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Search Results: 1 - 10 of 611633 matches for " Martin Pépin A?na "
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Evaluation of the Opuntia dillenii as Natural Coagulant in Water Clarification: Case of Treatment of Highly Turbid Surface Water  [PDF]
Yéwêgnon Alima Esther Irma Nougbodé, Cokou Pascal Agbangnan, Alain Yaya Koudoro, Comlan Achille Dèdjiho, Martin Pépin Ana, Daouda Mama, Dominique Codjo Koko Sohounhloué
Journal of Water Resource and Protection (JWARP) , 2013, DOI: 10.4236/jwarp.2013.512133

This study was performed in laboratory scale and consisted of the using of aqueous Opuntia dillenii solution for the clarification of very turbid surface water (Turbidities varying between 186 NTU and 418 NTU). This plant from Cactaceae family was used as a natural coagulant for the different clarification tests. The preliminary phytochemical Screening of the powder of this plant showed that it contains tanins, saponins and mucilages. Flocculation and coagulation tests showed that Opuntia dillenii can be used in highly turbid water treatment. The removal efficiency varied from 89% to 93% for the turbidity and suspended solids, and from 4% to 15% for the obvious color in water when we used the optimum values of this natural coagulant (1 mL to 10 mL). The successive addition of this natural coagulant and the lime, gave a better elimination of turbidity and suspended solids, and a good reduction for the color. The removal efficiency of the turbidity and suspended solids became more than 95% and the one of the color between 67% and 94%.

The Human Gonadotropin Releasing Hormone Type I Receptor Is a Functional Intracellular GPCR Expressed on the Nuclear Membrane
Michelle Re,Macarena Pampillo,Martin Savard,Céléna Dubuc,Craig A. McArdle,Robert P. Millar,P. Michael Conn,Fernand Gobeil Jr,Moshmi Bhattacharya,Andy V. Babwah
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0011489
Abstract: The mammalian type I gonadotropin releasing hormone receptor (GnRH-R) is a structurally unique G protein-coupled receptor (GPCR) that lacks cytoplasmic tail sequences and displays inefficient plasma membrane expression (PME). Compared to its murine counterparts, the primate type I receptor is inefficiently folded and retained in the endoplasmic reticulum (ER) leading to a further reduction in PME. The decrease in PME and concomitant increase in intracellular localization of the mammalian GnRH-RI led us to characterize the spatial distribution of the human and mouse GnRH receptors in two human cell lines, HEK 293 and HTR-8/SVneo. In both human cell lines we found the receptors were expressed in the cytoplasm and were associated with the ER and nuclear membrane. A molecular analysis of the receptor protein sequence led us to identify a putative monopartite nuclear localization sequence (NLS) in the first intracellular loop of GnRH-RI. Surprisingly, however, neither the deletion of the NLS nor the addition of the Xenopus GnRH-R cytoplasmic tail sequences to the human receptor altered its spatial distribution. Finally, we demonstrate that GnRH treatment of nuclei isolated from HEK 293 cells expressing exogenous GnRH-RI triggers a significant increase in the acetylation and phosphorylation of histone H3, thereby revealing that the nuclear-localized receptor is functional. Based on our findings, we conclude that the mammalian GnRH-RI is an intracellular GPCR that is expressed on the nuclear membrane. This major and novel discovery causes us to reassess the signaling potential of this physiologically and clinically important receptor.
Winery wastewater treatment monitored using planted wetland common reed bed
Martin Pépin AINA,Justine DEGUENON,Julien ADOUNKPE,Daouda MAMA
International Journal of Engineering Science and Technology , 2012,
Abstract: Agro businesses use a great amount of water in the production processes. Consequently they are very concerned with wastewater treatment before any discharge. Wastewater from agribusinesses contains elevated concentration of organic matters and nitrogen. Winery wastewater gets high salinity, and depending on the daily, monthly or yearly production, it is characterized by a very variable flow. Physico-chemical ways of wastewater treatment use chemicals that can turn out be to pollutants or which can generate hazardous byproducts whereas biological treatment is more environmentally friendly by fitting into the landscape and not producing any potentially dangerous products. The constructed wetland with reed beds is the only biological treatment which can be both ecologically and costly efficient. Therefore an experimental constructed wetlandwith vertical flow reed beds was built to treat wastewater from BARDET’s vinery in France. The experience was run for 7 weeks. For average input concentrations of: TSS (335,4 mg/L), TKN (26,3 mg/L) and TP (6 mg/L)the output concentrations were the following: TSS (43,2 mg/L), TKN (11,1 mg/L) and TP (2,1 mg/L) . The average removal rates were: TSS (86,5%), TKN (61,8%) and TP (62,9%). The treated water had concentrations that were in line with the regulation set forth in the 02/02/98 decree which set the output concentration in a river at: TSS (100 mg/L), GN (30 mg/L) and TP (10 mg/L).
Optimal equilibria of the best shot game
L. Dall'Asta,P. Pin,A. Ramezanpour
Physics , 2010,
Abstract: We consider any network environment in which the "best shot game" is played. This is the case where the possible actions are only two for every node (0 and 1), and the best response for a node is 1 if and only if all her neighbors play 0. A natural application of the model is one in which the action 1 is the purchase of a good, which is locally a public good, in the sense that it will be available also to neighbors. This game typically exhibits a great multiplicity of equilibria. Imagine a social planner whose scope is to find an optimal equilibrium, i.e. one in which the number of nodes playing 1 is minimal. To find such an equilibrium is a very hard task for any non-trivial network architecture. We propose an implementable mechanism that, in the limit of infinite time, reaches an optimal equilibrium, even if this equilibrium and even the network structure is unknown to the social planner.
Statistical Mechanics of maximal independent sets
L. Dall'Asta,P. Pin,A. Ramezanpour
Physics , 2009, DOI: 10.1103/PhysRevE.80.061136
Abstract: The graph theoretic concept of maximal independent set arises in several practical problems in computer science as well as in game theory. A maximal independent set is defined by the set of occupied nodes that satisfy some packing and covering constraints. It is known that finding minimum and maximum-density maximal independent sets are hard optimization problems. In this paper, we use cavity method of statistical physics and Monte Carlo simulations to study the corresponding constraint satisfaction problem on random graphs. We obtain the entropy of maximal independent sets within the replica symmetric and one-step replica symmetry breaking frameworks, shedding light on the metric structure of the landscape of solutions and suggesting a class of possible algorithms. This is of particular relevance for the application to the study of strategic interactions in social and economic networks, where maximal independent sets correspond to pure Nash equilibria of a graphical game of public goods allocation.
Order from Disorder: Non Magnetic Impurities in the Spin-gap Phase of the Cuprates
Catherine Pépin,Patrick A. Lee
Physics , 1998, DOI: 10.1103/PhysRevLett.81.2779
Abstract: We solve the problem of $N$ non magnetic impurities in the staggered flux phase of the Heisenberg model which we assume to be a good mean-field approximation for the spin-gap phase of the cuprates. The density of states is evaluated exactly in the unitary limit and is porportional to $1/\left (\omega \ln^2(|\omega|/D))$, in analogy with the 1D case of doped spin-Peierls and two-leg ladders compounds. We argue that the system exhibits a quasi long-range order at T=0 with instantaneous spin-spin correlations decreasing as $n_i/ \ln^2\left (n_i R_{ij})$ for large distances $R_{ij}$ and we predict enhanced low energy fluctuations in Neutron Scattering.
Coriorretinopatía serosa central en la distrofia viteliforme foveomacular del adulto Central serous corioretinopathy in adult onset foveomacular vitelliform dystrophy
J. Pinós,A. Sabater,C. Navarro,P. Carbonell
Archivos de la Sociedad Espa?ola de Oftalmología , 2008,
Abstract: Caso Clínico: Se presenta el caso clínico de un varón de 30 a os con una distrofia foveomacular viteliforme del adulto bilateral simétrica, que de forma simultánea desarrolla una coriorretinopatía central serosa (CRCS) y en el que se aprecia la coexistencia de múltiples puntos blancos en la proximidad de las arcadas vasculares temporales. La angiografía fluoresceínica demuestra la alteración mixta de ambos tipos de fotorreceptores, así como la lesión aguda de la CRCS en el polo posterior OI. Discusión: La distrofia foveomacular del adulto es una alteración hereditaria del polo posterior que no suele evolucionar con complicaciones agudas. La aparición de una coriorretinopatía central no es habitual. Case report: The clinical case of a 30 year-old male patient with a bilateral and symmetric adult-onset foveomacular vitelliform dystrophy is presented. The simultaneous onset of a central serous chorioretinopathy (CSCR) with multiple white dots in the proximity of the temporal vascular arcades is documented. Fluorescein angiography showed a combined alteration of both types of photoreceptors, and the acute lesion of the CSCR at the posterior pole of the eye. Discussion: Adult-Onset Foveomacular Vitelliform Dystrophy is a hereditary condition which results in an alteration of the posterior pole of the eye, but is not usually associated with any acute complications. The onset of a CSCR, as seen in this case, is unusual.
Luttinger-Ward functional approach in the Eliashberg framework : A systematic derivation of scaling for thermodynamics near a quantum critical point
A. Benlagra,K. -S. Kim,C. Pépin
Physics , 2009, DOI: 10.1088/0953-8984/23/14/145601
Abstract: Scaling expressions for the free energy are derived, using the Luttinger-Ward (LW) functional approach in the Eliashberg framework, for two different models of quantum critical point (QCP). First, we consider the spin-density-wave (SDW) model for which the effective theory is the Hertz-Moriya-Millis (HMM) theory, describing the interaction between itinerant electrons and collective spin fluctuations. The dynamic of the latter are described by a dynamical exponent $z$ depending on the nature of the transition. Second, we consider the Kondo breakdown model for QCP's, one possible scenario for heavy-fermion quantum transitions, for which the effective theory is given by a gauge theory in terms of conduction electrons, spinons for localized spins, holons for hybridization fluctuations, and gauge bosons for collective spin excitations. For both models, we construct the thermodynamic potential, in the whole phase diagram, including all kinds of self-energy corrections in a self-consistent way, at the one loop level. We show how Eliashberg framework emerges at this level and use the resulting Eliashberg equations to simplify the LW expression for free energy . it is found that collective boson excitations play a central role. The scaling expression for the singular part of the free energy near the Kondo breakdown QCP is characterized by two length scales : one is the correlation length for hybridization fluctuations, and the other is that for gauge fluctuations, analogous to the penetration depth in superconductors.
Grüneisen ratio at the Kondo breakdown quantum critical point
K. -S. Kim,A. Benlagra,C. Pépin
Physics , 2008, DOI: 10.1103/PhysRevLett.101.246403
Abstract: We show that the scenario of multi-scale Kondo breakdown quantum critical point (QCP) gives rise to a divergent Gr\"uneisen ratio with an anomalous exponent 0.7. In particular, we fit the experimental data of $YbRh_{2}(Si_{0.95}Ge_{0.05})_{2}$ for specific heat, thermal expansion, and Gr\"uneisen ratio based on our simple analytic expressions. A reasonable agreement between the experiment and theory is found for the temperature range between 0.4 K and 10 K. We discuss how the Gr\"uneisen ratio is a key measurement to discriminate between the Kondo breakdown and spin-density wave theories.
Modulated Spin Liquid and Magnetic Order from a Kondo-Heisenberg model applied to $URu_{2}Si_{2}$
X. Montiel,S. Burdin,C. Pépin,A. Ferraz
Physics , 2013, DOI: 10.1103/PhysRevB.90.045125
Abstract: Within the framework of the Kondo-Heisenberg model, we analyse the effect of charge fluctuation on the modulated spin liquid (MSL) and antiferromagnetic (AF) orders which were established in a previous publication. We discuss the emergence of two quantum critical lines separating the coexisting Kondo-MSL and Kondo-MSL-AF phases. The various order parameters of the system possess a characteristic signature observable on the electronic band structure of each of the phases. We calculate that the MSL order is indeed a possible explanation of the hidden order phase of $URu_{2}Si_{2}$ heavy fermion compound. Our model produces results in qualitative agreement with the experimental (T,P) phase diagram and the two gap openings in the system and quantitative agreement with the entropy and Sommerfeld coefficient evolution.
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