Semiclassical (Quantum Field Theory) and Quantum (String) de Sitter Regimes: New Results

We compute the quantum string entropy S_s(m, H) from the microscopic string density of states rho_s (m,H) of mass m in de Sitter space-time. We find for high m, a {\bf new} phase transition at the critical string temperature T_s= (1/2 pi k_B)L c^2/alpha', higher than the flat space (Hagedorn) temperature t_s. (L = c/H, the Hubble constant H acts at the transition as producing a smaller string constant alpha' and thus, a higher tension). T_s is the precise quantum dual of the semiclassical (QFT Hawking-Gibbons) de Sitter temperature T_sem = hbar c /(2\pi k_B L). We find a new formula for the full de Sitter entropy S_sem (H), as a function of the usual Bekenstein-Hawking entropy S_sem^(0)(H). For L << l_{Planck}, ie. for low H << c/l_Planck, S_{sem}^{(0)}(H) is the leading term, but for high H near c/l_Planck, a new phase transition operates and the whole entropy S_sem (H) is drastically different from the Bekenstein-Hawking entropy S_sem^(0)(H). We compute the string quantum emission cross section by a black hole in de Sitter (or asymptotically de Sitter) space-time (bhdS). For T_sem ~ bhdS << T_s, (early evaporation stage), it shows the QFT Hawking emission with temperature T_sem ~ bhdS, (semiclassical regime). For T_sem ~ bhdS near T_{s}, it exhibits a phase transition into a string de Sitter state of size L_s = l_s^2/L}, l_s= \sqrt{\hbar alpha'/c), and string de Sitter temperature T_s. Instead of featuring a single pole singularity in the temperature (Carlitz transition), it features a square root branch point (de Vega-Sanchez transition). New bounds on the black hole radius r_g emerge in the bhdS string regime: it can become r_g = L_s/2, or it can reach a more quantum value, r_g = 0.365 l_s.Comment: New original materia

Semiclassical (QFT) and Quantum (String) anti - de Sitter Regimes: New Results

We compute the quantum string entropy S_s(m, H) from the microscopic string density of states of mass m in Anti de Sitter space-time. For high m, (high Hm -->c/\alpha'), no phase transition occurs at the Anti de Sitter string temperature T_{s} which is higher than the flat space (Hagedorn) temperature t_{s}. (the Hubble constant H acts as producing a smaller string constant and thus, a higher tension). T_s is the precise quantum dual of the semiclassical (QFT) Anti de Sitter temperature scale . We compute the quantum string emission by a black hole in Anti de Sitter space-time (bhAdS). In the early evaporation stage, it shows the QFT Hawking emission with temperature T_{sem~bhAdS}, (semiclassical regime). For T_{sem~bhAdS}--> T_{s}, it exhibits a phase transition into a Anti de Sitter string state. New string bounds on the black hole emerge in the bhAdS string regime. We find a new formula for the full (quantum regime included) Anti de Sitter entropy S_{sem}, as a function of the usual Bekenstein-Hawking entropy S_{sem}^(0). For low H (semiclassical regime), S_{sem}^(0) is the leading term but for high H (quantum regime), no phase transition operates, in contrast to de Sitter space, and the entropy S_{sem} is very different from the Bekenstein-Hawking term S_{sem}^(0).Comment: Comments 26 pages; no figure

The Coastal Data Information Program, a Successful Federal, State and University Cooperation

International audienceThermal management and heat prediction are essential to improve the Li-ion battery operation life and performance, especially in Energy Storage System (ESS) for electric vehicles. Variation of cells temperatures of a battery pack can cause damage if not managed. In this paper, an electrochemical-thermal battery pack of three parallel-connected cylindrical Li-ion cells is modelled using COMSOL Multi-physics. The battery pack is cooled using air cooling approach with different inlet velocity to investigate its impact on the model temperature evolution , and the developed thermal model was then, charged/discharge at different temperatures to generate the essential data needed to model an electric-thermal model and identify its parameters in Matlab/Simulink software

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

Assessment of metal trace elements in the echinoderm Paracentrotus lividus from the North-Eastern coast of Algeria

The echinoderm sea urchin Paracentrotus lividus Lamarck, 1816 (Echinodermata, Echinoidea) is a good species to be used in environmental and toxicology research, in particular as a heavy metal bio-indicator. Our study’s objective is to evaluate the amounts of Zn, Pb, Fe, and Cu in sea urchin specimens collected from the coast of Skikda (Northeast Algeria) in order to validate the fact that sea urchins are good indicators of metal pollution and can be used effectively for environmental biomonitoring. To&nbsp;realize our objectives, three sampling sites were chosen based on suspected forms and sources of contamination. The main physicochemical parameters of the seawater were measured to determine their quality. 15 specimens of urchins in each station were obtained from exposed rocky surfaces and transported to the laboratory. Before dissection, the biometric parameters and the total wet weight were determined. The soft organs (gut and gonads) of individuals were separated and utilized to evaluate the levels of heavy metals. The condition index and metal indices were also determined. Our study confirmed that P. lividus may be considered a valuable bioindicator of heavy metal contamination in marine ecosystems. The results show that the amounts of heavy metals differed significantly between stations. Samples taken from the Larbi Ben M’hidi station showed greater amounts of Pb, Zn, and Cu. These amounts are above the recommended limits for fish and aquatic animals. Also, the heavy metals found in sea urchins vary depending on the physicochemical parameters, trace metals in the seawater, and the individual biometric parameters. These higher concentrations of metals in seawater and in P. lividus individuals at the Larbi Ben M’hidi station are largely caused by the construction of a massive oil industry complex and terminal with several refineries and petrochemical units near this station, as well as by a considerable amount of domestic wastewater. Finally, to avoid this metallic pollution risk, it is necessary that permanent controls be imposed as soon as possible. Urban and industrial wastes must be treated before being released, in the hope of reducing future metal concentrations

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

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

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

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