Showing papers by "University of Grenoble published in 2009"

Deep brain stimulation of the subthalamic nucleus for the treatment of Parkinson's disease

Abstract: High-frequency deep brain stimulation (DBS) of the subthalamic nucleus (STN-HFS) is the preferred surgical treatment for advanced Parkinson's disease. In the 15 years since its introduction into clinical practice, many studies have reported on its benefits, drawbacks, and insufficiencies. Despite limited evidence-based data, STN-HFS has been shown to be surgically safe, and improvements in dopaminergic drug-sensitive symptoms and reductions in subsequent drug dose and dyskinesias are well documented. However, the procedure is associated with adverse effects, mainly neurocognitive, and with side-effects created by spread of stimulation to surrounding structures, depending on the precise location of electrodes. Quality of life improves substantially, inducing sudden global changes in patients' lives, often requiring societal readaptation. STN-HFS is a powerful method that is currently unchallenged in the management of Parkinson's disease, but its long-term effects must be thoroughly assessed. Further improvements, through basic research and methodological innovations, should make it applicable to earlier stages of the disease and increase its availability to patients in developing countries.

Duration of androgen suppression in the treatment of prostate cancer.

Abstract: Background The combination of radiotherapy plus long-term medical suppression of androgens (≥2 years) improves overall survival in patients with locally advanced prostate cancer We compared the use of radiotherapy plus short-term androgen suppression with the use of radiotherapy plus long-term androgen suppression in the treatment of locally advanced prostate cancer Methods We randomly assigned patients with locally advanced prostate cancer who had received external-beam radiotherapy plus 6 months of androgen suppression to two groups, one to receive no further treatment (short-term suppression) and the other to receive 25 years of further treatment with a luteinizing hormone–releasing hormone agonist (long-term suppression) An outcome of noninferiority of short-term androgen suppression as compared with long-term suppression required a hazard ratio of more than 135 for overall survival, with a one-sided alpha level of 005 An interim analysis showed futility, and the results are presented with an a

Initial clinical manifestations of Parkinson's disease: features and pathophysiological mechanisms

Abstract: A dopaminergic deficiency in patients with Parkinson's disease (PD) causes abnormalities of movement, behaviour, learning, and emotions. The main motor features (ie, tremor, rigidity, and akinesia) are associated with a deficiency of dopamine in the posterior putamen and the motor circuit. Hypokinesia and bradykinesia might have a dual anatomo-functional basis: hypokinesia mediated by brainstem mechanisms and bradykinesia by cortical mechanisms. The classic pathophysiological model for PD (ie, hyperactivity in the globus pallidus pars interna and substantia nigra pars reticulata) does not explain rigidity and tremor, which might be caused by changes in primary motor cortex activity. Executive functions (ie, planning and problem solving) are also impaired in early PD, but are usually not clinically noticed. These impairments are associated with dopamine deficiency in the caudate nucleus and with dysfunction of the associative and other non-motor circuits. Apathy, anxiety, and depression are the main psychiatric manifestations in untreated PD, which might be caused by ventral striatum dopaminergic deficit and depletion of serotonin and norepinephrine. In this Review we discuss the motor, cognitive, and psychiatric manifestations associated with the dopaminergic deficiency in the early phase of the parkinsonian state and the different circuits implicated, and we propose distinct mechanisms to explain the wide clinical range of PD symptoms at the time of diagnosis.

The HARPS search for southern extra-solar planets: XVIII. An Earth-mass planet in the GJ 581 planetary system

Abstract: The GJ 581 planetary system was already known to harbour three planets, including two presumably rocky planets which straddle its habitable zone. We report here the detection of an additional planet ‐ GJ 581e ‐ with a minimum mass of 1.9 M" . With a period of 3.15 days, it is the innermost planet of the system and has a # 5% transit probability. We also correct our previous confusion of the orbital period of GJ 581d (the outermost planet) with a one-year alias, thanks to an extended time span and many more measurements. The revised period is 66.8 days, and locates the semi-major axis inside the habitable zone of the low mass star. The dynamical stability of the 4-planet system imposes an upper bound on the orbital plane inclination. The planets cannot be more massive than approximately 1.6 times their minimum mass.

General overview: European Integrated project on Aerosol Cloud Climate and Air Quality interactions (EUCAARI) - integrating aerosol research from nano to global scales

Abstract: In this paper we describe and summarize the main achievements of the European Aerosol Cloud Climate and Air Quality Interactions project (EUCAARI). EUCAARI started on 1 January 2007 and ended on 31 December 2010 leaving a rich legacy including: (a) a comprehensive database with a year of observations of the physical, chemical and optical properties of aerosol particles over Europe, (b) comprehensive aerosol measurements in four developing countries, (c) a database of airborne measurements of aerosols and clouds over Europe during May 2008, (d) comprehensive modeling tools to study aerosol processes fron nano to global scale and their effects on climate and air quality. In addition a new Pan-European aerosol emissions inventory was developed and evaluated, a new cluster spectrometer was built and tested in the field and several new aerosol parameterizations and computations modules for chemical transport and global climate models were developed and evaluated. These achievements and related studies have substantially improved our understanding and reduced the uncertainties of aerosol radiative forcing and air quality-climate interactions. The EUCAARI results can be utilized in European and global environmental policy to assess the aerosol impacts and the corresponding abatement strategies.

Observation of single top-quark production

Abstract: We report observation of the electroweak production of single top quarks in pp collisions at s=1.96 TeV based on 2.3 fb(-1) of data collected by the D0 detector at the Fermilab Tevatron Collider. Using events containing an isolated electron or muon and missing transverse energy, together with jets originating from the fragmentation of b quarks, we measure a cross section of sigma(pp -> tb+X,tqb+X)=3.94 +/- 0.88 pb. The probability to measure a cross section at this value or higher in the absence of signal is 2.5x10(-7), corresponding to a 5.0 standard deviation significance for the observation.

Exhumation Processes in Oceanic and Continental Subduction Contexts: A Review

Abstract: Although the exhumation of high pressure (HP) and ultrahigh pressure (UHP) rocks is an integral process in subduction, it is a transient process, likely taking place during the perturbation in subduction zones. Exhumation of HP to UHP rocks requires the weakening of a subduction channel and the decoupling of the exhumed slice from the rest of the slab. Considering more than 60 occurrences of HP to UHP units of Phanerozic ages, we propose three major types of subduction zones:

Pain assessment is associated with decreased duration of mechanical ventilation in the intensive care unit: a post Hoc analysis of the DOLOREA study.

Abstract: BACKGROUND: Critically ill patients frequently experience pain, but assessment rates remain below 40% in mechanically ventilated patients. Whether pain assessment affects patient outcomes is largely unknown. METHODS: As part of a prospective cohort study of mechanically ventilated patients who received analgesia on day 2 of their stay in the intensive care unit (ICU), the investigators performed propensity-adjusted score analysis to compare the duration of ventilator support and duration of ICU stay between 513 patients who were assessed for pain and 631 patients who were not assessed for pain. RESULTS: Patients assessed for pain on day 2 were more likely to receive sedation level assessment, nonopioids, and dedicated analgesia during painful procedures than patients whose pain was not assessed. They also received fewer hypnotics and lower daily doses of midazolam. Patients with pain assessment had a shorter duration of mechanical ventilation (8 vs. 11 days; P < 0.01) and a reduced duration of stay in the ICU (13 vs. 18 days; P < 0.01). In propensity-adjusted score analysis, pain assessment was associated with increased odds of weaning from the ventilator (odds ratio, 1.40; 95% confidence interval, 1.00-1.98) and of discharge from the ICU (odds ratio, 1.43; 95% confidence interval, 1.02-2.00). CONCLUSIONS: Pain assessment in mechanically ventilated patients is independently associated with a reduction in the duration of ventilator support and of duration of ICU stay. This might be related to higher concomitant rates of sedation assessments and a restricted use of hypnotic drugs when pain is assessed.

Radio Imaging of the Very-High-Energy gamma-Ray Emission Region in the Central Engine of a Radio Galaxy

Abstract: The accretion of matter onto a massive black hole is believed to feed the relativistic plasma jets found in many active galactic nuclei (AGN). Although some AGN accelerate particles to energies exceeding 10(12) electron volts and are bright sources of very-high-energy (VHE) gamma-ray emission, it is not yet known where the VHE emission originates. Here we report on radio and VHE observations of the radio galaxy Messier 87, revealing a period of extremely strong VHE gamma-ray flares accompanied by a strong increase of the radio flux from its nucleus. These results imply that charged particles are accelerated to very high energies in the immediate vicinity of the black hole.

Edge-preserving multiscale image decomposition based on local extrema

Abstract: We propose a new model for detail that inherently captures oscillations, a key property that distinguishes textures from individual edges. Inspired by techniques in empirical data analysis and morphological image analysis, we use the local extrema of the input image to extract information about oscillations: We define detail as oscillations between local minima and maxima. Building on the key observation that the spatial scale of oscillations are characterized by the density of local extrema, we develop an algorithm for decomposing images into multiple scales of superposed oscillations.Current edge-preserving image decompositions assume image detail to be low contrast variation. Consequently they apply filters that extract features with increasing contrast as successive layers of detail. As a result, they are unable to distinguish between high-contrast, fine-scale features and edges of similar contrast that are to be preserved. We compare our results with existing edge-preserving image decomposition algorithms and demonstrate exciting applications that are made possible by our new notion of detail.

Task-related gamma-band dynamics from an intracerebral perspective: review and implications for surface EEG and MEG.

Abstract: Although non-invasive techniques provide functional activation maps at ever-growing spatio-temporal precision, invasive recordings offer a unique opportunity for direct investigations of the fine-scale properties of neural mechanisms in focal neuronal populations. In this review we provide an overview of the field of intracranial Electroencephalography (iEEG) and discuss its strengths and limitations and its relationship to non-invasive brain mapping techniques. We discuss the characteristics of invasive data acquired from implanted epilepsy patients using stereotactic-electroencephalography (SEEG) and electrocorticography (ECoG) and the use of spectral analysis to reveal task-related modulations in multiple frequency components. Increasing evidence suggests that gamma-band activity (>40 Hz) might be a particularly efficient index for functional mapping. Moreover, the detection of high gamma activity may play a crucial role in bridging the gap between electrophysiology and functional imaging studies as well as in linking animal and human data. The present review also describes recent advances in real-time invasive detection of oscillatory modulations (including gamma activity) in humans. Furthermore, the implications of intracerebral findings on future non-invasive studies are discussed.

The SOPHIE search for northern extrasolar planets . I. A companion around HD 16760 with mass close to the planet/brown-dwarf transition

Abstract: We report on the discovery of a substellar companion or a massive Jupiter orbiting the G5V star HD 16760 using the spectrograph SOPHIE installed on the OHP 1.93-m telescope. Characteristics and performances of the spectrograph are presented, as well as the SOPHIE exoplanet consortium program. With a minimum mass of 14.3 MJup, an orbital period of 465 days and an eccentricity of 0.067, HD 16760b seems to be located just at the end of the mass distribution of giant planets, close to the planet/brown-dwarf transition. Its quite circular orbit supports a formation in a gaseous protoplanetary disk.

Electroexcitation of Nucleon Resonances from CLAS Data on Single Pion Electroproduction

Abstract: We present results on the electroexcitation of the low mass resonances $\ensuremath{\Delta}(1232){P}_{33}$, $N(1440){P}_{11}$, $N(1520){D}_{13}$, and $N(1535){S}_{11}$ in a wide range of ${Q}^{2}$. The results were obtained in the comprehensive analysis of data from the Continuous Electron Beam Accelerator Facility (CEBAF) large acceptance spectrometer (CLAS) detector at the Thomas Jefferson National Accelerator Facility (JLab) on differential cross sections, longitudinally polarized beam asymmetries, and longitudinal target and beam-target asymmetries for $\ensuremath{\pi}$ electroproduction off the proton. The data were analyzed using two conceptually different approaches---fixed-$t$ dispersion relations and a unitary isobar model---allowing us to draw conclusions on the model sensitivity of the obtained electrocoupling amplitudes. The amplitudes for the $\ensuremath{\Delta}(1232){P}_{33}$ show the importance of a meson-cloud contribution to quantitatively explain the magnetic dipole strength, as well as the electric and scalar quadrupole transitions. They do not show any tendency of approaching the pQCD regime for ${Q}^{2}\ensuremath{\leqslant}6$ GeV${}^{2}$. For the Roper resonance, $N(1440){P}_{11}$, the data provide strong evidence that this state is a predominantly radial excitation of a three-quark ($3q$) ground state. Measured in pion electroproduction, the transverse helicity amplitude for the $N(1535){S}_{11}$ allowed us to obtain the branching ratios of this state to the $\ensuremath{\pi}N$ and $\ensuremath{\eta}N$ channels via comparison with the results extracted from $\ensuremath{\eta}$ electroproduction. The extensive CLAS data also enabled the extraction of the ${\ensuremath{\gamma}}^{*}p\ensuremath{\rightarrow}N(1520){D}_{13}$ and $N(1535){S}_{11}$ longitudinal helicity amplitudes with good precision. For the $N(1535){S}_{11}$, these results became a challenge for quark models and may be indicative of large meson-cloud contributions or of representations of this state that differ from a $3q$ excitation. The transverse amplitudes for the $N(1520){D}_{13}$ clearly show the rapid changeover from helicity-3/2 dominance at the real photon point to helicity-1/2 dominance at ${Q}^{2}g1$ GeV${}^{2}$, confirming a long-standing prediction of the constituent quark model.

User-assisted intrinsic images

Abstract: For many computational photography applications, the lighting and materials in the scene are critical pieces of information. We seek to obtain intrinsic images, which decompose a photo into the product of an illumination component that represents lighting effects and a reflectance component that is the color of the observed material. This is an under-constrained problem and automatic methods are challenged by complex natural images. We describe a new approach that enables users to guide an optimization with simple indications such as regions of constant reflectance or illumination. Based on a simple assumption on local reflectance distributions, we derive a new propagation energy that enables a closed form solution using linear least-squares. We achieve fast performance by introducing a novel downsampling that preserves local color distributions. We demonstrate intrinsic image decomposition on a variety of images and show applications.

OGLE-2005-BLG-071Lb, THE MOST MASSIVE M DWARF PLANETARY COMPANION?

Abstract: We combine all available information to constrain the nature of OGLE-2005-BLG-071Lb, the second planet discovered by microlensing and the first in a high-magnification event. These include photometric and astrometric measurements from the Hubble Space Telescope, as well as constraints from higher order effects extracted from the ground-based light curve, such as microlens parallax, planetary orbital motion, and finite-source effects. Our primary analysis leads to the conclusion that the host of Jovian planet OGLE-2005-BLG-071Lb is an M dwarf in the foreground disk with mass M = 0.46 ± 0.04 Msun, distance Dl = 3.2 ± 0.4 kpc, and thick-disk kinematics vLSR ~ 103 km s‑1. From the best-fit model, the planet has mass Mp = 3.8 ± 0.4 MJupiter, lies at a projected separation r⊥ = 3.6 ± 0.2AU from its host, and so has an equilibrium temperature of T ~ 55 K, that is, similar to Neptune. A degenerate model gives similar planetary mass Mp = 3.4 ± 0.4 MJupiter with a smaller projected separation, r⊥ = 2.1 ± 0.1AU, and higher equilibrium temperature, T ~ 71 K. These results from the primary analysis suggest that OGLE-2005-BLG-071Lb is likely to be the most massive planet yet discovered that is hosted by an M dwarf. However, the formation of such high-mass planetary companions in the outer regions of M dwarf planetary systems is predicted to be unlikely within the core-accretion scenario. There are a number of caveats to this primary analysis, which assumes (based on real but limited evidence) that the unlensed light coincident with the source is actually due to the lens, that is, the planetary host. However, these caveats could mostly be resolved by a single astrometric measurement a few years after the event.

Exploring the molecular basis of insecticide resistance in the dengue vector Aedes aegypti : a case study in Martinique Island (French West Indies)

Abstract: The yellow fever mosquito Aedes aegypti is a major vector of dengue and hemorrhagic fevers, causing up to 100 million dengue infections every year. As there is still no medicine and efficient vaccine available, vector control largely based on insecticide treatments remains the only method to reduce dengue virus transmission. Unfortunately, vector control programs are facing operational challenges with mosquitoes becoming resistant to commonly used insecticides. Resistance of Ae. aegypti to chemical insecticides has been reported worldwide and the underlying molecular mechanisms, including the identification of enzymes involved in insecticide detoxification are not completely understood. The present paper investigates the molecular basis of insecticide resistance in a population of Ae. aegypti collected in Martinique (French West Indies). Bioassays with insecticides on adults and larvae revealed high levels of resistance to organophosphate and pyrethroid insecticides. Molecular screening for common insecticide target-site mutations showed a high frequency (71%) of the sodium channel 'knock down resistance' (kdr) mutation. Exposing mosquitoes to detoxification enzymes inhibitors prior to bioassays induced a significant increased susceptibility of mosquitoes to insecticides, revealing the presence of metabolic-based resistance mechanisms. This trend was biochemically confirmed by significant elevated activities of cytochrome P450 monooxygenases, glutathione S-transferases and carboxylesterases at both larval and adult stages. Utilization of the microarray Aedes Detox Chip containing probes for all members of detoxification and other insecticide resistance-related enzymes revealed the significant constitutive over-transcription of multiple detoxification genes at both larval and adult stages. The over-transcription of detoxification genes in the resistant strain was confirmed by using real-time quantitative RT-PCR. These results suggest that the high level of insecticide resistance found in Ae. aegypti mosquitoes from Martinique island is the consequence of both target-site and metabolic based resistance mechanisms. Insecticide resistance levels and associated mechanisms are discussed in relation with the environmental context of Martinique Island. These finding have important implications for dengue vector control in Martinique and emphasizes the need to develop new tools and strategies for maintaining an effective control of Aedes mosquito populations worldwide.

Bulk Universality for Wigner Matrices

Abstract: We consider $N\times N$ Hermitian Wigner random matrices $H$ where the probability density for each matrix element is given by the density $ u(x)= e^{- U(x)}$. We prove that the eigenvalue statistics in the bulk is given by Dyson sine kernel provided that $U \in C^6(\RR)$ with at most polynomially growing derivatives and $ u(x) \le C e^{- C |x|}$ for $x$ large. The proof is based upon an approximate time reversal of the Dyson Brownian motion combined with the convergence of the eigenvalue density to the Wigner semicircle law on short scales.

Edge-preserving Multiscale Image Decomposition based on Local Extrema

Abstract: We propose a new model for detail that inherently captures oscillations, a key property that distinguishes textures from individual edges. Inspired by techniques in empirical data analysis and morphological image analysis, we use the local extrema of the input image to extract information about oscillations: We define detail as oscillations between local minima and maxima. Building on the key observation that the spatial scale of oscillations are characterized by the density of local extrema, we develop an algorithm for decomposing images into multiple scales of superposed oscillations.Current edge-preserving image decompositions assume image detail to be low contrast variation. Consequently they apply filters that extract features with increasing contrast as successive layers of detail. As a result, they are unable to distinguish between high-contrast, fine-scale features and edges of similar contrast that are to be preserved. We compare our results with existing edge-preserving image decomposition algorithms and demonstrate exciting applications that are made possible by our new notion of detail.

On the correlation of non-isotropically distributed ballistic scalar diffuse waves

Abstract: Theorems indicating that a fully equipartitioned random wave field will have correlations equivalent to the Green’s function that would be obtained in an active measurement are now legion. Studies with seismic waves, ocean acoustics, and laboratory ultrasound have confirmed them. So motivated, seismologists have evaluated apparent seismic travel times in correlations of ambient seismic noise and tomographically constructed impressive maps of seismic wave velocity. Inasmuch as the random seismic waves used in these evaluations are usually not fully equipartitioned, it seems right to ask why it works so well, or even if the results are trustworthy. The error, in apparent travel time, due to non-isotropic specific intensity is evaluated here in a limit of large receiver-receiver separation and for the case in which the source of the noise is in the far field of both receivers. It is shown that the effect is small, even for cases in which one might have considered the anisotropy to be significant, and even fo...

Assessing pain in non-intubated critically ill patients unable to self report: an adaptation of the Behavioral Pain Scale

Abstract: Purpose To validate an adaptation of the Behavioral Pain Scale (BPS) for its use in non-intubated intensive care unit (ICU) patients unable to self-report their pain because of the occurrence of delirium. The “vocalization” domain was inserted to construct the BPS-non intubated (BPS-NI) scale, ranging from 3 (no pain) to 12 (most pain).

Reachability Analysis of Hybrid Systems Using Support Functions

Abstract: This paper deals with conservative reachability analysis of a class of hybrid systems with continuous dynamics described by linear differential inclusions, convex invariants and guards, and linear reset maps. We present an approach for computing over-approximations of the set of reachable states. It is based on the notion of support function and thus it allows us to consider invariants, guards and constraints on continuous inputs and initial states defined by arbitrary compact convex sets. We show how the properties of support functions make it possible to derive an effective algorithm for approximate reachability analysis of hybrid systems. We use our approach on some examples including the navigation benchmark for hybrid systems verification.

Photometric and spectroscopic detection of the primary transit of the 111-day-period planet HD 80 606 b

Abstract: We report the detection of the primary transit of the extra-solar planet HD 80 606 b, thanks to photometric and spectroscopic observations performed at the Observatoire de Haute-Provence, simultaneously with the CCD camera at the 120-cm telescope and the SOPHIE spectrograph on the 193-cm telescope. We observed the whole egress of the transit and partially its central part, in both datasets with the same timings. The ingress occurred before sunset so was not observed. The full duration of the transit was between 9.5 and 17.2 h. The data allows the planetary radius to be measured ($R_{\mathrm{p}} = 0.9 \pm 0.10\,{R}_{\rm Jup}$) and other parameters of the system to be refined. Radial velocity measurements show the detection of a prograde Rossiter-McLaughlin effect, and provide a hint of a spin-orbit misalignment. If confirmed, this misalignment would corroborate the hypothesis that HD 80 606 b owes its unusual orbital configuration to Kozai migration. HD 80 606 b is by far the transiting planet on the longest period detected today. Its unusually small radius reinforces the observed relationship between the planet radius and the incident flux received from the star and opens new questions for theory. Orbiting a bright star ($V=9$), it opens opportunities for numerous follow-up studies.

A simple approach to nonlinear tensile stiffness for accurate cloth simulation

Abstract: Recent mechanical models for cloth simulation have evolved toward accurate representation of elastic stiffness based on continuum mechanics, converging to formulations that are largely analogous to fast finite element methods. In the context of tensile deformations, these formulations usually involve the linearization of tensors, so as to express linear elasticity in a simple way. However, this approach needs significant adaptations and approximations for dealing with the nonlinearities resulting from large cloth deformations. Toward our objective of accurately simulating the nonlinear properties of cloth, we show that this linearization can indeed be avoided and replaced by adapted strain-stress laws that precisely describe the nonlinear behavior of the material. This leads to highly streamlined computations that are particularly efficient for simulating the nonlinear anisotropic tensile elasticity of highly deformable surfaces. We demonstrate the efficiency of this method with examples related to accurate garment simulation from experimental tensile curves measured on actual materials.