7,621 research outputs found
InnovativeTeacher – Enhanced IT Skills in Education
In this paper we will describe the main criteria for the methodology handbook, the organisation of the repository and as well as the integration of the repository in Moodle eLearning platform as main communication basis for communication between teachers communities. We present also the results of a first teacher’s training with the instruments developed in the project
New Developments in FormCalc 8.4
We present new developments in FeynArts 3.9 and FormCalc 8.4, in particular
the MSSMCT model file including the complete one-loop renormalization,
vectorization/parallelization issues, and the interface to the Ninja library
for tensor reduction.Comment: 7 pages, proceedings contribution to Loops & Legs 2014, April 27-May
2, 2014, Weimar, German
The Implementation of the Renormalized Complex MSSM in FeynArts and FormCalc
We describe the implementation of the renormalized complex MSSM (cMSSM) in
the diagram generator FeynArts and the calculational tool FormCalc. This
extension allows to perform UV-finite one-loop calculations of cMSSM processes
almost fully automatically. The Feynman rules for the cMSSM with counterterms
are available as a new model file for FeynArts. Also included are default
definitions of the renormalization constants; this fixes the renormalization
scheme. Beyond that all model parameters are generic, e.g. we do not impose any
relations to restrict the number of input parameters. The model file has been
tested extensively for several non-trivial decays and scattering reactions. Our
renormalization scheme has been shown to give stable results over large parts
of the cMSSM parameter space.Comment: 29 pages, extended chargino/neutralino and sfermion renormalization
schemes, version accepted for publication in Comp. Phys. Commu
Neutrino Oscillation Experiments at Nuclear Reactors
In this paper I give an overview of the status of neutrino oscillation
experiments performed using nuclear reactors as sources of neutrinos. I review
the present generation of experiments (Chooz and Palo Verde) with baselines of
about 1 km as well as the next generation that will search for oscillations
with a baseline of about 100 km. While the present detectors provide essential
input towards the understanding of the atmospheric neutrino anomaly, in the
future, the KamLAND reactor experiment represents our best opportunity to study
very small mass neutrino mixing in laboratory conditions. In addition KamLAND
with its very large fiducial mass and low energy threshold, will also be
sensitive to a broad range of different physics.Comment: 10 pages, 5 figures To appear in the proceedings of WIN99, Cape Town,
South Africa, Jan9
On the ignorance of group-level effects – The tragedy of personnel evaluation?
In social-dilemma situations (e.g., public-good games), people may pursue their local self- interests, thereby lowering the overall payoff of their group and, paradoxically, even their individual payoffs as a result. Likewise, in inner-individual dilemmas, even without conflict of interest between persons, people may pursue local goals at the expense of overall utility. Our experiments investigate such dissociations of individual and group-level effects in the context of personnel evaluation and selection. Participants were given the role of human resource managers selecting workers to optimize the overall payoff for the company. We investigated contexts where the individually best/worst ‘employees’ systematically caused the worst/best group performance. When workers in a team could substantially increase or decrease co-workers’ performance, most participants (albeit not all) tended to focus solely on individual performance without considering their overall contribution even when instructed to maximize group performance. This undue focus on individual information meant that employees who enhanced team performance the most often received the most negative evaluations. This may result in a ‘tragedy of personnel evaluation’ relevant to maladaptive incentive structures (personnel evaluation), job offers (personnel selection), and a substantially negative impact on organizational effectiveness. At the same time, the results suggest ways this problem may be overcome
The Temporal Dynamics of Belief-based Updating of Epistemic Trust: Light at the End of the Tunnel?
We start with the distinction of outcome- and belief-based Bayesian models of
the sequential update of agents' beliefs and subjective reliability of sources
(trust). We then focus on discussing the influential Bayesian model of
belief-based trust update by Eric Olsson, which models dichotomic events and
explicitly represents anti-reliability. After sketching some disastrous recent
results for this perhaps most promising model of belief update, we show new
simulation results for the temporal dynamics of learning belief with and
without trust update and with and without communication. The results seem to
shed at least a somewhat more positive light on the
communicating-and-trust-updating agents. This may be a light at the end of the
tunnel of belief-based models of trust updating, but the interpretation of the
clear findings is much less clear.Comment: 7 pages, 6 figures. The paper was presented 2019 at the TeaP in
London and at the 41st Annual Meeting of the Cognitive Science Society in
Montreal (Canada). We intend to submit an extended and improved version for
publication in a journa
Formal models of source reliability
The paper introduces, compares and contrasts formal models of source reliability proposed in the epistemology literature, in particular the prominent models of Bovens and Hartmann (2003) and Olsson (2011). All are Bayesian models seeking to provide normative guidance, yet they differ subtly in assumptions and resulting behavior. Models are evaluated both on conceptual grounds and through simulations, and the relationship between models is clarified. The simulations both show surprising similarities and highlight relevant differences between these models. Most importantly, however, our evaluations reveal that important normative concerns arguably remain unresolved. The philosophical implications of this for testimony are discussed
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Thinking Locally or Globally? – Trying to Overcome the Tragedy of Personnel Evaluation with Stories or Selective Information Presentation
Social dilemmas conceptually suggest distinguishing direct
individual and group-level effects (also involving indirect
effects on others). Furthermore, the success of organizations
appears to rely on identifying not only individual excellence
but positive impact on others as well. In ‘Two-Level
Personnel Evaluation Tasks’ (T-PETs) participants as human
resource managers evaluate employees when individual and
group contributions are dissociated. Von Sydow, Braus, &
Hahn (2018) have suggested a potential ‘Tragedy of
Personnel Evaluation’: A group-serving employee with the
smallest individual contribution but by far the greatest po-
sitive effect on the group’s overall earnings was often rated
the most negatively. Here we investigate, in two experiments
with conflicting information, whether emphasizing the group
can avert the ‘tragic’ outcome. Our results suggest that the
tragedy is not as complete as suggested, and that contextual
information can mitigate the tragedy. Nonetheless, the results
also corroborate the stability of underestimating the impact of
team players
Oxidized low-density lipoprotein inhibits hepatitis C virus cell entry in human hepatoma cells.
Cell entry of hepatitis C virus, pseudoparticles (HCVpp) and cell culture grown virus (HCVcc), requires the interaction of viral glycoproteins with CD81 and other as yet unknown cellular factors. One of these is likely to be the scavenger receptor class B type I (SR-BI). To further understand the role of SR-BI, we examined the effect of SR-BI ligands on HCVpp and HCVcc infectivity. Oxidized low-density lipoprotein (oxLDL), but not native LDL, potently inhibited HCVpp and HCVcc cell entry. Pseudoparticles bearing unrelated viral glycoproteins or bovine viral diarrhea virus were not affected. A dose-dependent inhibition was observed for HCVpp bearing diverse viral glycoproteins with an approximate IC50 of 1.5 microg/mL apolipoprotein content, which is within the range of oxLDL reported to be present in human plasma. The ability of lipoprotein components to bind to target cells associated with their antiviral activity, suggesting a mechanism of action which targets a cell surface receptor critical for HCV infection of the host cell. However, binding of soluble E2 to SR-BI or CD81 was not affected by oxLDL, suggesting that oxLDL does not act as a simple receptor blocker. At the same time, oxLDL incubation altered the biophysical properties of HCVpp, suggesting a ternary interaction of oxLDL with both virus and target cells. In conclusion, the SR-BI ligand oxLDL is a potent cell entry inhibitor for a broad range of HCV strains in vitro. These findings suggest that SR-BI is an essential component of the cellular HCV receptor complex
Diverse CD81 proteins support hepatitis C virus infection.
Hepatitis C virus (HCV) entry is dependent on CD81. To investigate whether the CD81 sequence is a determinant of HCV host range, we expressed a panel of diverse CD81 proteins and tested their ability to interact with HCV. CD81 large extracellular loop (LEL) sequences were expressed as recombinant proteins; the human and, to a low level, the African green monkey sequences bound soluble HCV E2 (sE2) and inhibited infection by retrovirus pseudotype particles bearing HCV glycoproteins (HCVpp). In contrast, mouse or rat CD81 proteins failed to bind sE2 or to inhibit HCVpp infection. However, CD81 proteins from all species, when expressed in HepG2 cells, conferred susceptibility to infection by HCVpp and cell culture-grown HCV to various levels, with the rat sequence being the least efficient. Recombinant human CD81 LEL inhibited HCVpp infectivity only if present during the virus-cell incubation, consistent with a role for CD81 after virus attachment. Amino acid changes that abrogate sE2 binding (I182F, N184Y, and F186S, alone or in combination) were introduced into human CD81. All three amino acid changes in human CD81 resulted in a molecule that still supported HCVpp infection, albeit with reduced efficiency. In summary, there is a remarkable plasticity in the range of CD81 sequences that can support HCV entry, suggesting that CD81 polymorphism may contribute to, but alone does not define, the HCV susceptibility of a species. In addition, the capacity to support viral entry is only partially reflected by assays measuring sE2 interaction with recombinant or full-length CD81 proteins
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