Showing papers by "University of Grenoble published in 2000"

Vortex Methods: Theory and Practice

Abstract: The book Vortex Methods: Theory and Practice presents a comprehensive account of the numerical technique for solving fluid flow problems. It provides a very nice balance between the theoretical development and analysis of the various techniques and their practical implementation. In fact, the presentation of the rigorous mathematical analysis of these methods instills confidence in their implementation. The book goes into some detail on the more recent developments that attempt to account for viscous effects, in particular the presence of viscous boundary layers in some flows of interest. The presentation is very readable, with most points illustrated with well-chosen examples, some quite sophisticated. It is a very worthy reference book that should appeal to a large body of readers, from those interested in the mathematical analysis of the methods to practitioners of computational fluid dynamics. The use of the book as a text is compromised by its lack of exercises for students, but it could form the basis of a graduate special topics course. Juan Lopez

Cognitive Decline Is Associated with Systemic Oxidative Stress: The EVA Study

Abstract: OBJECTIVE: To determine whether systemic oxidative stress status is associated with cognitive decline. DESIGN: A longitudinal population-based study. SETTING: A cohort study of older subjects in Nantes, France. PARTICIPANTS: A total of 1166 high cognitive functioning subjects aged 60 to 70 in the Etude du Vieillissement Arteriel (EVA) cohort with a 4 year follow-up. MEASUREMENTS: Subjects completed a baseline interview and a global cognitive test (Mini-Mental Status Examination (MMSE)). Blood samples were obtained at baseline to determine plasma levels of selenium, carotenoids, thiobarbituric acid reactant substances (TBARS), an indicator of lipoperoxidation, and red blood cell vitamin E. Risk of cognitive decline, defined as a loss of 3 points in MMSE score between baseline and the 4 year follow-up, was assessed by oxidative stress level. RESULTS: Subjects with the highest levels of TBARS show an increased risk of cognitive decline (adjusted odds ratio (OR) = 2.25; confidence interval (CI) 95% = 1.26–4.02). This result is reinforced in the lower antioxidant status subgroup. Subjects with low levels of selenium have an increased risk of cognitive decline (OR = 1.58; CI 95% = 1.08–2.31) after adjustment for various confounding factors. CONCLUSIONS: These results suggest that increased levels of oxidative stress and/or antioxidant deficiencies may pose risk factors for cognitive decline. The direct implication of oxidative stress in vascular and neurodegenerative mechanisms that lead to cognitive impairment should be further explored.

Structure of H-exchanged hexagonal birnessite and its mechanism of formation from Na-rich monoclinic buserite at low pH.

Abstract: The structural transformation of high pH Na-rich buserite (NaBu) to H-exchanged hexagonal birnessite (HBi) at low pH was studied by simulation of experimental X-ray diffraction patterns. Four HBi samples were prepared by equilibration of NaBu at constant pH in the range pH 5-2. The samples differ from each other by the presence of one (at pH 2 and 3) or two (at pH 4 and 5) phases, and by the structural heterogeneity of these phases which decreases with decreasing pH. The sample obtained at pH 5 is a 4:1 physical mixture of a 1H phase ( a = 4.940 A, b = a /√3 = 2.852 A, c = 7.235 A, β = 90°, γ = 90°) and of a 1M phase ( a = 4.940 A, b = a /√3 = 2.852 A, c = 7.235 A, β = 119.2°, γ = 90°) in which successive layers are shifted with respect to each other by + a /3 along the a axis as in chalcophanite. Both the 1H and 1M phases contain very few well-defined stacking faults at pH 5. At pH 4, the sample is a 8:5 physical mixture of a 1H phase containing 15% of monoclinic layer pairs and of a 1M phase containing 40% of orthogonal layer pairs. Any further decrease of the pH leads to the formation of a single defective 1H phase. This 1H phase contains 20% and 5% of monoclinic layer pairs at pH 3 and 2, respectively. Independent of pH, all phases contain 0.833 Mnlayer cations, 0.167 vacant layer sites, and 0.167 interlayer Mn cations located either above or below layer vacancies per octahedron. A structural formula is established at each pH. The origin of the observed phase and structural heterogeneities has been analyzed. 1H and 1M phases are assumed to inherit their specific structural and crystal chemical features from the two distinct NaBu modifications. NaBu type I, with a high proportion of Mn4+layer cations, is thought to be responsible for the monoclinic layer stacking because this configuration allows Mn cations from adjacent layers to be as far as possible from each other, thus minimizing the electrostatic repulsion between these high charge cations. In contrast, NaBu type II has a high interlayer charge induced by Mn3+layer for Mn4+layer substitutions. Consequently, the 1H phase has a high amount of interlayer protons and achieves compensation of the unfavorable overlap of layer and interlayer Mn cations, in projection on the ab -plane, by the presence of strong hydrogen bondings between layers. The higher proportion of defined stacking faults in both 1H and 1M phases at pH 4 compared to pH 5 can be attributed to the increase in reaction rate with decreasing pH. At lower pH (3 and 2) the formation of strong hydrogen bonds between adjacent layers controls the layer stacking mode and leads to the formation of a unique 1H phase. The proportion of well-defined stacking faults in this phase decreases from pH 3 to 2.

Software configuration management: a roadmap

Abstract: This paper, in the first chapter summarizes the state of the art in SCM, showing the evolution along the last 25 years. Chapter 2 shows the current issues and current research work under way in the area. In chapter 3, the challenges SCM has to take up, as well as SCM future research are discussed.

Sequence and analysis of chromosome 3 of the plant Arabidopsis thaliana.

Abstract: Arabidopsis thaliana is an important model system for plant biologists. In 1996 an international collaboration (the Arabidopsis Genome Initiative) was formed to sequence the whole genome of Arabidopsis and in 1999 the sequence of the first two chromosomes was reported. The sequence of the last three chromosomes and an analysis of the whole genome are reported in this issue. Here we present the sequence of chromosome 3, organized into four sequence segments (contigs). The two largest (13.5 and 9.2 Mb) correspond to the top (long) and the bottom (short) arms of chromosome 3, and the two small contigs are located in the genetically defined centromere. This chromosome encodes 5,220 of the roughly 25,500 predicted protein-coding genes in the genome. About 20% of the predicted proteins have significant homology to proteins in eukaryotic genomes for which the complete sequence is available, pointing to important conserved cellular functions among eukaryotes.

Ratio of triglycerides to HDL cholesterol is an indicator of LDL particle size in patients with type 2 diabetes and normal HDL cholesterol levels.

Abstract: OBJECTIVE: In patients with type 2 diabetes, a normal HDL cholesterol level does not rule out that LDL particles may be small. Although techniques for analyzing LDL subfractions are not likely to be used in clinical practice, a prediction of LDL size based on a regular lipid profile may be useful for assessment of cardiovascular risk. RESEARCH DESIGN AND METHODS: Sixty patients with type 2 diabetes with acceptable glycemic control and an HDL cholesterol level > or = 1 mmol/l were recruited after cessation of lipid-altering treatments. LDL size was determined by 2-20% PAGE; patients having small LDL (n = 30) were compared with those having intermediate or large LDL (n = 30). RESULTS: Clinical characteristics, pharmacological therapies, lifestyle, and prevalence of diabetes-related complications were similar in both patient groups. LDL size correlated negatively with plasma triglycerides (TGs) (R2 = 0.52) and positively with HDL cholesterol (R2 = 0.14). However, an inverse correlation between the TG-to-HDL cholesterol molar ratio and LDL size was even stronger (R2 = 0.59). The ratio was > 1.33 in 90% of the patients with small LDL particles (95% CI 79.3-100) and 16.5% of those with larger LDL particles. A cutoff point of 1.33 for the TG-to-HDL cholesterol ratio distinguishes between patients having small LDL values better than TG cutoff of 1.70 and 1.45 mmol/l. CONCLUSIONS: The TG-to-HDL cholesterol ratio may be related to the processes involved in LDL size pathophysiology and relevant with regard to the risk of clinical vascular disease. It may be suitable for the selection of patients needing an earlier and aggressive treatment of lipid abnormalities.

Pseudo-effective line bundles on compact K\"ahler manifolds

Abstract: The goal of this work is to pursue the study of pseudo-effective line bundles and vector bundles. Our first result is a generalization of the Hard Lefschetz theorem for cohomology with values in a pseudo-effective line bundle. The Lefschetz map is shown to be surjective when (and, in general, only when) the pseudo-effective line bundle is twisted by its multiplier ideal sheaf. This result has several geometric applications, e.g. to the study of compact Kahler manifolds with pseudo-effective canonical or anti-canonical line bundles. Another concern is to understand pseudo-effectivity in more algebraic terms. In this direction, we introduce the concept of an "almost" nef line bundle, and mean by this that the degree of the bundle is nonnegative on sufficiently generic curves. It can be shown that pseudo-effective line bundles are almost nef, and our hope is that the converse also holds true. This can be checked in some cases, e.g. for the canonical bundle of a projective 3-fold. From this, we derive some geometric properties of the Albanese map of compact Kahler 3-folds.

Precise Dental Implant Placement in Bone Using Surgical Guides in Conjunction With Medical Imaging Techniques

Abstract: The use of medical imaging techniques to make a very precise surgical guide for implant placement is described. This template is the combination of a currently used template and a very simple mechanical system designed to transfer a preoperatively defined implant position onto the surgical site. With the planning software, the practitioner determines the implant position according both to the ideal position dictated by the final restorative prosthesis and the available volume of bone. The surgical template then communicates the actual implant position to the surgical site. The template can be used not only in critical anatomical situations but also in placing the implant in an ideal position on bone because it eliminates possible manual placement errors and matches planning to prosthetic requirements.

Treatment of Primary Venous Insufficiency by Endovenous Saphenous Vein Obliteration

Abstract: The objective of this paper is to evaluate treatment of primary venous insufficiency by endovenous saphenous vein obliteration. Three hundred one limbs were treated in 206 women and 67 men with a m...

HST/NICMOS2 coronagraphic observations of the circumstellar environment of three old PMS stars: HD 100546, SAO 206462 and MWC 480

Abstract: The close environment of four old Pre-Main Sequence stars has been observed thanks to the coronagraphic mode of the HST/NICMOS2 camera at lambda=1.6 micron. In the course of this program, the detection of a circumstellar annulus around HD 141569 has already been presented in Augereau et al.(1999b). In this paper, we report the detection of an elliptical structure around the Herbig Be star HD 100546 extending from the very close edge of the coronagraphic mask (~50 AU) to 350-380 AU (3.5-3.8 arcsec) from the star. The axis ratio gives a disk inclination of 51+/-3 degrees to the line-of-sight and a position angle of 161+/-5 degrees, measured east of north. At 50 AU, the disk has a surface brightness between 10.5 and 11 mag/arcsec^2, then follows a -2.92+/-0.04 radial power law up to 250-270 AU and finally falls as r^{-5.5+/-0.2}. The inferred optical thickness suggests that the disk is at least marginally optically thick inside 80 AU and optically thin further out. Combined with anisotropic scattering properties, this could explain the shape of a brightness asymmetry observed along the minor axis of the disk. This asymmetry needs to be confirmed. The circumstellar disks around SAO 206462 and MWC 480 are not resolved, leading to constraints on the dust distribution. A tight binary system separated by only 0.32+/-0.04 arcsec is nevertheless detected in the close vicinity of SAO 206462.

Capacity of soil amendments in lowering the phytoavailability of sludge-borne zinc

Abstract: Amender le sol est une des voies possibles pour diminuer l'exposition excessive des racines des vegetaux aux metaux comme le zinc. L'efficacite de materiaux mineraux, e.g. scories phosphatees, magnetite, maghemite, hematite, birnessite, oxyde de manganese hydrate, grenaille d'acier et beringite, pour diminuer la phytodisponibilite de Zn a ete etudiee en vase de vegetation avec un sol sableux contamine par des apports de boues urbaines. L'extractabilite et la phytodisponibilite de Zn ont ete determinees a l'aide d'une extraction selective au nitrate de calcium 0,1 M et de cultures de vegetaux, haricot nain (Phaseolus vulgaris L.) et raygrass (Lolium multiflorum). Un test de phytotoxicite, base sur les activites d'enzymes permettant a la plante de compenser des effets negatifs du zinc, a ete realise avec les feuilles primaires du haricot. D'apres le taux d'apport, la birnessite (10 g.kg -1 sol sec) a diminue le plus la quantite de Zn extractible du sol. La beringite produit un effet similaire, mais avec un taux de 50 g.kg -1 sol sec. Birnessite et beringite sont les traitements les plus efficaces pour diminuer le prelevement du zinc par le haricot et la phytotoxicite. Trois coupes successives du raygrass ont montre que la diminution du prelevement de Zn par la plante apres traitement du sol par la beringite persiste sur 5 mois. Avec la bimessite, l'accumulation de Zn dans les parties aeriennes du raygrass augmente a la troisieme coupe, redevenant similaire a celle des plantes cultivees sur le sol non traite.

ESR Investigation on the Breather Mode and the Spinon-Breather Dynamical Crossover in Cu Benzoate

Abstract: A "breather excitation" is observed directly by electron spin resonance in the quantum spin chain Cu benzoate, in which an unexpected field-induced gap has recently been found. The nonlinear field dependence of the resonance field agrees well with the formula based on a quantum sine-Gordon model. The power-law temperature dependence of the linewidth is observed in the gapless spinon regime while the width decreases exponentially for the gapped breather regime. In the intermediate range, a distinct anomaly is found, which is the manifestation of "the spinon-breather dynamical crossover."

Location strategies and evaluation of detection algorithms for earth faults in compensated MV distribution systems

Abstract: The compensation of MV distribution systems improves on the one hand the supply quality and imposes on the other hand higher constraints on earth fault detection and location strategies. Three new algorithms for the detection of permanent, resistive single phase earth faults are discussed. After a first implementation in the network, model testing showed the influence of important parameters on the algorithms accuracy, also for transient earth faults. Finally a novel strategy for fault location in compensated systems with a complex radial structure is outlined.

On the Ohsawa-Takegoshi-Manivel L2 extension theorem

Abstract: One of the goals of this work is to demonstrate in several different ways the strength of the fundamental tools introduced by Pierre Lelong for the study of Complex Analysis and Analytic or Algebraic Geometry. We first give a detailed presentation of the Ohsawa-Takegoshi L 2 extension theorem, inspired by a geometric viewpoint introduced by L. Manivel in 1993. Meanwhile, we simplify the original approach of the above authors, and point out a difficulty (yet to be overcome) in the regularity argument invoked by Manivel in bidegree (0, q), q ≥ 1. We then derive some striking consequences of the L2 extension theorem. In particular, we give an approximation theorem of plurisubharmonic functions by logarithms of holomorphic functions, preserving as much as possible the singularities and Lelong numbers of the given function. The study of plurisubharmonic singularities is pursued, leading to a new Briancon-Skoda type result concerning Nadel ‘s multiplier ideal sheaves. Using this result and some ideas of R Lazarsfeld, we finally give a new proof of a recent result of T. Fujita: the growth of the number of sections of multiples of a big line bundle is given by the highest power of the first Chern class of the numerically effective part in the line bundle Zariski decomposition.

Exponentially Accurate Semiclassical Dynamics: Propagation, Localization, Ehrenfest Times, Scattering, and More General States

Abstract: We prove six theorems concerning exponentially accurate semiclassical quantum mechanics. Two of these theorems are known results, but have new proofs. Under appropriate hypotheses, they conclude that the exact and approximate dynamics of an initially localized wave packet agree up to exponentially small errors in \( \hbar \) for finite times and for Ehrenfest times. Two other theorems state that for such times the wave packets are localized near a classical orbit up to exponentially small errors. The fifth theorem deals with infinite times and states an exponentially accurate scattering result. The sixth theorem provides extensions of the other five by allowing more general initial conditions.

Déformations formelles des revêtements sauvagement ramifiés de courbes algébriques

Abstract: In this paper we study formal moduli for wildly ramified Galois covering. We prove a local-global principle. We then focus on the infinitesimal deformations of the Z/pZ-covers. We explicitly compute a deformation of an automorphism of order p which implies a universal obstruction for p>2. By deforming Artin-Schreier equations we obtain a lower bound on the dimension of the local versal deformation ring. At last, by comparing the global versal deformation ring to the complete local ring in a point of a moduli space, we determine the dimensions of the global and local versal deformation rings.

The GIT-Equivalence for G-Line Bundles

Abstract: Let X be a projective variety with an action of a reductive group G. Each ample G-line bundle L on X defines an open subset Xss(L) of semi-stable points. Following Dolgachev and Hu, define a GIT-class as the set of algebraic equivalence classes of L's with fixed XssL. We show that the GIT-classes are the relative interiors of rational polyhedral convex cones, which form a fan in the G-ample cone. We also study the corresponding variations of quotients Xss(L)//G. This sharpens results of Thaddeus and Dolgachev-Hu.

Crustal structure of the continent-ocean transition off the Côte d'Ivoire-Ghana transform margin : implications for thermal exchanges across the palaeotransform boundary

Abstract: Summary Crustal structure of the continent–ocean transition off the Cote d'Ivoire–Ghana transform margin is determined by 2-D modelling of wide-angle seismic data and gravity data. The resulting models, together with geological data recently collected by drilling on the margin, are compared with available thermomechanical models of transform margins. In particular, we test the predicted effects on the transform margin crust of continental heating by the adjacent oceanic lithosphere. These effects include: (i) ductile flow of the lower continental crust either parallel to the transform direction or perpendicular to it, from the continent towards the ocean; and (ii) thermal uplift of the transform margin. In the region of the Cote d'Ivoire–Ghana transform margin, the seismic and gravity data indicate that the continental crust remains uniform in thickness as the continent–ocean boundary is approached. The interpreted models lack a transitional domain between continental and oceanic crusts, and abnormally thin oceanic crust is found along the margin. These results exclude large-scale ductile flow of lower continental crust during the margin formation. The geological data are, moreover, not consistent with thermal uplift of the margin during the period of contact between the transform margin and the spreading centre. Our geophysical and geological data thus infer only moderate heating of the transform continental margin by the adjacent oceanic lithosphere. Moderate heating of the Cote d'Ivoire–Ghana transform margin during margin formation implies that the thermal exchange between the transform margin and the adjacent spreading centre were lower than predicted by available thermal models. Two main factors may have contributed to reduce thermal exchanges across the continent–ocean boundary. The first factor is that the oceanic edge may have been colder than assumed by thermal models. An abnormally cold spreading axis along the transform margin when the oceanic crust was emplaced is supported by the atypical structure of the oceanic crust along the Cote d'Ivoire–Ghana transform margin. The oceanic crustal structure is similar to that found along oceanic fracture zones, where oceanic crust is’also’emplaced near a ridge–transform intersection. In both cases, abnormally low thermal gradients at the spreading centre along the transform margin may be explained by the cumulative effect of: (i) a cold edge effect of the adjacent continental lithosphere; (ii) accretion at the end of a ridge segment, away from the main magma supply point along the spreading axis; and (iii) an efficient upward cooling of the oceanic lithosphere owing to deep hydrothermal circulation within the faulted lithosphere. The second factor causing moderate thermal exchanges is the possibility of large amounts of water in oceanic lithospheric faults, which reduces the lateral thermal conduction in the lithosphere, since water is much less conductive than rock. During the margin formation, the oceanic edge thus seems to have acted as a thermal buffer between the cold continental margin and the hot spreading centre. We propose that this thermal buffer hypothesis may be generalized to most transform margins, implying a lower amount of continental heating than assumed by the available thermomechanical models.

Contribution of adenoviral-mediated superoxide dismutase gene transfer to the reduction in nitric oxide-induced cytotoxicity on human islets and INS-1 insulin-secreting cells.

Abstract: Aims/hypothesis. Vulnerability of pancreatic islets to oxygen free radicals and nitric oxide contributes to islet transplantation obstacles. This susceptibility can be linked to the low expression levels of antioxidant enzymes in islets. Our aim was to investigate the effect of overexpressing Cu/Zn superoxide dismutase in human islets through a simple procedure on the cytotoxic effects of two nitric oxide donors: 3-morpholinosydnonimine (SIN-1) and S-Nitroso-N-acetyl-d,l-penicillamine (SNAP). Methods. Cultured human islets and INS-1 rat-derived insulin-secreting cells were transfected by an E1-deleted adenovirus carrying Cu/Zn SOD cDNA under the control of a cytomegalovirus (CMV) promoter (AdSOD). The viability of the cells was tested by the WST-1 assay (Roche, Indianapolis, Ind., USA). Results. The AdSOD procedure allowed SOD activity to increase by twofold to threefold for 2 to 8 days following transfection. Adenovirus-driven SOD overexpression was associated with a significant reduction of SIN-1-induced cytotoxicity on human islets (69.9 ± 10.5 % protection at 200 μmol/l and 40.5 ± 8.9 % protection at 400 μmol/l) and INS-1 cells (82.2 ± 8.8 % protection at 200 μmol/l and 31.1 ± 5.8 % protection at 400 μmol/l). Protection against increasing doses of SNAP was AdSOD dose-dependent. Transfected islets released significantly more insulin than control islets in glucose-theophyllin-stimulated conditions, without or following exposure to SNAP. Conclusions/interpretation. We thus established that adenoviral-induced overexpression of Cu/Zn SOD can be beneficial to human islet endocrine function and resistance to nitric oxide cytotoxicity. These data could be relevant for the development of new strategies aimed at preventing NO-induced beta-cell damage in an islet transplantation setting. [Diabetologia (2000) 43: 625–631]

NMR determination of 2D electron spin polarization at nu = 1/2

Abstract: Using a "standard" NMR spin-echo technique we determined the spin polarization P of two-dimensional electrons, confined to GaAs quantum wells, from the hyperfine shift of Ga nuclei located in the wells. Concentrating on the temperature ( 0.05 less, similarT less, similar10 K) and magnetic field ( 7 less, similarB less, similar17 T) dependencies of P at Landau level filling factor nu = 1/2, we find that the results are described well by a simple model of noninteracting composite fermions, although some inconsistencies remain when the two-dimensional electron system is tilted in the magnetic field.

Role of duplex imaging in endovenous obliteration for primary venous insufficiency.

Abstract: Purpose:To assess the role of duplex imaging in defining suitable pathological anatomy for endovenous obliteration and characterizing its treatment outcomes over time.Methods:Eighteen lower limbs in 17 patients (12 women; mean age 48 years; range 29– 74 years) presenting with varicose greater saphenous veins (GSVs) were treated with endovenous obliteration without adjunctive high ligation. Duplex imaging was used as an intraprocedural guidance tool for vein access and catheter positioning and for preprocedural evaluation and serial surveillance after the procedures.Results:In the 18 limbs, preprocedural duplex scanning defined reflux owing to incompetence of the terminal valve (n = 6), subterminal valve (n = 9), or truncal valve (n = 3). Duplex imaging facilitated percutaneous vein puncture and was essential in catheter positioning at the saphenofemoral junction (SFJ). At 1 week, the saphenous trunks of all 18 limbs were either shrunken and obliterated (n = 7) or occluded by thrombus without shrinkage (n ...

Composition and chemical bonding of pulsed laser deposited carbon nitride thin films

Abstract: We studied composition, structure, and growth parameters of amorphous diamond-like carbon (DLC) and carbon nitride (CNx) films deposited by pulsed laser deposition in vacuum and in nitrogen atmosphere. The composition (0⩽N/C⩽0.4), the structural and the electronic properties of the deposited carbon and carbon nitride films were investigated for different laser fluences (1–12 J/cm2). Electron energy loss spectroscopy, x-ray photoelectron spectroscopy, and micro-Raman spectroscopy indicated an increase in sp3-bonded carbon sites in the DLC films and an increase in N-sp3 C bonded sites in the CNx films with increasing deposition laser fluence. Raman spectroscopy also showed the presence of a small amount of C≡N bonds in the CNx films. Furthermore, we observed that keeping the nitrogen pressure constant (P=100 mTorr) the increase in the deposition laser fluence is reflected by an increase in the nitrogen content in the films. All the results have been discussed in the framework of different theoretical models.

Personal exposure to atmospheric polycyclic aromatic hydrocarbons in a general adult population and lung cancer risk assessment.

Abstract: Personal exposure to nine particulate-phase atmospheric polycyclic aromatic hydrocarbons (PAHs) was assessed among adult non-smoking volunteers in the Grenoble, France, metropolitan area. Using Toxic Equivalency Factors, the associated total atmospheric PAHs lifelong cancer risk was estimated. For 48 hours continuously, 38 subjects without specific occupational exposure to combustion sources carried a PM 2.5 particles personal exposure monitor while at home, at work, commuting, or involved in other activities. One phase of the study took place in summer; a second in winter. The monitor set was composed of a pump with an airflow of 4 L. mn-1, a 2.5-μm cyclone, and Teflon filters. The PAH concentrations were determined on seven PM 2.5 filters by using high performance liquid chromatography with fluorimetric detection. The predominant PAHs are fluoranthene and indeno pyrene. According to the compound, the personal exposure estimates ranged from 0.13 to 1.67 ng/m 3 (yearly means). The average benzo(a) pyrene value is 0.67 ng/m 3 (95% confidence interval = 0 to 2.1 ng/m 3 ). Winter exposures were 3 to 25 times greater than summer exposures. The total PAHs lung cancer lifelong risk is 7.8 10 -5 and is driven by exposure to benzo(a) pyrene. Although these risk estimates are 2 to 3 orders of magnitude lower than those associated with specific occupational exposures in the coal or smelter industries, they are of public health concern because they are spread over large urban populations. Further personal exposure studies in adult or children populations are needed.