5,586 research outputs found
Ion clustering in aqueous salt solutions near the liquid/vapor interface
Molecular dynamics simulations of aqueous NaCl, KCl, NaI, and KI solutions
are used to study the effects of salts on the properties of the liquid/vapor
interface. The simulations use the models which include both charge transfer
and polarization effects. Pairing and the formation of larger ion clusters
occurs both in the bulk and surface region, with a decreased tendency to form
larger clusters near the interface. An analysis of the roughness of the surface
reveals that the chloride salts, which have less tendency to be near the
surface, have a roughness that is less than pure water, while the iodide salts,
which have a greater surface affinity, have a larger roughness. This suggests
that ions away from the surface and ions near the surface affect the interface
in opposite ways.Comment: 10 pages, 5 figure
SUSY Faces its Higgs Couplings
In supersymmetric models, a correlation exists between the structure of the
Higgs sector quartic potential and the coupling of the lightest CP-even Higgs
to fermions and gauge bosons. We exploit this connection to relate the observed
value of the Higgs mass ~ 125 GeV to the magnitude of its couplings. We analyze
different scenarios ranging from the MSSM with heavy stops to more natural
models with additional non-decoupling D-term/F-term contributions. A comparison
with the most recent LHC data, allows to extract bounds on the heavy Higgs
boson masses, competitive with bounds from direct searches.Comment: 14 pages plus appendix; 9 figure
For the good of the group? Exploring group-level evolutionary adaptations using multilevel selection theory.
In this paper, we present an evolutionary framework, multilevel selection theory (MLS), that is highly amenable to existing social psychological theory and empiricism. MLS provides an interpretation of natural selection that shows how group-beneficial traits can evolve, a prevalent implication of social psychological data. We outline the theory and provide a number of example topics, focusing on prosociality, policing behavior, gossip, brainstorming, distributed cognition, and social identity. We also show that individual differences can produce important group-level outcomes depending on differential aggregation of individual types and relate this to the evolutionary dynamics underlying group traits. Drawing on existing work, we show how social psychologists can integrate this framework into their research program and suggest future directions for research
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