165 research outputs found
A visual programming model to implement coarse-grained DSP applications on parallel and heterogeneous clusters
International audienceThe digital signal processing (DSP) applications are one of the biggest consumers of computing. They process a big data volume which is represented with a high accuracy. They use complex algorithms, and must satisfy a time constraints in most of cases. In the other hand, it's necessary today to use parallel and heterogeneous architectures in order to speedup the processing, where the best examples are the su-percomputers "Tianhe-2" and "Titan" from the top500 ranking. These architectures could contain several connected nodes, where each node includes a number of generalist processor (multi-core) and a number of accelerators (many-core) to finally allows several levels of parallelism. However, for DSP programmers, it's still complicated to exploit all these parallelism levels to reach good performance for their applications. They have to design their implementation to take advantage of all heteroge-neous computing units, taking into account the architecture specifici-ties of each of them: communication model, memory management, data management, jobs scheduling and synchronization . . . etc. In the present work, we characterize DSP applications, and based on their distinctive-ness, we propose a high level visual programming model and an execution model in order to drop down their implementations and in the same time make desirable performances
Not âjust a bad periodââ The impact of a co-created endometriosis social media health campaign: a mixed methods study
Objective: The goal of this study was to evaluate the impact of a visual social media health campaign. The #1in10 campaign was co-created by the Danish Endometriosis Patient Association and women with endometriosis.
Methods: Seven semi-structured interviews were conducted with campaign participants to evaluate their experience of participating. The interviews were then analyzed thematically. Social media metrics on the reach of the campaign were gathered to assess how the campaign had performed.
Results: Seven themes were identified in the interviews: (1) Taboo, (2) Visibility, (3) Awareness, (4) Acknowledgment, (5) Empowerment, (6) Patient Experts, and (7) Community. Throughout the interviews, the women conveyed that they found their participation in the campaign meaningful, as it contributed to creating awareness and recognition of a disease otherwise surrounded by taboo and stigma. Social media metrics show how the #1in10 campaign reached both people inside and outside the endometriosis community. Across the FEMaLe Project's three social media platforms, 208 (51.5%) of engagements were with patients with endometriosis, 96 (23.7%) were with FEMaLe employees and advisers, 94 (23.3%) were with the general public, and 6 (1.5%) were with policymakers. In the month the #1in10 campaign was released, the FEMaLe Project's Twitter and Instagram accounts had more impressions than almost any other month that year (except January on Twitter and November on Instagram). The FEMaLe Project's LinkedIn had the same number of impressions as in other months.
Discussion: The study shows that the #1in10 social media campaign had an impact on three levels: on an individual level for the participating patients, on a communal level for people with endometriosis, and on a wider societal level. The participating patients felt empowered by their involvement with the campaign and the act of coming forward. The participants acted on behalf of their community of people with endometriosis, in the hopes that it would raise awareness and acknowledgment. In return, the community engaged with the campaign and added significantly to the dissemination of its message. On a societal level the campaign has caught particular attention and engagement compared to other posts made on the same social media accounts. Combining qualitative and quantitative methods, this study has demonstrated that the #1in10 campaign had an impact on three different levels: individual, communal, and societal. On an individual level the campaign fostered empowerment for the participating women, because they felt that their participation contributed to making their struggles visible, known, and acknowledged. The participants took part in the campaign on behalf of their community of people with endometriosis, in the hopes that their activistic actions would benefit future members of the community. That the campaign resonated with the community is evident by the fact that 51.5% (N = 208) of the engagement with the campaign was made by members of the community. As such, the community was vital for both the creation and the dissemination of the campaign. The #1in10 campaign performed comparatively well with regards to creating engagements on social media- not just within the community but also in the wider society. While this does not necessarily entail a change in attitude or behavior, it suggests that the co-created and visual nature of the campaign had an impact on the audience
Classical stability of U(1)_A domain walls in dense matter QCD
It was recently shown that there exists metastable U(1)_A domain wall
configurations in high-density QCD (\mu >> 1 GeV). In the following we will
assess the stability of such non-trivial field configurations at intermediate
densities (\mu < 1 GeV). The existence of such configurations at intermediate
densities could have interesting consequences for the physics of neutron stars
with high core density.Comment: 13 pages, 2 Postscript figures, typos correcte
Drum vortons in high density QCD
Recently it was shown that high density QCD supports of number of topological
defects. In particular, there are U(1)_Y strings that arise due to K^0
condensation that occurs when the strange quark mass is relatively large. The
unique feature of these strings is that they possess a nonzero K^+ condensate
that is trapped on the core. In the following we will show that these strings
(with nontrivial core structure) can form closed loops with conserved charge
and currents trapped on the string worldsheet. The presence of conserved
charges allows these topological defects, called vortons, to carry angular
momentum, which makes them classically stable objects. We also give arguments
demonstrating that vortons carry angular momentum very efficiently (in terms of
energy per unit angular momentum) such that they might be the important degrees
of freedom in the cores of neutron stars.Comment: 11 pages, accepted for publication in Physical Review
Fermi acceleration in astrophysical jets
We consider the acceleration of energetic particles by Fermi processes (i.e.,
diffusive shock acceleration, second order Fermi acceleration, and gradual
shear acceleration) in relativistic astrophysical jets, with particular
attention given to recent progress in the field of viscous shear acceleration.
We analyze the associated acceleration timescales and the resulting particle
distributions, and discuss the relevance of these processes for the
acceleration of charged particles in the jets of AGNs, GRBs and microquasars,
showing that multi-component powerlaw-type particle distributions are likely to
occur.Comment: 6 pages, one figure; based on talk at "The multimessenger approach to
unidentified gamma-ray sources", Barcelona/Spain, July 2006; accepted for
publication in Astrophysics and Space Scienc
Identification of a novel inflamed tumor microenvironment signature as a predictive biomarker of bacillus Calmette-Guérin immunotherapy in non-muscle-invasive bladder cancer
Purpose: Improved risk stratification and predictive biomarkers of treatment response are needed for non-muscle-invasive bladder cancer (NMIBC). Here we assessed the clinical utility of targeted RNA and DNA molecular profiling in NMIBC. Experimental Design: Gene expression in NMIBC samples was profiled by NanoString nCounter, an RNA quantification platform, from two independent cohorts (n = 28, n = 50); targeted panel sequencing was performed in a subgroup (n = 50). Gene signatures were externally validated using two RNA sequencing datasets of NMIBC tumors (n = 438, n = 73). Established molecular subtype classifiers and novel gene expression signatures were assessed for associations with clinicopathologic characteristics, somatic tumor mutations, and treatment outcomes. Results: Molecular subtypes distinguished between low-grade Ta tumors with FGFR3 mutations and overexpression (UROMOL-class 1) and tumors with more aggressive clinicopathologic characteristics (UROMOL-classes 2 and 3), which were significantly enriched with TERT promoter mutations. However, UROMOL subclasses were not associated with recurrence after bacillus Calmette-GuĂ©rin (BCG) immunotherapy in two independent cohorts. In contrast, a novel expression signature of an inflamed tumor microenvironment (TME) was associated with improved recurrence-free survival after BCG. Expression of immune checkpoint genes (PD-L1/PD-1/CTLA-4) was associated with an inflamed TME, but not with higher recurrence rates after BCG. FGFR3 mutations and overexpression were both associated with low immune signatures. Conclusions: Assessment of the immune TME, rather than molecular subtypes, is a promising predictive biomarker of BCG response. Modulating the TME in an immunologically âcoldâ tumor warrants further investigation. Integrated transcriptomic and exome sequencing should improve treatment selection in NMIBC
Topical Issues for Particle Acceleration Mechanisms in Astrophysical Shocks
Particle acceleration at plasma shocks appears to be ubiquitous in the
universe, spanning systems in the heliosphere, supernova remnants, and
relativistic jets in distant active galaxies and gamma-ray bursts. This review
addresses some of the key issues for shock acceleration theory that require
resolution in order to propel our understanding of particle energization in
astrophysical environments. These include magnetic field amplification in shock
ramps, the non-linear hydrodynamic interplay between thermal ions and their
extremely energetic counterparts possessing ultrarelativistic energies, and the
ability to inject and accelerate electrons in both non-relativistic and
relativistic shocks. Recent observational developments that impact these issues
are summarized. While these topics are currently being probed by
astrophysicists using numerical simulations, they are also ripe for
investigation in laboratory experiments, which potentially can provide valuable
insights into the physics of cosmic shocks.Comment: 13 pages, no figures. Invited review, accepted for publication in
Astrophysics and Space Science, as part of the HEDLA 2006 conference
proceeding
Particle acceleration mechanisms
We review the possible mechanisms for production of non-thermal electrons
which are responsible for non-thermal radiation in clusters of galaxies. Our
primary focus is on non-thermal Bremsstrahlung and inverse Compton scattering,
that produce hard X-ray emission. We briefly review acceleration mechanisms and
point out that in most astrophysical situations, and in particular for the
intracluster medium, shocks, turbulence and plasma waves play a crucial role.
We consider two scenarios for production of non-thermal radiation. The first is
hard X-ray emission due to non-thermal Bremsstrahlung by nonrelativistic
particles. Non-thermal tails are produced by accelerating electrons from the
background plasma with an initial Maxwellian distribution. However, these tails
are accompanied by significant heating and they are present for a short time of
<10^6 yr, which is also the time that the tail will be thermalised. Such
non-thermal tails, even if possible, can only explain the hard X-ray but not
the radio emission which needs GeV or higher energy electrons. For these and
for production of hard X-rays by the inverse Compton model, we need the second
scenario where there is injection and subsequent acceleration of relativistic
electrons. It is shown that a steady state situation, for example arising from
secondary electrons produced from cosmic ray proton scattering by background
protons, will most likely lead to flatter than required electron spectra or it
requires a short escape time of the electrons from the cluster. An episodic
injection of relativistic electrons, presumably from galaxies or AGN, and/or
episodic generation of turbulence and shocks by mergers can result in an
electron spectrum consistent with observations but for only a short period of
less than one billion years.Comment: 22 pages, 5 figures, accepted for publication in Space Science
Reviews, special issue "Clusters of galaxies: beyond the thermal view",
Editor J.S. Kaastra, Chapter 11; work done by an international team at the
International Space Science Institute (ISSI), Bern, organised by J.S.
Kaastra, A.M. Bykov, S. Schindler & J.A.M. Bleeke
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