Gluon propagator, triple gluon vertex and the QCD coupling constant

We study the UV-scaling of the flavorless gluon propagator in the Landau gauge in an energy window up to 9 GeV. Dominant hypercubic lattice artifacts are eliminated. A large set of renormalization schemes is used to test asymptotic scaling. We compare with our results obtained directly from the triple gluon vertex. We end-up with \Lambda_{\bar{\rm{MS}}} = 318(12)(5) MeV and 292(5)(15) MeV respectively for these two methods, compatible which each other but significantly above the Schrodinger method estimate.Comment: 3 pages, LaTeX with two figures; presented at LATTICE9

Paleoseismological analysis of late Miocene lacustrine successions in the Prebetic Zone, SE Spain

A paleoseismological study of late Miocene lacustrine sediments was carried out in the Neogene basins of the Prebetic Zone in Albacete (Spain). We developed a multidisciplinary methodology which could be used to extrapolate the paleoseismic data to the present day. This multidisciplinary approach includes different disciplines, i.e. stratigraphy, structural analysis, seismological analysis and paleoseismology. Paleoseismological analysis was focussed on both shallow and deep lake deposits given that these sediments behave differently in different deformation fields. The seismites formed in shallow sediments were generated by liquefaction and include: sand dikes, pillow structures and intruded and fractured gr avels. The deep lake deposits show varied structures, such as loop bedding, disturbed varved lamination, mixed layers and pseudonodules. Seismites indicate paleoearthquake magnitude intervals. The trends of the seismites are usually oriented ve ry close to the stress field trends (from the late Miocene to the Present): NW-SE and NE-SW trends. This constitutes a link between tectonics and seismites. The va rved annual sedimentation evidenced by the deep lake facies was used as a relative dating method. Mixed layers were employed as paleoseismic indicators to calculate the earthquake recurrence interval. The mean recurrence interval is close to 130 years (9446 years of total record with 73 dated events), one maximum interval of 454 years and one minimum interval of 23 years and the mean estimated magnitude value is 5.1. The Gutenberg-Richter relationship shows similar "b" values close to 0.86 from paleoseismological and seismological data. This suggests that the seismic conditions have been similar since the late Miocene

The Pion Light-Cone Wave Function Phi_pi on the lattice: a partonic signal?

We determine the conditions required to study the pion light-cone wave function Phi_pi with a new method: a direct display of the partons constituting the pion. We present the preliminary results of a lattice computation of Phi_pi following this direction. An auxiliary scalar-quark is introduced. The spectroscopy of its bound states is studied. We observe some indications of a partonic behavior of the system of this scalar-quark and the anti-quark.Comment: 3 pages, 4 figures, Lattice2001(matrixelement

Tipología y significado de bioturbaciones en facies evaporíticas continentales: Mioceno de la Cuenca de Madrid

Los complejos lacustres desarrollados durante el Mioceno en la Cuenca de Madrid están en buena parte constituidos por depósitos evaporíticos dentro de los cuales se reconocen diversos tipos de icnitas. En función del grado de bioturbación del sedimento, de la geometría y morfología de las trazas, sus dimensiones, estructuración interna y tipo de relleno, así como de las facies en que se presentan, se han distinguido seis tipos de icnitas: 1) Sistemas de chimeneas y túneles con relleno pasivo y diámetro de orden rnilimétrico, 2) Sistemas de chimeneas y túneles con relleno pasivo y diámetro de orden centimétrico, 3) Chimeneas y túneles con relleno en menisco y diámetro subrnilimétrico-rnilimétrico, 4) Chimeneas y túneles con relleno en menisco y diámetro de orden centimétrico, 5) Tubos con ramas verticales y horizontales, relleno masivo y diámetro de orden centimétrico, y 6) Pisadas de vertebrados. Los organismos causantes de estas bioturbaciones son, en el caso de las icnitas de tipo 1 y 2, raices de plantas, herbáceas en el primer caso y arbustos en el segundo. Las icnitas de tipo 3, 4 Y 5 son debidas a la acción de insectos (larvas de Chironomidae?, etc ... ) y anélidos. Tanto los insectos como los anélidos pueden haber tenido un cierto papel en la formación de algunas icnitas de tipo 1. Por su parte, las pisadas de vertebrados, atribuidas en algunas ocasiones a Hiénidos de pequeño tamaño y en otras a animales de mayor envergadura, forman un grupo aparte por sus características morfológicas. Los diferentes tipos de icnitas reconocidos se presentan por lo general asociados a una o más facies sedimentarias evaporíticas. Se han distinguido un total de 6 asociaciones de facies que comprenden ambientes y/o subambientes de llanura lutítica, margen lacustre y zonas lacustres más abiertas, apreciándose diferencias en cuanto al carácter efímero o perenne de estos lagos salinos. Las bioturbaciones presentes en los sedimentos evaporíticos estudiados permiten avanzar en la casuística de la interrelación bioturbación-alteración del sedimento y control de éstas sobre procesos diagenéticos, tanto tempranos como más tardíos, en depósitos evaporíticos. Los efectos de la bioturbación se centran en aspectos tales como distribución de carbonato y zonas de oxidación/reducción en el sedimento, reemplazarnientos (p. ej. silicificaciones) y cementaciones, entre otrosLake complexes developed in the Madrid Basin through Miocene are largely formed of evaporite deposits (Calvo et al., 1989 a; Ordóñez et al., 1991). Several types of ichnites can be recognized within these sediments. On the basis of bioturbation degree, trace geometries and magnitudes, intemal filling, and lithofacies in which the traces occur, six types of ichnites have been distinguished: 1) shaft and tunnel network formed of millimetric, passive filled tubes, 2) shaft and tunnel network forrned of centimetric, passive filled tubes, 3) shafts and tunnels (burrows) showing back-filling, submillimetric to millimetric in diameter, 4) shafts and tunnels (burrows) with back-filling, centimetric in diameter, 5) traces with vertical and horizontal branches showing massive :filling-centimetric in diameter, and 6) vertebrate tracks. The bioturbation of the evaporite sediments was caused either by plant roots, which is the case for type-1 (grass roots) and type-2 (bushes), or anirnals. Types-3, 4 and 5 are thought to be due to insects (larvae of Chironomidae?, etc ... ) and annelids. Insects and annelids also could play sorne role on the formation of sorne type-1 ichnites. On the other hand, vertebrate tracks, which may be attributed to small Hyenids or other bigger marnmals, form a separate group of ichnites. Each ichnite type occurs cornmon1y associated with one or more sedimentary facies. Six different facies associations that inelude the described ichnites have been distinguished: A) Mudflat -saline lake facies association, the flats being related to small alluvial fans; B) Mudflat-saline lake complex related to widely developed alluvial systems, C) Mudflat-ephemeral carbonate pond subenvironrnent; D) Mudflat-lake margin facies association; E) Ephemeral saline lake; and F) Lake margin-open saline 1ake association. An idealized model of distribution of the ichnites in these depositional systems is proposed. Bioturbation of the primary evaporite deposits leads to modification ofboth texti,rre and fabric thus conditionating early and later diagenetic processes within the sedimento In this paper sorne of these aspects are considered and we make sorne emphasis on the role of bioturbation in diagenetic processes such as replacement and cementation of the evaporite depositsDepto. de Mineralogía y PetrologíaFac. de Ciencias GeológicasTRUEpu

Axonal T₂ estimation using the spherical variance of the strongly diffusion-weighted MRI signal.

In magnetic resonance imaging, the application of a strong diffusion weighting suppresses the signal contributions from the less diffusion-restricted constituents of the brain's white matter, thus enabling the estimation of the transverse relaxation time T <sub>2</sub> that arises from the more diffusion-restricted constituents such as the axons. However, the presence of cell nuclei and vacuoles can confound the estimation of the axonal T <sub>2</sub> , as diffusion within those structures is also restricted, causing the corresponding signal to survive the strong diffusion weighting. We devise an estimator of the axonal T <sub>2</sub> based on the directional spherical variance of the strongly diffusion-weighted signal. The spherical variance T <sub>2</sub> estimates are insensitive to the presence of isotropic contributions to the signal like those provided by cell nuclei and vacuoles. We show that with a strong diffusion weighting these estimates differ from those obtained using the directional spherical mean of the signal which contains both axonal and isotropically-restricted contributions. Our findings hint at the presence of an MRI-visible isotropically-restricted contribution to the signal in the white matter ex vivo fixed tissue (monkey) at 7T, and do not allow us to discard such a possibility also for in vivo human data collected with a clinical 3T system

Fast k-NN classifier for documents based on a graph structure

In this paper, a fast k nearest neighbors (k-NN) classifier for documents is presented. Documents are usually represented in a high-dimensional feature space, where terms appeared on it are treated as features and the weight of each term reflects its importance in the document. There are many approaches to find the vicinity of an object, but their performance drastically decreases as the number of dimensions grows. This problem prevents its application for documents. The proposed method is based on a graph index structure with a fast search algorithm. It’s high selectivity permits to obtain a similar classification quality than exhaustive classifier, with a few number of computed distances. Our experimental results show that it is feasible the use of the proposed method in problems of very high dimensionality, such as Text Mining

Power Corrections to Perturbative QCD and OPE in Gluon Green Functions

We show that QCD Green functions in Landau Gauge exhibit sizable $O(1/\mu^2)$ corrections to the expected perturbative behavior at energies as high as 10 GeV. We argue that these are due to a $$-condensate which does not vanish in Landau gauge.Comment: 3 pages 1 figure lattice2001 (gaugetheories

Sedimentología de la Fm Escucha (Albiense inferior-medio) entre Estercuel y Crivillén (Teruel) en la Cubeta de Oliete (Cuenca Ibérica Central)

A stratigraphie and sedimentologic study about the Escucha Fm (Lower-Middle Albian) has been done in the Oliete Subbasin (Central Iberian Basin). This lithostratighapic unit was developped during the last moments of the second rift state (Upper Jurassic-Lower Cretaceous), that affected the Iberian Basin. Sixteen facies has been distinguished and gathered in five characteristic facies associations: flood plain, marshftaay margin, interdistributary bay, crevasse splay and distributary channel. These facies associations belong to different sedimentary subenvironments developped in the proximal sector of a deltaic depositional system. The vertical sedimentary evolution shows a trend to more continental conditions from base to top. Different Albian macroflora remains have been found in different stratigraphic levels