Global Solutions for the Gravity Water Waves Equation in Dimension 3

We show existence of global solutions for the gravity water waves equation in dimension 3, in the case of small data. The proof combines energy estimates, which yield control of L^2 related norms, with dispersive estimates, which give decay in L^\infty. To obtain these dispersive estimates, we use an analysis in Fourier space; the study of space and time resonances is then the crucial point

Uniform regularity for the Navier-Stokes equation with Navier boundary condition

We prove that there exists an interval of time which is uniform in the vanishing viscosity limit and for which the Navier-Stokes equation with Navier boundary condition has a strong solution. This solution is uniformly bounded in a conormal Sobolev space and has only one normal derivative bounded in $L^\infty$. This allows to get the vanishing viscosity limit to the incompressible Euler system from a strong compactness argument

Unexpected stimulation of mitochondrial ADP-ribosylation by cyanide

AbstractCyanide, the classical inhibitor of the mitochondrial respiratory chain at site III, stimulates ADP-ribosylation of a number of mitochondrial proteins, the major protein being the 50–55 kDa band. Sodium azide, sharing the same inhibitory site, does not have the same effect. Rotenone or antimycin A have no influence on mitochondrial ADP-ribosylation. Data suggest that no apparent correlation exists between oxidoreductase function and protein ADP-ribosylation. Purified nuclear poly(ADP-ribose) polymerase activity was not affected by cyanide. The cyanide effect on mitochondrial ADP-ribosylation seems intriguing and may be attributed to NAD+ -CN complex formation, since NAD reacts with cyanide at pH > 8 with N-substituted nicotinamide which may prevent inhibition of ADP-ribosylation

A bio-inspired image coder with temporal scalability

We present a novel bio-inspired and dynamic coding scheme for static images. Our coder aims at reproducing the main steps of the visual stimulus processing in the mammalian retina taking into account its time behavior. The main novelty of this work is to show how to exploit the time behavior of the retina cells to ensure, in a simple way, scalability and bit allocation. To do so, our main source of inspiration will be the biologically plausible retina model called Virtual Retina. Following a similar structure, our model has two stages. The first stage is an image transform which is performed by the outer layers in the retina. Here it is modelled by filtering the image with a bank of difference of Gaussians with time-delays. The second stage is a time-dependent analog-to-digital conversion which is performed by the inner layers in the retina. Thanks to its conception, our coder enables scalability and bit allocation across time. Also, our decoded images do not show annoying artefacts such as ringing and block effects. As a whole, this article shows how to capture the main properties of a biological system, here the retina, in order to design a new efficient coder.Comment: 12 pages; Advanced Concepts for Intelligent Vision Systems (ACIVS 2011

Root distribution in young olive trees (Olea europaea cv. Chétoui) and agronomic application

The study was carried out to have a comprehensive view of the root system behavior of young olive trees cultivated under field conditions. The experiment involved irrigated trees (Olea europaea L., cv., Chétoui) cultivated at 6x6 m2 spacing in Mornag (36.5°N, 10.2°E), northern Tunisia. The way in which roots explore the soil volume during the first years after planting was explored through ‘in situ’ root system drawings and estimation of root densities. The relationship between canopy and root growth parameters was also investigated. The last section of this paper proposes a methodological approach for determining irrigation requirements of young olive trees and how water supply could be linked to the development of canopy and root system during the first years of cultivation when ground cover and the root system are not completely developed. Some agronomic applications were then deduced concerning water and fertilizers for such orchards. Results show that the main development of the olive root system occurs during the two to four first years of cultivation confining most roots (70%) to the top soil layers (20-40 cm). Maximum root densities were observed at this depth at a distance of 0.4 m from trunks. For young trees, water and fertilizers should be supplied at these depths and distances from trunk to allow easy and efficient root absorption. Obtained results also show a significant relationship between canopy and root areas which can be approximated by a linear model (r = 0.94). The root-canopy ratio estimated from their areas decreased rapidly beginning from the second year after planting, resulting from the establishment of competition between vegetative growth and fruiting. The optimum ratio root length/leaf canopy area of 2.3 km m-2 was found for the six-year-old tree indicating good equilibrium between the above and underground parts. The mathematical model developed on the basis of canopy cover and root extension allows precise esti- mation of water needs taking into account the actual root surface. However, while the canopy cover measurement was relatively easy to carry out, it was much more difficult to determine the surface covered by the root system. Results obtained in the present work also show an over-estimation of water needs when the FAO method is adopted to estimate the evapotranspiration of young trees

Inviscid incompressible limits of the full Navier-Stokes-Fourier system

We consider the full Navier-Stokes-Fourier system in the singular limit for the small Mach and large Reynolds and Peclet numbers, with ill prepared initial data on the three dimensional Euclidean space. The Euler-Boussinesq approximation is identified as the limit system

Privacy preserving cooperative computation for personalized web search applications

With the emergence of connected objects and the development of Artificial Intelligence (AI) mechanisms and algorithms, personalized applications are gaining an expanding interest, providing services tailored to each single user needs and expectations. They mainly rely on the massive collection of personal data generated by a large number of applications hosted from different connected devices. In this paper, we present CoWSA, a privacy preserving Cooperative computation framework for personalized Web Search peripheral Applications. The proposed framework is multi-fold. First, it provides the empowerment to end-users to control the disclosed personal data to third parties, while leveraging the trade-off between privacy and utility. Second, as a decentralized solution, CoWSA mitigates single points of failures, while ensuring the security of queries, the anonymity of submitting users, and the incentive of contributing nodes. Third, CoWSA is scalable as it provides acceptable computation and communication costs compared to most closely related schemes

Prevalence and risk factors of low back pain among undergraduate students of a sports and physical education institute in Tunisia

Introduction: For obvious reasons, athletes are at greater risk of sustaining a lumber (lower) spine injury due to physical activity. To our knowledge, no previous studies have examined the prevalence of low back pain (LBP) in a Tunisian sports and physical education institute.Aim: To assess the prevalence of LBP in different sports among students studying in a sports and physical education institute in Tunisia, to determine the causes of the injuries, and to propose solutions.Methods: A total of 3,379 boys and 2,579 girls were studied. A retrospective cross-sectional survey was conducted on a group of students aged 18.524.5 years at the Higher Institute of Sport and Physical Education of Sfax to estimate the prevalence of LBP and its relation to the type of sports. Data on age, weight, height, smoking, and the sport in which the student was injured in the low back were collected from the institute health service records from 2005 until 2013.Results: LBP was reported by 879 of the 5,958 study participants (14.8%). The prevalence of LBP was significantly higher (pB0.001) in females (17.6%) than in males (12.5%). LBP prevalence did not differ by body mass index or smoking habit (p0.05). The sports associated with the higher rates of LBP were gymnastics, judo, handball, and volleyball, followed by basketball and athletics.Conclusion: LBP is frequent among undergraduate students of a sports and physical education institute in Tunisia. It is strongly associated with fatigue after the long periods of training in different sports. Gymnastics, judo, handball, and volleyball were identified as high-risk sports for causing LBP.Keywords: low back pain; sports students; sports training; risk factor

Efficient Architecture and Implementation of Vector Median Filter in Co-Design Context

This work presents an efficient fast parallel architecture of the Vector Median Filter (VMF) using combined hardware/software (HW/SW) implementation. The hardware part of the system is implemented using VHDL language, whereas the software part is developed using C/C++ language. The software part of the embedded system uses the NIOS-II softcore processor and the operating system used is μClinux. The comparison between the software and HW/SW solutions shows that adding a hardware part in the design attempts to speed up the filtering process compared to the software solution. This efficient embedded system implementation can perform well in several image processing applications