Precipitation and Deposits for Analysis of Atmospheric Pollution

    PubMed Central

    Skarżyńska, K.; Polkowska, Ż; Namieśnik, J.

    2006-01-01

    This paper reviews techniques and equipment for collecting precipitation samples from the atmosphere (fog and cloud water) and from atmospheric deposits (dew, hoarfrost, and rime) that are suitable for the evaluation of atmospheric pollution. It discusses the storage and preparation of samples for analysis and also presents bibliographic information on the concentration ranges of inorganic and organic compounds in the precipitation and atmospheric deposit samples. PMID:17671615

  2. Introducing Rhode Island's Health Equity Zones.

    PubMed

    Patriarca, Mia; Ausura, Christopher J

    2016-11-01

    Many social and environmental factors contribute to the health - and unhealthiness - of a community, and the mix of these factors varies widely from one community to another. A persistent challenge to public health is just how to address so many variables, in so many combinations, in so many diverse communities. The Rhode Island Department of Health is exploring an innovative approach, its Health Equity Zone Initiative, to meet this challenge. [Full article available at http://rimed.org/rimedicaljournal-2016-11.asp].

  3. Polarimetric radar and aircraft observations of saggy bright bands during MC3E

    NASA Astrophysics Data System (ADS)

    Kumjian, Matthew R.; Mishra, Subashree; Giangrande, Scott E.; Toto, Tami; Ryzhkov, Alexander V.; Bansemer, Aaron

    2016-04-01

    Polarimetric radar observations increasingly are used to understand cloud microphysical processes, which is critical for improving their representation in cloud and climate models. In particular, there has been recent focus on improving representations of ice collection processes (e.g., aggregation and riming), as these influence precipitation rate, heating profiles, and ultimately cloud life cycles. However, distinguishing these processes using conventional polarimetric radar observations is difficult, as they produce similar fingerprints. This necessitates improved analysis techniques and integration of complementary data sources. The Midlatitude Continental Convective Clouds Experiment (MC3E) provided such an opportunity. Quasi-vertical profiles of polarimetric radar variables in two MC3E stratiform precipitation events reveal episodic melting layer sagging. Integrated analyses using scanning and vertically pointing radar and aircraft measurements reveal that saggy bright band signatures are produced when denser, faster-falling, more isometric hydrometeors (relative to adjacent times) descend into the melting layer. In one case, strong circumstantial evidence for riming is found during bright band sagging times. A bin microphysical melting layer model successfully reproduces many aspects of the signature, supporting the observational analysis. If found to be a reliable indicator of riming, saggy bright bands could be a proxy for the presence of supercooled liquid water in stratiform precipitation, which may provide important information for mitigating aircraft icing risks and for constraining microphysical models.

  4. In situ observations of snow particle size distributions over a cold frontal rainband within an extratropical cyclone

    NASA Astrophysics Data System (ADS)

    Yang, Jiefan; Lei, Hengchi

    2016-02-01

    Cloud microphysical properties of a mixed phase cloud generated by a typical extratropical cyclone in the Tongliao area, Inner Mongolia on 3 May 2014, are analyzed primarily using in situ flight observation data. This study is mainly focused on ice crystal concentration, supercooled cloud water content, and vertical distributions of fit parameters of snow particle size distributions (PSDs). The results showed several discrepancies of microphysical properties obtained during two penetrations. During penetration within precipitating cloud, the maximum ice particle concentration, liquid water content, and ice water content were increased by a factor of 2-3 compared with their counterpart obtained during penetration of a nonprecipitating cloud. The heavy rimed and irregular ice crystals obtained by 2D imagery probe as well as vertical distributions of fitting parameters within precipitating cloud show that the ice particles grow during falling via riming and aggregation process, whereas the lightly rimed and pristine ice particles as well as fitting parameters within non-precipitating cloud indicate the domination of sublimation process. During the two cloud penetrations, the PSDs were generally better represented by gamma distributions than the exponential form in terms of the determining coefficient ( R 2). The correlations between parameters of exponential /gamma form within two penetrations showed no obvious differences compared with previous studies.

  5. Acoustic and perceptual correlates of syllable weight

    NASA Astrophysics Data System (ADS)

    Gordon, Matthew; Jany, Carmen; Nash, Carlos

    2005-09-01

    Differences between languages in the stress-attracting properties of various syllable types (syllable weight) are associated with phonetic differences. Certain languages that preferentially stress CVC syllables (i.e., treat CVC as heavy) fail to display substantial vowel shortening in CVC, unlike languages that treat CVC as non-stress-attracting or light [Broselow et al. (1997)]. Furthermore, CVC has greater energy (intensity integrated over time) in languages in which it is heavy relative to languages with light CVC [Gordon (2002)]. This paper compares multiple potential acoustic and perceptual correlates of syllable weight. A representative cross section of syllable types in words uttered by speakers of four languages was recorded. In two languages (Arabic, Hindi), CVC is heavy; in two languages (Mongolian, Malayalam), CVC is light. Three measurements were taken: duration of the syllable rime, acoustic intensity integrated over the rime, and a measure of perceptual energy of the rime incorporating various factors (e.g., temporal integration and adaptation, bandpass filtering). Results thus far indicate that a measure of prominence factoring in both intensity and duration better distinguishes languages on the basis of weight criterion than a simple measure of duration. The perceptual energy measure provides a slightly better fit than acoustic energy. [Work supported by NSF.

  6. Problemes en enseignement fonctionnel des langues (Problems in the Functional Teaching of Languages). Publication B-103.

    ERIC Educational Resources Information Center

    Alvarez, Gerardo, Ed.; Huot, Diane, Ed.

    Articles include: (1) "L'elaboration du materiel pedagogique pour des publics adultes" (The Elaboration of Teaching Materials for the Adult Public) by G. Painchaud-Leblanc, (2) "L'elaboration d'un programme d'etudes en francais langue seconde a partir des donnees recentes en didactique des langues" (The Elaboration of a Program…

  7. Cultural Diversity in Mathematics (Education): CIEAEM 51.

    ERIC Educational Resources Information Center

    Ahmed, Afzal; Williams, Honor; Kraemer, Jean Marie

    The 51st meeting of the Commission Internationale pour L'Etude et L'Amelioration de L'Ensignment des Mathematiques (CIEAEM) was held July, 1999 at Chichester, UK and facilitated the collaboration of delegates from over 30 countries providing a variety of perspectives on the theme OCultural Diversity in Mathematics Education'. The papers in this…

  8. Bibliography of Books and Published Reports on Gas Turbines, Jet Propulsion, and Rocket Power Plants, January 1950 through December 1953

    DTIC Science & Technology

    1953-12-01

    compresseurs avlaux. Gauthier-Villars, Paris. P. Chambadal, Thermodynamique de la turbine A gaz. Hermann et Cie, Paris. C. H. Chatfield, CA F. Taylor, and S...NACA Tech. Note No. 2713 (June). J. Jarry, Analyse des etudes thermodynamiques . Technique et Science Adronaut. No. 6, 348. J. R. Ketchum and R. T

  9. Special Course on Aerothermodynamics of Hypersonic Vehicles

    DTIC Science & Technology

    1989-06-01

    Etude des propriftis thermodynamiques et de transport dans le plasmas thermiques A l’lquilibre et hors d’iquilibre thermodynamiques : Applications aut...Tannehill J.G. Marvin A new PNS Code for Chemical NonequitibriumFlows AIAA Paper 87- 0284 [931 S. Pn.franel Propriftisa thermodynamique . et de transport

  10. The Physics and Chemistry of carbides, Nitrides and Borides. Volume 185

    DTIC Science & Technology

    1990-01-01

    the transition metal carbides", pp. 181-190 in "Propri6t6s Thermodynamiques , Physiques et Structurales des Ddrives Semi-m6talliques", Colloque...fuse des neutrons aux dtudes de thermodynamique des alliages’, Technical Report n11/1221M, ONERA, Chatillon, France. 29. Priem, T. (1988) ’Etude de

  11. Domestic Determinants and Security Policy-Making in East Asia

    DTIC Science & Technology

    2000-11-01

    recognize that there has been no significant “peace dividend ” following the end of the Cold War and the paper enumerates the negative factors, which I am...Soviet and East-European Studies Institut d’Etudes politiques de Paris. She specializes in Russian military and strategic affairs. Yasuhiro Matsuda

  12. Survey of European Studies on the Far Field Characteristics of a Source Oscillating and Translating Near a Free Surface.

    DTIC Science & Technology

    1988-03-16

    1980. 2. Grekas, A., "Contribution i I’ Etude Theorique et Expdrimentale des Efforts du Second Ordre et du Comportement Dynamique d’une Structure Marine...47, pp. 455-479, 1948. 7. Brard, R., " Vagues engendrdes par une source pulsatoire en movement horizontal rectiligne uni- forme. Application au

  13. Teaching Beginning Trombone Players.

    ERIC Educational Resources Information Center

    Fallis, Todd L.

    2001-01-01

    Discusses the process of introducing the trombone to beginning students and addresses the issue of warming-up. Provides resources for beginning trombone methods, band methods, and daily warm-up studies. Includes resources for scale studies and etudes for beginning to intermediate trombone players. (CMK)

  14. Language of Information Science: Convertibility in Information Science

    DTIC Science & Technology

    The report is the result of a study of the language of information science based on the terminology contained in a collected set of lexical resources...Groupe d’Etude sur l’Information Scientifique’, selected because it represents an international concensus of the domain of information science . A

  15. Foreign-Language Pedagogy: Practical Applications to Theoretical Concerns. Selected Papers from the Loyola College Conference Entitled "Bridging Theory and Practice in the Foreign-Language Classroom" (Baltimore, Maryland, October 18-20, 1991).

    ERIC Educational Resources Information Center

    Wieczorek, Joseph A., Ed.

    1993-01-01

    Papers from the conference include the following: "Activites orales et motivation dans l'etude du vocabulaire d'une langue etrangere (Oral Activities and Motivation in the Study of Vocabulary in a Foreign Language)" (M. Guisset); "Bridging High School and College Classes through the Multicultural Approach: The Case of Francophone…

  16. Pedagogy of Notation: Learning Styles Using a Constructivist, Second-Language Acquisition Approach to Dance Notation Pedagogy

    ERIC Educational Resources Information Center

    Heiland, Teresa L.

    2015-01-01

    Four undergraduate dance majors learned Motif Notation and Labanotation using a second-language acquisition, playful, constructivist approach to learning notation literacy in order to learn and dance the "Parsons Etude." Qualitative outcomes were gathered from student journals and pre- and post-tests that assessed for levels of improved…

  17. EXPLOMET 90 International Conference on Shock-Wave and High-Strain-Rate Phenomena in Materials

    DTIC Science & Technology

    1992-01-10

    Kottke, Ballistic Research Laboratory, Aberdeen Proving Ground, MD 8. SHOCK SYNTHESIS AND REACTION-ASSISTED CONSOLIDATION OF SILICIDES LL. Yu and M. A...FRANCE L.4/expOI/L EXPLOMET - 90 27 11. DYNAMIC BEHAVIOUR OF BERYLLIUM D. Montoya, G. Nauiin, J. P. Ansart, Centre d’Etudes de Bruyeres Le Chatel

  18. New technology to realize printed radiating elements

    NASA Astrophysics Data System (ADS)

    Tarot, A. C.; Sharaiha, A.; Terret, C.; Garnier, Y.

    1995-05-01

    A plating process for low-cost dielectric substrates (like polypropylene or foam) has been developed by the CNET (Centre National d'Etudes des Telecommunications) in collaboration with LAM (Laboratoire Antennes et Microelectronique). This process allows the realization of printed radiating elements like microstrip antennas. An example of a multilayered printed antenna realized with this technology is presented with its performance.

  19. User Needs and Major Challenges for Defence Against Terrorism - Results of SeNTRE Study for European Commission Preparatory Action on Security Research

    DTIC Science & Technology

    2006-05-01

    l’Armement (Centre d’Etude du Bouchet), FhG (Fraunhofer-Gesellschaft), VTT (VTT Technical Research Centre of Finland), EADS Astrium , Finmeccanica...Technical Research FhG Allemagne Centre of Finland VTT Finlande EADS EADS France EADS Astrium ASM-U UK Finmeccanica FNM Italie Dassault DASS France

  20. Micromechanical Behavior of Frictional Geologic Materials

    DTIC Science & Technology

    1988-11-01

    ranging from a suspension of particles to multicontacted particles forming a material with continuous force-deformation characteristics, i.e., a...Vol. 14, No. 4, pp. 25-38 (1974). 15. Biarez, J., "Contribution a l’Etude des Proprietes Mecaniques des Sols et des Materiaux Pulverulents," These de

  1. The Flight of Flexible Aircraft in Turbulence - State-of-the-Art in the Description and Modelling of Atmospheric Turbulence: Meeting of the Structures and Materials Panel of AGARD (64th) Held in Athens (Greece) on 28 September-3 October 1986

    DTIC Science & Technology

    1987-12-01

    Flights. Le Groupe de I’AGARD charge de I’etude des Structures et des Materiaux etudie actuellement le vol des avions flexibles dans les turbulences...D.O.F. FORCED OSC. ANGULAR OSCILLATION TRANSL. OSCILLATION SINGLE D.O.F. FREE OSC. FREE FLIGHT SEMI-FREE CONTROLLED MAGNETIC SUSPENSION

  2. The Work of Ambroise Tardieu: The First Definitive Description of Child Abuse

    ERIC Educational Resources Information Center

    Roche, A.J.; Fortin, G.; Labbe, J.; Brown, J.; Chadwick, D.

    2005-01-01

    The first important monograph describing the battered child syndrome was written in 1860 by Ambroise Tardieu, a French forensic physician. Here is a translation of his article, published in the Annales d'hygiene publique et de medecine legale, with the title ''Etude medico-legale sur les sevices et mauvais traitements exerces sur des enfants.''…

  3. A Helpful Framework for the Organization of the Homecare

    DTIC Science & Technology

    2007-11-02

    Beuscart1 1 Centre d’Etude et de Recherches en Informatique Médicale – Université de Lille2 – Faculté de Médecine – LILLE France 2 LAMIH- PERCOTEC, UVHC, Le...Recherches en Informatique Medicale Universite de Lille2- Faculte de Medecine- LILLE France Performing Organization Report Number Sponsoring/Monitoring Agency

  4. Mathematics for Vocational Students in France and England: Contrasting Provision and Consequences. Discussion Paper No. 23.

    ERIC Educational Resources Information Center

    Wolf, Alison

    French postsecondary education for 16- to 19-year-olds is divided into programs that lead to the Baccalaureats--general, technical, and vocational--and to the lower-level Certificat d'Aptitude Professionnel (CAP) and Brevet d'Etudes Professionnelles (BEP). A common mathematics core curriculum is specified for all CAP students, regardless of…

  5. Closed-Cycle Rare-Gas Electrical-Discharge Laser

    DTIC Science & Technology

    1977-04-01

    Shtyrkov and E. V. Subbes, "Characteristics of Pulsed Laser Action in Helium-Neon and Helium-Argon Mixtures," Optics and Spectroscopy 21, 143 (August 1966...34Etude du Deplacement des Raies Laser Infrarouges du Xenon sous l’Influence de la Pression," Phys. Lett. 33A, 398 (November 1970). 89. L. A. Newman

  6. Mathematical Discovery: Hadamard Resurected

    ERIC Educational Resources Information Center

    Liljedahl, Peter

    2004-01-01

    In 1943 Jacques Hadamard gave a series of lectures on mathematical invention at the Ecole Libre des Hautes Etudes in New York City. These talks were subsequently published as The Psychology of Mathematical Invention in the Mathematical Field (Hadamard, 1945). In this article I present a study that mirrors the work of Hadamard. Results both…

  7. European Conference on Advanced Materials and Processes Held in Aachen, Federal Republic of Germany on November 22-24, 1989

    DTIC Science & Technology

    1989-11-24

    d’Etudes Nuclhaires de Grenoble (France) Molecular Beam Epitaxy of HgCdTe Compounds Discussion 14.45 A. J. Oster, IBM Deutschland, Sindelfingen (FRG) IBM...Concentration in Eiectrolytlc Aluminium Cells Xi. 8 F. Castro (Sp), 1. ltumrza, J. Echebemra, Centro de Estudios e lnvestigaciones Tecnicas de Guipuzcoa

  8. Initial Evaluation of Advanced Powder Metallurgy Magnesium Alloys for Armor Development

    DTIC Science & Technology

    2009-05-01

    wettability with magnesium, e.g., titanium particles, will be considered in the future work. 11 5. References 1. Jones, T. L.; DeLorme, R. D...28911 LEGANES MADRID SPAIN 1 CELIUS MATERIAL TEKNIK KARLSKOGA AB L HELLNER S 69180 KARLSKOGA SWEDEN 3 CENTRE D’ETUDES GRAMAT

  9. Bibliographie (Bibliography).

    ERIC Educational Resources Information Center

    Francais dans le Monde, 1981

    1981-01-01

    Presents a selective bibliography of dictionaries, books, and articles. References are grouped under three sections: I. Lexicology, II. Dictionaries and III. Didactics. Each item is followed by a concise critical note. The compilation is by the "Centre d'Etudes du Lexique" (CELEX, Paris-Villetaneuse). (MES)

  10. An Arabic-English-French Lexicon of the Dialects Spoken in the Chad-Sudan Area, 1. [Lexique des parlers arabes tchado-soudanais, 1.

    ERIC Educational Resources Information Center

    Roth-Laly, Arlette, Comp.

    This lexicon, a preliminary publication of a project dealing with Arabic dialects in the Chad-Sudan area, has been compiled from four earlier lexicons: G. Trenga, "Le bura-maband du Ouadai"; H. Carbou, "Methode pratique pour l'etude de l'arabe parle au Ouaday et a l'Est du Tchad"; G.L. Lethem, "Colloquial Arabic, Shua…

  11. The Role of the Department of State in the Foreign Policy Decision-Making Process

    DTIC Science & Technology

    1987-02-01

    traveled in Western Europe, Morocco, India and Pakistan. In addition to her degree programs, she has studied at the Sorbonne and the Ecole des Etudes...of the geog1"aphic buz-eaus. At present, the Foreign Service regards the idea. of greater Civil Service input into pol icy as heret icai , and the

  12. Storage Ring Technology for Free Electron Lasers.

    DTIC Science & Technology

    1984-04-01

    Because of this it was easy to lose all of 20 ..... %"€ the stored beam by accidently exciting the strongly coupled tune while seeking the weaker tune...calculation also applies to was supported by the DRET, the Centre d’Etudes Nucleaires de high-pover input laser beams (a0 > 1) provided one Saclay DPC SPP SP

  13. The Shock and Vibration Digest. Volume 13, Number 4

    DTIC Science & Technology

    1981-04-01

    proper con- tainment as necessary, as well as developing tech- niques to reduce incidence of accidents during normal plant and transport operations...d’Etudes Nucleaires de Saclay, 91190-Git-sur- Yvette, France, Computers Struc, 12 (4), pp 471- 474 (Oct 1980) 3figs, 12refs 44 Key Words

  14. The Normative Effects of Higher Education Policy in France

    ERIC Educational Resources Information Center

    Langan, Elise

    2012-01-01

    This student survey was a response to the French youth unrest in 2005 and 2006. It considers the degree to which French higher and secondary education institutions create social cohesion. Focusing on three distinct higher-education institutions: "L'institut d'etudes politiques de Paris" (Sciences Po), "Ecole Normale…

  15. The Improvement of Brass Instrument Teaching Through the Use of a Profile of the Physical Aspects Involved. Final Report.

    ERIC Educational Resources Information Center

    Nichols, Russell L.; And Others

    To aid in providing a sounder methodological program in the teaching of trumpet playing, a study was made of the profiles of physical parameters involved in playing the instrument. Data were collected while beginning, intermediate, or advanced players performed scales in F, D, and B-flat and two etudes in both staccato and legato. The means used…

  16. The French Language in the Americas.

    ERIC Educational Resources Information Center

    Valdman, Albert, Ed.

    The annual bulletin of the French 8 section of the Annual Meeting of the Modern Language Association of America is presented with the texts of papers read at both the 1969 and 1970 sessions. The 1970 papers, in French, include Jean Louis Darbelnet's "Etude Sociolinguistique des contacts entre 1'Anglais et le Francais au Canada et en…

  17. JPRS Report, Soviet Union, Peoples of Asia & Africa, No. 5, September-October 1987

    DTIC Science & Technology

    1988-04-01

    to contribute to this aim. JAPAN: "FAIR INCOME DISTRIBUTION" V.B. Ramzes The author makes a determined effort to critically analyse one of the...internatio- nale. Notes et Etudes documentaires . La documenta- tions francaise. Paris, 1984, pp 15-18. The data cited give only an approximate

  18. Operational Research Support to the Army Sustainability Exercise

    DTIC Science & Technology

    2001-11-01

    presente le processus de l’ESA, les donnees generees pour appuyer !’analyse et les resultats de l’etude. P517047.PDF [Page: 7 of 173] Executive Summary...MAINTIEN EN PUISSANCE • Dectsons - 1993 Etablissement -1997 Plan d’urgence - 2000 Recrutement - 2001 Balance P517047.PDF [Page: 91 of 173

  19. Centenary Birth Anniversary of E. W. Beth (1908-1964)

    ERIC Educational Resources Information Center

    Bagni, Giorgio T.

    2008-01-01

    Evert Willem Beth (1908-1964) was a Dutch logician, mathematician and philosopher, whose work mainly concerned the foundations of mathematics. Beth was among the founders of the Commission Internationale pour l'Etude et l'Amelioration de l'Enseignement des Mathematiques and was a member of the Central Committee of the International Commission on…

  20. NbN Josephson and Tunnel Junctions for Space THz Observation and Signal Processing

    DTIC Science & Technology

    2005-07-13

    jonctions Josephson en nitrures supraconducteurs (TiN et NbN) ; application à la logique RSFQ, Ph.D. thesis, SPSMS/LCP CEA - Grenoble and DEMIRM...Accepted for Publication in June 2005. [14] V. Larrey, Etude et réalisation de jonctions SIS à base de nitrure de niobium et d’une barrière tunnel

  1. Caractérisation spectrale et temporelle de l'émission X issue de l'interaction laser-agrégats

    NASA Astrophysics Data System (ADS)

    Bonté, C.; Fourment, C.; Harmand, M.; Jouin, H.; Micheau, S.; Peyrusse, O.; Pons, B.; Santos, J. J.

    2006-12-01

    Les agrégats de gaz rares constituent un état de la matière intermédiaire entre les cibles solides massives et les atomes en phase gazeuse. Il a été démontré que les agrégats irradiés sont sources d'ions, d'électrons, de neutrons ainsi que de rayonnement allant du visible aux X durs. Cette source peut-être produite avec un taux de répétition élevé et a l'avantage de ne pas produire de débris, dommageables pour les optiques notamment, et de présenter une très forte conversion de l'énergie laser incidente. Nous nous intéressons au rayonnement X particulièrement, en le caractérisant en intensité, spectre et durée, comme préalable à toute application de cette source X et comme moyen privilégié d'étude de la physique des plasmas nanométriques chauds et denses. En collaboration avec l'INRS-Énergie (Varenne, Qc, Canada), nous avons mis en œuvre une caméra à balayage de fente dont la résolution temporelle est de 800 fs rms. En focalisant des impulsions laser courtes (30 fs 5 ps) et intenses (jusqu'à 1017 W/cm2) sur des agrégats d'argon dont le rayon varie de 15 à 30 nm, nous avons démontré que l'émission X dont l'énergie est supérieure à 2 keV est plus courte que 2 ps, limité par la résolution temporelle. En couplant la caméra à un cristal tronconique, dont la conception a été réalisée au LULI (Palaiseau, France), nous nous sommes intéressés au rayonnement de couche K dans la gamme 2,9 - 3,2 keV. Nous avons démontré que ce rayonnement a une durée inférieure à 3 ps (limite de la résolution temporelle), et que les raies étaient émises avec un écart relatif inférieur à 1 ps. Une simulation basée sur le modèle nano-plasma proposé par T. Ditmire et sur le code collisionnel-radiatif Transpec a été développée au CELIA. Les spectres X résolus en temps calculés reproduisent à la fois la brièveté d'émission du rayonnement X et les états de charge élevés observés.

  2. Etude de la flore bactérienne contaminant les téléphones mobiles avant et après la désinfection: comparaison entre les professionnels soignants de l'hôpital militaire d'instruction Mohammed V de Rabat et les témoins

    PubMed Central

    Uwingabiye, Jean; Moustanfii, Wafaa; Chadli, Meryem; Sekhsokh, Yassine

    2015-01-01

    Introduction L'objectif de notre travail était évaluer la contamination microbienne des téléphones mobiles utilisés par les personnels soignants des différents services de l'hôpital militaire d'instructions Mohammed V de Rabat et la comparer à celui d'une population témoin et aussi démontrer l'efficacité des solutions hydroalcoolique dans la désinfection de ces téléphones mobiles. Méthodes Il s'agit d'une étude descriptive transversale réalisée sur une période de 9 mois entre septembre 2010 et juin 2011, dans le service de bactériologie de l'hôpital militaire d'Instruction Mohammed V. Résultats L’étude bactériologique a été faite sur 240 téléphones mobiles dont 50% provenaient de personnels de sante. Le taux de contamination bactérienne de tous les téléphones mobiles était de 100%. Les cultures des bactéries isolées au niveau des téléphones mobiles du personnel médical étaient plus polymorphes que celles de la population témoin (p=0,028). Parmi 437 bactéries isolées: 223(51%) provenaient de téléphones de personnels de santé et 214(49%) de téléphones de la population témoin avec une différence qui n’était pas statistiquement significative(p>0,05) sauf pour les isolats de Staphylocoque à coagulase négative et Staphylococcus aureus. Les bactéries isolées étaient représentées par: Staphylocoque à coagulase (57,7%), Staphylococcus aureus (18,1%), Corynebacterium sp (18,8%), Bacillus sp (2,3%) et autres (2,2%). La différence entre la prévalence des bactéries isolées selon les services et les fonctions des personnels de santé n’était pas statistiquement significative (p>0,05). La désinfection des téléphones portables par la solution hydroalcoolique a réduit à 99,5% le nombre des colonies. Conclusion Ce travail montre que les téléphones portables pourraient jouer un rôle dans la transmission des infections nosocomiales et communautaires. Dans le cadre de prévention de ces risques, il faut sensibiliser les utilisateurs des téléphones mobiles l'importance du lavage des mains et l'utilisation des solutions hydro alcoolique pour désinfecter aussi bien les téléphones portables que les mains. PMID:26977234

  3. Etudes diélectriques de la transition ferroélectrique induite par application d'un champ électrique dans les céramiques PbMg{1/3}Nb{2/3}O3 (PMN)

    NASA Astrophysics Data System (ADS)

    Chabin, M.; Malki, M.; Husson, E.; Morell, A.

    1994-07-01

    The evolution of the dielectric permittivity and loss factor under an external applied electric field has been studied in PbMg{1/3}Nb{2/3}O3 ceramics between 80 and 420 K. For a threshold field of 4 kV.cm^{-1}, it is possible to induce a ferroelectric transition from the average cubic phase to a macroscopically polar phase. The poling and depoling temperatures depend on the various combinations of thermal treatments and on the applied field strength. The transition between the nanopolar state and the macropolar state is discussed L'évolution de la permittivité diélectrique et du facteur de pertes diélectriques sous un champ électrique extérieur a été étudiée dans des céramiques de PbMg{1/3}Nb{2/3}O3 enre 80 et 420 K. Pour un champ de seuil de 4 kV.cm^{-1} il est possible d'induire une transition ferroélectrique de la phase cubique moyenne en une phase macroscopiquement polaire. Les températures de polarisation et de dépolarisation dépendent des différentes combinaisons de traitements thermiques et de la valeur du champ appliqué. La transition entre la phase constituée de nanodomaines polaires et la phase constituée de macrodomaines polaires est discutée.

  4. Standard chemotherapy with interferon compared with CHOP followed by high-dose therapy with autologous stem cell transplantation in untreated patients with advanced follicular lymphoma: the GELF-94 randomized study from the Groupe d'Etude des Lymphomes de l'Adulte (GELA).

    PubMed

    Sebban, Catherine; Mounier, Nicolas; Brousse, Nicole; Belanger, Coralie; Brice, Pauline; Haioun, Corinne; Tilly, Herve; Feugier, Pierre; Bouabdallah, Redah; Doyen, Chantal; Salles, Gilles; Coiffier, Bertrand

    2006-10-15

    The purpose of this study is to compare our standard chemotherapy regimen (CHVP [cyclophosphamide, doxorubicin, teniposide, and prednisone]) plus interferon with 4 courses of CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone) followed by high-dose therapy with autologous stem cell transplantation (ASCT) in treatment-naive patients with advanced follicular lymphoma. Four hundred one patients were included from July 1994 to March 2001: 209 received 12 cycles of CHVP plus interferon alpha for 18 months (CHVP-I arm) and 192 received 4 cycles of CHOP followed by high-dose therapy (HDT) with total body irradiation and ASCT (CHOP-HDT arm). Overall response rates were similar in both groups (79% and 78% after induction chemotherapy, respectively). One hundred thirty-one of the 150 patients eligible for HDT underwent transplantation (87%). Intent-to-treat analysis after a median follow-up of 7.5 years showed that there was no difference between the 2 arms for overall survival (P = .53) or event-free survival (P = .11). Patients with a complete response at the end of the induction therapy had a statistically longer event-free survival and overall survival (P = .02 and < .001, respectively). After long-term follow-up, our study showed that there was no statistically significant benefit in favor of first-line high-dose therapy in patients with follicular lymphoma. High-dose therapy should be reserved for relapsing patients.

  5. Expression of the granzyme B inhibitor PI9 predicts outcome in nasal NK/T-cell lymphoma: results of a Western series of 48 patients treated with first-line polychemotherapy within the Groupe d'Etude des Lymphomes de l'Adulte (GELA) trials.

    PubMed

    Bossard, Céline; Belhadj, Karim; Reyes, Felix; Martin-Garcia, Nadine; Berger, Françoise; Kummer, Jean Alain; Brière, Josette; Baglin, Anne-Catherine; Cheze, Stéphane; Bosq, Jacques; Ribrag, Vincent; Gisselbrecht, Christian; Mounier, Nicolas; Gaulard, Philippe

    2007-03-01

    Nasal NK/T-cell lymphoma is a rare disease entity with a poor outcome. Expression of antiapoptotic proteins has not been extensively investigated in this entity. Forty-eight patients with nasal T/NK-cell lymphoma who received first-line polychemotherapy (n = 44) or chemoradiotherapy (n = 4) were analyzed for expression of active caspase-3 (aC3), granzyme B protease inhibitor 9 (PI9), and Bcl-2 proteins. Lymphomas were CD3+/CD5-/granzyme B+ and EBV-associated. Median age was 46 years. Stage I/II disease was present in 75% of the cases and an International Prognostic Index (IPI) score less than 1 in 65%. With a median follow-up of 6.3 years, 5-year event-free survival (EFS) and overall survival (OS) rates were 39% and 49%, respectively. Apoptotic index was scored as high in 32% of cases and PI9 expression as positive in 68%, whereas 35% disclosed a high number of aC3+ tumor cells. Univariate analysis showed that absence of PI9 and low apoptotic index were associated with poor outcome, but not aC3 expression nor IPI score. By multivariate analysis, both parameters affected independently EFS (P = .02 and .08, respectively) and OS (P = .009 and .04). In view of its constitutive expression by normal NK cells, it is suggested that loss of PI9 expression in tumor cells may reflect some mechanism associated with progression.

  6. L'interdisciplinarite en sciences sociales pour l'etude du contact des langues (Interdisciplinarity in Social Sciences of the Study of the Relationships of Languages). Proceedings of a Colloquium of the International Center for Research on Bilingualism and the Institute for Interethnic and Intercultural Studies and Research (2nd, Quebec City, Quebec, Canada, October 1-5, 1984).

    ERIC Educational Resources Information Center

    Prujiner, Alain, Ed.

    Papers given at an international conference applying the social sciences to the study of the relationships of languages include the following: "Reseaux sociaux et comportements langagiers en milieu de contact des langues" ("Social Networks and Language Behaviors in a Language Contact Setting") by M. Blanc and J. Hamers, with…

  7. The Training of Modern Language Teachers in Various Countries. Collection d'"Etudes linguistiques," No. 20. Selected papers from the Association Internationale pour la Recherche et la Diffusion des Methodes Audio-Visuelles et Structuro-Globales Seminar (5th, August 27-September 1, 1973).

    ERIC Educational Resources Information Center

    Nivette, Jos, Ed.

    Selected papers that address theoretical and practical training of the modern language teacher and language teaching experiments in various countries are presented. Some of the articles included are the following: "Les problemes de la formation linguistique et pedagogique des professeurs de francais en Afrique Subsaharienne" (The…

  8. Contribution to the G0 violation of parity experience: calculation and simulation of radiative corrections and the background noise study; Contribution a l'experience G0 de violation de la parite : calcul et simulation des corrections radiatives et etude du bruit de fond

    SciTech Connect

    Guler, Hayg

    2003-12-17

    In the framework of quantum chromodynamics, the nucleon is made of three valence quarks surrpounded by a sea of gluons and quark-antiquark pairs. Only the only lightest quarks (u, d and s) contribute significantly to the nucleon properties. In Go we using the property of weak interaction to violate parity symmetry, in order to determine separately the contributions of the three types of quarks to nucleon form factors. The experiment, which takes place at Thomas Jefferson laboratory (USA), aims at measuring parity violation asymmetry in electron-proton scattering. By doing several measurements at different momentum squared of the exchanged photons and for different kinematics (forward angle when the proton is detected and backward angle it will be the electron) will permit to determine separately strange quarks electric and magnetic contributions to nucleon form factors. To extract an asymmetry with small errors, it is necessary to correct all the beam parameters, and to have high enough counting rates in detectors. A special electronics was developed to treat information coming from 16 scintillator pairs for each of the 8 sectors of the Go spectrometer. A complete calculation of radiative corrections has been clone and Monte Carlo simulations with the GEANT program has permitted to determine the shape of the experimental spectra including inelastic background. This work will allow to do a comparison between experimental data and theoretical calculations based on the Standard Model.

  9. Etude du profil d'echelle des formes et de mesures d'energie de texture pour l'evaluation semi-automatique des degâts sur les bâtiments dans les images satellitaires de tres haute resolution

    NASA Astrophysics Data System (ADS)

    Dubois, David

    Dozens of natural disasters occur each year throughout the world. They cause the death of thousands of people and cost billions of dollars in losses and reconstruction. Considerable resources are invested in the various phases of the emergency cycle like response and reconstruction. To avoid mismanagement of human and material resources during the response to a disaster, decisions must be made very quickly. To make appropriate choices, decision makers need up to date information on conditions on the ground. The images acquired by satellite are a possible source for this information. The new satellites equipped with optical sensors having spatial resolution finer than a meter per pixel provide details useful for determining the status of roads and damage to buildings. Unfortunately, visual analysis of these very large images is time consuming and fatigue may increase the rate of human error. In this thesis, we propose a semi-automatic method for the extraction of buildings and damage assessment using geometric, radiometric and texture features. The work includes a review of the literature in order to identify gaps in current approaches and possible solutions, the development of a methodology to solve this difficult problem, the testing of the proposed method on a portion of images of the city of Port-au-Prince, Haiti captured before and after the earthquake of January 12, 2010, assessment of results and their comparison with the literature. The proposed method requires processing of the image in a hierarchical tree shapes through the fast level set transform. Once the image is represented in this way, an algorithm for extracting meaningful forms is used to assign a representative form for each pixel. Geometrical descriptors such as area, perimeter and others from central moments are extracted from these forms. In addition, for damage assessment, energy measurements of texture are calculated on the forms before and after the event. Buildings are extracted using a supervised classifier based on a support vector machine (SVM). The damage is classified according to three degrees: little or no damage, damaged and destroyed. After experiment, the proposed method for the evaluation of damage exceeds those proposed in the recent literature both in rapidity and accuracy. The use of the scale profile and Laws textures are considerable innovations in the field of remote sensing brought by this thesis.

  10. Etude expérimentale de la fixation de métaux par un matériau sédimentaire actuel d'origine algaire - I. Isolement, purification et caractérisation de la matière organique

    NASA Astrophysics Data System (ADS)

    Disnar, J.-R.; Trichet, J.

    1981-03-01

    In order to study the 'in vitro' fixation of metal ion species on algal and bacterial sedimentary organic matter, two algal mat samples have been studied. The main interest of this organic matter is its specific cyanobacterial origin. After isolation and purification, the organic matter was characterized by elemental and functional analysis, infrared spectroscopy. carbohydrates and amino-acid titration. These analyses indicate the richness of this type of organic matter in amino acids and carbohydrates, its poverty in aromatic structures, and to ascertain the types of bacteriological and chemical transformations undergone by the original biological compounds in the first steps of the diagenesis.

  11. Etudes sur le système ternaire SnInS. Analyses thermique differentielle et radiocristallographique du pseudobinaire SnSIn 2S 3. Croissance en phase vapeur et caractérisation de composés a valences mixtes de l'étain

    NASA Astrophysics Data System (ADS)

    Adenis, Claire; Olivier-Fourcade, Josette; Jumas, Jean-Claude; Philippot, Etienne

    1986-11-01

    The SnInS ternary system has been studied using two different methods of crystal synthesis. By direct combination of the two sulfides (SnS and In 2S 3) various melts have been prepared, and the ternary phase diagram determined by differential thermal analysis. Three ternary phase are found: In 2Sn 2S 5, In 2SnS 4, and In 12Sn 5S 23. Chemical vapor transport (CVT), using iodine as transport gas, leads to different crystal morphologies (needles, sheets, and polyhedra) according the ratio of iodine to reagent. Several methods have been used to characterize the crystals, specifically X-ray diffraction, electronic microscopy, and Mössbauer spectrometry. The latter shows that both Sn(II) and Sn(IV) are present in all the crystals prepared by CVT.

  12. Etude de l'effet de la température de dépôt ou de recuit sur la formation de l'interface Au/GaSb(100) par diffraction d'électrons lents et spectroscopies d'électrons Auger ou de pertes d'énergies

    NASA Astrophysics Data System (ADS)

    Rouanet, M.; Oueini, W.; Nouaoura, M.; Bertru, N.; Bonnet, J.; Lassabatere, L.

    1995-05-01

    Auger electron spectroscopy (AES), energy electron loss spectroscopy (EELS) and low energy electron diffraction (LEED) are used to precise the interaction of gold with GaSb(100) surfaces grown on GaSb substrates by molecular beam epitaxy (MBE). After the growth, the GaSb layers, produced in the laboratory, were transferred by the mean of an ultra vacuum lock chamber, into an other ultra vacuum devoted to the deposit of gold and to the physical studies. Measurements were first performed on the clean surfaces and then on surfaces covered by increasing amounts of gold (6 × 10^{13} 1.8 × 10^{16} atoms cm^{-2}) deposited on substrates brought at room temperature or at low temperature (220 K). The samples were then studied during the annealing up to 520 K. The results show, at the beginning of the deposition, gold was adsorbed on the MBE GaSb(100) surface. When the gold coverage increases and becomes higher than 10^{15} atomes cm^{-2}, Au diffuses into the bulk and forms alloys. Nous étudions par spectroscopie d'électrons Auger (SEA), spectroscopie de pertes d'énergies d'électrons lents (SPEEL) et diffraction d'électrons lents (DEL), l'adsorption de l'or sur des surfaces (100) de couches de GaSb obtenues au laboratoire par épitaxie par jets moléculaires (EJM) sur des substrats de GaSb, puis transférées pour dépôt et étude dans l'enceinte à ultravvide de dépôt métallique par l'intermédiaire d'un sas sous ultravide. Les mesures sont effectuées avant et après dépôts d'or (6 × 10^{13} 1,8 × 10^{16} atomes cm^{-2}) réalisés sur un substrat à la température ambiante ou refroidi à 220 K. Les échantillons sont ensuite étudiés pendant lerecuit jusqu'à 520 K. Les résultats obtenues montrent que l'or, dans un premier temps s'adsorbe sur la surface, puis, lorsque le dépôt augmente, diffuse dans le volume du matériau. cette diffusion, qui peut s'acompagner de la formation d'alliages, n'est cependant notable dans la gamme de température utilisée que pour des dépôts supérieurs à 10^{15} atomes cm^{-2}.

  13. Some Implications of Linguistic Theory for Applied Linguistics. Collection d'"Etudes linguistiques," No. 19. Papers from the Neuchatel Colloquium in Applied Linguistics in collaboration with AIMAV, AILA, CILA, and the University of Neuchatel (3rd, May 30-June 1, 1974).

    ERIC Educational Resources Information Center

    Corder, S. P., Ed.; Roulet, E., Ed.

    Papers that address implications of linguistic theory for applied linguistics are presented. In "Some Semantic Properties of Some Conjunctions," W. Abraham is concerned with the function of "but" and its translation equivalents in German and other languages. In "Is It Possible and Necessary to Write Text Grammars?," T. P. Krzeszowski examines the…

  14. Etude structurale des sulfotellurures de terres rares ( LS) 2Te 1+ x ( L = Tb, Dy, Ho, Er, Tm et Y). I. Sous-structure de la phase ordonnée de (HoS) 2Te 1,34. Structure de la phase desordonnée de (TbS) 2Te

    NASA Astrophysics Data System (ADS)

    Ghémard, G.; Etienne, J.; Flahaut, J.

    1982-11-01

    The lanthanide sulfotellurides ( LS) 2Te 1+ x (0 ≤ x < 0.50) show order-disorder phenomena. Above 450°C, they crystallize in a partially disordered structure, orthorhombic with cell parameters a, b, and c close to 4.1, 5.2, and 13.6 Å, respectively. This structure is determined from diffractometer data on a (HoS) 2Te 1.34 crystal ( R = 0.061). It is built up along the c axis from ( L4S) tetrahedra layers, separated by Te planes. Disorder and nonstoichiometry are related to the two vacant Te sites.

  15. The history of three scientific societies: the Society for the Study of Fertility (now the Society for Reproduction and Fertility) (Britain), the Société Française pour l'Etude de la Fertilité, and the Society for the Study of Reproduction (USA).

    PubMed

    Clarke, John

    2007-06-01

    Three scientific societies devoted to the study of reproduction were established in Britain, France and USA in the middle of the twentieth century by clinical, veterinary and agricultural scientists. The principal motivation for their establishment had been the study of sterility and fertility of people and livestock. There was also a wider perspective embracing other biologists interested in reproduction more generally. Knowledge disseminated through the societies' scientific meetings and publications would bear upon human and animal population problems as well as basic reproductive physiology and its applications. New journals dealing with reproductive physiology, having worldwide appeal, were established in Britain and USA. The financial resources of at least one of the societies and its journal are directed towards charitable functions, including financial support for travel to scientific meetings, for visits to particular laboratories, and for research in the short term, including that of undergraduates. Perhaps the example of the British society has given rise to others having a more specialised focus, as well as to the formation of the European Society for the Study of Human Reproduction and Embryology.

  16. Etude des facteurs liés à l'observance au traitement antirétroviral chez les patients suivis à l'Unité de Prise En Charge du VIH/SIDA de l'Hôpital de District de Dschang, Cameroun

    PubMed Central

    Mbopi-Kéou, François-Xavier; Dempouo Djomassi, Lucienne; Monebenimp, Francisca

    2012-01-01

    Introduction Etudier les facteurs liés à l'observance au traitement antirétroviral chez les patients adultes suivis à l'Unité de Prise en Charge du VIH/SIDA (UPEC) de l'hôpital de District de Dschang. Méthodes Dans une étude descriptive transversale conduite à l'hôpital de District de Dschang, l'observance a été évaluée sur la base des déclarations des patients et sur la régularité du renouvellement de leurs ordonnances (observance calculée). Résultats Parmi les 389 patients répondant à nos critères d'inclusion, 356 ont été interrogés. La durée moyenne du suivi était de 27 mois. La moyenne d’âge était égale à 41 ans et le sexe ratio 2,46 en faveur du sexe féminin. Le statut sérologique était découvert pour 60,56% des patients à l'occasion d'un épisode maladif. Le niveau d'observance déclarée était significativement plus élevé que le niveau global de l'observance calculée (80,2% vs 51,5%, p<10−5). Les deux principales barrières à l'observance étaient l'oubli et le travail. Les patients référés dans cette UPEC étaient moins bien observants (p<10−4). L'observance au traitement antirétroviral était d'autant meilleure quand le taux de CD4 en début de traitement était élevé (p= 0,01) et que la durée du traitement était prolongée (p=0,00). Conclusion La discordance observée entre les résultats des deux méthodes utilisées pour estimer l'observance, tout en soulévant les contraintes liées à l’évaluation de l'observance thérapeutique, souligne l'importance des méthodes biologiques. Les facteurs individuels se sont avérés être les principales raisons de non-observance. Enfin, un accent devrait être mis sur les consultations d’éducation thérapeutique et le suivi psycho-social des patients sous traitement antirétroviral dans cette UPEC. PMID:22937195

  17. The Effects of Strong Shock Waves on Mortality Rates and Percentages of Pulmonary Lesions in Rats as a Function of the Number of Exposures (Etude des effets des ondes de choc fortes sur les taux de letalite et les pourcente ages de lesions pulmoneires chea le rat en fonotior du nombre d’expositions)

    DTIC Science & Technology

    1978-12-01

    This study of pulmonary lesions and mortality rates caused in rats by exposure to strong shock waves of constant duration revealed that with regard... mortality rates , it revealed that halving the overpressure of the wave crest is offset by a 20-fold increase in the number of exposures.

  18. Attitudes Sociales et Intellectuelles et Valeurs a Developper dans L'Enseignement Quebecois des Sciences Humaines au Primaire: Une Analyse des Propositions du Programme D'Etudes (Social and Intellectual Attitudes and Values to Be Developed in Social Science Instruction in the Elementary Grades in Quebec: An Analysis of the Proposals of the Program of Study).

    ERIC Educational Resources Information Center

    Laforest, Mario; Lenoir, Yves

    1994-01-01

    Discusses Quebec's elementary school social studies program, which aims to promote the development of politically correct social attitudes and scientifically correct intellectual attitudes. Suggests that, under the cover of a developmental approach to "savoir-etre" ("knowing how to be"), the program supports a technobehaviorist…

  19. Etudes structurales de composés de type cémentite: Effet de l'hydroge`ne sur Fe 3C suivi par diffraction neutronique. Spectrométrie Mössbauer sur FeCo 2B et Co 3B dopés au 57Fe

    NASA Astrophysics Data System (ADS)

    Fruchart, D.; Chaudouet, P.; Fruchart, R.; Rouault, A.; Senateur, J. P.

    1984-02-01

    Accurate neutron diffractograms obtained using Fe 3C powdered samples have been recorded using position sensitive detectors. The structure parameters have been determined in the 20-650°C range both in vacuo and in hydrogen atmosphere. No significant location of hydrogen atoms in the cell could be detected before the complete decomposition of Fe 3C, which is considerably enhanced by H 2 gas and is accompanied by an initial loss of carbon (<5%). The magnetic diffraction peaks correspond to ferromagnetic moments directed along the yaxis: M(4 c) ⋍ M(8f) = 1.8 ± 0.1 μ B(extrapolated). Such a value agrees reasonably well with those obtained from Mössbauer data. Comparison with the isomorphous borides or Fe-substitutedCo 3X compounds indicates that a rigid band model is inadequate to describe the electronic scheme of Fe in cementite and related compounds. Analysis of the stability of M3Xcementite-type structured materials reveals the major role of M(d)-X(p) hybridization.

  20. Le cours d'anglais de l'Ecole des Hautes Etudes Commerciales de Lausanne est devenu un cours pluridisciplinaire (The English Course in the School for Higher Business Studies in Lausanne Has Become a Multidisciplinary Course). Acts of the Colloquium of the Swiss Interuniversity Commission for Applied Linguistics. CILA Bulletin, No. 25.

    ERIC Educational Resources Information Center

    Vaucher, Marius

    From the beginning, a major preoccupation of the business English course described here has been to respond to students' needs concerning programs of study as well as their future professional needs. Accordingly, these principles basic to all teaching procedures were adopted: (1) the material being learned must be put into practice; (2) such…