Newton algorithm for Hamiltonian characterization in quantum control

We propose a Newton algorithm to characterize the Hamiltonian of a quantum system interacting with a given laser field. The algorithm is based on the assumption that the evolution operator of the system is perfectly known at a fixed time. The computational scheme uses the Crank-Nicholson approximation to explicitly determine the derivatives of the propagator with respect to the Hamiltonians of the system. In order to globalize this algorithm, we use a continuation method that improves its convergence properties. This technique is applied to a two-level quantum system and to a molecular one with a double-well potential. The numerical tests show that accurate estimates of the unknown parameters are obtained in some cases. We discuss the numerical limits of the algorithm in terms of basin of convergence and non uniqueness of the solution.Comment: 18 pages, 7 figure

Elimination of Potential Pathogenic Microorganisms in Sewage Sludge Using Electron Beam Irradiation

Microbiological analyses on municipal sewage sludge sample treated in a pilot plant process utilizing an electron accelerator with a beam energy of 3 MeV were conducted as a way to show the potential of this technology to decontaminate sludge containing 15% solids. Bacterial counts including total heterotrophic bacterial, total coliform, and fecal coliform counts were performed on sewage sludge samples pre- and postirradiation with the electron beam at doses ranging between 2.7 and 30.7 kGy. At each irradiation dose, bacterial and Ascaris ova counts and survival were measured in triplicate as colony forming units (CFUs) per milliliter (ml) of sewage sludge. Experimental results obtained revealed that a dose of 6.7 kGy is enough to reduce bacterial load to consider the treated sewage sludge safe for both the environment and human according to the Environmental Protection Agency standards. However, a dose of 25.7 kGy was needed to reduce the concentration of Ascaris ova at levels deemed safe for land applications. This study also showed that electron beam treatment is less energy consuming with shorter processing times than conventional techniques used to decontaminate sludge. Taken altogether, these observations open new avenues for large urban agglomerations to save money on sewage sludge treatment

Tectonique salifère et déformation gravitaire de la marge passive sud-gabonaise de l'Albien au Turonien (secteur de Mayumba) Salt tectonic and thin-skinned deformation in south Gabon passive margin during the Albian-Turonian (Mayumba area).

International audienceL'observation de données sismiques de bonne qualité relatives à la marge passive sud-gabonaise montre : 1) les structures extensives, compressives et inversives albo-turoniennes, associées à la tectonique gravitaire au-dessus du niveau salifère Ezanga (Aptien supérieur). D'est en ouest, ces structures synsédimentaires, d'échelle kilo-métrique, sont en blocs basculés, en anticlinaux, en roll over, en " carapace de tortue ", de nouveau en plis et failles inverses, et enfin en langues de sel déversées vers l'ouest. 2) l'influence du niveau salifère sur la structuration gravitaire ; 3) l'héritage passif syn-rift au niveau des zones hautes anté-salifères qui favorisent la terminaison du sel en biseau et la caractérisation de deux domaines structuraux : l'un interne, peu subsident, où se développent des structures de faible espacement et l'autre externe, très subsident, marqué par des structures de grand espacement. Observation of excellent quality seismic data from the passive margin of the South Gabon basin margin shows: i) Structures associated with thin-skinned deformation of the albo-turonian platform over the Ezanga salt formation (Upper Aptian). The study domain shows a series of Albian-Turonian kilometric extensional, compressional and inver-sional syn-sedimentary structures. From east to west, the domain features tilted blocs, fold and anticline structures, roll-over and turtleback extensive structures, and again fold and inverse faults compressional structures and west-wards salt overhangs. ii) The role of the salt layer in the structural thin-skinned distribution. iii) The high topographic syn-rift control by exhibiting the bevelled salt ending and the characterisation of two structural domains: an internal domain characterised by low subsidence and short extensional structures, and an external domain characterised by high subsidence and long extensional structures

New, Highly Accurate Propagator for the Linear and Nonlinear Schr\"odinger Equation

A propagation method for the time dependent Schr\"odinger equation was studied leading to a general scheme of solving ode type equations. Standard space discretization of time-dependent pde's usually results in system of ode's of the form u_t -Gu = s where G is a operator (matrix) and u is a time-dependent solution vector. Highly accurate methods, based on polynomial approximation of a modified exponential evolution operator, had been developed already for this type of problems where G is a linear, time independent matrix and s is a constant vector. In this paper we will describe a new algorithm for the more general case where s is a time-dependent r.h.s vector. An iterative version of the new algorithm can be applied to the general case where G depends on t or u. Numerical results for Schr\"odinger equation with time-dependent potential and to non-linear Schr\"odinger equation will be presented.Comment: 14 page

Déformation et métamorphisme dans la partie centrale de la chaine de Ngovayang (Sud-Cameroun)

La chaine de Ngovayang fait partie des formations tectoniques majeures de l’unité du Nyong au sud du Cameroun. Son histoire tectonique est caractérisée par trois phases de déformation qui se sont développées de l’archéen au début du panafricain. La phase D1 est responsable du plissement P1 et de la foliation S1. La phase D2, considérée comme phase majeure de déformation, est syntectonique. Elle a mis en place une schistosité S2 globalement NE-SW à pendage NW, plan axial des plis P2 et porteuse d’une linéation L2. Quant à la déformation D3, elle est assez tardive et discontinue. La principale empreinte métamorphique est liée à la phase de déformation D2, caractérisée par un métamorphisme de haut degré (faciès des amphibolites supérieures au faciès des granulites).Mots-clés : phase de déformation, chaine de Ngovayang, tectonique, métamorphisme, Nyong, Cameroun.Deformation and metamorphism in the central part of the Ngovayang chain (SouthCameroon)The Ngovayang chain forms part of the major tectonic unit of the Nyong Series in southern Cameroon. Its tectonic history is characterized by three phases of deformation that developed during the Archean to early Panafrican period. The D1 phase is responsible for the S1 foliation and the P1 fold. Phase D2, considered as the major phase of deformation, is syntectonic. It generated an S2 schistosity with a general NE-SW direction and NW dip. The S2 schistosity has a fold axial plane P2 and bears a lineation L2. The D3 deformation on the other hand is post tectonic and discontinuous. The main metamorphic imprint is related to the D2 deformation phase, characterized by a high grade of metamorphism (upper amphibolites to granulite facies).Keywords : deformation phase, Ngovayang chain, tectonic, metamorphism, Nyong, Cameroon

Carrying Asymptomatic Malaria In Ouéllé Locality, And Surrounding Villages, In Southeastern Gabon: An Epidemiological Analysis, In Rural Central Africa

Background: Malaria remains a major public health problem in sub-Saharan Africa, and particularly in Gabon. In an epidemiological analysis in a rural area, the present study assessed asymptomatic malaria carriage in Ouéllé, and surrounding villages, in South-eastern Gabon: an epidemiological analysis, in a rural area of central Africa. Patients and method: This prospective, cross-sectional study was conducted from June 26 to 28, 2023. The sociodemographic characteristics of the participants were obtained. A small portion of blood collected by finger prick from each participant was used for qualitative detection of malaria-causing Plasmodium infection, using a Malaria Test MeriScreenTM Pf/PAN Ag lateral flow immunochromatographic assay. Results of analysis by R software version 4.0.3, were considered significant at p≤0.05.Results: Of the 321 people registered for the present study, 97  (30.22%) (95% CI: 0.25 - 0.36) (n=97), tested positive for malaria, compared with 224 (69.78%) ((95% CI: 0.64 - 0.75) (n=224). While a univariate analysis of the prevalence of malaria carriage according to gender showed no statistically significant association between the variables p=0.56, a univariate analysis of the prevalence of malaria carriage according to age group indicated that only participants aged between 28 and 57 (OR =0.17; 95% CI: [0.04 - 0.73] p=0. 007*), and according to each locality, the analysis showed that participants from Mvengué (OR =0.17; CI 95% : [0.04 - 0.73] p=0.007*), Djoutou (OR =0.17; CI 95% : [0.04 - 0.73] p=0. 007*), and Mouyabi (OR =0.17; 95% CI: [0.04 - 0.73] p=0.007*), were statistically susceptible to malaria were significantly associated with malaria carriage in the present study.Conclusion: These results, which indicate the persistence of asymptomatic malaria in Ouéllé and surrounding villages, call on Gabon's health authorities to redouble their efforts to combat malaria throughout the country