1,406 research outputs found
On the role of different Skyrme forces and surface corrections in exotic cluster-decay
We present cluster decay studies of Ni formed in heavy-ion
collisions using different Skyrme forces. Our study reveals that different
Skyrme forces do not alter the transfer structure of fractional yields
significantly. The cluster decay half-lives of different clusters lies within
\pm 10% for PCM and \pm 15% for UFM.Comment: 13 pages,6 figures and 1 table; in press Pramana Journal of Physics
(2010
Equality of Participation Online Versus Face to Face: Condensed Analysis of the Community Forum Deliberative Methods Demonstration
Online deliberation may provide a more cost-effective and/or less inhibiting
environment for public participation than face to face (F2F). But do online
methods bias participation toward certain individuals or groups? We compare F2F
versus online participation in an experiment affording within-participants and
cross-modal comparisons. For English speakers required to have Internet access
as a condition of participation, we find no negative effects of online modes on
equality of participation (EoP) related to gender, age, or educational level.
Asynchronous online discussion appears to improve EoP for gender relative to
F2F. Data suggest a dampening effect of online environments on black
participants, as well as amplification for whites. Synchronous online voice
communication EoP is on par with F2F across individuals. But individual-level
EoP is much lower in the online forum, and greater online forum participation
predicts greater F2F participation for individuals. Measured rates of
participation are compared to self-reported experiences, and other findings are
discussed.Comment: 14 pages, 10 tables, to appear in Efthimios Tambouris, Panos
Panagiotopoulos, {\O}ystein S{\ae}b{\o}, Konstantinos Tarabanis, Michela
Milano, Theresa Pardo, and Maria Wimmer (Editors), Electronic Participation:
Proceedings of the 7th IFIP WG 8.5 International Conference, ePart 2015
(Thessaloniki, August 30-September 2), Springer LNCS Vol. 9249, 201
A direct image of the obscuring disk surrounding an active galactic nucleus
Active galactic nuclei (AGN) are generally accepted to be powered by the
release of gravitational energy in a compact accretion disk surrounding a
massive black hole. Such disks are also necessary to collimate powerful radio
jets seen in some AGN. The unifying classification schemes for AGN further
propose that differences in their appearance can be attributed to the opacity
of the accreting material, which may obstruct our view of the central region of
some systems. The popular model for the obscuring medium is a parsec-scale disk
of dense molecular gas, although evidence for such disks has been mostly
indirect, as their angular size is much smaller than the resolution of
conventional telescopes. Here we report the first direct images of a pc-scale
disk of ionised gas within the nucleus of NGC 1068, the archetype of obscured
AGN. The disk is viewed nearly edge-on, and individual clouds within the
ionised disk are opaque to high-energy radiation, consistent with the unifying
classification scheme. In projection, the disk and AGN axes align, from which
we infer that the ionised gas disk traces the outer regions of the long-sought
inner accretion disk.Comment: 14 pages, LaTeX, PSfig, to appear in Nature. also available at
http://hethp.mpe-garching.mpg.de/Preprint
Fake people, real effects : the presence of virtual onlookers can impair performance and learning
Can effects of social influence be elicited in virtual contexts, and if so, under which conditions can they be observed? Answering these questions has theoretical merit, as the answers can help broaden our understanding of the interaction mechanisms described by social psychology. The increasing popularity of immersive media in training applications, however, has made these questions of practical significance. Virtual reality (VR), in particular, is a weapon of choice in designing training and education simulations, as it can be used to generate highly realistic characters and environments. As a consequence, it is key to understand under which circumstances virtual ‘others’ can facilitate or impede performance and – especially – learning. In this study, we investigated the impact of virtual onlookers on an adapted Serial Reaction Time (SRT) task that was presented in VR. In each trial, participants responded to a series of spherical stimuli by tapping them with handheld controllers when they lit up. Depending on the experiment block, the sequence order was either the permutation of a fixed order (and therefore predictable given the first stimulus), or fully random (and therefore unpredictable). Participants were divided into three groups (audience variable), depending on the environment in which the task was set: a group without onlookers (none condition), a group with a computer-generated audience (CGI condition), and a group being watched by a prerecorded audience (filmed condition). Results showed that the presence of a virtual audience can hamper both overall performance and learning, particularly when the audience appears more realistic. This study further reinforces the notion that the effects of social influence transcend the physical presence of others, but rather extend to virtual audiences
Magnetic support of the optical emission line filaments in NGC 1275
The giant elliptical galaxy NGC 1275, at the centre of the Perseus cluster,
is surrounded by a well-known giant nebulosity of emission-line filaments,
which are plausibly about >10^8 yr old. The filaments are dragged out from the
centre of the galaxy by the radio bubbles rising buoyantly in the hot
intracluster gas before later falling back. They act as dramatic markers of the
feedback process by which energy is transferred from the central massive black
hole to the surrounding gas. The mechanism by which the filaments are
stabilized against tidal shear and dissipation into the surrounding 4x10^7 K
gas has been unclear. Here we report new observations that resolve thread-like
structures in the filaments. Some threads extend over 6 kpc, yet are only 70 pc
wide. We conclude that magnetic fields in the threads, in pressure balance with
the surrounding gas, stabilize the filaments, so allowing a large mass of cold
gas to accumulate and delay star formation.Comment: Published in Nature, includes supplementary information, high
resolution images available at http://www-xray.ast.cam.ac.uk/papers/ngc1275
Framework, principles and recommendations for utilising participatory methodologies in the co-creation and evaluation of public health interventions
Background:
Due to the chronic disease burden on society, there is a need for preventive public health interventions to stimulate society towards a healthier lifestyle. To deal with the complex variability between individual lifestyles and settings, collaborating with end-users to develop interventions tailored to their unique circumstances has been suggested as a potential way to improve effectiveness and adherence. Co-creation of public health interventions using participatory methodologies has shown promise but lacks a framework to make this process systematic. The aim of this paper was to identify and set key principles and recommendations for systematically applying participatory methodologies to co-create and evaluate public health interventions.
Methods:
These principles and recommendations were derived using an iterative reflection process, combining key learning from published literature in addition to critical reflection on three case studies conducted by research groups in three European institutions, all of whom have expertise in co-creating public health interventions using different participatory methodologies.
Results:
Key principles and recommendations for using participatory methodologies in public health intervention co-creation are presented for the stages of: Planning (framing the aim of the study and identifying the appropriate sampling strategy); Conducting (defining the procedure, in addition to manifesting ownership); Evaluating (the process and the effectiveness) and Reporting (providing guidelines to report the findings). Three scaling models are proposed to demonstrate how to scale locally developed interventions to a population level.
Conclusions:
These recommendations aim to facilitate public health intervention co-creation and evaluation utilising participatory methodologies by ensuring the process is systematic and reproducible
A novel malaria vaccine candidate antigen expressed in Tetrahymena thermophila
Development of effective malaria vaccines is hampered by the problem of producing correctly folded Plasmodium proteins for use as vaccine components. We have investigated the use of a novel ciliate expression system, Tetrahymena thermophila, as a P. falciparum vaccine antigen platform. A synthetic vaccine antigen composed of N-terminal and C-terminal regions of merozoite surface protein-1 (MSP-1) was expressed in Tetrahymena thermophila. The recombinant antigen was secreted into the culture medium and purified by monoclonal antibody (mAb) affinity chromatography. The vaccine was immunogenic in MF1 mice, eliciting high antibody titers against both N- and C-terminal components. Sera from immunized animals reacted strongly with P. falciparum parasites from three antigenically different strains by immunofluorescence assays, confirming that the antibodies produced are able to recognize parasite antigens in their native form. Epitope mapping of serum reactivity with a peptide library derived from all three MSP-1 Block 2 serotypes confirmed that the MSP-1 Block 2 hybrid component of the vaccine had effectively targeted all three serotypes of this polymorphic region of MSP-1. This study has successfully demonstrated the use of Tetrahymena thermophila as a recombinant protein expression platform for the production of malaria vaccine antigens
The breast feeding mother and xenon anaesthesia: four case reports. Breast feeding and xenon anaesthesia
<p>Abstract</p> <p>Background</p> <p>Four nursing mothers consented to anaesthesia for urgent surgery only on condition that their ability to breast feed would not be impaired.</p> <p>Methods</p> <p>Following induction of general anaesthesia with propofol and remifentanil, 65-69% xenon supplemented with remifentanil was used as an inhalational anaesthetic for maintenance.</p> <p>Results</p> <p>After finishing surgery the women could be extubated between 2:52 and 7:22 minutes. The women were fully alert just minutes after extubation and spent about 45 minutes in the recovery room before discharge to a regular ward. They resumed regular breast feeding some time later. The propofol concentration in the blood was measured after 0, 30, 90, and 300 minutes and in the milk after 90 and 300 minutes. Just 90 minutes after extubation, the concentration of propofol in the milk was limited (> 3 mg/l) so that pharmacological effects on the babies were excluded after oral intake. Also, no traces of xenon gas were found in the maternal milk at any time. After propofol induction and maintenance of anaesthesia with xenon in combination with a water-soluble short-acting drug like remifentanil, the concentration of propofol in maternal milk is low (> 3 mg/l 90 min after anesthesia) and harmless after oral intake.</p> <p>Conclusions</p> <p>These results, as well as the rapid elimination and absence of metabolism of xenon, are of great interest to nursing mothers. General anaesthesia with propofol for induction only, combined with remifentanil and xenon for maintenance, has not yet been described in breast feeding mothers.</p
The Dynamical Structure and Evolution of Giant Molecular Clouds
Giant molecular clouds (GMCs) are the sites of star formation in the Galaxy. Many of their properties can be understood in terms of a model in which the GMCs and the star-forming clumps within them are in approximate pressure equilibrium, with turbulent motions treated as a separate pressure component
Pichinde virus induces microvascular endothelial cell permeability through the production of nitric oxide
This report is the first to demonstrate infection of human endothelial cells by Pichinde virus (PIC). PIC infection induces an upregulation of the inducible nitric oxide synthase gene; as well as an increase in detectable nitric oxide (NO). PIC induces an increase in permeability in endothelial cell monolayers which can be abrogated at all measured timepoints with the addition of a nitric oxide synthase inhibitor, indicating a role for NO in the alteration of endothelial barrier function. Because NO has shown antiviral activity against some viruses, viral titer was measured after addition of the NO synthase inhibitor and found to have no effect in altering virus load in infected EC. The NO synthase inhibition also has no effect on levels of activated caspases induced by PIC infection. Taken together, these data indicate NO production induced by Pichinde virus infection has a pathogenic effect on endothelial cell monolayer permeability
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