Nearfield Acoustic Holography using sparsity and compressive sampling principles

Regularization of the inverse problem is a complex issue when using Near-field Acoustic Holography (NAH) techniques to identify the vibrating sources. This paper shows that, for convex homogeneous plates with arbitrary boundary conditions, new regularization schemes can be developed, based on the sparsity of the normal velocity of the plate in a well-designed basis, i.e. the possibility to approximate it as a weighted sum of few elementary basis functions. In particular, these new techniques can handle discontinuities of the velocity field at the boundaries, which can be problematic with standard techniques. This comes at the cost of a higher computational complexity to solve the associated optimization problem, though it remains easily tractable with out-of-the-box software. Furthermore, this sparsity framework allows us to take advantage of the concept of Compressive Sampling: under some conditions on the sampling process (here, the design of a random array, which can be numerically and experimentally validated), it is possible to reconstruct the sparse signals with significantly less measurements (i.e., microphones) than classically required. After introducing the different concepts, this paper presents numerical and experimental results of NAH with two plate geometries, and compares the advantages and limitations of these sparsity-based techniques over standard Tikhonov regularization.Comment: Journal of the Acoustical Society of America (2012

Transforming an Intractable Conflict by the Multi-Track Diplomacy Approach: Application to the Taiwan Strait Conflict

The primary cause was the control of Chinese territory. The two political groups in Taiwan (Chinese Nationalist Party or KMT and the Democratic Progressive Party or DPP) and China are the main actors whereas Japan and the United States are the secondary actors. The conflict has escalated into war, crises and unstable peace with 4 main climaxes. The initial issue was the sovereignty dispute over China and Chinese people in both territories of the mainland China and the island of Taiwan. Due to the de-Sinification and the Taiwanisation policies as well as divergent socio-political and economic developments, the issue has evolved into cultural and political identity issue creating 3 identifiers: few Chinese, more Taiwanese and some ‘Chiwanese’. Peacemaking process: The United States has prevented a reunification war; the tracks 2, 3 and 4 diplomacy have advanced the economic interdependence and social interactions with no political reunification. Policy recommendations: all the actors (China, KMT, DPP and US) need to change their policies, mainly by reviewing the “one China, different interpretations” principle, establishing a trilateral relationship, and supporting Taiwan’s participation into international organizations. This can be achieved by applying all the nine tracts of the multitrack diplomacy (MTD) approach

New insight into the role of phosphodiesterase 3A in porcine oocyte maturation

BACKGROUND: The ovulatory surge of gonadotropins triggers oocyte maturation and rupture of the ovarian follicle. The resumption of nuclear maturation in the oocyte from the prophase stage is characterized by germinal vesicle breakdown (GVBD). It has previously been shown that specific inhibition of cAMP degradation by PDE3 prevents the resumption of oocyte meiosis. However, no report has characterized the activity of PDE3 in the porcine oocyte, or the implication of the cAMP-PDE3 pathway in the entire nuclear maturation process. In this study, PDE3 activity in the oocyte was assessed during in vitro maturation (IVM) and the possible roles of the cAMP-PDE3 pathway in the resumption and progression of meiosis were investigated in terms of different models of oocyte maturation. RESULTS: Cyclic AMP-degrading PDE activity was detected in the cumulus-oocyte complex (COC) and was partially inhibited by a specific PDE3 inhibitor, cilostamide. When measured only in the denuded oocyte, PDE activity was almost completely inhibited by cilostamide, suggesting that cAMP-PDE3 activity is the major cAMP-PDE in porcine oocytes. PDE3A mRNA was detected by RT-PCR. PDE3 activity did not vary significantly during the early hours of IVM, but a maximum was observed at 13 hours. In cumulus-oocyte complexes, meiosis resumed after 20.81 hours of culture. PDE3 inhibition no longer maintained meiotic arrest if sustained beyond 17.65 hours of IVM, 3 hours prior to resumption of meiosis. Thereafter, PDE3 inhibition progressively lost its efficacy in GVBD. When the protein phosphatase 1 and 2A inhibitor okadaic acid was continuously or transiently (3 hours) present during IVM, meiosis resumed prematurely; PDE3 inhibition was unable to prevent GVBD. However, PDE3 inhibition in COC treated with OA for 3 hours significantly delayed meiosis at the intermediate stage. CONCLUSION: The present investigation has demonstrated that PDE3A is the major cAMP-degrading PDE in the oocyte. It regulates the resumption of meiosis until 3 hours prior to GVBD and transiently affects meiotic progression

Histoire sociale de l’Amérique du Nord

François Weil, directeur d’études Migrants et migrations de France aux Amériques Le séminaire, qui s’est tenu à partir du mois de janvier 2004 (le directeur d’études était invité à l’automne 2003 sur la chaire Andrew W. Mellon à l’Université Tulane de la Nouvelle-Orléans, où il a animé un séminaire de recherche sur l’histoire de la Louisiane française du XVIIIe au XXe siècle et organisé une série de colloques et de conférences), a permis de reprendre à nouveaux frais un ensemble de dossiers t..

Estimation of a maximum Lu diffusion rate in a natural eclogite garnet

Lutetium zoning in garnet within eclogites from the Zermatt-Saas Fee zone, Western Alps, reveal sharp, exponentially decreasing central peaks. They can be used to constrain maximum Lu volume diffusion in garnets. A prograde garnet growth temperature interval of ~450-600 °C has been estimated based on pseudosection calculations and garnet-clinopyroxene thermometry. The maximum pre-exponential diffusion coefficient which fits the measured central peak is in the order of D0=5.7*10−6 m2/s, taking an estimated activation energy of 270kJ/mol based on diffusion experiments for other rare earth elements in garnet. This corresponds to a maximum diffusion rate of D (~600 °C) = 4.0*10-22 m2/s. The diffusion estimate of Lu can be used to estimate the minimum closure temperature, Tc, for Sm-Nd and Lu-Hf age data that have been obtained in eclogites of the Western Alps, postulating, based on a literature review, that D (Hf)< D (Nd) <D (Sm) ≤ D (Lu). Tc calculations, using the Dodson equation, yielded minimum closure temperatures of about 630 °C, assuming a rapid initial exhumation rate of 50°/m.y., and an average crystal size of garnets (r = 1mm). This suggests that Sm/Nd and Lu/Hf isochron age differences in eclogites from the Western Alps, where peak temperatures did rarely exceed 600 °C must be interpreted in terms of prograde metamorphis

First applications of sound-based control on a mobile robot equipped with two microphones

International audience— This paper validates experimentally a novel approach to robot audition, sound-based control, which consists in introducing auditory features directly as inputs of a closed-loop control scheme, that is, without any explicit localization process. The applications we present rely on the implicit bearings of the sound sources computed from the time difference of arrival (TDOA) between two microphones. By linking the motion of the robot to the aural perception of the environment, this approach has the benefit of being more robust to reverberation and noise. Therefore neither complex tracking method such as Kalman filtering nor TDOA enhancement with denoising or dereverberation methods are needed to track the correct TDOA measurements. The experiments conducted on a mobile robot instrumented with a pair of microphones show the validity of our approach. In a reverberating and noisy room, this approach is able to orient the robot to a mobile sound source in real time. A positioning task with respect to two sound sources is also performed while the robot perception is disturbed by altered and spurious TDOA measurements

Les exercices physiques réguliers ont-ils un effet bénéfique dans le TDAH chez l’enfant et l’adolescent ?

editorial reviewe

Les thérapies cognitivo-comportementales sont- elles plus efficaces que les autres traitements de la dépression ?

editorial reviewe

Les professionnels de la santé de la première ligne de soins ont-ils un impact sur l’activité physique de la population générale ?

editorial reviewe

Depressive Symptoms and 24-Hour Ambulatory Blood Pressure in Africans: The SABPA Study

Disturbances in circadian rhythm might play a central role in the neurobiology of depression. We examined the association between depressive symptoms and 24-hour ambulatory BP in a sample of 405 (197 black and 208 Caucasian) urbanized African teachers aged 25 to 60 yrs (mean 44.6 ± 9.6 yrs). Depressive symptoms were assessed using the self-administered 9-item Patient Health Questionnaire (PHQ-9). After adjusting for age, sex, and ethnicity, participants with severe depressive symptoms (PHQ-9 ≥ 15) had higher odds of hypertension defined from ambulatory BP and/or use of antihypertensive medication (odds ratio = 2.19, 95% CI, 1.00–4.90) in comparison to participants with no symptoms. Compared to Caucasians with no depressive symptoms, those with severe symptoms had blunted nocturnal systolic BP drop of 4.7 mmHg (95% CI, −0.5 to 10.0, P = 0.07). In summary, depressive symptoms were associated with the circadian BP profile in black and Caucasian Africans