6,087 research outputs found

    Devolution as process: institutional structures, state personnel and transport policy in the United Kingdom

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    Devolution has been described as a key ‘global trend’ over recent decades as governments have decentralised power and responsibilities to subordinate regional institutions (Rodriguez-Pose and Gill, 2003). UK devolution is characterised by its asymmetrical nature with different territories granted different institutional arrangements and powers. In this paper, we seek examine the role of state personnel in mobilising the new institutional machinery and managing the process of devolution, focusing on transport policy. Our research shows a clear contrast between London and Northern Ireland, on the one hand, and Scotland and Wales, on the other, in terms of the effectiveness of political leaders in creating clear policy priorities and momentum in transport

    Comparative Analysis of Non-thermal Emissions and Study of Electron Transport in a Solar Flare

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    We study the non-thermal emissions in a solar flare occurring on 2003 May 29 by using RHESSI hard X-ray (HXR) and Nobeyama microwave observations. This flare shows several typical behaviors of the HXR and microwave emissions: time delay of microwave peaks relative to HXR peaks, loop-top microwave and footpoint HXR sources, and a harder electron energy distribution inferred from the microwave spectrum than from the HXR spectrum. In addition, we found that the time profile of the spectral index of the higher-energy (\gsim 100 keV) HXRs is similar to that of the microwaves, and is delayed from that of the lower-energy (\lsim 100 keV) HXRs. We interpret these observations in terms of an electron transport model called {\TPP}. We numerically solved the spatially-homogeneous {\FP} equation to determine electron evolution in energy and pitch-angle space. By comparing the behaviors of the HXR and microwave emissions predicted by the model with the observations, we discuss the pitch-angle distribution of the electrons injected into the flare site. We found that the observed spectral variations can qualitatively be explained if the injected electrons have a pitch-angle distribution concentrated perpendicular to the magnetic field lines rather than isotropic distribution.Comment: 32 pages, 12 figures, accepted for publication in The Astronomical Journa

    Analytical electron microscopy of fine-grained phases in primitive interplanetary dust particles and carbonaceous chondrites

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    In order to describe the total mineralogical diversity within primitive extraterrestrial materials, individual interplanetary dust particles (IDPs) collected from the stratosphere as part of the JSC Cosmic Dust Curatorial Program were analyzed using a variety of AEM techniques. Identification of over 250 individual grains within one chondritic porous (CP) IDP shows that most phases could be formed by low temperature processes and that heating of the IDP during atmospheric entry is minimal and less than 600 C. In a review of the mineralogy of IDPs, it was suggested that the occurrence of other silicates such as enstatite whiskers is consistent with the formation in an early turbulent period of the solar nebula. Experimental confirmation of fundamental chemical and physical processes in a stellar environment, such as vapor phase condensation, nucleation, and growth by annealing, is an important aspect of astrophysical models for the evolution of the Solar System. A detailed comparison of chondritic IDP and carbonaceous chondrite mineralogies shows significant differences between the types of silicate minerals as well as the predominant oxides

    Tunneling edges at strong disorder

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    Scattering between edge states that bound one-dimensional domains of opposite potential or flux is studied, in the presence of strong potential or flux disorder. A mobility edge is found as a function of disorder and energy, and we have characterized the extended phase. "paper_FINAL.tex" 439 lines, 20366 characters In the presence of flux and/or potential disorder, the localization length scales exponentially with the width of the barrier. We discuss implications for the random-flux problem.Comment: RevTeX, 4 page

    Lithostratigraphy, biostratigraphy, and stable-isotope stratigraphy of cores from ODP Leg 105 site surveys, Labrador Sea and Baffin Bay

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    Trigger weight (TWC) and piston (PC) cores obtained from surveys of the three sites drilled during Ocean Drilling Program (ODP) Leg 105 were studied in detail for benthic foraminiferal assemblages, total carbonate (all sites), planktonic foraminiferal abundances (Sites 645 and 647), and stable isotopes (Sites 646 and 647). These high-resolution data provide the link between modern environmental conditions represented by the sediment in the TWC and the uppermost cores of the ODP holes. This link provides essential control data for interpretating late Pleistocene paleoceanographic records from these core holes. At Site 645 in Baffin Bay, local correlation is difficult because the area is dominated by ice-rafted deposits and by debris flows and/or turbidite sedimentation. At the two Labrador Sea sites (646 and 647), the survey cores and uppermost ODP cores can be correlated. High-resolution data from the site survey cores also provide biostratigraphic data that refine the interpretations compiled from core-catcher samples at each ODP site

    Nanopore direct RNA sequencing maps the complexity of Arabidopsis mRNA processing and m6A modification

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    Understanding genome organization and gene regulation requires insight into RNA transcription, processing and modification. We adapted nanopore direct RNA sequencing to examine RNA from a wild-type accession of the model plant Arabidopsis thaliana and a mutant defective in mRNA methylation (m6A). Here we show that m6A can be mapped in full-length mRNAs transcriptome-wide and reveal the combinatorial diversity of cap-associated transcription start sites, splicing events, poly(A) site choice and poly(A) tail length. Loss of m6A from 3’ untranslated regions is associated with decreased relative transcript abundance and defective RNA 30 end formation. A functional consequence of disrupted m6A is a lengthening of the circadian period. We conclude that nanopore direct RNA sequencing can reveal the complexity of mRNA processing and modification in full-length single molecule reads. These findings can refine Arabidopsis genome annotation. Further, applying this approach to less well-studied species could transform our understanding of what their genomes encode

    Kinetics in a turbulent nebular cloud

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    Model calculations, which include the effects of turbulence during subsequent solar nebula evolution after the collapse of a cool interstellar cloud, can reconcile some of the apparent differences between physical parameters obtained from theory and the cosmochemical record. Two important aspects of turbulence in a protoplanetary cloud include the growth and transport of solid grains. While the physical effects of the process can be calculated and compared with the probable remains of the nebula formulation period, the more subtle effects on primitive grains and their survival in the cosmochemical record cannot be readily evaluated. The environment offered by the Space Station (or Space Shuttle) experimental facility can provide the vacuum and low gravity conditions for sufficiently long time periods required for experimental verification of these cosmochemical models

    Possible Jurassic age for part of Rakaia Terrane: implications for tectonic development of the Torlesse accretionary prism

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    Greywacke sandstone and argillite beds comprising Rakaia Terrane (Torlesse Complex) in mid Canterbury, South Island, New Zealand, are widely regarded as Late Triassic (Norian) in age based on the occurrence of Torlessia trace fossils, Monotis, and other taxa. This paleontological age assignment is tested using published 40Ar/39Ar mica and U-Pb zircon ages for these rocks and published and new zircon fission track (FT) ages. The youngest U-Pb zircon ages in the Rakaia Terrane rocks in mid Canterbury are Norian, whereas 10-20% of the 40Ar/39Ar muscovite ages are younger than Norian. Numerical modelling of these mica ages shows that they cannot have originated from partial thermal overprinting in the Torlesse prism if the thermal maximum was short-lived and early in the prism history (210-190 Ma), as commonly inferred for these rocks. The young component of mica ages could, however, be explained by extended residence (200-100 Ma) at 265-290deg.C in the prism. Early Jurassic (c. 189 Ma) zircon FT ages for sandstone beds from Arthur's Pass, the Rakaia valley, and the Hermitage (Mt Cook) are interpreted not to have experienced maximum temperatures above 210deg.C, and therefore cannot have been reduced as a result of partial annealing in the Torlesse prism. This is based on identification of a fossil Cretaceous, zircon FT, partial annealing zone in low-grade schists to the west, and the characteristics of the age data. The Early Jurassic zircon FT ages and the young component of 40Ar/39Ar mica ages are regarded therefore as detrital ages reflecting cooling in the source area, and constrain the maximum depositional age of parts of the Rakaia Terrane in mid Canterbury. The zircon FT data also show the initiation (c. 100 Ma) of marked and widespread Late Cretaceous cooling of Rakaia Terrane throughout Canterbury, which is attributed to uplift and erosion of inboard parts of the Torlesse prism due to continuing subduction accretion at its toe. The critical wedge concept is proposed as a new framework for investigating the development of the Torlesse Complex. The Rakaia Terrane may have formed the core of an accretionary wedge imbricated against the New Zealand margin during the Middle or Late Jurassic. Late Jurassic nonmarine sediments (e.g., Clent Hills Formation) accumulated upon the inner parts of the prism as it enlarged, emerged, and continued to be imbricated. Exhumation of Otago Schist from c. 135 Ma may mark the development of a balance (steady state) between sediments entering the prism at the toe and material exiting at the inboard margin. The enlargement of the area of exhumation to all of Canterbury from c. 100 Ma may reflect a dynamic response to widening of the prism through the accretion of Cretaceous sediments. The model of a dynamic critical wedge may help to explain the various expressions of the Rangitata Orogeny

    Modified Petri net model sensitivity to workload manipulations

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    Modified Petri Nets (MPNs) are investigated as a workload modeling tool. The results of an exploratory study of the sensitivity of MPNs to work load manipulations in a dual task are described. Petri nets have been used to represent systems with asynchronous, concurrent and parallel activities (Peterson, 1981). These characteristics led some researchers to suggest the use of Petri nets in workload modeling where concurrent and parallel activities are common. Petri nets are represented by places and transitions. In the workload application, places represent operator activities and transitions represent events. MPNs have been used to formally represent task events and activities of a human operator in a man-machine system. Some descriptive applications demonstrate the usefulness of MPNs in the formal representation of systems. It is the general hypothesis herein that in addition to descriptive applications, MPNs may be useful for workload estimation and prediction. The results are reported of the first of a series of experiments designed to develop and test a MPN system of workload estimation and prediction. This first experiment is a screening test of MPN model general sensitivity to changes in workload. Positive results from this experiment will justify the more complicated analyses and techniques necessary for developing a workload prediction system
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