Coherent states for the q-deformed quantum mechanics on a circle

The q-deformed coherent states for a quantum particle on a circle are introduced and their properties investigated.Comment: 11 pages, 2 PostScript figure

First observational evidence of a North Madagascar Undercurrent

<i>In situ</i> observations reveal a southeastward-directed North Madagascar Undercurrent (NMUC) below and opposite to the equatorward-directed North Madagascar Current (NMC) off Cape Amber, at the northern tip of Madagascar. Results show an undercurrent hugging the continental slope with its core at 460 m depth and velocities over 0.7 m s-1. Its volume transport is estimated to be 3.1–3.8 Sv, depending on the velocity extrapolation methods used to fill in the data gaps near the slope (no-slip and full-slip, respectively). The thermohaline characteristics show a saltier and warmer NMUC, compared to the surrounding offshore waters, transporting mainly South Indian Central Water. Also, strong horizontal gradients of density are found in the NMUC domain. An inshore cell of coastal downwelling due to Ekman Transport toward the coast is identified, which can explain, at least in part, the strong baroclinic pressure gradients as well as the NMUC development and possible persistence

Coherent states for a particle on a sphere

The coherent states for a particle on a sphere are introduced. These states are labelled by points of the classical phase space, that is the position on the sphere and the angular momentum of a particle. As with the coherent states for a particle on a circle discussed in Kowalski K {\em et al} 1996 {\em J. Phys. A} {\bf 29} 4149, we deal with a deformation of the classical phase space related with quantum fluctuations. The expectation values of the position and the angular momentum in the coherent states are regarded as the best possible approximation of the classical phase space. The correctness of the introduced coherent states is illustrated by an example of the rotator.Comment: LaTeX, 16 pages, 2 figure

Nuevas citas de Eleutherodactylus Duméril y Bibron, 1841 (Anura, Leptodactylidae) para Bolivia

Five species of the genus Eleutherodactylus (Anura, Leptodactylidae) are reported from Bolivia for the first time: E. altamazonicus from Departments Pando and La Paz; E. carvalhoi from Cochabamba; and E. ockendeni, E. skydmainos and E. zimmermanae from Pando. New departmental records are provided for other species: E. cruralis for Department Pando, E. danae for Beni and La Paz, E. platydactylus for Beni, E. toftae for Pando and La Paz and E. ventrimarmoratus for La Paz. Currently, 25 species of Eleutherodactylus are known in Bolivia. The taxonomic status of some species remains uncertain, new species are being described and others are still to be discovered. Therefore, the actual number of Bolivian Eleutherodactylus species is still unknown.En este trabajo se publican los primeros registros de cinco especies del género Eleutherodactylus (Anura, Leptodactylidae) para Bolivia: E. altamazonicus en los Departamentos de Pando y La Paz; E. carvalhoi en Cochabamba; y E. ockendeni, E. skydmainos y E. zimmermanae en Pando. Además, se aportan las primeras citas de E. cruralis para el Departamento de Pando, de E. danae para Beni y La Paz, de E. platydactylus para Beni, de E. toftae para Pando y La Paz y de E. ventrimarmoratus para La Paz. La diversidad conocida de Eleutherodactylus en Bolivia es de 25 especies, aunque los problemas taxonómicos sin resolver, las especies en descripción y el alto número de especies aún no citadas que se considera probable encontrar, hacen que aún desconozcamos la verdadera diversidad de este género en Bolivia

Community Impacts of Prosopis Juliflora Invasion: Biogeographic and Congeneric Comparisons

We coordinated biogeographical comparisons of the impacts of an exotic invasive tree in its native and non-native ranges with a congeneric comparison in the non-native range. Prosopis juliflora is taxonomically complicated and with P. pallida forms the P. juliflora complex. Thus we sampled P. juliflora in its native Venezuela, and also located two field sites in Peru, the native range of Prosopis pallida. Canopies of Prosopis juliflora, a native of the New World but an invader in many other regions, had facilitative effects on the diversity of other species in its native Venezuela, and P. pallida had both negative and positive effects depending on the year, (overall neutral effects) in its native Peru. However, in India and Hawaii, USA, where P. juliflora is an aggressive invader, canopy effects were consistently and strongly negative on species richness. Prosopis cineraria, a native to India, had much weaker effects on species richness in India than P. juliflora. We carried out multiple congeneric comparisons between P. juliflora and P. cineraria, and found that soil from the rhizosphere of P. juliflora had higher extractable phosphorus, soluble salts and total phenolics than P. cineraria rhizosphere soils. Experimentally applied P. juliflora litter caused far greater mortality of native Indian species than litter from P. cineraria. Prosopis juliflora leaf leachate had neutral to negative effects on root growth of three common crop species of north-west India whereas P. cineraria leaf leachate had positive effects. Prosopis juliflora leaf leachate also had higher concentrations of total phenolics and L-tryptophan than P. cineraria, suggesting a potential allelopathic mechanism for the congeneric differences. Our results also suggest the possibility of regional evolutionary trajectories among competitors and that recent mixing of species from different trajectories has the potential to disrupt evolved interactions among native species

Quantum mechanics on a circle: Husimi phase space distributions and semiclassical coherent state propagators

We discuss some basic tools for an analysis of one-dimensionalquantum systems defined on a cyclic coordinate space. The basic features of the generalized coherent states, the complexifier coherent states are reviewed. These states are then used to define the corresponding (quasi)densities in phase space. The properties of these generalized Husimi distributions are discussed, in particular their zeros.Furthermore, the use of the complexifier coherent states for a semiclassical analysis is demonstrated by deriving a semiclassical coherent state propagator in phase space.Comment: 29 page

Análise do potencial de invasão do capim-annoni-2 sobre áreas do bioma Pampa no município de Aceguá-RS.

Tendo em conta os problemas que traz a invasão de espécies e especialmente o capim-anonni no Bioma Pampa, o objetivo do trabalho é utilizar o modelo de distribuição de espécies GARP para identificar ás áreas potenciais de invasão por essa espécie no município de Aceguá-RS e a influência da malha viária como variável no modelo, obtendo as variáveis ambientais e topográficas de imagens de sensores remotos