Sur les limites d'application du modèle de Stephens

Les conséquences de l'hypothèse de la conservation de j dans le modèle de Stephens sont analysées. Les conditions de l'applicabilité de cette hypothèse dans le cas des sous-couches isolées (l'extension est faite à N = 4 et N = 3) sont discutées et des explications en sont données. Dans les autres cas, un traitement exact des états propres du mouvement intrinsèque permet néanmoins l'extension du modèle de Stephens sans élargissement de la base de diagonalisation

Self-consistent collective subspaces and diabatic/adiabatic motion in nuclei

We discuss the application of a theory of large-amplitude collective motion to a simple model mimicking the pairing-plus-quadrupole model of nuclear physics.Comment: 4 pages, RevTex using graphicx.sty, 1 postscript figures included. Talk presented at Conference on "Nuclear structure at the extremes" (June 17 - 19, 1998, Lewes, UK

Parametrization of the octupole degrees of freedom

A simple parametrization for the octupole collective variables is proposed and the symmetries of the wave functions are discussed in terms of the solutions corresponding to the vibrational limit. [PACS: 21.60Ev, 21.60.Fw, 21.10.Re]Comment: 14 page

Multi-Phonon γ\gamma-Vibrational Bands and the Triaxial Projected Shell Model

We present a fully quantum-mechanical, microscopic, unified treatment of ground-state band and multi-phonon $\gamma$-vibrational bands using shell model diagonalization with the triaxial projected shell model. The results agree very well with data on the g- and $\gamma$-band spectra in $^{156-170}$Er, as well as with recently measured $4^+$ 2-phonon $\gamma$-bandhead energies in $^{166}$Er and $^{168}$Er. Multi-phonon $\gamma$-excitation energies are predicted.Comment: 4 pages, 4 figures, submitted to Phys. Lett.

HONGOS ENTOMOPATÓGENOS ASOCIADOS A INSECTOS RECOLECTADOS EN PLANTACIONES DE CAFÉ EN EL OESTE DE PANAMÁ

This study was carried out in order to determine the diversity of native entomopathogenic fungi associated to insects present in coffee plantations in Boquete (without the presence of Hipothenemus hampei Ferrari). Fieldwork was conducted between October and November 2005. Insects were collected with the symptoms of entomopathogenic fungi attack and were isolated and identified. A total of 33 fungal cultures were obtained from the isolation of mycelia present in samples of insects collected in the field. The cultures correspond to 7 species in 5 genera of pathogenic fungi: Acremonium charticola, A. crassum, Beauveria bassiana, B. brongniartii, Fusarium oxysporum, Lecanicillium tenuipes, Metarhizium anisopliae and Torrubiella tenuis, which were found on insects of the orders Dermaptera and Hemiptera. Of these species, only Beauveria and Acremonium have been documented in other studies as natural enemies of H. hampei. T. tenuis was the only teleomorph found infesting scale insects.  Este estudio se realizó con la finalidad de determinar la diversidad de hongos entomopatógenos nativos asociados a insectos presentes en plantaciones de café en Boquete (sin la presencia de Hypothenemus hampei Ferrari).  El trabajo de campo se realizó entre octubre y noviembre de 2005. Se recolectaron insectos con la sintomatología del ataque de hongos entomopatógenos y se aislaron e identificaron. Un total de 33 cultivos de hongos se obtuvieron del aislamiento de micelio presente en las muestras de insectos. Los cultivos corresponden a siete especies en cinco géneros de hongos patógenos: Acremonium charticola, A. crassum, Beauveria bassiana, B. brongniartii, Fusarium oxysporum, Lecanicillium tenuipes, Metarhizium anisopliae y Torrubiella tenuis, los cuales se encontraron en insectos de los órdenes Dermáptera y Hemiptera. De éstas especies, solo Acremonium y Beauveria han sido documentadas en otros estudios como enemigos naturales de H. hampei. Torrubiella tenuis fue el único teleomorfo encontrado parasitando insectos escamas

An overview of the higher level classification of Pucciniomycotina based on combined analyses of nuclear large and small subunit rDNA sequences

Mycologia, Vol. 98, nº6In this study we provide a phylogenetically based introduction to the classes and orders of Pucciniomycotina (5Urediniomycetes), one of three subphyla of Basidiomycota. More than 8000 species of Pucciniomycotina have been described including putative saprotrophs and parasites of plants, animals and fungi. The overwhelming majority of these(,90%) belong to a single order of obligate plant pathogens, the Pucciniales (5Uredinales), or rust fungi. We have assembled a dataset of previously published and newly generated sequence data from two nuclear rDNA genes (large subunit and small subunit) including exemplars from all known major groups in order to test hypotheses about evolutionary relationships among the Pucciniomycotina. The utility of combining nuc-lsu sequences spanning the entire D1-D3 region with complete nuc-ssu sequences for resolution and support of nodes is discussed. Our study confirms Pucciniomycotina as a monophyletic group of Basidiomycota. In total our results support eight major clades ranked as classes (Agaricostilbomycetes, Atractiellomycetes, Classiculomycetes,Cryptomycocolacomycetes,Cystobasidiomycetes, Microbotryomycetes,Mixiomycetes and Pucciniomycetes) and 18 orders

AxPcoords & parallel AxParafit: statistical co-phylogenetic analyses on thousands of taxa

Background Current tools for Co-phylogenetic analyses are not able to cope with the continuous accumulation of phylogenetic data. The sophisticated statistical test for host-parasite co-phylogenetic analyses implemented in Parafit does not allow it to handle large datasets in reasonable times. The Parafit and DistPCoA programs are the by far most compute-intensive components of the Parafit analysis pipeline. We present AxParafit and AxPcoords (Ax stands for Accelerated) which are highly optimized versions of Parafit and DistPCoA respectively. Results Both programs have been entirely re-written in C. Via optimization of the algorithm and the C code as well as integration of highly tuned BLAS and LAPACK methods AxParafit runs 5–61 times faster than Parafit with a lower memory footprint (up to 35% reduction) while the performance benefit increases with growing dataset size. The MPI-based parallel implementation of AxParafit shows good scalability on up to 128 processors, even on medium-sized datasets. The parallel analysis with AxParafit on 128 CPUs for a medium-sized dataset with an 512 by 512 association matrix is more than 1,200/128 times faster per processor than the sequential Parafit run. AxPcoords is 8–26 times faster than DistPCoA and numerically stable on large datasets. We outline the substantial benefits of using parallel AxParafit by example of a large-scale empirical study on smut fungi and their host plants. To the best of our knowledge, this study represents the largest co-phylogenetic analysis to date. Conclusion The highly efficient AxPcoords and AxParafit programs allow for large-scale co-phylogenetic analyses on several thousands of taxa for the first time. In addition, AxParafit and AxPcoords have been integrated into the easy-to-use CopyCat tool

Internet of Things for Sustainable Forestry

Forests and grasslands play an important role in water and air purification, prevention of the soil erosion, and in provision of habitat to wildlife. Internet of Things has a tremendous potential to play a vital role in the forest ecosystem management and stability. The conservation of species and habitats, timber production, prevention of forest soil degradation, forest fire prediction, mitigation, and control can be attained through forest management using Internet of Things. The use and adoption of IoT in forest ecosystem management is challenging due to many factors. Vast geographical areas and limited resources in terms of budget and equipment are some of the limiting factors. In digital forestry, IoT deployment offers effective operations, control, and forecasts for soil erosion, fires, and undesirable depositions. In this chapter, IoT sensing and communication applications are presented for digital forestry systems. Different IoT systems for digital forest monitoring applications are also discussed

Desafíos políticos de los países de inmigración

13 págs.-- Publicado en "Confluencia XXI. Revista de Pensamiento Político" (México), nº 3 (Oct-Dic 2008) bajo el título monográfico "Migrantes: ¿Por qué se van? ¿Por qué se quedan?".Las migraciones, una práctica tan antigua como la propia condición humana, se han convertido en un factor estructural de primer orden, en uno de los macrofenómenos más definitorios de nuestra época y en un complejo reto para las sociedades contemporáneas. En prácticamente todos los países del mundo, todo lo que concierne a este complejo fenómeno ocupa un lugar destacado en la agenda política. La gestión, el control y la integración de los movimientos internacionales de personas se presentan como un policy field de creciente y prioritaria relevancia. No se trata, sin embargo, de una cuestión de mera moda: el número de países implicados de manera significativa en las migraciones internacionales ha aumentado considerablemente, hasta el punto de que resulta realmente difícil encontrar algún Estado que no sea bien un país de inmigración, bien un país de emigración o bien ambas cosas a la vez, cuando no al menos un país de tránsito. No ha de extrañar entonces que la mayoría de los gobiernos haya tomado conciencia de la necesidad de ofrecer una respuesta en términos legales e institucionales a un fenómeno de carácter permanente que puede llegar a alterar la estructura demográfica, social, cultural, económica y laboral de un país. Dada la complejidad de la cuestión, y por cuestiones de economía argumentativa, aquí se abordará de manera fundamental desde la perspectiva de los países receptores, que, por lo demás, es también la adoptada en forma habitual por los países europeos que registran mayor inmigración. Sin embargo, el fenómeno migratorio es fundamentalmente transnacional y tiene fehacientes repercusiones en los países de emigración.Peer reviewe

Global patterns in endemicity and vulnerability of soil fungi

Fungi are highly diverse organisms, which provide multiple ecosystem services. However, compared with charismatic animals and plants, the distribution patterns and conservation needs of fungi have been little explored. Here, we examined endemicity patterns, global change vulnerability and conservation priority areas for functional groups of soil fungi based on six global surveys using a high-resolution, long-read metabarcoding approach. We found that the endemicity of all fungi and most functional groups peaks in tropical habitats, including Amazonia, Yucatan, West-Central Africa, Sri Lanka, and New Caledonia, with a negligible island effect compared with plants and animals. We also found that fungi are predominantly vulnerable to drought, heat and land-cover change, particularly in dry tropical regions with high human population density. Fungal conservation areas of highest priority include herbaceous wetlands, tropical forests, and woodlands. We stress that more attention should be focused on the conservation of fungi, especially root symbiotic arbuscular mycorrhizal and ectomycorrhizal fungi in tropical regions as well as unicellular early-diverging groups and macrofungi in general. Given the low overlap between the endemicity of fungi and macroorganisms, but high conservation needs in both groups, detailed analyses on distribution and conservation requirements are warranted for other microorganisms and soil organisms