838 research outputs found

    Consideracions sobre la indústria cotonera i la seva evolució a Barcelona, 1730-1840

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    First Record of Bonefish, Albula vulpes, from Mississippi Coastal Waters

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    Bonefish (Albula spp.), Family Albulidae, occur worldwide in coastal waters of tropical and warm temperate seas (Crabtree et al. 1997), and 2 species, A. vulpes and A. nemoptera, are recognized from the western Atlantic Ocean (Rivas and Warlen 1967). The normal range of A. vulpes in the western Atlantic extends from Bermuda to Brazil, including the Bahamas, Cuba, Mexico, Central America and the Antilles (Hildebrand 1963), but in US waters, A. vulpes typically occurs off south Florida (Crabtree et al. 1997). In contrast, A. nemoptera has been reported from Panama, Colombia, Venezuela, Jamaica and Hispaniola (Uyeno et al. 1983). Published accounts of A. vulpes from the northcentral Gulf of Mexico (hereafter GOM) are rare. Ogren and Brusher (1977) collected a single specimen of A. vulpes from St. Andrew Bay, Florida but did not report its size. Thompson and Deegan (1982) reported the collection of 3 A. vulpes leptocephali (range: 34.8–53.5 mm standard length (SL)) from Louisiana coastal waters, and Boschung (1992) reported a single A. vulpes juvenile (37 mm SL) collected from Grand Bay, Alabama. We report the first record of A. vulpes from Mississippi

    Control of Escherichia coli O157:H7 in large-diameter, lebanon-style bologna

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    Lebanon bologna raw batter was mixed with a five-strain mixture of Escherichia coli O157:H7 to achieve average inoculum levels of 7.79, 7.77, and 7.92 log CFU/g as deter mined on MSA, 202, and PRSA media, respectively. Treatment 1 consisted of a fermentation cycle of 8 hrs at an internal temperature (I.T.) of 80EF then 24 hrs at 100EF I.T., followed by 24 hrs at 110EF I.T. Treatments 2, 3, and 4 included additional heating at 115EF I.T. for 1, 2, and 5 hrs, respectively. All heat treatments resulted in product that was negative (\u3c1.9 log CFU/g detection limit) on all culture media and negative after enrichment on mEC selective medium. This study validates that a five-log reduction of E. coli O157:H7 can be achieved using the described protocol, thus meeting USDA/FSIS requirements

    A global reanalysis of nuclear parton distribution functions

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    We determine the nuclear modifications of parton distribution functions of bound protons at scales Q21.69Q^2\ge 1.69 GeV2^2 and momentum fractions 105x110^{-5}\le x\le 1 in a global analysis which utilizes nuclear hard process data, sum rules and leading-order DGLAP scale evolution. The main improvements over our earlier work {\em EKS98} are the automated χ2\chi^2 minimization, simplified and better controllable fit functions, and most importantly, the possibility for error estimates. The resulting 16-parameter fit to the N=514 datapoints is good, χ2/d.o.f=0.82\chi^2/{\rm d.o.f}=0.82. Within the error estimates obtained, the old {\em EKS98} parametrization is found to be fully consistent with the present analysis, with no essential difference in terms of χ2\chi^2 either. We also determine separate uncertainty bands for the nuclear gluon and sea quark modifications in the large-xx region where they are not stringently constrained by the available data. Comparison with other global analyses is shown and uncertainties demonstrated. Finally, we show that RHIC-BRAHMS data for inclusive hadron production in d+Au collisions lend support for a stronger gluon shadowing at x<0.01x<0.01 and also that fairly large changes in the gluon modifications do not rapidly deteriorate the goodness of the overall fits, as long as the initial gluon modifications in the region x0.020.04x\sim 0.02-0.04 remain small.Comment: 33 pages, 14 figure

    Commission 10: Solar Activity

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    Commission 10 aims at the study of various forms of solar activity, including networks, plages, pores, spots, fibrils, surges, jets, filaments/prominences, coronal loops, flares, coronal mass ejections (CMEs), solar cycle, microflares, nanoflares, coronal heating etc., which are all manifestation of the interplay of magnetic fields and solar plasma. Increasingly important is the study of solar activities as sources of various disturbances in the interplanetary space and near-Earth “space weather”. Over the past three years a major component of research on the active Sun has involved data from the RHESSI spacecraft. This review starts with an update on current and planned solar observations from spacecraft. The discussion of solar flares gives emphasis to new results from RHESSI, along with updates on other aspects of flares. Recent progress on two theoretical concepts, magnetic reconnection and magnetic helicity is then summarized, followed by discussions of coronal loops and heating, the magnetic carpet and filaments. The final topic discussed is coronal mass ejections and space weather. The discussions on each topic is relatively brief, and intended as an outline to put the extensive list of references in context. The review was prepared jointly by the members of the Organizing Committee, and the names of the primary contributors to the various sections are indicated in parentheses

    Blockchain for Power Grids

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    Sharing information is an important part of regulating and maintaining efficient and safe power grids. This project’s goal is to develop a way of using blockchain technology to share transaction information among different power grids in a secure, controlled, monitored, and efficient manner. The biggest concern regarding the data is integrity. By leveraging blockchain technology, the data will be reliable and resilient to attacks, such as man-in-the-middle and data spoofing attacks. The Hyperledger Fabric implementation provides a permissioned network in which power grids will act as nodes that maintain ledger information. By using a distributed ledger to validate transactions through the process of consensus, the system can share information in a manner that is more secure and transparent than traditional information sharing systems in which data is less secure and takes longer to validate. The additional layers of security and speed that Hyperledger technology provides help to prevent issues, such as power grid failures, that could stem from the latency or integrity issues involved with traditional methods of validating, processing, and reacting to shared data

    Control of Escherichia coli O157:H7 in large-diameter, lebanon-style bologna

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    Lebanon bologna raw batter was mixed with a five-strain mixture of Escherichia coli O157:H7 to achieve average inoculum levels of 7.79, 7.77, and 7.92 log CFU/g as deter mined on MSA, 202, and PRSA media, respectively. Treatment 1 consisted of a fermentation cycle of 8 hrs at an internal temperature (I.T.) of 80EF then 24 hrs at 100EF I.T., followed by 24 hrs at 110EF I.T. Treatments 2, 3, and 4 included additional heating at 115EF I.T. for 1, 2, and 5 hrs, respectively. All heat treatments resulted in product that was negative (<1.9 log CFU/g detection limit) on all culture media and negative after enrichment on mEC selective medium. This study validates that a five-log reduction of E. coli O157:H7 can be achieved using the described protocol, thus meeting USDA/FSIS requirements

    Confined granular packings: structure, stress, and forces

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    The structure and stresses of static granular packs in cylindrical containers are studied using large-scale discrete element molecular dynamics simulations in three dimensions. We generate packings by both pouring and sedimentation and examine how the final state depends on the method of construction. The vertical stress becomes depth-independent for deep piles and we compare these stress depth-profiles to the classical Janssen theory. The majority of the tangential forces for particle-wall contacts are found to be close to the Coulomb failure criterion, in agreement with the theory of Janssen, while particle-particle contacts in the bulk are far from the Coulomb criterion. In addition, we show that a linear hydrostatic-like region at the top of the packings unexplained by the Janssen theory arises because most of the particle-wall tangential forces in this region are far from the Coulomb yield criterion. The distributions of particle-particle and particle-wall contact forces P(f)P(f) exhibit exponential-like decay at large forces in agreement with previous studies.Comment: 11 pages, 11 figures, submitted to PRE (v2) added new references, fixed typo

    Dynamical Renormalization Group Approach to Quantum Kinetics in Scalar and Gauge Theories

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    We derive quantum kinetic equations from a quantum field theory implementing a diagrammatic perturbative expansion improved by a resummation via the dynamical renormalization group. The method begins by obtaining the equation of motion of the distribution function in perturbation theory. The solution of this equation of motion reveals secular terms that grow in time, the dynamical renormalization group resums these secular terms in real time and leads directly to the quantum kinetic equation. We used this method to study the relaxation in a cool gas of pions and sigma mesons in the O(4) chiral linear sigma model. We obtain in relaxation time approximation the pion and sigma meson relaxation rates. We also find that in large momentum limit emission and absorption of massless pions result in threshold infrared divergence in sigma meson relaxation rate and lead to a crossover behavior in relaxation. We then study the relaxation of charged quasiparticles in scalar electrodynamics (SQED). While longitudinal, Debye screened photons lead to purely exponential relaxation, transverse photons, only dynamically screened by Landau damping lead to anomalous relaxation, thus leading to a crossover between two different relaxational regimes. We emphasize that infrared divergent damping rates are indicative of non-exponential relaxation and the dynamical renormalization group reveals the correct relaxation directly in real time. Finally we also show that this method provides a natural framework to interpret and resolve the issue of pinch singularities out of equilibrium and establish a direct correspondence between pinch singularities and secular terms. We argue that this method is particularly well suited to study quantum kinetics and transport in gauge theories.Comment: RevTeX, 40 pages, 4 eps figures, published versio

    Raman spectroscopy of laser irradiated titanium dioxide.

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    Raman spectroscopy is applied to investigate the effect of exposure to high power laser radiation on the crystalline phases of TiO2. Measurement of the changes in the Raman spectra of TiO2 with exposure to laser radiation was reported. This has proved to be a useful sensor in monitoring both the structure and the kinetics process of change in crystalline phases from anatase to rutile during exposure to laser irradiation
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