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