2,536 research outputs found
Concurrent 43 and 86 GHz Very Long Baseline Polarimetry of 3C273
We present sub-milliarcsecond resolution total intensity and linear
polarization VLBI images of 3C273, using concurrent 43 and 86 GHz data taken
with the Very Long Baseline Array in May 2002. The structure seen in the
innermost jet suggest that we have fortuitously caught the jet in the act of
changing direction. The polarization images confirm that the core is
unpolarized (fractional polarization m < 1 %) at 86 GHz, but also show well
ordered magnetic fields (m ~ 15 %) in the inner jet, at a projected distance of
2.3 pc from the core. In this strongly polarized region, the rotation measure
changes across the jet by 4.2 x 10^{4} rad m^{-2} over an angular width of
about 0.3 milliarcseconds. If the lack of polarization in the core is also
attributed to a Faraday screen, then a rotation measure dispersion > 5.2 x
10^{4} rad m^{-2} must be present in or in front of that region. These are
among the highest rotation measures reported so far in the nucleus of any
active galaxy or quasar, and must occur outside (but probably close to) the
radio emitting region. The transverse rotation measure gradient is in the same
sense as that observed by Asada et al and by Zavala and Taylor at greater core
distances. The magnitude of the transverse gradient decreases rapidly with
distance down the jet, and appears to be variable.Comment: 4 pages, LaTeX, 3 postscript figures, submitted to Astrophysical
Journal Letter
Inspiring Music for All: next steps in innovation, improvement and integration
The report, funded by the Paul Hamlyn Foundation, provides an overview of schools-based music education in England. It represents the outcomes of research undertaken in January and February 2014 which included detailed literature reviews, personal interviews with thirty-five specialists involved in leading various organisations responsible for different aspects of music education, focus group discussions and an on-line survey of the music education workforce that generated 515 responses. The findings suggest that the place and status of music in schools vary widely across the country. The best music in schools is significantly more inclusive, more musically diverse and better quality that it was a decade ago. However, the quality and reach of schools-based music education is still unacceptably variable and inconsistent at both primary and secondary levels. Detailed findings and recommendations are included in the report
Appearance-based localization for mobile robots using digital zoom and visual compass
This paper describes a localization system for mobile robots moving in dynamic indoor environments, which uses probabilistic integration of visual appearance and odometry information. The approach is based on a novel image matching algorithm for appearance-based place recognition that integrates digital zooming, to extend the area of application, and a visual compass. Ambiguous information used for recognizing places is resolved with multiple hypothesis tracking and a selection procedure inspired by Markov localization. This enables the system to deal with perceptual aliasing or absence of reliable sensor data. It has been implemented on a robot operating in an office scenario and the robustness of the approach demonstrated experimentally
Development of Vegetation Communities in a Retrogressive Thaw Slump near Mayo, Yukon Territory : A 10-year Assessment
The vegetation in a retrogressive thaw slump, first surveyed and documented in 1987, was revisited 10 years later to investigate its subsequent development and to test a chronosequence-based successional model. The thaw slump stabilized in 1994, when the headwall became covered by organic and mineral debris. As a result, the meltwater supply from headwall ablation ceased. Alteration of environmental conditions due to stabilization of the headwall diverted the vegetation succession from the chronosequence determined in 1987. Areas that were marshy in 1987 dried up, and an area dominated by Polygonum alaskanum appeared close to the headwall. Much of the thaw slump was dominated by Salix spp. in 1997, rather than the Equisteum of 1987. However, the ground more than 200 m from the headwall, over a decade old in 1987, experienced less change in edaphic conditions, and the communities there continued to develop a structure approaching the surrounding undisturbed forest.La vĂ©gĂ©tation situĂ©e dans un dĂ©crochement de fonte rĂ©gressif, Ă©tudiĂ©e et documentĂ©e pour la premiĂšre fois en 1987, a fait l'objet d'une autre Ă©tude sur place dix ans plus tard pour examiner son Ă©volution et tester un modĂšle de succession fondĂ© sur la chronosĂ©quence. Le dĂ©crochement de fonte s'est stabilisĂ© en 1994, quand le mur de rimaye s'est couvert de dĂ©bris organiques et minĂ©raux. Il en a rĂ©sultĂ© que l'alimentation en eau de fonte venant de l'ablation du mur de rimaye a cessĂ©. Le changement dans les conditions environnementales dĂ» Ă la stabilisation du mur a dĂ©tournĂ© la succession vĂ©gĂ©tale de la chronosĂ©quence Ă©tablie en 1987. Des zones qui Ă©taient marĂ©cageuses en 1987 se sont assĂ©chĂ©es, et une Ă©tendue oĂč dominait Polygonum alaskanum apparue prĂšs du mur. En 1997, une grande partie de la zone du dĂ©crochement de fonte Ă©tait dominĂ©e par des espĂšces Salix, plutĂŽt qu'Equisteum, comme c'Ă©tait le cas en 1987. Toutefois, le sol situĂ© Ă plus de 200 m du mur de rimaye, sol vieux de dix ans en 1987, a subi moins de changement dans les conditions Ă©daphiques, et les communautĂ©s y ont continuĂ© Ă Ă©voluer vers une structure qui se rapproche de la forĂȘt non perturbĂ©e situĂ©e Ă la pĂ©riphĂ©rie
How do I sound to me? Perceived changes in communication in Parkinson's disease
Objective: To examine self and carer perceived changes in communication associated with Parkinson's disease and relate these to speech intelligibility, gender, age and other disease measures.
Design: Cross-sectional survey of a hospital- and community-based sample of 176 people with Parkinson's disease and their carers using a questionnaire based on semantic differential techniques.
Participants: One hundred and four people with Parkinson's disease with no history of communication difficulties prior to onset of their Parkinson's disease and 45 primary carers who returned completed questionnaires.
Main outcome measures: Differences in ratings for `before' the onset of Parkinson's disease versus present status.
Results: There was a strong perception of negative impact on communication between `before' and `now', irrespective of age and gender and largely independent of disease severity and duration, intelligibility and cognitive status. Activities of daily living (assessed by Unified Parkinson's Disease Rating Scale (UPDRS) II) and depression rating scale scores had the strongest association with change (adjusted R 2 0.27). There was a significant correlation between the rank order of perceived change in features examined in people with Parkinson's disease versus their carers, though in general carers rated change as having less impact.
Conclusions: Parkinson's disease exercises a strong influence on communication even before apparent alterations to intelligibility or motor status
The Relationship between the UniProt Knowledgebase (UniProtKB) and the IntAct Molecular Interaction Databases
IntAct provides a freely available, open source database system and analysis tools for protein interaction data. All interactions are derived from literature curation or direct user submission and all experimental information relating to binary protein-protein
interactions is entered into the IntAct database by curators, via a web-based editor. Interaction information is added to the SUBUNIT comment and the RP line of the relevant publication within the UniProtKB entry. There may be a single INTERACTION comment present within a UniProtKB entry, which conveys information relevant to binary protein-protein interactions. This is automatically derived from the IntAct database and is updated on a triweekly basis. Interactions can be derived by any appropriate experimental method but must be confirmed by a second interaction if resulting from a single yeast2hybrid experiment. For large-scale experiments, interactions are considered if a high confidence score is assigned by the authors. The INTERACTION line contains a direct link to IntAct that provides detailed information for the experimental support. These lines are not changed manually and any discrepancy is reported to IntAct for updates. There is also a database crossreference line within the UniProtKB entry i.e.: DR IntAct _UniProtKB AC, which directs the user to additional interaction data for that molecule. 
UniProt is supported by grants from the National Institutes of Health, European Commission, Swiss Federal Government and PATRIC BRC.
IntAct is funded by the European Commission under FELICS, contract number 021902 (RII3) within the Research Infrastructure Action of the FP6 "Structuring the European Research Area" Programme
A Radio Polarimetric Study of the Galactic Center Threads
Multi-frequency, polarimetric VLA observations of the non-thermal filaments
(NTF's), G0.08+0.15, and G359.96+0.09, also known as the Northern and Southern
Threads are presented at 20, 6, 3.6 and 2 cm, with high enough spatial
resolution to be resolved for the first time at 6 and 3.6 cm. The 20 cm image
reveals a wealth of new detail in the radio sources lying within the inner 60
pc of the Galaxy. The Southern Thread has a prominent split along its length,
similar to splitting at the ends of previously studied NTF's. With resolutions
as fine as 2'', the 3.6 and 6 cm images reveal a high degree of continuity and
little substructure internal to the filament. The spectral index of the
Northern Thread has been determined over a broad range of frequencies. Its flux
density falls with frequency, alpha=-0.5 between 90 and 6 cm, and becomes much
steeper (alpha=-2.0) between 6 and 2 cm. The spectral index does not vary
significantly along the length of the Northern Thread, which implies either
that the diffusion timescale for the emitting electrons is less than their
synchrotron lifetime, or that the emitting electrons are reaccelerated
continuously at multiple positions along the filament. Because of the lack of
spectral index variation, we have not located the source of relativistic
electrons. Polarization observations at 6 and 3.6 cm confirm the non-thermal
nature of the emission from the Northern Thread. The fractional polarization in
the Northern Thread reaches 70% in some regions, although the polarized
emission is patchy. Large rotation measures (RM > 2000 rad/m2) have been
observed with irregular variations across the filament.The intrinsic magnetic
field in the Northern Thread is predominantly aligned along its long axis.Comment: 19 pages, incl. 24 figs; to appear in the Astrophysical Journa
Review of the evidence of sentience in cephalopod molluscs and decapod crustaceans
Sentience is the capacity to have feelings, such as feelings of pain, pleasure, hunger, thirst, warmth, joy, comfort and excitement. It is not simply the capacity to feel pain, but feelings of pain, distress or harm, broadly understood, have a special significance for animal welfare law. Drawing on over 300 scientific studies, we have evaluated the evidence of sentience in two groups of invertebrate animals: the cephalopod molluscs or, for short, cephalopods (including octopods, squid and cuttlefish) and the decapod crustaceans or, for short, decapods (including crabs, lobsters and crayfish). We have also evaluated the potential welfare implications of current commercial practices involving these animals
NON-FREE VORTEX FLOW EFFECTS IN AN AXIAL FLOW ROTOR
This paper presents the analysis of three-dimensional flow field developing through an industrial
axial flow fan rotor of non-free vortex design carried out on the basis of concerted experimental and
numerical investigations. The paper focuses on non-free vortex flow effects requiring
consideration in rotor blade design theories. The distortion of stream surfaces through the blading
has been observed and a quantitative analysis of its effects on the blade loading condition has been
carried out in the through-flow core region. The streamlines close to the blades have been modelled
fitting to outward and inward conical stream tubes on the blade suction and pressure sides,
respectively - termed `cone couple modelÂŽ. It has been pointed out that the
blade lift can be
satisfactorily described at midspan on the basis of the cone couple model, with
use of pitch-averaged flow data. The loading aspects of the tested axial rotor have been discussed on the basis of
both the pressure distribution in the vicinity of the blades and pitch-averaged flow data obtained
upstream and downstream of the rotor. Sample calculations suggested that separate optimisation of
the blade suction and pressure sides is essential if the three-dimensional blade-to-blade flow is
intended to be considered in NFV fan design with use of two-dimensional cascade data
- âŠ