Boundary value problems for doubly perturbed first order ordinary differential systems

The aim of this paper is to present new results on existence theory for perturbed BVPs for first order ordinary differential systems. A nonlinear alternative for the sum of a contraction and a compact mapping is used

Existence of multiple nontrivial solutions for semilinear elliptic problems

AbstractThe aim of this paper is to prove the existence of multiple nontrivial solutions to a semilinear elliptic problem at resonance. The proofs used here are based on combining the Morse theory and the minimax methods

360 degree domain wall generation in the soft layer of magnetic tunnel junctions

High spatial resolution X-ray photo-emission electron microscopy technique has been used to study the influence of the dipolar coupling taking place between the NiFe and the Co ferromagnetic electrodes of micron sized, elliptical shaped magnetic tunnel junctions. The chemical selectivity of this technique allows to observe independently the magnetic domain structure in each ferromagnetic electrode. The combination of this powerful imaging technique with micromagnetic simulations allows to evidence that a 360 degree domain wall can be stabilized in the NiFe soft layer. In this letter, we discuss the origin and the formation conditions of those 360 degree domain walls evidenced experimentally and numerically

Kyste epidermoïde du quatrieme ventricule : a propos d’un cas

Les kystes épidermoïdes sont des tumeurs bénignes rares développées à partir d’inclusions ectodermiques. Ils siègent habituellement au niveau de l’angle ponto-cérébelleux, la région para-sellaire et la fosse temporale. Leur siège au niveau du quatrième ventricule est inhabituel. Nous rapportons le cas d’une jeune patiente de 44 ans admise pour un syndrome d’hypertension intracrânienne associé à des troubles de la marche. Le diagnostic de kyste épidermoïde du V4 fut évoqué sur les données de l’IRM puis confirmé en per opératoire et en histologie. L’exérèse chirurgicale a été subtotale en raison d’une adhérence de la capsule à la partie supérieure du plancher du V4. Après un recul de 18 mois, la patiente ne manifeste aucun signe de ré-évolution tumorale.Mots clés : chirurgie, IRM de diffusion, kyste épidermoïde, quatrième ventricl

Phytochemical screening and the antioxidant, antibacterial and antifungal activities of aqueous extracts from the leaves of Salvia officinalis planted in Morocco

The aqueous extract of the leaves of Salvia officinalis planted in Morocco is analyzed using different methods in order to study the different phytochemical components (phytochemical screening) and to test in parallel the antioxidant, antibacterial and antifungal activities. The main phytochemical components of salvia officinalis are: phenolics complex 13.87±1.96 mg E.AG/g, flavonoids 7.38±1.91mg E.Q/g and tannins 0.18±0.03 μg E.Cat/g, as well as different concentrations of saponins, alkaloids and mucilage.  The antioxidant activity is achieved by four different methods: the DPPH test (IC-50 = 8.2 μg/ml higher than BHT (1.2 μg/ml)); the ß-carotene decolorization test (the inhibition of oxidation of the aqueous extract (64.2%) was greater than the negative control (13. 87%)); the reducing power test (FRAP) (detection of a low reducing power of iron for the aqueous extract compared to quercetin) and the total antioxidant capacity (CAT), this test revealed an antioxidant capacity of 103.7±5.8 mg/g. The aqueous extract of salvia officinalis leaves showed antibacterial activity against four pathogenic bacteria: E. coli 57, K. pneumoniae, P. aeruginosa, S. aureus, noting MIC values of 0.25mg/ml; 0.125mg/ml; 0. The extract showed antifungal activity against two yeasts (S. sereveseae (0.25 mg/mlet C. albicans 0.25 mg/ml), using the agar diffusion method and the direct contact method

Hydatidose du rachis cervical : A propos d’un cas

L’hydatidose intéresse l’os dans 0,5 à 2 % des cas, dont 44 % de localisations au niveau rachidien. L’étage cervical est la moins fréquente des localisations rachidiennes. Cette atteinte est grave par le risque de compression médullaire haute, et surtout par son caractère récidivant. Les auteurs présentent l’observation d’un jeune patient admis pour une tétraplégie progressive, due à une hydatidose vertébro-médullaire cervicale ; son diagnostic a été évoquée sur l’imagerie par résonance magnétique et confirmée par l’étude anatomopathologique

Artificial Kagome Arrays of Nanomagnets: A Frozen Dipolar Spin Ice

Magnetic frustration effects in artificial kagome arrays of nanomagnets are investigated using x-ray photoemission electron microscopy and Monte Carlo simulations. Spin configurations of demagnetized networks reveal unambiguous signatures of long range, dipolar interaction between the nanomagnets. As soon as the system enters the spin ice manifold, the kagome dipolar spin ice model captures the observed physics, while the short range kagome spin ice model fails.Comment: 4 pages, 4 figures, 1 tabl

MCMC Algorithms for Supervised and Unsupervised Linear Unmixing of Hyperspectral Images

This book is a collection of 19 articles which reflect the courses given at the Collège de France/Summer school “Reconstruction d'images − Applications astrophysiques“ held in Nice and Fréjus, France, from June 18 to 22, 2012. The articles presented in this volume address emerging concepts and methods that are useful in the complex process of improving our knowledge of the celestial objects, including Earth