6,615 research outputs found
A Careful Examination of the Live Nation-Ticketmaster Merger
As great admirers of The Boss and as fans of live entertainment, we share in the popular dismay over rising ticket prices for live performances. But we have been asked as antitrust scholars to examine the proposed merger of Live Nation and Ticketmaster, and we do so with the objectivity and honesty called for by The Boss’s quotes above. The proposed merger has been the target of aggressive attacks from several industry commentators and popular figures, but the legal and policy question is whether the transaction is at odds with the nation’s antitrust laws. One primary source of concern to critics is that Ticketmaster and Live Nation are two leading providers of ticket distribution services, and these critics argue that the merged entity would have a combined market share that is presumptively anticompetitive. We observe, however, that this transaction is taking place within a rapidly changing industry. The spread of Internet technologies has transformed the entertainment industry, and along with it the ticket distribution business such that a reliance on market shares based on historical sales is misleading. A growing number of venues, aided by a competitive bidding process that creates moments of focused competition, can now acquire the requisite capabilities to distribute tickets to their own events and can thus easily forgo reliance upon providers of outsourced distribution services. If self-distribution is an available and attractive option for venues, as it appears to be, then it is unlikely that even a monopolist provider of fully outsourced ticketing services could exercise market power. Ultimately, a proper assessment of the horizontal effects of this merger would have to weigh heavily the emerging role of Internet technologies in this dynamic business and the industry-wide trend towards self-distribution. The second category of arguments by critics opposing the merger rests on claims that vertical aspects of the transaction would produce anticompetitive effects. Indeed, Ticketmaster’s and Live Nation’s core businesses are in successive markets, and thus the proposed transaction is primarily a vertical merger, but there is broad agreement among economists and antitrust authorities that vertical mergers rarely introduce competitive concerns and are usually driven by efficiency motivations. This wealth of academic scholarship, which is reflected in current antitrust law, has not - from our vantage point - been properly incorporated into the public dialogue concerning the proposed merger. To the contrary, critics articulate concerns, including the fears that the merger would lead to the leveraging of market power and the foreclosure of downstream competition, that are refuted by accepted scholarship. Moreover, there are a number of specific efficiencies that, consistent with economic and organizational theory, are likely to emerge from a Live Nation-Ticketmaster merger and would be unlikely but for the companies’ integration. For these reasons, we submit this analysis in an effort to inform the debate with current economic and legal scholarship
Tunneling Spectroscopy of Disordered Two-Dimensional Electron Gas in the Quantum Hall Regime
Recently, Dial et al. presented measurements of the tunneling density of
states into the bulk of a two dimensional electron gas under strong magnetic
fields. Several high energy features appear in the measured spectrum showing a
distinct dependence on filling factor and a unique response to temperature. We
present a quantitative account of the observed structure, and argue it results
from the repulsive Coulomb interactions between the tunneling electron and
states localized at disorder potential wells. The quenching of the kinetic
energy by the applied magnetic field leads to an electron addition spectrum
that is primarily determined by the external magnetic field and is nearly
independent of the disorder potential. Using a Hartree-Fock model we reproduce
the salient features of the observed structure
ER Stress-Induced eIF2-alpha Phosphorylation Underlies Sensitivity of Striatal Neurons to Pathogenic Huntingtin
A hallmark of Huntington's disease is the pronounced sensitivity of striatal neurons to polyglutamine-expanded huntingtin expression. Here we show that cultured striatal cells and murine brain striatum have remarkably low levels of phosphorylation of translation initiation factor eIF2 alpha, a stress-induced process that interferes with general protein synthesis and also induces differential translation of pro-apoptotic factors. EIF2 alpha phosphorylation was elevated in a striatal cell line stably expressing pathogenic huntingtin, as well as in brain sections of Huntington's disease model mice. Pathogenic huntingtin caused endoplasmic reticulum (ER) stress and increased eIF2 alpha phosphorylation by increasing the activity of PKR-like ER-localized eIF2 alpha kinase (PERK). Importantly, striatal neurons exhibited special sensitivity to ER stress-inducing agents, which was potentiated by pathogenic huntingtin. We could strongly reduce huntingtin toxicity by inhibiting PERK. Therefore, alteration of protein homeostasis and eIF2 alpha phosphorylation status by pathogenic huntingtin appears to be an important cause of striatal cell death. A dephosphorylated state of eIF2 alpha has been linked to cognition, which suggests that the effect of pathogenic huntingtin might also be a source of the early cognitive impairment seen in patients
Secret-Sharing for NP
A computational secret-sharing scheme is a method that enables a dealer, that
has a secret, to distribute this secret among a set of parties such that a
"qualified" subset of parties can efficiently reconstruct the secret while any
"unqualified" subset of parties cannot efficiently learn anything about the
secret. The collection of "qualified" subsets is defined by a Boolean function.
It has been a major open problem to understand which (monotone) functions can
be realized by a computational secret-sharing schemes. Yao suggested a method
for secret-sharing for any function that has a polynomial-size monotone circuit
(a class which is strictly smaller than the class of monotone functions in P).
Around 1990 Rudich raised the possibility of obtaining secret-sharing for all
monotone functions in NP: In order to reconstruct the secret a set of parties
must be "qualified" and provide a witness attesting to this fact.
Recently, Garg et al. (STOC 2013) put forward the concept of witness
encryption, where the goal is to encrypt a message relative to a statement "x
in L" for a language L in NP such that anyone holding a witness to the
statement can decrypt the message, however, if x is not in L, then it is
computationally hard to decrypt. Garg et al. showed how to construct several
cryptographic primitives from witness encryption and gave a candidate
construction.
One can show that computational secret-sharing implies witness encryption for
the same language. Our main result is the converse: we give a construction of a
computational secret-sharing scheme for any monotone function in NP assuming
witness encryption for NP and one-way functions. As a consequence we get a
completeness theorem for secret-sharing: computational secret-sharing scheme
for any single monotone NP-complete function implies a computational
secret-sharing scheme for every monotone function in NP
Interview with director Jayan K. Cherian
In this interview with Judith Misrahi-Barak and Nicole Thiara, Jayan K. Cherian discusses his work as an independent filmmaker in India and the USA, his artistic and political commitment, and the challenges he has faced with the Central Board of Film Certification in India after the release of his first feature film Papilio Buddha (2013), which focuses on Dalit land struggles in Kerala, and again with his second feature film KaBodyscapes (2016). The interview explores how holding a dual status as an American citizen and an Overseas Citizen of India makes his situation more complex because it offers him both the freedom and constraints of being a permanent outsider. The discussion of Papilio Buddha and its representation of the Dalit land struggle is the focus of the interview. He also speaks about his intended audience(s) and the way he works on location with his crews. Since Cherian is a poet and a writer as well as a filmmaker, he explains his choices for specific media, in the particular contexts in which he positions himself
A New Approximate Min-Max Theorem with Applications in Cryptography
We propose a novel proof technique that can be applied to attack a broad
class of problems in computational complexity, when switching the order of
universal and existential quantifiers is helpful. Our approach combines the
standard min-max theorem and convex approximation techniques, offering
quantitative improvements over the standard way of using min-max theorems as
well as more concise and elegant proofs
Crystallization of the regulatory and effector domains of the key sporulation response regulator Spo0A
The key response-regulator gene of sporulation, spo0A, has been cloned from Bacillus stearothermophilus and the encoded protein purified. The DNA-binding and phospho-acceptor domains of Spo0A have been prepared by tryptic digestion of the intact protein and subsequently crystallized in forms suitable for X-ray crystallographic studies. The DNA-binding domain has been crystallized in two forms, one of which diffracts X-rays to beyond 2.5 Angstrom spacing. The crystals of the phospho-acceptor domain diffract X-rays beyond 2.0 Angstrom spacing using synchrotron radiation
Chiral crystals in strong-coupling lattice QCD at nonzero chemical potential
We study the effective action for strong-coupling lattice QCD with
one-component staggered fermions in the case of nonzero chemical potential and
zero temperature. The structure of this action suggests that at large chemical
potentials its ground state is a crystalline `chiral density wave' that
spontaneously breaks chiral symmetry and translation invariance. In mean-field
theory, on the other hand, we find that this state is unstable. We show that
lattice artifacts are partly responsible for this, and suggest that if this
phase exists in QCD, then finding it in Monte-Carlo simulations would require
simulating on relatively fine lattices. In particular, the baryon mass in
lattice units, m_B, should be considerably smaller than its strong-coupling
limit of m_B~3.Comment: 33 pages, 8 figure
Nonlinear interactions with an ultrahigh flux of broadband entangled photons
We experimentally demonstrate sum-frequency generation (SFG) with entangled
photon-pairs, generating as many as 40,000 SFG photons per second, visible even
to the naked eye. The nonclassical nature of the interaction is exhibited by a
linear intensity-dependence of the nonlinear process. The key element in our
scheme is the generation of an ultrahigh flux of entangled photons while
maintaining their nonclassical properties. This is made possible by generating
the down-converted photons as broadband as possible, orders of magnitude wider
than the pump. This approach is readily applicable for other nonlinear
interactions, and may be applicable for various quantum-measurement tasks.Comment: 4 pages, 2 figures, Accepted to Phys. Rev. Let
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