QCD Scaling Violation at Small x

We investigate the evolution of parton densities at small values of the momentum fraction, x, by including resummed anomalous dimensions in the renormalization group equations. The resummation takes into account the leading-logarithmic contributions (\alpha_S \ln x)^k given by the BFKL equation and the next-to-leading-logarithmic corrections from quark evolution. We present numerical results for the parton densities and the deep inelastic structure function F_2.Comment: 8 pages, Latex, 3 uuencoded figure

Soft-gluon resolution scale in QCD evolution equations

QCD evolution equations can be recast in terms of parton branching processes. We present a new numerical solution of the equations. We show that this parton-branching solution can be applied to analyze infrared contributions to evolution, order-by-order in the strong coupling $\alpha_s$, as a function of the soft-gluon resolution scale parameter. We examine the cases of transverse-momentum ordering and angular ordering. We illustrate that this approach can be used to treat distributions which depend both on longitudinal and on transverse momenta.Comment: Latex, 8 pages, 4 figure

Collinear and TMD Quark and Gluon Densities from Parton Branching Solution of QCD Evolution Equations

We study parton-branching solutions of QCD evolution equations and present a method to construct both collinear and transverse momentum dependent (TMD) parton densities from this approach. We work with next-to-leading-order (NLO) accuracy in the strong coupling. Using the unitarity picture in terms of resolvable and non-resolvable branchings, we analyze the role of the soft-gluon resolution scale in the evolution equations. For longitudinal momentum distributions, we find agreement of our numerical calculations with existing evolution programs at the level of better than 1 percent over a range of five orders of magnitude both in evolution scale and in longitudinal momentum fraction. We make predictions for the evolution of transverse momentum distributions. We perform fits to the high-precision deep inelastic scattering (DIS) structure function measurements, and we present a set of NLO TMD distributions based on the parton branching approach.Comment: 27 pages, 8 figure

Color transparency in deeply inelastic diffraction

We suggest a simple physical picture for the diffractive parton distributions that appear in diffractive deeply inelastic scattering. In this picture, partons impinging on the proton can have any transverse separation, but only when the separation is small can they penetrate the proton without breaking it up. By comparing the predictions from this picture with the diffractive data from HERA, we determine rough values for the small separations that dominate the diffraction process.Comment: 10 pages, 2 figures; v2: citations added, two comments revised and expanded, results unchange

Palaeoecology of the Spathian Virgin Formation (Utah, USA) and its implications for the Early Triassic recovery

The Spathian (late Early Triassic) Virgin Formation of south-western Utah (U.S.A.) yields a comparatively diverse benthic fauna that flourished ~2 Ma after the end-Permian mass extinction. In this study, we present quantitative palaeoecological data, which are analysed in the context of their depositional environments. This integrated approach helps to discriminate between effects of the end-Permian mass extinction event and local environmental factors on alpha diversity and ecological structure of the Virgin Fauna. Shallow subtidal environments yield the highest species richness and lowest dominance values as recorded in two benthic associations, the Eumorphotis sp. A Association and the Protogusarella smithi Association, both of which contain 20 benthic species (bivalves, gastropods, brachiopods, echinoderms, and porifers). Tidal inlet deposits yield a low diverse fauna (Piarorhynchella triassica Association) with a very high dominance of filter feeders adapted to high energy conditions. Another comparably low diverse fauna is recorded by the Bakevellia exporrecta Association, which is recorded in deposits of the offshore transition zone, most likely reflecting unconsolidated substrates. A single sample containing five bivalve species (Bakevellia costata Assemblage) is recorded from a marginal-marine setting. The Virgin fauna yields a bulk diversity of 30 benthic species (22 genera) of body fossils and 14 ichnogenera and, thus, represents the most diverse marine bottom fauna known so far from the Early Triassic. Our results suggest that oceanographic conditions during the early Spathian enabled ecosystems to rediversify without major abiotic limitations. However, taxonomical differentiation between habitats was still low, indicating a time lag between increasing within-habitat diversity (alpha diversity) and the onset of taxonomical differentiation between habitats (beta diversity). We suggest that taxonomical habitat differentiation after mass extinction events starts only when within-habitat competition exceeds a certain threshold, which was not yet reached in the Spathian of the investigated area. This interpretation is an alternative to previous suggestions that the prevalence of generalistic taxa in the aftermath of mass extinction events reflects protracted environmental stress. The onset of increasing beta diversity is a potential criterion for distinguishing two major recovery phases, the first ending with habitat saturation and the second ending with the completion of ecosystem differentiation

TMDlib and TMDplotter: library and plotting tools for transverse-momentum-dependent parton distributions

Transverse-momentum-dependent distributions (TMDs) are central in high-energy physics from both theoretical and phenomenological points of view. In this manual we introduce the library, TMDlib, of fits and parameterisations for transverse-momentum-dependent parton distribution functions (TMD PDFs) and fragmentation functions (TMD FFs) together with an online plotting tool, TMDplotter. We provide a description of the program components and of the different physical frameworks the user can access via the available parameterisations.Comment: version 2, referring to TMDlib 1.0.2 - comments and references adde

Проект цеха получения порошкообразного тантала с помощью магнийтермического восстановления пентаоксида тантала, производительностью 40 т/год по танталовому порошку

В данном дипломном проекте была предложена аппаратурно-технологическая схема получения порошкообразного тантала с помощью магнийтермического восстановления пентаоксида тантала, производительностью 40 т/год по танталовому порошку. На основе данных материальных балансов было подобрано основное и вспомогательное оборудование для проведения магнийтермического восстановления. Основным аппаратом выбрана установка стесненного падения для проведения восстановления оксида тантала магнием высотой 2,6 м, диаметр-0,25 м. На основе подобранного технологического оборудования разработан цех магнийтермического восстановления. Был произведен расчет заработной платы работников. Рассчитана себестоимость конечного полупродукта. Рассмотрены основные пункты социальной ответственности.In the diploma project was proposed an instrumentation-technological scheme for the processing of obtaining powdered tantalum by means of magnesium-thermal reduction of tantalum pentoxide, with a capacity of 40 tons per year for tantalum powder. Based on the data of material balances, the main and auxiliary equipment for magnesium-thermal recovery was selected. Was chosen the main device - cramped fall installation to carry out the reduction of tantalum oxide with magnesium 2.6 m in height,diameter-0.25 m. On the basis of the selected auxiliary equipment, was made a plan of the working area .The calculation of the personnel number of the personnel, the basic wage fund, the cost of the final semi-product has been made. Was introduced with the main points of social responsibility

QCD

We discuss QCD studies that will be possible at LEP2. We examine both experimental and theoretical aspects of jets, fragmentation functions, multiplicities and particle spectra.Comment: 44 pages, Latex, epsfig, 18 figures, to appear on the Report of the Workshop on Physics at LEP2, CERN 96-01, vol. 1, 199

5-Aminolaevulinic Acid (ALA) for the Fluorescence Detection of Bronchial Tumors

At the moment only early detection of lung cancer offers a good prognosis for the patients. Conventional white light endoscopy is mostly insufficient for early diagnosis. Therefore we developed a system of fluorescence diagnosis using 5-aminolaevulinic acid (ALA) exogeneously applied. As precursor of the heme synthesis it is metabolized to protoporphyrin IX – a red fluorescent substance. Therefore protoporphyrin IX accumulates in tumorous and premalignant tissue, and can be directly visualized by fluorescence bronchoscopy. Excitation with blue light (380–435 nm) causes a red fluorescence, which can be detected after filtering most of the blue component with the naked eye or a camera system. After earlier work with laser systems and cold light sources we now use the system D-Light AF for the fluorescence diagnosis using ALA-induced protoporphyrin IX fluorescence

Strain field analysis on Montserrat (W.I.) as tool for assessing permeable flow paths in the magmatic system of Soufrière Hills Volcano

Strain dilatometers have been operated on the volcanic island of Montserrat (West Indies) for more than a decade and have proven to be a powerful technique to approach short-term dynamics in the deformational field in response to pressure changes in the magmatic system of the andesitic dome-building Soufrière Hills Volcano (SHV). We here demonstrate that magmatic activity in each of the different segments of the SHV magmatic system (shallow dyke-conduit, upper and lower magma chambers) generates a characteristic strain pattern that allows the identification of operating sources in the plumbing system based on a simple scheme of amplitude ratios. We use this method to evaluate strain data from selected Vulcanian explosions and gas emission events that occurred at SHV between 2003 and 2012. Our results show that the events were initiated by a short phase of contraction of either one or both magma chambers and a simultaneous inflation of the shallow feeder system. The initial phase of the events usually lasted only tens to hundreds of seconds before the explosion/gas emission started and the system recovered. The short duration of this process points at rapid transport of fluids rather than magma ascent to generate the pressure changes. We suggest the propagation of tensile hydraulic fractures as viable mechanism to provide a pathway for fluid migration in the magmatic system at the observed time scale. Fluid mobilization was initiated by a sudden destabilization of large pockets of already segregated fluid in the magma chambers. Our study demonstrates that geodetic observables can provide unprecedented insights into complex dynamic processes within a magmatic system commonly assessed by theoretical modeling and petrologic observations. Key Points Strain data analysis from explosions/degassing events at Soufriere Hills Volcano Pressure release deep within the magmatic system sec-min prior to events Rapid gas rise from magma reservoir to surface via tensile hydraulic fractures © 2014. American Geophysical Union. All Rights Reserved