Showing papers by "Conservatoire national des arts et métiers published in 2004"

Gigacycle fatigue in mechanical practice

Abstract: Written by pioneers in the study and analysis of very high cycle fatigue, Gigacycle Fatigue in Mechancal Practice compiles the most recent findings on gigacycle fatigue phenomena, focusing on improving the reliability and performance of key engine and machine components. This reference reflects the explosion of new concepts, testing methods, and data on very high cycle fatigue and collects the latest analytical methods and results from renowned authorities on the subject. The authors showcase recently developed technologies for improving performance and preventing fatigue in long-life cars, aircraft engines, high-speed trains, commercial power generators, and ships.

Energy-dense diets are associated with lower diet costs: a community study of French adults

Abstract: Objective: High consumption of energy-dense foods has been linked to high energy intakes and excess weight gain. This study tested the hypothesis that high energy density of the total diet is associated with lower diet costs. Design: Dietary intakes of 837 French adults, aged 18–76 years, were assessed using a dietary history method. Dietary energy density (MJ kg 21 ) was calculated by dividing total energy by the edible weight of foods consumed. Daily diet cost (e day 21 ) was estimated using mean national food prices for 57 food items. The relationship between dietary energy density and diet cost at each level of energy intake was examined in a regression model, adjusted for gender and age.

Lead and Mercury Sensing by Calixarene-Based Fluoroionophores Bearing Two or Four Dansyl Fluorophores

Abstract: A detailed study on the photophysical and complexing properties of calixarenes bearing two and four dansyl derivatives (Calix-DANS2 and Calix-DANS4) in a CH 3 CN/H 2 O mixture (60:40 v/v) is reported. Calix-DANS2 shows a high selectivity towards Hg 2 + over interfering cations (Na + , K + , Ca 2 + , Cu 2 + , Zn 2 + , Cd 2 + and Pb 2 + ) and a sensitivity in the 10 - 7 mol L - 1 concentration range. The complexation of mercury ion induces a strong fluorescence quenching due to a well-defined electron transfer process from the fluorophore to the metal center. Calix-DANS4 exhibits an extremely high affinity for Pb 2 + with a high selectivity over various competing ions. The unprecedented detection limit (4 μg L - 1 ) is fully compatible with the level defined by the World Health Organisation. The affinity of Calix-DANS4 for Pb 2 + can be rationalized by the activation of the inert pair of electrons on Pb 2 + . The number of fluorophores involved in the complexation can be determined from a careful time-resolved fluorescence characterization.

Subjetividade, trabalho e ação

Abstract: Este artigo traz algumas questoes para o debate sobre as relacoes entre trabalho e subjetividade. Nessa perspectiva o trabalho e aquilo que implica, do ponto de vista humano, o fato de trabalhar: gestos, saber-fazer, um engajamento do corpo, a mobilizacao da inteligencia, a capacidade de refletir, de interpretar e de reagir as situacoes; e o poder de sentir, de pensar e de inventar. O real do trabalho sempre se manifesta afetivamente para o sujeito, ai se estabelece uma relacao primordial de sofrimento, experimentada pelo sujeito, corporificada. Trabalhar e preencher a lacuna entre o prescrito e o real. Por isto e que uma parte importante do trabalho efetivo permanece na sombra, nao podendo, entao, ser avaliado. Outra questao abordada e sobre os acordos firmados entre os trabalhadores no seio do coletivo, de uma equipe ou de um oficio, que tem sempre uma vetorizacao dupla: de uma parte, um objetivo de eficacia e de qualidade do trabalho; de outra parte, um objetivo social. E proposta tambem uma discussao entre a teoria psicodinâmica do trabalhar, onde a centralidade do trabalho e um dos seus alicerces e a teoria psicanalitica onde esta questao nao e abordada diretamente.

Finite element formulation of viscoelastic sandwich beams using fractional derivative operators

Abstract: This paper presents a finite element formulation for transient dynamic analysis of sandwich beams with embedded viscoelastic material using fractional derivative constitutive equations. The sandwich configuration is composed of a viscoelastic core (based on Timoshenko theory) sandwiched between elastic faces (based on Euler– Bernoulli assumptions). The viscoelastic model used to describe the behavior of the core is a four-parameter fractional derivative model. Concerning the parameter identification, a strategy to estimate the fractional order of the time derivative and the relaxation time is outlined. Curve-fitting aspects are focused, showing a good agreement with experimental data. In order to implement the viscoelastic model into the finite element formulation, the Grunwald definition of the fractional operator is employed. To solve the equation of motion, a direct time integration method based on the implicit Newmark scheme is used. One of the particularities of the proposed algorithm lies in the storage of displacement history only, reducing considerably the numerical efforts related to the non-locality of fractional operators. After validations, numerical applications are presented in order to analyze truncation effects (fading memory phenomena) and solution convergence aspects.

Dietary intakes and food sources of n-6 and n-3 PUFA in French adult men and women.

Abstract: The intake of individual n−6 and n−3 PUFA has been estimated in 4,884 adult subjects (2,099 men and 2,785 women), volunteers from the French SU.VI.MAX intervention trial. The food intakes of each subject were recorded in at least ten 24-h record questionnaires completed over a period of 2.5 yr, allowing the estimation of the daily intake of energy; total fat; and linoleic, α-linolenic, arachidonic, eicosapentaenoic (EPA), n−3 docosapentaenoic (DPA), and docosahexaenoic (DHA) acids. The mean total fat intake corresponded to 94.1 g/d (36.3% of total energy intake) in men and 73.4 g/d (38.1% of energy) in women. The intake of linoleic acid was 10.6 g/d in men and 8.1 g/d in women, representing 4.2% of energy intake; that of α-linolenic acid was 0.94 g/d in men and 0.74 g/d in women, representing 0.37% of energy intake, with a mean linoleic/α-linolenic acid ratio of 11.3. The mean intakes of long-chain PUFA were: arachidonic acid, 204 mg/d in men and 152 mg/d in women; EPA, 150 mg/d in men and 118 mg/d in women; DPA, 75 mg/d in men and 56 mg/d in women; DHA, 273 mg/d in men and 226 mg/d in women; long-chain n−3 PUFA, 497 mg/d in men and 400 mg/d in women. Ninety-five percent of the sample consumed less than 0.5% of energy as α-linolenic acid, which is well below the current French recommendation for adults (0.8% of energy). In contrast, the mean intakes of long-chain n−6 and n−3 PUFA appear fairly high and fit the current French recommendations (total long-chain PUFA: 500 mg/d in men and 400 mg/d in women; DHA: 120 mg/d in men and 100 mg/d in women). The intakes of α-linolenic acid, and to a lesser extent of linoleic acid, were highly correlated with that of lipids. Whereas the main source of linoleic acid was vegetable oils, all food types contributed to α-linolenic acid intake, the main ones being animal products (meat, poultry, and dairy products). The main source of EPA and DHA (and of total long-chain n−3 PUFA) was fish and seafood, but the major source of DPA was meat, poultry, and eggs. Fish and seafood consumption showed very large interindividual variations, the low consumers being at risk of insufficient n−3 PUFA intake.

Consumption of Foods Rich in Flavonoids Is Related to a Decreased Cardiovascular Risk in Apparently Healthy French Women

Abstract: A high consumption of flavonoids may lower cardiovascular risk through their antioxidant capacity. This study evaluated the relation between consumption of foods rich in flavonoids and estimated cardiovascular risk. A cross-sectional analysis was performed in 1286 women and 1005 men of the SU.VI.MAX Study (an 8-y trial evaluating the effect of antioxidant supplementation on the incidence of major chronic diseases). Dietary intakes were estimated using six 24-h dietary records collected during the year between the clinical measurement of blood pressure, weight and height and the biological measurement of total serum cholesterol and fasting plasma glucose. The relation between flavonoid rich food consumption and cardiovascular risk factors was evaluated with analyses of covariance and the effect on cardiovascular risk with logistic regression analyses. In women, flavonoid-rich food consumption was inversely related to systolic blood pressure (P = 0.005). No relation between risk factors and flavonoid-rich food consumption was seen in men. Women in the highest tertile of flavonoid-rich food consumption were at lower risk for cardiovascular disease [odds ratio (OR): 0.31; 95%CI: 0.14, 0.68], whereas a positive tendency was seen in men (OR: 1.38; 95%CI: 0.96, 2.00). These results indicate that in women, a high consumption of flavonoid-rich foods may prevent cardiovascular disease.

Dietary N-6 and N-3 polyunsaturated fatty acids and prostate cancer risk: a review of epidemiological and experimental evidence.

Abstract: Objective: This study reviews epidemiological and experimental works dealing with the effects of dietary n–6 or n–3 polyunsaturated fatty acids (PUFA) on prostate cancer (PCa) development and PCa risk.

Increased poliovirus-specific intestinal antibody response coincides with promotion of Bifidobacterium longum-infantis and Bifidobacterium breve in infants: a randomized, double-blind, placebo-controlled trial.

Abstract: To determine whether the size of the intestinal bifidobacterial population can influence the immune response to poliovirus vaccination in infants, we set up a randomized, placebo-controlled trial. From birth to 4 mo, infants were given a fermented infant formula (FIF) or a standard formula (placebo). Bifidobacteria were quantified monthly in infant stools. Antipoliovirus IgA response to Pentacoq® was assessed before and 1 mo after the second vaccine injection. Thirty infants were randomized, and 20 completed the study (nine in the placebo group and 11 in the FIF group). Fecal bifidobacterial level was significantly higher with the FIF group at 4 mo of age (p = 0.0498). Furthermore, B. longum/B. infantis carriage was higher at 4 mo in the FIF group (p = 0.0399). Antipoliovirus IgA titers increased after Pentacoq® challenge (p < 0.001), and the rise was significantly higher in the FIF group (p < 0.02). Antibody titers correlated with bifidobacteria, especially with B. longum/B. infantis and B. breve levels (p < 0.002). Infants who harbored B. longum/B. infantis also exhibited higher levels of antipoliovirus IgAs (p < 0.002). In conclusion, the present results indicate that antipoliovirus response can be triggered with a fermented formula that is able to favor intestinal bifidobacteria. Whether this effect on the immune system is achieved through the bifidogenic effect of the formula (mainly through B. longum/B. infantis and B. breve stimulation) or directly linked to compounds (i.e. peptides) produced by milk fermentation remains to be investigated.

Review article: gut flora and inflammatory bowel disease.

Abstract: The pathogenesis of inflammatory bowel disease involves interactions between the host susceptibility, mucosal immunity and intestinal microflora. There is therefore great interest in the changes in the endogenous flora in inflammatory bowel disease patients and in the establishment of potential genetic variations in host responses to endogenous bacteria. In this review, we summarize the modifications in the various regional ecosystems in the gastrointestinal tract during inflammatory bowel disease (luminal bacteria in faeces or inside the gastrointestinal tract, bacteria in mucus and bacteria directly attached to the mucosa). Results were obtained following a 'candidate microorganism strategy' and, as is occurring increasingly frequently, following a 'full description strategy', which has progressed largely due to the development of culture-independent techniques. The possibility of modifying the ecosystem using prebiotics or probiotics offers hope for new treatment developments, particularly in the prevention of relapse.

The BNM Watt balance project

Abstract: A new Watt balance project is now in progress at the Bureau National de Metrologie (BNM), Paris, France. In this paper, the general configuration and the main parts of the experimental setup currently in development are presented. The aim is to contribute to the international effort in monitoring the kilogram toward a new definition of the mass unit with a relative accuracy of 10/sup -8/ or better.

L’action située dans le développement de l’activité

Abstract: Apres avoir brievement tente de rendre compte des differents courants de l’action situee et de la cognition distribuee, on examine leurs apports du point de vue des theories de l’activite, et plus particulierement des rapports entre fonctionnement et developpement de l’activite. On argumente que l’action situee en cherchant a rapatrier le sujet dans la situation, et en le reincarnant socialement, identifie une limite de la psychologie cognitive. Mais qu’en distribuant les invariants de l’action a l’exterieur du sujet, ce sont les caracteristiques de la situation qui expliquent l’activite. Ce balancier epistemologique, deja ete discute par H. Wallon, ne permet pas de rendre compte du developpement de l’activite, ni du rapport entre ce qui est donne dans la situation de travail et ce qui est cree dans la situation par les acteurs.

Determination of an efficient and reliable method for DNA extraction from ticks

Abstract: Molecular detection of pathogenic microorganisms in ticks is based on DNA amplification of the target pathogen; therefore, extraction of DNA from the tick is a major step. In this study, we compared three different tick DNA extraction protocols based on an enzymatic digestion by proteinase K followed by DNA extraction by a commercial kit (method 1), or on mortar crushing, proteinase K digestion and phenol/chloroform DNA extraction (method 2) and fine crushing with a beads beater, proteinase K digestion and DNA extraction using a commercial kit (method 3). The absence of PCR inhibitors and the DNA quality were evaluated by PCR amplification of the tick mitochondrial 16S rRNA gene using tick-specific primers. With method 1, 23/30 (77%) of the samples were extracted; with method 2, 30/31 (97%) of the samples were extracted and with method 3, 30/30 (100%) of the samples were extracted. DNA extraction efficiency using method 3 is significantly higher than DNA extraction efficiency using method 1 (100% versus 77%, P < 0.05). There was no significant difference between methods 2 and 3. Method 3 was however more adapted to cohort studies than method 2. This technique was validated for cohort tick DNA extraction and applicable to the treatment of small samples such as nymphs and soft ticks with 100% efficiency.

JAC: an aspect-based distributed dynamic framework

Abstract: In this paper, we present the Java Aspect Components (JAC) framework for building aspect-oriented distributed applications in Java. This paper describes the aspect-oriented programming model and the architectural details of the framework implementation. The framework enables extension of application semantics for handling well-separated concerns. This is achieved with a software entity called an aspect component (AC). ACs provide distributed pointcuts, dynamic wrappers and metamodel annotations. Distributed pointcuts are a key feature of our framework. They enable the definition of crosscutting structures that do not need to be located on a single host. ACs are dynamic. They can be added, removed, and controlled at runtime. This enables our framework to be used in highly dynamic environments where adaptable software is needed.

Morphological aspects of martensite–austenite constituents in intercritical and coarse grain heat affected zones of structural steels

Abstract: Thermal simulation with Gleeble was performed in order to reproduce HAZ microstructures in steels with silicon content varying between 0.003 and 0.315%. Optical metallographic characterisation of the fine scale constituents was used to investigate the formation of martensite–austenite (M–A) constituents in coarse grain heat affected zones or intercritically reheated heat affected zones. It was found that silicon increased the density of M–A constituents, the proportion of the large and massive constituents, and favoured their formation on a wider range of temperature. Compared with the coarse grain heat affected zone, a further intercritical peak increases notably the proportion of large and massive M–A constituents. Experiments showed that a subsequent temper treatment contributes to the transformation of M–A into carbides, higher silicon delaying this transformation. It was shown that the change in M–A morphology during tempering cannot be described as a progressive “shrinkage” phenomenon resulting from carbon diffusion.

Building and maintaining ontologies: a set of algorithms

Abstract: "Is_A" links are the core component of all ontologies and are organized into "hierarchies of concepts". In this paper we will first address the problem of an automatic help to build sound hierarchies. Dependencies called "existence constraints" are the foundation for the definition of a "normalized" hierarchy of concepts. In the first part of the paper algorithms are provided to obtain a normalized hierarchy starting either from concepts or from instances using Boolean functions. The second part of the paper is devoted to the hierarchy maintenance: automatically inserting, merging or removing pieces of knowledge. We also provide a way to give synthetic views of the hierarchy.

Effect of fat nature and aroma compound hydrophobicity on flavor release from complex food emulsions.

Abstract: Complex food emulsions containing either hydrogenated palm kernel oil (vegetable fat) or anhydrous milk fat (animal fat) were flavored by using different aroma compounds. The fats differed by their fatty acid and triacylglycerol compositions and by their melting behavior, while the aroma compounds (ethyl butanoate, ethyl hexanoate, methyl hexanoate, mesifurane, linalool, diacetyl, cis-3-hexen-1-ol, and gamma-octalactone) differed by their hydrophobicity. Application of differential scanning calorimetry to fat samples in bulk and emulsified forms indicated differences in the ratio of solid-to-liquid between temperatures ranging from 10 to 35 degrees C. Solid-phase microextraction coupled with GC-MS analysis indicated that flavor release from food emulsions containing animal or vegetable fat differed depending on both the fat nature and flavor compound hydrophobicity. The release of diacetyl was higher for emulsions containing animal fat, whereas the release of esters was higher for emulsions containing vegetable fat. The release of cis-3-hexenol, linalool, gamma-octalactone, and mesifurane (2,5-dimethyl-4-methoxy-(2H)-furan-3-one) was very similar for the two fatty systems. The above results were discussed not only in terms of aroma compound hydrophobicity, but also in terms of structural properties of the emulsions as affected by the lipid source.

Bloch Oscillations of Ultracold Atoms: A Tool for a Metrological Determination of h / m Rb

Abstract: We use Bloch oscillations in a horizontal moving standing wave to transfer a large number of photon recoils to atoms with a high efficiency ($99.5%$ per cycle). By measuring the photon recoil of $^{87}\mathrm{Rb}$, using velocity-selective Raman transitions to select a subrecoil velocity class and to measure the final accelerated velocity class, we have determined $h/{m}_{\mathrm{Rb}}$ with a relative precision of 0.4 ppm. To exploit the high momentum transfer efficiency of our method, we are developing a vertical standing wave setup. This will allow us to measure $h/{m}_{\mathrm{Rb}}$ better than ${10}^{\ensuremath{-}8}$ and hence the fine structure constant $\ensuremath{\alpha}$ with an uncertainty close to the most accurate value coming from the ($g\ensuremath{-}2$) determination.

Picosecond dynamics of the photoexcited 6-methoxyquinoline and 6-hydroxyquinoline molecules in solution

Abstract: The photophysical properties of 6-methoxyquinoline (6MeOQ) and 6-hydroxyquinoline (6HQ) in organic solvents and in neutral, acidic, and alkaline aqueous solutions have been studied by picosecond transient absorption spectroscopy. The dynamics of photoinduced tautomerization by excited state proton transfer(s) arising in the case of 6HQ has been analyzed. Hydroxyl deprotonation of the cationic (quinolinium) form in acidic solution (pH 1.5) is 1 order of magnitude faster (τdp ∼ 2.2 ps) than imine protonation of the anionic (phenolate) form in 1 M KOH alkaline solution (τp ∼ 30 ps). In neutral solution, our results suggest a two-step process of initial proton release from the hydroxyl group followed by proton capture by the nitrogen atom with characteristic times close to the τdp and τp values, respectively.

Personal control and coping with retail crowding

Abstract: To provide high quality services under conditions of crowding, it is important to understand the relationships between crowding and personal control. Indeed, in recent years, there has been growing belief that personal control is significant in coping with crowding. However, most studies have been of limited theoretical and practical value because they did not provide an integrated conceptualization of crowding. The results of a field study demonstrate that the personal control‐crowding relationships depend on the individual's crowding experience and the nature of personal control.

Reduced models for fluid–structure interaction problems

Abstract: Several so-called reduced order formulations are reviewed for linear vibration analysis of bounded fluid-structure systems for low modal density situations. Compressibility effects in the fluid for interior structural-acoustic problems, and free surface gravity effects, for hydroelastic-sloshing interaction problems in the case of incompressible liquids, are examined. Reduced order models leading to symmetric matrix systems are then described using the static well-posed behaviour of the irrotational fluid. In this respect, the fluid-structure boundary value local equations, expressed in terms of fluid scalar field variables for the fluid (and displacement variables for the structure) are regularized for zero-frequency limit.

Long-term SARS coronavirus excretion from patient cohort, China

Abstract: This study investigated the long-term excretion of severe acute respiratory syndrome-associated coronavirus in sputum and stool specimens from 56 infected patients. The median (range) duration of virus excretion in sputa and stools was 21 (14-52) and 27 (16-126) days, respectively. Coexisting illness or conditions were associated with longer viral excretion in stools.

The role of the state in evolutionary economics

Abstract: From an evolutionary perspective, the role of public policy extends far beyond the mere correction of market failures emphasised by neoclassical economics. Public policy may facilitate the market process. It may also guide the market process (in the case of multiple equilibria). The state can finally play a more creative role by allowing private agents to satisfy individually or collectively certain goals unattainable through market forces alone. However, this paper shows that although the scope of useful public policies is broader in an evolutionary approach than in neoclassical economics, the government's ability to direct the evolution of the economic system is highly limited. This paper also tries to formulate certain normative criteria which could act as public policy guidelines in an evolutionary perspective. Copyright 2004, Oxford University Press.

Charge and current-sensitive preamplifiers for pulse shape discrimination techniques with silicon detectors

Abstract: New charge- and current-sensitive preamplifiers coupled to silicon detectors and devoted to studies in nuclear structure and dynamics have been developed and tested. For the first time shapes of current pulses from light charged particles and carbon ions are presented. Capabilities for pulse shape discrimination techniques are demonstrated.