Lexicography in Gabon : a survey

This paper traces the historical development of lexicography in Gabon. Gabon, like most African countries, is multilingual. The recent inventories of languages spoken in Gabon are those established by Jacquot (1978) and Kwenzi-Mikala (1998). According to Kwenzi-Mikala (1997), there are 62 speech forms divided into 10 language groups or language-units in Gabon. These speech forms co-exist with French, the official language. In fact, in article 2 of paragraph 8 of the revised Constitution of 1994 the following can be read: "The Gabonese Republic adopts French as the official language. Furthermore, she endeavours to protect and promote the national languages." This constitutional arrangement naturally makes French the language used in education, administration and the media. The survey of lexicography in Gabon that is presented here includes the linguistic situation in and the language policy of Gabon, the lexicographic survey itself, as well as the lexicographic needs of the different speech forms (including languages and dialects). Initially, the pioneers of Gabonese lexicography were missionaries or colonial administrators. Very little was done in this field by the Gabonese themselves. Although credit is to be given to these early works, there are a number of shortcomings regarding the linguistic as well as the metalexicographic contents of dictionaries and lexicons produced during this period. In fact, the main weak point of those studies was the lack of tones in the written transcription of oral productions and orthographic problems. Furthermore, in those contributions, the theory of lexicography is largely unknown and lexico-graphic works are hardly ever based on authentic data corpora of the languages being described.Le présent article retrace l'histoire de la discipline lexicographique au Gabon. Comme la plupart des pays africains, le Gabon est un état multilingue. Les classifications établient par Jacquot (1978) et Kwenzi-Mikala (1998) sont souvent citées comme les travaux d'inventaire les plus récents sur les parlers gabonais. Selon Kwenzi-Mikala (1997), le Gabon compte 62 parlers reparties en 10 unités-langues. Les dits parlers cohabitent avec le français qui faut-il le rappeler jouit d'un statut particulier. En effet, à l'article 2 du paragraphe 8 de la Loi fondamentale révisée de 1994, on peut lire ceci: «La République gabonaise adopte le français comme langue officielle. En outre, elle s'engage à protéger et à promovoir les langues nationales». Cette disposition constitutionnelle fait naturellement du français le véhicule et la matière de l'instruction, la langue de l'administration et celle des médias. L'état des lieux de la lexicographie au Gabon présenté ici prend en compte la situation et la politique linguistique au Gabon, l'état des connaissances lexicographiques à proprement parler ainsi que les besions lexicographiques des différents parlers au regard de ce qui existe déjà. Les premiers travaux à caractère lexicographique ont été réalisés essentiellement par les missionnaires et les administrateurs coloniaux. Très peu de gabonais étaient engagés dans la confection des dictionnaires et lexiques à cette époque pionnière. Enfin, il convient de souligner que le principal talon d'Achille de ces travaux de la première heure est à la fois linguistique et métalexicographi-que. En effet, la majorité de ces travaux ne prennent pas en compte le système tonal des parlers décrits et s'inscrivent rarement dans un cadre théorique défini. Enfin, ils souffrent de nombreuses insuffisances orthographiques et sont rarement basés sur des corpus linguistiques

Ultra-Fast Relaxation, Decoherence and Localization of Photoexcited States in π\pi-Conjugated Polymers: A TEBD Study

The exciton relaxation dynamics of photoexcited electronic states in poly($p$-phenylenevinylene) (PPV) are theoretically investigated within a coarse-grained model, in which both the exciton and nuclear degrees of freedom are treated quantum mechanically. The Frenkel-Holstein Hamiltonian is used to describe the strong exciton-phonon coupling present in the system, while external damping of the internal nuclear degrees of freedom are accounted for by a Lindblad master equation. Numerically, the dynamics are computed using the time evolving block decimation (TEBD) and quantum jump trajectory techniques. The values of the model parameters physically relevant to polymer systems naturally lead to a separation of time scales, with the ultra-fast dynamics corresponding to energy transfer from the exciton to the internal phonon modes (i.e., the C-C bond oscillations), while the longer time dynamics correspond to damping of these phonon modes by the external dissipation. Associated with these time scales, we investigate the following processes that are indicative of the system relaxing onto the emissive chromophores of the polymer: 1) Exciton-polaron formation occurs on an ultra-fast time scale, with the associated exciton-phonon correlations present within half a vibrational time period of the C-C bond oscillations. 2) Exciton decoherence is driven by the decay in the vibrational overlaps associated with exciton-polaron formation, occurring on the same time scale. 3) Exciton density localization is driven by the external dissipation, arising from `wavefunction collapse' occurring as a result of the system-environment interactions. Finally, we show how fluorescence anisotropy measurements can be used to investigate the exciton decoherence process during the relaxation dynamics.Comment: 16 pages, 15 figure

Ultracold atoms in an optical lattice with dynamically variable periodicity

The use of a dynamic "accordion" lattice with ultracold atoms is demonstrated. Ultracold atoms of $^{87}$Rb are trapped in a two-dimensional optical lattice, and the spacing of the lattice is then increased in both directions from 2.2 to 5.5 microns. Atoms remain bound for expansion times as short as a few milliseconds, and the experimentally measured minimum ramp time is found to agree well with numerical calculations. This technique allows an experiment such as quantum simulations to be performed with a lattice spacing smaller than the resolution limit of the imaging system, while allowing imaging of the atoms at individual lattice sites by subsequent expansion of the optical lattice.Comment: 4 pages, 3 figures. Minor changes made and references update

Observation of vortex nucleation in a rotating two-dimensional lattice of Bose-Einstein condensates

We report the observation of vortex nucleation in a rotating optical lattice. A 87Rb Bose-Einstein condensate was loaded into a static two-dimensional lattice and the rotation frequency of the lattice was then increased from zero. We studied how vortex nucleation depended on optical lattice depth and rotation frequency. For deep lattices above the chemical potential of the condensate we observed a linear dependence of the number of vortices created with the rotation frequency,even below the thermodynamic critical frequency required for vortex nucleation. At these lattice depths the system formed an array of Josephson-coupled condensates. The effective magnetic field produced by rotation introduced characteristic relative phases between neighbouring condensates, such that vortices were observed upon ramping down the lattice depth and recombining the condensates.Comment: 4 pages, 4 figures, accepted for publication in Phys. Rev. Let

Heat transport in the XXZXXZ spin chain: from ballistic to diffusive regimes and dephasing enhancement

In this work we study the heat transport in an XXZ spin-1/2 Heisenberg chain with homogeneous magnetic field, incoherently driven out of equilibrium by reservoirs at the boundaries. We focus on the effect of bulk dephasing (energy-dissipative) processes in different parameter regimes of the system. The non-equilibrium steady state of the chain is obtained by simulating its evolution under the corresponding Lindblad master equation, using the time evolving block decimation method. In the absence of dephasing, the heat transport is ballistic for weak interactions, while being diffusive in the strongly-interacting regime, as evidenced by the heat-current scaling with the system size. When bulk dephasing takes place in the system, diffusive transport is induced in the weakly-interacting regime, with the heat current monotonically decreasing with the dephasing rate. In contrast, in the strongly-interacting regime, the heat current can be significantly enhanced by dephasing for systems of small size

Topological pumping of photons in nonlinear resonator arrays

We show how to implement topological or Thouless pumping of interacting photons in one dimensional nonlinear resonator arrays, by simply modulating the frequency of the resonators periodically in space and time. The interplay between interactions and the adiabatic modulations enables robust transport of Fock states with few photons per site. We analyze the transport mechanism via an effective analytic model and study its topological properties and its protection to noise. We conclude by a detailed study of an implementation with existing circuit QED architectures.Comment: 5 pages, 4 figures, and Supplemental Material. Comments are welcom

Environmental Consequences of Solar Energy Development and Other Sources of Energy

In recent years, scientists are increasingly raising the question of the huge impact of solar energy on the ecology of our world. This study attempts to unveil the relationship between the development of solar energy and the threat of growth of environmental problems. Thus, the stream of solar energy simply has to be taken under the control of people and used as much as possible, but with the preservation of the unique earth's climate. At the moment, it is no secret that carbon resources are being depleted very rapidly, and if the search for alternative sources of energy in the near future will not succeed, then the prospects for our civilization are absolutely small. So, among the possible successors that are able to pick up the baton of traditional energy, the most attractive among alternative energy sources is solar energy, which is considered environmentally friendly. Keywords: Solar energy, energy, ecology, ecological problems, climate, environment

Aero-Thermodynamics Optimization of Re-Entry Capsule in the Slip Flow Regime

We carry out numerical simulations to optimize the re- entry capsule configurations based on aero-thermodynamic properties such as drag, pressure and heat load. The open source software OpenFOAM is used with the compress- ible computational fluid dynamics (CFD) solver rhoCen- tralFoam. CFD solver is implemented with the first-order Maxwell’s velocity slip and the Smoluchowski temperature jump boundary conditions. We report results for different altitudes and Mach numbers with varying second cone an- gle and bluntness of the re-entry capsule. It is noted that the heat loads are greatly reduced by changing the capsule con- figuration from single to bi-cone. With increasing second cone angle heat loads are enhanced, but the average drag and pressure coefficients found to be least sensitive. How- ever, with increase in bluntness the average value of heat load decrease slightly and the peak value significantly, while drag values exhibit contrasting behaviour

On the Discrimination Power of Dynamic Features for Online Signature

The mobile market has taken huge leap in the last two decades, re-defining the rules of communication, networking, socializing and transactions among individuals and organizations. Authentication based on verification of signature on mobile devices, is slowly gaining popularity. Most online signature verification algorithms focus on computing the global Equal Error Rate across all users for a dataset. In this work, contrary to such a representation, it is shown that there are user-specific differences on the combined features and user-specific differences on each feature of the Equal Error Rate(EER) values. The experiments to test the hypothesis is carried out on the two publicly available dataset using the dynamic time warping algorithm. From the experiments, it is observed that for the MCYT-100 dataset, which yields an overall EER of 0.08, the range of user-specific EER is between 0 and 0.27