207,280 research outputs found
On the power of mediators
We consider a problem at the intersection of distributed computing and game theory, namely: Is it; possible to achieve the "windfall of malice" even without the actual presence of malicious players'? Our answer to this question is "Yes and No". Our positive result is that for the virus inoculation game, it is possible to achieve the windfall of malice by use of a mediator. Our negative result is that for symmetric congestion games that are known to have a windfall of malice, it is not possible to design a mediator that achieves this windfall. In proving these two results, we develop novel techniques for mediator design that we believe will be helpful for creating non-trivial mediators to improve social welfare in a large class of games.Postprint (published version
Rape and Posttraumatic Stress Disorder (PTSD): Examining the Mediating Role of Explicit Sex-Power Beliefs for Men Versus Women
Many rape survivors exhibit symptoms of post-traumatic stress disorder (PTSD), and recent literature suggests survivors\u27 beliefs about sex and control may affect PTSD symptoms. The present study examined beliefs about sex and power as potential mediators of the relationship between rape and PTSD symptoms for men versus women. Participants (N = 782) reported lifetime history of rape, current PTSD symptoms, and beliefs about sex and power. Women reported higher levels of lifetime history of rape than men (19.7% for women; 9.7% for men). While rape history predicted PTSD symptoms for both genders, beliefs about sex and power were shown to be a significant partial mediator of this relationship for men, but not for women. Results extend the literature on rape and PTSD by suggesting that survivors\u27 beliefs about sex and power are connected and can affect their PTSD symptoms. Additionally, results illustrate how sexual violence against men may reaffirm male gender roles that entail power and aggression, and ultimately affect trauma recovery
The Role of Natural Laccase Redox Mediators in Simultaneous Dye Decolorization and Power Production in Microbial Fuel Cells
Redox mediators could be used to improve the efficiency of microbial fuel cells (MFCs) by enhancing electron transfer rates and decreasing charge transfer resistance at electrodes. However, many artificial redox mediators are expensive and/or toxic. In this study, laccase enzyme was employed as a biocathode of MFCs in the presence of two natural redox mediators (syringaldehyde (Syr) and acetosyringone (As)), and for comparison, a commonly-used artificial mediator 2,2′-azinobis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) was used to investigate their influence on azo dye decolorization and power production. The redox properties of the mediator-laccase systems were studied by cyclic voltammetry. The presence of ABTS and As increased power density from 54.7 ± 3.5 mW m−2 (control) to 77.2 ± 4.2 mW m−2 and 62.5 ± 3.7 mW m−2 respectively. The power decreased to 23.2 ± 2.1 mW m−2 for laccase with Syr. The cathodic decolorization of Acid orange 7 (AO7) by laccase indicated a 12–16% increase in decolorization efficiency with addition of mediators; and the Laccase-Acetosyringone system was the fastest, with 94% of original dye (100 mgL−1) decolorized within 24 h. Electrochemical analysis to determine the redox properties of the mediators revealed that syringaldehyde did not produce any redox peaks, inferring that it was oxidized by laccase to other products, making it unavailable as a mediator, while acetosyringone and ABTS revealed two redox couples demonstrating the redox mediator properties of these compounds. Thus, acetosyringone served as an efficient natural redox mediator for laccase, aiding in increasing the rate of dye decolorization and power production in MFCs. Taken together, the results suggest that natural laccase redox mediators could have the potential to improve dye decolorization and power density in microbial fue
Imaging resonant dissipation from individual atomic defects in graphene
Conversion of electric current into heat involves microscopic processes that
operate on nanometer length-scales and release minute amounts of power. While
central to our understanding of the electrical properties of materials,
individual mediators of energy dissipation have so far eluded direct
observation. Using scanning nano-thermometry with sub-micro K sensitivity we
visualize and control phonon emission from individual atomic defects in
graphene. The inferred electron-phonon 'cooling power spectrum' exhibits sharp
peaks when the Fermi level comes into resonance with electronic quasi-bound
states at such defects, a hitherto uncharted process. Rare in the bulk but
abundant at graphene's edges, switchable atomic-scale phonon emitters define
the dominant dissipation mechanism. Our work offers new insights for addressing
key materials challenges in modern electronics and engineering dissipation at
the nanoscale
Continuum-Mediated Dark Matter-Baryon Scattering
Many models of dark matter scattering with baryons may be treated either as a
simple contact interaction or as the exchange of a light mediator particle. We
study an alternative, in which a continuum of light mediator states may be
exchanged. This could arise, for instance, from coupling to a sector which is
approximately conformal at the relevant momentum transfer scale. In the
non-relativistic effective theory of dark matter-baryon scattering, which is
useful for parametrizing direct detection signals, the effect of such continuum
mediators is to multiply the amplitude by a function of the momentum transfer
q, which in the simplest case is just a power law. We develop the basic
framework and study two examples: the case where the mediator is a scalar
operator coupling to the Higgs portal (which turns out to be highly
constrained) and the case of an antisymmetric tensor operator that mixes with the hypercharge field strength and couples to dark matter
tensor currents, which has an interesting viable parameter space. We describe
the effect of such mediators on the cross sections and recoil energy spectra
that could be observed in direct detection.Comment: 30 pages, 6 figures. v2: minor changes, references adde
Patients' empowerment through cultural mediators in healthcare settings
The purpose of the present dissertation has been to provide insights into the role of
cultural mediators in enhancing patients’ empowerment medical encounters. Specific
attention was paid to relations of power between mediators and heath staff
understood in terms of the attribution of value to resources of knowledge.
The research takes a linguistic ethnographic approach to examining mediation within
healthcare settings. Data-gathering techniques included recorded mediated
interactions, interviews with healthcare staff and mediators, observations, analysis of
hospital documents and visual material.
Findings show that mediators have a considerable impact on patients’ empowerment.
The data seems to confirm that mediators empower migrant patients in those cases
when patients seek information and express concerns. Nevertheless, the research
demonstrated that mediators prevent patients’ participation and maintain the status
quo of the healthcare system when patients make decisions and express refusals. The
findings demonstrate the need to implement training programmes for both healthcare
providers and mediators to become more aware of their role of coordinators in the
interaction. Additionally, there is a need for heath staff to attribute a higher value to
mediators’ cultural capital and the need for healthcare institutions to recognise
mediators as a professional group
Mechanisms for Outsourcing Computation via a Decentralized Market
As the number of personal computing and IoT devices grows rapidly, so does
the amount of computational power that is available at the edge. Since many of
these devices are often idle, there is a vast amount of computational power
that is currently untapped, and which could be used for outsourcing
computation. Existing solutions for harnessing this power, such as volunteer
computing (e.g., BOINC), are centralized platforms in which a single
organization or company can control participation and pricing. By contrast, an
open market of computational resources, where resource owners and resource
users trade directly with each other, could lead to greater participation and
more competitive pricing. To provide an open market, we introduce MODiCuM, a
decentralized system for outsourcing computation. MODiCuM deters participants
from misbehaving-which is a key problem in decentralized systems-by resolving
disputes via dedicated mediators and by imposing enforceable fines. However,
unlike other decentralized outsourcing solutions, MODiCuM minimizes
computational overhead since it does not require global trust in mediation
results. We provide analytical results proving that MODiCuM can deter
misbehavior, and we evaluate the overhead of MODiCuM using experimental results
based on an implementation of our platform
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