Polarization of B -> VV: experimental status

The experimental status of the polarization measurements in B to charmless vector-vector decays by both the Belle and Babar experiments is reviewed. The results obtained in related vector-tensor, axial vector-vector, and axial vector-axial vector modes are also given.Comment: 6 pages, 5 figures, Proceedings of CKM2010, the 6th International Workshop on the CKM Unitarity Triangle, University of Warwick, UK, 6-10 September 201

Soils and paleosoils of the Galapagos Islands : what we know and what we don't know, a meta-analysis

Accessible information on Galapagos soils is very limited. Much of the existing, although still scarce, information is several decades old and not easily retrieved. The aim of this paper is to present a critical synthesis. Three local soil-forming factors (parent material, climate, and vegetation) are briefly highlighted, followed by a more detailed discussion of the hypsometric soil sequence on Santa Cruz, the only island where systematic information was recorded by a Belgian geopedological mission in 1962. Five zones are distinguished from the coast toward the top of the island: a dry coastal area, containing superficial and interstitial reddish, smectite-bearing soils between basalt blocks; a transition zone of brown, also smectite-bearing soils; and three subsequent higher zones covered by deeper, brown soils with probably andosolic characteristics. Trace element analyses point to a uniform composition of the parent material and a more progressed weathering on the higher slopes. Micromorphological characteristics of the soils are discussed. Soils of Santa Fe are comparable with those of the coastal zone of Santa Cruz but show higher amounts of P and S, probably of avian origin. Deeper, reddish clayey soils cover San Cristobal and are at least partly pre-Holocene. On the younger islands, no soils seem to be present

Large-x structure of physical evolution kernels in Deep Inelastic Scattering

The modified evolution equation for parton distributions of Dokshitzer, Marchesini and Salam is extended to non-singlet Deep Inelastic Scattering coefficient functions and the physical evolution kernels which govern their scaling violation. Considering the x->1 limit, it is found that the leading next-to-eikonal logarithmic contributions to the physical kernels at any loop order can be expressed in term of the one-loop cusp anomalous dimension, a result which can presumably be extended to all orders in (1-x), and has eluded so far threshold resummation. Similar results are shown to hold for fragmentation functions in semi-inclusive e+ e- annihilation. Gribov-Lipatov relation is found to be satisfied by the leading logarithmic part of the modified physical evolution kernels.Comment: 12 pages; version 2: eq.(4.6) and comment below corrected (main results unchanged), section on fragmentation functions added; version 3: new results added: all-order relation in section 3.5, O(1-x) terms adressed in section 5; version 4: incorrect suggestion on Gribov-Lipatov reciprocity removed; version 5: slight extension of the version to be published in Physics Letters B, contains a discussion of O((1-x)^2) terms and added reference

A micromorphological evaluation of pedogenesis on Isla Santa Cruz (Galápagos)

Thin sections of about 200 horizons or layers, representing 60 soil profiles in the coastal area and on the windward slopes of Isla Santa Cruz (Galápagos Islands) were analysed. Based on the fabric and the composition of the groundmass and the presence of pedofeatures in individual layers or horizons, clusters of similar material are made and 7 units and 3 subunits distinguished. Plotting these units on a survey map gives a good insight in the spatial distribution of soil materials, expressing different combinations of parent material and precipitation. In the coastal area and the lowest slopes, with a summer dry climate, respectively reddish and greyish and brown materials with a porphyric c/f related distribution pattern and striated b-fabrics, and often with fragmented illuvial clay coatings are observed. The coarse material contains mainly holocrystalline basalt fragments, unweathered in the coastal area, or basalt derived individual minerals. The micromass has a halloysitic-smectitic composition. On the higher slopes, with a permanent moist climate, materials have also a porphyric or fine monic c/f related distribution pattern, but the b-fabric is undifferentiated and no illuvial features are present, gibbsitic features sometimes occur and the micromass consists mainly of halloysite and gibbsite. Subunits are distinguished here according to the microstructure, and the quantity and type of coarse material. Mesocrystalline basalt, often vesicular, dominates over holocrystalline, pointing to the influence of scoria. Soils on the higher slopes are more strongly weathered than those on the drier lower slopes and the coastal area. In depressions in the higher areas, materials with a yellowish or brownish grey micromass with a striated b-fabric, and well developed limpid illuvial clay coatings and impregnative iron oxide nodules occur. The micromass has a halloysite-smectite composition. Contrary to existing hypotheses the reddish soils in the coastal area are not considered as palaeosoils (roots of tropical soils), but as modern soils developed in colluvium on the lower slopes, which was deposited on totally eroded surfaces (marine terraces?). On the slopes the distribution of units is not only determined by hypsometric zones, as suggested in literature, but is rather clustered according to types of parent material. The soils on Santa Cruz are supposed to be formed after the last interglacial period, different from the red soils of San Cristóbal which are older.<br>Se analizaron láminas delgadas de unos 200 horizontes o capas procedentes de 60 perfiles de suelos localizados en el área costera y en las laderas de barlovento de la Isla Santa Cruz (Islas Galápagos). En base a la contextura, la composición de la masa basal y la presencia de edaforasgos en las capas individuales u horizontes, se realizaron clusters de material similar y se distinguieron 7 unidades y 3 subunidades. La demarcación de estas unidades en un mapa permite obtener una buena perspectiva de la distribución espacial de los distintos materiales de suelo, que expresan diferentes combinaciones de material parental y precipitación. En la zona costera y en las laderas más bajas, con un clima con verano seco, se observan, respectivamente, materiales rojizos o grisáceos y materiales pardos con una distribución relacionada c/f tipo porfídica y contexturas birrefringentes estriadas, y frecuentemente aparecen con revestimientos de arcilla iluvial fragmentados. El material grueso contiene principalmente fragmentos de basalto holocristalino, sin meteorizar en la zona costera, o minerales individuales derivados de basalto. La micromasa tiene una composición haloisítico-esmectítica. En las laderas más elevadas, con un clima permanentemente húmedo, los materiales también tienen una distribución relacionada c/f tipo porfídica o mónica fina, pero la contextura birrefringente es indiferenciada y no aparecen rasgos iluviales, los rasgos gibsíticos aparecen alguna vez y la micromasa está formada fundamentalmente por haloysita y gibsita. En este caso las subunidades se distinguen en función de la microestructura y la cantidad y tipo de material grueso. El basalto mesocristalino, a menudo vesicular, domina sobre el holocristalino, indicando la influencia de las escorias. Los suelos sobre las laderas más elevadas están más fuertemente meteorizados que los que se encuentran en las laderas más bajas y más secas y en las zonas costeras. En las depresiones de las zonas elevadas aparecen materiales con una micromasa de amarillenta a pardo grisácea con una contextura birrefringente estriada, y revestimientos de arcilla límpida iluvial bien desarrollados y nódulos de óxidos de hierro. La micromasa está formada por haloisita y esmectita. Contrariamente a las hipótesis existentes, los suelos rojos en la zona costera no están considerados como paleosuelos (residuos de suelos tropicales) sino como suelos modernos desarrollados sobre materiales coluviales en las laderas más bajas, que fueron depositados sobre superficies totalmente erosionadas (¿terrazas marinas?). En las laderas la distribución de unidades no está solo determinada por zonas hipsométricas, tal y como sugiere la literatura, sino que está determinada sobre todo por el tipo de material original. Se supone que los suelos de Santa Cruz se han formado después del último periodo interglacial, diferentes de los suelos rojos más antiguos de San Cristóbal.<br>Lâminas delgadas de cerca de 200 horizontes ou camadas, que representam 60 perfis de solo na zona costeira e nas encostas de barlavento da Ilha de Santa Cruz (Ilhas Galápagos) foram analisadas. Com base na estrutura e composição do fundo matricial e na presença de pedocaracteres nas camadas individuais ou horizontes, podem-se estabelecer grupos de material semelhante e definir 7 unidades e 3 subunidades. Ao marcar estas unidades num mapa de levantamento, obtém-se uma boa perspectiva da distribuição espacial dos vários materiais do solo, que expressam diferentes combinações de material originário e de precipitação. Na zona costeira e encostas mais baixas, com um clima com verão seco, observam-se respectivamente materiais avermelhados ou acinzentados e materiais castanhos, com distribuição relacionada g/f porfírica e tessitura-b estriada, e muitas vezes com revestimentos de argila iluvial fragmentados. O material grosseiro contém principalmente fragmentos de basalto holocristalino, não meteorizado na zona costeira, ou minerais individuais derivados do basalto. A composição da micromassa é haloisítico-esmectítica. Nas encostas mais altas, com um clima permanentemente húmido, os materiais têm também uma distribuição relacionada g/f porfírica ou mónica fina, mas a tessitura-b é indiferenciada, não se observam pedocaracteres iluviais, pedocaracteres gibsíticos ocorrem algumas vezes e a micromassa consiste principalmente de haloisite e gibsite. Neste caso as subunidades são definidas de acordo com a microestrutura e a quantidade e tipo de material grosseiro. O basalto mesocristalino, frequentemente vesicular, é dominante relativamente ao basalto holocristalino, indicando a influência de escória. Os solos das encostas mais elevadas são mais fortemente meteorizados do que os das encostas mais baixas e mais secas e os da zona costeira. Em depressões nas áreas mais elevadas, encontram-se materiais com micromassa cinzenta amarelada ou acastanhada, tessitura-b estriada, revestimentos de argila límpida iluvial bem desenvolvidos e nódulos de óxido de ferro impregnativo. O micromassa é composta por haloisite e esmectite. Contrariamente às hipóteses existentes os solos avermelhados da zona costeira não são paleosolos (resíduos de solos tropicais), mas solos modernos desenvolvidos em material coluvial nas encostas mais baixas, que foi depositado sobre superfícies totalmente erodidas (terraços marinhos?). Nas encostas a distribuição de unidades não é apenas determinada pelas zonas hipsométricas, como sugerido na literatura, mas sobretudo determinada pelo tipo de material originário. Supõe-se que os solos em Santa Cruz se formaram após o último período interglacial, contrariamente aos solos vermelhos de San Cristóbal que são mais velhos

Eigenvalues of the basic Dirac operator on quaternion-Kahler foliations

In this paper, we give an optimal lower bound for the eigenvalues of the basic Dirac operator on a quaternion-Kahler foliation. The limiting case is characterized by the existence of quaternion-Kahler Killing spinors. We end this paper by giving some examples