Monitoring of Rehabilitation of Degraded Rangelands

The Algerian steppe covers an area of about 20 million ha, and is the barrier between the desert and the Mediterranean region. With more than 20 million sheep, overgrazing is an important issue resulting in continued degradation of the natural resources (Nedjraoui and Bedrani 2008). Trials of the rehabilitation of these ecosystems were undertaken in a participatory process with farmers complemented by some detailed monitoring of the responses in experimental plots (Hammouda 2009; Bouchareb 2012). This study reports on some results of the ecological monitoring and evaluation for a participatory project, in the steppe of South Algiers, conducted by a multidisciplinary team

Absorption cross section in warped AdS_3 black hole revisited

We investigate the absorption cross section for minimal-coupled scalars in the warped AdS_3 black hole. According to our calculation, the cross section reduces to the horizon area in the low energy limit as usually expected in contrast to what was previously found. We also calculate the greybody factor and find that the effective temperatures for the two chiral CFT's are consistent with that derived from the quasinormal modes. Observing the conjectured warped AdS/CFT correspondence, we suspect that a specific sector of the CFT operators with the desired conformal dimension could be responsible for the peculiar thermal behaviour of the warped AdS_3 black hole.Comment: 16+1 pages, typos corrected, references and footnotes adde

Geometric Finiteness, Holography and Quasinormal Modes for the Warped AdS_3 Black Hole

We show that there exists a precise kinematical notion of holography for the Euclidean warped $AdS_3$ black hole. This follows from the fact that the Euclidean warped $AdS_3$ black hole spacetime is a geometrically finite hyperbolic manifold. For such manifolds a theorem of Sullivan provides a one-to-one correspondence between the hyperbolic structure in the bulk and the conformal structure of its boundary. Using this theorem we obtain the holographic quasinormal modes for the warped $AdS_3$ black hole.Comment: Latex file, 7 pages. Journal versio

LE DOSAGE DE L’HEMOGLOBINE GLYQUEE POUR UNE MEILLEURE SURVEILLANCE DE L’EQUILIBRE GLYCEMIQUE CHEZ L’ENFANT. ETUDE CHEZ 55 ENFANTS

The diabetic patients treatments need to be continuously adjusted by frequent urinary glucose controls (3-4 times/day and 1 time/month). The repetition of such tests is not accepted by the child and that is a timely diabetic balance reflection. The purpose of this work is to verify the prognostic value of the glycated hemoglobin test, which occurs every eight weeks, in the monitoring of the diabetic child balance. We used for this study a sample of 27 control children and 28 diabetics children followed in the diabete pediatric unit at the hospital Sid' Soufi in Casablanca. In this sample were churched the correlations between the glycated hemoglobin and the fasting blood glucose, the 24 hours glucosuries, the semi-quantitative glucosuries, the cholesterol and the triglycerides blood levels. Our results showed a significant correlation between the level of glycated hemoglobin and all the constants tested except the cholesterol. We concluded that the test of the glycated hemoglobin is a reliable method of glycemia balance monitoring in diabetic child.Les traitements utilisés chez le diabétique ont besoin d’être réajustés de façon continue par des contrôles urinaires fréquents de la glycémie (3- 4 fois/jour et 1 fois/mois). La répétition de ces contrôles est mal acceptée par l’enfant et par sa famille ; d’autant plus que ce n’est qu’un reflet ponctuel de l'équilibre diabétique. L’objet de ce travail est de vérifier la valeur pronostique du dosage de l'hémoglobine glyquée, qui a lieu seulement toutes les huit semaines, dans la surveillance de l’équilibre diabétique de l’enfant. Nous avons utilisé pour cette étude un échantillon de 27 enfants contrôles et 28 enfants diabétiques suivis dans l'unité de diabétologie du service de pédiatrie de l'hôpital Sid' Soufi à Casablanca. Sur cet échantillon, ont été recherché la corrélation entre l’hémoglobine glyquée et la glycémie à jeun, les glucosuries sur 24 heures, les glucosuries semi-quantitatives antérieures au dosage de l’hémoglobine glyquée, le taux de cholestérol et des triglycérides dans le sang. Nos résultats ont montré une corrélation significative entre le taux de l’hémoglobine glyquée et toutes les constantes testées sauf le cholestérol. Nous avons conclu que le test de l’hémoglobine glyquée est une méthode de surveillance fiable et bien adaptée au contrôle de l’équilibre diabétique chez l’enfant

Area spectra versus entropy spectra in black holes in topologically massive gravity

We consider the area and entropy spectra of black holes in topologically massive gravity with gravitational Chern-Simons term. The examples we consider are the BTZ black hole and the warped AdS black hole. For the non-rotating BTZ black hole, the area and entropy spectra are equally spaced and independent of the coupling constant \v of the Chern-Simons term. For the rotating BTZ black hole case, the spectra of the inner and outer horizon areas are not equally spaced in general and dependent of the coupling constant \v. However the entropy spectrum is equally spaced and independent of the coupling constant \v. For the warped AdS black holes for $\v >1$ by using the quasinormal modes obtained without imposing the boundary condition at radial infinity we find again that the entropy spectrum is equally spaced and independent of the coupling constant \v, while the spectra of the inner and outer horizon areas are not equally spaced and dependent of the coupling constant \v. Our result implies that the entropy spectrum has a universal behavior regardless of the presence of the gravitational Chern-Simons term, and therefore it implies that the entropy is more `fundamental' than the horizon area.Comment: 16 page

Uniqueness and nonuniqueness of the stationary black holes in 5D Einstein-Maxwell and Einstein-Maxwell-dilaton gravity

In the present paper we investigate the general problem of uniqueness of the stationary black solutions in 5D Einstein-Maxwell-dilaton gravity with arbitrary dilaton coupling parameter containing the Einstein-Maxwell gravity as a particular case. We formulate and prove uniqueness theorems classifying the stationary black hole solutions in terms of their interval structure, electric and magnetic charges and the magnetic fluxes. The proofs are based on the nonpositivity of the Riemann curvature operator on the space of the potentials which imposes restrictions on the dilaton coupling parameter.Comment: 21 pages, LaTe

Quasi-normal modes of warped black holes and warped AdS/CFT correspondence

We analytically calculate the quasi-normal modes of various perturbations of spacelike stretched and null warped $AdS_3$ black holes. From AdS/CFT correspondence, these quasi-normal modes are expected to appear as the poles in momentum space of retarded Green functions of dual operators in CFT at finite temperature. We find that this is indeed the case, after taking into account of the subtle identification of quantum numbers. The subtlety comes from the fact that only after appropriate coordinate transformation the asymptotic geometries of warped black holes are the same as the ones of warped $AdS_3$ spacetimes. We show that in general the quasi-normal modes are in good agreement with the prediction of the warped AdS/CFT correspondence, up to a constant factor. As a byproduct, we compute the conformal dimensions of boundary operators dual to the perturbations. Our result gives strong support to the conjectured warped AdS/CFT correspondence.Comment: 26 pages; typos corrected, references added; more clarifications, match the version to appear in JHE

Nonpropagation of massive mode on AdS2 in topologically massive gravity

Making use of Achucarro-Ortiz (AO) type of dimensional reduction, we study the topologically massive gravity with a negative cosmological constant on AdS2 spacetimes. For a constant dilaton, this two-dimensional model also admits three AdS2 vacuum solutions, which are related to two AdS3 and warped AdS3 backgrounds with an identification upon uplifting three dimensions. We carry out the perturbation analysis around these backgrounds to find what is a physically propagating field. However, it turns out that there is no propagating massive mode on AdS2 background, in contrast to the Kaluza-Klein (KK) type of dimensional reduction. We note that two dimensionally reduced actions are different and thus, the non-equivalence of their on-shell amplitudes is obtained.Comment: 19 pages, version to appear in EPJ

Holography For a De Sitter-Esque Geometry

Warped dS$_3$ arises as a solution to topologically massive gravity (TMG) with positive cosmological constant $+1/\ell^2$ and Chern-Simons coefficient $1/\mu$ in the region $\mu^2 \ell^2 < 27$. It is given by a real line fibration over two-dimensional de Sitter space and is equivalent to the rotating Nariai geometry at fixed polar angle. We study the thermodynamic and asymptotic structure of a family of geometries with warped dS$_3$ asymptotics. Interestingly, these solutions have both a cosmological horizon and an internal one, and their entropy is unbounded from above unlike black holes in regular de Sitter space. The asymptotic symmetry group resides at future infinity and is given by a semi-direct product of a Virasoro algebra and a current algebra. The right moving central charge vanishes when $\mu^2 \ell^2 = 27/5$. We discuss the possible holographic interpretation of these de Sitter-esque spacetimes.Comment: 22 pages, 1 figure; v2: typos corrected, to match with published versio

Spectrum Generating Conformal and Quasiconformal U-Duality Groups, Supergravity and Spherical Vectors

After reviewing the algebraic structures that underlie the geometries of N=2 Maxwell-Einstein supergravity theories (MESGT) in five and four dimensions with symmetric scalar manifolds, we give a unified realization of their three dimensional U-duality groups as spectrum generating quasiconformal groups. They are F_{4(4)}, E_{6(2)}, E_{7(-5)}, E_{8(-24)} and SO(n+2,4). Our formulation is covariant with respect to U-duality symmetry groups of corresponding five dimensional supergravity theories, which are SL(3,R), SL(3,C), SU*(6), E_{6(6)} and SO(n-1,1)X SO(1,1), respectively. We determine the spherical vectors of quasiconformal realizations of all these groups twisted by a unitary character. We also give their quadratic Casimir operators and determine their values. Our work lays the algebraic groundwork for constructing the unitary representations of these groups induced by their geometric quasiconformal actions, which include the quaternionic discrete series. For rank 2 cases, SU(2,1) and G_{2(2)}, corresponding to simple N=2 supergravity in four and five dimensions, this program was carried out in arXiv:0707.1669. We also discuss the corresponding algebraic structures underlying symmetries of matter coupled N=4 and N>4 supergravity theories. They lead to quasiconformal realizations of split real forms of U-duality groups as a straightforward extension of the quaternionic real forms.Comment: Section 4 is split with the addition of a subsection on quadratic Casimir operators; references added; typos corrected. Latex file; 53 page