9,088 research outputs found
Simulations of Nonthermal Electron Transport in Multidimensional Flows: Synthetic Observations of Radio Galaxies
We have applied an effective numerical scheme for cosmic-ray transport to 3D
MHD simulations of jet flow in radio galaxies (see the companion paper by Jones
et al. 1999). The marriage of relativistic particle and 3D magnetic field
information allows us to construct a rich set of ``synthetic observations'' of
our simulated objects. The information is sufficient to calculate the ``true''
synchrotron emissivity at a given frequency using explicit information about
the relativistic electrons. This enables us to produce synchrotron
surface-brightness maps, including polarization. Inverse-Compton X-ray
surface-brightness maps may also be produced. First results intended to explore
the connection between jet dynamics and electron transport in radio lobes are
discussed. We infer lobe magnetic field values by comparison of synthetically
observed X-ray and synchrotron fluxes, and find these ``inverse-Compton''
fields to be quite consistent with the actual RMS field averaged over the lobe.
The simplest minimum energy calculation from the synthetic observations also
seems to agree with the actual simulated source properties.Comment: 7 pages, 1 figure; to appear in Life Cycles of Radio Galaxies, ed. J.
Biretta et al., New Astronomy Review
Doing interdisciplinarity: motivation and collaboration in research for sustainable agriculture in the UK
This paper studies knowledge production in complex, collaborative research projects which brought together academics of different disciplines, research users and agricultural businesses. It takes a comparative approach, studying the interactions within interdisciplinary research teams from 10 case studies, considering the process of collaboration from initial idea through to publication. The research developed a typology of participants in these projects, and identified the motivations and challenges of each. Our results analyse the process of research teams coming together and the relationships which are built up during the research. A particular challenge identified was the building of cooperation and trust. This issue is explored alongside issues of communication, methodology, data analysis and the process of drawing and publicising conclusions
Linearizability with Ownership Transfer
Linearizability is a commonly accepted notion of correctness for libraries of
concurrent algorithms. Unfortunately, it assumes a complete isolation between a
library and its client, with interactions limited to passing values of a given
data type. This is inappropriate for common programming languages, where
libraries and their clients can communicate via the heap, transferring the
ownership of data structures, and can even run in a shared address space
without any memory protection. In this paper, we present the first definition
of linearizability that lifts this limitation and establish an Abstraction
Theorem: while proving a property of a client of a concurrent library, we can
soundly replace the library by its abstract implementation related to the
original one by our generalisation of linearizability. This allows abstracting
from the details of the library implementation while reasoning about the
client. We also prove that linearizability with ownership transfer can be
derived from the classical one if the library does not access some of data
structures transferred to it by the client
Case study reducing pesticide residues on horticultural crops
"Production and export of horticultural products are increasing rapidly in many developing countries... Rapid growth in horticultural production has been accompanied by heavy use of pesticides and by heightened concern over health effects associated with pesticide use and abuse...The three examples [in this study] demonstrate how applied research to support IPM can reduce pesticide use, residues, and export barriers." from TextFood safety ,food security ,Public health ,
Learning and research for sustainable agro-ecosystems by both farmers and scientists.
This research explored how farming businesses learn, make decisions, benchmark and carry out their own informal experimentation to find the system that meet their needs and their local ecological context. The research also examined how farming businesses and scientific researchers can collaborate.
This required a greater understanding amongst scientists and between scientists and businesses, recognising each other's strengths and weaknesses and finding ways of working together. This interdisciplinary subject will be examined by a team of social, environmental and biological researchers, examining ten cases of farmer researcher collaboration with the aim of identifying good practice in interdisciplinary research on agro ecosystems in UK agriculture
Developing a partcipatory approach to seed production and varietal selection
The performance of UK winter wheat varieties was tested under organic conditions involving farmer participation. Three breadmaking varieties (Hereward, Solstice and Xi19) and their mixture (1:1:1) were grown at 19 UK farms in 2003/04 and 2004/05. The variability of productivity on organic farms was illustrated with more variation among farm sites than among varieties. Seed health was generally high over all sites. Although the trials were successful, more time was needed at project initiation to improve farmer involvement. Some farmers expected more researcher visits, and were reticent about assessing the trials themselves. In contrast, some participants valued the variety performance data on their farms particularly when related to that of other growers. The balance between the goals of the researchers relative to the farmers needs to be defined at project initiation
Extreme star formation events in quasar hosts over
We explore the relationship between active galactic nuclei and star formation
in a sample of 513 optically luminous type 1 quasars up to redshifts of 4
hosting extremely high star formation rates (SFRs). The quasars are selected to
be individually detected by the \textit{Herschel} SPIRE instrument at 3 at 250 m, leading to typical SFRs of order of 1000
Myr. We find the average SFRs to increase by almost a factor
10 from to , mirroring the rise in the comoving SFR density
over the same epoch. However, we find that the SFRs remain approximately
constant with increasing accretion luminosity for accretion luminosities above
10 L. We also find that the SFRs do not correlate with black
hole mass. Both of these results are most plausibly explained by the existence
of a self-regulation process by the starburst at high SFRs, which controls SFRs
on time-scales comparable to or shorter than the AGN or starburst duty cycles.
We additionally find that SFRs do not depend on Eddington ratio at any
redshift, consistent with no relation between SFR and black hole growth rate
per unit black hole mass. Finally, we find that high-ionisation broad
absorption line (HiBAL) quasars have indistinguishable far-infrared properties
to those of classical quasars, consistent with HiBAL quasars being normal
quasars observed along a particular line of sight, with the outflows in HiBAL
quasars not having any measurable effect on the star formation in their hosts.Comment: 12 pages, 6 figure
Seeing the body distorts tactile size perception
Vision of the body modulates somatosensation, even when entirely non-informative about stimulation. For example, seeing the body increases tactile spatial acuity, but reduces acute pain. While previous results demonstrate that vision of the body modulates somatosensory sensitivity, it is unknown whether vision also affects metric properties of touch, and if so how. This study investigated how non-informative vision of the body modulates tactile size perception. We used the mirror box illusion to induce the illusion that participants were directly seeing their stimulated left hand, though they actually saw their reflected right hand. We manipulated whether participants: (a) had the illusion of directly seeing their stimulated left hand, (b) had the illusion of seeing a non-body object at the same location, or (c) looked directly at their non-stimulated right-hand. Participants made verbal estimates of the perceived distance between two tactile stimuli presented simultaneously to the dorsum of the left hand, either 20, 30, or 40 mm apart. Vision of the body significantly reduced the perceived size of touch, compared to vision of the object or of the contralateral hand. In contrast, no apparent changes of perceived hand size were found. These results show that seeing the body distorts tactile size perception
Piments, ports et traçage des insectes et animaux nuisibles
Vu l'essor du marché du piment, la Jamaïque a développé un système dernier cri de traçabilité de l'incidence des insectes et animaux nuisibles pour que la cécidomyie ne lui ferme plus les portes du marché nord-américain
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