9,642 research outputs found
Expressiveness and Robustness of First-Price Position Auctions
Since economic mechanisms are often applied to very different instances of
the same problem, it is desirable to identify mechanisms that work well in a
wide range of circumstances. We pursue this goal for a position auction setting
and specifically seek mechanisms that guarantee good outcomes under both
complete and incomplete information. A variant of the generalized first-price
mechanism with multi-dimensional bids turns out to be the only standard
mechanism able to achieve this goal, even when types are one-dimensional. The
fact that expressiveness beyond the type space is both necessary and sufficient
for this kind of robustness provides an interesting counterpoint to previous
work on position auctions that has highlighted the benefits of simplicity. From
a technical perspective our results are interesting because they establish
equilibrium existence for a multi-dimensional bid space, where standard
techniques break down. The structure of the equilibrium bids moreover provides
an intuitive explanation for why first-price payments may be able to support
equilibria in a wider range of circumstances than second-price payments
Tunable Oscillations in the Purkinje Neuron
In this paper, we study the dynamics of slow oscillations in Purkinje neurons
in vitro, and derive a strong association with a forced parametric oscillator
model. We demonstrate the precise rhythmicity of the oscillations in Purkinje
neurons, as well as a dynamic tunability of this oscillation using a
photo-switchable compound. We show that this slow oscillation can be induced in
every Purkinje neuron, having periods ranging between 10-25 seconds. Starting
from a Hodgkin-Huxley model, we also demonstrate that this oscillation can be
externally modulated, and that the neurons will return to their intrinsic
firing frequency after the forced oscillation is concluded. These results
signify an additional functional role of tunable oscillations within the
cerebellum, as well as a dynamic control of a time scale in the brain in the
range of seconds.Comment: 12 pages, 5 figure
Detection and mapping of hydrothermally altered rocks in the vicinity of the comstock lode, Virginia Range, Nevada, using enhanced LANDSAT images
The author has identified the following significant results. LANDSAT images enhanced by the band-ratioing method can be used for reconnaissance alteration mapping in moderately heavily vegetated semiarid terrain as well as in sparsely vegetated to semiarid terrain where the technique was originally developed. Significant vegetation cover in a scene, however, requires the use of MSS ratios 4/5, 4/6, and 6/7 rather than 4/5, 5/6, and 6/7, and requires careful interpretation of the results. Supplemental information suitable to vegetation identification and cover estimates, such as standard LANDSAT false-color composites and low altitude aerial photographs of selected areas is desirable
Extreme objects with arbitrary large mass, or density, and arbitrary size
We consider a generalization of the interior Schwarzschild solution that we
match to the exterior one to build global C^1 models that can have arbitrary
large mass, or density, with arbitrary size. This is possible because of a new
insight into the problem of localizing the center of symmetry of the models and
the use of principal transformations to understand the structure of space.Comment: 20 pages, 6 figures. Fixed one reference. Added a new equatio
Higher Order Methods for Simulations on Quantum Computers
To efficiently implement many-qubit gates for use in quantum simulations on
quantum computers we develop and present methods reexpressing exp[-i (H_1 + H_2
+ ...) \Delta t] as a product of factors exp[-i H_1 \Delta t], exp[-i H_2
\Delta t], ... which is accurate to 3rd or 4th order in \Delta t. The methods
we derive are an extended form of symplectic method and can also be used for
the integration of classical Hamiltonians on classical computers. We derive
both integral and irrational methods, and find the most efficient methods in
both cases.Comment: 21 pages, Latex, one figur
Does Good Design Matter in the Seedstock Advertising Business? Effects of Graphic Design in Beef Seedstock Ads on Cattle Producers’ Trust and Credibility
Designers are trained professionals who understand how to effectively visually communicate based on executing principles of design and an understanding of their audience. Within the beef seedstock industry, ad design varies widely in terms of technical effectiveness, but how do those differences affect potential customers? This study tested the effects of seedstock ad’s graphic design on the viewer’s trust and credibility among 561 Angus cattle producers. Our results show the graphic design of a beef seedstock ranch ad promoting an upcoming bull sale did not influence producers’ perceptions of trust and credibility. However, results did reveal better designed ads are positively related to producers’ trust of that brand. We suggest the study results were influenced by a first impression established through the brand description presented to all treatment groups, which illustrates beef seedstock buyers may be more reliant on other informational cues than design to inform their purchasing decisions. Future research is needed to parcel out effects of the brand information relative to the design aspects of the ad
The relative importance of personal beliefs, meta-stereotypes and societal stereotypes of age for the wellbeing of older people
Negative images of old age can harm older individuals' cognitive and physical functioning and health. Yet, older people may be confronted with age stereotypes that are inconsistent with their own personal beliefs. We examine the implications for older people's wellbeing of three distinct elements of age stereotypes: their personal beliefs about their age group, their perception about how others generally perceive older people (i.e. their meta-stereotypes) and the societal age stereotypes that are empirically widely shared in society. Using measures from the Stereotype Content Model and survey data of older people from the United Kingdom (UK) (Study 1, N = 171), we found only partial overlap between older people's personal beliefs and their meta-stereotypes. Personal beliefs were unrelated to wellbeing, but positive meta-stereotypes of older people's competence were linked to higher wellbeing. These findings were largely replicated with a sample of baby-boomers from Switzerland (Study 2, N = 400) controlling for socio-demographics. Study 3 used representative survey data (N = 10,803) across 29 European countries, to test and confirm that the link between positive competence meta-stereotypes and wellbeing can be generalised to different cultures, and that positive warmth meta-stereotypes were an additional predictor. At the country level, societal age stereotypes about competence were positively related to the wellbeing of older people, but only in countries that provide greater opportunities for competence attainment.info:eu-repo/semantics/acceptedVersio
The structure of 2D semi-simple field theories
I classify all cohomological 2D field theories based on a semi-simple complex
Frobenius algebra A. They are controlled by a linear combination of
kappa-classes and by an extension datum to the Deligne-Mumford boundary. Their
effect on the Gromov-Witten potential is described by Givental's Fock space
formulae. This leads to the reconstruction of Gromov-Witten invariants from the
quantum cup-product at a single semi-simple point and from the first Chern
class, confirming Givental's higher-genus reconstruction conjecture. The proof
uses the Mumford conjecture proved by Madsen and Weiss.Comment: Small errors corrected in v3. Agrees with published versio
Classical simulation of noninteracting-fermion quantum circuits
We show that a class of quantum computations that was recently shown to be
efficiently simulatable on a classical computer by Valiant corresponds to a
physical model of noninteracting fermions in one dimension. We give an
alternative proof of his result using the language of fermions and extend the
result to noninteracting fermions with arbitrary pairwise interactions, where
gates can be conditioned on outcomes of complete von Neumann measurements in
the computational basis on other fermionic modes in the circuit. This last
result is in remarkable contrast with the case of noninteracting bosons where
universal quantum computation can be achieved by allowing gates to be
conditioned on classical bits (quant-ph/0006088).Comment: 26 pages, 1 figure, uses wick.sty; references added to recent results
by E. Knil
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