11,053 research outputs found
Compact steep-spectrum sources from the S4 sample
We present the results of 5-GHz observations with the VLA A-array of a sample
of candidate Compact Steep Spectrum sources (CSSs) selected from the S4 survey.
We also estimate the symmetry parameters of high-luminosity CSSs selected from
different samples of radio sources, and compare these with the larger sources
of similar luminosity to understand their evolution and the consistency of the
CSSs with the unified scheme for radio galaxies and quasars. The majority of
CSSs are likely to be young sources advancing outwards through a dense
asymmetric environment. The radio properties of CSSs are found to be consistent
with the unified scheme, in which the axes of the quasars are observed close to
the line of sight, while radio galaxies are observed close to the plane of the
sky.Comment: accepted for publication in mnras; 8 pages, figure 1 with 21 images,
and two additional figures; 2 table
The role of virtual reality in built environment education
This study builds upon previous research on the integration of Virtual Reality (VR) within the built environment curriculum and aims to investigate the role of VR and three-dimensional (3D) computer modelling on learning and teaching in a school of the built environment. In order to achieve this aim, a number of academic experiences were analysed to explore the applicability and viability of 3D computer modelling and VR into built environment subject areas. Although two-dimensional (2D) representations have been greatly accepted by built environment professions and education, 3D computer representations and VR applications, offering interactivity and immersiveness, are not yet widely accepted. The study attempts to understand the values and challenges of integrating visualisation technologies into built environment teaching and investigates tutors’ perceptions, opinions and concerns with respect to these technologies. The study reports on the integration process and considers how 3D computer modelling and VR technologies can combine with, and extend, the existing range of learning and teaching methods appropriate to different disciplines and programme areas
Influence of the extraction temperature on rheological properties of flaxseed gum solution
The 19th Gums & Stabilisers for the Food Industry Conference: Hydrocolloid multifunctionalityinfo:eu-repo/semantics/publishedVersio
Avaliação do sistema de camalhão em relação a três outros sistemas de preparo de solo para plantio de milho.
Energia requerida na construção de camalhões para plantio de milho em solos com deficiência de drenagem.
Double Lobed Radio Quasars from the Sloan Digital Sky Survey
We have combined a sample of 44984 quasars, selected from the Sloan Digital
Sky Survey (SDSS) Data Release 3, with the FIRST radio survey. Using a novel
technique where the optical quasar position is matched to the complete radio
environment within 450", we are able to characterize the radio morphological
make-up of what is essentially an optically selected quasar sample, regardless
of whether the quasar (nucleus) itself has been detected in the radio. About
10% of the quasar population have radio cores brighter than 0.75 mJy at 1.4
GHz, and 1.7% have double lobed FR2-like radio morphologies. About 75% of the
FR2 sources have a radio core (> 0.75 mJy). A significant fraction (~40%) of
the FR2 quasars are bent by more than 10 degrees, indicating either
interactions of the radio plasma with the ICM or IGM. We found no evidence for
correlations with redshift among our FR2 quasars: radio lobe flux densities and
radio source diameters of the quasars have similar distributions at low (mean
0.77) and high (mean 2.09) redshifts. Using a smaller high reliability FR2
sample of 422 quasars and two comparison samples of radio-quiet and non-FR2
radio-loud quasars, matched in their redshift distributions, we constructed
composite optical spectra from the SDSS spectroscopic data. Based on these
spectra we can conclude that the FR2 quasars have stronger high-ionization
emission lines compared to both the radio quiet and non-FR2 radio loud sources.
This is consistent with the notion that the emission lines are brightened by
ongoing shock ionization of ambient gas in the quasar host as the radio source
expands.Comment: 20 pages, 10 figures - some of which have been reduced in quality /
size. Accepted for publication in the Astronomical Journa
Geospatial web services pave new ways for server-based on-demand access and processing of Big Earth Data
Big Earth Data has experienced a considerable increase in volume in recent years due to improved sensing technologies and improvement of numerical-weather prediction models. The traditional geospatial data analysis workflow hinders the use of large volumes of geospatial data due to limited disc space and computing capacity. Geospatial web service technologies bring new opportunities to access large volumes of Big Earth Data via the Internet and to process them at server-side. Four practical examples are presented from the marine, climate, planetary and earth observation science communities to show how the standard interface Web Coverage Service and its processing extension can be integrated into the traditional geospatial data workflow.Web service technologies offer a time- and cost-effective way to access multi-dimensional data in a user-tailored format and allow for rapid application development or time-series extraction. Data transport is minimised and enhanced processing capabilities are offered. More research is required to investigate web service implementations in an operational mode and large data centres have to become more progressive towards the adoption of geo-data standard interfaces. At the same time, data users have to become aware of the advantages of web services and be trained how to benefit from them most
Avaliação dos danos mecânicos na colheita de milho de alta qualidade protéica (QPM).
A maioria dos genótipos de milho contém entre 9 e 10% de proteÃna, pobre em lisina e triptofano, os quais são dois aminoácidos essenciais. Com a descoberta de um gene mutante chamado Opaco, que modifica a composição da proteÃna, obteve-se um milho com alto teor de lisina e triptofano no endosperma branco, opaco e macio, sendo estas três últimas caracterÃsticas indesejáveis. através de ciclos avançados de seleção, obteve-se a variedade BR 2121 enriquecida dos aminoácidos essenciais, com endosperma de cor amarela, vÃtreo e semiduro. O objetivo do presente trabalho foi avaliar os danos mecânicos causados durante a colheita e debulha de cultivares de milho hÃbridos semiduros (BR 2121-QPM, "Quality Protein Maize" - milho de alta qualidade protéica e BR 3123 Normal) em duas faixas de umidade (14 16% E 16 a 18%) e quatro velocidades de rotação do cilindro debulhador (0, 500, 600 700 rpm). As espigas foram desbulhadas, utilizando-se uma colhedora-trilhadora modelo Nursey-master hidrostatic. As análises de determinação de germinação e vigor objetivaram informar sobre a qualidade das sementes, a fim de possibilitar a observação do comportamento dos grãos apos o processo de debulha (manual e mecânica). Em ambos cultivares foi observado um decréscimo da qualidade das sementes, porém mais acentuadas para a cultivar de alto valor protéico
In Situ Test Method for the Electrostatic Characterization of Lunar Dust
This paper serves to illustrate the testing methods necessary to classify the electrostatic properties of lunar dust using in situ instrumentation and the required techniques therein. A review of electrostatic classification of lunar simulant materials is provided as is its relevance to the success of future human lunar missions
A Study of 3CR Radio Galaxies from z = 0.15 to 0.65. II. Evidence for an Evolving Radio Structure
Radio structure parameters were measured from the highest quality radio maps
available for a sample of 3CR radio galaxies in the redshift range 0.15 < z <
0.65. Combined with similar data for quasars in the same redshift range, these
morphology data are used in conjunction with a quantification of the richness
of the cluster environment around these objects (the amplitude of the
galaxy-galaxy spatial covariance function, Bgg) to search for indirect evidence
of a dense intracluster medium (ICM). This is done by searching for confinement
and distortions of the radio structure that are correlated with Bgg.
Correlations between physical size and hot spot placement with Bgg show
evidence for an ICM only at z 0.4,
suggesting an epoch of z ~ 0.4 for the formation of an ICM in these Abell
richness class 0-1, FR2-selected clusters. X-ray selected clusters at
comparable redshifts, which contain FR1 type sources exclusively, are
demonstrably richer than the FR2-selected clusters found in this study. The
majority of the radio sources with high Bgg values at z < 0.4 can be described
as ``fat doubles'' or intermediate FR2/FR1s. The lack of correlation between
Bgg and bending angle or Bgg and lobe length asymmetry suggests that these
types of radio source distortion are caused by something other than interaction
with a dense ICM. Thus, a large bending angle cannot be used as an unambiguous
indicator of a rich cluster around powerful radio sources. These results
support the hypothesis made in Paper 1 that cluster quasars fade to become
FR2s, then FR1s, on a timescale of 0.9 Gyrs (for H0 = 50 km s^-1 Mpc^-1).Comment: 44 pages, 8 figures, 2 tables; to be published in the September 2002
issue of The Astronomical Journa
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