2,292 research outputs found
Calibration of liquid argon and neon detectors with
We report results from tests of Kr, as a calibration
source in liquid argon and liquid neon. Kr atoms are
produced in the decay of Rb, and a clear Kr
scintillation peak at 41.5 keV appears in both liquids when filling our
detector through a piece of zeolite coated with Rb. Based on this
scintillation peak, we observe 6.0 photoelectrons/keV in liquid argon with a
resolution of 6% (/E) and 3.0 photoelectrons/keV in liquid neon with a
resolution of 19% (/E). The observed peak intensity subsequently decays
with the Kr half-life after stopping the fill, and we
find evidence that the spatial location of Kr atoms in
the chamber can be resolved. Kr will be a useful
calibration source for liquid argon and neon dark matter and solar neutrino
detectors.Comment: 7 pages, 12 figure
Rational bidding using reinforcement learning: an application in automated resource allocation
The application of autonomous agents by the provisioning and usage of computational resources is an attractive research field. Various methods and technologies in the area of artificial intelligence, statistics and economics are playing together to achieve i) autonomic resource provisioning and usage of computational resources, to invent ii) competitive bidding strategies for widely used market mechanisms and to iii) incentivize consumers and providers to use such market-based systems.
The contributions of the paper are threefold. First, we present a framework for supporting consumers and providers in technical and economic preference elicitation and the generation of bids. Secondly, we introduce a consumer-side reinforcement learning bidding strategy which enables rational behavior by the generation and selection of bids. Thirdly, we evaluate and compare this bidding strategy against a truth-telling bidding strategy for two kinds of market mechanisms – one centralized and one decentralized
Age-specific vaccine effectiveness of seasonal 2010/2011 and pandemic influenza A(H1N1) 2009 vaccines in preventing influenza in the United Kingdom
An analysis was undertaken to measure age-specific vaccine effectiveness (VE) of 2010/11 trivalent seasonal influenza vaccine (TIV) and monovalent 2009 pandemic influenza vaccine (PIV) administered in 2009/2010. The test-negative case-control study design was employed based on patients consulting primary care. Overall TIV effectiveness, adjusted for age and month, against confirmed influenza A(H1N1)pdm 2009 infection was 56% (95% CI 42–66); age-specific adjusted VE was 87% (95% CI 45–97) in <5-year-olds and 84% (95% CI 27–97) in 5- to 14-year-olds. Adjusted VE for PIV was only 28% (95% CI x6 to 51) overall and 72% (95% CI 15–91) in <5-year-olds. For confirmed influenza B infection, TIV effectiveness was 57% (95% CI 42–68) and in 5- to 14-year-olds 75% (95% CI 32–91). TIV provided moderate protection against the main circulating strains in 2010/2011, with higher protection in children. PIV administered during the previous season provided residual protection after 1 year, particularly in the <5 years age group
Cosmological neutrino bounds for non-cosmologists
I briefly review cosmological bounds on neutrino masses and the underlying
gravitational physics at a level appropriate for readers outside the field of
cosmology. For the case of three massive neutrinos with standard model
freezeout, the current 95% upper limit on the sum of their masses is 0.42 eV. I
summarize the basic physical mechanism making matter clustering such a
sensitive probe of massive neutrinos. I discuss the prospects of doing still
better in coming years using tools such as lensing tomography, approaching a
sensitivity around 0.03 eV. Since the lower bound from atmospheric neutrino
oscillations is around 0.05 eV, upcoming cosmological measurements should
detect neutrino mass if the technical and fiscal challenges can be met.Comment: 4 pages, 2 figs, in "Neutrino Physics", Proceedings of Nobel
Symposium 129, eds., L Bergstrom, O. Botner, P. Carlson, P. O. Hulth, and T.
Ohlsso
WHO-ISG collaboration on assistive technologies for healthy ageing-in-place:A round table discussion
Assistive Technology (AT) is used at various points in the lifespan by those coping with either short-term or long-term impairments, which can involve living with chronic conditions and/or comorbidities. In the case of older adults, AT can support or compensate for the functional or cognitive declines that they are likely to face in later life. AT can be integrated as part of smart homes (see Figure 1 from van Dijken et al, 2006); and should be safe to use, effective, easy to access, affordable, and not seen as stigmatising. In addition, AT should support older adults to have a meaningful life while building self-esteem, and autonomy and promoting social participation and community engagement. For this roundtable discussion, we present and discuss a WHO-ISG collaborative project focused on Assistive Technology for Healthy Ageing. For this project, we consider applications and use AT not only from a medical standpoint but also situated within a social perspective in the context of Gerontechnology. Results and propositions according to the WHO-UNICEF global report on assistive technology were applied as a starting point for this project (WHO, 2022), prioritising the potential benefits to individuals, their communities, and society and with a focus on identifying potential barriers that may occur and how to mitigate them
Place attachment in deprived neighbourhoods: The impacts of population turnover and social mix
This paper examines the determinants of individual place attachment, focussing in particular on differences between deprived and others neighbourhoods, and on the impacts of population turnover and social mix. It uses a multi-level modelling approach to take account of both individual- and neighbourhood-level determinants. Data are drawn from a large sample government survey, the Citizenship Survey 2005, to which a variety of neighbourhood-level data have been attached. The paper argues that attachment is significantly lower in more deprived neighbourhoods primarily because these areas have weaker social cohesion but that, in other respects, the drivers of attachment are the same. Turnover has modest direct impacts on attachment through its effect on social cohesion. Social mix has very limited impacts on attachment and the effects vary between social groups. In general, higher status or more dominant groups appear less tolerant of social mix
Preparation, imaging, and quantification of bacterial surface motility assays.
Publication fees for this article were partially sponsored by Bruker Corporation.International audienceBacterial surface motility, such as swarming, is commonly examined in the laboratory using plate assays that necessitate specific concentrations of agar and sometimes inclusion of specific nutrients in the growth medium. The preparation of such explicit media and surface growth conditions serves to provide the favorable conditions that allow not just bacterial growth but coordinated motility of bacteria over these surfaces within thin liquid films. Reproducibility of swarm plate and other surface motility plate assays can be a major challenge. Especially for more "temperate swarmers" that exhibit motility only within agar ranges of 0.4%-0.8% (wt/vol), minor changes in protocol or laboratory environment can greatly influence swarm assay results. "Wettability", or water content at the liquid-solid-air interface of these plate assays, is often a key variable to be controlled. An additional challenge in assessing swarming is how to quantify observed differences between any two (or more) experiments. Here we detail a versatile two-phase protocol to prepare and image swarm assays. We include guidelines to circumvent the challenges commonly associated with swarm assay media preparation and quantification of data from these assays. We specifically demonstrate our method using bacteria that express fluorescent or bioluminescent genetic reporters like green fluorescent protein (GFP), luciferase (lux operon), or cellular stains to enable time-lapse optical imaging. We further demonstrate the ability of our method to track competing swarming species in the same experiment
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