53,658 research outputs found
A HETEROSKEDASTIC NESTED RUM OF FRESHWATER FISHING
Choice set definition can be viewed as a nesting issue. Although the behavioral basis for grouping sites into nests is not well understood, one reason for grouping alternatives into nests may be the likelihood that they are "in" or "out" of an individual's choice set. However, a problem with using nests to evaluate choice set issues is that the researcher typically needs to impose the same nesting structure on all individuals and trips. Such an approach assumes that the degree of correlation among the alternatives does not vary across the sample. This paper develops and tests a more flexible nesting structure that allows the parameters on the inclusive values to vary systematically based on the sample demographics.Resource /Energy Economics and Policy,
A Trackable Model of Reciprocity and Fairness.
We introduced a parametric model of other-regarding preferences in which my emotional state determines the marginal rate of substitution between my own and other' payoffs, and thus my subsequent choices. In turn, my emotional state responds to relative status and to the kindness or unkindness of others' choices. Structural estimations of this model with six existing data sets demonstrate that other-regarding preferences depend on status, reciprocity, and perceived property rights.RECIPROCITY ; MARGINAL RATE OF SUBSTITUTION ; PAYOFFS
Another self-similar blast wave: Early time asymptote with shock heated electrons and high thermal conductivity
Accurate approximations are presented for the self-similar structures of nonradiating blast waves with adiabatic ions, isothermal electrons, and equation ion and electron temperatures at the shock. The cases considered evolve in cavities with power law ambient densities (including the uniform density case) and have negligible external pressure. The results provide the early time asymptote for systems with shock heating of electrons and strong thermal conduction. In addition, they provide analytical results against which two fluid numerical hydrodynamic codes can be checked
Saturn S-IB stage Final static test report, stage S-IB-2
Acceptance test firing of Saturn flight stage S-IB-
Extraordinary nonlinear plasmonics in graphene nanoislands
Nonlinear optical processes rely on the intrinsically weak interactions
between photons enabled by their coupling with matter. Unfortunately, many
applications in nonlinear optics are severely hindered by the small response of
conventional materials. Metallic nanostructures partially alleviate this
situation, as the large light enhancement associated with their localized
plasmons amplifies their nonlinear response to record high levels. Graphene
hosts long-lived, electrically tunable plasmons that also interact strongly
with light. Here we show that the nonlinear polarizabilities of graphene
nanoislands can be electrically tuned to surpass by several orders of magnitude
those of metal nanoparticles of similar size. This extraordinary behavior
extends over the visible and near-infrared for islands consisting of hundreds
of carbon atoms doped with moderate carrier densities. Our quantum-mechanical
simulations of the plasmon-enhanced optical response of nanographene reveal
this material as an ideal platform for the development of electrically tunable
nonlinear optical nanodevices.Comment: 16 pages, 12 figures, 54 reference
Studying the small scale ISM structure with supernovae
AIMS. In this work we explore the possibility of using the fast expansion of
a Type Ia supernova photosphere to detect extra-galactic ISM column density
variations on spatial scales of ~100 AU on time scales of a few months.
METHODS. We constructed a simple model which describes the expansion of the
photodisk and the effects of a patchy interstellar cloud on the observed
equivalent width of Na I D lines. Using this model we derived the behavior of
the equivalent width as a function of time, spatial scale and amplitude of the
column density fluctuations.
RESULTS. The calculations show that isolated, small (<100 AU) clouds with Na
I column densities exceeding a few 10^11 cm^-2 would be easily detected. In
contrast, the effects of a more realistic, patchy ISM become measurable in a
fraction of cases, and for peak-to-peak variations larger than ~10^12 cm^-2 on
a scale of 1000 AU.
CONCLUSIONS. The proposed technique provides a unique way to probe the
extra-galactic small scale structure, which is out of reach for any of the
methods used so far. The same tool can also be applied to study the sub-AU
Galactic ISM structure.Comment: 6 pages, 3 figures. Accepted for publication in Astronomy &
Astrophysic
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